JP6202805B2 - Film containing methacrylic resin - Google Patents

Description

  The present invention relates to a film containing a methacrylic resin.

In recent years, with the expansion of the display market, there has been an increasing demand for clearer viewing of images, and there is a demand for optical materials that are given higher optical properties in addition to transparency, heat resistance, and strength.
As the optical material, acrylic resins have been attracting attention from the viewpoints of transparency, surface hardness, optical properties, and the like.
Conventionally, among acrylic resins, in particular, glutaric anhydride (for example, see Patent Document 1), maleic anhydride (for example, see Patent Document 2), and the like are copolymerized with a (meth) acrylic acid ester monomer. Thus, it has been proposed that an acrylic resin having improved heat resistance is excellent as an optical material.
However, the acrylic resin with improved heat resistance as described above (hereinafter sometimes referred to as a heat-resistant acrylic resin) is a general-purpose acrylic resin, that is, a copolymer of methyl methacrylate and an acrylate ester. Therefore, there is a drawback that high temperature molding tends to cause thermal decomposition. Further, as the molded product becomes larger and thinner (such as a film), there is a disadvantage that foaming may occur during molding processing because molding at a higher temperature and residence time at a higher temperature become longer.

  Furthermore, since heat-resistant acrylic resins have relatively low strength and low toughness, there is a problem that productivity is inferior in terms of film moldability and handling properties.

  Conventionally, as a technique for improving the strength of a heat-resistant acrylic resin, a technique in which a crosslinked elastic body having a multilayer structure is contained in an acrylic resin containing a glutaric anhydride unit has been disclosed (for example, Patent Document 3). reference). Moreover, the technique which adds an acrylic rubber to the acrylic resin containing a maleic anhydride unit is disclosed (for example, refer patent document 4). Furthermore, a technique of adding a multilayer structure rubber and a heat stabilizer to an acrylic resin containing maleic anhydride units is disclosed (for example, see Patent Document 5).

JP 2006-241197 A Japanese Patent Laid-Open No. 03-023404 JP 2000-178399 A JP 05-119217 A JP 2010-126550 A

However, the acrylic resins disclosed in Patent Documents 1 and 2 are insufficient in heat and moisture resistance and thermal stability, and the acrylic resin composition disclosed in Patent Documents 3 and 4 above. However, there is a problem that heat resistance is lowered by the addition of a rubber component, thermal stability is further deteriorated, and foaming and foreign matters are easily generated.
The acrylic resin or the acrylic resin composition disclosed in the cited references 1 to 4 is particularly prone to the acrylic resin, in particular during the film molding, thermal degradation, resin decomposition, generation of foreign matters, etc. are observed. There is a problem that excellent optical properties cannot be sufficiently exhibited.

In addition, in the technique disclosed in Patent Document 5, it is possible to impart excellent mechanical strength and molding stability while adding a certain amount of heat resistance by adding a thermal stabilizer. However, there is a problem that the color tone tends to deteriorate due to the addition of the heat stabilizer, and the heat stabilizer may bleed out during the molding process, which may cause molding defects.
In general, the heat-resistant acrylic resin has relatively poor fluidity, and when a thinner film is produced, it is necessary to increase the melting temperature, and therefore higher molding stability is required.

  In view of the problems of the prior art described above, the present invention has practically sufficient optical properties, excellent heat resistance, moist heat resistance, thermal stability, and molding processability, and mechanical strength is also sufficiently high in practice. An object of the present invention is to provide a film containing a methacrylic resin.

As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have completed the present invention.
That is, the present invention is as follows.

[1]
Methacrylic acid ester monomer unit (A): 50 to 97% by mass;
A structural unit (B) comprising a maleimide structural unit (B-1) and having a ring structure in the main chain: 3% by mass or more and less than 15% by mass ;
When the total amount of the component (A) and the component (B) is 100 parts by mass, the aromatic vinyl monomer unit (C-1) is 5.38 parts by mass to 10 parts by mass. Including
100 parts by weight of methacrylic resin (I) satisfying the following conditions (i) and (ii);
1 to 100 parts by mass of rubbery polymer (II),
A film containing
A film in which the amount of maleimide-based residual monomer in the film is 0.01% by mass or more and 0.5% by mass or less.
(I) The weight average molecular weight measured by gel permeation chromatography (GPC) is 650,000 to 300,000.
(Ii) When the total amount of the component (B −1 ) and the component (C −1 ) is 100% by mass, the mass ratio satisfies the following formula .
0.3 ≦ (C-1) / (B-1) ≦ 1
[2]
The rubbery polymer (II) has an average particle size of 0.03 μm or more and 1 μm or less,
1].
[3]
The film according to [1] or [2] , wherein the structural unit (B) having a ring structure in the main chain includes an N-cyclohexylmaleimide structural unit and / or an N-aryl group-substituted maleimide structural unit.
[4]
The film according to any one of [1] to [3] , wherein the structural unit (B) having a ring structure in the main chain includes an N-aryl group-substituted maleimide structural unit.
[5]
The film according to any one of [1] to [4] , further including 0 to 5 parts by mass of an ultraviolet absorber with respect to 100 parts by mass of the methacrylic resin (I).
[6]
The film according to any one of [1] to [5] , wherein a Vicat softening temperature measured using a molded body containing the methacrylic resin (I) and the rubbery polymer (II) is 110 ° C. or higher. .
[7]
The film according to any one of [1] to [6] , wherein the thickness of the film is 0.01 to 1 mm.
[8]
In TGA (Thermogravimetric Analysis), the film according to any one of [1] to [7] , wherein a weight reduction ratio after heating at a heating temperature of about 270 ° C. for 0.5 hours is 5% or less.

  According to the present invention, it is possible to provide a film containing a methacrylic resin that has high heat resistance, excellent heat and humidity resistance, thermal stability, and molding processability, and has practically sufficient mechanical strength.

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.
Hereinafter, the structural unit constituting the polymer is referred to as “˜monomer unit”.
Moreover, when describing as a constituent material of the methacrylic resin which comprises the film of this embodiment, a "unit" may be abbreviate | omitted and may only be described as "-monomer."

〔the film〕
The film of this embodiment is
Methacrylic acid ester monomer unit (A): 50 to 97% by mass;
At least one selected from the group consisting of a maleimide structural unit, a glutarimide structural unit, and a lactone ring structural unit, a structural unit having a ring structure in the main chain (B): 3 to 30% by mass,
A methacrylic resin (I) 100 containing 0 to 20% by mass of other vinyl monomer units (C) copolymerizable with a methacrylic acid ester monomer and satisfying the following conditions (i) and (ii): Part by mass;
1 to 100 parts by mass of rubbery polymer (II),
Is a film containing
(I): The weight average molecular weight measured by gel permeation chromatography (GPC) is 650,000 to 300,000.
(Ii): When the total amount of the component (B) and the component (C) is 100% by mass, the content of the component (B) is 45% by mass or more and 100% by mass or less.

(Methacrylic resin (I))
The methacrylic resin (I) is
Methacrylic acid ester monomer unit (A): 50 to 97% by mass;
At least one selected from the group consisting of a maleimide structural unit, a glutarimide structural unit, and a lactone ring structural unit, a structural unit having a ring structure in the main chain (B): 3 to 30% by mass,
0-20% by mass of other vinyl monomer units (C) copolymerizable with the methacrylic acid ester monomer,
And satisfy the following conditions (i) and (ii).
(I): The weight average molecular weight measured by gel permeation chromatography (GPC) is 650,000 to 300,000.
(Ii): When the total amount of the component (B) and the component (C) is 100% by mass, the content of the component (B) is 45% by mass or more and 100% by mass or less.

The film of the present embodiment is required to have high heat resistance. From this point of view, the molded product obtained by molding a resin composition containing the methacrylic resin (I) and the rubbery polymer (II) for the film of the present embodiment. The VICAT softening temperature is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, still more preferably 113 ° C. or higher, even more preferably 115 ° C. or higher, even more preferably 117 ° C. or higher, and particularly preferably 120 ° C. or higher. is there.
The VICAT softening temperature can be measured according to ISO 306 B50, and specifically, can be measured by the method described in Examples described later.

It describes in detail about each monomer component of methacrylic resin (I).
<Methacrylic acid ester monomer unit (A)>
The methacrylic acid ester monomer unit (A) constituting the methacrylic resin (I) for a film of the present embodiment (hereinafter sometimes referred to as “component (A)”) is represented by the following general formula (1). A monomer represented by is preferably used.

In the general formula (1), R ₁ represents a methyl group.
R ₂ represents a group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and may have a hydroxyl group on the carbon.
The methacrylic acid ester monomer represented by the general formula (1) is not particularly limited, and examples thereof include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, and methacrylic acid. Examples include cyclohexyl, phenyl methacrylate, methacrylic acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, and methacrylic acid (2,2,2-trifluoroethyl). From the viewpoint of optical properties, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate are preferred. Methyl methacrylate is preferable from the viewpoint of availability.
The said methacrylic acid ester monomer may be used individually by 1 type, and may use 2 or more types together.

  The methacrylic acid ester monomer unit (A) of the methacrylic resin (I) is heat resistant to the methacrylic resin (I) and the film of the present embodiment due to the structural unit (B) having a ring structure in the main chain described later. From the viewpoint of imparting property, 50 to 97% by mass is contained in the methacrylic resin (I), preferably 55 to 97% by mass, more preferably 55 to 95% by mass, and further preferably 60 to 93% by mass. Even more preferably, 60 to 90% by mass is contained.

<Structural unit (B) having a ring structure in the main chain>
The structural unit (B) having a ring structure in the main chain (hereinafter sometimes referred to as component (B)) constituting the methacrylic resin (I) for a film of this embodiment is a maleimide structural unit. And at least one selected from the group consisting of a glutarimide-based structural unit and a lactone ring structural unit.
The structural unit (B) having a ring structure in the main chain may be used alone or in combination of two or more structural units, and two or more monomer units in a common structural unit may be combined. You may use together.

[Maleimide structural unit (B-1)]
As the maleimide structural unit (B-1) constituting the methacrylic resin (I) for a film of the present embodiment, a monomer represented by the following general formula (2) is preferably used.

R ₃ in the general formula (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, and an aryl group having 6 to 12 carbon atoms. Which may have a substituent on the carbon atom.

The monomer for forming the maleimide-based structural unit (B-1) is not particularly limited. For example, maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide; N- Phenylmaleimide, N-methylphenylmaleimide, N-ethylphenylmaleimide, N-butylphenylmaleimide, N-dimethylphenylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N- (o-chlorophenyl) maleimide, N- Examples thereof include N-aryl group-substituted maleimides such as (m-chlorophenyl) maleimide and N- (p-chlorophenyl) maleimide.
From the viewpoint of imparting heat resistance and heat and humidity resistance, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- ( p-chlorophenyl) maleimide, and from the viewpoint of easy availability and imparting heat resistance, more preferred are N-cyclohexylmaleimide and N-phenylmaleimide, and more preferred is N-phenylmaleimide.
The maleimide structural unit (B-1) described above may be used alone or in combination of two or more.

[Glutarimide structural unit (B-2)]
Among the components (B) constituting the methacrylic resin (I) for a film of the present embodiment, as a monomer for forming the glutarimide structural unit (B-2), the following general formula (3) A monomer represented by is preferably used.

Here, in the general formula (3), R ₂₁ and R ₂₂ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.
The alkyl group may be substituted with, for example, a hydroxyl group.
R ₂₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 18 carbon atoms.

The glutarimide-based structural unit (B-2) is obtained by copolymerizing the methacrylic acid ester monomer and / or methacrylic acid and then reacting with ammonia, amine, urea or unsubstituted urea at a high temperature, or polymethacrylic acid. It can be obtained by a known method such as a method of reacting an acid anhydride with ammonia or an amine.
A preferable preparation method includes a method described in US Pat. No. 4,246,374 of RM Kopchik.

[Lactone ring structural unit (B-3)]
Among the components (B) constituting the methacrylic resin (I) for a film of the present embodiment, the monomer for forming the lactone ring structural unit (B-3) is represented by the following general formula (4). The monomers shown are preferably used.

In the formula _{(4), R 31, R} 32, R 33 represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms independently. The organic residue may contain an oxygen atom.
A lactone ring structural unit (B-3) may be used individually by 1 type, and may be used in combination of 2 or more type.
The method for producing the lactone ring-containing polymer is not particularly limited. For example, after polymerizing a polymer having a hydroxyl group and an ester group in the molecular chain, the obtained polymer is treated with the presence / absence of a predetermined catalyst. Examples thereof include a method of producing by introducing a lactone ring structure into a polymer by heat treatment in the presence.

The component (B) contained in the methacrylic resin (I) contains at least one structural unit selected from the group consisting of a glutarimide structural unit and a maleimide structural unit from the viewpoint of thermal stability and molding processability. It is more preferable that it contains a maleimide-based structural unit.
In view of availability, N-cyclohexylmaleimide-based structural units and / or N-aryl-substituted maleimide-based structural units are preferable, and N-aryl-substituted maleimide-based, considering the effect of imparting heat resistance with a small amount of addition. A structural unit is more preferable, and an N-phenylmaleimide-based structural unit is more preferable.

[(B) component ratio]
The structural unit (B) having a ring structure in the main chain is contained in the methacrylic resin (I) in an amount of 3 to 30% by mass from the viewpoints of heat resistance and thermal stability, strength, and fluidity of the film of this embodiment. It is.
From the viewpoint of imparting heat resistance and thermal stability to the film of the present embodiment, it is preferably 5% by mass or more, more preferably 7% by mass or more, and further preferably 8% by mass or more.
Further, from the viewpoint of maintaining the strength and fluidity necessary for the film in a balanced manner, the structural unit (B) having a ring structure in the main chain is preferably 28% by mass or less in the methacrylic resin (I). Preferably it is 25 mass% or less, More preferably, it is 20 mass% or less, More preferably, it is 18 mass% or less, More preferably, it is less than 15 mass%.

[Relationship between structural unit (B) having a ring structure in the main chain and thermal stability]
By including the structural unit (B) having a ring structure in the main chain in the methacrylic resin (I), when the methacrylic resin (I) is placed in a high temperature environment, thermal decomposition is suppressed, and Generation amount can be reduced. Thereby, the improvement effect of the thermal stability of the film of this embodiment is acquired.

<Other vinyl monomer units (C) copolymerizable with methacrylate monomers>
In the methacrylic resin (I) for film of the present embodiment, the monomer constituting the component (A) (hereinafter simply referred to as the component (A) is simply described as long as the effects of the present invention are not impaired. May contain other vinyl monomer units (C) that may be copolymerized (hereinafter may be referred to as component (C)).
The content in the case of using other vinyl monomer units (C) copolymerizable with the component (A) is methacrylic resin (I) from the viewpoint of exerting the heat resistance imparting effect by the component (B). ), 0 to 20% by mass, preferably 0 to 18% by mass, and more preferably 0 to 15% by mass.
When the component (C) is used, the content of the component (B) when the total amount of the component (B) and the component (C) is 100% by mass from the viewpoint of heat resistance and optical properties of the film of the present embodiment. Is 45 mass% or more and 100 mass% or less, and content of (C) component is 0 mass% or more and 55 mass% or less. Preferably, the content of component (B) is 50% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and further preferably 50% by mass or more and 80% by mass or less.

  The monomer for forming the component (C) is not limited to the following, but for example, an aromatic vinyl monomer represented by the following general formula (5), a general formula ( 6) Acrylic ester monomers represented by: vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) ) Ester, ethylene glycol such as acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate or the like, and both terminal hydroxyl groups of its oligomer esterified with acrylic acid or methacrylic acid; neopentyl glycol di (meth) Two alcohols such as acrylate and di (meth) acrylate Those hydroxyl group esterified with acrylic acid or methacrylic acid; trimethylolpropane, those polyhydric alcohol derivatives such as pentaerythritol was esterified with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene, and the like.

In the general formula (5), R ₄₄ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may have a hydroxyl group on the alkyl group.
n represents an integer of 0 to 5.
R ₄₅ 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. And any one of R ₄₅ may be the same group or different groups.
Further, R ₄₅ may form a ring structure.

In the general formula (6), R ₆ is a hydrogen atom, and R ₇ is an alkyl group having 1 to 18 carbon atoms.

  The component (C) can be appropriately selected depending on the properties required for the film of the present embodiment, but properties such as thermal stability, fluidity, mechanical properties, and chemical resistance are particularly necessary. In this case, at least one selected from the group consisting of an aromatic vinyl monomer unit, an acrylate monomer unit, and a vinyl cyanide monomer unit is preferable.

[Aromatic vinyl monomer units (C-1)]
The monomer for forming the aromatic vinyl monomer unit is not particularly limited. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2, 4-dimethylstyrene, 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), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenyl Hexylbenzene, isopropyl Examples include phenyl octylbenzene.
These are appropriately selected according to required characteristics in the film of the present embodiment. 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 content in the case of using the aromatic vinyl monomer unit (C-1) is the sum of the components (A) and (B) in consideration of the balance between heat resistance, reduction of residual monomer species, and fluidity. When the amount is 100 parts by mass, it is preferably 23 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 18 parts by mass or less, still more preferably 15 parts by mass or less, and still more preferably 10 parts by mass. It is below mass parts.

When the aromatic vinyl monomer unit (C-1) is used in combination with the above-described maleimide monomer unit (B-1), the content ratio (mass ratio) is a processing when the film is molded. From the viewpoints of fluidity and the effect of reducing silver streaks due to residual monomer reduction, it is preferable to satisfy the following formula.
0.3 ≦ (C-1) / (B-1) ≦ 5
From the viewpoint of maintaining good color tone and heat resistance, the upper limit value is preferably 5 or less, more preferably 3 or less, and even more preferably 1 or less.
Moreover, it is preferable that it is 0.3 or more from a viewpoint of residual monomer reduction, More preferably, it is 0.4 or more.
The aromatic vinyl monomer (C-1) described above may be used alone or in combination of two or more.

[Acrylic acid ester monomer unit (C-2)]
As the monomer for forming the acrylate monomer unit, as described above, in the general formula (6), a compound in which the substituent R ₇ is an alkyl group having 1 to 18 carbon atoms can be mentioned. Among them, in the methacrylic resin (I) for a film of the present embodiment, methyl acrylate, ethyl acrylate, n-propyl acrylate, from the viewpoint of enhancing weather resistance, heat resistance, fluidity, and thermal stability, Preferred are n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, and the like, and more preferred are methyl acrylate, ethyl acrylate, and n-butyl acrylate. From the viewpoint of ease of handling, methyl acrylate is more preferable.
The content in the case of using the acrylate monomer unit (C-2) is when the total amount of the component (A) and the component (B) is 100 parts by mass from the viewpoints of heat resistance and thermal stability. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less.
As the monomer for forming the acrylate monomer unit (C-2), only one type may be used alone, or two or more types may be used in combination.

[Vinyl cyanide monomer unit (C-3)]
The monomer for forming the vinyl cyanide monomer unit is not particularly limited, and examples thereof include acrylonitrile, methacrylonitrile, vinylidene cyanide and the like. From the viewpoint of imparting chemical properties, acrylonitrile is preferred.
In the case of using the vinyl cyanide monomer unit (C-3), the total amount of the component (A) and the component (B) is 100 parts by mass from the viewpoint of solvent resistance and heat resistance. When it is, it is preferable that it is 15 mass parts or less, More preferably, it is 12 mass parts or less, More preferably, it is 10 mass parts or less.

  Among the monomers constituting the component (C) described above, at least one monomer selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile is preferable from the viewpoint of availability. .

<Molecular weight and molecular weight distribution of methacrylic resin (I)>
The methacrylic resin (I) for film of this embodiment has a weight average molecular weight of 650,000 or more and 300,000 or less. By setting the weight average molecular weight of the methacrylic resin (I) within the above range, the film of this embodiment is excellent in mechanical strength, solvent resistance and fluidity. Preferably it is 650,000-250,000, More preferably, it is 70,000-230,000.
The molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the methacrylic resin (I) is 1.5 or more and 5 or less in consideration of the balance of fluidity, mechanical strength, and solvent resistance. Is preferred. More preferably, it is 1.5 or more and 4.5 or less, More preferably, it is 1.6 or more and 4 or less, More preferably, it is 1.6 or more and 3 or less, More preferably, it is 1.5 or more and 2.5 or less.
The weight average molecular weight and number average molecular weight of the methacrylic resin (I) for a film of the present embodiment can be measured by gel permeation chromatography (GPC).
That is, using a standard methacrylic resin that is known in advance as a reagent and has a monodispersed weight average molecular weight, number average molecular weight, and peak molecular weight, and an analytical gel column that elutes a high molecular weight component first, elution time and weight average molecular weight Create a calibration curve. Next, from the obtained calibration curve, the weight average molecular weight and the number average molecular weight of the sample of the methacrylic resin to be measured can be obtained.
Specifically, it can measure by the method as described in the Example mentioned later.

(Residual monomer amount)
In the film of the present embodiment, the residual monomer is 0.1% by mass to 1.5% by mass in the film of the present embodiment, considering the balance of heat resistance, fluidity, processability at molding, and scratch resistance. It is preferable that More preferably 0.1% by mass to 1% by mass, further preferably 0.2% by mass to 1% by mass, even more preferably 0.2% by mass to 0.8% by mass, and still more preferably 0.3% by mass. % To 0.8% by mass.
The amount of residual monomer can be measured by gas chromatography, and specifically can be measured by the method described in the examples described later.
The residual monomer here means the monomer remaining in the resin, that is, the components (A), (B), (C) contained in the methacrylic resin (I), and measured by gas chromatography. It refers to the component that can be made.

  In addition, when using a maleimide monomer as the component (B), from the viewpoint of color tone and fluidity, heat resistance, thermal stability and scratch resistance, the monomer content of the remaining maleimide monomer (hereinafter, The amount of the maleimide-based residual monomer and the amount of MI-based residual monomer may be described as 0.01) to 0.5% by mass in the film of this embodiment. More preferably 0.02% by mass to 0.5% by mass, even more preferably 0.02% by mass to 0.4% by mass, even more preferably 0.02% by mass to 0.3% by mass, and still more preferably. It is 0.03 mass%-0.25 mass%.

(Method for producing methacrylic resin (I))
Hereinafter, although the manufacturing method of methacrylic resin (I) for films of this embodiment is explained, it is not limited to the method shown below.
The methacrylic resin (I) can be copolymerized with the methacrylic acid ester monomer unit (A), the structural unit (B) having a ring structure in the main chain, and the methacrylic acid ester monomer as necessary. Such other monomers for forming the vinyl monomer unit (C) can be used to produce the polymer by bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, or emulsion polymerization. A bulk polymerization method, a solution polymerization method and a suspension polymerization method are preferably used, a solution polymerization method and a suspension polymerization method are more preferable, and a suspension polymerization method is more preferably used.

<Production method by solution polymerization method>
When the methacrylic resin (I) is produced by the solution polymerization method, an organic solvent which is a good solvent for the methacrylic resin is used in consideration of the removal efficiency in the step of removing the monomer remaining in the methacrylic resin (I). It is preferable.
Considering the solubility of the copolymer constituting the methacrylic resin (I), the solubility parameter δ of the organic solvent is preferably 7.0 to 12.0 (cal / cm ³ ) ^1/2 , more preferably ^{8.0~11.0 (cal / cm 3) 1/2} , still more preferably ^{8.2~10.5 (cal / cm 3) 1/2} .
The value of the solubility parameter δ and how to obtain the value are described in, for example, K. P. P-P118 in Non-Patent Document “Journal of Paint Technology Vol. 42, No. 541, February 1970”. L. Hoy “New Values of the Solubility Parameters From Vapor Pressure Data” For example, Brandrup et al., “Polymer Handbook Fourth Edition” P-VII / 675-P714 can be referred to.
1 (cal / cm ³ ) ^1/2 is about 0.489 (MPa) ^1/2 .

The addition amount of the organic solvent used in the polymerization step of the methacrylic resin for film (I) of the present embodiment is an amount that can be easily removed without the occurrence of precipitation of the copolymer or the used monomer during the production. It is preferable that
When the polymerization of the methacrylic resin (I) is performed by a solution polymerization method, the blending amount of the organic solvent is specifically 10 parts by mass or more and 200 parts by mass when the total amount of monomers to be blended is 100 parts by mass. Part or less. More preferably, they are 25 mass parts or more and 200 mass parts or less, More preferably, they are 50 mass parts or more and 200 mass parts or less, More preferably, they are 50 mass parts or more and 150 mass parts or less.

The polymerization temperature in the case of producing the methacrylic resin (I) by solution polymerization may be any temperature at which polymerization proceeds, but is preferably 50 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. from the viewpoint of productivity. It is at least 200 ° C. More preferably, it is 90 degreeC or more and 200 degrees C or less, More preferably, it is 100 degreeC or more and 180 degrees C or less, More preferably, it is 110 degrees C or more and 170 degrees C or less.
In addition, the polymerization time is not particularly limited as long as the required degree of polymerization can be obtained, but from the viewpoint of productivity and the like, it is preferably 0.5 hours or more and 10 hours or less, more preferably 1 hour. More than 8 hours.
The concentration of dissolved oxygen in the polymerization solution in the polymerization step of the methacrylic resin (I) is not particularly limited, but is preferably 10 ppm or less. The dissolved oxygen concentration can be measured using, for example, a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.). As a method for lowering the dissolved oxygen concentration, a method of bubbling an inert gas in the polymerization solution, and an operation of 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.

<Production method by suspension polymerization method>
When the methacrylic resin for film (I) of the present embodiment is produced by suspension polymerization such as organic suspension polymerization method or inorganic suspension polymerization method, a polymerization step using a stirring device described later, a washing step, A particulate methacrylic resin (I) is produced through a dehydration step and a drying step.
Usually, an aqueous suspension polymerization method using water as a medium is preferably used.
<Polymerization process>
Using a stirrer to be described later, a monomer, a suspending agent, and a polymerization initiator and other additives as necessary are appropriately fed into the stirrer to perform polymerization, and a methacrylic resin slurry is prepared. obtain.
The stirrer used in the polymerization process to obtain methacrylic resin by suspension polymerization method includes inclined paddle blade, flat paddle blade, propeller blade, anchor blade, fiddler blade (retracted blade), turbine blade, bull margin Stirring devices with stirring blades such as blades, Max blend blades, full zone blades, ribbon blades, supermix blades, intermig blades, special blades and axial flow blades, stirring devices with shovel blades inside, chopper blades inside Examples of the stirring device include known stirring devices such as a stirring device having a rotating disk such as a disk type, a notch disk type, or a screw type.
The stirring speed at the time of polymerization depends on the type of stirring device used, the stirring efficiency of the stirring blade, the capacity of the polymerization tank, etc., but it is possible to obtain an appropriate particle size, and a component having a particle size of less than 0.15 mm Considering that the amount can be reduced, polymerization stability and the like, it is preferably about 1 to 500 revolutions / minute.

In the polymerization step of the methacrylic resin (I), the temperature at which the raw material is added may be within a range where the effects of the present invention can be exerted, and is preferably 0 ° C. or higher and lower than the boiling point of the raw material to be used.
If the temperature is high, the raw material tends to volatilize at the time of addition, so the composition of the resulting copolymer may change. In addition, depending on the raw material used, there is a possibility that the raw material may be partly hydrolyzed due to contact with water at a high temperature, which may cause a change in color tone under humid heat conditions. When the temperature is lower than 0 ° C., it takes time to increase the temperature after the addition of the raw material, and therefore it is preferable to add the raw material mixture at a certain temperature.
Specifically, it is preferably 0 ° C or higher and 85 ° C or lower, more preferably 10 ° C or higher and 85 ° C or lower, further preferably 10 ° C or higher and 80 ° C or lower, and even more preferably 15 ° C or higher and 70 ° C or lower, More preferably, it is 15 degreeC or more and 60 degrees C or less.

The temperature in the suspension polymerization step is preferably 40 ° C. or higher and 90 ° C. or lower in consideration of productivity and the amount of aggregates produced. More preferably, they are 50 degreeC or more and 85 degrees C or less, More preferably, they are 60 degreeC or more and 80 degrees C or less, More preferably, they are 65 degreeC or more and 80 degrees C or less.
In the case of producing by suspension polymerization, the polymerization time is preferably 20 minutes or more and 240 minutes or less from the viewpoint of effectively suppressing heat generation during polymerization and reducing the generation of aggregates and the residual monomer to be described later. is there. More preferably, they are 30 minutes or more and 210 minutes or less, More preferably, they are 45 minutes or more and 180 minutes or less, More preferably, they are 60 minutes or more and 180 minutes or less, More preferably, they are 90 minutes or more and 150 minutes or less.

Further, from the viewpoint of reducing the residual monomer, it is preferable to raise the temperature to a temperature higher than the polymerization temperature after the polymerization step and hold it for a certain time.
The temperature at the time of holding is preferably higher than the polymerization temperature from the viewpoint that the degree of polymerization can be increased, and is preferably raised by 5 ° C. or more from the polymerization temperature.
When raising temperature, it is preferable that it is below the glass transition temperature of methacrylic resin (I) obtained from a viewpoint which prevents aggregation of the polymer obtained. Specifically, it is 120 ° C. or lower, preferably 80 ° C. or higher and 120 ° C. or lower, more preferably 90 ° C. or higher and 120 ° C. or lower, even more preferably 93 ° C. or higher and 120 ° C. or lower, even more preferably 93 ° C. or higher and 110 ° C. or lower. It is.

By performing polymerization according to the polymerization temperature and holding time described above, polymer particles having a small angle of repose can be obtained after the drying step described below.
The time for maintaining the temperature after the temperature rise is preferably 15 minutes or more and 360 minutes or less, more preferably 30 minutes or more and 240 minutes or less, more preferably 30 minutes or more and 180 minutes, in view of the effect of reducing the residual monomer. Hereinafter, it is more preferably 30 minutes or longer and 150 minutes or shorter, and even more preferably 30 minutes or longer and 120 minutes or shorter.

<Washing process>
The slurry of the methacrylic resin (I) obtained through the above-described polymerization step is preferably subjected to a washing step such as acid washing, water washing, and alkali washing in order to remove the suspending agent.
In these washing steps, the number of times of washing operation may be selected from the work efficiency and the suspension removal efficiency, and may be repeated once or multiple times.
What is necessary is just to select the temperature at the time of performing washing | cleaning operation in consideration of the removal efficiency of a suspension agent, the coloring degree of the copolymer obtained, etc., and it is preferable that it is 20-100 degreeC. More preferably, it is 30-95 degreeC, More preferably, it is 40-95 degreeC.

  In addition, the cleaning time per cleaning operation is preferably 10 to 180 minutes, more preferably 20 to 150 minutes, from the viewpoints of cleaning efficiency, repose angle reduction effect, and process simplicity.

The pH of the cleaning solution used at the time of the cleaning may be within a range where the suspension can be removed, but is preferably pH 1-12.
The pH for acid washing is preferably pH 1-5, more preferably pH 1.2-4, from the viewpoint of the removal efficiency of the suspending agent and the color tone of the resulting copolymer. The acid used at that time is not particularly limited as long as the suspending agent can be removed, and conventionally known inorganic acids and organic acids can be used. As an example of the acid that is preferably used, the inorganic acid includes hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid and the like, and each may be used in a diluted solution diluted with water or the like. Examples of the organic acid include those having a carboxyl group, a sulfo group, a hydroxy group, a thiol group, or an enol. Considering the effect of removing the suspending agent and the color tone of the resulting resin, more preferred are nitric acid, sulfuric acid, and organic acids having a carboxyl group.
After the acid cleaning, it is preferable to further perform water washing or alkali washing from the viewpoint of reducing the color tone and angle of repose of the polymer obtained.
The alkaline solution used for the alkali cleaning is preferably pH 7.1 to 12, more preferably pH 7.5 to 11, and further preferably pH 7.5 to 10.5.
Although the alkaline component used for alkali washing is not limited to the following, for example, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are preferably used. Alkali metal hydroxides and alkaline earth metal hydroxides are more preferable, and lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, hydroxide are more preferable. Calcium and barium hydroxide are more preferable, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide are more preferable, and sodium hydroxide and potassium hydroxide are still more preferable.
These alkaline components can be used by adjusting the pH by diluting with water or the like.

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

<Drying process>
The water-containing methacrylic resin (I) obtained through the dehydration step described above can be recovered by performing a drying treatment by a known method.
For example, hot air drying for drying by sending hot air into the tank from a hot air blower or blow heater, etc., vacuum drying for drying by heating as necessary after reducing the pressure inside the system, and the obtained polymer For example, barrel drying for removing moisture by rotating the container in a container, spin drying for drying using centrifugal force, and the like.
These methods may be used alone or in combination.

  The water content of the obtained methacrylic resin (I) is preferably 0.01% by mass to 1% by mass, more preferably, considering the handleability and color tone of the obtained methacrylic resin (I). It is 0.05 mass%-1 mass%, More preferably, it is 0.1 mass%-1 mass%, More preferably, it is 0.27 mass%-1 mass%. The water content of the resulting methacrylic resin (I) can be measured using the Karl Fischer method.

When the methacrylic resin (I) is produced by using the suspension polymerization method described above, the resulting methacrylic resin (I) is usually substantially spherical, but some aggregates may be formed.
The said aggregate refers to the residue which remains on a sieve, when the obtained polymer is passed through a 1.68 mm mesh sieve.
When the aggregate remains in the methacrylic resin (I), the color tone of the resulting methacrylic resin (I) tends to decrease. The amount of aggregates in the methacrylic resin (I) is preferably 1.2% by mass or less, more preferably 1.0% by mass or less.
The agglomerate content was determined by measuring the weight after passing through a sieve of 1.68 mm mesh and drying what was left on the sieve in a drying oven at 80 ° C. for 12 hours, and the obtained weight was the total amount of raw materials. It is obtained by dividing by the calculation of the aggregate production (mass%).

The average particle diameter of the methacrylic resin (I) obtained by using the above-described suspension polymerization method is 0.1 mm in consideration of the molding processability of the film of the present embodiment and the workability during extrusion during pelletizing. In consideration of the color tone of the film of the present embodiment, it is more preferably 0.1 mm or more and 1 mm or less, further preferably 0.1 mm or more and 0.5 mm or less, and even more preferably 0.1 mm or more. 0.4 mm or less.
The average particle diameter of the methacrylic resin (I) can be measured based on, for example, JIS-Z8801, and sieves (Tokyo Screen JTS-200-45-44 (aperture 500 μm), 34 (aperture 425 μm)). , 35 (aperture 355 μm), 36 (aperture 300 μm), 37 (aperture 250 μm), 38 (aperture 150 μm), 61 (a saucer)), and vibration using a screening tester TSK B-1 It can be measured by measuring the weight of particles remaining on each sieve when sieving with force MAX for 10 minutes and determining the particle diameter when the weight is 50%.

In various polymerization methods for producing the methacrylic resin (I) contained in the film of the present embodiment, that is, in the polymerization step in the bulk polymerization method, the solution polymerization method, the suspension polymerization method, or the emulsion polymerization method, For the purpose of adjusting the degree of polymerization, a polymerization initiator may be used.
The polymerization initiator is not limited to the following when performing radical polymerization, but examples thereof include di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, and t-butyl peroxide. Oxyneodecanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3 , 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, and the like, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1- Cyclohexanecarbonitrile), 2,2'-azobis-4-methoxy-2,4-azo Azo-based general radical polymerization initiators such as sisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-2-methylbutyronitrile and the like can be mentioned. .
These may be used alone or in combination of two or more.
A combination of these radical polymerization initiators and an appropriate reducing agent may be used as a redox initiator.
These polymerization initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used, taking into consideration the polymerization temperature and the half-life of the initiator. Can be selected as appropriate.

When a bulk polymerization method, a cast polymerization method, or a suspension polymerization method is selected as the polymerization method for the methacrylic resin (I), from the viewpoint of preventing the methacrylic resin (I) from being colored, lauroyl parper is a peroxide-based initiator. Oxide, decanoyl peroxide, t-butylperoxy-2-ethylhexanoate and the like can be particularly preferably used, and lauroyl peroxide is particularly preferably used.
In addition, in the case of performing solution polymerization or bulk polymerization at a high temperature of 90 ° C. or higher, a peroxide, azobis initiator, etc. having a 10-hour half-life temperature of 80 ° C. or higher and soluble in the organic solvent to be used preferable. Such a polymerization initiator is not limited to the following, and examples thereof include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, and 2,5-dimethyl. Examples include -2,5-di (benzoylperoxy) hexane, 1,1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like.
These polymerization initiators are preferably used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used.

In the production process of the methacrylic resin (I) contained in the film of the present embodiment, the molecular weight of the polymer to be produced can be controlled within a range that does not impair the object of the present invention.
For example, the molecular weight can be controlled by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine; iniferters such as dithiocarbamates, triphenylmethylazobenzene, tetraphenylethane derivatives, etc. Can control the molecular weight by adjusting the addition amount of these chain transfer agents and iniferters.
When these chain transfer agents and iniferters are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability, and are not limited to the following. For example, n-butyl mercaptan, n-octyl mercaptan are used. , N-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) ) And the like.
These can be appropriately added according to the required molecular weight, but generally used in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all monomers used. .
Other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, and a method of changing the polymerization temperature.
As these molecular weight control methods, only one type of method may be used alone, or two or more types may be used in combination.

(Rubber polymer (II))
The film of this embodiment contains 1 to 100 parts by mass of the methacrylic resin (I) described above and 100 parts by mass of the rubbery polymer (II).
By containing the rubber polymer (II), the effect of imparting strength to the film can be obtained.

The rubbery polymer (II) is not particularly limited as long as it can exert an effect of imparting strength, and a known material can be used.
For example, rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluororubber can be used. When high transparency is required in the film of the present embodiment, the rubber polymer (II) having a refractive index close to that of the methacrylic resin (I) described above can be preferably used, and the acrylic rubber weight A coalescence can be used particularly preferably.

  The content of the rubber-like polymer (II) in the film of the present embodiment is the above-mentioned methacrylic resin (from the viewpoint of required properties such as heat resistance retention, imparting impact resistance, fluidity, and mechanical properties). I) It is 1-100 mass parts with respect to 100 mass parts of components, Preferably it is 10-100 mass parts, More preferably, it is 20-100 mass parts.

The rubbery polymer (II) preferably used in the present embodiment is not limited to the following, but for example, the following conventionally proposed acrylic rubbery polymers can be applied. .
<Example 1: Rubber polymer disclosed in JP-B-60-17406>
The rubbery polymer of Example 1 is a multilayer structure particle produced by the following steps (A) to (C).
Step (A): Dispersion of a polymer mainly composed of methyl methacrylate by emulsion polymerization of methyl methacrylate alone or a mixture of methyl methacrylate and a monomer copolymerizable therewith, and having a glass transition point of 25 ° C. or higher. A first layer forming step.
Step (B): an alkyl acrylate that forms a copolymer having a glass transition point of 25 ° C. or lower when polymerized to the product obtained by the step (A), and a monomer copolymerizable therewith, or A second layer step in which a mixture containing a polyfunctional crosslinking agent and 0.1 to 5% by mass of a polyfunctional grafting agent based on the total weight of the mixture is added and subjected to emulsion polymerization.
Step (C): Concatenating methyl methacrylate or a monomer mixture mainly composed thereof, which forms a polymer having a glass transition point of 25 ° C. or higher when polymerized to the product obtained in the step (B). A third layer forming step of emulsion polymerization in multiple stages while increasing the transfer agent stepwise.
The multilayer structured particles are multilayer structured particles made of acrylic rubber in which the molecular weight of the third layer gradually decreases from the inside toward the outside.

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

<Example 3: Rubber polymer disclosed in JP-B-7-68318>
The rubbery polymer of Example 3 is a multilayer structure acrylic polymer having the following requirements (a) to (g).
That is, the multilayer structure acrylic polymer is
(A) 90 to 99% by mass of methyl methacrylate, 1 to 10% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and allyl, methallyl, or clothy of α, β-unsaturated carboxylic acid copolymerizable therewith. The innermost hard layer polymer 25-45 mass obtained by polymerizing a monomer mixture consisting of 0.01 to 0.3 mass% of a graft-bondable monomer consisting of at least one selected from the group consisting of %When,
(B) In the presence of the innermost hard layer polymer, 70 to 90% by mass of n-butyl acrylate, 10 to 30% by mass of styrene, and allyl, methallyl of α, β-unsaturated carboxylic acid copolymerizable therewith, Or the soft layer polymer 35-45 mass obtained by superposing | polymerizing a monomer mixture which consists of 1.5-3.0 mass% of graft-bonding monomers which consist of at least 1 sort (s) chosen from the group which consists of a crotyl ester. %When,
(C) In the presence of the innermost hard layer polymer and the soft layer polymer, 90 to 99% by mass of methyl methacrylate and 1 to 10% by mass of a monomer having 1 to 8 carbon atoms in the alkyl group. The outermost hard layer polymer 20-20% by mass obtained by polymerizing the mixture,
(D) The weight ratio of soft layer polymer / (innermost hard layer polymer + soft layer polymer) is 0.45 to 0.57,
(E) A multilayer structure acrylic polymer having an average particle size of 0.2 to 0.3 μm, and when the multilayer structure acrylic polymer is further fractionated with acetone,
(F) The graft ratio is 20 to 40% by mass,
(G) A multilayer acrylic polymer in which the tensile modulus of elasticity of the acetone insoluble part is 1000 to 4000 kg / cm ² .

In addition, examples of the rubber polymer (II) include the following particles.
For example, JP-B-55-27576, JP-B-58-1694, JP-B-59-36645, JP-B-59-36646, JP-B-62-41241, JP-A-59-202213 Acrylic rubber having a three- to four-layer structure described in JP-A-63-27516, JP-A-51-129449, JP-A-52-56150, JP-A-50-124647, etc. Particles can also be used.

<Layer structure of rubbery polymer (II)>
The rubbery polymer (II) contained in the film of this embodiment preferably has a multilayer structure.
When the rubber polymer (II) has a multilayer structure, the larger the number of layers of the rubber polymer, the more the elasticity can be controlled within a suitable range. In consideration of the film color tone and the like when it is contained, it is preferably a particle having a three-layer structure or more, and more preferably an acrylic rubber particle having a three-layer structure or more.
By using rubber particles having the above three-layer structure as the rubber polymer (II), thermal deterioration during the molding process of the film of the present embodiment and deformation of the rubber polymer (II) due to heating are suppressed. The heat resistance and transparency of the film tend to be maintained.

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

The rubbery polymer (II) composed of three layers can be formed by, for example, a multilayer structure graft copolymer. The multilayer structure graft copolymer can be produced using, for example, methyl methacrylate and a monomer copolymerizable with the methyl methacrylate.
The monomer copolymerizable with methyl methacrylate is not limited to the following, but examples include known (meth) acrylic acid, (meth) acrylates other than methyl methacrylate, styrene, and α-methylstyrene. Monofunctional monomers such as ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, tri Examples thereof include polyfunctional monomers such as allyl isocyanurate, diallyl maleate, and divinylbenzene.
The said monomer can be used 1 type or in combination of 2 or more types as needed.

Specifically, when the rubbery polymer (II) has a three-layer structure, the copolymer forming the innermost layer is 65 to 90% by mass of methyl methacrylate and other copolymerizable with this. A copolymer using 10 to 35% by mass of a copolymerizable monomer is preferable.
From the viewpoint of appropriately controlling the refractive index, the other copolymerizable monomer copolymerizable with the methyl methacrylate is 0.1 to 5% by mass of an acrylate monomer and a single amount of an aromatic vinyl compound. It is preferable that 5-35 mass% of a body and 0.01-5 mass% of copolymerizable polyfunctional monomers are included.
In the case where the rubbery polymer (II) has a three-layer structure, the acrylate monomer in the copolymer forming the innermost layer is not particularly limited. For example, n-butyl acrylate, acrylic The acid 2-hexyl is preferred.
As the aromatic vinyl compound monomer, the same monomers as those used for the methacrylic resin (I) can be used. Preferably, the refractive index of the innermost layer is adjusted to adjust the refractive index of the inner layer. From the viewpoint of improving the transparency of the film, styrene or a derivative thereof is used.
The copolymerizable polyfunctional monomer is not particularly limited, but preferably ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1, Examples include 4-butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, and divinylbenzene. These may be used alone or in combination of two or more. Among these, allyl (meth) acrylate is more preferable.

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

In the case where the rubber polymer (II) has a three-layer structure, the outermost layer is composed of 70 to 100% by mass of methyl methacrylate and 0 to 30% by mass of other copolymerizable monomers copolymerizable therewith. It is preferable that it is formed by the copolymer containing these.
Although it does not specifically limit as another copolymerizable monomer copolymerizable with the methyl methacrylate which forms the said outermost layer, For example, n-butyl acrylate and 2-hexyl acrylate are mentioned as a preferable thing .

When rubbery polymer (II) is comprised from three layers, rubbery polymer (II) may contain the rubber-like polymer which has a crosslinked structure.
The rubbery polymer having the crosslinked structure is preferably contained in the second layer, and a rubbery polymer having a crosslinked structure formed by copolymerizing a polyfunctional monomer can be applied.
The crosslinked structure in the rubber-like polymer gives moderate rubber elasticity, and can maintain its form in a dispersed state without dissolving in the monomer mixture.
As a polyfunctional monomer for forming a crosslinked structure, a compound copolymerizable with methyl methacrylate and methyl acrylate can be used, and the amount used is 0.1 to 5 with respect to the entire second layer. It is preferable that it is mass%.
When the amount of the polyfunctional monomer used is 0.1% by mass or more, a sufficient crosslinking effect is obtained, and when it is 5% by mass or less, an appropriate rubber strength and an excellent rubber elasticity effect are obtained.
Further, when the amount of the polyfunctional monomer used is 0.1% by mass or more, even when the cast polymerization step is performed, the rubbery polymer does not dissolve or swell, and the form of the rubbery elastic body Can be held.

Furthermore, it is preferable to use a polyfunctional grafting agent for forming a graft bond that closes the affinity with the polymer of the third layer described later in the second layer.
The polyfunctional grafting agent is a polyfunctional monomer having a different functional group and is not limited to the following, but examples include allyl esters such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Of these, allyl acrylate and allyl methacrylate are preferred. It is preferable that the usage-amount of a polyfunctional grafting agent is the range of 0.1-3 mass% with respect to the whole 2nd layer.
When the amount of the polyfunctional grafting agent used is 0.1% by mass or more, a sufficient grafting effect is obtained, and when it is 3% by mass or less, a decrease in rubber elasticity can be prevented.

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

In order to improve the transparency of the film of this embodiment, it is necessary to match the refractive indexes of the dispersed rubbery polymer (II) and the methacrylic resin (I). In addition, when alkyl acrylate is used as the main component in the second layer, it is extremely difficult to make the refractive index of the second layer completely coincide with that of the methacrylic resin (I). In order to match the refractive index, for example, in the second layer, when alkyl acrylate and styrene or its derivatives are copolymerized, the refractive index becomes substantially equal in a certain temperature range and the transparency is improved. A refractive index shift occurs and transparency is deteriorated.
As a means for avoiding this, there is a method of providing a first layer having a refractive index substantially equal to that of the methacrylic resin (I). In addition, reducing the thickness of the second layer is also effective in preventing deterioration of the transparency of the film of the present embodiment.

<Method for producing rubber polymer (II)>
The rubbery polymer (II) can be produced by emulsion polymerization.
Specifically, when the rubbery polymer (II) is composed of three layers as described above, the first monomer mixture is first added in the presence of an emulsifier and a polymerization initiator to perform polymerization. The rubbery polymer (particles) can be easily prepared by adding the second layer monomer mixture to complete the polymerization, and then adding the third layer monomer mixture to complete the polymerization. ) As a latex.
This rubbery polymer (II) can be recovered from the latex as a powder by a known method such as salting out, spray drying, freeze drying and the like.
When the rubber polymer (II) is a polymer composed of three layers, aggregation of the particles of the rubber polymer (II) can be avoided by providing a hard layer in the third layer. .

<Average particle diameter of rubbery polymer (II)>
Moreover, the average particle diameter of rubber-like polymer (II) is 0.03-1 micrometer from the viewpoint of the impact strength provision effect of the film of this embodiment, a viewpoint of surface smoothness, and a desired film thickness. Preferably there is. More preferably, they are 0.05 micrometer-0.7 micrometer, More preferably, they are 0.05 micrometer-0.5 micrometer, More preferably, they are 0.05 micrometer-0.4 micrometer, More preferably, they are 0.05 micrometer-0.3 micrometer.
When the average particle diameter of the rubber polymer (II) is 0.03 μm or more, sufficient impact strength tends to be obtained in the film of this embodiment, and when it is 1 μm or less, the surface of the film of this embodiment In addition, the appearance of fine ripples can be prevented to obtain mirror surface properties. Further, when thermoformed, a reduction in surface gloss can be suppressed in the stretched portion, and transparency can be ensured.

As a method for measuring the average particle diameter of the rubber polymer (II), a conventionally known method can be used, and examples thereof include the methods shown in the following (1) and (2).
(1) After cutting out a part of the molded product of the methacrylic resin composition with a circular saw, a sample for observation by a RuO ₄ (ruthenic acid) dyed ultrathin section method was prepared, and manufactured by Hitachi Type electron microscope model: Take a picture after observing the cross section of the dyed rubber particles using H-600 type. The average particle diameter of rubber particles is obtained by measuring the diameter of 20 representative particles printed at a high magnification on a scale and obtaining the average value of the diameters of the particles.
(2) An emulsion of rubber polymer (II) is sampled, diluted with water to a solid content of 500 ppm, and absorbance at a wavelength of 550 nm using a UV 1200 V spectrophotometer (manufactured by Shimadzu Corporation). From this value, the average particle size is determined using a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle size was measured from a transmission electron micrograph.
In the measurement methods (1) and (2), almost the same particle diameter measurement values can be obtained.

  In the film of the present embodiment, the difference between the refractive index of the methacrylic resin (I) and the refractive index of the rubbery polymer (II) from the viewpoint of high transparency, transparency, particularly transparency temperature dependency. It is preferable that it is 0.015 or less, More preferably, it is 0.012 or less, More preferably, it is 0.01 or less.

(Other resins)
The film of the present embodiment may contain a combination of other resins in addition to the methacrylic resin (I) described above.
As the other resin, a known thermoplastic resin can be used as long as it can exhibit the characteristics required for the film of the present embodiment.
Examples of the thermoplastic resin include, but are not limited to, polyethylene resins, polypropylene resins, polystyrene resins, syndiotactic polystyrene resins, polycarbonate resins, ABS resins, acrylic resins, Polyalkylene arylates such as AS resin, BAAS resin, MBS resin, AAS resin, biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate Resins: Polyamide resins, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like.
In particular, AS resin and BAAS resin are preferable from the viewpoint of improving fluidity, ABS resin and MBS resin are preferable from the viewpoint of improving impact resistance, and polyester resin is preferable from the viewpoint of improving chemical resistance.
Polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like are preferable from the viewpoint of improving flame retardancy.
Polycarbonate resins are preferred when it is necessary to impart heat resistance, impact resistance or optical properties.
Furthermore, the acrylic resin has good compatibility with the methacrylic resin described above, and is preferable when adjusting characteristics such as fluidity and impact resistance while maintaining transparency.
The various thermoplastic resins may be used alone or in combination of two or more resins.

In the film of the present embodiment, when the methacrylic resin (I) described above and the other resin are used in combination, these blending ratios may be in a range in which the effects of the present invention can be exhibited. In consideration of the effect of imparting the above-mentioned ratio, the mixing ratio of the other resin is 100% by mass of the total amount of the methacrylic resin (I) and the other resin. It is preferable that it is 95 mass% or less, More preferably, it is 85 mass% or less, More preferably, it is 80 mass% or less, More preferably, it is 75 mass% or less.
In addition, the blending ratio in the case of blending a resin other than the acrylic resin as the other resin is relative to the total amount of 100% by mass of the above-mentioned methacrylic resin (I) and other resins other than the acrylic resin. It is preferable to make resin other than resin into 50 mass% or less. More preferably, it is 45 mass%, More preferably, it is 40 mass% or less, More preferably, it is 30 mass% or less, More preferably, it is 20 mass% or less.
In consideration of the effect of imparting properties when other resins are blended, the lower limit of the blending amount when blending other resins is preferably 0.1% by mass or more, more preferably 1% by mass or more, and Preferably it is 2 mass% or more, More preferably, it is 3 mass% or more, More preferably, it is 5 mass% or more.
The type and content of other resins can be appropriately selected according to the effects expected when used in combination with other resins.

(Additive)
A predetermined additive may be added to the film of the present embodiment in order to impart various properties such as rigidity and dimensional stability.
Examples of additives include, but are not limited to, various stabilizers such as UV absorbers, heat stabilizers, and light stabilizers; plasticizers (paraffinic process oils, naphthenic process oils, aromatics) Process oil, paraffin, organic polysiloxane, mineral oil), flame retardants (eg, phosphorus compounds such as organic phosphorus compounds, red phosphorus, inorganic phosphates, halogens, silicas, silicones, etc.), flame retardant aids (For example, antimony oxides, metal oxides, metal hydroxides, etc.), curing agents (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, 3,9-bis (3-aminopropyl) ) -2,4,8,10-tetraoxaspiro [5,5] undecane, mensendiamine, isophoro Amines such as diamine, N-aminoethylpiperazine, m-xylenediamine, m-phenylenediamine, diaminophenylmethane, diaminodiphenylsulfone, dicyandiamide, adipic dihydrazide, and phenol resins such as phenol novolac resin and cresol novolac resin , Liquid polymercaptan, polymer sulfide such as polysulfide, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, pyromellitic anhydride, methylcyclohexene Tetracarboxylic anhydride, dodecyl succinic anhydride, trimellitic anhydride, chlorendic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis Acid anhydrides such as (anhydrotrimate)), curing accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2- Heptadecylimidazole, imidazoles such as 2-phenyl-4-methylimidazole, organic phosphines such as triphenylphosphine and tributylphosphine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, 2,4,6-tris (diamino) Tertiary amines such as methyl) phenol and tetramethylhexanediamine, boron salts such as triphenylphosphine tetraphenylborate, tetraphenylphosphonium tetraphenylborate and triethylaminetetraphenylborate, 1,4-benzoyl , 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,6-dimethylbenzoquinone, quinoid compounds such as 2,3-dimethoxy-1,4-benzoquinone), antistatic agents (for example, , Polyamide elastomer, quaternary ammonium salt system, pyridine derivative, aliphatic sulfonate, aromatic sulfonate, aromatic sulfonate copolymer, sulfate ester salt, polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide , Polyalkylene glycol derivatives, betaines, imidazoline derivatives, etc.), conductivity imparting agents, stress relieving agents, mold release agents (alcohols, esters of alcohols and fatty acids, alcohols and esters of dicarboxylic acids, silicone oils, etc.), Crystallization accelerators, hydrolysis inhibitors, lubricants (eg Higher fatty acids such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and metal salts thereof, higher fatty acid amides such as ethylene bisstearamide), impact imparting agents, slidability improvers ( Hydrocarbons such as low molecular weight polyethylene, higher alcohols, polyhydric alcohols, polyglycols, polyglycerols, higher fatty acids, higher fatty acid metal salts, fatty acid amides, esters of fatty acids and fatty alcohols, full of fatty acids and polyhydric alcohols Esters or partial esters, full esters or partial esters of fatty acids and polyglycols, silicones, fluororesins, etc.), compatibilizers, nucleating agents, fillers and other reinforcing agents, flow control agents, dyes (nitroso dyes, nitro dyes) , Azo dye, stilbene azo dye, ketoimine dye, trifer Nylmethane dye, xanthene dye, acridine dye, quinoline dye, methine / polymethine dye, thiazole dye, indamine / indophenol dye, azine dye, oxazine dye, thiazine dye, sulfur dye, aminoketone / oxyketone dye, anthraquinone dye, indigoid dye, phthalocyanine Dyes such as dyes), sensitizers, colorants (titanium oxide, carbon black, titanium yellow, iron oxide pigments, ultramarine, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium pigments, etc. Pigments, azo lake pigments, benzimidazolone pigments, diarylide pigments, azo pigments such as condensed azo pigments, phthalocyanine pigments such as phthalicyanine blue and phthalocyanine green, isoindolinone pigments, quinophthalone pigments, quinacrid Pigments, perylene pigments, anthraquinone pigments, perinone pigments, organic pigments such as condensed polycyclic pigments such as dioxazine violet, flake-like aluminum metallic pigments, spherical shapes used to improve weld appearance Aluminum pigments, mica powders for pearl-like metallic pigments, other metallic pigments such as glass coated inorganic polyhedral particles such as metal plating or sputtering), thickeners, anti-settling agents, anti-sagging agents, fillers (Fibrous reinforcing agents such as glass fiber and carbon fiber, as well as glass beads, calcium carbonate, talc, clay, etc.), antifoaming agents (silicone-based antifoaming agents, surfactants, polyethers, higher alcohols, etc.) Defoaming agents, etc.), coupling agents, light diffusing fine particles, rust preventives, antibacterial / antifungal agents, antifouling agents, conductive polymers, rubber polymers, etc. It is below.

Examples of the light diffusing fine particles include, but are not limited to, inorganic fine particles such as alumina, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide, and glass beads, styrene crosslinked beads, MS crosslinked beads, and siloxane. Organic fine particles such as system cross-linked beads.
Further, hollow cross-linked fine particles made of highly transparent resin materials such as acrylic resin, polycarbonate resin, MS resin, and cyclic olefin resin, hollow fine particles made of glass, and the like can also be used as the light diffusing fine particles.
As the inorganic fine particles, alumina, titanium oxide, and the like are more preferable from the viewpoints of diffusibility and availability.
Further, the light diffusing fine particles may be used alone or in combination of two or more.
Here, the refractive index of the light diffusing fine particles is preferably 1.3 to 3.0, more preferably 1.3 to 2.5, and still more preferably 1.3 to 2.0.
When the refractive index is 1.3 or more, a practically sufficient scattering property is obtained, and when it is 3.0 or less, when the film of this embodiment is used for a member in the vicinity of the lamp, Scattering can be suppressed and the occurrence of uneven brightness and unevenness of the emitted light color tone can be effectively prevented.
The refractive index is a value at a temperature of 20 ° C. based on the D line (589 nm).
As a method for measuring the refractive index of the light diffusing fine particles, for example, immersing the light diffusing fine particles in a liquid whose refractive index can be changed little by little, and observing the interface of the light diffusing fine particles while changing the refractive index of the liquid. In addition, there is a method of measuring the refractive index of the liquid when the light diffusing fine particle interface becomes unclear. An Abbe refractometer or the like can be used to measure the refractive index of the liquid.

The average particle diameter of the light diffusing fine particles is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, still more preferably 0.3 to 10 μm, and still more preferably 0.4 to 5 μm. .
An average particle diameter of 20 μm or less is preferable because light loss due to back reflection or the like is suppressed and incident light can be efficiently diffused to the light emitting surface side. In addition, it is preferable that the average particle diameter is 0.1 μm or more because emitted light can be diffused and desired surface emission luminance and diffusibility can be obtained.

  In addition, the content of the light diffusing fine particles in the film of the present embodiment is 0.0001 to 0 with respect to 100 parts by mass of the methacrylic resin (I) from the viewpoint of the expression of the light diffusing effect and the uniformity of the surface emission. 0.03 parts by mass is preferable, and 0.0001 to 0.01 parts by mass is more preferable.

  Examples of the heat stabilizer include, but are not limited to, hindered phenol antioxidants and phosphorus antioxidants. From the viewpoint of the effect of imparting thermal stability to the resin, hindered Phenol antioxidants are preferred.

  The content of the heat stabilizer is not limited as long as the effect of improving the heat stability is obtained. If the content is excessive, problems such as bleeding out during processing may occur. It is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, and even more preferably 0 with respect to 100 parts by mass of the system resin. 0.01 parts by mass or more and 0.8 parts by mass or less, particularly preferably 0.01 parts by mass or more and less than 0.5 parts by mass.

Examples of the heat stabilizer include, but are not limited to, 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-tert-butyl-4-hydroxy-m-tolyl) propionate], hex Methylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3 , 5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1, 3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine 2-ylamine) phenol, acrylic acid 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, acrylic acid 2-tert- Butyl-4-methyl-6- (2-hydroxy-3-tert-butyl) (Lu-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 as the heat stabilizer may be a commercially available phenolic antioxidant, and such a commercially available phenolic antioxidant is limited to the following. For example, Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals), Irganox 1076 (Irganox 1076: octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, manufactured by Ciba Specialty Chemicals), Irganox 1330 (Irganox 1330: 3, 3 ′, 3 ″ 5,5 ′, 5 ″ -hexa-t-butyl-a, a ′, a ″- (Mesitylene-2,4,6-triyl) tri-p-cresol, manufactured by Ciba Specialty Chemicals), 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 Ciba Specialty Chemicals), Irganox 3125 (Irganox 3125, Ciba Specialty) Chemicals), Sumilizer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Sumilizer GS (Sumilizer GS: Acrylic acid 2 -[1- (2 -Hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl, manufactured by Sumitomo Chemical Co., Ltd., Sumilizer GM (2-tert-butyl-4-methyl acrylate) -6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl (manufactured by Sumitomo Chemical), vitamin E (manufactured by Eisai) and the like.
Among these commercially available phenolic antioxidants, Irganox 1010, Irganox 1076, Sumilizer GS, and the like are preferable from the viewpoint of imparting thermal stability with the resin. These may be used alone or in combination of two or more.

The phosphorus-based antioxidant as the heat stabilizer is not limited to the following, and examples thereof include tris (2,4-di-t-butylphenyl) phosphite and bis (2,4- Bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphos Phonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4 -Dicumylphenyl) pentaerythritol-diphosphite, tetrakis (2,4-t-butylphenyl) (1,1-biphenyl) -4,4'-diylbisphosphonate , Di-t-butyl-m-cresyl-phosphonite, 4- [3-[(2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphine Pin) -6-yloxy] propyl] -2-methyl-6-tert-butylphenol and the like.
Furthermore, a commercially available phosphorus antioxidant may be used as the phosphorus antioxidant. Examples of such commercially available phosphorus antioxidants are not limited to the following, but include Irgaphos 168 ( Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite, manufactured by Ciba Specialty Chemicals, Irgafos 12 (Irgafos 12: Tris [2-[[2,4,8,10-tetra- t-butyldibenzo [d, f] [1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals, Irgafos 38 (Irgafos 38: Bis (2 , 4-Bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid, manufactured by Ciba Specialty Chemicals) , ADK STAB 329K (ADK STAB-229K, manufactured by Asahi Denka), ADK STAB PEP36 (ADK STAB PEP36, manufactured by Asahi Denka), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka), Sandstab P-EPQ (manufactured by Clariant) , Weston 618 (Weston 618, manufactured by GE), Weston 619G (Weston 619G, manufactured by GE), Ultranox 626 (Ultranox 626, manufactured by GE), Sumilyzer GP (Sumilizer GP: 4- [3-[(2, 4, 8 , 10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepine) -6-yloxy] propyl] -2-methyl-6-tert-butylphenol (manufactured by Sumitomo Chemical) Is mentioned.
These phosphorus antioxidants may be used alone or in combination of two or more.

Moreover, in the film of this embodiment, since the methacrylic resin (I) contains the structural unit (B) having a ring structure in the main chain without using the heat stabilizer described above, the film is good. Although heat stability can be obtained, when trying to obtain more excellent heat stability, when the blending ratio of the heat stabilizer to 100 parts by mass of the methacrylic resin is (Y) / part by mass, methacrylic acid It is preferable that the ester monomer unit, the structural unit (B) having a ring structure in the main chain, and the blending ratio (Y) of the heat stabilizer satisfy the following formula (α).
(Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.4 (α)

As described above, the methacrylic resin (I) used as the film material of the present embodiment includes the structural unit (B) having a ring structure in the main chain.
By including the structural unit (B) having a ring structure in the main chain, thermal decomposition of the methacrylic resin is suppressed when the methacrylic resin is exposed to high temperature conditions such as molding, and the amount of volatile components generated The effect of reducing is obtained.
That is, by increasing the content of the structural unit (B) having a ring structure in the main chain with respect to the methacrylic ester monomer unit (A) contained in the methacrylic resin (I), The amount of heat stabilizer added can be reduced.
On the other hand, if the ratio of the methacrylic acid ester monomer unit (A) is large with respect to the content of the structural unit (B) having a ring structure in the main chain, the thermal decomposition of the methacrylic resin proceeds. In order to compensate for this, it is necessary to increase the amount of heat stabilizer added.
Specifically, methyl methacrylate (MMA) and maleimide-based structural unit (MI) shown in Examples described later are used, and MMA / MI (methacrylic acid ester-based monomer unit (A) content / (B) content And the amount of the thermal stabilizer necessary for obtaining practically excellent thermal stability, the above formula (α) was derived, and the formula (α) It was found that by applying a methacrylic resin and a heat stabilizer amount satisfying the above conditions, a particularly excellent thermal stability can be obtained in practical use.
At this time, “practically excellent thermal stability” means that the methacrylic resin decomposes when held at 270 ° C. for 30 minutes, as described in the examples described later, thereby reducing the mass. It means that the amount is 5% or less.
If a thermal stabilizer is contained so as to satisfy the above formula (α), practically excellent thermal stability can be obtained, and excessive blending of the thermal stabilizer can be suppressed.

From the viewpoint of obtaining high thermal stability, (Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.35, more preferably (Y). ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.3, more preferably (Y) ≧ 0.053 × [methacrylic acid ester monomer unit content Amount / (B) content] -0.25.
If it is the said range, the high thermal stability suitable as a film can be hold | maintained.

  In addition, in said formula ((alpha)), "methacrylic acid ester monomer unit content" means a methacrylic acid ester, when the methacrylic resin which comprises the film of this embodiment is only methacrylic resin (I). It is equal to the content of the monomer (A). On the other hand, when an acrylic resin is contained as the other resin described above, the methacrylic acid ester monomer contained in the acrylic resin is also included in the “methacrylic acid ester monomer unit content”.

Examples of the ultraviolet absorber include, but are not limited to, for example, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, Examples include malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, and benzoxazinone compounds.
In particular, from the viewpoint of compatibility with the resin, benzotriazole compounds and benzotriazine compounds are preferable. These may be used alone or in combination of two or more.
The ultraviolet absorber preferably has a vapor pressure (P) at 20 ° C. of 1.0 × 10 ⁻⁴ Pa or less from the viewpoint of ensuring good moldability of the film of the present embodiment, and 1.0 × It is more preferably 10 ⁻⁶ Pa or less, and further preferably 1.0 × 10 ⁻⁸ Pa or less.
Here, good moldability means that, for example, when a film is formed, there is little adhesion of a low molecular compound to a roll. When it adheres to the roll, it re-adheres to the surface, which causes the appearance to deteriorate and the optical properties to deteriorate, so satisfy the above vapor pressure (P) value and obtain good moldability. Is preferred.

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 reduction rate of 50% or less, more preferably 30% or less, and more preferably 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, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 1 part by mass with respect to 100 parts by mass of the methacrylic resin. Hereinafter, it is still more preferably 0.8 parts by mass or less, and still more preferably 0.01 parts by mass or more and 0.8 parts by mass or less.

[Method for producing film]
As described above, the film of this embodiment contains a methacrylic resin (I) and a rubbery polymer (II), and contains various additives and other resins as necessary.
In order to manufacture the film of this embodiment, first, a predetermined material is mixed, a methacrylic resin composition is manufactured, and it shape | molds using the said methacrylic resin composition.
Examples of the method for producing a methacrylic resin composition include a method of kneading using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, and a Banbury mixer.
Among these, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the polymer constituting the methacrylic resin and other resins to be mixed, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C.

As a method for producing the film, known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, etc. can be applied. Secondary processing molding methods such as vacuum molding can also be used.
A method of kneading and producing a methacrylic resin composition using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., cooling, pulverizing, and further molding by transfer molding, injection molding, compression molding, etc. Can also be cited as an example.
After the molding, the film may be longitudinally uniaxially stretched in the mechanical flow direction, transversely uniaxially stretched in the direction orthogonal to the mechanical flow direction, or a simultaneous biaxial stretching method of roll stretching and tenter stretching, and simultaneous tenter stretching. A biaxially stretched film may be produced by stretching by a biaxial stretching method, a biaxial stretching method by tubular stretching, or the like. By stretching, the strength of the film can be improved. The final draw ratio can be determined from the heat shrinkage rate of the obtained molded body. The draw ratio is preferably 0.1% or more and less than 300% in at least one direction, more preferably 0.2% or more and 300% or less, and 0.3% or more and 300% or less. Further preferred. By designing in this range, a stretched molded article that is preferable in terms of birefringence, heat resistance, and strength can be obtained.
The film can be stretched continuously by extrusion molding and cast molding. 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 conditions for the heat treatment may be appropriately selected similarly to the conditions for the heat treatment performed on a conventionally known stretched film, and are not particularly limited.

  The film thickness of the film of the present embodiment is preferably 0.01 mm or more and 1 mm or less, more preferably 0.01 mm or more and 0.5 mm or less, more preferably 0 in consideration of optical characteristics, strength, and handleability. It is 0.01 mm or more and 0.3 mm or less, still more preferably 0.02 mm or more and 0.2 mm or less, and still more preferably 0.02 mm or more and 0.1 mm or more.

[Characteristics as a film]
The film of this embodiment may be exposed to high-temperature and high-humidity conditions in optical film applications, decorative film applications, and the like, and excellent moisture and heat resistance is required.
In addition, thinning is required due to the demand for weight reduction, and accordingly, higher thermal stability and moldability are required.

(Heat-resistant)
As a heat resistance index, VICAT softening temperature can be used.
The VICAT softening temperature of the molded body of the resin composition forming the film of the present embodiment is preferably 110 ° C. or higher from the viewpoint of suppressing problems such as distortion during actual use. More preferably, it is 112 degreeC or more, More preferably, it is 113 degreeC or more, More preferably, it is 115 degreeC or more, More preferably, it is 117 degreeC or more, Most preferably, it is 120 degreeC or more.
The VICAT softening temperature can be measured according to ISO 306 B50, and specifically, can be measured by the method described in Examples described later.

(transparency)
The total light transmittance can be used as an index of transparency.
The total light transmittance in the film of the present embodiment may be appropriately optimized depending on the application, but when used in applications where transparency is required, the total light transmittance at a thickness of 200 μm is used from the viewpoint of visibility. Is preferably 70% or more. More preferably, it is 75% or more, More preferably, it is 80% or more.
Although it is preferable that the total light transmittance is high, practically sufficient visibility can be secured even at 94% or less.
The total light transmittance can be measured, for example, by the method of the following example.

(Moisture and heat resistance)
As an index of heat and humidity resistance, evaluation of the state of occurrence of defective shape under high temperature and humidity conditions can be used.
When using the film of this embodiment, it may be put on hot and humid conditions.
When the film of this embodiment is left as it is for about 500 hours at a set temperature of 70 ° C. and a set humidity of 95% using a film having a thickness of about 0.2 mm as an evaluation of moisture and heat resistance, defects such as warping and distortion are found. Preferably it does not occur.

(Scratch resistance)
Pencil hardness can be used as an index of scratch resistance.
The film of this embodiment preferably has a pencil hardness of HB or higher as the surface hardness in order to prevent scratching of the surface during handling. More preferably, it is F or more, more preferably H or more.
Specifically, the scratch resistance of the film can be evaluated by the method described in Examples described later.

(Molding processability)
As an index of moldability, fluidity and the presence or absence of bubbles can be used as indices.
The film of the present embodiment is required to be thin in order to reduce the weight, but in order to reduce the thickness, it is effective to increase the molding temperature and improve the fluidity. On the other hand, if the molding temperature is raised, bubbles may be generated in the film due to decomposition of the resin or the like.
Even in the case where the film of this embodiment is molded by raising the molding temperature in order to eliminate molding distortion or to obtain a thin film, it is preferable that defects such as silver do not occur.
Specifically, it is preferable that molding defects such as bubble generation are hardly observed when a film having a barrel temperature of 280 ° C. and a thickness of about 80 μm is molded.
Specifically, the moldability can be evaluated by the method described in Examples described later.

(Thermal stability)
As a thermal stability index, a weight reduction ratio when held at a predetermined temperature for a predetermined time and a thermal decomposition start temperature can be used.
When manufacturing the film of this embodiment, resin may remain in a molten state in a molding machine. At that time, since the resin stays at a high temperature for a long time, the resin material is required to be hardly thermally decomposed.

Specifically, in TGA (Thermogravimetric Analysis), the weight loss rate when held at about 270 ° C. for 30 minutes is preferably 5% or less, more preferably 3% or less, still more preferably 1% or less, More preferably, it is 0.5% or less.
About the thermal decomposition amount at the time of holding | maintenance of 270 degreeC / 30 minutes, it can measure by the method described in the Example mentioned later.

When it is necessary to make the film of this embodiment thin, it is necessary to perform molding at a high temperature, and high thermal stability is required.
From this viewpoint, the thermal decomposition starting temperature of the methacrylic resin or methacrylic resin composition is preferably 300 ° C. or higher. More preferably, it is 310 degreeC or more, More preferably, it is 320 degreeC or more, More preferably, it is 325 degreeC or more, More preferably, it is 330 degreeC or more.
Specifically, the thermal decomposition start temperature can be measured by the method described in the examples described later.

As described above, in order to prevent thermal decomposition and have practically excellent thermal stability in the film forming process of the present embodiment, a methacrylic resin (I ), It is effective to increase the proportion of the structural unit (B) having a ring structure in the main chain and relatively reduce the amount of copolymerization of the methacrylic ester monomer unit (A).
However, if the ratio of the component (B) to the methacrylic acid ester monomer unit (A) is too high, characteristics such as molding fluidity and surface hardness required as a film may not be obtained. In consideration of the balance, it is necessary to determine the ratio of the component (A) and the component (B).
Increasing the copolymerization ratio of the structural unit (B) having a ring structure in the main chain is effective in terms of suppressing a decomposition reaction due to depolymerization when exposed to a high temperature. When the ratio with respect to the ester monomer unit (A) is increased, sufficient thermal stability can be imparted even if the amount of the thermal stabilizer is reduced.
On the other hand, if the proportion of the methacrylic ester monomer unit (A) is relatively large, the amount of thermal decomposition in a high temperature environment increases. A heat stabilizer may be added from the viewpoint of suppressing thermal decomposition, but adding too much may cause a decrease in heat resistance and may cause problems such as bleeding out during molding.

In order to obtain the characteristics required as a film, as described above, when the blending ratio of the thermal stabilizer to 100 parts by mass of the methacrylic resin is (Y: parts by mass), thermal decomposition is suppressed and molded at high temperatures. From the viewpoint of balance between processability and heat resistance, it is preferable that the blending ratio of the methacrylic acid ester monomer unit, the structural unit (B) having a ring structure in the main chain, and the thermal stabilizer satisfies the following formula (α). .
(Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.4 (α)
More preferably, (Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.35, and further preferably (Y) ≧ 0.053 × [methacrylic acid ester. Monomer unit content / (B) content] −0.3, and even more preferably (Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] − 0.27, more preferably (Y) ≧ 0.053 × [methacrylic acid ester monomer unit content / (B) content] −0.25.

(Impact resistance)
As an index of impact resistance, Charpy impact strength can be used.
The film of this embodiment may be required to have high impact strength.
Specifically, the Charpy impact strength (without notch) measured in accordance with the IOS 179 / 1eU standard is preferably 15 kJ / m ² or more. More preferably 15 kJ / m ² or more 20 kJ / m less than ^2, more preferably 20 kJ / m ² or more 25 kJ / m less than ^2, particularly preferably 25 kJ / m ² or more.

[Use]
The film of this embodiment is, for example, a polarizing plate protective film, a quarter-wave plate, a half-wave plate, etc. 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. It can be suitably used for liquid crystal optical compensation films such as retardation plates and viewing angle control films, display front plates, display substrates, transparent substrates such as touch panels, and decorative film applications.
The film of the present invention can be subjected to surface functionalization treatment such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

  Hereinafter, although a specific Example and a comparative example are given and demonstrated, this invention is not limited to these.

〔material〕
It shows below about the raw material used in the Example and comparative example which are mentioned later.
(A) component:
(A-1): Methyl methacrylate (MMA)
: Asahi Kasei Chemicals Co., Ltd. (2.5 ppm of 2,4-di-6-tert-butylphenol as a polymerization inhibitor, manufactured by Chugai Trading Co., Ltd.) Added)
(A-2): cyclohexyl methacrylate: manufactured by Asahi Kasei Chemicals Corporation (A-3): phenyl methacrylate: manufactured by Wako Pure Chemical Industries, Ltd.

(B) component:
(B-1): N-phenylmaleimide (NPMI)
: Nippon Shokubai Co., Ltd. (B-2): N-cyclohexylmaleimide (NCyMI)
: Nippon Catalyst Co., Ltd.

(C) component:
(C-1): Styrene (St)
: Asahi Kasei Chemicals Corporation (C-2-1): Methyl acrylate (MA)
: Made by Mitsubishi Chemical Corporation (14-ppm of 4-methoxyphenol made by Kawaguchi Chemical Industry is added as a polymerization inhibitor)
(C-2-2): Ethyl acrylate (EA)
: Made by Mitsubishi Chemical Corporation (C-3): Acrylonitrile (AN)
: Asahi Kasei Chemicals Corporation

(D) component:
(D-1): Maleic anhydride (MAH)
: Mitsui Chemicals, Inc.

(Other ingredients):
n-octylmercaptan (NOM)
: Arkema Co., Ltd., used as a chain transfer agent Lauroyl peroxide (LPO)
: Nippon Oil & Fats Co., Ltd., used as a polymerization initiator Tricalcium phosphate
: Nihon Kagaku Kogyo Co., Ltd., used as a suspending agent Calcium calbonate
: Shiraishi Kogyo Co., Ltd., used as a suspending agent Sodium lauryl sulfate
: Wako Pure Chemical Industries, Ltd., used as a suspension aid
2- (2-Hydroxy-5-methylphenyl) benzotriazole (2- (2H-Benzotriazol-2-yl) -p-cresol
： Johoku Chemical Co., Ltd. JF77, used as UV absorber

[Measurement method]
(I. Molecular weight measurement of methacrylic resin)
The weight average molecular weight of the methacrylic resin was measured with the following apparatus and conditions.
Measuring apparatus: Gel permeation chromatography (HLC-8320GPC) manufactured by Tosoh Corporation Column: One TSKguardcolumn SuperH-H, two TSKgel SuperHM-M, and one TSKgel SuperH2500 were connected in series in this order.
In this column, the high molecular weight elutes early and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 3.0 mV / min
Column temperature: 40 ° C
Sample: 0.02 g of methacrylic resin in 20 mL of tetrahydrofuran Injection amount: 10 μL
Developing solvent: Tetrahydrofuran, flow rate: 0.6 mL / min, 0.1 g / L of 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard.
The following 10 polymethyl methacrylates (manufactured by Polymer Laboratories; PMMA Calibration Kit M-M-10) having different molecular weights and known monodisperse weight peak molecular weights were used as standard samples for calibration curves.
Weight peak molecular weight (Mp)
Standard sample 1 1,916,000
Standard sample 2 625,500
Standard sample 3 298,900
Standard sample 4 138,600
Standard sample 5 60,150
Standard sample 6 27,600
Standard sample 7 10,290
Standard sample 85,000
Standard sample 9 2,810
Standard document 10 850
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
The weight average molecular weight (Mw) of the methacrylic resin was determined based on the area area in the GPC elution curve and a calibration curve of a seventh-order approximation.

(II. Measurement of residual monomer amount)
The amount of residual monomer contained in the resin compositions produced in Examples and Comparative Examples described later was measured under the following conditions and apparatus.
Sample: <1. Heat resistance; measurement of VICAT softening temperature> The 4 mm-thick test piece produced in the above was cut to obtain a sample for measuring the residual monomer amount.
Measuring device: GC-1700 manufactured by Shimadzu Corporation
Column used: TC-1 φ0.32mm × 30m × 0.25μm
Carrier gas: Nitrogen (1.3mL / min)
Split ratio: (1: 5)
Linear velocity: 23 cm / sec
Column pressure 42 kPa
Total flow rate 11mL / min
Injection volume 0.8μL
Set temperature INJ / DET = 230 ℃ / 300 ℃
Temperature increase program 45 ° C. (held for 5 minutes) → Temperature increased to 90 ° C. at 10 ° C./min. → The temperature was raised to 190 ° C at 30 ° C / min. → The temperature was raised to 220 ° C at 10 ° C / min. → The temperature was raised to 300 ° C at 50 ° C / min.
The residual monomer amount was calculated using a calibration curve prepared in advance for the monomer species to be measured.
In Table 3, “MI residual monomer amount” represents the total residual amount of maleimide monomer used as component (B).

(III. Measurement of average particle diameter of rubbery polymer)
The emulsion of rubber-containing copolymer particles was sampled, diluted with water to a solid content of 500 ppm, and the absorbance at a wavelength of 550 nm was measured using a UV1200V spectrophotometer (manufactured by Shimadzu Corporation). .
From this measured value, the average particle size was determined using a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle size was measured from a transmission electron micrograph.

(IV. Physical property measurement)
<1. Heat resistance; VICAT softening temperature measurement>
In accordance with ISO 306 B50, measurement was performed using a 4 mm-thick test piece to obtain a VICAT softening temperature (° C.), which was used as an index for heat resistance evaluation.

<2. Moist heat resistance test>
Using a IS-100EN injection molding machine manufactured by Toshiba Machine Co., Ltd., a test piece having a thickness of 3 mm, a width of 100 mm and a length of 100 mm was produced at a molding temperature of 270 ° C. and a mold temperature of 60 ° C., and a temperature of 70 ° C. and a humidity of 95 The shape of the test piece after being left in a constant temperature and humidity chamber set at% for 500 hours was observed and evaluated according to the following criteria.
Deformation such as distortion: “×”
Slightly deformed: “△”
Almost no deformation: “○”

<3. Moldability 1: Fluidity during molding>
Using an IS-100EN injection molding machine manufactured by Toshiba Machine Co., Ltd., a molding temperature of 250 ° C., a mold temperature of 60 ° C., an injection pressure of 56 MPa, an injection time of 20 seconds, and a cooling time of 40 seconds, a thickness of about 3.2 mm × width A test piece of about 12.7 mm × length of about 127 mm was manufactured by injection molding and evaluated according to the following criteria.
Samples obtained: "○"
Short shot due to poor fluidity: “×”

<4. Molding processability 2: presence or absence of bubbles>
A film having a film thickness of about 50 μm was produced at a set temperature of 280 ° C.
A film with a large amount of bubbles was evaluated as “×”, a film with a small amount of bubbles was evaluated as “Δ”, and a film with almost no bubbles was evaluated as “◯”.

<5. Thermal stability evaluation>
(1% weight loss temperature)
Measurement was carried out under the following apparatus and conditions, and the temperature when the weight decreased by 1% was calculated and used as the thermal decomposition start temperature.
Measuring apparatus: differential type differential thermal balance Thermo plus EVO II TG8120 (manufactured by Rigaku Corporation)
Sample preparation: <3. Formability 1: Flowability at the time of molding> Similar to the method for producing a test piece, a test piece having a thickness of about 3 mm, a width of about 40 mm, and a length of about 60 mm is manufactured and the test piece is cut. The following measurement sample of about 10 mg was obtained.
Sample amount: about 10mg
Measurement atmosphere: Nitrogen (100 mL / min)
Measurement conditions: held at 100 ° C./5 min. → The temperature was raised to 400 ° C. at 10 ° C./min, and the point at which 1% weight was reduced was measured to obtain the thermal decomposition starting temperature (1% weight reduction temperature).
(Decomposition amount at 270 ° C / 30 minutes holding)
Moreover, the measurement was performed under the following setting conditions, and the weight reduction ratio (%) when held at about 270 ° C. for 30 minutes was calculated.
Measuring apparatus: differential type differential thermal balance Thermo plus EVO II TG8120 (manufactured by Rigaku Corporation)
Sample amount: about 10mg
Measurement atmosphere: Nitrogen (100 mL / min)
The temperature was maintained at 50 ° C./2 min. → The temperature was raised to 200 ° C at 20 ° C / min. → The temperature was raised to 250 ° C at 20 ° C / min. → The temperature was raised to a set temperature of 265 ° C. at 10 ° C./min, held for 60 minutes, and the weight loss rate after 30 minutes from the start of the holding was calculated. The measurement temperature was about 270 ° C. at the set temperature of 265 ° C.

<6. Measurement of pencil hardness>
Using an IS-75S injection molding machine manufactured by Toshiba Machine Co., Ltd., a test piece having a thickness of about 3 mm, a width of about 40 mm, and a length of about 60 mm was produced at a molding temperature of 270 ° C. and a mold temperature of 60 ° C. After drying in an oven for 10 hours, the measurement was performed in accordance with the conditions of JIS-K-5600-5-4.

<7. Impact resistance evaluation-Charpy impact strength (no notch)>
Measurement was performed in accordance with the ISO 179 / 1eU standard, and evaluation was performed according to the following criteria.
“◯”: 25 kJ / m ² or more “△”: 20 kJ / m ² or more and less than 25 kJ / m ² “×”: Less than ²⁰ kJ / m ²

<8. Evaluation of film winding property>
A film having a thickness of 50 μm was formed.
In the film winding device, the evaluation of the adhesion state between the films was evaluated by the following ○, Δ, and ×.
○: The film can be wound up without being twisted without being in close contact with each other.
Δ: A state in which the films are partly in close contact with each other but does not lead to breakage.
X: The films are in close contact with each other and may eventually break.

<9. Overall evaluation>
In the said evaluation, what was judged suitable for a film use was set to "(circle)", and what was judged to be unsuitable for a film use by having shown a defect in any was set to "x".

Hereinafter, the manufacturing method of methacrylic resin (I) is shown.
The raw materials and blending amounts are shown in Table 1 below.
Table 2 below shows the monomer charge composition.

[Production Example 1]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was charged into a 60 L reactor equipped with a stirrer equipped with three blades and the temperature was raised to 40 ° C., and the mixture (a) and the blending amount shown in Table 1 below were shown in Table 2. Raw materials for methacrylic resin were added at a blending ratio.
Next, the temperature was raised to 75 ° C. at a rate of about 1 ° C./min, suspension polymerization was carried out while maintaining about 75 ° C., and an exothermic peak was observed about 150 minutes after the starting material mixture was charged.
Thereafter, the temperature was raised to about 96 ° C. at a rate of about 1 ° C./min, and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Next, the polymerization reaction solution is passed through a 1.68 mm mesh sieve to remove aggregates, the water is filtered off, the resulting slurry is dehydrated to obtain a bead polymer, and the resulting bead polymer is After washing with water, it was dehydrated in the same manner as described above, and further washed with ion-exchanged water and repeated dehydration to obtain polymer particles.
The polymer particles obtained and 500 mass ppm of 2- (2-hydroxy-5-methylphenyl) benzotriazole were melt-kneaded in a φ30 mm twin-screw extruder set at 240 ° C., and the strand was cooled and methacrylic. Resin pellets were obtained. It was confirmed that the extrusion workability at that time was good.

[Production Examples 2 to 9, Comparative Production Examples 1 to 4]
Polymerization was performed using the raw materials shown in Table 1 below in the same manner as in Production Example 1 to obtain polymer particles.
The obtained polymer particles were melt-kneaded with a φ30 mm twin-screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets. It was confirmed that the extrusion workability at that time was good.

[Comparative Production Example 5]
Polymerization was performed using the raw materials shown in Table 1 below in the same manner as in Example 1 to obtain polymer particles.
The obtained polymer particles were melt-kneaded with a φ30 mm twin-screw extruder set at 260 ° C., and the strands were cooled and cut to obtain resin pellets. It was confirmed that the extrusion workability at that time was good.

[Comparative Production Example 6]
Using a container equipped with a stirrer, 78 parts by weight of methyl methacrylate, 16 parts by weight of styrene, 12 parts by weight of maleic anhydride, 0.03 parts by weight of lauroyl peroxide and 0.23 parts by weight of n-octyl mercaptan The parts were mixed and dissolved to prepare a monomer compounding solution.
On the other hand, two glass plates having a size of 250 × 300 mm and a thickness of 6 mm are used, and the vicinity of the outer periphery is bonded with a flexible vinyl chloride gasket, and the distance between the two glass plates is 3.5 mm. A cell was prepared and prepared.
A devolatilization operation for 2 minutes was performed while stirring the monomer blend solution described above under a reduced pressure of 50 torr. Thereafter, the reduced pressure was released and the pressure was returned to normal pressure, and immediately filled into the glass cell.
Next, it is kept in a hot water tank adjusted to 60 to 65 ° C. for 22 hours, and then kept in a hot-air circulating oven adjusted to 110 ° C. for 3 hours, and then allowed to stand and cool indoors to remove the glass plate. A sheet-like resin was obtained.
The sheet-like resin obtained as described above was pulverized with a coarse pulverizer Orient Mill VM-42D machine manufactured by Seishin Enterprise Co., Ltd. equipped with a 10 mm mesh net, and then the pulverized product was passed through a 500 μm sieve, Fine powder was removed to obtain a pulverized composition.
The recovery rate of the pulverized composition was 93.2%.
The obtained pulverized composition was melt-kneaded with a φ30 mm twin-screw extruder set at 240 ° C., and the strand was cooled and cut to obtain resin pellets.
It was confirmed that the extrusion workability at that time was good.

[Rubber polymer (II)]
A rubbery polymer (II) was produced according to <Production Example 10> to <Production Example 12> described later.
The methacrylic resin (I) produced in Production Examples 1 to 9 and Comparative Production Examples 1 to 6 described above, and the rubbery polymer (II) produced by <Production Example 10> to <Production Example 12> described later. The resin compositions and molded articles of Examples and Comparative Examples described later in combination were produced, and the above physical properties were evaluated.

The abbreviations shown in the method for producing rubbery polymer (II) described later indicate the following compounds.
MMA: methyl methacrylate BA: n-butyl acrylate St: styrene MA: methyl acrylate ALMA: allyl methacrylate PEGDA: polyethylene glycol diacrylate (molecular weight 200)
DPBHP: Diisopropylbenzene hydroperoxide n-OM: n-octyl mercaptan

<Production Example 10>
(Rubber polymer having a three-layer structure (II-1))
A reactor with an internal volume of 10 L equipped with a reflux condenser was charged with 4600 mL of ion-exchanged water and 24 g of sodium dioctylsulfosuccinate as an emulsifier, and the temperature was raised to 80 ° C. in a nitrogen atmosphere while stirring at 250 rpm. Was virtually absent (substantially oxygen-free).
Next, Rongalite l. 2 g was added and dissolved uniformly.
As a first layer, a monomer mixture of MMA 150 g, BA 2.5 g, St 40 g, ALMA 0.2 g, and DPBHP 0.2 g was added and polymerized at 80 ° C. The reaction was complete in about 15 minutes.
Next, as a second layer, a monomer mixture of BA 1110 g, St572 g, PEGDA 40 g, ALMA 7.0 g, DPBHP 3.5 g and Rongalite 2.0 g was added dropwise over 90 minutes. The reaction was completed 60 minutes after the completion of the dropwise addition.
Next, a monomer mixture of 190 g of MMA, 2.0 g of BA, 0.2 g of DPBHP, and 0.1 g of n-OM was dropped over 5 minutes as the third layer, and after completion of the dropping, the reaction at this stage was completed in about 15 minutes. .
Finally, a monomer mixture of MMA 380 g, BA 2.5 g, DPBHP 0.4 g, and n-OM 1.2 g was added as the third layer two steps over 10 minutes. This step was complete in about 15 minutes.
The temperature is raised to 95 ° C. and held for 1 hour, and the resulting emulsion is poured into a 0.5% aluminum chloride aqueous solution to agglomerate the polymer, washed 5 times with warm water, dried and dried in a white floc form. Obtained material.
The first layer corresponds to the innermost layer, the second layer corresponds to the intermediate layer, and the third layer corresponds to the outermost layer.
A small amount of the polymer emulsion thus obtained was collected, and the average particle size was determined by the method (III. Measurement of average particle size of rubbery polymer) in the method for measuring physical properties, and found to be 0.1 μm. It was.

<Production Example 11>
(Rubber polymer having a three-layer structure (II-2))
Ion exchange water 4600mL and sodium dioctylsulfosuccinate 33g are put into a reactor with a reflux condenser with an internal volume of 10L, and the temperature is raised to 80 ° C under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. It was in a state where there was no top (substantially oxygen-free state).
Five minutes after adding 1.0 g of sodium formaldehyde sulfoxylate, 30% by mass of a monomer mixture consisting of MMA 220 g, BA 3.5 g, St 48 g, ALMA 0.27 g and DPBHP 0.27 g was added all at once. The remaining 70% by mass was continuously added over 20 minutes, and after completion of the addition, the mixture was further maintained for 60 minutes to complete the polymerization of the innermost layer.
Next, 5 minutes after adding 0.8 g of sodium formaldehyde sulfoxylate, a monomer mixture consisting of BA620 g, St325 g, ALMA 14 g, tetraethylene glycol diacrylate 4.8 g and DPBHP 2.0 g was continuously added over 60 minutes. After completion of the addition, the mixture was held for another 80 minutes to complete the polymerization of the soft layer (intermediate layer).
Next, a monomer mixture composed of MMA 760 g, BA 50 g, DPBHP 1.6 g and n-OM 1.0 g was continuously added over 70 minutes, and the mixture was held for 60 minutes after the addition was completed.
Next, the temperature was raised to 95 ° C. and held for 60 minutes to complete the polymerization of the outermost layer.
A small amount of the polymer emulsion thus obtained was collected, and the average particle size was determined by the method (III. Measurement of average particle size of rubbery polymer) in the method for measuring physical properties, and found to be 0.09 μm. It was.
The remaining emulsified liquid is poured into a 3% by mass aqueous sodium sulfate solution for salting out and coagulation. Next, after repeated dehydration and washing, a drying treatment is performed to obtain a rubber polymer (II-2). Obtained as a powder.

<Production Example 12>
(Rubber polymer having a three-layer structure (II-3))
Ion exchange water 5600mL and sodium dioctylsulfosuccinate 40g were put into a reactor with a reflux condenser with an internal volume of 10L, and the temperature was raised to 80 ° C under a nitrogen atmosphere while stirring at 250 rpm. It was in a state where there was no top (substantially oxygen-free state).
5 minutes after adding 1.2 g of sodium formaldehyde sulfoxylate, 30% by mass of a monomer mixture consisting of 260 g of MMA, 4.2 g of BA, St64 g, 0.33 g of ALMA and 0.33 g of DPBHP was added all at once. The remaining 70% by mass was continuously added over 20 minutes, and after completion of the addition, the mixture was further maintained for 60 minutes to complete the polymerization of the innermost layer.
Next, 5 minutes after adding 1.0 g of sodium formaldehyde sulfoxylate, a monomer mixture consisting of 917 g of BA, St 480 g of St, ALMA 21 g, 7.0 g of tetraethylene glycol diacrylate and 2.9 g of DPBHP was added over 90 minutes. The mixture was continuously added and maintained for 80 minutes after the addition was completed to complete the polymerization of the soft layer (intermediate layer).
Next, a monomer mixture composed of MMA 695 g, BA 45 g, DPBHP 1.47 g and n-OM 0.9 g was continuously added over 60 minutes, and the mixture was held for 60 minutes after the addition was completed.
Next, the temperature was raised to 95 ° C. and held for 60 minutes to complete the polymerization of the outermost layer.
A small amount of the polymer emulsion thus obtained was collected, and the average particle size was determined by the method (III. Measurement of average particle size of rubbery polymer) in the method for measuring physical properties, and found to be 0.08 μm. It was.
The remaining emulsified liquid was poured into a 3% by mass sodium sulfate warm aqueous solution, salted out and coagulated, and then dried after repeated dehydration and washing to obtain a rubbery polymer (II-3) as a powder. .

[Reference Examples 1, 2, Example 3, Reference Example 4, Examples 5-8, Reference Example 9] , [Comparative Examples 1-6]
Using the methacrylic resins obtained in Production Examples 1 to 9 and Comparative Production Examples 1 to 6 and the rubbery polymer obtained in Production Examples 10 to 12, the strands were cooled by kneading with a φ30 mm twin screw extruder. The resin composition pellet was obtained by cutting.
Using the obtained resin composition pellets, a molded body was produced, and the physical properties were evaluated.
The evaluation results are shown in Table 3 below.

As shown in Table 3 below, Reference Examples 1, 2, Example 3, Reference Example 4, Examples 5-8, and Reference Example 9 have high heat resistance, moist heat resistance, thermal stability, and moldability. In addition, a film containing a methacrylic resin having excellent mechanical strength in practical use was obtained.

  The present invention relates to a polarizing plate protective film 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, a retardation plate such as a quarter-wave plate and a half-wave plate, a visual field It has industrial applicability as a liquid crystal optical compensation film such as a corner control film, a display front plate, a display substrate, a transparent substrate such as a touch panel, and a decorative film.

Claims (8)

Methacrylic acid ester monomer unit (A): 50 to 97% by mass;
A structural unit (B) comprising a maleimide structural unit (B-1) and having a ring structure in the main chain: 3% by mass or more and less than 15% by mass ;
When the total amount of the component (A) and the component (B) is 100 parts by mass, the aromatic vinyl monomer unit (C-1) is 5.38 parts by mass to 10 parts by mass. Including
100 parts by weight of methacrylic resin (I) satisfying the following conditions (i) and (ii);
1 to 100 parts by mass of rubbery polymer (II),
A film containing
A film in which the amount of maleimide-based residual monomer in the film is 0.01% by mass or more and 0.5% by mass or less.
(I) The weight average molecular weight measured by gel permeation chromatography (GPC) is 650,000 to 300,000.
(Ii) When the total amount of the component (B −1 ) and the component (C −1 ) is 100% by mass, the mass ratio satisfies the following formula .
0.3 ≦ (C-1) / (B-1) ≦ 1 The film according to claim 1, wherein the rubbery polymer (II) has an average particle size of 0.03 µm or more and 1 µm or less. The film according to claim 1 or 2 , wherein the structural unit (B) having a ring structure in the main chain includes an N-cyclohexylmaleimide structural unit and / or an N-aryl group-substituted maleimide structural unit. The film according to any one of claims 1 to 3 , wherein the structural unit (B) having a ring structure in the main chain includes an N-aryl group-substituted maleimide-based structural unit. The film as described in any one of Claims 1 thru | or 4 which further contains 0 mass part-5 mass parts of ultraviolet absorbers with respect to 100 mass parts of said methacrylic resins (I). The film as described in any one of Claims 1 thru | or 5 whose Vicat softening temperature measured using the molded object containing the said methacrylic resin (I) and rubber-like polymer (II) is 110 degreeC or more. The film as described in any one of Claims 1 thru | or 6 whose thickness of a film is 0.01-1 mm. The film according to any one of claims 1 to 7 , wherein, in TGA (Thermogravimetric Analysis), the weight reduction ratio after heating for 0.5 hours at a heating temperature of about 270 ° C is 5% or less.