JP2010007006A - Method for producing vinyl alicyclic hydrocarbon polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a vinyl alicyclic hydrocarbon polymer, which comprises a step of heating a reaction solution containing the vinyl alicyclic hydrocarbon polymer to vaporize/remove a volatile component and in which the amount of the residual volatile component of the vinyl alicyclic hydrocarbon polymer to be obtained can be made extremely small and that of the molecular weight reduction can also be made small. <P>SOLUTION: The method for producing the vinyl alicyclic hydrocarbon polymer comprises the steps of: polymerizing monomers containing a vinyl compound; adding hydrogen, if necessary, to obtain the reaction solution containing the vinyl alicyclic hydrocarbon polymer; adding an antioxidant, satisfying following conditions, to the reaction solution by 0.1-2 parts mass based on 100 parts mass monomers containing the vinyl compound; and heating the antioxidant-added reaction solution to vaporize/remove the volatile component and recover the vinyl alicyclic hydrocarbon polymer. (1), (2) The antioxidant has a phenolic partial structure and a phosphatic partial structure and 90/10 to 10/90 molar ratio of (the phenolic partial structure)/(the phosphatic partial structure). (3) Antioxidant particles having ≥700 molecular weight account for ≥10 mol% of all of antioxidant particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a vinyl alicyclic hydrocarbon polymer suitable as a material for, for example, an optical molded body or a medical molded body, a vinyl alicyclic hydrocarbon polymer obtained thereby, and a molded body.

Vinyl alicyclic hydrocarbon polymers obtained by hydrogenating aromatic vinyl polymers such as polystyrene are excellent in transparency, low water absorption, heat resistance, low adsorptivity, etc., and are suitable for optical materials and medical materials. Is suitable. Vinyl alicyclic hydrocarbon polymer is produced by performing a polymerization reaction by solution polymerization using an organic solvent and then hydrogenating in a reaction solution as necessary, but it is used as an optical material or medical material. For this purpose, it is necessary to remove a volatile component such as an organic solvent from the reaction solution, and then form a molded body by heat-melt molding or the like.
Since vinyl alicyclic hydrocarbon polymer is susceptible to molecular cleavage by heat, the reaction solution is poured into a large amount of solvent (poor solvent) that does not dissolve the polymer to precipitate the polymer, and then the polymer is filtered by filtration. It was recovered (coagulation drying method) and dried at a low temperature to obtain a molding material, but there was a problem that many volatile components remained.
In solving the above problem, WO 02/016447 (Patent Document 1) uses a direct drying method in which a reaction solution dissolved in an inert solvent is heated under reduced pressure to evaporate and remove the inert solvent. Discloses a method for recovering a vinyl alicyclic hydrocarbon polymer. However, although the disclosed method can suppress a decrease in molecular weight due to molecular chain scission of the polymer, a relatively large amount of volatile components remain, and when a polymer is heated and melt-molded, molding of silver streaks, microvoids, etc. Defects may occur, it is difficult to obtain stable and precise optical components, and there are many volatile components for using a molded product for medical purposes, and there are cases where the use is problematic.

WO02 / 016447

An object of the present invention is to provide a method for producing a vinyl alicyclic hydrocarbon polymer capable of extremely reducing the amount of residual volatile components and reducing a decrease in molecular weight, and a vinyl alicyclic hydrocarbon polymer obtained by this method. It is to be.
As a result of diligent research to overcome the problems of the prior art, the present inventors use a specific amount of an antioxidant containing a specific structure when recovering a vinyl cyclic hydrocarbon polymer by direct drying. In order to extremely reduce the amount of volatile components, for example, even if the resin residence time in the dryer apparatus is increased, the decrease in molecular weight due to the molecular chain scission of the polymer can be suppressed, and the volatile components It has been found that a vinyl cyclic hydrocarbon polymer having an extremely small amount and excellent in strength and transparency can be obtained.

（式（１）中、Ｒ^１、Ｒ^２はそれぞれ独立して水素原子、炭素原子数１〜８のアルキル基を表す。）

（式（２）中、Ｘ^１〜Ｘ^２はそれぞれ一価の有機基を表し、またＸ^１とＸ^２とが互いに結合して環構造を形成していても良い。） According to the present invention, a monomer containing a vinyl compound is contained in a reaction solution containing a vinyl alicyclic hydrocarbon polymer obtained by polymerizing a monomer containing a vinyl compound and hydrogenating as necessary. After adding 0.1 to 2 parts by mass of an antioxidant satisfying the following conditions (1) to (3) to 100 parts by mass of the body, the polymer is recovered by heating to evaporate and remove volatile components. A method for producing a vinyl alicyclic hydrocarbon polymer.
(1) The antioxidant has a partial structure represented by the formula (1) and a partial structure represented by the formula (2).
(2) The partial structure represented by formula (1) / the partial structure (molar ratio) represented by formula (2) is 90/10 to 10/90.
(3) In all the antioxidants, the content ratio of the antioxidant having a molecular weight of 700 or more is 10 mol% or more.

(In the formula ^(1), R 1, ^{R 2} are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms.)

(In formula (2), X ^{1 to} X ² each represents a monovalent organic group, and X ¹ and X ² may be bonded to each other to form a ring structure.)

  Further, according to the present invention, the molecular weight of the recovered vinyl alicyclic hydrocarbon polymer is a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography, and is 100,000 or more. In addition, a vinyl alicyclic hydrocarbon polymer having a volatile component content of 10 ppm or less in the vinyl alicyclic hydrocarbon polymer can be produced.

  In the method for producing a vinyl alicyclic hydrocarbon polymer, the reaction solution containing the vinyl alicyclic hydrocarbon polymer is heated to evaporate and remove volatile components to recover the polymer. The amount of volatile components of the hydrogen polymer can be extremely reduced, and the decrease in molecular weight can be reduced. In addition, when such a vinyl alicyclic hydrocarbon polymer is used, a molded product having an extremely low volatile content, no molding defects, high strength, and excellent transparency can be obtained.

Examples of the vinyl alicyclic hydrocarbon polymer according to the present invention include a hydride of an aromatic ring portion of an aromatic vinyl polymer, an alicyclic vinyl polymer, and a hydride of an alicyclic vinyl polymer. It is done.
The method for producing a vinyl alicyclic hydrocarbon polymer according to the present invention comprises a step of polymerizing an aromatic vinyl compound and / or an alicyclic vinyl compound in the presence of a polymerization catalyst, and, if necessary, the polymerization step. It has the process of hydrogenating the polymer obtained in presence of a hydrogenation catalyst, and the volatile component removal process of removing the volatile component of the reaction liquid obtained by the said polymerization process or a hydrogenation process.

(Polymerization process)
The aromatic vinyl compound used in the polymerization step is not particularly limited as long as it is a compound having an aromatic ring and a polymerizable vinyl group. Examples of the aromatic vinyl compound include, for example, styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene, 2-methylstyrene, 3-methylstyrene, List 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, monofluorostyrene, etc. Can do. Among these, styrene and α-methylstyrene are particularly preferable.

Examples of the alicyclic vinyl compound used in the polymerization step include a cycloalkene vinyl compound and a cycloalkane vinyl compound.
The cycloalkene vinyl compound is not particularly limited as long as it is a compound having a C5-C8 aliphatic ring having a double bond and a polymerizable vinyl group. The aliphatic ring can have an alkyl group having 1 to 4 carbon atoms or a halogen atom group as a substituent. Examples of the cycloalkene vinyl compound include, for example, cyclopentene vinyl compounds such as 2-vinylcyclopentene, 2-methyl-4-vinylpentene, 3-vinylcyclopentene, 3-t-butyl-4-vinylpentene; 4-vinylcyclohexene Cyclohexene such as 4-isopropenyl vinylcyclohexene, 1-methyl-4-vinylcyclohexene, 1-methyl-4-isopropenyl vinylcyclohexene, 2-methyl-4-vinylcyclohexene, 2-methyl-4-isopropenyl vinylcyclohexene Vinyl compounds; 2-vinylcycloheptene, 3-vinylcycloheptene, 4-vinylcycloheptene, 3-methyl-6-vinylcycloheptene, 4-ethyl-6-vinylcycloheptene, 3-t- Butyl-5-vinylcyclo Cycloheptene vinyl compounds such as butene; 2-vinylcyclooctene, 3-vinylcyclooctene, 4-vinylcyclooctene, 2-methyl-5-vinylcyclooctene, 4-ethyl-6-vinylcyclooctene, 3-t And cyclooctene vinyl compounds such as -butyl-7-vinylcyclooctene. Among these, a cyclopentene vinyl compound and a cyclohexene vinyl compound are preferable, and a cyclohexene vinyl compound is particularly preferable.

  The cycloalkane vinyl compound is not particularly limited as long as it is a compound having a saturated aliphatic ring having 5 to 8 carbon atoms and a polymerizable vinyl group. The aliphatic ring can have an alkyl group having 1 to 4 carbon atoms or a halogen atom group as a substituent. Examples of cycloalkane vinyl compounds include cyclopentane vinyl compounds such as 2-vinyl cyclopentane, 2-methyl-4-vinyl pentane, 3-vinyl cyclopentane, 3-t-butyl-4-vinyl pentane; 4-vinyl Such as cyclohexane, 4-isopropenyl vinylcyclohexane, 1-methyl-4-vinylcyclohexane, 1-methyl-4-isopropenyl vinylcyclohexane, 2-methyl-4-vinylcyclohexane, 2-methyl-4-isopropenyl vinylcyclohexane, etc. Cyclohexane vinyl compound; 2-vinylcycloheptane, 3-vinylcycloheptane, 4-vinylcycloheptane, 3-methyl-6-vinylcycloheptane, 4-ethyl-6-vinylcycloheptane, 3-t-butyl-5 Vinylcycloheptane Of cycloheptane vinyl compounds; 2-vinylcyclooctane, 3-vinylcyclooctane, 4-vinylcyclooctane, 2-methyl-5-vinylcyclooctane, 4-ethyl-6-vinylcyclooctane, 3-t-butyl- Examples include cyclooctane vinyl compounds such as 7-vinylcyclooctane. Among these, a cyclopentane vinyl compound and a cyclohexane vinyl compound are preferable, and a cyclohexane vinyl compound is particularly preferable.

  Among these compounds, aromatic vinyl compounds, cyclopentene vinyl compounds, and cyclohexene vinyl compounds are preferable, and aromatic vinyl compounds and cyclohexene vinyl compounds are more preferable. These compounds can be used alone or in combination of two or more.

In addition to the aromatic vinyl compound and / or the alicyclic vinyl compound, a monomer copolymerizable therewith may be added. Such a monomer is not particularly limited as long as it can be copolymerized by a polymerization method such as radical polymerization, anionic polymerization, or cationic polymerization. For example, ethylene, propylene, isobutene, 2-methyl-1-butene Α-olefin monomers such as 2-methyl-1-pentene and 4-methyl-1-pentene; cyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene, 2-ethylcyclopentadiene, 5-methyl Cyclopentadiene monomers such as cyclopentadiene and 5,5-dimethylcyclopentadiene; Cyclic olefin monomers such as cyclobutene, cyclopentene, cyclohexene and dicyclopentadiene; butadiene, isoprene, 1,3-pentadiene, furan and thiophene 1,3-hexadiene, etc. Conjugated diene monomers; nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile; methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, acrylic Acrylic acid ester monomers such as propyl acid and butyl acrylate; unsaturated fatty acid monomers such as acrylic acid, methacrylic acid and maleic anhydride; phenylmaleimide; ethylene oxide, propylene oxide, trimethylene oxide, trioxane, Cyclic ether monomers such as dioxane, cyclohexene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran; methyl vinyl ether, N-vinyl carbazole, N-vinyl-2-pyrrolidone, etc. Such heterocyclic containing vinyl compound monomer. These copolymerizable monomers can be used alone or in combination of two or more. When a copolymerizable monomer is added, it may be added in a range where the repeating unit in the polymer is 50% by weight or less.
When an aromatic vinyl compound and / or an alicyclic vinyl compound and the above copolymerizable monomer are copolymerized, the resulting copolymer includes a random copolymer, a pseudo-random copolymer, and a graft copolymer. A polymer, a block copolymer, etc. are mentioned. In the case of a block copolymer, it may have a diblock, triblock, or more multiblock, a star-like branched structure, or a block copolymer having an inclined block.

The mode of the polymerization reaction may be any of known methods such as radical polymerization, anionic polymerization, and cationic polymerization, and may be any of suspension polymerization, solution polymerization, and bulk polymerization.
When performing radical polymerization, a radical initiator such as azobisisobutyronitrile or benzoyl peroxide can be used as a polymerization catalyst.
When cationic polymerization is performed, BF ₃ or BF ₆ can be used as a polymerization catalyst.
When anionic polymerization is performed, an organic alkali metal can be used as a polymerization catalyst.

  When the hydrogenation reaction is continuously performed after the polymerization reaction, solution polymerization in which polymerization is performed in an organic solvent is convenient for performing the process continuously. In order to obtain a polymer having a narrower molecular weight distribution, which is preferable as a polymer having a smaller birefringence, anionic polymerization is preferred.

  The organic solvent is preferably a hydrocarbon solvent and is not particularly limited as long as it does not harm the polymerization catalyst. For example, fats such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, isooctane, etc. Aromatic hydrocarbons such as cyclopentane, cyclohexane and decalin; aromatic hydrocarbons such as benzene and toluene; ethers such as tetrahydrofuran and dioxane. Among these, aliphatic hydrocarbons and alicyclic hydrocarbons are preferable because they can be used as a solvent for the hydrogenation reaction after the polymerization reaction. These organic solvents can be used alone or in combination of two or more. The amount of the organic solvent used is such that the monomer concentration is usually 1 to 40% by mass, preferably 10 to 30% by mass.

Examples of the organic alkali metal used for anionic polymerization include mono-organic lithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1, Polyfunctional organolithium compounds such as 4-dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organolithium compound is preferable, and monoorganolithium is particularly preferable. These organic alkali metals can be used alone or in combination of two or more. The usage-amount of an organic alkali metal is 0.01-100 mass parts normally per 100 mass parts of monomers, Preferably it is 0.02-1 mass parts.
In anionic polymerization, if desired, a Lewis base can be added to the polymerization catalyst in order to obtain a polymer having a narrow molecular weight distribution.

  Examples of the Lewis base include ether compounds such as diethyl ether, dibutyl ether, methyl ethyl ether, dibenzyl ether, and tetrahydrofuran: tertiary amine compounds such as tetramethyl ethylene diamine, triethyl amine, and pyridine; potassium tert-amyl oxide, potassium -Alkyl metal alkoxide compounds such as t-butyl oxide; and phosphine compounds such as triphenylphosphine. Among these, ether compounds are particularly preferable because they produce a polymer having a narrow molecular weight distribution. These Lewis base compounds can be used alone or in combination of two or more. The amount of the Lewis base compound used is usually 0.01 to 10-fold mol amount, preferably 0.1 to 5.0-fold mol amount based on the organic alkali metal.

The polymerization reaction is usually carried out at -70 to 150 ° C, preferably -50 to 120 ° C. The polymerization time is usually 0.01 to 20 hours, preferably 0.1 to 10 hours.
The polymerization reaction is stopped when the polymerization conversion rate is high and the monomer is substantially lost, but a polymerization catalyst deactivator may be added for the purpose of preventing gelation of the reaction solution after the polymerization reaction. . Examples of the deactivation agent for the polymerization catalyst include water; alcohols such as methanol, ethanol, isopropyl alcohol, 1,2-butanediol, and glycerin; carboxylic acids such as formic acid, acetic acid, citric acid, and phthalic acid; phenol, Examples thereof include phenols such as cresol.
The molecular weight of the polymer obtained in the polymerization step is appropriately selected according to the purpose of use, but from the viewpoint of the balance between mechanical strength and molding processability, standard polystyrene measured by gel permeation chromatography of tetrahydrofuran solution The converted weight average molecular weight (Mw) is preferably 100,000 to 300,000, more preferably 100,000 to 250,000, and still more preferably 100,000 to 200,000. When the molecular weight is excessively large, not only the moldability is deteriorated but also the hydrogenation reaction proceeds slowly when the hydrogenation described later is performed, and the hydrogenation rate is lowered. On the other hand, if the molecular weight is excessively small, the mechanical strength of the polymer decreases.

The glass transition temperature (Tg) of the polymer obtained in the polymerization step is usually 50 to 250 ° C, preferably 70 to 220 ° C, more preferably 100 to 200 ° C.
The polymer obtained by the polymerization step does not have a carbon-carbon unsaturated bond (non-conjugated unsaturated bond and / or aromatic unsaturated bond, etc .; the same applies hereinafter) in the side chain ring, which will be described later. When not performing a hydrogenation process, it is preferable to include the process of removing a polymerization catalyst from the reaction liquid after the said polymerization process. Even when the hydrogenation step is performed, a polymerization catalyst removal step may be included after the polymerization step. As a method of removing the polymerization catalyst in the case of solution polymerization, a method of adding an adsorbent such as activated alumina to the polymerization reaction liquid and stirring in a heated state, adsorbing the polymerization catalyst on the adsorbent and removing by filtration, Examples thereof include a method of adding a small amount of isopropyl alcohol or the like to the polymerization reaction solution to precipitate the polymerization catalyst and removing it by filtration. The catalyst residual amount in the reaction solution after removing the catalyst is usually 10 ppm or less, preferably 1 ppm or less, based on the weight of the metal element derived from the catalyst with respect to the polymer in the reaction solution.

(Hydrogenation process)
In this invention, when the polymer obtained by the said polymerization process has a carbon-carbon unsaturated bond in the ring of a side chain, it is preferable to hydrogenate a part or all of the unsaturated group. Hydrogenation of unsaturated groups can improve the heat resistance and transparency of the polymer.
The hydrogenation reaction is performed by bringing the polymer into contact with hydrogen in the presence of a hydrogenation catalyst according to a conventional method.
The hydrogenation catalyst contains, for example, at least one element selected from nickel, cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium and rhenium.
Examples of the carrier include activated carbon, diatomaceous earth, magnesia, silica, alumina, silica-magnesia, diatomaceous earth-alumina, silica-zirconia, diatomaceous earth-zirconia, and alumina-zirconia. The amount of the metal supported on the carrier is usually 0.01 to 80% by mass.
Examples of homogeneous catalysts include catalysts in which a metal compound such as nickel, cobalt, titanium or iron and an organometallic compound such as organoaluminum or organolithium are combined; organometallic complexes such as rhodium, palladium, ruthenium and rhenium Etc. can be used. As the metal compound, for example, acetylacetone salt, naphthenate salt, cyclopentadienyl compound, cyclopentadienyl dichloro compound and the like of each metal are used. As the organic aluminum, alkyl aluminum such as triethylaluminum and triisobutylaluminum; alkylaluminum halide such as diethylaluminum chloride and ethylaluminum dichloride; alkylaluminum hydride such as diisobutylaluminum hydride and the like are used. Examples of organometallic complexes include γ-dichloro-π-benzene complexes, dichloro-tris (triphenylphosphine) complexes, hydrido-chloro-tris (triphenylphosphine) complexes of the above metals.
These hydrogenation catalysts can be used alone or in combination of two or more. The usage-amount of a hydrogenation catalyst is 0.1-50 mass parts normally per 100 mass parts of polymers, Preferably it is 1-20 mass parts.

Examples of the organic solvent used in the hydrogenation step include alcohols in addition to the solvent used in the solution polymerization described above. These organic solvents can be used alone or in combination of two or more. The amount of the organic solvent used is such that the polymer concentration in the reaction solution is usually 1 to 50% by mass, preferably 3 to 40% by mass.
The hydrogenation reaction of the polymer is carried out by introducing hydrogen into the hydrogenation reaction liquid. For example, there is a method in which hydrogen introduced under stirring of an organic solvent solution of the polymer is sufficiently brought into contact with the polymer. preferable.
The temperature of the hydrogenation reaction is usually 10 to 250 ° C, preferably 50 to 200 ° C. The hydrogen pressure is usually 0.1 to 30 MPa, preferably 1 to 10 MPa.
After hydrogenation, it is preferable to add a filter aid to the reaction solution, filter the hydrogenation catalyst and filter aid, and use them in the next hydrogenation step.
Filter aids are chemically inert, porous particles that are used to keep the material to be filtered from clogging the filter media. Examples of the filter aid include inert powders such as diatomaceous earth, silica, synthetic zeolite, perlite, and radiolite that are insoluble in a solvent. Examples of how to use the filter aid include a body feed method in which the filter aid is added in advance to the suspension to be filtered, and a precoat method in which a filter aid bed is formed on the filter medium and then filtered. The body feed method is preferred. The amount of filter aid used is preferably the same as that of the hydrogenation catalyst. In the hydrogenation reaction of the next batch (batch) of the polymer, it is possible to save the amount of catalyst used by using the recovered hydrogenation catalyst as a hydrogenation catalyst in a state where the filter aid is mixed. preferable. If necessary, a new hydrogenation catalyst or a filter aid may be supplemented in addition to the recovered hydrogenation catalyst. Although the cause is not clear, the reduction of the hydrogenation rate can be prevented if the filter aid remains mixed.

The molecular weight of the polymer obtained in the hydrogenation step is appropriately selected depending on the purpose of use, but is Mw in terms of standard polystyrene measured by gel permeation chromatography of a tetrahydrofuran solution, preferably 100,000 to 300. 1,000, more preferably 100,000 to 250,000, and still more preferably 100,000 to 200,000.
The Tg of the polymer obtained in the hydrogenation step is usually 50 to 250 ° C, preferably 70 to 220 ° C, more preferably 100 to 200 ° C.
In the present invention, it is preferable to include a step of removing the hydrogenation catalyst from the reaction solution after the hydrogenation step, but without performing the polymerization catalyst removal step, both the polymerization catalyst and the hydrogenation catalyst are added after the hydrogenation step. It is good also as removing at once. The method for removing the catalyst, the residual amount of the catalyst after removal, and the like are the same as in the polymerization catalyst removal step.

(Addition of antioxidant)
In the present invention, an antioxidant is added to the reaction solution after the polymerization step or the hydrogenation step before removing the volatile component mainly composed of the organic solvent from the reaction solution after the polymerization step or the hydrogenation step.

  The antioxidant used in the present invention includes a partial structure represented by the formula (1) (hereinafter referred to as “structure (A)”) and a partial structure represented by the formula (2) (hereinafter referred to as “structure”). (B) "). The two structures may be present in one compound or in different compounds. One or more of these structures may be present in one molecule of the antioxidant. Specifically, an antioxidant having only the structure (A) and an antioxidant having only the structure (B) may be mixed and used, or the antioxidant having the structure (A) and the structure (B). Only an agent may be used, an antioxidant having the structure (A) and the structure (B) and an antioxidant having only the structure (A) may be used in combination, or the structure (A) and You may mix and use the antioxidant which has a structure (B), and the antioxidant which has only a structure (B). Of course, a combination of two or more antioxidants having the same structure, such as a combination of two types of antioxidants having only the structure (A) and an antioxidant having the structure (A) and the structure (B). it can.

In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. In the formula (2), X ^{1 to} X ² Each represents a monovalent organic group, and X ¹ and X ² may be bonded to each other to form a ring structure.
As the monovalent organic group, those having an aromatic ring are preferable, and a phenyl group which may have a substituent, a benzyl group which may have a substituent, and an alkyl group having these may be mentioned as preferred specific examples. It is done.

  Examples of the antioxidant having the structure (A) include, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4 -Di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, such as JP-A 63-179953 and JP-A 1-168643 Acrylate compounds described in the publication; 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, octadecyl-3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4-butylidene-bis (6-tert-butyl-m-cle) ), 4,4′-thiobis (3-methyl-6-tert-butylphenol), bis (3-cyclohexyl-2-hydroxy-5-methylphenyl) methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,1, 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy Benzyl) benzene, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane [ie pentaerythrityl-tetrakis [3- (3,5 Di-t-butyl-4-hydroxyphenyl) propionate]], triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate), tocopherol and other alkyl-substituted phenolic compounds; 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bis-octylthio-1,3,5-triazine, 6- (4-hydroxy-3,5-dimethylanilino)- 2,4-bis-octylthio-1,3,5-triazine, 6- (4-hydroxy-3-methyl-5-t-butylanilino) -2,4-bis-octylthio-1,3,5-triazine, Triazine group-containing phenols such as 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine And the like.

  Examples of the antioxidant having the structure (B) include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2 , 4-di-t-butylphenyl) phosphite, tris (2-t-butyl-4-methylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, 2,2-methylenebis (4,6-di-t -Butylphenyl) octyl phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10 -Dihydro-9-oxa-10-phosphaphenanthrene-10-oxai Monophosphite compounds such as 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-) Tridecyl phosphite), 4,4′-isopropylidene-bis (phenyl-di-alkyl phosphite) (carbon number of the alkyl moiety: 12 to 15), 4,4′-isopropylidene-bis (diphenyl monoalkyl phosphite) ) (Carbon number of alkyl moiety: 12 to 15), 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, tetrakis (2,4-di-) t-butylphenyl) -4,4′-biphenylene diphosphite, cyclic neopentanetetrayl-bis (octadecyl phosphite) Cyclic neopentanetetrayl-bis (isodecyl phosphite), cyclic neopentanetetrayl-bis (nonylphenyl phosphite), cyclic neopentanetetrayl-bis (2,4-di-t-butylphenylphosphine) Phosphite), cyclic neopentanetetrayl-bis (2,4-dimethylphenylphosphite), cyclic neopentanetetrayl-bis (2,6-di-t-butylphenylphosphite) Is mentioned.

  Examples of the antioxidant having the structure (A) and the structure (B) include 6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10. -Tetrakis-t-butyldibenzo [d, f] [1.3.2] dioxaphosphine, 6- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propoxy] -2 4,8,10-tetrakis-t-butyldibenzo [d, f] [1.3.2] dioxaphosphine.

The ratio (molar ratio) of the structure (A) / structure (B) in the antioxidant is 90/10 to 10/90, preferably 90/10 to 30/70, more preferably 90/10 to 50/50. Particularly preferred is 85/15 to 60/40. Within such a range, a decrease in molecular weight is suppressed in the volatile component removal step described below, and the resulting molded article is excellent in transparency and preferable.
If there are four structures (A) in one antioxidant, the number of moles of structure (A) is calculated as four times the number of moles of antioxidant. If there is one structure (A) and one structure (B) in one antioxidant, the number of moles of structure (A) and the number of moles of structure (B) are respectively equal to the number of moles of antioxidant. Become.

  The antioxidant having a molecular weight of 700 or more contained in the antioxidant containing the structure (A) and the structure (B) is 10 mol% or more, preferably 30 mol% or more, more preferably 50 mol% or more. When it exists in such a range, in the following volatile component removal process, since the said antioxidant is hard to volatilize and it is excellent in the inhibitory effect of the fall of molecular weight, it is preferable.

The antioxidant is used in an amount of 0.1 to 2 parts by weight, preferably 0.2 to 1 part by weight based on 100 parts by weight of the total amount of monomers containing vinyl compounds, which are raw materials for the vinyl alicyclic polymer. It is 5 mass parts, More preferably, it is 0.3-1 mass part. Within such a range, a decrease in molecular weight is suppressed in the volatile component removal step described below, and the resulting molded article is excellent in transparency and preferable.
In addition to the above antioxidants, known sulfur-based antioxidants, lactone-based antioxidants, and the like can be used as long as the object of the present invention is not impaired.

(Volatile component removal process)
Next, the reaction solution after the above-described polymerization step or hydrogenation step is supplied from an external environment to a closed system in which foreign matters are not mixed, and volatile components mainly composed of an organic solvent are removed from the reaction solution so Collect the coalesced. In addition, it is also preferable that the solvent removed by evaporation is liquefied and recovered by a condensing device and reused.

  The removal of the volatile component in the present invention uses a direct drying method in which the solvent and other volatile components are evaporated and removed by heating.

  Depressurized solvent removal devices that can be directly dried include vented screw extruders and thin film dryers, but considering the decrease in polymer molecular weight caused by mechanical stress, A thin film drier having a small shear stress applied to the coalescence is preferable, and a solvent removing apparatus capable of reducing pressure without a thin film stirrer and having a heat exchanger (for example, a solvent removing apparatus capable of reducing pressure with a plate fin type heat exchanger, etc. ) Is particularly preferred because no shear stress is applied to the polymer in the solution. Examples of the solvent removing apparatus that can be depressurized without a thin film stirrer and a heat exchanger include a hibiscus evaporator (manufactured by Mitsui Engineering & Shipbuilding).

  The lower limit of the heating temperature for the reaction solution is the glass transition temperature (Tg) of the polymer contained in the reaction solution + 50 ° C., and the upper limit is preferably 320 ° C., more preferably 240 ° C. or more and 280 ° C. or less. is there. If the heating temperature of the reaction solution is too low, the evaporation efficiency is deteriorated, resulting in problems such as a decrease in productivity and thermal deterioration of the polymer. If the heating temperature is too high, the recovered polymer may be thermally deteriorated to cause a decrease in molecular weight.

  The heating is usually performed under normal pressure or reduced pressure. The operating pressure at the time of heating the reaction solution, that is, the pressure in the container is preferred in that the lower the volatile component removing effect is, the more preferred is 15 kPa or less, and even more preferred is 5 kPa or less. When the operating pressure is too high, the evaporation efficiency of the solution is deteriorated, and the content of volatile components in the polymer after drying is increased.

  From the start of heating the reaction solution (specifically, after being introduced into the solvent removal apparatus capable of depressurization), until the polymer is recovered (specifically, for example, derived from the solvent removal apparatus) The time (from the time until it is cooled and solidified and then pelletized) (residence time in the apparatus) is preferably 10 hours or less, more preferably 5 hours or less. If the residence time in the apparatus is too long, the polymer to be recovered may be thermally deteriorated to cause a decrease in molecular weight. In order to reduce the amount of volatile components in the polymer, the residence time of the polymer in the apparatus is preferably 1 hour or longer, more preferably 3 hours or longer.

  In the direct drying in the present invention, two or more solvent-removable apparatuses that can be depressurized may be used. In this case, different operation pressures and heating temperatures may be used for each apparatus.

  If the polymer concentration of the reaction liquid supplied to the volatile component removal step and heated under normal pressure or reduced pressure is less than 80%, a part of the volatile component contained in the reaction liquid is removed. It is preferable to further have a step (preliminary concentration step) of preliminarily concentrating so that the polymer concentration is 80% or higher, preferably 85% or higher. The preconcentration method is not particularly limited, and is a method of concentrating only by placing the reaction solution under normal pressure; a method of concentrating the reaction solution by heating under normal pressure (heating concentration method); The reaction solution is released into the system at normal pressure, and only the volatile components are scattered and separated by the pressure difference to concentrate the reaction solution (flash concentration method). The flash concentration method is preferable from the viewpoint of good properties, and the heat flash concentration method combining the heat concentration method and the flash concentration method is particularly preferable. Examples of the apparatus used for the flash concentration method include a flash box and a flash separator.

  In addition, even when performing preconcentration, it is good also as having the process (preheating process) of heating a reaction liquid beforehand before preconcentration. By preheating the reaction solution before preconcentration, the concentration efficiency of the polymer is improved. As a preheating method, a method of heating a storage container for a reaction solution before concentration and / or a transfer pipe from the storage container to a solvent removal device with a jacket type heating device, a multi-tube heat exchanger or a plate Examples thereof include a method using a known heat exchanger such as a fin type heat exchanger. The temperature of the solution during the preheating is usually 50 to 400 ° C, preferably 70 to 350 ° C.

  In the present invention, it is preferable to remove the volatile components described above in a low oxygen concentration atmosphere. By performing in a low oxygen concentration atmosphere, coloring of the finally recovered polymer can be effectively prevented. The low oxygen concentration atmosphere is preferably adjusted so that the oxygen concentration is 10% by volume or less, more preferably 8% by volume or less. By setting the working atmosphere to a lower oxygen concentration, oxidation of the polymer is prevented and coloring of the resulting molded product is prevented. Specific means for creating a low oxygen concentration atmosphere include a method in which the inside of the apparatus used for removing volatile components is an inert gas atmosphere such as nitrogen or helium.

  By passing through the volatile component removal step as described above, the volatile component content in the recovered polymer can be preferably 10 ppm or less, more preferably 5 ppm or less. Here, the volatile component refers to a component having a boiling point of 200 ° C. or less at normal pressure, and the volatile content in the polymer can be analyzed by gas chromatography. A polymer having a volatile component content in the above range can suppress the occurrence of molding defects such as silver streak and microd, and can stably obtain a precise optical component, and has been obtained using the polymer. Since the molded product has an extremely small amount of volatile components, it can be suitably used for medical applications.

  Further, the Mw of the polymer to be recovered is preferably 100,000 or more, more preferably 110,000 or more, and further preferably 120,000 or more. Incidentally, the upper limit of Mw is usually 300,000 or less, preferably 200,000 or less. A polymer having a molecular weight in the above range can provide a molded article having excellent strength.

(Various compounding agents)
Various compounding agents can be added to the vinyl alicyclic hydrocarbon polymer obtained by the method of the present invention as required. Various compounding agents are not particularly limited as long as they are generally used in the resin industry. For example, antioxidants such as phenols, phosphites, and thioethers; UV absorptions such as hindered phenols Agents: Aliphatic alcohols, aliphatic esters, aromatic esters, triglycerides, release agents such as fluorosurfactants, higher fatty acid metal salts; other lubricants, antifogging agents, plasticizers, pigments, near infrared absorption Agents, antistatic agents and the like. These compounding agents are used alone or in combination of two or more. The usage-amount of a compounding agent is suitably selected in the range which does not impair the range of this invention.
Vinyl alicyclic hydrocarbon polymers to which various compounding agents are added are used alone or in combination of two or more.

(Molding)
The vinyl alicyclic hydrocarbon polymer obtained by the method of the present invention can be kneaded in a molten state such as a twin screw extruder after production and used as pellets. And it can be molded by known methods such as injection molding, extrusion molding, cast molding, inflation molding, blow molding, vacuum molding, press molding, compression molding, rotational molding, calendar molding, rolling molding, cutting molding, etc. it can.
The vinyl alicyclic hydrocarbon polymer obtained by the method of the present invention is excellent in transparency. This can be confirmed by measuring the light transmittance at 400 nm of the vinyl alicyclic hydrocarbon polymer having a thickness of 3 mm, a length of 65 mm, and a width of 65 mm, preferably 87% or more, more preferably 88. % Or more, more preferably 89% or more, and particularly preferably 90%.

(Use)
The vinyl alicyclic hydrocarbon polymer obtained by the method of the present invention is useful in a wide range of fields as various molded articles including optical materials and medical materials.
For example, optical materials such as optical disks, optical lenses, prisms, light diffusion plates, optical cards, optical fibers, optical mirrors, liquid crystal display element substrates, light guide plates, polarizing films, retardation films, etc .; liquid chemical containers, ampoules, vials, prefilled syringes , Infusion bags, sealed medicine bags, press-through packages, solid medicine containers, eye drops containers and other liquid, powder, or solid medicine containers, food containers, blood test sampling tubes, chemical container caps, sampling Blood vessels, sampling containers such as specimen containers, medical instruments such as syringes, sterile containers such as medical instruments such as scalpels, forceps, gauze and contact lenses, experimental and analytical instruments such as beakers, petri dishes, flasks, test tubes, centrifuge tubes, Medical optical parts such as plastic lenses for medical examinations, medical infusion tubes, piping, joints , Piping materials such as valves, medical equipment such as artificial teeth and parts such as denture bases, artificial hearts and artificial tooth roots; containers for processing or transferring tanks, trays, carriers, cases, carrier tapes, separation films Protective materials such as pipes, tubes, valves, pipes such as sipper flowmeters, filters, pumps, electronic parts processing equipment such as sampling containers, liquid containers such as bottles, ampule bags, etc .; General insulating materials such as consumer / industrial electronic equipment, OA equipment such as copiers, computers and printers, instruments, etc .; circuit boards such as rigid printed boards, flexible printed boards, multilayer printed wiring boards, especially high frequency characteristics are required High-frequency circuit boards for satellite communications equipment; liquid crystal substrates, optical memories, automobiles and aviation Transparent conductive film base materials such as surface heating elements such as defrosters, electrical and conductive sealing materials and parts such as transistors, ICs, LSIs, and LEDs, and sealing of electrical and electronic parts such as motors, capacitors, switches, and sensors Electrical insulation materials such as fixing materials, body materials such as TVs and video cameras, parabolic antennas, flat antennas, radar dome structural members; films such as packaging films and agricultural films; for information recording such as magnetic flexible disks and magnetic hard disks Examples include substrates.

Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples. In the following examples, parts and percentages are by weight unless otherwise specified.
(1) The weight average molecular weight (Mw) was measured by gel permeation chromatography in terms of standard polystyrene using cyclohexane at 40 ° C. as an eluent.
(2) The hydrogenation rate was determined by ¹ H-NMR measurement.
(3) The glass transition temperature (Tg) was measured by raising the temperature at 10 ° C./min using a differential scanning calorimeter.
(4) The light transmittance at 400 nm of the molded body was measured using an ultraviolet-visible spectrophotometer (V-550, manufactured by Jusco International).
(5) The amount of volatile components in the polymer was measured by gas chromatography.

[Production Example 1] (Production Example of Polymer Solution)
The inside of a reactor having an internal volume of 1.5 m ³ equipped with a stirrer and a jacket for heating and cooling was replaced with nitrogen gas, 200 kg of styrene as a monomer, 600 kg of cyclohexane as a solvent, and dibutyl ether as a polymerization accelerator. 4 kg was supplied into the reactor, and 0.50 kg of a 15 wt% n-hexane solution of n-butyllithium was added as a polymerization catalyst, and a polymerization reaction was carried out at 60 ° C. for 2 hours. Thereafter, 0.2 kg of isopropanol was added as a polymerization terminator to complete the polymerization step, and a styrene polymer was obtained. The conversion rate of the styrene monomer into the styrene polymer in this polymerization reaction was 100%.
The obtained styrene polymer solution was transferred to a pressurizable reactor, 20 kg of a nickel-diatomite-alumina supported catalyst (E22U: manufactured by JGC Chemical Co., Ltd.) was added as a hydrogenation catalyst, and the hydrogen pressure in the reactor was changed to 4. A hydrogenation reaction was performed at 5 MPa and a temperature of 160 ° C. for 6 hours to obtain a vinylcyclohexane polymer. Mw of the obtained vinylcyclohexane polymer was 132000, and the hydrogenation rate was 99.9%.

[Example 1]
(Concentration process)
After the hydrogenation catalyst in the vinylcyclohexane polymer solution obtained in Production Example 1 was separated and removed by filtration, pentaerythritol tetrakis [3- (3,5-di-tert-butyl) was used as an antioxidant in the reaction solution. -4-hydroxyphenyl) propionate] (Irganox 1010, manufactured by Ciba Specialty Chemicals, Inc., molecular weight 1178) (hereinafter referred to as “antioxidant (A)”) 0.25 kg, and Tris (2,4- Di-tert-butylphenyl) phosphite (Irgaphos 168, manufactured by Ciba Specialty Chemicals, Inc., molecular weight 647) (hereinafter referred to as “antioxidant (B)”) was added in an amount of 0.25 kg. The ratio (molar ratio) of the structure (A) / structure (B) of the antioxidant at this time was 68.7 / 31.3, and the ratio of the molecular weight of 700 or more in the antioxidant was 35.4 mol%. .
The reaction solution (concentration 25%) was heated to 220 ° C. and then introduced into a pressurizable cylindrical solution concentrator (inner diameter 550 mm, height 500 mm, manufactured by BUSS) at 40 kg per hour. As an operation at the time of introduction, the reaction solution is preliminarily concentrated by separating and removing a part of the solvent in the reaction solution by flash separation method by setting the pressure difference to 3000 kPa and the exhaust pressure to 300 kPa. It was. The separated and evaporated solvent was transferred from the exhaust port to a heat exchanger and then recovered by condensation. The polymer concentration of the obtained polymer solution was 85%.
(Drying process)
The reaction solution pre-concentrated by the above method was added to a solvent removal apparatus (BUSS) provided with a plate fin heat exchanger (width 270 mm, height 200 mm, depth 255 mm, heat transfer area 4.3 m ² ). From the outlet of the cylindrical concentrator, it is directly introduced by a gear pump through the inside of a double tube through which a heating medium of 270 ° C. is passed, and heated at 270 ° C. and an operating pressure of 1 kPa in the apparatus by heating under reduced pressure, The removal process of the volatile component was performed. The evaporated solvent (cyclohexane) was sucked with a vacuum pump from the exhaust port and condensed by a heat exchanger and recovered. The molten vinylcyclohexane polymer collected at the bottom of the apparatus was continuously led out of the apparatus by a gear pump, extruded into a strand, cooled and solidified, and formed into a pellet by a pelletizer. In the series of operations, the time from introduction of the concentrated solution into the apparatus to pelletization (residence time in the apparatus) was 4 hours.
Mw of the obtained pellet-shaped vinylcyclohexane polymer was 105,000.
Moreover, it was 3 ppm when the amount of the volatile component in the said polymer was measured by the gas chromatography.
(Molded body)
The obtained pellets were injected with an injection molding machine (α-100B, manufactured by FANAC) under conditions of a mold temperature of 132 ° C., a cylinder temperature of 260 ° C., a nozzle temperature of 265 ° C., a holding pressure of 700 kg / m ² , and an injection speed of 20 mm / sec. Injection molding was performed to obtain a molded plate for measuring light transmittance having a thickness of 3 mm, a length of 65 mm, and a width of 65 mm. The light transmittance at 400 nm of the molded product was 91%.

[Example 2]
In Example 1, as antioxidant, the usage-amount of antioxidant (A) and antioxidant (B) was each 0.25 kg to 0.5 kg (structure (A) of antioxidant at this time) / The ratio (molar ratio) of structure (B) is 68.7 / 31.3, and the ratio of molecular weight of 700 or more in the antioxidant is 35.4 mol%. A vinylcyclohexane polymer and a molded plate for light transmittance measurement were obtained.
The Mw of the vinylcyclohexane polymer was 112,000, the amount of volatile components was 3 ppm, and the light transmittance of the molded plate was 90%.

[Example 3]
In Example 1, as antioxidant, the usage-amount of antioxidant (A) and antioxidant (B) was 0.25 kg to 1.0 kg, respectively (structure of antioxidant at this time (A) / The ratio (molar ratio) of structure (B) is 68.7 / 31.3, and the ratio of molecular weight of 700 or more in the antioxidant is 35.4 mol%. A vinylcyclohexane polymer, a molded plate for measuring light transmittance, and a molded plate for bending strength were obtained.
The Mw of the vinylcyclohexane polymer was 122,000, the amount of volatile components was 3 ppm, and the light transmittance of the molded plate was 88%.

[Example 4]
In Example 1, as an antioxidant, instead of using 0.25 kg of the antioxidant (A), 1.4 kg is used, and instead of using 0.25 kg of the antioxidant (B), 0.6 kg. (The ratio (molar ratio) of the structure (A) / structure (B) of the antioxidant at this time was 83.7 / 16.3, and the ratio of the molecular weight of 700 or more in the antioxidant was 56.2 mol%. Except for the above, a pellet-like vinylcyclohexane polymer and a molded plate for measuring light transmittance were obtained in the same manner as in Example 1.
The Mw of the vinylcyclohexane polymer was 116,000, the volatile component concentration was 3 ppm, and the light transmittance of the molded plate was 91%.

[Example 5]
In Example 1, instead of 0.25 kg of the antioxidant (B) as the antioxidant, 6- [3- (3-t-butyl-4-hydroxy-5-methyl) propoxy] -2,4,8, 10-tetra-t-butyldibenz [d. f] [1.3.2] -Dioxaphosphepine (Sumilyzer GP, manufactured by Sumitomo Chemical Co., Ltd., molecular weight 675) (hereinafter, sometimes referred to as “antioxidant (C)”) was used in an amount of 0.25 kg ( The ratio (molar ratio) of the structure (A) / structure (B) of the antioxidant at this time is 83.3 / 16.7, and the ratio of the molecular weight of 700 or more in the antioxidant is 36.4 mol%) In the same manner as in Example 1, a pellet-like vinylcyclohexane polymer and a molded plate for measuring light transmittance were obtained.
The Mw of the vinylcyclohexane polymer was 118,000, the volatile component concentration was 3 ppm, and the light transmittance of the molded plate was 91%.

[Comparative Example 1]
In the concentration step of Example 1, as the antioxidant, the amount of the antioxidant (A) used was changed from 0.25 kg to 0.5 kg, and the antioxidant (B) was not used (the antioxidant at this time) Concentration was carried out in the same manner as in the concentration step of Example 1 except that the ratio (molar ratio) of structure (A) / structure (B) was 100/0, and the ratio of molecular weight of 700 or more in the antioxidant was 100 mol%. A solution was obtained.
Thereafter, in the drying step of Example 1, in the same manner as in Example 1 except that the time from introduction of the concentrated solution into the apparatus to pelletization (residence time in the apparatus) was changed from 4 hours to 1 hour, A pellet-like vinylcyclohexane polymer was obtained.
Further, a molded plate for measuring light transmittance was obtained in the same manner as in Example 1.
The Mw of the vinylcyclohexane polymer was 119,000, the volatile component concentration was 80 ppm, and the light transmittance of the molded plate was 91%.

[Comparative Example 2]
In Comparative Example 1, in the same manner as Comparative Example 1, except that the time from introduction of the concentrated solution in the drying process into pelletization until the pelletization (residence time in the apparatus) was changed from 1 hour to 4 hours, the pellet form A vinylcyclohexane polymer was obtained.
Further, a molded plate for measuring light transmittance was obtained in the same manner as in Example 1.
The Mw of the vinylcyclohexane polymer was 85,000, the volatile component concentration was 3 ppm, and the light transmittance of the molded plate was 91%.

[Comparative Example 3]
In Example 1, 1.0 kg of antioxidant (C) was used in place of the antioxidant (A) and the antioxidant (B) as the antioxidant (the structure of the antioxidant at this time ( A) / structure (B) ratio (molar ratio) is 50/50, and the ratio of molecular weight of 700 or more in the antioxidant is 0 mol%. Combined, a molded plate for measuring light transmittance was obtained.
The Mw of the vinylcyclohexane polymer was 98,000, the volatile component concentration was 3 ppm, and the light transmittance of the molded plate was 86%.

[Comparative Example 4]
In Example 1, the amount of the antioxidant (A) and the amount of the antioxidant (B) used as the antioxidant was 0.25 kg to 2.5 kg, respectively (the structure of the antioxidant (A) / Example 1 except that the ratio (molar ratio) of the structure (B) was 35.4 / 64.6, and the ratio of the molecular weight of 700 or more in the antioxidant was 35.4 mol%). In the same manner as above, a pellet-like vinylcyclohexane polymer was obtained.
Further, a molded plate for measuring light transmittance was obtained in the same manner as in Example 1.
The Mw of the vinylcyclohexane polymer was 125,000, the volatile component concentration was 3 ppm, and the light transmittance of the molded plate was 80%.

From the above, it can be seen that the vinyl alicyclic hydrocarbon polymers obtained by the methods of the present invention in Examples 1 to 5 are suppressed in molecular weight reduction, have very few volatile components, and are excellent in transparency.
On the other hand, Comparative Example 1 which uses an antioxidant containing no structure (B) and has a short residence time in the apparatus suppresses a decrease in the molecular weight of the vinyl alicyclic hydrocarbon polymer and is excellent in transparency. There are many ingredients.
Comparative Example 2 using an antioxidant containing no structure (B) and having a long residence time in the apparatus has a very small amount of volatile components of the vinyl alicyclic hydrocarbon polymer and is excellent in transparency, but has a decreased molecular weight. large.
In Comparative Example 3 in which the proportion of the molecular weight of the antioxidant of 700 or more is small and the residence time in the apparatus is long, the amount of the volatile component of the vinyl alicyclic hydrocarbon polymer is extremely small, but the transparency is excellent and the molecular weight reduction is large. .
In Comparative Example 4 in which the amount of antioxidant added is large and the residence time in the apparatus is long, a decrease in the molecular weight of the vinyl alicyclic hydrocarbon polymer is suppressed and the amount of volatile components is extremely small, but the transparency is poor.

Claims (2)

A reaction liquid containing a vinyl alicyclic hydrocarbon polymer obtained by polymerizing a monomer containing a vinyl compound and hydrogenating as necessary, to 100 parts by mass of the monomer containing the vinyl compound Then, 0.1 to 2 parts by mass of an antioxidant satisfying the following conditions (1) to (3) is added, and then heated to evaporate and remove volatile components to recover the polymer. A method for producing a hydrogen polymer.
(1) The antioxidant has a partial structure represented by the formula (1) and a partial structure represented by the formula (2).
(2) The partial structure represented by formula (1) / the partial structure (molar ratio) represented by formula (2) is 90/10 to 10/90.
(3) In all the antioxidants, the content ratio of the antioxidant having a molecular weight of 700 or more is 10 mol% or more.

(In the formula ^(1), R 1, ^{R 2} are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms.)

(In formula (2), X ^{1 to} X ² each represents a monovalent organic group, and X ¹ and X ² may be bonded to each other to form a ring structure.)
The recovered vinyl alicyclic hydrocarbon polymer has a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography, which is 100,000 or more, and is a vinyl alicyclic. The production method according to claim 1, wherein the content of volatile components in the hydrocarbon polymer is 10 ppm or less.