JPH11223703A - Optical member with low double refraction, its forming resin composition and production of optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical member which is lightweight and has low double refraction, excellent transparency, heat resistance, mechanical strength, especially shock resistance, and low water absorptivity by polymerizing and hardening a resin compsn. comprising a specified (meth)acrylate compd., a specified mercapto compd. and a specified (meth)acrylate compd. SOLUTION: A resin compsn. containing a component (A), component (B) and component (C) is molded and hardened by photopolymn. The component (A) consists of an alicyclic hydrocarbon bis(meth)acrylate expressed by formula I and is included by 32 to 94.9 pts.wt. The component (B) consists of one kind of mercapto compd. selected from formula II or the like and is included by 0.1 to 8 pts.wt. The component (C) consists of a bisphenol-A bisacrylate expressed by formula III and is included by 5 to 60 pts.wt. In formula I, R<1> , R<2> are each independently hydrogen or CH3 , (p) is an integer of 1 or 2, (q) is 0 or 1. In formula II, R<3> is -CH2 or the like, R<4> is an alkylether residue or the like and (a) is an integer of 2 to 6. In formula III, R<6> to R<11> are each independently hydrogen or the like, (r) and (s) are each an integer of 0 to 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member, and more particularly to a high impact resistant low birefringent optical member suitable for a liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display panel using a glass plate as a substrate has been demanded because such a panel is limited in terms of reduction in glass density and improvement in mechanical strength. It is difficult to cope with light weight and thinness. Further, problems have been pointed out from the viewpoints of moldability and workability regarding the improvement of productivity, and attention has been paid to panels using plastic as a substrate. However, such a plastic substrate has the following problems. Lack of transparency and optical isotropy suitable for liquid crystal display. Poor heat resistance.

In particular, with respect to optical isotropy, the current state is that the birefringence Δn · d of a glass plate is 1 nm or less, while that of a plastic plate exceeds 10 nm. This problem of birefringence is difficult to resolve by a molding method in which some stretching operation or material flow operation is performed on the resin, and when a relatively thick substrate (for example, 0.4 mm or more) is used, Molding is difficult by extrusion of thermoplastic resin or belt molding. On the other hand, when a thermosetting resin is used, there is a production problem that a molding time is several hours.

As a means for solving this problem, there are two or more radically reactive unsaturated bonds in the molecule ((meth))
A method for obtaining a low-birefringence optical member by polymerizing and curing a resin composition comprising an acrylate compound and a mercapto compound having two or more thiol groups in a molecule with an active energy ray in the presence of a photo-radical polymerization initiator is proposed. (Japanese Patent Application No. 8-90928). This system has superior impact resistance as compared with a glass substrate, and is preferably used as a substrate of a liquid crystal display panel. there were. In particular, cracking and chipping due to insufficient mechanical strength of the substrate in the demolding step after the molding of a large area sheet of A3 size or more was a major factor in lowering the yield.

[0005]

According to the present invention, a low-birefringence optical member having low weight, low birefringence, excellent transparency, heat resistance, excellent mechanical strength, especially impact resistance, and low water absorption, particularly a liquid crystal panel. An object of the present invention is to provide a suitable low birefringence optical member, a method for producing the same, and a resin composition for molding the same.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that an alicyclic hydrocarbon skeleton having two or more radically reactive unsaturated bonds in the molecule. A resin composition of a (meth) acrylate compound, a mercapto compound having two or more thiol groups in a molecule, and a (meth) acrylate compound having a bisphenol (A) skeleton is polymerized and cured by an active energy ray. The inventors have found that an impact-resistant low birefringent optical member can be obtained, and have reached the present invention. That is, the present invention provides a low birefringence optical member obtained by molding a resin composition containing the following component A, component B, and component C, followed by photopolymerization and curing. Component (A): 32 to 94.9 parts by weight of an alicyclic hydrocarbon skeleton bis (meth) acrylate represented by the following general formula [I].

[0007]

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[R ¹ and R ² may be the same or different and each is hydrogen or CH ₃ , p is an integer of 1 or 2,
q is 0 or 1] Component (B): 0.1 to 8 parts by weight of at least one mercapto compound selected from the following formulas [II], [III] and [IV].

[0009]

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[R ³ is —CH ₂ — or —CH ₂ CH ₂ —
Wherein R ⁴ is a C _2-15 hydrocarbon residue or an alkyl ether residue, and a is an integer of 2 to 6]

[0011]

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[X is HS- (CH _2- ) _b (CO)-
(OCH ₂ CH ₂ ) _d- (CH ₂ ) _c- (b, d is 1 to
An integer of 8 and c is 0 to 2)]

[0013]

Embedded image

[R ⁵ is a hydrocarbon group which may contain oxygen,
e is an integer of 2 or more] Component (C): 5 to 60 parts by weight of a bisphenol A skeleton bis (meth) acrylate represented by the following general formula [V].

Embedded image [R ^{6 to} R ⁹ may be the same or different, each may be hydrogen or CH ₃ or a halogen atom, R ¹⁰ and R ¹¹ may be the same or different, and each of hydrogen or CH ₃ , r and s is 0 to An integer of 7 and may be the same or different.] A resin composition for a low birefringence optical member comprising the above components A, B, and C. A method for producing a low birefringence optical member, comprising: molding a resin composition containing the above components A, B, and C, and irradiating the resin composition with an active energy ray to perform photopolymerization and curing. is there.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a specific alicyclic hydrocarbon skeleton bis (meth) acrylate monomer, a specific mercapto compound and a specific bis (meth) acrylate monomer having a bisphenol A skeleton. The present invention relates to a polymerizable resin composition to be formed, a low birefringent optical member obtained by molding and photopolymerizing and curing the same, and a method for producing the same. Here, “comprising” means that a small amount of auxiliary components may be contained as long as the gist of the present invention is not impaired.

That is, other monomers copolymerizable with the component specified in the present invention, specifically, for example,
Up to about 30 parts by weight per 100 parts by weight of the ingredients
It means that they may be used together. In addition, each component may be used in combination between and / or within the components. In addition, "(meth) acryl" and "(meth) acrylate" are generic terms for acryl or methacryl and acrylate or methacrylate. <Component (A): bis (meth) acrylate> Component (A)
Is an alicyclic hydrocarbon skeleton bis (meth) acrylate represented by the formula [I].

[0017]

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The symbols in the formula have the following meanings. R ¹ and R ² : a hydrogen atom or a methyl group. R ¹ , R ²
May be the same or different. p: an integer of 1 or 2. q: 0 or 1.

Specific examples of the alicyclic hydrocarbon skeleton bis (meth) acrylate compound represented by the formula [I] include bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = diacrylate Bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate,
Bis (oxymethyl) tricyclo [2.2.1.
0 ^{2, 6]} decane = acrylate methacrylate and mixtures thereof, bis (oxymethyl) pentacyclo [6.
5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane diacrylate, bis (oxymethyl) pentacyclo [6.
5.1.1 ^3,6 . 0 ^{2, 7,} 0 ^9,13] pentadecane = dimethacrylate, bis (oxymethyl) pentacyclo [6.5.1.1 ^{3, 6.} [0 ^{2,7,0 9,13} ] pentadecane acrylate methacrylate and mixtures thereof. Two or more of these tricyclodecane compounds and pentacyclodecane compounds may be used in the group and / or between the groups. These compounds can be synthesized, for example, by the method described in JP-A-62-225508.

<Component (B): Mercapto Compound> Component (B) is at least one selected from mercapto compounds having two or more thiol groups in the molecule represented by formulas [II], [III] and [IV]. One type of mercapto compound.

[0021]

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The symbols in the formula have the following meanings. R ³ : a methylene group or an ethylene group. R ⁴ : a hydrocarbon residue having 2 to 15 carbon atoms which may contain ether oxygen and thioether sulfur. Preferably 2 to 2 carbon atoms
6 hydrocarbon residues. a: an integer of 2 to 6. X: HS- (CH _2- ) _b (CO)-(OCH ₂ C
_{H 2) d - (CH 2} ) c - (b, d is an integer of 1 to 8, c is 0~2)] R ^5: a hydrocarbon group which may contain oxygen. e: an integer of 2 or more.

The mercapto compound represented by the formula [II] is
Divalent to hexavalent thioglycolate or thiopropylate. Specific examples of the compound of the formula [II] include, for example, pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), trimethylolpropane tris (β-thiopropionate), trimethylolpropane Tris (thioglycolate), diethylene glycol bis (β-thiopropionate), diethylene glycol bis (thioglycolate), triethylene glycol bis (β-thiopropionate), triethylene glycol (thioglycolate), dipenta Erythritol hexakis (β-thiopropionate) and dipentaerythritol hexakis (thioglycolate).

The compound of the formula [III] is an isocyanurate containing an ω-SH group. Specific examples of the compound of the formula [III] include, for example, tris [2- (β-thiopropionyloxy) ethyl] isocyanurate, tris (2-thioglyconyloxyethyl) isocyanurate, tris [2- (β- Thioglyconyloxyethoxy) ethyl]
Isocyanurate, tris (2-thioglyconyloxyethoxyethyl) isosifnurate, tris [3- (β
-Thiopropionyloxy) propyl] isocyanurate, tris (3-thioglyconyloxypropyl) isocyanurate and the like.

The compound represented by the formula [IV] is an SH group-containing hydrocarbon. Specific examples of the compound of the formula [IV] include, for example, benzenedimercaptan, xylylenedimercaptan, 4,4'-dimercaptodiphenylsulfide, polypropylene glycol diglycidyl ether S
Hydride, bisphenol A diglycidyl ether SH hydride and the like.

The alicyclic hydrocarbon skeleton bis (meth) acrylate of the component (A) can be polymerized by itself, but the cured resin obtained has large birefringence and mechanical strength such as impact resistance. There is a disadvantage that is inferior. By blending the mercapto compound of the component (B) represented by the general formulas [II] to [IV], the thiol group in the mercapto compound acts as a chain transfer agent, and the polymerization hardens smoothly and uniformly. In addition, the birefringence of the cured resin can be greatly reduced. Further, it can enter the three-dimensional network structure formed by the alicyclic hydrocarbon skeleton bis (meth) acrylate compound of the above [I], and can impart appropriate toughness. In the present invention, the above-mentioned problem of birefringence is first solved without greatly impairing the heat resistance of the obtained cured product, because it has two or more thiol groups in the molecule, that is, uses a polyfunctional mercapto compound. can do.

The composition ratio of the mercapto compound in the present invention is from 0.1 to 8 parts by weight, preferably from 1 to 8 parts by weight, based on 100 parts by weight of all the monomer components. If the proportion of the mercapto compound is too small, the effect of improving the birefringence of the cured resin will not be obtained, and if it is too large, the heat resistance of the cured resin will be low. <Component (C): bisphenol A skeleton bis (meth) acrylate> The component (C) is a bisphenol A skeleton bis (meth) acrylate represented by the formula [V].

[0028]

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The symbols in the formula have the following meanings. R ^{6 to} R ⁹ : a hydrogen atom, a methyl group, or a halogen atom.
R ^{6 to} R ⁹ may be the same or different. R ¹⁰ to R ^11: a hydrogen atom or a methyl group. They may be the same or different. r and s: integers from 0 to 7. r and s may be the same or different.

Specific examples of bisphenol A skeleton bis (meth) acrylate compounds represented by the formula [V] include bisphenol A diacrylate, bisphenol A dimethacrylate, bisphenol A acrylate methacrylate and mixtures thereof, and bisphenol A bis [(oxyethyl ) Ether] = diacrylate, bisphenol A bis [(oxyethyl) ether] = dimethacrylate, bisphenol A bis [(oxyethyl) ether] = acrylate methacrylate and mixtures thereof, tetrabromobisphenol A bis [(oxyethyl) ether] = di Acrylate, tetrabromobisphenol A bis [(oxyethyl) ether]
= Dimethacrylate, tetrabromobisphenol A bis [(oxyethyl) ether] = acrylate methacrylate and mixtures thereof, bisphenol A bis [(dioxyethyl) ether] = diacrylate, bisphenol A bis [(dioxyethyl) ether] =
Dimethacrylate, bisphenol A bis [(dioxyethyl) ether] = acrylate methacrylate and mixtures thereof, bisphenol A bis [(polyoxyethyl) ether] = diacrylate, bisphenol A bis [(polyoxyethyl) ether] = dimethacrylate, Bisphenol A bis [(polyoxyethyl)
Ether] = acrylate methacrylate and mixtures thereof.

The present invention is characterized in that a bisphenol A skeleton bis (meth) acrylate of the component (C) is blended. By blending the bisphenol (bis) (meth) acrylate of the component (C), a moderately tough structure of bisphenol A becomes a three-dimensional network formed by the alicyclic hydrocarbon skeleton bis (meth) acrylate and a mercapto compound. When incorporated, the mechanical strength such as the impact resistance of the cured product can be dramatically improved.

In the present invention, the composition ratio of the bis (meth) acrylate bisphenol A skeleton is based on the total amount of the monomer components 1
5 to 60 parts by weight, preferably 8 to 50 parts by weight to 00 parts by weight
Parts by weight, more preferably 8 to 40 parts by weight. If the proportion of bis (meth) acrylate in the bisphenol A skeleton is too small, the effect of improving the mechanical strength such as the impact resistance of the cured resin cannot be obtained. The characteristics are impaired, which is not preferable.

<Auxiliary component> The low birefringence member of the present invention is obtained by polymerizing and curing a resin composition containing components (A), (B) and (C). As described above, the auxiliary component may be contained. Therefore, the resin composition for a low birefringence optical member of the present invention,
It is also possible to produce the composition by mixing and copolymerizing other radically polymerizable monomers in an amount of up to about 30 parts by weight with respect to 100 parts by weight of the composition before curing. Other monomers used at this time include, for example, methyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, methacryloyloxymethyltetracyclodecane, methacryloyloxymethyltetracyclododecene, ethylene Glycol di (meta)
Acrylate, diethylene glycol di (meth) acrylate, 1,6-hexenediol di (meth) acrylate, 2,2-bis [4- (β-methacryloyloxyethoxy) phenyl] propane, 2,2′-bis [4-
(Β-methacryloyloxyethoxy) cyclohexyl] propane, (meth) acrylate compounds such as 1,4-bis (methacryloyloxymethyl) cyclohexane, trimethylolpropane tri (meth) acrylate, styrene, chlorostyrene, divinylbenzene, α
Core and / or side chain substituted and unsubstituted styrenes such as -methylstyrene. Among these other monomers, methacryloyloxymethylcyclododecane,
2,2-bis [4- (β-methacryloyloxyethoxy) phenyl] propane, 2,2-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane, 1,4-bis (methacryloyloxymethyl) cyclohexane, And mixtures thereof are particularly preferred. Other auxiliary components include antioxidants, ultraviolet absorbers, dyes and pigments, and fillers.

<Polymerization Curing> The resin composition comprising the components A, B and C in the present invention is molded and cured. The curing is performed by a known radical polymerization in which a photopolymerization initiator that generates a radical by an active energy ray such as ultraviolet light is added. As the photopolymerization initiator used at that time, for example, benzophenone, benzoin methyl ether, benzoin isopropyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone,
Examples thereof include 2,6-dimethylbenzoyldiphenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Preferred photopolymerization initiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide M and benzophenone.

Two or more photopolymerization initiators may be used in combination. The addition amount of these photopolymerization initiators is 100
0.01 to 1 part by weight, preferably 0.02 part by weight based on part by weight
０．３0.3 parts by weight. If the amount of the photopolymerization initiator is too large, the polymerization proceeds rapidly, causing not only an increase in birefringence but also a deterioration in hue. If the amount is too small, the composition cannot be cured sufficiently. The amount of the active energy ray to be irradiated is arbitrary as long as the photopolymerization initiator generates radicals.However, when the amount is extremely small, the heat resistance and mechanical properties of the cured product are sufficiently exhibited due to incomplete polymerization. On the contrary, if the amount is extremely excessive, deterioration of the cured product due to light such as yellowing occurs. Therefore, ultraviolet rays having a wavelength of 200 to 400 nm are preferably adjusted to 0 to 400 depending on the composition of the monomer and the type and amount of the photopolymerization initiator. Irradiate in the range of .1 to 200j. Specific examples of lamps used include metal halide lamps,
High-pressure mercury lamps and the like can be mentioned.

For the purpose of promptly completing the curing, thermal polymerization may be used in combination. That is, the composition and the entire mold are heated in the range of 30 to 300 ° C. simultaneously with the light irradiation. In this case, a radical polymerization initiator may be added in order to complete the polymerization better, but excessive use causes an increase in birefringence and a deterioration in hue. Specific examples of the thermal polymerization initiator include benzoyl peroxide, diisopropyl peroxy carbonate, t-butyl peroxy (2-ethylhexanoate), and the amount used is 1 part by weight or less based on 100 parts by weight of the monomer. Is preferred.

Further, in the present invention, the completion of the polymerization reaction and the internal strain generated during the polymerization can be reduced by heating the cured product after performing the radical polymerization by light irradiation. The heating temperature is appropriately selected according to the composition of the cured product and the glass transition temperature. However, since excessive heating results in deterioration of the hue of the cured product, a temperature around the glass transition temperature or lower is preferable.

A gas barrier film can be formed on the surface of the cured product obtained by the present invention by various methods, and can be used as an optical member with a gas barrier. Known gas barrier films can be used.
For example, a single layer or a stack of silicon oxide such as SiOx, PVA, an acrylic resin, or the like can be used.

Various transparent conductive films can be preferably formed on the surface of the cured product obtained by the present invention by various methods, and can be used as an optical member with a transparent electrode. There is no particular limitation on the transparent conductive film that can be formed on the surface of the cured product. For example, Au, Ag, Cu, Pd, Al, C
r, Rh or other metal conductive film, In ₂ O ₃ , SnO ₂ , Cd
An oxide semiconductive film of ₂ SnO ₄ , CdO or the like may be used. Of these, In ₂ O ₃ , SnO ₂ and Cd ₂ Sn
O ₄ is preferable in terms of conductivity, transparency, film strength, and the like. Further, so-called ITO in which In ₂ O ₃ is doped with Sn is most preferable. The method for forming the transparent conductive film is not particularly limited. For example, a spray method, a gas phase reaction method (CVD)
Method), a chemical film forming method such as a coating method, and a physical film forming method such as a vacuum evaporation method and a sputtering method.

The optical member obtained by the present invention has low birefringence, good impact resistance, and excellent transparency. Therefore, it can be used for many optical members such as a display panel plate, a liquid crystal panel plate, various lenses, a prism optical fiber, an optical filter, and an optical disk. In addition, the optical member with a transparent electrode obtained by the present invention has excellent adhesion to the surface of the cured product of the transparent conductive film and excellent transparency, so that it can be advantageously used for a display panel plate, a liquid crystal panel plate and the like.

[0041]

The following examples serve to illustrate the present invention more specifically. Parts in the examples indicate parts by weight. Various physical properties of the cured product described in the examples were measured by the following test methods. (1) Light transmittance The light curing rate at 500 nm was measured. (2) Birefringence The birefringence was measured at 25 ° C. using a birefringence measuring device (manufactured by Oak). (3) Heat resistance In the Vicat softening test, a sample in which the indenter penetrated 0.3 mm or more at 120 ° C. or less was evaluated as ×, and a sample that did not enter was evaluated as ○. Indenter cross-sectional area 1.0mm ² , load 5k
g, heating rate 50 ° C./Hr. (4) Flexural modulus 3 cm between fulcrum points for a 1 cm wide plate
cm at 25 ° C. using an autograph tester. (5) Impact resistance A 40 mm square plate was used as a sample, and 8 g of steel balls were dropped to a height of 10 using a falling ball tester (manufactured by Tokyo Seimitsu Co., Ltd.).
The sample is dropped from the position of cm to give an impact to the sample. The position where the steel ball is dropped is raised by 10 cm, and the ball is dropped repeatedly until it breaks. Falling ball impact strength = (falling ball height when sample is broken) −10 cm. (6) Demolding property The cured product having cracks when demolding was rated as x. (7) Oxygen Permeability According to ASTN D3985, using OX-TRAN100 of Modern Control, 23
It measured under the conditions of ° C-80% RH. (8) Resistance value Measured using Mitsubishi Chemical Loresta.

Example 1 Bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = 75 parts of dimethacrylate, 5 parts of pentaerythritol tetrakis (β-thiopropionate), bisphenol A bis [(Oxyethyl) ether] = 20 parts of dimethacrylate, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucillin TP” manufactured by BASF) as a photoinitiator
O "), 0.05 parts of benzophenone and 0.02 parts of benzophenone were uniformly stirred and mixed, followed by defoaming to obtain a composition. This composition was poured into a mold composed of two polished glass plates and a 1 mm thick silicon spacer, and placed between a metal halide lamp with an output of 80 W / cm above and below a distance of 40 cm from the glass surface for 5 minutes. Irradiated with ultraviolet light. After the ultraviolet irradiation, the mold was removed and heated at 120 ° C. for 1 hour to obtain a cured product. Various properties of the cured product were as shown in Table 1.

Example 2 75 parts of bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate, 5 parts of pentaerythritol tetrakis (β-thiopropionate), bisphenol A bis A cured product was obtained in the same manner as in Example 1 except that [(dioxyethyl) ether] = 20 parts of dimethacrylate was used. Various properties of the cured product were as shown in Table 1.

Example 3 bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = 75 parts of dimethacrylate, 5 parts of pentaerythritol tetrakis (β-thiopropionate), tetrabromobisphenol A bis [(oxyethyl) ether] = dimethacrylate 2
A cured product was obtained in the same manner as in Example 1 except that 0 part was used. Various properties of the cured product were as shown in Table 1.

Example 4 Bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = 75 parts of dimethacrylate, tris [2- (β-thiopropionyloxy)
Ethyl] triisocyanurate 5 parts, bisphenol A
A cured product was obtained in the same manner as in Example 1, except that 20 parts of bis [(oxyethyl) ether] = dimethacrylate was used. Various properties of the cured product were as shown in Table 1.

Example 5 On the cured product having a thickness of 1 mm obtained in Example 1, a sputtering device (Tokuda Seisakusho; type CFS) was used.
-4 ES) to form a 200 Å film of SiO ₂ . Various properties of the obtained sheet were as shown in Table 1. The oxygen permeability of the obtained sheet was 1 cc / m ^2.
・ It was 24 h · atm or less.

Example 6 On the cured product having a thickness of 1 mm obtained in Example 1, a sputtering apparatus (Tokuda Seisakusho; type CFS) was used.
-4 ES) to form an ITO film of 1500 angstroms. Various properties of the obtained sheet were as shown in Table 1. The sheet obtained had a surface resistance of 30 Ω / □.

Example 7 On the cured product having a thickness of 1 mm obtained in Example 1, a sputtering device (Tokuda Seisakusho; type CFS) was used.
-4 ES) to form a 200 angstrom film of SiO ₂ , and further apply ITO on the film by using the same apparatus at 1500 Å.
Angstrom was formed. Various properties of the obtained sheet were as shown in Table 1. The oxygen permeability of the obtained sheet was 1 cc / m ² · 24 h · atm or less, and the surface resistance was 30Ω / □.

Comparative Example 1 Using 100 parts of bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate, a mercapto compound and a bisphenol A skeleton di (meth) acrylate were compounded. Example 1
A cured product was obtained in the same manner as described above. Various properties of the cured product were as shown in Table 1.

Comparative Example 2 Using 95 parts of bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate and 5 parts of pentaerythritol tetrakis (β-thiopropionate), A cured product was obtained in the same manner as in Example 1 without blending bisphenol A skeleton di (meth) acrylate. Various properties of the cured product were as shown in Table 1.

Comparative Example 3 Bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = 60 parts of dimethacrylate, pentaerythritol tetrakis (β-thiopropionate), bisphenol A bis [( [Oxyethyl) ether] = cured product was obtained in the same manner as in Example 1 except that 20 parts of dimethacrylate was used. Various properties of the cured product were as shown in Table 1.

[0052]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02F 1/1333 500 G02F 1/1333 500

Claims (7)

[Claims] 1. A low birefringence optical member obtained by molding a resin composition containing the following components A, B, and C, followed by photopolymerization and curing. Component (A): 32 to 94.9 parts by weight of an alicyclic hydrocarbon skeleton bis (meth) acrylate represented by the following general formula [I]. Embedded image [R ¹ and R ² may be the same or different and each is hydrogen or CH ₃ , p is an integer of 1 or 2, q is 0 or 1] Component (B): [II], [III] and 0.1 to 8 parts by weight of at least one mercapto compound selected from [IV]. Embedded image [R ³ is -CH ₂ - or -CH ₂ CH ₂ - indicates, R ⁴
Is a C _2-15 hydrocarbon residue or an alkyl ether residue, and a is an integer of 2 to 6] [X is HS- (CH _2- ) _b (CO)-(OCH ₂ CH
_{2) d - (CH 2)} c - (b, d is an integer of 1 to 8, c is 0 to 2)] embedded image [R ⁵ is a hydrocarbon group which may contain oxygen, e is an integer of 2 or more] Component (C): 5 to 60 parts by weight of a bisphenol A skeleton bis (meth) acrylate represented by the following general formula [V]. Embedded image [R ^{6 to} R ⁹ may be the same or different, each may be hydrogen or CH ₃ or a halogen atom, R ¹⁰ and R ¹¹ may be the same or different, and each of hydrogen or CH ₃ , r and s is 0 to 7 and may be the same or different.] 2. The low birefringence optical member according to claim 1, wherein the low birefringence optical member is a plate for a liquid crystal display panel. 3. The low birefringence optical member according to claim 1, wherein a gas barrier film is formed on the surface of the resin composition molded body. 4. The low birefringence optical member according to claim 1, wherein a transparent electrode is formed on the surface of the resin composition molded body. 5. The low birefringence optical member according to claim 1, wherein a gas barrier film and a transparent electrode film are laminated on the surface of the resin composition molded body. 6. A resin composition for a low birefringence optical member, comprising the following components A, B, and C. Component (A): 32 to 94.9 parts by weight of an alicyclic hydrocarbon skeleton bis (meth) acrylate represented by the following general formula [I]. Embedded image [R ¹ and R ² may be the same or different and each is hydrogen or CH ₃ , p is an integer of 1 or 2, q is 0 or 1] Component (B): [II], [III] and 0.1 to 8 parts by weight of at least one mercapto compound selected from [IV]. Embedded image [R ³ is -CH ₂ - or -CH ₂ CH ₂ - indicates, R ⁴
Is a C _2-15 hydrocarbon residue or an alkyl ether residue, and a is an integer of 2 to 6] [X is HS- (CH _2- ) _b (CO)-(OCH ₂ CH
_{2) d - (CH 2)} c - (b, d is an integer of 1 to 8, c is 0 to 2)] embedded image [R ⁵ is a hydrocarbon group which may contain oxygen, e is an integer of 2 or more] Component (C): 5 to 60 parts by weight of a bisphenol A skeleton bis (meth) acrylate represented by the following general formula [V]. Embedded image [R ^{6 to} R ⁹ may be the same or different, and each of hydrogen or CH ₃ or a halogen atom, R ¹⁰ and R ¹¹ may be the same or different, and hydrogen or CH ₃ , r and s are each 0 to 7 and may be the same or different.] 7. Production of a low birefringence optical member characterized in that a resin composition containing the following components A, B and C is molded and photopolymerized and cured by irradiation with active energy rays. Method. Component (A): 32 to 94.9 parts by weight of an alicyclic hydrocarbon skeleton bis (meth) acrylate represented by the following general formula [I]. Embedded image [R ¹ and R ² may be the same or different and each is hydrogen or CH ₃ , p is an integer of 1 or 2, q is 0 or 1] Component (B): [II], [III] and 0.1 to 8 parts by weight of at least one mercapto compound selected from [IV]. Embedded image [R ³ is -CH ₂ - or -CH ₂ CH ₂ - indicates, R ⁴
Is a C _2-15 hydrocarbon residue or an alkyl ether residue, and a is an integer of 2 to 6] [X is HS- (CH _2- ) _b (CO)-(OCH ₂ CH
_{2) d - (CH 2)} c - (b, d is an integer of 1 to 8, c is 0 to 2)] embedded image [R ⁵ is a hydrocarbon group which may contain oxygen, e is an integer of 2 or more] Component (C): 5 to 60 parts by weight of a bisphenol A skeleton bis (meth) acrylate represented by the following general formula [V]. Embedded image [R ^{6 to} R ⁹ may be the same or different, each may be hydrogen or CH ₃ or a halogen atom, R ¹⁰ and R ¹¹ may be the same or different, and each of hydrogen or CH ₃ , r and s is 0 to 7 and may be the same or different.]