JP4970107B2 - Soluble polyfunctional vinyl aromatic copolymer and method for producing the same - Google Patents

Description

  The present invention relates to a soluble polyfunctional vinyl aromatic polymer having improved heat resistance, transparency, compatibility and processability, and a method for producing the same.

  Many of the monomers having a reactive active unsaturated bond can generate a multimer by selecting an appropriate reaction condition and a catalyst that causes a chain reaction by cleavage of the unsaturated bond. In general, the types of monomers having an unsaturated bond are extremely diverse, so the variety of types of resins obtained is also remarkable. However, there are relatively few types of monomers that can obtain a high molecular weight compound having a molecular weight of 10,000 or more, generally called a high molecular compound. For example, ethylene, substituted ethylene, propylene, substituted propylene, styrene, alkyl styrene, alkoxy styrene, norbornene, various acrylic esters, butadiene, cyclopentadiene, dicyclopentadiene, isoprene, maleic anhydride, maleimide, fumaric acid ester, allyl compound And the like as typical monomers. A wide variety of resins have been synthesized by using these monomers alone or copolymerizing them.

  Applications of these resins are mainly limited to the field of relatively inexpensive consumer equipment, and advanced technology fields that require high heat resistance, dimensional stability, and fine workability in the field of optical and electronic materials. There is almost no application to. The reason for this is that polymers synthesized from the above-mentioned monomers are thermoplastic, and it is necessary to use a considerably high molecular weight to satisfy the mechanical properties. The characteristic required in the technical field is sacrificed.

  As a method for solving the disadvantages of such vinyl-based thermoplastic polymers, a very small amount of an aromatic polyfunctional vinyl compound such as an aromatic divinyl compound or an aromatic trivinyl compound is added to the above-mentioned vinyl monomer. Improvements in resin properties such as these have been made. For example, in JP-A-2-170806 (Patent Document 1), an aromatic polyfunctional vinyl compound and a styrene monomer are copolymerized with heat or an initiator to obtain a styrene polymer having a wide molecular weight distribution. And that this polymer exhibits high impact strength. However, if the polymerization conversion rate is increased according to the technique disclosed herein, the cross-linking reaction with the aromatic polyfunctional vinyl compound occurs rapidly. Therefore, when there is a large amount of aromatic polyfunctional vinyl compound, the gelation of the resin occurs. , Workability and appearance are significantly impaired. Therefore, the conventional modification of the resin with the aromatic polyfunctional vinyl compound can suppress the addition amount of the aromatic polyfunctional vinyl compound as low as 50 to 250 ppm. There is a drawback that the reforming effect is not sufficient for application in the advanced technology field.

  Furthermore, JP 2000-128908 A (Patent Document 2) discloses a styrene polymer having a controlled degree of branching using a polyfunctional chain transfer agent in combination with an aromatic polyfunctional vinyl polymer and a method for producing the same. However, the amount of the aromatic polyfunctional vinyl polymer added to the styrene monomer is only 1 to 700 ppm, and the heat resistance and processability are still the same as those of conventional thermoplastic resins. In addition, when a large amount of an aromatic polyfunctional vinyl compound is blended and polymerized according to the techniques disclosed in these documents, the resulting polymer usually has a highly crosslinked structure, and is an insoluble / infusible gel having no workability. In many cases, it became a polymer, and the moldability was still not improved.

  On the other hand, multi-branched polymers consisting of highly branched (branched) polymer chains are less entangled with molecular chains, have a lower viscosity than linear polymers of the same molecular weight, and introduce many reactive groups into the branches. It has been attracting attention as a highly functional material. JP-T-2001-512752 (Patent Document 3) contains a monofunctional vinyl monomer: 50 to 99.9 parts by weight and an aromatic polyfunctional vinyl compound: 0.1 to 50 parts by weight in the presence of a radical polymerization initiator. Below, the manufacturing method of the multibranched polymer which superposes | polymerizes at 250-400 degreeC is disclosed. However, looking at the results disclosed in this example, by performing polymerization at a high temperature exceeding 250 ° C., a gel component generated by the crosslinking reaction is thermally decomposed to reduce the molecular weight, thereby generating a multi-branched polymer. I am letting. Therefore, since the technique disclosed here cannot increase the vinyl group content in the produced polymer, the modification effect on the heat resistance by the aromatic polyfunctional vinyl compound is sufficient for application to the advanced technology field. It's not a good thing. Moreover, since it superposes | polymerizes at very high temperature, there existed a problem that manufacture was difficult in the case of industrial implementation.

  Further, in US Pat. No. 5,767,211 (Patent Document 4), a multi-branched polymer having no crosslinked structure is obtained by polymerizing a bi- or trifunctional vinyl compound in the presence of an azo radical polymerization initiator and a cobalt chain transfer catalyst. A manufacturing method for synthesizing is disclosed. However, in this polymerization method, since a chain transfer catalyst that promotes β-hydrogen elimination is used to generate a branched structure, a structure having a double bond in the vicinity of the branched structure in the generated polymer. Will have. For this reason, even if a thermosetting operation is performed to increase the heat resistance of the produced polymer, the effect of improving the heat resistance is small because the reactivity of the polymer is low, and it is not suitable for application in the advanced technology field. There were drawbacks. Furthermore, in this production method, since the chain transfer reaction relies exclusively on the chain transfer ability of the cobalt chain transfer catalyst, it is necessary to add a large amount of the chain transfer catalyst to the polymerization system, which significantly slows down the polymerization rate. Furthermore, there have been problems in practical use such as difficulty in removing the catalyst when recovering the polymer.

  Non-Patent Document 1 discloses that a solvent-soluble divinylbenzene polymer can be obtained by anionic polymerization of divinylbenzene using di-iso-propylamine and butyllithium as a catalyst. However, when an attempt is made to copolymerize divinylbenzene and other monomers in accordance with this technology, an anionic polymerization catalyst is used, and thus a long block copolymer with a long chain of divinyl compounds such as divinylbenzene is used. Since the polymer is produced, the storage stability is poor, and there is a drawback that a gel or a high molecular weight product is easily produced during storage. Also, the polymerization method is industrially carried out such that the selectivity of the vinyl group at the time of polymerization is not sufficient so that gelation is likely to occur, the monomer concentration cannot be increased, and the polymerization temperature cannot be raised above 0 ° C. It was a problematic way to do. Non-Patent Document 2 discloses that a solvent-soluble divinylbenzene-styrene copolymer can be obtained by anionic polymerization of divinylbenzene and styrene using lithium di-iso-propylamide as a catalyst. However, the heat resistance is not sufficient, and there is a disadvantage that the characteristics are not sufficient as a material used in the advanced technology field. In addition, this polymerization method is also susceptible to gelation because the selectivity of the vinyl group during polymerization is not sufficient, and it is necessary to perform polymerization at a low monomer concentration and at a polymerization temperature as low as 0 ° C. or less. It was a problematic way to do.

  Non-Patent Document 3 and Non-Patent Document 4 disclose that a solvent-soluble divinylbenzene polymer can be obtained by cationic polymerization of divinylbenzene using acetyl perchlorate as a catalyst. However, since this divinylbenzene polymer does not contain (meth) acrylate in its main chain skeleton and is a polymer composed of an internal olefin structure, it has low heat resistance and is a material used in advanced technology fields. As such, there was a drawback that the characteristics were not sufficient.

  As a method for solving the problems of the above existing technology, JP 2004-123873 A (Patent Document 5) discloses divinyl aromatic compound (a) and monovinyl aromatic compound (b) in an organic solvent, Lewis acid catalyst. And a soluble polyfunctional vinyl aromatic copolymer obtained by polymerizing at a temperature of 20 to 100 ° C. in the presence of an initiator having a specific structure. JP 2005-213443 (Patent Document 6) contains 20 to 100 mol% of a divinyl aromatic compound (a) in the presence of a quaternary ammonium salt by using a Lewis acid catalyst and an initiator having a specific structure. A method for producing a soluble polyfunctional vinyl aromatic copolymer having a controlled molecular weight distribution by cationic polymerization of the monomer component at a temperature of 20 to 120 ° C. is disclosed. Soluble polyfunctional vinyl aromatic copolymers easily obtained by the techniques disclosed in these are excellent in solvent solubility and processability, and by using this, a cured product excellent in heat resistance and heat decomposability can be obtained. Can do. However, although the soluble polyfunctional vinyl aromatic copolymer obtained by these techniques is a polymer having excellent heat resistance in terms of giving a cured product having a high glass transition temperature, optical properties such as transparency can be obtained. Not only are the properties insufficient, but the thermal decomposition at high process temperatures is not sufficient in terms of heat discoloration and outgassing, and there are cases where defects such as discoloration and foaming occur due to a high thermal history of 270 ° C or higher. there were.

JP-A-2-170806 JP 2000-128908 A JP-T-2001-512752 US Patent No. 5,767,211 JP 2004-123873 A Japanese Patent Laid-Open No. 2005-213443 Makromol. Chem., 1978, 179, 2069-2073 Makromol.Chem., 1988, 189, 723-731 Macromolecules, 1980, Volume 13, pages 1350-1354 Macromolecules, 1982, Volume 15, pp. 1221-1225

  A skeleton derived from a bifunctional (meth) acrylic acid ester that solves the various problems of the above prior art, has excellent thermal decomposition resistance against heat history at high temperatures, and has excellent optical properties and compatibility. Thus, a polyfunctional vinyl aromatic polymer having a controlled molecular weight distribution excellent in processability and solvent solubility has been desired.

  The present invention is a novel multifunctional vinyl having high optical properties, having a reactive (meth) acrylate group with excellent photocurability in the side chain, and having a controlled molecular weight distribution and solvent solubility that are excellent in processability. An object of the present invention is to provide an aromatic copolymer and a method for producing the copolymer with high efficiency.

The present invention, monovinyl aromatic compound and a difunctional (meth) obtained by copolymerizing acrylic acid ester, structural units derived from monovinyl aromatic compound (a) and 2 (meth) structural units derived from an acrylic acid ester A copolymer having (b), wherein the molar fraction of the structural unit (b1) containing a reactive (meth) acrylate group derived from a bifunctional (meth) acrylate ester in the side chain is represented by the following formula:
(B1) / [(a) + (b)] ≧ 0.10
(Wherein (a), (b) and (b1) represent the number of moles of the structural unit (a), the structural unit (b) and the structural unit (b1), respectively), and further monovinyl aromatic 10 to 80 mol% of structural unit (a) derived from a compound 90 to 20 mol% of structural unit (b) derived from a bifunctional (meth) acrylic acid ester, and the total of structural units (a) and (b) Is 70 mol% or more, the number average molecular weight Mn of the copolymer is 500 to 1,000,000, and the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is 100. It is a soluble polyfunctional vinyl aromatic copolymer that is not more than 0.0 and is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform.

Further, the present invention provides (A) one or more chain transfer agents selected from the group consisting of 2,4-diphenyl-4-methyl-1-pentene, thiol compounds and thioether compounds with respect to 100 parts by weight of the total monomers. 10 to 200 parts by weight , 10 to 80 mol% of monovinyl aromatic compound and 90 to 20 mol% of bifunctional (meth) acrylic acid ester , monovinyl aromatic compound and bifunctional (meta) in all monomers ) a monomer component Ru der total more than 70 mol% of acrylic acid ester, a method for producing a soluble polyfunctional vinyl aromatic copolymer characterized by polymerizing at a temperature of 50 to 200 ° C..

  Here, the monovinyl aromatic compound is preferably at least one monovinyl aromatic compound selected from the group consisting of styrene and ethylvinylbenzene. Bifunctional (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, diethylene glycol di ( One or more bifunctional (meth) acrylic acid esters selected from the group consisting of (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate are preferably mentioned.

  Hereinafter, the soluble polyfunctional vinyl aromatic copolymer of the present invention and the production method thereof will be described in detail.

  The soluble polyfunctional vinyl aromatic copolymer of the present invention is a copolymer obtained by copolymerizing a monovinyl aromatic compound and a bifunctional (meth) acrylic acid ester, and is a structural unit derived from a monovinyl aromatic compound ( a) a structural unit having a structural unit (b) derived from a bifunctional (meth) acrylic acid ester and containing a reactive (meth) acrylate group derived from a bifunctional (meth) acrylic acid ester in the side chain ( b1) and its abundance (molar fraction) satisfies the formula (1). The soluble polyfunctional vinyl aromatic polymer has a number average molecular weight Mn of 500 to 1,000,000, a molecular weight distribution (Mw / Mn) of 100.0 or less, and is soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform. It is a soluble polyfunctional vinyl aromatic copolymer.

  The soluble polyfunctional vinyl aromatic copolymer of the present invention contains 2 to 90 mol%, preferably 5 to 85 mol%, more preferably 10 to 80 mol% of the structural unit (a) derived from the monovinylaromatic compound. . It contains 98 to 10 mol%, preferably 95 to 15 mol%, more preferably 90 to 20 mol% of the structural unit (b) derived from the bifunctional (meth) acrylic acid ester. When the structural unit (b) is less than 10 mol%, the heat resistance of the cured product is insufficient, and when it exceeds 98 mol%, the moldability is lowered.

  In order to improve the solvent solubility and processability of the soluble polyfunctional vinyl aromatic copolymer of the present invention, it is necessary to use a monovinyl aromatic compound as a raw material monomer and to have a structural unit (a) derived therefrom. .

  Examples of monovinyl aromatic compounds include styrene, nuclear alkyl-substituted monovinyl aromatic compounds such as methylstyrene and ethylstyrene, α-alkyl-substituted monovinyl aromatic compounds such as α-methylstyrene, β-alkyl-substituted styrene, alkoxy-substituted styrene, and indene. Examples thereof include, but are not limited to, derivatives and acenaphthylene derivatives. These can be used alone or in combination of two or more. By introducing the structural unit (a) derived from these components into the polyfunctional vinyl aromatic polymer, not only can the gelation of the polymer be prevented and the solubility in a solvent can be increased, but also The processability at the time of application of the functional vinyl aromatic polymer can be improved. Preferred examples include styrene, ethyl vinyl benzene (both m- and p-isomers) and ethyl vinyl biphenyl (each isomer) in terms of cost, prevention of gelation and moldability of the resulting copolymer. And the like.

  Bifunctional (meth) acrylic acid esters give structural units (b), but there are several types of structural units (b). It is preferable that at least a part, preferably a large part, is the structural unit (b1). In addition, there are a branched structural unit necessary for making a polyfunctional vinyl aromatic copolymer and a structural unit that gives a double bond in the main chain. However, since the structural unit which gives a crosslinked structure inhibits the solubility, it is adjusted to a range giving the solubility. The structural unit (b1) plays a major role as a crosslinking component when the soluble polyfunctional vinyl aromatic copolymer exhibits heat resistance by photocuring or thermosetting.

The structural unit (b1) is represented by the following formula (b1). In the formula, R is hydrogen or a methyl group, and Y is a residue formed by removing OH from a divalent alcohol.

  Bifunctional (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, diethylene glycol di ( Di (meth) of ε-caprolactone adducts of (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and hydroxybivalic acid neopenglycol Bifunctional (meth) acrylic acid esters such as acrylates (for example, KAYARAD HX-220, HX-620, etc., manufactured by Nippon Kayaku Co., Ltd.) can be used, but are not limited thereto. These can be used alone or in combination of two or more.

  Here, suitable specific examples of the bifunctional (meth) acrylic acid ester include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1, in terms of cost and heat resistance of the obtained polymer. One or more bifunctional (meth) acryls selected from the group consisting of 4-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate There are acid esters. More preferred are ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, and diethylene glycol di (meth) acrylate. In particular, from the viewpoint of cost and availability, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and diethylene glycol di (meth) acrylate are most preferably used.

  In order to improve the solvent solubility and processability of the soluble polyfunctional vinyl aromatic copolymer of the present invention, other monomers other than the monovinyl aromatic compound and the bifunctional (meth) acrylic ester are used as reaction raw materials (monomer components). ) Can also be used.

  As such another monomer, mono (meth) acrylic acid ester is preferable. Examples of mono (meth) acrylic acid esters include methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-methylhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, and the like. Is preferably methyl methacrylate or n-butyl acrylate. These (meth) acrylic acid ester monomers may be used alone or in combination of two or more, but from the group consisting of methyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate and n-butyl acrylate. Most preferably, the selected one or more (meth) acrylic acid esters.

  Further, the structural unit (c) derived from these other monomers is preferably contained within a range of less than 30 mol% with respect to the total amount of the structural units. Therefore, the amount used as a monomer is preferably less than 30 mol% with respect to the total amount of monomers.

  The polyfunctional vinyl aromatic copolymer of the present invention has a molar fraction of the structural unit (b1) containing a reactive (meth) acrylate group derived from a bifunctional (meth) acrylic ester in the side chain represented by the formula (1). It is necessary to be 0.05 or more in the calculation by. The molar fraction is preferably 0.1 or more, particularly preferably 0.15 or more. When the molar fraction is 0.05 or more, a molded product having excellent photocurability and excellent heat resistance and mechanical properties after curing can be obtained. In the formula (1), (a) is the number of moles of the structural unit (a) and (b) the number of moles of the structural unit (b), and (b1) is the number of moles of the structural unit (b1). If the units are the same, the number of moles may be a mole fraction or mole%.

  Furthermore, the number average molecular weight Mn (based on standard polystyrene conversion obtained using gel permeation chromatography) of the polyfunctional vinyl aromatic copolymer of the present invention is 500 to 1,000,000, preferably 700 to 300,000. Most preferably, it is 1000-10000. If the Mn is less than 500, the viscosity of the soluble polyfunctional vinyl aromatic polymer is too low, so that the workability is lowered or the heat resistance of the cured product is lowered. Further, if Mn is 1000000 or more, gel is likely to be generated, and when formed into a molded body or film, the appearance and optical characteristics are deteriorated, which is not preferable.

  Further, the polyfunctional vinyl aromatic polymer of the present invention has a molecular weight distribution (Mw / Mn) value of 100 or less, preferably 50.0 or less. Preferably, it is 40.0 or less. Especially preferably, it is 20.0 or less. Most preferably 10.0. Note that the value of Mw / Mn is 1.5 or more, preferably 2 or more. If Mw / Mn exceeds 50.0, problems such as deterioration in processing characteristics of soluble polyfunctional vinyl aromatic polymer and generation of gel are not preferred.

  In the method for producing a soluble polyfunctional aromatic vinyl copolymer of the present invention, one or more chain transfer agents selected from the group consisting of 2,4-diphenyl-4-methyl-1-pentene, thiol compounds and thioether compounds (A ) In the presence of 2 to 90 mol% of the monovinyl aromatic compound and 98 to 10 mol% of the bifunctional (meth) acrylic acid ester (b) at a temperature of 50 to 200 ° C. To polymerize.

  As the chain transfer agent (A), one or more chain transfer agents selected from the group consisting of 2,4-diphenyl-4-methyl-1-pentene, thiol compounds and thioether compounds are used. 2,4-diphenyl-4-methyl-1-pentene is sometimes referred to as α-methylstyrene dimer.

  Suitable thiol compounds include n-dodecyl mercaptan and t-dodecyl mercaptan. On the other hand, suitable thioether compounds include benzyl phenyl sulfide, butyl ethyl sulfide, t-butyl methyl sulfide and dibutyl disulfide. Among these, α-methylstyrene dimer is preferably used because it is easy to control the molecular weight distribution.

  The amount of the chain transfer agent used is not particularly limited, but is usually 1 to 300 parts by weight with respect to 100 parts by weight of the total amount of monomer components from the viewpoint of controlling the molecular weight distribution. Is preferable, and it is further desirable to be in the range of 5 to 250 parts by weight. Most preferably, it is in the range of 10 to 200 parts by weight.

  In the production method of the present invention, a polymerization initiator can be made unnecessary by performing radical thermal polymerization using a thermal initiation reaction of a divinyl aromatic compound and a monovinyl aromatic compound. On the other hand, when the initiation reaction rate by the thermal initiation reaction is low, a radical polymerization initiator can be added.

  In this case, examples of the radical polymerization initiator used include ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (tert-butylperoxy) ) Peroxyketals such as -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate; cumene Hydroperoxides such as hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl- 2,5-di (tert-butylperoxy) hexane, di Dialkyl peroxides such as sopropylbenzene peroxide and tert-butylcumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; bis (tert -Peroxycarbonates such as butylcyclohexyl) peroxydicarbonate; organic peroxidation such as peroxyesters such as tert-butylperoxybenzoate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane -Based polymerization initiators, 2,2'-azobisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile), azocumene 2,2'-azobismethylvaleronitrile, 4,4'-azobis (4-cyanovaleric acid) An azo polymerization initiator such as

  The amount of the radical polymerization initiator used is not particularly limited, but is usually preferably 0.01 to 25 parts by weight based on 100 parts by weight of the total amount of monomer components. More desirably, it is in the range of ˜20 parts by weight. Most preferably, it is in the range of 0.1 to 10 parts by weight.

  The polymerization reaction can basically be carried out by bulk polymerization without using a solvent, but can also be carried out in one or more organic solvents that dissolve the soluble polyfunctional vinyl aromatic copolymer to be produced. The organic solvent is a compound that does not essentially inhibit radical polymerization and can dissolve a chain transfer agent, an initiator, a monomer, and a polyfunctional vinyl aromatic copolymer to form a uniform solution. It can be used without any particular restrictions.

  Organic solvents include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, propylbenzene, butylbenzene; linear aliphatic carbonization such as ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, etc. Hydrogens; branched aliphatic hydrocarbons such as 2-methylpropane, 2-methylbutane, 2,3,3-trimethylpentane, and 2,2,5-trimethylhexane; cyclics such as cyclohexane, methylcyclohexane, and ethylcyclohexane Aliphatic hydrocarbons; paraffin oil obtained by hydrorefining petroleum fractions and the like. Among these, toluene, xylene, pentane, hexane, heptane, octane, 2-methylpropane, 2-methylbutane, cyclohexane, methylcyclohexane and ethylcyclohexane are preferable. Toluene, xylene, methylcyclohexane and ethylcyclohexane are more preferable from the viewpoints of the balance between polymerizability and solubility and easy availability.

  These organic solvents are used alone or in combination of two or more. Although there is no restriction | limiting in particular in the usage-amount of a solvent, it is not desirable to use it excessively from a point of productivity.

  In the production method of the present invention, the polymerization is carried out in a temperature range of 50 to 200 ° C. If the polymerization reaction is carried out at a temperature lower than 50 ° C., the polymerization rate is lowered, which is not preferable from the viewpoint of industrial implementation. If the temperature exceeds 200 ° C., the selectivity of the reaction is lowered, so that the reaction is difficult to control, and due to crosslinking. This is not preferable because an insoluble gel is easily generated.

  The method for recovering the copolymer after the termination of the polymerization reaction is not particularly limited. For example, a commonly used method such as a steam stripping method or precipitation with a poor solvent may be used.

  When the soluble polyfunctional vinyl aromatic copolymer of the present invention is thermally cured, a cured product having excellent heat resistance and the like can be obtained. Moreover, when a soluble polyfunctional vinyl aromatic copolymer is put into a mold and heated to be molded and cured, or previously molded into a sheet shape and thermally cured, a cured product or a cured sheet having excellent heat resistance and the like can be obtained. . The soluble polyfunctional vinyl aromatic copolymer of the present invention can be used in the form of a resin composition containing various resin additives or other resins. It can also be used in the form of a paint by dissolving in a solvent.

  The soluble polyfunctional vinyl aromatic copolymer of the present invention or the soluble polyfunctional vinyl aromatic copolymer obtained by the production method of the present invention can be processed into a molding material, sheet or film, and has a high refractive index, low Optical materials or semiconductor-related materials that can satisfy characteristics such as dielectric constant, low water absorption, and high heat resistance, as well as paints, photosensitive materials, adhesives, sewage treatment agents, heavy metal scavengers, ion exchange resins, charging It can be applied to an inhibitor, an antioxidant, an antifogging agent, an antirust agent, a dyeproofing agent, a medical material, a flocculant, a solid fuel binder, a conductive treatment agent, and the like. Furthermore, examples of the optical component include a CD pickup lens, a DVD pickup lens, a Fax lens, an LBP lens, an oligon mirror, and a prism.

  The soluble polyfunctional vinyl aromatic copolymer of the present invention is a resin with improved optical properties, heat resistance, heat discoloration, heat decomposition resistance and processability. Moreover, according to the production method of the present invention, the soluble polyfunctional vinyl aromatic copolymer can be produced with high efficiency.

  EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, all the parts in each example are parts by weight. Moreover, the measurement of the softening temperature etc. in an Example performed sample preparation and a measurement with the method shown below.

1) Molecular weight and molecular weight distribution of polymer GPC (manufactured by Tosoh Corporation, HLC-8120GPC) was used for measuring the molecular weight and molecular weight distribution of the soluble polyfunctional vinyl aromatic copolymer, solvent: tetrahydrofuran (THF), flow rate: 1.0 ml / min, column temperature: 40 ° C. The molecular weight of the copolymer was measured as a molecular weight in terms of polystyrene using a calibration curve with monodisperse polystyrene.

2) Polymer structure Determined by ¹³ C-NMR and ¹ H-NMR analysis using a JNM-LA600 nuclear magnetic resonance spectrometer manufactured by JEOL. Using chloroform -d ₁ as a solvent, was used resonance line of tetramethylsilane as an internal standard.

3) Sample preparation and measurement of glass transition temperature (Tg) and softening temperature measurement A soluble polyfunctional vinyl aromatic copolymer solution was uniformly applied to a glass substrate so that the thickness after drying was 20 μm, and then hot The plate was heated at 90 ° C. for 30 minutes and dried. The obtained resin film on the glass substrate is set in a TMA (thermomechanical analyzer) measuring device together with the glass substrate, heated to 220 ° C. at a temperature rising rate of 10 ° C./min under a nitrogen stream, and further 220 ° C. The remaining solvent was removed by heat treatment for 20 minutes. After allowing the glass substrate to cool to room temperature, the measurement probe is brought into contact with the sample in the TMA measuring apparatus, and measurement is performed by scanning from 30 ° C. to 360 ° C. at a temperature rising rate of 10 ° C./min under a nitrogen stream. The softening temperature was determined by the tangential method. If the probe does not penetrate the resin film due to the heat resistance of the sample and does not show a probe penetration depth smaller than the film thickness, in addition to the softening temperature, the penetration rate for the probe penetration temperature and film thickness is expressed as a percentage. displayed.

4) Measurement of thermal decomposition temperature and carbonization yield Measurement of thermal decomposition temperature and heat discoloration resistance of soluble polyfunctional vinyl aromatic copolymer was performed by placing the sample on a TGA (thermobalance) measuring device and raising the temperature in a nitrogen stream. Measurement is performed by scanning from 30 ° C. to 320 ° C. at a rate of 10 ° C./min, and the weight loss at 300 ° C. is obtained, and the amount of discoloration of the sample after measurement is visually confirmed. A: Thermal discoloration None, B: Pale yellow, C: Brown, D: Black were evaluated for heat discoloration.

5) Measurement of solvent resistance The solvent resistance of the soluble polyfunctional vinyl aromatic copolymer was measured by immersing a vacuum press-molded sample plate in toluene at room temperature for 10 minutes, and visually checking changes in the sample after immersion. The solvent resistance was evaluated by classifying as follows: A: no change, B: swelling, C: deformation and swelling.

6) Measurement of solder heat resistance The solder heat resistance of the soluble polyfunctional vinyl aromatic copolymer is measured by immersing the sample plate subjected to vacuum press molding in 260 ° C lead-free solder for 1 minute, The changes were visually confirmed, and the solder heat resistance was evaluated by classifying them as A: no change, B: warpage, and C: deformation / swelling.

  2.0 mol (377.2 ml) of ethylene dimethacrylate, 8.0 mol (916.6 ml) of styrene, 1.0 mol (235.3 ml) of tert-dodecyl mercaptan, 2,2,6,6-tetramethylpiperidine- 12.0 mmol (1.88 g) of 1-oxyl (TEMPO) was put into a 3.0 L reactor, 20.0 mmol of benzoyl peroxide was added at 90 ° C., and the mixture was reacted for 6 hours. After stopping the polymerization reaction by cooling, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained copolymer was washed with methanol, filtered, dried and weighed to obtain 519.0 g of copolymer A (yield: 30.1 wt%).

Mw of the obtained copolymer A was 30300, Mn was 3410, and Mw / Mn was 8.87. By performing ¹³ C-NMR, ¹ H-NMR analysis and elemental analysis, the copolymer A has a total of 21.2 mol% of structural units derived from ethylene dimethacrylate and a total of 78.8 mol of structural units derived from styrene. % Content. Further, the structural unit (b1) was contained at 14.1 mol%. Copolymer A was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and no gel was formed. The cast film of copolymer A was a transparent film without fogging.

Copolymer A was placed in a mold through a 2.0 mm spacer and cured at 200 ° C. for 1 hour. The obtained cured sheet was cut out, and optical properties and tensile properties were measured and thermal analysis was performed. As a result, total light transmittance: 91.2%, refractive index: 1.582, linear expansion coefficient: 88 ppm / ° C., water absorption: 0.15%, solvent resistance: A, solder heat resistance: A, tensile strength : 3.12kgf / mm ^2, tensile elongation at break: 4.3%, tensile modulus: was 292kgf / mm ^2.
Moreover, the softening temperature was 300 degreeC or more as a result of the TMA measurement. As a result of TGA measurement, the weight loss at 300 ° C. was 0.3 wt%, and the heat discoloration resistance was A.

  2.0 mol (445.8 ml) of 1,4-butanediol dimethacrylate, 8.0 mol (916.6 ml) of styrene, 1.0 mol (235.3 ml) of tert-dodecyl mercaptan, 2,2,6,6 -12.0 mmol (1.88 g) of tetramethylpiperidine-1-oxyl (TEMPO) was charged into a 3.0 L reactor, and 20.0 mmol of benzoyl peroxide was added at 90 ° C for 2.5 hours. Reacted. After stopping the polymerization reaction 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, dried and weighed to obtain 92.3 g of copolymer B (yield: 22.8 wt%).

  Mw of the obtained copolymer B was 8340, Mn was 4040, and Mw / Mn was 2.06. Copolymer B contained a total of 22.1 mol% of structural units derived from 1,4-butanediol dimethacrylate and a total of 77.9 mol% of structural units derived from styrene. Moreover, 15.8 mol% of structural units (b1) were contained. Copolymer B was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and no gel was formed. Further, the cast film of the copolymer B was a transparent film without fogging.

Copolymer B was put into a mold through a 2.0 mm spacer and cured at 200 ° C. for 1 hour. The obtained cured sheet was cut out, and optical properties and tensile properties were measured and thermal analysis was performed. As a result, total light transmittance: 90.6%, refractive index: 1.581, linear expansion coefficient: 92 ppm / ° C., water absorption: 0.1%, solvent resistance: A, solder heat resistance: A, tensile strength : 3.07kgf / mm ^2, tensile elongation at break: 4.9%, tensile modulus: was 289kgf / mm ^2.
Moreover, the softening temperature was 300 degreeC or more as a result of the TMA measurement. As a result of TGA measurement, the weight loss at 300 ° C. was 0.3 wt%, and the heat discoloration resistance was A.

Comparative Example 1
Characteristic evaluation was performed using Estyrene MS-200 (styrene content: 79.8 mol%, MMA content: 20.2 mol%) manufactured by Nippon Steel Chemical Co., Ltd. as a copolymer composed of styrene and methyl methacrylate. went. MS-200 was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and no gel component was observed. Moreover, the cast film of MS-200 was a transparent film without fogging.

MS-200 was placed in a mold through a 2.0 mm spacer and subjected to press molding at 200 ° C. for 20 minutes. The obtained cured sheet was cut out, and optical properties and tensile properties were measured and thermal analysis was performed. As a result, total light transmittance: 90.1%, refractive index: 1.571, linear expansion coefficient: 83 ppm / ° C., water absorption: 0.1%, solvent resistance: C, solder heat resistance: C, tensile strength : 2.89kgf / mm ^2, tensile elongation at break: 3.0%, tensile modulus: was 311kgf / mm ^2.
Moreover, the softening temperature was 98 degreeC as a result of the TMA measurement. As a result of TGA measurement, the weight loss at 300 ° C. was 1.3 wt%, and the heat discoloration resistance was B.

Comparative Example 2
5.7 mol (811.8 ml) of divinylbenzene, 0.30 mol (42.7 ml) of ethylvinylbenzene, 2.0 mol (229.2 ml) of styrene, 0.02 mol (2.7 ml) of 1-chloroethylbenzene, And 17120 ml of dichloroethane (dielectric constant: 10.3) were put into a 30 L reactor, 0.029 mol of tin tetrachloride was added at 70 ° C., and the mixture was reacted for 3 hours. The polymerization reaction was stopped with 13.0 g of calcium hydroxide, filtered, and washed 3 times with 5 L of distilled water. 1.0 g of butylhydroxytoluene was dissolved in the polymerization solution, and then concentrated at 60 ° C. for 1 hour using an evaporator. 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, dried, and weighed to obtain 542.1 g of copolymer C (yield: 54.8 wt%).

Mw of the obtained copolymer C was 28600, Mn was 5140, and Mw / Mn was 5.56. By performing ¹³ C-NMR and ¹ H-NMR analyses, in the copolymer C, resonance lines derived from the chlorine end and the indane end were observed. Moreover, 74.1 mol% in total of structural units derived from divinylbenzene and 25.9 mol% in total of structural units derived from styrene and structural units derived from ethylvinylbenzene were contained. The vinyl group content contained in the copolymer C was 48.1 mol%. As a result of conducting elemental analysis of the copolymer C, C: 90.2 wt%, H: 7.5 wt%, O: 0.02 wt%, and Cl: 2.1 wt%. Copolymer C was soluble in toluene, xylene, THF, dichloroethane, dichloromethane, and chloroform, and no gel was formed. The cast film of copolymer C was a transparent film without cloudiness.

Copolymer C was placed in a mold through a 2.0 mm spacer and cured at 200 ° C. for 1 hour. The obtained cured sheet was cut out, and optical properties and tensile properties were measured and thermal analysis was performed. As a result, total light transmittance: 88.4%, refractive index: 1.592, linear expansion coefficient: 87 ppm / ° C., water absorption: 0.1%, solvent resistance: A, solder heat resistance: A, tensile strength : 1.57 kgf / mm ² , tensile elongation at break: 2.6%, and tensile modulus: 298 kgf / mm ² .
Moreover, the softening temperature was 300 degreeC or more as a result of the TMA measurement. As a result of TGA measurement, the weight loss at 300 ° C. was 3.6 wt%, and the heat discoloration was D.

  Copolymers A and B obtained in the examples are superior in weight loss and heat discoloration compared to copolymer C, such as total light transmittance, linear expansion coefficient, tensile strength, and tensile elongation at break. The physical properties are also excellent overall.

Claims (4)

Monovinyl aromatic compound and a difunctional (meth) obtained by copolymerizing acrylic acid ester, structural units derived from monovinyl aromatic compound (a) and 2 (meth) structural units derived from an acrylic acid ester (b) The molar fraction of the structural unit (b1) containing a reactive (meth) acrylate group derived from a bifunctional (meth) acrylate ester in the side chain is represented by the following formula:
(B1) / [(a) + (b)] ≧ 0.10
(Wherein, (a), (b) and (b1) respectively the structural unit is (a),. That indicates the number of moles of structural units (b) and structural units (b1)) satisfies the further co weight The coalescence contains 10 to 80 mol% of the structural unit (a) derived from the monovinyl aromatic compound and 90 to 20 mol% of the structural unit (b) derived from the bifunctional (meth) acrylic acid ester. ) And (b) is 70 mol% or more, the number average molecular weight Mn of the copolymer is 500 to 1,000,000, and the molecular weight distribution represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn. A soluble polyfunctional vinyl aromatic copolymer having (Mw / Mn) of 100.0 or less and soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform.
(A) 10-200 parts by weight of one or more chain transfer agents selected from the group consisting of 2,4-diphenyl-4-methyl-1-pentene, thiol compounds and thioether compounds are present with respect to 100 parts by weight of the total monomers. is allowed, the monovinyl aromatic compound 10-80 mol% and a bifunctional (meth) acrylic acid ester containing 90 to 20 mol%, the sum of the monovinyl aromatic compound and a difunctional (meth) acrylic acid ester in the total monomer the method of producing the soluble polyfunctional vinyl aromatic copolymer but which is characterized in that the monomer component Ru der least 70 mole%, is polymerized at a temperature of 50 to 200 ° C..   The monovinyl aromatic compound is one or more monovinyl aromatic compounds selected from the group consisting of styrene and ethylvinylbenzene, and the bifunctional (meth) acrylic ester is ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate , 1,4-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate It is a meth) acrylic acid ester, The manufacturing method of the soluble polyfunctional vinyl aromatic copolymer of Claim 2 characterized by the above-mentioned.   A cured product obtained by thermally curing the soluble polyfunctional vinyl aromatic copolymer according to claim 1.