JP6305882B2 - Methacrylic resin molded product and method for producing the same - Google Patents

Description

  The present invention relates to a methacrylic resin molded product and a method for producing the same, and more particularly, to a methacrylic resin molded product that is excellent in transparency, weather resistance, and impact resistance and hardly undergoes whitening due to stretch molding or heating, and a method for producing the same. Is.

  Since the methacrylic resin molded article is excellent in transparency, weather resistance, etc., it is used in a wide range of applications. For example, sheet-like methacrylic resin molded products (methacrylic resin plates) are widely used for applications such as lighting equipment covers, signboards, building materials, and game machine covers.

  A methacrylic resin molded product (methacrylic resin cast molded product) produced by a cast polymerization method in which a syrup containing a polymerizable component is injected into a mold and polymerized is excellent in transparency and weather resistance, but has improved impact resistance. It was sought after.

  As a method for improving the impact resistance of a methacrylic resin molded article, it is known to disperse various rubber components in a methacrylic resin (polymethyl methacrylate or the like). For example, a sheet-like methacrylic resin cast molded product in which a polymer obtained by grafting a hard resin component to a rubbery polymer is dispersed is known (see Patent Document 1). In addition, a methacrylic resin having an average molecular weight of 10,000 to 300,000 is dissolved in a monomer mainly composed of methyl methacrylate (hereinafter referred to as “MMA”), and a multilayer structure elastic body as a rubber component is further dispersed. A method for producing a methacrylic resin cast product in which syrup is cast and polymerized is known (see Patent Document 2).

  Furthermore, a methacrylic resin cast molded body, which cast polymerizes syrup composed of MMA and a block copolymer (polymethyl methacrylate-b-polyacrylate n-butyl-b-polymethyl methacrylate, etc.) that is a rubber component. Is known (see Patent Document 3).

  However, the methacrylic resin cast molding added with these rubber components does not have sufficient interfacial adhesion between the rubber component and the methacrylic resin, and when stretch-molded, peeling occurs at the interface between the rubber component and the methacrylic resin, resulting in whitening. There is a case. Furthermore, when the obtained methacrylic resin cast molded body is heated, the refractive index difference between the rubber component and the methacrylic resin is increased and whitening may occur.

Japanese Patent Laid-Open No. 01-252653 Japanese Patent Laid-Open No. 08-151498 Special table 2008-523191

  The present invention has been made in order to solve such problems of the prior art, and the object thereof is a methacrylic resin molded article that is excellent in impact resistance and hardly undergoes whitening due to stretch molding or heating, and a method for producing the same. Is to provide.

In order to achieve the above object, the present invention provides:
[1] Unsaturated monomer (I) containing MMA (hereinafter, simply referred to as “unsaturated monomer (I)”) 70 to 99% by mass, and a partial structure represented by the following general formula (1) ( 1) (Meth) acrylic polymer block (a) having a polymerizable functional group containing (hereinafter simply referred to as “partial structure (1)”) (hereinafter simply referred to as “(meth) acrylic polymer block (a)”) And (meth) acrylic polymer block (b) having no polymerizable functional group (hereinafter simply referred to as “(meth) acrylic polymer block (b)”). Acrylic block copolymer (II) (hereinafter simply referred to as “(meth) acrylic block copolymer (II)”) 1-30% by mass (provided that the unsaturated monomer (I) and (meta) ) Does acrylic block copolymer (II) occupy 100% by mass in total)? Polymerizable component, and the syrup contains a polymerization initiator (III), the production method of the methacrylic resin molded article comprising a step of polymerization was poured into molds made;
[2] The polymerizable functional group obtained by the method for producing a methacrylic resin molded article of the above [1] represented by the following general formula (2); and [3] the method for producing of the above [1] or [2] A methacrylic resin molded product to be achieved.

（式中、Ｒ¹は水素原子または炭素数１〜２０の炭化水素基を表す）

(Wherein R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms)

（式中、Ｒ¹は水素原子または炭素数１〜２０の炭化水素基を表し、Ｒ²およびＲ³は、それぞれ独立して水素原子または炭素数１〜６の炭化水素基を表し、ＸはＯ、Ｓ、またはＮ（Ｒ⁶）（Ｒ⁶は水素原子または炭素数１〜６の炭化水素基を表す）を表し、ｎは１〜２０の整数を表す）
なお、上記一般式（２）で示される重合性官能基を、以下「重合性官能基（２）」と称する。

(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, R ² and R ³ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and X represents O, S, or N (R ⁶ ) (R ⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms), and n represents an integer of 1 to 20)
The polymerizable functional group represented by the general formula (2) is hereinafter referred to as “polymerizable functional group (2)”.

  According to the present invention, it is possible to produce a methacrylic resin molded article that is excellent in impact resistance and hardly undergoes whitening due to stretch molding or heating.

Hereinafter, the present invention will be described in detail.
The method for producing a methacrylic resin molded product of the present invention comprises 70 to 99% by mass of an unsaturated monomer (I), a (meth) acrylic polymer block (a), a (meth) acrylic polymer block (b), (Meth) acrylic block copolymer (II) 1 to 30% by mass (however, the unsaturated monomer (I) and the (meth) acrylic block copolymer (II) are 100% by mass in total) A syrup containing a polymerizable component consisting of a polymerization initiator and a polymerization initiator (III) is injected into a mold and polymerized.

  In the present specification, “(meth) acryl” means a generic name of “methacryl” and “acryl”, and “(meth) acryloyl” described later means a generic name of “methacryloyl” and “acryloyl”. “(Meth) acrylate” means a general term for “methacrylate” and “acrylate”.

The content of the unsaturated monomer (I) in the polymerizable component contained in the syrup is 70 to 99% by mass, and preferably 80 to 95% by mass.
The unsaturated monomer (I) includes MMA. The content of MMA in the unsaturated monomer (I) is preferably 70% by mass or more, more preferably 80% by mass or more, and may be 100% by mass.

  The unsaturated monomer (I) may contain an unsaturated monomer other than MMA (another unsaturated monomer). As another unsaturated monomer, what can be copolymerized with MMA is preferable. Examples of such other unsaturated monomers include (meth) acrylic acid alkyl esters other than MMA such as ethyl (meth) acrylate and methyl acrylate; (meth) acrylic acid aryl esters such as phenyl (meth) acrylate; (Meth) acrylic acid aralkyl esters such as benzyl (meth) acrylate; (meth) acrylic acid hydroxyalkyl esters such as hydroxyethyl (meth) acrylate; glycidyl (meth) acrylate; (meth) acrylic acid; acrylonitrile; acrylamide; Aromatic vinyl compounds such as styrene and α-methylstyrene; vinyl esters such as vinyl acetate; alkenes such as ethylene; conjugated dienes such as butadiene and isoprene; halogenated alkenes such as vinyl chloride, vinylidene chloride and vinylidene fluoride; Acid; maleic acid Fumaric acid, and the like. These other unsaturated monomers may be used alone or in combination of two or more.

The content of the (meth) acrylic block copolymer (II) in the polymerizable component contained in the syrup is 1 to 30% by mass, preferably 5 to 20% by weight.
The (meth) acrylic polymer block (a) included in the (meth) acrylic block copolymer (II) has a polymerizable functional group containing the partial structure (1).
The partial structure (1) is represented by the following general formula (1).

（式中、Ｒ¹は水素原子または炭素数１〜２０の炭化水素基を表す）

(Wherein R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms)

In the general formula (1), examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a sec-butyl group. Group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-pentyl group, neopentyl group Alkyl groups such as n-hexyl group, 2-methylpentyl group, 3-methylpentyl group and n-decyl; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; phenyl group, naphthyl group and the like Aryl groups such as benzyl group and phenylethyl group. Among these, from the viewpoint of increasing the polymerization rate of the (meth) acrylic block copolymer (II), a methyl group and an ethyl group are preferable, and a methyl group is most preferable.

From the viewpoint of increasing the polymerization rate of the (meth) acrylic block copolymer (II), the polymerizable functional group containing the partial structure (1) is preferably the polymerizable functional group (2).
The polymerizable functional group (2) is represented by the following general formula (2).

（式中、Ｒ¹は水素原子または炭素数１〜２０の炭化水素基を表し、Ｒ²およびＲ³はそれぞれ独立して炭素数１〜６の炭化水素基を表し、ＸはＯ、Ｓ、またはＮ（Ｒ⁶）（Ｒ⁶は水素原子または炭素数１〜６の炭化水素基を表す）を表し、ｎは１〜２０の整数を表す）

(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, R ² and R ³ each independently represents a hydrocarbon group having 1 to 6 carbon atoms, and X represents O, S, Or N (R ⁶ ) (R ⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms), and n represents an integer of 1 to 20)

Specific examples and preferred examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ in the general formula (2) include the same hydrocarbon groups as R ^{1 in the} general formula (1).
In the general formula (2), R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and a monomer containing di (meth) acrylate (3) described later. From the viewpoint of easy and direct introduction, a hydrocarbon group having 1 to 6 carbon atoms is preferable. Examples of the hydrocarbon group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, and a 2-methylbutyl group. 3-methylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-pentyl group, neopentyl group, n-hexyl group, 2-methylpentyl group And alkyl groups such as 3-methylpentyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; and aryl groups such as phenyl group. Among these, from the viewpoint of increasing the polymerization rate of the (meth) acrylic block copolymer (II), R ² and R ³ are preferably a methyl group and an ethyl group, and most preferably a methyl group.

In the general formula (2), X represents O, S or N (R ⁶ ) (R ⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms). Preferably there is. When X is N (R ⁶ ), examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁶ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec-butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-pentyl group And alkyl groups such as neopentyl group, n-hexyl group, 2-methylpentyl group and 3-methylpentyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group, and phenyl group.

  In the general formula (2), the integer of 1 to 20 represented by n is preferably 2 to 5 from the viewpoint of increasing the fluidity of syrup and the polymerization rate of the (meth) acrylic block copolymer (II). .

  The content of the partial structure (1) with respect to all the monomer units forming the (meth) acrylic polymer block (a) is preferably in the range of 0.2 to 100 mol%, and in the range of 0.5 to 50 mol%. Is more preferable, and the range of 1.0 to 20 mol% is more preferable.

  The (meth) acrylic polymer block (a) includes a monomer unit formed by polymerizing a monomer containing a (meth) acrylic acid ester. As such a (meth) acrylic acid ester, a monofunctional (meth) acrylic acid ester having one (meth) acryloyl group and a polyfunctional (meth) acrylic acid ester having two or more (meth) acryloyl groups are used. can do.

  Examples of the monofunctional (meth) acrylic acid ester that can form the (meth) acrylic polymer block (a) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, ( (Meth) acrylic acid isopropyl, (meth) acrylic acid n-butyl, (meth) acrylic acid t-butyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid isobornyl, (meth) Dodecyl acrylate, 2-methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, (meth) acrylic acid 2 -Aminoethyl, N, N-dimethylaminoethyl (meth) acrylate, (meth) acrylate N, N-diethylaminoethyl acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, 2- (trimethylsilyloxy) ethyl (meth) acrylate, 3- (trimethylsilyloxy) propyl (meth) acrylate, ( Glycidyl acrylate, γ-((meth) acryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of (meth) acrylic acid, trifluoromethyl methyl (meth) acrylate, 2-trifluoro (meth) acrylic acid Methylethyl, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, 2-perfluoroethyl (meth) acrylate, permethacrylate (meth) acrylate Fluoromethyl, (meth) acrylic acid diperfluoro Methylmethyl, 2-perfluoromethyl-2-perfluoroethylmethyl (meth) acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, (meth) acrylic acid Examples include 2-perfluorohexadecylethyl. Among these, MMA, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate and other alkyl methacrylates having an alkyl group having 5 or less carbon atoms are preferable, and MMA is the most. preferable.

Moreover, as polyfunctional (meth) acrylic acid ester which can form (meth) acrylic-type polymer block (a), bifunctional (meth) acrylic acid ester (henceforth "di (meta) is shown by following General formula (3)." ) Acrylate (3) ”) is used to carry out living anion polymerization under the conditions described later, whereby one (meth) acryloyloxy group (“ CH ₂ ═C (R ⁵ ) in the following general formula (3) ”is used. (Meth) acryloyloxy group represented by C (O) O ”is selectively polymerized, R ¹ is R ⁴ , R ² is R ^{2 ′} , R ³ is R ^{3 ′} , A (meth) acrylic polymer block (a) having a polymerizable functional group (2) in which X is O is obtained.

（式中、Ｒ^2'およびＲ^3'はそれぞれ独立して炭素数１〜６の炭化水素基を表し、Ｒ⁴およびＲ⁵はそれぞれ独立して水素原子またはメチル基を表し、ｎは１〜２０の整数を表す）

(Wherein R ^{2 ′} and R ^{3 ′} each independently represent a hydrocarbon group having 1 to 6 carbon atoms, R ⁴ and R ⁵ each independently represent a hydrogen atom or a methyl group, and n represents 1 to 1) Represents an integer of 20)

Examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R ^{2 ′} and R ^{3 ′ in} general formula (3) include the same hydrocarbon groups as R ² and R ^{3 in} general formula (2). .
From the viewpoint of increasing the selectivity of polymerization, R ⁴ is preferably a methyl group. From the viewpoint of productivity of di (meth) acrylate (3), R ⁴ and R ⁵ are preferably the same. From the above viewpoints, it is most preferable that R ⁴ and R ⁵ are both methyl groups.

  Specific examples of the di (meth) acrylate (3) include, for example, 1,1-dimethylpropane-1,3-diol di (meth) acrylate, 1,1-dimethylbutane-1,4-diol di (meth) acrylate, 1 , 1-dimethylpentane-1,5-diol di (meth) acrylate, 1,1-dimethylhexane-1,6-diol di (meth) acrylate, 1,1-diethylpropane-1,3-diol di (meth) acrylate, 1,1-diethylbutane-1,4-diol di (meth) acrylate, 1,1-diethylpentane-1,5-diol di (meth) acrylate, 1,1-diethylhexane-1,6-diol di (meth) acrylate 1,1-dimethylpropane-1,3-diol dimethacrylate, 1,1-dimethyl Tan-1,4-diol dimethacrylate, 1,1-dimethylpentane-1,5-diol dimethacrylate, 1,1-dimethylhexane-1,6-diol dimethacrylate, 1,1-diethylpropane-1,3 -Diol dimethacrylate, 1,1-diethylbutane-1,4-diol dimethacrylate, 1,1-diethylpentane-1,5-diol dimethacrylate, and 1,1-diethylhexane-1,6-diol dimethacrylate 1,1-dimethylpropane-1,3-diol dimethacrylate, 1,1-dimethylbutane-1,4-diol dimethacrylate, 1,1-dimethylpentane-1,5-diol dimethacrylate, and 1 1,1-dimethylhexane-1,6-diol dimethacrylate is more preferred Arbitrariness.

These (meth) acrylic acid esters may be used alone or in combination of two or more.
The content of the monomer unit formed from the (meth) acrylic acid ester in the (meth) acrylic polymer block (a) is the total monomer forming the (meth) acrylic polymer block (a). The range of 90-100 mol% is preferable with respect to the unit, the range of 95-100 mol% is more preferable, and 100 mol% may be sufficient. When the (meth) acrylic polymer block (a) contains a monomer unit formed from di (meth) acrylate (3), a single unit formed from di (meth) acrylate (3) is used. The content of the monomer unit is preferably in the range of 0.2 to 100 mol% with respect to all the monomer units forming the (meth) acrylic polymer block (a), and preferably 0.5 to 50 mol%. The range is more preferable, and the range of 1.0 to 20 mol% is more preferable. Furthermore, the total of the content of monomer units formed from MMA and the content of monomer units formed from di (meth) acrylate (3) is the total unit formed from (meth) acrylic acid ester. The range of 80-100 mol% is preferable with respect to a monomer unit, The range of 90-100 mol% is more preferable, The range of 95-100 mol% is further more preferable, 100 mol% may be sufficient.

  The (meth) acrylic polymer block (a) may have a monomer unit formed from a monomer other than the (meth) acrylic acid ester. Examples of the other monomer include α-alkoxy acrylate esters such as methyl α-methoxyacrylate and methyl α-ethoxyacrylate; crotonic acid esters such as methyl crotonate and ethyl crotonate; 3-methoxyacrylic acid. 3-alkoxyacrylic acid esters such as esters; N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and the like ( (Meth) acrylamide; methyl 2-phenylacrylate, ethyl 2-phenylacrylate, n-butyl 2-bromoacrylate, methyl 2-bromomethylacrylate, ethyl 2-bromomethylacrylate, methyl vinyl ketone, ethyl vinyl ketone Methyl isopropenyl ketone And ethyl isopropenyl ketone. These other monomers may be used alone or in combination of two or more.

  The content of the monomer units formed from the other monomers in the (meth) acrylic polymer block (a) is the total monomer forming the (meth) acrylic polymer block (a). The amount is preferably 10 mol% or less, more preferably 5 mol% or less, based on the unit.

  The number average molecular weight (Mn) per (meth) acrylic polymer block (a) is not particularly limited, but from the viewpoint of the fluidity of syrup and the mechanical properties of the resulting methacrylic resin molded product, 500 to 1, The range of 1,000,000 is preferable, and the range of 1,000 to 300,000 is more preferable. In addition, in this specification, Mn and molecular weight distribution mentioned later mean the standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

  The (meth) acrylic polymer block (b) of the (meth) acrylic block copolymer (II) is a monomer formed by polymerizing a monomer containing a (meth) acrylic ester. It is a polymer block consisting of units and having no polymerizable functional group.

In the present specification, the polymerizable functional group means a functional group that exhibits polymerizability upon irradiation with heat, active energy rays or the like. Examples of the polymerizable functional group include ethylenic double bonds such as (meth) acryloyl group, (meth) acryloyloxy group, vinyl group, allyl group, vinyloxy group, 1,3-dienyl group, styryl group (especially general formula A functional group having CH ₂ ═CR— (wherein R is an alkyl group or a hydrogen atom); an epoxy group, an oxetanyl group, a thiol group, a maleimide group, and the like.

  Examples of the (meth) acrylic acid ester that can form the (meth) acrylic polymer block (b) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, (meth) Isopropyl acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, (meth) acrylic acid Dodecyl, trimethoxysilylpropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, (meth) Phenyl acrylate, (meth) acrylic acid naphthyl, (meth) acrylic acid 2- (trimethyl Rushiriruokishi) ethyl include mono (meth) acrylic acid esters such as (meth) acrylic acid 3- (trimethylsilyloxy) propyl. Among them, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, alkyl acrylate having 4 or more carbon atoms such as dodecyl acrylate; 2-ethylhexyl methacrylate, dodecyl methacrylate, etc. A methacrylic acid alkyl ester having an alkyl group having 6 or more carbon atoms is preferred. In addition, these (meth) acrylic acid ester may be used individually by 1 type, or may use 2 or more types together.

  The content of the monomer unit formed by the (meth) acrylic ester in the (meth) acrylic polymer block (b) is the total monomer forming the (meth) acrylic polymer block (b). It is preferably 90 mol% or more, more preferably 95 mol% or more, and may be 100 mol% with respect to the unit.

  The (meth) acrylic polymer block (b) may have a monomer unit formed by a monomer other than the (meth) acrylic acid ester. Examples of the other monomers include α-alkoxy acrylates such as α-methyl acrylate and methyl α-ethoxy acrylate; crotonates such as methyl crotonate and ethyl crotonate; 3-methoxy acrylate. 3-alkoxyacrylic acid esters such as N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, etc. ) Acrylamide; methyl vinyl ketone, ethyl vinyl ketone, methyl isopropenyl ketone, ethyl isopropenyl ketone and the like. These other monomers may be used alone or in combination of two or more.

  The content of the monomer unit formed by the other monomer in the (meth) acrylic polymer block (b) is based on the total monomer units forming the acrylic polymer block (b). 10 mol% or less is preferable, and 5 mol% or less is more preferable.

  Although there is no restriction | limiting in particular in Mn per (meth) acrylic-type polymer block (b), From the point of the handleability of the (meth) acrylic-type block copolymer of this invention, fluidity | liquidity, a mechanical characteristic, etc., 3 It is preferably in the range of 2,000 to 2,000,000, and more preferably in the range of 5,000 to 1,000,000.

  The (meth) acrylic block copolymer (II) is a block in which at least one (meth) acrylic polymer block (a) and at least one (meth) acrylic polymer block (b) are bonded to each other. There are no particular restrictions on the number and order of bonding of each polymer block, but the (meth) acrylic polymer block (a) is a (meth) acrylic block copolymer from the viewpoint of the polymerization rate of syrup. It is preferable to form at least one terminal of (II), and from the viewpoint of ease of production of the (meth) acrylic block copolymer, a linear polymer is more preferable, and one (meta) ) A diblock copolymer in which an acrylic polymer block (a) and one (meth) acrylic polymer block (b) are bonded and / or one (meth) acrylic polymer block. More preferred is a triblock copolymer in which one (meth) acrylic polymer block (a) is bonded to both ends of the pack (b).

  Ratio of mass of (meth) acrylic polymer block (a) composing (meth) acrylic block copolymer (II) to mass of (meth) acrylic polymer block (b) [(meth) acrylic The polymer block (a) :( meth) acrylic polymer block (b)] is not particularly limited, but is preferably 90:10 to 5:95 (mass ratio). When the mass ratio of the (meth) acrylic polymer block (a) to the total mass of the (meth) acrylic polymer block (a) and the (meth) acrylic polymer block (b) is 5% or more ( The polymerization rate of the (meth) acrylic block copolymer (II) is increased, and if it is 90% or less, the toughness of the resulting methacrylic resin molded product is increased, which is preferable.

  In the (meth) acrylic block copolymer (II), the content of the monomer unit formed from the methacrylic acid ester is preferably 5 to 85% by mass, and preferably 7 to 80% by mass. More preferably, it is more preferably 10 to 75% by mass. In the (meth) acrylic block copolymer (II), the content of the monomer unit formed from the acrylate ester is preferably 15 to 95% by mass, and 20 to 93% by mass. It is more preferable that the content is 25 to 90% by mass.

  The Mn of the (meth) acrylic block copolymer (II) is not particularly limited, but is from 4,000 to 3,000 from the viewpoint of the fluidity of the syrup used in the present invention and the mechanical properties of the resulting methacrylic resin molded product. The range of 1,000,000 is preferable, the range of 7,000 to 2,000,000 is more preferable, and the range of 10,000 to 1,000,000 is more preferable.

  The molecular weight distribution of the (meth) acrylic block copolymer (II), that is, the weight average molecular weight / number average molecular weight (Mw / Mn) is preferably in the range of 1.02 to 2.00, 1.05 to 1.80. The range is more preferable, and the range of 1.10 to 1.50 is more preferable.

  The content of the partial structure (1) with respect to all the monomer units forming the (meth) acrylic block copolymer (II) is preferably in the range of 0.1 to 20 mol%, 0.2 to A range of 10 mol% is more preferable, and a range of 0.3 to 5 mol% is more preferable.

  The number of the partial structures (1) contained in the (meth) acrylic block copolymer (II) is preferably 3 or more per polymer molecule from the viewpoint of increasing the polymerization rate, and is 4 or more. It is more preferable that the number is 8 or more.

  The method for producing the (meth) acrylic block copolymer (II) in the present invention is not particularly limited, but an anionic polymerization method or a radical polymerization method is preferable, and a living anion polymerization method or a living radical polymerization method is more preferable from the viewpoint of polymerization control. The living anionic polymerization method is preferable.

  Living radical polymerization methods include a polymerization method using a chain transfer agent such as polysulfide, a polymerization method using a cobalt porphyrin complex, a polymerization method using a nitroxide (see International Publication No. 2004/014926), and a high-cycle heterogeneity such as an organic tellurium compound. Polymerization method using elemental compounds (see Japanese Patent No. 3839829), reversible addition / elimination chain transfer polymerization method (RAFT) (see Japanese Patent No. 3639859), atom transfer radical polymerization method (ATRP) (Japanese Patent No. 3040172) , International Publication No. 2004/013192). Among these living radical polymerization methods, the atom transfer radical polymerization method is preferable, and a metal complex having an organic halide or sulfonyl halide compound as a polymerization initiator and at least one selected from Fe, Ru, Ni, and Cu as a central metal. An atom transfer radical polymerization method using as a catalyst is more preferred.

  Living anionic polymerization methods include a method of living polymerization using an organic rare earth metal complex as a polymerization initiator (see JP 06-93060 A), an alkali metal or alkaline earth metal salt using an organic alkali metal compound as a polymerization initiator, etc. A living anion polymerization in the presence of a mineral acid salt (see JP 05-507737 A), and a living anion polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (Japanese Patent Laid-Open No. Hei 5). 11-335432 and International Publication No. 2013/141105). Among these living anionic polymerization methods, living anionic polymerization is carried out using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound from the viewpoint that the (meth) acrylic polymer block (a) can be directly and efficiently formed. And a living anion polymerization using an organolithium compound as a polymerization initiator in the presence of an organoaluminum compound and a Lewis base is more preferred.

  Examples of the organolithium compound include t-butyllithium, 1,1-dimethylpropyllithium, 1,1-diphenylhexyllithium, 1,1-diphenyl-3-methylpentyllithium, ethyl α-lithioisobutyrate, butyl α-lithioisobutyrate, methyl α-lithioisobutyrate, isopropyl lithium, sec-butyl lithium, 1-methylbutyl lithium, 2-ethylpropyl lithium, 1-methylpentyl lithium, cyclohexyl lithium, diphenylmethyl lithium, α- Examples include methyl benzyl lithium, methyl lithium, n-propyl lithium, n-butyl lithium, n-pentyl lithium and the like. Among them, from the viewpoint of availability and anion polymerization initiating ability, secondary grades such as isopropyl lithium, sec-butyl lithium, 1-methylbutyl lithium, 1-methylpentyl lithium, cyclohexyl lithium, diphenylmethyl lithium, α-methylbenzyl lithium, etc. C3-C40 organolithium compounds having a chemical structure with a carbon atom as an anion center are preferred, and sec-butyllithium is particularly preferred. These organolithium compounds may be used alone or in combination of two or more.

The amount of the organolithium compound used can be determined by the ratio to the amount of monomer used depending on the Mn of the target (meth) acrylic block copolymer (II).
As said organoaluminum compound, the organoaluminum compound shown by the following general formula (A-1) or (A-2) is mentioned.
AlR ⁷ (R ⁸ ) (R ⁹ ) (A-1)
Wherein R ⁷ represents a monovalent saturated hydrocarbon group, monovalent aromatic hydrocarbon group, alkoxy group, aryloxy group or N, N-disubstituted amino group, and R ⁸ and R ⁹ are each independently Or R ⁸ and R ⁹ are bonded to each other to form an aryleneoxy group)
AlR ¹⁰ (R ¹¹ ) (R ¹² ) (A-2)
(Wherein R ¹⁰ represents an aryloxy group, R ¹¹ and R ¹² each independently represent a monovalent saturated hydrocarbon group, a monovalent aromatic hydrocarbon group, an alkoxy group, or an N, N-disubstituted amino group. Represents a group)

In the general formulas (A-1) and (A-2), examples of the aryloxy group that R ⁷ , R ⁸ , R ^9, and R ¹⁰ each independently represent include a phenoxy group, a 2-methylphenoxy group, and 4 -Methylphenoxy group, 2,6-dimethylphenoxy group, 2,4-di-t-butylphenoxy group, 2,6-di-t-butylphenoxy group, 2,6-di-t-butyl-4-methyl Phenoxy group, 2,6-di-t-butyl-4-ethylphenoxy group, 2,6-diphenylphenoxy group, 1-naphthoxy group, 2-naphthoxy group, 9-phenanthryloxy group, 1-pyrenyloxy group, Examples include 7-methoxy-2-naphthoxy group.

In the above general formula (A-1), examples of the aryleneoxy group formed by bonding R ⁸ and R ⁹ to each other include 2,2′-biphenol, 2,2′-methylenebisphenol, 2,2 ′. -Methylenebis (4-methyl-6-tert-butylphenol), (R)-(+)-1,1'-bi-2-naphthol, (S)-(-)-1,1'-bi-2- The functional group which remove | excluded the hydrogen atom of these two phenolic hydroxyl groups in the compound which has two phenolic hydroxyl groups, such as a naphthol, is mentioned.

  In addition, one or more hydrogen atoms contained in the above aryloxy group and aryleneoxy group may be substituted with a substituent. Examples of the substituent include a methoxy group, an ethoxy group, an isopropoxy group, Examples thereof include alkoxy groups such as t-butoxy group; halogen atoms such as chlorine atom and bromine atom.

In the general formulas (A-1) and (A-2), examples of the monovalent saturated hydrocarbon group represented by R ⁷ , R ^11, and R ¹² independently include a methyl group, an ethyl group, and n-propyl. Group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, n-octyl group, 2-ethylhexyl group and other alkyl groups; cyclohexyl group, etc. The monovalent aromatic hydrocarbon group includes, for example, an aryl group such as a phenyl group; the aralkyl group such as a benzyl group; and the alkoxy group includes, for example, a methoxy group and an ethoxy group. , Isopropoxy group, t-butoxy group and the like. Examples of the N, N-disubstituted amino group include dimethylamino group, diethylamino group, diisopropylamino group, and the like. Dialkylamino groups such as bis (trimethylsilyl) amino group and the like. One or more hydrogen atoms contained in the above-described monovalent saturated hydrocarbon group, monovalent aromatic hydrocarbon group, alkoxy group and N, N-disubstituted amino group may be substituted with a substituent. Examples of the substituent include alkoxy groups such as methoxy group, ethoxy group, isopropoxy group and t-butoxy group; halogen atoms such as chlorine atom and bromine atom.

  Examples of the organoaluminum compound (A-1) include ethylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, ethylbis (2,6-di-t-butylphenoxy) aluminum, ethyl [2 , 2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isobutylbis (2,6-di-t) -Butylphenoxy) aluminum, isobutyl [2,2'-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, n-octylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, n-octylbis (2,6-di-t-butylphenoxy) aluminum, n-octyl [2,2′-methyl Bis (4-methyl-6-t-butylphenoxy)] aluminum, methoxybis (2,6-di-t-butyl-4-methylphenoxy) aluminum, methoxybis (2,6-di-t-butylphenoxy) aluminum, Methoxy [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, ethoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, ethoxybis (2,6-di-) t-butylphenoxy) aluminum, ethoxy [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, isopropoxybis (2,6-di-t-butyl-4-methylphenoxy) aluminum , Isopropoxybis (2,6-di-t-butylphenoxy) aluminum, isopropoxy [ 2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, t-butoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, t-butoxybis (2,6- Di-t-butylphenoxy) aluminum, t-butoxy [2,2′-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, tris (2,6-di-t-butyl-4-methylphenoxy) ) Aluminum, tris (2,6-diphenylphenoxy) aluminum and the like. Among them, from the viewpoints of polymerization initiation efficiency, living property of polymerization terminal anion, availability and handling, etc., isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, isobutylbis (2,6 -Di-t-butylphenoxy) aluminum, isobutyl [2,2'-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum and the like are preferable.

  Examples of the organoaluminum compound (A-2) include diethyl (2,6-di-t-butyl-4-methylphenoxy) aluminum, diethyl (2,6-di-t-butylphenoxy) aluminum, diisobutyl (2 , 6-Di-t-butyl-4-methylphenoxy) aluminum, diisobutyl (2,6-di-t-butylphenoxy) aluminum, di-n-octyl (2,6-di-t-butyl-4-methylphenoxy) ) Aluminum, di-n-octyl (2,6-di-t-butylphenoxy) aluminum and the like. These organoaluminum compounds may be used alone or in combination of two or more.

  The amount of the organoaluminum compound used can be appropriately selected in accordance with the type of solvent, other various polymerization conditions, etc., but is generally 1.0 to 10 with respect to 1 mol of the organic lithium compound from the viewpoint of the polymerization rate. It is preferably used in the range of 0.0 mol, more preferably in the range of 1.1 to 5.0 mol, and still more preferably in the range of 1.2 to 4.0 mol. If the amount of the organoaluminum compound used exceeds 10.0 mol with respect to 1 mol of the organolithium compound, it tends to be disadvantageous in terms of economy, and if it is less than 1.0 mol, the polymerization initiation efficiency tends to decrease.

Examples of the Lewis base include compounds having an ether bond and / or a tertiary amine structure in the molecule.
Examples of the compound having an ether bond in the molecule used as the Lewis base include ether. The ether is a cyclic ether having two or more ether bonds in the molecule or an acyclic ether having one or more ether bonds in the molecule from the viewpoint of high polymerization initiation efficiency and living property of the polymerization terminal anion. Is preferred. Examples of the cyclic ether having two or more ether bonds in the molecule include crown ethers such as 12-crown-4, 15-crown-5, and 18-crown-6. Examples of the acyclic ether having one or more ether bonds in the molecule include acyclic monoethers such as dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, and anisole; 1,2-dimethoxyethane, 1,2-diethoxy Ethane, 1,2-diisopropoxyethane, 1,2-dibutoxyethane, 1,2-diphenoxyethane, 1,2-dimethoxypropane, 1,2-diethoxypropane, 1,2-diisopropoxypropane 1,2-dibutoxypropane, 1,2-diphenoxypropane, 1,3-dimethoxypropane, 1,3-diethoxypropane, 1,3-diisopropoxypropane, 1,3-dibutoxypropane, , 3-diphenoxypropane, 1,4-dimethoxybutane, 1,4-diethoxybutane, , 4-diisopropoxybutane, 1,4-dibutoxybutane, 1,4-diphenoxybutane and the like acyclic diethers; diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dibutylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl Ether, dibutylene glycol diethyl ether, triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tributylene glycol dimethyl ether, triethylene glycol diethyl ether, tripropylene glycol diethyl ether, tributylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether Tetrabutylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetrapropylene glycol diethyl ether, acyclic polyethers such as tetramethylammonium butylene glycol diethyl ether. Among these, from the viewpoints of suppressing side reactions and availability, acyclic ether having 1 to 2 ether bonds in the molecule is preferable, and diethyl ether or 1,2-dimethoxyethane is more preferable.

  The compound having a tertiary amine structure in the molecule used as the Lewis base includes tertiary polyamine. A tertiary polyamine means a compound having two or more tertiary amine structures in the molecule. Examples of the tertiary polyamine include N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetraethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyl. Linear polyamines such as diethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetraamine, tris [2- (dimethylamino) ethyl] amine; 1,3,5-trimethylhexahydro-1, 3,5-triazine, 1,4,7-trimethyl-1,4,7-triazacyclononane, 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16 -Non-aromatic heterocyclic compounds such as hexaazacyclooctadecane; aromatic heterocyclic compounds such as 2,2'-bipyridyl and 2,2 ': 6', 2 "-terpyridine .

  A compound having one or more ether bonds and one or more tertiary amine structures in the molecule may be used as the Lewis base. Examples of such a compound include tris [2- (2-methoxyethoxy) ethyl] amine.

These Lewis bases may be used alone or in combination of two or more.
The amount of the Lewis base used is preferably in the range of 0.3 to 5.0 mol with respect to 1 mol of the organic lithium compound from the viewpoints of polymerization initiation efficiency, stability of the polymerization terminal anion, and the like. The range of 3.0 mol is more preferable, and the range of 1.0 to 2.0 mol is more preferable. When the amount of the Lewis base used exceeds 5.0 moles with respect to 1 mole of the organolithium compound, the economy tends to be disadvantageous, and when it is less than 0.3 moles, the polymerization initiation efficiency tends to decrease.

  The amount of Lewis base used is preferably in the range of 0.2 to 1.2 mol, more preferably in the range of 0.3 to 1.0 mol, with respect to 1 mol of the organoaluminum compound. .

  The living anionic polymerization is preferably performed in the presence of an organic solvent from the viewpoint of temperature control and uniformizing the inside of the system to facilitate the polymerization. Organic solvents include hydrocarbons such as toluene, xylene, cyclohexane, and methylcyclohexane from the viewpoints of safety, separability from water in washing of the reaction mixture after polymerization, ease of recovery and reuse, etc .; chloroform, Halogenated hydrocarbons such as methylene chloride and carbon tetrachloride; esters such as dimethyl phthalate are preferred. These organic solvents may be used alone or in combination of two or more. In addition, it is preferable to deaerate the organic solvent in advance in the presence of an inert gas while performing a drying treatment from the viewpoint of allowing the polymerization to proceed smoothly.

  In the living anion polymerization, if necessary, other additives may be present in the reaction system. Examples of the other additives include inorganic salts such as lithium chloride; metal alkoxides such as lithium methoxyethoxy ethoxide and potassium t-butoxide; tetraethylammonium chloride and tetraethylphosphonium bromide.

  The living anionic polymerization is preferably performed at -30 to 25 ° C. When it is lower than −30 ° C., the polymerization rate is lowered and the productivity tends to be lowered. On the other hand, when the temperature is higher than 25 ° C., it tends to be difficult to polymerize the (meth) acrylic polymer block (a) including the partial structure represented by the general formula (1) with good living property.

  The living anionic polymerization is preferably performed in an atmosphere of an inert gas such as nitrogen, argon or helium. Moreover, it is preferable to carry out it under sufficient stirring conditions so that a polymerization reaction system may become uniform. Moreover, it is preferable that the monomer to be used is previously dried in an inert gas atmosphere from the viewpoint of allowing living anion polymerization to proceed smoothly. In the drying treatment, a dehydrating agent or a drying agent such as calcium hydride, molecular sieves, activated alumina or the like is preferably used.

  In the above living anionic polymerization, the organic lithium compound, organoaluminum compound, Lewis base and monomer can be added to the reaction system of the anionic polymerization by contacting the Lewis base with the organoaluminum compound before contacting with the organolithium compound. It is preferable to add so as to. The organoaluminum compound may be added to the anionic polymerization reaction system prior to the monomer or simultaneously. When the organoaluminum compound is added to the anionic polymerization reaction system simultaneously with the monomer, the organoaluminum compound may be added after separately mixing with the monomer.

  The living anionic polymerization can be stopped by adding a polymerization terminator such as methanol; acetic acid or hydrochloric acid in methanol; a protic compound such as aqueous solution of acetic acid or hydrochloric acid to the reaction mixture. The amount of the polymerization terminator used is usually preferably in the range of 1 to 100 mol with respect to 1 mol of the organic lithium compound used.

  As a method for separating and obtaining the (meth) acrylic block copolymer (II) from the reaction mixture after the anionic polymerization is stopped, a known method can be adopted. For example, the reaction mixture is poured into a poor solvent for the (meth) acrylic block copolymer (II) to precipitate the (meth) acrylic block copolymer (II), and the organic solvent is distilled off from the reaction mixture. And a method for obtaining the (meth) acrylic block copolymer (II).

  If the metal component derived from the organolithium compound and organoaluminum compound remains in the (meth) acrylic block copolymer (II) obtained separately, the physical properties of the resulting methacrylic resin molded product will be reduced, and the transparent May cause sexual defects. Therefore, it is preferable to remove the metal component derived from the organolithium compound and the organoaluminum compound after the anionic polymerization is stopped. As a method for removing the metal component, it is effective to perform a washing treatment using an acidic aqueous solution, an adsorption treatment using an adsorbent such as an ion exchange resin, celite, activated carbon or the like. Here, as acidic aqueous solution, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, propionic acid aqueous solution, citric acid aqueous solution etc. can be used, for example.

  As a method for introducing a polymerizable functional group containing the partial structure (1) in the production of the (meth) acrylic block copolymer (II), a monomer containing the above-described di (meth) acrylate (3) In addition to the method of forming a (meth) acrylic polymer block (a) by polymerizing a polymer, a polymer containing a partial structure (hereinafter referred to as “precursor structure”) serving as a precursor of the partial structure (1) A method of converting the precursor structure into the partial structure (1) after forming the block is also mentioned. A polymer block containing a precursor structure can be obtained by polymerizing a monomer containing a polymerizable functional group and a compound containing a precursor structure. Examples of the polymerizable functional group include a styryl group, a 1,3-dienyl group, a vinyloxy group, a (meth) acryloyl group, and a (meth) acryloyl group is preferable. The precursor structure includes a hydroxyl group protected by a hydroxyl group and a protecting group (silyloxy group, acyloxy group, alkoxy group, etc.), an amino group and an amino group protected by a protecting group (carbamate group, amide group, etc.), a thiol group, and the like. Examples thereof include a thiol group protected by a protecting group (thioether group, thioester group, etc.), an isocyanate group, and the like.

  A polymer block containing a hydroxyl group as a precursor structure is reacted with a compound having a partial structure (1) and a partial structure (carboxyl group, ester, carbonyl halide, etc.) capable of reacting with a hydroxyl group, thereby forming a (meth) acrylic polymer. Block (a) can be formed. Further, a polymer block containing a hydroxyl group protected by a protecting group as a precursor structure can form a (meth) acrylic polymer block (a) in the same manner after removing the protecting group to form a hydroxyl group.

  A polymer block containing an amino group as a precursor structure is a compound having a partial structure (1) and a partial structure capable of reacting with a hydroxyl group (carboxyl group, carboxylic anhydride, ester, carbonyl halide, aldehyde group, isocyanate group, etc.) By reacting with (meth) acrylic polymer block (a). A polymer block containing an amino group protected by a protecting group as a precursor structure can form a (meth) acrylic polymer block (a) in the same manner after removing the protecting group to form an amino group.

  The polymer block containing a thiol group as a precursor structure comprises a partial structure (1) and a partial structure capable of reacting with a thiol group (carboxyl group, carboxylic acid anhydride, ester, carbonyl halide, isocyanate group, carbon-carbon double bond) Etc.) can be reacted with a compound having (meth) acrylic polymer block (a). A polymer block containing a thiol group protected by a protective group as a precursor structure can form a (meth) acrylic polymer block (a) in the same manner after removing the protective group to form a thiol group.

  A polymer block containing an isocyanate group as a precursor structure is reacted with a compound having a partial structure (1) and a partial structure (hydroxyl group, amino group, etc.) capable of reacting with an isocyanate group, to form a (meth) acrylic polymer block. (A) can be formed.

  In the production of the (meth) acrylic block copolymer (II), as a method of forming the (meth) acrylic polymer block (a), from the viewpoint that the polymerizable functional group (2) can be easily introduced directly, A method of polymerizing a monomer containing di (meth) acrylate (3), typically a method of living anion polymerization is preferred.

  The syrup used for the production of the methacrylic resin molded product of the present invention contains a polymerization initiator (III). The content of the polymerization initiator (III) in the syrup is 0 with respect to 100 parts by mass of the polymerizable component (total of unsaturated monomer (I) and (meth) acrylic block copolymer (II)). The range of 0.01-5 mass parts is preferable, and the range of 0.025-2 mass parts is more preferable. In addition, when using 2 or more types of polymerization initiators (III) together, content of the said polymerization initiator (III) means a total amount.

Examples of the polymerization initiator (III) include a thermal polymerization initiator and a photopolymerization initiator that initiates polymerization by active energy rays, and a thermal polymerization initiator is preferable from the viewpoint of simplicity of equipment.
The thermal polymerization initiator is not particularly limited, but may be an azo initiator [for example, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (VAZO33, etc.), 2,2′-azobis (2-amidino Propane) dihydrochloride (DuPont Chemical, VAZO50, etc.), 2,2'-azobis (2,4-dimethylvaleronitrile) (DuPont Chemical, VAZO52, etc.), 2,2'-azobisisobutyronitrile ( DuPont Chemical, VAZO64, etc.), 2,2′-azobis-2-methylbutyronitrile (DuPont Chemical, VAZO67, etc.), 1,1-azobis (1-cyclohexanecarbonitrile) (DuPont Chemical, VAZO88, etc.) 2,2'-azobis (2- Chloropropylpropionitrile), 2,2'-azobis (methylisobutyrate) (manufactured by Wako Pure Chemical Industries, Ltd., V-601, etc.), peroxides [benzoyl peroxide, acetyl peroxide, lauroyl peroxide, peroxide Decanoyl oxide, dicetyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate (manufactured by Akzo Nobel, Perkadox 16S, etc.), di (2-ethylhexyl) peroxydicarbonate, t-butyl peroxypi Valate (manufactured by Elf Atochem, Lupersol 11, etc.), t-butylperoxy-2-ethylhexanoate (manufactured by Akzo Nobel, Trigonox 21-C50, etc.), cumene hydroperoxide, dicumyl peroxide, etc.], persulfate Salt (potassium persulfate, sodium persulfate Potassium, ammonium persulfate, etc.), pinacol compound (tetraphenyl 1,1,2,2-ethanediol and the like) and the like, azo initiators, peroxides, and persulfates are preferable.

Of these, azo initiators, peroxides, and persulfates are preferable. These thermal polymerization initiators may be used alone or in combination of two or more.
As photopolymerization initiators, acetophenones (for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1- ON, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, etc.), benzophenones (for example, benzophenone, benzoylbenzoic acid, hydroxybenzophenone, 3,3′-dimethyl-4-methoxy) Carbonyl compounds such as benzophenone, acrylated benzophenone), Michler ketones (eg, Michler ketone) and benzoins (eg, benzoin, benzoin methyl ether, benzoin isopropyl ether); tetramethylthiuram monosulfide, thioxanthone Compounds (eg, thioxanthone, 2-chlorothioxanthone, etc.); acylphosphine oxides (eg, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl)) -Phosphorus compounds such as phenylphosphine oxide; titanocenes (for example, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-) Radical polymerization initiators such as titanium compounds such as yl) -phenyl) titanium and the like. Of these, acetophenones and benzophenones are preferable. These photopolymerization initiators may be used alone or in combination of two or more.

  Moreover, when the said syrup contains a photoinitiator, this syrup may contain a sensitizer further. Examples of the sensitizer include n-butylamine, di-n-butylamine, tri-n-butylphosphine, allylthiouric acid, triethylamine, diethylaminoethyl methacrylate and the like. Of these, diethylaminoethyl methacrylate and triethylamine are preferable.

  When a photopolymerization initiator and a sensitizer are mixed and used, the mass ratio of the photopolymerization initiator and the sensitizer is preferably in the range of 10:90 to 90:10, and 20:80 to 80: A range of 20 is more preferred.

  The syrup used in the present invention may contain a reducing agent. By using a reducing agent in the syrup, the amount of the polymerization initiator (III) used can be reduced. The preferred reducing agent depends on the polymerization initiator (III) to be used, but the preferred combination of the polymerization initiator (III) and the reducing agent includes the above-mentioned persulfate initiator, sodium metabisulfite and sodium bisulfite. Combinations with reducing agents; combinations of the above peroxide initiators (benzoyl peroxide, etc.) with tertiary amines (dimethylaniline, etc.), organic hydroperoxides (dicumyl peroxide, etc.) and organometallic compounds (cobalt naphthate) Etc.) and the like.

  The syrup may contain a known chain transfer agent in order to adjust the molecular weight. Examples of the chain transfer agent include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate). Mercaptans such as (Rate) are preferably used. These chain transfer agents may be used alone or in combination of two or more. A chain transfer agent can be normally used in 0.01-0.5 mass% with respect to the said polymeric component.

  In addition, the syrup is made of other organic and inorganic pigments for the purpose of imparting design properties, such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcium silicate, calcium sulfate, barium sulfate, silica powder, talc, clay, and alumina. Inorganic fillers such as ceramic particles, mica (mincite), pulverized minerals such as sandstone; flame retardants, UV absorbers, reinforcing materials, internal mold release agents, thickeners, low shrinkage agents, water repellents, compatibilization You may contain an agent etc. as needed.

  As said inorganic filler, the inorganic filler which has hydroxyl groups, such as aluminum hydroxide and magnesium hydroxide, is preferable, and it may coat | cover the surface beforehand using a silane coupling agent as needed.

[Method for producing methacrylic resin molded product]
According to the production method of the present invention, a syrup containing a polymerizable component comprising an unsaturated monomer (I) and a (meth) acrylic block copolymer (II) and a polymerization initiator (III) is used as a mold. By injection and polymerization (cast polymerization method), a methacrylic resin molded product is obtained.

  Specifically, after preparing a syrup by mixing a polymerization initiator (III) with a polymerizable component in which a (meth) acrylic block copolymer (II) is dissolved in an unsaturated monomer (I) The syrup is composed of a mold (for example, two plates arranged with a gap between them in parallel, a sealing material positioned along the periphery of the plate in the gap between the two plates, a clamp for holding them, etc. A methacrylic resin molded product can be produced by polymerization in a state enclosed in a mold.

  The material of the mold is not limited, but glass or metal (stainless steel, etc.) is usually used in consideration of smoothness, heat resistance, peelability from the resulting methacrylic resin molded product, etc. Glass is preferred when polymerizing.

  The inner dimension of the mold is determined by the size and shape of the desired methacrylic resin molded body, and is not particularly limited. For example, when producing a plate-like methacrylic resin molded body, the thickness is generally in the range of 1 mm to 20 mm. Set to

  When the syrup contains a thermal polymerization initiator, polymerization of the polymerizable component in the syrup is usually initiated by heating the mold. If the removal of reaction heat accompanying polymerization is insufficient or if there is uneven heat accumulation, the resulting methacrylic resin molded product may cause defects on the surface or foam inside. In general, circulating hot water or circulating hot air is applied as a heat medium.

  The polymerization temperature is determined depending on the conditions for polymerization by heating, the polymerization initiator (III) to be used, the type and amount of the chain transfer agent, the composition of the monomer mixture, the size of the desired methacrylic resin molded product, etc. Is usually from 30 to 140 ° C., and the polymerization time is usually from 2 to 35 hours. Such polymerization temperature may be changed during the process. For example, after polymerization at 30 to 80 ° C. for 1 to 30 hours, performing polymerization at 110 to 140 ° C. for 1 to 5 hours does not leave the unpolymerized unsaturated monomer (I) causing poor appearance To preferred.

  When the syrup contains a photopolymerization initiator, the polymerizable component in the syrup can be polymerized by irradiation with active energy rays. As such active energy rays, light rays, electromagnetic waves, particle rays, and combinations thereof can be used. However, ultraviolet rays or electron beams are preferable, and ultraviolet rays are more preferable from the viewpoint of polymerization rate, availability of an irradiation apparatus, price, and the like.

  The active energy ray to be irradiated can be irradiated using a known apparatus. In the case of an electron beam (EB), an acceleration voltage of 0.1 to 10 MeV and an irradiation dose of 1 to 500 kGy are appropriate.

For the ultraviolet irradiation, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an LED, or the like that emits light having a wavelength range of 150 to 450 nm can be used. Integrated light quantity of active energy rays, usually in the range of 10~20000mJ / cm ^2, the range of 30~5000mJ / cm ² is preferred. If the amount is less than 10 mJ / cm ^2, the polymerization rate of syrup tends to decrease, and if it is more than 20000 mJ / cm ² , the resulting methacrylic resin molded product may be colored.

The relative humidity when irradiating active energy rays to the syrup is preferably 30% or less, and more preferably 10% or less, from the viewpoint of suppressing decomposition of syrup.
After the polymerization is completed, the mold can be removed to obtain a methacrylic resin molded product.

  The methacrylic resin molded product obtained by the present invention has excellent high-temperature creep characteristics and impact resistance, and also has excellent weather resistance unique to methacrylic resin. Can be used in various fields as decorative materials, lighting covers, artificial marble, automobile parts, glazing materials and the like. In addition, since it has appropriate flexibility and does not use environmental hormone substances such as bisphenol A, it should preferably be used for food production applications (such as moss stretchers) that undergo boiling sterilization or UV sterilization. Can do.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to this Example. In the following Examples and Comparative Examples, the raw materials were dried and purified by a conventional method and degassed with nitrogen, and the transfer and supply were performed under a nitrogen atmosphere.

  In the following synthesis examples 1 to 3, the (meth) acrylic block copolymers (II-1) and (II-2) having a polymerizable functional group used in the following examples and the crosslinked rubber used in the comparative example Particles (G) were synthesized using chemicals dried and purified by a conventional method.

In the following synthesis examples 1 and 2, the obtained polymer was subjected to GPC (gel permeation chromatography) measurement, and the number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw) in terms of standard polystyrene / Mn).
Equipment: GPC equipment "HLC-8220GPC" manufactured by Tosoh Corporation
Separation column: “TSKgel SuperMultipore HZ-M (column diameter = 4.6 mm, column length = 15 cm)” manufactured by Tosoh Corporation
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 ml / min Column temperature: 40 ° C
Detection method: differential refractive index (RI)

In the (meth) acrylic block copolymer (II) obtained in Synthesis Examples 1 and 2 below,
(Meth) content of content and (meth) partial structure for the monomer units forming the acrylic polymer block (a) (1) of the acrylic polymer block (a), ¹ H at the following conditions -NMR measurement was performed and calculated from the ratio of the integral values.
¹ H-NMR measurement condition apparatus: nuclear magnetic resonance apparatus “JNM-ECX400” manufactured by JEOL Ltd.
Solvent: Deuterated chloroform Temperature: 25 ° C
The average dispersed particle size of the emulsion obtained in Synthesis Example 3 below was measured by a dynamic light scattering method at a measurement temperature of 26 ° C. using a particle size measuring device (manufactured by Otsuka Electronics Co., Ltd., FPAR-1000).

[Synthesis Example 1]
After 1.5L of toluene was added to a 3L flask which had been dried and purged with nitrogen, 1,1,4,7,10,10-hexamethyltriethylene was added as a Lewis base while stirring the solution in the flask. 1.9 ml (6.8 mmol) of tetramine and 20.9 ml (9.4 mmol) of a 0.450 mol / L toluene solution of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as the organoaluminum compound. After adding sequentially, it cooled to -20 degreeC. To this was added 5 ml (6.5 mmol) of a 1.30 mol / L cyclohexane solution of sec-butyllithium as an organolithium compound, and 6.2 ml (26 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate as a monomer. ) And 138.3 ml of MMA 132.1 ml (1.24 mol) were added all at once to initiate anionic polymerization. After stirring for 300 minutes from the end of the addition of the above mixture, the reaction solution changed from the original yellow color to colorless.

  Subsequently, while stirring the reaction solution at −20 ° C., 11.6 ml (5%) of a 0.450 mol / L toluene solution of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as the organoaluminum compound was used. .2 mmol), and 1 minute later, 273.3 ml (1.90 mol) of n-butyl acrylate as a monomer was added dropwise over 2 hours and stirred for 5 minutes.

  Next, 129.4 ml of a mixture of 5.9 ml (24.5 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate and 123.5 ml (1.16 mol) of MMA was added as a monomer, and then 2 The temperature was raised to 20 ° C at a rate of ° C / min. After stirring for 720 minutes from the addition of the above mixture, 100 ml of methanol was added to stop anionic polymerization. The obtained solution was poured into 10 L of methanol, the polymer was precipitated, recovered by filtration, dried at 100 ° C. and 30 Pa, and dried with 447 g of (meth) acrylic block copolymer (II) (hereinafter “(meta ) Acrylic block copolymer (II-1) ”). Mn of the obtained (meth) acrylic block copolymer (II-1) was 80,900, and Mw / Mn was 1.34. In addition, the content of the (meth) acrylic polymer block (a) in the (meth) acrylic block copolymer (II-1) is 52% by mass, forming the (meth) acrylic polymer block (a). The content of the partial structure (1) with respect to the monomer unit to be 2.1 mol%.

[Synthesis Example 2]
After 1.5L of toluene was added to a 3L flask which had been dried and purged with nitrogen, 1,1,4,7,10,10-hexamethyltriethylene was added as a Lewis base while stirring the solution in the flask. 1.1 ml (4.1 mmol) of tetramine and 12.6 ml (5.7 mmol) of a 0.450 mol / L toluene solution of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound. After adding sequentially, it cooled to -20 degreeC. To this was added 3 ml (3.9 mmol) of a 1.30 mol / L cyclohexane solution of sec-butyllithium as an organolithium compound, and 3.7 ml of 1,1-dimethylpropane-1,3-diol dimethacrylate as a monomer (15 .6 mmol) and 165.4 ml of MMA 161.7 ml (1.52 mol) were added all at once to initiate anionic polymerization. After stirring for 600 minutes from the end of the addition of the mixture, the reaction solution changed from the original yellow color to colorless.

  Subsequently, while stirring the reaction solution at −20 ° C., 6.9 ml (3%) of a 0.450 mol / L toluene solution of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum as an organoaluminum compound was obtained. 1 mmol), and 1 minute later, 326.5 ml (2.27 mol) of n-butyl acrylate as a monomer was added dropwise over 2 hours, followed by stirring for 5 minutes.

  Next, 7.4 ml of a mixture of 3.5 ml (14.7 mmol) of 1,1-dimethylpropane-1,3-diol dimethacrylate and 3.9 ml (36.8 mmol) of MMA was added as a monomer, and then 2 The temperature was raised to 20 ° C at a rate of ° C / min. After stirring for 180 minutes, 100 ml of methanol was added to stop anionic polymerization. The obtained solution was poured into 10 L of methanol, the polymer was precipitated, recovered by filtration, dried at 100 ° C. and 30 Pa, and 420 g of (meth) acrylic block copolymer (II) (hereinafter “(meta ) Acrylic block copolymer (II-2) ”) was obtained. Mn of the obtained (meth) acrylic block copolymer (II-2) was 122,500, and Mw / Mn was 1.39. In addition, the content of the (meth) acrylic polymer block (a) in the (meth) acrylic block copolymer (II-2) is 36% by mass, forming the (meth) acrylic polymer block (a). The content of the partial structure (1) with respect to the monomer unit to be obtained was 1.9 mol%.

[Synthesis Example 3]
(1) Into a glass-lined reaction tank (100 liters) equipped with a condenser, thermometer and stirrer, 48 kg of ion-exchanged water is added, and then 416 g of sodium stearate, 128 g of sodium lauryl sarcosinate and 16 g of sodium carbonate Was added and dissolved. Next, 11.2 kg of MMA and 110 g of allyl methacrylate were added, and the temperature was raised to 80 ° C. while stirring. Then, 560 g of a 2% potassium persulfate aqueous solution was added to initiate polymerization, and the emulsion was polymerized at 80 ° C. for 5 hours. Obtained.

  (2) Next, after further adding 720 g of a 2% aqueous sodium persulfate solution to the emulsion obtained in (1) above, a monomer comprising 12.4 kg of butyl acrylate, 1.76 kg of styrene and 280 g of allyl methacrylate The mixture was added dropwise over 60 minutes, and then stirring was continued for 60 minutes for graft polymerization.

  (3) To the emulsion after graft polymerization obtained in (2) above, 320 g of a 2% aqueous potassium persulfate solution is added, and further a single amount comprising 6.2 kg of MMA, 0.2 kg of methyl acrylate and 200 g of n-octyl mercaptan The mixture was added over 30 minutes, and then stirring was continued for 60 minutes to complete the polymerization, followed by cooling to an emulsion in which the multilayer structure polymer particles (three-stage polymer) were dispersed (hereinafter referred to as “emulsion (e-1)”. ) "). The emulsion (e-1) obtained had an average dispersed particle diameter of 0.23 μm and a solid content concentration of 40%.

  (4) Using the same reaction tank as used in (1) above, 48 kg of ion-exchanged water was added, and then 252 g of a surfactant (“PEREX SS-H” manufactured by Kao Corporation) was added and stirred. And dissolved. After raising the temperature to 70 ° C., 160 g of 2% aqueous potassium persulfate solution was added, and then a mixture consisting of 3.04 kg of MMA, 0.16 kg of methyl acrylate and 15.2 g of n-octyl mercaptan was added all at once to initiate polymerization. It was. Stirring was continued for 30 minutes from the end of the exothermic polymerization, 160 g of 2% aqueous potassium persulfate solution was added, and then a mixture consisting of 27.4 kg of MMA, 1.44 kg of methyl acrylate and 98 g of n-octyl mercaptan was added for 2 hours. The polymerization was carried out by dripping continuously. After completion of dropping, the mixture was allowed to stand for 60 minutes and then cooled to obtain an emulsion in which (meth) acrylic ester polymer particles were dispersed (hereinafter referred to as “emulsion (e-2)”). The emulsion (e-2) obtained had an average dispersed particle diameter of 0.12 μm and a solid content concentration of 40%. The intrinsic viscosity of the (meth) acrylic acid ester polymer particles in the emulsion (e-2) was 0.44 g / dl.

  (5) The emulsion (e-1) obtained in the above (3) and the emulsion emulsion (e-2) obtained in the above (4) are converted into multilayer structure polymer particles in the emulsion (e-1): emulsion After mixing so that the mass ratio of the (meth) acrylic acid ester polymer particles in (e-2) was 2: 1, the mixture was frozen at −20 ° C. for 2 hours. Next, the frozen emulsion mixture was poured into 2 times mass 80 ° C. warm water and stirred at 80 ° C. for 20 minutes to obtain a slurry. The solid content recovered from the slurry by filtration was dried at 70 ° C. to obtain powdered crosslinked rubber particles (referred to as “crosslinked rubber particles (G)”).

<Performance evaluation test method>
(Total light transmittance)
Using a test piece having a length of 5 cm, a width of 5 cm, and a thickness of 3.0 mm prepared in Examples and Comparative Examples, using a haze meter (manufactured by Murakami Color Research Laboratory, HM-150) according to JIS K7361-1. The total light transmittance was measured at 23 ° C.

(Charpy impact test (no notch))
The Charpy impact strength of a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 3.0 mm without notch is 23 ° C. using a digital impact tester (manufactured by Toyo Seiki, DG-CB) in accordance with ISO 179-1eU. Measured.

(Haze)
The haze value was measured using a haze meter (manufactured by Murakami Color Research Laboratory, HM-150) in accordance with JIS K7136.

  First, the haze value at 23 ° C. of a test piece having a length of 5 cm, a width of 5 cm, and a thickness of 3.0 mm prepared in Examples and Comparative Examples was measured. Subsequently, after leaving this test piece for 30 minutes in a 70 degreeC thermostat, the test piece was taken out and the haze value was measured again immediately and it was set as the haze value in 70 degreeC.

(Presence or absence of whitening due to stretching)
A test piece having a length of 80 mm, a width of 10 mm, and a thickness of 3.0 mm was stretched at 140 ° C. at 0.5 mm / min by a tensile tester (Autograph AG-2000B (manufactured by Shimadzu Corporation)), and the state of the test piece was observed. The results were evaluated according to the following criteria.
○: There is no cloudiness until the methacrylic resin plate breaks.
X: It becomes cloudy before the methacrylic resin plate breaks.

[Example 1]
91 parts by mass of MMA (manufactured by Kuraray Co., Ltd.), 9 parts by mass of (meth) acrylic block copolymer (II-1) obtained by the method of Synthesis Example 1, and 0.25 mass as the polymerization initiator (III) A portion of 2,2′-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) was mixed and deaerated at 650 mmHg (87 kPa) for 30 minutes to obtain syrup. Such syrup is poured into a glass cell composed of two water-repellent treated glass plates (thickness 10 mm, 30 cm square) and a vinyl chloride resin gasket, and at 72 ° C. for 6 hours and then at 120 ° C. for 2 hours. Then, polymerization was performed in a hot-air circulating furnace to prepare a sheet-like methacrylic resin molded body (methacrylic resin plate) having a thickness of 3.0 mm. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Example 2]
The same procedure as in Example 1 was conducted except that the (meth) acrylic block copolymer (II-2) synthesized in Synthesis Example 2 was used instead of the (meth) acrylic block copolymer (II-1). A methacrylic resin plate having a thickness of 3.0 mm was produced. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Example 3]
82 parts by mass of MMA (manufactured by Kuraray Co., Ltd.), 18 parts by mass of (meth) acrylic block copolymer (II-1), 0.35 parts by mass of 2,2′-azobisisobutyronitrile (Wako Pure) A methacrylic resin plate having a thickness of 3.0 mm was produced in the same manner as in Example 1 except that (made by medicine) was used. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Example 4]
90 parts by mass of MMA (manufactured by Kuraray Co., Ltd.), 10 parts by mass of (meth) acrylic block copolymer (II-1) and 0.27 parts by mass of t-butylperoxyisopropyl monocarbonate as polymerization initiator (III) (Nippon Yushi Co., Ltd .: Product name Perbutyl I) was mixed and degassed at 650 mmHg (87 kPa) for 30 minutes to obtain syrup. Such syrup is poured into a glass cell composed of two water-repellent treated glass plates (thickness 10 mm, 30 cm square) and a vinyl chloride resin gasket, and at 85 ° C. for 6 hours and then at 120 ° C. for 2 hours. Then, polymerization was performed in a hot air circulating furnace to produce a methacrylic resin plate having a thickness of 3.0 mm. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Comparative Example 1]
100 parts by mass of MMA (manufactured by Kuraray Co., Ltd.) and 0.15 parts by mass of 2,2′-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, deaerated at 650 mmHg (87 kPa) for 30 minutes, I got syrup. Such syrup is poured into a glass cell composed of two water-repellent treated glass plates (thickness 10 mm, 30 cm square) and a vinyl chloride resin gasket, and at 72 ° C. for 6 hours and then at 120 ° C. for 2 hours. Then, polymerization was carried out in a hot air circulating furnace to prepare a methacrylic resin plate having a thickness of 3.0 mm. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Comparative Example 2]
Bead-like methacrylic resin obtained by suspension polymerization of a monomer mixture of MMA / methyl acrylate = 99.3 / 0.7 (mass ratio) (weight average molecular weight 89,000, molecular weight distribution 1.85, The polymer composition was mixed with 70 parts by mass of “methacrylic resin (P)” using a supermixer at a ratio of 30 parts by mass of the crosslinked rubber particles (G) obtained in Synthesis Example 3. Prepared. The obtained polymer composition was hot press molded at 230 ° C. to prepare a methacrylic resin plate having a thickness of 3.0 mm. A test piece was cut out from the obtained methacrylic resin plate and evaluated for total light transmittance, haze (23 ° C., 70 ° C.), Charpy impact strength (no notch), and stretch whitening property. The evaluation results are shown in Table 1.

[Comparative Example 3]
70 parts by mass of MMA (manufactured by Kuraray Co., Ltd.) and 30 parts by mass of crosslinked rubber particles (G) and 0.25 parts by mass of 2,2′-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries) were mixed. And 650 mmHg (87 kPa) for 30 minutes to obtain syrup. Such syrup is poured into a glass cell composed of two water-repellent treated glass plates (thickness 10 mm, 30 cm square) and a vinyl chloride resin gasket, and at 72 ° C. for 6 hours and then at 120 ° C. for 2 hours. Then, polymerization was carried out in a hot air circulating furnace to prepare a methacrylic resin plate having a thickness of 3.0 mm. The obtained methacrylic resin plate was not evaluated because the crosslinked rubber particles (G) were settled and separated during the polymerization, and the uniformity was extremely inferior.

表１に示すように、本発明の製造方法で得られるメタクリル樹脂成形体は高い全光線透過率を示す。また、比較例２と比較して７０℃におけるヘイズ値が小さく加熱による白化が少ない。また、耐衝撃性に優れ、かつ延伸に伴う白化がない。

As shown in Table 1, the methacrylic resin molded product obtained by the production method of the present invention exhibits high total light transmittance. Further, compared with Comparative Example 2, the haze value at 70 ° C. is small, and whitening due to heating is small. Moreover, it is excellent in impact resistance and has no whitening due to stretching.

Claims (3)

(Meth) acrylic polymer block having 70 to 99% by mass of unsaturated monomer (I) containing methyl methacrylate and a polymerizable functional group containing partial structure (1) represented by the following general formula (1) 1 to 30% by mass of (meth) acrylic block copolymer (II) comprising (a) and (meth) acrylic polymer block (b) having no polymerizable functional group (however, the unsaturated unit A polymerizable component consisting of a monomer (I) and a (meth) acrylic block copolymer (II) occupies 100% by mass in total) and a syrup containing a polymerization initiator (III) are injected into a mold. A process for producing a methacrylic resin molded body comprising a step of polymerizing.

(Wherein R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms) The method for producing a methacrylic resin molded article according to claim 1, wherein the polymerizable functional group is represented by the following general formula (2).

(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, R ² and R ³ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and X represents O, S, or N (R ⁶ ) (R ⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms), and n represents an integer of 1 to 20)   A methacrylic resin molded product obtained by the production method according to claim 1.