JP4984762B2 - Light diffusing resin composition, molded product thereof and light guide - Google Patents

Description

  The present invention comprises a light diffusing resin composition containing a cyclic olefin-based resin and particles each having at least one maximum value in specific two regions of particle size distribution, and the light diffusing resin composition is molded. The present invention relates to a light diffusing molded article and a light guide used for an edge light type backlight of a liquid crystal display device.

  Conventionally, as a light source of an edge light type backlight, a linear light source such as a cold cathode tube or a linear light guide has been used. However, in response to recent demands for improving the luminance of backlights and reducing power consumption, light sources using one or more point light sources such as LEDs are becoming mainstream. In this case, a light guide is used so that light from the light source spreads uniformly over the entire screen of a liquid crystal display device or the like.

  When a backlight light guide using a point light source is used as an illuminating device for a liquid crystal display device, there is a problem that bright lines are generated in the vicinity of the light source and local luminance unevenness occurs. As a method for solving this problem, a method is adopted in which light scattering particles are dispersed in a light guide to make the luminance near the light source uniform (for example, Japanese Patent Laid-Open No. 6-624330 (Patent Document 1)). reference).

  Conventionally, inorganic particles such as glass, silicon dioxide, calcium carbonate, zirconia, and silicon resin, and organic polymer particles that are polymerized and cross-linked based on acrylic monomers and styrene monomers as main components are used to provide these light diffusing functions. Is used.

However, in recent years, with the increase in brightness of displays, high-brightness LEDs have come to be used as light sources, and there is a particular demand for compatibility between light diffusibility and light transmission, which are conventionally known inorganic particles. Or in the light diffusable resin composition which disperse | distributed organic particle, it was difficult to make such performance compatible.
JP-A-6-624330

  An object of the present invention is to solve the problems associated with the prior art as described above, and is a molded article excellent in balance between brightness (high luminance), light diffusion performance and hue uniformity, particularly a lead. It is in providing a light body and providing the light diffusable resin composition for manufacturing this molded article.

  As a result of diligent research to solve the above problems, the present inventors have determined that the cyclic olefin-based resin has particles having at least one maximum value in each of two specific regions of the particle size distribution, more preferably an average particle size. It has been found that a plate-like molded article having an excellent balance of brightness, light diffusion performance and hue uniformity can be obtained from a resin composition in which two kinds of particles in a specific range are mixed and dispersed. As a result, the present inventors have found that the molded article is useful as a light guide for an edge light type backlight for a liquid crystal display device, and has completed the present invention.

That is, the light diffusing resin composition according to the present invention contains the cyclic olefin-based resin (A) and the particles (B), and the content ratio of the particles (B) is based on the weight based on 100% by weight of the total. The particle (B) has at least one maximum value in each of a region having a particle size of less than 4.0 μm and a region of 4.0 μm or more in the volume-based particle size distribution. It is characterized by that.

  The particles (B) can be easily obtained by mixing particles (B1) having a volume-based average particle size of 4.0 μm or more and particles (B2) having an average particle size of less than 4.0 μm. Can do.

In the volume-based particle size distribution of the particles (B1), when the peak having the largest peak area is represented by a lognormal distribution, the geometric standard deviation σg _B1 is preferably 1.0 or more and 2.0 or less, In the volume-based particle size distribution of the particles (B2), the geometric standard deviation σg _B2 is preferably 1.0 or more and 2.0 or less when the peak having the largest peak area is represented by a lognormal distribution.

The absolute value of the difference between the refractive index n _B1 cycloolefin refractive index n _A and the particles of the resin (A) (B1) | n B1 -n A | is preferably is 0.04 or more, the annular absolute value of the difference between the refractive index n _B2 of the refractive index n _a and the particles of the olefin resin (a) (B2) | n B2 -n a | is preferably 0.04 or more.

At least some of the particles (B) are preferably hollow particles, and at least some of the particles (B) are preferably organic crosslinked particles.
The molded article according to the present invention and the light guide for the edge-light type backlight of the liquid crystal display device are formed by injection molding the light diffusing resin composition.

  According to the present invention, it is possible to obtain a resin composition capable of obtaining a molded product excellent in molding processability and high-temperature stability, and having an excellent balance of brightness, light diffusion performance, and hue uniformity, and the molded product. This molded product is useful as a light guide for an edge light type backlight of a liquid crystal display device.

The light diffusing resin composition according to the present invention contains a cyclic olefin resin (A) and particles (B). First, these components will be described.
(A) Cyclic olefin resin:
Examples of the cyclic olefin resin (A) used in the present invention include a (co) polymer of a cyclic olefin represented by the following formula (I) (hereinafter also referred to as “cyclic olefin (I)”).

In formula (I), R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom or a monovalent organic group, and R ¹ and R ² , or R ³ and R ⁴ are integrated to form a divalent group. R ¹ or R ² and R ³ or R ⁴ may be bonded to each other to form a monocyclic structure or a polycyclic structure. m is 0 or a positive integer, and p is 0 or a positive integer.

As a more specific cyclic olefin resin (A),
(1) Ring-opening polymer of cyclic olefin (I) (hereinafter also referred to as “polymer (1)”)
(2) Ring-opening copolymer of cyclic olefin (I) and copolymerizable monomer (hereinafter also referred to as “polymer (2)”)
(3) Hydrogenated (co) polymer of polymer (1) or polymer (2) (hereinafter also referred to as “polymer (3)”)
(4) Polymer (1) or polymer (2) cyclized by Friedel-Craft reaction and then hydrogenated (co) polymer (hereinafter also referred to as “polymer (4)”)
(5) Saturated copolymer of cyclic olefin (I) and unsaturated double bond-containing compound (hereinafter also referred to as “polymer (5)”)
(6) Addition type (co) polymer of cyclic olefin (I) and at least one monomer selected from vinyl cyclic hydrocarbon monomers and cyclopentadiene monomers, and hydrogenation thereof ( Co) polymer (hereinafter also referred to as “polymer (6)”)
(7) Alternating copolymer of cyclic olefin (I) and acrylate (hereinafter also referred to as “polymer (7)”)
Is mentioned. Of these, the polymer (3) is particularly preferably used in terms of excellent transparency and the like.

<Cyclic olefin (I)>
Examples of the monovalent organic group in the above formula (I) include C1-C30 hydrocarbon groups and monovalent polar groups other than hydrocarbon groups. Examples of the monovalent polar group include a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group. These polar groups are bonded via a linking group such as a methylene group. You may do it. Moreover, the hydrocarbon group etc. which couple | bonded through the coupling group which consists of divalent organic groups, such as a carbonyl group, an ether group, a silyl ether group, a thioether group, and an imino group, are also mentioned as a polar group. Of these polar groups, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, and an allyloxycarbonyl group are preferable, and an alkoxycarbonyl group and an allyloxycarbonyl group are particularly preferable.

The cyclic olefin represented by the above formula (I) may be used alone or in combination of two or more.
Examples of the cyclic olefin represented by the formula (I) include, but are not limited to, the following compounds.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [2.2.1] hept-2-ene,
5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-cyanobicyclo [2.2.1] hept-2-ene,
8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ]
-3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-fluorobicyclo [2.2.1] hept-2-ene,
5-fluoromethylbicyclo [2.2.1] hept-2-ene,
5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,
5,5-difluorobicyclo [2.2.1] hept-2-ene,
5,6-difluorobicyclo [2.2.1] hept-2-ene,
5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,
8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene,
8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] −
3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene.

Among such cyclic olefins, in the above formula (I), R ¹ and R ³ are each independently a hydrogen atom or a carbon number of preferably 1 to 10, more preferably 1 to 4, particularly preferably 1 or 2. A hydrocarbon group, preferably an alkyl group, particularly preferably a methyl group; R ² and R ⁴ are each independently a hydrogen atom or a monovalent organic group, and at least one of R ² and R ⁴ is A hydrogen atom or the above-mentioned monovalent polar group; m is preferably an integer of 0 to 3, p is preferably an integer of 0 to 3, more preferably m + p is 0 to 4, and particularly preferably m + p is 0 to 2. And most preferred is a cyclic olefin in which m = 1 and p = 0. Cyclic olefins with m = 1 and p = 0 are most preferable in that a cyclic olefin-based resin having a high glass transition temperature and excellent mechanical strength can be obtained.

Furthermore, the cyclic olefin in which at least one of R ² and R ⁴ is a polar group represented by the following formula (II) has high glass transition temperature, low hygroscopicity, and excellent adhesion to various materials. It is preferable at the point from which a cyclic olefin resin is obtained.

_{- (CH 2) n COOR (} II)
In the formula (II), R is preferably a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, particularly preferably 1 or 2, and preferably an alkyl group. Further, n is usually 0 to 5, and a cyclic olefin having a smaller value of n is preferable because a cyclic olefin-based resin having a high glass transition temperature is obtained, and a cyclic olefin having n of 0 is easy to synthesize. Is particularly preferable.

In particular, the polar group represented by the above formula (II) is bonded to the carbon atom to which R ¹ or R ³ which is an alkyl group is bonded, so that a cyclic olefin resin having low hygroscopicity is obtained. This is preferable.

Polymer (1) and polymer (2):
The polymer (1) and the polymer (2) are obtained by ring-opening polymerization of the cyclic olefin or ring-opening copolymerization of the cyclic olefin and a copolymerizable monomer in the presence of a metathesis catalyst. Obtainable.

<Copolymerizable monomer>
Examples of the copolymerizable monomer used in the polymer (2) include cycloolefin, and a cycloolefin having 4 to 20 carbon atoms, more preferably 5 to 12 carbon atoms is desirable. More specifically, cyclobutene, cyclopentene, cycloheptene, cyclooctene, dicyclopentadiene and the like can be mentioned. These cycloolefins may be used alone or in combination of two or more.
The use ratio of the cyclic olefin and the copolymerizable monomer is preferably 100/0 to 50/50, more preferably 100/0 to 60/40 in terms of weight ratio (cyclic olefin / copolymerizable monomer). . “Cyclic olefin / copolymerizable monomer = 100/0” means the proportion of cyclic olefin used in homopolymerization.

<Catalyst for ring-opening polymerization>
The metathesis catalyst used in the ring-opening (co) polymerization reaction is a catalyst comprising a combination of the following compound (a) and compound (b).
(A) A compound containing at least one element selected from W, Mo and Re.
(B) Deming periodic table group IA elements (for example, Li, Na, K, etc.), group IIA elements (for example, Mg, Ca, etc.), group IIB elements (for example, Zn, Cd, Hg, etc.), group IIIA A compound containing at least one element selected from an element (eg, B, Al, etc.), a group IVA element (eg, Si, Sn, Pb, etc.) and a group IVB element (eg, Ti, Zr, etc.), At least one compound selected from compounds having at least one bond between an element and carbon or at least one bond between the element and hydrogen.

The metathesis catalyst may contain an additive (c) described later in order to increase its activity.
Specific examples of the compound (a) include WCl ₆ , MoCl ₆ , ReOCl _3, etc., described in JP-A No. 1-132626, page 8, upper left column, line 6 to page 8, upper right column, line 17. Can be mentioned.

Specific examples of the compound (b) include n-C ₄ H ₉ Li, (C ₂ H ₅ ) ₃ Al, and (C ₂ H ₅ ) _2.
AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅ ) AlCl ₂ , methylalumoxane, L
Examples include iH and the compounds described in JP-A-1-132626, page 8, upper right column, line 18 to page 8, lower right column, line 3.

  As the additive (c), alcohols, aldehydes, ketones, amines and the like can be preferably used, and further, JP-A-1-132626, page 8, lower right column, lines 16 to 9. The compounds described in the upper left column, line 17 of the page can also be used.

The ratio of the said compound (a) and a compound (b) is metal atom ratio [(a) :( b)], and is usually 1: 1-1: 50, Preferably it is 1: 2-1: 30.
The ratio of the additive (c) to the compound (a) is a molar ratio [(c) :( a)] and is usually 0.005: 1 to 15: 1, preferably 0.05: 1 to 7: 1.

  The amount of the metathesis catalyst used is such that the molar ratio of the compound (a) to the cyclic olefin [(a): cyclic olefin] is usually from 1: 500 to 1: 50,000, preferably from 1: 1,000 to 1:10. , 000.

<Solvent for polymerization reaction>
In the ring-opening (co) polymerization reaction, the solvent is used as a solvent constituting a molecular weight modifier solution described later, a solvent for a cyclic olefin and / or a metathesis catalyst. Examples of such solvents include alkanes such as pentane, hexane, heptane, octane, nonane and decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin and norbornane; benzene, toluene, xylene, ethylbenzene, Aromatic hydrocarbons such as cumene; halogenated alkanes such as chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylene dibromide, chloroform, tetrachloroethylene; aryl halides such as chlorobenzene; ethyl acetate, n-butyl acetate, iso- Saturated carboxylic acid esters such as butyl, methyl propionate, and dimethoxyethane; and ethers such as dibutyl ether, tetrahydrofuran, and dimethoxyethane. That. These solvents can be used alone or in combination. Of these, aromatic hydrocarbons are preferred.

The amount of the solvent used is desirably such that the weight ratio of the solvent to the cyclic olefin (solvent: cyclic olefin) is usually 1: 1 to 10: 1, preferably 1: 1 to 5: 1.
<Molecular weight regulator>
The molecular weight of the resulting ring-opening (co) polymer can be adjusted by the polymerization temperature, the type of catalyst and the type of solvent, but can also be adjusted by allowing a molecular weight regulator to coexist in the reaction system. .

  Suitable molecular weight regulators include, for example, α-olefins such as ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and styrene. Of these, 1-butene and 1-hexene are particularly preferable. These molecular weight regulators can be used alone or in admixture of two or more.

The usage-amount of a molecular weight regulator is 0.005-0.6 mol normally with respect to 1 mol of cyclic olefins used for ring-opening polymerization reaction, Preferably it is 0.01-0.5 mol.
The ring-opening copolymer can be obtained by ring-opening copolymerization of a cyclic olefin and a copolymerizable monomer, and further includes conjugated diene compounds such as polybutadiene and polyisoprene, styrene-butadiene copolymer, Cyclic olefins may be subjected to ring-opening copolymerization in the presence of an unsaturated hydrocarbon polymer containing two or more carbon-carbon double bonds in the main chain such as an ethylene-nonconjugated diene copolymer or polynorbornene. .

(3) Hydrogenated (co) polymer:
The ring-opening (co) polymer can be used as it is, but the hydrogenated (co) polymer (3) obtained by further hydrogenation thereof is useful as a resin having excellent impact resistance. .

  In the hydrogenation reaction, a hydrogenation catalyst is added to an ordinary method, that is, a solution containing a ring-opening (co) polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added thereto at 0 to 200 ° C. , Preferably, it can be carried out by acting at 20 to 180 ° C.

<Hydrogenation catalyst>
As said hydrogenation catalyst, the catalyst used for the hydrogenation reaction of a normal olefinic compound can be used. Examples of the hydrogenation catalyst include a heterogeneous catalyst and a homogeneous catalyst.

  Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst material such as palladium, platinum, nickel, rhodium, and ruthenium is supported on a carrier such as carbon, silica, alumina, and titania. Homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium, dichloro Examples thereof include tris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium, and the like. The form of these catalysts may be powder or granular.

In these hydrogenation catalysts, the weight ratio of the ring-opening (co) polymer to the hydrogenation catalyst (ring-opening (co) polymer: hydrogenation catalyst) is 1: 1 × 10 ⁻⁶ to 1: 2. It is preferable to use in proportions.

The hydrogenated (co) polymer (3) has excellent thermal stability, and its characteristics are not deteriorated even by heating during molding or use as a product.
The hydrogenation rate of the hydrogenated (co) polymer (3) is usually 50% or more, preferably 70% or more, more preferably 90% or more, particularly preferably as measured by ¹ H-NMR under the condition of 500 MHz. 98% or more, most preferably 99% or more. The higher the hydrogenation rate, the better the stability to heat and light, and it is possible to obtain a molded article such as a light guide having stable characteristics over a long period of time.

The hydrogenated (co) polymer (3) preferably has a gel content of 5% by weight or less, particularly preferably 1% by weight or less.
(4) Hydrogenated (co) polymer:
The hydrogenated (co) polymer (4) can be obtained by cyclizing the ring-opened (co) polymer of (1) or (2) by Friedel-Craft reaction and then hydrogenating it.

  The method for cyclizing the ring-opened (co) polymer by Friedel-Craft reaction is not particularly limited, and for example, a known method using an acidic compound described in JP-A No. 50-154399 can be employed.

Specific examples of the acidic compound include AlCl ₃ , BF ₃ , FeCl ₃ , Al ₂ O ₃ , HCl
, CH ₃ ClCOOH, zeolite, Lewis acid such as activated clay, and Bronsted acid.

The cyclized ring-opening (co) polymer can be hydrogenated in the same manner as the hydrogenation reaction of the ring-opening (co) polymer.
(5) Saturated copolymer:
The saturated copolymer (5) can be obtained by addition polymerization of an unsaturated double bond-containing compound to the cyclic olefin in the presence of an addition polymerization catalyst. A conventionally known method can be applied to the addition polymerization method.

<Unsaturated double bond-containing compound>
Examples of the unsaturated double bond-containing compound include olefinic compounds such as ethylene, propylene, and butene. Among these, olefinic compounds having preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms. Compounds are desirable.

  The use amount of the unsaturated double bond-containing compound is preferably 90/10 to 40/60 in terms of the weight ratio of the cyclic olefin to the unsaturated double bond-containing compound (cyclic olefin / unsaturated double bond-containing compound). 85/15 to 50/50 is more preferable. However, the total weight of the cyclic olefin and the unsaturated double bond-containing compound is 100.

<Addition polymerization catalyst>
Examples of the addition polymerization catalyst include a combination of at least one compound selected from a titanium compound, a zirconium compound, and a vanadium compound, and an organoaluminum compound as a co-catalyst.

Examples of the titanium compound include titanium tetrachloride and titanium trichloride. Examples of the zirconium compound include bis (cyclopentadienyl) zirconium chloride and bis (cyclopentadienyl) zirconium dichloride. As the vanadium compound, the following formula VO (OR) _a X _b or V (OR) _c X _d
[Wherein R is a hydrocarbon group, X is a halogen atom, and 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ (a + b) ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3, ≦ (c + d) ≦ 4. ]
Or an electron-donating adduct of these compounds.

  Examples of the electron donor include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic acids or inorganic acids, ethers, acid amides, acid anhydrides, oxygen-containing electron donors such as alkoxysilanes, ammonia, amines, Examples thereof include nitrogen-containing electron donors such as nitrile and isocyanate.

  Examples of the organoaluminum compound include compounds having at least one aluminum-carbon bond or aluminum-hydrogen bond. These organoaluminum compounds may be used alone or in combination of two or more.

  The ratio of the amount used of a compound selected from a titanium compound, a zirconium compound and a vanadium compound (the total amount when two or more are used together) and the amount of the organoaluminum compound used is the ratio of aluminum atoms to titanium atoms ( Al / Ti etc.), usually 2 or more, preferably 2 to 50, particularly preferably 3 to 20.

Examples of the solvent used in the addition polymerization reaction include the solvents exemplified in the ring-opening (co) polymerization reaction.
Moreover, the molecular weight of the saturated copolymer (5) can be usually adjusted using hydrogen.

(6) Addition type (co) polymer and hydrogenated (co) polymer thereof:
The addition type (co) polymer (6) is obtained by subjecting the cyclic olefin to addition polymerization of at least one monomer selected from a vinyl cyclic hydrocarbon monomer and a cyclopentadiene monomer. Obtainable.

<Vinyl cyclic hydrocarbon monomer>
Examples of the vinyl cyclic hydrocarbon monomer include vinylcyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene, 4-vinylcyclopentane, and 4-isopropenylcyclopentane. Vinylated 5-membered hydrocarbon monomers such as vinylcyclopentane monomers such as 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-isopropenylcyclohexene, 2-methyl-4- Vinylcyclohexene, vinylcyclohexene monomers such as 2-methyl-4-isopropenylcyclohexene, vinylcyclohexane monomers such as 4-vinylcyclohexane and 2-methyl-4-isopropenylcyclohexane, styrene, α-methylstyrene , 2-methylstyrene Styrene monomers such as 3-methylstyrene, 4-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-phenylstyrene, p-methoxystyrene, d-terpene, 1-terpene, diterpene, d-limonene Terpene monomers such as 1-limonene and dipentene, vinylcycloheptene monomers such as 4-vinylcycloheptene and 4-isopropenylcycloheptene, 4-vinylcycloheptane, 4-isopropenylcyclo Examples thereof include vinylcycloheptane monomers such as heptane. Of these monomers, styrene and α-methylstyrene are preferred. Moreover, these monomers may be used individually by 1 type, or may use 2 or more types together.

<Cyclopentadiene monomer>
Examples of the cyclopentadiene monomer include cyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene, 2-ethylcyclopentadiene, 5-methylcyclopentadiene, 5,5-methylcyclopentadiene, and the like. . Of these monomers, cyclopentadiene is preferred. Moreover, these monomers may be used individually by 1 type, or may use 2 or more types together.

The above addition polymerization reaction can be carried out in the same manner as the addition polymerization reaction in the saturated copolymer (5).
The hydrogenation (co) polymer of the addition type (co) polymer (6) is obtained by subjecting the addition type (co) polymer (6) to the same method as the hydrogenation (co) polymer (3). It can be obtained by hydrogenation.

(7) Alternating copolymer:
The alternating copolymer (7) can be obtained by radical polymerization of the cyclic olefin and acrylate in the presence of a Lewis acid or the like.

<Acrylate>
Examples of the acrylate include linear, branched or cyclic alkyl acrylates having 1 to 20 carbon atoms such as methyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate; carbon atoms such as glycidyl acrylate and 2-tetrahydrofurfuryl acrylate. An acrylate having 2 to 20 heterocyclic groups; an acrylate having 6 to 20 carbon atoms such as benzyl acrylate; a polycyclic structure having 7 to 30 carbon atoms such as isobornyl acrylate and dicyclopentanyl acrylate The acrylate which has.

The ratio of the cyclic olefin to the acrylate is generally 30 to 70 mol of cyclic olefin and 70 to 30 mol of acrylate, preferably 40 to 60 mol of cyclic olefin, and acrylate It is 60-40 mol, Most preferably, a cyclic olefin is 45-55 mol, and an acrylate is 55-45 mol.

As for the usage-amount of the said Lewis' acid, 0.001-1 mol is preferable with respect to 100 mol of acrylates.
In addition, known organic peroxides or azobis-based radical polymerization initiators that generate free radicals can also be used.

  The polymerization reaction temperature is usually -20 ° C to 80 ° C, preferably 5 ° C to 60 ° C. Moreover, as a solvent for polymerization reaction, the solvent illustrated in the said ring-opening (co) polymerization reaction can be mentioned.

  The “alternate copolymer” in the present invention is a copolymer in which structural units derived from cyclic olefins are not adjacent to each other, that is, a structural unit derived from acrylate is always adjacent to a structural unit derived from cyclic olefin. It means a copolymer that is bonded. However, the acrylate-derived structural units may be present adjacent to each other.

The intrinsic viscosity [η _inh ] of the cyclic olefin resin used in the present invention is 0.2 to 5 dl /
g is preferable, 0.3 to 3 dl / g is more preferable, and 0.4 to 1.5 dl / g is particularly preferable. Moreover, the molecular weight of polystyrene conversion measured by gel permeation chromatography (GPC, column: TSKgel G7000HXL × 1, TSKgel GMHXL × 2 and TSKgel G2000HXL × 1 in series) using tetrahydrofuran as a solvent, The number average molecular weight (Mn) is preferably 8,000 to 100,000, more preferably 10,000 to 80,000, particularly preferably 12,000 to 50,000, and the weight average molecular weight (Mw) is preferably It is 20,000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 40,000 to 200,000.

Cyclic olefin resins having intrinsic viscosity [η _inh ], number average molecular weight (Mn) and weight average molecular weight (Mw) in the above ranges are excellent in moldability and heat resistance, water resistance, chemical resistance, mechanical A molded product having excellent characteristics can be obtained.

  Moreover, the glass transition temperature (Tg) of the said cyclic olefin resin is 130 degreeC or more normally, Preferably it is 130-350 degreeC, More preferably, it is 130-250 degreeC, Most preferably, it is 140-200 degreeC. Resins with a Tg in the above range are not easily deformed even when used under high temperature conditions or during secondary processing involving heating such as coating and printing, and are excellent in molding processability, and the resin deteriorates due to heat during the molding process. Is less likely to occur.

The refractive index n _{A of the} resin can be adjusted as appropriate depending on the type of monomer used and the polymerization ratio. For example, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] For the hydrogenated adduct of a ring-opening homopolymer of -3-dodecene, 1.51, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene and bicyclo [
2.2.1] 1.51,8-ethylidenetetracyclo [4.4.0.1 ² for hydrogenated ring-opening copolymer with hept-2-ene (composition weight ratio = 9: 1) ^{, 5} . The hydrogenation product of the ring-opening homopolymer of 1 ^7,10 ] -3-dodecene is 1.52 at 25 ° C.

(B) Particles:
The particle (B) used in the present invention may be composed of one component as long as the particle surface is composed of an inorganic or organic polymer component, for example, a composite particle composed of two or more components such as core-shell type particles. But it ’s okay. The outer shape of the particles is not particularly limited, but spherical particles having substantially no corners on the surface are preferable in that the balance between light diffusibility and brightness of the obtained light diffusible molded product is excellent. Among such particles, hollow particles having one or more cavities inside are preferable because the balance between light diffusibility and brightness is further increased.

  The particle (B) used in the present invention has at least one maximum value in each of a region having a particle size of less than 4.0 μm and a region having a particle size of 4.0 μm or more in the volume-based particle size distribution. When particles having such a particle size distribution are used, a molded product having excellent light diffusibility and hardly causing color dispersion in the light guide direction can be obtained.

  The particles (B) having the above particle size distribution can be obtained by mixing particles (B1) having an average particle size of 4.0 μm or more and particles (B2) having a particle size of less than 4.0 μm. The average particle diameter of the particles (B1) is preferably 4.0 μm or more and 10.0 μm or less, more preferably 5.0 μm or more and 8.0 μm or less, and particularly preferably 5.0 μm or more and 7.0 μm or less. The average particle diameter of B2) is preferably 0.2 μm or more and less than 4.0 μm, more preferably 0.3 μm or more and 3.0 μm or less, and particularly preferably 0.7 μm or more and 2.0 μm or less. When the average particle diameter of the particles (B1) and (B2) is in the above range, the particles (B) having the above particle size distribution can be easily obtained. In the present specification, the average particle size of the particles means a particle size in which the integrated value of the frequency is 50% in the volume-based particle size distribution (see Chemical Engineering Handbook 5th edition, page 221).

Further, in the volume-based particle size distribution of the particles (B1), when the peak having the maximum peak area is represented by a lognormal distribution (see Chemical Engineering Handbook 5th edition, page 221), the geometric standard deviation σg _B1 is Preferably, it is 1.0 or more and 2.0 or less, more preferably 1.1 or more and 1.5 or less. In the volume-based particle size distribution of the particles (B2), the peak with the largest peak area is represented by a lognormal distribution. When expressed, the geometric standard deviation σg _B2 is preferably 1.0 or more and 2.0 or less, more preferably 1.1 or more and 1.5 or less. By using the particles (B) having a geometric standard deviation in the above range, a molded product having excellent light diffusibility and hardly causing color dispersion in the light guide direction can be obtained.

The refractive indexes n _B1 and n _B2 of the particles (B1) and (B2) can be appropriately adjusted by changing the type and polymerization ratio of the crosslinkable monomer and other polymerizable monomer described later. In the present invention, the refractive indexes n _B1 and n _B2 are different from the refractive index n _A of the cyclic olefin-based resin (A) in absolute values | n _B1 −n _A |, | n _B2 −n. _A | is preferably 0.04 or more, more preferably 0.04 to 0.9, still more preferably 0.05 to 0.85, and particularly preferably 0.06 to 0.80. The refractive indexes n _A , n _B1 and n _B2 are 2
It is the refractive index of d line | wire measured at 5 degreeC. When | n _B1 −n _A | and | n _B2 −n _A | are in the above ranges, a molded article having excellent light diffusibility and small light reflection can be obtained.

  When at least a part of the particles (B) are hollow particles, the porosity of the hollow particles is preferably 0.01 to 60% by volume, more preferably 0.015 to 55% by volume, and 02 to 50% by volume is particularly preferable. Hollow particles having a porosity in the above range are excellent in light diffusion performance and also excellent in dispersibility in a cyclic olefin resin. The porosity is a value before the hollow particles are dispersed in the cyclic olefin resin (A).

As said particle | grain (B), if it is a particle | grain which has the said characteristic, a well-known inorganic particle, an inorganic hollow particle, an organic particle, or an organic hollow particle can be used. Examples of the inorganic particles and the inorganic hollow particles include inorganic particles such as glass, SiO ₂ , CaCO ₃ , and polyorganosiloxane compounds. Examples of the organic particles and the organic hollow particles include organic crosslinked particles such as acrylic or styrene. Of these particles, organic cross-linked particles are preferable in view of affinity with the cyclic olefin resin (A), molding processability, and the like.

  Specific examples of the organic crosslinked particles include organic hollow particles disclosed in JP-A Nos. 62-127336, 01-315454, 04-126791, and 2002-241448. Is mentioned.

The organic crosslinked particles can also be obtained by polymerizing a crosslinking monomer and another polymerizable monomer as follows.
Examples of the crosslinkable monomer include non-conjugated divinyl compounds such as divinylbenzene; polyvalent acrylate compounds such as trimethylolpropane trimethacrylate and trimethylolpropane triacrylate, and two or more, preferably two copolymerizable double bonds A compound having is preferred.

  Examples of the polyvalent acrylate compound include polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, and polypropylene glycol diacrylate. , 2,2-bis (4-acryloxypropyloxyphenyl) propane, diacrylate compounds such as 2,2-bis (4-acryloxydiethoxyphenyl) propane; trimethylolpropane triacrylate, trimethylolethane triacrylate, Triacrylate compounds such as tetramethylol methane triacrylate; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethyleneglycol Dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol di Dimethacrylate compounds such as methacrylate and 2,2-bis (4-methacryloxydiethoxyphenyl) propane; and trimethacrylate compounds such as trimethylolpropane trimethacrylate and trimethylolethane trimethacrylate.

  Of the crosslinkable monomers, divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are preferred, and divinylbenzene is particularly preferred. Moreover, the said crosslinkable monomer can be used individually or in mixture of 2 or more types.

  Other polymerizable monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, fluorostyrene and vinylpyridine; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; butyl (meth) acrylate, 2-ethylhexyl (meta ) (Meth) acrylates such as acrylate, methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate; unsaturated fatty acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid; acrylamide, methacrylic Examples thereof include amide monomers such as amides.

As a method for forming a cavity in the organic crosslinked particles obtained by polymerizing the crosslinking monomer and other polymerizable monomer, a known method can be adopted. In particular,
(1) A method of preparing organic crosslinked particles containing a foaming agent and then foaming the foaming agent (2) Organic crosslinked particles encapsulating a volatile substance such as butane are prepared, and then the volatile substance is added. 3. Gasification and expansion method (3) A polymer of a crosslinkable monomer and another polymerizable monomer is dissolved, and a gas jet such as air is blown into the polymer to enclose bubbles in the polymer. (4) A method of preparing organic crosslinked particles containing an alkali-swellable substance and then infiltrating the organic crosslinked particles with an alkaline liquid to swell the alkali-swellable substance. (5) Polymethacrylate fine particles. Method of emulsion polymerization of styrene in the presence of seed particles used as seed particles (6) An oil-in-water emulsion is prepared by finely dispersing other polymerizable monomers in water. (7) A two-stage crosslinking method in which organic cross-linked particles are used as seed particles and an incompatible cross-linkable polymer is polymerized and cross-linked on the seed particles. (9) A method of spray-drying organic crosslinked particles, and the like. Among these, Preferably, each method shown by (4)-(9) is used.

  The glass transition temperature (Tg) of the organic hollow particles is preferably 100 ° C. or more from the viewpoint that the heat resistance of the molded product obtained from the resin composition of the present invention is not greatly impaired. In particular, when the resin composition of the present invention is molded at a temperature at which the cyclic olefin resin is heated and melted, such as injection molding or extrusion molding, it is desirable that the organic hollow particles do not melt at the heating and melting temperature of the cyclic olefin resin. Yes. Moreover, when preparing the resin composition of this invention using an organic solvent, it is preferable not to melt | dissolve in this organic solvent.

[Light diffusing resin composition]
The light diffusing resin composition according to the present invention contains the cyclic olefin-based resin (A) and the particles (B), and the content ratio of the particles (B) on a weight basis with respect to the total 100% by weight. 10 to 10,000 ppm, preferably 10 to 2,000 ppm. When the particles (B) are blended in the above range, a molded article having an excellent balance between light diffusibility and light transmittance can be obtained. Further, the particle (B) has an integrated value (b1) of the frequency in the region where the particle size is less than 4.0 μm and an integrated value (b2) of the frequency in the region of 4.0 μm or more in the volume-based particle size distribution. The ratio of b1 and b2 is 100% by volume, and b1 is preferably 10 to 90% by volume, more preferably 20 to 70% by volume. By using the particles (B) in which b1 is in the above range, a molded product having excellent light diffusibility and hardly causing color dispersion in the light guide direction can be obtained.

  The particle (B) having the above particle size distribution is preferably 20 to 90% by weight, more preferably 30 to 80% by weight of the particle (B1), with the total of the particles (B1) and (B2) being 100% by weight. Particularly preferably, it can be easily obtained by mixing in the range of 40 to 75% by weight.

  Further, in the light diffusing resin composition, when hollow particles are used as the particles (B), the inside may be in a hollow state (remains hollow) or may be in a state in which a cyclic olefin-based resin has entered, and is not particularly limited. .

  In addition, the light diffusing resin composition includes, for example, specific hydrocarbon resins described in JP-A-9-221577 and JP-A-10-287732 as long as the effects of the present invention are not impaired. Alternatively, a known thermoplastic resin, thermoplastic elastomer, rubber polymer, organic fine particles, inorganic fine particles and the like may be blended. In addition, 2,6-di-t-butyl-4-methylphenol, 2,2′-dioxy-3,3′-di-t-butyl-5,5′-dimethyldiphenylmethane, tetrakis [methylene-3- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate] known antioxidants such as methane; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, benzyl malonate compounds, etc. The light diffusing resin composition can be stabilized by adding an ultraviolet absorber. Furthermore, additives such as a lubricant can be added for the purpose of improving processability.

The preparation method of the light diffusing resin composition, that is, the blending method of the cyclic olefin resin (A) and the particles (B) is not particularly limited, and can be blended by a known method. For example,
(1) A method of dispersing the particles (B) in a state where the cyclic olefin resin (A) is dissolved in a soluble solvent and removing the solvent by a known method to obtain the resin composition (2) a cyclic olefin Examples thereof include a method of dispersing the particles (B) in a state where the resin (A) is melted.

  In the preparation method of (1) above, as the solution containing the cyclic olefin resin (A), a solution after polymerization, a solution after hydrogenation, a solution after removal of the catalyst, a concentrated solution, a pellet-shaped cyclic olefin resin A solution in which (A) is dissolved can be used.

  The blending method is not particularly limited. For example, a method of mixing using a known stirrer, or a solution containing the cyclic olefin resin (A) and the particles (B) are simultaneously supplied to a known extruder, A method of simultaneously performing solvent removal and dispersion can be mentioned.

  On the other hand, examples of the preparation method (2) include a method using a known single-screw or twin-screw extruder. The cylinder diameter of the extruder is usually 10 to 100 mm. A known screw can be used. For example, in the case of a single shaft, a full flight, a combination of subflights, a dull image incorporated, or a screw whose pitch or groove depth changes in the same screw. It is done. In the case of two shafts, two or three screws, screws rotating in different directions or in the same direction, and screws that can be freely combined with screw parts, the shape of the screw parts is screw, reverse feed screw, paddle type screw, It is possible to freely select from a helical paddle type screw or the like.

  Only one extruder may be used, but a combination of two or more extruders or a combination of continuous and batch kneaders may be used. The raw material may be supplied to the extruder by a plurality of feeders. Moreover, you may supply particle | grains (B) from the middle of an extruder.

  In addition, after the cyclic olefin resin (A) and the particles (B) are mixed in advance in a solid state using a known blender such as a tumbler type or a rotary type, a Henschel mixer, a planetary mixer, or the like. The particles (B) may be dispersed in the cyclic olefin-based resin (A) by supplying to the extruder.

  The cyclic olefin resin (A) or both the cyclic olefin resin (A) and the particles (B) are preferably dried by a known method in advance. Examples of the drying method include hot air drying, dehumidifying drying, vacuum drying, and nitrogen drying. The drying temperature and drying time are not particularly limited, but can usually be arbitrarily set within the range of (Tg-100 ° C.) to (Tg-20 ° C.). Set in the range of 6 hours.

It is also preferable to seal (enclose) the hopper, charging port, vent port, die surface, and the like of the extruder with an inert gas such as nitrogen or argon.
In the light diffusing resin composition according to the present invention, it is preferable that a foreign substance having a size that can be visually discriminated when a light diffusing molded product is molded, preferably 50 μm or more is not present as much as possible. The content of such foreign matters is 5 pieces / 10 g or less, preferably 3 pieces / 10 g or less, and more preferably 0 pieces / 10 g.

The content of the foreign matter can be measured by dissolving the resin composition in a solvent having resin solubility such as toluene and cyclohexane, filtering with a filter, observing with a microscope, and counting the size and number. Alternatively, the cyclic olefin-based resin may be dissolved in the above solvent and filtered with a filter, and then counted using a commercially available fine particle counter based on the principle of light scattering.

  In addition, it is preferable that the light diffusing resin composition according to the present invention removes moisture and oxygen components dissolved by a known method in advance before being subjected to molding processing described later. Even when the light diffusing resin composition is in a solid form such as particles or pellets, it can be dried by a known method. As the drying device, a known drying device such as a hot air dryer, a dehumidifying dryer, a nitrogen circulation dryer, a dehumidification nitrogen circulation dryer, or a vacuum dryer can be used. Among these dryers, it is preferable to use a vacuum dryer or a dryer that circulates an inert gas such as nitrogen because a molded product having hue uniformity can be easily obtained.

  The drying temperature and the drying time are not particularly limited, but can usually be arbitrarily set in the range of Tg-100 ° C to Tg-20 ° C, and the drying time is usually in the range of 2 to 6 hours. Set with.

[Molded product and light guide]
(Molding)
The molded product according to the present invention can be produced by molding the light diffusing resin composition by a known method. The shape of the molded product is not particularly limited, but a flat plate shape is preferable from the viewpoint that the optical characteristics can be sufficiently exhibited, a uniform thickness, a wedge-shaped shape with a continuously changing thickness, a design with a design, etc. Depending on the application, it can be set as appropriate.

  The thickness of the flat molded product is usually 0.2 mm to 5.0 mm, preferably 0.8 mm to 2.2 mm. The size is not particularly limited, and a size employed in a known liquid crystal display device, a transmission screen, or the like can be arbitrarily applied. For example, the size can be widely applied from 1 inch to 40 inches.

  In addition, a known pattern such as a prism, a groove, or a texture may be formed on the surface of the molded product for the purpose of preventing reflection, condensing light, and improving incident light efficiency. These patterns are known methods such as a method of transferring at the time of molding, a method of thermal transfer using a hot stamp after molding, a method of cutting the surface after molding, or a method of printing a thermosetting or ultraviolet curable resin on the surface of the molded product. Can be formed.

  Such a molded article has an excellent balance of brightness, light diffusion performance, and hue uniformity, and is suitably used as an optical component. In particular, it is suitable for an edge light type backlight light guide of a liquid crystal display device. Even when a point light source such as an LED is used for this light guide, there is no local variation in luminance due to generation of bright lines in the vicinity of the light source, and a backlight having a good in-plane luminance balance can be produced.

The molding method of the molded product is not particularly limited, but an injection molding method or an extrusion molding method is preferable.
(1) Injection molding:
The injection molding machine used for injection molding is not particularly defined. For example, the cylinder method is an inline method, the pre-plastic method; the drive method is hydraulic, electric, hybrid; the mold clamping method is direct pressure, and toggle Formula: Examples of the injection direction include a horizontal type and a vertical type. Further, the mold clamping method may be one that can be injection-compressed. Cylinder diameter and clamping force are determined by the shape of the target molded product. Generally, the larger the projected area of the molded product, the larger the clamping force. When the molded product has a large capacity, it is preferable to select a cylinder with a larger cylinder diameter. .

When the cylinder is an in-line type, the screw shape such as compression ratio, length / diameter ratio, subflight presence, etc. can be selected as appropriate, and the screw surface is known such as chromium, titanium, nitride, carbon, etc. It is also possible to apply the coating. It is also possible to provide mechanisms such as screw rotation and pressure control for the purpose of measuring and stability of injection operation. Moreover, it is preferable from a viewpoint that a molded article can be obtained stably to reduce the pressure in the cylinder or the hopper for storing the resin composition, or to seal the cylinder and the hopper with an inert gas such as nitrogen.

  The molded article of the present invention can be manufactured using a mold having a known material or structure. Preferred materials for the mold include ordinary carbon steel, stainless steel, or known alloys based on these, and the surface is quenched, known coating treatment with chromium, titanium, diamond, etc., or nickel Metal plating for pattern processing with a system metal or a copper alloy may be applied.

  In addition, when a pattern is formed on the surface of a molded product for the purpose of collecting light or preventing reflection, a known method such as an electric discharge machine or a cutting machine is formed on the metal coating surface or metal plating surface of the mold or the stamper surface. The pattern may be formed directly by a processing machine, or the pattern may be formed by a method such as electroforming.

At the time of injection molding, it is preferable to apply a method in which the mold cavity is depressurized or an injection compression method in order to reduce warpage of the molded product and stable continuous molding.
When injection molding is performed while the mold cavity is decompressed, the degree of decompression is preferably a gauge pressure of −0.08 MPa or less, more preferably −0.09 MPa or less, and particularly preferably −0.1 MPa or less. If the degree of vacuum exceeds the above range, the degree of vacuum is insufficient, and a molded product having excellent light transmission and light diffusibility may not be obtained.

  The degree of decompression in the above range can be achieved by using a known method, such as a vacuum pump, and it is preferable to use a known sealing material such as an O-ring around the cavity or the ejector mechanism. Vacuum grease or the like may be used as long as impurities are not mixed into the molded product. In addition, the suction port for connecting to a decompression device such as a vacuum pump can be provided at any location in the mold, but is usually provided at the ejector mechanism, the end of the sprue and runner, the nested structure, etc. It is done. In addition, the vacuum suction sequence may be controlled by an electromagnetic valve or the like in conjunction with opening and closing of the mold, or may be operated at all times, or a method that allows the inside of the mold cavity to be at a desired degree of pressure reduction when filling with molten resin. If it is, it will not be restrict | limited.

  When injection molding is performed while reducing the pressure inside the mold cavity, the injection delay time is usually set in order to inject the molten resin with the cavity closed and the pressure reduced. The injection delay time depends on the capacity of the vacuum pump used and the cavity size, but is usually about 0.5 to 3 seconds.

On the other hand, in injection compression molding, the cavity interval is set to 1.5 to 20 times the thickness of the molded product, molten resin is injected into the gap, and the resin pressure measured on the cylinder side is 200 to 2,000 kgf. A method of compressing the surface of the molded product in the mold and narrowing the space between the cavities while holding in the range of / cm ² can be applied.

  In addition, the mold core is set to a movable state by setting it to 1.1 to 10 times the thickness of the molded product, molten resin is injected into the mold core, and after the start of injection or the end of injection, the movable side core is moved to an average speed. A method of compressing at 0.01 mm / sec to 1 mm / sec can also be applied.

These injection compression methods can be performed using a known molding machine.
Other conditions for injection molding are not particularly limited, but the cylinder temperature is usually 260 ° C to 350 ° C, and the mold temperature is usually Tg-1 based on the glass transition temperature Tg of the cyclic olefin resin. C. to Tg-40.degree. C., preferably Tg-5.degree. C. to -25.degree. The injection speed varies depending on the size of the molded product of the present invention and the cylinder size of the molding machine. For example, when the cylinder diameter is 28 mm, a high speed of usually 80 mm / sec or more, preferably 90 to 250 mm / sec is preferable. It is preferable that the holding pressure is appropriately adjusted to the minimum pressure and time that can maintain the shape of the molded product.

(2) Extrusion molding:
As a method of extruding the molded product of the present invention, the light diffusing resin composition is melted with a normal extruder, and this is quantitatively measured with a gear pump, extruded through a die having a slit-like outlet, and sheet By bringing the resin composition stretched into the shape of a film or film into contact with a mirror surface or a surface with a design pattern such as a roll or belt (hereinafter collectively referred to as “roll or the like”), a sheet or film ( Hereinafter, the mirror surface or a specific design shape is transferred to the surface of the sheet, etc.), and after cooling the sheet or the like, it is cut with a cutting machine or wound up with a winder. A method of obtaining a sheet having a predetermined size with a scale is exemplified.

  As a preferred extruder used for extrusion molding, the ratio (L / D) of length (L) to diameter (D) is 28 or more and 40 or less, and the screw diameter is determined by the amount of extrusion, but usually 30 mm to A 125 mm extruder may be mentioned. When L / D is in the above range, a suitable residence time can be obtained, and the resin composition of the present invention can be sufficiently melted. Moreover, when the screw diameter is less than 30 mm, the measurement is not stable, and the productivity may be lowered, which is not preferable. Moreover, since it will become easy to retain a raw material after measurement when it exceeds 125 mm, it is not preferable.

  It is also preferable to use a gear pump in order to achieve film thickness stability of the sheet or the like. A well-known gear pump can be used as the gear pump, but an external lubrication system that discharges the resin used for lubrication is particularly preferably used.

  As the die for stretching the resin composition of the present invention into a film shape, a T die is preferably used, and examples thereof include a coat hanger die and a fish tail die, and a coat hanger die is particularly preferable. The shape of the manifold is not particularly limited, but a manifold with a small retention is preferable. Further, the tip of the T die is preferably a sharp edge, and if there is a defect in the edge, it may cause a die line, which is not preferable. In particular, edge treatment in which a carbide coating such as tungsten-carbide is applied by a technique such as thermal spraying is convenient for preventing die lines.

When transferring from a T die to a roll or the like, it is preferable to transfer the T die and the roll as close as possible, and the distance is preferably 50 mm or less.
When producing a smooth sheet or the like, the roll or the like used for transfer is preferably polished in a mirror shape, and the surface polishing state is a surface roughness with a maximum roughness of 0.1 μm (0.1 s). It is preferable that When the maximum roughness exceeds the above range, the roughness of the surface of the roll or the like is transferred to the surface of the sheet or the like, which may be a defect in the appearance of the sheet or the like. The material used for the rolls and the like is preferably iron, stainless steel, iron subjected to hard chrome plating, or the like. In order to improve releasability, it is also preferable to treat iron or stainless steel with a metal oxide such as aluminum oxide or chromium oxide or a hard metal such as tungsten or tungsten carbide by thermal spraying or the like.

In the present invention, a three-dimensional pattern may be formed on a roll or the like, and the three-dimensional pattern may be transferred to at least one surface of a sheet or the like.
The three-dimensional pattern is not particularly limited. For example, a prism shape, semicircular shape, elliptical shape, rectangular shape, V-shaped groove or mountain shape, hemispherical shape, semielliptical shape, conical shape, polygonal pyramid shape. Shape, truncated cone shape, polygonal frustum shape, and other convex or concave shapes, random uneven shapes, lattice shapes, branched groove shapes, and other arbitrary pattern shapes. These functions are not particularly limited, but those that provide optical functions such as light collection, scattering, diffraction, and polarization are preferably used.

  A method for forming a three-dimensional pattern on a roll or the like is not particularly limited, and a known method can be applied. For example, a cutting method, a method by electric discharge machining, a laser machining, a method by electroforming, a method by etching, a method of printing a curable resin, a method by sandblasting, and the like can be mentioned.

  The three-dimensional pattern can be formed by directly processing a substrate such as a roll, and the substrate such as a roll is plated with a known metal such as nickel or copper or a compound thereof, and further photocured. It is also possible to process these after applying an organic or thermosetting organic compound. Further, it is possible to produce a stamper and make a multilayer with a metal endless belt or a metal roll.

  When the obtained sheet or the like is peeled from a roll or the like, it is preferable to take off the film while controlling the peeling force with a tension meter or the like. The peeling force is preferably weak enough that the film does not bend or break.

  As a specific transfer method, an air knife method in which a roll is used on one side and a sheet or the like is pressure-bonded to the roll or the like with air or nitrogen pressure from the opposite side of the roll; There are a method of attaching a sheet or the like to a roll or the like with a sufficient force; a method of mechanically contacting a presser roll or the like. Of these transfer methods, the method using the presser roll is preferable in that air can be prevented from entering between the roll and the sheet and the risk of occurrence of wrinkles can be eliminated.

(Light guide)
As described above, the molded article of the present invention is suitable as a light guide used as a light source device such as a backlight of a liquid crystal display device or a front light, and particularly suitable as a light guide for an edge light type backlight. is there. When the molded product of the present invention, for example, the light guide is incident from the end face using a point light source such as an LED, there is no local brightness variation due to the generation of bright lines in the vicinity of the light source, and the in-plane brightness balance. A light source device for a good liquid crystal display device, for example, a backlight can be manufactured.

  In addition, the light guide of the present invention can be laminated with a known film for the purpose of improving the brightness and uniforming the brightness, and it is also possible to prevent reflection, antistatic, damage, etc. on the surface of the light guide. For the purpose, a wet or dry coating can be applied.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example. In the following, “parts” and “%” are “parts by weight” and “% by weight” unless otherwise specified.

Various physical properties were measured by the following methods.
(Intrinsic viscosity: η _inh )
A sample having a polymer concentration of 0.5 g / dl was prepared using chloroform as a solvent, and measured with an Ubbelohde viscometer at 30 ° C.

(Molecular weight)
Using Tosoh Corporation HLC-8020 gel permeation chromatography (GPC, column: 4 series of TSKgel G7000HXL × 1, TSKgel GMHXL × 2 and TSKgel G2000HXL × 1 manufactured by Tosoh Corporation) with tetrahydrofuran (THF) solvent Measurements were made to determine polystyrene-converted weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn). In addition, Mn represents the number average molecular weight of polystyrene conversion.

(Glass transition temperature: Tg)
Using a DSC6200 manufactured by Seiko Instruments Inc., the temperature was increased at a rate of temperature increase of 20 ° C./min under a nitrogen stream.

(Refractive index)
For cyclic olefin resin:
A flat plate (40 mm × 60 mm × 3.2 mm) of a cyclic olefin resin was prepared by injection molding, and annealed at (Tg + 5) ° C. for 30 minutes. Then, after being left for one week in an environment of 25 ° C. and 50 RH%, the refractive index of d-line was measured using a refractometer (PR-2 manufactured by Carl Zeiss Jena Co.) under the conditions of 25 ° C. and 50 RH%. .
For crosslinked particles:
The crosslinked particles are filtered through a 60-mesh wire mesh, and a refractive index standard solution (manufactured by Cargille) is added dropwise to the filter cake and mixed, and then observed with an optical microscope. The rate was taken as the refractive index value of the crosslinked particles. The measurement was performed at 25 ° C.

(Particle size at which the particle size distribution reaches a maximum)
The particle size distribution was measured by a light scattering method using a particle size distribution measuring device (Microtrack UAP150 manufactured by Nikkiso Co., Ltd.). In the obtained particle size distribution curve, the particle diameter at which the frequency is maximized was determined.

(Average particle size)
The particle size distribution was measured by a light scattering method using a particle size distribution measuring device (Microtrack UAP150 manufactured by Nikkiso Co., Ltd.). The obtained particle size distribution was plotted on logarithmic probability paper, and the particle size at which accumulation was 50% on the volume basis was defined as the average particle size.

(Porosity)
The porosity was calculated by observing the cross section of the particles with a scanning electron microscope and processing the image.
(A) In the case of hollow particles comprising a single hole The outer diameter of the particle was d1, the outer diameter of the hollow portion was d2, and the porosity was calculated by the following equation.

Porosity = (d2 / d1) ³ × 100
(B) In the case of hollow particles composed of a plurality of holes When image analysis of the cross section of the particle is performed, the area A occupied by the hollow part is calculated, and the plurality of holes are regarded as a single hole by the following equation The equivalent diameter d3 was calculated.

d3 = (4A / π) ^1/2
The porosity was calculated from the assumed equivalent diameter d3 and the outer diameter d1 by the following equation.
Porosity = (d3 / d1) ³ × 100
<Synthesis of cyclic olefin resin>
[Synthesis Example 1]
As a cyclic olefin, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0
. 1 ^2,5 . 1 ^7,10 ] -3-dodecene 250 parts, 1-hexene 41 parts as a molecular weight regulator, and 750 parts toluene as a ring-opening polymerization reaction solvent were charged into a reaction vessel purged with nitrogen. Heated. Next, 0.62 parts of a toluene solution of triethylaluminum (concentration: 1.5 mol / L) and tungsten hexachloride modified with t-butanol / methanol (t-butanol: methanol: tungsten) were added to the solution in the reaction vessel. .35 mol: 0.3 mol: 1 mol) of a toluene solution (concentration 0.05 mol / L) 3.7 parts was added, and this solution was heated and stirred at 80 ° C. for 3 hours to effect ring-opening polymerization reaction. To obtain a solution containing a ring-opening polymer.

The polymerization conversion rate in this polymerization reaction was 97%.
The autoclave was charged with 4,000 parts of the ring-opening polymer solution thus obtained, and 0.48 part of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution. Then, hydrogenation reaction was carried out by heating and stirring for 3 hours under the conditions of a hydrogen gas pressure of 100 kg / cm ² and a reaction temperature of 165 ° C. After cooling the obtained reaction solution (solution containing a hydrogenated polymer), the hydrogen gas was released.

Subsequently, this reaction solution was poured into a large amount of methanol to coagulate the hydrogenated polymer and collect it.
Thereafter, the recovered hydrogenated polymer is dissolved in toluene to prepare a solution having a concentration of 20%, filtered through a filter having a pore size of 1 μm, and then poured again into a large amount of methanol to coagulate and recover the hydrogenated polymer. did. This re-dissolution / precipitation / recovery operation was repeated three times, and the finally obtained hydrogenated polymer was dried at 100 ° C. under reduced pressure for 12 hours and then granulated using a melt extruder to prepare pellets. .

The hydrogenation rate of the hydrogenated polymer thus obtained (hereinafter referred to as “cyclic olefin resin A1”) was measured by ¹ H-NMR under the condition of 400 MHz.
It was 00%.

The refractive index of cyclic olefin-based resin A1 at 28 ° C. is 1.51, and η _inh is 0.5.
2, Mw was 75,000, Mw / Mn was 3.5, and Tg was 164 ° C.
[Synthesis Example 2]
As a cyclic olefin, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . Synthesis Example 1 except that 225 parts of 1 ^7,10 ] -3-dodecene and 25 parts of bicyclo [2.2.1] hept-2-ene were used and 43 parts of 1-hexene was used as a molecular weight regulator. In the same manner as above, a hydrogenated polymer was obtained. The hydrogenation rate of the obtained hydrogenated polymer (hereinafter referred to as “cyclic olefin resin A2”) was substantially 100%.

The refractive index of cyclic olefin resin A2 at 28 ° C. is 1.51, η _inh is 0.50, M
w was 62,000, Mw / Mn was 3.5, and Tg was 141 ° C.
[Synthesis Example 3]
As a cyclic olefin, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] −
A hydrogenated polymer was obtained in the same manner as in Synthesis Example 1 except that 250 parts of 3-dodecene and 750 parts of cyclohexane were used as a solvent for the ring-opening polymerization reaction. The hydrogenation rate of the obtained hydrogenated polymer (hereinafter referred to as “cyclic olefin resin A3”) was substantially 100%.

The refractive index of cyclic olefin resin A3 at 28 ° C. is 1.52, η _inh is 0.50, M
w was 65,000, Mw / Mn was 3.0, and Tg was 145 ° C.
<Preparation of crosslinked particles>
[Preparation Example 1]
98 parts of styrene, 2 parts of methacrylic acid, 10 parts of t-dodecyl mercaptan, 0.05 part of sodium dodecylbenzenesulfonate, 0.4 part of potassium peroxide, and 200 parts of water are placed in a 2 liter flask and stirred with nitrogen. The temperature was raised to 70 ° C. in a gas and polymerization was carried out for 6 hours. Thereby, seed polymer particles having a polymerization yield of 98% and an average particle size of 0.31 μm were obtained.

  Next, 3 parts of the obtained seed polymer particles, 10 parts of polyvinyl alcohol, 0.05 part of hydroquinone, 500 parts of water, 1 part of benzoyl peroxide, 50 parts of divinylbenzene (purity 55%), and 5 parts of cyclohexanol were reacted in a reactor. The mixture was stirred for 30 minutes, heated to 70 ° C. and polymerized for 4 hours to obtain crosslinked particles. Thereafter, a 1% aluminum sulfate aqueous solution was added to the dispersion of the crosslinked particles, followed by filtration, and sufficient washing to remove cyclohexanol, followed by drying under reduced pressure to obtain powdered crosslinked particles B2-1.

  The particle size distribution of the crosslinked particles B2-1 was plotted on log-normally established paper, and it was confirmed that the log-normal distribution was followed. The average particle size (particle size at which the integrated value of frequency is 50% on a volume basis) was 3.3 μm, the geometric standard deviation was 1.2, and the hollow particles had a porosity of 48%. Further, the refractive index of this crosslinked particle B2-1 at 25 ° C. was 1.59.

[Preparation Example 2]
Powdered crosslinked particles B2-2 were obtained in the same manner as in Preparation Example 1, except that the amount of seed polymer particles added was changed to 7 parts. The particle size distribution of the crosslinked particles B2-2 was plotted on log-normally established paper, and it was confirmed that the log-normal distribution was followed. The average particle size (particle size at which the integrated value of frequency is 50% on a volume basis) was 0.8 μm, the geometric standard deviation was 1.2, and the hollow particles had a porosity of 47%. Further, this crosslinked particle B2-2 had a refractive index of 1.59 at 25 ° C.

[Preparation Example 3]
Crosslinked particles B2-3 were obtained in the same manner as in Preparation Example 1, except that 5 parts of divinylbenzene and 45 parts of styrene were used instead of 50 parts of divinylbenzene. The particle size distribution of the crosslinked particles B2-3 was plotted on log-normally established paper, and it was confirmed that the log-normal distribution was followed. The average particle size (particle size with an integrated frequency of 50% on a volume basis) was 3.3 μm and the geometric standard deviation was 1.2, but no pores were observed (the porosity was 0%). . Further, the refractive index at 25 ° C. of the crosslinked particles B2-3 was 1.59.

[Preparation Example 4]
Crosslinked particles B2-4 were obtained in the same manner as in Preparation Example 2, except that 5 parts of divinylbenzene and 45 parts of styrene were used instead of 50 parts of divinylbenzene. The particle size distribution of the crosslinked particles B2-4 was plotted on log-normally established paper, and it was confirmed that the log-normal distribution was followed. The average particle size (particle size where the integrated value of the frequency shows 50% on a volume basis) was 0.8 μm and the geometric standard deviation was 1.2, but no pores were observed (the porosity was 0%). . Further, the refractive index at 25 ° C. of the crosslinked particles B2-4 was 1.59.

[Crosslinked particles B1]
As the crosslinked particles B1-1, Rohm and Haas particles (trade name: PERLOID EXL-5136) were used. The particle size distribution of the crosslinked particles B1-1 was plotted on lognormally established paper, and it was confirmed that the logarithmic normal distribution was followed. The average particle diameter (particle diameter at which the integrated value of the frequency is 50% on a volume basis) was 5.0 μm, the geometric standard deviation was 1.2, and the refractive index at 25 ° C. was 1.46.

[Examples 1-7, Comparative Examples 1-9]
<Manufacture of resin composition>
The particles having the combinations shown in Table 1 were mixed, the particle size distribution of the particles after mixing was measured, and the particle size at which the frequency was maximized was determined. Next, the cyclic olefin resin was vacuum dried at 100 ° C. for 4 hours in advance. Thereafter, the cyclic olefin-based resin and the particles were premixed with a tumbler-type blender at the ratio shown in Table 1.

  A twin-screw extruder (TEM-37BS, manufactured by Toshiba Machine Co., Ltd.) was heated to a temperature in the range of 290 ° C to 300 ° C, and the hopper and the cylinder were filled with nitrogen. After the temperature is stabilized, the screw is rotated at 100 rpm, and nitrogen is allowed to flow into the hopper, while a premixed mixture of cyclic olefin resin and crosslinked particles is supplied at a rate of 20 kg / hr to perform melt mixing, and light diffusibility A resin composition was obtained.

The obtained light diffusing resin composition was vacuum-dried at 100 ° C. for 4 hours, and then stored in an aluminum bag filled with nitrogen.
<Injection molding 1>
Injection using a mold cavity (1) (both mirror plates of 80 mm x 60 mm, 1 mm thickness) with an injection molding machine (SG75M-S, manufactured by Sumitomo Heavy Industries, Ltd., cylinder diameter 28 mm, mold clamping 75 tons) Molded. The injection molding speed was 100 mm / sec, the cylinder temperature was a temperature in the range of Tg + 140 ° C. to Tg + 160 ° C. of the resin, and the mold temperature was a temperature in the range of Tg−20 ° C. to Tg−10 ° C. of the resin. Hereinafter, the injection molded product produced here is referred to as a “molded body”.

<Injection molding 2>
Instead of the mold cavity (1), a mold cavity (2) having a pattern of 60 mm × 40 mm, thickness 0.8 mm, having a mirror surface on one side and a pitch of 250 μm and a depth of 10 μm on the other side is used. Except that, injection molding was performed in the same manner as the injection molding 1 described above. Hereinafter, the injection molded product produced here is referred to as “light guide”.

The obtained molded body and light guide were evaluated by the following methods.
(Total light transmittance and haze)
About the molded object, the total light transmittance was measured based on JIS K7361-1 and the haze was measured based on JIS K7136 using Murakami Color Research Laboratory haze and transmittance meter HM-150.

(Wavelength dependence of light transmittance)
About the molded object, the light transmittance was measured according to wavelength using the spectrophotometer (H-3310 by Hitachi, Ltd.). The ratio of the light transmittance at a wavelength of 400 nm to the light transmittance at a wavelength of 700 nm was calculated by the following formula, and the wavelength dependency of the light transmittance was evaluated. The closer this value is to 1.00, the lower the wavelength dependency of the light transmittance.

Wavelength dependence of light transmittance = (light transmittance at 400 nm) / (light transmittance at 700 nm)
(Emission line due to light source)
Light enters the light guide using three LED light sources (Nichia's NSSW008B) arranged at an 8 mm pitch on the light entrance surface of the light guide, and is opacity up to 2.8 mm from the light entrance surface. Covered with film and allowed to emit light. In this state, the bright line derived from the light source in the light emitting surface of the light guide was visually observed and evaluated according to the following criteria. Most preferably, the evaluation is A.
A No bright line was observed.
B A weak emission line was observed.
C A clear emission line was observed.

(Hue uniformity)
Using three LED light sources (NSSW008B manufactured by Nichia Chemical Co., Ltd.) arranged at 8 mm pitch on the light incident surface of the light guide, the light is incident on the light guide, and the light transmittance is 2.8 mm from the light incident surface. Covered with film and allowed to emit light. Further, the light-emitting surface is equally divided into seven vertical and horizontal areas with a rectangular area, and the chromaticity x, y for a total of 49 regions are measured using a color difference meter (LC-100, manufactured by Konica Minolta), and the obtained chromaticity x, Yellowness YI was calculated from y. The standard deviation of the 49 YI values obtained was calculated, and the hue uniformity was evaluated based on that value. A smaller standard deviation indicates a more uniform hue on the light emitting surface.

(Brightness uniformity)
Using three LED light sources (NSSW008B manufactured by Nichia Chemical Co., Ltd.) arranged at 8 mm pitch on the light incident surface of the light guide, the light is incident on the light guide, and the light transmittance is 2.8 mm from the light incident surface. Covered with film and allowed to emit light. The luminance [L (20)] at 20 mm from the end and the luminance [L (50)] at 50 mm from the end are measured along the center line of the light incident surface, and the ratio of these luminances = L (50) / L (20) was calculated. The closer this value is to 1, the less the light is attenuated inside the light guide, meaning that the luminance within the light emitting surface is more uniform.

  The results are shown in Table 1.

  The molded bodies and light guides of Examples 1 to 7 have the same wavelength dependency, hue uniformity, and luminance uniformity of light transmittance as compared with the molded body and light guide of Comparative Example 1 that do not contain particles. However, it can be seen that it is excellent in that the bright line originating from the light source can be eliminated.

Moreover, compared with the molded object and light guide of Comparative Examples 2 and 4 in which the molded object and light guide of Examples 1-7 contain only a particle | grain with an average particle diameter of 3.3 micrometers, the wavelength dependence of the light transmittance. It can be seen that the brightness and the hue uniformity are the same, but the brightness uniformity is excellent, and the bright line originating from the light source can be erased more sufficiently. Moreover, it is equivalent in that the bright line derived from the light source can be sufficiently erased as compared with the molded body and the light guide of Comparative Examples 3 and 5 containing only particles having an average particle diameter of 0.8 μm. It can be seen that the wavelength dependency, hue uniformity, and luminance uniformity are excellent. Furthermore, the wavelength dependency, hue uniformity and luminance uniformity of the light transmittance are the same as those of the molded body and the light guide of Comparative Example 6 containing only particles having an average particle diameter of 6.0 μm. It turns out that it is excellent at the point which can eliminate the bright line caused.

  Furthermore, the molded bodies and light guides of Examples 1 to 7 were derived from the light source as compared with the molded bodies and light guides of Comparative Examples 7 and 8 containing only two types of particles having an average particle diameter of less than 4.0 μm. It is the same in that the bright line can be sufficiently erased, but it is understood that the light transmittance is excellent in wavelength dependency, hue uniformity and luminance uniformity.

  Further, when Examples 1 to 7 and Comparative Example 9 are compared, even when particles having an average particle diameter of less than 4.0 μm and particles having an average particle diameter of 4.0 μm or more are combined, the amount of these added is remarkably high. When the number is large (Comparative Example 9), the bright line originating from the light source can be erased, but it can be seen that the wavelength dependence, hue uniformity, and luminance uniformity of the light transmittance are reduced.

  As described above, by combining two kinds of particles having an average particle diameter in a specific range, the light transmittance may be reduced depending on the wavelength, or the uniformity of hue and luminance may be reduced due to light scattering by the particles. In other words, the bright line originating from the light source can be sufficiently erased.

  The molded article produced from the light diffusing resin composition of the present invention is useful as a light guide for an edge light type backlight of a liquid crystal display device.

Claims (8)

The cyclic olefin-based resin (A) and the particles (B) are contained, and the content of the particles (B) is 10 to 10,000 ppm on a weight basis with respect to a total of 100 wt% of these,
The light diffusing resin, wherein the particle (B) has at least one maximum value in each of a region having a particle diameter of less than 4.0 μm and a region having a particle diameter of 4.0 μm or more in a volume-based particle size distribution. Composition.   The particles (B) are obtained by mixing particles (B1) having a volume-based average particle size of 4.0 μm or more and particles (B2) having an average particle size of less than 4.0 μm. The light diffusing resin composition according to claim 1. In the volume-based particle size distribution of the particles (B1), when the peak having the largest peak area is represented by a lognormal distribution, the geometric standard deviation σg _B1 is 1.0 or more and 2.0 or less,
In the volume-based particle size distribution of the particles (B2), the geometric standard deviation σg _B2 is 1.0 or more and 2.0 or less when the peak having the largest peak area is represented by a lognormal distribution. The light diffusing resin composition according to claim 2. Absolute value of the difference between the refractive index n _B1 of the refractive index n _A and the particles (B1) of the cycloolefin resin (A) | is not less than 0.04, | n _B1 -n _A
Claims, characterized in that it is 0.04 or more | absolute value of the difference between the refractive index n _B2 of the refractive index n _A and the particles (B2) of the cycloolefin resin _(A) | n _B2 -n A Item 4. The light diffusing resin composition according to Item 2 or 3.   The light diffusing resin composition according to claim 1, wherein at least a part of the particles (B) are hollow particles.   The light diffusing resin composition according to claim 1, wherein at least a part of the particles (B) are organic crosslinked particles.   A molded article formed by injection molding the light diffusing resin composition according to any one of claims 1 to 6.   A light guide for an edge light type backlight of a liquid crystal display device, which is formed by injection molding the light diffusing resin composition according to claim 1.