JP5833399B2 - Method for producing acrylic resin composition and acrylic resin composition - Google Patents

Description

  The present invention relates to a method for producing an acrylic resin composition and an acrylic resin composition. Specifically, by adjusting the amount of acidic or basic substance used to neutralize the catalyst to an amount that does not allow the metal salt particles of the catalyst to grow, the pressure loss when filtering with a polymer filter is increased. The present invention relates to a novel method for producing an acrylic resin composition and an acrylic resin composition that can be significantly suppressed.

  An acrylic resin having a ring structure in the main chain is known as an acrylic resin having both transparency and heat resistance. Since the acrylic resin has a higher glass transition temperature (Tg) than an acrylic resin having no ring structure in the main chain, a high molding temperature is required.

  On the other hand, when an acrylic resin is exposed to light containing ultraviolet rays, it may turn yellow and the transparency may be lowered. As a method for preventing this, a method of adding an ultraviolet absorber is known. Therefore, it is preferable to add an ultraviolet absorber also to an acrylic resin having a ring structure in the main chain. However, since the acrylic resin has a high molding temperature as described above, the addition of the ultraviolet absorber causes foaming or bleeding out. There was a problem that it was easy.

  In order to solve this problem, a thermoplastic resin composition containing a thermoplastic acrylic resin and an ultraviolet absorber having a molecular weight of 700 or more and having a Tg of 110 ° C. or more has been proposed (Patent Document 1).

  In Patent Document 1, the resin composition obtained an acrylic polymer having a ring structure in the main chain by performing a cyclization condensation reaction of the polymer using a cyclization catalyst (2-ethylhexyl phosphate). Then, it is manufactured by the method including the process of neutralizing the said cyclization catalyst using the basic substance (zinc octylate) which is 1 molar equivalent with respect to the usage-amount of the said cyclization catalyst.

  Patent Document 1 describes that the resin composition may be filtered through a polymer filter in order to remove foreign substances present in the resin composition and improve the appearance of the film.

  As another method for neutralizing the cyclization catalyst used in the production of the acrylic polymer having a ring structure in the main chain, the cyclization catalyst that is an organic acid is neutralized with a metal salt of a typical metal element. A method is disclosed (Patent Document 2).

JP 2009-052021 A (published March 12, 2009) JP 2007-262396 A (published March 12, 2007)

  However, when the present inventors produce a thermoplastic resin composition by the method described in Patent Document 1 using a basic substance that is 1 molar equivalent relative to the amount of the cyclization catalyst used, there is a problem in short-time production. However, it was found that particulate foreign matters increase in the resin composition when production is carried out continuously for a long time. It was speculated that this was due to the fact that the ultraviolet absorber promoted the crystal growth of the salt produced by the reaction between the cyclization catalyst and the basic substance.

  And this inventor discovered for the first time that as a result of the said particulate foreign material clogging a polymer filter, pressure loss became large and the time which can be continuously produced became short.

  The present inventor has also found that the crystal growth of the salt does not occur when the resin composition does not contain an ultraviolet absorber, and in that case, the pressure loss in the polymer filter does not increase. On the other hand, Patent Document 2 does not disclose a resin composition containing an ultraviolet absorber in the first place and does not mention the use of a polymer filter. Therefore, the method described in Patent Document 2 cannot solve the above problem.

  As described above, when the present inventor manufactures a thermoplastic acrylic resin containing an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber according to a conventionally known method, continuous production for a long time can be achieved. The main object is to find an acrylic resin composition containing an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber. While maintaining the above characteristics, the crystal growth of the salt caused by the reaction between the catalyst and the basic substance or acidic substance (hereinafter also referred to as “neutralization reaction”) is prevented, and the acrylic resin composition is produced continuously for a long time. It is to provide a method that makes it possible.

  In order to solve the above problems, a method for producing an acrylic resin composition according to the present invention is a method for producing an acrylic resin composition containing an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber. In addition, by using an acidic substance or a basic substance as a catalyst, a cyclization condensation reaction of an acrylic polymer is performed to form a ring structure in the main chain of the polymer, and an acrylic having a ring structure in the main chain. A cyclization step for obtaining a polymer, and when an acidic substance is used as the catalyst, the catalyst is neutralized with a basic substance. When a basic substance is used as the catalyst, the catalyst is neutralized with an acidic substance. The amount of the basic substance or acidic substance used in the neutralization step is 0.1 to 0.7 molar equivalents relative to the amount of catalyst used.

  According to the above configuration, since the amount of the basic substance or acidic substance used for the catalyst is optimized, the effect of the basic substance or acidic substance neutralizing the catalyst is maintained, and the acrylic resin composition In addition to maintaining the heat resistance, it is possible to prevent the growth of salt crystals caused by the neutralization reaction and to suppress the formation of particulate foreign matters.

  Therefore, when filtering the obtained acrylic resin composition, since the pressure loss in a polymer filter can be suppressed, the said acrylic resin composition can be continuously produced for a long time.

  In the manufacturing method of the acrylic resin composition concerning this invention, it is preferable that the molecular weight of the said ultraviolet absorber is 600 or more.

  According to the said structure, generation | occurrence | production of foaming, bleed-out, etc. is suppressed also at the time of shaping | molding at high temperature, and generation | occurrence | production of the problem by evaporation of a ultraviolet absorber can be reduced. And since the usage-amount with respect to the said catalyst of the said basic substance or acidic substance used for the said neutralization process is optimized, the said acrylic resin composition can be continuously produced more stably for a long time.

  In the method for producing an acrylic resin composition according to the present invention, the ultraviolet absorber is preferably a compound having a hydroxyphenyltriazine skeleton.

  The compound is less likely to bleed out and has good compatibility with the acrylic polymer having a ring structure in the main chain. Therefore, the acrylic resin composition can be continuously produced more stably for a long time.

  In the method for producing an acrylic resin composition according to the present invention, the acrylic resin composition preferably contains 50% by weight or more and less than 100% by weight of an acrylic polymer having a ring structure in the main chain.

  According to the above configuration, the acrylic resin composition is characterized by the acrylic polymer having a ring structure in the main chain, wherein the content of the acrylic polymer having a ring structure in the main chain has both transparency and heat resistance. It is a content that can be sufficiently imparted to objects. Therefore, it is possible to provide the acrylic resin composition having desired characteristics such as mechanical strength and molding processability in addition to excellent transparency and heat resistance.

  In the method for producing an acrylic resin composition according to the present invention, the acrylic resin composition preferably contains 0.01% by weight or more and 5% by weight or less of the ultraviolet absorber.

  According to the said structure, since the said acrylic resin composition contains a suitable amount of ultraviolet absorbers, the yellowing can be prevented and the said acrylic resin composition by which transparency was maintained can be provided.

  In the method for producing an acrylic resin composition according to the present invention, the acrylic resin composition has a yellowness (YI) measured by ASTM E313 of 15% chloroform solution of the acrylic resin composition of 0 or more and 15 or less. preferable.

  As described above, the above-described method maintains the effects of neutralization of the catalyst (maintaining heat resistance, preventing foaming caused by the cyclization catalyst), and crystal growth of salts caused by the UV absorber in the neutralization reaction. Can be prevented.

  Thus, the ultraviolet absorber contained in the acrylic resin composition is not used for crystal growth of the salt. Therefore, as a result that the ultraviolet absorber can sufficiently fulfill its original role of preventing yellowing (decrease in transparency), the resulting yellowness of the acrylic resin composition is suppressed to a low level as in the above configuration. Conceivable. Therefore, according to the said structure, an optical film etc. with high transparency can be provided.

  In the manufacturing method of the acrylic resin composition concerning this invention, it is preferable to have a filtration process which filters the acrylic resin composition which passed through the said neutralization process using a polymer filter.

  According to the above method, since the crystal growth of the salt in the neutralization reaction is remarkably suppressed, the appearance defects are extremely reduced by filtering the acrylic resin composition that has undergone the neutralization step using a polymer filter. A small amount of acrylic resin composition can be produced stably and continuously for a long time.

  An acrylic resin composition according to the present invention is a thermoplastic acrylic acid resin composition containing an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber, and is 15% chloroform of the acrylic resin composition. The solution is characterized in that the yellowness (YI) measured by ASTM E313 is 0 or more and 15 or less.

  According to the said structure, it has characteristics, such as high heat resistance based on the acrylic polymer which has a ring structure in a principal chain, mechanical strength, and moldability, and can have very low yellowness. Therefore, it is possible to provide a material extremely useful as a material for an optical film or the like.

  The present invention relates to a method for producing an acrylic resin composition containing an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber, and using an acidic substance or a basic substance as a catalyst, A cyclization step of polymer is performed to form an acrylic polymer having a ring structure in the main chain by forming a ring structure in the main chain of the polymer, and an acidic substance is used as the catalyst Neutralizing the catalyst with a basic substance, and neutralizing the catalyst with an acidic substance when a basic substance is used as the catalyst, the basic substance used in the neutralization step or The usage-amount of an acidic substance is a structure that it is 0.1-0.7 molar equivalent with respect to the usage-amount of the said catalyst.

  Therefore, when the obtained acrylic resin composition is filtered, pressure loss in the polymer filter can be suppressed, so that the acrylic resin composition can be produced continuously for a long time.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, in the present specification, the description “A to B” means A or more and B or less.

[1. Method for producing acrylic resin composition]
(A. Structure of acrylic polymer having a ring structure in the main chain)
A method for producing an acrylic resin composition according to the present invention is a method for producing an acrylic resin composition comprising an acrylic polymer having a ring structure in the main chain and an ultraviolet absorber, wherein an acidic substance or a base is used as a catalyst. A cyclization step of obtaining an acrylic polymer having a cyclic structure in the main chain by performing a cyclization condensation reaction of the acrylic polymer by forming a cyclic structure in the main chain of the polymer, Neutralizing the catalyst with a basic substance when an acidic substance is used as the catalyst, and neutralizing the catalyst with an acidic substance when using a basic substance as the catalyst. The usage-amount of the said basic substance or acidic substance used for a summation process is 0.1-0.7 molar equivalent with respect to the usage-amount of the said catalyst.

  Moreover, the said manufacturing method is a polymerization process for obtaining the said acrylic polymer, the devolatilization process which volatilizes the alcohol byproduced in a cyclization process, and the resin composition obtained by a neutralization process is filtered with a polymer filter. It may include a filtration step.

  In this specification, the “acrylic polymer” refers to a polymer having a structural unit derived from a (meth) acrylate monomer (hereinafter referred to as “(meth) acrylate unit”) in the main chain. The “acrylic polymer having a ring structure in the main chain” refers to a polymer containing a (meth) acrylate unit and a ring structure in the main chain.

  The ring structure means a dealcoholization cyclocondensation reaction (hereinafter also referred to as a cyclization reaction) between a hydroxyl group or a carboxyl group in the molecular chain of the (meth) acrylate unit and an ester group in the molecular chain. ). Examples of the ring structure include a lactone ring structure, a glutaric anhydride structure, a glutarimide structure, an N-substituted maleimide structure, and a maleic anhydride structure.

  The total content of the (meth) acrylic acid ester unit and the content of the ring structure in the “acrylic polymer having a ring structure in the main chain” is preferably 50% by weight or more, more preferably in the main chain. Is 70% by weight or more, more preferably 90% by weight, particularly preferably 95% by weight or more, and most preferably 99% by weight or more.

  The content of the ring structure (excluding the lactone ring structure) in the “acrylic polymer having a ring structure in the main chain” is not particularly limited, but is, for example, 5 to 90% by weight, and 10 to 70% by weight. Is preferable, 10 to 60% by weight is more preferable, and 10 to 50% by weight is further preferable.

  When the “acrylic polymer having a ring structure in the main chain” has a lactone ring structure in the main chain, the content of the lactone ring structure in the polymer is not particularly limited, but is, for example, 5 to 90% by weight, Hereinafter, 20 to 90% by weight, 30 to 90% by weight, 35 to 90% by weight, 40 to 80% by weight, and 45 to 75% by weight are more preferable.

  When the content of the ring structure in the “acrylic polymer having a ring structure in the main chain” becomes excessively small, the heat resistance of the resin composition and the resin molded product obtained by molding the composition may be reduced, Solvent resistance and surface hardness may be insufficient. On the other hand, when the said content rate becomes large too much, the moldability and handling property of a resin composition may fall.

(Meth) acrylic acid ester units are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate t-butyl (meth) acrylate N-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, (meth) acrylic acid Dicyclopentanyl, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (
It is a structural unit derived from monomers such as (meth) acrylic acid 2,3,4,5,6-pentahydroxyhexyl and (meth) acrylic acid 2,3,4,5-tetrahydroxypentyl.

  The “acrylic polymer having a ring structure in the main chain” may contain two or more types of (meth) acrylic acid ester units. The “acrylic polymer having a ring structure in the main chain” preferably contains methyl (meth) acrylate as a (meth) acrylic acid ester unit. By containing methyl (meth) acrylate, the thermal stability of the acrylic resin composition obtained by the production method according to the present invention and the resin molded product obtained by molding the composition can be improved.

  The “acrylic polymer having a ring structure in the main chain” may also contain structural units other than (meth) acrylic acid ester units. Examples of the structural unit include a structural unit derived from a monomer containing a hydroxyl group, a structural unit derived from a monomer containing a carboxylic acid group, and the like. In the production method according to the present invention, since the cyclic structure is introduced into the main chain by a cyclization reaction, the above monomer is copolymerized when the above “acrylic polymer having a ring structure in the main chain” is polymerized. It is preferable.

  Examples of the monomer containing a hydroxyl group include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and methyl 2- (hydroxyethyl) acrylate.

  Examples of the monomer containing a carboxylic acid group include monomers such as acrylic acid, methacrylic acid, crotonic acid, 2- (hydroxymethyl) acrylic acid, and 2- (hydroxyethyl) acrylic acid. .

  Two or more of these monomers may be copolymerized in the “acrylic polymer having a ring structure in the main chain”. A monomer containing a hydroxyl group and a monomer containing a carboxylic acid group change into a ring structure by a cyclization reaction, but the above “acrylic polymer having a ring structure in the main chain” includes a hydroxyl group. A structural unit derived from an unreacted monomer and / or a structural unit derived from an unreacted monomer containing a carboxylic acid group may be contained.

  The “acrylic polymer having a ring structure in the main chain” may contain other structural units. Examples of the other structural units include styrene, vinyl toluene, α-methyl styrene, α-hydroxymethyl styrene, α-hydroxyethyl styrene, acrylonitrile, methacrylonitrile, methallyl alcohol, allyl alcohol, ethylene, propylene, 4 Examples include structural units derived from monomers such as -methyl-1-pentene, vinyl acetate, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, and N-vinyl carbazole. The “acrylic polymer having a ring structure in the main chain” may contain two or more kinds of the other structural units.

  The type of the “ring structure” is not particularly limited. For example, at least one selected from a lactone ring structure, a glutaric anhydride structure, a glutarimide structure, an N-substituted maleimide structure, and a maleic anhydride structure can be used.

  Since the Tg of the acrylic resin composition produced by the “acrylic polymer having a ring structure in the main chain” and the production method according to the present invention can be further improved, the ring structure has a glutarimide structure, anhydrous It is preferably at least one selected from a glutaric acid structure and a lactone ring structure.

  The following formula (1) shows a glutarimide structure and a glutaric anhydride structure.

In the above formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group, and X ¹ is an oxygen atom or a nitrogen atom. When X ¹ is an oxygen atom, R ³ does not exist, and when X ¹ is a nitrogen atom, R ³ is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, or a phenyl group. .

When X ¹ is a nitrogen atom, the ring structure represented by the formula (1) is a glutarimide structure.
The glutarimide structure can be formed, for example, by imidizing a (meth) acrylic acid ester polymer with an imidizing agent such as methylamine.

When X ¹ is an oxygen atom, the ring structure represented by the formula (1) is a glutaric anhydride structure.
The glutaric anhydride structure can be formed, for example, by subjecting a copolymer of (meth) acrylic ester and (meth) acrylic acid to dealcoholization cyclocondensation within the molecule.

  The following formula (2) shows an N-substituted maleimide structure and a maleic anhydride structure.

In the above formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, and X ² is an oxygen atom or a nitrogen atom. When X ² is an oxygen atom, R ⁶ does not exist, and when X ² is a nitrogen atom, R ⁶ is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, or a phenyl group. .

When X ² is a nitrogen atom, the ring structure represented by the formula (2) is an N-substituted maleimide structure. The acrylic resin having an N-substituted maleimide structure in the main chain can be formed, for example, by copolymerizing an N-substituted maleimide and a (meth) acrylic ester.

When X ² is an oxygen atom, the ring structure represented by the formula (2) is a maleic anhydride structure.
An acrylic resin having a maleic anhydride structure in the main chain is, for example, maleic anhydride and (meth)
It can be formed by copolymerization with an acrylate ester.

In each method for forming a ring structure exemplified in the description of formulas (1) and (2), all the polymers used for forming each ring structure have (meth) acrylate units as constituent units. The resin obtained by this method is an acrylic resin.

  The ring structure is more preferably a lactone ring structure, because it does not contain a nitrogen atom in the ring structure, and is less likely to be colored (yellowing) and has excellent optical properties when formed into a resin molded product. That is, the “acrylic polymer having a ring structure in the main chain” is more preferably an acrylic polymer having a lactone ring structure in the main chain.

  The lactone ring structure that the “acrylic polymer having a ring structure in the main chain” may have in the main chain is not particularly limited, and may be, for example, a 4- to 8-membered ring. Since it is excellent in stability, a 5-membered ring or a 6-membered ring is preferable, and a 6-membered ring is more preferable.

  A lactone ring structure that is a 6-membered ring is, for example,

In the above formula (3), R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.

  The organic residue in the above formula (3) is, for example, an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group or a propyl group; a carbon number such as an ethenyl group or a propenyl group is 1 to 20 carbon atoms. An unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group having 1 to 20 carbon atoms, such as a phenyl group and a naphthyl group; the alkyl group, the unsaturated aliphatic hydrocarbon group, and the aromatic hydrocarbon group In which at least one hydrogen atom is substituted with at least one group selected from a hydroxyl group, a carboxyl group, an ether group and an ester group.

  The “acrylic polymer having a ring structure in the main chain” may have a structural unit other than the (meth) acrylic acid ester unit and the (meth) acrylic acid unit. Such structural units include, for example, styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, vinyl acetate, methallyl alcohol, allyl alcohol, 2-hydroxymethyl-1-butene, α- 2- (hydroxyalkyl) acrylic acid ester such as hydroxymethylstyrene, α-hydroxyethylstyrene, methyl 2- (hydroxyethyl) acrylate, 2- (hydroxyalkyl) acrylic acid such as 2- (hydroxyethyl) acrylic acid, A structural unit derived from a monomer such as The “acrylic polymer having a ring structure in the main chain” may have two or more of these structural units.

  The “acrylic polymer having a ring structure in the main chain” may have a structural unit (UVA unit) having an ultraviolet absorbing ability. In this case, the ultraviolet absorbing ability of the resin composition and the resin molded product obtained by molding the composition is further improved. Further, depending on the structure of the UVA unit, compatibility between the “acrylic polymer having a ring structure in the main chain” and the ultraviolet absorber is improved.

  The monomer that is the source of the UVA unit is not particularly limited, and examples thereof include a benzotriazole derivative, a triazine derivative, or a benzophenone derivative into which a polymerizable group is introduced. The polymerizable group to be introduced can be appropriately selected according to the structural unit of the “acrylic polymer having a ring structure in the main chain”.

  Specific examples of the monomer include 2- (2′-hydroxy-5′-methacryloyloxy) ethylphenyl-2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd., trade name RUVA-93), 2- (2′-hydroxy- 5'-methacryloyloxy) phenyl-2H-benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methacryloyloxy) phenyl-2H-benzotriazole.

  Other specific examples of the monomer include triazine derivatives represented by the following formulas (4), (5), and (6), or benzotriazole derivatives represented by the following formula (7). .

  As the monomer, 2- (2'-hydroxy-5'-methacryloyloxy) ethylphenyl-2H-benzotriazole is preferable because of its high ultraviolet absorption ability. According to the UVA unit having a high ultraviolet absorbing ability, a desired ultraviolet absorbing effect can be obtained even when the content of the UVA unit in the “acrylic polymer having a ring structure in the main chain” is low.

  That is, even when the “acrylic polymer having a ring structure in the main chain” includes UVA units, the content of constituent units other than UVA units can be relatively increased, and is suitable for various uses such as optical members. It becomes easy to obtain a resin composition having various characteristics (for example, thermoplasticity and heat resistance).

  Further, since the coloration of the resin composition tends to occur when the content of the UVA unit is increased, the UVA unit having a high ultraviolet absorption ability can suppress the coloring of the resin molded product finally obtained, The molded article is suitable for use as an optical member.

  When the “acrylic polymer having a ring structure in the main chain” includes a UVA unit, the content of the unit in the “acrylic polymer having a ring structure in the main chain” is preferably 20% by weight or less, More preferably, it is less than wt%. When the said content rate exceeds 20 weight%, the heat resistance as a resin composition will fall.

  The weight average molecular weight of the “acrylic polymer having a ring structure in the main chain” is, for example, in the range of 1,000 to 300,000, preferably in the range of 5,000 to 250,000, and 10,000 to 200. , More preferably in the range of 50,000 to 200,000.

  The “acrylic polymer having a ring structure in the main chain” is a cyclic condensation reaction of an acrylic polymer by using an acidic substance or a basic substance as a catalyst, and the main chain of the polymer has a ring structure. To obtain an acrylic polymer having a ring structure in the main chain.

  The “acrylic polymer having a ring structure in the main chain” is a cyclic condensation reaction of an acrylic polymer by using an acidic substance or a basic substance as a catalyst, and the main chain of the polymer has a ring structure. Can be obtained by a step of forming (cyclization step).

  The acrylic polymer can form a lactone ring structure by a cyclocondensation reaction between a hydroxyl group and an ester group in the molecular chain.

  Hereinafter, the acrylic polymer as a raw material for forming the lactone ring structure will be described. The acrylic polymer is preferably a vinyl monomer polymer represented by the following formula (8).

In the formula (8), R ¹⁰ and R ¹¹ are each independently a hydrogen atom or a group exemplified as an organic residue in the formula (3).

Specific examples of the monomer represented by the formula (8) include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, 2- (hydroxy Methyl) normal butyl acrylate, 2- (hydroxymethyl) acrylate t-butyl and the like.

  Among these, methyl 2- (hydroxymethyl) acrylate and ethyl 2- (hydroxymethyl) acrylate are preferable, and since the effect of improving heat resistance due to formation of a lactone ring is high, methyl 2- (hydroxymethyl) acrylate ( MHMA) is particularly preferred. The acrylic polymer may be a polymer obtained by copolymerizing two or more of these monomers.

  The acrylic polymer may be a copolymer of a monomer represented by the above formula (8) and a monomer having an ester group (excluding a monomer represented by the formula (8)). Good.

  Examples of the monomer having an ester group include (meth) acrylic acid esters. The (meth) acrylic acid ester is a monomer other than the monomer represented by the formula (8), for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid acrylic esters such as t-butyl, cyclohexyl acrylate, benzyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, methacrylic acid And methacrylates such as benzyl acid;

  Among these, methyl methacrylate (MMA) is particularly preferable because a resin having excellent heat resistance and transparency can be obtained by the cyclization condensation reaction.

  When the acrylic polymer is a copolymer of the monomer represented by the formula (8) and the monomer having an ester group, a monomer group for obtaining the acrylic polymer The preferred range of the content of each monomer in is as follows.

  That is, about the content rate of the monomer shown by said Formula (8), the range of 5-90 weight% is preferable, The range of 10-70 weight% is more preferable, The range of 10-60 weight%, More preferably in the order of 50% by weight.

When the content is less than 5% by weight, the amount of lactone ring formed when the acrylic polymer is subjected to cyclization condensation reaction is reduced, and the resulting resin has heat resistance, solvent resistance, surface Hardness may be insufficient.

  On the other hand, when the said content rate exceeds 90 weight%, when carrying out the cyclization condensation reaction of the said acrylic polymer, a gel will arise and transparency and moldability of the obtained resin may fall.

  The acrylic polymer includes the above-exemplified monomers and other monomers, for example, various monomers including a hydroxyl group, unsaturated carboxylic acid, a monomer represented by the following formula (9), and the like. , And a copolymer.

In the above formula (9), R ¹² is a hydrogen atom or a methyl group, and X is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, —CO—R. ¹³ groups or —C—O—R ¹⁴ groups, where Ac is an acetyl group, R ¹³ and R ¹⁴ are groups exemplified as a hydrogen atom or an organic residue in formula (3).

Here, as various monomers containing a hydroxyl group, monomers other than the monomer represented by the formula (8), for example, α-hydroxymethylstyrene, α-hydroxyethylstyrene, 2- ( 2- (hydroxyalkyl) acrylic esters such as hydroxyethyl) methyl acrylate; 2- (hydroxyalkyl) such as 2- (hydroxyethyl) acrylic acid
Acrylic acid; and the like.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. Among these, acrylic acid and methacrylic acid are particularly preferable.

Examples of the monomer represented by the formula (9) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, and vinyl acetate. Among these, styrene and α-methylstyrene are particularly preferable for exerting the effects of the present invention. These monomers may be used alone or in combination of two or more.

  When the acrylic polymer is a copolymer of the monomer exemplified above and the other monomer, the other single monomer in the monomer group for obtaining the acrylic polymer. The total content of the body is preferably 0 to 30% by weight, more preferably 0 to 20% by weight, and further preferably 0 to 15% by weight and 0 to 10% by weight in this order.

  The acrylic polymer may be a copolymer of the above-exemplified monomers including the other monomers and the UVA monomer described above. By carrying out the cyclization condensation reaction of such an acrylic polymer, an acrylic resin further having ultraviolet absorbing ability can be obtained.

  The acrylic polymer can form a glutaric anhydride structure by a cyclization condensation reaction between a carboxyl group and an ester group in the molecular chain. Examples of the acrylic polymer that forms a glutaric anhydride structure include a copolymer of (meth) acrylic acid ester and (meth) acrylic acid.

  As the (meth) acrylic acid ester, the above-mentioned methyl methacrylate (MMA) or the like can be used. As (meth) acrylic acid, for example, acrylic acid or methacrylic acid can be used.

  The acrylic polymer that forms the glutaric anhydride structure has a structural unit derived from the monomer used to form the polymer. The content rate of each structural unit in the said acrylic polymer is determined according to content of each monomer contained in the monomer group superposed | polymerized in order to obtain the said acrylic polymer.

  As a polymerization method for obtaining the acrylic polymer, a conventionally known method, for example, a method described in Patent Document 2 can be used. In this specification, the process of performing polymerization for obtaining an acrylic polymer is also referred to as “polymerization process”. As a polymerization method, it is preferable to obtain the acrylic polymer by solution polymerization since an acrylic polymer can be obtained and then a cyclic condensation reaction of the acrylic polymer can be performed. Moreover, in order to perform reaction efficiently, it is preferable to superpose | polymerize in nitrogen atmosphere.

  The polymerization temperature and the polymerization time vary depending on the type and ratio of the monomer used, but the polymerization temperature is preferably 0 to 150 ° C., more preferably 80 to 140 ° C., and the polymerization time Is preferably 0.5 to 20 hours, more preferably 1 to 10 hours.

  When the acrylic polymer is formed by solution polymerization, examples of the polymerization solvent used include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; chloroform, dimethyl sulfoxide ( DMSO), tetrahydrofuran and the like. Among them, it is preferable to use aromatic hydrocarbons and ketones as the polymerization solvent, and it is particularly preferable to use toluene and methyl isobutyl ketone.

  When the acrylic polymer is polymerized, a polymerization initiator may be added as necessary. The polymerization initiator is not particularly limited, and examples thereof include cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, and t-amyl peroxide. Organic peroxides such as oxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2-methyl) And azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile);

  These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers or the polymerization conditions.

  When the acrylic polymer is formed by solution polymerization, the polymerization product contains the polymerization solvent used for the polymerization in addition to the acrylic polymer, but the acrylic polymer is not necessarily removed by removing the solvent. May not be taken out as a solid.

  As described above, the polymerization product can be introduced into the subsequent cyclization step while still containing the solvent. Of course, after the acrylic polymer is taken out as a solid, a solvent suitable for carrying out the cyclization step may be added to the cyclization step more than the solvent used during the polymerization.

  Solvents suitable for carrying out the cyclization step are not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; chloroform, DMSO, tetrahydrofuran, and the like. Although it can be used, it is preferably the same type of solvent as that used in the polymerization step.

  The acrylic polymer is not necessarily prepared by a polymerization reaction, and a commercially available product may be used.

(B. Cyclization step)
The cyclization step in the production method according to the present invention means that an acidic substance or a basic substance is used as a catalyst to carry out a cyclization condensation reaction of an acrylic polymer to form a ring structure in the main chain of the polymer. In this step, an acrylic polymer having a ring structure in the main chain is obtained. In this specification, the catalyst used for the cyclization condensation reaction of an acrylic polymer is also called a cyclization catalyst.

  By forming a ring structure in the main chain by the cyclization condensation reaction, a resin having excellent heat resistance can be obtained. In addition, by adding a cyclization catalyst to the acrylic polymer, side reactions between the monomer and the catalyst, branching and crosslinking during the polymerization are suppressed, and excellent thermal stability and mechanical strength of the acrylic polymer. Can be granted.

  As the catalyst, an acidic substance or a basic substance can be used. The acidic substance may be an inorganic substance or an organic substance as long as it can function as a catalyst for the cyclization condensation reaction.

  For example, sulfuric acid or hydrochloric acid can be used as the inorganic substance. The said inorganic substance may be used independently and may be used in mixture of 2 or more types.

  Examples of the acidic substance that is an organic substance include an organic phosphorus compound, an esterification catalyst or a transesterification catalyst such as p-toluenesulfonic acid generally used as a catalyst for cyclization condensation reaction, acetic acid, propionic acid, benzoic acid, acrylic acid And organic carboxylic acids such as methacrylic acid.

  Among these, it is preferable to use an organic phosphorus compound as the organic substance. This is because by using an organic phosphorus compound as a cyclization catalyst, the cyclization condensation reaction rate can be improved, and the coloring of the acrylic polymer having a lactone ring obtained can be greatly reduced. Furthermore, by using an organophosphorus compound as a cyclization catalyst, it is possible to suppress a decrease in molecular weight that can occur in the case of using a devolatilization step described later, and there is an advantage that excellent mechanical strength can be imparted. Because.

  Examples of the organic phosphorus compound that can be used in the present invention include alkyl (aryl) phosphonous acids such as methyl phosphonous acid, ethyl phosphonous acid, and phenyl phosphonous acid (however, these are alkyls that are tautomers) (Which may be (aryl) phosphinic acid) and monoesters or diesters thereof; dialkyl (aryl) phosphinic acids such as dimethylphosphinic acid, diethylphosphinic acid, diphenylphosphinic acid, phenylmethylphosphinic acid, phenylethylphosphinic acid and These esters; alkyl (aryl) phosphonic acids such as methylphosphonic acid, ethylphosphonic acid, trifluoromethylphosphonic acid, phenylphosphonic acid and their monoesters or diesters; methylphosphinic acid, Alkyl (aryl) phosphinic acids such as phosphinic acid and phenylphosphinic acid and esters thereof; methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, diphenyl phosphite Phosphorous acid monoester, diester or triester such as trimethyl phosphite, triethyl phosphite, triphenyl phosphite; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate Lauryl phosphate, stearyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diphosphate Isostearyl, diphenyl phosphate, trimethyl phosphate, lithium Phosphoric acid monoesters, diesters or triesters such as triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; methylphosphine, ethylphosphine, phenylphosphine, dimethylphosphine, Mono-, di- or tri-alkyl (aryl) phosphine such as diethylphosphine, diphenylphosphine, trimethylphosphine, triethylphosphine, triphenylphosphine; methyldichlorophosphine, ethyldichlorophosphine, phenyldichlorophosphine, dimethylchlorophosphine, diethylchlorophosphine Alkyl (aryl) halogen phosphines such as diphenylchlorophosphine; Mono-, di- or tri-alkyl (aryl) phosphine oxides such as fin, phenyl phosphine oxide, dimethyl phosphine oxide, diethyl phosphine oxide, diphenyl phosphine oxide, trimethyl phosphine oxide, triethyl phosphine oxide, triphenyl phosphine oxide; tetramethyl chloride And halogenated tetraalkyl (aryl) phosphonium such as phosphonium, tetraethylphosphonium chloride and tetraphenylphosphonium chloride.

  These organic phosphorus compounds may be used alone or in combination of two or more. Among these organophosphorus compounds, since the catalytic activity is high and the colorability is low, alkyl (aryl) phosphonous acid, phosphorous acid monoester or diester, phosphoric acid monoester or diester, and alkyl (aryl) phosphonic acid Preferably, alkyl (aryl) phosphonous acid, phosphorous acid monoester or diester, phosphoric acid monoester or diester is more preferable, and alkyl (aryl) phosphonous acid, phosphoric acid monoester or diester is particularly preferable.

  As described above, the acidic substance may be an organic substance or an inorganic substance. From the viewpoint of operability that it can be dissolved or dispersed in an organic solvent, and from the viewpoint of suppressing coloring of the reaction product, the organic substance Is preferably used.

  As described above, it is possible to use a basic substance as a cyclization catalyst. The basic substance is not particularly limited as long as it can function as a catalyst for the cyclization condensation reaction. For example, metal carboxylates, metal complexes, metal oxides and the like can be mentioned, metal carboxylates and metal oxides are preferable, and metal carboxylates are particularly preferable.

  The metal is not particularly limited as long as it does not inhibit the physical properties of the resin composition and does not cause environmental pollution at the time of disposal. For example, alkali metals such as lithium, sodium, and potassium; magnesium, calcium Alkaline earth metals such as strontium and barium; zinc; zirconium; and the like.

  The carboxylic acid constituting the metal carboxylate is not particularly limited. For example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, Lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, tridecanoic acid, pentadecanoic acid, heptadecanoic acid, lactic acid, malic acid, citric acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, adipic acid, etc. Is mentioned.

  The organic component in the metal complex is not particularly limited, and examples thereof include acetylacetone. Examples of the metal oxide include zinc oxide, calcium oxide, magnesium oxide and the like, and zinc oxide is preferable.

  Moreover, the compound of the group 12 element described in Unexamined-Japanese-Patent No. 2009-144112 (published July 2, 2009) can also be used suitably as a basic substance. Of these, zinc compounds are preferably used because they have a large effect of promoting the cyclization reaction.

  Specific types of the zinc compound are not particularly limited, and examples thereof include organic zinc compounds such as zinc acetate, zinc propionate, and zinc octylate; inorganic zinc compounds such as zinc oxide, zinc chloride, and zinc sulfate; trifluoromethanesulfonic acid An organic zinc compound containing fluorine such as zinc can be suitably used.

  The amount of the cyclization catalyst used in the cyclization condensation reaction is not particularly limited, but is preferably 0.001 to 5% by weight, for example, with respect to the acrylic polymer having a ring structure in the main chain. More preferably, it is 0.01 to 2.5 weight%, More preferably, it is 0.01 to 1 weight%, Especially preferably, it is 0.05 to 0.5 weight%.

  When the amount of the catalyst used is less than 0.001% by weight, the reaction rate of the cyclization condensation reaction may not be sufficiently improved. On the other hand, when the amount of the catalyst used exceeds 5% by weight, the obtained resin may be colored, or the resin may be cross-linked, making melt molding difficult.

  The addition timing of the catalyst is not particularly limited. For example, the catalyst may be added during the polymerization process, may be added after the polymerization process, or may be added in both of them. The catalyst may be added while heating during the polymerization or after the polymerization, or may be heat-treated at a high temperature after the addition of the cyclization catalyst.

  The method for heating in the cyclization condensation reaction is not particularly limited, and a conventionally known method may be used. For example, the polymerization solution containing the polymerization solvent obtained by the polymerization step may be heat-treated as it is, or the solvent may be heat-treated after devolatilization. In one preferred embodiment, the cyclization reaction is carried out at a temperature of 200 ° C. or higher in a pressure-resistant device such as an autoclave in a solution state to promote the cyclization reaction at a high temperature.

  Or a devolatilization process can also be performed using the heating furnace or reaction apparatus provided with the vacuum apparatus or devolatilization apparatus for removing a volatile component, the extruder provided with the devolatilization apparatus, etc. In the present invention, it is one of preferred embodiments to heat the polymerization solution containing the catalyst under pressure.

  After heating in a state containing a polymerization solvent and a cyclization catalyst, the cyclization degree is further reduced without deterioration in the devolatilization step described later by further heating to 200 ° C. or higher under pressure in a pressure device. An acrylic polymer having a ring structure in the main chain that is high and has excellent heat resistance can be obtained in a solution state.

  The reactor that can be employed in the cyclization condensation reaction is not particularly limited, and examples thereof include an autoclave, a kettle reactor, a devolatilization apparatus including a heat exchanger and a devolatilization tank, and the like. Also, a vented extruder suitable for the cyclization reaction using the devolatilization step at the same time can be used.

  The heating temperature and the heating time are not particularly limited. For example, when an autoclave is used, the heating temperature is preferably 40 to 300 ° C., and the heating time is preferably 1 to 20 hours, more preferably 2 -10 hours. By taking such heating temperature and heating time, the possibility of problems such as a decrease in the cyclization reaction rate and coloring or decomposition of the resin can be reduced.

  In this way, by performing a cyclization condensation reaction using the acidic substance or basic substance as a cyclization catalyst, the hydroxyl group or carboxyl group present in the molecular chain of the acrylic polymer and the ester group are cyclized. Thus, an acrylic polymer having a lactone ring structure or a glutaric anhydride structure in the main chain can be obtained.

  Moreover, an acrylic polymer having an N-substituted maleimide structure or a maleic anhydride structure in the main chain is obtained by copolymerizing an acrylic polymer with N-substituted maleimide or maleic anhydride.

  Furthermore, an acrylic polymer having a glutarimide structure can be obtained by adding an imidizing agent to the acrylic polymer. Examples of imidizing agents include aliphatic amines such as methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, tert-butylamine, n-hexylamine, cyclohexylamine; aniline, toluidine Aromatic amines such as trichloroaniline; urea compounds that generate amines by heating, such as urea, 1,3-dimethylurea, 1,3-diethylurea, 1,3-dipropylurea;

(C. Volatilization process)
In the present invention, the devolatilization step described in JP-A-2000-230016, JP-A-2007-262396, JP-A-2007-262399, etc. can be used in combination with the cyclization reaction.

  The devolatilization step refers to a step of removing a volatile component such as a solvent and a residual monomer and alcohol produced as a by-product in the cyclization step under a reduced pressure heating condition as necessary. By this step, it is possible to reduce the possibility of problems such as coloring due to deterioration during molding based on residual volatile content in the generated resin, and molding defects such as bubbles and silver streaks.

  As a preferable form of the devolatilization step, a method in which the cyclization condensation reaction is performed in the presence of a solvent and the devolatilization step is used in combination during the cyclization condensation reaction can be exemplified. In this case, a mode in which the devolatilization step is used throughout the cyclization condensation reaction and a mode in which the devolatilization step is not used over the entire cyclization condensation reaction but only in a part of the process. In the method using the devolatilization step in combination, the alcohol produced as a by-product in the condensation cyclization reaction is forcibly devolatilized and removed, so that the equilibrium of the reaction is advantageous for the production side.

  In the method using the devolatilization step in combination, the alcohol produced as a by-product in the condensation cyclization reaction is forcibly devolatilized and removed, so that the equilibrium of the reaction is advantageous for the production side.

  In the case of a form in which a devolatilization step is used throughout the cyclization condensation reaction, the apparatus to be used is not particularly limited, but a devolatilization apparatus comprising a heat exchanger and a devolatilization tank in order to perform the present invention more effectively. It is preferable to use an extruder equipped with a vent, or a device in which the devolatilizer and the extruder are arranged in series, and it is more preferable to use a devolatilizer comprising a heat exchanger and a devolatilization tank or an extruder equipped with a vent. preferable.

  In the case of using a devolatilizer comprising the heat exchanger and the devolatilization tank, the reaction treatment temperature is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. If the reaction treatment temperature is lower than 150 ° C., the cyclization reaction may be insufficient and the residual volatile matter may increase, and if it is higher than 350 ° C., coloring or decomposition may occur.

  In the case of using a devolatilizer comprising the heat exchanger and the devolatilization tank, the pressure during the reaction treatment is preferably within a range of 931 to 1.33 hPa (700 to 1 mmHg), and 798 to 66.5 hPa (600 to 50 mmHg). ) Is more preferable. When the pressure is higher than 931 hPa, there is a problem that volatile components including alcohol easily remain, and when the pressure is lower than 1.33 hPa, there is a problem that industrial implementation becomes difficult.

  When using the extruder with a vent, one or a plurality of vents may be used, but it is preferable to have a plurality of vents. In the case of using the vented extruder, the reaction treatment temperature is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. If the temperature is lower than 150 ° C., the cyclization condensation reaction may be insufficient and the residual volatile content may increase. If the temperature is higher than 350 ° C., coloring or decomposition may occur.

  In the case of using the extruder with a vent, the pressure during the reaction treatment is preferably within a range of 931 to 1.33 hPa (700 to 1 mmHg), and more preferably within a range of 798 to 13.3 hPa (600 to 10 mmHg).

  When the pressure is higher than 931 hPa, there is a problem that volatile components including alcohol easily remain, and when the pressure is lower than 1.33 hPa, there is a problem that industrial implementation becomes difficult.

  In the case of using the devolatilization step throughout the cyclization reaction, the physical properties of the acrylic polymer having a ring structure in the main chain obtained under severe heat treatment conditions may be deteriorated. It is preferable to use a catalyst for a dealcoholization reaction and under a mild condition as much as possible using an extruder with a vent.

  In the case of using a devolatilization step throughout the cyclization condensation reaction, preferably, the polymer obtained in the polymerization step is introduced into the cyclization condensation reactor system together with a solvent. Then, it may be passed once again through the reactor system such as an extruder with a vent.

  The devolatilization step may be used in a part of the process without being used together throughout the entire cyclization reaction. For example, the apparatus for producing the polymer is further heated, and if necessary, a part of the devolatilization step is used together to advance the cyclization condensation reaction to some extent in advance, and then the devolatilization step is used at the same time. In this mode, the cyclization condensation reaction is performed to complete the reaction.

  In the embodiment in which the devolatilization step is used throughout the cyclization condensation reaction described above, for example, when the polymer is heat-treated at a high temperature of about 250 ° C. or higher using a twin-screw extruder, a heat history is obtained. Depending on the difference, partial decomposition or the like may occur before the cyclization reaction occurs, and the physical properties of the acrylic polymer having a ring structure in the main chain may be deteriorated.

  Therefore, if the cyclization reaction is allowed to proceed to some extent before carrying out the cyclization reaction using the devolatilization step at the same time, the reaction conditions in the latter half can be relaxed, and the physical properties of the acrylic polymer having the resulting ring structure can be reduced. Since deterioration can be suppressed, it is preferable.

  A particularly preferred form is a form in which the devolatilization step is started after a while from the start of the cyclization condensation reaction, that is, the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are cyclized in advance. A form in which a condensation reaction is performed to increase the cyclization reaction rate to some extent and then a cyclization condensation reaction in which a devolatilization step is simultaneously used is performed.

  Specifically, for example, a cyclization reaction is allowed to proceed to a certain reaction rate in the presence of a solvent in advance using a kettle-type reactor, and then a reactor equipped with a devolatilizer, for example, heat exchange Preferred is a mode in which the cyclization condensation reaction is completed with a devolatilizer comprising a vessel and a devolatilization tank, an extruder with a vent, or the like. Particularly in this form, it is more preferable that a cyclization catalyst is present.

  As described above, a method in which the polymer obtained in the polymerization step is preliminarily subjected to a cyclization condensation reaction to increase the cyclization reaction rate to some extent, and then a cyclization condensation reaction using the devolatilization step simultaneously is performed. This is a preferred form for obtaining an acrylic polymer having a structure.

  With this form, an acrylic polymer having a ring structure with a higher cyclization reaction rate, a higher glass transition temperature, and excellent heat resistance can be obtained. In this case, as a measure of the cyclization reaction rate, the weight loss rate between 150 and 300 ° C. in the dynamic TG measurement shown in the examples is preferably 2% or less, more preferably 1.5% or less. More preferably 1% or less.

  The reactor that can be employed in the cyclization condensation reaction that is performed in advance before the cyclization condensation reaction using the devolatilization process at the same time is not particularly limited, but preferably an autoclave, a kettle reactor, a heat exchanger, and a devolatilization tank A vented extruder suitable for the cyclization reaction using the devolatilization step at the same time can also be used.

(D. Neutralization step)
As described above, when a cyclization condensation reaction is performed using an acidic substance or a basic substance as a cyclization catalyst, if the catalyst remains, the heat resistance of the resulting acrylic resin composition is adversely affected. Need to be neutralized. If the catalyst is an acidic substance, the catalyst may be neutralized using a basic substance. Conversely, if the catalyst is a basic substance, the catalyst may be neutralized using an acidic substance. That's fine.

  As the basic substance and acidic substance used in the neutralization step, those described in (b. Cyclization step) can be used. In the neutralization step, the basic substance or acidic substance may be used alone or in combination of two or more. The basic substance or acidic substance may be added in any form such as solid, powder, dispersion, suspension, aqueous solution, etc., and is not particularly limited.

  As described above, conventionally, the present inventors have produced a thermoplastic resin composition by the method described in Patent Document 1 using a basic substance that is 1 molar equivalent to the amount of the cyclization catalyst used. It was. However, there is no problem with short-time production, but when continuous production is performed for a long time, particulate foreign matter increases and the pressure loss in the polymer filter increases, so it can be produced continuously for a long time. The problem of disappearing occurred. This is presumed to be because the ultraviolet absorber contained in the resin composition promotes crystal growth of the salt generated by the reaction between the cyclization catalyst and the basic substance, and this salt becomes a particulate foreign matter. The

  Therefore, the present inventor details the relationship between the amount of the cyclization catalyst used when neutralizing the cyclization catalyst with a basic substance or an acidic substance and the amount of the basic substance or the acidic substance used. After studying and maintaining the function of neutralizing the catalyst by setting the usage amount of the basic substance or acidic substance to 0.1 to 0.7 molar equivalent to the usage amount of the catalyst, It has been found that the obtained resin composition can be maintained in heat resistance, and the generation of particulate foreign matters can be suppressed, thereby solving the above problems.

  The “molar equivalent” means the number of moles of the basic substance or acidic substance relative to 1.0 mole of the catalyst.

  For example, in Example 1 described later, stearyl acid phosphate is used as a cyclization catalyst, and zinc octylate is used as a basic substance for neutralizing the cyclization catalyst. The stearyl acid phosphate used in Example 1 is a product name: Phoslex A-18 manufactured by Sakai Chemical Industry, and is a mixture obtained by mixing an equivalent amount of a monovalent acid having a molecular weight of 602 and a divalent acid having a molecular weight of 350.

  Here, the molecular weight per acid valence is 602 ÷ 3 + 350 × 2 ÷ 3 = 434. In Example 1, 0.05 parts by weight of 2-ethylhexyl phosphate was added to 50 parts by weight of monomers (total of MMA and MHMA), and the addition amount of the cyclization catalyst was 1000 ppm with respect to the monomer (to resin). It becomes.

  Moreover, in Example 1, the polymerization solution which passed through the cyclization process was extruded into the vent type screw twin screw extruder at 24 parts by weight / hour in terms of resin, and the cyclization catalyst was 24 × 1000 ÷ 1 million. = 0.024 parts by weight / hour.

  On the other hand, the zinc octylate has a molecular weight of 65.4 ÷ 0.18 = 363 when the atomic weight of zinc is 65.4. Therefore, to neutralize the 2-ethylhexyl phosphate using 1 molar equivalent, 0.024 × 363 ÷ 434 = 0.020 parts by weight of zinc octylate is required.

  In Example 1, a mixed solution of a basic substance / ultraviolet absorber for neutralizing the antioxidant / cyclization catalyst was added at 0.724 parts by weight / hour. Of these, a 10% toluene solution of the basic substance (zinc octylate) was charged at 0.724 × 9.1 ÷ 100 = 0.0659 parts by weight / hour. Therefore, the basic substance (zinc octylate) is added at 1/10 of 0.00659 parts by weight / hour.

  Therefore, the usage-amount of the said basic substance (zinc octylate) will be 0.3 molar equivalent with respect to the usage-amount of the said cyclization catalyst.

  When the use amount of the basic substance or acidic substance used in the neutralization step is less than 0.1 molar equivalent to the use amount of the catalyst, the action of neutralizing the catalyst becomes insufficient, and molding is performed. Occasionally, thickening occurs due to foaming or cross-linking between polymers, and the heat resistance, mechanical strength, and moldability of the resulting resin composition may be reduced.

  In addition, when the amount of the basic substance or acidic substance used in the neutralization step exceeds 0.7 molar equivalents relative to the amount of the catalyst used, the ultraviolet absorbent is converted into salt crystals produced by the neutralization reaction. Since growth is promoted and the amount of particulate foreign matter increases, problems in appearance and optical properties may occur. When performing filtration with a polymer filter (the filtration step described below), particulate foreign matter The possibility of clogging the filter and increasing pressure loss increases. Therefore, problems such as breakage of the polymer filter and shortening of the time for continuous production may occur, leading to a decrease in production efficiency.

  As described above, the present inventor has found that the ratio of the amount of the catalyst used to the amount of the basic substance or acidic substance used in the neutralization step increases the amount of particulate foreign matter, and thus continuously produces a resin composition. For the first time, it has been found that it has a great influence on the possible time, and in contrast to this, the amount of the basic substance or acidic substance used is 0.1 to 0.7 molar equivalent to the amount of the catalyst used. It was discovered for the first time that the problem can be solved.

  In Examples described later, the usage amount of the basic substance or acidic substance used in the neutralization step was set to 0.1 molar equivalent, 0.3 molar equivalent, and 0.5 molar equivalent relative to the usage amount of the catalyst. In this case, it can be seen that the increase in pressure loss in the polymer filter and the amount of particulate foreign matter in the pellet are remarkably suppressed.

  As shown in the examples and comparative examples described later, when the above-mentioned zinc octylate is used in an amount of 0.3 molar equivalent to the cyclization catalyst, when 0.5 molar equivalent is used, when 1.0 molar equivalent is used The degree of increase in the pressure loss of the polymer filter per hour and the occurrence of particulate foreign matter in the pellets were examined. When 0.5 molar equivalent was used, the number of particulate foreign matters in 20 μm square was determined as an example. The number was close to less than 15 determined as “◯” in FIG. And when 1.0 molar equivalent was used, it was 59 pieces.

  Therefore, when the amount of the basic substance or acidic substance used is more than 0.5 molar equivalent and not more than 0.7 molar equivalent to the amount of the catalyst used, the treatment efficiency of the filtration with the polymer filter is affected. It is considered that the level is not given.

  The timing of mixing the basic substance or acidic substance used in the neutralization step is after the catalyst is added and the cyclization reaction is sufficiently performed in the production of the acrylic polymer, and before the filtration step described later is performed. There is no particular limitation.

  For example, the basic substance or acidic substance is added at a predetermined stage during the production of the acrylic polymer, or the cyclization catalyst is added to the acrylic polymer and heat-treated to advance the cyclization reaction, and then the base is added. A method of adding an organic substance or an acidic substance, or manufacturing an acrylic polymer, and then simultaneously kneading and kneading the acrylic polymer, the basic substance or the acidic substance, other components, etc .; After producing the polymer, a method of dissolving the acrylic polymer, the basic substance or acidic substance, and other components in a solvent; the acrylic polymer and other components are heated and melted, A method of adding a basic substance or an acidic substance and kneading; the acrylic polymer is heated and melted, and the basic substance, the acidic substance or other components are added thereto. How to kneading; and the like.

(E. UV absorber)
The acrylic resin composition obtained by the production method according to the present invention contains an ultraviolet absorber. Although not particularly limited, the ultraviolet absorber exhibits a role as an ultraviolet absorber, and has a molar extinction coefficient of a maximum absorption wavelength with respect to light in a wavelength range of 300 nm to 380 nm in a chloroform solution of 10,000 (L · mol ⁻¹ · cm ⁻¹ ) or more. In addition, it is preferable that the said ultraviolet absorber does not contain the repeating unit derived from a monomer (namely, it is not a polymer).

  The ultraviolet absorber may be solid or liquid at room temperature, but the solid ultraviolet absorber is preferably liquid at room temperature because sublimation during molding tends to be a problem.

  The ultraviolet absorber preferably has a molecular weight of 600 or more, more preferably 650 or more, and still more preferably 700 or more.

  When the molecular weight is less than 600, foaming may occur or the ultraviolet absorbent may bleed out when the acrylic resin composition to which the ultraviolet absorbent has been added is molded. In addition, the ultraviolet absorber may evaporate due to heat applied during molding, resulting in problems such as a decrease in the ultraviolet absorption capacity of the resulting resin molded product, or contamination of the molding apparatus due to the evaporated ultraviolet absorber. is there.

  On the other hand, the upper limit of the molecular weight of the ultraviolet absorber is preferably 10,000 or less, more preferably 8000 or less, and even more preferably 5000 or less. When the molecular weight exceeds 10,000, compatibility with the acrylic resin is lowered, and optical properties such as hue and turbidity of the finally obtained resin molded product are lowered.

  Although the structure of an ultraviolet absorber is not specifically limited, For example, a benzophenone type compound, a salicinate type compound, a benzoate type compound, a triazole type compound, a triazine type compound, etc. are mentioned. Among these, a compound having a hydroxyphenyltriazine skeleton is preferable.

  The hydroxyphenyl triazine skeleton is a skeleton ((2-hydroxyphenyl) -1,3,5-triazine skeleton) composed of triazine and three hydroxyphenyl groups bonded to the triazine. The hydrogen atom of the hydroxyl group in the hydroxyphenyl group forms a hydrogen bond with the nitrogen atom of triazine, and the formed hydrogen bond increases the action of the phenyl triazine as a chromophore.

  In the ultraviolet absorber having a molecular weight of 600 or more, since the three hydrogen bonds are formed, the action as a chromophore possessed by phenyltriazine can be further increased, and a high ultraviolet absorbing ability can be obtained with a small addition amount.

  In addition, when the said ultraviolet absorber consists of a mixture of 2 or more types of compounds, it is preferable that the compound which is a main component has a hydroxyphenyl triazine frame | skeleton. The main component in this specification means a component having the highest content (content), and the content is typically 50% or more.

  A substituent such as an alkyl group or an alkyl ester group may be bonded to the hydroxyphenyl group in the hydroxyphenyltriazine skeleton, but it is preferable that the substituent does not have a structure that can be a crosslinking point with a resin. . The structure that can be a crosslinking point is, for example, a functional group such as a hydroxyl group, a thiol group, or an amine group, or a double bond.

The hydroxyphenyl group has a hydroxyl group as a substituent, but the hydroxyl group directly bonded to the benzene ring does not form a crosslinked structure with the resin, and thus is not treated as a structure that can be a crosslinking point with the resin. The alkyl ester group is preferably a group represented by the formula “—CH (—R) C (═O) OR ′”, wherein R is a hydrogen atom or a methyl group, and R ′ Is a linear or branched alkyl group.

  If there is a structure that can be a crosslinking point with an acrylic resin in the substituent of the hydroxyphenyl group in the hydroxyphenyltriazine skeleton, the possibility that a gel is generated during molding of the resin composition increases.

  Although the ultraviolet absorber which can be used is illustrated below, an ultraviolet absorber is not limited to these.

  Examples of the benzophenone compounds include 2,4-dihydroxybenzophenone, 4-n-octyloxy-2-hydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-n-octyl. Examples thereof include oxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 1,4-bis (4-benzoyl-3-hydroxyphenone) -butane and the like.

  Examples of the silicate compound include pt-butylphenyl silicate. Examples of the benzoate compound include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate.

  Examples of triazole compounds include 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (3,5 -Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4 , 6-Bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H) -benzotriazole-2- Yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-butylpheno 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methyl-6 -(3,4,5,6-tetrahydrophthalimidylmethyl) phenol, methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction products, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 3- (2H-benzotri Zol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy-C7-9 side chain and straight chain alkyl ester, 2,2-methylenebis [6- (2H-benzotriazole-2- Yl) -4- (1,1,3,3-tetramethylbutyl) phenol].

  Further, triazine compounds include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2- Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-tria 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl)- 1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyethoxy) -1,3,5-triazine, 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (3-alkyloxy- 2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton (alkyloxy; long-chain alkyloxy groups such as octyloxy, nonyloxy, decyloxy, etc.) Line absorber, 2,4,6-tris (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-octyloxyphenyl)- 1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-benzyl) Oxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4- (1- (2-ethoxyhexyloxy) -1-oxopropan-2-yloxy) phenyl) -1 , 3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy- 3-methyl -4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4 , 6-Tris (2-hydroxy-3-methyl-4-benzyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-propoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2- Hydroxy-3-methyl-4-methoxycarbonylpropyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxycarbonylethyl) Oxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4- (1- (2-ethoxyhexyloxy) -1-oxopropan-2-yloxy) Phenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (3-alkyloxy-2-hydroxypropyloxy) -5-α -Cumylphenyl] -s-triazine skeleton (alkyloxy; long-chain alkyloxy groups such as octyloxy, nonyloxy, decyloxy, etc.)

  Examples of commercially available products include “Tinuvin 1577”, “Tinuvin 460”, “Tinuvin 477” (manufactured by BASF Japan) as triazine-based UV absorbers, and “Adeka Stub LA-31” (manufactured by ADEKA) as triazole-based UV absorbers. It is done.

  Moreover, the triazine type compound which has a structure represented by following General formula (10) can also be utilized suitably as a ultraviolet absorber.

(In the formula, R ¹³ is a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or alkenyl group having 3 to 8 carbon atoms, an aryl group having 6 to 18 carbon atoms, or 7 carbon atoms. Represents an alkylaryl group or an arylalkyl group having ˜18, and R ¹⁴ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 3 to 8 carbon atoms.)
In the above formula, as the linear or branched alkyl group having 1 to 12 carbon atoms represented by R ¹³ ,
For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,
Tertiary butyl, amyl, tertiary amyl, hexyl, octyl, secondary octyl, tertiary octyl,
Examples include linear or branched alkyl groups such as 2-ethylhexyl, decyl, undecyl, dodecyl and the like. Examples of the cycloalkyl group having 3 to 8 carbon atoms include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and the like.

In the above formula, examples of the alkyl group having 1 to 8 carbon atoms represented by R ¹⁴ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, tert-amyl, Examples include octyl and tertiary octyl.

Examples of the alkenyl group having 3 to 8 carbon atoms represented by R ¹³ and R ¹⁴ include linear and branched propenyl, butenyl, pentenyl, hexenyl, heptenyl and octenyl regardless of the position of the unsaturated bond.

Examples of the aryl group having 6 to 18 carbon atoms represented by R ¹³ include phenyl, naphthyl, and biphenyl. Examples of the alkylaryl group having 7 to 18 carbon atoms include methylphenyl and dimethylphenyl. , Ethylphenyl, octylphenyl and the like, and examples of the arylalkyl group having 7 to 18 carbon atoms include benzyl, 2-phenylethyl, 1-methyl-1-phenylethyl and the like. Examples of the aryl group having a substituent or interruption include 4-methylphenyl, 3-chlorophenyl, 4-benzyloxyphenyl, 4-cyanophenyl, 4-phenoxyphenyl, 4-glycidyloxyphenyl, 4-isocyanurate phenyl, and the like. Is mentioned.

Examples of the substituent represented by R ¹³ and the optionally substituted alkyl group and cycloalkyl group include 2-hydroxypropyl, 2-methoxyethyl, 3-sulfonyl-2-hydroxypropyl, 4-methylcyclohexyl, and the like. Is mentioned.

  The said ultraviolet absorber can be used individually or in combination of 2 or more types. The content of the ultraviolet absorber in the acrylic resin composition is not particularly limited, but it is possible to maintain transparency by preventing yellowing of the acrylic resin composition, and from the viewpoint of not causing foaming or bleeding out, It is preferable that it is 0.01 to 5 weight%.

  In the method for producing an acrylic resin composition according to the present invention, the ultraviolet absorber is mixed with the above-mentioned “acrylic polymer having a ring structure in the main chain” and the acrylic resin composition as a final product. Good.

  The timing of mixing the “acrylic polymer having a ring structure in the main chain” and the ultraviolet absorber is not particularly limited, but the acrylic resin composition according to the present invention is used for an optical member such as a film. In order to keep the appearance of a film or the like favorable when used, it is preferably mixed with the above “acrylic polymer having a ring structure in the main chain” before passing through the filtration step described later.

  For example, the ultraviolet absorber may be mixed with the reaction system in the polymerization step or in the cyclization step. In this case, the above-mentioned “acrylic polymer having a ring structure in the main chain” has not yet been formed when the ultraviolet absorber is mixed in the reaction system, but after the completion of the cyclization step, The acrylic polymer having a ring structure ”and the ultraviolet absorber are mixed.

  Moreover, the said ultraviolet absorber may be mixed with the said "acrylic polymer which has a ring structure in a principal chain" in the said neutralization process. Further, after completion of the neutralization step, it may be mixed with the “acrylic polymer having a ring structure in the main chain” before passing through a filtration step described later.

  In the present invention, as described above, the usage amount of the basic substance or acidic substance used in the neutralization step is 0.1 to 0.7 molar equivalents relative to the usage amount of the catalyst. Even if the ultraviolet absorber is mixed before the filtration with the polymer filter, the generation of the particulate foreign matter considered to be caused by the presence of the ultraviolet absorber does not become a problem.

(F. Filtration process)
A filtration process is a process of filtering the acrylic resin composition which passed through the said neutralization process using a polymer filter. Since the foreign substance which exists in an acrylic resin composition can be removed by a filtration process, the fault on the external appearance of the obtained resin composition can be reduced.

  In the present invention, as described above, the usage amount of the basic substance or acidic substance used in the neutralization step is 0.1 to 0.7 molar equivalents relative to the usage amount of the catalyst. The formation of particulate foreign matter is remarkably suppressed. Therefore, an increase in the pressure loss of the polymer filter can be suppressed in the filtration step, and the filtration step can be performed continuously for a long time.

  The configuration of the polymer filter is not particularly limited, but a polymer filter in which a large number of leaf disk filters are arranged in a housing can be suitably used. The filter material of the leaf disk type filter may be any of a type in which a metal fiber nonwoven fabric is sintered, a type in which metal powder is sintered, a type in which several metal meshes are laminated, or a hybrid type in which they are combined. The sintered type is most preferred.

  The filtration accuracy with the polymer filter is not particularly limited, but is usually 15 μm or less, preferably 10 μm or less, more preferably 5 μm or less. When the filtration accuracy is 1 μm or less, the residence time of the acrylic resin composition becomes long, so that the thermal deterioration of the composition becomes large, and the productivity may be lowered.

In the polymer filter, the filtration area with respect to the resin treatment amount per hour is not particularly limited, and can be appropriately set according to the treatment amount of the resin composition. The filtration area is, for example, 0.001 to 0.15 m ² / (kg / h).

  The shape of the polymer filter is not particularly limited. For example, an inner flow type having a plurality of resin flow ports and a resin flow path in the center pole; an inner peripheral surface of the leaf disk filter at a plurality of vertices or faces And an external flow type having a resin flow path on the outer surface of the center pole. In particular, it is preferable to use an external flow type in which the resin stays are small.

  Although there is no restriction | limiting in particular in the residence time of the resin composition in a polymer filter, 20 minutes or less are preferable, 10 minutes or less are more preferable, and 5 minutes or less are further more preferable. Further, the filter inlet pressure and the filter outlet pressure during filtration are, for example, 3 to 15 MPa and 0.3 to 10 MPa, respectively, and the pressure loss (the pressure difference between the filter inlet pressure and the outlet pressure) is 1 MPa to 15 MPa. A range is preferred. When the pressure loss is less than 1 MPa, the flow path through which the acrylic resin composition passes through the filter tends to be biased, and the quality of the obtained acrylic resin composition tends to deteriorate. On the other hand, when the pressure loss exceeds 15 MPa, the polymer filter is easily damaged.

  In the manufacturing method according to the present invention, an increase in the pressure loss of the polymer filter can be suppressed, so that the increase in the pressure loss of the polymer filter before and after the filtration step can be 0.06 MPa / hr or less. The increase is more preferably 0.05 MPa / hr or less, and further preferably 0.04 MPa / hr or less.

  What is necessary is just to set suitably the temperature of the acrylic resin composition introduce | transduced into a polymer filter according to the melt viscosity, for example, it is 250-300 degreeC, 255-300 degreeC is preferable and 260-300 degreeC is more preferable.

  The specific process of obtaining an acrylic resin composition with few foreign substances and colored substances by filtration using a polymer filter is not particularly limited. For example, (1) a process of forming and filtering an acrylic resin composition in a clean environment, and subsequently molding the acrylic resin composition in a clean environment, (2) an acrylic resin composition having foreign matter or colored matter A process in which the acrylic resin composition is subsequently molded in a clean environment after being filtered in a clean environment, and (3) the acrylic resin composition having foreign matter or colored substances is filtered in a clean environment at the same time. And a process of performing molding. You may perform the filtration process of the resin composition by a polymer filter in multiple times for each process.

  The molding is not particularly limited and may be molded into an arbitrary shape. For example, pelletization using a pelletizer or film blending by extruding and kneading the resulting mixture after pre-blending the film raw material with a conventionally known mixer such as an omni mixer can be performed.

  The mixer used for extrusion kneading is not particularly limited. For example, a conventionally known mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used.

  Examples of the film forming method include conventionally known film forming methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Of these film forming methods, the solution casting method (solution casting method) and the melt extrusion method are particularly suitable.

  In addition, when filtering a resin composition with a polymer filter, it is preferable to install a gear pump between an extruder and a polymer filter, and to stabilize the pressure of the resin composition in a filter.

<Acrylic resin composition>
The acrylic resin composition obtained by the production method according to the present invention essentially contains the above “acrylic polymer having a ring structure in the main chain” and an ultraviolet absorber. The acrylic resin composition preferably contains 50% by weight or more and less than 100% by weight of an acrylic polymer having a ring structure in the main chain. Thereby, in addition to the outstanding transparency and heat resistance, the said acrylic resin composition can obtain desired characteristics, such as mechanical strength and moldability.

  The content of the ultraviolet absorber is preferably 0.01% by weight or more and 5% by weight or less as described above. Therefore, the acrylic resin composition comprises 50 wt% or more and less than 100 wt% of the acrylic polymer having a ring structure in the main chain, and 0.01 wt% or more and 5 wt% or less of the ultraviolet absorber, for a total of 100 wt%. It is preferable to contain so that it may become.

  However, it is not restricted to this, The said acrylic resin composition may contain the other component. For example, a thermoplastic resin other than the “acrylic polymer having a ring structure in the main chain” (hereinafter referred to as “other thermoplastic resin”) is contained in the acrylic resin composition in an amount of less than 50% by weight. May be.

  That is, the acrylic resin composition comprises 50 wt% or more and less than 100 wt% of the “acrylic polymer having a ring structure in the main chain”, 0.01 wt% or more and 5 wt% or less of the ultraviolet absorber. The thermoplastic resin may be contained in an amount of less than 50% by weight, and the total of these may be 100% by weight.

  Examples of the other thermoplastic resins include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resins; Styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; nylon 6, nylon 66, polyamides such as nylon 610; polyacetal: polycarbonate; polyphenylene oxide; polyphenylene sulfide: polyetheretherketone; polysulfone; Rubbery polymer such as polybutadiene rubber, or ABS resin containing an acrylic rubber, ASA resin; Li polyether sulfone; polyoxyethylene Penji alkylene; polyamideimide, and the like.

  The rubbery polymer preferably has on its surface a graft portion having a composition compatible with the above “acrylic polymer having a ring structure in the main chain”, and the rubbery polymer is in the form of particles. In this case, the average particle diameter is preferably 300 nm or less, more preferably 150 nm or less, from the viewpoint of improving transparency when the acrylic resin composition is used as a resin film.

  Among the thermoplastic resins exemplified above, cyan is excellent in compatibility with the above-mentioned “acrylic polymer having a ring structure in the main chain”, in particular, compatibility with an acrylic polymer having a lactone ring structure in the main chain. A copolymer containing a structural unit derived from a vinyl fluoride monomer and a structural unit derived from an aromatic vinyl monomer is preferred. The copolymer is, for example, a styrene-acrylonitrile copolymer or a vinyl chloride resin.

  The acrylic resin composition may contain an antioxidant. As the antioxidant, for example, a phenol-based antioxidant, a thioether-based antioxidant, a phosphoric acid-based antioxidant, and the like can be used, and specific examples thereof are exemplified in JP-A-2009-52021. Antioxidants can be suitably used.

  The content of the antioxidant in the acrylic resin composition is, for example, 0 to 10% by weight, preferably 0 to 5% by weight, when the acrylic resin composition is 100% by weight, for example, 0 More preferably, the content is 0.01 to 2% by weight, and even more preferably 0.05 to 1% by weight.

  The acrylic resin composition includes, as other additives, for example, a stabilizer such as a light-resistant stabilizer, a weather-resistant stabilizer, and a heat stabilizer; a reinforcing material such as glass fiber and carbon fiber; a near-infrared absorber; Tris (dibromopropyl) ) Flame retardants such as phosphate, triallyl phosphate and antimony oxide; antistatic agents represented by anionic, cationic and nonionic surfactants; colorants such as inorganic pigments, organic pigments and dyes; organic fillers and inorganics Filler; resin modifier; plasticizer; lubricant; flame retardant.

  The content of the other additives in the acrylic resin composition is, for example, 0 to 5% by weight, preferably 0 to 2% by weight, when the acrylic resin composition is 100% by weight. 0.5% by weight is more preferred.

  As described above, for example, the ultraviolet absorber may be mixed in the polymerization step with respect to the reaction system, may be mixed in the cyclization step, or may be mixed in the neutralization step. Good. As a result, an acrylic resin composition containing the above “acrylic polymer having a ring structure in the main chain” and an ultraviolet absorber can be obtained.

  For example, after the acrylic resin composition is obtained, the other thermoplastic resin, antioxidant, and other additives are contained in the acrylic resin composition by a conventionally known method (for example, melt kneading). Can do.

  Although the glass transition temperature (Tg) of the said acrylic resin composition is not specifically limited, From a viewpoint of providing high heat resistance, it is preferable that it is 110 degreeC or more, 115 degreeC or more is more preferable, 120 degreeC or more is further more preferable. . In the examples described later, an acrylic resin composition having a Tg of 120 ° C. or higher is obtained. In addition, Tg in this specification shall be the value calculated | required by the starting point method using the differential scanning calorimeter (DSC) based on prescription | regulation of JISK7121.

  In the acrylic resin composition, the yellowness (YI) of a 15% chloroform solution of the acrylic resin composition measured by ASTM E313 is preferably 0 or more and 15 or less, and more preferably 5 or more and 15 or less. In the method according to the present invention, as described above, since the crystal growth of the salt in the foaming and neutralization reaction caused by the ultraviolet absorber is suppressed, an acrylic resin composition having such a low YI can be obtained. . The YI of the acrylic resin composition can be confirmed by the method described in the examples.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention. First, the evaluation method of the acrylic resin composition produced in a present Example is demonstrated.

[Glass transition temperature (Tg)]
The Tg of the resin was determined in accordance with JIS K7121 regulations. Specifically, a differential scanning calorimeter (manufactured by Rigaku, DSC-8230) is used, and a sample of about 10 mg is heated from normal temperature to 200 ° C. (temperature increase rate: 20 ° C./min) in a nitrogen gas atmosphere. The DSC curve was evaluated by the starting point method. Α-alumina was used as a reference.

[Pyrolysis temperature]
The thermal decomposition temperature of the polymer was raised from room temperature to 500 ° C. in a nitrogen gas atmosphere using a differential differential thermobalance (Rigaku, Thermo Plus 2 TG-8120). The rate was 10 ° C./min). At this time, isothermal control was performed stepwise so that the weight reduction rate value was 0.05 wt% / second or less between 150 ° C. and 500 ° C.

[Weight average molecular weight]
The weight average molecular weight of the resin was determined by gel conversion using gel permeation chromatography (GPC). The apparatus and measurement conditions used for the measurement are as shown in Table 1 below.

[YI]
The YI (yellowness) of the acrylic resin composition was measured by ASTM E313. That is, a solution obtained by dissolving 3 g of the resin composition in 17 g of chloroform was measured using a colorimetric color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., ZE6000).

[Observation of particulate foreign matter in pellets]
A pellet described later was press-molded at 250 ° C. to produce a film having a thickness of 90 μm. The internal state of the obtained film was observed using a laser microscope (VK-9700, manufactured by KEYENCE) with a magnification of 50 times, and the number of particulate foreign matters in 20 μm square was counted at arbitrary three locations. The average value of less than 15 was rated as ◯, 15 or more and less than 30 as Δ, and 30 or more as confirmed as x.

  The “particulate foreign matter” refers to a particulate substance found in the observation region by the observation. The shape of the particles is not limited.

Example 1
40 parts by weight of methyl methacrylate (MMA), 10 parts by weight of methyl 2- (hydroxymethyl) acrylate (MHMA), and a polymerization solvent in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe Was added to 50 parts by weight of toluene, and the temperature was raised to 105 ° C. while passing nitrogen through the toluene.

  When refluxing with a rise in temperature started, 0.03 parts by weight of t-amyl peroxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and 0.06 parts by weight of While the above t-amyl peroxyisononanoate was added dropwise over 2 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.05 parts by weight of stearyl acid phosphate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: Phoslex A-18) is added to the resulting polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst). The cyclization condensation reaction was allowed to proceed for 2 hours under reflux at 90 to 110 ° C. to obtain a polymerization solution.

  The acrylic resin having a lactone ring structure in the main chain was formed by a series of reactions. This is because the composition of the resin pellet finally formed in this example was separately determined by nuclear magnetic resonance (NMR) and infrared spectroscopy (IR). ) Was used for analysis.

Next, the obtained polymerization solution was passed through a heat exchanger and heated up to 240 ° C., and the cyclization condensation reaction was further advanced at the temperature, and then the polymerization solution was subjected to a vent type screw twin screw extruder (L / D = 52) was introduced at a treatment rate of 24 parts by weight / hour in terms of resin amount, and devolatilization was performed.
The vent type screw twin screw extruder includes one rear vent and four fore vents (referred to as first, second, third, and fourth vents from the upstream side), and the third vent, the fourth vent, A side feeder is provided between them, and a gear pump and a leaf disk type polymer filter (filtration accuracy: 5 μm) are arranged at the tip. The devolatilization conditions were a barrel temperature of 240 ° C., a rotation speed of 120 rpm, and a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg).

  At this time, a separately prepared mixed solution of the basic substance / ultraviolet absorber for neutralizing the antioxidant / cyclization catalyst was added from the back of the first vent at a charging rate of 0.724 parts by weight / hour. I put it in.

  As a mixed solution of the basic substance / ultraviolet absorber for neutralizing the antioxidant / cyclization catalyst, 0.9 parts by weight of Irganox 1010 (manufactured by BASF Japan) and 0.9 weight as an antioxidant are used. Part of ADK STAB AO-412S (manufactured by ADEKA), 68 parts by weight of tinuvin 477 (manufactured by BASF Japan) as an ultraviolet absorber, and 9.1 parts by weight of octylic acid as a basic substance for neutralizing the cyclization catalyst Zinc (made by Nippon Chemical Industry Co., Ltd., trade name: Nikka octix zinc, zinc content 18% by weight) A 10% by weight toluene solution dissolved in 21 parts by weight of toluene was used.

  At this time, the amount of the basic substance for neutralizing the charged cyclization catalyst was 0.3 molar equivalent of the cyclization catalyst. In addition, a styrene-acrylonitrile copolymer (styrene / acrylonitrile copolymerization ratio of 73% by weight / 27% by weight, weight average molecular weight of 220,000) is charged from the side feeder at a rate of 3 parts by weight / hour. did.

After completion of devolatilization, the polymer in the molten state remaining in the extruder is discharged from the tip of the extruder while filtering with a polymer filter (manufactured by Nagase Sangyo Co., Ltd.), pelletized with a pelletizer, and main chain A transparent pellet of a (meth) acrylic polymer having a lactone ring structure was obtained. The filtration area with respect to the resin processing amount per hour in the polymer filter was 0.02 m ² (kg / h).

  The polymer in a molten state for 12 hours was filtered, and the increase in pressure difference (pressure loss) before and after the polymer filter from the start to the end of filtration was evaluated to be 0.36 MPa. The acrylic resin had a Tg of 123 ° C., a thermal decomposition temperature of 337 ° C., a weight average molecular weight of 151,000, and a YI of 10.8.

(Example 2)
As a mixed solution of an antioxidant / basic substance / ultraviolet absorber for neutralizing the cyclization catalyst, 0.9 parts by weight of Irganox 1010 (manufactured by BASF Japan) and 0.9 parts by weight are used as antioxidants. ADEKA STAB AO-412S (manufactured by ADEKA), 68 parts by weight of tinuvin 477 (manufactured by BASF Japan) as an ultraviolet absorber, and 3 parts by weight of zinc octylate (Japan) as a basic substance for neutralizing the cyclization catalyst A product obtained by dissolving 10 wt% toluene solution in 27.2 parts by weight of toluene, manufactured by Chemical Industry, trade name: Nikka octix zinc, zinc content 18 wt%) was used.

  The increase in pressure loss in the polymer filter was evaluated in the same manner as in Example 1 except that the mixed solution used was changed in this way. At this time, the amount of the basic substance for neutralizing the charged cyclization catalyst was 0.1 molar equivalent of the cyclization catalyst. The increase in pressure loss was 0.31 MPa. The acrylic resin had a Tg of 123 ° C., a thermal decomposition temperature of 334 ° C., a polymerization average molecular weight of 149,000, and a YI of 10.6.

(Example 3)
As a mixed solution of an antioxidant / basic substance / ultraviolet absorber for neutralizing the cyclization catalyst, 0.9 parts by weight of Irganox 1010 (manufactured by BASF Japan) and 0.9 parts by weight are used as antioxidants. ADEKA STAB AO-412S (manufactured by ADEKA), 68 parts by weight of tinuvin 477 (manufactured by BASF Japan) as a UV absorber, and 15.1 parts by weight of zinc octylate as a basic substance for neutralizing the cyclization catalyst (Nippon Kagaku Sangyo Co., Ltd., trade name: Nikka octix zinc, zinc content 18% by weight) A 10% by weight toluene solution dissolved in 15.1 parts by weight of toluene was used.

  The increase in pressure loss in the polymer filter was evaluated in the same manner as in Example 1 except that the mixed solution used was changed in this way. At this time, the amount of the basic substance for neutralizing the charged cyclization catalyst was 0.5 molar equivalent of the cyclization catalyst. The increase in pressure loss was 0.47 MPa. The acrylic resin had a Tg of 123 ° C., a thermal decomposition temperature of 340 ° C., a polymerization average molecular weight of 152,000, and a YI of 12.5.

(Comparative example)
As a mixed solution of an antioxidant / basic substance / ultraviolet absorber for neutralizing the cyclization catalyst, 0.9 parts by weight of Irganox 1010 (manufactured by BASF Japan) and 0.9 parts by weight are used as antioxidants. ADEKA STAB AO-412S (manufactured by ADEKA), 68 parts by weight of tinuvin 477 (manufactured by BASF Japan) as an ultraviolet absorber, and 30 parts by weight of zinc octylate (Japan) as a basic substance for neutralizing the cyclization catalyst A product obtained by dissolving a 10 wt% toluene solution in 21 parts by weight of toluene, manufactured by Kagaku Sangyo Co., Ltd., trade name: Nikka octix zinc, zinc content 18 wt%) was used. The amount of the basic substance for neutralizing the cyclization catalyst is different from that of the mixed solution used in Example 1.

  The increase in pressure loss in the polymer filter was evaluated in the same manner as in Example 1 except that the mixed solution used was changed in this way. At this time, the amount of the basic substance for neutralizing the charged cyclization catalyst was 1.0 molar equivalent of the cyclization catalyst. The increase in pressure loss was 0.96 MPa. The acrylic resin had a Tg of 123 ° C., a thermal decomposition temperature of 339 ° C., a polymerization average molecular weight of 154,000, and a YI of 22.6.

  The results of Examples 1 to 3 and Comparative Example are summarized in Table 2 below.

  Here, in Example 3, the number of particulate foreign matters in the pellet is “Δ” (15 or more and less than 30 in the above measurement method). For example, even if the manufacturing method according to the present invention is continuously performed for a long time, it is at a level that does not hinder.

  In addition, the number of the measured particulate foreign materials was 0 in Examples 1 and 2, 17 in Example 3, and 59 in the comparative example.

  From the results of Examples 1 to 3 and Comparative Example, the increase in pressure loss can be remarkably suppressed by reducing the molar equivalent of zinc octylate relative to the cyclization catalyst and using 0.1 to 0.7 molar equivalent. And it turns out that heat resistance can be maintained.

  On the other hand, in the comparative example in which the molar equivalent of zinc octylate to the cyclization catalyst exceeds 0.7 molar equivalent, it can be seen that the increase in pressure loss is remarkable and the continuity productivity is greatly reduced.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  In the method for producing an acrylic resin composition according to the present invention, the use amount of a basic substance or an acidic substance for neutralizing the cyclization catalyst is adjusted so that the metal salt particles of the cyclization catalyst do not grow. Therefore, an increase in pressure loss when filtering with a polymer filter can be greatly suppressed, and an acrylic resin composition can be produced continuously for a long time.

  Therefore, the present invention can greatly contribute to the production efficiency of the acrylic resin composition, and therefore can be widely used in all industrial fields using the acrylic resin composition. For example, suitable for fields such as polarizer protective films, optical protective films, retardation films, viewing angle compensation films, light diffusion films, reflective films, antireflection films, antiglare films, brightness enhancement films, conductive films for touch panels, etc. Can be used.

Claims (8)

A method for producing an acrylic resin composition comprising an acrylic polymer having a ring structure in the main chain, and an ultraviolet absorber,
By using an acidic substance or a basic substance as a catalyst, a cyclic condensation reaction of an acrylic polymer is performed, a cyclic structure is formed in the main chain of the polymer, and an acrylic polymer having a cyclic structure in the main chain A cyclization step to obtain
When an acidic substance is used as the catalyst, the catalyst is neutralized with a basic substance, and when a basic substance is used as the catalyst, a neutralization step of neutralizing the catalyst with an acidic substance;
A filtration step of filtering the acrylic resin composition that has undergone the neutralization step using a polymer filter,
The method for producing an acrylic resin composition, wherein the basic substance or acidic substance used in the neutralization step is used in an amount of 0.1 to 0.7 molar equivalents with respect to the catalyst used. .   The method for producing an acrylic resin composition according to claim 1, wherein the ultraviolet absorbent has a molecular weight of 600 or more.   The method for producing an acrylic resin composition according to claim 1 or 2, wherein the ultraviolet absorber is a compound having a hydroxyphenyltriazine skeleton.   The acrylic resin composition according to any one of claims 1 to 3, wherein the acrylic resin composition contains 50 wt% or more and less than 100 wt% of an acrylic polymer having a ring structure in the main chain. A method for producing a resin composition.   The said acrylic resin composition contains the said ultraviolet absorber 0.01 to 5 weight%, The manufacturing method of the acrylic resin composition of any one of Claim 1 to 4 characterized by the above-mentioned. .   The acrylic resin composition according to any one of claims 1 to 5, wherein the yellowness (YI) of a 15% chloroform solution of the acrylic resin composition measured by ASTM E313 is 0 or more and 15 or less. The manufacturing method of the acrylic resin composition as described in a term. An acrylic resin composition containing an acrylic polymer having a ring structure in the main chain, and an ultraviolet absorber,
The ultraviolet absorber is a compound having a molecular weight of 600 or more and having a hydroxyphenyltriazine skeleton,
The acrylic resin composition contains 0.01 wt% or more and 5 wt% or less of the ultraviolet absorber,
The yellowness (YI) of a 15% chloroform solution of the acrylic resin composition measured by ASTM E313 is from 0 to 15,
The acrylic resin composition pellets are press-molded at 250 ° C. to form a 90 μm-thick film. When the internal state of the film is observed with a laser microscope with a magnification of 50 times, it is counted in 20 μm squares at any three locations. An acrylic resin composition having an average number of particulate foreign particles of less than 30. The acrylic resin composition according to claim 7, wherein the acrylic resin composition contains an acrylic polymer having a ring structure in the main chain in an amount of 50 wt% to less than 100 wt%.