JP2007178454A - Radiation-curable resin composition for optical member and optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-curable resin composition for an optical member having a moderate viscosity before curing and capable of forming a cured object, after curing, having a high refractive index, excellent in adhesion to various plastic substrates, having such a moderate hardness as to infrequently distort a surface relief structure such as a fresnel lens, and less liable to yellow. <P>SOLUTION: The composition comprises (A) 5-70 mass% of urethane (meth)acrylate which is a reaction product of (a) a hydroxyl group-containing (meth)acrylate, (b) a polyisocyanate having an aromatic ring structure, (c) a polyol and (d) a 1-4C alcohol having no polymerizable unsaturated group, wherein (meth)acryloyl groups are present at 40-85 mol% of molecular terminals as an average in the reaction product, (B) 1-30 mass% of a (meth)acrylate compound represented by the formula: CH<SB>2</SB>=C(R)COO-C<SB>n</SB>H<SB>2n+1</SB>(where R is H or methyl and n is an integer of 4-12), and (C) 10-80 mass% of an ethylenically unsaturated group-containing compound other than the components (A) and (B). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation curable resin composition, and more particularly, a prism lens sheet used for a backlight of a liquid crystal display device, a lens sheet such as a Fresnel lens sheet and a lenticular lens sheet used for a screen of a projection television. The present invention relates to a radiation curable resin composition useful for forming an optical member such as a backlight using such a lens portion or a backlight, and an optical member containing the cured product.

Conventionally, lenses such as Fresnel lenses and lenticular lenses have been manufactured by a method such as a press method or a cast method. However, both methods require a long time to manufacture the lens and have poor productivity.
In order to solve such problems, in recent years, studies have been made to manufacture lenses using ultraviolet curable resins. Specifically, an ultraviolet curable resin composition is poured between a lens-shaped mold and a transparent resin substrate, and ultraviolet rays are irradiated from the substrate side to cure the composition. Can be manufactured.
Furthermore, with the recent thinning and enlargement of projection televisions and video projectors, various proposals and examinations according to various lens characteristics such as higher refractive index and mechanical characteristics have been made for resins forming lenses. ing. For example, an ultraviolet curable resin composition including urethane (meth) acrylate, an ethylenically unsaturated group-containing monomer, and a photopolymerization initiator has been proposed (see Patent Documents 1 to 3).

JP-A-4-288314 JP-A-5-255464 Japanese Patent Laid-Open No. 2001-200022

However, in such conventional ultraviolet curable resin compositions, there are demands required for lenses such as refractive index, adhesion to various plastic substrates (particularly adhesion in wet heat environment), and releasability from a mold. A cured product having sufficient characteristics could not be obtained.
Moreover, in the conventional ultraviolet curable resin composition, the viscosity has various sizes, and a lens having good performance has not always been obtained.

In order to solve the problems in such a conventional resin composition, the present inventors have conducted extensive research. As a result, (A) urethane (meth) acrylate in which a part of the terminal is sealed with an alcohol such as methanol, (B) formula: CH ₂ = C (R) in _{COO-C n H 2n + 1} [ wherein, R represents a hydrogen atom or a methyl radical, n is 4 to 12 integer. And (C) a radiation curable resin composition each containing a predetermined amount of an ethylenically unsaturated group-containing compound other than the component (A) and the component (B). Therefore, an optical member having an appropriate viscosity before curing, a high refractive index after curing, and good wet heat adhesion between the cured product of the composition and various plastic substrates (for example, a Fresnel lens) The present inventors have found that a transmission screen such as a lenticular lens can be obtained, and have completed the present invention.

That is, the present invention provides the following [1] to [11].
[1] (A) (a) a hydroxyl group-containing (meth) acrylate, (b) a polyisocyanate having an aromatic ring structure, (c) a polyol, and (d) having 1 to 4 carbon atoms having no polymerizable unsaturated group It is a reaction product of alcohol, and, as an average value in the reaction product, urethane (meth) acrylate 5 to 70% by mass, in which 40 to 85 mol% of molecular terminals are (meth) acryloyl groups,
(B) 1 to 30% by mass of a (meth) acrylate compound represented by the following formula (1)
CH ₂ = C (R) COO-C _n H _{2n + 1} (1)
[In formula, R is a hydrogen atom or a methyl group, and n is an integer of 4-12. ]
as well as,
(C) 10-80 mass% of ethylenically unsaturated group containing compounds other than said (A) component and (B) component
Radiation curable resin composition for optical members containing
[2] The radiation curable resin composition for optical members according to [1], wherein the component (A) has a structure represented by the following formula (2).
R ¹ -O- [CONH-R ² -NHCO-OR ³ -O] _n -CONH-R ² -NHCO-OR ¹ (2)
[Wherein, R ¹ represents a monovalent organic group having a (meth) acryloyl group or an alkyl group having 1 to 4 carbon atoms. R ² is a divalent organic group having an aromatic ring, and R ³ is a divalent organic group having 2 to 60 carbon atoms. n is an integer of 2-6. R ¹ is, as an average, a 40 to 85 mole percent (meth) acryloyl groups, 15 to 60 mol% are alkyl groups having 1 to 4 carbon atoms. A plurality of R ¹ present in the molecule are independent of each other and may be the same or different. The same applies to R ² and R ³ present in a molecule. ]
[3] The radiation curable resin composition for an optical member according to [1] or [2], wherein R ^{3 in the} formula (2) has a bisphenol structure.
[4] R ^{3 in the} formula (2) is represented by the following formula (3)
-[CH ₂ -C (CH ₃ ) HO] _m -Ph-C (CH ₃ ) ₂ -Ph- [OC (CH ₃ ) H-CH ₂ ] _m- (3)
(In the formula, Ph represents a p-phenylene structure. M is an integer of 1 to 3.)
The radiation curable resin composition for optical members according to any one of the above [1] to [3], which is represented by:
[5] The radiation curable resin composition for an optical member according to any one of [1] to [4], wherein the component (B) is 2-ethylhexyl (meth) acrylate.
[6] The radiation curable resin composition for an optical member according to any one of [1] to [5], wherein the viscosity at 25 ° C. is 1,500 to 2,500 mPa · s.
[7] The radiation curable resin composition for an optical member according to any one of [1] to [6], wherein the optical member is an optical lens.
[8] An optical member comprising a cured product obtained by irradiating the radiation curable resin composition according to any one of [1] to [7] with radiation.
[9] The optical member according to [8], which is an optical lens.
[10] The optical member according to [9], which is a Fresnel lens of a micro display projection television.
[11] Any of [8] to [10] above, wherein a cured product of the radiation curable resin composition is formed in close contact with a transparent plastic substrate mainly composed of methyl methacrylate / styrene copolymer. An optical member according to claim 1.

According to the radiation curable resin composition for an optical member of the present invention, it has a high refractive index, excellent adhesion to various plastic substrates (particularly methyl methacrylate / styrene copolymer), and has an uneven surface structure such as a Fresnel lens. A cured product having an appropriate hardness (Young's modulus) that is not easily distorted and little yellowing can be formed.
According to the cured product comprising the radiation curable resin composition for optical members of the present invention, an optical member having a high refractive index (for example, a micro-display projection TV) having excellent adhesion between the cured product and various plastic substrates. Can be produced.
The radiation curable resin composition for an optical member of the present invention has an appropriate viscosity and can form a lens having good performance.

Urethane (meth) acrylate as component (A) used in the radiation curable resin composition for optical members of the present invention (hereinafter also referred to as composition of the present invention) is (a) hydroxyl group-containing (meth) acrylate, (B) a reaction product of a polyisocyanate having an aromatic ring structure, (c) a polyol, and (d) a C1-C4 alcohol having no polymerizable unsaturated group.
In the composition of the present invention, since the component (d) is contained in the raw material, not all of the molecular terminals of the component (A) are (meth) acryloyl groups.
As a mean value of the urethane (meth) acrylate of the component (A), the ratio of the (meth) acryloyl group in the group constituting the molecular end is 40 to 85 mol%. If the ratio is less than 40 mol%, the Young's modulus of the cured film may be reduced, and the concavo-convex structure on the surface of the Fresnel lens may be distorted. Decreases. Here, in the reaction product of the components (a), (b), (c) and (d), there may be a molecular species having both ends sealed with the component (d). The said average value is an average value which makes the whole reaction material of (a), (b), (c) and (d) component a parameter.
In the present specification, since the component (A) is partially sealed with alcohol (component (d)) and the remainder is a (meth) acryloyl group, Also referred to as “sealed urethane (meth) acrylate”. The molecular end sealed with alcohol is an alkyl group having 1 to 4 carbon atoms.

The component (A) more preferably has a structure represented by the following formula (2).
R ¹ -O- [CONH-R ² -NHCO-OR ³ -O] _n -CONH-R ² -NHCO-OR ¹ (2)
[Wherein, R ¹ represents a monovalent organic group having a (meth) acryloyl group or an alkyl group having 1 to 4 carbon atoms. R ² is a divalent organic group having an aromatic ring, and R ³ is a divalent organic group having 2 to 60 carbon atoms. n is an integer of 2-6. R ¹ is, as an average, a 40 to 85 mole percent (meth) acryloyl groups, 15 to 60 mol% are alkyl groups having 1 to 4 carbon atoms. A plurality of R ¹ present in the molecule are independent of each other and may be the same or different. The same applies to R ² and R ³ present in a molecule. ]

Components (a) to (d), which are raw materials for component (A), will be described in detail.
(A) Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenyloxypropyl. (Meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neo Pentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta ( Data) acrylate, the following formula (4)

(In the formula, R ⁴ represents a hydrogen atom or a methyl group, and v represents an integer of 1 to 15)
(Meth) acrylate represented by the following. Moreover, the compound obtained by addition reaction with glycidyl group containing compounds, such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate, and (meth) acrylic acid can also be used. These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more.

  Examples of (b) organic polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and 1,5-naphthalene diisocyanate. , 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 Etc. In particular, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate are preferably used.

  Furthermore, as (c) polyol, for example, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,3-butanediol, cyclohexanedimethylol, tri Cyclodecane dimethylol, 1,6-hexanediol, 2-butyl-2-ethyl-propanediol, bisphenol A polyethoxyglycol, bisphenol A polypropoxyglycol, bisphenol A polyethoxypropoxyglycol, bisphenol F polyethoxyglycol, bisphenol F Polypropoxy glycol, Bisphenol F polyethoxypropoxy glycol, Bisphenol S polyethoxy glycol, Bisphenol S polypropoxy glycol, Bi Phenol S polyethoxy propoxy glycol, polytetramethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene butylene glycol, polycaprolactone diol, polyester diol, and polycarbonate diol.

  In particular, in terms of refractive index, bisphenol A poly (preferably degree of polymerization: n = 2 to 40 as an average value) ethoxy glycol, bisphenol A poly (preferably degree of polymerization: n = 2 to 40 as an average value) propoxy glycol, bisphenol A poly (preferably degree of polymerization: n = 2 to 40 as an average value) ethoxypropoxy glycol, bisphenol F poly (preferably degree of polymerization: n = 2 to 40 as an average value) ethoxy glycol, bisphenol F poly (preferably degree of polymerization) : Average value n = 2 to 40) propoxy glycol, bisphenol F poly (preferably polymerization degree: n = 2 to 40 as average value) ethoxypropoxy glycol, bisphenol S poly (preferably polymerization degree: n = 2 as average value) -40) Ethoxy glycol, bisphenol S poly ( Preferably, the degree of polymerization: n = 2 to 40 as an average value, and propoxyglycol and bisphenol S poly (preferably the degree of polymerization: n = 2 to 40 as an average value) are used as one kind or two or more kinds selected from ethoxypropoxyglycol. It is preferable.

As a particularly preferred polyol, the following formula (5):
_{HO- [CH 2 -C (CH 3} ) HO] m -Ph-C (CH 3) 2 -Ph- [OC (CH 3) H-CH 2] m -OH (5)
(In the formula, Ph represents a p-phenylene structure. M is an integer of 1 to 3, preferably 1 or 2.)
The alkylene oxide addition diol of bisphenol A shown by these is mentioned.
As a commercial item of the alkylene oxide addition diol of bisphenol A, DB400 (made by NOF Corporation, m = 3) etc. are mentioned, for example.

(D) In order for C1-C4 alcohol to seal a part of terminal of the urethane (meth) acrylate obtained, and not to participate in the polymerization reaction for hardening the resin composition of this invention. Added. The component (d) is preferably a monohydric alcohol such as methanol or ethanol from the viewpoint of improving adhesion.
As the component (d), methanol is particularly preferable from the viewpoint of improving adhesion. By sealing the partial end of urethane (meth) acrylate with an alcohol having 1 to 4 carbon atoms, the mechanism is unknown, but the adhesion to various plastic substrates can be improved.

  Among the raw materials of partially terminal alcohol-sealed urethane (meth) acrylate, (a) a hydroxyl group-containing (meth) acrylate having a hydroxyl group capable of reacting with an isocyanate group, and (d) an alcohol having 1 to 4 carbon atoms is (a ) Hydroxyl group-containing (meth) acrylate: (d) the molar ratio of the alcohol having 1 to 4 carbon atoms is required to be reacted within the range of 85:15 to 40:60, and 85:15 to 70:30. The reaction is preferably performed within the range, and the reaction is particularly preferably performed at 76:24. Outside the above range, the adhesion to the substrate is reduced.

As a method for producing a partially terminal alcohol-capped urethane (meth) acrylate as component (A), (i) a polyol and an organic polyisocyanate are reacted, and then a hydroxyl group-containing (meth) acrylate and an alcohol having 1 to 4 carbon atoms. (Ii) a method of reacting an organic polyisocyanate, a hydroxyl group-containing (meth) acrylate and an alcohol having 1 to 4 carbon atoms, and then reacting a polyol, (iii) a polyol, an organic polyisocyanate, a hydroxyl group-containing (meta ) A method in which an acrylate and an alcohol having 1 to 4 carbon atoms are charged and reacted at once.
Among these, any method may be used to obtain a partially terminal alcohol-capped urethane (meth) acrylate used in the present invention. Preferably, the method (ii) (organic polyisocyanate, hydroxyl group) is used. A method of reacting the containing (meth) acrylate and the alcohol having 1 to 4 carbon atoms and then reacting the polyol is preferable.

When producing the partially terminal alcohol-capped urethane (meth) acrylate as component (A), (a) hydroxyl group-containing (meth) acrylate, (b) polyisocyanate having an aromatic ring structure, (c) polyol, and ( d) The proportion of each of the alcohols having 1 to 4 carbon atoms is such that (b) the isocyanate group contained in the polyisocyanate having an aromatic ring structure is 1.1 to 1 equivalent to 1 equivalent of the hydroxyl group contained in the polyol. It is preferable that the total of the hydroxyl groups of (a) the hydroxyl group-containing (meth) acrylate and (d) the alcohol having 1 to 4 carbon atoms is 0.1 to 1 equivalent.
Furthermore, with respect to 1 equivalent of the hydroxyl group contained in the polyol, the isocyanate group contained in (b) the organic polyisocyanate having an aromatic ring structure is 1.3 to 2 equivalents, and (a) the hydroxyl group-containing (meth) acrylate and (D) It is particularly preferable that the total number of hydroxyl groups of the alcohol having 1 to 4 carbon atoms is 0.3 to 1 equivalent.
When it deviates from this preferable range, it becomes difficult to handle the resin composition in a liquid state such as an increase in viscosity.

  When producing the component (A) partially terminal alcohol-capped urethane (meth) acrylate, usually copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin dilaurate, triethylamine, triethylenediamine- A urethanization catalyst such as 2-methyltriethyleneamine is used in an amount of 0.01 to 1% by mass based on the total amount of reaction raw materials. The reaction temperature is usually 10 to 90 ° C, particularly 30 to 80 ° C.

  The number average molecular weight of the partially terminal alcohol-capped urethane (meth) acrylate as the component (A) is preferably 500 to 20,000, more preferably 1,000 to 15,000. When the number average molecular weight is less than 500, the adhesiveness of the cured product obtained by curing the resin composition to the substrate decreases. Conversely, when the number average molecular weight exceeds 20,000, Viscosity is high and handling is easy.

  The partially terminal alcohol-capped urethane (meth) acrylate as the component (A) is preferably blended in the resin composition in an amount of 5 to 70% by mass, particularly preferably 10 to 60% by mass. If the blending amount is less than 5% by mass, it may be difficult to impart mechanical properties such as appropriate toughness to the cured product. When the blending amount exceeds 70% by mass, the viscosity of the resin composition increases, and workability and coatability may be deteriorated.

The component (B) used in the radiation curable resin composition of the present invention is a (meth) acrylate compound represented by the following formula (1).
CH ₂ = C (R) COO-C _n H _{2n + 1} (1)
[In formula, R is a hydrogen atom or a methyl group, and n is an integer of 4-12. ]

Specific examples of the component (B) include butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl ( (Meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl ( Examples include meth) acrylate and lauryl (meth) acrylate.
Among these, those in which n in formula (1) is 8 or 9 are preferably used from the viewpoint of workability. Further, 2-ethylhexyl (meth) acrylate in which n is 8 is particularly preferably used from the viewpoint that the viscosity is moderate and the stability of the liquid resin composition is good.

  (B) The compounding quantity of a component becomes like this. Preferably it is 1-30 mass% in the radiation-curable resin composition of this invention, More preferably, it is 5-20 mass%. If it is less than 1% by mass, the viscosity of the liquid composition becomes high, and it becomes difficult to obtain a lens having good performance. When it exceeds 30 mass%, a viscosity will become low and the effect of the improvement of the mechanical characteristics of hardened | cured material will become small.

(C) component used for the radiation-curable resin composition of this invention is an ethylenically unsaturated group containing compound other than (A) component and (B) component. Examples of the component (C) include a compound containing a (meth) acryloyl group or a vinyl group and does not correspond to the component (A) and the component (B) (hereinafter referred to as “unsaturated monomer”). Is mentioned.
As the unsaturated monomer, a monofunctional monomer and a polyfunctional monomer can be used.

  Examples of monofunctional monomers include vinyl monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, vinylimidazole, and vinylpyridine; phenoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meta ) Acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl) -2-hydroxypropyl ( (Meth) acrylate, (meth) acrylate of p-cumylphenol reacted with ethylene oxide, 2-bromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate , 2,4,6-tribromophenoxyethyl (meth) acrylate, phenoxy (meth) acrylate, isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodeca modified with plural moles of ethylene oxide and propylene oxide Nyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Propyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (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) acrylamide , Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, N, N-diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) ) Acrylamide, hydroxybutyl building ether, lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether and the following formulas (6) and (7):

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkylene group having 2 to 8 carbon atoms, and w represents an integer of 1 to 8).

(In the formula, R ⁷ and R ⁹ each independently represent a hydrogen atom or a methyl group, R ⁸ represents an alkylene group having 2 to ⁸ carbon atoms, and x represents an integer of 1 to 8)
The compound etc. which are represented by these are mentioned.
Of these, phenoxyethyl (meth) acrylate and the like are preferable.

Multifunctional monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol Propanetrioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloyloxy) isocyanurate, (Hydroxymethyl) tricyclodecane di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, di (meth) acrylate of diol which is an adduct of bisphenol A polyethylene oxide or propylene oxide, ethylene of hydrogenated bisphenol A Examples include di (meth) acrylate of diol, which is an adduct of oxide or propylene oxide, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, triethylene glycol divinyl ether, and the like.
Among these, dipentaerythritol hexa (meth) acrylate, tripropylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, di (meth) of diol which is an adduct of polyethylene oxide or propylene oxide of bisphenol A Acrylate and the like are preferable.

Examples of commercially available monofunctional monomers include Aronix M101, M102, M110, M111, M113, M117, M5700, TO-1317, M120, M150, M156 (above, manufactured by Toagosei Co., Ltd.), LA, IBXA, and 2-MTA. HPA, Viscoat # 150, # 155, # 158, # 190, # 192, # 193, # 220, # 2000, # 2100, # 2150 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate BO-A, EC-A, DMP-A, THF-A, HOP-A, HOA-MPE, HOA-MPL, PO-A, P-200A, NP-4EA, NP-8EA, epoxy ester M-600A
(Made by Kyoeisha Chemical Co., Ltd.), KAYARAD TC110S, R-564, R-128H (Made by Nippon Kayaku Co., Ltd.), NK Ester AMP-10G, AMP-20G (Made by Shin-Nakamura Chemical Co., Ltd.), FA -511A, 512A, 513A (manufactured by Hitachi Chemical Co., Ltd.), PHE, CEA, PHE-2, PHE-4, BR-31, BR-31M, BR-32 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), VP (Manufactured by BASF), ACMO, DMAA, DMAPAA (above, manufactured by Kojin Co., Ltd.) and the like.

  Moreover, as a commercial item of a polyfunctional monomer, for example, Iupimer UV SA1002, SA2007 (above, manufactured by Mitsubishi Chemical Corporation), Biscoat # 195, # 230, # 215, # 260, # 335HP, # 295, # 300, # 360 , # 700, GPT, 3PA (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate 4EG-A, 9EG-A, NP-A, DCP-A, BP-4EA, BP-4PA, TMP-A, PE- 3A, PE-4A, DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD PET-30, TMPTA, R-604, DPHA, DPCA-20, -30, -60, -120, HX-620, D- 310, D-330 (above, Nippon Kayaku Co., Ltd.), Aronix M208, M210, M215, M220, M240, M305, M 309, M310, M315, M325, M400 (above, manufactured by Toagosei Co., Ltd.), Lipoxy VR-77, VR-60, VR-90 (above, Showa Polymer Co., Ltd.) and the like.

  The component (C) is preferably blended in the radiation curable resin composition of the present invention in an amount of 10 to 80% by mass, particularly preferably 20 to 80% by mass. When the blending amount is less than 10% by mass, the viscosity of the liquid resin composition and the refractive index of the cured product may be inferior. When the blending amount exceeds 80% by mass, it may be inferior in terms of maintaining sufficient mechanical properties and coating properties.

The radiation curable resin composition of the present invention is cured by radiation. Here, the radiation means ionizing radiation such as infrared rays, visible rays, ultraviolet rays and X-rays, electron beams, α rays, β rays, and γ rays, and light such as ultraviolet rays is usually used conveniently. In the photocuring reaction, if necessary, a photopolymerization initiator as component (D) is added, and if necessary, a photosensitizer is added.
Any photopolymerization initiator may be used as long as it can be decomposed by light irradiation to generate radicals to initiate polymerization. For example, acetophenone, acetophenone benzyl ketal, 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, benzyl dimethyl 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-propane- Examples thereof include 1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, and the like.

  (D) Examples of commercially available photopolymerization initiators include Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI-1700, -1750, -1850, CG24-61, Darocur l116, 1173 (and above). Ciba Specialty Chemicals), Lucirin TPO, LR8883, LR8970 (above, 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 etc. are mentioned, As a commercial item, Ubekrill P102, 103, 104, 105 (above, UCB company make) etc. are mentioned, for example.

  The optimum blending amount of the photopolymerization initiator (D) for curing the resin composition of the present invention is preferably 0.01 to 10% by mass, particularly preferably 0.5 to 7% by mass in the resin composition. When the blending amount is less than 0.01% by mass, the curing rate may decrease and the reaction efficiency may be lowered. When the blending amount exceeds 10% by mass, the curing characteristics and handling properties of the liquid resin composition, The mechanical properties and optical properties of the cured product may be inferior.

  When hardening the resin composition of this invention, a thermal-polymerization initiator can also be used together as needed. Preferred examples of the thermal polymerization initiator include peroxides and azo compounds. Specific examples include benzoyl peroxide, t-butyl-peroxybenzoate, azobisisobutyronitrile, and the like.

In addition to the components described above, other curable oligomers or polymers can be blended with the resin composition of the present invention as needed, as long as the characteristics of the resin composition of the present invention are not impaired.
Examples of other curable oligomers or polymers include polyurethane (meth) acrylates other than component (A), polyester (meth) acrylates, epoxy (meth) acrylates, polyamide (meth) acrylates, and (meth) acryloyloxy groups. Examples thereof include a siloxane polymer, a reactive polymer obtained by reacting a copolymer of glycidyl (meth) acrylate and other polymerizable monomer and (meth) acrylic acid.

Furthermore, in addition to the above components, various additives as necessary include, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization inhibitors, leveling agents, surfactants. , Coloring agents, storage stabilizers, plasticizers, lubricants, mold release agents, solvents, fillers, anti-aging agents, wettability improvers and the like can be blended as necessary.
Here, examples of the antioxidant include Irganox 1010, 1035, 1076, 1222 (above, manufactured by Ciba Specialty Chemicals), Antigen 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 (and above, manufactured by Ciba Specialty Chemicals), Seesorb 102, 103, 110, 501, 202, 712, and 704 (and above). , Manufactured by Sipro Kasei Co., Ltd.).
Examples of the light stabilizer include Tinuvin 292, 144, 622LD (manufactured by Ciba Specialty Chemicals), Sanol LS770 (manufactured by Sankyo Co., Ltd.), Sumisorb 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, Toray Dow Corning Silicone). Co., Ltd.), KBE903, 603, 403 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.
Examples of the coating surface improving agent include silicone additives such as dimethylsiloxane polyether, and commercially available products include DC-57, DC-190 (above, manufactured by Dow Corning), SH-28PA, SH-29PA, SH. -30 PA, SH-190 (above, manufactured by Toray Dow Corning Silicone), KF351, KF352, KF353, KF354 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), L-700, L-7002, L-7500, FK- 024-90 (manufactured by Nihon Unicar).

  The resin composition of the present invention can be produced by mixing the above components by a conventional method. The viscosity of the resin composition of the present invention thus prepared is usually 1,500 to 2,500 mPa · s / 25 ° C., preferably 1,700 to 2,300 mPa · s / 25 ° C., particularly preferably 1. 800-2,100 mPa · s / 25 ° C. If the viscosity is too high, unevenness of application or waviness (warping after curing reaction) occurs during the production of the lens, or it becomes difficult to obtain the target lens thickness, and the performance as a lens cannot be exhibited sufficiently. On the other hand, if it is too low, it is difficult to control the lens thickness, and a uniform lens with a constant thickness may not be formed.

  Further, the refractive index at 25 ° C. of the cured product of the resin composition of the present invention is preferably 1.53 or more, more preferably 1.54 or more. When the refractive index is less than 1.53, when a transmissive screen is formed using a resin composition, sufficient front luminance may not be ensured.

  Moreover, the Young's modulus (40 degreeC) of the hardened | cured material of the resin composition of this invention becomes like this. Preferably it is 300-800 MPa, More preferably, it is 400-600 MPa. When the Young's modulus is within the above preferable range, the cured product has an appropriate hardness, so that the surface uneven structure such as a Fresnel lens is hardly distorted.

The cured product obtained by irradiating the resin composition of the present invention with radiation is useful as a lens part such as a prism lens sheet, a Fresnel lens sheet, a lenticular lens sheet, or an optical member such as a backlight using such a sheet. It is particularly useful as an optical lens.
Among such optical lenses, in particular, an ultraviolet curable resin composition is poured between a lens-shaped mold and a transparent plastic base material, and ultraviolet rays are irradiated from the base material side to thereby apply the composition. An optical lens produced by curing is preferred.
Therefore, a preferable optical lens obtained by the present invention is a lens obtained by bringing a cured product (lens body) made of the resin composition of the present invention into close contact with a transparent plastic substrate.
Examples of the transparent plastic substrate include a substrate mainly composed of polymethyl methacrylate (PMMA) and a substrate mainly composed of methyl methacrylate / styrene copolymer (MS). Among these, a substrate mainly composed of methyl methacrylate / styrene copolymer (MS) is particularly preferable.

  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]
In a reaction vessel equipped with a stirrer, 2,4-tolylene diisocyanate 32.94% by mass (representing the ratio of the total amount of materials used; the same applies hereinafter), dilauric acid di-n-butyltin 0.08% by mass, 2,6-Di-t-butyl-p-cresol 0.02 mass% was charged. While stirring, 12.59 mass% of 2-hydroxyethyl acrylate was added dropwise so that the temperature was maintained at 30 ° C or lower. After completion of the dropwise addition, the mixture was reacted at 30 ° C. for 1 hour. Next, 54.37 mass% of bisphenol A polypropoxy glycol (DB400 manufactured by NOF Corporation) was added, and the reaction was continued at 50 to 70 ° C. for 2 hours. The reaction was terminated when the residual isocyanate was 0.1% by mass or less.
The urethane acrylate obtained by this method was designated “Oligomer A-1.”
"Oligomer A-1" does not correspond to the component (A) of the present invention because the proportion of acryloyl group in the group at the molecular end is 100 mol%.

[Synthesis Example 2: Synthesis of 24% terminal methanol-capped urethane (meth) acrylate]
Charge 0.85% by mass of methanol together with 2,4-tolylene diisocyanate, 33.73% by mass of 2,4-tolylene diisocyanate, 9.77% by mass of 2-hydroxyethyl acrylate, bisphenol A polypropoxy glycol 24% terminal methanol-capped urethane (meth) acrylate was synthesized in the same manner as in Synthesis Example 1 except that the amount was 55.66% by mass.
The obtained partially terminal methanol-capped urethane acrylate was referred to as “Oligomer A-2”.
The number of moles of methanol is 24% of the total number of moles of 2-hydroxyethyl acrylate and methanol.
“Oligomer A-2” corresponds to the component (A) of the present invention, in which the ratio of acryloyl groups in the molecular end groups is 76 mol% as an average value in the total amount of oligomers.

[Synthesis Example 3: Synthesis of 12% terminally methanol-capped urethane (meth) acrylate]
Charge 0.42% by mass of methanol together with 2,4-tolylene diisocyanate and the like, 33.36% by mass of 2,4-tolylene diisocyanate, 11.18% by mass of 2-hydroxyethyl acrylate, bisphenol A poly ( Degree of polymerization: m = 3 as an average value) A 12% terminal methanol-capped urethane (meth) acrylate was synthesized in the same manner as in Synthesis Example 1 except that propoxyglycol was changed to 55.04% by mass.
The obtained partially terminal methanol-capped urethane acrylate was referred to as “Oligomer A-3”.
The number of moles of methanol is 12% of the total number of moles of 2-hydroxyethyl acrylate and methanol.
“Oligomer A-3” has a ratio of acryloyl group in the group at the molecular end of 88 mol% as an average value in the total amount of the oligomer, and does not correspond to the component (A) of the present invention.

Example 1
In a reaction vessel equipped with a stirrer, 27 mass% of (A-2) as component (A), 9 mass% of 2-ethylhexyl acrylate as component (B), and 21 mass of dipentaerythritol hexaacrylate as component (C) %, Bisphenol A ethylene oxide-added acrylate 13% by mass, phenoxyethyl acrylate 28% by mass, (D) component 1-hydroxycyclohexyl phenyl ketone was added in a proportion of 2% by mass, Were added, and the mixture was stirred for 1 hour while controlling the liquid temperature at 50 to 60 ° C. to obtain a uniform liquid curable resin composition.

  In addition, also about Example 2 and Comparative Examples 1-4, each component of the composition shown in Table 1 was prepared to reaction container, and each liquid curable resin composition was obtained. The unit of each component amount in Table 1 is parts by mass. (E) component in Table 1 shows additives other than (A)-(D) component.

<Evaluation method>
Using the liquid curable resin compositions obtained in Examples 1 and 2 and Comparative Examples 1 to 4, a test piece was created by the following method, and viscosity, substrate adhesion, Young's modulus, And ΔYI (change in yellow index over time) were measured.

[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 Co., Ltd.).

[Base material adhesion]
After applying a liquid curable resin composition to a mold having a Fresnel lens shape (hereinafter abbreviated as a lens mold), a 1.8 mm-thick methyl methacrylate / styrene copolymer (MS) substrate (10 cm × 10 cm) was used to cover the mold from the side of the resin composition so that bubbles would not enter, and then the MS substrate was pressurized so that the resin composition layer had a constant thickness (100 μm).
Then, after irradiating 1.0 J / cm ² of ultraviolet rays from the substrate side to cure the resin composition layer, a lens made of a cured product (lens) of the liquid curable resin composition and an MS substrate from the mold. The substrate was peeled off by hand. The method of peeling the lens substrate peeled from the mold from the interface between the lens and the MS substrate using a cutter knife, and the adhesion with the MS substrate from the peeling surface side in accordance with JIS K5400 It was evaluated in a test.
At this time, the case where no peeling was made by the method of peeling with a cutter knife, and in the cross-cut peel test, no cross-cut was peeled off from the MS substrate, and it was completely adhered, In the peeling method, partly peels off, but in the cross-cut peel test, if the cross-cut is not peeled off from the MS substrate and is completely bonded, “○”, and in the cross-cut peel test, The case where the eyes were peeled off from the MS substrate was “Δ”, and the case where all the grids were peeled off from the MS substrate in the cross-cut peel test was indicated as “X”.

[Young's modulus]
The Young's modulus of the cured product of the liquid curable resin composition was measured as follows.
First, after applying a liquid curable resin composition on a glass plate using an applicator bar having a thickness of 381 μm, the composition layer is irradiated with ultraviolet rays having an energy of 1 J / cm ^{2 in} the air to be cured. A film was obtained. 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 on the strip-shaped sample according to JIS K7127 using a tensile tester at a temperature of 40 ° C. and a humidity of 50%. The tensile rate was 1 mm / min, and the Young's modulus (MPa) was determined from the tensile strength at 2.5% strain.

[ΔYI]
ΔYI (change in yellow index indicating the degree of yellowing over time) of the cured product of the liquid curable resin composition was measured as follows.
First, a liquid curable resin composition was applied on a slide glass using an applicator having a thickness of 253 μm, and then the composition layer was irradiated with ultraviolet rays of 1.0 J / cm ² using a metal halide lamp, A cured film having a thickness of about 130 μm was obtained.
The cured film on the slide glass was placed in an environment at a temperature of 100 ° C. for 7 days.
The hue change was evaluated by YI (yellow index) using a color difference meter (SZ-Σ80 spectral color difference meter manufactured by Nippon Denshoku Industries Co., Ltd.). The difference between the YI value after standing for 7 days and the YI value immediately after production of the cured film was taken as the ΔYI value. The smaller the ΔYI value, the smaller the degree of increase in yellowing over time and the smaller the change in hue over time.

Each component in Table 1 is as follows.
[B-1]
2-ethylhexyl acrylate (manufactured by Nippon Shokubai Co., Ltd .; trade name: 2-AEH)
[B-2]
Lauryl acrylate (manufactured by Kyoeisha Chemical; trade name: Light Acrylate LA)
[C-1]
Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd .; trade name: KAYARAD DPHA)
[C-2]
Ethylene oxide-added acrylate of bisphenol A (Osaka Organic Chemical Co., Ltd .; trade name: Biscoat # 700)
[C-3]
Phenoxyethyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd .; trade name: New Frontier PHE)
[D-1]
Irgacure 184
(Ciba Specialty Chemicals; 1-hydroxycyclohexyl-phenyl-ketone; radical photopolymerization initiator)
[E-1]
Irganox 1035
(Ciba Specialty Chemicals, Inc .; 2,2′-thiodiethyl-bis- (3,5-di-t-butyl-4-hydroxyphenyl) propionate)
[E-2]
Tinuvin 292
(Ciba Specialty Chemicals; 1-methyl-8- (1,2,2,6,6-pentamethyl-4-piperidinyl) -sebacate)
[E-3]
DC-190
(Toray Dow Silicon Co., Ltd .; dimethylpolysiloxane polyoxyalkylene copolymer)
[E-4]
DC-57
(Toray Dow Silicon Co., Ltd .; dimethylpolysiloxane polyoxyalkylene copolymer)
[E-5]
ADDID700
(Degussa; silicone blend)

From the results of Table 1, the cured products of the radiation curable resin compositions of Examples 1 and 2 using the component (A) and the component (B) defined in the present invention are viscosity, substrate adhesion, Young's modulus, And ΔYI value (small change in hue over time). On the other hand, in Comparative Examples 1 to 4 in which the component (A) and the component (B) defined in the present invention are not used together, it can be seen that the substrate adhesion, the ΔYI value, and the like are inferior.

Claims (11)

(A) Reaction of (a) hydroxyl group-containing (meth) acrylate, (b) polyisocyanate having an aromatic ring structure, (c) polyol, and (d) a C1-C4 alcohol having no polymerizable unsaturated group 5 to 70% by mass of urethane (meth) acrylate, in which 40 to 85 mol% of the molecular terminals are (meth) acryloyl groups as an average value in the reaction product,
(B) 1 to 30% by mass of a (meth) acrylate compound represented by the following formula (1),
CH ₂ = C (R) COO-C _n H _{2n + 1} (1)
[In formula, R is a hydrogen atom or a methyl group, and n is an integer of 4-12. ]
as well as,
(C) 10-80 mass% of ethylenically unsaturated group containing compounds other than said (A) component and (B) component
Radiation curable resin composition for optical members containing The radiation curable resin composition for optical members according to claim 1, wherein the component (A) has a structure represented by the following formula (2).
R ¹ -O- [CONH-R ² -NHCO-OR ³ -O] _n -CONH-R ² -NHCO-OR ¹ (2)
[Wherein, R ¹ represents a monovalent organic group having a (meth) acryloyl group or an alkyl group having 1 to 4 carbon atoms. R ² is a divalent organic group having an aromatic ring, and R ³ is a divalent organic group having 2 to 60 carbon atoms. n is an integer of 2-6. R ¹ is, as an average, a 40 to 85 mole percent (meth) acryloyl groups, 15 to 60 mol% are alkyl groups having 1 to 4 carbon atoms. A plurality of R ¹ present in the molecule are independent of each other and may be the same or different. The same applies to R ² and R ³ present in a molecule. ] The radiation curable resin composition for an optical member according to claim 1, wherein R ^{3 in the} formula (2) has a bisphenol structure. R ^{3 in the} formula (2) is the following formula (3)
-[CH ₂ -C (CH ₃ ) HO] _m -Ph-C (CH ₃ ) ₂ -Ph- [OC (CH ₃ ) H-CH ₂ ] _m- (3)
(In the formula, Ph represents a p-phenylene structure. M is an integer of 1 to 3.)
The radiation curable resin composition for optical members of any one of Claims 1-3 shown by these.   The said (B) component is 2-ethylhexyl (meth) acrylate, The radiation curable resin composition for optical members of any one of Claims 1-4.   The radiation curable resin composition for an optical member according to any one of claims 1 to 5, wherein the viscosity at 25 ° C is 1,500 to 2,500 mPa · s.   The said optical member is an optical lens, The radiation curable resin composition for optical members of any one of Claims 1-6.   The optical member containing the hardened | cured material obtained by irradiating a radiation-curable resin composition of any one of Claims 1-7 with a radiation.   The optical member according to claim 8, wherein the optical member is an optical lens.   The optical member according to claim 9, which is a Fresnel lens of a micro-display projection television. The cured product of the radiation curable resin composition is formed in close contact with a transparent plastic substrate mainly composed of methyl methacrylate / styrene copolymer. Optical member.