JP2021015255A - Monitoring camera lens and lens cover - Google Patents

Abstract

To provide a monitoring camera lens and a cover that contain a methacryl-based resin composition with an excellent heat resistance, weather resistance, optical characteristic, a color phase, and a formation processing property.SOLUTION: The monitoring camera lens and the lens cover contains a methacryl-based resin composition in which the degree of change (ΔYI) is 20 or smaller, the (ΔYI) being the rate of change of a YI value (220 mm-long optical path YI value (270 seconds)) of a 220-mm long optical path measured according to JIS K7105 for a test piece manufactured under the condition that the cycle time of an injection molding is 270 seconds to a YI value (220 mm-long optical path YI value (45 seconds)) of a 220-mm long optical path measured according to JIS K7105 for a test piece with a 3-mm thickness, a 20-mm width, and a 220-mm length manufactured under the condition that the cycle time of an injection molding is 45 seconds, represented by formula (I).SELECTED DRAWING: None

Description

The present invention relates to a lens for a surveillance camera and a lens cover.

Due to its high transparency, methacrylic resins represented by polymethylmethacrylate (PMMA) have traditionally been used in the fields of optical materials, vehicle parts, building materials, lenses, household products, OA equipment, lighting equipment, etc. Widely used. Among them, in the field of optical members such as light guide plates and light guides represented by thick lenses, methacrylic is considered because of the ease of molding, which is a feature of thermoplastic resins, and the outstanding transparency among the thermoplastic resins. Many based resins are used.

On the other hand, in the surveillance camera lens and the cover, a transparent resin having heat resistance to withstand the heat generation of the internal motor and the like and a certain impact resistance because it is used outdoors is required.

In view of the above circumstances, a polycarbonate resin may be used as a material for the surveillance camera lens and the cover from the viewpoint of heat resistance and impact resistance. However, polycarbonate-based resins are inferior in weather resistance to methacrylic resins, especially when used outdoors, so a larger amount of UV absorber must be added, and if the UV absorber is insufficient, it will turn yellow. Therefore, there is a problem that the function as an optical member is not fulfilled.

Therefore, for polycarbonate-based resins, the weather resistance is improved by blending an ultraviolet absorber, but the blending of an ultraviolet absorber tends to reduce the light transmittance, and the above-mentioned long optical path design It has a problem that it cannot meet the demands for conversion and improvement of brightness. Further, polycarbonate has a problem that visibility is deteriorated due to high birefringence.

Further, in applications such as vehicle members where high transparency, that is, high optical path transmittance is not required, a methacrylic copolymer resin containing a methacrylic acid-based monomer unit and a monomer unit having a cyclic structure is used. It is known to be used (see, for example, Patent Document 1).
However, the methacrylic copolymer resin disclosed in Patent Document 1 has a problem that the molding processability is not sufficient and it is not suitable for producing a fine or thin optical member such as a lens. ..
Further, a technique for improving the long optical path transmittance by using a resin using a methacrylic acid ester-based monomer, a maleimide-based monomer, and a styrene-based monomer is disclosed (see, for example, Patent Document 2).
According to the technique of Patent Document 2, the long optical path transmittance is significantly improved, but there is a problem that further improvement is necessary from the viewpoint of long-term hue stability and improvement of whiteness in the long optical path. doing.

Japanese Unexamined Patent Publication No. 2014-024361 JP-A-2016-210963

As described above, in the surveillance camera lens and the cover, a resin material having a good balance of heat resistance, weather resistance, optical characteristics, hue and moldability is required, and the above-mentioned conventionally proposed resin materials are still available. It is inadequate and requires a higher level of properties.

Therefore, an object of the present invention is to provide a surveillance camera lens and a cover containing a methacrylic resin composition having excellent heat resistance, weather resistance, optical properties, hue and molding processability.

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は、水素原子、炭素数が１〜１２の脂肪族炭化水素基又は炭素数が１〜１２の芳香族炭化水素基を表す。Ｒの脂肪族炭化水素基及び芳香族炭化水素基は、それぞれ炭素原子上に硫黄原子、窒素原子、酸素原子、リン原子を有していてもよい。また、Ｒ’は、炭素数１〜１２の脂肪族炭化水素基又は炭素数６〜１８の芳香族炭化水素基を表す。Ｒ’の脂肪族炭化水素基及び芳香族炭化水素基は、それぞれ炭素原子上に硫黄原子、窒素原子、酸素原子、リン原子を有していてもよい。）

（式（２）中、Ｒ、Ｒ’、Ｒ’’は、それぞれ独立に、水素原子、炭素数が１〜１２の脂肪族炭化水素基又は炭素数が１〜１２の芳香族炭化水素基を表す。Ｒ、Ｒ’、Ｒ’’の脂肪族炭化水素基及び芳香族炭化水素基は、それぞれ炭素原子上に硫黄原子、窒素原子、酸素原子、リン原子を有していてもよい。また、Ｒ’、Ｒ’’は、互いに結合して環を形成していてもよい。）
〔４〕
前記メタクリル系樹脂組成物における前記主鎖に環構造を有する構造単位（Ｂ）の含有量の前記メタクリル系樹脂組成物における前記（Ｄ）成分の含有量に対する割合（（Ｂ）／（Ｄ））が２５以上１０００以下である、〔３〕に記載の監視カメラ用レンズ及びレンズカバー。
〔５〕
前記メタクリル系樹脂組成物の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〕又は〔３〕に記載の監視カメラ用レンズ及びレンズカバー。
〔６〕
前記メタクリル系樹脂（ａ）が、メタクリル酸エステル単量体単位（Ａ）：５０〜９７質量％と、主鎖に環構造を有する構造単位（Ｂ）：３〜３０質量％と、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（Ｃ）：０〜２０質量％とを含むを含む、
下記（Ｉ）及び（ＩＩ）の条件を満たす
メタクリル系樹脂組成物を含む、〔３〕〜〔５〕のいずれかに記載の監視カメラ用レンズ及びレンズカバー。
〔７〕
前記主鎖に環構造を有する構造単位（Ｂ）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）、ラクトン環構造単位（Ｂ−４）、及び酸無水物構造単位（Ｂ−５）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、〔３〕〜〔６〕のいずれかに記載の監視カメラレンズ及びレンズカバー。
〔８〕
厚みが０．０３〜３ｍｍである、〔３〕〜〔７〕のいずれかに記載の監視カメラ用レンズ及びレンズカバー。 [1]
A 220 mm long optical path YI value (220 mm) measured in accordance with JIS K7105 for a test piece having a thickness of 3 mm, a width of 20 mm, and a length of 220 mm, which is represented by the following formula (I) and has a cycle time of injection molding of 45 seconds. 220 mm long optical path YI value (220 mm long optical path YI value (270 seconds)) measured in accordance with JIS K7105 for a test piece prepared with an injection molding cycle time of 270 seconds with respect to the long optical path YI value (45 seconds)). A lens and a lens cover for a surveillance camera, which comprises a methacrylic resin composition having a degree of change (ΔYI) of 20 or less.
ΔYI = {220 mm long optical path YI value (270 seconds) -220 mm long optical path YI value (45 seconds)} / 220 mm long optical path YI value (45 seconds) ... (I)
[2]
The lens for a surveillance camera according to [1], wherein the color difference ΔE * measured according to JIS Z8730 before and after the 2040 hour exposure test using the method of JIS K7350-4 using a test piece having a thickness of 3 mm is 3 or less. And lens cover.
[3]
The methacrylic resin composition contains 100 parts by mass of a methacrylic resin (a) containing a structural unit (B) having a ring structure in the main chain, and a compound (b) represented by the following general formula (1) or (2). ): The lens and lens cover for a surveillance camera according to [1] or [2], which contains 0.001 to 0.2 parts by mass.

(In the formula (1), R represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and aromatic group of R. The group hydrocarbon group may have a sulfur atom, a nitrogen atom, an oxygen atom, and a phosphorus atom on the carbon atom, respectively. R'is an aliphatic hydrocarbon group having 1 to 12 carbon atoms or a carbon number of carbon atoms. Represents 6 to 18 aromatic hydrocarbon groups. Even if the aliphatic hydrocarbon group and the aromatic hydrocarbon group of R'have a sulfur atom, a nitrogen atom, an oxygen atom, and a phosphorus atom on carbon atoms, respectively. Good.)

In the formula (2), R, R', and R'' each independently contain a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group of R, R'and R'' may have a sulfur atom, a nitrogen atom, an oxygen atom and a phosphorus atom on the carbon atom, respectively. R'and R'' may be combined with each other to form a ring.)
[4]
Ratio of the content of the structural unit (B) having a ring structure in the main chain in the methacrylic resin composition to the content of the component (D) in the methacrylic resin composition ((B) / (D)) The surveillance camera lens and lens cover according to [3], wherein is 25 or more and 1000 or less.
[5]
The lens and lens cover for a surveillance camera according to [2] or [3], wherein the weight average molecular weight of the methacrylic resin composition measured by gel permeation chromatography (GPC) is 65,000 to 300,000.
[6]
The methacrylic acid resin (a) contains a methacrylic acid ester monomer unit (A): 50 to 97% by mass, a structural unit (B) having a ring structure in the main chain: 3 to 30% by mass, and a methacrylic acid ester. Other vinyl-based monomer units (C) copolymerizable with the monomer: containing 0 to 20% by mass,
The lens and lens cover for a surveillance camera according to any one of [3] to [5], which comprises a methacrylic resin composition satisfying the following conditions (I) and (II).
[7]
The structural unit (B) having a ring structure in the main chain 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. The surveillance camera lens according to any one of [3] to [6], which comprises at least one structural unit selected from the group consisting of a ring structural unit (B-4) and an acid anhydride structural unit (B-5). And lens cover.
[8]
The lens and lens cover for a surveillance camera according to any one of [3] to [7], which have a thickness of 0.03 to 3 mm.

According to the present invention, it is possible to provide a surveillance camera lens and a cover containing a methacrylic resin composition having excellent heat resistance, weather resistance, optical properties, hue and molding processability.

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 is within the scope of the gist thereof. It can be modified in various ways.
In the following, the structural units constituting the polymer forming the methacrylic resin contained in the methacrylic resin composition used in the present embodiment are referred to as "~ monomer unit" and / or a plurality of the "~". It is called "~ structural unit" including "monomer unit".
In addition, the constituent material of such "~ monomer unit" may be simply described as "~ monomer" by omitting the "unit".

(Methacrylic resin composition)
The methacryl-based resin composition used in the present embodiment is according to JIS K7105 for a test piece having a thickness of 3 mm, a width of 20 mm, and a length of 220 mm, which is represented by the following formula (I) and is prepared with an injection molding cycle time of 45 seconds. 220 mm long optical path YI value measured according to JIS K7105 for a test piece prepared with an injection molding cycle time of 270 seconds with respect to the 220 mm long optical path YI value (220 mm long optical path YI value (45 seconds)) measured in accordance with the regulations. The degree of change (ΔYI) of (220 mm long optical path YI value (270 seconds)) is 20 or less.
ΔYI = {220 mm long optical path YI value (270 seconds) -220 mm long optical path YI value (45 seconds)} / 220 mm long optical path YI value (45 seconds) ... (I)

The methacrylic resin composition of the present embodiment may contain a methacrylic resin, compound (D), other components and the like.

(Methacrylic resin)
The methacrylic acid resin (a) used in the methacrylic acid resin composition used in the present embodiment is not particularly limited in its composition, but has a methacrylic acid ester monomer unit (A): 50 to 97% by mass, which is ringed in the main chain. It may contain a structural unit (B) having a structure: 3 to 30% by mass and another vinyl-based monomer unit (C) capable of copolymerizing with a methacrylic acid ester monomer: 0 to 20% by mass. ..

<Methyl ester monomer unit (A)>
The methacrylic ester monomer unit (A) (hereinafter, may be referred to as (A) monomer unit) constituting the methacrylic resin is a monomer represented by the following general formula (a). The unit is preferably used.

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

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

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

The methacrylic acid ester monomer is not limited to the following, and is, for example, butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and methacrylic acid. Examples thereof include acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, and methacrylic acid (2,2,2-trifluoroethyl).
The methacrylic acid ester monomer is preferably methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, or benzyl methacrylate from the viewpoints of heat resistance, handleability, and optical properties, and is easy to obtain. Therefore, methyl methacrylate is preferable.
As the methacrylic acid ester monomer, only one kind may be used alone, or two or more kinds may be used in combination.

The methacrylic acid ester monomer unit (A) of the methacrylic resin is a structural unit (B) having a ring structure in the main chain, which will be described later, to monitor the methacrylic resin composition used in the present embodiment and the present embodiment. From the viewpoint of imparting sufficient heat resistance to the camera lens and the lens cover and imparting a good hue, it is necessary to contain 50% by mass or more and 97% by mass or less in the methacrylic resin. The content is preferably 55% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more.
Further, the content of the methacrylic ester monomer unit (A) in the methacrylic resin is preferably 96% by mass or less, more preferably 95% by mass, when it is necessary to impart particularly high heat resistance. It is as follows.

<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 is a maleimide-based structural unit (B) from the viewpoint of heat resistance. -1), glutaric acid anhydride-based structural unit (B-2), glutarimide-based structural unit (B-3), lactone ring structural unit (B-4), and anhydrous oxide (B-5) It is preferable to include at least one structural unit selected from the above.
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, the structural unit represented by the following general formula (c) is preferably used.

In the general formula (c), R ¹ has a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and a carbon number of carbon atoms. It represents any one selected from the group consisting of 6 to 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 limited to the following, but for example, maleimide; N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide and the like. N-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.
The monomer for forming the maleimide-based structural unit (B-1) is preferably N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N from the viewpoint of imparting heat resistance and moisture heat resistance. Examples thereof include − (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, and N- (p-chlorophenyl) maleimide, and more preferably N-cyclohexylmaleimide from the viewpoint of easy availability and imparting heat resistance. N-phenylmaleimide is mentioned, and more preferably N-phenylmaleimide is 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 Acid Anhydride System Structural Unit (B-2)]
The glutaric anhydride-based structural unit (B-2) constituting the methacrylic acid-based resin may be formed after the polymerization of the methacrylic acid-based resin.
As the structural unit (B-2), the structural unit represented by the following general formula (d) is preferably used.

In the general formula (d), 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 substituted with a hydroxyl group. May be.
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 (e) 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 (e), 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 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 (e) may remain unreacted in the methacrylic resin.

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

In the general formula (f), 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 substituted with a hydroxyl group. May be.
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 above-mentioned glutarimide-based structural unit (B-3), 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 50% by mass, more preferably 3 to 30% by mass, still more preferably 3 with 100% by mass of the methacrylic resin. ~ 20% 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 the 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 of copolymerizing a methacrylic acid ester and / or methacrylic acid and then reacting ammonia or an amine with urea or an unsubstituted urea reaction at a high temperature. Methyl methacrylate-methacrylic acrylate. It can be obtained by a known method such as a method of reacting an acid-styrene copolymer or a methyl methacrylate-styrene copolymer with ammonia or an amine, a method of reacting a polymethacrylic acid anhydride with ammonia or an 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. Can also form the glutarimide-based structural unit (B-3).

Further, as another preferable method for forming the glutarimide-based structural unit (B-3), a (meth) acrylic acid ester and, if necessary, an aromatic vinyl monomer or another vinyl monomer were polymerized. After that, an imidization reaction may be carried out to obtain a resin containing a glutarimide-based structural unit (B-3).
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, for example, 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, and examples thereof include a method using an extruder, a horizontal twin-screw reactor, and a batch reaction tank. 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 a methacrylic resin containing the glutarimide-based structural unit (B-3), an esterification step of treating with an esterifying agent can be included in addition to the step of the imidization reaction.
By including the esterification step, the carboxyl group contained in the methacrylic 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 methacrylic 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 may be formed after the polymerization of the methacrylic resin.
As the structural unit (B-4), the structural unit represented by the following general formula (g) is preferably used.

In the general formula (g), R ¹ , R ² , and R ³ each 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 producing the polymer containing the lactone ring structural unit (B-4) is not particularly limited, but is, for example, a monomer having a hydroxyl group in the side chain, specifically represented by the following general formula (chi). Obtained after copolymerizing a monomer having such a structure (methyl 2- (hydroxymethyl) acrylate, etc.) and a monomer having an ester group such as the above-mentioned methacrylate-based monomer (A). Examples thereof include a method of producing the copolymer by heat-treating the copolymer in the presence / absence of a predetermined catalyst and introducing a lactone ring structure into the polymer.

In the general formula (h), 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 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 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 (chi) may remain unreacted in the methacrylic resin.

[Acid anhydride structural unit (B-5)]
The acid anhydride structural unit (B-5) constituting the methacrylic resin is, for example, an acid anhydride such as maleic anhydride, the acid anhydride and a linear or branched alcohol having 1 to 20 carbon atoms. It can be formed by preferably using a half ester, α, β-ethylenic anhydride, or the like.

The structural unit (B) having a ring structure in the main chain contained in the above-mentioned methacrylic resin includes a maleimide-based structural unit (B-1) and a glutarimide-based structural unit (B-) in terms of thermal stability and moldability. It is preferable to include at least one structural unit selected from the group consisting of 3), and it is more preferable to include a maleimide-based structural unit (B-1).
Among the maleimide-based structural units (B-1), considering the availability, N-cyclohexylmaleimide-based structural units and / or N-aryl-substituted maleimide-based structural units are preferable, and from the viewpoint of hue of the molded product. Therefore, N-cyclohexylmaleimide-based structural units are more preferable.

The content of the structural unit (B) having a ring structure in the main chain in the methacrylic resin is 3% by mass or more from the viewpoint of imparting heat resistance and thermal stability of the methacrylic resin composition used in the present embodiment. Yes, preferably 4% by mass or more, and more preferably 5% 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 30% by mass or less. Is 25% by mass or less, more preferably 20% by mass or less, still more preferably 14% by mass or less, still more preferably 10% by mass or less.

In particular, when a maleimide-based structural unit (B-1) is used as the structural unit (B) having a ring structure in the main chain, the content of the maleimide-based structural unit (B-1) is high in heat resistance and thermal stability. From the viewpoint, when the total amount of the methacrylic acid ester monomer unit (A) and the structural unit (B) having a ring structure in the main chain is 100% by mass, it is preferably less than 50% by mass, more preferably 40. It is less than mass%, more preferably less than 35% by mass, even more preferably 1 to 30% by mass, and even more preferably 2 to 20% by mass.

<Other vinyl-based monomer unit (C) copolymerizable with the methacrylic ester monomer>
In the methacrylic resin, other vinyl-based monomer units are copolymerized from the viewpoint of obtaining a resin having better weather resistance, fluidity, chemical resistance, thermal stability, etc., and imparting other properties. It is preferable to let it.
For example, an acrylic acid ester monomer unit (C-1), a vinyl cyanide-based monomer unit (C-2), and the like can be mentioned.

[Acrylic ester monomer unit (C-1)]
The monomer used for forming the acrylic acid ester monomer unit (C-1) constituting the methacrylic resin is not particularly limited, but is represented by the following general formula (i). Acrylic ester monomers are preferred.

In the general formula (i), R ¹ represents a hydrogen atom or an alkoxy group having 1 to 12 carbon atoms, and R ² is an alkyl group having 1 to 18 carbon atoms and a cycloalkyl having 1 to 18 carbon atoms. Represents a group, an aryl group having 1 to 18 carbon atoms.

The monomer for forming the acrylic acid ester monomer unit (C-1) is the methacrylic resin used in the present embodiment from the viewpoint of enhancing weather resistance, heat resistance, fluidity, and thermal stability. , Methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate and the like are preferable, and acrylate is more preferable. Methyl, ethyl acrylate, and n-butyl acrylate, and methyl acrylate and ethyl acrylate are more preferable from the viewpoint of availability.
As the acrylic acid ester monomer unit (C-1), only one type may be used alone, or two or more types may be used in combination.
When the acrylic acid ester monomer unit (C-1) is used, the total content of the (A) monomer unit and the (B) structural unit is 100 from the viewpoint of heat resistance and thermal stability. In terms of mass%, it is preferably 5% by mass or less, and more preferably 3% by mass or less.

[Vinyl cyanide monomer unit (C-2)]
In the methacrylic resin, the vinyl cyanide-based monomer unit (C-2) is preferable as the (C) monomer unit from the viewpoint of easily obtaining and obtaining a resin having further excellent chemical resistance. ..
The monomer used for forming the vinylidene cyanide monomer unit (C-2) constituting the methacrylic resin is not limited to the following, but for example, acrylonitrile, methacrylonitrile, and the like. Examples thereof include vinylidene cyanide, and among them, acrylonitrile is preferable from the viewpoint of easy availability and imparting chemical resistance.
As the vinyl cyanide-based monomer unit (C-2), only one type may be used alone, or two or more types may be used in combination.
When the vinyl cyanide-based monomer unit (C-2) 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.

[Monomer units (C-3) other than (C-1) to (C-2)]
The monomer used for forming the monomer unit (C-3) other than (C-1) to (C-2) constituting the methacrylic resin is not limited to the following. For example, amides such as styrene, acrylamide, and methacrylic amide; 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 the hydroxyl groups at both ends of the oligomer are esterified with acrylic acid or methacrylic acid; the hydroxyl groups of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate are esterified with acrylic acid or methacrylic acid. Acrylate: A polyhydric alcohol derivative such as trimethylolpropane or pentaerythritol is esterified with acrylic acid or methacrylic acid; a polyfunctional monomer such as divinylbenzene and the like can be mentioned.

Among the monomers used to form the above-mentioned (C) monomer unit, at least one selected from the group consisting of methyl acrylate, ethyl acrylate, and acrylonitrile is preferable from the viewpoint of availability. .. Further, from the viewpoint of maintaining the transmittance and hue in a long optical path having a length of 100 mm or more, methyl (C) acrylate is preferable.

The content of the other vinyl-based monomer unit (C) copolymerizable with the methacrylic acid ester monomer is 100% by mass of the methacrylic 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 the styrene monomer unit is used as the (C) monomer unit, the content of the styrene monomer unit is 0 to 6 with the methacrylic resin as 100% by mass from the viewpoint of improving the weather resistance. It is preferably 0 to 5% by mass, more preferably 0 to 3% by mass or less.
In particular, when a crosslinkable polyfunctional (meth) acrylate having a plurality of reactive double bonds is used as the (C) monomer unit, the content of the (C) monomer unit is determined from the viewpoint of fluidity. , 0.5% by mass or less, more preferably 0.3% by mass or less, still more preferably 0.2% by mass or less.

(Compound (D))
The compound (D) that can be contained in the methacrylic resin composition of the present embodiment is represented by the following general formula (1) or (2).

Here, R represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group of R may have a sulfur atom, a nitrogen atom, an oxygen atom and a phosphorus atom on the carbon atom, respectively.
Further, R'represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group of R'may have a sulfur atom, a nitrogen atom, an oxygen atom and a phosphorus atom on the carbon atom, respectively.

Here, R, R ″, and R ″ independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group of R, R ″ and R ″ may have a sulfur atom, a nitrogen atom, an oxygen atom and a phosphorus atom on carbon atoms, respectively. Further, R ″ and R ″ may be bonded to each other to form a ring.

From the viewpoint of suppressing the degree of change in the YI value during long-term residence, the compound (D) preferably has a succinimide skeleton of the above formula (1), and R is a hydrogen atom in the above formula (1). It is more preferable to have a 3-hydroxysuccinimide skeleton.

From the viewpoint of suppressing the degree of change in the YI value during molding when repeatedly exposed to high temperature for a long time, the content of the compound (D) is 0.001 part by mass or more with respect to 100 parts by mass of the methacrylic resin. More preferably 0.005 parts by mass or more, still more preferably 0.01 parts by mass or more, even more preferably 0.015 parts by mass or more, still more preferably 0.02 parts by mass or more, particularly preferably. It is 0.03 part by mass or more.
Further, from the viewpoint of maintaining high transmittance and high whiteness in a long optical path, it is preferably 0.2 parts by mass or less, more preferably 0.15% by mass or less, and further preferably 0.12% by mass. Hereinafter, it is even more preferably 0.11% by mass or less, and even more preferably 0.1% by mass or less.
By containing a certain amount of the compound (D), thermal decomposition is suppressed when the methacrylic resin is placed in a high temperature environment, and the effects of reducing yellowing in the long optical path and improving the transmittance stability can be obtained. ..

In the present embodiment, the mass ratio of the compound (D) to the structural unit (B) having a ring structure in the main chain in the methacrylic resin composition is the stability of YI during continuous molding and the long optical path. The range is 25 ≦ (B) / (D) ≦ 1000 from the viewpoint of reducing yellowing, improving the transmittance stability, and reducing silver streaks and the like during molding.
The yellowing dependence of the thickness of the methacrylic resin composition from 3 mm to 220 mm, that is, the YI value between the thicknesses when measuring the YI value in the molded piece having a predetermined thickness between 3 mm and 220 mm. From the viewpoint of reducing the change value of, the (B) / (D) is preferably 800 or less, more preferably 700 or less, still more preferably 600 or less, and even more preferably 500 or less. Further, the above (B) / (D) is preferably 30 or more, more preferably 45 or more, still more preferably 50 or more, from the viewpoint of heat resistance of the methacrylic resin composition.

The characteristics of the methacrylic resin will be described below.

<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 from the viewpoint of obtaining a methacrylic resin having further excellent mechanical strength, solvent resistance, and fluidity.
By setting the weight average molecular weight of the methacrylic resin within the above range, the methacrylic resin and the methacrylic resin composition used in 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 200,000 or less, still more preferably 15 from the viewpoint of ensuring fluidity during molding, reducing strain during molding, and imparting long optical path transmittance. It is 10,000 or less, more preferably 130,000 or less, and even more preferably 120,000 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 from the viewpoint 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 1.6 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.

(Manufacturing method of methacrylic resin)
The method for producing the methacrylic resin is not particularly limited as long as the above-mentioned methacrylic resin can be obtained.

The methacrylic resin can be copolymerized with the methacrylic acid ester monomer unit (A), the structural unit (B) having a ring structure in the main chain, and, if necessary, the methacrylic acid ester monomer described above. Each monomer for forming the other vinyl-based monomer unit (C) can be produced by a massive polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, or an emulsion polymerization method.
A massive polymerization method, a solution polymerization method, and a suspension polymerization method are preferably used, more preferably a solution polymerization method and a suspension polymerization method, and further preferably a suspension polymerization method.
Further, the methacrylic resin may be produced by a continuous type or a batch type.
In the method for producing a methacrylic resin, it is preferable to polymerize the monomer by radical polymerization.

A polymerization initiator may be used in the polymerization reaction of the methacrylic resin.
The polymerization initiator may be one that decomposes at the polymerization temperature to generate active radicals, but it is necessary to achieve the required polymerization conversion rate within the residence time, and the half-life at the polymerization temperature is 0. A polymerization initiator is selected that satisfies 6 to 60 minutes, preferably 1 to 30 minutes. However, even for a polymerization initiator having a half-life of more than 60 minutes at the polymerization temperature, it can be 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 be used. 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.

The above-mentioned radical polymerization initiator may be used as a redox-based initiator in combination with an appropriate reducing agent.
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 total molecular weight tends to decrease by using a large amount of the polymerization initiator, and the calorific value at the time of 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. It is more preferably 0.001 to 0.8 parts by mass, and further 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 polymerization reaction of the methacrylic resin, a chain transfer agent, an inifata, or the like can be optionally used as the molecular weight adjusting agent.
In the process for producing a methacrylic resin, 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.
Chain transfer agents and inifatas include, but are not limited to, chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine; dithiocarbamates, triphenylmethylazobenzene, tetraphenylethane derivatives, etc. The molecular weight can be controlled by using an iniferta or the like, and further, the molecular weight can be controlled by adjusting the addition amount of these chain transfer agents or the inifata.

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, 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, examples of other molecular weight control methods 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, 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. The type and method of use are not limited as long as the effects of the present invention can be exhibited.

<Manufacturing method by suspension polymerization method>
When a methacrylic resin is produced by suspension polymerization such as an organic suspension polymerization method or an inorganic suspension polymerization method, particles are subjected to a polymerization step, a washing step, a dehydration step, and a drying step using a stirring device described later. Manufactures a methacrylic resin.
Usually, an aqueous suspension polymerization method using water as a medium is preferably used.

[Polymerization process]
In the polymerization step, a predetermined stirrer is used, and a monomer, a suspending agent, a polymerization initiator, and other additives as raw materials are appropriately supplied into the stirrer to carry out the polymerization. Obtain a slurry of based resin.
The stirring device used in the polymerization process for obtaining a methacrylic resin by the suspension polymerization method includes an inclined paddle blade, a flat paddle blade, a propeller blade, an anchor blade, a Faudler blade (retreating blade), a turbine blade, and a bull margin. Stirrer with stirring blades such as blades, max blend blades, full zone blades, ribbon blades, supermix blades, intermig blades, special blades, axial flow blades, stirring equipment with excavator blades inside, chopper blades inside Examples thereof include a stirring device and a known stirring device such as a stirring device having a rotating disk such as a disk type, a notched disk type or a screw type inside.
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 an appropriate particle size can be obtained and a component having a particle size of less than 0.15 mm is contained. Considering that the amount can be reduced, polymerization stability, etc., it is preferably about 1 to 500 rpm.

The temperature at which the raw material mixture of the methacrylic resin is added may be as long as the effect of the present invention can be exhibited, and is preferably 0 ° C. or higher and lower than the boiling point of the raw material to be used. If the temperature is high, the raw material tends to volatilize during addition, so the composition of the copolymer that constitutes the obtained methacrylic resin changes. If the temperature is lower than 0 ° C, it takes time to raise the temperature after adding the raw material. Therefore, it is preferable to add the raw material mixture at a certain temperature. Specifically, it is preferably 0 ° C. or higher and 85 ° C. or lower, more preferably 10 ° C. or higher and 85 ° C. or lower, still more preferably 30 ° C. or higher and 85 ° C. or lower, and even more preferably 50 ° C. or higher and 80 ° C. or lower. Even more preferably, it is 60 ° C. or higher and 80 ° C. or lower.
The temperature in the suspension polymerization step is preferably 40 ° C. or higher and 90 ° C. or lower in consideration of productivity and the amount of aggregates produced. It is more preferably 50 ° C. or higher and 85 ° C. or lower, still more preferably 60 ° C. or higher and 85 ° C. or lower, and even more preferably 65 ° C. or higher and 83 ° C. or lower.

The polymerization time in suspension polymerization is preferably 20 minutes or more and 240 minutes or less from the viewpoint of effectively suppressing heat generation during polymerization, reducing the generation of aggregates and reducing residual monomers, which will be described later. It is more preferably 30 minutes or more and 210 minutes or less, still more preferably 45 minutes or more and 180 minutes or less, still more preferably 60 minutes or more and 180 minutes or less, and even more preferably 90 minutes or more and 150 minutes or less.

Further, from the viewpoint of reducing the residual monomer, it is preferable to raise the temperature to a temperature higher than the polymerization temperature after the polymerization step and hold the temperature for a certain period of time.
Since the degree of polymerization can be increased, the holding temperature is preferably a temperature higher than the polymerization temperature, and when the temperature is higher, the temperature is preferably 5 ° C. or higher than the polymerization temperature.
When the temperature is raised, it is preferably equal to or lower than the glass transition temperature of the methacrylic resin obtained from the viewpoint of preventing agglutination of the obtained polymer.
Specifically, it is 120 ° C. or lower, preferably 100 ° C. or lower, more preferably 80 ° C. or higher and 100 ° C. or lower, still more preferably 85 ° C. or higher and 100 ° C. or lower, still more preferably 88 ° C. or higher and 100 ° C. or lower, still more preferably. Is 90 ° C. or higher and 100 ° C. or lower.
By carrying out the polymerization according to the above-mentioned polymerization temperature and holding time, polymer particles having a small angle of repose can be produced after undergoing the drying step described later.
Considering the effect of reducing residual monomers, the time for maintaining the temperature after the temperature rise is preferably 15 minutes or more and 360 minutes or less, more preferably 30 minutes or more and 240 minutes or less, and further preferably 30 minutes or more and 180 minutes. Hereinafter, it is even more preferably 30 minutes or more and 150 minutes or less, and even more preferably 30 minutes or more and 120 minutes or less.

Further, for the purpose of reducing the residual monomer, an organic solvent can be used at the time of polymerization as long as the polymerization stability is not affected. The organic solvent that can be preferably used may be any solvent that can dissolve the obtained resin, and preferably an aromatic hydrocarbon solvent such as xylene, toluene, or ethylbenzene can be used.
When the total amount of the monomers used is 100 parts by mass, the amount used is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 8 parts by mass or less, and even more preferably. It is 6 parts by mass or less.

[Washing process]
The slurry of the methacrylic resin obtained through the above-mentioned polymerization step is preferably subjected to operations such as acid washing, water washing, and alkaline washing in order to remove the suspending agent.
The optimum number of times of performing these cleaning operations may be selected from the work efficiency and the removal efficiency of the suspending agent, and may be repeated once or a plurality of times.
The optimum temperature for washing may be selected in consideration of the removal efficiency of the suspending agent, the degree of coloring of the obtained copolymer, and the like, and is preferably 20 to 100 ° C. It is more preferably 30 to 95 ° C, still more preferably 40 to 95 ° C.
Further, the cleaning time per cleaning is preferably 10 to 180 minutes, more preferably 20 to 150 minutes, from the viewpoint of cleaning efficiency, the effect of reducing the angle of repose, and the simplicity of the process.

The pH of the washing liquid used at the time of washing may be in the range where the suspending agent can be removed, but is preferably pH 1 to 12.
The pH at the time of acid cleaning is preferably pH 1 to 5, more preferably pH 1.2 to 4, from the viewpoint of the removal efficiency of the suspending agent and the color tone of the obtained copolymer.
The acid used at that time may be any acid that can remove the suspending agent, and is not particularly specified, but conventionally known inorganic acids and organic acids can be used.
Examples of the acid preferably used include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid and the like as the inorganic acid, and each may be used in a diluted solution diluted with water or the like. Examples of the organic acid include those having a carboxyl group, a sulfo group, a hydroxy group, a thiol group, and an enol.
Considering the effect of removing the suspending agent and the color tone of the obtained resin, a nitric acid, sulfuric acid, and an organic acid having a carboxyl group are more preferable.

After the acid cleaning, it is preferable to further perform water washing or alkaline washing from the viewpoint of reducing the color tone and the angle of repose of the obtained polymer.
The pH of the alkaline solution when performing alkaline cleaning is preferably pH 7.1-12, more preferably pH 7.5-11, and even more preferably 7.5-10.5. As the alkaline component used for alkaline cleaning, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are preferably used. More preferably, it is an alkali metal hydroxide or an alkaline earth metal hydroxide, and more preferably, lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, or hydroxide. Calcium and barium hydroxide are even more preferable, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide are more preferable, and sodium hydroxide and potassium hydroxide are even more preferable. These alkaline components can be used by diluting with water or the like to adjust the pH.

[Dehydration process]
As a method of dehydrating the obtained polymer slurry of the methacrylic resin and separating the polymer particles, a conventionally known method can be applied.
For example, a dehydration method using a centrifuge that shakes off water using centrifugal force, a method of sucking and removing water on a porous belt or a filtration membrane, and a method of separating polymer particles and the like can be mentioned.

[Drying process]
The polymer of the methacrylic resin in the water-containing state obtained through the above-mentioned dehydration step can be dried and recovered by a known method.
For example, hot air drying that dries by sending hot air into the tank from a hot air blower, blow heater, etc., vacuum drying that dries by depressurizing the inside of the system and then heating it as needed, the obtained polymer Examples include barrel drying in which water is removed by rotating the material in a container, spin drying in which water is dried by using centrifugal force, and the like.
These methods may be used alone or in combination.
The water content of the obtained methacrylic resin is preferably 0.01% by mass to 1% by mass, more preferably 0.05% by mass to 1% by mass, in consideration of the handleability, color tone, etc. of the obtained methacrylic resin. , More preferably 0.1% by mass to 1% by mass, and even more preferably 0.27% by mass to 1% by mass.
The water content of the obtained resin can be measured by using the Karl Fischer method.

When a methacrylic resin is produced by using the suspension polymerization method described above, the obtained methacrylic resin is usually substantially spherical, but some aggregates may be formed.
The agglomerate refers to a residue remaining on the sieve when the obtained polymer is passed through a 1.68 mm mesh sieve.
When the agglomerates remain in the methacrylic resin, the color tone of the obtained methacrylic resin tends to deteriorate. From this point of view, the amount of aggregates in the methacrylic resin is preferably 1.2% by mass or less, more preferably 1.0% by mass or less.
The content of the agglomerates was determined by measuring the weight of what remained on the sieve through a 1.68 mm mesh sieve and drying it in a drying oven at 80 ° C. for 12 hours, and using the obtained mass as the total amount of the raw materials. The amount of agglomerates produced (% by mass) can be calculated by dividing by.

The average particle size of the methacrylic resin obtained by using the suspension polymerization method described above is preferably 0.1 mm or more in consideration of workability during molding and extrusion, and the molded piece obtained by molding. In consideration of the color tone of the above, it is more preferably 0.1 mm or more and 1 mm or less, further preferably 0.1 mm or more and 0.5 mm or less, and even more preferably 0.1 mm or more and 0.4 mm or less.
The average particle size is, for example, a sieve (JTS-200-45-44 (opening 500 μm), 34 (opening 425 μm), 35 (opening 355 μm), 36 (opening 300 μm) based on JIS-Z8801). ), 37 (opening 250 μm), 38 (opening 150 μm), 61 (dish)), and each sieve was sieved for 10 minutes with a vibration force MAX using a sieve tester TSK B-1. It can be measured by measuring the mass of the particles remaining in the sieve and determining the particle diameter when the mass becomes 50%.

<Manufacturing method by solution polymerization method>
Hereinafter, as a suitable method for producing the methacrylic resin, for example, the solution polymerization method described in Special No. 2017-125185 can be mentioned.

(Other ingredients)
<Other resins>
The methacrylic resin composition of the present embodiment may be contained in combination with other known resins as long as it can exhibit the characteristics required for the methacrylic resin composition of the present embodiment.
Examples of other resins include thermoplastic resins, and the thermoplastic resins are not limited to the following, but for example, rubbery polymers such as acrylic rubber, polyethylene resins, polypropylene resins, and the like. Polystyrene resin, Syndiotactec Polystyrene resin, Polycarbonate resin, ABS resin, Acrylic resin, AS resin, BAAS resin, MBS resin, AAS resin, Biodegradable resin, Polycarbonate-ABS resin alloy, Polyalkylene allylate Examples thereof include based resins (polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, etc.), polyamide resin, polyphenylene ether resin, polyphenylene sulfide resin, phenol resin and the like.
In particular, AS resin and BAAS resin are preferable from the viewpoint of improving fluidity, acrylic rubber polymer, 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. It is preferable from the viewpoint of.
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 used in the present embodiment, when the above-mentioned methacrylic resin and the other resin are combined, the effect of the present invention may be exhibited as long as the effect of the present invention can be exhibited, but the effect of imparting characteristics is taken into 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 preferable, more preferably 85% by mass or less, still more preferably 80% by mass or less, and even more preferably 75% by mass or less.
When a resin other than the acrylic resin is blended as the other resin, it is preferably 50% by mass or less, more preferably 50% by mass or less, based on 100% by mass of the total amount of the above-mentioned methacrylic resin and the other resin. Is 45% by mass, more preferably 40% by mass or less, even more 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 other resins are blended, 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>
In the methacrylic resin composition used in this embodiment, other additives may be optionally added. The additive is not particularly limited as long as the effect of the present invention can be exhibited, and may be appropriately selected depending on the intended purpose.
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, naphthen-based process oil, aromatic-based). Process oils, paraffins, organic polysiloxanes, mineral oils); flame retardants (eg, organic phosphorus compounds, red phosphorus, phosphorus such as inorganic phosphates, halogens, silicas, silicones, etc.); flame retardants (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 and dihydrazide adipate, phenolic resins such as phenol novolac resin and cresol novolac resin, polymercaptan such as liquid polymercaptan and polysulfide, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, methylcyclohexenetetracarboxylic acid 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, , Polypolymer 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; Demolding 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). Amids, etc.); Impact-imparting agent; Sliding improver (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. Strengthening agent; Flow conditioner; Dyes (nitroso dye, nitro dye, azo dye, stillben azo dye, ketoimine dye, triphenylmethane dye, xanthene 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 and other dyes); sensitizers; 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, kinaku Organic pigments such as lidone pigments, perylene pigments, anthraquinone pigments, perinone pigments, condensed polycyclic pigments such as dioxazine violet, flaky 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.); Antifoaming agent, etc.); Coupling agent; Light-diffusing fine particles; Anti-rust agent; Antibacterial / antifungal agent; Antifouling agent; Conductive polymer, etc.

<< Light Stabilizer >>
A light stabilizer may be added to the methacrylic resin composition used in the present embodiment in order to improve the weather resistance.
As the light stabilizer, a hindered amine-based light stabilizer (HALS) can be preferably added.
Suitable light stabilizers are, but are not limited to, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-octyloxy-2,). 2,6,6 tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 2- (3,5-di-tert-butyl-4-hydroxy) Benzyl) -2-n-butylmalate bis (1,2,2,6,6-pentamethyl-4-piperidyl), tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2 , 3,4-Butanetetracarboxylate, 1,2,2,6,6-pentamethyl-4-piperidyl / tridecyl-1,2,3,4-butanetetracarboxylate, {1,2,2,6 6-Pentamethyl-4-piperidyl / β, β, β', β'-tetramethyl-3,9- [2,4,5,10-tetraoxaspiro (5,5) undecane] diethyl} -1,2 , 3,4 Butanetetracarboxylate, and the like.
In addition, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, N, N'-bis (3-aminopropyl) ethylenediamine-2, 4-Bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate, poly [[6-[( 1,1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidinyl) imino]], Poly [{6- (1,1,3-trimethylpentyl) amino-1,3,5-triazine-2,4-diyl} {(N-methyl-2,2,6,6-tetramethyl-piperidyl) Imino} octamethylene {(N-methyl-2,2,6,6-tetramethyl-piperidyl) imino}], poly [(6-morpholino-S-triazine-2,4-di) [1,2,2 , 6,6-Pentamethyl-4-piperidyl] imino] -hexamethylene [(1,2,2,6,6-pentamethyl-4-piperidyl) imino]], poly [{6- (1,1,3,3 3-Tetramethylbutyl) Amino-1,3,5-triazin-2,4-diyl} {(2,2,6,6-tetramethyl-piperidyl) imino} hexamethylene {(2,2,6,6) -Tetramethyl-piperidyl) imino}], bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl ] Butylmalonate, a mixture of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2) 2,6,6-tetramethyl-4-piperidyl) sebacate, N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N'-diformylhexamethylenediamine, di Butylamine 1,3,5-triazine and N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-) Polycondensate of tetramethyl-4-piperidyl) butylamine, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {2 2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2) , 6,6-tetramethyl-4-piperidyl) imino}]], tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butane 2,2,6,6-tetramethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate, 1,2,2,6,6-pentamethyl-4-piperidyl and β, β, β With', β'-tetramethyl-2,4,8,10-tetraoxaspiro [5.5] undecane-3,9-diethanol reaction, 2,2,6,6-tetramethyl-4-piperidiol β, β, β', β'-tetramethyl-2,4,8,10-tetraoxaspiro [5.5] Undecane-3,9-diethanol reaction product, bis (1-undecanoxy-2,2,2) 6,6-Tetramethylpiperidin-4-yl) carbonate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate and the like. ..
Among them, from the viewpoint of thermal stability of the light stabilizer, bis (1,2,2,6,6-pentamethyl-4-piperidyl) containing three or more ring structures [[3,5-bis (1,1) -Dimethylethyl) -4-hydroxyphenyl] methyl] butylmalonate, dibutylamine 1,3,5-triazine and N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl-1, Polycondensate of 6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{6- (1,1,3,3-tetramethylbutyl) amino- 1,3,5-triazin-2,4-diyl} {2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) ) Imino}], 1,2,2,6,6-pentamethyl-4-piperidol and β, β, β', β'-tetramethyl-2,4,8,10-tetraoxaspiro [5.5] Undecane-3,9-diethanol reactant, 2,2,6,6-tetramethyl-4-piperidiol and β, β, β', β'-tetramethyl-2,4,8,10-tetraoxaspiro [5.5] Undecane-3,9-diethanol and the like are preferably used.

<< Heat Stabilizer >>
The heat stabilizer is not limited to the following, and includes, for example, (a) hindered phenol-based antioxidant, (b-1) phosphorus-based antioxidant, and (b-2) sulfur-based antioxidant. Examples include agents.
The methacrylic resin composition used in this 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-walled 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, (b-1) phosphorus-based antioxidant. And (b-2) at least one selected from sulfur-based antioxidants and (a) hindered phenol-based antioxidants are preferably used in combination.
These antioxidants may be used alone or in combination of two or more.

As the thermal stabilizer, from the viewpoint of further excellent thermal stability in the air, a binary system using (a) a hindered phenol-based antioxidant and (b-2) a sulfur-based antioxidant, or ( a) A dual system using a hindered phenolic antioxidant and (b-1) phosphorus-based antioxidant is preferable, and (a) hinder is particularly excellent in thermal stability in the air over a short period and a long period of time. A ternary system using three types of a dophenol-based antioxidant, a (b-1) phosphorus-based antioxidant, and a (b-2) sulfur-based antioxidant is more preferable.

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 (a) hindered phenolic antioxidant as the heat stabilizer, a commercially available phenolic antioxidant may be used, and such a commercially available phenolic antioxidant is limited to the following. Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by BASF), Irganox 1076 (manufactured by BASF), for example. 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) -trione, manufactured by BASF), Irganox 3125 (Irganox 3125, manufactured by BASF), Adecastab AO-60 (pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 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] Undecane (manufactured by ADEKA), Sumilizer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (manufactured by Sumilizer GA-80, manufactured by Sumitomo Chemical) , Sumilyzer GS (Sumilizer GS: 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, manufactured by Sumitomo Chemical Co., Ltd. GM (Sumilizer GM: 2-tert-butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), vitamin E (manufactured by Esai), etc. Can be mentioned.
Among these commercially available hindered 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 (b-1) 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 '-Diylbisphosphonite, 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-phosphonite, 4- [3-[(2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepine) -6-yloxy ] Proxyl] -2-methyl-6-tert-butylphenol and the like.

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, manufactured by BASF), ADEKA STAB 329K (ADK STAB-329K, manufactured by ADEKA), ADEKA STAB PEP-36 (ADK STAB PEP-36, manufactured by ADEKA), ADEKA STAB PEP-36A (made by ADEKA) ADK STAB PEP-36A, made by ADEKA), ADEKA STAB PEP-8 (ADK STAB PEP-8, made by ADEKA), ADEKA STAB HP-10 (ADK STAB HP-10, ADEKA), ADEKA TAB 2112 (ADK STAB 2112, ADEKA) ), ADEKA STAB 1178 (ADKA STAB 1178, ADEKA), ADEKA STAB 1500 (ADK STAB 1500, ADEKA) Sandstab P-EPQ (Clariant), Weston 618 (Weston 618, GE), Weston 619G (Weston) ), Ultranox 626 (manufactured by ULtranox 626, GE), Sumilyzer 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. -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 (b-2) sulfur-based antioxidant as the heat stabilizer is not limited to the following, but is, for example, 2,4-bis (dodecylthiomethyl) -6-methylphenol (irga). Knox 1726, manufactured by BASF), Irganox 1520L, manufactured by BASF), 2,2-bis {[3- (dodecylthio) -1-oxoporopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (ADEKA STUB AO-412S, manufactured by ADEKA), 2,2-bis {[3- (dodecylthio) -1-oxoporopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (Cheminox PLS, Chemipro Chemicals) (Manufactured by Co., Ltd.), Di (tridecyl) 3,3'-thiodipropionate (AO-503, manufactured by ADEKA Corporation) and the like.
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 further more preferably, with respect to 100 parts by mass of the based resin. It is preferably 0.01 to 0.8 parts by mass, and particularly preferably 0.01 to 0.5 parts by mass.
Further, from the viewpoint of suppressing the thermal decomposition of the methacrylic resin, suppressing the deterioration of the color tone of the obtained molded product, suppressing the volatilization of the heat stabilizer, and suppressing the generation of silver streaks during the molding process, the methacryl is described. (A) 0.01 to 2 parts by mass (preferably 0.02 to 1 part by mass) of a hindered phenol-based antioxidant is contained in 100 parts by mass of the based resin, and (b-1) phosphorus-based antioxidant is contained. It is preferable that the agent and the (b-2) sulfur-based antioxidant are contained in a total of 0.01 to 2 parts by mass (preferably 0.01 to 1 part by mass). Further, from the same viewpoint, (a) 0.01 to 2 parts by mass (preferably 0.02 to 1 part by mass) of the hindered phenol-based antioxidant is contained in 100 parts by mass of the methacrylic resin. It is preferable to contain (b-1) a phosphorus-based antioxidant and / or (b-2) a sulfur-based antioxidant in a total of 0.01 to 2 parts by mass (preferably 0.01 to 1 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.
Commercially available products are not limited to the following, but for example, Riken Vitamin's Rikemar series, Poem series, Rikestar series, Rikemaster series, Kao's Exel series, Leodor series, and Exepearl series. , Coconard series, more specifically, Rikemar S-100, Rikemar H-100, Poem V-100, Rikemar B-100, Rikemar HC-100, Rikemar S-200, Poem B-100, Rikestar EW. -200, Riquester EW-400, Exel S-95, Leodor MS-50 and the like.

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 sebacic acid amide; unsaturated fatty acids such as ethylene bisoleic acid amides, hexamethylene bisoleic acid amides, N, N'-diorail adipic acid amides, N, N'-diorail sebacic 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 are not limited to the following, but for example, Diamid series (manufactured by Nihon Kasei), Amide series (manufactured by Nihon Kasei), Nikka amide series (manufactured by Nihon Kasei), Methylol amide series, Examples include bisamide series, slipax series (manufactured by Nihon Kasei), Kao wax series (manufactured by Kao), fatty acid amide series (manufactured by Kao), ethylene bisstearic acid amides (manufactured by Dainichi Kagaku Kogyo), etc. ..

The fatty acid metal salt refers to a metal salt of a higher fatty acid, and is not limited to, for example, lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinolate, strontium stearate, stearic acid. Barium, barium laurate, barium ricinolate, zinc stearate, zinc laurate, zinc ricinolate, zinc 2-ethylhexoneate, lead stearate, lead dibasic stearate, lead naphthenate, calcium 12-hydroxystearate, 12 − Lithium hydroxystearate and the like can be mentioned, and among them, calcium stearate, magnesium stearate, and zinc stearate are particularly preferable because the obtained methacrylic resin composition has excellent processability and extremely excellent transparency. preferable.
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 lubricant may be used alone or in combination of two or more.
As the lubricant used, it is preferable that the decomposition start temperature is 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 for example, a benzotriazole compound, a benzotriazine compound, a benzoate compound, a benzophenone compound, an oxybenzophenone compound, a phenol compound, an oxazole compound, and the like. Examples thereof include malonate-based compounds, cyanoacrylate-based compounds, lactone-based compounds, salicylic acid ester-based compounds, and benzoxadinone-based compounds.

The benzotriazole-based compound is not limited to the following, and is, for example, 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-yl] -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, reaction of methyl 3- (3- (2H-benzotriazole-2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 Product, 2- (2H-benzotriazole-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2-[ 2-Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 3- (2H-benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4 -Hydroxy-C7-9 side chains and linear alkyl esters can be mentioned.

The benzotriazine-based compound is not limited to the following, but is, for example, 2-mono (hydroxyphenyl) -1,3,5-triazine compound, 2,4-bis (hydroxyphenyl) -1,3. Examples thereof include 5-triazine compound and 2,4,6-tris (hydroxyphenyl) -1,3,5-triazine compound, specifically 2,4-diphenyl-6- (2-hydroxy-4-methoxy). Phenyl) -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-Hydrazine-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-octyloxyphenyl) -1,3,5-triazine, 2,4,5-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-Hydrazine-4-ethoxycarbonylethyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4- (1- (2-ethoxyhexyloxy) -1-oxo) Propanan-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-methi) Ru-4-methoxycarbonylpropyloxyphenyl) -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 so on.

Among these, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-] is highly compatible with amorphous thermoplastic resins, especially acrylic resins, and has excellent absorption characteristics. 4- (3-alkyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton ("alkyloxy" means long-chain alkyloxy groups such as octyloxy, nonyloxy, decyloxy) An ultraviolet absorber having the above is preferred.

As the ultraviolet absorber, benzotriazole-based compounds and benzotriazine-based compounds are particularly preferable from the viewpoint of compatibility with resins and volatilization during heating.
Only one kind of these ultraviolet absorbers may be used alone, or two or more kinds thereof may be used in combination.

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 mass reduction 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, 5 parts by mass or less is preferable, more preferably 3 parts by mass or less, and further preferably 2.5 parts by mass with respect to 100 parts by mass of the methacrylic resin. Below, it is even more preferably 2 parts by mass or less, even more preferably 1.8 parts by mass or less, and 0.01 parts by mass or more from the viewpoint of exerting the effect of blending.

(Characteristics of methacrylic resin composition)
Hereinafter, the characteristics of the methacrylic resin composition will be described.

<Weight average molecular weight, molecular weight distribution>
The weight average molecular weight (Mw) of the methacrylic resin composition used in the present embodiment is 65,000 to 300,000 from the viewpoint of obtaining a methacrylic resin composition having further excellent mechanical strength, solvent resistance, and fluidity. Is.
By setting the weight average molecular weight of the methacrylic resin composition in the above range, the methacrylic resin composition is 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 200,000 or less, still more preferably 15 from the viewpoint of ensuring fluidity during molding, reducing strain during molding, and imparting long optical path transmittance. It is 10,000 or less, more preferably 130,000 or less, and even more preferably 120,000 or less.
The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the methacrylic resin composition shall be 1.5 to 5 from the viewpoint of the balance between fluidity, mechanical strength, and solvent resistance. Is preferable. 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 1.6 to 2.5.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the methacrylic resin composition 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 sample of the methacrylic resin composition to be measured can be obtained from the obtained calibration curve.
Specifically, it can be measured by the method described in Examples described later.

<Heat resistance>
As an index of heat resistance, the VICAT softening temperature can be used.
The Vicat softening temperature of the methacrylic resin composition used in the present embodiment is preferably 113 ° C. or higher, more preferably 115 ° C. or higher, from the viewpoint of heat resistance during actual use.
The Vicat softening temperature can be measured in accordance with ISO306 B50, and specifically, it can be measured by the method described in Examples described later.

<Transparency>
The total light transmittance can be used as an index of transparency.
The total light transmittance of the methacrylic resin composition used in the present embodiment may be appropriately optimized according to the application, but when it is used in an application requiring transparency, it has a thickness of 2 m from the viewpoint of visibility. The total light transmittance in the above is preferably 80% or more. It is more preferably 85% or more, still more preferably 88% or more, and even more 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 can be measured by the method described in Examples described later.

<Rate of change in YI value during stay>
When the resin composition is subjected to a heat history processing such as molding, it may be exposed to a high temperature for a long time due to troubles. At that time, it may turn yellow due to the heat history.
According to the methacrylic resin composition of the present embodiment, the degree of change (ΔYI) between YI when receiving a short heat history and YI when receiving a heat history during long-term holding is suppressed. can do.
For example, the methacrylic resin composition of the present embodiment is subjected to an injection molding machine (EC-100SX, manufactured by Toshiba Machine Co., Ltd.) under the conditions of a molding temperature of 280 ° C. and a mold temperature of 60 ° C., with a thickness of 3 mm and a width of 20 mm. × When preparing a test piece with a length of 220 mm, the injection molding cycle time (injection time + cooling time) was set to (c) 45 seconds, which is a normal cycle, and (d) 270 seconds, assuming retention in the molding machine. In this case, using the test pieces from the 11th shot to the 15th shot after the molding became stable, the test piece obtained in the cycle time (c) and the test piece obtained in (d), 5 pieces each. It can be estimated by measuring the 220 mm long optical path YI value for each.
Obtain the average value of the YI values of the five test pieces in (c) and the average value of the YI values of the five test pieces in (d), calculate the rate of change of the YI value from the following formula, and use it as an evaluation index. Can be.
Rate of change of YI value = [mean value of YI value in (d)-mean value of YI value in (c)] / average value of YI value in (c) × 100 (%)
The degree of change (ΔYI) of the YI (220 mm) is preferably 20% or less, more preferably 18% or less, still more preferably 15% or less, still more preferably 13% or less, still more preferably 10%. It is as follows.
As a means for achieving the above degree of change (ΔYI), the content of the styrene monomer unit is set to a predetermined amount or less, and the compound (D) represented by the general formula (1) or (2) described later is used. A small amount thereof should be contained, the ratio of the component (D) to the content of the structural unit (B) having a ring structure in the main chain should be within a specific range, and Mw should be set to a predetermined degree or more. , These may be used alone or in combination.
The YI value can be measured in accordance with JIS K7105 using a color difference meter (manufactured by Tokyo Denshoku Co., Ltd., TC-8600A, light source: 10-C), and will be described in detail later. It can be measured by the method described in the examples.

<Total light transmittance and thickness dependence of ΔYI>
In the methacrylic resin composition of the present embodiment, the attenuation rate of the total light transmittance from the thickness of 3 mm to the thickness of 220 mm represented by the following formula is preferably 40% or less, more preferably 33% or less, and further. It is preferably 15% or less, and even more preferably 11% or less.
Attenuation rate of total light transmittance (%) = 100 × (Y (3 mm) -Y (220 mm)) / Y (3 mm)
Further, in the methacrylic resin composition of the present embodiment, ΔYI having a thickness of 3 mm to 220 mm represented by the following formula is preferably 40 or less, more preferably 15 or less, still more preferably 5 or less, still more. It is preferably 2 or less.
ΔYI = YI (220mm) -YI (3mm)

<Appearance>
The appearance of the methacrylic resin composition of the present embodiment can be evaluated by, for example, the presence or absence of air bubbles, the presence or absence of streak unevenness, the presence or absence of silver streaks, and the like.
The methacrylic resin composition of the present embodiment is obtained from among 50 test pieces formed by drying the methacrylic resin composition at 80 ° C. for 24 hours and then using an injection molding machine and a measuring mold. The number of test pieces in which silver streaks are found on the surface of the test pieces is preferably 10 or less, more preferably 5 or less, still more preferably 2 or less.
The presence or absence of silver streaks in the methacrylic resin composition can be evaluated by the method described in Examples described later.

<Weather resistance>
The weather resistance of the methacrylic resin composition of the present embodiment can be evaluated by measuring the color difference (ΔE *) of the sample before and after the exposure test.
For example, the methacrylic resin composition of the present embodiment is subjected to a thickness of 3 mm × by an injection molding machine (EC-100SX, manufactured by Toshiba Machine Co., Ltd.) under the conditions of a resin temperature of 280 ° C. and a mold temperature of 70 ° C. A long optical path test piece having a width of 20 mm and a length of 220 mm was prepared, and an exposure test with a total exposure time of 2040 hours was performed using the test piece having a thickness of 3 mm using the method of JIS K7350-4, and before and after the exposure test. The color difference (ΔE *) of can be measured using a color difference meter according to JIS Z8730.
In the methacrylic resin composition of the present embodiment, the color difference (ΔE *) is preferably less than 3, more preferably 2.5 or more and less than 3, and further preferably 2 or less in the above evaluation.
As a means for achieving the above-mentioned degree of change color difference color difference (ΔE *), the content of the styrene monomer unit is set to a predetermined amount or less, and the compound represented by the general formula (1) or (2) described later ( A small amount of D) can be contained, the ratio of the content of the component (D) to the content of the structural unit (B) having a ring structure in the main chain can be set within a specific range, and Mw can be set to a predetermined degree or more. These may be used alone or in combination.
The color difference (ΔE *) can be specifically measured by the method described in Examples described later.

In particular, from the viewpoints of heat resistance, suppression of silver generation during molding, and hue, the amount of the remaining component (A), that is, the methacrylic ester monomer, is 1% by mass or less in the methacrylic resin composition. Is more preferable, 0.7% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.3% by mass or less, still more preferably 0.2% by mass or less.
In particular, the content of the monomer component derived from the component (B) remaining in the methacrylic resin composition is 100% by mass of the methacrylic resin composition from the viewpoint of improving the yellowness and the permeability of the molded piece. When, it is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, still more preferably 0.2% by mass or less, still more preferably 0.15% by mass or less, still more preferably. Is 0.1% by mass or less. Further, it is preferable to keep the amount of residual monomers low, but if an attempt is made to reduce the amount of residual monomers as much as possible, the process may become complicated and the productivity may be affected. Considering the hue and productivity, the content of the remaining component (B) is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, still more preferably 0.011% by mass or more, still more preferably. Is 0.02% by mass or more.
The content of the residual monomer can be evaluated by the method described in Examples described later.

(Manufacturing method of methacrylic resin composition)
The methacrylic resin composition of the present embodiment contains the above-mentioned methacrylic resin, the compound (D) represented by the general formula (1) or (2), and if necessary, other resins, additives and the like. It can be produced by melt-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 from the viewpoint 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 is in the range of 140 to 300 ° C., preferably 180 to 280 ° C. as a guide.
Further, it is preferable that the extruder is provided with a vent port for the purpose of reducing volatile matter.

(Molded body)
The molded product of the present embodiment may contain the above-mentioned methacrylic resin composition of the present embodiment in an amount of 80% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more. It may be composed of a methacrylic resin composition (containing 100% by mass).

The shape of the molded product of the present embodiment may be appropriately determined according to the purpose and application, and is not particularly limited, but a lens for a surveillance camera and a lens cover are preferable.

The thickness of the surveillance camera lens and the lens cover of the present embodiment is 0.01 to 0.01 from the viewpoint of excellent handleability and strength, and from the viewpoint of excellent optical characteristics when the molded body of the present embodiment is used as an optical component. 10 mm is preferable. From the viewpoint of suppressing birefringence, the thickness is preferably 0.02 mm or more, more preferably 0.03 mm or more, further preferably 0.05 mm or more, and even more preferably 8 mm or less. , More preferably 5 mm or less, even more preferably 3 mm or less, still more preferably 2 mm or less.

(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.
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, the 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. The method can also be mentioned as an example of a method for producing a molded product.

Hereinafter, the present embodiment will be described with reference to specific examples and comparative examples, but the present embodiment is not limited to the examples described later.

〔material〕
The raw materials used in Examples and Comparative Examples described later are shown below.

(Monomers constituting methacrylic resin)
<(A) Methacrylate monomer>
<< (A-1) >>
-Methyl methacrylate (MMA): manufactured by Asahi Kasei Corporation (2,4-dimethyl-6-t-butylphenol manufactured by Chugai Trading Co., Ltd. as a polymerization inhibitor (2,4-di-methyl-6-tert-butylphenyl)) 2.5 ppm added)

<(B) Monomer for forming a structural unit having a ring structure in the main chain>
<< (B-1-1) Maleimide-based structural unit >>
-N-Phenylmaleimide (N-PMI): manufactured by Nippon Shokubai Co., Ltd. << (B-1-2) maleimide-based structural unit >>
-N-Cyclohexylmaleimide (N-CMI): Synthesized by the following production method.
A flask equipped with a thermometer, a Dean-Stark apparatus, a dropping funnel, and a stirrer is charged with 6 times the amount of maleic anhydride and maleic anhydride per unit mass, and the temperature is raised to 55 ° C. and stirred to obtain maleic anhydride. A uniform maleic anhydride solution was prepared.
Next, a solution containing an equivalent amount of cyclohexylamine in terms of molar ratio to maleic anhydride and an orthoxylene having the same mass as that of the maleic anhydride solution was added dropwise to this maleic anhydride solution at 55 ° C. under stirring for 30 minutes. A slurry solution of orthoxylen of cyclohexyl maleic anhydride was synthesized.
Next, 200 ppm of copper dibutyldithiocarbamate was added to the above slurry liquid as an acid catalyst with the same mass as orthophosphoric acid as cyclohexylamine, and as a polymerization inhibitor with respect to N-cyclohexylmaleinamide acid, and the mixture was heated and kept at 140 ° C. under stirring. The reaction was carried out for 8 hours while distilling the water produced by the reaction out of the reaction system with a Dean Stark tube. After completion of the reaction, the acid catalyst layer separated into the lower layer was separated and removed from the reaction solution at 140 ° C. Subsequently, the reaction solution was washed twice with 3% by mass sulfuric acid water and twice with ion-exchanged water to remove orthoxylene from the organic layer under reduced pressure of 10 mmHg, and further under reduced pressure of 5 mmHg, the internal temperature was 130 to 150. By performing distillation purification at ° C., a raw material containing white N-cyclohexylmaleimide as a main component was obtained.
<< (B-3) Glutarimide-based structural unit >>
-Methyl methacrylate (MMA): << (A-1) >> described above.
・ Methacrylic acid (MA): Made by Tokyo Chemical Industry Co., Ltd.

<(C) Vinyl-based monomer>
<< (C-1) >>
-Styrene (St): manufactured by Asahi Kasei Corporation << (C-2) >>
・ Methacrylic acid (MA): Made by Tokyo Chemical Industry Co., Ltd.

<(D) compound>
<< (D-1) >>
N-Cyclohexyl-2-hydroxysuccinimide: Needle-shaped crystals of the component (D-1) were obtained by repeating recrystallization purification using the initial distillation at the time of distillation obtained during the production of (B-2).

(Organic solvent)
・ Metaxylene: Made by Mitsui Chemicals, Inc.

(Other)
-N-octylmercaptan (NOM): manufactured by Arkema Co., Ltd., used as a chain transfer agent.
-Perhexa C-75 (EB): manufactured by NOF CORPORATION, with a purity of 75% (containing 25% ethylbenzene), used as a polymerization initiator.
-T-Butylperoxy-2-ethylhexanoate: manufactured by NOF CORPORATION, used as a polymerization initiator.
-Calcium phosphate (calcium phosphate): manufactured by Nippon Chemical Industrial Co., Ltd., used as a suspension agent.
-Calcium carbonate: manufactured by Shiraishi Kogyo Co., Ltd., used as a suspending agent.
-Sodium lauryl sulfate: manufactured by Wako Junyaku Co., Ltd., used as a suspension aid.

<Additives>
<< a-1 >>
-ADEKA STAB AD2112: Made by ADEKA CORPORATION << a-2 >>
-ADEKA STAB AO-80: Made by ADEKA CORPORATION << a-3 >>
・ Chinubin P: 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 produced in the production example described later and the methacrylic resin composition produced in the example was measured with the following devices and conditions.
-Measuring device: Gel Permeation Chromatography (HLC-8320GPC) manufactured by Tosoh Corporation
·Measurement condition:
Column: 1 TSKguardcolum SuperH-H, 2 TSKgel SuperHM-M, and 1 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, flow velocity; 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 in tetrahydrofuran 20 mL Injection amount: 10 μL
Standard sample for calibration curve: The following 10 types of polymethyl methacrylate (PMMA Calibration Kit M-M-10, manufactured by Polymer Laboratories), which have known monodisperse weight peak 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 was measured.
The weight average molecular weight (Mw) of the methacrylic resin and 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. The results are shown in Table 1.

(II. Measurement of the composition of the monomer unit of the polymer and the amount of residual monomer)
<II-1. Measurement of monomer unit composition>
For the obtained methacrylic resin and the obtained methacrylic resin composition, 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.
<II-2. Measurement of residual monomer amount>
The measurement was carried out by the calibration curve method using GC.
More specifically, a part of the obtained methacrylic resin composition was collected and weighed, and then
This sample was dissolved in chloroform to prepare a 0.5% by mass solution, and nonane was added as an internal standard substance.
A capillary column (manufactured by phenomenex, product number: ZB-1) having an inner diameter of 0.32 mm and a length of 30 m was used for FID type gas chromatography (product number: GC2025) manufactured by Shimadzu Corporation.
In the measurement, after holding at 45 ° C. for 5 minutes, the temperature is raised to 110 ° C. at a heating rate of 10 ° C./min, then to 200 ° C. at 30 ° C./min, and further to 240 ° C./10 ° C./min. The temperature was raised in minutes, then raised to 300 ° C. at 50 ° C./min, and held at 300 ° C. for 10 minutes.

(III. Measurement of physical properties)
Hereinafter, the evaluation method of the methacrylic resin and the methacrylic resin composition will be described.

<III-1. Heat resistance; Measurement of VICAT softening temperature>
Using a 4 mm thick test piece molded using the resin pellets obtained in Examples and Comparative Examples described later, the VICAT softening temperature (° C.) was measured in accordance with ISO 306 B50, and used as an index for heat resistance evaluation. did.

<III-2. Transparency (optical characteristics); Measurement of total light transmittance>
Using the resin pellets obtained in Examples and Comparative Examples described later, a test piece having a thickness of 3 mm was formed by injection molding, and the total light transmittance was measured in accordance with JIS K7361-1 standard. It is preferable that the total light transmittance is 90% or more, which is the same level as a general commercially available acrylic resin (PMMA).

<III-3. Degree of change of YI value (ΔYI)
The methacrylic resin and the resin composition obtained in Examples and Comparative Examples described later are subjected to an injection molding machine (EC-100SX, manufactured by Toshiba Machine Co., Ltd.) under the conditions of a molding temperature of 280 ° C. and a mold temperature of 60 ° C. A test piece having a thickness of 3 mm, a width of 20 mm, and a length of 220 mm was prepared.
The injection molding cycle time (injection time + cooling time) was (c) 45 seconds or (d) 270 seconds.
Using the test pieces from the 11th shot to the 15th shot after the molding became stable, the 220 mm long optical path YI value of each of the five test pieces obtained in the cycle times (c) and (d) was measured. It was.
Then, the average value of the YI values of the five test pieces of (c) and the average value of the YI values of the five test pieces of (d) were obtained, and the average value of the YI values of [(d)-(c). The degree of change (ΔYI) of the YI value in the 220 mm long optical path was calculated from the average value of the YI values of] / (c) × 100 (%).
The YI value was measured in accordance with JIS K7105 using a color difference meter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd., light source: 10-C).
<Long-term retention evaluation result>
If the degree of change of the YI value is 10% or less, it is "◎", if it is more than 10% and 13% or less, it is "○", if it is 20% or less, it is "△", and if it is more than 20%, it is "×". Was evaluated as.

<Total light transmittance and thickness dependence of ΔYI>
The total light transmittance Y (3 mm) at a thickness of 3 mm and the total light transmittance Y (220 mm) at a thickness of 220 mm were measured by the same measurement method as in (III-2) above, and 100 × (Y (3 mm) −. Y (220 mm)) / Y (3 mm) was defined as the attenuation rate (%) of the total light transmittance.
Further, YI (3 mm) at a thickness of 3 mm and YI (220 mm) at a thickness of 220 mm are measured by the same measurement method as in (III-3) above, and the difference (YI (220 mm) -YI (3 mm)) ΔYI was calculated.

<III-4. With or without Silver Streak>
The methacrylic resin compositions obtained in Examples and Comparative Examples described later were dried at 80 ° C. for 24 hours, and then the injection molding machine and the measuring die described below were subjected to silver streak using the following molding conditions. The presence or absence of resin was evaluated.
Specifically, the resin was injected into the central portion of the mold surface under the following conditions, and 40 seconds after the completion of the injection, a spiral molded product was taken out, and the presence or absence of silver streaks was evaluated. After switching the resin, 20 shots were discarded, and 50 shots from the 21st shot to the 70th shot were used for evaluation.
-Injection molding machine: EC-100SX (manufactured by Toshiba Machine Co., Ltd.)
-Measurement mold: A mold in which a groove with a depth of 2 mm and a width of 12.7 mm is dug from the center of the surface in an Archimedes spiral shape on the surface of the mold.-Molding conditions Resin temperature: 290 ° C.
Mold temperature: 70 ° C
Maximum injection pressure: 75 MPa
Injection time: 20 sec
・ Evaluation of the presence or absence of silver streaks ◎: 2 or less samples with silver streaks out of 50 ○: 5 or less samples with silver streaks out of 50 △: silver out of 50 10 or less samples with streaks ×: More than 10 samples with silver streaks out of 50

<III-5. Evaluation of releasability ＞
After the methacrylic resin compositions obtained in Examples and Comparative Examples described later were dried at 80 ° C. for 24 hours, the injection molding machine and the measuring die described below were released from the mold using the following molding conditions. Sexuality was evaluated Specifically, after switching the resin, 15 shots were discarded, and 30 shots from the 16th shot to the 45th shot were used for the evaluation.
Injection molding machine: EC-100SX (manufactured by Toshiba Machine Co., Ltd.)
Measuring mold: Thickness 3 mm x Width 20 mm x Length 220 mm Long optical path test piece mold Resin temperature: 280 ° C
Mold temperature: 70 ° C
Releaseability evaluation ◎: 1 or less samples with poor mold release out of 30 ○: 3 or less samples with poor mold release out of 30 △: 30 with poor mold release 7 or less samples were seen ×: Of 30 samples, more than 10 samples were found to have poor mold release

<III-6. Evaluation of weather resistance (moisture and heat resistance), measurement of weather resistance (color difference (ΔE *))>
As an index for weather resistance evaluation, the color difference (ΔE *) of the sample before and after the exposure test was measured.
An exposure test was carried out using the test piece having a thickness of 3 mm formed in (III-5) above and using the method of JIS K7350-4. The exposure conditions were as follows: black panel temperature setting was 63 ± 3 ° C, water spray time setting was (18 ± 0.5) minutes, spray stop time setting was (102 ± 0.5) minutes, and total exposure time was 2040. It was time.
The setting of the sample piece was performed so that the 20 mm × 220 mm surface of the above-mentioned 3 mm thick test piece was the exposed surface.
The test piece after exposure was washed with water, and then the object color was measured.
The value of ΔE * was used as the color difference. The measurement was carried out according to JIS Z8730 on the exposed surface of the flat plate-shaped evaluation sample using a color difference meter. Specifically, the color difference ΔE * of the transmitted light in the thickness direction from the exposed surface was measured.
<Weather resistance evaluation>
In the above evaluation, those with ΔE * of 2 or less are “◎”, those with ΔE * exceeding 2 and less than 2.5 are “○”, those with ΔE * of 2.5 or more and less than 3 are “△”, and those with “3” or more. Was evaluated as "x".

<IV. Comprehensive evaluation ＞
In the above evaluation, the weather resistance and the degree of change in YI difference (ΔYI) between long-term residence molding and normal molding are particularly small, and those judged to be most suitable for optical component applications and in-vehicle component applications are “5”, and optical components. "4" is judged to be suitable for applications and in-vehicle member applications, "3" is judged to be suitable for applications where color tone change during heating retention is not a concern, and weather resistance for vehicle interior applications, etc. Those judged to be suitable for applications that do not place importance on are marked with "2", and those judged to be unsuitable for in-vehicle use and optical component use are designated as "1".

Hereinafter, production examples of methacrylic resins will be described.

[Manufacturing Example 1]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were put into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was added to a 60 L reactor having a stirrer equipped with three swept blades to raise the temperature to 75 ° C., a mixture (a) was added, and then 95 parts by mass of methyl methacrylate (A) was added. , Cyclohexyl maleimide (B-2) by 5 parts by mass, chain transfer agent n-octyl mercaptan by 0.295 parts by mass, and polymerization initiator t-butylperoxy-2-ethylhexanoate by 0.25 parts by mass. 22 kg of the premixed monomer mixture was added.
Suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 120 minutes after the raw material mixture was added.
Then, the temperature was raised to 97 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, 20% by mass sulfuric acid was added to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove agglomerates, water was filtered off, and the obtained slurry was dehydrated to obtain a beaded polymer, and the obtained beaded polymer was obtained. After washing with water, the mixture was dehydrated in the same manner as described above, and further washed with ion-exchanged water and dehydrated repeatedly to obtain polymer particles. The average particle size was 0.29 mm.
Using a 3-vent φ37 mm extruder with the obtained polymer particles set to a cylinder temperature of 270 ° C near the die, a cylinder temperature of the kneading section of 260 ° C, and a temperature of 230 ° C from the resin charging to the kneading section, the resin charging section While adding purified water in an amount of 4% by mass of the amount of resin between the kneading section and the kneading part, devolatile treatment was performed at 200 rpm at 12 kg / hour in terms of resin amount to obtain resin pellets.
The weight average molecular weight of the obtained resin pellets was 100,000, and the resin composition determined by NMR was MMA unit: 95% by mass and CMI unit: 5% by mass.

[Manufacturing Example 2]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were put into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was added to a 60 L reactor having a stirrer equipped with three swept blades to raise the temperature to 75 ° C., a mixed solution (a) was added, and then 90 parts by mass of methyl methacrylate (A) was added. , Cyclohexyl maleimide (B-2) by 5 parts by mass, styrene by 5 parts by mass, chain transfer agent n-octyl mercaptan by 0.24 parts by mass, polymerization initiator t-butylperoxy-2-ethylhexanoate by 0 parts. .20 parts by mass, 22 kg of the premixed monomer mixture was added.
Suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 120 minutes after the raw material mixture was added.
Then, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, 20% by mass sulfuric acid was added to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove agglomerates, water was filtered off, and the obtained slurry was dehydrated to obtain a beaded polymer, and the obtained beaded polymer was obtained. After washing with water, the mixture was dehydrated in the same manner as described above, and further washed with ion-exchanged water and dehydrated repeatedly to obtain polymer particles.
Using a 3-vent φ37 mm extruder with the obtained polymer particles set to a cylinder temperature of 270 ° C near the die, a cylinder temperature of the kneading section of 260 ° C, and a temperature of 230 ° C from the resin charging to the kneading section, the resin charging section While adding purified water in an amount of 4% by mass of the amount of resin between the kneading section and the kneading part, devolatile treatment was performed at 200 rpm at 12 kg / hour in terms of resin amount to obtain resin pellets.
The weight average molecular weight of the obtained resin pellets was 110,000, and the resin composition determined by NMR was MMA unit: 90% by mass, CMI unit: 5% by mass, and St unit: 5% by mass.

[Manufacturing Example 3]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were put into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was added to a 60 L reactor having a stirrer equipped with three swept blades to raise the temperature to 75 ° C., a mixed solution (a) was added, and then 89 parts by mass of methyl methacrylate (A) was added. , Cyclohexylmaleimide (B-2) by 11 parts by mass, metaxylene by 5 parts by mass, chain transfer agent n-octyl mercaptan by 0.208 parts by mass, polymerization initiator t-butylperoxy-2-ethylhexanoate by 0 parts. .25 parts by mass, 22 kg of the premixed monomer mixture was added.
Suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 120 minutes after the raw material mixture was added.
Then, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, 20% by mass sulfuric acid was added to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove agglomerates, water was filtered off, and the obtained slurry was dehydrated to obtain a beaded polymer, and the obtained beaded polymer was obtained. After washing with water, the mixture was dehydrated in the same manner as described above, and further washed with ion-exchanged water and dehydrated repeatedly to obtain polymer particles. The average particle size was 0.29 mm.
Using a 3-vent φ37 mm extruder with the obtained polymer particles set to a cylinder temperature of 270 ° C near the die, a cylinder temperature of the kneading section of 260 ° C, and a temperature of 230 ° C from the resin charging to the kneading section, the resin charging section While adding purified water in an amount of 4% by mass of the amount of resin between the kneading section and the kneading part, devolatile treatment was performed at 200 rpm at 12 kg / hour in terms of resin amount to obtain resin pellets.
The weight average molecular weight of the obtained resin pellets was 130,000, and the resin composition determined by NMR was MMA unit: 90% by mass and CMI unit: 10% by mass.

[Manufacturing Example 4]
470 kg of methyl methacrylate (MMA), 39 kg of N-phenylmaleimide (B-1), 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. 41 kg of N-cyclohexylmaleimide (B-2), 450.0 kg of metaxylene, and n-octyl mercaptan were charged in an amount of 1200 mass ppm based on 100 parts by mass of the total amount of all the monomers 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 0.23 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 (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 0.41 kg / hour (4) 2.0 to 3.0 hours: Feed rate 0.36 kg / hour (5) 3.0 to 4.0 hours: Feed rate 0.14 kg / hour (6) 4. 0 to 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 2 hours, 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. The polymerization conversion rate of the obtained polymerization solution was measured and found to be MMA unit: 94.1% by mass, PMI unit: 95.5% by mass, and CMI unit: 93.2% by mass. As a whole, the polymerization conversion rate was 93%.
This polymerization solution was supplied to a tubular heat exchanger preheated to 170 ° C. and a concentrator consisting of a vaporization tank, and the concentration of the polymer contained in the solution was increased to 70% by mass.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² to carry out volatilization. At this time, the temperature inside the apparatus was 275 ° C., the supply amount was 25 L / hour, the rotation speed was 300 rpm, and the degree of vacuum was 25 Torr. The polymer after volatilization was boosted by a gear pump, extruded from the strand die, water-cooled, cut, and resin pellets. Got
The weight average molecular weight of the obtained resin pellets was 120,000, and the resin composition determined by NMR was MMA unit: 86% by mass, PMI unit: 7% by mass, and CMI unit: 7% by mass.

[Manufacturing Example 5]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were put into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was added to a 60 L reactor having a stirrer equipped with three swept blades to raise the temperature to 75 ° C., a mixture (a) was added, and then 95 parts by mass of methyl methacrylate (A) was added. , Cyclohexyl maleimide (B-2) by 5 parts by mass, chain transfer agent n-octyl mercaptan by 0.389 parts by mass, polymerization initiator t-butylperoxy-2-ethylhexanoate by 0.25 parts by mass in advance. 22 kg of the mixed monomer mixture was added.
Suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 120 minutes after the raw material mixture was added.
Then, the temperature was raised to 97 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, 20% by mass sulfuric acid was added to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove agglomerates, water was filtered off, and the obtained slurry was dehydrated to obtain a beaded polymer, and the obtained beaded polymer was obtained. After washing with water, the mixture was dehydrated in the same manner as described above, and further washed with ion-exchanged water and dehydrated repeatedly to obtain polymer particles. The average particle size was 0.29 mm.
The obtained polymer particles were subjected to a resin charging section using a 3-vent φ37 mm extruder in which the cylinder temperature of the portion close to the die was set to 250 ° C, the cylinder temperature of the kneading section was set to 240 ° C, and the temperature from the resin charging to the kneading section was set to 220 ° C. While adding 3% by mass of purified water to the kneading section, a volatilization treatment was performed at 200 rpm at 10 kg / hour in terms of resin amount to obtain resin pellets.
The weight average molecular weight of the obtained resin pellets was 60,000, and the resin composition determined by NMR was MMA unit: 95% by mass and CMI unit: 5% by mass.

[Manufacturing Example 6]
69.1 kg of methyl methacrylate (MMA), 5.32 kg of styrene (St), 9.57 kg in a 200 L reaction kettle equipped with a stirrer equipped with paddle blades, a temperature sensor, a cooling tube, and a nitrogen introduction tube. Methacrylic acid (MAA), 56.0 kg of metaxylene, and 0.105 kg of n-octyl mercaptan were charged to prepare a raw material solution. The temperature was raised to 117 ° C. with stirring while passing nitrogen through it.
Separately, an initiator feed solution A in which 0.029 kg of perhexa 25B and 0.10 kg of metaxylene was mixed, and an initiator feed solution B in which 0.0098 kg of perhexa 25B and 0.10 kg of metaxylene were mixed were prepared.
When the temperature of the raw material solution reached 117 ° C., the initiator feed solution A was fed for 10 minutes at a feed rate of 0.774 kg / hour and reacted for 2 hours. Then, the initiator feed solution B was fed for 10 minutes at a feed rate of 0.110 kg / hour, the reaction was continued for another 10 hours, and the polymerization reaction was carried out for a total of 12 hours and 20 minutes to complete the reaction.
The obtained polymerization solution was supplied to a high-temperature vacuum chamber set at 280 ° C. to remove unreacted substances and a solvent to produce a 6-membered phosphoric acid anhydride.
As a result of composition analysis of this produced copolymer by NMR, MMA unit: 78% by mass, St unit: 7% by mass, MAA unit: 3% by mass, and 6-membered cyclic anhydride unit: 12% by mass.
0.5 kg of the copolymer pellet thus obtained was charged into an autoclave having an internal volume of 5 liters, and then 3.0 kg of N, N-dimethylformamide was added and stirred to dissolve. 28% ammonia water containing 2 equivalents of ammonia was charged with respect to the unit amount of 6-membered phosphoric anhydride, and reacted at 150 ° C. for 2 hours.
The reaction solution was withdrawn and put into n-hexane to precipitate a polymer. The polymer was further treated in a 10 torr volatilizer at 250 ° C. for 2 hours.
The finally obtained copolymer was slightly yellow and transparent, and the composition was determined by elemental analysis of nitrogen content, NMR, and IR. MMA unit: 78% by mass, St unit: 7% by mass, MAA unit: 3 Mass%, glutarimide-based structural unit: 12 mass%. The weight average molecular weight of the copolymer was 130,000.
The above operation was repeated to prepare pellets necessary for evaluation.

Examples and comparative examples of the methacrylic resin composition will be described below.

[Example 1]
With respect to 100 parts by mass of the resin obtained in Production Example 1 described above, 0.04 parts by mass of (D-1), 0.03 parts by mass of tinubin P, Adecastab AD2112: 0.05 parts by mass, and Adecastab AO-80. : 0.1 parts by mass blended by hand blending, with vents (3 places) Φ26mm twin shaft extruder TEM-26SS (L / D = 48, using 4-hole die, die set temperature 250) manufactured by Toshiba Machine Co., Ltd. Melt kneading was performed at a discharge rate of 12 kg / hour, a water bath temperature of 60 ° C. (water contact distance of about 20 cm), and a rotation speed of 180 rpm at the outlet side, hopper horizontal barrel set temperature 220 ° C. A pellet-shaped methacrylic resin composition was produced.
The weight average molecular weight of the obtained methacrylic resin composition was 100,000. The resin composition obtained by NMR for the resin composition was MMA unit: 95% by mass and CMI unit: 5% by mass.
The amount of residual methyl methacrylate was 1200 mass ppm with respect to 100 parts by mass of the methacrylic resin composition, and the amount of residual N-cyclohexylmaleimide was 600 mass ppm with respect to 100 parts by mass of the methacrylic resin composition.
The above physical property evaluation was carried out using the obtained methacrylic resin composition pellets.
The evaluation results are shown in Table 1.
A 4 mm thick test piece was prepared using the resin composition pellet obtained in Example 1, and the Charpy impact strength (without notch) was measured for the 4 mm thick test piece in accordance with the ISO179 / 1eU standard. However, it was 16 kJ / m ² .
In addition, the resin composition pellets obtained in Example 1 were used to prepare a lens and a lens cover having a thickness of 1 mm (minimum) and 4 mm (maximum).

[Examples 2 to 9], [Comparative Examples 1 to 3]
A methacrylic resin composition was produced and evaluated in the same manner as in Example 1 except that the conditions shown in Table 1 were met.
The evaluation results are shown in Table 1.

[Comparative Example 4]
LC1500 was used as the polycarbonate resin.
The evaluation results are shown in Table 1.

As shown in Table 1, when the weight average molecular weight of the methacrylic resin is within a predetermined range, the component (D) is within a predetermined range, and the mass ratio (B) / (D) is within a predetermined range. It was found that it has sufficient optical characteristics for a lens for a surveillance camera and a lens cover, and is excellent in heat resistance, thermal stability, appearance, weather resistance, and molding processability.

The methacrylic resin composition of the present invention and a molded product containing the same have industrial applicability as a lens and a lens cover for a surveillance camera.

Claims (8)

A 220 mm long optical path YI value (220 mm long optical path YI value) measured in accordance with JIS K 7105 for a test piece having a thickness of 3 mm, a width of 20 mm, and a length of 220 mm, which is represented by the following formula (I) and has a cycle time of injection molding of 45 seconds. 220 mm long optical path YI value (220 mm long optical path YI value (270 seconds)) measured in accordance with JIS K 7105 for a test piece prepared with an injection molding cycle time of 270 seconds with respect to 220 mm long optical path YI value (45 seconds)). A lens and a lens cover for a surveillance camera, which comprises a methacrylic resin composition having a degree of change (ΔYI) of 20 or less.
ΔYI = {220 mm long optical path YI value (270 seconds) -220 mm long optical path YI value (45 seconds)} / 220 mm long optical path YI value (45 seconds) ... (I) The lens for a surveillance camera according to claim 1, wherein the color difference ΔE * measured according to JIS Z8730 before and after the 2040 hour exposure test using the method of JIS K7350-4 using a test piece having a thickness of 3 mm is 3 or less. And lens cover. The methacrylic resin composition contains 100 parts by mass of a methacrylic resin containing a structural unit (B) having a ring structure in the main chain, and a compound (D) represented by the following general formula (1) or (2): 0. The lens and lens cover for a surveillance camera according to claim 1 or 2, which contain .001 to 0.2 parts by mass.

(In the formula (1), R represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and aromatic group of R. The group hydrocarbon group may have a sulfur atom, a nitrogen atom, an oxygen atom, and a phosphorus atom on the carbon atom, respectively. R'is an aliphatic hydrocarbon group having 1 to 12 carbon atoms or a carbon number of carbon atoms. Represents 6 to 18 aromatic hydrocarbon groups. Even if the aliphatic hydrocarbon group and the aromatic hydrocarbon group of R'have a sulfur atom, a nitrogen atom, an oxygen atom, and a phosphorus atom on carbon atoms, respectively. Good.)

In the formula (2), R, R', and R'' each independently contain a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 1 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group of R, R'and R'' may have a sulfur atom, a nitrogen atom, an oxygen atom and a phosphorus atom on the carbon atom, respectively. R'and R'' may be combined with each other to form a ring.) Ratio of the content of the structural unit (B) having a ring structure in the main chain in the methacrylic resin composition to the content of the component (D) in the methacrylic resin composition ((B) / (D)) The surveillance camera lens and lens cover according to claim 3, wherein the number is 25 or more and 1000 or less. The lens and lens cover for a surveillance camera according to claim 2 or 3, wherein the weight average molecular weight of the methacrylic resin composition measured by gel permeation chromatography (GPC) is 65,000 to 300,000. The methacrylic acid ester monomer has a methacrylic acid ester monomer unit (A): 50 to 97% by mass, a structural unit (B) having a ring structure in the main chain: 3 to 30% by mass, and a methacrylic acid ester monomer. Other vinyl-based monomer unit (C) copolymerizable with: 0 to 20% by mass, which comprises a methacrylic resin composition satisfying the following conditions (I) and (II). The surveillance camera lens and lens cover according to any one of the above. The structural unit (B) having a ring structure in the main chain 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. The surveillance camera according to any one of claims 3 to 6, which comprises at least one structural unit selected from the group consisting of a ring structural unit (B-4) and an acid anhydride structural unit (B-5). Lens and lens cover. The surveillance camera lens and lens cover according to any one of claims 3 to 7, wherein the thickness is 0.03 to 3 mm.