JP6761301B2 - Methacrylic resin and methacrylic resin composition - Google Patents

Description

The present invention relates to an improved methacrylic resin, a methacrylic resin composition containing the same, and the like.

In recent years, with the expansion of the flat panel display market such as liquid crystal displays, plasma displays, and organic EL displays, and the optical lens market such as optical lenses for mobile terminals and pickup lenses for DVD / BlueRayDisc, the demand for clearer images has increased. Therefore, there is a demand for an optical material having more advanced optical characteristics in addition to transparency, heat resistance, and strength.

As the optical material, an acrylic resin ((meth) acrylic acid ester polymer) has been attracting attention from the viewpoint of transparency, surface hardness, optical properties and the like.
Conventionally, among acrylic resins, in particular, glutaric anhydride (see, for example, Patent Document 1), maleic anhydride (see, for example, Patent Document 2) and the like are copolymerized with a (meth) acrylic acid ester monomer. It has been reported that the acrylic resin having improved heat resistance is excellent as an optical material.

However, the acrylic resin having improved heat resistance as described above (heat-resistant acrylic resin) is caused by a ring structure or the like as compared with a general-purpose acrylic resin, that is, a copolymer of methyl methacrylate and an acrylic acid ester. There are drawbacks such as coloring by absorption of visible light and easy thermal decomposition in high temperature molding.
Further, as the molded product becomes larger and thinner (film formation, etc.), the molding at a high temperature and the residence time at a high temperature become longer, so that there is a drawback that silver streaks and foaming may occur during the molding process.
In addition, molding at a high temperature has a problem that strong coloring occurs due to an increase in oxidation / unsaturated bonds. Further, since the heat-resistant acrylic resin has low strength and low toughness, it has a problem that the productivity is inferior in terms of film molding processability and handleability.

Conventionally, as a technique for improving the strength of a heat-resistant acrylic resin, a technique for incorporating a crosslinked elastic body having a multilayer structure into an acrylic resin containing a glutaric anhydride-based unit has been disclosed (for example, Patent Documents). 3).
Further, a technique for adding acrylic rubber to an acrylic resin containing a maleic anhydride unit is disclosed (see, for example, Patent Document 4).
Furthermore, a technique for adding a multilayer rubber and a heat stabilizer to an acrylic resin containing a maleic anhydride unit (see, for example, Patent Document 5) and an acrylic resin containing a structural unit having a ring structure in the main chain. A technique for incorporating a rubber polymer and, if necessary, an ultraviolet absorber into a resin is disclosed (see, for example, Patent Document 6).

Conventionally, as a technique for improving the coloring of a heat-resistant acrylic resin, a monomer component containing an N-substituted maleimide (a) and a methacrylic acid ester (b) in order to reduce the amount of a coloring cyclic monomer in the visible light region. By controlling the supply amount of the methacrylic acid ester (b) so that the proportion of the N-substituted maleimide (a) in the mixture is reduced, the amount of the residual N-substituted maleimide monomer is reduced, the transparency is excellent, and the coloring is low. We have proposed a method for obtaining a heat-resistant methacrylic resin (see, for example, Patent Document 7).
Further, in a methacrylic acid ester-based monomer / maleimides monomer polymerization system using a sulfur-based chain transfer agent such as mercaptan, by allowing an acidic substance to exist in the reaction system, the residual maleimides monomer and molding can be performed. A method has been proposed in which maleimides monomers generated by heating during processing or the like are reduced to suppress coloring (see, for example, Patent Document 8).

Japanese Unexamined Patent Publication No. 2006-241197 Japanese Unexamined Patent Publication No. 03-023404 Japanese Unexamined Patent Publication No. 2000-178399 Japanese Unexamined Patent Publication No. 05-119217 JP-A-2010-126550 Japanese Unexamined Patent Publication No. 2014-098117 Japanese Unexamined Patent Publication No. 9-324016 Japanese Unexamined Patent Publication No. 2001-233919

However, the acrylic resins disclosed in Patent Documents 1 and 2 are insufficient in moisture resistance and thermal stability, and the acrylic resin compositions disclosed in Patent Documents 3 and 4 are not sufficient. Has problems that the heat resistance is lowered by the addition of the rubbery component, the thermal stability is further deteriorated, and foaming and foreign matter are likely to occur.
The acrylic resin or acrylic resin composition disclosed in References 1 to 4 is particularly excellent in that acrylic resin originally has excellent heat deterioration, resin decomposition, generation of foreign matter, etc. during film molding. It has a problem that it cannot fully exhibit its optical characteristics.

Further, in the technique disclosed in Patent Document 5, by adding a heat stabilizer, it is possible to impart excellent mechanical strength and molding stability while imparting a certain degree of high heat resistance. There is. However, the addition of the heat stabilizer tends to deteriorate the color tone, and there is a problem that the heat stabilizer may bleed out during the molding process, which may cause molding defects.

From the viewpoint of coloring, in recent years, the application has been expanded from the optical film application to the thick molded body application such as a lens and a molded plate. Moreover, the provision of a resin capable of exhibiting high transparency is eagerly desired.
Therefore, it is necessary to suppress coloring to a higher degree than before, and it has been found that the methods such as Patent Documents 2 and 3 are insufficient as a methacrylic resin used for molded articles having a long optical path length. It was.

In view of the above-mentioned problems of the prior art, in the present invention, a methacrylic resin having excellent heat resistance, thermal stability, color tone, and moldability, a methacrylic resin composition containing the same, and a front of a display containing the same. It is an object of the present invention to provide a face plate, an optical lens, a light guide plate, an instrument panel, and an in-vehicle center console.

The present inventors have completed the present invention as a result of repeated diligent research in order to solve the above-mentioned problems of the prior art.
That is, the present invention is as follows.

（式（１）中、Ｒ^１は、炭素数が１〜６の置換若しくは非置換のアルキル基を表し、Ｒ^２は炭素数が１〜３の基を表す。）
主鎖に環構造を有する構造単位（Ｂ）：３〜３０質量％と、
下記一般式（Ｉ）で表される（メタ）アクリル酸エステル単量体単位（Ｃ）：０．５〜８質量％と、

（式（Ｉ）中、Ｒ^１１は、水素原子又はメチル基を表し、Ｒ^１２は、炭素数６〜２０の有機基（但し、フェニル基、ベンジル基を除く）を表す。）
メタクリル酸エステル単量体と共重合可能なその他のビニル系単量体単位（Ｄ）：０〜２０質量％と
を含み、
下記条件（１）〜（２）、（４）を満たすことを特徴とする、メタクリル系樹脂。
（１）ゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定した重量平均分子量が、６．５万〜３０万である。
（２）前記（Ｂ）構造単位の含有量が、前記（Ｂ）構造単位と前記（Ｄ）単量体単位との合計量を１００質量％として、４５〜１００質量％である。
（４）ゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定した重量平均分子量が１万以下の成分の含有量が、メタクリル系樹脂を１００質量％として、０．１〜５．０質量％である。
［２］
さらに下記条件（３）を満たす、［１］に記載のメタクリル系樹脂。
（３）ＧＣ／ＭＳの測定を実施したときに、保持時間２２〜３２分に検出される成分の合計の含有量が、前記メタクリル系樹脂を１００質量％として、０．０１〜０．４０質量％である。
［３］
ガラス転移温度が１１５℃以上である、［１］又は［２］に記載のメタクリル系樹脂。
［４］
前記（Ｂ）構造単位が、マレイミド系構造単位（Ｂ−１）、グルタル酸無水物系構造単位（Ｂ−２）、グルタルイミド系構造単位（Ｂ−３）、及びラクトン環構造単位（Ｂ−４）からなる群より選ばれる少なくとも一種の構造単位を含む、［１］〜［３］のいずれかに記載のメタクリル系樹脂。 [1]
Following general formula (1) in represented Ru monomer unit (A): and from 46 to 96.5 wt%,

(In the formula (1), R ¹ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R ² represents a group having 1 to 3 carbon atoms.)
Structural unit (B) having a ring structure in the main chain: 3 to 30% by mass,
(Meta) acrylic acid ester monomer unit (C) represented by the following general formula (I): 0.5 to 8% by mass,

(In the formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an organic group having 6 to 20 carbon atoms (excluding phenyl group and benzyl group).
Other vinyl-based monomer unit (D) copolymerizable with the methacrylic acid ester monomer: 0 to 20% by mass,
A methacrylic resin, which satisfies the following conditions (1), (2) , and (4 ).
(1) The weight average molecular weight measured by gel permeation chromatography (GPC) is 65,000 to 300,000.
(2) The content of the (B) structural unit is 45 to 100% by mass, where the total amount of the (B) structural unit and the (D) monomer unit is 100% by mass.
(4) The content of the component having a weight average molecular weight of 10,000 or less measured by gel permeation chromatography (GPC) is 0.1 to 5.0% by mass, assuming that the methacrylic resin is 100% by mass.
[2]
The methacrylic resin according to [1], which further satisfies the following condition (3).
(3) When the GC / MS measurement is carried out, the total content of the components detected in the holding time of 22 to 32 minutes is 0.01 to 0.40 mass with the methacrylic resin as 100% by mass. % .
[3]
The methacrylic resin according to [1] or [2] , wherein the glass transition temperature is 115 ° C. or higher.
[4]
The structural unit (B) is a maleimide-based structural unit (B-1), a glutaric anhydride-based structural unit (B-2), a glutarimide-based structural unit (B-3), and a lactone ring structural unit (B-). The methacryl-based resin according to any one of [1] to [3] , which comprises at least one structural unit selected from the group consisting of 4).

[5]
A methacrylic resin composition, which comprises the methacrylic resin according to any one of [1] to [4] .
[6]
The methacrylic resin composition according to [5] , further comprising 0.01 to 5 parts by mass of a heat stabilizer with respect to 100 parts by mass of the methacrylic resin.
[7]
The methacrylic resin composition according to [5] or [6] , further containing 0.01 to 5 parts by mass of an ultraviolet absorber with respect to 100 parts by mass of the methacrylic resin.

[8]
A display front plate comprising the methacrylic resin composition according to any one of [5] to [7] .

[9]
An optical lens comprising the methacrylic resin composition according to any one of [5] to [7] .

[10]
A light guide plate comprising the methacrylic resin composition according to any one of [5] to [7] .

[11]
A meter panel comprising the methacrylic resin composition according to any one of [5] to [7] .

[12]
An in-vehicle center console comprising the methacrylic resin composition according to any one of [5] to [7] .

According to the present invention, a methacrylic resin having excellent heat resistance, thermal stability, color tone, and molding processability, a methacrylic resin composition containing the same, and a display front plate, an optical lens, a light guide plate, and a meter containing the same. Panels and in-vehicle center consoles can be provided.

It is a figure which shows the outline of the elution curve when the methacrylic resin or the methacrylic resin composition of this embodiment was measured by gel permeation chromatography (GPC).

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description and varies within the scope of the gist thereof. It can be transformed and implemented.
In the following, the structural unit constituting the polymer forming the methacrylic resin of the present embodiment is referred to as "~ monomer unit" and / or "~ monomer unit" including a plurality of the "~ monomer units". It is called "structural unit".
In addition, the constituent material of such "~ monomer unit" may be simply described as "~ monomer" by omitting the "unit".
In the present specification, a molded product containing the methacrylic resin composition of the present embodiment, such as a display front plate, an optical lens, a light guide plate, a meter panel, and an in-vehicle center console, is referred to as a "molded product of the present embodiment". It may be called.

（式（１）中、Ｒ^１は、炭素数が１〜６の置換若しくは非置換のアルキル基を表し、Ｒ^２は炭素数が１〜３の基を表す。）
主鎖に環構造を有する構造単位（Ｂ）：３〜３０質量％と、
下記一般式（Ｉ）で表される（メタ）アクリル酸エステル系単量体単位（Ｃ）：０．５〜８質量％と、

（式（Ｉ）中、Ｒ^１１は、水素原子又はメチル基を表し、Ｒ^１２は、炭素数６〜２０の有機基（但し、フェニル基、ベンジル基を除く）を表す。）
メタクリル酸エステル単量体と共重合可能なその他のビニル系単量体単位（Ｄ）：０〜２０質量％と
を含み、下記条件（１）〜（２）を満たすことを特徴とする。
（１）ゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定した重量平均分子量が、６．５万〜３０万である。
（２）前記（Ｂ）構造単位の含有量が、前記（Ｂ）構造単位と前記（Ｄ）単量体単位との合計量を１００質量％として、４５〜１００質量％である。 (Methacrylic resin)
The methacrylic resin of the present embodiment is
Methacrylic acid ester monomer unit (A) represented by the following general formula (1): 46 to 96.5% by mass.

(In the formula (1), R ¹ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R ² represents a group having 1 to 3 carbon atoms.)
Structural unit (B) having a ring structure in the main chain: 3 to 30% by mass,
(Meta) acrylic acid ester-based monomer unit (C) represented by the following general formula (I): 0.5 to 8% by mass,

(In the formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an organic group having 6 to 20 carbon atoms (excluding phenyl group and benzyl group).
The other vinyl-based monomer unit (D) copolymerizable with the methacrylic acid ester monomer: 0 to 20% by mass is contained, and the following conditions (1) and (2) are satisfied.
(1) The weight average molecular weight measured by gel permeation chromatography (GPC) is 65,000 to 300,000.
(2) The content of the (B) structural unit is 45 to 100% by mass, where the total amount of the (B) structural unit and the (D) monomer unit is 100% by mass.

Hereinafter, the monomer unit and the structural unit contained in the methacrylic resin will be described in detail.

((Methacrylic acid ester monomer unit (A)))
The methacrylic acid ester monomer unit (A) (hereinafter, may be referred to as (A) monomer unit) constituting the methacrylic acid resin of the present embodiment is represented by the following general formula (1). The monomer unit is preferably used.

In the general formula (1), R ¹ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with, for example, a hydroxyl group. R ¹ is preferably a methyl group.
R ² may be a group having 1 to 3 carbon atoms (preferably a hydrocarbon group having 1 to 3 carbon atoms), and the hydrocarbon group may be substituted with, for example, a hydroxyl group. R ² is preferably a linear or branched hydrocarbon group having 1 to 3 carbon atoms, more preferably a linear or branched saturated hydrocarbon group having 1 to 3 carbon atoms.

The monomer forming the methacrylic acid ester monomer unit (A) represented by the general formula (1) is not particularly limited, but the methacrylic acid ester monomer represented by the following general formula (2) is used. It is preferable to use it.

In the general formula (2), R ¹ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with, for example, a hydroxyl group. R ¹ is preferably a methyl group.
R ² represents a group of 1 to 3 (preferably a hydrocarbon group having 1 to 3 carbon atoms), and the hydrocarbon group may be substituted with, for example, a hydroxyl group. R ² is preferably a linear or branched hydrocarbon group having 1 to 3 carbon atoms, more preferably a linear or branched saturated hydrocarbon group having 1 to 3 carbon atoms.

As a specific example of such a monomer, methyl methacrylate, ethyl methacrylate, propyl methacrylate and isopropyl methacrylate are preferable from the viewpoint of heat resistance, handleability and optical properties, and Tg is kept high and coloring is further suppressed. From the viewpoint, methyl methacrylate and ethyl methacrylate are preferable, and from the viewpoint of availability and the like, methyl methacrylate is preferable.
The methacrylic acid ester monomer may be used alone or in combination of two or more.

The methacrylic acid ester monomer unit (A) of the methacrylic resin is a methacrylic resin, a methacrylic resin composition, and a molded product of the present embodiment, depending on the structural unit (B) having a ring structure in the main chain, which will be described later. From the viewpoint of imparting sufficient heat resistance to the resin, the methacrylic resin contains 46 to 96.5% by mass, preferably 50 to 96.5% by mass, more preferably 55 to 96.5% by mass, and further. It is preferably contained in an amount of 55 to 95% by mass, more preferably 60 to 93% by mass, and particularly preferably 60 to 90% by mass.

((Structural unit (B) having a ring structure in the main chain))
The structural unit (B) having a ring structure in the main chain (hereinafter, may be referred to as (B) structural unit) constituting the methacrylic resin of the present embodiment is a maleimide-based structural unit (B-1). , Glutaric acid anhydride-based structural unit (B-2), glutarimide-based structural unit (B-3), and lactone ring structural unit (B-4) may contain at least one structural unit selected from the group. preferable.
As the structural unit (B) having a ring structure in the main chain, only one type may be used alone, or two or more types may be combined.

[Maleimide-based structural unit (B-1)]
As the maleimide-based structural unit (B-1) constituting the methacrylic resin of the present embodiment, the structural unit represented by the following general formula (3) is preferably used.

In the general formula (3), R ¹ has a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and 6 carbon atoms. Represents any one selected from the group consisting of ~ 12 aryl groups, and the alkyl group, alkoxy group, cycloalkyl group, and aryl group may have a substituent on the carbon atom.

The monomer for forming the maleimide-based structural unit (B-1) is not particularly limited. -Alkyl group-substituted maleimide; N-phenylmaleimide, N-methylphenylmaleimide, N-ethylphenylmaleimide, N-butylphenylmaleimide, N-dimethylphenylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-( Examples thereof include N-aryl group-substituted maleimides such as o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, and N- (p-chlorophenyl) maleimide.
From the viewpoint of imparting heat resistance and moisture heat resistance, the monomer is preferably N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl). ) Maleimide, N- (p-chlorophenyl) maleimide, more preferably N-cyclohexylmaleimide, N-phenylmaleimide, and further preferably N-phenyl, from the viewpoint of easy availability and imparting heat resistance. Maleimide can be mentioned.
As the maleimide-based structural unit (B-1) described above, only one type may be used alone, or two or more types may be used in combination.

[Glutaric anhydride-based structural unit (B-2)]
The glutaric anhydride-based structural unit (B-2) constituting the methacrylic acid-based resin of the present embodiment may be formed after resin polymerization.
As the structural unit (B-2), the structural unit represented by the following general formula (4) is preferably used.

In the general formula (4), R ¹ and R ² each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group is, for example, a hydroxyl group. It may be replaced.
As the above-mentioned glutaric anhydride-based structural unit (B-2), only one type may be used alone, or two or more types may be used in combination.

The method for forming the glutaric anhydride-based structural unit (B-2) is not particularly limited, but for example, a monomer having a structure represented by the following general formula (5) can be used as the above-mentioned methacrylic acid ester monomer unit. Examples thereof include a method of copolymerizing with the monomer forming (A) and then cyclizing by heat treatment in the presence / absence of a catalyst.

In the general formula (5), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with, for example, a hydroxyl group.
R ² represents a hydrogen atom or a t-butyl group.

Further, as long as the effect of the present invention can be exhibited, the monomer having the structure represented by the general formula (5) may remain unreacted in the methacrylic resin.

[Glutarimide-based structural unit (B-3)]
The glutarimide-based structural unit (B-3) constituting the methacrylic resin of the present embodiment may be formed after resin polymerization.
As the structural unit (B-3), the structural unit represented by the following general formula (6) is preferably used.

In the general formula (6), R ¹ and R ² each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group is, for example, a hydroxyl group. It may be replaced.
Further, R ³ represents any one selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 18 carbon atoms. ..
Particularly preferably, R ¹ , R ² and R ³ are all methyl groups.
As the glutarimide-based structural unit (B-3) described above, only one type may be used alone, or two or more types may be used in combination.

The content of the glutarimide-based structural unit (B-3) is not particularly limited, and can be appropriately determined in consideration of heat resistance, molding processability, optical properties, and the like.
The content of the glutarimide-based structural unit (B-3) is preferably 1 to 60% by mass, more preferably 3 to 50% by mass, and particularly preferably 3 with the methacrylic resin as 100% by mass. ~ 25% by mass.
The content of the glutarimide-based structural unit (B-3) can be calculated by, for example, the method described in [0136] to [0137] of International Publication No. 2015/098096.

The acid value of the resin containing the glutarimide-based structural unit (B-3) is preferably 0.50 mmol / g or less, more preferably 0, in consideration of the balance of physical properties, molding processability, color tone, etc. of the resin. It is .45 mmol / g or less.
The acid value can be calculated by, for example, the titration method described in Japanese Patent Application Laid-Open No. 2005-23272.

Glutalimide-based structural unit (B-3) is a method in which ammonia or amine is reacted with urea or an unsubstituted urea reaction at a high temperature after copolymerizing a methacrylate ester and / or methacrylate, methyl methacrylate-styrene. It can be obtained by a known method such as a method of reacting a copolymer with ammonia or amine, a method of reacting polymethacrylic acid anhydride with ammonia or amine, or the like.
Specific examples thereof include the method described in US Pat. No. 4,246,374 of RM Kopcik.

Further, by imidizing an acid anhydride such as maleic anhydride, a half ester of the acid anhydride and a linear or branched alcohol having 1 to 20 carbon atoms, and an α, β-ethylenically unsaturated carboxylic acid. Also, the glutarimide-based structural unit (B-3) can be formed.

Further, as another preferable preparation method, a (meth) acrylic acid ester and, if necessary, an aromatic vinyl monomer or another vinyl monomer are polymerized, and then an imidization reaction is carried out to carry out the above-mentioned glutar. A method of obtaining a resin containing an imide-based structural unit (B-3) can also be mentioned.
In the step of the imidization reaction, an imidizing agent may be used, and if necessary, a ring closure accelerator may be added. Here, as the imidizing agent, ammonia or a primary amine can be used. As the primary amine, methylamine, ethylamine, n-propylamine, cyclohexylamine and the like can be preferably used.
The method for carrying out the imidization reaction is not particularly limited, and conventionally known methods can be used. Examples thereof include a method using an extruder, a horizontal twin-screw reactor, and a batch type reaction vessel. The extruder is not particularly limited, and a single-screw extruder, a twin-screw extruder or a multi-screw extruder can be preferably used. More preferably, a tandem type reaction extruder in which two twin-screw extruders are arranged in series can be used.
Further, in producing the above resin, in addition to the step of imidization reaction, an esterification step of treating with an esterifying agent can be included. By including the esterification step, the carboxyl group contained in the resin produced as a by-product during the imidization step can be converted into an ester group, and the acid value of the resin can be adjusted to a desired range. Here, the esterifying agent is not particularly limited as long as the effects of the present application can be exhibited, but dimethyl carbonate and trimethyl acetate can be preferably used. The amount of the esterifying agent used is not particularly limited, but is preferably 0 to 12 parts by mass with respect to 100 parts by mass of the resin. Further, in addition to the esterifying agent, an aliphatic tertiary amine such as trimethylamine, triethylamine, or tributylamine can be used in combination as a catalyst.

[Lactone ring structure unit (B-4)]
The lactone ring structural unit (B-4) constituting the methacrylic resin of the present embodiment may be formed after resin polymerization.
As the structural unit (B-4), the structural unit represented by the following general formula (7) is preferably used.

In the general formula (7), R ¹ , R ² , and R ³ independently represent a hydrogen atom or an organic group having 1 to 20 carbon atoms. The organic group may contain an oxygen atom.
As the above-mentioned lactone ring structural unit (B-4), only one type may be used alone, or two or more types may be used in combination.

The method for forming the polymer containing the lactone ring structural unit (B-4) is not particularly limited, but a monomer having a hydroxyl group in the side chain, for example, a single amount having a structure represented by the following general formula (8). The obtained copolymer is obtained after copolymerizing a compound (such as methyl 2- (hydroxymethyl) acrylate) and a monomer having an ester group such as the above-mentioned methacrylic acid ester-based monomer (A). , A method of producing by introducing a lactone ring structure into a polymer by heat treatment in the presence / absence of a predetermined catalyst can be mentioned.

In the general formula (8), R ¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with, for example, a hydroxyl group.
R ² represents a group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and the hydrocarbon group may be substituted with, for example, a hydroxyl group.
Particularly preferably, R ¹ is a hydrogen atom and R ² is a methyl group.

Further, as long as the effect of the present invention can be exhibited, the monomer having the structure represented by the general formula (8) may remain unreacted in the methacrylic resin.

The structural units (B) contained in the methacrylic resins described so far include maleimide-based structural units (B-1) and glutarimide-based structural units (B-3) in terms of thermal stability and moldability. It is preferable to include at least one structural unit selected from the group, and more preferably to include a maleimide-based structural unit (B-1).
Among the maleimide-based structural units (B-1), in consideration of availability, it is preferably an N-cyclohexylmaleimide-based structural unit and / or an N-aryl-substituted maleimide-based structural unit, with a small amount of addition. Considering the effect of imparting heat resistance, an N-aryl-substituted maleimide-based structural unit is more preferable, and an N-phenylmaleimide-based structural unit is more preferable.

The structural unit (B) having a ring structure in the main chain is contained in the methacrylic resin in an amount of 3 to 30% by mass from the viewpoint of heat resistance, thermal stability, strength and fluidity of the methacrylic resin composition of the present embodiment. Is. The content of the structural unit (B) having a ring structure in the main chain in the methacrylic resin is preferably 5% by mass or more from the viewpoint of imparting heat resistance and thermal stability to the methacrylic resin composition of the present embodiment. It is more preferably 7% by mass or more, still more preferably 8% by mass or more. Further, from the viewpoint of maintaining the strength and fluidity required for the molded product in a well-balanced manner, the content of the structural unit (B) having a ring structure in the main chain in the methacrylic resin is preferably 28% by mass or less. It is preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 18% by mass or less, and even more preferably less than 15% by mass.

By including (B) a structural unit having a ring structure in the main chain in the methacrylic resin, thermal decomposition is suppressed and the amount of volatile components generated is reduced when the methacrylic resin is placed in a high temperature environment. Can be done. As a result, the effect of improving the thermal stability of the methacrylic resin of the present embodiment can be obtained.

（式（Ｉ）中、Ｒ^１１は、水素原子又はメチル基を表し、Ｒ^１２は、炭素数６〜２０の有機基（ベンジル基、フェニル基は含まない）を表す。）
なお、式（Ｉ）中のＲ^１１、Ｒ^１２は、酸素原子や硫黄原子を含んでいてもよい。 (((Meta) acrylic acid ester-based monomer unit (C)))
The (meth) acrylic acid ester-based monomer unit (C) (hereinafter, may be referred to as (C) monomer unit) constituting the methacrylic resin of the present embodiment is represented by the following general formula (I). ) Is a monomer unit.

(In the formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an organic group having 6 to 20 carbon atoms (excluding a benzyl group and a phenyl group).)
In addition, R ¹¹ and R ¹² in the formula (I) may contain an oxygen atom and a sulfur atom.

As R ¹¹ in the (C) monomer unit, a hydrogen atom is preferable from the viewpoint of obtaining a more excellent color suppressing effect.
The ^{R 12} in (C) monomer units, from the viewpoint that the resulting more excellent coloring suppressing effect, organic group having 6 to 18 carbon atoms (preferably, a hydrocarbon group having 6 to 18 carbon atoms) (wherein, A benzyl group (excluding a benzyl group and a phenyl group) is preferable, and an organic group having 10 to 18 carbon atoms (preferably a hydrocarbon group having 10 to 18 carbon atoms (excluding a benzyl group and a phenyl group) is more preferable). from the viewpoint of excellent coloring suppressing effect is obtained, as the hydrocarbon group for R ^12, is preferably a hydrocarbon group having no aromatic hydrocarbon ring, more preferably a hydrocarbon group having no cyclic structure , More preferably a hydrocarbon group having no linear or branched ring structure, and particularly preferably a saturated hydrocarbon group having no linear or branched ring structure.

（式（ＩＩ）中、Ｒ^１１は、水素原子又はメチル基を表し、Ｒ^１２は、炭素数６〜２０の有機基（ベンジル基、フェニル基は含まない）を表す。）
なお、式（Ｉ）中のＲ^１１、Ｒ^１２は、酸素原子や硫黄原子を含んでいてもよい。
式（ＩＩ）中のＲ^１１としては、一層優れた着色抑制効果が得られる観点から、水素原子が好ましい。
着色改良の推定メカニズムとしては、樹脂が分解していく際の末端ラジカルからエステル側鎖水素引抜き、脱オレフィン反応が関与していると考えられる。そのため、式（ＩＩ）中のＲ^１２としては、脱オレフィン反応の起こりやすさ、つまり、一層優れた着色抑制効果が得られる観点から、炭素数６〜１８の有機基（好ましくは炭素数６〜１８の炭化水素基）（但し、ベンジル基、フェニル基を除く）が好ましく、炭素数１０〜１８の有機基（好ましくは炭素数１０〜１８の炭化水素基（但し、ベンジル基、フェニル基を除く）がより好ましい。また、一層優れた着色抑制効果が得られる観点から、Ｒ^１２における炭化水素基としては、芳香族炭化水素環を有さない炭化水素基であることが好ましく、より好ましくは環構造を有さない炭化水素基、さらに好ましくは直鎖状又は分岐鎖状の環構造を有さない炭化水素基、特に好ましくは直鎖状又は分岐鎖状の環構造を有さない飽和炭化水素基である。 The monomer forming the (meth) acrylic acid ester monomer unit (C) represented by the general formula (I) is not particularly limited, but the (meth) acrylic represented by the following general formula (II). It is preferable to use an acid ester monomer.

(In formula (II), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an organic group having 6 to 20 carbon atoms (excluding a benzyl group and a phenyl group).)
In addition, R ¹¹ and R ¹² in the formula (I) may contain an oxygen atom and a sulfur atom.
As R ¹¹ in the formula (II), a hydrogen atom is preferable from the viewpoint of obtaining a more excellent color suppressing effect.
It is considered that the ester side chain hydrogen extraction and deolefination reaction are involved from the terminal radicals when the resin is decomposed as the estimation mechanism of the coloring improvement. Therefore, as the R ¹² in Formula (II), occurs ease of removal olefin reaction, that is, from the viewpoint that the resulting more excellent coloring suppressing effect, organic group having 6 to 18 carbon atoms (preferably 6 to carbon atoms 18 hydrocarbon groups) (excluding benzyl group and phenyl group) are preferable, and organic groups having 10 to 18 carbon atoms (preferably hydrocarbon groups having 10 to 18 carbon atoms (excluding benzyl group and phenyl group) are excluded. ) Is more preferable. Further, from the viewpoint of obtaining a more excellent color suppressing effect, the hydrocarbon group in R ¹² is preferably a hydrocarbon group having no aromatic hydrocarbon ring, and more preferably a ring. A hydrocarbon group having no structure, more preferably a hydrocarbon group having no linear or branched ring structure, particularly preferably a saturated hydrocarbon having no linear or branched ring structure. It is a group.

As such a monomer, an acrylic acid ester monomer is preferable to a methacrylic acid ester monomer from the viewpoint of enhancing heat resistance, and specific examples thereof include hexyl acrylate, octyl acrylate, and decyl acrylate. , Dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, acrylic acid (t-butylcyclohexyl), etc. Among them, hexyl acrylate, dodecyl acrylate, acrylic acid from the viewpoint of obtaining a more excellent color suppressing effect. Octadecyl is preferred.

The methacrylic resin is randomly decomposed at a temperature higher than 270 to 300 ° C. Here, by containing an appropriate amount of the (C) monomer unit, in addition to the zippering of the main monomer and the desorption of the dimer during the decomposition reaction, the ester of the (C) monomer unit Extraction of hydrogen atoms from the side chain alkyl portion and β-cleavage of the side chain are likely to occur. By using a monomer in which this side chain elimination reaction is likely to occur as a comonomer, it is considered that the decomposition reaction is stopped by the side chain elimination reaction and coloring is easily suppressed.
The content of the (C) monomer unit in the methacrylic resin is 0.5% by mass or more, preferably 1% by mass or more, and more preferably 1 from the viewpoint of being able to effectively suppress coloring in the above reaction. It is 5.5% by mass or more. If the content of the (C) monomer unit is large, Tg is lowered and the coloring suppressing effect due to the side chain elimination reaction described above is saturated. Therefore, the content of the (C) monomer unit is 8% by mass or less, preferably 7% by mass or less, more preferably 6% by mass or less, still more preferably 5 from the viewpoint of effectively suppressing coloring. It is mass% or less, more preferably 4 mass% or less, further preferably 3 mass% or less, and particularly preferably 2 mass% or less.
From the viewpoint of more effectively suppressing coloring, it is preferable that the content of the (C) monomer unit is in the above range and the glass transition temperature of the methacrylic resin is 115 ° C. or higher.

Since the specific comonomer added as the (C) monomer unit is a bulky monomer, the copolymerization with the (A) monomer unit is low and the conversion rate is difficult to increase. Therefore, by increasing the conversion rate, it is possible to obtain a sufficient effect of suppressing coloration by containing the (C) monomer unit, and further, it is possible to reduce the residual monomer. Since the residual monomer may become a coloring-causing substance during the devolatile step of treating at a high temperature, coloring is further suppressed.
From the viewpoint of obtaining a sufficient coloration suppressing effect, it is preferable to increase the conversion rate of the (C) monomer unit after polymerization as much as possible. The conversion rate of the (C) monomer unit after polymerization is preferably 80% or more, more preferably 90% or more, still more preferably 94% or more, from the viewpoint of obtaining a more excellent color suppressing effect.
The conversion rate of the (C) monomer unit after polymerization can be measured by the method described in Examples described later. Further, the conversion rate of the (C) monomer unit after polymerization is adjusted by, for example, the type of the polymerization initiator, the polymerization temperature, the polymerization time, the type of the (C) monomer, the ratio of the monomer to the solvent, and the like. can do.

((Other vinyl-based monomer unit (D) copolymerizable with methacrylic acid ester monomer))
Other vinyl-based monomer units (D) (hereinafter, (D) monomer units) that are copolymerizable with the methacrylic acid ester monomer constituting the methacrylic acid-based resin of the present embodiment may be described. ) Examples include aromatic vinyl-based monomer unit (D-1), (meth) acrylic acid ester monomer unit (D-2), vinyl cyanide-based monomer unit (D-3), and others. The monomer unit (D-4) of is mentioned.
As the other vinyl-based monomer unit (D) copolymerizable with the methacrylic acid ester monomer, only one type may be used alone, or two or more types may be combined.

The material of the (D) monomer unit can be appropriately selected according to the properties required for the methacrylic resin of the present embodiment, but the thermal stability, fluidity, mechanical properties, chemical resistance, and the like can be selected. Aromatic vinyl-based monomeric units (D-1), (meth) acrylic acid ester monomeric units (D-2), and vinyl cyanide-based monomeric units (D-), where properties are particularly required. At least one selected from the group consisting of 3) is suitable.

[Aromatic vinyl monomer unit (D-1)]
The monomer forming the aromatic vinyl-based monomer unit (D-1) constituting the methacrylic resin of the present embodiment is not particularly limited, but is represented by the following general formula (9). Aromatic vinyl-based monomers are preferable.

In the general formula (9), R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with, for example, a hydroxyl group.
R ² is a group consisting of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 8 carbon atoms, and an aryloxy group having 6 to 8 carbon atoms. R ² may be all the same group or different groups. Also, it may form a ring structure with R ² to each other.
n represents an integer from 0 to 5.

Specific examples of the monomer represented by the above general formula (9) are not particularly limited, but are styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and 2,4-dimethyl. Styrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenylbenzene (α-methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, Examples thereof include isopropenyloctylbenzene.
Among the above, styrene and isopropenylbenzene are preferable, and styrene is more preferable from the viewpoint of imparting fluidity and reducing unreacted monomers by improving the polymerization conversion rate.
These may be appropriately selected depending on the required properties in the methacrylic resin composition of the present embodiment.

When the aromatic vinyl-based monomer unit (D-1) is used, the content is (A) monomer unit and (B) in consideration of the balance between heat resistance, reduction of residual monomer species, and fluidity. When the total amount with the structural unit is 100% by mass, it is preferably 23% by mass or less, more preferably 20% by mass or less, still more preferably 18% by mass or less, still more preferably 15% by mass or less. Even more preferably, it is 10% by mass or less.

When the aromatic vinyl-based monomer unit (D-1) is used in combination with the maleimide-based structural unit (B-1) described above, the (D-1) monomer with respect to the content of the (B-1) structural unit. The unit content ratio (mass ratio) (that is, (D-1) content / (B-1) content) is the processing fluidity during molding of the film and silver streak due to the reduction of residual monomers. From the viewpoint of the effect of reducing the amount of waste, it is preferably 0.3 to 5.
Here, from the viewpoint of maintaining a good color tone and heat resistance, the upper limit value is preferably 5 or less, more preferably 3 or less, and further preferably 1 or less. Further, from the viewpoint of reducing the residual monomer, the lower limit value is preferably 0.3 or more, more preferably 0.4 or more.
As the above-mentioned aromatic vinyl monomer (D-1), only one type may be used alone, or two or more types may be used in combination.

[(Meta) acrylic acid ester monomer unit (D-2)]
The monomer forming the (meth) acrylic acid ester monomer unit (D-2) constituting the methacrylic resin of the present embodiment is not particularly limited, but is represented by the following general formula (10). The (meth) acrylic acid ester monomer to be produced is preferable.
The (meth) acrylic acid ester monomer unit (D-2) includes the methacrylic acid ester monomer unit (A) and the (meth) acrylic acid ester monomer unit (C). Make it not exist.

In the general formula (10), R ¹ represents a hydrogen atom, an alkoxy group having 1 to 12 carbon atoms, or a methyl group. In formula (10), when R ¹ is a hydroxyalkyl group having 1 to 12 carbon atoms (particularly, an alkyl group having 1 to 12 carbon atoms having at least one hydroxy group at the terminal carbon atom), R ² Represents an alkyl group, a benzyl group, or a phenyl group having 1 to 5 carbon atoms, and when R ¹ is a hydrogen atom or a methyl group, R ² represents a t-butyl group, a benzyl group, or a phenyl group. ..

As the monomer for forming the (meth) acrylic acid ester monomer unit (D-2), the methacrylic acid-based resin of the present embodiment may be used from the viewpoint of enhancing heat resistance, fluidity, and thermal stability. From the viewpoint of adjusting optical properties such as refraction, t-butyl methacrylate, t-butyl acrylate, phenyl acrylate, benzyl acrylate, methyl 2- (hydroxymethyl) acrylate and the like are preferable, and from the viewpoint of availability. Therefore, t-butyl acrylate is more preferable.
As the (meth) acrylic acid ester monomer unit (D-2), only one type may be used alone, or two or more types may be used in combination.

When the (meth) acrylic acid ester monomer unit (D-2) is used, the content is the sum of the (A) monomer unit and the (B) structural unit from the viewpoint of heat resistance and thermal stability. When the amount is 100% by mass, it is preferably 5% by mass or less, and more preferably 3% by mass or less.

[Vinyl cyanide monomer unit (D-3)]
The monomer forming the vinylidene cyanide monomer unit (D-3) constituting the methacrylic resin of the present embodiment is not particularly limited, but is, for example, acrylonitrile, methacrylonitrile, and cyanide. Examples thereof include vinylidene, and among them, acrylonitrile is preferable from the viewpoint of easy availability and imparting chemical resistance.
As the vinyl cyanide-based monomer unit (D-3), only one type may be used alone, or two or more types may be used in combination.

When the vinyl cyanide-based monomer unit (D-3) is used, the content is the total amount of the (A) monomer unit and the (B) structural unit from the viewpoint of maintaining solvent resistance and heat resistance. When is 100% by mass, it is preferably 15% by mass or less, more preferably 12% by mass or less, and further preferably 10% by mass or less.

[Polymer unit (D-4) other than (D-1) to (D-3)]
The monomer forming the monomer unit (D-4) other than (D-1) to (D-3) constituting the methacrylic resin of the present embodiment is not particularly limited, but for example. , Amids such as acrylamide and methacrylicamide; ethylene glycol such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate and tetraethylene glycol di (meth) acrylate or an oligomer thereof. Both terminal hydroxyl groups are esterified with acrylic acid or methacrylic acid; hydroxyl groups of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate are esterified with acrylic acid or methacrylic acid; tri Polyhydric alcohol derivatives such as methylolpropane and pentaerythritol esterified with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene and the like can be mentioned.

Among the monomers constituting the monomer unit (D) described above, at least one selected from the group consisting of styrene and acrylonitrile is preferable from the viewpoint of availability.

The content of the other vinyl-based monomer unit (D) copolymerizable with the methacrylic acid ester monomer is 100% by mass of the methacrylic acid-based resin from the viewpoint of enhancing the effect of imparting heat resistance by the structural unit (B). It is 0 to 20% by mass, preferably 0 to 18% by mass, and more preferably 0 to 15% by mass.
In particular, when a crosslinkable polyfunctional (meth) acrylate having a plurality of reactive double bonds is used as the (D) monomer unit, the content of the (D) monomer unit is the fluidity of the polymer. From the above viewpoint, it is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and further preferably 0.2% by mass or less.

In particular, in the present embodiment, from the viewpoint of heat resistance and optical properties of the methacrylic resin, the structural unit (B) is based on the total amount of the structural unit (B) and the monomer unit (D) being 100% by mass. The content of is 45 to 100% by mass. At this time, the content of the structural unit (D) is 0 to 55% by mass. The content of the structural unit (B) is preferably 50 to 100% by mass, more preferably 50 to 90% by mass, and further preferably 50 to 80% by mass.

Hereinafter, the characteristics of the methacrylic resin of the present embodiment will be described.

<Weight average molecular weight, molecular weight distribution>
The weight average molecular weight (Mw) of the methacrylic resin of the present embodiment is 65,000 to 300,000.
By setting the weight average molecular weight of the methacrylic resin in the above range, the methacrylic resin and the methacrylic resin composition of the present embodiment are excellent in mechanical strength such as Charpy impact strength and fluidity. From the viewpoint of maintaining mechanical strength, the weight average molecular weight is preferably 65,000 or more, more preferably 70,000 or more, still more preferably 80,000 or more, and even more preferably 100,000 or more. Further, the weight average molecular weight is preferably 250,000 or less, more preferably 230,000 or less, still more preferably 220,000 or less, still more preferably 200,000 or less, particularly preferably, from the viewpoint of ensuring fluidity during molding. It is preferably 180,000 or less, particularly preferably 170,000 or less.
The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the methacrylic resin is preferably 1.5 to 5 in consideration of the balance between fluidity, mechanical strength, and solvent resistance. .. It is more preferably 1.5 to 4.5, still more preferably 1.6 to 4, even more preferably 1.6 to 3, and even more preferably 1.5 to 2.5.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by gel permeation chromatography (GPC). Specifically, a standard methacrylic resin whose monodisperse weight average molecular weight, number average molecular weight and peak molecular weight are known in advance and can be obtained as a reagent, and an analytical gel column in which high molecular weight components are eluted first are used, and elution time and weight average Create a calibration line from the molecular weight. Next, the weight average molecular weight and the number average molecular weight of the methacrylic resin sample to be measured can be obtained from the obtained calibration curve. Specifically, it can be measured by the method described in Examples described later.

<Ratio of components in a specific molecular weight range>
In the methacrylic resin of the present embodiment, the content of the component having a weight average molecular weight of 10,000 or less as measured by gel permeation chromatography (GPC) is preferably 0.1 to 5.0% by mass. ..
By setting the content to 0.1% by mass or more, the processing fluidity can be improved. The lower limit is preferably 0.2% by mass, more preferably 0.5% by mass, and even more preferably 0.6% by mass. Further, by setting the content to 5% by mass or less, it is possible to reduce appearance defects such as reduction of silver streaks during molding, and further, it is possible to improve mold separation during molding. .. Further, since most of the coloring-causing substances are low molecular weight components, a more excellent coloring suppressing effect can be obtained by reducing the amount of the components having a weight average molecular weight of 10,000 or less. The upper limit is more preferably 4.0% by mass, still more preferably 3.0% by mass, and particularly preferably 2.0% by mass.
The content of the component having a weight average molecular weight of 10,000 or less can be obtained from, for example, the area area ratio obtained from the GPC dissolution curve. Specifically, in FIG. 1, the starting point of the dissolution curve is A. When the end point is B, the point on the baseline at the elution time at which the weight average molecular weight is 10,000 is X, and the point on the GPC elution curve is Y, it is surrounded by the curve BY, the line segment BX, and the line segment XY. The ratio of the area to the area area in the GPC elution curve can be obtained as the content (mass%) of the component having a weight average molecular weight of 10,000 or less.
Preferably, it can be measured by the method of the following examples.

In the methacrylic resin of the present embodiment, the content of the component having a weight average molecular weight of more than 10,000 and 50,000 or less is preferably 10.0 to 25.0% by mass.
By setting the content to 10.0 to 25.0% by mass, it is possible to suppress the occurrence of streak unevenness during the film forming process, and the stickability to the roll during the film forming is improved. The lower limit value is more preferably 12.0% by mass, still more preferably 13. It is 0% by mass, and the upper limit is more preferably 24.0% by mass.
The content of the component having a weight average molecular weight of more than 10,000 and 50,000 or less can be determined in the same manner as the content of the component having a weight average molecular weight of 10,000 or less.

In the methacrylic resin of the present embodiment, the ratio of the content (b) of the component having a weight average molecular weight of more than 50,000 to the content (a) of the above-mentioned component having a weight average molecular weight of more than 10,000 and 50,000 or less ( b / a) is preferably 2.5 to 8.5 from the viewpoint of improving the balance between thermal stability and processability.
Looking at the abundance ratio of high molecular weight and low molecular weight, if the low molecular weight ratio is high, the processing fluidity will increase due to the effect of the viscosity difference between the high molecular weight and low molecular weight during heat processing. Although it is excellent, it tends to have high adhesiveness to the roll during film processing, while when the high molecular weight substance ratio is high, streak unevenness tends to occur during film processing.
When it is desired to improve the stickability after imparting the characteristics of both in a well-balanced manner, the above ratio is preferably 3.0 or more, more preferably 3.5 or more. On the other hand, when it is desired to further improve the streak unevenness during film processing, the above ratio is preferably 8.0 or less, more preferably 7.5 or less.

In the methacrylic resin of the present embodiment, any combination of the above-mentioned (A) monomer, (B) monomer constituting the structural unit, (C) monomer, and (D) monomer is used. The total content of the specific component including the dimer, trimer and the like is preferably 0.01 to 0.40% by mass, with the methacrylic resin as 100% by mass. When it is 0.40% by mass or less, the amount of the oligomer component which is the coloring causative substance is reduced, so that a more excellent coloring suppressing effect can be obtained.
When the total content of the above components is within this range, the stickability to the mold or the film roll during the molding process can be suppressed, and the molding processability is improved. Further, if it is less than 0.01% by mass, the process becomes complicated, which is not preferable.
The total content of the above components can be determined as the total amount of the components detected in the retention time of 22 to 32 minutes when the measurement of gas chromatography / mass spectrometry (GC / MS) is performed.
The column preferably used in GC / MS measurement is preferably a non-polar or slightly polar column, and more preferably a column having (5% phenyl) -95% methylpolysiloxane as a stationary phase. Specifically, 007-2, CP-Sil 8CB, DB-5, DB-5.625, DB-5ht, HP-5, HP-5ms, OV®-5, PTE-5, PTE- 5QTM, PAS-5, RSL-200, Rtx®-5, Rtx®-5ms, SAC-5, SE®-54, SPB®-5, ULTRA-2, Examples thereof include XTI-5, SE (registered trademark) -52, BP-5, PE-2, ZB-5, AT (registered trademark) -5, EC (registered trademark) -5 and the like.
Helium gas is mentioned as a carrier gas preferably used. The gas flow rate is preferably about 1 mL / min, and is preferably controlled so as to be constant during the measurement.
The injection amount of the sample is preferably about 1 μL.
When octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate is used as the internal standard substance, it contains, for example, dimers and trimers of the monomer species used from a retention time of about 20 minutes. The peak of the component is observed, and the peak of the internal standard substance is detected with a retention time of about 35 minutes. The peaks of dimers and trimers are detected at a retention time shorter than the retention time of the internal standard substance. Here, the total content of the above components can be calculated from the area ratio of both peaks (that is, their abundance ratio) between the detection of the above components and the detection of the peaks of the internal standard substance. ..
In addition, the total content of the above components is more specifically determined by GC / MS measurement under specific devices and specific conditions described later in the examples.

<Glass transition temperature>
The glass transition temperature of the methacrylic resin of the present embodiment is preferably 115 ° C. or higher, more preferably 120 ° C. or higher, further 121 ° C. or higher, still more preferably 122 ° C. or higher, from the viewpoint of sufficiently obtaining heat resistance. It is more preferably 123 ° C. or higher, further preferably 124 ° C. or higher, and particularly preferably 125 ° C. or higher.
The glass transition temperature can be measured by the midpoint method in accordance with ASTM-D-3418, and specifically, can be measured by the method described in Examples described later.

<Melt flow rate>
The melt flow rate (MFR) of the methacrylic resin of the present embodiment may be 2 to 20 g / 10 minutes from the viewpoint of improving moldability in injection molding and enabling molding with a molded product having a complicated shape. It is preferable, more preferably 3 to 17 g / 10 minutes, still more preferably 5 to 14 g / 10 minutes.
The melt flow rate can be measured by the method described in Examples described later.

(Manufacturing method of methacrylic resin)
The method for producing the methacrylic resin of the present embodiment is not particularly limited as long as the above-mentioned methacrylic resin of the present embodiment can be obtained.
The methacrylic acid-based resin of the present embodiment includes a methacrylic acid ester monomer unit (A), a structural unit (B) having a ring structure in the main chain, a (meth) acrylic acid ester-based monomer unit (C), and If necessary, each monomer for forming another vinyl-based monomer unit (D) copolymerizable with the above-mentioned methacrylic acid ester monomer is used, and a bulk polymerization method, a solution polymerization method, or a suspension method is used. It can be produced by a turbid polymerization method, a precipitation polymerization method, or an emulsion polymerization method. For the production of the methacrylic resin, a massive polymerization method and a solution polymerization method are preferably used, and a solution polymerization method is more preferably used.
Further, the production of the methacrylic resin of the present embodiment may be a continuous type or a batch type.
Then, in the method for producing a methacrylic resin of the present embodiment, it is preferable to polymerize the monomer by radical polymerization.

Hereinafter, as an example of the method for producing the methacrylic resin of the present embodiment, a case of producing by radical polymerization in a batch method using a solution polymerization method will be specifically described.
An example of the method for producing a methacrylic resin of the present embodiment is a compounding step in which a monomer and an organic solvent are added to the reactor as needed, and a polymerization initiator is added to the reactor to form a monomer. Including a polymerization step of carrying out the polymerization reaction of the above, and if necessary, a devolatilization step of removing the organic solvent and the unreacted monomer.

((Mixing process))
In an example of the method for producing a methacrylic resin of the present embodiment, first, a monomer capable of forming a methacrylic acid ester monomer unit (A) and a structural unit (B) having a ring structure in the main chain are formed. A possible monomer, a monomer that can constitute the (meth) acrylic acid ester-based monomer unit (C), and if necessary, other vinyl-based singles copolymerizable with a methacrylic acid ester monomer. A monomer capable of forming the meth (D) and an organic solvent are prepared by a reactor (preparation step).

− Monomer −
As the monomer, each monomer unit (A) to (D) in the methacrylic resin of the present embodiment is as described.
The polymerization inhibitor may remain in the monomer used as long as it does not excessively interfere with the polymerization reaction, and the content of the remaining polymerization inhibitor is determined from the viewpoint of polymerization reactivity and handleability. The total amount of the total monomers is preferably 10 mass ppm or less, more preferably 5 mass ppm or less, and further preferably 3 mass ppm or less.

-Organic solvent-
The organic solvent used arbitrarily is preferably a good solvent of the methacrylic resin in consideration of the removal efficiency in the devolatilization step (described later) for removing the monomer remaining in the methacrylic resin. ..
The solubility parameter δ of the organic solvent is preferably 7.0 to 12.0 (cal / cm ³ ) ^1/2 , more preferably 8 in consideration of the solubility of the copolymer constituting the methacrylic resin. ^{.0~11.0 (cal / cm 3) 1/2} , still more preferably ^{8.2~10.5 (cal / cm 3) 1/2} .
The method for determining the value of the solubility parameter δ is described in, for example, P76-P118 in the non-patent document "Journal of Paint Technology Vol. 42, No. 541, February 1970". L. Hoy, "New Values of the Solubility Parameters From Vapor Pressure Data", J. Mol. You can refer to "Polymer Handbook Fourth Edition" by Brandrup et al., P-VII / 675-P714 and the like.
In addition, 1 (cal / cm ³ ) ^1/2 is about 0.489 (MPa) ^1/2 .
Specific examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene and mesitylene; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and decalin; and ketone solvents such as methylethylketone and methylisobutylketone. ..

Further, as the organic solvent, an organic solvent recovered in the devolatile step after polymerization can also be used.
When the recovered organic solvent contains an unreacted monomer component, the content of the unreacted monomer contained in the organic solvent is analyzed, and then only the required amount is used. Formulations can also be made by adding weights.

The amount of the organic solvent added in the polymerization step of the methacrylic resin of the present embodiment is preferably an amount that can be easily removed without causing precipitation of the copolymer or the monomer used during production due to the progress of polymerization. ..
When the methacrylic resin is polymerized by the solution polymerization method, the amount of the organic solvent to be blended is specifically 10 to 200 parts by mass when the total amount of all the monomers to be blended is 100 parts by mass. Is preferable. It is more preferably 25 to 200 parts by mass, further preferably 50 to 200 parts by mass, and even more preferably 50 to 150 parts by mass.

-Reactor-
The reactor may be appropriately selected in consideration of the amount of material and the size required from the viewpoint of heat removal.
The L / D of the reactor is preferably 0.5 to 50, more preferably 1 to 25, and even more preferably 1 to 10 from the viewpoint of stirring efficiency of the polymerization reaction solution.

Further, the amount of the monomer and / or the organic solvent to be provided to the reactor is not particularly problematic as long as the heat can be sufficiently removed, and the polymerization may be carried out in a full liquid, or 50 to 99% of the amount in the reactor is charged. It may be polymerized in an amount. Further, it may be refluxed at the time of polymerization.

The reactor is preferably equipped with a stirrer, and examples of the stirrer to be used include inclined paddle blades, flat paddle blades, propeller blades, anchor blades, Faudler blades (backward blades), and turbine blades. , Bull Margin Wings, Max Blend Wings, Full Zone Wings, Ribbon Wings, Supermix Wings, Intermig Wings, Special Wings, Axial Wings, etc., among others, Inclined Paddle Wings, Faudler Wings, Max Blend Wings, Full zone blades are preferably used.

The stirring speed at the time of polymerization depends on the type of stirring device used, the stirring efficiency of the stirring blade, the capacity of the polymerization tank, etc., but both the low viscosity state at the initial stage of polymerization and the high viscosity state at the late stage of polymerization are sufficiently stirred and mixed. The speed may be as high as possible, and in consideration of polymerization stability, it is preferably about 1 to 500 rpm.

The method for introducing each monomer into the reactor is not particularly limited as long as the effects of the present invention can be obtained, and even if they are mixed in advance and introduced into the reactor, they are separately introduced into the reactor. May be good. Considering productivity and handleability, it is preferable to mix some or all of the monomers in advance and then introduce them into the reactor.
In particular, when mixing in advance, some or all of the organic solvents that can be used in the polymerization can be mixed at the same time. When an organic solvent is used, it is preferable to use one that can dissolve the monomer to be polymerized, and the solubility parameter δ of the organic solvent is 7.0 to 12.0 (cal / cm ³ ). It is preferably ^1/2 .

In the compounding step, a molecular weight modifier and other additives (also used in the polymerization step described later) may be added in addition to the monomer and the organic solvent, if necessary, as long as the effects of the present invention can be exhibited. , Can be added in advance.

((Polymerization process))
In an example of the method for producing a methacrylic resin of the present embodiment, a polymerization initiator,, if necessary, a molecular weight modifier, other additives, and additional monomers are then added to the reactor after the preparation step. Then, the polymerization reaction of the monomer is carried out (polymerization step).

In this step, the polymerization reaction of the monomer is started by starting the addition of the polymerization initiator.
The polymerization initiator may be added to the reactor after being dissolved in an additional monomer and / or an additional organic solvent.

-Polymerization initiator-
The polymerization initiator used in the present embodiment may be one that decomposes at the polymerization temperature to generate active radicals, but it is necessary to achieve a required polymerization conversion rate within the residence time range, and polymerization is required. A polymerization initiator is selected that satisfies a half-life at temperature of 0.6 to 60 minutes, preferably 1 to 30 minutes. However, even for an initiator having a half-life of more than 60 minutes at the polymerization temperature, it is used as a polymerization initiator that generates an amount of active radicals suitable for the present embodiment by adding a predetermined amount in a batch or in a time of about 10 minutes. can do. In order to achieve the required polymerization conversion rate in that case, a polymerization initiator having a half-life at the polymerization temperature of 60 to 1800 minutes, preferably 260 to 900 minutes is selected.
The polymerization initiator preferably used can be appropriately selected in consideration of the polymerization temperature and the polymerization time. For example, Nippon Oil & Fats Co., Ltd. "Organic Peroxide" Material 13th Edition, Atchem Yoshitomi Co., Ltd. Technical Data And the initiator described in "Azo Polymerization Initiators" of Wako Pure Chemical Industries, Ltd. and the like can be preferably used, and the above-mentioned half-life can be easily determined by the various constants described.
The polymerization initiator is not limited to the following when radical polymerization is carried out, for example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butylper. Oxyneodecanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3 , 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane (eg, perhexa® C), acetyl peroxide, capriel peroxide, 2,4-dichlorobenzoyl peroxide , Isobutyl peroxide, acetylcyclohexylsulfonyl peroxide, t-butylperoxyviparate, t-butylperoxy-2-ethylhexanoate, iso-propylperoxydicarbonate, iso-butylperoxydicarbonate, sec- Butyl peroxy dicarbonate, n-butyl peroxy dicarbonate, 2-ethylhexyl peroxy dicarbonate, bis (4-t-butylcyclohexyl) peroxy dicarbonate, t-amylperoxy-2-ethylhexanoate, 1 , 1,3,3-Tetramethylbutylperoxyethyl hexanoate, 1,1,2-trimethylpropylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) hexane (eg, Perhexa® 25B), t-butylperoxyisopropyl monocarbonate, t-amylperoxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutylperoxyisopropyl monocarbonate, 1,1,2-trimethylpropylperoxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutylperoxyisononaate, 1,1,2-trimethylpropylperoxy-isononaate, t-butylperoxybenzoate Organic peroxides such as azobisisobutyronitrile, azobisisovaleronitrile, azobisdimethylvaleronitrile, azobiscyclohexanenitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2'- Azobis-4-methoxy-2,4-azobisisobutyronitrile, 2,2'-azobis -2,4-Dimethylvaleronitrile, 2,2'-azobis-2-methylbutyronitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), dimethyl-2,2'-azobisiso Examples thereof include general radical polymerization initiators such as azo compounds such as butyrate and 4,4'-azobis-4-cyanovaleric acid.
A combination of these radical polymerization initiators and an appropriate reducing agent may be used as a redox-based initiator.
These polymerization initiators can be used alone or in combination of two or more.

The polymerization initiator may be added in an amount necessary for obtaining a desired polymerization rate in the polymerization reactor.
In the polymerization reaction, the degree of polymerization can be increased by increasing the supply amount of the polymerization initiator, but the use of a large amount of the initiator tends to reduce the overall molecular weight and the calorific value during polymerization increases. Therefore, the polymerization stability may decrease due to overheating.
The polymerization initiator is preferably used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all the monomers used from the viewpoint of facilitating the acquisition of a desired molecular weight and ensuring the polymerization stability. , More preferably 0.001 to 0.8 parts by mass, and more preferably 0.01 to 0.5 parts by mass. The amount of the polymerization initiator added can be appropriately selected in consideration of the temperature at which the polymerization is carried out and the half-life of the initiator.

In the method for producing a methacrylic resin in the present embodiment, (a) the amount of oligomers (for example, dimers and trimers) and low molecular weights (for example, 500 to 10,000 in weight average molecular weight) produced in the late stage of polymerization. Radicals in the polymerization reaction system from the viewpoints of (b) increasing the polymerization conversion rate, (c) increasing the molecular weight of the obtained methacrylic resin, and (d) stabilizing the polymerization by suppressing overheating during polymerization. It is preferable that the amount is the optimum amount.
More specifically, in the embodiment of the present invention, the type of initiator is used so that the ratio of the total amount of radicals generated by the polymerization initiator to the total amount of unreacted monomers remaining in the reaction system is always equal to or less than a certain value. It is preferable to appropriately select the amount of the initiator, the polymerization temperature and the like.

Hereinafter, a method for adding a suitable polymerization initiator in the polymerization step will be described.
According to such a method, by controlling the amount of radicals generated during polymerization, the total amount of components in the methacrylic resin and the amount of components having a weight average molecular weight of 10,000 or less can be set in a desired range.

In the present embodiment, the total time from the start of addition of the polymerization initiator to the end of addition is defined as B time, and at least once per unit time of the polymerization initiator from the start of addition of the polymerization initiator to 0.5 × B hours. It is preferable that the addition amount of the above is smaller than the addition amount per unit time at the start of addition (condition (i)).

Here, in particular, from the viewpoint of optimizing the radical concentration, it is preferable to gradually reduce the addition rate.

Further, in the present embodiment, in addition to the above condition (i), the amount of the polymerization initiator added per unit time during the period of 0.01 × B to 0.3 × B from the start of addition of the polymerization initiator. Is preferably 70% or less (condition (ii)) of the addition amount per unit time at the start of addition, more preferably 60% or less, further preferably 50% or less, and 40%. The following is particularly preferable.
For example, when the rate of addition of the polymerization initiator (addition amount per unit time) at the start of polymerization is 100 ppm / hour, and the B time, which is the total time from the start of addition of the polymerization initiator to the end of addition, is 10 hours. In addition, it is preferable that the addition rate (addition amount per unit time) is 70 ppm / hour or less within 0.1 to 3 hours from the start of addition of the polymerization initiator.

More preferably, in the present embodiment, in addition to the above, the amount of the polymerization initiator added per unit time between 0.01 × B and 0.3 × B hours from the start of addition of the polymerization initiator. The average is preferably 70% or less, more preferably 60% or less, of the average amount of the polymerization initiator added per unit time from the start of addition of the polymerization initiator to 0.01 × B hours. It is preferably 50% or less, more preferably 40% or less, and particularly preferably 40% or less.

Then, in the present embodiment, in addition to the above condition (i), the amount of the polymerization initiator added per unit time is set between 0.7 × B and 1.0 × B hours from the start of addition of the polymerization initiator. The addition amount per unit time at the start of addition is preferably 25% or less (condition (iii)), more preferably 20% or less, and further preferably 18% or less.
For example, when the rate of addition of the polymerization initiator (addition amount per unit time) at the start of polymerization is 100 ppm / hour, and the B time, which is the total time from the start of addition of the polymerization initiator to the end of addition, is 10 hours. In addition, the addition rate (addition amount per unit time) is preferably 25 ppm / hour or less within 7 to 10 hours from the start of addition of the polymerization initiator.

More preferably, in the present embodiment, in addition to the above, the average amount of the polymerization initiator added per unit time between 0.7 × B and 1.0 × B hours from the start of addition of the polymerization initiator is calculated. The average amount of the polymerization initiator added per unit time from the start of addition of the polymerization initiator to 0.01 × B hours is preferably 25% or less, more preferably 20% or less. It is more preferably 18% or less.

It is more preferable that the above condition (iii) and the condition (iii) are adopted in combination.

Further, in the present embodiment, in addition to the above condition (i), the amount of the polymerization initiator added during the period of 0.5 × B to 1.0 × B from the start of addition of the polymerization initiator is set as the amount of the polymerization initiator. The total addition amount is preferably 20 to 80% by mass (condition (iv)), more preferably 20 to 70% by mass, and further preferably 20 to 60% by mass.

Further, in the present embodiment, in addition to the above condition (i), the polymerization reaction time for carrying out the polymerization reaction of the monomer is set to 1.0 × B to 5.0 × B time (condition (v)). Is preferable, 1.0 × B to 4.5 × B time is more preferable, and 1.0 × B to 4.0 × B time is further preferable.

It is more preferable that the above condition (iv) and the condition (v) are adopted in combination.

In any of the above cases (i) to (v), as a method of supplying the polymerization initiator, it is previously dissolved in the monomer and / or the organic solvent used in the polymerization reaction from the viewpoint of supply stability. It is preferable to supply the mixture after allowing it to grow. The monomer and / or organic solvent used is preferably the same as that used in the polymerization reaction. Further, from the viewpoint of avoiding blockage in the polymerization pipe, it is more preferable that the polymerization initiator is dissolved in an organic solvent and supplied.

-Molecular weight modifier-
Examples of the molecular weight adjusting agent used arbitrarily include a chain transfer agent and an inifata.
In the process for producing the methacrylic resin of the present embodiment, the molecular weight of the polymer to be produced can be controlled within a range that does not impair the object of the present invention.
As the chain transfer agent and the inifata, for example, a chain transfer agent such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine and the like; Control is possible, and further, the molecular weight can be controlled by adjusting the amount of these chain transfer agents and inifatas added.

When these chain transfer agents and inifatas are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability, and are not limited to the following, for example, n-butyl mercaptan and n-octyl mercaptan. , N-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylol propanthris (thioglycolate), pentaerythritol tetrakis (thioglycolate) ) Etc. can be mentioned.
These molecular weight adjusting agents can be appropriately added according to the required molecular weight, but are generally in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all the monomers used. Used.
In addition, other methods for controlling the molecular weight include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, a method of changing the polymerization temperature, and the like.
As these molecular weight control methods, only one kind of method may be used alone, or two or more kinds of methods may be used in combination.

In the methacrylic resin of the present embodiment, a chain transfer agent (molecular weight adjuster) may be used for the purpose of adjusting the molecular weight and improving the thermal stability of the polymer, and the chain transfer agent to be used may be used. As long as the effect of the present invention can be exhibited, the type and method of use thereof are not limited.
In the methacrylic resin of the present embodiment, it is necessary to control the total amount of the components including the dimer and the trimer to an appropriate amount, and from the viewpoint of controlling the amount of the component having a weight average molecular weight of 10,000 or less to an appropriate amount. It is preferable to select a method so that the amount of the remaining chain transfer agent does not become excessive with respect to the amount of the monomer remaining in the polymerization reaction system.
Examples of the method of supplying the chain transfer agent include a method in which the chain transfer agent is dissolved in a monomer in advance, a method in which the chain transfer agent is added all at once and / or sequentially at a stage where the degree of polymerization is 50% or less, and a method in which the degree of polymerization is up to 90%. A method such as a method of gradually reducing the amount of the chain transfer agent added can be preferably used by a method of adding the chain transfer agent in a batch and / or continuously.

-Other additives-
Other additives used arbitrarily are not particularly limited as long as the effects of the present invention can be exhibited, and may be appropriately selected depending on the intended purpose.

The dissolved oxygen concentration in the polymerization solution in the polymerization step is not particularly limited, but is preferably 10 ppm or less.
The dissolved oxygen concentration can be measured using, for example, a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.).
As a method for lowering the dissolved oxygen concentration, a method of bubbling an inert gas in the polymerization solution and an operation of pressurizing the inside of the container containing the polymerization solution with the inert gas to about 0.2 MPa and then releasing the pressure are repeated before the polymerization. Examples thereof include a method and a method of passing an inert gas into a container containing a polymerization solution.

The polymerization temperature when the methacrylic resin is produced by solution polymerization is not particularly limited as long as the polymerization proceeds, but from the viewpoint of productivity, it is preferably 50 to 200 ° C., more preferably 80 to 200 ° C. ° C., more preferably 80 to 180 ° C., even more preferably 80 to 160 ° C., and particularly preferably 90 to 160 ° C.

The polymerization reaction time is not particularly limited as long as the required degree of polymerization can be obtained, but from the viewpoint of productivity and the like, it is preferably 0.5 to 15 hours, more preferably 1 to 12 hours. Time, more preferably 1-10 hours.
The polymerization reaction time is the time from the start of addition of the polymerization initiator to the termination of the polymerization reaction, or from the start of addition of the polymerization initiator to the start of removal of the polymerization reaction solution from the reactor. Say time.

As a method for terminating the polymerization reaction of the monomer in the polymerization step, a known method may be appropriately selected according to the reaction system.

((Devolatile process))
From the polymerization reaction product extracted from the polymerization reactor, the organic solvent and the unreacted monomer can be removed by using a devolatilizer. The removed solvent may be reused in the polymerization reaction after performing a rectification operation.
The devolatilizer that can be suitably used in the present invention may be any device that can heat-treat the polymerization reaction product at a temperature of 150 to 320 ° C. and separate and recover the volatile matter.
Examples thereof include an extruder having one or a plurality of vent ports, an SC processor, a KRC kneader, a vacuum decompression tank with a gear pump, a thin film evaporator for high viscosity EXEVA, a flash drum, and the like.
The above-mentioned devolatilization device can be used alone or in combination of two or more kinds of devices.
In the present invention, it is preferable that the total amount of residual volatile matter contained in the resin after volatilization in the devolatile step is 1% by mass or less.

The methacrylic resin of the present embodiment can be produced by the production method described above.

(Methacrylic resin composition)
The methacrylic resin composition of the present embodiment is characterized by containing the above-mentioned methacrylic resin, and in addition to this, a rubber polymer, a resin other than the methacrylic resin, and other resins. It may contain an additive.

-Rubber polymer-
The rubbery polymer may be contained in the methacrylic resin composition of the present embodiment in a range not exceeding 3.5 parts by mass with respect to 100 parts by mass of the methacrylic resin. By containing a rubber polymer of preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, the film suppresses sticking to the roll during film molding. The effect of rubber is obtained. By containing a rubbery polymer of 3.5 parts by mass or less, preferably 3.0 parts by mass or less, the optical properties of the resin can be maintained.

The rubbery polymer is not particularly limited as long as it can exhibit the above effects, and known materials can be used.
For example, rubber particles having a multi-layer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluororubber can be used.
When high transparency is required for the film of the present embodiment, a rubbery polymer having a refractive index close to that of the above-mentioned methacrylic resin can be preferably used, and an acrylic rubbery polymer is particularly preferably used. be able to.

The rubbery polymer preferably used in the present embodiment is not limited to the following, but for example, the acrylic rubbery polymer proposed in Examples 1 to 3 below may be applied. Can be done.

-Example 1: Rubber polymer disclosed in Japanese Patent Publication No. 60-17406-
The rubbery polymer of Example 1 is a multilayer structure particle produced by the following steps (A) to (C).
(A) Step: A dispersion liquid of a polymer mainly composed of methyl methacrylate having a glass transition point of 25 ° C. or higher by emulsion polymerization of methyl methacrylate alone or a mixture of methyl methacrylate and a copolymerizable monomer thereof. First layer forming step to obtain.
Step (B): An alkyl acrylate that forms a copolymer having a glass transition point of 25 ° C. or lower when polymerized on the product obtained in the step (A), and a monomer copolymerizable therewith. A second layer step in which a mixture containing a polyfunctional cross-linking agent and a polyfunctional graft agent containing 0.1 to 5% by mass based on the total mass of the mixture is added and emulsion-polymerized.
Step (C): A chain of methyl methacrylate or a monomer mixture mainly composed of methyl methacrylate, which forms a polymer having a glass transition point of 25 ° C. or higher when polymerized on the product obtained by the step (B). A third layer forming step in which the transferant is emulsion-polymerized in multiple stages while increasing the amount in stages.
The multilayer structure particles are multilayer structure particles made of acrylic rubber in which the molecular weight of the third layer gradually decreases from the inside to the outside.

-Example 2: Rubber polymer disclosed in JP-A-8-245854-
The rubbery polymer of Example 2 is the following acrylic multilayer structure polymer powder.
In this acrylic multilayer structure polymer powder, the melting start temperature of the polymer is 235 ° C. or higher. The inner layer contains a polymer having a glass transition temperature Tg of 25 ° C. or lower when polymerized alone, and the inner layer is at least one soft polymer layer. The outermost layer is a hard polymer layer containing a polymer having a Tg of 50 ° C. or higher when polymerized alone.
The rubber polymer of Example 2 is an acrylic multilayer polymer powder containing a coagulating powder obtained by coagulating an emulsified latex of an acrylic multilayer polymer, and is a fine powder having a particle size of 212 μm or less of the coagulated powder after drying. The ratio is 40% by mass, and the void volume having a pore size of 5 μm or less measured by the mercury press-fitting method of the coagulated powder after drying is 0.7 cc or less per unit area.

-Example 3: Rubber polymer disclosed in Japanese Patent Publication No. 7-68318-
The rubbery polymer of Example 3 is a multilayer structure acrylic polymer satisfying the following requirements (a) to (g).
That is, the multilayer structure acrylic polymer is
(A) 90 to 99% by mass of methyl methacrylate, 1 to 10% by mass of an alkyl acrylate having 1 to 8 carbon atoms of an alkyl group, and allyl, metalyl, or clothi of an α, β-unsaturated carboxylic acid copolymerizable with these. The innermost hard layer polymer obtained by polymerizing a monomer mixture consisting of 0.01 to 0.3% by mass of a graft-binding monomer composed of at least one selected from the group consisting of allyl esters, 25 to 45 mass by mass. %When,
(B) In the presence of the innermost hard layer polymer, 70 to 90% by mass of n-butyl acrylate, 10 to 30% by mass of styrene, and allyl, metharyl of α, β-unsaturated carboxylic acid copolymerizable with these. Alternatively, 35 to 45 mass by mass of a soft layer polymer obtained by polymerizing a monomer mixture consisting of 1.5 to 3.0 mass% of a graft-binding monomer composed of at least one selected from the group consisting of crotyl esters. %When,
(C) In the presence of the innermost hard layer polymer and the soft layer polymer, 90 to 99% by mass of methyl methacrylate and 1 to 10% by mass of a monomer having 1 to 8 carbon atoms of an alkyl group. It is composed of 20 to 30% by mass of the outermost hard layer polymer obtained by polymerizing the mixture.
(D) The mass ratio of the soft layer polymer / (innermost hard layer polymer + soft layer polymer) is 0.45 to 0.57.
(E) A multi-layer acrylic polymer having an average particle size of 0.2 to 0.3 μm, when the multi-layer acrylic polymer is further separated by acetone.
(F) The graft ratio is 20 to 40% by mass,
(G) A multi-layer acrylic polymer having a tensile elastic modulus of 1000 to 4000 kg / cm ² of the acetone-insoluble portion.

In addition, examples of the rubbery polymer include the following particles.
For example, Japanese Patent Publication No. 55-27576, Japanese Patent Publication No. 58-1694, Japanese Patent Publication No. 59-36645, Japanese Patent Publication No. 59-36646, Japanese Patent Publication No. 62-42141, Japanese Patent Application Laid-Open No. 59-20221 , JP-A-63-27516, JP-A-51-129449, JP-A-52-56150, JP-A-50-124647, etc., Acrylic rubber having a 3- to 4-layer structure. Particles and the like can also be used.

The rubbery polymer contained in the methacrylic resin composition of the present embodiment preferably has a multilayer structure.
When the rubbery polymer has a multilayer structure, the larger the number of layers of the rubbery polymer, the more the elasticity can be controlled in a suitable range, but the rubbery polymer is contained. Considering the color tone of the film in the case, the particles having a three-layer structure or more are preferable, and the acrylic rubber particles having a three-layer structure or more are more preferable.
By using rubber particles having a three-layer structure or more as the rubber polymer, thermal deterioration during molding of the film of the present embodiment and deformation of the rubber polymer due to heating are suppressed, and the heat resistance of the film is improved. Transparency tends to be maintained.

A rubbery polymer having a three-layer structure or more refers to rubber particles having a structure in which a soft layer made of a rubber-like polymer and a hard layer made of a glassy polymer are laminated, and the hard layer (first layer) -soft layer from the inside. A preferable example is a particle having a three-layer structure formed in the order of (second layer) -hard layer (third layer).
By having the hard layer in the innermost layer and the outermost layer, the deformation of the rubbery polymer tends to be suppressed, and by having the soft component in the central layer, good toughness tends to be imparted.

The rubbery polymer composed of three layers can be formed, for example, by a multilayer structure graft copolymer. The multilayer structure graft copolymer can be produced, for example, by using methyl methacrylate and a monomer copolymerizable with the methyl methacrylate.
The monomer copolymerizable with the methyl methacrylate is not limited to the following, but for example, known (meth) acrylic acid, (meth) acrylate other than methyl methacrylate, styrene, α-methylstyrene and the like. Monofunctional monomer, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, triallyl Examples thereof include polyfunctional monomers such as isocyanurate, diallyl maleate, and divinylbenzene.
The above-mentioned monomers may be used alone or in combination of two or more, if necessary.

Specifically, when the rubbery polymer has a three-layer structure, the copolymer forming the innermost layer contains 65 to 90% by mass of methyl methacrylate and other copolymerizable copolymerizers thereof. It is preferably a copolymer using 10 to 35% by mass of the monomer.
From the viewpoint of appropriately controlling the refractive index of the copolymer, the other copolymerizable monomer copolymerizable with the methyl methacrylate is 0.1 to 5% by mass of the acrylic acid ester monomer. , 5 to 35% by mass of the aromatic vinyl compound monomer and 0.01 to 5% by mass of the copolymerizable polyfunctional monomer are preferable.
The acrylic acid ester monomer (forming the innermost layer in the copolymer) is not particularly limited, but for example, n-butyl acrylate and 2-hexyl acrylate are preferable.
As the aromatic vinyl compound monomer, the same monomer as that used for the methacrylic resin can be used, but preferably, the refractive index of the innermost layer is adjusted to obtain the film of the present embodiment. From the viewpoint of improving transparency, styrene or a derivative thereof is used.
The copolymerizable polyfunctional monomer is not particularly limited, but is preferably ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1, Examples thereof include 4-butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, and divinylbenzene. Only one of these may be used alone, or two or more thereof may be used in combination. Of these, allyl (meth) acrylate is more preferred.

The second layer of the rubbery polymer composed of three layers, that is, the soft layer, is a rubber-like copolymer exhibiting rubber elasticity and is important for imparting excellent impact strength to the film.
The second layer is preferably formed from, for example, a copolymer of an alkyl acrylate and a monomer copolymerizable with the alkyl acrylate, or a polymer of a copolymerizable polyfunctional monomer.
The alkyl acrylate is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. These can be used alone or in combination of two or more, and in particular, n-butyl acrylate and 2-ethylhexyl acrylate are preferable.
Further, the other monomer copolymerizable with these alkyl acrylates is not particularly limited, and a general monomer can be used, but a methacrylic resin is prepared by adjusting the refractive index of the second layer. Styrene or a derivative thereof is preferably used from the viewpoint of improving the transparency by adjusting to.
The copolymerizable polyfunctional monomer is not particularly limited, but is preferably ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1, Examples thereof include 4-butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, and divinylbenzene. Only one of these may be used alone, or two or more thereof may be used in combination.

When the rubbery polymer has a three-layer structure, the outermost layer contains 70 to 100% by mass of methyl methacrylate and 0 to 30% by mass of another copolymerizable monomer copolymerizable therewith. It is preferably formed of a copolymer.
The other copolymerizable monomer copolymerizable with methyl methacrylate forming the outermost layer is not particularly limited, and examples thereof include n-butyl acrylate and 2-hexyl acrylate. ..

When the rubbery polymer is composed of three layers, the rubbery polymer may contain a rubbery polymer having a crosslinked structure, and the rubbery polymer having the crosslinked structure is contained in the second layer. It is preferable that the rubber is used.
The rubber-like polymer is obtained by copolymerizing a polyfunctional monomer, and a crosslinked structure can be formed in the polymer. The crosslinked structure in the rubbery polymer imparts appropriate rubber elasticity and can retain its form in a dispersed state without being dissolved in the monomer mixture.
As the polyfunctional monomer for forming the crosslinked structure, a compound copolymerizable with methyl methacrylate and methyl acrylate can be used.
The amount of the polyfunctional monomer used is preferably 0.1 to 5% by mass with respect to the entire second layer. When the amount used is 0.1% by mass or more, a sufficient cross-linking effect can be obtained, and when it is 5% by mass or less, an appropriate cross-linking strength and an excellent rubber elastic effect can be obtained. Further, when the amount of the polyfunctional monomer used is 0.1% by mass or more, the rubber-like polymer does not dissolve or swell even when the cast polymerization step is carried out, and the form of the rubber-like elastic body is formed. Can be retained.

Further, in the second layer, it is preferable to use a polyfunctional graft agent for forming a graft bond that makes the affinity with the polymer of the third layer described later close.
The polyfunctional graft agent is a polyfunctional monomer having a different functional group, and is not limited to the following, and examples thereof include allyl esters such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Of these, allyl acrylate and allyl methacrylate are preferable.
The amount of the polyfunctional grafting agent used is preferably in the range of 0.1 to 3% by mass with respect to the entire second layer. When the amount of the polyfunctional grafting agent used is 0.1% by mass or more, a sufficient grafting effect can be obtained, and when it is 3% by mass or less, a decrease in rubber elasticity can be prevented.

In the polymerization of the third layer (outermost layer), the molecular weight can be adjusted by using a chain transfer agent in order to improve the affinity with the methacrylic resin.

Further, in order to improve the transparency of the film of the present embodiment, it is necessary to match the refractive indexes of the dispersed rubber polymer and the methacrylic resin. However, as described above, when alkyl acrylate is used as a main component in the second layer, it is extremely difficult to completely match the refractive index of the second layer with the methacrylic resin. In order to match the refractive index, for example, when the alkyl acrylate and styrene or a derivative thereof are copolymerized in the second layer, the refractive index becomes substantially equal in a certain temperature range and the transparency is improved, but when the temperature is changed, The refractive index shifts and the transparency deteriorates.
As a means for avoiding this, there is a method of providing a first layer having a refractive index almost the same as that of the methacrylic resin. Further, reducing the thickness of the second layer is also an effective method for preventing deterioration of the transparency of the film of the present embodiment.

The average particle size of the rubbery polymer is preferably 0.03 to 1 μm from the viewpoint of imparting impact strength to the film of the present embodiment, from the viewpoint of surface smoothness, and from the viewpoint of obtaining a desired film thickness. , More preferably 0.05 to 0.7 μm, still more preferably 0.05 to 0.5 μm, even more preferably 0.05 to 0.4 μm, even more preferably 0.05 to 0.3 μm. ..
When the average particle size of the rubbery polymer is 0.03 μm or more, sufficient impact strength tends to be obtained in the film of the present embodiment, and when it is 1 μm or less, the surface of the film of the present embodiment is fine. Mirror surface properties can be obtained by preventing the appearance of rippled defects, and in the case of heat molding, a decrease in surface gloss can be suppressed in the stretched portion, and transparency can be ensured.

As a method for measuring the average particle size of the rubbery polymer, a conventionally known method can be used, and examples thereof include the methods shown in (1) and (2) below.
(1) After cutting out a portion of the molded article of the methacrylic resin composition in the circular saw, to prepare a sample for observation with RuO 4 _(ruthenium acid) stained ultramicrotomy, manufactured by Hitachi, Ltd. of Co. The cross section of the stained rubber particles is observed using a transmission electron microscope (model: H-600 type), and then an image is taken. The average particle diameter of rubber particles is obtained by measuring the diameters of 20 typical particles printed at high magnification on a scale and obtaining the average value of the particle diameters.
(2) The emulsion of the rubbery polymer was sampled, diluted with water so as to have a solid content of 500 ppm, and the absorbance at a wavelength of 550 nm was measured using a UV1200V spectrophotometer (manufactured by Shimadzu Corporation). From this value, the average particle size of a sample whose particle size has been measured from a transmission electron micrograph is obtained by using a calibration curve prepared by similarly measuring the absorbance.
In the measurement methods (1) and (2) above, substantially the same particle size measurement value can be obtained.

The difference between the refractive index of the methacrylic resin and the refractive index of the rubbery polymer is 0.03 or less from the viewpoint of transparency and the temperature dependence of transparency in the film of the present embodiment. It is preferable, more preferably 0.025 or less, still more preferably 0.02 or less.

Examples of the method for producing a rubbery polymer include emulsion polymerization.
Specifically, when the rubbery polymer is composed of three layers as described above, in the presence of an emulsifier and a polymerization initiator, the first layer of the monomer mixture is first added to complete the polymerization. Next, the polymer mixture (particles) is easily latexed by adding the second layer monomer mixture to complete the polymerization, and then adding the third layer monomer mixture to complete the polymerization. Can be obtained as.
This rubbery polymer can be recovered as a powder from latex by a known method such as salting out, spray drying, and freeze drying.
When the rubbery polymer is a polymer composed of three layers, it is possible to avoid agglomeration of particles of the rubbery polymer by providing a hard layer in the third layer.

-Other resins-
The methacrylic resin composition of the present embodiment may contain a combination of other resins in addition to the methacrylic resin and the rubbery polymer described above.
As the other resin, a known thermoplastic resin can be used as long as it can exhibit the characteristics required for the methacrylic resin composition of the present embodiment.
The thermoplastic resin is not limited to the following, but is not limited to, for example, polyethylene-based resin, polypropylene-based resin, polystyrene-based resin, syndiotactic polystyrene-based resin, polycarbonate-based resin, ABS resin, acrylic-based resin, AS. Resins, BAAS resins, MBS resins, AAS resins, biodegradable resins, polycarbonate-ABS resin alloys, polyalkylene allylate resins (polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, etc.) , Polyene-based resin, polyphenylene ether-based resin, polyphenylene sulfide-based resin, phenol-based resin and the like.
In particular, AS resin and BAAS resin are preferable from the viewpoint of improving fluidity, ABS resin and MBS resin are preferable from the viewpoint of improving impact resistance, and polyester resin is preferable from the viewpoint of improving chemical resistance. Further, polyphenylene ether-based resin, polyphenylene sulfide-based resin, phenol-based resin and the like are preferable from the viewpoint of improving flame retardancy. Polycarbonate-based resins are preferable when it is necessary to impart heat resistance, impact resistance, or adjust optical characteristics. Further, the acrylic resin has good compatibility with the above-mentioned methacrylic resin, and is preferable when adjusting characteristics such as fluidity and impact resistance while maintaining transparency.
As the various thermoplastic resins, only one type may be used alone, or two or more types of resins may be used in combination.

In the methacrylic resin composition of the present embodiment, when the above-mentioned methacrylic resin and the other resin are used in combination, the effect of the present invention may be exhibited as long as the effect of the present invention can be exhibited. In consideration, the blending ratio of the other resin is 95% by mass or less when the general-purpose acrylic resin is blended as the other resin with respect to 100% by mass of the total amount of the above-mentioned methacrylic resin and the other resin. It is more preferably 85% by mass or less, still more preferably 80% by mass or less, still more preferably 75% by mass or less; and when a resin other than the acrylic resin is blended as another resin. The total amount of the above-mentioned methacrylic resin and other resins is 100% by mass, preferably 50% by mass or less, more preferably 45% by mass, still more preferably 40% by mass or less, still more. It is preferably 30% by mass or less, and even more preferably 20% by mass or less.
Further, in consideration of the effect of imparting characteristics when blending other resins, the lower limit of the blending amount when blending other resins is preferably 0.1% by mass or more, more preferably 1% by mass or more, and further. It is preferably 2% by mass or more, even more preferably 3% by mass or more, and even more preferably 5% by mass or more.
The type and content of the other resin can be appropriately selected according to the effect expected when used in combination with the other resin.

-Additives-
A predetermined additive may be added to the methacrylic resin composition of the present embodiment in order to impart various properties such as rigidity and dimensional stability.
The additives are not limited to the following, but are, for example, various stabilizers such as an ultraviolet absorber, a heat stabilizer, and a light stabilizer; plastic agents (paraffin-based process oil, naphthenic-based process oil, aromatic-based). Process oil, paraffin, organic polysiloxane, mineral oil); Flame retardant (eg, organic phosphorus compound, red phosphorus, phosphorus such as inorganic phosphate, halogen, silica, silicone, etc.); Flame retardant aid (For example, antimonides oxide, metal oxides, metal hydroxides, etc.); Hardeners (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, 3,9-bis (3-aminopropyl) ) -2,4,8,10-Tetraoxaspiro [5,5] Undecane, Mensendiamine, Isophoronediamine, N-aminoethylpiperazin, m-xylenediamine, m-fehyrenideamine, diaminophenylmethane, diaminodiphenyl Aminates such as sulfone, dicyandiamide, dihydrazide adipate, phenolic resins such as phenol novolac resin and cresol novolac resin, polymercaptans such as liquid polymercaptan and polysulfide, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, methylcyclohexenetetracarboxylic anhydride, succinic anhydride, trimellitic anhydride, chlorendic anhydride, benzophenonetetracarboxylic acid Acid anhydrides, acid anhydrides such as ethylene glycol bis (anhydrotrimate), etc.); Hardening accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2) -Imidazoles such as undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, organic phosphines such as triphenylphosphine and tributylphosphine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, 2, Tertiary amines such as 4,6-tris (diaminomethyl) phenol and tetramethylhexanediamine, boron salts such as triphenylphosfine tetraphenylborate, tetraphenylphosphonium tetraphenylborate, and triethylamine tetraphenylborate, 1,4- Benzo Kinoid compounds such as quinone, 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-1,4-benzoquinone, etc.); Antistatic agents (eg, , Polyamide elastomer, quaternary ammonium salt system, pyridine derivative, aliphatic sulfonate, aromatic sulfonate, aromatic sulfonate copolymer, sulfate ester salt, polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide , Polyalkylene glycol derivatives, betaine-based, imidazoline derivatives, etc.); Conductivity-imparting agents; Stress relievers; Mold release agents (alcohols and esters of alcohol and fatty acids, esters of alcohol and dicarboxylic acids, silicone oil, etc.); Crystallization accelerator; hydrolysis inhibitor; lubricant (for example, higher fatty acids such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and metal salts thereof, higher fatty acids such as ethylene bisstearoamide). Azos, etc.); Impact-imparting agents; Sliding improvers (hydrocarbons such as low molecular weight polyethylene, higher alcohols, polyhydric alcohols, polyglycols, polyglycerols, higher fatty acids, higher fatty acid metal salts, fatty acid amides, fatty acids, etc. Esters with aliphatic alcohols, full esters or partial esters of fatty acids and polyhydric alcohols, full esters or partial esters of fatty acids and polyglycols, silicones, fluororesins, etc.); compatibilizers; nucleating agents; fillers, etc. Reinforcer; Flow conditioner; Dyes (nitroso dye, nitro dye, azo dye, stillben azo dye, ketoimine dye, triphenylmethane dye, xantene dye, acrydin dye, quinoline dye, methine / polymethine dye, thiazole dye, indamine / Indophenol dyes, azine dyes, oxazine dyes, thiazine dyes, sulfide dyes, aminoketone / oxyketone dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, etc.); sensitizers; colorants (titanium oxide, carbon black, titanium yellow, etc.) Inorganic pigments such as iron oxide pigments, ultramarine blue, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium pigments, azo lake pigments, benzimidazolone pigments, dialylide pigments, condensed azo pigments and other azo pigments, Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, isoindolinone pigments, quinophthalone pigments, quinac Organic pigments such as lidone pigments, perylene pigments, anthraquinone pigments, perinone pigments, condensed polycyclic pigments such as dioxazine violet, lint-like aluminum metallic pigments, spherical pigments used to improve weld appearance. Aluminum pigments, mica powders for pearl-like metallic pigments, and other metallic pigments such as glass and other inorganic polyhedron particles coated with metal plating or sputtering); thickeners; anti-settling agents; anti-sagging agents; fillers (Fibrous reinforcing agents such as glass fibers and carbon fibers, as well as glass beads, calcium carbonate, talc, clay, etc.); Defoamers (silicone defoamers, surfactants, polyethers, organic materials such as higher alcohols, etc.) Antifoaming agent, etc.); Coupling agent; Light-diffusing fine particles; Anti-rust agent; Antibacterial / antifungal agent; Antifouling agent; Conductive polymer, etc.

--Light diffusing fine particles ---
The light diffusing fine particles are not limited to the following, but are, for example, inorganic fine particles such as alumina, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide, and glass beads, styrene crosslinked beads, MS crosslinked beads, and siloxane. Examples thereof include organic fine particles such as system-crosslinked beads. Further, hollow crosslinked fine particles made of a highly transparent resin material such as an acrylic resin, a polycarbonate resin, an MS resin, and a cyclic olefin resin, hollow fine particles made of glass, and the like can also be used as light diffusing fine particles.
As the inorganic fine particles, alumina, titanium oxide and the like are more preferable from the viewpoint of diffusibility and availability.
Further, as the light diffusing fine particles, only one type may be used alone, or two or more types may be used in combination.

Here, the refractive index of the light diffusing fine particles is preferably 1.3 to 3.0, more preferably 1.3 to 2.5, and even more preferably 1.3 to 2.0. When the refractive index is 1.3 or more, practically sufficient scattering property is obtained in the film of the present embodiment, and when it is 3.0 or less, the film of the present embodiment is used for a member near the lamp. At this time, it is possible to suppress scattering in the vicinity of the lamp and effectively prevent the occurrence of uneven brightness and uneven emission light color tone.
The refractive index is a value at a temperature of 20 ° C. based on the D line (589 nm). As a method for measuring the refractive index of light-diffusing fine particles, for example, the light-diffusing fine particles are immersed in a liquid whose refractive index can be changed little by little, and the interface of the light-diffusing fine particles is observed while changing the refractive index of the liquid. However, there is a method of measuring the refractive index of the liquid when the interface of the light diffusing fine particles becomes unclear. An Abbe refractometer or the like can be used to measure the refractive index of the liquid.

The average particle size of the light diffusing fine particles is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, still more preferably 0.3 to 10 μm, and even more preferably 0.4 to 5 μm. ..
When the average particle size is 20 μm or less, light loss due to backward reflection or the like is suppressed, and the incoming light can be efficiently diffused to the light emitting surface side, which is preferable. Further, when the average particle size is 0.1 μm or more, the emitted light can be diffused, and desired surface emission brightness and diffusivity can be obtained, which is preferable.

Further, the content of the light diffusing fine particles in the methacrylic resin composition of the present embodiment is 0 with respect to 100 parts by mass of the methacrylic resin from the viewpoint of exhibiting the light diffusing effect and the uniformity of surface emission. It is preferably .0001 to 0.03 parts by mass, more preferably 0.0001 to 0.01 parts by mass.

--Heat stabilizer ---
Examples of the heat stabilizer include, but are not limited to, hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. The methacrylic resin of the present embodiment is suitably used in various applications such as melt extrusion, injection molding, and film molding. The heat history received during processing varies depending on the processing method, but it ranges from several tens of seconds like an extruder to tens of minutes to several hours of heat history such as thick product molding and sheet molding. There are various.
When receiving a long heat history, it is necessary to increase the amount of the heat stabilizer added in order to obtain the desired heat stability. From the viewpoint of suppressing bleed-out of the heat stabilizer and preventing the film from sticking to the roll during film formation, it is preferable to use a plurality of types of heat stabilizers in combination. For example, a phosphorus-based antioxidant and a sulfur-based antioxidant are used. It is preferable to use at least one selected from the agents in combination with a hindered phenol-based antioxidant.
These antioxidants may be used alone or in combination of two or more.

The heat stabilizer is not limited to the following, but is, for example, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3-( 3,5-Di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,3', 3'', 5 , 5', 5''-hexa-tert-butyl-a, a', a''-(mesitylen-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -O-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylene bis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylene Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3 , 5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1, 3,5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine -2-Ilamine) phenol, 2-[1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, 2-tert-acrylate Examples thereof include butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl.
In particular, pentaerythritol terakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2-[1- (2-Hydroxy-3,5-di-tert-pentylphenyl) ethyl acrylate] -4,6-di-tert-pentylphenyl is preferred.

Further, as the hindered phenol-based antioxidant as the heat stabilizer, a commercially available phenol-based antioxidant may be used, and such a commercially available phenol-based antioxidant is limited to the following. However, for example, Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by BASF), Irganox 1076 (Irganox 1076): Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, manufactured by BASF), Irganox 1330 (Irganox 1330: 3,3', 3'', 5,5', 5''-Hexa-t-butyl-a,a',a''-(mesitylen-2,4,6-triyl) tri-p-cresol, manufactured by BASF), Irganox 3114 (Irganox 3114: 1,3,5) -Tris (3,5-di-t-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trion, manufactured by BASF), Irganox 3125 (Irganox 3125, manufactured by BASF), Adecastab AO-60 (pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by ADEKA), Adecastab AO-80 (3) , 9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionylxyoxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] Undecan, manufactured by ADEKA), Sumilyzer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilyzer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Smilizer GS (Sumilizer GS: 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, manufactured by Sumitomo Chemical Co., Ltd., Sumilizer GM (Sumilizer) GM: 2-tert-butyl-4-methyl-6- acrylate (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl, manufactured by Sumitomo Chemical Co., Ltd.), vitamin E (manufactured by Eisai) and the like.
Among these commercially available phenolic antioxidants, Irganox 1010, Adecastab AO-60, Adecastab AO-80, Irganox 1076, Sumilyzer GS and the like are preferable from the viewpoint of the effect of imparting thermal stability to the resin.
These may be used alone or in combination of two or more.

The phosphorus-based antioxidant as the heat stabilizer is not limited to the following, but is, for example, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-). Bis (1,1-dimethylethyl) -6-methylphenyl) Ethyl ester phosphite, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4'-diylbisphos Phonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4) -Dicumylphenyl) pentaerythritol-diphosphite, tetrakis (2,4-t-butylphenyl) (1,1-biphenyl) -4,4'-diylbisphosphonite, di-t-butyl-m-cresyl- Phenylonite, 4- [3-[(2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepine) -6-yloxy] propyl] -2 -Methyl-6-tert-butylphenol and the like can be mentioned.
Further, a commercially available phosphorus-based antioxidant may be used as the phosphorus-based antioxidant, and such a commercially available phosphorus-based antioxidant is not limited to the following, but is, for example, Irgaphos 168 ( Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite, manufactured by BASF), Irgafos 12: Tris [2-[[2,4,8,10-tetra-t-butyldibenzo [] d, f] [1,3,2] dioxaphosfefin-6-yl] oxy] ethyl] amine, manufactured by BASF), Irgafos 38: bis (2,4-bis (1,1-dimethyl) Ethyl) -6-methylphenyl) ethyl ester phosphite, made by BASF), Adecastab 329K (ADK STAB-329K, made by ADEKA), Adecastab PEP-36 (ADK STAB PEP-36, made by ADEKA), Adecastab PEP-36A (made by ADEKA) ADK STAB PEP-36A, made by ADEKA), Adecastab PEP-8 (ADK STAB PEP-8, made by ADEKA), Adecaster HP-10 (ADK STAB HP-10, made by ADEKA), Adecastab 2112 (made by ADK STAB 2112, ADEKA) ), Adecastab 1178 (ADKA STAB 1178, made by ADEKA), Adecastab 1500 (ADK STAB 1500, made by ADEKA) Sandstab P-EPQ (made by Clariant), Weston 618 (made by Weston 618, GE), Weston 619G (made by Weston 618, Weston 619G) ), Ultranox 626 (manufactured by GE), Sumilizer GP: 4- [3-[(2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3]) 2] Dioxaphosfepine) -6-yloxy] propyl] -2-methyl-6-tert-butylphenol, manufactured by Sumitomo Chemical Co., Ltd.), HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10) -Oxide, manufactured by Sanko Co., Ltd.) and the like.
Among these commercially available phosphorus-based antioxidants, Irgafos 168, Adecastab PEP-36, Adecastab PEP-36A, Adecastab HP from the viewpoint of the effect of imparting thermal stability in the resin and the effect of combined use with various antioxidants. -10, Adecastab 1178 are preferable, and Adecastab PEP-36A and Adecastab PEP-36 are particularly preferable.
These phosphorus-based antioxidants may be used alone or in combination of two or more.

The sulfur-based antioxidant as the heat stabilizer is not limited to the following, but is, for example, 2,4-bis (dodecylthiomethyl) -6-methylphenol (Irganox 1726, BASF). , Irganox 1520L, manufactured by BASF), 2,2-bis {[3- (dodecylthio) -1-oxoporopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (adekastab AO-412S) , ADEKA Corporation), 2,2-bis {[3- (dodecylthio) -1-oxoporopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (Cheminox PLS, manufactured by Chemipro Kasei Kaisha, Ltd.), Di (tridecyl) 3,3'-thiodipropionate (AO-503, manufactured by ADEKA Corporation) and the like can be mentioned.
Among these commercially available sulfur antioxidants, Adecastab AO-412S and Cheminox PLS are preferable from the viewpoints of the effect of imparting thermal stability in the resin, the effect of being used in combination with various antioxidants, and the viewpoint of handleability.
These sulfur-based antioxidants may be used alone or in combination of two or more.

The content of the heat stabilizer may be an amount that can improve the heat stability, and if the content is excessive, problems such as bleeding out during processing may occur. It is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, further preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, and more preferably 0.8 parts by mass or less with respect to 100 parts by mass of the based resin. It is preferably 0.01 part by mass or more, preferably 0.01 to 0.8 part by mass, and particularly preferably 0.01 to 0.5 part by mass.

--Lubricant ---
Examples of the lubricant include, but are not limited to, fatty acid esters, fatty acid amides, fatty acid metal salts, hydrocarbon-based lubricants, alcohol-based lubricants, and the like.

The fatty acid ester that can be used as the lubricant is not particularly limited, and conventionally known fatty acid esters can be used.
Examples of the fatty acid ester include fatty acids having 12 to 32 carbon atoms such as lauric acid, palmitic acid, heptadecanoic acid, stearic acid, oleic acid, araquinic acid and behenic acid, and monovalents such as palmityl alcohol, stearyl alcohol and behenyl alcohol. Ester compounds with fatty alcohols, polyhydric alcohols such as glycerin, pentaerythritol, dipentaerythritol, and sorbitan, and composite esters of fatty acids, polybasic organic acids, and monovalent fatty alcohols or polyhydric alcohols. Compounds and the like can be used. Examples of such fatty acid ester-based lubricants include cetyl palmitate, butyl stearate, stearyl stearate, stearyl citrate, glycerin monocaprilate, glycerin monocaplate, glycerin monolaurate, glycerin monopalmitate, and glycerin dipalmi. Tate, glycerin monostearate, glycerin distearate, glycerin tristearate, glycerin monooleate, glycerin dioleate, glycerin trioleate, glycerin monolinoleate, glycerin monobehenate, glycerin mono12-hydroxystearate, glycerin Di12-hydroxystearate, glycerintri 12-hydroxystearate, glycerin diacet monostearate, glycerindic acid fatty acid ester, pentaerythritol adipic acid stearic acid ester, montanic acid partially saponified ester, pentaerythritol tetrastearate, dipenta Examples thereof include erythritol hexastearate and sorbitan tristearate.
These fatty acid ester-based lubricants can be used alone or in combination of two or more.
Examples of commercially available products include Riken Vitamin's Rikemar series, Poem series, Rikestar series, Rikemaster series, Kao's Exel series, Leodor series, Exepearl series, and Coconard series. Rikemar S-100, Rikemar H-100, Poem V-100, Rikemar B-100, Rikemar HC-100, Rikemar S-200, Poem B-200, Rikestar EW-200, Rikestar EW-400, Exel S -95, Leodor MS-50 and the like can be mentioned.

The fatty acid amide-based lubricant is also not particularly limited, and conventionally known ones can be used.
Examples of the fatty acid amide-based lubricant include saturated fatty acid amides such as lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide and hydroxystearic acid amide; and unsaturated fatty acid amides such as oleic acid amide, erucic acid amide and ricinolic acid amide. Fatty acid amides; substituted amides such as N-stearyl stealic acid amides, N-oleyl oleic acid amides, N-stearyl oleic acid amides, N-oleyl stealic acid amides, N-stearyl erucic acid amides, N-oleyl palmitate amides; methylol Methylolamides such as stearate amides and methylolbechenic acid amides; methylene bisstearic acid amides, ethylene biscapric acid amides, ethylene bislauric acid amides, ethylene bisstearic acid amides (ethylene bisstearyl amides), ethylene bisisostearic acid amides, ethylene Bishydroxystearic acid amide, ethylene bisbechenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbechenic acid amide, hexamethylene bishydroxystearic acid amide, N, N'-distearyl adipate amide, N, N'- Saturated fatty acid bisamides such as distearyl sevacinic acid amide; unsaturated fatty acids such as ethylene bisoleic acid amides, hexamethylene bisoleic acid amides, N, N'-diorail adipic acid amides, N, N'-diorail sevacinic acid amides. Bisamide; Examples thereof include aromatic bisamides such as m-xylylene bisstearic acid amide and N, N'-distearyl isophthalic acid amide.
These fatty acid amide-based lubricants can be used alone or in combination of two or more.
Commercially available products include, for example, Diamid series (manufactured by Nihon Kasei), Amide series (manufactured by Nihon Kasei), Nikka amide series (manufactured by Nihon Kasei), Methylol amide series, Bisamide series, Slipax series (Nihon Kasei). , Kao wax series (manufactured by Kao), fatty acid amide series (manufactured by Kao), ethylene bisstearic acid amides (manufactured by Dainichi Chemical Industry Co., Ltd.) and the like.

The fatty acid metal salt refers to a metal salt of a higher fatty acid, for example, lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinolate, strontium stearate, barium stearate, barium laurate, barium ricinolate, Zinc stearate, zinc laurate, zinc ricinolate, zinc 2-ethylhexoate, lead stearate, dibasic lead stearate, lead naphthenate, calcium 12-hydroxystearate, lithium 12-hydroxystearate and the like. Among them, calcium stearate, magnesium stearate, and zinc stearate are particularly preferable because the obtained transparent resin composition has excellent processability and extremely excellent transparency.
Examples of commercially available products include SZ series, SC series, SM series, and SA series manufactured by Sakai Chemical Industry Co., Ltd.
When the fatty acid metal salt is used, the blending amount is preferably 0.2% by mass or less from the viewpoint of maintaining transparency.

The above-mentioned lubricant may be used alone or in combination of two or more.

The lubricant used is preferably one having a decomposition start temperature of 200 ° C. or higher. The decomposition start temperature can be measured by the 1% weight loss temperature by TGA.

The content of the lubricant may be an amount that can be effective as a lubricant, and if the content is excessive, problems such as bleed-out during processing and extrusion failure due to screw slippage may occur. Therefore, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, and even more preferably 0.8 parts by mass or less with respect to 100 parts by mass of the methacrylic resin. It is even more preferably 0.01 to 0.8 parts by mass, and particularly preferably 0.01 to 0.5 parts by mass. When the amount is added in the above range, the decrease in transparency due to the addition of the lubricant is suppressed, the adhesion to the metal roll tends to be suppressed during film formation, and the secondary to the film such as primer coating is suppressed. It is preferable because problems such as peeling are unlikely to occur in a long-term reliability test after processing.

--UV absorber ---
The ultraviolet absorber is not limited to the following, but includes, for example, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, and the like. Examples thereof include malonate-based compounds, cyanoacrylate-based compounds, lactone-based compounds, salicylic acid ester-based compounds, and benzoxadinone-based compounds.

Examples of benzotriazole compounds include 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-yl) phenol], 2- (3). 5-Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazole-2-yl) -p-cresol, 2- (2H-benzotriazole-2-yl)- 4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazole-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H) -benzotriazole-2 -Il] -4-methyl-6-t-butylphenol, 2- (2H-benzotriazole-2-yl) -4,6-di-t-butylphenol, 2- (2H-benzotriazole-2-yl)- 4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazole-2-yl) -4-methyl-6- (3,4,5,6-tetrahydrophthalimidylmethyl) ) Phenol, methyl 3- (3- (2H-benzotriazole-2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product, 2- (2H-benzotriazole-2) -Il) -6- (straight 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-benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy-C7-9 side chain and linear alkyl Esther can be mentioned.

Examples of benzotriazine compounds include 2-mono (hydroxyphenyl) -1,3,5-triazine compound, 2,4-bis (hydroxyphenyl) -1,3,5-triazine compound, and 2,4,6-tris. Examples thereof include (hydroxyphenyl) -1,3,5-triazine compounds, and specifically 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-triazine, 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, 2,4,6-tris (2-hydroxy-4-methoxyphenyl) -1,3, 5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-propoxyphenyl) -1, 3,5-triazine, 2,4,6-tris (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-butoxyphenyl)- 1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-octyl) Oxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4,6-tris ( 2-Hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyethoxyphenyl) -1,3,5-triazine, 2,4 6-Tris (2-Hydroxy-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-Tris (2-hydroxy-4-propoxyethoxyphenyl) -1,3,5-Triazine, 2,4,6-tris (2-hydroxy-4-methoxycarbonylpropyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxycarbonylethyloxyphenyl)- 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-methoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4) -Ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-propoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-Hydroxy-3-methyl-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-butoxyphenyl) -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-ethoxyethoxyphenyl)- 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-methoxycarbonylpropyloxy) Phenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl) -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 and the like can be mentioned.
Among them, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4] is highly compatible with amorphous thermoplastic resins, especially acrylic resins, and has excellent absorption characteristics. -(3-alkyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton ("alkyloxy" means long-chain alkyloxy groups such as octyloxy, nonyloxy, decyloxy) Examples thereof include UV absorbers having.

As the ultraviolet absorber, benzotriazole-based compounds and benzotriazine-based compounds are particularly preferable from the viewpoint of compatibility with the resin and volatilization during heating, and decomposition of the ultraviolet absorber itself is suppressed by heating during extrusion processing. From the viewpoint, benzotriazine compounds are preferable.

Only one kind of these ultraviolet absorbers may be used alone, or two or more kinds thereof may be used in combination.

Ultraviolet absorbers are usually added to absorb ultraviolet light and suppress transmission at 200 to 380 nm, but it is necessary to add a large amount for thin films and the like, and only one type of ultraviolet absorber is effective. Permeation cannot be suppressed. In the case of a thin film molded product, since absorption in the vicinity of 280 nm may not be suppressed by a kind of ultraviolet absorber, a compound having an absorption maximum at a wavelength of less than 315 nm and a compound having an absorption maximum at a wavelength of 315 nm or more. It is preferable to use in combination. Further, in order to efficiently suppress transmission with a small amount, it is preferable to use two kinds of a compound having an absorption maximum at a wavelength of 200 to 315 nm and a compound having an absorption maximum at a wavelength of 315 to 380 nm in combination.
For example, 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy] phenol (with an absorption maximum of 280-300 nm. ADEKA Co., Ltd., LA-46) or hydroxyphenyltriazine-based tinuvin 405 (manufactured by BASF) and 2,4-bis [2-hydroxy-4-butoxyphenyl]-having an absorption maximum of 350 to 380 nm. 6- (2,4-dibutoxyphenyl) 1,3,5-triazine (BASF, Tinubin 460), hydroxyphenyltriazine-based Tinubin 477 (BASF), 2,4,6-Tris (2-) It is preferable to use at least one selected from the group consisting of hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine (manufactured by ADEKA Co., Ltd., LA-F70).

The melting point (Tm) of the ultraviolet absorber is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 130 ° C. or higher, and further preferably 160 ° C. or higher. More preferred.
The weight loss rate of the ultraviolet absorber when the temperature is raised from 23 ° C. to 260 ° C. at a rate of 20 ° C./min is preferably 50% or less, more preferably 30% or less, and 15% or less. Is even more preferably, 10% or less is even more preferable, and 5% or less is even more preferable.

The blending amount of the ultraviolet absorber may be an amount that does not impair heat resistance, moist heat resistance, thermal stability, and molding processability and exhibits the effects of the present invention, but if a large amount is added, Since problems such as bleeding out may occur during processing, the amount is preferably 5 parts by mass or less (for example, 0.01 to 5 parts by mass) with respect to 100 parts by mass of the methacrylic resin, which is more preferable. Is 3 parts by mass or less, more preferably 2.5 parts by mass or less, still more preferably 2 parts by mass or less, and even more preferably 0.01 to 1.8 parts by mass.

Hereinafter, the characteristics of the methacrylic resin composition of the present embodiment will be described in detail.

<YI value (yellowness)>
The methacrylic resin composition of the present embodiment has a YI ₂₇₀ value of a test piece having a thickness of 2 mm, a width of 100 mm, and a length of 80 mm, which is produced by an injection molding machine under the conditions of a molding temperature of 270 ° C. and a mold temperature of 70 ° C. Is preferably 35 or less, more preferably 33 or less, still more preferably 30 or less, from the viewpoint of excellent thermal stability and suppression of coloring of the molded product.
Further, the methacrylic resin composition of the present embodiment was produced by an injection molding machine under the conditions of a molding temperature of 240 ° C. and a mold temperature of 70 ° C., and YI of a test piece having a thickness of 2 mm, a width of 100 mm and a length of 80 mm. _The value of ₂₄₀ is preferably 30 or less, more preferably 27 or less, still more preferably 25 or less, from the viewpoint of excellent thermal stability and suppression of coloring of the molded product.
The methacrylic resin composition of the present embodiment has excellent thermal stability, and the difference between the YI ₂₇₀ value and the YI ₂₄₀ value (YI _270- YI ₂₄₀ ) is large from the viewpoint that coloring is less likely to occur when molded at a high temperature. It is preferably 10 or less, and more preferably 5 or less.
The YI value can be measured by the method described in Examples described later.

<Heat resistance>
The glass transition temperature can be used as an index of heat resistance.
The glass transition temperature of the methacrylic resin composition of the present embodiment is preferably 115 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 121 ° C. or higher, still more preferably 121 ° C. or higher, from the viewpoint of heat resistance during actual use. Is 122 ° C. or higher, more preferably 123 ° C. or higher, still more preferably 124 ° C. or higher, and particularly preferably 125 ° C. or higher.
The glass transition temperature can be measured according to ASTM-D-3418, and specifically, it can be measured by the method described in Examples described later.

<Moldability>
As an index of moldability, for example, mold releasability can be used.
The releasability of the methacrylic resin and the methacrylic resin composition of the present embodiment is obtained when injection molding is performed at a molding temperature of 270 ° C. and a mold temperature of 85 ° C. to form a multipurpose molded piece A having a thickness of 4 mm according to ISO3167. It is preferable that the molded piece can be easily removed from the mold and no resin residue is generated in the mold even after repeated molding.
The releasability can be evaluated by the method described in Examples described later.

<Thermal stability>
When a film is produced using the methacrylic resin composition of the present embodiment, the resin may stay in a molten state in the molding machine. At that time, since the resin material stays at a high temperature for a long time, the resin material may not be easily thermally decomposed, that is, thermal stability may be required.
Further, when it is necessary to make the molded product of the present embodiment thin, it is necessary to perform molding at a high temperature, and high thermal stability may be required.
As an index of thermal stability, a weight loss rate when the weight is held at a predetermined temperature for a predetermined time and a temperature (thermal decomposition start temperature) when the weight is reduced by a predetermined rate can be used.

In the methacrylic resin composition of the present embodiment, specifically, in thermogravimetric analysis (TGA), the weight loss rate when held at about 290 ° C. for 30 minutes is preferably 5.0% or less. It is more preferably 4.0% or less, still more preferably 3.0% or less, and even more preferably 2.0% or less.
The thermal decomposition start temperature (temperature when the weight is reduced by 1%) (° C.) of the methacrylic resin composition of the present embodiment is preferably 290 ° C. or higher. It is more preferably 300 ° C. or higher, still more preferably 310 ° C. or higher, even more preferably 320 ° C. or higher, and even more preferably 325 ° C. or higher.
The thermal decomposition start temperature may be, for example, a 1% weight loss temperature (thermal decomposition start temperature), which is a temperature at which the weight is reduced by 1% when the temperature is raised.
The weight loss rate when the methacrylic resin and the resin composition are held at 290 ° C. for 30 minutes is defined as the weight loss rate (%) when the methacrylic resin and the resin composition are weighed under the following setting conditions and held at about 290 ° C. for 30 minutes. Can be calculated.
Measuring device: Differential type differential thermal balance Thermo plus EVO II TG8120 (manufactured by Rigaku Co., Ltd.)
Sample amount: Approximately 10 mg
Measurement atmosphere: Nitrogen (100 mL / min)
Measurement conditions: Hold at 50 ° C for 2 minutes, raise the temperature to 200 ° C at 20 ° C / min, raise the temperature to 250 ° C at 20 ° C / min, raise the temperature to the set temperature of 284 ° C at 10 ° C / min, and raise the temperature to 284 ° C. Hold at ° C for 60 minutes, and calculate the weight loss rate (%) after 30 minutes have passed from the start of holding. When the set temperature is 284 ° C, the measured temperature is about 290 ° C.
The temperature at the time of 1% weight reduction can be calculated as the temperature at which the weight of the resin and the resin composition is reduced by 1% under the following devices and conditions using the methacrylic resin and the resin composition.
Measuring device: Differential type differential thermal balance Thermo plus EVO II TG8120, manufactured by Rigaku Co., Ltd. Sample amount: Approximately 10 mg
Measurement atmosphere: Nitrogen (100 mL / min)
Measurement conditions: The temperature at which the weight was reduced by 1% while being held at 100 ° C. for 5 minutes and the temperature was raised to 400 ° C. at 10 ° C./min was defined as the thermal decomposition start temperature (1% weight loss temperature).

In the molding process of the molded product of the present embodiment, in order to prevent thermal decomposition and to have excellent thermal stability in practical use, the methacrylic resin contained in the molded product of the present embodiment has a main chain. It is effective to increase the proportion of the structural unit (B) having a ring structure and relatively reduce the amount of the methacrylic acid ester-based monomer unit (A) to be copolymerized. However, if the ratio of the (B) structural unit to the (A) monomer unit is too high, the characteristics such as molding fluidity and surface hardness required for the molded product may not be obtained. Therefore, it is preferable to determine the ratio of (A) monomer unit and (B) structural unit in consideration of the balance of these characteristics.
Further, increasing the copolymerization ratio of the structural unit (B) having a ring structure in the main chain is effective in suppressing the decomposition reaction due to depolymerization when exposed to a high temperature, and the structural unit (B) By increasing the ratio of (A) to the monomer unit, sufficient thermal stability can be imparted even if the amount of the thermal stabilizer is reduced. On the other hand, when the proportion of the methacrylic acid ester-based monomer unit (A) is relatively large, the amount of thermal decomposition in a high temperature environment increases. Here, a heat stabilizer may be added from the viewpoint of suppressing thermal decomposition, but if it is added in a large amount, the heat resistance may be lowered and problems such as bleed-out may occur during molding.

Then, as described above, a heat stabilizer may be included in the methacrylic resin composition in order to obtain the properties required for the molded product.

At this time, in the present embodiment, the content of the heat stabilizer is Y (content with respect to 100 parts by mass of methacrylic resin (parts by mass)), the content of methacrylic acid ester-based monomer unit (A) is P, and the main content is When the content of the structural unit (B) having a ring structure in the chain is Q (both refer to the content (mass%) with respect to 100% by mass of the methacrylic resin), thermal decomposition suppression at high temperature, From the viewpoint of the balance between moldability and heat resistance, the content Y (part by mass) is preferably 0.053 × P / Q −0.4 or more, and more preferably 0.053 × P / Q. It is −0.35 or more, more preferably 0.053 × P / Q −0.3 or more, still more preferably 0.053 × P / Q −0.27 or more, and even more preferably. Is 0.053 × P / Q-0.25 or more.

(Manufacturing method of methacrylic resin composition)
The methacrylic resin composition of the present embodiment melts the methacrylic resin of the present embodiment described above, a rubber polymer optionally added, other resins other than the methacrylic resin, and additives. It can be manufactured by kneading.

Examples of the method for producing the methacrylic resin composition include a method of kneading using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, and a Banbury mixer. Among them, kneading with an extruder is preferable in terms of productivity. The kneading temperature may be in accordance with the preferable processing temperature of the polymer constituting the methacrylic resin and other resins to be mixed, and as a guide, it is in the range of 140 to 300 ° C., preferably in the range of 180 to 280 ° C. Further, it is preferable that the extruder is provided with a vent port for the purpose of reducing the volatile content.

(Molded body)
Examples of the molded body of the present embodiment include transparent conductive substrates such as display front plates, optical lenses, light guide plates, meter panels, in-vehicle center consoles, and touch panels, optical communication systems, optical exchange systems, and optical measurement system fields. , A polarizing plate protective film used for displays such as waveguides, lens arrays, optical fibers, liquid crystal displays, plasma displays, and organic EL displays; retardation plates such as 1/4 wave plates and 1/2 wave plates. ..
The molded product of the present embodiment is characterized by containing the methacrylic resin composition of the present embodiment described above.

When the molded product of the present embodiment is an optical material having a portion through which light passes, the maximum length of the path through which light passes in the molded product is preferably 100 μm to 1100 mm, more preferably 200 μm to 210 mm.
Specifically, in the case of a display front plate, the thickness is preferably 200 μm to 10 mm, in the case of a meter panel, it is preferably 200 μm to 10 mm, and in the case of a film, it is 5 to 200 μm. In the case of a light guide plate, the diagonal length is preferably 20 to 210 mm.

Hereinafter, the characteristics of the molded product of the present embodiment will be described.

<In-plane phase difference Re>
The molded product of the present embodiment has an absolute value of in-plane retardation Re (for example, an absolute value of in-plane retardation Re measured using a test piece molded at a molding temperature of 240 ° C. and / or 270 ° C.). , 30 nm or less, more preferably 20 nm or less, still more preferably 15 nm or less, still more preferably 11 nm or less, still more preferably 10 nm or less, still more preferably 5 nm or less, and particularly preferably 4 nm or less. However, here, the in-plane direction phase difference Re is a value obtained by converting to a thickness of 100 μm.
In general, the absolute value of the in-plane directional phase difference Re is an index indicating the magnitude of birefringence. The molded product of the present embodiment is sufficiently small with respect to the birefringence of existing resins (for example, PMMA, PC, triacetyl cellulose resin, cyclic olefin resin, etc.), and low birefringence or zero birefringence is required as an optical material. Suitable for various applications.
On the other hand, when the absolute value of the in-plane directional phase difference Re exceeds 30 nm, it means that the refractive index anisotropy is high, and it cannot be used for applications requiring low birefringence or zero birefringence as an optical material. is there. In addition, stretching may be performed to improve the mechanical strength of the optical material (for example, film, sheet, etc.), but if the absolute value of the in-plane directional phase difference Re after stretching exceeds 30 nm, It does not mean that a low birefringence or zero birefringence material has been obtained as an optical material.
Further, in the molded product of the present embodiment, the absolute value (Re ₂₄₀ value) of the in-plane direction phase difference Re of the test piece molded at the molding temperature 240 ° C. and the in-plane direction position of the test piece molded at the molding temperature 270 ° C. The difference (Re _240- Re ₂₇₀ ) from the absolute value (Re ₂₇₀ value) of the phase difference Re is preferably 10 nm or less, more preferably 4 nm or less, and particularly preferably 2 nm or less.
In the molded product of the present embodiment, the side chain (R ¹² in the formula (I)) has 6 to 20 carbon atoms (preferably 6 to 18, more preferably 10 to 18) (however, benzyl group and phenyl group are excluded. ) (C) The monomer forming the monomer unit is not only excellent in color tone but also has a small birefringence, so that the contribution to the birefringence is small. In addition, since the resin fluidity is increased, orientation is less likely to be applied, and the phase difference is reduced during molding at a low temperature, which is effective for improving color tone. Therefore, since Re ₂₄₀ becomes small, the difference between the Re ₂₄₀ value and the Re ₂₇₀ value (Re _240- Re ₂₇₀ ) tends to be small, and it is easy to obtain a molded product suitable for an optical material having low birefringence.
The in-plane phase difference Re value can be measured by the method described in Examples described later.

<Thickness direction phase difference Rth>
In the molded product of the present embodiment, the absolute value of the phase difference Rth in the thickness direction is preferably 30 nm or less. However, here, the phase difference Rth in the thickness direction is a value obtained by converting to a thickness of 100 μm.
The absolute value of the thickness direction retardation Rth is more preferably 20 nm or less, further preferably 15 nm or less, and particularly preferably 11 nm or less.
This thickness direction retardation Rth is an index that correlates with the viewing angle characteristics of the display device incorporating the optical film when the optical material, particularly the optical film, is used. Specifically, the smaller the absolute value of the thickness direction phase difference Rth, the better the viewing angle characteristic, and the smaller the change in color tone of the display color and the decrease in contrast depending on the viewing angle.
The molded product of the present embodiment is characterized in that the absolute value of the phase difference Rth in the thickness direction is very small as compared with existing resins (for example, PMMA, PC, triacetyl cellulose resin, cyclic olefin resin, etc.).
The thickness direction phase difference Rth can be obtained by the following method.
For the methacrylic resin or the methacrylic resin composition, the phase difference (nm) at a wavelength of 589 nm was measured using a phase difference measuring device (KOBRA-21ADH) manufactured by Oji Measuring Instruments Co., Ltd., and the obtained value was used as the thickness. It is converted into a molded body of 100 μm and used as a measured value.
The absolute value of birefringence (| Δn |) and the thickness direction phase difference (Rth) have the following relationship.
Rth = | Δn | × d
(D: Sample thickness)
The absolute value of birefringence (| Δn |) is the value shown below.
| Δn | = | (nx + ny) /2-nz |
(Nx: refractive index in the stretching direction, ny: refractive index in the in-plane direction perpendicular to the stretching direction, nz: refractive index in the thickness direction out of the plane and perpendicular to the stretching direction)
Here, in an ideal film that is completely optically isotropic in all three-dimensional directions, both the in-plane phase difference (Re) and the thickness direction phase difference (Rth) are zero.

<Photoelastic modulus>
Molded body of the present embodiment, the absolute value of the photoelastic coefficient _{C R} is preferably at 3.0 × ¹⁰ -12 ^{Pa -1} or less, be 2.0 × at ¹⁰ -12 ^{Pa -1} or less More preferably, it is 1.0 × ^10-12 Pa ^-1 or less.
The photoelastic modulus is described in various documents (see, for example, Review Articles of Chemistry, No. 39, 1998 (published by the Society Publishing Center)) and is defined by the following formulas (ia) and (ib). Is. As the value of photoelastic coefficient C _R is close to zero, it can be seen that change in birefringence due to an external force is small.
_{C R = | Δn | / σ} R ··· (i-a)
| Δn | = nx-ny ... (i-b)
(In the equation, _CR is the photoelastic coefficient, σ _R is the elongation stress, | Δn | is the absolute value of birefringence, nx is the refractive index in the extension direction, and ny is perpendicular to the extension direction in the plane. The refractive index in each direction is shown.)
Photoelastic coefficient C _R of the shaped body of the present embodiment, the existing resin (e.g., PMMA, PC, triacetyl cellulose resins, cyclic olefin resins, etc.) is sufficiently small compared to. Therefore, since the (photoelastic) birefringence caused by the external force is not generated, the birefringence is less likely to be changed. Further, since birefringence (photoelasticity) due to residual stress during molding is unlikely to occur, the birefringence distribution in the molding body is also small.
The photoelastic modulus can be obtained by the following method.
The photoelastic coefficient (Pa ^-1 ) can be measured for a methacrylic resin or a methacrylic resin composition using a birefringence measuring device described in detail in Polymer Engineering and Science 1999, 39, 2349-2357.
Specifically, a film tensioning device (manufactured by Imoto Seisakusho) is placed in the path of the laser beam, and birefringence of the film is performed using RETS-100 manufactured by Otsuka Electronics Co., Ltd. while applying tensile stress at 23 ° C. , Measure in the wavelength range of 400 to 800 nm by the rotary photon method. The strain rate during stretching is 50% / min (chuck spacing: 50 mm, chuck moving speed: 5 mm / min), and the test piece width is 6 mm.
From the relationship between the absolute value of birefringence (| Δn |) and the elongation stress (σR), the slope of the straight line is obtained by least squares approximation, and the photoelastic coefficient (CR) is calculated according to the following equation. In the calculation, data with an elongation stress of 2.5 MPa ≦ σR ≦ 10 MPa is used.
CR = | Δn | / σR
Here, the absolute value of birefringence (| Δn |) is the value shown below.
| Δn | = | nx-ny |
(Nx: refractive index in the stretching direction, ny: refractive index in the direction perpendicular to the stretching direction in the plane)

Hereinafter, the relationship between the birefringence Δn and the draw ratio S will be described.
When the molded product of the present embodiment is a film, the film has a least squares approximate linear relational expression (ii-a) between the birefringence Δn (S) and the draw ratio S when the characteristics are evaluated as a uniaxially stretched film. , It is preferable that the value of the slope K satisfies the following formula (ii-b).
Δn (S) = K × S + C ... (ii-a)
| K | ≤ 0.30 x ^10-5 ... (ii-b)
(In the formula, Δn (S) indicates birefringence, S indicates the stretching ratio, and here, birefringence Δn (S) is a value measured as a film (value obtained by the above formula (ib)). Is a value obtained by converting to 100 μm thickness, C is a constant, and indicates birefringence when unstretched.)
The absolute value of the slope K (| K |) is more preferably 0.15 × 10 ^-5 or less, and further preferably 0.10 × 10 ^-5 or less.
Here, the value of K is a value when the glass transition temperature (Tg) is measured by DSC measurement of the film and uniaxial stretching is performed at a stretching temperature of (Tg + 20) ° C. and a stretching speed of 500 mm / min. ..
It is generally known that the amount of increase in birefringence decreases as the stretching rate is reduced. As the value of K, for example, the value of birefringence (Δn (S)) expressed by the uniaxially stretched film obtained by stretching the stretch ratio (S) to 100%, 200%, and 300% is measured. Then, these values can be calculated by plotting them against the stretching ratio and approximating the least squares method. Further, the stretching ratio (S) is a value represented by the following equation, where L _{0 is} the distance between chucks before stretching and L ₁ is the distance between chucks after stretching.
S = {(L _1- L ₀ ) / L ₀ } x 100 (%)
A film-shaped or sheet-shaped molded product may be stretched for the purpose of increasing mechanical strength. In the above relational expression, the value of the slope K represents the magnitude of the change in the birefringence (Δn (S)) with respect to the stretching ratio (S), and the larger K is, the larger the amount of change in the birefringence with respect to stretching is. The smaller the value, the smaller the amount of change in birefringence with respect to stretching.
In the film according to the present embodiment, the value of the inclination K is sufficiently smaller than that of existing resins (for example, PMMA, PC, triacetyl cellulose resin, cyclic olefin resin, etc.). Therefore, the existing resin has a feature that the birefringence increases due to the stretching orientation during the stretching process, whereas the birefringence does not easily increase even after the stretching process.

<Refractive index>
The refractive index d _blend of the molded product of the present embodiment is preferably in the range of 1.48 to 1.53. In particular, when the obtained molded product is used as an optical film, its refractive index d _blend is more preferably in the range of 1.48 to 1.51. If the refractive index d _blend is within this range, it can be suitably used as a polarizing plate material used in a liquid crystal television. The refractive index of the conventional polarizing plate material is, for example, the refractive index of the polyvinyl alcohol resin is 1.49 to 1.53, the refractive index of the triacetyl cellulose resin is 1.49, and the refractive index of the cyclic polyolefin resin is 1. 53.

<Transparency>
The total light transmittance can be used as an index of transparency.
The total light transmittance of the molded body of the present embodiment may be appropriately optimized according to the application, but when used in an application requiring transparency, the total light transmittance at a thickness of 100 μm is considered from the viewpoint of visibility. The rate is preferably 80% or more. It is more preferably 85% or more, further preferably 88% or more, and particularly preferably 90% or more.
It is preferable that the total light transmittance is high, but practically, even if it is 94% or less, sufficient visibility can be ensured.
The total light transmittance, the light transmittance of 380 nm and the light transmittance of 280 nm, which will be described later, can be obtained by the following methods.
Using a film (about 100 μm thick) made of a methacrylic resin or a methacrylic resin composition, the total light transmittance is measured in accordance with the ISO13468-1 standard and used as an index of transparency.

The molded product of this embodiment is expected to be used outdoors or in a liquid crystal television, and may be exposed to ultraviolet rays depending on the application. At this time, the transparency may be lowered due to yellowing due to ultraviolet rays, and a method of adding an ultraviolet absorber to the molded product to suppress it may be used.
In that case, the light transmittance at 380 nm at a thickness of 100 μm is preferably 15% or less, more preferably 10% or less, still more preferably 8% or less.
Similarly, the light transmittance at 280 nm at a thickness of 100 μm is preferably 15% or less, more preferably 10% or less, still more preferably 8% or less.

<Appearance>
The molded product of the present embodiment is preferably excellent in appearance.
For the appearance, for example, the number of bubbles having a major axis of 100 μm or more contained in 100 cm ² of the film when the film is formed at a set temperature of 290 ° C. and a thickness of about 100 μm is calculated using an optical microscope, and the number thereof is calculated. Can be evaluated at.
In this case, the number of bubbles per 100 cm ^{2 of} the film surface is preferably less than 5, more preferably less than 3, and even more preferably less than 2.

(Manufacturing method of molded product)
The molded product of the present embodiment can be produced by molding using the methacrylic resin composition of the present embodiment described above.

As a method for producing the molded body, known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, cast molding and the like can be applied. , Secondary processing molding methods such as pressure molding and vacuum molding can also be used.
Further, a methacrylic resin (composition) is kneaded and manufactured using a kneader such as a heating roll, a kneader, a Banbury mixer, or an extruder, then cooled and pulverized, and further molded by transfer molding, injection molding, compression molding, or the like. Can also be mentioned as an example of a method for producing a molded product.

When the molded product is a film, the molded film may be stretched by a known method.
The film may be vertically uniaxially stretched in the mechanical flow direction (MD direction), horizontally uniaxially stretched in the direction orthogonal to the mechanical flow direction (TD direction), or sequentially biaxially stretched by roll stretching and tenter stretching. , Simultaneous biaxial stretching by tenter stretching, biaxial stretching by tubular stretching, inflation stretching, biaxial stretching by tenter method sequential biaxial stretching and the like. The strength of the film can be improved by stretching.
In particular, describing the tenter method sequential biaxial stretching, in such a method, for example, a raw material resin is supplied to a single-screw or twin-screw extruder, melt-kneaded, and then a sheet extruded from a T-die is placed on a cast roll. Lead to and solidify. Subsequently, the extruded sheet is introduced into a roll-type longitudinal stretching machine and stretched in the mechanical flow direction (MD direction), and then the longitudinally stretched sheet is introduced into a tenter-type transverse stretching machine to be orthogonal to the mechanical flow direction. Stretch in the direction (TD direction). According to this tenter method sequential biaxial stretching, the stretching ratio can be easily controlled, and a film having a well-balanced orientation in the MD direction and the TD direction can be obtained.

The final draw ratio can be determined from the heat shrinkage rate of the obtained molded / stretched body. The draw ratio is preferably 0.1 to 400%, more preferably 10 to 400%, and even more preferably 50 to 350% in at least one direction. If it is less than the lower limit, the folding resistance tends to be insufficient, and if it exceeds the upper limit, breakage or tearing occurs frequently in the film manufacturing process, and the film tends to be continuously and stably manufactured. By designing in this range, a stretched molded product preferable from the viewpoints of birefringence, heat resistance and strength can be obtained.

The stretching temperature is preferably Tg-30 ° C to Tg + 50 ° C. Here, Tg (glass transition point) refers to a methacrylic resin composition constituting a film. In order to obtain good surface properties in the obtained film, the lower limit of the stretching temperature is preferably (Tg-20 ° C.) or higher, more preferably (Tg-10 ° C.) or higher, still more preferably Tg or higher, especially. It is preferably (Tg + 5 ° C.) or higher, and particularly preferably (Tg + 7 ° C.) or higher. The upper limit of the stretching temperature is preferably Tg + 45 ° C. or lower, more preferably (Tg + 40 ° C.) or lower.

When the molded product of the present embodiment is used as an optical film, it is preferable to perform heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropic property and mechanical properties. The heat treatment conditions may be appropriately selected in the same manner as the heat treatment conditions performed on the conventionally known stretched film, and are not particularly limited.

Here, when the molded product of the present embodiment is used as an optical film, the target film and the film and the non-adhesive resin are co-extruded with a multilayer die, and then the non-adhesive resin layer is formed. A method of removing and obtaining only the target film can be preferably used.
This method is preferable from the viewpoints (a) to (c) below.
(A) The film-forming stability can be improved by the heat insulating effect of the non-adhesive resin layer and the effect of improving the film strength.
(B) The effect of preventing dust, suspended matter, dust, vaporized substances such as additives, and other foreign substances in the air from adhering to the film during film formation.
(C) The effect of preventing scratches on the film surface during handling after film formation and preventing the adhesion of foreign substances such as dust.
Even if the non-adhesive resin is applied to only one side of the methacrylic thermoplastic resin and co-extruded, the effects (a) to (c) above can be obtained, but both sides of the methacrylic thermoplastic resin are non-adhesive. A higher effect can be obtained by sandwiching it with the resin of the above and co-extruding it.
If the solubility parameter value of the non-adhesive resin co-extruded with the multilayer die is close to the solubility parameter value of the resin constituting the film, the compatibility between the two resins becomes good and they are mixed when blended. It tends to be easy, and the resin layers that come into contact with each other when co-extruded during film formation tend to adhere to each other. Therefore, when selecting a non-adhesive resin, it is preferable to select a resin having a polarity different from that of the resin constituting the film and having a large difference in the solubility parameter value.
Further, at the time of co-extrusion, if the temperatures and viscosities of the two contacting resins are significantly different, the layers tend to be disturbed at the interface of the contacting resins, and a film having good transparency tends to be obtained. Therefore, when selecting a resin that is non-adhesive to the methacrylic thermoplastic resin that is the main component of the film, the temperature of the methacrylic thermoplastic resin is close to the temperature of the methacrylic thermoplastic resin in the die. It is preferable to select a resin having a viscosity close to that of the viscosity.
As the non-adhesive resin, a wide variety of thermoplastic resins can be used as long as the above conditions are satisfied, and preferred examples thereof include polyolefin-based resins, styrene-based resins, nylon-based resins, and fluorine-containing resins. A polyolefin-based resin is preferable, and a polypropylene-based resin is particularly preferable.

The methacrylic resin of the present embodiment and the methacrylic resin composition of the present embodiment can be suitably used as materials for various molded bodies (various members) such as films.
Applications of the molded body include, for example, household goods, OA equipment, AV equipment, battery electrical equipment, lighting equipment, tail lamps, meter covers, head lamps, light guide rods, lenses, meter panels, center consoles and other automobile parts. Light guide plate, diffuser plate, polarizing plate protective film, 1/4 wavelength used for housing applications, sanitary applications such as sanitary ware substitutes, and displays such as liquid crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions. Plates, 1/2 wavelength plates, viewing angle control films, retardation films such as liquid crystal optical compensation films, display front plates, display substrates, lenses, touch panels, etc., and suitable for transparent substrates used in solar cells, etc. Can be used for. In addition, in the fields of optical communication systems, optical exchange systems, and optical measurement systems, it can also be used for waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. It can also be used as a modifier for other resins.

The molded product using the methacrylic resin of the present embodiment and the resin composition thereof can be further subjected to surface functionalization treatments such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

Hereinafter, specific examples and comparative examples will be described, but the present invention is not limited thereto.

[material]
The raw materials used in Examples and Comparative Examples described later are shown below.
[[Monomers constituting methacrylic resin]]
-Methyl methacrylate (MMA): manufactured by Asahi Kasei Chemicals Co., Ltd. (2,4-dimethyl-6-t-butylphenol (2,4-di-methyl-6-tert) manufactured by Chugai Trading Co., Ltd. as a polymerization inhibitor -Butylpeneol) with 2.5 ppm added)
・ N-Phenyl maleimide (N-PMI): manufactured by Nippon Catalyst Co., Ltd. ・ N-cyclohexyl maleimide (N-CMI): manufactured by Nippon Catalyst Co., Ltd. ・ n-hexyl acrylate (HA): manufactured by Tokyo Kasei Kogyo Co., Ltd. ・ n- Dodecyl Acrylate (DDA): Made by Osaka Organic Chemical Industry Co., Ltd. Ethyl Acrylate (EA): Made by Mitsubishi Gas Chemical Company, Inc. n-Butyl Acrylate (BA): Made by Mitsubishi Gas Chemical Company, Ltd.

[[Organic solvent]]
・ Metaxylene: manufactured by Mitsubishi Gas Chemical Company, Ltd. ・ Toluene: manufactured by Wako Pure Chemical Industries, Ltd.

[[Other]]
-N-octylmercaptan (NOM): Manufactured by Kao Corporation, used as a chain transfer agent.
-T-dodecyl mercaptan: Made by Wako Pure Chemical Industries, Ltd., used as a chain transfer agent.
-Dimethyl phosphite: manufactured by Wako Pure Chemical Industries, Ltd.
-Perhexa C-75 (EB): manufactured by NOF CORPORATION, with a purity of 75% (containing 25% ethylbenzene), used as a polymerization initiator.
-T-Butylperoxyisopropyl carbonate: manufactured by NOF CORPORATION, used as a polymerization initiator.
-Perhexa 25B: Made by NOF Corporation, with a purity of 90% or more, used as a polymerization initiator.

[[Additive]]
(A-1) ADEKA STAB PEP-36: Made by ADEKA Corporation (a-2) ADEKA STAB 1178: Made by ADEKA Corporation (a-3) Irganox 1010: Made by BASF

Hereinafter, a method for measuring the characteristics of the methacrylic resin and the methacrylic resin composition will be described.

(I. Measurement of weight average molecular weight of methacrylic resin and methacrylic resin composition)
The weight average molecular weight (Mw) of the methacrylic resin and the methacrylic resin composition produced in the production examples described later was measured with the following equipment and conditions.
-Measuring device: Gel Permeation Chromatography (HLC-8320GPC) manufactured by Tosoh Corporation
·Measurement condition:
Column: One TSKguardcolum SuperH-H, two TSKgel SuperHM-M, and one TSKgel SuperH2500 were connected in series and used. In this column, the high molecular weight elutes quickly and the low molecular weight elutes late.
The developing solvent: tetrahydrofuran, the flow rate; 0.6 mL / min, and 0.1 g / L of 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard.
Detector: RI (differential refractometer) detector Detection sensitivity: 3.0 mV / min Column temperature: 40 ° C
Sample: 0.02 g solution of methacrylic resin or methacrylic resin composition in tetrahydrofuran 20 mL Injection amount: 10 μL
Standard sample for calibration curve: Weight peak of monodispersity The following 10 types of methyl methacrylate (PMMA Calibration Kit M-M-10, manufactured by Polymer Laboratories, manufactured by Polymer Laboratories) having known molecular weights and different molecular weights were used.
Weight peak molecular weight (Mp)
Standard sample 1 1,916,000
Standard sample 2 625,500
Standard sample 3 298,900
Standard sample 4 138,600
Standard sample 5 60, 150
Standard sample 6 27,600
Standard sample 7 10,290
Standard sample 8 5,000
Standard sample 9 2,810
Standard sample 10 850
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin or the methacrylic resin composition was measured.
The weight average molecular weight (Mw) of the methacrylic resin or the methacrylic resin composition was determined based on the area area on the GPC elution curve and the calibration curve of the cubic approximation formula.

(II. Measurement of composition of monomer unit)
For the methacrylic resin obtained by polymerization, NMR and FT-IR measurements were carried out to confirm the composition of the monomer unit and the structural unit.
NMR: JNM-ECA500 manufactured by JEOL Ltd.
FT-IR: manufactured by JASCO Corporation, IR-410, ATR method (Dura Scope (ATR crystal: diamond / ZnSe), resolution: 4 cm ^-1 ) was used.

(III. Measurement of the total amount of specific components)
Octadecyl 3- (3,5-di-tert-butyl-4-) for the methacrylic resin and the methacrylic resin composition (specifically, the reprecipitated soluble component) prepared in the production examples described below according to the following devices and conditions. The total amount (% by mass) of the components including the dimer and trimer of the monomer was calculated by performing GC / MS measurement using hydroxyphenyl) propionate as an internal standard substance.

First, a standard solution was prepared according to the following procedure. 25.0 mg of octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate was collected in a 100 mL volumetric flask. Chloroform was added to the full marked line of this volumetric flask to prepare a 0.025 mass% octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate standard solution.
Then, a solution for GC / MS measurement was prepared according to the following procedure. About 0.5 g of the sample was dissolved in 10 mL of chloroform and reprecipitated from 60 mL of methanol. The insoluble matter was filtered off, and the chloroform / methanol soluble component was heated at 60 ° C. for 90 minutes under a nitrogen blow to dry. 1 mL of the above standard solution was added to the concentrated soluble component and dissolved to prepare a solution for GC / MS measurement.
Then, GC / MS measurement was carried out using 1 μL of the above GC / MS measurement solution under the following equipment and conditions.
Under the following equipment and conditions, it was confirmed in advance by another GC / MS measurement that the dimer and trimer peaks of the monomer used were observed during the retention time from 22 minutes to 32 minutes. Then, based on this, the total area value of the peaks observed during the holding time of 22 minutes to 32 minutes in the GC / MS measurement of the above GC / MS measurement solution is set to the monomer dimer and trimer. It was assumed that it was derived from a component including the body and the like. In this way, the total amount of the components contained in the above-mentioned GC / MS measurement solution was calculated.
In addition, the embodiment is a methacrylic resin composition containing an additive or the like in addition to the methacrylic resin, and a peak derived from an additive or the like such as a heat stabilizer appears in the above retention time range in GC / MS measurement. In this case, the area value of the peak derived from the additive or the like was subtracted from the total area value to calculate the total amount of the components. If the peak could not be attributed, it was included in the total amount as an unknown component.

-Measuring device Made by Agilent, GC / MS GC-7890A, MSD-5975C
-Measurement conditions Column: HP-5MS (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Carrier gas: helium (1 mL / min)
Detector: MSD
Ionization method: EI
Oven temperature: 50 ° C (hold for 5 minutes) ~ (heat up at 10 ° C / min) to 325 ° C (hold for 10 minutes)
Injection port temperature: 325 ° C
Transfer temperature: 325 ° C
Mass spectrum range: 20-800
Split ratio: 10: 1
Injection volume: 1 μL
Internal standard: Octadecil 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate

The data in the above GC / MS measurement was processed according to the following procedure.
After calculating the peak area value of the detected octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, it is compared with the total peak area value detected in the component detection region in the sample. , The total amount of ingredients [mg] was estimated. The calculation formula is shown below.
(Total amount of components [mg]) = (Addition amount of octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate 0.25 [mg]) × (total peak area value of components) / Octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate peak area value)
The total content (% by mass) of the components was calculated by dividing the total amount of the components by the amount of the sample after the reprecipitation treatment.
In the GC / MS total ion chromatogram, the baseline may gradually increase as the oven temperature increases. For the part where the slope of the baseline becomes large, in order to calculate the accurate peak area value, the integration is performed in several times in consideration of the slope of the baseline, and these integrated values are added up. It was set as "the peak total area value of the components".

(IV. Percentage of components in a specific molecular weight range)
Using the molecular weight measuring device of (I) described above, the content of the component having a weight average molecular weight of 10,000 or less was determined from the fractionation of the components having a molecular weight of 500 or more and 10,000 or less.

Hereinafter, a method for evaluating the characteristics of the methacrylic resin, the methacrylic resin composition, and the molded product will be described.

<1. Heat resistance: Glass transition temperature>
The methacrylic resin or the methacrylic resin composition obtained in Examples and Comparative Examples described later was measured in accordance with ASTM-D-3418 using a thermal analyzer (Diamond DSC manufactured by PerkinElmer). , The glass transition temperature (° C) was calculated by the midpoint method. The evaluation results are shown in Table 1.

<2-a. Moldability: Melt flow rate (MFR)>
Based on JIS K7210, the measurement was performed at a test temperature of 260 ° C. and a load of 2.16 kg.

<2-b. Moldability: Mold release>
An ISO dumbbell test piece A was molded at a molding temperature of 270 ° C. and a mold temperature of 85 ° C. using an injection molding machine (EX-100SX, manufactured by Toshiba Machine Co., Ltd.). The mold releasability of the test piece from the mold was judged from the ease of removal from the mold and the appearance of the molded piece. The molding was carried out by drying the pellets and having a water content of 0.06% by mass or less.
Then, the releasability was evaluated according to the following criteria.
Good (○): The molded piece is easily removed from the mold, and no resin residue is generated on the mold even after repeated molding. In addition, the smoothness of the surface of the obtained molded piece is also excellent and has an aesthetic appearance.
Normal (Δ): The resin does not easily come off from the mold, and when molding is repeated, resin residue is generated on the mold. When resin residue begins to be generated, a molded piece having deteriorated surface smoothness is given.
Bad (x): The resin does not come off from the mold. Even if it comes off, resin adhesion remains on the mold. Further, the surface of the obtained molded piece is poor in smoothness and a pattern remains.

<3. Thermal stability evaluation: YI value>
The methacrylic resin and the methacrylic resin composition obtained in Examples and Comparative Examples described later are subjected to a molding temperature of 270 ° C. and a mold temperature of 70 ° C. by an injection molding machine (manufactured by Toshiba Machine Co., Ltd., EC-100SX). A test piece having a thickness of 2 mm, a width of 100 mm, and a length of 100 mm was prepared.
Until the injection molding conditions became stable, 20 shots were discarded and the samples after the 21st shot were used. In molding, pellets of a methacrylic resin or a methacrylic resin composition were dried and carried out at a water content of 0.06% by mass or less.
The obtained molded piece is cut to 80 mm in the longitudinal direction, and the length of the molded piece is lengthened at a cutter rotation speed of 8500 rpm and a feed rate of 1 m / min using a polishing machine (Plastic Beauty manufactured by Megalotechnica Co., Ltd.). Polished both end faces perpendicular to the direction.
Using a color difference meter (manufactured by Nippon Denshoku Co., Ltd., 300A), place the polished molded piece so that the polished end face is perpendicular to the light source, and place YI ₂₇₀ (optical path length 80 mm). It was measured.
Further, a molded piece was prepared under the same conditions as YI ₂₇₀ except that the molding temperature was set to 240 ° C., and YI ₂₄₀ was measured.

Hereinafter, production examples of the methacrylic resin and the methacrylic resin composition will be described.
The charged amount (parts by mass) of each component in the table is represented by the amount when the total added amount of the charged components is 100 parts by mass.

<4. Optical characterization: Re value>
The methacrylic resin and the methacrylic resin composition obtained in Examples and Comparative Examples described later are subjected to a molding temperature of 270 ° C. and a mold temperature of 70 ° C. by an injection molding machine (EC-100SX, manufactured by Toshiba Machine Co., Ltd.). A test piece having a thickness of 2 mm, a width of 100 mm, and a length of 100 mm was prepared.
Until the injection molding conditions became stable, 20 shots were discarded and the samples after the 21st shot were used. In the molding, pellets of the methacrylic resin or the methacrylic resin composition were dried and carried out at a water content of 0.06% by mass or less.
The phase difference Re ₂₇₀ (nm) at a wavelength of 589 nm was measured using a phase difference measuring device (KOBRA-21ADH) manufactured by Oji Measuring Instruments Co., Ltd.
Further, a molded piece was prepared under the same conditions as Re ₂₇₀ except that the molding temperature was set to 240 ° C., and Re ₂₄₀ was measured.

[Example 1]
468 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), in a 1.25 m ³ reaction kettle equipped with a stirrer equipped with paddle blades, a temperature sensor, a cooling tube, and a nitrogen introduction tube. 78 kg of N-cyclohexylmaleimide (CMI), 12 kg of n-dodecylacrylate (DDA), 400.0 kg of metaxylene, and 0.45 kg of n-octyl mercaptan were charged and dissolved to prepare a raw material solution. The temperature was raised to 125 ° C. with stirring while passing nitrogen through it.
Separately, an initiator feed solution prepared by mixing 0.25 kg of perhexa C-75 and 1.80 kg of metaxylene was prepared.
When the raw material solution reached 127 ° C., the feed (addition) of the initiator feed solution (polymerization initiator mixed solution) was started with the profiles (1) to (6).
(1) 0.0 to 0.5 hours: Feed rate 1.00 kg / hour (2) 0.5 to 1.0 hours: Feed rate 0.50 kg / hour (3) 1.0 to 2.0 hours: Feed rate 0.42 kg / hour (4) 2.0 to 3.0 hours: Feed rate 0.35 kg / hour (5) 3.0 to 4.0 hours: Feed rate 0.14 kg / hour (6) 4. 0-7.0 hours: Feed rate 0.13 kg / hour After feeding the initiator over a total of 7 hours (B time = 7 hours), the reaction was continued for another 1 hour, and 8 hours from the start of addition of the initiator. The polymerization reaction was carried out until later.
During the polymerization reaction, the internal temperature was controlled at 127 ± 2 ° C. When the polymerization conversion rate of the obtained polymerization solution was measured, it was MMA: 93.7%, PMI: 95.5%, CMI: 91.2%, DDA: 84.0%. As a whole, the polymerization conversion rate was 95.0%.
The polymer solution obtained above was subjected to a volatilization treatment at 140 rpm and 10 kg / hour in terms of resin amount using a φ42 mm devolatilization extruder with 4 fore vents and 1 back vent to obtain resin pellets.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 127 ° C.
The composition determined by NMR was MMA unit: 77.5% by mass, PMI unit: 7.6% by mass, CMI unit: 13.6% by mass, and DDA unit: 1.3% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 2]
Polymerization was carried out in the same manner as in Example 1, to 100 parts by mass of the obtained polymerization solution, 1010: 0.05 parts by mass of Irganox and 1178: 0.05 parts by mass of Adecastab were added, and the mixture was stirred for 30 minutes and then removed. Pellets of a methacrylic resin composition were obtained in the same manner as in Example 1 except that the degassing treatment was performed using an air extruder.
The weight average molecular weight of the obtained pellets was 150,000, and the glass transition temperature was 128 ° C.
The composition determined by NMR was MMA unit: 77.6% by mass, PMI unit: 7.7% by mass, CMI unit: 13.4% by mass, and DDA unit: 1.3% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 3]
468 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), in a 1.25 m ³ reaction kettle equipped with a stirrer equipped with paddle blades, a temperature sensor, a cooling tube, and a nitrogen introduction tube. 78 kg of N-cyclohexylmaleimide (CMI), 12 kg of n-dodecylacrylate (DDA), 400.0 kg of metaxylene, and 0.45 kg of n-octyl mercaptan were charged and dissolved to prepare a raw material solution. The temperature was raised to 125 ° C. with stirring while passing nitrogen through it.
Separately, an initiator feed liquid A made by mixing 0.18 kg of perhexa 25B and 0.73 kg of metaxylene, and an initiator feed made by confusing 0.061 kg of perhexa 25B and 0.24 kg of metaxylene. Liquid B was prepared.
When the temperature of the raw material solution reached 130 ° C., the initiator feed solution A was fed for 10 minutes at a feed rate of 5.5 kg / hour. After 2 hours, the temperature of the raw material solution was lowered to 115 ° C. over 0.5 hours, and when the temperature reached 115 ° C., the initiator feed solution B was fed for 10 minutes at a feed rate of 1.8 kg / hour (B time). (= 2.83 hours), the reaction was continued as it was, and the polymerization reaction was carried out for a total of 13 hours to complete the reaction.
The obtained polymer solution was subjected to a volatilization treatment at 140 rpm and 10 kg / hour in terms of resin amount using a φ42 mm devolatilization extruder with 4 fore vents and 1 back vent to obtain resin pellets.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 128 ° C.
The composition determined by NMR was MMA unit: 76.6% by mass, PMI unit: 7.9% by mass, CMI unit: 13.9% by mass, and DDA unit: 1.6% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 4]
Polymerization was carried out in the same manner as in Example 1, and 0.10 part by mass of Adecaster PEP36: 0.10 part by mass was added to 100 parts by mass of the obtained polymerization solution, and the mixture was stirred for 30 minutes and then degassed using a degassing extruder. Pellets of the methacrylic resin composition were obtained in the same manner as in Example 1 except for the above.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 128 ° C.
The composition determined by NMR was MMA unit: 76.3% by mass, PMI unit: 8.0% by mass, CMI unit: 14.0% by mass, and DDA unit: 1.7% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 5]
450 kg of methyl methacrylate (MMA), 42 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 30 kg of n-dodecylacrylate (DDA), 400 kg of metaxylene, and 0.45 kg of n. -Polymerization was carried out in the same manner as in Example 3 except that octyl mercaptan was charged to obtain a polymerization solution.
Same as in Example 3 except that Adecaster PEP36: 0.10 part by mass was added to 100 parts by mass of the obtained polymerization solution, and the mixture was stirred for 30 minutes and then degassed using a degassing extruder. The pellets of the methacrylic resin composition were obtained.
The weight average molecular weight of the obtained pellets was 130,000, and the glass transition temperature was 120 ° C.
The composition determined by NMR was MMA unit: 74.7% by mass, PMI unit: 7.6% by mass, CMI unit: 13.2% by mass, and DDA unit: 4.5% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 6]
468 kg of methyl methacrylate (MMA), 42 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 12 kg of hexyl acrylate (HA), 400 kg of metaxylene, and 0.45 kg of n-octyl. Polymerization was carried out in the same manner as in Example 3 except that mercaptan was charged to obtain a polymerization solution.
Same as in Example 3 except that Adecaster PEP36: 0.10 part by mass was added to 100 parts by mass of the obtained polymerization solution, and the mixture was stirred for 30 minutes and then degassed using a degassing extruder. The pellets of the methacrylic resin composition were obtained.
The weight average molecular weight of the obtained pellets was 130,000, and the glass transition temperature was 125 ° C.
The composition determined by NMR was MMA unit: 77.7% by mass, PMI unit: 7.4% by mass, CMI unit: 13.2% by mass, and HA unit: 1.7% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Example 7]
In a 1.25 m ³ reaction vessel with a stirrer equipped with paddle blades, temperature sensor, cooling tube, nitrogen introduction tube, 429 kg of methyl methacrylate (MMA), 39 kg of N-phenylmaleimide (PMI), 71 kg. N-cyclohexylmaleimide (CMI), 11 kg of n-dodecylacrylate (DDA), 450 kg of metaxylene, and 0.41 kg of n-octyl mercaptan were charged and dissolved to prepare a raw material solution. The temperature was raised to 125 ° C. with stirring while passing nitrogen through it.
Separately, an initiator feed solution prepared by mixing 0.30 kg of perhexa C-75 and 1.82 kg of metaxylene was prepared.
When the raw material solution reached 127 ° C., the feed (addition) of the initiator feed solution (polymerization initiator mixed solution) was started with the profiles (1) to (3).
(1) 0.0 to 0.5 hours: Feed rate 0.51 kg / hour (2) 0.5 to 1.5 hours: Feed rate 0.26 kg / hour (3) 1.5 to 6.0 hours: Feed rate 0.36 kg / hour After the initiator was fed over a total of 6 hours (B time = 6 hours), the reaction was continued for another 2 hours, and the polymerization reaction was carried out from the start of addition of the initiator to 8 hours later. ..
During the polymerization reaction, the internal temperature was controlled at 127 ± 2 ° C. When the polymerization conversion rate of the obtained polymerization solution was measured, it was MMA: 95.9%, PMI: 96.8%, CMI: 93.1%, DDA: 84.2%. As a whole, the polymerization conversion rate was 95.4%.
The polymer solution obtained above was subjected to a volatilization treatment at 140 rpm and 10 kg / hour in terms of resin amount using a φ42 mm devolatilization extruder with 4 fore vents and 1 back vent to obtain resin pellets.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 127 ° C.
The composition determined by NMR was MMA unit: 77.3% by mass, PMI unit: 7.7% by mass, CMI unit: 13.7% by mass, and DDA unit: 1.3% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Comparative Example 1]
480 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 400.0 kg of metaxylene, and 0.45 kg of n-octyl mercaptan were charged. Except for this, resin pellets were obtained in the same manner as in Example 1.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 134 ° C.
The composition determined by NMR was MMA unit: 78.9% by mass, PMI unit: 7.6% by mass, and CMI unit: 13.5% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Comparative Example 2]
480 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 400.0 kg of metaxylene, and 0.45 kg of n-octyl mercaptan were charged. Except for this, resin pellets were obtained in the same manner as in Example 3.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 134 ° C.
The composition determined by NMR was MMA unit: 78.6% by mass, PMI unit: 7.7% by mass, and CMI unit: 13.7% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Comparative Example 3]
468 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 12 kg of ethyl acrylate (EA), 400.0 kg of metaxylene, and 0.45 kg. Resin pellets were obtained in the same manner as in Example 3 except that n-octyl mercaptan was charged.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 127 ° C.
The composition determined by NMR was MMA unit: 77.0% by mass, PMI unit: 7.8% by mass, CMI unit: 13.3% by mass, and EA unit: 1.9% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Comparative Example 4]
480 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), 78 kg of N-cyclohexylmaleimide (CMI), 12 kg of butyl acrylate (BA), 400.0 kg of metaxylene, and 0.45 kg. Resin pellets were obtained in the same manner as in Example 3 except that n-octyl mercaptan was charged.
The weight average molecular weight of the obtained pellets was 140,000, and the glass transition temperature was 125 ° C.
The composition determined by NMR was MMA unit: 77.3% by mass, PMI unit: 7.7% by mass, CMI unit: 13.2% by mass, and BA unit: 1.8% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.

[Comparative Example 5]
420 kg of methyl methacrylate (MMA), 42.0 kg of N-phenylmaleimide (PMI), in a 1.25 m ³ reaction kettle equipped with a stirrer equipped with paddle blades, a temperature sensor, a cooling tube, and a nitrogen introduction tube. 78 kg of N-cyclohexylmaleimide (CMI), 60 kg of n-hexyl acrylate (HA), 400.0 kg of metaxylene, and 0.45 kg of n-octyl mercaptan were charged and dissolved to prepare a raw material solution. The temperature was raised to 125 ° C. with stirring while passing nitrogen through it.
Separately, an initiator feed solution prepared by mixing 0.60 kg of perhexa C-75 and 1.45 kg of metaxylene was prepared.
When the raw material solution reached 127 ° C., the feed (addition) of the initiator feed solution (polymerization initiator mixed solution) was started with the profiles (1) to (4).
(1) 0.0 to 0.5 hours: Feed rate 0.38 kg / hour (2) 0.5 to 1.0 hours: Feed rate 0.19 kg / hour (3) 1.0 to 4.0 hours: Feed rate 0.13 kg / hour (4) 4.0-7.0 hours: Feed rate 0.45 kg / hour After feeding the initiator over a total of 7 hours (B time = 7 hours), react for another 1 hour. The polymerization reaction was continued from the start of addition of the initiator to 8 hours after the start of addition.
During the polymerization reaction, the internal temperature was controlled at 127 ± 2 ° C. When the polymerization conversion rate of the obtained polymerization solution was measured, it was MMA: 95.0%, PMI: 97.3%, CMI: 93.5%, DDA: 90.0%. As a whole, the polymerization conversion rate was 94.5%.
Irganox 1010: 0.05 parts by mass and Adecaster 1178: 0.05 parts by mass were added to 100 parts by mass of the polymerization solution obtained above, and after stirring for 30 minutes, 4 fore vents and 1 back vent were added. Using a φ42 mm devolatilization extruder, the volatilization treatment was carried out at 140 rpm at 10 kg / hour in terms of resin amount to obtain pellets of a methacrylic resin composition.
The weight average molecular weight of the obtained pellets was 130,000, and the glass transition temperature was 111 ° C.
The composition determined by NMR was MMA unit: 71.2% by mass, PMI unit: 7.4% by mass, CMI unit: 13.2% by mass, and HA unit: 8.2% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.
The manufacturing method in Comparative Example 5 did not satisfy the above-mentioned manufacturing method condition (iii).

[Comparative Example 6]
7.20 kg of methyl methacrylate (MMA), 0.720 kg of N-phenylmaleimide (PMI), 7.20 kg of toluene, 0.0072 kg of phosphorous acid in a 20 L stainless steel reaction kettle with paddle wings. After charging dimethyl acid and 0.0288 kg of t-dodecyl mercaptan and bubbling nitrogen gas for 10 minutes with stirring at 100 rpm, the temperature was started in a nitrogen atmosphere. When the temperature in the reaction vessel reaches 100 ° C., t-butylperoxyisopropyl carbonate (3000 mass ppm based on 100 parts by mass of the total amount of all monomers) is added to the reaction vessel, and the polymerization temperature is 105 to 110 ° C. , The polymerization reaction was carried out under reflux for a total of 15 hours.
Next, the obtained polymerization solution was supplied to a 42 mm twin-screw extruder with a vent whose cylinder temperature was controlled to 240 ° C., vacuum devolatile from the vent port, and the extruded strands were pelletized to obtain resin pellets.
The weight average molecular weight of the obtained pellets was 120,000, and the glass transition temperature was 128 ° C.
The composition obtained by NMR was MMA unit: 90% by mass and PMI unit: 10% by mass.
The above physical property evaluation was carried out using the obtained pellets. The evaluation results are shown in Table 1.
The manufacturing method in Comparative Example 6 did not satisfy the condition (i) of the above-mentioned manufacturing method.

As shown in Table 1, it can be seen that those having a weight average molecular weight within a predetermined range and a content of each unit within a predetermined range have excellent thermal stability and the like.

The present invention can provide a methacrylic resin having excellent heat resistance, thermal stability, and moldability, a methacrylic resin composition containing the same, a film containing the same, and a method for producing the same.
The present invention relates to household products, OA equipment, AV equipment, battery electrical equipment, lighting equipment, tail lamps, meter covers, head lamps, light guide rods, lenses and other automobile parts, housings, sanitary ware substitutes and other sanitary applications. , Liquid crystal display, plasma display, organic EL display, field emission display, light guide plate, diffuser plate, polarizing plate protective film, 1/4 wavelength plate, 1/2 wavelength plate, viewing angle control used for displays such as rear projection television. Phase difference films such as films and liquid crystal optical compensation films, transparent substrates such as display front panels, display substrates, lenses and touch panels, transparent substrates used for decorative films and solar cells, optical communication systems, optical exchange systems, optical In the field of measurement systems, it has industrial potential as a waveguide, a lens, an optical fiber, a coating material for an optical fiber, an LED lens, a lens cover, and the like.

Claims (12)

Following general formula (1) in represented Ru monomer unit (A): and from 46 to 96.5 wt%,

(In the formula (1), R ¹ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R ² represents a group having 1 to 3 carbon atoms.)
Structural unit (B) having a ring structure in the main chain: 3 to 30% by mass,
(Meta) acrylic acid ester monomer unit (C) represented by the following general formula (I): 0.5 to 8% by mass,

(In the formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an organic group having 6 to 20 carbon atoms (excluding phenyl group and benzyl group).
Other vinyl-based monomer unit (D) copolymerizable with the methacrylic acid ester monomer: 0 to 20% by mass,
The following conditions (1) to (2) and (4) are satisfied.
(1) The weight average molecular weight measured by gel permeation chromatography (GPC) is 65,000 to 300,000.
(2) The content of the (B) structural unit is 45 to 100% by mass, where the total amount of the (B) structural unit and the (D) monomer unit is 100% by mass.
(4) The content of the component having a weight average molecular weight of 10,000 or less measured by gel permeation chromatography (GPC) is 0.1 to 5.0% by mass, assuming that the methacrylic resin is 100% by mass.
A methacrylic resin characterized by this. Furthermore, the following condition (3) is satisfied.
(3) When the GC / MS measurement is carried out, the total content of the components detected in the holding time of 22 to 32 minutes is 0.01 to 0.40 mass with the methacrylic resin as 100% by mass. %.
The methacrylic resin according to claim 1. The methacrylic resin according to claim 1 or 2 , wherein the glass transition temperature is 115 ° C. or higher. The structural unit (B) is a maleimide-based structural unit (B-1), a glutaric anhydride-based structural unit (B-2), a glutarimide-based structural unit (B-3), and a lactone ring structural unit (B-). The methacryl-based resin according to any one of claims 1 to 3 , which contains at least one structural unit selected from the group consisting of 4). A methacrylic resin composition, which comprises the methacrylic resin according to any one of claims 1 to 4 . The methacrylic resin composition according to claim 5, further comprising 0.01 to 5 parts by mass of a heat stabilizer with respect to 100 parts by mass of the methacrylic resin. The methacrylic resin composition according to claim 5 or 6, further comprising 0.01 to 5 parts by mass of an ultraviolet absorber with respect to 100 parts by mass of the methacrylic resin. A display front plate comprising the methacrylic resin composition according to any one of claims 5 to 7 . An optical lens comprising the methacrylic resin composition according to any one of claims 5 to 7 . A light guide plate comprising the methacrylic resin composition according to any one of claims 5 to 7 . A meter panel comprising the methacrylic resin composition according to any one of claims 5 to 7 . An in-vehicle center console comprising the methacrylic resin composition according to any one of claims 5 to 7 .

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