WO2017077908A1

WO2017077908A1 - Acrylic resin composition

Info

Publication number: WO2017077908A1
Application number: PCT/JP2016/081638
Authority: WO
Inventors: 奈緒子師井; 赤石　聡
Original assignee: 住友化学株式会社
Priority date: 2015-11-06
Filing date: 2016-10-25
Publication date: 2017-05-11
Also published as: JPWO2017077908A1

Abstract

The present invention is an acrylic resin composition comprising a copolymer (1) and a polymer (2). The copolymer (1) is a copolymer that includes a structural unit represented by formula (1a) and a structural unit represented by formula (1b), and that includes 5-70 mass% of the structural unit represented by said formula (1a) and 30-95 mass% of the structural unit represented by said formula (1b) with respect to all of the structural units included in said copolymer (1). The polymer (2) is a polymer including a structural unit represented by formula (2a) (wherein the amount of the structural unit represented by said formula (1a) is less than 5 mass% with respect to all of the structural units included in said polymer (2)). The acrylic resin composition includes 1-90 parts by mass of said copolymer (1) and 10-99 parts by mass of said polymer (2) per 100 parts by mass in total of said copolymer (1) and said polymer (2).

Description

Acrylic resin composition

The present invention relates to an acrylic resin composition. Moreover, this invention relates also to the acrylic resin film containing this acrylic resin composition, and the polarizing plate containing this acrylic resin film.

Since the acrylic resin composition is excellent in transparency, it is widely used as a material for optical films such as a transparent protective film constituting a polarizing plate, for example. In the past, acrylic resin compositions used for such applications have been required to have improved impact resistance, and acrylic resin compositions having improved impact resistance have been proposed. For example, Patent Documents 1 and 2 describe the impact resistance of a film formed from such a resin by blending rubber elastic particles with a copolymer of methyl methacrylate and n-butyl acrylate or methyl acrylate alone. It describes that it can improve the property and film forming property.

JP 63-077963 A JP 2012-018383 A

However, when rubber elastic particles are blended with the above copolymer alone, the impact resistance of the resulting film is improved, but when the amount of rubber elastic particles necessary to obtain sufficient impact resistance is blended However, there is a problem that the elastic modulus of the film formed from such a resin is lowered.

An object of the present invention is to provide an acrylic resin composition having high impact resistance without lowering the elastic modulus.

The present invention provides the following preferred embodiments.
[1] An acrylic resin composition comprising a copolymer (1) and a polymer (2),
The copolymer (1) is a structural unit represented by the following formula (1a):

[Wherein R ¹¹ represents a hydrogen atom or a methyl group, R ¹² represents a terminal group, and X represents a formula (1a-1):

(Wherein R ¹³ is a hydrogen atom or a methyl group, and R ¹⁴ is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or An aryl group having 6 to 18 carbon atoms, and n is a number average value of 70 or more)
Or a divalent residue represented by the formula (1a-2):

(Where m is a number from 10 to 1000 as a number average value)
It is a divalent residue represented by
And a structural unit represented by the following formula (1b):

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group, and R ¹⁶ represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or It is an aryl group having 6 to 18 carbon atoms.]
Including
5 to 70% by mass of the structural unit represented by the formula (1a) and 30 to 95% by mass of the structural unit represented by the formula (1b) with respect to all the structural units contained in the copolymer (1). A copolymer,
The polymer (2) is a structural unit represented by the following formula (2a):

[Wherein R ²¹ represents a hydrogen atom or a methyl group, and R ²² represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or It is an aryl group having 6 to 18 carbon atoms.]
(However, the structural unit represented by the formula (1a) is less than 5% by mass with respect to all the structural units contained in the polymer (2)),
Acrylic resin composition comprising 1 to 90 parts by mass of copolymer (1) and 10 to 99 parts by mass of polymer (2) with respect to 100 parts by mass in total of copolymer (1) and polymer (2) object.
[2] X in the formula (1a) is a divalent residue represented by the formula (1a-1), and is represented by the formula (1a) for all structural units contained in the copolymer (1). The amount of the structural unit is 5 to 15% by mass, and 10 to 30 parts by mass of the copolymer (1) and the polymer (100% relative to the total of 100 parts by mass of the copolymer (1) and the polymer (2)). The acrylic resin composition according to the above [1], comprising 70 to 90 parts by mass of 2).
[3] The acrylic resin according to [1] or [2], comprising 1 to 50 parts by mass of rubber elastic particles with respect to 100 parts by mass in total of the copolymer (1) and the polymer (2). Composition.
[4] An acrylic resin film comprising the acrylic resin composition according to any one of [1] to [3].
[5] A polarizing plate comprising the acrylic resin film according to [4].
[6] The method for producing an acrylic resin film according to [4], comprising extruding the acrylic resin composition according to any one of [1] to [3] from a die in a molten state into a film.
[7] The acrylic resin composition has 35 parts by mass or less of copolymer (1) and 65 of polymer (2) with respect to 100 parts by mass in total of copolymer (1) and polymer (2). The production method according to the above [6], which is an acrylic resin composition containing at least part by mass.

According to the present invention, it is possible to provide an acrylic resin composition having high impact resistance without lowering the elastic modulus.

Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

The acrylic resin composition of the present invention includes a copolymer (1) and a polymer (2).

[Copolymer (1)]
The copolymer (1) contained in the acrylic resin composition of the present invention comprises a structural unit represented by the formula (1a) (hereinafter sometimes referred to as “structural unit (1a)”) and the formula (1b). ) (Hereinafter sometimes referred to as “structural unit (1b)”).

The structural unit (1a) is represented by the formula (1a):

Is a structural unit represented by The structural unit (1a) is a structural unit derived from a relatively high molecular weight monomer having a polymerizable unsaturated group at the terminal (hereinafter, the monomer is referred to as “macromonomer”).

In formula (1a), R ¹¹ is a hydrogen atom or a methyl group, and preferably a methyl group from the viewpoint of heat resistance of the acrylic resin composition.
Since the terminal group R ¹² in the formula (1a) is determined by the polymerization initiator used when synthesizing the macromonomer corresponding to the structural unit (1a), it is not particularly limited. It may be a 2-cyano-2-propyl group or the like. That is, for example, when azobisisobutyronitrile is used as the polymerization initiator, R ¹² is a 2-cyano-2-propyl group.

In formula (1a), X represents formula (1a-1):

Or formula (1a-2):

It is a bivalent residue shown by.

In formula (1a-1), R ¹³ is a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of heat resistance of the acrylic resin composition.
In the formula (1a-1), R ¹⁴ represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a C 6 to 18 carbon atom. An aryl group. Examples of the linear alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. , N-nonyl group, n-decyl group, n-icosyl group and the like. Examples of the branched alkyl group having 3 to 20 carbon atoms include i-propyl group, i-butyl group, tert-butyl group, 2-ethylhexyl group and the like. Examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclohexyl group, and an adamantyl group. Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group and a naphthyl group. Since the corresponding macromonomer is easily available, the substituent R ¹⁴ is preferably a linear alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

N in the formula (1a-1) is a number of 70 or more as a number average value. n is usually 300 or less.
M in the formula (1a-2) is a number of 10 to 1000 as a number average value. m is preferably 30 to 100.
X is preferably a divalent residue represented by the formula (1a-1) because the transparency of the acrylic resin composition, particularly a film containing the acrylic resin composition, becomes good.

The structural unit (1b) is represented by the formula (1b):

Is a structural unit represented by

In the formula (1b), R ¹⁵ is a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of heat resistance of the acrylic resin composition.
In the formula (1b), R ¹⁶ represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms. It is. Examples of the linear alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. Group, n-nonyl group, n-decyl group, n-icosyl group and the like. Examples of the branched alkyl group having 3 to 20 carbon atoms include i-propyl group, i-butyl group, tert-butyl group, 2-ethylhexyl group and the like. Examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclohexyl group, and an adamantyl group. Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group and a naphthyl group. Since the corresponding monomer is easily available, the substituent R ¹⁶ is preferably a linear alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

The amount of the structural unit (1a) contained in the copolymer (1) is 5 to 70% by mass, preferably 5 to 50% by mass with respect to 100% by mass of all the structural units contained in the copolymer (1). %, More preferably 5 to 30% by mass, still more preferably 5 to 20% by mass, and particularly preferably 5 to 15% by mass. When the amount of the structural unit (1a) in the copolymer (1) is less than 5% by mass, the impact resistance is inferior, and when it exceeds 70% by mass, the elastic modulus is lowered. Is difficult to do. In the copolymer (1), as the structural unit (1a), one type of structural unit may be included, or a plurality of different types of structural units may be included.

The amount of the structural unit (1b) contained in the copolymer (1) is 30 to 95% by mass, preferably 50 to 95% by mass with respect to 100% by mass of all the structural units contained in the copolymer (1). %, More preferably 70 to 95% by mass, still more preferably 80 to 95% by mass, and particularly preferably 85 to 95% by mass. When the amount of the structural unit (1b) in the copolymer (1) exceeds 95% by mass, the impact resistance is inferior, and when it is less than 30% by mass, the elastic modulus is lowered. Is difficult to do. In the copolymer (1), as the structural unit (1b), one type of structural unit may be included, or a plurality of different types of structural units may be included.

The copolymer (1) includes the structural unit (1a) and the structural unit (1b) as essential structural units, and includes only the structural unit (1a) and the structural unit (1b) as structural units. Alternatively, it may include a structural unit other than the structural unit (1a) and the structural unit (1b) (hereinafter sometimes referred to as “structural unit (1c)”). Such a structural unit (1c) is particularly limited as long as it is derived from a macromonomer corresponding to the structural unit (1a) and a monomer copolymerizable with the monomer corresponding to the structural unit (1b). It is not something. Examples thereof include structural units derived from unsaturated acids such as acrylic acid and methacrylic acid, alkenyl cyanides such as acrylonitrile and methacrylonitrile, styrene monomers such as styrene and α-methylstyrene.

When the copolymer (1) contains the structural unit (1c), the amount is usually 10% by mass or less and 0% by mass with respect to 100% by mass of all the structural units contained in the copolymer (1). There may be.
In one embodiment of the present invention, the copolymer (1) does not contain the structural unit (1c).

The copolymer (1) is a copolymer of a macromonomer corresponding to the structural unit (1a) and a monomer corresponding to the structural unit (1b), and if necessary, a monomer corresponding to the structural unit (1c). Can be manufactured. The production method of the copolymer (1) is not particularly limited, and a copolymerization method known in the art can be used. For example, the macromonomer and the structural unit (1b) corresponding to the structural unit (1a) can be used. ) And a monomer corresponding to the structural unit (1c), if necessary, are usually mixed and polymerized using a polymerization initiator.

As the macromonomer corresponding to the structural unit (1a) contained in the copolymer (1), a commercially available one can be used, for example, trade name AA-6 (methacrylic acid) manufactured by Toagosei Co., Ltd. And compounds having a methacryloyloxy group added to the terminal of the methyl polymer: number average molecular weight 7300) and AS-6 (a compound having a methacryloyloxy group added to the terminal of the styrene polymer: number average molecular weight 7000).

Examples of the monomer corresponding to the structural unit (1b) contained in the copolymer (1) include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate.

The polymerization initiator is not particularly limited as long as it has the ability to initiate polymerization of the monomer corresponding to each structural unit, and can be appropriately selected from known polymerization initiators. In the present invention, examples of the polymerization initiator include thermal polymerization initiators that initiate polymerization by heating organic peroxides such as lauroyl peroxide and benzoyl peroxide, and azo compounds such as azobisisobutyronitrile. Can be mentioned. A polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type.

When a polymerization initiator is used in the production of the copolymer (1), the amount can be appropriately determined according to the type of monomer used, the content thereof, and the like. The amount is usually 0.01 to 5 parts by mass, preferably 1 part by mass or less, based on 100 parts by mass in total of all monomers used for constituting 1). As the amount of the polymerization initiator is larger, a copolymer (1) having a smaller number average molecular weight (Mn) is obtained.

In the production of the copolymer (1), a chain transfer agent may be used together with the polymerization initiator. As the chain transfer agent, for example, mercaptans such as n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan and 2-ethylhexyl thioglycolate are preferably used. These chain transfer agents may be used individually by 1 type, and may be used in combination of 2 or more type.

The amount of the chain transfer agent can be appropriately determined according to the type of monomer used and the content thereof. When a chain transfer agent is used, the amount used is usually 0.01 to 5 parts by mass with respect to 100 parts by mass in total of all monomers used to constitute the copolymer (1). The amount is preferably 0.01 to 1 part by mass.

As the polymerization method, for example, a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, and the like can be adopted. After the polymerization, the obtained copolymer (1) can be easily purified and taken out. Therefore, it is preferable to carry out by a suspension polymerization method in which the monomer is polymerized while being dispersed as droplets in water. Specifically, polymerization is initiated with a mixture of a macromonomer corresponding to the structural unit (1a) and a monomer corresponding to the structural unit (1b) and, if necessary, a monomer corresponding to the structural unit (1c). After adding an agent and, if necessary, a chain transfer agent, the mixture may be dispersed in water and heated with stirring. By stirring, the monomer is dispersed as droplets in water, and by heating, the polymerization initiator acts on the monomer in the droplet to initiate polymerization. The bead-like polymer (1) can be obtained by taking out the solid content from the reaction mixture after polymerization, washing with water and drying. The polymerization conditions (polymerization temperature, polymerization time, etc.) can be appropriately set according to the type and amount of the monomer used. The polymerization temperature is usually 0 to 120 ° C., for example 60 to 100 It is preferable that it is ° C. The polymerization time is usually 0.5 to 24 hours, for example, preferably 2 to 12 hours.

The weight average molecular weight (Mw) of the copolymer (1) is usually 50,000 to 2,000,000, preferably 100,000 to 1,500,000. When the weight average molecular weight of the copolymer (1) is within the above range, for example, it becomes easy to heat and melt the acrylic resin composition and process it into a film or the like.
The weight average molecular weight is determined by gel permeation chromatography using a multi-angle laser light scattering detector.

The number average molecular weight (Mn) of the copolymer (1) is usually 10,000 to 2,000,000, preferably 20,000 to 1,500,000. When the number average molecular weight of the copolymer (1) is within the above range, for example, it becomes easy to heat and melt the acrylic resin composition and process it into a film or the like.
The number average molecular weight is determined by gel permeation chromatography using a multi-angle laser light scattering detector.

The molecular weight distribution (Mw / Mn) of the copolymer (1) is usually from 1 to 5, preferably from 1 to 4. When the molecular weight distribution of the copolymer (1) is within the above range, for example, it becomes easy to heat and melt the acrylic resin composition and process it into a film or the like.

The copolymer (1) usually preferably has an average degree of branching of 0.3 to 0.95.
The average degree of branching was determined by gel permeation chromatography using a multi-angle laser light scattering detector as a detector, and the mean square radius r of the copolymer (1) and the polymer having the same molecular weight as the copolymer (1). An average square radius r _{0 of} methyl methacrylate is obtained and calculated as a ratio r / r ₀ thereof.

[Polymer (2)]
The polymer (2) contained in the acrylic resin composition of the present invention is a polymer containing a structural unit represented by the following formula (2a) (hereinafter sometimes referred to as “structural unit (2a)”).

The structural unit (2a) is represented by the formula (2a):

Is a structural unit represented by

In formula (2a), R ²¹ represents a hydrogen atom or a methyl group, and preferably a methyl group from the viewpoint of heat resistance of the acrylic resin composition.
In the formula (2a), R ²² is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms. is there.
Examples of the linear alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. , N-nonyl group, n-decyl group, n-icosyl group and the like. Examples of the branched alkyl group having 3 to 20 carbon atoms include i-propyl group, i-butyl group, tert-butyl group, 2-ethylhexyl group and the like. Examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclohexyl group, and an adamantyl group. Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group and a naphthyl group. In view of easy availability, the substituent R ²² is preferably a linear alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

The amount of the structural unit (2a) contained in the polymer (2) is preferably 10 to 100% by mass, preferably 15 to 100% by mass with respect to 100% by mass of all the structural units contained in the polymer (2). %, More preferably 20 to 100% by weight, further preferably 80 to 100% by weight, more preferably 90 to 100% by weight, and 95 to 100% by weight. % Is particularly preferred. When the amount of the structural unit (2a) in the polymer (2) is within the above range, the transparency of the acrylic resin composition, particularly a film containing the acrylic resin composition, becomes good. In the copolymer (2), as the structural unit (2a), one type of structural unit may be included, or a plurality of different types of structural units may be included.

The polymer (2) may contain the structural unit (1a). However, since the elastic modulus is lowered, when the polymer (2) contains the structural unit (1a), the amount is less than 5% by mass with respect to 100% by mass of all the structural units contained in the polymer (2). Yes, preferably less than 0.1% by weight. In a particularly preferred embodiment of the present invention, the polymer (2) does not contain the structural unit (1a) (that is, the amount of the structural unit (1a) may be 0% by mass).

The polymer (2) may contain only the structural unit (2a) as a structural unit. The polymer (2a) and the structural unit (2a) and 5% with respect to 100% by mass of all the structural units contained in the polymer (2). It may contain less than mass% of structural units (1a). Furthermore, the polymer (2) may include a structural unit other than the structural unit (2a) and the structural unit (1a) (hereinafter sometimes referred to as “structural unit (2b)”). Such a structural unit is particularly limited as long as it is derived from a monomer corresponding to the structural unit (2a) and a monomer copolymerizable with the monomer corresponding to the structural unit (1a). is not. Examples thereof include structural units derived from unsaturated acids such as acrylic acid and methacrylic acid, alkenyl cyanides such as acrylonitrile and methacrylonitrile, styrene monomers such as styrene and α-methylstyrene.

When the polymer (2) contains the structural unit (2b), the amount thereof is preferably 20% by mass or less, more preferably 10% by mass with respect to 100% by mass of all the structural units contained in the polymer (2). % Or less. In one embodiment of the present invention, the polymer (2) does not contain the structural unit (2b) (that is, the amount of the structural unit (2b) may be 0% by mass).

The polymer (2) can be produced by polymerizing the monomer corresponding to the structural unit (2a) and, if necessary, the monomer corresponding to the structural unit (1a) and / or (2b). it can. The production method of the polymer (2) is not particularly limited, and a copolymerization method known in the art can be used, for example, a monomer corresponding to the structural unit (2a), and if necessary The monomer corresponding to the structural unit (1a) and / or (2b) is mixed and usually polymerized using a polymerization initiator. As the polymerization method, for example, a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method and the like can be employed.

Examples of the monomer corresponding to the structural unit (2a) contained in the polymer (2) include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate.

The polymerization initiator is not particularly limited as long as it has the ability to initiate polymerization of the monomer corresponding to each structural unit, and can be appropriately selected from known polymerization initiators. For example, a polymerization initiator as exemplified in the polymerization of the copolymer (1) described above can be used.

The weight average molecular weight (Mw) of the polymer (2) is usually 50,000 to 300,000, more preferably 80,000 to 250,000. When the weight average molecular weight of the polymer (2) is within the above range, for example, it becomes easy to heat-melt the acrylic resin composition and process it into a film or the like.
The weight average molecular weight is determined by gel permeation chromatography using a multi-angle laser light scattering detector.

The number average molecular weight (Mn) of the polymer (2) is usually from 20,000 to 300,000, more preferably from 40,000 to 250,000. When the number average molecular weight of the polymer (2) is within the above range, for example, it becomes easy to heat and melt the acrylic resin composition and process it into a film or the like.
The number average molecular weight is determined by gel permeation chromatography using a multi-angle laser light scattering detector.

The molecular weight distribution (Mw / Mn) of the polymer (2) is usually 1 to 3. When the molecular weight distribution of the polymer (2) is within the above range, for example, it becomes easy to heat and melt the acrylic resin composition and process it into a film or the like.

A commercially available acrylic resin can also be used as the polymer (2). Examples of commercially available products include “SUMIPEX MH” and “SUMIPEX MHF” manufactured by Sumitomo Chemical Co., Ltd.

[Acrylic resin composition]
The acrylic resin composition of the present invention includes the copolymer (1) and the polymer (2).
The acrylic resin composition of the present invention comprises 1 to 90 parts by mass of the copolymer (1) with respect to 100 parts by mass in total of the copolymer (1) and the polymer (2), preferably 5 parts by mass or more. More preferably, it is 10 parts by mass or more, preferably 50 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less. In one embodiment of the present invention, the content of the copolymer (1) with respect to a total of 100 parts by mass of the copolymer (1) and the copolymer (2) may be, for example, 5 to 50 parts by mass. It may be ˜50 parts by mass, preferably 10 to 30 parts by mass. Further, the acrylic resin composition of the present invention contains 10 to 99 parts by mass, preferably 50 parts by mass of the polymer (2) with respect to 100 parts by mass of the total amount of the copolymer (1) and the polymer (2). Part or more, preferably 65 parts by weight or more, more preferably 70 parts by weight or more, preferably 95 parts by weight or less, more preferably 90 parts by weight or less. In one embodiment of the present invention, the content of the copolymer (2) with respect to 100 parts by mass in total of the copolymer (1) and the copolymer (2) may be, for example, 50 to 95 parts by mass, It may be ˜90 parts by mass, preferably 70 to 90 parts by mass. When the contents of the copolymer (1) and the polymer (2) are within the above range, high impact resistance can be ensured without reducing the elastic modulus of the acrylic resin composition.

In the acrylic resin composition of the present invention, X in the structural unit (1a) is a divalent residue represented by the formula (1a-1), and the structure with respect to all structural units contained in the copolymer (1) The amount of the unit (1a) is 5 to 15% by mass, and the copolymer (1) is used in an amount of 10 to 30 parts by mass and The acrylic resin composition containing 70 to 90 parts by mass of the combined body (2) can exhibit particularly high impact resistance.

The acrylic resin composition of the present invention may contain a polymer other than the copolymer (1) and the polymer (2). Examples of other polymers include unsaturated acids such as acrylic acid and methacrylic acid, alkenyl cyanides such as acrylonitrile and methacrylonitrile, styrene monomers such as styrene and α-methylstyrene, and the like. And the like. When the acrylic resin composition of the present invention contains a polymer other than the copolymer (1) and the polymer (2), the content thereof is that of the copolymer (1) and the polymer (2). It is usually 90 parts by mass or less, preferably 80 parts by mass or less with respect to 100 parts by mass in total.

The acrylic resin composition of the present invention may contain rubber elastic particles.
In the present invention, the rubber elastic particles may be particles composed only of a layer exhibiting rubber elasticity (hereinafter sometimes referred to as “rubber elastic layer”), and have other layers together with the rubber elastic layer. Particles having a multilayer structure may be used.

The rubber elastic layer includes a rubber elastic polymer. Examples of rubber elastic polymers include olefin elastic polymers, diene elastic polymers, styrene-diene elastic copolymers, acrylic elastic polymers, and the like. Among these, an acrylic elastic polymer is preferable from the viewpoint of light resistance and transparency of the acrylic resin composition of the present invention.

The acrylic elastic polymer may be a polymer mainly composed of alkyl acrylate, that is, a polymer containing 50 mass% or more of a structural unit derived from alkyl acrylate based on the total amount of monomers.
The acrylic elastic polymer may be a homopolymer of alkyl acrylate, the structural unit derived from alkyl acrylate is 50% by mass or more, and the structural unit derived from another polymerizable monomer is 50% by mass or less. It may be a copolymer containing

As the alkyl acrylate constituting the acrylic elastic polymer, those having 4 to 8 carbon atoms in the alkyl group are usually used. Examples of the other polymerizable monomer include, for example, alkyl methacrylate such as methyl methacrylate and ethyl methacrylate; styrene monomer such as styrene and alkyl styrene; unsaturated nitrile such as acrylonitrile and methacrylonitrile. Monofunctional monomers such as allyl (meth) acrylate, alkenyl esters of unsaturated carboxylic acids such as methallyl (meth) acrylate; dialkenyl esters of dibasic acids such as diallyl maleate; alkylene glycol di Polyfunctional monomers such as unsaturated carboxylic acid diesters of glycols such as (meth) acrylates.

The rubber particles containing an acrylic elastic polymer as the rubber elastic body are preferably multi-layered particles having an acrylic elastic polymer layer. Specifically, an acrylic elastic polymer and a two-layer structure having a hard polymer layer mainly composed of alkyl methacrylate on the outer or inner side of the acrylic elastic polymer layer, or the acrylic elastic polymer The thing of the 3 layer structure which has the hard polymer layer which has an alkyl methacrylate as a main body inside a polymer layer is mentioned.

Examples of the monomer composition in the polymer mainly composed of alkyl methacrylate constituting the hard polymer layer formed outside and / or inside the acrylic elastic polymer layer are methyl (meth) acrylate, (meth ) Ethyl acrylate, (meth) butyl acrylate, etc., which is a monomer composition of a polymer mainly composed of alkyl (meth) acrylate having about 1 to 4 carbon atoms, particularly a monomer composition mainly composed of methyl methacrylate Is preferably used. Such acrylic rubber particles having a multilayer structure can be produced, for example, by the method described in JP-B-55-27576.

The rubber particles preferably have a diameter (average particle diameter) to the outside of the rubber elastic layer (acrylic elastic polymer layer) contained therein of preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more. Yes, preferably 350 nm or less, more preferably 300 nm or less, and even more preferably 280 nm or less.

The diameter (average particle diameter) of the rubber particles to the outside of the rubber elastic layer (acrylic elastic polymer layer) is measured as follows. That is, when such rubber particles are mixed into an acrylic resin composition to form a film and the cross section is dyed with an aqueous solution of ruthenium oxide, only the rubber elastic body layer is colored and observed in a substantially circular shape, and the acrylic layer of the mother layer The system resin is not dyed. Therefore, from the cross section of the film dyed in this way, a thin piece is prepared using a microtome or the like, and this is observed with an electron microscope. And after extracting 100 dye | stained rubber particles at random and measuring each particle diameter (diameter to the outer side of a rubber elastic-body layer), the number average value is made into the said average particle diameter. In order to measure by such a method, the obtained average particle diameter is a number average particle diameter.

When the rubber particles are rubber particles whose outermost layer is a hard polymer mainly composed of methyl methacrylate and in which the rubber elastic layer (acrylic elastic polymer layer) is encapsulated, this rubber When the particles are mixed with the base acrylic resin, the outermost layer of the rubber particles is mixed with the base acrylic resin. Therefore, when the cross section is dyed with ruthenium oxide and observed with an electron microscope, the rubber particles are observed as particles in a state excluding the outermost layer. Specifically, when the inner layer is an acrylic elastic polymer and the outer layer is a rubber particle having a two-layer structure, which is a hard polymer mainly composed of methyl methacrylate, the acrylic elastic polymer portion of the inner layer Are dyed and observed as particles having a single layer structure. The innermost layer is a hard polymer mainly composed of methyl methacrylate, the intermediate layer is an acrylic elastic polymer, and the outermost layer is a rigid polymer mainly composed of methyl methacrylate. In the case of rubber particles, the central part of the innermost layer is not dyed, and only the acrylic elastic polymer part of the intermediate layer is dyed and observed as a two-layered particle.

When the acrylic resin composition of the present invention contains rubber elastic particles, the content thereof is usually 1 to 50 parts by mass with respect to 100 parts by mass in total of the copolymer (1) and the polymer (2). Yes, it is preferably 10-30 parts by mass, more preferably 10-20 parts by mass.
When the rubber elastic particles are included in the above range, higher impact resistance can be ensured as compared with the case where the rubber elastic particles are not blended. However, in the acrylic resin composition of the present invention, the high impact resistance of the acrylic resin composition can be ensured even if the rubber elastic body particles are not included. It may be 1 part by mass or less with respect to 100 parts by mass in total of (1) and the polymer (2), and may not contain rubber elastic particles at all (that is, the content of rubber elastic particles is 0 mass). %). Since the lower the elastic rubber particle content, the lower the modulus of elasticity can be suppressed. Therefore, the heat shrinkage of the film can be suppressed, and the heat resistance of the film is reduced. A decrease in the heat resistance of the plate can be suppressed.
In the present invention, when a particle having a multilayer structure having another layer in addition to a layer exhibiting rubber elasticity is used as the rubber particle, the mass of a portion composed of a rubber elastic body layer exhibiting rubber elasticity and an inner layer thereof Is the mass of the rubber particles. For example, when the rubber particles having the three-layer structure described above are used, the total mass of the acrylic elastic polymer portion in the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate in the innermost layer is determined as the rubber particles. Mass. When the acrylic rubber particles having the above three-layer structure are dissolved in acetone, the acrylic elastic polymer portion of the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate remain as insoluble matter. The total mass ratio of the intermediate layer and the innermost layer in the three-layered acrylic rubber particles can be easily obtained.

The acrylic resin composition of the present invention may contain additives such as an ultraviolet absorber, an antistatic agent, a light diffusing agent, a matting agent, a dye, a light stabilizer, an antioxidant, a release agent, and a flame retardant. Good.

The acrylic resin composition of the present invention can be produced by a conventionally known method. Specifically, for example, the polymer (1), the polymer (2), and optionally the rubber elastic particles and additives are uniaxially or It can be produced by a melt kneading method using a twin screw type extruder or the like. The form of the acrylic resin composition of the present invention is not particularly limited, but is preferably a pellet from the viewpoint of easy handling.

[Acrylic resin film and polarizing plate]
The acrylic resin film of the present invention can be produced by a known method such as a melt extrusion molding method or a press molding method. Specifically, for example, in the case of melt extrusion molding, various materials constituting the acrylic resin composition of the present invention are melt-kneaded with an extruder to obtain a molten acrylic resin composition of the present invention, or After the acrylic resin composition of the invention is melt-kneaded with an extruder to obtain a molten state, it can be produced by extruding the molten acrylic resin composition of the present invention from a die into a film. The molding conditions (extrusion conditions) are not particularly limited, and may be appropriately adjusted according to the composition of the acrylic resin composition used, the molecular weight / molecular weight distribution of the acrylic resin composition, and the like. For example, the extrusion temperature is usually about 230 to 300 ° C. Further, in the case of a press molding method, the acrylic resin composition of the present invention is placed between a pair of press molds and heated in a state of being sandwiched between both molds. It can be produced by heating the acrylic resin composition and shaping it into a sheet as a molten state.

When the acrylic resin film of the present invention is produced by the melt extrusion molding method, the resulting acrylic resin film has a Charpy impact in the extrusion direction (MD direction) and in the width direction (TD direction) perpendicular to this in the plane. Although the ratio of increasing the strength may be different, the content of the copolymer (1) with respect to 100 parts by mass in total of the copolymer (1) and the polymer (2) is 35 parts by mass or less. When the content of 2) is 65 parts by mass or more, the Charpy impact strength in both the extrusion direction (MD direction) and the width direction (TD direction) is improved, which is preferable.

Since the acrylic resin film of the present invention exhibits high impact resistance while maintaining the required elastic modulus, it can be used, for example, as a protective film constituting a polarizing plate. The thickness of the acrylic resin film is not particularly limited, but is preferably 10 to 300 μm when used for the above applications.

The polarizing plate of the present invention includes the acrylic resin film of the present invention. The polarizing plate of the present invention preferably includes the acrylic resin film of the present invention as a protective film of the polarizing plate by laminating the acrylic resin film of the present invention on one or both surfaces of the polarizing film. In this case, the acrylic resin film may be used unstretched or may be stretched.

As the polarizing film included in the polarizing plate of the present invention, a polarizing film used in a conventionally known polarizing plate can be used. The polarizing film in the polarizing plate of the present invention is a film in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin film, and absorbs polarized light having a vibration plane parallel to the absorption axis. In addition, it is an optical film having a property of transmitting polarized light having a vibration plane orthogonal to the absorption axis. The acrylic resin film of the present invention is laminated with a polarizing film, usually via an adhesive. For example, a polarizing film and an acrylic resin film are bonded via an aqueous polyvinyl alcohol resin solution and then dried, or a polarizing film and an acrylic resin film are bonded via an ultraviolet curable adhesive. Then, the polarizing plate of this invention can be manufactured by irradiating and hardening | curing an ultraviolet-ray.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, “%” and “parts” represent “% by mass” and “parts by mass”, respectively, unless otherwise specified.

1. Preparation of Copolymer (1) <Synthesis Example 1>
According to the composition shown in Table 1, 87.3% by mass of methyl methacrylate (MMA), 10.7% by mass of macromonomer (AA-6: a structure in which a methacryloyloxy group is added to the end of the methyl methacrylate polymer, Toagosei Co., Ltd.) and 2.0% by mass of methyl acrylate (MA) were mixed to obtain a monomer component. To this monomer component, 0.1 part by weight of lauroyl peroxide (polymerization initiator) and 0.2 part by weight of n-octylcaptan (chain transfer agent) are added based on 100 parts by weight of the monomer component. These were added and dissolved to obtain a monomer mixture. Separately, with respect to 100 parts by mass of ion-exchanged water, 0.05 parts by mass of sodium polyacrylate, 0.24 parts by mass of anhydrous sodium phosphate as a suspension stabilizer, 7 parts of dibasic sodium phosphate 7 0.28 parts by mass of hydrate was added and dissolved to obtain a suspension polymerization aqueous phase. Next, 200 parts by mass of the suspension polymerization aqueous phase was added to 100 parts by mass of the monomer component to the monomer mixture, and suspension polymerization was performed. The obtained slurry-like reaction liquid was dehydrated and washed with a dehydrator and then dried to obtain a bead-shaped copolymer (1-A). With respect to the obtained copolymer (1-A), the molecular weight and the average branching degree were measured according to the following method. The results are shown in Table 1.

<Weight average molecular weight (Mw) and number average molecular weight (Mn)>
The obtained copolymer (1-A) was dissolved in a tetrahydrofuran (THF) solvent to prepare a measurement sample. Using a gel permeation chromatography (GPC) apparatus, the elution time and strength were measured at an injection volume of the measurement sample of 200 μL, a flow rate of 1.0 mL / min, and a measurement temperature of 40 ° C. As the GPC apparatus, HLC8220-GPC manufactured by Tosoh Corporation (two “TSKgel GMHHR-H” manufactured by Tosoh Corporation as a column and equipped with an RI detector) was used. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the measurement sample were determined by a multi-angle laser light scattering detector (DAWN HELEOS manufactured by Wyatt Technology). Furthermore, molecular weight distribution (Mw / Mn) was calculated from these values.

<Average branching degree>
By gel permeation chromatography using the multi-angle laser light scattering detector, the mean square radius r of the copolymer (1-A) and the mean square radius r ₀ of the linear polymethyl methacrylate having the same molecular weight are obtained. the demand was calculated by _r / r _0. The smaller this value, the more branched structures are introduced per polymer chain.

<Weight average molecular weight (Mw) and number average molecular weight (Mn) of macromonomer>
Macromonomer AA-6 was dissolved in a tetrahydrofuran (THF) solvent to prepare a measurement sample. Using a gel permeation chromatography (GPC) apparatus, the elution time and strength were measured with an injection volume of the measurement sample of 20 μL, a flow rate of 1.0 mL / min, and a measurement temperature of 40 ° C. As the GPC apparatus, HLC8320-GPC manufactured by Tosoh Corporation (including two “TSKgel SuperMultipore HZ_M” and one “TSKgel SuperHZ2500” manufactured by Tosoh Corporation) were used. On the other hand, a calibration curve was prepared from a standard sample using this apparatus. Based on the elution time and strength of the macromonomer determined above, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the macromonomer were determined based on the calibration curve. The standard sample used was polymethyl methacrylate (PMMA). Furthermore, molecular weight distribution (Mw / Mn) was calculated from these values. The weight average molecular weight (Mw) of the macromonomer AA-6 is 13600, the number average molecular weight (Mn) is 7300, the molecular weight distribution (Mw / Mn) is 1.9, and is obtained from the number average molecular weight (Mn). The n was 72.

<Synthesis Examples 2 to 10>
According to the composition shown in Table 1, copolymers (1-B) to (1-J) were prepared in the same procedure as in Synthesis Example 1. In Synthesis Examples 3 to 6, 150 parts by mass of the suspension polymerization aqueous phase was added to 100 parts by mass of the monomer component. In Synthesis Examples 3 and 4, instead of the macromonomer (AA-6), a macromonomer having a structure in which a methacryloyloxy group is added to the end of the methyl methacrylate polymer (Mw = 20500, Mn = 10000, Mw / Mn = 2.0, n = 100 determined from Mn) in Synthesis Examples 5 and 6, a macromonomer having a structure in which a methacryloyloxy group was added to the end of the methyl methacrylate polymer (Mw = 37300, Mn = 19100, Mw). /Mn=1.9 and n = 190 determined from Mn were used. In Synthesis Example 7 and Synthesis Example 8, instead of the macromonomer (AA-6), a macromonomer (AS-6: a compound in which a methacryloyloxy group is added to the end of a styrene polymer, manufactured by Toagosei Co., Ltd.) Was used. The weight average molecular weight (Mw) of the macromonomer (AS-6) is 13700, the number average molecular weight (Mn) is 7000, the molecular weight distribution (Mw / Mn) is 2.0, and m obtained from Mn is 65. The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the macromonomer used in Synthesis Example 3 to Synthesis Example 8 were measured for the macromonomer (AA-6) in Synthesis Example 1. Measured and calculated in the same manner as calculated. Table 1 shows the molecular weight and average branching degree of the obtained copolymer.

<Synthesis Example 11>
According to the composition shown in Table 1, a bead-like acrylic resin not containing a macromonomer-derived structural unit was obtained in the same procedure as in Synthesis Example 1. Table 1 shows the molecular weight of the obtained acrylic resin.

2. Preparation of Acrylic Resin Composition and Acrylic Resin Film In the following examples and comparative examples, copolymers (1-A) to (1-J) prepared in Synthesis Examples 1 to 10 were used as copolymers (1). ) Or the acrylic resin prepared in Synthesis Example 11, and the polymer (2) is a methyl methacrylate resin containing 90% by mass or more of a structural unit derived from methyl methacrylate [hereinafter referred to as “acrylic resin (2)”. The amount of the structural unit (1a) in the acrylic resin (2) is 0% by mass]. The acrylic resin (2) had a weight average molecular weight (Mw) of 102600, a number average molecular weight (Mn) of 54700, and a molecular weight distribution (Mw / Mn) of 1.9. The following rubber elastic particles were used.

<Rubber elastic particles>
Hard rubber obtained by polymerization of a monomer mixture consisting of 93.8% by weight of methyl methacrylate, 6.0% by weight of methyl acrylate, and 0.2% by weight of allyl methacrylate as the rubber elastic particles. And an intermediate layer is an elastic polymer obtained by polymerization of a monomer mixture comprising 81% by mass of butyl acrylate, 17% by mass of styrene and 2% by mass of allyl methacrylate, and the outermost layer is methyl methacrylate. A hard polymer obtained by polymerization of a monomer mixture consisting of 94% by mass and 6% by mass of methyl acrylate, wherein the mass ratio of the innermost layer / intermediate layer / outermost layer is 35/45/20, Rubber elastic particles having a spherical three-layer structure obtained by an emulsion polymerization method in which the average particle diameter of the elastic polymer layer of the intermediate layer was 0.22 μm were used.

The average particle diameter of the rubber elastic particles is obtained by mixing the rubber elastic particles with the acrylic resin composition into a film, staining the elastic polymer (intermediate layer) with ruthenium oxide in the cross section, and observing with an electron microscope. It was determined from the diameter of the stained part.

<Example 1: Preparation of acrylic resin composition and production of press film>
5 parts by mass of copolymer (1-A) and 95 parts by mass of acrylic resin (2) were mixed and melt-kneaded using an extruder to form pellets. Then, the said pellet was shape | molded with the compression molding machine, and produced the press film of 80 mm x 80 mm square and thickness 300 micrometers. For the press treatment, a 210 ° C. press (manufactured by Shin-Fuji Metal Industry Co., Ltd., NSF-100 type single acting compression molding machine) was used. First, it was heated for 5 minutes as preheating, and then held for 3 minutes under a pressure of about 2 MPa. Thereafter, it was held for 1 minute under a pressure of about 13 MPa. Further, the molded film was taken out from the press while being sandwiched between iron plates, and cooled on a cooling plate for 5 minutes to obtain a press film.

<Examples 2 to 14: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 2, the copolymers (1-A) to (1-H) and the acrylic resin (2) were mixed, and a pellet-shaped acrylic resin composition was prepared in the same manner as in Example 1. Then, a press film of 80 mm × 80 mm square and a thickness of 300 μm was produced.

<Examples 15 and 16: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 3, 15 parts by mass of copolymer (1-I) or copolymer (1-J), 85 parts by mass of acrylic resin (2), and copolymer (1-I) or copolymer 11.7 parts by mass of rubber elastic material particles were mixed with 100 parts by mass of the combined (1-J) and acrylic resin (2), and melt-kneaded using an extruder to form pellets. Then, it shape | molded with the compression molding machine like Example 1, and produced the press film of 80 mm x 80 mm square and thickness 300 micrometers.

<Comparative Example 1: Production of press film>
A 80 mm × 80 mm square, 300 μm-thick press film was produced from the pellet-shaped acrylic resin (2) in the same manner as in Example 1.

<Comparative Examples 2 to 4: Preparation of acrylic resin composition and production of press film>
The bead-like copolymer (1-A), copolymer (1-B) or copolymer (1-G) is pelletized with an extruder and then molded with a compression molding machine in the same manner as in Example 1. Then, a press film of 80 mm × 80 mm square and a thickness of 300 μm was produced.

<Comparative Examples 5 and 6: Preparation of acrylic resin composition and production of press film>
The acrylic resin synthesized in Synthesis Example 11 and the acrylic resin (2) were mixed according to the composition shown in Table 2, and melt-kneaded using an extruder to be pelletized. Then, it shape | molded with the compression molding machine like Example 1, and produced the press film of 80 mm x 80 mm square and thickness 300 micrometers.

<Comparative Example 7: Production of press film>
The bead-shaped acrylic resin synthesized in Synthesis Example 11 was pelletized with an extruder. Then, it shape | molded with the compression molding machine like Example 1, and produced the press film of 80 mm x 80 mm square and thickness 300 micrometers.

<Comparative Example 8: Preparation of acrylic resin composition and production of press film>
11.7 parts by mass of rubber elastic particles were mixed with 100 parts by mass of the acrylic resin (2), and the mixture was melt-kneaded by an extruder and pelletized. Then, it shape | molded with the compression molding machine like Example 1, and produced the press film of 80 mm x 80 mm square and thickness 300 micrometers.

The Charpy impact strength and 80 ° C. elastic modulus of the press films prepared in Examples 1 to 16 and Comparative Examples 1 to 8 were measured according to the following methods.

<Charpy impact test>
In accordance with the method defined in JIS K7111-1, the obtained press film sample was cut into a rectangle with a length of 80 mm and a width of 10 mm, and Charpy impact strength was measured with both short sides (10 mm) fixed, and the press The impact resistance of the film was evaluated. The results are shown in Tables 2 and 3. In Table 2, the impact strength values are relative values (%) when the Charpy impact strength value of the press film of Comparative Example 1 (acrylic resin composition composed only of acrylic resin (2)) is 100%. The value of the impact strength in Table 3 is 100% of the Charpy impact strength value of the press film of Comparative Example 8 (acrylic resin composition comprising only acrylic resin (2) and rubber elastic particles). Relative value (%) in the case of the above, each indicated as “relative Charpy impact strength (%)”. If the value of the relative Charpy impact strength (%) was 100 or more, it was judged that the impact resistance was high.

<80 ° C elastic modulus measurement>
Each press film of the example and the comparative example was cut into a rectangle of 80 mm in the vertical direction and 25 mm in the horizontal direction, and a tensile test was performed at 80 ° C. with a distance between chucks of 50 mm and a tensile speed of 1 mm / min in the vertical direction. The tensile elastic modulus at 80 ° C. was calculated from the slope of the stress-strain curve in the region where the tensile strength was from 1 MPa to 3 MPa. The results are shown in Tables 2 and 3. In addition, the value in 80 degreeC elasticity modulus in Table 2 is relative when the value of 80 degreeC elasticity modulus of the press film of the comparative example 1 (acrylic resin composition comprised only with acrylic resin (2)) is set to 100%. The value at 80 ° C. elastic modulus in Table 3 is the 80 ° C. elastic modulus of the press film of Comparative Example 8 (acrylic resin composition composed only of acrylic resin (2) and rubber elastic particles). Are relative values (%) when the value of 100 is 100 (%), and each is described as “relative 80 ° C. elastic modulus (%)”. If the value of the relative 80 ° C. elastic modulus (%) was 96 or more, it was judged that there was no decrease in elastic modulus / excellent elastic modulus.

As shown in Table 2, 5 to 70% by mass of the structural unit represented by the formula (1a) and 30 to 95% by mass of the structure represented by the formula (1b) with respect to all the structural units contained in the copolymer. The copolymer (1) containing the unit and the polymer (2) containing the structural unit represented by the formula (2a), and the total amount of the copolymer (1) and the polymer (2) is 100 parts by mass. On the other hand, a film composed of an acrylic resin composition having 1 to 90 parts by mass of the copolymer (1) and 10 to 99 parts by mass of the polymer (2) does not decrease the elastic modulus and has impact resistance. (Examples 1 to 14) were improved. On the other hand, when the contents of the copolymer (1) and the polymer (2) are not within the above ranges, sufficient impact resistance cannot be obtained, or the 80 ° C. elastic modulus is remarkably reduced (Comparative Example 2). ~ 7).
Moreover, it was confirmed that the impact resistance is further increased by adding a rubber elastic body (Examples 15 and 16).

<Synthesis Examples 12 to 14>
According to the composition shown in Table 4, bead-like copolymers (1-K) to (1-M) were prepared in the same procedure as in Synthesis Example 1. In Synthesis Example 12, instead of the macromonomer (AA-6), a macromonomer having a structure in which a methacryloyloxy group is added to the terminal of the methyl methacrylate polymer (Mw = 22300, Mn = 11000, Mw / Mn = 2. 0, n = 110 determined from Mn, in Synthesis Example 13, a macromonomer having a structure in which a methacryloyloxy group was added to the end of a methyl methacrylate polymer (Mw = 41500, Mn = 20100, Mw / Mn = 2) .1, n = 200 determined from Mn), in Synthesis Example 14, a macromonomer (Mw = 55900, Mn = 24300, Mw / Mn =) having a structure in which a methacryloyloxy group was added to the end of the methyl methacrylate polymer. 2.3, n = 241) determined from Mn was used. The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the macromonomer used in Synthesis Example 12 to Synthesis Example 14 were measured for the macromonomer (AA-6) in Synthesis Example 1. Measured and calculated in the same manner as calculated. Table 4 shows the molecular weight and average branching degree of the obtained copolymer.

<Examples 17 to 31: Preparation of acrylic resin composition and production of extruded film>
According to the composition shown in Table 5, bead-shaped copolymer (1-K) or copolymer (1-L) or copolymer (1-M), acrylic resin (2), and copolymer (1 -K), or copolymer (1-L) or copolymer (1-M) and acrylic resin (2) in total, 100 parts by mass of rubber elastic body particles 11.7 parts by mass, Using an axial extruder (VS20-26V type extruder manufactured by Tanabe Plastic Machinery Co., Ltd.), the film was formed by open molding to produce an extruded film having a thickness of 40 μm. The die temperature during extrusion was 250 ° C.

<Comparative Example 9: Preparation of acrylic resin composition and production of extruded film>
11.7 parts by mass of rubber elastic particles are mixed with 100 parts by mass of acrylic resin (2), and open molding is performed using a 20 mmφ single screw extruder (VS20-26V type extruder manufactured by Tanabe Plastic Machinery Co., Ltd.). To produce an extruded film having a thickness of 40 μm. The die temperature during extrusion was 250 ° C.
The compositions of the acrylic resin (2) and the rubber elastic particles used in Examples 17 to 31 and Comparative Example 9 are the same as those used in Example 15, respectively.

The Charpy impact strength and 80 ° C. elastic modulus of the extruded films prepared in Examples 17 to 31 and Comparative Example 9 were measured according to the following methods.

<MD direction Charpy impact test>
According to the method specified in JIS K7111-1, the extruded film is cut into a rectangle with a longitudinal direction (MD direction) of 100 mm and a lateral direction (TD direction) of 10 mm, and both short sides (sides of 10 mm) are fixed, and MD direction Charpy is fixed. The impact strength was measured and the impact resistance of the extruded film was evaluated. The results are shown in Table 5. The value in impact strength in Table 5 is 100% of the value of Charpy impact strength in the MD direction of the extruded film of Comparative Example 9 (acrylic resin composition composed only of acrylic resin (2) and rubber elastic particles). The relative value (%) in the case of “MD direction relative Charpy impact strength (%)”. If the value of MD direction relative Charpy impact strength (%) was 100 or more, it was judged that the impact resistance was high.

<TD direction Charpy impact test>
In accordance with the method specified in JIS K7111-1, the extruded film is cut into a rectangle of 10 mm in the machine direction (MD direction) and 100 mm in the transverse direction (TD direction), and both short sides (sides of 10 mm) are fixed. Was measured and the impact resistance of the extruded film was evaluated. The results are shown in Table 5. The value in impact strength in Table 5 is 100% of the value of Charpy impact strength in the TD direction of the extruded film of Comparative Example 9 (acrylic resin composition composed only of acrylic resin (2) and rubber elastic particles). The relative value (%) in the case of “TD direction relative Charpy impact strength (%)”. If the value of the TD direction relative Charpy impact strength (%) was 100 or more, it was judged that the impact resistance was high.

<Measurement of elastic modulus at 80 ° C. in MD direction>
The extruded film was cut into a rectangle having a longitudinal direction (MD direction) of 100 mm and a transverse direction (TD direction) of 25 mm, and a tensile test was conducted at 80 ° C. with a distance between chucks of 50 mm and a longitudinal speed of 1 mm / min. The tensile elastic modulus at 80 ° C. was calculated from the slope of the stress-strain curve in the region where the tensile strength was 3 MPa to 6 MPa. The results are shown in Table 5. In addition, the value in 80 degreeC elasticity modulus in Table 5 is the value of 80 degreeC elasticity modulus of MD direction of the extrusion film of the comparative example 9 (acrylic resin composition comprised only with acrylic resin (2) and rubber elastic-body particle | grains). It is a relative value (%) when it is 100%, and is described as “MD direction relative 80 ° C. elastic modulus”. If the value of the relative 80 ° C. elastic modulus (%) was 96 or more, it was judged that there was no decrease in elastic modulus / excellent elastic modulus.

<Measurement of elastic modulus at 80 ° C in TD direction>
The extruded film was cut into a rectangle with a longitudinal direction (MD direction) of 25 mm and a transverse direction (TD direction) of 100 mm, and a tensile test was conducted at 80 ° C. with a distance between chucks of 50 mm at a tensile speed of 1 mm / min. The tensile elastic modulus at 80 ° C. was calculated from the slope of the stress-strain curve in the region where the tensile strength was 3 MPa to 6 MPa. The results are shown in Table 5. In addition, the value in 80 degreeC elastic modulus in Table 5 is the value of 80 degreeC elastic modulus in the TD direction of the extruded film of Comparative Example 9 (acrylic resin composition composed only of acrylic resin (2) and rubber elastic particles). It is a relative value (%) when it is 100%, and is described as “TD direction relative 80 ° C. elastic modulus”. If the value of the relative 80 ° C. elastic modulus (%) was 96 or more, it was judged that there was no decrease in elastic modulus / excellent elastic modulus.

<Synthesis Example 15>
According to the composition shown in Table 6, a bead-shaped copolymer (1-N) was prepared in the same procedure as in Synthesis Example 1. The obtained copolymer (1-N) was measured for molecular weight and average degree of branching according to the same method as in Synthesis Example 1. The results are shown in Table 6.

<Example 32: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 7, the copolymer (1-N) and Densica Co., Ltd. Resphi R200 were mixed to prepare a pellet-like acrylic resin composition in the same manner as in Example 1, and then 80 mm × A press film of 80 mm square and a thickness of 300 μm was produced. The weight average molecular weight (Mw) of R200 is 185000, the number average molecular weight (Mn) is 79000, and the molecular weight distribution (Mw / Mn) is 2.4 (PMMA conversion).

<Example 33: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 7, the copolymer (1-I) and HT121 manufactured by Arkema Co., Ltd. were mixed to prepare a pellet-like acrylic resin composition in the same manner as in Example 1, and then 80 mm × A press film of 80 mm square and a thickness of 300 μm was produced. In addition, the weight average molecular weight (Mw) of HT121 is 78000, the number average molecular weight (Mn) is 41000, and molecular weight distribution (Mw / Mn) is 1.9 (PMMA conversion).

<Comparative Example 10: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 7, acrylic resin (2) and Denka Co., Ltd. Regisfi R200 were mixed, and in the same manner as in Example 1, a pellet-shaped acrylic resin composition was prepared, and then 80 mm × 80 mm square, A press film having a thickness of 300 μm was produced.

<Comparative Example 11: Preparation of acrylic resin composition and production of press film>
According to the composition shown in Table 7, the acrylic resin (2) and HT121 manufactured by Arkema Co., Ltd. were mixed to prepare a pellet-shaped acrylic resin composition in the same manner as in Example 1, and then 80 mm × 80 mm square, A press film having a thickness of 300 μm was produced.

The Charpy impact strength and 80 ° C. elastic modulus of the press films prepared in Examples 32 and 33 and Comparative Examples 10 and 11 were measured according to the following methods.

<Charpy impact test>
In accordance with the method defined in JIS K7111-1, the obtained press film sample was cut into a rectangle with a length of 80 mm and a width of 10 mm, and Charpy impact strength was measured with both short sides (10 mm) fixed, and the press The impact resistance of the film was evaluated. The results are shown in Table 7. The value of impact strength in Example 32 in Table 7 is 100% of the Charpy impact strength value of the press film of Comparative Example 10 (acrylic resin composition composed of acrylic resin (2) and R200). Relative value (%) in Table 7, and the value in impact strength in Example 33 in Table 7 is the Charpy impact of the press film of Comparative Example 11 (acrylic resin composition composed of acrylic resin (2) and HT121). It is a relative value (%) when the strength value is 100%, and is described as “relative Charpy impact strength (%)”. If the value of the relative Charpy impact strength (%) was 100 or more, it was judged that the impact resistance was high.

<80 ° C elastic modulus measurement>
Each press film of the example and the comparative example was cut into a rectangle of 80 mm in the vertical direction and 25 mm in the horizontal direction, and a tensile test was performed at 80 ° C. with a distance between chucks of 50 mm and a tensile speed of 1 mm / min in the vertical direction. The tensile elastic modulus at 80 ° C. was calculated from the slope of the stress-strain curve in the region where the tensile strength was from 1 MPa to 3 MPa. The results are shown in Table 7. In addition, the value in the 80 degreeC elasticity modulus in Example 32 in Table 7 is the value of the 80 degreeC elasticity modulus of the press film of the comparative example 10 (acrylic resin composition comprised by acrylic resin (2) and R200) as 100. %, The value at 80 ° C. elastic modulus in Example 33 in Table 7 is that of Comparative Example 11 (acrylic resin composition composed of acrylic resin (2) and HT121). Relative values (%) when the 80 ° C. elastic modulus value of the press film is taken as 100 (%), and each is described as “relative 80 ° C. elastic modulus (%)”. If the value of the relative 80 ° C. elastic modulus (%) was 96 or more, it was judged that there was no decrease in elastic modulus / excellent elastic modulus.

Claims

An acrylic resin composition comprising a copolymer (1) and a polymer (2),
The copolymer (1) is a structural unit represented by the following formula (1a):

[Wherein R 11 represents a hydrogen atom or a methyl group, R 12 represents a terminal group, and X represents a formula (1a-1):

(Wherein R 13 is a hydrogen atom or a methyl group, and R 14 is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or An aryl group having 6 to 18 carbon atoms, and n is a number average value of 70 or more)
Or a divalent residue represented by the formula (1a-2):

(Where m is a number from 10 to 1000 as a number average value)
It is a divalent residue represented by
And a structural unit represented by the following formula (1b):

[Wherein, R 15 represents a hydrogen atom or a methyl group, and R 16 represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or It is an aryl group having 6 to 18 carbon atoms.]
Including
5 to 70% by mass of the structural unit represented by the formula (1a) and 30 to 95% by mass of the structural unit represented by the formula (1b) with respect to all the structural units contained in the copolymer (1). A copolymer,
The polymer (2) is a structural unit represented by the following formula (2a):

[Wherein R 21 represents a hydrogen atom or a methyl group, and R 22 represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or It is an aryl group having 6 to 18 carbon atoms.]
(However, the structural unit represented by the formula (1a) is less than 5% by mass with respect to all the structural units contained in the polymer (2)),
Acrylic resin composition comprising 1 to 90 parts by mass of copolymer (1) and 10 to 99 parts by mass of polymer (2) with respect to 100 parts by mass in total of copolymer (1) and polymer (2) object.
X in the formula (1a) is a divalent residue represented by the formula (1a-1), and the structural unit represented by the formula (1a) with respect to all the structural units contained in the copolymer (1). The amount is 5 to 15% by mass, and 10 to 30 parts by mass of the copolymer (1) and the polymer (2) with respect to 100 parts by mass in total of the copolymer (1) and the polymer (2). The acrylic resin composition according to claim 1, comprising 70 to 90 parts by mass.
The acrylic resin composition according to claim 1 or 2, comprising 1 to 50 parts by mass of rubber elastic body particles with respect to a total of 100 parts by mass of the copolymer (1) and the polymer (2).
An acrylic resin film comprising the acrylic resin composition according to any one of claims 1 to 3.
A polarizing plate comprising the acrylic resin film according to claim 4.
The method for producing an acrylic resin film according to claim 4, comprising extruding the acrylic resin composition according to any one of claims 1 to 3 from a die in a molten state.
The acrylic resin composition comprises 35 parts by mass or less of the copolymer (1) and 65 parts by mass or more of the polymer (2) with respect to a total of 100 parts by mass of the copolymer (1) and the polymer (2). The manufacturing method of Claim 6 which is an acrylic resin composition containing.