KR102174272B1 - Polyfunctional (meth)acrylic acid ester copolymer, and curable resin composition and cured product thereof - Google Patents

Abstract

Provides a polyfunctional (meth)acrylic acid ester copolymer that has excellent optical properties, does not deteriorate adhesion to inorganic materials even under long-term moist and heat conditions, and maintains high optical properties, and a curable resin composition obtained by blending the same. .
Monofunctional (meth)acrylic acid ester (a) formed from (meth)acrylic acid and an alcohol having 9 to 30 carbon atoms, and a bifunctional (meth) represented by CH ₂ =CR-CO-OR ₂ -O-OC-CR=CH ₂ It is a copolymer obtained by copolymerizing acrylic acid ester (b) and monomers containing 2,4-diphenyl-4-methyl-1-pentene (c), and is a reactive (meta) derived from (b) in the side chain. ) A polyfunctional (meth)acrylic acid ester copolymer having an acrylate group at its terminal and a structural unit derived from (c), and soluble in a solvent such as toluene.

Description

Polyfunctional (meth)acrylic acid ester copolymer, curable resin composition, and cured product thereof {POLYFUNCTIONAL (METH)ACRYLIC ACID ESTER COPOLYMER, AND CURABLE RESIN COMPOSITION AND CURED PRODUCT THEREOF}

The present invention has excellent optical properties such as optical isotropy and high light transmittance, heat resistance, and processability, and has improved heat resistance and adhesion to inorganic materials under strict practical use conditions such as moist heat conditions, and It relates to the cured product.

Most of the monomers having reactive unsaturated bonds can produce a multimer by selecting a catalyst that causes a chain reaction by cleaving the unsaturated bonds and appropriate reaction conditions. In general, since the types of monomers having unsaturated bonds are very diverse, the abundance of the types of resins that can be obtained is also remarkable. However, there are relatively few types of monomers that can obtain a high molecular weight of 10,000 or more, generally referred to as a high molecular compound. For example, ethylene, substituted ethylene, propylene, substituted propylene, styrene, alkylstyrene, alkoxystyrene, norbornene, various acrylic esters, butadiene, isoprene, maleic anhydride, maleimide, fumaric acid ester, allyl compounds, etc. are representative monomers. Can be lifted. A wide variety of resins are synthesized by using these monomers alone or by copolymerizing them.

The uses of these resins are mainly limited to the field of relatively inexpensive consumer devices, and there are few applications in the field of advanced technology that require high heat resistance, dimensional stability, and microprocessing in the field of optoelectronic materials. The reason is that the polymer synthesized from the above monomers is usually thermoplastic, and since it is necessary to make a high molecular weight material to satisfy the mechanical properties, properties required in high-tech fields such as heat resistance and microprocessing are sacrificed. Can be mentioned.

On the other hand, the curable resin composition is useful, for example, as a material for mechanical parts, materials for electrical and electronic parts, materials for automobile parts, materials for civil engineering and construction, and materials for molding, and is also used as a material for paint or adhesive. In addition, when a hybrid member is combined with an inorganic substrate, not only can the thermal expansion coefficient be reduced, but also the appearance of the resin composition and the cured product can be controlled by matching the refractive index of the inorganic material and the resin, and transparency can be expressed. ㆍEspecially useful as a material for electronic parts and optical applications. For example, digital camera modules are being mounted on mobile phones, and thus miniaturization is in progress, and cost reduction is also required. In addition, as a new application, the need for in-vehicle cameras and barcode readers for courier companies is increasing. When applied to these applications, not only the heat resistance during solder reflow during manufacturing is required, but also high reliability such as long-term heat resistance and low water absorption is considered in consideration of the high temperature exposure in summer during actual use. Is required.

As a method of solving the drawbacks of such a vinyl-based thermoplastic polymer, Patent Documents 1 to 3 disclose polymers having a (meth)acryloyl group or a vinyl ether group in the pendant. For example, Patent Document 1 discloses a photosensitive composition comprising a (meth)acryloyl group pendant type polymer and a photopolymerization initiator obtained by cationic polymerization of a heteropolymerizable monomer such as 2-vinyloxyethyl acrylate (VEA). . Further, Patent Document 2 discloses a photosensitive composition comprising a pendant (meth)acryloyl group polymer, a compound having a photoreactive unsaturated carboxyl group, and a photopolymerization initiator. In addition, in Patent Document 3, a heteropolymerizable monomer such as 2-vinyloxyethyl acrylate (VEA) is used in a carboxylic acid ester solvent compound having a photoreactive unsaturated group inert to cationic polymerization itself, using a cationic polymerization catalyst. A production method for obtaining a polymer solution by homopolymerization or copolymerization is disclosed.

However, when using a reactive polymer prepared according to the technology using heteropolymerizable monomers disclosed therein, it has a balance of properties such as processability, heat resistance, and high transparency required in the field of advanced optical applications. A polymer and curable resin composition having improved optical properties and adhesion to inorganic materials under actual use conditions could not be obtained.

On the other hand, in Patent Document 4, a monovinyl aromatic compound and a bifunctional (meth)acrylic acid ester can be copolymerized to obtain a reactive (meth)acrylate derived from a bifunctional (meth)acrylic acid ester in the side chain. A soluble polyfunctional vinyl aromatic copolymer having a structural unit containing a group is disclosed. However, the soluble polyfunctional vinyl aromatic copolymer obtained by the technology disclosed therein has excellent thermal decomposition resistance even against thermal history at high temperature, has a reactive (meth)acrylate group in the side chain, has excellent processability, and has solvent solubility. However, it was a material that had limitations in practical use that it could not be used for optical lenses for low color dispersion applications, and the adhesion to inorganic materials was not improved.

In addition, Patent Document 5 discloses a composition containing 1 to 25% by weight of di(meth)acrylate, which is a linear aliphatic dihydric alcohol having 4 to 8 carbon atoms as a constituent in a methyl methacrylate (MMA) syrup. Has been. And the preparation of the MMA syrup composition disclosed therein is to use MMA, or MMA and a vinyl copolymer capable of copolymerizing with it, and a chain-transfer agent in the presence of a polymerization initiator, in the presence of an inert gas (e.g. For example, N ₂ gas) In an atmosphere, it is disclosed to perform polymerization at room temperature or by heating. And specifically exemplified as the chain transfer agent is only ionic compounds such as lauryl mercaptan, thioglycolate octyl ester, thiocresol, thionaphthol, and benzyl mercaptan, and 2,4-diphenyl-4-methyl-1- About pentene, it was not specifically disclosed. In addition, the coexistence of a terminal group derived from 2,4-diphenyl-4-methyl-1-pentene and a structural unit derived from a monofunctional (meth)acrylic acid ester synergistically prevents the occurrence of refractive index branching during moist heat. What could be suppressed wasn't even being suggested. In addition, the composition obtained by the technology disclosed therein did not have improved adhesion to inorganic materials under strict practical use conditions such as moist heat conditions.

In addition, Patent Document 6 discloses a polymerizable composition consisting of a vinyl monomer and a di(meth)acrylate compound, and the use of 2,4-diphenyl-4-methyl-1-pentene is also disclosed, but the amount used Is used as a common chain transfer agent in the amount of a few percent of comma, and the product was also crosslinked and gelled, and did not show solvent solubility.

In addition, Patent Document 7 includes a structural unit consisting of 1) an epoxy group-containing (meth)acrylate, 2) a hydroxyl group-containing (meth)acrylate, 3) (meth)acrylic acid, and 4) an aromatic group-containing (meth)acrylate. A heat changeable resin composition for a color filter comprising a self-curing copolymer and an organic solvent is disclosed. And the self-curing copolymer obtainable by the technology disclosed therein, in order to achieve a range of a preferable molecular weight in the polymerization step, mercaptopropionic acid, mercaptopropionic acid ester, thioglycol, thioglycerin, dodecylmercaptan, α -It is said that known molecular weight modifiers such as methyl styrene dimer can be used. However, in the techniques disclosed therein, since a bifunctional or higher vinyl compound having a plurality of vinyl groups is not added during polymerization, only one or less terminal groups derived from molecular weight modifiers can be introduced into the polymer chain, and the function derived from the terminal groups There was a flaw in that it could not be given enough. In addition, the self-curing copolymer obtainable by this technology forms a heat-changeable resin composition in a resin composition with an epoxy resin, but since no curing reaction occurs between the acrylate resin, the strength and heat resistance of the blended resin composition There was also a drawback that it caused a deterioration.

In order to solve these problems, Patent Document 8 discloses a soluble polyfunctional (meth)acrylic acid ester copolymer having an alicyclic structure. However, the disclosed technology has a drawback that adhesion with inorganic materials is deteriorated in a long-term reliability test under high temperature and high humidity conditions.

Therefore, it has excellent optical properties such as optical isotropy and high light transmittance, has a balance of properties such as easy processability and heat resistance, and has optical properties, heat resistance and inorganic materials under strict practical conditions such as long-term moist heat conditions. Curable resin compositions having improved adhesion have not existed so far.

Japanese Patent Publication No. 49-13212 Japanese Patent Publication No. 51-34433 Japanese Patent Publication No. 54-27394 Japanese Patent Application Publication No. 2008-247978 Japanese Patent Application Publication No. 57-167340 Japanese Patent Application Publication No. 2002-121228 Japanese Patent Application Publication No. 2009-1770 Japanese Patent Application Publication No. 2011-127008

The present invention has excellent optical properties such as optical isotropy and high light transmittance, has excellent balance of various properties required for optical materials in advanced technical fields such as workability and heat resistance, and under strict practical use conditions such as long-term moist and heat conditions. In addition, a novel polyfunctional (meth)acrylic acid ester copolymer having a controlled molecular weight distribution and solvent solubility without deterioration in adhesion to inorganic materials, maintaining high optical properties, and the copolymer, and a mixture thereof It aims at providing a curable resin composition.

The present invention is the following general formula (1)

(In the formula, R ₁ is a linear or branched hydrocarbon group having 9 to 30 carbon atoms, and an oxygen atom, a sulfur atom, or a nitrogen-containing group may be contained in the hydrocarbon group. R is H or a methyl group.)

Monofunctional (meth)acrylic acid ester (a) represented by,

The following general formula (2)

(In the formula, R ₂ is a hydrocarbon group having 2 or more and 30 or less carbon atoms, and an oxygen atom, a sulfur atom, or a nitrogen-containing group may be contained in the hydrocarbon group. R is H or a methyl group.)

A bifunctional (meth)acrylic acid ester (b) represented by,

It is a copolymer obtained by copolymerizing monomers containing 2,4-diphenyl-4-methyl-1-pentene (c),

A copolymer having a reactive (meth)acrylate group derived from a bifunctional (meth)acrylic acid ester (b) in the side chain and a structural unit derived from 2,4-diphenyl-4-methyl-1-pentene (c) at the terminal As a coalescence, the weight average molecular weight is 10,000 to 1,000,000, and the molar fraction Mb which is the unit derived from the component (b) among all the acrylic acid ester units is the unit derived from the monofunctional (meth)acrylic acid ester (a), and the bifunctional (meth) ) When the introduced amount (mol) of the unit derived from the acrylic ester (b) is a and b, respectively, it is 0.01 to 0.5 as b/(a+b), and toluene, xylene, propylene glycol monomethyl ether acetate, tetra It is a polyfunctional (meth)acrylic acid ester copolymer soluble in hydrofuran, dichloroethane or chloroform.

In addition, in the present invention, in the general formula (1), R ₁ is a linear or branched fatty chain having 9 to 30 carbon atoms, or an ethylene glycol chain, or in general formula (2), R ₂ is carbon It is the polyfunctional (meth)acrylic acid ester copolymer described above, which satisfies any one or more of a linear fatty chain having a number of 2 or more and 30 or less or an ethylene glycol chain.

In addition, in the present invention, when the introduced amount (mol) of the reactive (meth)acrylate group-containing unit derived from the bifunctional (meth)acrylic acid ester (b) is b1, the molar fraction Mb1 of the unit is b1/(a+b). Then, when the amount (mol) of the unit derived from 0.02 to 0.5 or 2,4-diphenyl-4-methyl-1-pentene (c) is c, the mole fraction Mc of the unit is c/(a+ It is the polyfunctional (meth)acrylic acid ester copolymer described above, which satisfies any one or more of 0.005 to 0.3 as b+c).

Further, the present invention is a curable resin composition comprising the above polyfunctional (meth)acrylic acid ester copolymer, a monomer having at least one functional group having an unsaturated double bond, and an initiator, and the curable resin composition It is an optical article that can be obtained by curing and molding.

According to the present invention, it has excellent optical properties such as optical isotropy and high light transmittance, and has excellent balance of various properties required for engineering members such as optical lenses, prisms, and adhesive materials in advanced technology fields such as low water absorption, processability, and heat resistance. In addition, it is possible to provide a curable resin composition having improved optical properties and adhesion to inorganic materials under stringent practical use conditions such as long-term moist heat conditions.

Hereinafter, the polyfunctional (meth)acrylic acid ester copolymer and the curable resin composition of the present invention will be described in detail.

The polyfunctional (meth)acrylic acid ester copolymer (hereinafter, sometimes abbreviated as a copolymer) of the present invention includes a monofunctional (meth)acrylic acid ester (a), and a bifunctional (meth)acrylic acid ester (b). It is a copolymer obtained by copolymerization of the monomer and 2,4-diphenyl-4-methyl-1-pentene (c), and is a reactive polymer derived from a bifunctional (meth)acrylic acid ester (b) in the side chain. It is a soluble polyfunctional (meth)acrylic acid ester copolymer having a (meth)acrylate group and having a structural unit derived from 2,4-diphenyl-4-methyl-1-pentene (c) at the terminal. Here, soluble means soluble in toluene, xylene, propylene glycol monomethyl ether acetate (PGMEA), tetrahydrofuran, dichloroethane or chloroform. The solubility test is made under the conditions shown in the examples. Further, monofunctional (meth)acrylic acid ester (a) as a component (a), bifunctional (meth)acrylic acid ester (b) as a component (b), and 2,4-diphenyl-4-methyl-1-pentene (c ) Is also referred to as (c) component or DMP.

Since the copolymer can be obtained by copolymerizing a monofunctional (meth)acrylic acid ester and a bifunctional (meth)acrylic acid ester, it has a branched structure or a crosslinked structure, but the amount of such a structure is limited to the extent that it indicates solubility. Accordingly, it is a copolymer having a structural unit (b1) containing an unreacted (meth)acrylic group derived from a bifunctional (meth)acrylic acid ester (b) in the side chain. This unreacted (meth)acrylic group is also referred to as a pendant (meth)acrylic group, and in order to exhibit polymerizable properties, it is further polymerized by polymerization treatment, and a solvent-insoluble cured resin can be provided.

Further, the copolymer has a structural unit derived from the component (c) at the terminal. By introducing this structural unit to the terminal of the copolymer, it becomes possible to obtain a cured product with improved molding processability such as releasability.

The copolymer has a structural unit (a) derived from the component (a), a unit (b) derived from the component (b), and a structural unit (c) derived from the component (c). Here, in the structural unit (b) derived from the component (b), both of the polymerizable double bonds (referred to as vinyl groups) contained in the two (meth)acrylic acid esters are involved in polymerization, and a branched structure or a crosslinked structure There is a structural unit (b2) that forms a structural unit (b2) and a structural unit (b1) containing an unreacted (meth)acrylic group in which only one vinyl group is involved in polymerization and the other vinyl group remains unreacted. (c) DMP as a component acts as a chain transfer agent to prevent an increase in molecular weight, and is present at the end of the copolymer. Releasability and low water absorption can be improved by introducing the structural unit derived from the component (c) into the above range at the terminal of the polymer. (c) component is included in monomers together with (a)-(b) components.

The amounts (mol) of the structural units (a), (b), (c), (b1) and (b2) introduced into the copolymer are represented by a, b, c, b1 and b2, respectively, and their mole fractions are respectively Denoted by Ma, Mb, Mc, Mb1 and Mb2.

The amount of the (c) component introduced to the copolymer is 0.005 to 0.3, preferably 0.01 to 0.25, and particularly preferably 0.03 to 0.15 as the molar fraction Mc represented by the following formula (4).

The monofunctional (meth)acrylic acid ester (a) is important in order to improve the solvent solubility, low water absorption, heat resistance, optical properties and processability of the copolymer, and is particularly important for adhesion in a long-term moist heat test. As such monofunctional (meth)acrylic acid ester (a), a compound represented by General Formula (1) is used. In the formula, R ₁ is a hydrocarbon group having 9 or more and 30 or less carbon atoms, and is a structure in which heteroatoms or groups such as an oxygen atom, a nitrogen-containing group, and a sulfur atom may exist in the hydrocarbon group. In the case of a structure in which heteroatoms or groups may be present, it is advantageously a structure in which these heteroatoms or groups exist between carbon-carbon bonds constituting this hydrocarbon group. For example, it is a structure in which an oxygen atom or a sulfur atom exists as an ether bond or a thioether bond. Further, examples of the nitrogen-containing group include an amide group and an imide group.

As R ₁ , a (meth)acrylic acid ester which is an aliphatic chain having a C9 or more and 30 or less linear or partially branched structure, or an ethylene glycol chain is preferable. Preferably, the alkylene chain represented by C _n H _2n , the ethylene oxide chain represented by (C ₂ H ₄ O) _n (n is a number of 1 or more), or a structure in which the alkylene chain and the ethylene oxide chain are bonded. In this case, H is bonded to one end. When the number of carbon atoms is 9 or more, the elastic modulus of the copolymer decreases, and the proportion of the hydrocarbon group to the polar group increases, resulting in a copolymer having excellent water resistance. In addition, as it is a linear, partially branched structure, the elastic modulus is lowered and adhesion is improved. In addition, the introduction of an ethylene glycol chain is preferable because flexibility is improved. Specifically, 2-ethylhexyl EO-modified (n≒2) (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, methoxypolyethylene glycol #400 acrylate (Shinnakamura Kagaku Kyōgo Co., Ltd.), methoxy polyethylene glycol #550 acrylate (Shin-Nakamura Chemical Co., Ltd.) and the like are preferred, and among these, 2-ethylhexyl EO modified (n ≒ 2) ( It is particularly preferable to have both a fatty chain and an ethylene glycol chain typified by meth)acrylate.

Further, as the monofunctional (meth)acrylic acid ester, in addition to the chain acrylic acid ester, other monofunctional (meth)acrylic acid ester (d) components may be used in combination. Thereby, other physical properties can be adjusted. Particularly, (meth)acrylic acid ester having a ring structure is preferable because heat resistance, elastic modulus, solubility, refractive index, etc. can be adjusted according to the application. As monofunctional (meth)acrylic acid esters having a ring structure, specifically, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy Ethyl (meth) acrylate, and dicyclopentanyloxyethyl (meth) acrylate, phenoxy polyethylene glycol acrylate, ethoxylated o-phenylphenol acrylate, and nonylphenol EO adduct acrylate.

In addition, monofunctional (meth)acrylates having 8 or less carbon atoms may be used in combination, and examples of these (meth)acrylates include methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate. , 2-methylhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, etc. are mentioned. In addition, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (Meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and partially ethoxylated 2-hydroxy (meth)acrylate, etc. may also be used, but preferably methyl methacrylate, n-butyl acrylate and It is 2-hydroxyethyl methacrylate. These low molecular weight (meth)acrylic acid ester monomers may be used alone or in combination of two or more.

Structural units derived from these other monofunctional components (d) are preferably within the range of 60 mol% or less, particularly preferably 50 mol% or less with respect to the total amount of the structural units derived from the monofunctional component.

Next, the bifunctional (meth)acrylic acid ester (b) generates a pendant vinyl group while branching or crosslinking the copolymer, imparting curability to the copolymer, and thus plays an important role as a crosslinking component to express heat resistance during curing. Do it.

As the bifunctional (meth)acrylic acid ester (b), a compound represented by General Formula (2) is used. In the formula, R ₂ is a hydrocarbon group having 2 to 30 carbon atoms, preferably 9 to 30 carbon atoms, and a structure in which heteroatoms or groups such as an oxygen atom, a nitrogen-containing group, and a sulfur atom may be present in a part of the hydrocarbon group. to be. The heteroatom or group or, with respect to the is substituted in them, is the same, and with the R _1, except that the carbon number of 2 to 30 divalent group of R _2.

As a bifunctional (meth)acrylic acid ester (b) represented by the general formula (2), for example, cyclohexanedimethanol diacrylate, dimethylol tricyclodecane diacrylate, cyclohexane dimethanol dimethacrylate, dimethylol Tricyclodecane dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, 1,4-butanediol diacrylate, hexanediol diacrylate, diethylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol Difunctional (meth)acrylic acid esters such as diacrylate, 1,4-butanediol dimethacrylate, hexanediol dimethacrylate, and diethylene glycol dimethacrylate may be used, but are not limited thereto. In particular, from the viewpoint of reactivity, solubility and heat resistance, a (meth)acrylic acid ester which is a linear fatty chain having 9 to 30 carbon atoms or an ethylene glycol chain is preferable. Specifically, 1,9-nonanedioldi(meth)acrylate, 2-methyl-1,8-octanedioldi(meth)acrylate, triethyleneglycoldi(meth)acrylate, tetraethyleneglycoldi(meth)acrylate )Acrylate, tetradecaneethylene glycol di(meth)acrylate, and 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate are mentioned as a preferable thing. In addition, by using a bifunctional (meth)acrylic acid ester having a ring structure in addition to the chain acrylic acid ester, heat resistance, elastic modulus, solubility, refractive index, and the like can be adjusted according to the application. As a bifunctional (meth)acrylic acid ester having a ring structure, specifically, dimethyloltricyclodecanedi(meth)acrylate, bisphenol A·EO added di(meth)acrylate, bisphenol A·PO added (meth)di Acrylate, etc. are mentioned.

The structural unit derived from the bifunctional (meth)acrylic acid ester (b) may include the structural unit (b1) and other structural units, but all difunctional (meth)acrylic acid esters (b) derived from these The molar fraction Mb calculated by the formula (5) of the structural unit (b) is preferably 0.01 to 0.5, preferably 0.15 to 0.45.

The copolymer has a structural unit (b1) containing a reactive (meth)acrylate group derived from a bifunctional (meth)acrylic acid ester (b) in the side chain, but the molar fraction Mb1 of the structural unit (b1) represented by formula (3) It is good that it is 0.02 to 0.5, Preferably it is 0.1 to 0.3.

By satisfying the molar fraction, it is possible to obtain a molded article having rich curability in light or heat and excellent in heat resistance and mechanical properties after curing.

Further, from another viewpoint, the copolymer is 5 to 70 mol% of the structural unit derived from the component (a), 5 to 50 mol% of the structural unit derived from the component (b), preferably 7 to 45 mol%, more preferably 10 It is good to contain ~ 40 mol%, and (c) 0.5 ~ 30 mol% of the structural unit derived from the component, preferably 1 ~ 25 mol%, particularly preferably 3 ~ 15 mol%. If the structural unit derived from the component (a) does not satisfy 5 mol%, adhesion under moisture resistance is insufficient, which is not preferable. If the structural unit derived from the bifunctional (meth)acrylic acid ester (b) does not meet 5 mol%, it is not preferable because the heat resistance of the cured product is insufficient, and if this structural unit exceeds 50 mol%, the elastic modulus increases and Together, the molding processability is deteriorated and the strength of the molded product is remarkably lowered, which is not preferable. In addition, the structural unit derived from the other monofunctional component (d) is preferably within the range of 60 mol% or less with respect to the total amount of the structural unit derived from the monofunctional component.

Although it does not specifically limit as a manufacturing method of a copolymer, DMP, a monofunctional acrylic acid ester compound, and a bifunctional (meth)acrylic acid ester are adjusted to a desired content, and if necessary, a radical polymerization initiator and a solvent are used at 20 to 200°C. It is produced by polymerization at a temperature of, and is recovered by a commonly used method such as, for example, a steam stripping method or precipitation in a poor solvent.

The weight average molecular weight Mw of this copolymer is 10,000-1,000,000. When it is less than 10,000, the yield of the polymer decreases, and when it is more than 1,000,000, the reactivity decreases. In addition, from the viewpoint of high reactivity, high solubility, low viscosity, and shrinkage stress, Mw is 20,000 to 500,000 as a preferable range.

This copolymer is soluble in dissolving 1 g or more with respect to 100 g of the above-described solvent. Preferably, at 25°C, 5 g or more is dissolved in 100 g of the above-described solvent.

The curable resin composition of the present invention contains the polyfunctional (meth)acrylic acid ester copolymer (A), a monomer (B) having at least one functional group having an unsaturated double bond, and an initiator (C).

The monomer (B) having at least one functional group having an unsaturated double bond may include an oligomer, but it is not the same as the polyfunctional (meth)acrylic acid ester copolymer (A), and in the same case, a polyfunctional (meth) It is calculated as an acrylic acid ester copolymer (A). And the oligomer may be a homopolymer or a copolymer, and the molecular weight (Mw) is preferably a low molecular weight polymer of 10,000 or less, preferably 6000 or less, more preferably 5000 or less, and even more preferably 1000 or less. . Further, the monomer (B) may be a compound having no molecular weight distribution, and in this case, a plurality of compounds can be used. Preferably, it is a monomer having a molecular weight of 1000 or less. When the monomer is an oligomer, the molecular weight means Mw. Further, in the relationship with the soluble polyfunctional (meth)acrylic acid ester copolymer, the molecular weight Mw of the monomer is preferably lower than that, and preferably 1000 or more in the relationship with the Mw of the copolymer (A).

The monomer (B) has at least one functional group having a polymerizable unsaturated double bond, and examples of the functional group having a polymerizable unsaturated double bond include a vinyl group and a (meth)acryloyl group.

The monomer having at least one functional group having an unsaturated double bond is preferably a (meth)acrylate monomer. The (meth)acrylate monomer has one or more (meth)acryloyl groups in the molecule, and one or two or more of them are used. By using these (meth)acrylates in combination with a copolymer, it becomes possible to adjust the viscosity of the composition without lowering the curability, and synergistically, in addition to the heat resistance, optical properties such as low color dispersion and high light transmittance are simultaneously improved. In addition, it becomes possible to improve physical properties such as hardness and flexibility of the cured product.

The (meth)acrylate monomer is preferably a monomer having a molecular weight of 6000 or less, preferably 5000 or less, and particularly 1000 or less. Further, it may be a monomer (oligomer) having the same molecular weight distribution as polyethylene glycol di(meth)acrylate, and in this case, Mw is 6000 or less, preferably 5000 or less, more preferably 2000 or less, and particularly 1000 or less. Advantageously, it is a monomer consisting of a compound having no molecular weight distribution or a mixture thereof.

As the (meth)acrylate monomer, it is preferable to copolymerize with the copolymer (A), for example, a (meth)acrylic acid ester having an alicyclic structure, and a monofunctional, bifunctional or trifunctional (meth) Acrylic acid ester is more preferable, and monofunctional (meth)acrylic acid ester is further preferable. In addition, this (meth)acrylate monomer is preferably a C4-20 aliphatic acrylate, and preferably has 1-3 unsaturated bonds derived from acrylate. Since the aliphatic (meth)acrylic acid ester is excellent in compatibility with the copolymer, it is effective to improve the low water absorption, low elasticity, optical properties and processability as a whole composition with the copolymer. In addition, urethane-modified (meth)acrylates and ethylene oxide-modified (meth)acrylates are effective in improving the flexibility of the cured product. In addition, in order to improve the hardness of the cured product, a trifunctional or higher (meth)acrylate monomer is effective.

Examples of (meth)acrylate monomers include acryloylmorpholine, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. , Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, cyclohexane-1,4-dimethanol mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl ( Meth)acrylate, phenylpolyethoxy (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, o-phenylphenol monoethoxy (meth)acrylate, o-phenylphenolpolye Toxic(meth)acrylate, p-cumylphenoxyethyl(meth)acrylate, isobornyl(meth)acrylate, tribromophenyloxyethyl(meth)acrylate, dicyclopentanyl(meth)acrylate, dish Clopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,4-butanedioldi (meth)acrylate, 1,6-hexanedioldi (meth)acrylate, 1,9- Nonandioldi (meth)acrylate, tricyclodecanedimethanol (meth)acrylate, bisphenol A polyethoxydi (meth)acrylate (e.g., Sartomer, SR-349, SR-348, etc.), Bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, tris(2-hydride) Roxyethyl) isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyethylene glycol di(meth)acrylate (e.g., Satomer, SR -344, SR-268, etc.), tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tri Pentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalate neophen glycol di(meth)acrylate, di(meth), an ε-caprolactone adduct of hydroxypivalate neophen glycol ) Acrylate (e.g. For example, manufactured by Nihon Kayaku Co., Ltd., KAYARAD HX-220, HX-620, etc.), trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, ditrimethylolpropane tetra( And monomers such as meth)acrylate and urethane-modified (meth)acrylate (for example, Daicel-Cytech Co., Ltd. product, EBACRYL 8405, EBACRYL8402, etc.). Particularly preferably, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, pentaerythritol tri(meth)acrylate, di Pentaerythritol hexa (meth) acrylate, urethane modified (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, and ethylene glycol di (meth) acrylate.

The curable resin composition of the present invention contains a polymerization initiator, preferably a photopolymerization initiator. The curable resin composition of the present invention can be molded and cured even if it is thermally polymerized, but in the case of molding and curing an optical material such as a lens, photocuring capable of strictly controlling shape is advantageous, and therefore it is advantageous to add a photopolymerization initiator.

Examples of the photoinitiator include benzoin, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; Acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropane-1 Acetophenones such as -one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; Anthraquinones such as 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; Thioxanthones such as 2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, and 2-chloro thioxanthone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone; And phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

These can be used alone or as a mixture of two or more, and tertiary amines such as triethanolamine and methyldietanolamine, N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, etc. It can be used in combination with accelerators such as benzoic acid derivatives.

The curable resin composition of the present invention contains the copolymer, a monomer having at least one functional group having an unsaturated double bond, and an initiator as essential components, and the content ratio is as follows. The blending amount of the monomer is 90 to 30 parts by weight, preferably 80 to 30 parts by weight, more preferably 60 to 45 parts by weight, based on 100 parts by weight of the total amount of the copolymer and the monomer. In addition, the blending amount of the initiator is 0.1 to 10 parts by weight, preferably 1.0 to 5 parts by weight, based on 100 parts by weight of the total amount of the copolymer and the monomer.

When the blending ratio is within the above range, the balance of properties of moldability, heat resistance, and optical properties synergistically shown by releasability and curing properties is improved. In addition, if the initiator is too small, shortage of curing is liable to occur, and heat resistance and light resistance are lowered, and if too large, mechanical strength is lowered or heat resistance is lowered. In addition, when an organic solvent and a filler are included in a curable resin composition, the said content is calculated excluding these.

In addition, in the curable resin composition of the present invention, if necessary, a polymerization inhibitor, an antioxidant, a release agent, a photosensitizer, an organic solvent, a silane coupling agent, a leveling agent, an antifoaming agent, an antistatic agent, an ultraviolet absorber, a light stabilizer, an inorganic, organic It is also possible to add various fillers, anti-mold agents, antibacterial agents, and the like to the curable resin composition of the present invention to impart the desired functionality.

The curable resin composition of the present invention can be obtained by mixing the copolymer, the monomer and the initiator, and, if necessary, other components in an arbitrary order. The curable resin composition of the present invention is stable over time.

The curable resin composition of the present invention can obtain a cured product by irradiating an active energy ray such as ultraviolet rays. Here, specific examples of the light source used in the case of curing by irradiation with active energy rays include, for example, a xenon lamp, a carbon arc, a sterilization lamp, a fluorescent lamp for ultraviolet rays, a high pressure mercury lamp for radiation, a medium pressure mercury lamp, a high pressure mercury lamp, and A mercury lamp, an electrodeless lamp, a metal halide lamp, or an electron beam generated by a scanning type or curtain type electron beam accelerator. In addition, when curing the curable resin composition of the present invention by irradiation with ultraviolet rays, the amount of ultraviolet irradiation required for curing is preferably about 300 to 20000 mJ/cm 2. Further, in order to sufficiently cure the resin composition, it is preferable to irradiate an active energy ray such as ultraviolet rays in an inert gas atmosphere such as nitrogen gas.

The cured resin product obtained by molding and curing the curable resin composition of the present invention is excellent as an optical material such as a prism and a lens. It is particularly useful to be used as an adhesive layer, and exhibits an excellent effect on adhesion between optical materials in a moisture resistant environment. In addition, it is useful as a material for an optical plastic lens such as a prism lens sheet, a Fresnel lens, and a lenticular lens.

When bonding a polarizing film and a protective plate by using the curable resin composition of the present invention, for example, it is not limited to a protective plate such as an alkali-free glass product or quartz glass product having excellent active energy ray transmission, and an acrylic plate having a large ultraviolet absorption, Even if it is a protective plate such as polycarbonate, the composition can be used because of its favorable reaction curability.

The curable resin composition of the present invention is applied to a substrate such as a polarizing film using a coating device such as a roll coater, a spin coater, or a screen printing method to have an adhesive film thickness of 1 to 100 µm to bond the protective plate to the protective plate. It can be bonded by irradiation from above and curing.

Example

Next, the present invention will be described by examples, but the present invention is not limited thereto. In addition, all of the parts in each example are parts by weight. In addition, for the measurement of softening temperature and the like in Examples, sample preparation and measurement were performed by the method shown below.

1) Molecular weight and molecular weight distribution of polymer

Measurement of the molecular weight and molecular weight distribution of the polyfunctional (meth)acrylic acid ester copolymer was performed using GPC (HLC-8120GPC, manufactured by Tosoh), solvent: tetrahydrofuran (THF), flow rate: 1.0 ml/min, column temperature: 40° C. Conducted in. The molecular weight of the copolymer was measured as a molecular weight in terms of polystyrene using a calibration curve based on monodisperse polystyrene.

2) Structure of polymer

It was determined by ¹³ C-NMR and ¹ H-NMR analysis using a JNM-LA600 type nuclear magnetic resonance spectroscopy device manufactured by Nihon Denshi. Chloroform-d1 was used as a solvent, and the resonance line of tetramethylsilane was used as an internal standard.

3) Measurement of solvent solubility and gel formation

To measure the solubility of the polyfunctional vinyl aromatic copolymer, 2 g of a sample was dissolved in 10 g of various solvents (toluene, xylene, propylene glycol monomethyl ether acetate, tetrahydrofuran, dichloroethane or chloroform), and the transparency of the sample after dissolution was observed. Solubility was evaluated by classifying it as ○: transparent, △: translucent, x: opaque or not dissolved. At the same time, the gel formation was also visually confirmed, and the presence or absence of the gel was evaluated.

4) Sample preparation and measurement of elastic modulus measurement

Polyfunctional (meth)acrylic acid ester copolymer is dissolved in PGMEA, perbutyl O (made by Nihon Yu) is added as a thermal polymerization initiator, and a varnish made of a curable resin composition is applied on a glass substrate, and nitrogen streams After drying at 100° C. for 10 minutes, it was cured at 200° C./1 h under a nitrogen stream to prepare a sample for measurement of a 200 μm film. This was set in a DMA (dynamic viscoelasticity analyzer) measuring device, and measured by scanning from 20°C to 150°C at a temperature increase rate of 10°C/min under a nitrogen stream to measure E'at 30°C. By reading the value, the elastic modulus of the sample was determined.

5) Measurement of thermal weight reduction and heat discoloration resistance

To measure the thermal decomposition temperature and heat discoloration resistance of the polyfunctional (meth)acrylic acid ester copolymer, a sample is set in a TGA (thermobalance) measuring device, and a temperature rise rate of 10°C/min under a nitrogen stream is 30°C to 320°C. The measurement was carried out by scanning up to, and the amount of weight loss at 300°C was obtained, and the amount of discoloration of the sample after measurement was visually confirmed, and ◎: no thermal discoloration, ○: pale yellow, △: brown, ×: classified as black By doing this, heat discoloration resistance was evaluated.

6) Measurement of refractive index

The polyfunctional (meth)acrylic acid ester copolymer was dissolved in toluene, and perbutyl O as an initiator was added thereto at 1.0 part by weight based on 100 parts by weight of the soluble polyfunctional (meth)acrylic acid ester copolymer. A cast sheet was prepared from this polymer solution, and the cast sheet was crushed to pellet, filled into a press mold, and cured at 170°C for 1 hour with a press molding machine. Using the obtained cured parallel plate as a test piece, the refractive index of the d-line (587.6 nm) was measured with KPR-200 (manufactured by Shimadzu Calnew). The measurement timing was immediately after molding (initial) and after being put into a high-temperature, high-humidity machine under a humid heat condition of 85°C x 85 RH for one week (after wet heat).

7) Hygroscopic adhesion test

The varnish obtained by diluting the copolymer with PGMEA was applied onto a glass substrate, dried at 100° C. for 10 minutes, and then cured at 200° C. for 1 hour in a nitrogen stream in an inert oven. Next, the glass substrate on which the cured coating film of the copolymer was put was put on the surface of the coating film in accordance with JISK5400 by placing 11 vertical and horizontal incisions at 1 mm intervals to make 100 checkerboard scales. After the cellophane tape was brought into close contact with its surface, the number of mass scales that remained without peeling when removed at one time was counted (initial). In addition, after immersing the coated glass substrate in a hot water at 85°C for a predetermined period of time, the water on the surface was wiped off, and the cellophane tape was adhered to the surface again, and after peeling off at a time, the number of mass scales remaining without peeling was counted (after immersion). ).

The symbol of the raw material used is shown below.

DMTCD: dimethyloltricyclodecane diacrylate

NDDA: 1,9-nonanediol diacrylate

BDDA: 1,4-butanediol diacrylate

HOP: 2-hydroxypropyl acrylate

HO: 2-hydroxyethyl methacrylate

EHDGA: 2-ethylhexyl EO (n≒2) modified acrylate

LA: lauryl acrylate

LM: lauryl methacrylate

nBA: n-butylacrylate

DCPA: dicyclopentanylacrylate

αMSD: 2,4-diphenyl-4-methyl-1-pentene

DDME: n-dodecylmercaptan

Example 1

NDDA 252.35g, DCPA 309.42g, EHDGA 544.76g, HOP 65.07g, αMSD 222.32g, and toluene 700ml were put into a 3.0L reactor, and 65.60 mmol of benzoyl peroxide was added at 85°C and reacted for 2 hours. After the polymerization reaction was stopped by cooling, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, separated, dried, and weighed to obtain a copolymer A431.1 g (yield: 31 wt%).

Mw of the obtained copolymer A was 117,234, Mn was 20,874, and Mw/Mn was 5.6. By performing ¹³ C-NMR, ¹ H-NMR analysis and elemental analysis, Copolymer A contains 11.8 mol% of structural units derived from NDDA, 30.1 mol% of structural units derived from DCPA, and 49.7 structural units derived from EHDGA. It contained 9.4 mol% of structural units derived from mol% and HOP. Moreover, 2.7 mol% of terminal groups of the structure derived from αMSD were present. In addition, the molar fraction of structural units derived from acrylates is calculated using the structural units derived from all acrylates as 100, and the molar fraction of αMSD, etc. is calculated using the structural units derived from all acrylates + αMSD as 100. Value. Mb1 is the molar fraction of pendant acrylate, and it is calculated using 100 as the structural unit derived from all acrylates.

Copolymer A is soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and formation of a gel was not recognized. In addition, the cast film of Copolymer A was a transparent film without fogging.

Examples 2 and 3 and Comparative Examples 1 and 2

Using various bifunctional acrylates and monofunctional (meth)acrylates, polymerization was carried out in the same manner as in Example 1 with the raw material composition shown in Table 1.

Table 1 shows the amount of raw material used for the reaction, and Table 2 shows the test results of the copolymer and its cured product. Unless otherwise noted, other reaction conditions and measurement conditions are the same as in Example 1. In Table 1, the amount of raw material used is expressed in moles and weights (g), but the format of the substrate was made in moles/g.

Claims (7)

The following general formula (1)

(In the formula, R ₁ is a linear or branched hydrocarbon group having 9 to 30 carbon atoms, and an oxygen atom, a sulfur atom, or a nitrogen-containing group may be contained in the hydrocarbon group. R is H or a methyl group.)
Monofunctional (meth)acrylic acid ester (a) represented by,
The following general formula (2)

(In the formula, R ₂ is a hydrocarbon group having 2 or more and 30 or less carbon atoms, and an oxygen atom, a sulfur atom, or a nitrogen-containing group may be contained in the hydrocarbon group. R is H or a methyl group.)
Bifunctional (meth)acrylic acid ester (b) represented by,
It is a copolymer obtained by copolymerizing monomers containing 2,4-diphenyl-4-methyl-1-pentene (c),
Having a reactive (meth)acrylate group derived from a bifunctional (meth)acrylic acid ester (b) in the side chain, and 2,4-diphenyl-4-methyl-1-pentene (c) at the terminal As a copolymer having a derived structural unit, the weight average molecular weight is 10,000 to 1,000,000, and the molar fraction Mb, which is the unit derived from the component (b) in all acrylic acid ester units, is derived from the monofunctional (meth)acrylic acid ester (a). When the introduced amount (mol) of the unit and the unit derived from the bifunctional (meth)acrylic acid ester (b) is a and b, respectively, it is 0.01 to 0.5 as b/(a+b),
The component (a) of all monofunctional (meth)acrylic acid esters is 40 mol% or more,
Further, a polyfunctional (meth)acrylic acid ester copolymer soluble in toluene, xylene, propylene glycol monomethyl ether acetate, tetrahydrofuran, dichloroethane or chloroform. The method of claim 1,
In the general formula (1), R ₁ is a linear or branched fatty chain having 9 to 30 carbon atoms, or an ethylene glycol chain, wherein the polyfunctional (meth)acrylic acid ester copolymer. The method of claim 1,
In the general formula (2), R ₂ is a linear fatty chain having 2 or more and 30 or less carbon atoms, or an ethylene glycol chain, wherein the polyfunctional (meth)acrylic acid ester copolymer. The method of claim 1,
When the introduced amount (mol) of the reactive (meth)acrylate group-containing unit derived from the bifunctional (meth)acrylic acid ester (b) is set to b1, the molar fraction Mb1 of the unit is set to b1/(a+b) and 0.02 to 0.5 Polyfunctional (meth) acrylic acid ester copolymer, characterized in that. The method of claim 1,
When the introduced amount (mol) of the unit derived from 2,4-diphenyl-4-methyl-1-pentene (c) is c, the molar fraction Mc of the unit is c/(a+b+c), and 0.005 to Polyfunctional (meth) acrylic acid ester copolymer, characterized in that 0.3. A curable resin composition comprising the polyfunctional (meth)acrylic acid ester copolymer according to any one of claims 1 to 5, a monomer having at least one functional group having an unsaturated double bond, and an initiator. An optical article obtained by curing and molding the curable resin composition according to claim 6.