JP6247373B1 - Methacrylic resin composition, optical film, optical component - Google Patents

Abstract

The present invention relates to a methacrylic resin composition that makes it possible to prepare an optical film having good adhesion to a functional layer laminated at high temperature or high temperature and high humidity, and the methacrylic resin composition It is an object of the present invention to provide an optical film composed of an object and an optical component in which a functional layer is laminated on the optical film. The main chain includes a structural unit (X) having a ring structure, and the (X) structural unit is selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer and a lactone ring structural unit. It contains at least one kind of methacrylic resin and two or more kinds of resins containing a structural unit (Y) having an aromatic group, has a glass transition temperature of more than 120 ° C and not more than 160 ° C, and has a weight average molecular weight ( Mw) satisfies the following relationship: 1.1 ≦ MwUV / MwRI ≦ 2.0, and the amount of methanol soluble component is 100% by mass of the total amount of methanol soluble component and methanol insoluble component. A methacrylic resin composition, an optical film, and an optical component, wherein the content is 5% by mass or less. [Selection figure] None

Description

  The present invention provides a methacrylic resin composition that is capable of preparing an optical film having high heat resistance, excellent optical properties such as birefringence, and having good adhesion to a laminated functional layer, The present invention relates to an optical film composed of a methacrylic resin composition and an optical component in which a functional layer is laminated on the optical film.

  In recent years, methacrylic resins have attracted attention as optical resins for various optical materials, mainly optical films, for example, because they have excellent transparency, surface hardness, etc., and low birefringence, which is an optical property. The market is expanding greatly.

  In particular, it is known that a composition containing a methacrylic resin having a ring structure in the main chain has excellent performance in both heat resistance and optical properties, and a polarizer protective film for an image display device Alternatively, the demand is rapidly expanding in applications such as retardation films.

  Further, for example, in the case of a polarizer protective film used for the outermost layer of a polarizing plate, various types such as a hard coat layer, an antiglare layer (non-glare) layer, an antireflection layer, a light scattering layer, an antistatic layer, and an ultraviolet shielding layer It is often used by forming a functional layer on the film surface.

  For example, as a method of coating a functional layer on the film surface, a corona treatment or a plasma treatment is applied before the functional layer is applied, or an easy adhesion layer called an anchor layer or a primer layer is applied. Then, there is a method in which a liquid containing a composition for imparting a function is coated on the film surface, followed by heating, drying, and curing treatment.

  However, when a film containing an acrylic resin is used as a base film, sufficient adhesion cannot be obtained between the film and the coating layer, and various problems occur at the stage of commercialization of a polarizing plate or the like. There is a current situation that has occurred.

As a method for solving these problems, for example, in Patent Document 1, a method of forming a laminate having a functional layer after forming an intermediate layer containing a specific urethane resin between an acrylic film and the functional layer. Has been proposed.
Patent Document 2 proposes a method using a composition containing an easily adhesive resin and a water-soluble resin as the easily adhesive layer.
And in patent document 3, it has the hard coat layer of two different layers hardened | cured with the active energy ray on the surface of an acrylic film, the 1st layer contains inorganic fine particles, and has the surface roughness of a specific range. An optical film characterized by being a layer has been proposed.
Furthermore, Patent Document 4 has a layer having a component formed by curing an active energy ray-curable compound on the surface of a film made of an acrylic copolymer having a solubility in a selected solvent of 10% or more, An optical film comprising a mixed layer containing both an acrylic copolymer having a specific thickness and a component obtained by curing an active energy ray-curable compound at an interface between the film and the cured layer Proposed.

JP 2012-133314 A JP 2014-048348 A JP 2014-115502 A JP 2014-199320 A

  In these patent documents, in order to improve the adhesion between the base film and the functional layer, a proposal for improving the adhesive layer present between them is made, but the main chain forming the base film is formed. No mention is made regarding improvement of the composition itself containing a methacrylic resin having a ring structure.

  In applications using optical films with functional layers, the usage environment is expected to become increasingly severe in the future, even in use under relatively severe usage environments such as high temperature or high temperature and high humidity. In addition, the proposal of the optical film provided with the functional layer which can maintain favorable adhesiveness is earnestly desired.

  Therefore, the present invention provides a methacrylic resin composition that makes it possible to prepare an optical film having good adhesion to a functional layer laminated at high temperature or high temperature and high humidity, and the methacrylic resin composition And an optical component in which a functional layer is laminated on the optical film.

Here, it examined in detail about the process of providing a functional layer to a substrate film anew.
The composition for providing the easy-adhesion layer and the functional layer used in this step is generally used in a solution state dissolved in an organic solvent or a dispersion state dispersed in water. Therefore, the base film obtained from the composition containing a methacrylic resin having a ring structure in the main chain is strongly affected by the organic solvent used, water, and heating in the drying step. As a result, it is suggested that not only the adhesion with the functional layer is lowered, but also the optical properties and strength of the film are lowered, and further, the warp and deformation of the film after lamination may be caused.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have improved the adhesion between the base film and the functional layer when the functional layer is applied, and in a relatively severe use environment. Therefore, it was considered important to precisely control the composition distribution of the methacrylic resin or resin composition having a ring structure in the main chain to be used. As a result of further intensive studies, it was found that the above problems can be solved by preparing an optical film using a composition containing a methacrylic resin having a specific composition distribution characteristic, and the present invention has been completed. It was.

That is, the present invention is as follows.
[1]
The main unit includes a structural unit (X) having a ring structure, and the (X) structural unit is at least one selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer and a lactone ring structural unit. Including two or more kinds of resins including a methacrylic resin and including a structural unit (Y) having an aromatic group,
The glass transition temperature is over 120 ° C. and below 160 ° C.,
The weight average molecular weight (Mw) in terms of polystyrene measured by GPC satisfies the following relationship:
1.1 ≦ Mw _UV / Mw _RI ≦ 2.0
(In the formula, Mw _RI is a weight average molecular weight obtained using a differential refractive index detector, and Mw _UV means a weight average molecular weight obtained using an ultraviolet-visible absorbance detector at a detection wavelength of 254 nm.)
The amount of methanol-soluble component is 5% by mass or less with respect to 100% by mass of the total amount of methanol-soluble component and methanol-insoluble component,
A methacrylic resin composition characterized by that.
[2]
The resin includes 50 to 95 parts by mass of a methacrylic resin containing a structural unit (X) having a ring structure in the main chain, and 5 to 50 parts by mass of an aromatic vinyl resin.
The glass transition temperature is over 120 ° C. and below 160 ° C.,
The weight average molecular weight (Mw) in terms of polystyrene measured by GPC satisfies the following relationship:
1.1 ≦ Mw _UV / Mw _RI ≦ 2.0
(In the formula, Mw _RI is a weight average molecular weight obtained using a differential refractive index detector, and Mw _UV means a weight average molecular weight obtained using an ultraviolet-visible absorbance detector at a detection wavelength of 254 nm.)
The amount of methanol-soluble component is 5% by mass or less with respect to 100% by mass of the total amount of methanol-soluble component and methanol-insoluble component,
The methacrylic resin composition according to [1], which is characterized in that
[3]
The (X) structural unit includes a structural unit derived from an N-substituted maleimide monomer,
The methacrylic resin composition according to [1], wherein the content of the structural unit derived from the N-substituted maleimide monomer is 5 to 40% by mass with respect to 100% by mass of the methacrylic resin.
[4]
The (X) structural unit includes a lactone ring structural unit,
The methacrylic resin composition according to [1], wherein a content of the lactone ring structural unit is 5 to 40% by mass with respect to 100% by mass of the methacrylic resin.
[5]
The methacrylic resin composition according to any one of [1] to [4], wherein the absolute value of the photoelastic coefficient is 2.0 × 10 ⁻¹² Pa ⁻¹ or less.
[6]
The methacrylic resin composition according to [5], wherein the absolute value of the photoelastic coefficient is 1.0 × 10 ⁻¹² Pa ⁻¹ or less.
[7]
An optical film comprising the methacrylic resin composition according to any one of [1] to [6].
[8]
An optical component, wherein a functional layer is laminated on at least one of the front and back surfaces of the optical film according to [7].
[9]
[8] The functional layer is at least one selected from the group consisting of a hard coat layer, an antiglare (non-glare) layer, an antireflection layer, a light diffusion layer, an antistatic layer, and an ultraviolet shielding layer. Optical component.
[10]
The optical film according to [7] and the optical component according to [8] or [9], wherein the optical film is a retardation film.

  According to the present invention, an optical film having excellent optical properties such as birefringence and having good adhesion to various functional layers laminated on the surface even under severe use environment such as high temperature, high temperature and high humidity. It is possible to provide a methacrylic resin composition that can be prepared, an optical film composed of the methacrylic resin composition, and an optical component in which a functional layer is laminated on the optical film.

  Hereinafter, although the form for implementing this invention (henceforth "this embodiment") is demonstrated in detail, this invention is not limited to the following description, In the range of the summary Various modifications can be made.

(Methacrylic resin composition)
The methacrylic resin composition of the present embodiment includes a resin including a methacrylic resin including a structural unit (X) having a ring structure in the main chain, and including a structural unit (Y) having an aromatic group, Here, the resin may be a single type or a combination of two or more types, and if necessary, other thermoplastic resins, antioxidants, ultraviolet absorbers, and other additives. Including.
More specifically, in the methacrylic resin composition of the present embodiment, the resin is a methacrylic resin including a structural unit (X) having a ring structure in the main chain and a structural unit (Y) having an aromatic group. A methacrylic resin containing a structural unit (X) having a ring structure in the main chain, and a thermoplastic resin containing a structural unit (Y) having an aromatic group compatible with the methacrylic resin. It may be a resin.

As the structural unit (Y) having an aromatic group in the present embodiment, the structural unit derived from the methacrylic acid ester monomer, the structural unit (X) having a ring structure in the main chain (N-substituted maleimide monomer) Body-derived structural units, glutarimide-based structural units, lactone ring structural units) in which any substituent in the structure contains an aromatic group, and further, vinyl having an aromatic group, which will be described later Examples thereof include structural units derived from system monomers.
Examples of the aromatic group herein include aromatic hydrocarbon groups (including monocyclic aromatic hydrocarbon groups and polycyclic aromatic hydrocarbon groups), and more specifically, monocyclic aromatic hydrocarbon groups. Examples of the polycyclic aromatic hydrocarbon group include a phenyl group, a hydroxyphenyl group, and a benzyl group. Examples of the polycyclic aromatic hydrocarbon group include a biphenyl group. In particular, the aromatic group is preferably a group having absorption at a wavelength of 254 nm, and specifically, a substituted or unsubstituted phenyl group is preferable.

-Methacrylic resin-
The methacrylic resin in the present embodiment has a cyclic structure (for example, at least one selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide structural unit, and a lactone ring structural unit) in the main chain. The structural unit (X) which has and the structural unit derived from a methacrylic acid ester monomer is also included.

Examples of the method for producing a methacrylic resin containing the structural unit (X) having a ring structure in the main chain include any polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, and emulsion polymerization. It is done.
In the manufacturing method in the present embodiment, any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method can be used as the polymerization method.
In the production method in the present embodiment, it is preferable to polymerize monomers (details will be described later) by radical polymerization.

  In the following, in particular, each structural unit in the methacrylic resin containing the structural unit (X) having a ring structure in the main chain will be described, and a methacrylic resin having the structural unit, a method for producing the same, and the structural unit will be described. It describes also about the methacrylic resin composition at the time of using a methacrylic resin.

-Structural unit derived from methacrylic acid ester monomer-
First, a structural unit derived from a methacrylic acid ester monomer will be described.
The structural unit derived from a methacrylic acid ester monomer is formed from, for example, a monomer selected from the following methacrylic acid esters. Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, and methacrylic acid. Cyclopentyl, cyclohexyl methacrylate, cyclooctyl methacrylate, tricyclodecyl methacrylate, dicyclooctyl methacrylate, tricyclododecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, 1-phenylethyl methacrylate, methacrylic acid Examples include 2-phenoxyethyl, 3-phenylpropyl methacrylate, 2,4,6-tribromophenyl methacrylate, and the like.
These monomers may be used alone or in combination of two or more.
Of the above methacrylic acid esters, methyl methacrylate and benzyl methacrylate are preferred in that the obtained methacrylic resin is excellent in transparency and weather resistance.
The structural unit derived from a methacrylic acid ester monomer may contain only 1 type, or may contain 2 or more types.

  As a content of the structural unit derived from the methacrylic acid ester monomer, from the viewpoint of sufficiently imparting transparency and weather resistance to the methacrylic resin, the methacrylic resin is taken as 100% by mass, preferably 50 to 95 masses. %, More preferably 55 to 90% by mass, even more preferably 60 to 90% by mass.

--- Structural units derived from aromatic vinyl monomers ---
The structural unit derived from a vinyl monomer having an aromatic group includes an aromatic vinyl monomer copolymerizable with a methacrylic acid ester monomer, and represented by the following general formula (5) Is preferred.

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

Specific examples of the monomer represented by the general formula (5) are not particularly limited, but styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethyl. Styrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyl benzene (α-methylstyrene), isopropenyl toluene, isopropenyl ethyl benzene, isopropenyl propyl benzene, isopropenyl butyl benzene, isopropenyl pentyl benzene, isopropenyl hexyl benzene, Isopropenyl octylben Zen etc. are mentioned.
Among these, styrene and isopropenylbenzene are preferable, and styrene is more preferable from the viewpoint of imparting fluidity and reducing unreacted monomers by improving the polymerization conversion rate.
The aromatic vinyl monomers described above may be used alone or in combination of two or more.

  The content of the structural unit derived from the aromatic vinyl-based monomer is in the range of 0 to 10% by mass, with the methacrylic resin being 100% by mass, considering the balance between heat resistance, reduction of residual monomer species, and fluidity. It is preferably 0.1 to 9% by mass, and more preferably 0.1 to 8% by mass. When the content of the aromatic vinyl unit is in the above range, it is preferable because both heat resistance and excellent photoelastic characteristics can be achieved.

--- Structural unit (X) having a ring structure in the main chain--
In the following, in particular, the structural unit (X) in the methacrylic resin containing the structural unit (X) having a ring structure in the main chain will be described, and a methacrylic resin having the structural unit (X), a method for producing the same, and It describes about the methacrylic resin composition at the time of using the methacrylic resin which has the said structural unit (X).

式（１）中、Ｒ^１は、炭素数７〜１４のアリールアルキル基、炭素数６〜１４のアリール基のいずれかを示し、Ｒ^２及びＲ^３は、それぞれ独立に、水素原子、炭素数１〜１２のアルキル基又は炭素数６〜１４のアリール基のいずれかを示す。
また、Ｒ^２がアリール基の場合には、Ｒ^２は置換基としてハロゲンを含んでいてもよい。
また、Ｒ^１は、ハロゲン原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、ニトロ基、ベンジル基等の置換基で置換されていてもよい。

式（２）中、Ｒ^４は、水素原子、炭素数３〜１２のシクロアルキル基、炭素数１〜１２のアルキル基のいずれかを示し、Ｒ^５及びＲ^６はそれぞれ独立に、水素原子、炭素数１〜１２のアルキル基、炭素数６〜１４のアリール基のいずれかを示す。 --- Structural unit derived from N-substituted maleimide monomer ---
Next, the structural unit derived from the N-substituted maleimide monomer will be described.
The structural unit derived from the N-substituted maleimide monomer may be at least one selected from the monomer represented by the following formula (1) and / or the monomer represented by the following formula (2). Preferably, it is formed from both monomers represented by the following formula (1) and the following formula (2).

In Formula (1), R ¹ represents any of an arylalkyl group having 7 to 14 carbon atoms and an aryl group having 6 to 14 carbon atoms, and R ² and R ³ each independently represent a hydrogen atom or a carbon number. Either an alkyl group having 1 to 12 or an aryl group having 6 to 14 carbon atoms is shown.
When R ² is an aryl group, R ² may contain halogen as a substituent.
R ¹ may be substituted with a substituent such as a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, or a benzyl group.

In Formula (2), R ⁴ represents any one of a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms, and R ⁵ and R ⁶ are each independently a hydrogen atom, One of an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 14 carbon atoms is shown.

Specific examples will be shown below.
Examples of the monomer represented by the formula (1) include N-phenylmaleimide, N-benzylmaleimide, N- (2-chlorophenyl) maleimide, N- (4-chlorophenyl) maleimide, N- (4-bromo Phenyl) maleimide, N- (2-methylphenyl) maleimide, N- (2-ethylphenyl) maleimide, N- (2-methoxyphenyl) maleimide, N- (2-nitrophenyl) maleimide, N- (2,4 , 6-Trimethylphenyl) maleimide, N- (4-benzylphenyl) maleimide, N- (2,4,6-tribromophenyl) maleimide, N-naphthylmaleimide, N-anthracenylmaleimide, 3-methyl-1 -Phenyl-1H-pyrrole-2,5-dione, 3,4-dimethyl-1-phenyl-1H-pyrrole-2,5- One, 1,3-diphenyl -1H- pyrrole-2,5-dione, 1,3,4-triphenyl -1H- pyrrole-2,5-dione, and the like.
Among these monomers, N-phenylmaleimide and N-benzylmaleimide are preferable because the obtained methacrylic resin has excellent heat resistance and optical properties such as birefringence.
These monomers may be used alone or in combination of two or more.

Examples of the monomer represented by the formula (2) include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, Ns-butylmaleimide, Nt-butylmaleimide, Nn-pentylmaleimide, Nn-hexylmaleimide, Nn-heptylmaleimide, Nn-octylmaleimide, N-laurylmaleimide, N-cyclopentyl Maleimide, N-cyclohexylmaleimide, 1-cyclohexyl-3-methyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-dimethyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3 -Phenyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3, - diphenyl -1H- pyrrole-2,5-dione, and the like.
Among these monomers, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide are preferable because the weather resistance of the methacrylic resin is excellent. N-cyclohexylmaleimide is particularly preferable because of its excellent hygroscopicity.
These monomers can be used alone or in combination of two or more.

In the methacrylic resin of the present embodiment, using the monomer represented by the formula (1) and the monomer represented by the formula (2) in combination provides highly controlled birefringence characteristics. It is particularly preferable because it can be expressed.
The molar ratio of the content (B1) of the structural unit derived from the monomer represented by formula (1) to the content (B2) of the structural unit derived from the monomer represented by formula (2), (B1 / B2) is preferably more than 0 and 15 or less, more preferably more than 0 and 10 or less. When the molar ratio (B1 / B2) is in this range, the methacrylic resin of the present embodiment maintains transparency, does not cause yellowing, and does not impair the environmental resistance. Expresses photoelastic properties.

The content of a structural unit derived from N- substituted maleimide monomer, but the resulting composition is not particularly limited as long as it satisfies the range of the glass transition temperature of this embodiment, as 100% by mass of the methacrylic resin , Preferably it is the range of 5-40 mass%, More preferably, it is the range of 5-35 mass%.
When it is within this range, the methacrylic resin can obtain a more sufficient heat resistance improving effect, and more preferable effects of improving weather resistance, low water absorption, and optical properties. It should be noted that the content of the structural unit derived from the N-substituted maleimide monomer being 40% by mass or less reduces the reactivity of the monomer component during the polymerization reaction and increases the amount of unreacted monomer. This is effective in preventing deterioration in physical properties of the methacrylic resin.

  In particular, the content of the structural unit derived from the monomer represented by the formula (1) (the structural unit derived from the N-arylmaleimide monomer) is 3 to 20% by mass based on 100% by mass of the methacrylic resin. It is preferable that it is the range of 5-18 mass%, It is more preferable that it is 7-16 mass%. When the content of the structural unit derived from the N-arylmaleimide monomer is in the above range, it is preferable because both heat resistance and excellent photoelastic properties can be achieved.

The methacrylic resin having a structural unit derived from an N-substituted maleimide monomer in the present embodiment can be copolymerized with a methacrylic acid ester monomer and an N-substituted maleimide monomer as long as the object of the present invention is not impaired. It may contain structural units derived from other monomers.
For example, other copolymerizable monomers include aromatic vinyl; unsaturated nitrile; cyclohexyl group, benzyl group, or acrylate ester having an alkyl group having 1 to 18 carbon atoms; glycidyl compound; unsaturated carboxylic acid Etc. Examples of the aromatic vinyl include those represented by the above general formula (5), and specific examples include styrene, α-methylstyrene, divinylbenzene, and the like. Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like. Examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate. Examples of the glycidyl compound include glycidyl acrylate and allyl glycidyl ether. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and half-esterified products or anhydrides thereof.
The structural unit derived from the other copolymerizable monomer may have only one type, or may have two or more types.

The content of structural units derived from these other copolymerizable monomers is preferably 0 to 10% by mass, more preferably 0 to 9% by mass, based on 100% by mass of the methacrylic resin. Preferably, it is more preferable that it is 0-8 mass%.
When the content of the structural unit derived from another monomer is within this range, it is preferable because the processability and mechanical properties of the resin can be improved without impairing the original effect of introducing a ring structure into the main chain.

As a method for producing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer in the main chain, any polymerization method of bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, and emulsion polymerization Preferred are suspension polymerization, bulk polymerization, and solution polymerization, and more preferred is solution polymerization.
In the manufacturing method in the present embodiment, any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method can be used as the polymerization method.
In the production method in the present embodiment, it is preferable to polymerize the monomer by radical polymerization.

Hereinafter, as an example of a method for producing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer (hereinafter sometimes referred to as “maleimide copolymer”), it is produced by radical polymerization using a solution polymerization method. The case where it does is demonstrated concretely.
In the present embodiment, a method in which a part of the monomer is charged into the reactor before the start of polymerization, the polymerization is started by adding a polymerization initiator, and then the remainder of the monomer is supplied, so-called semi-batch weight. A legal method (also referred to as a semi-batch method) can be preferably used. By adopting this method, it tends to be easy to control the molecular weight distribution and composition distribution of the polymer obtained.

Here, the ratio of the amount of monomer (at the start of polymerization) used in the initial charge and the amount of monomer added after the start of polymerization is a mass ratio, preferably in the range of 1: 9 to 8: 2. More preferably, it is the range of 2: 8-7.5: 2.5, More preferably, it is the range of 3: 7-5: 5.
If the amount ratio of the monomers is within the above range, it is possible to appropriately select the monomer mixture composition in the initial charge in consideration of the copolymerization reactivity of each monomer used during copolymerization. It tends to be easier to control the composition distribution of the resulting polymer.

The polymerization solvent to be used is not particularly limited as long as the solubility of the maleimide copolymer obtained by polymerization is increased and the viscosity of the reaction solution can be appropriately maintained for the purpose of preventing gelation.
Specific examples of the polymerization solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and isopropylbenzene; ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone; polar solvents such as dimethylformamide and 2-methylpyrrolidone. Can be used.
Moreover, you may use together alcohol, such as methanol, ethanol, and isopropanol, as a polymerization solvent in the range which does not inhibit melt | dissolution of the polymerization product at the time of superposition | polymerization.

  The amount of solvent at the time of polymerization is not particularly limited as long as the polymerization proceeds and the copolymer or used monomer does not precipitate during production and can be easily removed. When the total amount is 100 parts by mass, it is preferably 10 to 200 parts by mass. More preferably, it is 25-200 mass parts, More preferably, it is 50-200 mass parts, More preferably, it is 50-150 mass parts.

  The polymerization temperature is not particularly limited as long as the polymerization proceeds, but is preferably 50 to 200 ° C., more preferably 80 to 200 ° C. from the viewpoint of productivity. More preferably, it is 90-150 degreeC, More preferably, it is 100-140 degreeC, More preferably, it is 100-130 degreeC.

  Further, the polymerization time is not particularly limited as long as the required degree of polymerization can be obtained at the required conversion rate, but it is preferably 0.5 to 10 hours from the viewpoint of productivity and the like. More preferably, it is 1 to 8 hours.

  During the polymerization reaction, polymerization may be performed by adding a polymerization initiator or a chain transfer agent as necessary.

As the polymerization initiator, any initiator generally used in radical polymerization can be used. For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide Organic peroxides such as oxide, t-butylperoxyisopropyl carbonate, t-amylperoxy-2-ethylhexanoate, t-amylperoxyisononanoate, 1,1-di-t-butylperoxycyclohexane; 2,2'-azobis (isobutyronitrile), 1,1'-azobis (cyclohexanecarbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis Azo compounds such as isobutyrate; it can.
These may be used alone or in combination of two or more.
The addition amount of the polymerization initiator may be 0.01 to 1 part by mass, preferably 0.05 to 0.5 part by mass, when the total amount of monomers used for polymerization is 100 parts by mass. is there.

These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress.
In this embodiment, the type of initiator, the amount of initiator, the polymerization temperature, etc. so that the ratio of the total amount of radicals generated from the polymerization initiator to the total amount of unreacted monomers remaining in the reaction system is always below a certain value. Is preferably selected as appropriate.
In particular, in the present embodiment, at least once in the first half of the time from the start of addition of the polymerization initiator to the end of the addition (polymerization initiator addition time), the addition amount per unit time of the polymerization initiator is It is preferable to make it smaller than the addition amount per unit time.
By adopting this method, it is possible to suppress the production amount of oligomers and low molecular weight substances in the later stage of polymerization, or to suppress the overheating at the time of polymerization and to achieve the stability of polymerization.

As the chain transfer agent, a chain transfer agent used in general radical polymerization can be used, for example, n-butyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, 2-ethylhexyl thioglycolate and the like. Mercaptan compounds; halogen compounds such as carbon tetrachloride, methylene chloride and bromoform; unsaturated hydrocarbon compounds such as α-methylstyrene dimer, α-terpinene, dipentene and terpinolene;
These may be used alone or in combination of two or more.
These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and are not particularly limited.
The addition amount of the chain transfer agent may be 0.01 to 1 part by mass, preferably 0.05 to 0.5 part by mass, when the total amount of monomers used for polymerization is 100 parts by mass.

  In solution polymerization, it is important to reduce the dissolved oxygen concentration in the polymerization solution as much as possible. For example, the dissolved oxygen concentration is preferably 10 ppm or less. The dissolved oxygen concentration can be measured using, for example, a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.). As a method for lowering the dissolved oxygen concentration, a method of bubbling an inert gas in the polymerization solution, and an operation of releasing the pressure after pressurizing the container containing the polymerization solution with an inert gas to about 0.2 MPa before the polymerization are repeated. A method such as a method and a method of passing an inert gas in a container containing a polymerization solution can be appropriately selected.

  The method for recovering the polymer from the polymerization solution obtained by solution polymerization is not particularly limited. For example, a poor solvent such as a hydrocarbon solvent or alcohol solvent that does not dissolve the polymerization product obtained by polymerization. After adding the polymerization liquid in the presence of an excessive amount, the homogenizer is treated (emulsified and dispersed), and the unreacted monomer is subjected to pretreatment such as liquid-liquid extraction and solid-liquid extraction. Examples include a method of separating from a polymerization solution; or a method of separating a polymerization solvent and unreacted monomers via a step called a devolatilization step and recovering a polymerization product.

Here, the devolatilization step refers to a step of removing volatile components such as a polymerization solvent, a residual monomer, and a reaction by-product under heating and reduced pressure conditions.
As an apparatus used for the devolatilization process, for example, a devolatilization apparatus comprising a tubular heat exchanger and a devolatilization tank; thin film evaporators such as Wibren manufactured by Shinko Environmental Solution Co., Ltd. And a vented extruder having sufficient residence time and surface area to exhibit devolatilization performance.
A devolatilization process using a devolatilizer in which any two or more of these apparatuses are combined can also be used.

The treatment temperature in the devolatilizer is preferably 150 to 350 ° C, more preferably 170 to 300 ° C, and further preferably 200 to 280 ° C. When this temperature is 150 ° C. or higher, it is effective to prevent the residual volatile matter from increasing. On the contrary, when this temperature is 350 ° C. or lower, there is little possibility that coloring or decomposition of the resulting methacrylic resin occurs.
The degree of vacuum in the devolatilizer may be in the range of 10 to 500 Torr, and in particular, the range of 10 to 300 Torr is preferable. When the degree of vacuum is 500 Torr or less, volatile components tend not to remain, and when the degree of vacuum is 10 Torr or more, industrial implementation is easier.
The treatment time is appropriately selected depending on the amount of residual volatile matter, but is preferably as short as possible in order to suppress coloring and decomposition of the resulting methacrylic resin.

  The polymer recovered through the devolatilization process is processed into a pellet in a process called a granulation process.

  In the granulation step, the molten resin is extruded into a strand shape from a perforated die and processed into pellets by a cold cut method, an air hot cut method, an underwater strand cut method, and an underwater cut method.

  In addition, when an extruder with a vent is employ | adopted as a devolatilization apparatus, you may serve as a devolatilization process and a granulation process.

In the present embodiment, as will be described later, the weight average molecular weight and the molecular weight distribution are determined by performing measurement using two different types of detectors. The weight average molecular weight determined using the detector is Mw _RI , the molecular weight distribution is (Mw / Mn) _{RI ,} the weight average molecular weight determined using the UV-visible absorbance detector is Mw _UV , and the molecular weight distribution is (Mw / Mn). Mn) _UV .

In this embodiment, ranges of weight average molecular weight (Mw _RI ) measured using a differential refractive index detector of methacrylic resin used for mixing and preparing two or more kinds are 70,000 to 800,000, respectively. You may select arbitrarily from the range.
When the weight average molecular weight (Mw _RI ) is low (hereinafter referred to as “low molecular weight component”), the weight average molecular weight is preferably in the range of 70,000 to 150,000, in particular 100,000. More preferably, it is in the range of ˜150,000. The molecular weight distribution (Mw / Mn) _RI is preferably in the range of 1.5 to 2.5.
In the case of a material having a high weight average molecular weight (Mw _RI ) (hereinafter referred to as “high molecular weight component”), the weight average molecular weight is preferably in the range of 220,000 to 800,000, and in particular, 220,000 More preferably, it is in the range of ~ 600,000. The molecular weight distribution (Mw / Mn) _RI is preferably in the range of 2.5 to 4.0.
Although there is no restriction | limiting in particular as a mixing ratio of the low molecular weight component and high molecular weight component in this embodiment, It can select suitably from the range of 5-95 mass parts of low molecular weight components and 95-5 mass parts of high molecular weight components. .

  By mixing two or more methacrylic resins as described above, a resin composition suitable for an optical film having a functional layer can be provided.

In the present embodiment, the method of mixing two or more methacrylic resins having different weight average molecular weights (Mw _RI ) is not particularly limited, but polymers having different weight average molecular weights obtained by the polymerization reaction described above are used. Adopting a method of mixing a solution containing two or more kinds in a liquid phase and then performing a devolatilization step treatment or a precipitation treatment by adding a poor solvent; a method of mixing using a melt-kneading apparatus such as an extruder; Can do. When using a methacrylic resin having a particularly high molecular weight, a solution containing two or more polymers obtained by the polymerization reaction is mixed in the liquid phase, and then precipitated by treatment in a devolatilization step or addition of a poor solvent. It is preferable to use a method of performing the treatment.

上記一般式（３）において、好ましくはＲ^７，及び Ｒ^８は、それぞれ独立して、水素又はメチル基であり 、Ｒ^９は、水素、メチル基、ブチル基、シクロヘキシル基のいずれかであり、より好ましくは 、Ｒ^７は、メチル基であり、Ｒ^８は、水素であり、Ｒ^９は、メチル基である。 --- Glutarimide structural unit ---
The glutarimide-based structural unit in the present embodiment may be represented by the following general formula (3).

In the general formula (3), preferably R ⁷ and R ⁸ are each independently hydrogen or a methyl group, and R ⁹ is any one of hydrogen, a methyl group, a butyl group, and a cyclohexyl group, More preferably, R ⁷ is a methyl group, R ⁸ is hydrogen, and R ⁹ is a methyl group.

  The glutarimide-based structural unit may include only a single type or a plurality of types.

In the methacrylic resin having a glutarimide-based structural unit, the content of the glutarimide-based structural unit is not particularly limited as long as it satisfies the glass transition temperature range preferable as the composition of the present embodiment. 100 mass% of resin, Preferably it is the range of 5-70 mass%, More preferably, it is the range of 5-60 mass%.
When the content of the glutarimide-based structural unit is in the above range, a resin having good moldability, heat resistance, and optical properties is preferable.

The methacrylic resin having a glutarimide-based structural unit may further contain an aromatic vinyl monomer unit as necessary.
Although it does not specifically limit as an aromatic vinyl monomer, What is represented by the above-mentioned general formula (5) is mentioned.

The content of the aromatic vinyl unit in the methacrylic resin having a glutarimide-based structural unit is not particularly limited, but is preferably in the range of 0 to 10% by mass with 100% by mass of the methacrylic resin. It is more preferable that it is 9 mass%, and it is still more preferable that it is 0-8 mass%.
When the content of the aromatic vinyl unit is in the above range, it is preferable because both heat resistance and excellent photoelastic characteristics can be achieved.

  A methacrylic resin having a glutarimide-based structural unit in the main chain is disclosed in, for example, JP-A-2006-249202, JP-A-2007-009182, JP-A-2007-009191, JP-A-2011-186482, It is a methacrylic resin having a glutarimide-based structural unit described in Japanese Patent Publication No. 2012/114718, and can be formed by the method described in the publication.

上記一般式（４）において、Ｒ^１０、Ｒ^１１及びＲ^１２は、互いに独立して、水素原子、又は炭素数１〜２０の有機残基である。
有機残基としては、例えば、メチル基、エチル基、プロピル基等の炭素数１〜２０の飽和脂肪族炭化水素基（アルキル基等）；エテニル基、プロペニル基等の炭素数２〜２０の不飽和脂肪族炭化水素基（アルケニル基等）；フェニル基、ナフチル基等の炭素数６〜２０の芳香族炭化水素基（アリール基等）；これら飽和脂肪族炭化水素基、不飽和脂肪族炭化水素基、芳香族炭化水素基における水素原子の一つ以上が、ヒドロキシ基、カルボキシル基、エーテル基、エステル基からなる群から選ばれる少なくとも１種の基により置換された基；等が挙げられる。 --- Lactone ring structural unit ---
The lactone ring structural unit in the present embodiment is preferably a 6-membered ring because it is excellent in the stability of the ring structure.
As the lactone ring structural unit which is a 6-membered ring, for example, a structure represented by the following general formula (4) is particularly preferable.

In the general formula (4), R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms.
Examples of the organic residue include saturated aliphatic hydrocarbon groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, and a propyl group (alkyl groups and the like); Saturated aliphatic hydrocarbon group (alkenyl group etc.); C6-C20 aromatic hydrocarbon group (aryl group etc.) such as phenyl group, naphthyl group; These saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbons Group, a group in which one or more hydrogen atoms in the aromatic hydrocarbon group are substituted with at least one group selected from the group consisting of a hydroxy group, a carboxyl group, an ether group, and an ester group.

  The lactone ring structure is obtained by, for example, copolymerizing an acrylic acid-based monomer having a hydroxy group and a methacrylic acid ester monomer such as methyl methacrylate to form a hydroxy group and an ester group or a carboxyl group in the molecular chain. After the introduction, it can be formed by causing dealcoholization (esterification) or dehydration condensation (hereinafter also referred to as “cyclization condensation reaction”) between these hydroxy groups and ester groups or carboxyl groups.

  Examples of the acrylic acid-based monomer having a hydroxy group used for polymerization include 2- (hydroxymethyl) acrylic acid, 2- (hydroxyethyl) acrylic acid, 2- (hydroxymethyl) alkyl acrylate (for example, 2- (Hydroxymethyl) methyl acrylate, 2- (hydroxymethyl) ethyl acrylate, 2- (hydroxymethyl) isopropyl acrylate, 2- (hydroxymethyl) acrylate n-butyl, 2- (hydroxymethyl) acrylate t- Butyl), 2- (hydroxyethyl) alkyl acrylate, and the like, preferably 2- (hydroxymethyl) acrylic acid and 2- (hydroxymethyl) alkyl acrylate which are monomers having a hydroxyallyl moiety. , Particularly preferably methyl 2- (hydroxymethyl) acrylate 2- (hydroxymethyl) acrylate.

The content of the lactone ring structural unit in the methacrylic resin having a lactone ring structural unit in the main chain is not particularly limited as long as it satisfies the glass transition temperature range preferable as the composition of the present embodiment. It is preferable that it is 5-40 mass% with respect to 100 mass%, More preferably, it is the range of 5-35 mass%.
When the content of the lactone ring structural unit is within this range, effects of introducing a ring structure such as improvement in solvent resistance and improvement in surface hardness can be exhibited while maintaining moldability.
In addition, the content rate of the lactone ring structure in a methacrylic resin can be determined using the method described above in the patent document.

The methacrylic resin having a lactone ring structural unit may have a structural unit derived from another monomer copolymerizable with the above-mentioned methacrylic acid ester monomer and an acrylic acid monomer having a hydroxy group. Good.
Examples of such other copolymerizable monomers include aromatic vinyl; acrylonitrile, methacrylonitrile, methallyl alcohol, allyl alcohol, ethylene, propylene, 4-methyl-1-pentene, vinyl acetate, 2 And monomers having a polymerizable double bond such as -hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, and N-vinyl carbazole. Although it does not specifically limit as an aromatic vinyl monomer, What is represented by the above-mentioned general formula (5) is mentioned.
These other monomers (structural units) may have only one type or two or more types.
Among these, an aromatic vinyl monomer is particularly preferable from the viewpoint of obtaining a suitable composition distribution in the resin composition of the present embodiment.

The content of structural units derived from these other copolymerizable monomers is preferably in the range of 0 to 10% by mass, and in the range of 0 to 9% by mass with respect to 100% by mass of the methacrylic resin. It is more preferable that it is 0-8 mass%.
The methacrylic resin in this embodiment may have only one type of structural unit derived from the above copolymerizable other monomer, or may have two or more types.

  Examples of the methacrylic resin having a lactone ring structural unit in the main chain include, for example, JP-A No. 2001-151814, JP-A No. 2004-168882, JP-A No. 2005-146084, JP-A No. 2006-96960, and JP-A No. 2006-96960. It can be formed by the methods described in JP-A-2006-171464, JP-A-2007-63541, JP-A-2007-297620, JP-A-2010-180305, and the like.

Specifically, as a method for producing a methacrylic resin having a lactone ring structural unit in the main chain, a method of forming a lactone ring structure by a cyclization reaction after polymerization is used, but in order to promote the cyclization reaction, The monomer is preferably polymerized by radical polymerization by a solution polymerization method using a solvent.
In the manufacturing method in this embodiment, any of a batch polymerization method, a semi-batch method, and a continuous polymerization method can be used as a polymerization format, for example.

Hereinafter, the case where it manufactures by radical polymerization using a solution polymerization method as an example of a manufacturing method is demonstrated concretely.
In the present embodiment, a method in which a part of the monomer is charged into the reactor before the start of polymerization, the polymerization is started by adding a polymerization initiator, and then the remainder of the monomer is supplied, so-called semi-batch weight. A legal method (also referred to as a semi-batch method) can be preferably used. By adopting this method, it tends to be easy to control the molecular weight distribution and composition distribution of the polymer obtained.

Here, the ratio of the amount of monomer (at the start of polymerization) used in the initial charge and the amount of monomer added after the start of polymerization is a mass ratio, preferably in the range of 1: 9 to 8: 2. More preferably, it is the range of 2: 8-7.5: 2.5, More preferably, it is the range of 3: 7-5: 5.
If the amount ratio of the monomers is within the above range, it is possible to appropriately select the monomer mixture composition in the initial charge in consideration of the copolymerization reactivity of each monomer used during copolymerization. It tends to be easier to control the composition distribution of the resulting polymer.

Examples of the solvent used for the polymerization include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone;
These solvents may be used alone or in combination of two or more.

  The amount of solvent at the time of polymerization is not particularly limited as long as the polymerization proceeds and gelation can be suppressed. For example, when the total amount of monomers to be blended is 100 parts by mass, 50 to 200 masses Part, preferably 100 to 200 parts by mass.

In order to sufficiently suppress the gelation of the polymerization solution and promote the cyclization reaction after polymerization, the polymerization is performed so that the concentration of the produced polymer in the reaction mixture obtained after the polymerization is 50% by mass or less. It is preferable to add a polymerization solvent to the reaction mixture as appropriate and control it to 50% by mass or less.
The method for appropriately adding the polymerization solvent to the reaction mixture is not particularly limited, and for example, the polymerization solvent may be added continuously or the polymerization solvent may be added intermittently.
The polymerization solvent to be added may be only one kind of single solvent or two or more kinds of mixed solvents.

  The polymerization temperature is not particularly limited as long as the polymerization proceeds, but it is preferably 50 to 200 ° C from the viewpoint of productivity, more preferably 80 to 150 ° C, and still more preferably 90 to 130 ° C. It is.

  The polymerization time is not particularly limited as long as the target conversion rate is satisfied, but is preferably 0.5 to 10 hours, more preferably 1 to 8 hours from the viewpoint of productivity and the like.

  During the polymerization reaction, polymerization may be performed by adding a polymerization initiator or a chain transfer agent as necessary.

Although it does not specifically limit as a polymerization initiator, For example, the polymerization initiator etc. which were disclosed by the preparation method of the methacryl resin which has a structural unit derived from the said N-substituted maleimide monomer can be utilized.
These polymerization initiators may be used alone or in combination of two or more.
The amount of the polymerization initiator used may be appropriately set according to the combination of monomers and reaction conditions, and is not particularly limited. However, when the total amount of monomers used for polymerization is 100 parts by mass Furthermore, it is good as 0.05-1 mass part.

These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress.
In this embodiment, the type of initiator, the amount of initiator, the polymerization temperature, etc. so that the ratio of the total amount of radicals generated from the polymerization initiator to the total amount of unreacted monomers remaining in the reaction system is always below a certain value. Is preferably selected as appropriate.
In particular, in the present embodiment, at least once in the first half of the time from the start of addition of the polymerization initiator to the end of the addition (polymerization initiator addition time), the addition amount per unit time of the polymerization initiator is It is preferable to make it smaller than the addition amount per unit time.
By adopting this method, it is possible to suppress the formation of oligomers and low molecular weight components in the later stage of polymerization, and to achieve the stability of polymerization by suppressing overheating during polymerization.

As the chain transfer agent, a chain transfer agent used in general radical polymerization can be used. For example, the chain transfer agent disclosed in the method for preparing a methacrylic resin having a structural unit derived from the N-substituted maleimide monomer is used. it can.
These may be used alone or in combination of two or more.
These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and are not particularly limited.
The amount of chain transfer agent used is not particularly limited as long as a desired degree of polymerization can be obtained under the polymerization conditions used, but preferably the total amount of monomers used for polymerization is 100 parts by mass. When it does, it is good as a range of 0.05-1 mass part.

The methacrylic resin having a lactone ring structural unit in the present embodiment can be obtained by performing a cyclization reaction after completion of the polymerization reaction. Therefore, it is preferable to use the lactone cyclization reaction in a state containing a solvent without removing the polymerization solvent from the polymerization reaction solution.
The copolymer obtained by polymerization undergoes a heat treatment to cause a cyclization condensation reaction between a hydroxyl group (hydroxyl group) present in the molecular chain of the copolymer and an ester group, and a lactone ring structure. Form.

During the heat treatment for forming the lactone ring structure, a vacuum apparatus or a reaction apparatus equipped with a devolatilization apparatus for removing alcohol that may be by-produced by cyclization condensation, an extruder equipped with a devolatilization apparatus, or the like can be used. .
When forming the lactone ring structure, heat treatment may be performed using a cyclization condensation catalyst, if necessary, in order to promote the cyclization condensation reaction.
Specific examples of the cyclization condensation catalyst include, for example, methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, diphenyl phosphite, trimethyl phosphite, Phosphorous acid monoalkyl ester, dialkyl ester or triester such as triethyl phosphate; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate, lauryl phosphate, stearyl phosphate, phosphoric acid Isostearyl, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diisostearyl phosphate, trimethyl phosphate, triethyl phosphate, triisodecyl phosphate, Trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate Phosphoric acid monoalkyl esters and the like, dialkyl ester or trialkyl esters; and the like are.
These may be used alone or in combination of two or more.
The amount of the cyclization condensation catalyst is not particularly limited, but is preferably 0.01 to 3 parts by mass, more preferably 0.05 to 100 parts by mass with respect to 100 parts by mass of the methacrylic resin. 1 part by mass.
When the amount of the catalyst used is 0.01 parts by mass or more, it is effective for improving the reaction rate of the cyclization condensation reaction, and when the amount of the catalyst used is 3 parts by mass or less, the obtained polymer is colored. In addition, it is effective to prevent the polymer from cross-linking and difficult to be melt-molded.

  The addition timing of the cyclization condensation catalyst is not particularly limited. For example, it may be added at the initial stage of the cyclization condensation reaction, may be added during the reaction, or may be added both. Good.

It is also preferable to perform devolatilization at the same time when the cyclization condensation reaction is performed in the presence of a solvent.
There are no particular limitations on the equipment used when the cyclization condensation reaction and the devolatilization step are performed simultaneously, but a devolatilizer comprising a heat exchanger and a devolatilization tank, an extruder with a vent, and devolatilization are also included. A device in which an apparatus and an extruder are arranged in series is preferable, and a twin screw extruder with a vent is more preferable.

The vented twin screw extruder is preferably a vented extruder having a plurality of vent ports.
The reaction treatment temperature when using an extruder with a vent is preferably 150 to 350 ° C, more preferably 200 to 300 ° C. When the reaction treatment temperature is 150 ° C. or higher, it is effective to prevent the cyclization condensation reaction from being insufficient and the residual volatile content to increase, and when the reaction treatment temperature is 350 ° C. or less, it was obtained. It is effective in suppressing the coloring and decomposition of the polymer.
The degree of vacuum when using an extruder with a vent is preferably 10 to 500 Torr, more preferably 10 to 300 Torr. When the degree of vacuum is 500 Torr or less, volatile components tend not to remain. Conversely, when the degree of vacuum is 10 Torr or more, industrial implementation is relatively easy.

It is also preferable to add an alkaline earth metal and / or amphoteric metal salt of an organic acid during granulation for the purpose of deactivating the remaining cyclization condensation catalyst when performing the cyclization condensation reaction.
As the alkaline earth metal and / or amphoteric metal salt of an organic acid, for example, calcium acetyl acetate, calcium stearate, zinc acetate, zinc octylate, zinc 2-ethylhexylate and the like can be used.
After passing through the cyclocondensation reaction step, the methacrylic resin is melted and extruded in a strand form from an extruder with a perforated die, and is cold-cut, aerial hot-cut, underwater strand-cut, and underwater-cut. Process into pellets.

  Here, a suitable methacrylic resin composition in the present embodiment will be described.

As the methacrylic resin composition of the present embodiment, from the viewpoint of obtaining a suitable composition distribution,
A methacrylic resin containing structural units (X) having the same type of ring structure in the main chain and structural units (Y) having an aromatic group in different proportions and having different weight average molecular weights is used as the resin in this embodiment. And a methacrylic resin composition containing a structural unit (X) having a cyclic structure in the main chain, having different weight average molecular weights, and compatibility with the methacrylic resin. And a methacrylic resin composition containing a resin containing a thermoplastic resin containing a structural unit (Y) having an aromatic group.

  Examples of the thermoplastic resin containing a structural unit (Y) having an aromatic group compatible with a methacrylic resin include a resin containing an aromatic vinyl monomer represented by the general formula (5), For example, aromatic vinyl resins such as polystyrene, styrene polymers such as styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; Etc.

  Among these, from the viewpoint of obtaining a preferable composition distribution, an aromatic vinyl resin is preferable. Among them, from the viewpoint of obtaining good compatibility with a methacrylic resin, for example, a styrene-acrylonitrile copolymer, an acrylonitrile-butadiene-styrene block, and the like. Examples thereof include styrenic polymers such as copolymers.

In the resin in the above preferred methacrylic resin composition, the content of the methacrylic resin containing the structural unit (X) having a ring structure in the main chain is 50 to 95% by mass with respect to 100% by mass of the resin. Is preferable, more preferably 70 to 95% by mass, and particularly preferably 80 to 90% by mass.
The content of the aromatic vinyl resin is preferably 5 to 50% by mass, more preferably 5 to 30% by mass, particularly preferably 10 to 20% by mass, based on 100% by mass of the resin. is there.

  In the present embodiment, as long as the characteristics specified in the present embodiment are satisfied, the proportion of the structural unit derived from the monomer, the weight average molecular weight, and the molecular weight distribution are different in each type of resin included in the resin composition. The mixing ratio of these types of resins is preferably selected as appropriate.

In this embodiment, the range of the weight average molecular weight (Mw _RI ) of the methacrylic resin and the aromatic vinyl resin having compatibility with the methacrylic resin used when preparing the methacrylic resin composition is as follows. , 70,000 to 800,000 may be arbitrarily selected.
When the weight average molecular weight (Mw _RI ) is low (hereinafter referred to as “low molecular weight component”), the weight average molecular weight is preferably in the range of 70,000 to 150,000, in particular 100,000. More preferably, it is in the range of ˜150,000. The molecular weight distribution (Mw / Mn) _RI is preferably in the range of 1.5 to 2.5.
In the case of a material having a high weight average molecular weight (Mw _RI ) (hereinafter referred to as “high molecular weight component”), the weight average molecular weight is preferably in the range of 220,000 to 800,000, and in particular, 220,000 More preferably, it is in the range of ~ 600,000. The molecular weight distribution (Mw / Mn) _RI is preferably in the range of 2.5 to 4.0.
Although there is no restriction | limiting in particular as a mixing ratio of the low molecular weight component and high molecular weight component in this embodiment, It can select suitably from the range of 5-95 mass parts of low molecular weight components and 95-5 mass parts of high molecular weight components. .

As described above, it is suitable for optical films having a functional layer by mixing two or more methacrylic resins, or by mixing a methacrylic resin, the methacrylic resin, and a compatible aromatic vinyl resin. A resin composition can be provided.

In the present embodiment, the method of mixing two or more methacrylic resins having different weight average molecular weights (Mw _RI ) is not particularly limited, but polymers having different weight average molecular weights obtained by the polymerization reaction described above are used. A method of mixing a solution containing two or more kinds in a liquid phase and then performing a devolatilization step treatment or a precipitation treatment by adding a poor solvent; a method of mixing using a melt-kneading apparatus such as an extruder; be able to. When using a methacrylic resin having a particularly high molecular weight, a solution containing two or more polymers obtained by the polymerization reaction is mixed in the liquid phase, and then precipitated by treatment in a devolatilization step or addition of a poor solvent. It is preferable to use a method of performing the treatment.
The methacrylic resin in this embodiment preferably has at least one ring structural unit selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide structural unit, and a lactone ring structural unit. Among these, it is particularly preferable to have a structural unit derived from an N-substituted maleimide monomer from the viewpoint of highly controlling optical properties such as a photoelastic coefficient without blending with other thermoplastic resins.

-Other thermoplastic resins-
When preparing the methacrylic resin composition of the present embodiment, other thermoplastic resins may be blended for the purpose of adjusting the birefringence and improving flexibility without impairing the purpose of the present embodiment. it can.
Other thermoplastic resins include, for example, polyacrylates such as polybutyl acrylate; and further, JP-A-59-202213, JP-A-63-27516, JP-A-51-129449, Acrylic rubber particles having a three- to four-layer structure described in Japanese Utility Model Laid-Open No. 52-56150; a rubbery polymer disclosed in Japanese Patent Publication No. 60-17406 and Japanese Patent Laid-Open No. 8-245854; And methacrylic rubber-containing graph soot copolymer particles obtained by multistage polymerization as described in JP-A No. 2014-002491.

  Among these, from the viewpoint of obtaining good optical properties and mechanical properties, a graft portion having a composition compatible with a methacrylic resin containing a structural unit (X) having a ring structure in the main chain is formed on the surface layer. The rubber-containing graft copolymer particles are preferred. As the average particle diameter of the acrylic rubber particles, methacrylic rubber-containing graph copolymer particles, and rubbery polymers, the impact strength and optical characteristics of the film obtained from the methacrylic resin composition of the present embodiment, etc. From the viewpoint of increasing the thickness, it is preferably 0.03 to 1 μm, more preferably 0.05 to 0.5 μm.

  The content of the other thermoplastic resin is preferably 0 to 50 parts by mass, more preferably 0 to 25 parts by mass when the methacrylic resin is 100 parts by mass.

-Antioxidant-
In the methacrylic resin composition according to the present embodiment, hindered phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants are exhibited in order to exhibit the original polymer characteristics of the methacrylic resin of the present embodiment. It is preferable to add an antioxidant such as an agent. These may be used alone or in combination of two or more.

Specific examples of the hindered phenol antioxidant include, but are not limited to, 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 ″-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6 -Bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-t rt-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [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-triazin-2-ylamine) phenol, acrylic acid 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl]- 4, - di -tert- pentylphenyl, acrylic acid 2-tert-butyl-4-methyl-6- (2-hydroxy -3-tert-butyl-5-methylbenzyl) phenyl and the like.
In particular, pentaerythritol terakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, Acrylic acid 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl is preferred.

The hindered phenolic antioxidant may be a commercially available phenolic antioxidant. Such a commercially available phenolic antioxidant is not limited to the following, for example: Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by BASF), Irganox 1076 (Irganox 1076: octadecyl) -3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (manufactured by BASF), Irganox 1330 (Irganox 1330: 3, 3 ′, 3 ″, 5, 5 ′, 5 ″) -Hexa-t-butyl-a, a ', a''-(mesitylene-2,4,6-triyl) tri-p- Resole, 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), Adekastab (registered trademark) AO-60 (pentaerythritol tetrakis [3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate], manufactured by ADEKA), ADK STAB AO-80 (3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] Oxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, AD KA), Sumilizer (registered trademark) BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox (registered trademark) 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Smizer GS (Sumilizer GS: acrylic acid 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, manufactured by Sumitomo Chemical), Sumilizer GM ( Sumilizer GM: 2-tert-butyl-4-methyl-6-acrylate (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), vitamin E (produced by Eisai), etc. .
Among these commercially available phenolic antioxidants, Irganox 1010, Irganox 1076, Adekastab AO-60, Adekastab AO-80, and Sumilizer GS are preferred from the viewpoint of imparting thermal stability with the resin.
These may be used alone or in combination of two or more.

  Examples of the phosphorus antioxidant include those classified into phosphites and phosphonites.

  Specific examples of phosphorus-based antioxidants for phosphites include, but are not limited to, for example, tris (2,4-di-t-butylphenyl) phosphite, tris (2,6-di). -T-butylphenyl) phosphite, tris (2,4-di-t-butyl-5-methylphenyl) phosphite, bis (2,4-di-t-butyl-6-methylphenyl) ethyl phosphite, 2,2′-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, cyclic neopentane And tetraylbis (2,6-di-t-butyl-4-methylphenyl) phosphite.

  Commercially available phosphorus-based antioxidants may be used. For example, Irgafos 168 (Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite, manufactured by BASF), Irgafos 12 (Irgafos 12: Tris [2- [ [2,4,8,10-tetra-t-butyldibenzo [d, f] [1,3,2] dioxaphosphin-6-yl] oxy] ethyl] amine (manufactured by BASF), Irgaphos 38 ( Irgafos 38: bis (2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite, manufactured by BASF), Adekastab HP-10 (ADKSTAB HP-10: 2,2′-methylenebis (4,6-di-) tert-butylphenyl) octyl phosphite: manufactured by ADEKA Corporation), ADK STAB PEP24G (A EKASTAB PEP24G: cyclic neopentanetetrayl bis (2,4-di-tert-butylphenyl) phosphite: manufactured by ADEKA Corporation, ADK STAB PEP36 (ADKSTAP PEP36: bis (2,6-di-t-butyl-4) -Methylphenyl) pentaerythritol diphosphite: manufactured by ADEKA Corporation), ADK STAB PEP36A (ADKSTAB PEP36A: bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite: manufactured by ADEKA Corporation) ADK STAB PEP-8 (ADKSTAP PEP-8: Cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl phosphite: manufactured by ADEKA Corporation), Sumilizer GP (Sumil zerGP: (6- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10-tetra-t-butyldibenz [d, f] [1,3 2] Dioxaphosphepine, manufactured by Sumitomo Chemical Co., Ltd.).

  Examples of phosphorus antioxidants for phosphonites include tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butyl-5- Methylphenyl) 4,4′-biphenylenediphosphonite, in particular, as a commercially available product, Hostanox® P-EPQ® (P-EPQ: tetrakis (2,4-di-tert-butylphenyl) 4 , 4′-biphenylenediphosphonite: manufactured by Clariant Co. Ltd., GSY P101 (tetrakis (2,4-di-t-butyl-5methylphenyl) 4,4′-biphenylenediphosphonite: manufactured by Sakai Chemical Co., Ltd.), etc. Is mentioned.

Among the above-mentioned commercially available phosphorous antioxidants, it is preferable to use ADK STAB PEP-36, ADK STAB PEP-36A, SUMILIZER GP, GSYP101, etc. from the viewpoint of the effect of imparting thermal stability with the resin.
These may be used alone or in combination of two or more.

In addition, specific examples of the sulfur-based antioxidant are not limited to the following. For example, 2,4-bis (dodecylthiomethyl) -6-methylphenol (Irganox 1726, manufactured by BASF), Irganox 1520L, manufactured by BASF), 2,2-bis {[3- (dodecylthio) -1-oxopolopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (ADK STAB AO-412S, ADEKA 2,2-bis {[3- (dodecylthio) -1-oxopolopoxy] methyl} propane-1,3-diylbis [3-dodecylthio] propionate] (Cheminox (registered trademark) PLS, manufactured by Chemipro Kasei Co., Ltd.) Di (tridecyl) 3,3′-thiodipropionate (AO-503, manufactured by ADEKA) ) And the like.
Among these commercially available sulfur-based antioxidants, it is preferable to use ADK STAB AO-412S, Cheminox PLS, or the like from the viewpoint of imparting thermal stability with the resin.
These may be used alone or in combination of two or more.

  The content of the antioxidant may be an amount that can achieve the effect of improving the thermal stability, and if the content is excessive, there is a possibility that problems such as bleeding out during processing may occur. The amount 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, still more preferably 0.8 parts by mass or less, more preferably 100 parts by mass or less based on methacrylic resin. More preferably, it is 0.01-0.8 mass part, Most preferably, it is 0.01-0.5 mass part.

-UV absorber-
The methacrylic resin composition of the present embodiment may contain an ultraviolet absorber as necessary in applications such as use as the outermost layer of the polarizing plate protective film.

  Examples of ultraviolet absorbers include, but are not limited to, for example, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, and malons. Examples include acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and the like.

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

Examples of benzotriazine compounds include 2-mono (hydroxyphenyl) -1,3,5-triazine compounds, 2,4-bis (hydroxyphenyl) -1,3,5-triazine compounds, and 2,4,6-tris. (Hydroxyphenyl) -1,3,5-triazine compounds are mentioned, and specifically, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2 , 4-Diphenyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine 2,4-diphenyl- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyv) Nyl) -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- Meto Cyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4) -Propoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy) -4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6-tris ( 2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4 6-Tris ( 2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyethoxyphenyl) -1,3,5-triazine, 2,4 6-tris (2-hydroxy-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-propoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-methoxycarbonylpropyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxycarbonylethyloxyphenyl)- 1,3,5-triazine, 2,4,6-tris (2-hydroxy-4- (1- (2-ethoxyhexyloxy) -1-oxopropan-2-yl Oxy) 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- -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-ethoxyethoxy) Phenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris ( 2-hydroxy-3-methyl-4-propoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-methoxycarbonylpropyloxy) Phenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl) -1,3,5-triazine, 2,4,6- And tris (2-hydroxy-3-methyl-4- (1- (2-ethoxyhexyloxy) -1-oxopropan-2-yloxy) phenyl) -1,3,5-triazine.
Among them, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4 is preferred because it is highly compatible with amorphous thermoplastic resins, particularly acrylic resins, and has excellent absorption characteristics. -(3-alkyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton (“alkyloxy” means a long-chain alkyloxy group such as octyloxy, nonyloxy, decyloxy, etc.) The ultraviolet absorber which has is mentioned.

  As the ultraviolet absorber, in particular, from the viewpoint of compatibility with the resin and volatility at the time of heating, a benzotriazole-based compound and a benzotriazine-based compound are preferable, and the ultraviolet absorber itself suppresses decomposition by heating during extrusion processing. From the viewpoint, a benzotriazine-based compound is preferable.

  These ultraviolet absorbers may be used alone or in combination of two or more.

  An ultraviolet absorber is usually added to absorb ultraviolet light and suppress transmission at 200 to 380 nm, but it is necessary to add a large amount in a thin film or the like, and it is effective only with one kind of ultraviolet absorber. Transmission cannot be suppressed. In order to efficiently suppress the transmission with a small amount, it is preferable to use two types of a compound having an absorption maximum at a wavelength of 200 to 315 nm and a compound having an absorption maximum at a wavelength of 315 to 380 nm. For example, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy] phenol having an absorption maximum of 280 to 300 nm ( ADEKA Corporation, LA-46) and 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) 1,3 having an absorption maximum of 350 to 380 nm , 5-triazine (manufactured by BASF, Tinuvin (registered trademark) 460), hydroxyphenyltriazine-based tinuvin 477 (manufactured by BASF), 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) ) -1,3,5-triazine (made by ADEKA Corporation, LA-F70) is preferably used in combination with at least one selected from the group consisting of:

Further, 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 more preferably 160 ° C. or higher. More preferred.
The ultraviolet absorber preferably has a weight loss rate of 50% or less, more preferably 30% or less, and 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Is more preferably 10% or less, still more preferably 5% or less.

  The blending amount of the ultraviolet absorber is not limited to heat resistance, moist heat resistance, thermal stability, and molding processability, as long as it is an amount that exhibits the effects of the present invention. Since problems such as bleeding out during processing may occur, the amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 2 parts by mass with respect to 100 parts by mass of the methacrylic resin. 5 mass parts or less, More preferably, it is 2 mass parts or less, More preferably, it is 0.01-1.8 mass parts.

-Other additives-
The methacrylic resin composition according to this embodiment may contain other additives as long as the effects of this embodiment are not significantly impaired.
Other additives are not particularly limited, but include, for example, inorganic fillers; pigments such as iron oxides; lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylene bisstearamide.・ Mold release agents: Softeners and plasticizers such as paraffinic process oil, naphthenic process oil, aromatic process oil, paraffin, organic polysiloxane and mineral oil; higher alcohols such as cetyl alcohol and stearyl alcohol; stearic acid monoglyceride Mold release agents such as glycerin higher fatty acid esters such as stearic acid diglyceride; Flame retardants; Antistatic agents; Reinforcing agents such as organic fibers, glass fibers, carbon fibers, metal whiskers; Colorants; Other additives; Etc.

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

- weight-average molecular weight _(Mw RI, Mw _UV) -
In this embodiment, Mw _RI and Mw _UV are used as the weight average molecular weight (Mw).
Here, Mw _RI is a weight average molecular weight obtained using a differential refractive index detector, and Mw _UV is a weight average molecular weight obtained using an ultraviolet-visible absorbance detector at a detection wavelength of 254 nm.

In the methacrylic resin composition of the present embodiment, the polystyrene equivalent weight average molecular weight (Mw _RI ) determined using a differential refractive index detector measured by GPC is in the range of 80,000 to 200,000. Is more preferable, more preferably 80,000 to 170,000, still more preferably 100,000 to 150,000.
When the weight average molecular weight (Mw _RI ) is in this range, it is preferable because the balance between mechanical strength and moldability is excellent.

Furthermore, in the methacrylic resin composition of the present embodiment, the polystyrene-reduced weight average molecular weight (Mw) measured by GPC satisfies the following relationship: 1.1 ≦ Mw _UV / Mw _RI ≦ 2.0
Here, Mw _RI and Mw _UV have the above-mentioned meanings.

Mw _RI can be measured using a differential refractive index detector.
Moreover, Mw _UV can be measured using a UV-visible absorbance detector, and the measurement wavelength at this time is 254 nm suitable for detection of an aromatic group.

In addition, more specifically, Mw _RI and Mw _UV measured by GPC can be measured by the method described in the examples described later.

As described above, the Mw _UV / Mw _RI in the methacrylic resin composition of the present embodiment is in the range of 1.1 to 2.0, preferably in the range of 1.1 to 1.5, and more preferably. Is in the range of 1.1 to 1.4.
When in this range, when forming a functional layer on at least one of the front and back surfaces of a film prepared using this composition, the adhesion is further improved without deteriorating the optical properties of the base film. In particular, it is preferable because stable adhesion can be maintained even in use in a relatively harsh environment.

  Here, the effect of the present invention will be described.

In the preparation of the methacrylic resin having a main chain in the ring structure, if often, the structural unit having an aromatic group with ultraviolet-visible absorption, for control of optical properties such as improvement and photoelastic coefficient of the heat-resistant resin In addition, it is introduced into the resin as its copolymer component.
For example, Patent Document 4 described above proposes the use of a methacrylic resin in which a styrene structural unit is introduced into a copolymer at a relatively high content of 10 to 70% by mass.
However, the introduction of structural units having aromatic groups can also affect the solubility parameters of the resin itself. Specifically, the introduction of a structural unit having an aromatic group, for example, the introduction of a structural unit derived from an aromatic vinyl monomer reduces the glass transition temperature, which is an indicator of the heat resistance of the resin, and functions as a film. When the organic solvent containing composition used for laminating | stacking a layer is applied, it may have the fault that the optical characteristic of resin falls.

  Here, in GPC measurement, by using a differential refractive index detector and a visible ultraviolet absorption detector in combination, variation in content of structural units having a chemical structure having an aromatic group for each resin of each molecular weight. In this embodiment, in the methacrylic resin composition, by controlling the composition distribution of structural units having an aromatic group having ultraviolet-visible absorption, relatively harsh use conditions can be evaluated. The present inventors have found that an optical film including a functional layer that can maintain stable adhesion even underneath can be provided.

Specifically, if an ultraviolet-visible absorbance detector with a measurement wavelength of 254 nm is used, the weight average molecular weight (Mw _UV ) of a resin containing a structural unit having an aromatic group having absorption at a wavelength of 254 nm is determined as the structural unit. Can do.
In the methacrylic resin composition of the present embodiment, in the methacrylic resin contained in the composition and at least one of the other thermoplastic resins added as necessary, the above-described ultraviolet-visible absorption. It is preferable to include a specific functional group, and it is particularly preferable to include the above-described aromatic group.

  In the methacrylic resin composition of the present embodiment, in at least one of the methacrylic resin contained in the composition and other thermoplastic resins added as necessary, an aromatic vinyl-based resin is used. It is preferable to include a structural unit derived from a monomer or a structural unit derived from an N-arylmaleimide monomer.

-Glass transition temperature-
The glass transition temperature (Tg) of the methacrylic resin composition in this embodiment is more than 120 ° C. and 160 ° C. or less.
If the glass transition temperature (Tg) of the methacrylic resin composition exceeds 120 ° C., necessary and sufficient heat resistance can be obtained more easily as a recent lens molded body and a film molded body optical film for a liquid crystal display.
The glass transition temperature (Tg) is more preferably 125 ° C. or higher, and still more preferably 130 ° C. or higher, from the viewpoint of dimensional stability under the use environment temperature.
On the other hand, when the glass transition temperature (Tg) of the methacrylic resin composition exceeds 160 ° C., the temperature at the time of melt processing must be set to a considerably high temperature, which tends to cause thermal decomposition of the resin, etc. It may be difficult to obtain a good product.
The glass transition temperature (Tg) is preferably 150 ° C. or lower for the reasons described above.
The glass transition temperature (Tg) can be determined by measuring in accordance with JIS-K7121. Specifically, it can measure using the method described in the Example mentioned later.

-Methanol-soluble matter-
The ratio of the amount of methanol-soluble component of the methacrylic resin composition in the present embodiment to 100% by mass of the total amount of methanol-soluble component and methanol-insoluble component is 5% by mass or less, preferably 4 0.5% or less, more preferably 4% by mass or less, still more preferably 3.5% by mass or less, preferably 3% by mass or less, and more preferably 2.5% by mass or less. .
By making the ratio of the amount of the soluble component 5% by mass or less, the adhesion is further improved when the functional layer is formed on the film surface (at least one of the front and back surfaces) prepared using this composition. In particular, stable adhesion can be maintained even when used in a relatively severe environment.
The methanol-soluble and methanol-insoluble components are obtained by reprecipitation by dropping the solution into a large excess of methanol after the methacrylic resin composition is made into a chloroform solution, and then separating the filtrate and the filtrate. These are obtained by drying each, and specifically, can be obtained by the methods described in the Examples below.
The method for adjusting the proportion of methanol-soluble matter so as to satisfy the above range is not particularly limited. For example, the method for adding a monomer or the method for adding a polymerization initiator in polymerization is controlled. The method of suppressing the production | generation of an oligomer and a low molecular weight body is mentioned.
The methanol-soluble component of the methacrylic resin composition of the present embodiment includes, for example, an unreacted monomer component, an oligomer component such as a dimer or trimer, and a weight average molecular weight of 1 , A component having a low molecular weight component of about 1,000 to 15,000 and a composition soluble in methanol at room temperature.

-Photoelastic coefficient-
The absolute value of the photoelastic coefficient C _R of the methacrylic resin composition containing a structural unit (X) having a main chain in the ring structure of the present embodiment is preferably 3.0 × 10 ^-12 Pa ^-1 or less 2.0 × 10 ⁻¹² Pa ⁻¹ or less, more preferably 1.0 × 10 ⁻¹² Pa ⁻¹ or less.
The photoelastic coefficient is described in various documents (see, for example, Chemical Review, No. 39, 1998 (published by the Academic Publishing Center)) and is defined by the following formulas (ia) and (ib). It is. As the value of photoelastic coefficient C _R is close to zero, it can be seen that change in birefringence due to an external force is small.
C _R = | Δn | / σ _R (i−a)
| Δn | = | nx−ny | (i−b)
(In the formula, _CR is a photoelastic coefficient, σ _R is an extension stress, | Δn | is an absolute value of birefringence, nx is a refractive index in the extension direction, and ny is a direction perpendicular to the extension direction in the plane. The refractive index of each is shown.)
If the absolute value of the photoelastic coefficient C _R of the methacrylic resin composition of the present embodiment is 3.0 × 10 ^-12 Pa ^-1 or less, be used in a liquid crystal display device with a film, a retardation unevenness occurs It is possible to suppress or prevent the contrast at the periphery of the display screen from decreasing or the occurrence of light leakage.
Note that the photoelastic coefficient C _R, specifically, can be determined by the method described in Examples described later.

(Method for producing methacrylic resin composition)
The method for producing the methacrylic resin composition of the present embodiment is not particularly limited as long as a composition satisfying the requirements of the present invention can be obtained.
When the melt extrusion method is employed as a method for preparing the composition, it is preferable to employ a method of preparing the composition while using a vented extruder and removing residual volatile components as much as possible.

Further, when the methacrylic resin composition of the present embodiment is used for a film application or the like, for the purpose of reducing foreign matter, a polymerization reaction step, a liquid-liquid separation step, a liquid-solid separation step, a devolatilization step, granulation In one or more of the process and the molding process, for example, a sintered filter having a filtration accuracy of 1.5 to 20 μm, a pleated filter, a leaf disk type polymer filter and the like are added to the filtration device and prepared. It is also a preferable method.
Regardless of which method is selected, it is preferable to reduce the oxygen and moisture as much as possible when producing the methacrylic resin composition.
For example, the dissolved oxygen concentration in the polymerization solution in solution polymerization is less than 300 ppm in the polymerization step, and in the preparation method using an extruder or the like, the oxygen concentration in the extruder is less than 1% by volume. It is preferable to be less than 0.8% by volume.
It is recommended that the water content of the methacrylic resin is adjusted to preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less.

For example, when adopting a manufacturing method using an extruder, the pelletized methacrylic resin as a raw material is heated under reduced pressure or dehumidified air and sufficiently dried in advance to remove moisture as much as possible. And preferably used.
At that time, when various antioxidants and additives described later are blended, it is preferable to blend these various antioxidants and additives themselves after sufficiently reducing the amount of water contained therein.
Furthermore, in order to reduce oxygen contamination in the extruder as much as possible and prevent oxidation of the composition in the molten state, an inert gas such as nitrogen gas is allowed to flow into the extruder and a vented extruder is used. It is preferable to carry out while evacuating under reduced pressure.
As drying temperature of the raw material in that case, 40-120 degreeC is preferable, More preferably, it is the range of 70-100 degreeC.
There is no particular limitation on the degree of decompression, and the degree of decompression may be selected as appropriate.

Using an extruder, the methacrylic resin composition melt-kneaded and brought into a molten state is melt-extruded from a porous die and pelletized.
In this case, examples of the granulation method that can be used include an aerial hot cut method, a watering hot cut method, a cold cut method, an underwater strand cut method, an underwater cut method, and the like.

Among these, the underwater strand cut method is generally more preferable from the viewpoint of productivity and granulator cost.
In that case, the molten resin temperature should be lowered as much as possible, the residence time from the perforated die outlet to the cooling water surface should be minimized, and the cooling water temperature should be as high as possible. It is more preferable to perform granulation.
For example, the molten resin temperature is preferably 240 to 300 ° C, more preferably 250 to 290 ° C, and the residence time from the porous die outlet to the cooling water surface is preferably within 5 seconds, more preferably within 3 seconds. The temperature of the cooling water is preferably 30 to 80 ° C, more preferably 40 to 60 ° C.

  In the present embodiment, from the viewpoint of obtaining a suitable composition distribution characteristic in the resin composition, this embodiment is carried out by using two or more methacrylic resins having the same type of ring structure in the main chain and having a weight average molecular weight and a molecular weight distribution. It is preferable to appropriately select the proportion of the structural units derived from the respective monomers, the weight average molecular weight and the molecular weight distribution, and the mixing ratio thereof as long as the characteristics defined by the form are satisfied.

  As described above, from the viewpoint of obtaining suitable composition distribution characteristics in the resin composition, the structural units having the same kind of ring structure in the main chain and having an aromatic ring substituent are included at different ratios, and different weight averages. As long as two or more kinds of methacrylic resins having a molecular weight and a molecular weight distribution are used and satisfy the characteristics defined in this embodiment, the proportion of the structural unit derived from the monomer in each type of resin, the weight average molecular weight, and It is preferable to appropriately select the molecular weight distribution and the mixing ratio of these types of resins.

  In the present embodiment, the method for preparing a resin composition by mixing two or more methacrylic resins is not particularly limited, but a method of melt kneading using an extruder, or the like can be employed.

In addition, the details of the two kinds of methacrylic resins, and the weight average molecular weight (Mw _RI ), the molecular weight distribution (Mw / Mn) _RI , and the mixing ratio regarding the high molecular weight component and the low molecular weight component of the two methacrylic resins The details may be as described above.
In particular, when the molecular weight distribution of the high molecular weight component (Mw / Mn) _RI is greater than the low molecular weight distribution of molecular weight component (Mw / Mn) _RI, homogeneity is increased more of the resin composition, stabilized resin composition excellent quality And can be produced.

  As described above, the method of mixing two or more methacrylic resins is not particularly limited, and a method of performing a post-treatment by mixing a solution containing two or more polymers in a liquid phase, or after granulation A method of mixing using a melt-kneading apparatus such as an extruder can be employed. When a methacrylic resin having a particularly high molecular weight is used, a solution containing two or more kinds of polymers is mixed in the liquid phase. A method of performing post-treatment is preferred.

(Optical film)
The resin composition of the present embodiment is a known method such as injection molding, sheet molding, blow molding, injection blow molding, inflation film molding, T-die film molding, press molding, extrusion molding, foam molding, cast molding, By applying a secondary processing molding method such as pressure molding or vacuum molding, a molded body can be obtained.
Especially, it is suitable to form a sheet | seat and a film using sheet | seat shaping | molding, inflation film shaping | molding, T-die film shaping | molding, and extrusion molding, and to set it as an optical sheet or an optical film.

For example, a method for producing a pre-stretched film (unstretched film) and a stretched film using the methacrylic resin composition of the present embodiment will be described below.
As such a method, for example, a raw material resin is supplied to a single-screw or twin-screw extruder, melted and kneaded, and then a sheet extruded from a T die is guided onto a cast roll and solidified. Subsequently, longitudinal uniaxial stretching is performed in a mechanical flow direction using a pair of rolls having different peripheral speeds, or horizontal uniaxial stretching is performed in a direction orthogonal to the mechanical flow direction (TD direction). Examples include uniaxial stretching; sequential biaxial stretching using roll stretching and tenter stretching, simultaneous biaxial stretching by tenter stretching, biaxial stretching by tubular stretching, inflation stretching, biaxial stretching by tenter method sequential biaxial stretching, etc. it can. Among these, since the characteristics of the methacrylic resin composition of the present embodiment can be expressed most, sequential biaxial stretching composed of roll stretching and tenter stretching is preferable.

  The final draw ratio can be determined from the heat shrinkage rate of the obtained molded / stretched body. The draw ratio is preferably 0.1 to 400%, more preferably 10 to 400%, and still more preferably 50 to 350% in at least one direction. When it is less than the lower limit, the bending strength tends to be insufficient, and when it exceeds the upper limit, breakage and tear frequently occur in the film production process, and the film cannot be produced continuously and stably. By designing in this range, a stretched molded article that is preferable from the viewpoint of birefringence, heat resistance, and strength can be obtained.

The stretching temperature is preferably Tg-30 ° C to Tg + 50 ° C. Here, Tg (glass transition temperature) refers to a value for a resin composition used for preparing a film.
In the obtained film, in order to obtain good film thickness uniformity, the lower limit of the stretching temperature is preferably (Tg-20 ° C) or more, more preferably (Tg-10 ° C) or more, and further preferably Tg or more. Particularly preferred is (Tg + 5 ° C.) or more, and particularly preferred is (Tg + 7 ° C.) or more. The upper limit of the stretching temperature is preferably (Tg + 45 ° C.) or less, more preferably (Tg + 40 ° C.) or less.
In addition, when using the film of this embodiment as an optical film, in order to stabilize the optical isotropy and mechanical characteristic, it is preferable to perform heat processing (annealing) etc. after an extending | stretching process. The heat treatment conditions may be appropriately selected in the same manner as the heat treatment conditions performed on a conventionally known stretched film, and are not particularly limited.

  Although the thickness as an optical film does not have a restriction | limiting in particular, For example, it is 1-250 micrometers, and 10-100 micrometers is preferable.

The use of the molded article such as a film and a sheet is not particularly limited, but for example, a light guide plate, a diffusion plate, a 1/1 used for a display such as a liquid crystal display, a plasma display, an organic EL display, a field emission display, and a rear projection television. 4 wavelength plate, 1/2 wavelength plate, polarizer protective film, viewing angle compensation film, retardation film such as liquid crystal optical compensation film, display front plate, display substrate, lens, touch panel, optical waveguide, etc. It can use suitably for the transparent base | substrate etc. which are used for a solar cell.
Of these, a functional layer is often used on the surface, and is preferably used for an optical film and an optical sheet. Especially, it is preferably used for a retardation film such as a polarizer protective film, a viewing angle compensation film, and a liquid crystal optical compensation film. Can be used.

(Optical parts)
The functional layer applied to the surface is not particularly limited, and examples thereof include a hard coat layer, an antiglare (non-glare) layer, an antireflection layer, a light scattering layer, an antistatic layer, and an ultraviolet shielding layer. These can be combined and used.
Although there is no restriction | limiting in particular as the thickness of these functional layers, Usually, it uses in the range of 0.01-10 micrometers.
Examples of the hard coat layer applied to the surface include a silicone-based curable resin, an organic polymer composite inorganic fine particle-containing curable resin, an acrylate such as urethane acrylate, epoxy acrylate, and polyfunctional acrylate, and a photopolymerization initiator. The coating solution dissolved or dispersed in is coated on a film or sheet obtained from the methacrylic resin composition of the present embodiment by a conventionally known coating method, dried and photocured.
Before applying the hard coat layer, in order to improve adhesion, for example, an easy-adhesion layer, a primer layer, an anchor layer, etc. containing inorganic fine particles in the composition are provided in advance, and then the hard coat layer is formed. Methods can also be used.
The antiglare layer to be applied to the surface is formed by converting fine particles of silica, melamine resin, acrylic resin, etc. into ink, applying it on other functional layers with a conventionally known application method, and heat or photocuring it. Let
Antireflective layers applied to the surface include those made of inorganic thin films such as metal oxides, fluorides, silicides, borides, nitrides and sulfides, and resins having different refractive indexes such as acrylic resins and fluororesins. Can be used, and a laminate in which thin layers containing composite fine particles of an inorganic compound and an organic compound are laminated can also be used.

  Hereinafter, the contents of the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, this invention is not limited to the following Example.

(1. Analysis of structural units)
Unless otherwise specified in each production example described below, the structural unit of the methacrylic resin produced in the production example described later was identified by ¹ H-NMR measurement and ¹³ C-NMR measurement, and the abundance thereof was calculated. The measurement conditions for ¹ H-NMR measurement and ¹³ C-NMR measurement are as follows.
・ Measurement equipment: DPX-400 manufactured by Blue Car Co., Ltd.
Measurement solvent: CDCl3 or d6-DMSO
・ Measurement temperature: 40 ℃
When the ring structure of the methacrylic resin is a lactone ring structure, it is confirmed by the method described in JP 2001-151814 A. When the ring structure of the methacrylic resin is a glutarimide ring structure, It confirmed by the method of international publication 2012/114718.

(2. Molecular weight and molecular weight distribution)
Weight average molecular weight (Mw _RI ) and weight average molecular weight (Mw _RI ), number average molecular weight (Mn _UV ) of methacrylic resins produced in the production examples described later, and methacrylic resin compositions produced in the examples and comparative examples described later. ) And number average molecular weight (Mn _UV ) were measured by the following apparatus and conditions.
-Measuring apparatus: Tosoh Corporation gel permeation chromatography (HLC-8320GPC)
·Measurement condition:
Column: One TSK guard column SuperH-H, two TSK gel Super HM-M, and one TSK gel Super H 2500 were connected in series in this order. Column temperature: 40 ° C
Developing solvent: Tetrahydrofuran, Flow rate: 0.6 mL / min, 0.16 g / L of 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard.
First detector: RI detector (differential refractive index detector), detection sensitivity: 3.0 mV / min Second detector: UV detector (UV-visible absorbance detector), UV-8020 (manufactured by Tosoh Corporation), detection Wavelength: 254nm
Sample: 0.02 g of methacrylic resin or methacrylic resin composition in 20 mL of tetrahydrofuran. Injection volume: 10 μL
Standard sample for calibration curve: The following nine standard polystyrenes (manufactured by Tosoh Corporation, TSK Standard) with known monodisperse weight peak molecular weights and different molecular weights were used.
Weight peak molecular weight (Mp)
Standard sample 1 2,890,000
Standard sample 2 706,000
Standard sample 3 427,000
Standard sample 4 195,900
Standard sample 5 37,900
Standard sample 6 17,400
Standard sample 7 9,100
Standard sample 8 2,630
Standard sample 9 1,010
Under the above conditions, the RI detection intensity and the UV detection intensity with respect to the elution time of the methacrylic resin or the methacrylic resin composition were measured.
Based on each calibration curve obtained by the measurement of the standard sample for the calibration curve, the weight average molecular weight (Mw _RI and Mw _UV ) and the number average molecular weight (Mn _RI and Mn) of the methacrylic resin and the methacrylic resin composition. _UV ) was determined, and the value was used to determine the molecular weight distribution ((Mw / Mn) _RI and (Mw / Mn) _UV ).

(3. Glass transition temperature)
Based on JIS-K7121, the glass transition temperature (Tg) (degreeC) of the methacrylic resin composition was measured.
First, 4 pieces (about 4 places) of about 10 mg each were cut out as test pieces from a sample that was conditioned (left at 23 ° C. for 1 week) under standard conditions (23 ° C., 65% RH).
Next, a differential scanning calorimeter (Diamond DSC manufactured by PerkinElmer Japan Co., Ltd.) was used under the condition of a nitrogen gas flow rate of 25 mL / min, where the temperature rose from room temperature (23 ° C.) to 200 ° C. at 10 ° C./min. Temperature (primary temperature increase), held at 200 ° C. for 5 minutes to completely melt the sample, then cooled to 10 ° C./minute from 200 ° C. to 40 ° C., held at 40 ° C. for 5 minutes, Of the DSC curve drawn during the temperature rise (secondary temperature rise) again under the above temperature rise conditions, the stepwise change partial curve at the time of the secondary temperature rise and the respective base line extension lines are equidistant in the vertical axis direction. The intersection (intermediate glass transition temperature) with a certain straight line was measured as the glass transition temperature (Tg) (° C.). Four points were measured per sample, and the arithmetic average of four points (rounded off after the decimal point) was taken as the measured value.

(4. Methanol-soluble fraction)
After 5 g of the methacrylic resin composition obtained in Examples and Comparative Examples was dissolved in 100 mL of chloroform, the solution was put into a dropping funnel and stirred for about 1 hour in 1 L of methanol stirred with a stir bar. The solution was added dropwise to perform reprecipitation. After dropping the whole amount, the solution was allowed to stand for 1 hour, and then suction filtration was performed using a membrane filter (T05A090C, manufactured by Advantech Toyo Co., Ltd.) as a filter.
The filtrate was vacuum-dried at 60 ° C. for 16 hours to make methanol insoluble. In addition, the filtrate may be left in the eggplant-shaped flask after the solvent is removed using a rotary evaporator at a bath temperature of 40 ° C. and gradually lowering the vacuum from the initial setting of 390 Torr to 30 Torr. Soluble was recovered and used as methanol soluble.
Each of the mass of the methanol-insoluble part and the mass of the methanol-soluble part is weighed, and the ratio of the amount of methanol-soluble part to the total amount (100% by mass) of the amount of methanol-soluble part and the amount of methanol-insoluble part (mass) %) (Methanol soluble fraction) was calculated.

(Measurement of 5. photoelastic coefficient _{C R)}
The methacrylic resin compositions obtained in Examples and Comparative Examples were used as measurement samples by using a vacuum compression molding machine as a press film. As specific sample preparation conditions, using a vacuum compression molding machine (SFV-30 manufactured by Shinfuji Metal Industry Co., Ltd.), preheating at 260 ° C. under reduced pressure (about 10 kPa) for 10 minutes, the resin composition was heated to 260 ° C. Then, after compressing at about 10 MPa for 5 minutes and releasing the reduced pressure and the press pressure, it was transferred to a cooling compression molding machine and solidified by cooling. The obtained press film was cured for 24 hours or more in a constant temperature and humidity chamber adjusted to 23 ° C. and a humidity of 60%, and then a test specimen (thickness: about 150 μm, width: 6 mm) was cut out.
The photoelastic coefficient C _R (Pa ⁻¹ ) was measured using a birefringence measuring apparatus described in detail in Polymer Engineering and Science 1999, 39, 2349-2357.
The film-shaped test piece was similarly arrange | positioned so that it might become 50 mm between chuck | zippers on the film tension apparatus (made by Imoto Seisakusho) installed in the constant temperature and humidity chamber. Next, the apparatus was arranged so that the laser beam path of the birefringence measuring apparatus (manufactured by Otsuka Electronics, RETS-100) was positioned at the center of the film, and the strain rate was 50% / min (between chucks: 50 mm, chuck moving speed: The birefringence of the test piece was measured while applying an extensional stress at 5 mm / min.
From the relationship between the absolute value of birefringence (| Δn |) and the tensile stress (σ _R ) obtained from the measurement, the slope of the straight line is obtained by least square approximation, and the photoelastic coefficient (C _R ) (Pa ⁻¹ ) is obtained. Calculated. For the calculation, data with an extensional stress between 2.5 MPa ≦ σ _R ≦ 10 MPa was used.
C _R = | Δn | / σ _R
Here, the absolute value (| Δn |) of birefringence is a value shown below.
| Δn | = | nx−ny |
(Nx: refractive index in the stretching direction, ny: refractive index in the direction perpendicular to the stretching direction in the plane)

(6. Adhesion evaluation)
((Preparation of stretched film))
From the methacrylic resin compositions obtained in Examples and Comparative Examples described later, a 50 mmφ single-screw extrusion in which a filter for resin filtration (leaf filter, manufactured by Nagase Sangyo) and a T-die having a width of 480 mm are installed at the tip of the extruder. A film was prepared using a machine.
The film forming conditions at that time were as follows: extruder set temperature: 260 ° C., T die set temperature: 255 ° C., discharge rate: 8 kg / hour, cooling roll set temperature: (glass transition temperature−10 ° C.), film thickness 250 μm An unstretched film was obtained.

Continuously, longitudinal stretching is performed on the unstretched film using a roll stretching apparatus including a pair of preheating rolls, a pair of stretching rolls, an infrared heater installed between the stretching rolls, and a pair of transport rolls in this order. It was.
At that time, as the temperature of each roll, based on the glass transition temperature of the resin composition used for evaluation, preheating roll temperature: (glass transition temperature + 10 ° C.), low-speed drawing roll temperature: (glass transition temperature + 30 ° C.) High-speed-side stretching roll temperature: (glass transition temperature + 10 ° C.), transport roll temperature: (glass transition temperature−10 ° C.). The distance between the pair of stretching rolls was 200 mm. Under this temperature condition, the difference in peripheral speed between the high speed side and low speed side stretching rolls was 2.5 times.

Continuously with the above-described longitudinal stretching, the stretched film was subjected to transverse stretching using a tenter-type transverse stretching machine. The temperature of each part inside the tenter device is based on the glass transition temperature of the resin composition used for evaluation, respectively, preheating part: glass transition temperature, stretching part: (glass transition temperature + 10 ° C.), heat treatment part: glass transition temperature It was.
Under these conditions, the film was stretched 2.5 times by transverse stretching to obtain a biaxially stretched film having an average thickness of 40 microns.

((Preparation of stretched film with functional layer laminated as an example of hard coat layer))
--- Preparation of hard coat solution--
In a mixed solvent composed of 70 parts by mass of methyl isobutyl ketone and 30 parts by mass of isopropyl alcohol, 35 parts by mass of urethane acrylate resin (manufactured by Nippon Kayaku, DPHA-40H), photo radical polymerization initiator (manufactured by BASF, Irgacure 184) 1.75 parts by mass were added and dissolved to prepare a hard coat solution.
--Formation of hard coat layer-
The stretched film obtained in each Example and Comparative Example was cut into A4 size, and the hard coat solution prepared above was applied onto the surface using a bar coater # 6. The coated film is held for 10 minutes and then dried at 80 ° C. for 2 minutes. Thereafter, the film is irradiated with ultraviolet light having an integrated light quantity of 300 mJ / cm ² with a high-pressure mercury lamp to cure the coating film. A hard coat layer having a thickness of 6 microns was formed thereon.

((6-1. Performance evaluation 1 (initial adhesion)))
The film with the hard coat layer provided on the surface as described above was conditioned for 6 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and then the adhesion test shown below was performed. The adhesion to the hard coat layer was evaluated.
A cross cut test was performed in accordance with JIS K5400 3.5. Specifically, a 1 mm square grid cut was made with a sharp blade on the hard coat layer surface, and a cellophane tape having a width of 25 mm according to JIS Z1522 was adhered with a wooden spatula, and then the cellophane tape was peeled off. . And the number of remaining squares was counted visually.
Similarly, the above procedure was repeated a total of 5 times, the average value of the number of cells remaining was calculated, and the adhesion of the film to the hard coat layer was evaluated based on this average value.
“80” when 80 to 100 grids remain, “Δ” when 40 to 79 grids remain, “X” when 39 or less grids remain. As evaluated.

((6-2. Performance Evaluation 2 (High Temperature Durability)))
The film provided with the hard coat layer on the surface obtained as described above was allowed to stand for 1000 hours in an environment at a test temperature of 95 ° C., and then conditioned for 6 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50%. Later, an adhesion test was performed by the method shown in Performance Evaluation 1 and evaluated in the same manner.

((6-3. Performance evaluation 3 (high temperature / high humidity durability)))
The film provided with the hard coat layer on the surface obtained as described above was allowed to stand for 1000 hours in an environment with a test temperature of 80 ° C. and a relative humidity of 90%, and then under conditions of a temperature of 23 ° C. and a relative humidity of 50%, After adjusting the humidity for 6 hours, an adhesion test was carried out by the method shown in Performance Evaluation 1 and evaluated in the same manner.

[material]
It shows below about the raw material used in the Example and comparative example which are mentioned later.
[[Monomer]]
・ Methyl methacrylate: manufactured by Asahi Kasei Chemicals Corporation ・ N-phenylmaleimide (phMI): manufactured by Nippon Shokubai Co., Ltd. ・ N-cyclohexylmaleimide (chMI): manufactured by Nippon Shokubai Co., Ltd. ・ Methyl 2- (hydroxymethyl) acrylate (MHMA) : Combi Block s, Inc. [[antioxidant]]
・ Irganox 1010 (manufactured by BASF)
・ ADK STAB PEP36 (manufactured by ADEKA)
・ ADK STAB AO-412S (manufactured by ADEKA)

[Production Example 1-1]
Methyl methacrylate (hereinafter referred to as “MMA”) 146.0 kg, N-phenylmaleimide 4.0 kg (hereinafter referred to as “phMI”), N-cyclohexylmaleimide (hereinafter referred to as “chMI”) 32.5 kg, chain Weighed 0.80 kg of n-octyl mercaptan as a transfer agent and 147.0 kg of meta-xylene (hereinafter referred to as “mXy”), and placed it in a 1.25 m ³ reactor equipped with a temperature control device by a jacket and a stirring blade. The mixture was stirred and a mixed monomer solution was obtained.
Next, 271.4 kg of MMA, 7.5 kg of phMI, 60.3 kg of chMI, and 273.0 kg of mXy were weighed, added to tank 1 and stirred to obtain a mixed monomer solution for addition. Further, MMA 58.0 kg was weighed in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 95 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.35 kg of t-butylperoxyisopropyl monocarbonate was dissolved in 4.65 kg of mXy was obtained from (1) to (5). It added by profile and superposed | polymerized.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 124 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, a monomer mixture for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Then, 3 hours after the start of polymerization, MMA was added from tank 2 at a rate of 116 kg / hour over 30 minutes.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus internal temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr. The polymer after devolatilization was pressurized with a gear pump, extruded from a strand die, cooled with water, and pelletized to obtain a methacrylic resin polymer (1-1) having a ring structure in the main chain.
When the composition of the obtained pellet-shaped polymer (1-1) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 80.3% by mass, 1.9% by mass, and 17 respectively. It was 8 mass%. The weight average molecular weight (Mw _RI ) was 95,000, and the molecular weight distribution (Mw / Mn) _RI was 1.85.

[Production Example 1-2]
MMA 146.0 kg, phMI 28.5 kg, chMI 8.0 kg, chain transfer agent n-octyl mercaptan 0.21 kg, methyl isobutyl ketone (hereinafter referred to as “MIBK”) 147.0 kg, weighed by jacket Were added to a 1.25 m ³ reactor equipped with a stirring blade and stirred to obtain a mixed monomer solution.
Next, 271.4 kg of MMA, 52.9 kg of phMI, 14.9 kg of chMI, and 273.0 kg of MIBK were weighed and added to the tank 1 and stirred to obtain a mixed monomer solution for addition. Further, MMA 58.0 kg was weighed in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 100 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.54 kg of 1,1-di (t-butylperoxy) cyclohexane was dissolved in 4.65 kg of MIBK (1) It added by the profile of (5), and superposition | polymerization was performed.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 110 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, a monomer mixture for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Then, 3 hours after the start of polymerization, MMA was added from tank 2 at a rate of 116 kg / hour over 30 minutes.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus internal temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr. The devolatilized polymer was pressurized with a gear pump, extruded from a strand die, cooled with water, and pelletized to obtain a methacrylic resin polymer (1-2) having a ring structure in the main chain.
When the composition of the obtained polymer (1-2) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 82.0% by mass, 14.1% by mass, and 3.9% by mass, respectively. %Met. Moreover, the weight average molecular weight (Mw _RI ) was 237,000, and the molecular weight distribution (Mw / Mn) _RI was 2.3.

[Production Example 1-3]
MMA 146.0 kg, phMI 14.6 kg, chMI 22.0 kg, chain transfer agent n-octyl mercaptan 0.21 kg, mXy 147.0 kg, 1.25 m ³ reaction equipped with jacket temperature controller and stirring blade The mixture was stirred in a container to obtain a mixed monomer solution.
Next, 276.5 kg of MMA, 11.8 kg of phMI, 40.9 kg of chMI, 10.0 kg of styrene, and 265.0 kg of mXy were weighed and added to the tank 1 and stirred to obtain a mixed monomer solution (1) for addition. Furthermore, a mixed monomer solution (2) for addition consisting of 48.0 kg of MMA and 10.0 kg of styrene was prepared in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 124 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.35 kg of t-butylperoxyisopropyl monocarbonate was dissolved in 4.65 kg of mXy was obtained from (1) to (5). It added by profile and superposed | polymerized.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 124 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, the additional monomer solution (1) for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Then, 2 hours after the start of the polymerization, the additional monomer solution (2) for addition was added from the tank 2 at an addition rate of 116 kg / hour over 30 minutes.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Into this polymerization solution, 0.2 part by mass of Irganox 1010 was added with stirring with respect to 100 parts by mass of the polymer contained in the solution.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus internal temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr. The polymer after devolatilization was pressurized with a gear pump, extruded from a strand die, cooled with water, pelletized, and a composition (1-3) containing a methacrylic resin polymer having a ring structure in the main chain was obtained. .
When the composition in the obtained pellet-shaped composition (1-3) was confirmed, the structural units derived from MMA, phMI, chMI, and styrene monomers were 81.1% by mass and 4.6% by mass, respectively. 10.8% by mass and 3.5% by mass. The weight average molecular weight (Mw _RI ) was 149,000, and the molecular weight distribution (Mw / Mn) _RI was 2.0.

[Production Example 1-4]
MMA 163.0 kg, phMI 8.1 kg, chMI 11.6 kg, chain transfer agent n-octyl mercaptan 0.21 kg, methyl isobutyl ketone (hereinafter referred to as MIBK) 147.0 kg, weighed by a jacket temperature control device and stirring blade Was added to a reactor of 1.25 m ³ and stirred to obtain a mixed monomer solution.
Next, 302.6 kg of MMA, 15.1 kg of phMI, 21.5 kg of chMI, and 273.0 kg of MIBK were weighed, added to tank 1, and stirred to obtain a mixed monomer solution for addition. Further, MMA 58.0 kg was weighed in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 100 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.54 kg of 1,1-di (t-butylperoxy) cyclohexane was dissolved in 4.65 kg of MIBK (1) It added by the profile of (5), and superposition | polymerization was performed.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 110 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, a monomer mixture for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Then, 3 hours after the start of polymerization, MMA was added from tank 2 at a rate of 116 kg / hour over 30 minutes.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus internal temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr. The devolatilized polymer was pressurized with a gear pump, extruded from a strand die, cooled with water, pelletized, and a methacrylic resin polymer (1-4) having a ring structure in the main chain was obtained.
When the composition of the obtained polymer (1-4) was confirmed, structural units derived from MMA, phMI, and chMI monomers were 90.3% by mass, 4.0% by mass, and 5.7% by mass, respectively. %Met. Moreover, the weight average molecular weight (Mw _RI ) was 225,000, and the molecular weight distribution (Mw / Mn) _RI was 2.8.

[Production Example 1-5]
MMA 108.1 kg, phMI 32.1 kg, chMI 42.4 kg, chain transfer agent n-octyl mercaptan 0.21 kg, MIBK 147.0 kg, 1.25 m ³ reaction equipped with jacket temperature controller and stirring blade The mixture was added to the vessel and stirred to obtain a mixed monomer solution.
Next, 201 kg of MMA, 59.5 kg of phMI, 78.8 kg of chMI, and 273.0 kg of MIBK were weighed and added to the tank 1 and stirred to obtain a mixed monomer solution for addition. Further, MMA 58.0 kg was weighed in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 100 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.54 kg of 1,1-di (t-butylperoxy) cyclohexane was dissolved in 4.65 kg of MIBK (1) It added by the profile of (5), and superposition | polymerization was performed.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 110 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, a monomer mixture for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Then, 3 hours after the start of polymerization, MMA was added from tank 2 at a rate of 116 kg / hour over 30 minutes.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr. After cooling with water, it was pelletized to obtain a methacrylic resin polymer (1-5) having a ring structure in the main chain.
When the composition of the obtained polymer (1-5) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 63.3 mass%, 15.8 mass%, and 20.9 mass%, respectively. %Met. The weight average molecular weight (Mw _RI ) was 229,000, and the molecular weight distribution (Mw / Mn) _RI was 2.3.

[Production Example 1-6]
MMA146.0kg, phMI28.5kg, chMI8.0kg, chain transfer agent n-octylmercaptan 0.08kg, methylisobutylketone (hereinafter referred to as MIBK) 147.0kg, temperature control device with a jacket and stirring blade Was added to a reactor of 1.25 m ³ and stirred to obtain a mixed monomer solution.
Next, 271.4 kg of MMA, 52.9 kg of phMI, 14.9 kg of chMI, and 273.0 kg of MIBK were weighed and added to the tank 1 and stirred to obtain a mixed monomer solution for addition. Furthermore, 28.0 kg of MMA and 30.0 kg of styrene were weighed in the tank 2 and mixed by stirring to obtain a monomer mixed solution.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, the temperature inside the reactor was raised to 100 ° C. while stirring at 50 rpm, and a polymerization initiator solution in which 0.54 kg of 1,1-di (t-butylperoxy) cyclohexane was dissolved in 4.65 kg of MIBK (1) Polymerization was carried out by adding in the profile of (5).
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 3.5 hours: Feed rate 1.0 kg / hour (3) 3.5 to 4.5 hours: Feed rate 0.5 kg / hour (4) 4.5 to 6.0 hours: Feed rate 0.25 kg / hour (5) 6.0 to 7.0 hours: Feed rate 0.125 kg / hour The solution temperature in the reactor was controlled at 110 ± 2 ° C. by adjusting the temperature with a jacket. 30 minutes after the start of the polymerization, a monomer mixture for addition was further added from the tank 1 at an addition rate of 306 kg / hour.
Subsequently, 3 hours after the start of polymerization, the entire amount of the monomer mixed solution was added from the tank 2 over 30 minutes at an addition rate of 116 kg / hour.
Thereafter, the polymerization reaction was continued for 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structure in the main chain.
Then, it supplied to the concentration apparatus which consists of the tubular heat exchanger heated beforehand at 170 degreeC, and the vaporization tank, and raised the density | concentration of the polymer contained in a solution to 70 mass%.
The obtained polymerization solution was supplied to a thin film evaporator having a heat transfer area of 0.2 m ² and devolatilized. At this time, devolatilization was performed at an apparatus temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a vacuum degree of 30 Torr, and the polymer after devolatilization was pressurized with a gear pump and extruded from a strand die. After cooling with water, it was pelletized to obtain a methacrylic resin polymer (1-6) having a ring structure in the main chain.
When the composition of the obtained polymer (1-6) was confirmed, the structural units derived from the monomers MMA, phMI, chMI, and styrene were 76.8% by mass, 14.0% by mass, and 4%, respectively. It was 0.0% by mass and 5.2% by mass. Moreover, the weight average molecular weight (Mw _RI ) was 397,000, and the molecular weight distribution (Mw / Mn) _RI was 2.4.

[Production Example 2]
MMA146.0kg, phMI14.6kg, chMI22.0kg, 0.17kg of N- octyl mercaptan a chain transfer agent, were weighed mXy147.0kg, 1.25m ³ reactor equipped with a stirrer and temperature control apparatus according Jacket And stirred to obtain a mixed monomer solution.
Next, 271.2 kg of MMA, 27.1 kg of phMI, 40.9 kg of chMI, and 273.0 kg of mXy were weighed, added to tank 1, and stirred to obtain a mixed monomer solution for addition. Further, MMA 58.0 kg was weighed in the tank 2.
Each of the reactor, tank 1 and tank 2 was bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.
Thereafter, steam was blown into the jacket to raise the temperature of the solution in the reactor to 124 ° C., while stirring at 50 rpm, 0.35 kg of t-butylperoxyisopropyl monocarbonate was dissolved in 4.65 kg of mXy. Polymerization was initiated by adding the solution at a rate of 2 kg / hour.
During polymerization, the temperature of the solution in the reactor was controlled at 124 ± 2 ° C. by adjusting the temperature with a jacket.
30 minutes after the start of the polymerization, the addition rate of the initiator solution was lowered to 1 kg / hour, and a mixed monomer solution for addition was added from tank 1 at 306.2 kg / hour for 2 hours. Then, 2 hours and 45 minutes after the start of polymerization, MMA was added from tank 2 at a rate of 116 kg / hour over 30 minutes. Further, the initiator solution was added at a rate of 0.5 kg / hour after the start of polymerization, 0.5 kg / hour after 4.5 hours, 0.25 kg / hour after 4.5 hours, and 0.125 kg / hour after 6 hours. The addition was stopped later. After 10 hours from the start of polymerization, a polymerization solution containing a methacrylic resin having a ring structure in the main chain was obtained.
This polymerization solution was supplied to a concentrating device composed of a tubular heat exchanger and a vaporization tank preliminarily heated to 170 ° C., 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 and devolatilized. At this time, devolatilization was performed at an apparatus temperature of 280 ° C., a supply amount of 30 L / hr, a rotation speed of 400 rpm, and a degree of vacuum of 30 Torr, and the polymer after devolatilization was pressurized with a gear pump and extruded from a strand die. After cooling with water, it was pelletized to obtain a methacrylic resin polymer (2) having a ring structure in the main chain.
When the composition of the obtained pellet-shaped polymer (2) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 81.3% by mass, 7.9% by mass, and 10.8%, respectively. It was mass%. The weight average molecular weight (Mw _RI ) was 147,000, and the molecular weight distribution (Mw / Mn) _RI was 2.2.

[Production Example 3]
MMA 450.7 kg, phMI 39.8 kg, chMI 59.7 kg, chain transfer agent N-octyl mercaptan 0.41 kg, metaxylene 450 kg were weighed and added to a 1.25 m ³ reactor previously purged with nitrogen, and these were stirred, A mixed monomer solution was obtained.
The mixed monomer solution was then bubbled with nitrogen for 6 hours at a rate of 100 mL / min to remove dissolved oxygen and raise the temperature to 124 ° C.
Next, polymerization was carried out by adding a polymerization initiator solution in which 0.30 kg of t-butylperoxyisopropyl monocarbonate as a polymerization initiator was dissolved in 3.85 kg of metaxylene at a rate of 1 kg / hour.
After 10 hours from the start of polymerization, a polymerization solution containing a methacrylic resin having a ring structure in the main chain was obtained.
Using this polymerization solution, concentration, devolatilization, and granulation were performed in the same manner as in Production Example 1 to obtain a methacrylic resin polymer (3) having a pellet-shaped N-substituted maleimide structural unit.
When the composition of the obtained polymer (3) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 81.3 mass%, 7.9 mass%, and 10.8 mass%, respectively. there were. The weight average molecular weight (Mw _RI ) was 145,000, and the molecular weight distribution (Mw / Mn) _RI was 2.9.

[Production Example 4-1]
In a 1 m ³ reactor equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen gas introduction pipe, the inside of which was previously replaced with nitrogen, 149.6 kg of methyl methacrylate, 37.4 kg of 2- (hydroxymethyl) Methyl acrylate, 0.04 kg tris (2,4-di-t-butylphenyl) phosphite, 149.0 kg of toluene, and 125 g of n-dodecyl mercaptan were charged to prepare a raw material solution. The mixture was stirred while introducing nitrogen, and the reactor internal temperature was raised to 100 ° C.
Separately, an initiator solution in which 0.56 kg of t-amyl peroxyisononanoate and 3.6 kg of toluene were mixed as a polymerization initiator was prepared.
When the raw material solution temperature reached 100 ° C., the initiator solution was added according to the profiles (1) to (6), and polymerization was started.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 1.0 hours: Feed rate 1.0 kg / hour (3) 1.0 to 2.0 hours: Feed rate 0.8 kg / hour (4) 2.0 to 3.0 hours: Feed rate 0.7 kg / hour (5) 3.0 to 4.0 hours: Feed rate 0.35 kg / hour (6) 4. 0 to 7.0 hours: Feed rate 0.27 kg / hour After the addition of the initiator was completed, the reaction was further continued for 2 hours to complete the polymerization reaction.
During the polymerization reaction, the internal temperature was controlled at 105 to 110 ° C.
To the obtained polymer solution, 85 kg of toluene and 170 g of an organic phosphorus compound stearyl phosphate / distearyl phosphate mixture were added as a cyclization catalyst, and the mixture was cyclized under reflux at about 95-100 ° C. for 2 hours. A condensation reaction was performed.
Next, the obtained polymer solution is heated to 240 ° C. with a heater composed of a multi-tube heat exchanger, and then introduced into a vented twin screw extruder having one rear vent and four forevents. The cyclization reaction was allowed to proceed while performing devolatilization.
In the twin screw extruder, the obtained copolymer solution was supplied so as to be 15 kg / hour in terms of resin, and the conditions were a barrel temperature of 260 ° C., a rotation speed of 100 rpm, and a degree of vacuum of 10 to 300 Torr. At that time, a catalyst deactivator (zinc 2-ethylhexylate; manufactured by Nippon Kagaku Sangyo Co., Ltd .: product name Nikka Octix Zinc 18%) was introduced from the two side feeds provided in the latter half of the twin screw extruder . The quenching agent was added at a supply rate of 30 g / hour.
The cyclized polymer that had been cyclized and devolatilized with a twin-screw extruder was extruded from a strand die, cooled with water, and pelletized to obtain a polymer (4-1).
When the composition of the obtained resin composition was confirmed, the content of the lactone ring structural unit was 28.3% by mass. About content of the lactone ring structural unit, it calculated | required according to the method of Unexamined-Japanese-Patent No. 2007-297620. The weight average molecular weight of the obtained resin composition _{(Mw RI)} is 109,000, the molecular weight distribution (Mw / _{Mn) RI} was 2.2.

[Production Example 4-2]
136.6 kg of methyl methacrylate, 37.4 kg of 2- (hydroxymethyl) were added to a 1 m ³ reactor equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen gas introduction pipe, the interior of which was previously replaced with nitrogen Methyl acrylate, 13.0 kg of styrene, 0.04 kg of tris (2,4-di-tert-butylphenyl) phosphite, and 149.0 kg of methyl isobutyl ketone were charged to prepare a raw material solution. The mixture was stirred while introducing nitrogen, and the reactor internal temperature was raised to 100 ° C.
Separately, an additional solution in which 0.56 kg of t-amyl peroxyisononanoate and 6.5 kg of styrene were mixed as a polymerization initiator was prepared.
When the raw material solution temperature reached 100 ° C., the attachment solution was added according to the profiles (1) to (6) to initiate polymerization.
(1) 0.0 to 0.5 hours: Feed rate 2.0 kg / hour (2) 0.5 to 1.0 hours: Feed rate 1.0 kg / hour (3) 1.0 to 2.0 hours: Feed rate 0.8 kg / hour (4) 2.0 to 3.0 hours: Feed rate 0.7 kg / hour (5) 3.0 to 4.0 hours: Feed rate 0.35 kg / hour (6) 4. 0 to 7.0 hours: Feed rate 0.27 kg / hour After the addition of the initiator was completed, the reaction was further continued for 2 hours to complete the polymerization reaction.
During the polymerization reaction, the internal temperature was controlled at 105 to 110 ° C.
To the obtained polymer solution, 85 kg of methyl isobutyl ketone and 170 g of a stearyl phosphate / distearyl phosphate mixture, which is an organic phosphorus compound, as a cyclization catalyst were added, and the mixture was refluxed at about 95-100 ° C. for 2 hours. Cyclocondensation reaction was performed.
Next, the obtained polymer solution is heated to 240 ° C. with a heater composed of a multitubular heat exchanger, and then introduced into a twin-screw extruder with a vent having one rear vent and four forevents. The cyclization reaction was allowed to proceed while performing devolatilization.
In the twin screw extruder, the obtained copolymer solution was supplied so as to be 15 kg / hour in terms of resin, and the conditions were a barrel temperature of 260 ° C., a rotation speed of 100 rpm, and a degree of vacuum of 10 to 300 Torr.
At that time, a catalyst deactivator (zinc 2-ethylhexylate, manufactured by Nippon Kagaku Sangyo Co., Ltd., product name: Nikka Octix Zinc 18%) was introduced from the two side feeds provided in the latter half of the twin-screw extruder. did. The quenching agent was added at a supply rate of 30 g / hour.
The cyclized polymer that had been cyclized and devolatilized with a twin-screw extruder was extruded from a strand die and pelletized after water cooling to obtain a polymer (4-2).
When the composition of the obtained cyclized polymer (4-2) was confirmed, the content of the lactone ring structural unit was 28.3% by mass, and the structural unit derived from the styrene monomer was 6.8% by mass. . About content of the lactone ring structural unit, it calculated | required according to the method of Unexamined-Japanese-Patent No. 2007-297620. The weight average molecular weight of the obtained resin composition _{(Mw RI)} is 232,000, the molecular weight distribution (Mw / _{Mn) RI} was 2.9.

[Production Example 4-3]
In Production Example 4-2, a polymer (4-3) was obtained in the same manner as in Production Example 4-2, except that the polymerization solvent used was changed from methyl isobutyl ketone to toluene.
As a result of confirming the composition of the obtained cyclized polymer, the content of the lactone ring structural unit was 28.3% by mass, and the structural unit derived from the styrene monomer was 6.5% by mass. About content of the lactone ring structural unit, it calculated | required according to the method of Unexamined-Japanese-Patent No. 2007-297620.
The obtained resin composition had a weight average molecular weight (Mw _RI ) of 135,000 and a molecular weight distribution (Mw / Mn) _RI of 2.4.

[Production Example 5]
A reactor having an internal volume of 1 m ³ equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe was charged with 36.5 parts by weight of styrene, 13.5 parts by weight of acrylonitrile, and 50 parts by weight of ethylbenzene as a polymerization solvent. The temperature was raised to 120 ° C. while passing nitrogen through it.
Thereafter, 0.02 parts by mass of t-butyl peroxyisopropyl carbonate was added to initiate polymerization, temperature control was performed so that the temperature of 115 to 125 ° C. could be maintained, and polymerization was continued for 2 hours. The resulting polymer solution was devolatilized by introducing it into a twin screw extruder with a vent having 1 rear vent and 4 forevents.
The polymer that had been devolatilized with a twin screw extruder was extruded from a strand die, cooled with water, and pelletized to obtain a polymer (5) of styrene and acrylonitrile.
When the composition and molecular weight of the obtained copolymer (5) were confirmed, the content of the styrene structural unit was 72.4% by mass, and the weight average molecular weight was 165,000.
[Example 1]
(Preparation of methacrylic resin composition)
The polymer (1-1) obtained in Production Example 1-1 and the polymer (1-2) obtained in Production Example 1-2 were vacuum-dried at 90 ° C. for 5 hours, under a nitrogen atmosphere. It cooled to 30 degreeC and used for preparation of a composition.
Using a tumbler mixer previously purged with nitrogen, 50 parts by mass of the polymer (1-1) and 50 parts by mass of the polymer (1-2), 0.1 part by mass of ADK STAB PEP36, and 0.1% by mass of Irganox 1010 were obtained. A mixture consisting of 05 parts by mass and 0.05 part by mass of ADK STAB AO-412S was prepared.
Using dehumidified air whose dew point was adjusted to −30 ° C. and temperature adjusted to 80 ° C., the resulting mixture was supplied to a 58 mmφ vented twin screw extruder and melt kneaded. At that time, a nitrogen introduction line was provided below the raw material popper attached to the twin-screw extruder, and nitrogen was introduced into the extruder. When the oxygen concentration under the raw material hopper was measured, it was about 1% by volume.
As operating conditions, the lower part of the extruder and the die set temperature of 270 ° C., the rotation speed of 200 rpm, the degree of vacuum at the vent part was 200 Torr, and the discharge rate was 20 kg / hour.
The melt-kneaded resin composition is extruded into a strand shape through a perforated die, introduced into a cooling bath filled with cooling water preheated to 50 ° C., cooled and solidified, cut by a cutter, and formed into a pellet-like composition I got a thing.
When the composition of the obtained pellet-shaped composition (1) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 81.2% by mass, 8.0% by mass, and 10.8%, respectively. It was mass%.
The evaluation results are shown in Table 1.

[Example 2]
The polymer of the methacrylic resin used was added to 50 parts by mass of the polymer (1-1) obtained in Production Example 1-1 and 50 parts by mass of the polymer (1-4) obtained in Production Example 1-4. A composition was prepared in the same manner as in Example 1 except for the changes.
When the composition of the obtained pellet-shaped composition (2) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 85.2% by mass, 3.0% by mass, and 11.8%, respectively. It was mass%.
The evaluation results are shown in Table 1.

[Example 3]
The polymer of the methacrylic resin used is changed to 50 parts by mass of the polymer (1-1) obtained in Production Example 1-1 and 50 parts by mass of the polymer (1-5) obtained in Production Example 1-5. A composition was prepared in the same manner as in Example 1 except that.
When the composition of the obtained pellet-shaped composition (3) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 71.8% by mass, 8.9% by mass, and 19.3%, respectively. It was mass%.
The evaluation results are shown in Table 1.

[Example 4]
The polymer of the methacrylic resin used is changed to 30 parts by mass of the polymer (1-1) obtained in Production Example 1-1 and 70 parts by mass of the polymer (1-2) obtained in Production Example 1-2. A composition was prepared in the same manner as in Example 1 except that.
When the composition of the obtained pellet-shaped composition (4) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 81.5 mass%, 10.4 mass%, and 8.1, respectively. It was mass%.
The evaluation results are shown in Table 1.

[Example 5]
The polymer of the methacrylic resin used is changed to 70 parts by mass of the polymer (1-1) obtained in Production Example 1-1 and 30 parts by mass of the polymer (1-2) obtained in Production Example 1-2. A composition was prepared in the same manner as in Example 1 except that.
When the composition of the obtained pellet-shaped composition (5) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 80.8 mass%, 5.6 mass%, and 13.6, respectively. It was mass%.
The evaluation results are shown in Table 1.

[Example 6]
The polymer of the methacrylic resin used is changed to 50 parts by mass of the polymer (4-1) obtained in Production Example 4-1, and 50 parts by mass of the polymer (4-2) obtained in Production Example 4-2. A composition was prepared in the same manner as in Example 1 except that.
When the composition of the obtained pellet-shaped composition (6) was confirmed, the lactone ring structural unit was 28.3% by mass, and the structural unit derived from the styrene monomer was 3.4% by mass.
The evaluation results are shown in Table 1.

[Example 7]
The polymer of the methacrylic resin used is changed to 70 parts by mass of the polymer (1-1) obtained in Production Example 1-1 and 30 parts by mass of the polymer (1-6) obtained in Production Example 1-6. A composition was prepared in the same manner as in Example 1 except that.
When the composition of the obtained pellet-shaped composition (7) was confirmed, the structural units derived from the monomers MMA, phMI, chMI and styrene were 78.6% by mass, 8.0% by mass, They were 10.8 mass% and 2.6 mass%.
The evaluation results are shown in Table 1.

[Example 8]
Implementation was carried out except that the polymer of the methacrylic resin used was changed to 80 parts by mass of the polymer (4-1) obtained in Production Example 4-1, and 20 parts by mass of the polymer (5) obtained in Production Example 5. A composition was prepared as in Example 1.
When the composition of the obtained pellet-shaped composition (8) was confirmed, the lactone ring structural unit was 22.6% by mass, and the structural unit derived from the styrene monomer was 14.2% by mass.
The evaluation results are shown in Table 1.

[Comparative Example 1]
A composition was prepared in the same manner as in Example 1 except that the polymer of the methacrylic resin used was changed to 100 parts by mass of the polymer (3) obtained in Production Example 3.
When the composition of the obtained pellet-shaped composition (ratio 1) was confirmed, the structural units derived from MMA, phMI, and chMI monomers were 81.3 mass%, 7.9 mass%, and 10. It was 8 mass%.
The evaluation results are shown in Table 1.

[Comparative Example 2]
A composition was prepared in the same manner as in Example 1 except that the polymer of the methacrylic resin used was changed to 100 parts by mass of the polymer (2) obtained in Production Example 2.
When the composition of the obtained pellet-like composition (ratio 2) was confirmed, the lactone ring structural unit was 28.3% by mass, and the structural unit derived from the styrene monomer was 6.5% by mass.
The evaluation results are shown in Table 1.

[Comparative Example 3]
A composition was prepared in the same manner as in Example 1 except that the polymer of the methacrylic resin used was changed to 100 parts by mass of the composition (1-3) obtained in Production Example 1-3. The evaluation results are shown in Table 1.

[Comparative Example 4]
A composition was prepared in the same manner as in Example 1 except that the polymer of the methacrylic resin used was changed to 100 parts by mass of the polymer (4-3) obtained in Production Example 4-3. The evaluation results are shown in Table 1.

  The methacrylic resin composition of the present invention is excellent in transparency, heat resistance and weather resistance, and further, its birefringence is highly controlled. As an optical material, for example, a liquid crystal display Polarizing plate protective films used for displays such as plasma displays, organic EL displays, field emission displays, rear projection televisions, retardation plates such as quarter-wave plates and half-wave plates, and liquid crystals such as viewing angle control films In the field of optical compensation film, display front plate, display substrate, lens, etc., transparent substrate used in solar cells, transparent conductive substrate such as touch panel, optical communication system, optical switching system, optical measurement system. Waveguide, lens, lens array, optical fiber, optical fiber coating material, L D of the lens, to the lens cover and the like can be suitably used.

Claims (10)

The main unit includes a structural unit (X) having a ring structure, and the (X) structural unit is at least one selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer and a lactone ring structural unit. Including two or more kinds of resins including a methacrylic resin and including a structural unit (Y) having an aromatic group,
The glass transition temperature is over 120 ° C. and below 160 ° C.,
The weight average molecular weight (Mw) in terms of polystyrene measured by GPC satisfies the following relationship:
1.1 ≦ Mw _UV / Mw _RI ≦ 2.0
(In the formula, Mw _RI is a weight average molecular weight obtained using a differential refractive index detector, and Mw _UV means a weight average molecular weight obtained using an ultraviolet-visible absorbance detector at a detection wavelength of 254 nm.)
The amount of methanol-soluble component is 5% by mass or less with respect to 100% by mass of the total amount of methanol-soluble component and methanol-insoluble component,
A methacrylic resin composition characterized by that. The resin includes 50 to 95 parts by mass of a methacrylic resin containing a structural unit (X) having a ring structure in the main chain, and 5 to 50 parts by mass of an aromatic vinyl resin.
The glass transition temperature is over 120 ° C. and below 160 ° C.,
The weight average molecular weight (Mw) in terms of polystyrene measured by GPC satisfies the following relationship:
1.1 ≦ Mw _UV / Mw _RI ≦ 2.0
(In the formula, Mw _RI is a weight average molecular weight obtained using a differential refractive index detector, and Mw _UV means a weight average molecular weight obtained using an ultraviolet-visible absorbance detector at a detection wavelength of 254 nm.)
The amount of methanol-soluble component is 5% by mass or less with respect to 100% by mass of the total amount of methanol-soluble component and methanol-insoluble component,
The methacrylic resin composition according to claim 1, wherein The (X) structural unit includes a structural unit derived from an N-substituted maleimide monomer,
2. The methacrylic resin composition according to claim 1, wherein the content of the structural unit derived from the N-substituted maleimide monomer is 5 to 40% by mass with respect to 100% by mass of the methacrylic resin. The (X) structural unit includes a lactone ring structural unit,
2. The methacrylic resin composition according to claim 1, wherein the content of the lactone ring structural unit is 5 to 40% by mass with respect to 100% by mass of the methacrylic resin. The methacrylic resin composition according to any one of claims 1 to 4, wherein the absolute value of the photoelastic coefficient is 2.0 × 10 ^-12 Pa ^-1 or less. The methacrylic resin composition according to claim 5, wherein the absolute value of the photoelastic coefficient is 1.0 × 10 ⁻¹² Pa ⁻¹ or less.   It is comprised with the methacrylic resin composition as described in any one of Claims 1-6, The optical film characterized by the above-mentioned.   An optical component, wherein a functional layer is laminated on at least one of the front and back surfaces of the optical film according to claim 7.   9. The functional layer according to claim 8, wherein the functional layer is at least one selected from the group consisting of a hard coat layer, an antiglare (non-glare) layer, an antireflection layer, a light diffusion layer, an antistatic layer, and an ultraviolet shielding layer. Optical component.   The optical film according to claim 7 and the optical component according to claim 8 or 9, wherein the optical film is a retardation film.