JP2015017210A - Curable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition containing urethane (meth) acrylate which is excellent in scratch resistance and flexibility due to scratch restoration and excellent in physical properties such as chemical resistance and low shrinkage. A curable resin composition containing urethane (meth) acrylate (X) obtained by reacting the following components (a) to (c). (A) polycaprolactone di or triol having 2 to 3 hydroxyl groups in one molecule and having a number average molecular weight per hydroxyl group in the range of 100 to 900 (b) allophanate modified di or triisocyanate ( c) Hydroxyl-containing (meth) acrylate [selection] None

Description

  The present invention relates to a curable resin composition containing urethane (meth) acrylate.

  Conventionally, curable resin compositions that are cured by active energy rays such as ultraviolet rays and electron beams and heat form cured products (coating and molded products) having scratch resistance, chemical resistance, etc. Widely used in applications such as coating agents, inks, adhesives and adhesives, and optical components. In recent years, these applications not only require scratch resistance and chemical resistance, but also various flexibility such as tensile elongation and flexibility, low shrinkage after curing and under high temperature and high humidity conditions, etc. Performance is required.

  As such a curable resin, urethane (meth) acrylate capable of forming a cured product having scratch resistance and flexibility is widely used. For example, polycaprolactone diol having a molecular weight of 800 to 8,000, isophorone diisocyanate. A urethane (meth) acrylate obtained by reacting a diisocyanate monomer such as 2-hydroxyethyl acrylate and the like with a hydroxyl group-containing (meth) acrylate has been reported (see Patent Document 1). However, since the urethane (meth) acrylate of Patent Document 1 has a large molecular weight of a soft segment composed of a polycaprolactone skeleton, a cured product obtained using this has excellent flexibility such as tensile elongation. However, the urethane bond concentration is low, and the toughness due to the cohesive force is lowered, resulting in a problem that the surface hardness is low and scratches are easily caused.

  Recently, there has been a demand for a method of forming a coating that can recover and remove minor scratches once attached, such as polycaprolactone polyol, organic isocyanates such as isophorone diisocyanate and lysine diisocyanate, and hydroxyl groups. A urethane (meth) acrylate obtained by reacting a contained (meth) acrylate has been reported (see Patent Document 2). However, although the resin composition of Patent Document 2 exhibits scratch resilience of scratches attached with nails, depending on the use, scratch resilience to a harder material such as a metal brush is required, and scratch resilience is required. There is a further demand for improvement. Further, since flexibility such as tensile elongation is not sufficient, there is a risk that cracks may occur due to deformation such as molding and the coating film may be peeled off from the substrate.

  Furthermore, as a curable resin composition containing urethane (meth) acrylate, urethane (meth) acrylate obtained by reacting polycarbonate diol, allophanate-modified diisocyanate, and hydroxyl group-containing (meth) acrylate has been reported (patent) Reference 3). However, although the resin composition of Patent Document 3 has been sufficiently studied for adhesion to a polycarbonate resin base material and coating properties, the polycarbonate diol skeleton has high crystallinity, so that the elastic recovery is low and the wound is restored. It has a problem that it is inferior in properties, and flexibility such as tensile elongation and bending resistance is not sufficient.

JP 2000-219821 A Japanese Patent Laid-Open No. 2004-35599 JP 2006-45361 A

  The problem to be solved by the present invention is a curable resin containing urethane (meth) acrylate, which has excellent scratch resistance and flexibility due to scratch recovery, and excellent physical properties such as chemical resistance and low shrinkage. It is to provide a composition.

As a result of intensive studies to solve the above problems, the present inventor has obtained urethane (meth) acrylate obtained by reacting specific polycaprolactone di or triol, allophanate-modified di or triisocyanate, and hydroxyl group-containing (meth) acrylate. As a result, the present inventors have found that a curable resin composition containing benzene is useful and completed the present invention.
That is, the present invention is as follows.
[1] A curable resin composition containing urethane (meth) acrylate (X) obtained by reacting the following components (a) to (c).
(A) polycaprolactone di or triol having 2 to 3 hydroxyl groups in one molecule and having a number average molecular weight per hydroxyl group in the range of 100 to 900 (b) allophanate modified di or triisocyanate ( c) Hydroxyl group-containing (meth) acrylate [2] A curable resin composition having a number average molecular weight per hydroxyl group of 150 to 500 in the polycaprolactone di or triol (a).
[3] The curable resin composition, wherein the allophanate-modified di- or triisocyanate (b) is an allophanate-modified product of an aliphatic and / or alicyclic diisocyanate and an aliphatic monoalcohol having 1 to 20 carbon atoms.

  The curable resin composition of the present invention is excellent in adhesion to the substrate, and the cured film has good scratch resistance such as restoration even if it is a scratch caused by a hard brush or the like. The cured film also has a sufficient tensile elongation and excellent flexibility, but has various physical properties such as low shrinkage and chemical resistance. Therefore, the curable resin composition of the present invention can be applied to a wide range of uses such as paints / coating agents, optical parts, inks, and adhesives / adhesives. In particular, it can be suitably used for film for insert molding such as an electronic device casing and membrane switch, a flexible display, a coating agent for an optical disc; and an optical sheet such as a light guide sheet, a prism sheet, and a lens sheet.

Details of the present invention will be described below.
The curable resin composition of the present invention is obtained by reacting (a) polycaprolactone di or triol, (b) allophanate-modified di or triisocyanate, and (c) hydroxyl group-containing (meth) acrylate. Contains acrylate (X).

<Polycaprolactone di or triol (a)>
The polycaprolactone di or triol (a) used in the present invention has a polycaprolactone structure and 2 to 3 hydroxyl groups in one molecule, and the number average molecular weight per hydroxyl group is in the range of 100 to 900. It is. The polycaprolactone di or triol is not particularly limited as long as it is in the above range, but is generally a compound obtained by ring-opening addition polymerization of caprolactone using a divalent or trivalent polyhydric alcohol as an initiator. The average added mole number of caprolactones relative to the polyhydric alcohol is set so that the number average molecular weight per hydroxyl group is in the range of 100 to 900.

  Examples of dihydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, 1,4-butanediol, 1,3-pentanediol, and 1,6-hexanediol. And cyclohexanedimethanol. Examples of the trihydric alcohol include glycerin, trimethylolpropane, triethylolpropane, 1,2,4-butanetriol and the like. Moreover, as caprolactone, (epsilon) -caprolactone, (delta) -caprolactone, (gamma) -caprolactone, etc. are mentioned.

  The polycaprolactone diol is, for example, a compound obtained by ring-opening addition polymerization of ε-caprolactone to the above dihydric alcohol, and ethylene glycol, diethylene glycol, neopentyl glycol, or 1,4-butanediol, ε- A compound obtained by ring-opening addition polymerization of caprolactone is preferred. The polycaprolactone triol is, for example, a compound obtained by ring-opening addition polymerization of ε-caprolactone to the above-mentioned trihydric alcohol, and ring-opening addition polymerization of ε-caprolactone to glycerin, trimethylolpropane, or triethylolpropane. The compound obtained is preferred.

  If one molecule has one hydroxyl group, the cured film formed by curing urethane (meth) acrylate has insufficient crosslink density, resulting in a decrease in elasticity and insufficient damage recovery. There is a risk that the wound will remain. On the other hand, when the number of hydroxyl groups in one molecule exceeds 3, it is not preferable because the crosslinking density of urethane (meth) acrylate becomes too high during production and gelation may occur.

  Moreover, when the number average molecular weight per hydroxyl group is less than 100, the crosslink density of the cured film becomes too high, and there is a possibility that the flaw restoration property is lowered. On the other hand, if the number average molecular weight per hydroxyl group exceeds 900, the crosslink density becomes too low and the flaw resilience deteriorates, which is not preferable. The number average molecular weight per hydroxyl group of polycaprolactone di or triol is preferably in the range of 150 to 500. In addition, the number average molecular weight and weight average molecular weight in this invention represent the molecular weight of standard polyethyleneglycol conversion measured by gel permeation chromatography (GPC), and the number average molecular weight per hydroxyl group is from following formula (1). Represents a calculated value.

  The polycaprolactone di or triol (a) used in the present invention may be a combination of two or more, in which case it is preferable to combine the polycaprolactone diol (a1) and the polycaprolactone triol (a2), and to the component (a2) It is preferable to combine the molar ratio [(a1) / (a2)] of the component (a1) in the range of 99/1 to 20/80.

  Examples of commercially available products include “Placcel 205”, “Plaxel 205H”, “Plaxel 205U”, “Plaxel L205AL”, “Plaxel 208”, “Plaxel 210”, “Plaxel 210N” manufactured by Daicel Corporation. , “Placcel 210CP”, “Placcel 212”, “Placcel 303”, “Placcel 305”, “Placcel 308”, “Placcel 309”, “Placcel 312”, “CAPA2047A”, “CAPA2054”, “CAPA2100” manufactured by Perstorp ”,“ CAPA2121 ”,“ CAPA3031 ”,“ CAPA3041 ”,“ CAPA3050 ”,“ CAPA3201 ”,“ Polylite OD-X-2155 ”,“ Polylite OD-X-2585 ”manufactured by DIC Corporation, and the like. It is.

<Allophanate-modified di- or triisocyanate (b)>
The allophanate-modified di- or triisocyanate (b) used in the present invention is a compound having at least one allophanate bond and 2 to 3 isocyanate groups in one molecule. The allophanate-modified di- or triisocyanate used in the present invention is not particularly limited as long as it is in the above range, but generally, according to a known method, the monoalcohol having 1 to 20 carbon atoms and the hydroxyl equivalent in the monoalcohol It is a compound obtained by modifying an allophanate in the presence of an allophanatization catalyst with an aliphatic, cycloaliphatic or aromatic diisocyanate monomer in an amount in which the isocyanate equivalent is excessive.

  Examples of the diisocyanate monomer include aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate; alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate and norbornane diisocyanate; 2,4- or 2,6-tolylene diisocyanate, m -Or p-phenylene diisocyanate, 1,3-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate and other aromatic diisocyanates. Examples of the monoalcohol having 1 to 20 carbon atoms include aliphatic monoalcohols such as methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, lauryl alcohol and stearyl alcohol; alicyclics such as cyclopentanol and cyclohexanol. Monoalcohol; phenols such as benzyl alcohol, phenol, phenylphenol, or aromatic monoalcohols.

  Among them, a compound obtained by allophanate-modifying an aliphatic or alicyclic diisocyanate monomer and an aliphatic monoalcohol having 1 to 20 carbon atoms from the viewpoint of wound resilience, tensile elongation, weather resistance and yellowing resistance. A compound obtained by modifying allophanate with hexamethylene diisocyanate or isophorone diisocyanate and an aliphatic monoalcohol having 1 to 9 carbon atoms is more preferable. These allophanate-modified di- or triisocyanates may be used alone or in combination of two or more.

  When one isocyanate group is contained in one molecule, the cured film formed by curing urethane (meth) acrylate has insufficient crosslinking density, so that the elasticity is lowered, and the wound resilience is sufficiently obtained. There is a risk that scratches will remain. On the other hand, when the number of isocyanate groups exceeds 3, it is not preferable because the crosslinking density of urethane (meth) acrylate becomes too high during production and may cause gelation. The present invention has a function of dramatically improving the flaw resilience and tensile elongation by using di- or triisocyanate having an allophanate bond in one molecule.

  Commercially available products include, for example, “Desmodur XP2580”, “Desmodur XP2565”, “Desmodur XP2803” manufactured by Sumika Bayer Urethane Co., Ltd., “Duranate A201H” manufactured by Asahi Kasei Chemicals Corporation, Japan “LVA-209”, “LVA-210”, “LVA-211” and the like manufactured by Polyurethane Co., Ltd. can be mentioned.

<Hydroxyl group-containing (meth) acrylate (c)>
The hydroxyl group-containing (meth) acrylate (c) used in the present invention is a hydroxyl group-containing (meth) acrylate having at least one hydroxyl group and one or more (meth) acryloyl groups in one molecule. The hydroxyl group-containing (meth) acrylate is not particularly limited as long as it is in the above range. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- Hydroxy-3-phenoxypropyl (meth) acrylate, ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate (average added mole number 1 to 10), polyethylene glycol (average added mole number 1 to 30) mono (meth) Examples include acrylate, polypropylene glycol (average added mole number 1-30) mono (meth) acrylate, pentaerythritol triacrylate, and the like. Among them, from the viewpoint of reactivity and versatility, ε- of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate Caprolactone adducts (average number of added moles of 1 to 10) are preferable, and 2-hydroxyethyl (meth) acrylate and ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate (average number of added moles of 1 to 3) are more preferable. . These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more.

<Urethane (meth) acrylate (X)>
The urethane (meth) acrylate (X) contained in the curable resin composition of the present invention is a compound obtained by reacting the components (a) to (c). A cured film formed by curing urethane (meth) acrylate by combining specific polycaprolactone di or triol (a) and allophanate-modified di or triisocyanate has a highly elastic three-dimensional crosslinked structure. Excellent wound resilience and tensile elongation.

(A) the mixing ratio of the time of the reaction ~ (c) component, (a) and (c) hydroxyl equivalent each present in component OH _a and _OH c, NCO isocyanate group equivalent contained in component (b) _In the case of _b , the ratio [NCO _b / (OH _a + OH _c )] of the isocyanate group equivalent of the component (b) to the total hydroxyl equivalent of the components (a) and (c) is usually in the range of 0.1-10. Yes, a range of 0.5 to 2 is preferable, and a range of 0.9 to 1.2 is more preferable. When the equivalent ratio [NCO _b / (OH _a + OH _c )] is less than 0.1, some of the components (a) and (c) remain as they are without being incorporated into the urethane (meth) acrylate skeleton, and have a scratch recovery property. It is not preferable because it may decrease. On the other hand, when the equivalent ratio [NCO _b / (OH _a + OH _c )] exceeds 10, the component (b) and the urethane prepolymer of the component (a) and the component (b) remain, so It is not preferable because the elongation and storage stability are lowered. However, this is not the case when the components (a) to (c) to be used are intentionally left in the composition.

Moreover, the ratio (OH _a / OH _c ) of the hydroxyl equivalent of the component (a) to the hydroxyl equivalent of the component ( _c ) is usually in the range of 0.1 to 15 and in the range of 0.4 to 8. Preferably, it is in the range of 0.9-3. When the equivalent ratio (OH _a / OH _c ) is less than 0.1, the elasticity of the cured film is low, and there is a possibility that the flaw resilience and the tensile elongation are lowered. On the other hand, when the equivalent ratio (OH _a / OH _c ) exceeds 15, the curability may be low, and the surface may be tacked.

  The production method of urethane (meth) acrylate (X) is not particularly limited, and a known method can be used, for example, polycaprolactone di or triol (a) and allophanate-modified di or triisocyanate (b). Can be obtained by reacting a hydroxyl group-containing (meth) acrylate (c). As another method, after reacting the component (b) and the component (c) first, the method of reacting the component (a), the method of reacting all the raw materials of the components (a) to (c) at once. Etc.

  When the urethane (meth) acrylate (X) is produced, a urethane-forming catalyst such as dibutyltin dilaurate or triethylamine is used for the purpose of accelerating the reaction rate, hydroquinone monomethyl ether (hereinafter referred to as “MEHQ”) or 2 for preventing polymerization. , 6-di-tert-butyl-4-methylphenol (hereinafter referred to as “BHT”) or a polymerization inhibitor may be blended. The blending amount of the urethanization catalyst and the polymerization inhibitor is usually in the range of 1 to 2,000 ppm, preferably in the range of 10 to 1,000 ppm, with respect to the total mass of the components (a) to (c). In addition, reaction temperature is the range of 10-100 degreeC normally, and it is preferable that it is the range of 40-80 degreeC.

  The weight average molecular weight of the urethane (meth) acrylate (X) of the present invention is in the range of 2,000 to 100,000, preferably in the range of 3,000 to 80,000, and in the range of 4,000 to 50,000. Is more preferable. When the weight average molecular weight is less than 2,000, the cured film formed by curing urethane (meth) acrylate has insufficient crosslink density, so that the elasticity is reduced, and scratch recovery is not sufficiently obtained. May remain. On the other hand, when the weight average molecular weight exceeds 100,000, the viscosity is remarkably increased, and thus workability such as handling and coating properties is deteriorated, which is not preferable.

  The curable resin composition of the present invention includes a photopolymerization initiator, an ethylenically unsaturated monomer other than the component (X), and a (meth) acrylic polymer as long as the effects of the present invention are not inhibited as optional components. , Epoxy (meth) acrylate, polyester (meth) acrylate, surface conditioner, leveling agent, filler, pigment, thixotropic agent, silane coupling agent, antistatic agent, antifoaming agent, antifouling agent, antioxidant UV absorbers, light stabilizers and the like can be blended.

<Photopolymerization initiator>
Examples of the photopolymerization initiator include benzoin and benzoin alkyl ethers such as benzoin and benzoin methyl ether; aromatic ketones such as benzophenone and benzoylbenzoic acid; benzyl ketals such as benzyldimethyl ketal and benzyldiethyl ketal; 1-hydroxycyclohexylphenyl Acetophenone such as ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl An acyl phosphine oxide such as phosphine oxide can be used. Among these, acetophenone such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2 Acylphosphine oxide such as 1,4,6-trimethylbenzoyl) phenylphosphine oxide is preferred, and acetophenone such as 1-hydroxycyclohexyl phenyl ketone is more preferred.

  The blending amount of the photopolymerization initiator is preferably in the range of 0.1 to 20% by mass, and in the range of 0.5 to 5% by mass with respect to the total mass of the resin solids containing urethane (meth) acrylate (X). Is more preferable. If it is less than 0.1% by mass, curing does not proceed sufficiently, and if it exceeds 20% by mass, the mass of the resin solids is relatively reduced, and the target physical properties of the cured product may be reduced.

The curable resin composition of the present invention can be obtained by blending urethane (meth) acrylate (X) and the above-mentioned additives as necessary and uniformly mixing them by a conventional method. The method of using the curable resin composition is not particularly limited, and a known method can be used. For example, a method of forming a film by coating on the surface of a base material or a mold is injected. And a method for producing a molded product.
The base material to apply | coat is not specifically limited, The base material of various materials, such as a plastics, a metal, wood, paper, glass, can be used. Examples of the plastic substrate include polyethylene resin, polypropylene resin, polybutadiene resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polymethyl methacrylate resin, polycarbonate resin, triacetyl cellulose (TAC) resin, Examples thereof include plastic films or molded articles such as polystyrene resin, polyvinyl chloride resin, ABS resin, and AS resin. Among these, PET resin is preferable from the viewpoint of transparency and toughness. As the coating method, it is possible to apply a coating method such as a gravure coating method, a roll coating method, a flow coating method or a bar coating method, or a printing method such as gravure printing or screen printing. The thickness of the coating film is usually from 1 to 200 μm, preferably from 3 to 100 μm, more preferably from 5 to 50 μm, from the viewpoint of scratch resilience. When the thickness exceeds 100 μm, the curability of the cured product is lowered, and there is a concern that the flaw restoration property and tensile elongation may be lowered. When the film thickness is less than 1 μm, the performance such as flaw restoration property may not be sufficiently obtained.

The curable resin composition of the present invention can be cured by irradiation with an active energy ray selected from the group consisting of infrared rays, visible rays, ultraviolet rays, X-rays, γ rays and electron beams. As a method of irradiating active energy rays, a normal curing method of a curable resin composition can be used. When ultraviolet rays are used as the active energy ray irradiation device, electrodeless lamps such as H bulb and D bulb manufactured by Fusion UV Systems, Inc. having a spectral distribution in the wavelength range of 200 to 450 nm, low pressure mercury lamp, high pressure mercury lamp, ultra high pressure Examples include a mercury lamp, a xenon lamp, a gallium lamp, and a metal halide lamp. The dose of the active energy rays are usually 10~3000mJ / cm ² as the accumulated light quantity is preferably 50~2000mJ / cm ^2. The atmosphere at the time of irradiation may be air or may be cured in an inert gas such as nitrogen or argon.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited by a following example. Unless otherwise specified, “parts” means “parts by mass” and “%” means “mass%”.

<Production Example 1; Production of urethane (meth) acrylate (X-1)>
In a four-necked flask equipped with a stirrer, air or nitrogen introduction tube, and thermometer, polycaprolactone diol (hydroxyl value 374 mgKOH / g, number average molecular weight 150 per hydroxyl group, hereinafter referred to as “PCL203” as component (a) ) 300 g, allophanate modified form of hexamethylene diisocyanate (hereinafter referred to as “HDI”) as component (b) (Desmodur XP2580, manufactured by Sumika Bayer Urethane Co., Ltd., isocyanate group content = 20.0%, hereinafter “XP2580” 840 g, dibutyltin dilaurate (hereinafter referred to as “DBTDL”) 0.27 g, and methyl isobutyl ketone (hereinafter referred to as “MIBK”) 915 g were charged and reacted for 5 hours while maintaining the internal temperature at 60 ° C. while blowing nitrogen. Subsequently, as component (c), 232 g of 2-hydroxyethyl acrylate (hydroxyl value 483 mg KOH / g, hereinafter referred to as “HEA”) and 0.27 g of MEHQ were added, and the mixture was reacted at the same temperature for 3 hours while blowing air. It was confirmed that the isocyanate group content was 0.1% or less, and 2,282 g of urethane (meth) acrylate (X-1) having a resin solid content of 60% and a weight average molecular weight of 11,000 was obtained.

<Production Examples 2 to 7, Comparative Production Examples 1 to 3; Production of urethane (meth) acrylates (X-2) to (X-7), (X′-1) to (X′-3)>
The urethane (meth) acrylates (X-2) to (X-7), and (X′-1) to (X ′) are the same as in Production Example 1 except that the raw materials and the charging amounts shown in Table 1 are changed. -3) was obtained.

<Comparative Production Example 4; Production of urethane (meth) acrylate (X'-4)>
A four-necked flask equipped with a stirrer, air or nitrogen inlet tube, and thermometer is charged with 699 g of XP2565, 232 g of HEA, 0.19 g of MEHQ, 0.19 g of DBTDL, and 380 g of MIBK, and blown with air. However, after reacting for 5 hours while maintaining the internal temperature at 60 ° C., it was confirmed that the isocyanate group content was 0.1% or less, and urethane (meth) acrylate having a resin solid content of 60% and a weight average molecular weight of 900 1,311g of (X'-4) was obtained.

<Comparative Production Example 5; Production of urethane (meth) acrylate (X'-5)>
In a four-necked flask equipped with a stirrer, air or nitrogen inlet tube, and thermometer, isocyanurate modified form of HDI (Duranate TPA-100, manufactured by Asahi Kasei Chemicals Corporation) as component (b ′), isocyanate group content = 23.0%, hereinafter referred to as “TPA-100”), 510 g of HEA, 232 g of HEA, and 0.25 g of MEHQ were added, and the reaction was performed for 5 hours while maintaining the internal temperature at 60 ° C. while blowing air. Subsequently, 500 g of PCL210 was added, and after reacting at the same temperature for 3 hours while blowing air, it was confirmed that the isocyanate group content was 0.1% or less, and the weight average molecular weight was 60% resin solid content. 2,070 g of 2,200 urethane (meth) acrylates (X′-5) were obtained.

In addition, the symbol in Table 1 represents the following compounds.
PCL205: polycaprolactone diol, hydroxyl value 212 mgKOH / g, number average molecular weight 265 per hydroxyl group
PCL210: polycaprolactone diol, hydroxyl value 114 mgKOH / g, number average molecular weight 492 per hydroxyl group
PCL312: polycaprolactone triol, hydroxyl value 135 mgKOH / g, number average molecular weight 416 per hydroxyl group
PCL320: polycaprolactone triol, hydroxyl value 84 mgKOH / g, number average molecular weight 668 per hydroxyl group
1,4-BD: 1,4-butanediol, hydroxyl value 1,246 mgKOH / g, number average molecular weight 45 per hydroxyl group
PCL220: polycaprolactone diol, hydroxyl value 56 mgKOH / g, number average molecular weight per hydroxyl group 1,002
XP2565: IPDI allophanate modified, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Desmodur XP2565, isocyanate group content = 12.0%, resin solid content 80% (butyl acetate)
IPDI: isophorone diisocyanate FA2D: ε-caprolactone adduct of 2-hydroxyethyl acrylate, manufactured by Daicel Corporation, product name: Plaxel FA2D, average added mole number of ε-caprolactone 2

<Examples 1-8, Comparative Examples 1-5; Preparation of curable resin composition and production of cured film>
In the proportions shown in Table 2, the urethane (meth) acrylate obtained in the above production example, the photopolymerization initiator, the ethylenically unsaturated monomer other than the urethane (meth) acrylate (X) of the present invention, and the additive, respectively. A curable resin composition was obtained by blending. Subsequently, the obtained curable resin composition was applied on an easily-adhesive PET film (Cosmo Shine A4300, film thickness 100 μm, manufactured by Toyobo Co., Ltd.) so that the dry film thickness was 20 μm, and the temperature was 80 ° C. And dried for 5 minutes to evaporate the organic solvent. Furthermore, the film which has a cured film was obtained by irradiating the ultraviolet-ray of the integrated light quantity 500mJ / cm <2> using the ultraviolet irradiation device (Fusion UV Systems Japan Co., Ltd. product, light source: H bulb). The obtained film was evaluated for adhesion, scratch resilience, tensile elongation, chemical resistance, and low shrinkage by the following methods.

<Adhesion>
In accordance with JIS K 5600, a film having a cured film prepared was stored at 60 ° C. and 90 RH% for 1 hour, cooled to 25 ° C., and then 100 100 mm squares were prepared with a cutter knife. When the commercially available cellophane tape was brought into close contact with the surface and peeled off at once, the number of grids remaining without peeling was determined according to the following criteria.
A: The number of remaining grids is 100.
A: The number of remaining grids is 90 to 99.
Δ: The number of remaining grids is 60 to 89.
X: The number of remaining grids is 59 or less.

<Scratch resilience>
When the film having the cured film layer thus produced was rubbed 5 times with a brass brush under a condition of 25 ° C. and 60 RH% for 5 reciprocations, the surface state of the cured product was visually determined according to the following criteria.
A: The wound is restored within 3 minutes.
○: Scratches are observed after 3 minutes, but are restored after 10 minutes.
Δ: Some scars are observed after 1 hour.
X: Scratches are not restored at all even after 1 hour.

<Tensile elongation>
The film having the cured film layer thus prepared is cut to a size of 10 mm × 60 mm, and set so that the distance between chucks is 40 mm using an autograph, and then at a tensile speed of 50 mm / min under conditions of 25 ° C. and 60 RH%. A tensile test was performed to determine the elongation when cracks occurred in the cured film. The evaluation criteria for the tensile elongation are as follows.
A: Tensile elongation is 50% or more.
○: The tensile elongation is 30 to less than 50%.
Δ: Tensile elongation is less than 20-30%.
X: The tensile elongation is less than 20%.

<Chemical resistance>
0.5 mL of ethanol was dropped on the prepared film having a cured film layer and left for 30 minutes under conditions of 23 ° C. and 60 RH%. Then, ethanol was removed with gauze, and the surface condition of the cured product was visually checked as follows. Judged by.
A: No abnormalities such as whitening, swelling, and peeling were observed on the surface.
A: Almost no abnormality such as whitening, swelling, or peeling was observed on the surface.
X: Abnormalities such as whitening, swelling, and peeling were confirmed on the surface

<Low shrinkage>
When a film having a cured film cut to 10 cm × 10 cm is heated for 1 hour under the conditions of 80 ° C. and 60 RH%, after being cooled to 25 ° C. and placed on a horizontal table with the cured film surface facing upward, The average value of the height of each of the four sides that floated was measured, and dimensional stability was determined according to the following criteria.
A: The average height is less than 3 mm.
A: The average height is 3 mm to less than 5 mm.
(Triangle | delta): The average value of height is 5 mm-less than 9 mm.
X: The average value of height is 9 mm or more.

In addition, the symbol in Table 2 represents the following compounds.
V # 2100: 2-acryloyloxypropyl phthalate, product name: Biscote # 2100, manufactured by Osaka Organic Chemical Industry Co., Ltd. ACMO: acryloylmorpholine, product name: ACMO, manufactured by Kojin Co., Ltd., Irg184: 1-hydroxy Cyclohexyl phenyl ketone, product name: Irgacure 184, manufactured by BASF Japan Ltd., BYK-3570: polyester-modified polydimethylsiloxane having a (meth) acryloyl group, product name: BYK-3570, manufactured by BYK Japan Japan Ltd., NANOBYK -3650: Silica particle dispersion surface-treated with an organic compound, product name: NANOBYK-3650, average particle size 20 nm, manufactured by Big Chemie Japan Co., Ltd.

  From the evaluation results shown in Table 2 above, the curable resin compositions of Examples 1 to 8 according to the present invention show that the slight scratches once attached are restored and disappeared, the tensile elongation, the adhesion, and the chemical resistance. It was excellent in all properties and curl resistance. On the other hand, depending on the curable resin composition of Comparative Examples 1 and 2 using a urethane (meth) acrylate in which polycaprolactone di or triol is outside the scope of the present invention, scratch resilience, tensile elongation, adhesion, chemical resistance The cured film satisfying all the properties and curl resistance could not be obtained. The cured films formed by the curable resin compositions of Comparative Examples 3 and 5 using a diisocyanate monomer or isocyanurate modified product not containing an allophanate bond have low elasticity of the crosslinked structure, and the scratches remain without being restored. It was. In addition, the curable resin composition of Comparative Example 4 that did not use polycaprolactone di or triol has low elasticity of the crosslinked structure in the formed cured film, the scratches remain without being restored, and the tensile elongation Was not enough.

Claims (3)

Curable resin composition containing urethane (meth) acrylate (X) obtained by making the following (a)-(c) component react.
(A) polycaprolactone di or triol having 2 to 3 hydroxyl groups in one molecule and having a number average molecular weight per hydroxyl group in the range of 100 to 900 (b) allophanate modified di or triisocyanate ( c) Hydroxyl group-containing (meth) acrylate   The curable resin composition of Claim 1 whose number average molecular weights per hydroxyl group of the said polycaprolactone di or triol (a) are the range of 150-500. The curing according to claim 1 or 2, wherein the allophanate-modified di- or triisocyanate (b) is an allophanate-modified product of an aliphatic and / or alicyclic diisocyanate and an aliphatic monoalcohol having 1 to 20 carbon atoms. Resin composition.