JP6346739B2 - Acrylate compound, acrylic resin composition and cured product thereof, and optical material - Google Patents

Description

  The present invention relates to an acrylic resin composition useful as an optical material having excellent high refractive index and low water absorption, transparency, and handling properties, and a cured product thereof. It is suitably used for various optical materials such as materials, protective films such as color filters for liquid crystals, protective coating materials for optical materials, fine particles for electronic paper and liquid crystal spacers, and adhesives for optical disks and optical fibers.

  Acrylic resins are used in a wide range of industrial applications. A typical field is an optical material. Recently, plastic has been actively used as a glass substitute material in the optical field, and a (meth) acrylic resin such as polymethyl methacrylate is well known as the material. In general, plastic materials typified by (meth) acrylic resins have light weight, safety, and design, but have a disadvantage that they are lower in refractive index than inorganic glass and easily become thick. Therefore, in recent years, there has been an increasing demand for plastic materials having a high refractive index. In particular, the advancement of high refractive index plastic materials to optical products has been remarkable, such as liquid crystal display panels, color filters, spectacle lenses, Fresnel lenses, lenticular lenses, prism lens sheets for TFT, aspheric lenses, optical disks, holograms, and optical fibers. Studies on optical waveguides and the like have been actively conducted.

  As a method of increasing the refractive index of the plastic material, it is necessary to increase the refractive index of the monomer that is the raw material of the plastic material. On the other hand, the property required for the glass substitute material is dimensional stability, The meth) acrylic resin has a drawback of having a large dimensional change rate due to water absorption, and a low water absorption is required. For that purpose, it is already well known that it is useful to introduce an aromatic ring into the molecular structure of the (meth) acrylic resin.

  As the above aromatic ring, a high refractive index material having a benzene ring, a naphthalene ring, or three or more polycyclic aromatics is known (Patent Documents 1, 2, etc.). However, when a benzene ring is used, the refractive index is not sufficient. Also, when an anthracene ring or fluorene ring, which is a polycyclic aromatic of 3 or more rings, is expected, a high refractive index is expected, but by increasing the absorption wavelength, not only photocuring properties but also transparency and weather resistance There is a problem that the solubility of the monomer is lowered.

  On the other hand, the refractive index of the naphthalene ring is higher than that of the monomer of the benzene ring. In addition, since polycyclic aromatics having 3 or more rings do not increase the absorption wavelength, there are advantages that there are few problems of reduction in photocurability, transparency, weather resistance, and monomer solubility.

  Since the advantages as described above are expected, acrylic resins having a naphthalene ring have been synthesized (Patent Documents 3 and 4). The acrylate compounds described therein are excellent in high refractive index, but have a melting point. Is not in the room temperature range, etc., it is not sufficient in terms of handling properties, which causes difficulties in industrial application to optical materials.

JP 05-170702 A JP 2004-083855 A JP 2010-285604 A JP 2011-084476 A

  Accordingly, it is an object of the present invention to provide an acrylic resin composition and a cured product thereof that provide an optical material that is excellent in high refractive index properties and has low water absorption, transparency, and handling properties.

（ここで、Ｘは水素原子又はメチル基を表し、Ｚ^１、Ｚ^２及びＺ^３はそれぞれ独立に、Ｃ１〜Ｃ３のアルキル基を表し、全てが同一でも異なっていてもよい。ａは０〜３の数を示し、ｂは０〜３の数を示し、ｃは０〜４の数を示すが、ａ、ｂ及びｃの合計は０〜２である。）
That is, this invention relates to the acrylate compound represented by following General formula (1).

(Here, X represents a hydrogen atom or a methyl group, Z ¹ , Z ² and Z ³ each independently represent a C1-C3 alkyl group, and all may be the same or different. The number of 3 is shown, b shows the number of 0-3, c shows the number of 0-4, but the sum of a, b, and c is 0-2. )

  Furthermore, the present invention is an acrylic resin composition comprising the acrylate compound and a polymerization initiator. The acrylic resin composition containing a bifunctional or higher polyfunctional acrylate compound gives a curable resin composition. Furthermore, the present invention is an acrylic resin cured product obtained by molding and curing the curable acrylic resin composition.

  The acrylic resin composition is excellent for an optical material. Moreover, this invention is an optical material characterized by consisting of said acrylic resin hardened | cured material.

  The acrylic resin composition containing the acrylate compound of the present invention is superior to conventional acrylic resin compositions in terms of high refractive index, low water absorption, transparency, and handling properties. Protective films such as color filters, optical material protective coating materials, fine particles for electronic paper and liquid crystal spacers, and optical materials such as adhesives for optical disks and optical fibers.

¹ H-NMR spectrum of acrylate compound 1b of the present invention is shown. ¹ H-NMR spectrum of acrylate compound 1c of the present invention is shown.

Hereinafter, the present invention will be described in detail.
The acrylic resin composition of the present invention comprises an acrylate compound represented by the general formula (1) and a polymerization initiator as essential components.

  The acrylate compound of the present invention is represented by the general formula (1). This acrylate compound has a naphthalene structure and a benzene structure linked by a flexible oxymethylene chain, and has an appropriate number of (meth) acryloyl groups per molecular weight, so it has excellent high refractive index and low water absorption. Gives a resin excellent in transparency and the like.

  In the general formula (1), X represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom from the viewpoint of photocurability as the resin composition.

In the general formula (1), Z ¹ , Z ² and Z ³ each independently represent a C1 to C3 alkyl group or a C1 to C3 alkoxy group, and they may all be the same or different. Good. Preferably, it is a C1-C3 alkyl group. a shows the number of 0-4, b shows the number of 0-3, c shows the number of 0-4. The melting point of this compound is preferably 100 ° C. or lower, more preferably 30 ° C. or lower, and thereby excellent handling properties are obtained. The melting point can be adjusted by changing Z ¹ , Z ² and Z ³ and a, b and c. From this viewpoint, the total of a, b, and c is preferably 0 to 3, and more preferably 0 to 2.

As an example, the acrylate compound represented by the general formula (1) is acrylated by reacting a chloromethylbenzyloxynaphthalene compound with acrylic acid or methacrylic acid (hereinafter collectively referred to as acrylic acids). Can be manufactured.
For example, a chloromethyl benzyloxy naphthalene compounds, expressed in NpOPh-CH ₂ -Cl, expressed acrylic acid with CH ₂ = CHX-COOH, occurs the following reaction formula.
NpOPhCH ₂ -Cl + CH ₂ = CHX-COOH = NpOPh-CH ₂ -O-CO-CHX = CH ₂ + HCl
Here, Np and Ph are a naphthyl group and a phenylene group, and may have a substituent Z ¹ , Z ² or Z ³ .

The chloromethylbenzyloxynaphthalene compound can be obtained, for example, by a method of reacting naphthols with bischloromethylbenzenes. In this case, the types of Z ¹ , Z ² and Z ³ in the general formula (1) are determined by the substituents of naphthols and bischloromethylbenzenes used as raw materials.

  The acrylate compound of the present invention is useful as a monomer for various resins, and gives a thermosetting resin when used in combination with a polyfunctional monomer. Since the resin obtained from the acrylate compound of the present invention has good optical properties such as transparency and refractive index, it is excellent as an optical material.

  The polymerization initiator contained in the acrylic resin composition of the present invention may be a known polymerization initiator used as a polymerization initiator for vinyl compounds, and polymerization (photopolymerization) by irradiation with active energy rays such as ultraviolet rays and electron beams. ) Or a polymerization initiator that initiates heat polymerization (thermal polymerization). Usually, a photopolymerization initiator is used for photopolymerization, and a radical polymerization initiator is used for thermal polymerization.

  When curing by ultraviolet irradiation, it is preferable to add a photopolymerization initiator to the resin composition in advance.

  Although it does not specifically limit as a photoinitiator, The normal photoinitiator of the type which generate | occur | produces a radical by being excited by ultraviolet irradiation is mentioned, Specifically, as a suitable initiator, Benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-iso-propyl ether, α-methylbenzoin, α-hydroxyisobutylphenone, benzophenone, p-methylbenzophenone, p-chlorobenzophenone, p-diethylaminobenzophenone, etc. Benzophenones, acetophenone, 1-hydroxycyclohexyl phenyl ketone, 9,10-anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone and other anthraquinones, diphenyl disulfide, tetramethylthiuramdisulfur Examples thereof include sulfur-containing compounds such as fido.

  Moreover, in order to accelerate the photopolymerization reaction by the photopolymerization initiator, a photosensitizer may be added. The photosensitizer is not particularly limited. Specifically, tertiary amines such as triethylamine and triethanolamine, alkylphosphines such as triphenylphosphine, thioethers such as thiodiglycol, and the like. Illustratively, the blending amount is recommended to be about 0.01 to 5% by weight with respect to the total amount of the polymerizable compound.

  As the ultraviolet light source, a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like is used.

  In the case of curing with an electron beam, it is not necessary to use a photosensitizer, and an electron beam with a dose of about 1 to 20 megarads is usually irradiated with a general-purpose electron beam generator.

  The radical polymerization initiator is not particularly limited, and specific examples include peroxides such as benzoyl peroxide, diisopropyl peroxycarbonate, lauroyl peroxide, and azo compounds such as azobisisobutyronitrile. These polymerization initiators may be used alone or in combination of two or more.

  As the polymerization initiator, it is preferable to use one for thermal polymerization and one for photopolymerization depending on the application.

  The amount of these polymerization initiators used varies depending on whether or not a polymerization inhibitor is used and the type and amount of the polymerization inhibitor used, but is 0.001 to 5 with respect to 100 parts by weight of the total amount of polymerizable compounds. It is good that it is 0.01-5 weight part, More preferably, it is 0.01-5 weight part, More preferably, it is 0.01-1 weight part. However, since the amount used varies greatly depending on the type of polymerization initiator used, it is necessary to appropriately determine the optimum conditions.

  A known polymerization inhibitor can be added to the acrylic resin composition of the present invention for storage of the resin composition. However, since the type and the amount added vary greatly depending on the type and amount of the polymerization initiator used and the following polymerizable monomer, it is necessary to appropriately determine the optimum conditions.

  Moreover, in the acrylic resin composition of this invention, other acrylates other than the acrylate compound represented by General formula (1) can be included as needed. Furthermore, polymerizable monomers (hereinafter referred to as other polymerizable monomers) that undergo radical polymerization with heat or light other than acrylate can be added.

  As these other acrylates, known acrylates by heat or light may be used, and acrylates such as monofunctional (meth) acrylates, polyfunctional (meth) acrylates, and acrylic polymerizable oligomers are preferably mentioned. In order to give a curable resin composition, a polyfunctional (meth) acrylate is preferably mentioned, and other polymerizable monomers (which may be monofunctional monomers) can be included as necessary.

  Monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, butyl (meth) acrylate, iso-butyl (meth) acrylate, and n-hexyl (meth). Acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Examples include acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and 2,3-dibromopropyl (meth) acrylate. It is.

  Bifunctional (meth) acrylates include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. , Propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, propanediol di (meth) acrylate, glycerin di (meth) acrylate, Dicyclopentanyl diacrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pen Diol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, bis (oxymethyl) tricyclo [5.2.2.02,5] decanedi (meth) acrylate, Cyclohexanediol di (meth) acrylate, bis [(meth) acryloxymethyl] cyclohexane, acetal diacrylate of trimethylolpropane and pivalaldehyde, hydroxypivalic acid neopentyl glycol ester diacrylate, bisphenol A-di (meth) Examples include acrylate, di (meth) acrylate of bisphenol A alkylene oxide adduct, and the like.

  Examples of tri- to tetrafunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. The

  Acrylic polymerizable oligomers include epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polybutadiene oligomer (meth) acrylate, polyamide-type (meth) acryl oligomer, melamine (meth) acrylate, cyclopentadiene Examples include oligomeric (meth) acrylates and silicone oligomer (meth) acrylates.

  The other polymerizable monomer is a monomer other than acrylate, such as styrene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, vinyl ether, acrolein, divinylbenzene and other vinyl compounds, ethylene, butadiene and the like. An α-olefin or the like can be used in combination as appropriate.

  These other polymerizable monomers may be used alone or in combination of two or more. As the polymerizable monomer by heat or light, it is preferable to use either a thermally polymerizable monomer or a photopolymerizable monomer depending on the application.

Particularly preferred other acrylates and particularly preferred other polymerizable monomers are polyfunctional unsaturated compounds having two or more unsaturated bonds capable of radical copolymerization. Preferably, it is a compound represented by the following general formula (2). And it is high refractive index and low water absorption that 1-100 weight% of the monomers (a polymerizable oligomer etc. are included) in an acrylic resin composition is a compound represented by General formula (2). This is suitable for giving a cured acrylic resin.
X (-A) n (2)

  In the general formula (2), X is a ring-containing group having 2 to 7, preferably 2 to 5, 5- or 6-membered rings. The plurality of rings of the ring-containing group are a) those in which the rings are directly bonded by a single bond, and b) the rings are bonded to each other through any of an alkylene group having 3 or less carbon atoms, an ether group, or a thioether group. Or c) that the rings are condensed, and may have two or more types of bonds a, b and c.

  Illustrative examples of X include n-valent groups having a cyclic structure as shown in the following formulas (3) to (19). In the compound represented by the general formula (2), n atomic groups A are substituted on these cyclic structures. These cyclic structures may further have a substituent.

  The n-valent groups having the structures of the above formulas (3) to (13) are preferable in terms of improving the high refractive index obtained from the acrylic resin composition of the present invention, and the above formulas (14) to (19). The n-valent group having the structure is preferable in terms of improving the low water absorption.

In the general formula (2), A represents —CH═CH ₂ , —CH ₂ OCOCH═CH ₂ , —CH ₂ OCOC (CH ₃ ) ═CH ₂ , —O (CH ₂ O) mCOCH═CH ₂ , or —O (CH ₂ O) mCOC (CH ₃ ) ═A group represented by CH ₂ . Preferably, it is a (meth) acrylate containing group. When A is —CH ₂ OCOCH═CH ₂ and —CH ₂ OCOC (CH ₃ ) ═CH ₂ , it corresponds to another acrylate, and the other corresponds to another polymerizable monomer. m is an integer of 0-4. Moreover, in General formula (2), although n is an integer of 2-4, the compound whose n is 2 is still more suitable from the ease of acquisition of material.
Further preferred other acrylates include acrylates having an aliphatic ring such as dicyclopentanyl diacrylate. An acrylate having an aliphatic ring such as dicyclopentanyl diacrylate generally has a low viscosity and is also suitable as a reactive diluent for reducing the viscosity. Orthophenylphenoxyethyl acrylate sold under the trade name “Miramar M1142” manufactured by MIWON is also suitable as a reactive diluent for reducing the viscosity.

  The type and amount of the other polymerizable monomer can be appropriately determined depending on the type and amount of the other constituents in the acrylic resin composition. Preferably, in order to obtain a sufficient effect, The proportion of the resin component (including monomer) is 5% by weight, preferably 10% by weight or more. However, 60% by weight or less is preferable. In particular, when a curable resin composition is used, it is desirable to blend about 10 to 60% by weight of a polyfunctional acrylate compound.

  Other components such as a filler, fiber, coupling agent, flame retardant, mold release agent, and foaming agent can be added to the acrylic resin composition of the present invention as necessary. Examples of the filler include polyethylene powder, polypropylene powder, quartz, silica, silicate, calcium carbonate, magnesium carbonate, gypsum, bentonite, fluorite, titanium dioxide, carbon black, graphite, iron oxide, aluminum powder, iron Examples include powder, talc, mica, kaolin clay and the like. Examples of the fibers include cellulose fibers, glass fibers, carbon fibers, and aramid fibers. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. Examples of the flame retardant include brominated bisphenol A, antimony trioxide, and phosphorus compounds. Examples of the mold release agent include stearates, silicones, waxes and the like. Examples of the blowing agent include CFC, dichloroethane, butane, pentane, dinitropentamethylenetetramine, p-toluenesulfonyl hydrazide, or CFC, dichloroethane, butane, pentane, and the like. Examples thereof include expandable thermoplastic resin particles filled in an acrylic ester copolymer shell.

  The acrylic resin composition of the present invention can be easily made into a thermoplastic or thermosetting acrylic resin cured product or molded article by a method similar to a conventionally known method. For example, a polymerization initiator, a polyfunctional polymerizable monomer, if necessary, other polymerizable monomer by heat or light, and other additives are added to the acrylate compound of the present invention using an extruder, kneader, roll, stirrer, etc. Mix well until uniform to obtain an acrylic resin composition, mold the acrylic resin composition using a roll coater, a cast after casting or a transfer molding machine, and then heat or irradiate at 80 to 200 ° C. By doing so, a cured acrylic resin can be obtained.

  Further, when the acrylic resin composition of the present invention is a curable acrylic resin composition, it is dissolved in a solvent and impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. It is also possible to obtain a cured product by hot press molding the prepreg obtained by heating and drying. For example, the acrylic resin composition of the present invention and other additives are heated and stirred until they are uniform, impregnated into a glass cloth, heated and semi-dried, and the solvent content is removed. A glass cloth laminate can be produced by heating and pressing at 200 ° C. for 1 hour or longer. However, when the optical material of the present invention is used for an application of transmitting light, the substrate is preferably a transparent material. On the other hand, when the optical material of the present invention is used for the purpose of reflecting / diffusing light, it is preferable that the base material is opaque with respect to the wavelength of the light to be reflected / diffused.

Moreover, the acrylic resin composition of the present invention can be used by dissolving in a solvent. At this time, as specific examples of the diluent solvent that can be used, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, and the like are preferable, and the amount used is based on the total weight of the acrylic resin composition and the diluent solvent. It is 10 to 70% by weight, preferably 15 to 65% by weight.
Moreover, the other acrylate of low viscosity or the other polymerizable monomer of low viscosity can also be used as a reactive diluent for reducing the viscosity of an acrylic resin composition. Here, the low viscosity is 500 cp or less, and preferably 200 cp or less. The amount of the reactive diluent used is equal to or less than the equivalent weight of the acrylate represented by the general formula (1), preferably 50% by weight.

  The acrylic resin cured product thus obtained is excellent in high refractive index, and gives an optical material excellent in low water absorption and transparency. Optical materials include glass substitute materials for lens applications, protective films for liquid crystal color filters, optical material protective coating materials, fine particles for electronic paper, liquid crystal spacers, optical disks, optical fiber adhesives, etc. It is suitably used for various optical materials.

  The optical material as used in the present invention means a material used for light transmitting or reflecting light, and is preferably an optical material for light transmission such as for lenses and light transmission films. More preferably, it is an optical material for lens use.

  Next, in order to further clarify the present invention, examples will be specifically described. In the text, “part” and “%” all indicate weight standards.

Synthesis example 1
In a 1000 ml four-necked flask equipped with a nitrogen blowing tube, a condenser, a dropping funnel, and a thermometer, 291.1 g of dimethylformamide and 50.9 g of 1,4-bis (chloromethyl) benzene were placed. Stir at 30 ° C. to dissolve. In a dropping funnel, 211.4 g of dimethylformamide in which 11.2 g of sodium hydroxide and 42.0 g of 2-naphthol were dissolved was added dropwise over 2 hours while stirring at 30 ° C. in a nitrogen atmosphere. did. After completion of dropping, the reaction was allowed to proceed for 3 hours.
After completion of the reaction, filtration was performed to remove insoluble matters, and then dimethylformaldehyde was distilled off under reduced pressure at 50 ° C. 400 g of chloroform was added and dissolved in the reaction mixture after distillation, and then 200 g of distilled water was added and washed with water. After liquid separation and separation of the chloroform phase, chloroform was distilled off under reduced pressure at 50 ° C. to obtain a crude crystal of precursor 1.
The crystals were washed with cold methanol to obtain 39.9 g of 2- (4-chloromethyl) benzyloxy-naphthalene (Precursor 1).

A 500 ml four-necked flask equipped with an air blowing tube, a condenser, an exhaust tube, and a thermometer is charged with 245 g of dimethylformamide, 8.7 g of anhydrous potassium carbonate, 0.006 g of methylhydroquinone and 28.9 g of precursor 1. The mixture was heated to 50 ° C. while blowing air, and 9.5 g of acrylic acid was added dropwise over 120 minutes. After completion of the dropwise addition, the mixture was reacted at 70 ° C. for 2 hours.
After completion of the reaction, insoluble matter was filtered off. Dimethylformaldehyde was distilled off at 60 ° C. under reduced pressure, and 300 g of toluene was added and dissolved. 200 g of distilled water was added and washed with water. After liquid separation and separation of the chloroform phase, chloroform was distilled off under reduced pressure at 50 ° C., and crude crystals of 2- (4-acryloxymethyl) benzyloxy-naphthalene (compound 1b) represented by the formula (1b) Got.

The crude crystals were washed with cold methanol to obtain 21.7 g of purified compound 1b (white crystals). The structure of the obtained compound 1b was identified by melting point measurement and ¹ H-NMR measurement. The melting point was 87 ° C. The ¹ H-NMR spectrum of compound 1b is shown in FIG.

Synthesis example 2

In Synthesis Example 1, synthesis was carried out in the same manner as in Synthesis Example 1 except that 1,3-bis (chloromethyl) benzene was used instead of 1,4-bis (chloromethyl) benzene. .3 g of 2- (3-acryloxymethyl) benzyloxy-naphthalene (compound 1c) represented by the formula (1c) was obtained.
The ¹ H-NMR spectrum of compound 1c is shown in FIG.

Example 1
50 parts by weight of the compound 1b obtained in Synthesis Example 1, 50 parts by weight of EO (ethylene oxide) modified bisphenol A diacrylate (FA-324A, manufactured by Hitachi Chemical Co., Ltd.), 1 part by weight as a photopolymerization initiator 1-hydroxycyclohexyl phenyl ketone and 0.5 parts by weight of perhexa 25B as a thermal polymerization initiator were mixed to obtain an acrylic resin composition A-1. This acrylic resin composition A-1 was cast (cast) to a thickness of 1.0 mm using a roll coater, and an accumulated exposure amount of 5400 mJ / cm ² using a 70 mW / cm high-pressure mercury lamp. And cured. Furthermore, heat curing was carried out in an oven to obtain a sheet-like acrylic resin cured product B-1.

Example 2
An acrylic resin cured product B-2 was obtained in the same manner as in Example 1 except that Compound 1c obtained in Synthesis Example 2 was used instead of Compound 1b.

Comparative Example 1
An acrylic resin cured product B-3 was obtained in the same manner as in Example 1 by using o-phenylphenol acrylate (MIWONER MIRAMER M1142, colorless liquid) instead of Compound 1b.

Next, the obtained acrylic resin hardened | cured material B-1, B-2, and B-3 were analyzed for the refractive index and water absorption rate as a sample of length 20mm and width 5mm.
The refractive index was measured using an Abbe refractometer at 25 ° C. and a light source wavelength of 589 nm.
The water absorption was calculated from the weight of the sheet before and after being immersed in water for 24 hours.
These results are shown in Table 1.

  As described above, the acrylic resin composition of the present invention and its cured product are excellent in high refractive index properties and low water absorption.

Claims (6)

An acrylate compound represented by the following general formula (1).

(Here, X represents a hydrogen atom or a methyl group, Z ¹ , Z ² and Z ³ each independently represent a C1-C3 alkyl group, and all may be the same or different. The number of 3 is shown, b shows the number of 0-3, c shows the number of 0-4, but the sum of a, b, and c is 0-2.)
  An acrylic resin composition comprising the acrylate compound according to claim 1 and a polymerization initiator.   The acrylic resin composition according to claim 2, comprising a bifunctional or higher polyfunctional acrylate compound.   A cured acrylic resin obtained by molding and curing the acrylic resin composition according to claim 3.   The acrylic resin composition according to claim 2 or 3, wherein the acrylic resin composition is used for an optical material.   An optical material comprising the cured acrylic resin according to claim 4.

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