JP2010235815A - Liquid curable resin composition - Google Patents

Abstract

A liquid curable resin composition having good storage stability of a resin liquid and having a hardness (Young's modulus) suitable as a secondary material is provided.
[Solution]
(A1) Urethane (meth) acrylate having a structure represented by the following formula (1),
^{H-I-POL 1 -I-} H (1)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, and POL ¹ is an aliphatic polyether polyol having a number average molecular weight of 500 to 4,000. ]
(A2) urethane (meth) acrylate represented by the following formula (2),
HIH (2)
[In the above formula, two H are the same hydroxyl group-containing (meth) acrylate, and I is a polyisocyanate. ]
(A3) urethane (meth) acrylate represented by the following formula (3),
H ¹ -I-H ² (3)
[In the above formula, H ¹ and H ² are different hydroxyl group-containing (meth) acrylates, and I is a polyisocyanate. ]
(B) an alkyl (meth) acrylate represented by the following formula (5),
^{_{CH 2 = C (R 1)}} COO- (CH 2) n -CH (CH 3) 2 (5)
(R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 4 to 8)
And (C) a liquid curable resin composition for a secondary material of an optical fiber containing a polymerization initiator.
[Selection figure] None

Description

  The present invention relates to a liquid curable resin composition that provides a cured product having a high stress relaxation rate and a sufficient Young's modulus.

  An optical fiber is manufactured by coating a glass fiber obtained by hot-melt spinning of glass with a resin for the purpose of protection and reinforcement. As this resin coating, a flexible primary coating layer (hereinafter also referred to as “primary coating layer”) is first provided on the surface of the optical fiber, and a highly rigid secondary coating layer (hereinafter also referred to as “primary coating layer”) is provided. Hereinafter, a structure provided with “secondary coating layer” is also known. Tape-like optical fibers and optical fiber cables in which a plurality of optical fiber strands coated with these resins are hardened with a binding material are also well known. A resin composition for forming a primary coating layer of an optical fiber strand is a primary material, a resin composition for forming a secondary coating layer is a secondary material, and a binding material for a plurality of optical fiber strands The resin composition used as is called a bundling material. In some cases, a plurality of tape-like optical fibers and optical fiber cables may be further combined with a binding material, and the binding material used at this time is also called a bundling material. As these resin coating methods, a method in which a liquid curable resin composition is applied and cured by heat or light, particularly ultraviolet rays, is widely used.

  In such an optical fiber, it is required to reduce the diameter or the coating thickness in order to realize a multi-core optical fiber cable, etc., but it is difficult to realize these without degrading the optical fiber strength. there were. As a coated optical fiber with a thin coating, while maintaining optical transmission characteristics and opportunity characteristics, it has a specific stress relaxation time (Patent Document 1) and a stress relaxation property using a specific radical curable compound. A radiation curable composition (Patent Document 2) that gives an excellent cured product has been proposed.

  However, in these hardened | cured materials etc., stress relaxation time could not be shortened enough and problems, such as thinning of coating | cover, were not able to be solved. Moreover, the liquid curable resin composition for secondary materials of the optical fiber excellent in the high-speed coating property by employ | adopting the acrylate monomer which has a linear alkyl group is also known (patent document 3).

JP-A-8-5877 Japanese Patent Laid-Open No. 2001-31731 Japanese Patent Laid-Open No. 2005-255955

However, in the case of a secondary material that employs an acrylate monomer having a linear alkyl group, the crystallinity in the composition is high due to the structural reason of the monomer, particularly when the composition is placed in a low-temperature environment. In some cases, the storage stability of the resin liquid was lowered.
Accordingly, an object of the present invention is to provide a liquid curable resin composition having good storage stability of a resin liquid, particularly storage stability in a low temperature environment, and having a hardness (Young's modulus) suitable as a secondary material. There is.

  As a result of various studies to obtain a composition having the above characteristics, the present inventors solved these problems by combining a mixture of urethane (meth) acrylates having a specific structure and an acrylate monomer having a specific branched structure. The present invention has been completed by finding out what can be done.

That is, the present invention includes the following components (A1), (A2), (A3), (B) and (C):
(A1) Urethane (meth) acrylate having a structure represented by the following formula (1),
^{H-I-POL 1 -I-} H (1)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, and POL ¹ is an aliphatic polyether polyol having a number average molecular weight of 500 to 4,000. ]
(A2) urethane (meth) acrylate represented by the following formula (2),
HIH (2)
[In the above formula, two H are the same hydroxyl group-containing (meth) acrylate, and I is a polyisocyanate. ]
(A3) urethane (meth) acrylate represented by the following formula (3),
H ¹ -I-H ² (3)
[In the above formula, H ¹ and H ² are different hydroxyl group-containing (meth) acrylates, and I is a polyisocyanate. ]
(B) an alkyl (meth) acrylate represented by the following formula (5),
^{_{CH 2 = C (R 1)}} COO- (CH 2) n -CH (CH 3) 2 (5)
(R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 4 to 8)
(C) A liquid curable resin composition for a secondary material of an optical fiber containing a polymerization initiator, and a secondary coating layer for an optical fiber obtained by curing the liquid curable resin composition.

  The liquid curable resin composition of the present invention has good storage stability, particularly when the composition is placed in a low-temperature environment, the storage stability of the resin liquid is good, and the composition has a viscosity suitable for high-speed coating properties. ing. Moreover, it has hardness (Young's modulus) suitable as a secondary material. Therefore, the composition of the present invention is useful as an optical fiber coating material, particularly as a secondary material.

Below, the liquid curable resin composition of this invention is demonstrated in detail.
The urethane (meth) acrylate which is a polymerizable oligomer of the component (A) used in the liquid curable resin composition of the present invention is a mixture containing the following components (A1), (A2) and (A3), and (A4) A component can also be contained.
The urethane (meth) acrylate of component (A) used in the present invention is synthesized from a polyol compound and a diisocyanate compound and a hydroxyl group-containing (meth) acrylate, or from a diisocyanate compound and a hydroxyl group-containing (meth) acrylate. That is, it is produced by reacting the isocyanate group of the diisocyanate with the hydroxyl group of the polyol compound and / or the hydroxyl group of the hydroxyl group-containing (meth) acrylate.

The urethane (meth) acrylate as the component (A1) has a structure represented by the following formula (1).
^{H-I-POL 1 -I-} H (1)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, and POL ¹ is an aliphatic polyether polyol having a number average molecular weight of 500 to 4,000. ]
The component (A1) can be obtained by reacting an aliphatic polyether polyol having a number average molecular weight of 500 to 4,000, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate.

  The number average molecular weight of the aliphatic polyether polyol used for the component (A1) is preferably 500 to 2,000, and more preferably 700 to 1,500. In general, since aliphatic polyether polyol has a flexible structure, the Young's modulus of the cured product decreases as the molecular weight increases, and the Young's modulus of the cured product increases as the molecular weight decreases. Therefore, the Young's modulus suitable as a secondary material can be obtained by setting it as the said molecular weight range. Here, the molecular weight of the aliphatic polyether polyol is a polystyrene-equivalent number average molecular weight measured by a gel permeation chromatography method.

The urethane (meth) acrylate as the component (A2) has a structure represented by the following formula (2).
HIH (2)
[In the above formula, two H are the same hydroxyl group-containing (meth) acrylate, and I is a polyisocyanate. ]
The component (A2) can be obtained by reacting 2 mol of one kind of hydroxyl group-containing (meth) acrylate with 1 mol of diisocyanate (divalent polyisocyanate).
Since the urethane (meth) acrylate of component (A2) does not have a structural unit derived from polyol, it has a rigid structure compared to component (A1). For this reason, Young's modulus suitable as a secondary material can be obtained by containing (A2) component in addition to (A1) component.

The urethane (meth) acrylate as the component (A3) has a structure represented by the following formula (3).
H ¹ -I-H ² (3)
[In the above formula, H ¹ and H ² are different hydroxyl group-containing (meth) acrylates, and I is a polyisocyanate. ]
Component (A3) can be obtained by reacting two different hydroxyl group-containing (meth) acrylates and 1 mol of diisocyanate in equimolar amounts.
The component (A3) has a structure derived from two different hydroxyl group-containing (meth) acrylates, in addition to being a urethane (meth) acrylate having a rigid structure similar to (A2). The crystallinity in the product is low, and the storage stability of the composition can be improved.

Furthermore, as a component (A), the urethane (meth) acrylate of a component (A4) can be mix | blended. The urethane (meth) acrylate as the component (A3) has a structure represented by the following formula (4).
^{H-I-POL 2 -I-} H (4)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, POL ² is an aliphatic polyether polyol having a number average molecular weight exceeding 4,000 but not exceeding 12,000. is there. ]
The component (A4) can be obtained by reacting an aliphatic polyether polyol having a number average molecular weight exceeding 4,000 and not more than 12,000, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate.

  The number average molecular weight of the aliphatic polyether polyol used for the component (A4) is preferably 6,000 to 10,000, and more preferably 8,000 to 10,000. By adding urethane (meth) acrylate having a structural unit derived from an aliphatic polyether polyol having a higher molecular weight than component (A1), the surface property of the secondary coating layer, which is a cured product, is improved, and bobbin It is possible to improve the unevenness of the winding of the optical fiber to the like.

Examples of the diisocyanate compound used for the production of the urethane (meth) acrylate (A1), (A2), (A3), and (A4) include aromatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates. Examples of aromatic diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, and m-phenylene diisocyanate. P-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylene diisocyanate, bis (2- Isocyanate) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, tetramethylxylylene diisocyanate and the like. Examples of the alicyclic diisocyanate include isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and 2,5-bis (isocyanate methyl) -bicyclo [2.2.1] heptane. 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane and the like. Examples of the aliphatic diisocyanate include 1,6-hexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. Of these, 2,4-tolylene diisocyanate and isophorone diisocyanate are particularly preferred.
These diisocyanate compounds may be used alone or in combination of two or more.

  As the hydroxyl group-containing (meth) acrylate compound used for the production of urethane (meth) acrylate (A1), (A2), (A3), (A4), a hydroxyl group-containing (meth) having a hydroxyl group bonded to a primary carbon atom. It is preferable to use an acrylate (referred to as a primary hydroxyl group-containing (meth) acrylate) or a hydroxyl group-containing (meth) acrylate (referred to as a secondary hydroxyl group-containing (meth) acrylate) in which the hydroxyl group is bonded to a secondary carbon atom. A hydroxyl group-containing (meth) acrylate having a hydroxyl group bonded to a tertiary carbon atom (referred to as a tertiary hydroxyl group-containing (meth) acrylate) is not preferred because it has poor reactivity with an isocyanate group.

  Examples of the primary hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, and trimethylolethane di (meth) acrylate.

  As the secondary hydroxyl group-containing (meth) acrylate, for example, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meta) ) Acrylates and the like, and compounds obtained by addition reaction of glycidyl group-containing compounds such as alkyl glycidyl ethers, allyl glycidyl ethers and glycidyl (meth) acrylates with (meth) acrylic acid.

  Examples of the aliphatic polyether polyol used in the production of the urethane (meth) acrylate (A1), (A2), (A3), and (A4) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, Examples thereof include polyether diol obtained by ring-opening copolymerization of polyheptamethylene glycol, polydecamethylene glycol and two or more ion-polymerizable cyclic compounds.

  Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, and tetraoxane. , Cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, glycidyl benzoate And cyclic ethers.

  Specific examples of polyether diols obtained by ring-opening copolymerization of two or more of the above ion-polymerizable cyclic compounds include, for example, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and the like. Binary copolymers obtained from combinations of ethylene oxide, propylene oxide and ethylene oxide, butene-1-oxide and ethylene oxide; terpolymers obtained from combinations of tetrahydrofuran, butene-1-oxide and ethylene oxide .

  Examples of the aliphatic polyether diol include PTMG650, PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical Corporation), PPG400, PPG1000, PPG2000, PPG3000, EXCENOL720, 1020, 2020 (above, manufactured by Asahi Glass Urethane Co., Ltd.), PEG1000, Unisafe DC1100, DC1800 (above, manufactured by NOF Corporation), PPTG2000, PPTG1000, PTG400, PTGL2000 (above, manufactured by Hodogaya Chemical Co., Ltd.), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B, EO / BO4000, EO / It can also be obtained as a commercial product such as BO3000, EO / BO2000, EO / BO1000, EO / BO500 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

  In the production of urethane (meth) acrylate (A), copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, triethylamine, 1,4-diazabicyclo [2.2.2] octane, 2,6,7 -It is preferable to use 0.01 to 1 mass% of the urethanization catalyst selected from trimethyl-1,4-diazabicyclo [2.2.2] octane and the like with respect to the total amount of the reaction product. The reaction temperature is usually 5 to 90 ° C, particularly 10 to 80 ° C.

  The preferred molecular weight of the urethane (meth) acrylate (A) used in the present invention is usually from 500 to 20,000, more preferably from 700 to 15,000 in terms of polystyrene converted by gel permeation chromatography. If the molecular weight is less than 500, the elongation at break of the cured product may be low, and if it exceeds 20,000, the viscosity may increase, which is not preferable.

  Urethane (meth) acrylate (A) can be used alone or in combination of two or more, and in particular, urethane (meth) acrylate produced from a polyol compound, a diisocyanate compound and a hydroxyl group-containing (meth) acrylate ( A1) and urethane (meth) acrylate (A2) produced from a diisocyanate compound and a hydroxyl group-containing (meth) acrylate are preferably used in combination.

  The urethane (meth) acrylate (A) may be blended in an amount of 30 to 90% by mass, more preferably 55 to 87% by mass, and particularly 65 to 85% by mass with respect to 100% by mass of the total amount of the liquid curable resin composition of the present invention. preferable. If it is less than 30% by mass, the temperature dependence of the elastic modulus is large, and if it is 90% by mass or more, the viscosity of the liquid curable resin composition may be high.

  Urethane (meth) acrylate (A1), (A2), (A3), and (A4) are each 20 to 60% by mass of component (A1) and 100% by mass of component (A2) with respect to 100% by mass of the total amount of component (A). ) Is 20 to 40% by mass, component (A3) is preferably 10 to 40% by mass, component (A4) is preferably 0 to 5% by mass, component (A1) is 30 to 50% by mass, and component (A2). Is more preferably 25 to 35% by mass, component (A3) is 20 to 30% by mass, and component (A4) is 0.1 to 3% by mass.

Component (B) used in the composition of the present invention is an alkyl (meth) acrylate represented by the following formula (5).
^{_{CH 2 = C (R 1)}} COO- (CH 2) n -CH (CH 3) 2 (5)
(R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 4 to 8)
Component (B) has a branched structure in which the hydrocarbon group bonded to the (meth) acryloyl group has a tendency to be less crystallized in the composition than a (meth) acrylate monomer that does not have a branched structure. For this reason, it has the effect of improving the storage stability of the composition, particularly the storage stability under low temperature conditions.

  Specific examples of the component (B) include isohexyl (meth) acrylate, isoheptyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) acrylate, and the like. Of these, isononyl (meth) acrylate is particularly preferable from the viewpoint of industrial applicability.

  The component (B) (meth) acrylate compound is preferably blended in an amount of 8 to 60% by mass, particularly 10 to 30% by mass, based on 100% by mass of the total amount of the liquid curable resin composition of the present invention. If the amount is less than 8% by mass, the viscosity increases, and the effect of improving the mechanical properties of the cured product is small. If the amount exceeds 60% by mass, the volatility increases, which is not preferable. Further, the component (B) is contained in an amount of 50% by mass or more with respect to 100% by mass of the total amount of the compound having one ethylenically unsaturated bond (excluding urethane (meth) acrylate) contained in the composition. It is preferable that 60 to 80% by mass is contained.

As the polymerization initiator of component (C) used in the present invention, a thermal polymerization initiator or a photopolymerization initiator can be used.
When the resin composition of the present invention is thermally cured, a thermal polymerization initiator such as a peroxide or an azo compound can usually be used. Specific examples include benzoyl peroxide, t-butyl-oxybenzoate, azobisisobutyronitrile, and the like.

  Moreover, when photocuring the resin composition of this invention, a photoinitiator can be used and a photosensitizer can be further added as needed. Here, as the photopolymerization initiator, for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2- Methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2 Chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) ) -2,4,4-trimethylpentylphosphine oxide; IRGACURE184, 369, 651, 500, 907, CGI1700, CGI1750, CGI1850, CG24-61, DAROCUR1116, 1173 (above, manufactured by Ciba Specialty Chemicals) ), LUCIRIN LR8728 (manufactured by BASF), Ubekrill P36 (manufactured by UCB) and the like. Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate. Isoamyl acid; commercially available products include Ubekryl P102, 103, 104, 105 (above, manufactured by UCB).

  The polymerization initiator (C) is preferably blended in an amount of 0.1 to 10% by mass, particularly 0.3 to 7% by mass with respect to 100% by mass of the total amount of the liquid curable resin composition of the present invention.

In the composition of the present invention, other than components (A) and (B), a compound having one ethylenically unsaturated group (component (D)) or a compound having two or more ethylenically unsaturated groups (component ( E)) can be blended.
Specific examples of such component (D) include, for example, vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam, isobornyl (meth) acrylate, bornyl (meth) acrylate, and tricyclodecanyl (meth) acrylate. , Alicyclic structure-containing (meth) acrylates such as dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, Examples include acryloyl morpholine, vinyl imidazole, and vinyl pyridine. Furthermore, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol mono (Meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, diacetone (meth) acrylamide, Isobutoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, t-octyl (meth) a Rilamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, N, N-diethyl (meth) acrylamide, N, N-dimethylaminopropyl ( Mention may be made of (meth) acrylamide, hydroxybutyl vinyl ether, lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether, vinyloxyethoxyethyl (meth) acrylate and vinyloxyethyl (meth) acrylate. Among these components (D), vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam are preferable from the viewpoint of improving the curing rate.

  Moreover, as a commercial item of the monofunctional compound of said polymerizable unsaturated monomer, Aronix M-111, M-113, M-114, M-117 (above, Toagosei Co., Ltd. make); KAYARAD, TC110S, R629, R644 (Nippon Kayaku Co., Ltd.); IBXA, Biscoat 3700 (Osaka Organic Chemical Co., Ltd.) and the like.

  Component (D) is preferably blended in an amount of 0.1 to 20% by mass, particularly 1 to 15% by mass, based on 100% by mass of the total amount of the liquid curable resin composition of the present invention.

  Examples of the component (E) include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di (meth). Acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tris (2- Hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol Di (meth) acrylate of diol of adduct of ethylene oxide or propylene oxide of A, di (meth) acrylate of diol of ethylene oxide or propylene oxide of hydrogenated bisphenol A, diglycidyl ether of bisphenol A (meta ) Epoxy (meth) acrylate added with acrylate, triethylene glycol divinyl ether, and the like. Commercially available products include, for example, Iupimer UV SA1002, SA2007 (manufactured by Mitsubishi Chemical Corporation); Biscoat 700 (manufactured by Osaka Organic Chemical Industry Co., Ltd.); KAYARAD R-604, DPCA-20, -30, -60, -120. , HX-620, D-310, D-330 (above, Nippon Kayaku Co., Ltd.); Aronix M-210, M-215, M-315, M-325 (above, Toagosei Co., Ltd.) .

  Since component (E) has the effect of increasing the crosslink density in the cured product, it is suitable for obtaining a Young's modulus suitable as a secondary material for forming a hard coating layer compared to the primary material. For this reason, it is preferable that the compounding quantity of a component (E) shall be 0.5-10 mass% with respect to 100 mass% of liquid curable resin composition whole quantity of this invention, especially 1-5 mass%.

  In addition to the above components, the liquid curable resin composition of the present invention includes various additives such as antioxidants, colorants, ultraviolet absorbers, light stabilizers, silane coupling agents, thermal polymerization inhibitors, and leveling agents. , Surfactants, storage stabilizers, plasticizers, lubricants, solvents, fillers, anti-aging agents, wettability improvers, coating surface improvers and the like can be blended as necessary.

  Here, examples of the antioxidant include IRGANOX 1010, 1035, 1076, 1222 (manufactured by Ciba Specialty Chemicals), ANTIGENE P, 3C, FR, GA-80 (manufactured by Sumitomo Chemical Co., Ltd.), and the like. Examples of the ultraviolet absorber include TINUVIN P, 234, 320, 326, 327, 328, 329, 213 (above, manufactured by Ciba Specialty Chemicals), Seesorb 102, 103, 501, 202, 712, 704 (above, Sipro Chemical Co., Ltd.). Manufactured) and the like. Examples of the light stabilizer include TINUVIN 292, 144, and 622LD (manufactured by Ciba Specialty Chemicals), Sanol LS770 (manufactured by Sankyo Company), TM-061 (manufactured by Sumitomo Chemical Co., Ltd.), and the like. Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and commercially available products such as SH6062, 6030 (above, manufactured by Toledo Corning Silicone Co., Ltd.). ), KBE903, 603, 403 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

Furthermore, other oligomers, polymers, other additives, and the like can be added to the composition of the present invention as long as they do not impair the properties of the composition of the present invention.
Examples of other oligomers and polymers include polyester (meth) acrylate, epoxy (meth) acrylate, polyamide (meth) acrylate, siloxane polymer having a (meth) acryloyloxy group, and glycidyl methacrylate.

  The viscosity of the liquid curable resin composition of the present invention is preferably 0.1 to 10 Pa · s, more preferably 1 to 8 Pa · s, and particularly preferably 2 to 6 Pa · s at 25 ° C. from the viewpoint of handling properties and applicability.

  The liquid curable resin composition of the present invention is cured by heat and / or radiation. Here, radiation refers to infrared rays, visible rays, ultraviolet rays, X rays, electron beams, α rays, β rays, γ. A line etc. are called and especially an ultraviolet-ray is preferable.

  The liquid curable resin composition of the present invention preferably has a Young's modulus at 25 ° C. of 100 to 2,500 MPa of a cured product obtained by curing.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Synthesis Example 1: Synthesis of urethane (meth) acrylate (A1)]
A reaction vessel equipped with a stirrer was charged with 10.68 g of 2,4-tolylene diisocyanate, 0.012 g of 2,6-di-t-butyl-p-cresol and 0.039 g of dibutyltin dilaurate, and these were stirred. However, the solution was cooled on ice until the liquid temperature became 10 ° C. or lower. 30.65 g of a ring-opened polymer of propylene oxide having a number average molecular weight of 1000 was added, and the mixture was reacted for 2 hours with stirring while controlling the liquid temperature to be 35 ° C. or lower. Next, 7.12 g of hydroxyethyl acrylate was added dropwise, and stirring was continued for 3 hours at a liquid temperature of 70 to 75 ° C., so that the residual isocyanate became 0.1% by mass (the amount based on the entire contents; the same applies hereinafter) or less. At the end of the reaction, urethane acrylate having a structure in which hydroxyethyl acrylate was bonded to both ends of propylene oxide via 2,4-tolylene diisocyanate was obtained. This urethane acrylate is referred to as urethane (meth) acrylate (UA-1).

[Synthesis Example 2: Synthesis of urethane (meth) acrylate (A2)]
A reaction vessel equipped with a stirrer was charged with 41.4 g of 2,4-tolylene diisocyanate, 0.02 g of 2,6-di-t-butyl-p-cresol, 0.08 g of dibutyltin dilaurate, and 0.008 g of phenothiazine. These were cooled until the liquid temperature reached 20 degrees with stirring. After 27.6 g of 2-hydroxyethyl acrylate was added dropwise while controlling the liquid temperature to be 25 ° C. or lower, the mixture was stirred and reacted at room temperature for 1 hour. Further, 30.9 g of 2-hydroxypropyl acrylate was added, and the mixture was stirred and reacted at a liquid temperature of about 60 degrees. When the residual isocyanate became 0.1% by mass or less, the reaction was terminated, and urethane acrylate which was an equimolar reaction product of 2,4-tolylene diisocyanate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate was obtained. This urethane acrylate is referred to as urethane (meth) acrylate (UA-2).

[Synthesis Example 3: Synthesis of urethane (meth) acrylate (A3)]
A reaction vessel equipped with a stirrer is charged with 42.9 g of 2,4-tolylene diisocyanate, 0.02 g of 2,6-di-t-butyl-p-cresol, 0.08 g of dibutyltin dilaurate, and 0.008 g of phenothiazine. These were cooled until the liquid temperature reached 20 degrees with stirring. After dropwise adding 57.1 g of 2-hydroxyethyl acrylate while controlling the liquid temperature to 25 ° C. or lower, the mixture was stirred and reacted at room temperature for 1 hour. Urethane acrylate having a structure in which 2-hydroxyethyl acrylate is bonded to both ends of 2,4-tolylene diisocyanate at the end of the reaction when the residual isocyanate is 0.1% by mass or less (amount based on the entire content; the same applies hereinafter). Got. This urethane acrylate is referred to as urethane (meth) acrylate (UA-3).

[Synthesis Example 4: Synthesis of urethane (meth) acrylate (A4)]
A reaction vessel equipped with a stirrer was charged with 1.59 g of 2,4-tolylene diisocyanate, 0.012 g of 2,6-di-t-butyl-p-cresol, and 0.039 g of dibutyltin dilaurate, and these were stirred. However, the solution was cooled on ice until the liquid temperature became 10 ° C. or lower. 1.06 g of hydroxyethyl acrylate was added dropwise while controlling the liquid temperature to be 20 ° C. or lower, and the mixture was further reacted by stirring for 1 hour. Next, 45.78 g of a ring-opening polymer of propylene oxide having a number average molecular weight of 10,000 is added, and stirring is continued for 3 hours at a liquid temperature of 70 to 75 ° C. At the end, urethane acrylate having a structure in which hydroxyethyl acrylate was bonded to both ends of propylene oxide via 2,4-tolylene diisocyanate was obtained. This urethane acrylate is referred to as urethane (meth) acrylate (UA-4).

Examples 1-3, Comparative Examples 1-2
Liquid curable resin compositions having the compositions shown in Table 1 were produced, and physical properties were evaluated according to the following methods. Table 1 shows the configurations (parts by mass) and evaluation results of the examples and comparative examples.

[Evaluation methods]
(1) Storage stability of resin solution:
The liquid curable resin composition was allowed to stand at −36 ° C. for 30 days and then visually observed to evaluate the storage stability. The case where it was transparent was designated as “◯”, and the case where white turbidity was observed was designated as “x”.

(2) Breaking strength and breaking elongation:
A liquid curable resin composition was applied on a glass plate using an applicator bar having a thickness of 200 μm, and was cured by irradiating with ultraviolet rays having an energy of 1 J / cm ² in the air to obtain a test film. Using a tensile tester (manufactured by Shimadzu Corporation, AGS-50G), the breaking strength and breaking elongation of the test piece were measured under the following measurement conditions.
Tensile speed: 50 mm / distance between marked lines (measurement distance): 25 mm
Measurement temperature: 23 ° C
Relative humidity: 50% RH

(3) Viscosity:
The viscosity at 25 ° C. of the compositions obtained in Examples and Comparative Examples was measured with a viscometer B8H-BII (manufactured by Tokimec).

(4) Young's modulus:
The Young's modulus after curing of the compositions obtained in Examples and Comparative Examples was measured. A liquid curable resin composition was applied onto a glass plate using an applicator bar having a thickness of 354 μm, and this was cured by irradiation with ultraviolet rays having an energy of 1 J / cm ^{2 in} the air to obtain a test film. A strip-shaped sample was prepared from the cured film so that the stretched portion had a width of 6 mm and a length of 25 mm. A tensile test was performed in accordance with JIS K7127 using a tensile tester AGS-1KND (manufactured by Shimadzu Corporation) under conditions of a temperature of 25 ° C. and a humidity of 50%. The Young's modulus was obtained from the tensile strength at a tensile rate of 1 mm / min and a strain of 2.5%.

(5) Curing speed:
The curing rate of the compositions obtained in the examples and comparative examples was measured. A liquid curable resin composition is applied on a glass plate using an applicator bar having a thickness of 200 μm, and this is cured by irradiating with ultraviolet rays having an energy of 20 mJ / cm ² and 1 J / cm ² in air. Got two kinds. From these two types of cured films, strip-shaped samples were prepared so that the stretched portions had a width of 6 mm and a length of 25 mm, respectively. A tensile test was performed in accordance with JIS K7127 using a tensile tester AGS-1KND (manufactured by Shimadzu Corporation) at a temperature of 23 ° C. and a humidity of 50%. The Young's modulus was obtained from the tensile strength at a tensile rate of 1 mm / min and a strain of 2.5%. The ratio of Young's modulus of the test film cured at 20 mJ / cm ² and Young's modulus of the test film cured at 500 mJ / cm ² was calculated from the formula (1), and the curing rate of the composition was evaluated.

(Equation 1)
Curing speed (%)
= [200 mJ / cm ² cured film Young's modulus] / [1 J / cm ² cured film Young's modulus] (1)

Isobornyl acrylate: IBXA (Osaka Organic Synthesis Co., Ltd.)
2-ethylhexyl acrylate: a compound represented by the following formula (BASF)
_{CH 2 = CHCOO-CH 2 CH} (CH 2 CH 3) - (CH 2) 3 -CH 3
Lauryl acrylate: a compound represented by the following formula (manufactured by Kyoeisha Chemical Co., Ltd.)
_{CH 2 = CHCOO- (CH 2)} 11 -CH 3
Trimethylolpropane triacrylate: TMP3A (manufactured by Osaka Organic Chemical Industry Co., Ltd.)
Lucillin: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF)
Irgacure 184; 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals)

Claims (5)

The following components (A1), (A2), (A3), (B) and (C):
(A1) Urethane (meth) acrylate having a structure represented by the following formula (1),
^{H-I-POL 1 -I-} H (1)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, and POL ¹ is an aliphatic polyether polyol having a number average molecular weight of 500 to 4,000. ]
(A2) urethane (meth) acrylate represented by the following formula (2),
HIH (2)
[In the above formula, two H are the same hydroxyl group-containing (meth) acrylate, and I is a polyisocyanate. ]
(A3) urethane (meth) acrylate represented by the following formula (3),
H ¹ -I-H ² (3)
[In the above formula, H ¹ and H ² are different hydroxyl group-containing (meth) acrylates, and I is a polyisocyanate. ]
(B) an alkyl (meth) acrylate represented by the following formula (5),
^{_{CH 2 = C (R 1)}} COO- (CH 2) n -CH (CH 3) 2 (5)
(R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 4 to 8)
(C) A liquid curable resin composition for a secondary material of an optical fiber containing a polymerization initiator. Furthermore, component (A4):
(A4) urethane (meth) acrylate having a structure represented by the following formula (4),
^{H-I-POL 2 -I-} H (4)
[In the above formula, each H is independently a hydroxyl group-containing (meth) acrylate, I is a polyisocyanate, POL ² is an aliphatic polyether polyol having a number average molecular weight exceeding 4,000 but not exceeding 12,000. is there. ]
The liquid curable resin composition for the secondary material of the optical fiber according to claim 1, comprising:   The said component (B) is contained 50 mass% or more with respect to 100 mass% of whole quantity of the compound (however, except urethane (meth) acrylate) which has one ethylenically unsaturated bond contained in a composition. Item 3. A liquid curable resin composition for a secondary material of an optical fiber according to Item 1 or 2.   The secondary coating layer of the optical fiber obtained by hardening | curing the liquid curable resin composition as described in any one of Claims 1-3.   An optical fiber having the secondary coating layer according to claim 4.