JP6725113B2 - Acrylic film - Google Patents

Description

TECHNICAL FIELD The present invention relates to an acrylic film composed of a methacrylic resin composition, and more particularly to an acrylic film having high transparency, bending whitening resistance, high rigidity, high heat resistance and excellent surface smoothness.

Methacrylic resin has high transparency and is useful as a material for a molded body used for an optical member, a lighting member, a sign member, a decorative member, and the like. However, since the glass transition temperature is as low as about 110° C., the molded product made of the methacrylic resin has a problem that it is easily deformed by heat.

As a methacrylic resin having a high glass transition temperature, a methacrylic resin having a high syndiotacticity is known. As a method for producing a methacrylic resin having high syndiotacticity, a method by anionic polymerization can be mentioned (see Patent Documents 1 and 2). Further, there is known a resin composition in which a methacrylic resin having high syndiotacticity is mixed with a reinforcing agent having a multilayer structure to improve impact resistance and bending strength (Patent Document 3). An acrylic film in which an acrylic block copolymer is mixed with a methacrylic resin is also known (Patent Document 4).

However, the technique of Patent Document 3 does not sufficiently disclose the suitable reinforcing agent. Further, in the technique of Patent Document 4, the heat resistance is not sufficient, and the applications of the obtained acrylic film are limited.

Further, in recent years, along with the progress of thinning of liquid crystal display devices and the like, thinning of films used for polarizer protective films and the like has also progressed. Under such circumstances, the conventionally used film made of triacetyl cellulose has a high moisture permeability, and thus there is a problem that the quality of the polarizer is deteriorated as the film is made thinner. Therefore, the development of a polarizer protective film that replaces triacetyl cellulose has been an issue in reducing the thickness of liquid crystal display devices.

Therefore, acrylic films have been studied as a candidate for a new polarizer protective film, but acrylic films are fragile, and there is a problem that the rigidity of the film itself is reduced due to thinning and the surface hardness is reduced. It was

JP-A-3-263412 JP, 2002-327012, A JP-A-6-287398 International Publication 2014/073216

An object of the present invention is to provide an acrylic film having high transparency, high glass transition temperature, chemical resistance, whitening resistance, and high surface hardness.

As a result of intensive studies to achieve the above object, the present invention has been completed. The mode will be described below.

(1): a methacrylic resin [1] having a syndiotacticity (rr) of 65% or more in triplets, and an elastomer component [2] containing 30% by mass or more of a structural unit derived from an acrylate ester. An acrylic film comprising a methacrylic resin composition containing a methacrylic resin [1]/elastomer component [2] in a mass ratio of 60/40 to 99/1.
An acrylic film, wherein a major axis of a dispersed phase derived from the elastomer component [2] is 10 to 300 nm when a thin piece of the acrylic film is dyed with phosphotungstic acid.

(2): Acrylic film according to (1), wherein the methacrylic resin [1] has a molecular weight distribution of 1.5 or less. (3): The methacrylic resin [1]/elastomer component [2] The acrylic film according to (1) or (2), wherein the mass ratio is 80/20 to 99/1. (4): A methacrylic acid ester as a main component as the elastomer component [2]. Any one of (1) to (3) containing a block copolymer comprising a combination of a polymer (b1) having a structural unit and a polymer (b2) having a structural unit composed of an acrylic ester. The acrylic film described.
(5): The acrylic film as described in any one of (1) to (4), which contains a core-shell type graft copolymer as the elastomer component [2].

(6): The acrylic film as described in any one of (1) to (5), wherein the methacrylic resin composition further contains an ultraviolet absorber.
(7): The methacrylic resin composition further contains 1 to 10 parts by mass of a polycarbonate resin based on 100 parts by mass of the total amount of the methacrylic resin [1] and the elastomer component [2], (1) to The acrylic film as described in any one of (6).

(8): A laminated film using the acrylic film according to any one of (1) to (7).
(9): A polarizer protective film made of the acrylic film according to any one of (1) to (7).

(10): A methacrylic resin [1] having a syndiotacticity (rr) of 65% or more in triplets, and an elastomer component [2] containing 30% by mass or more of a structural unit derived from an acrylate ester. Are melt-kneaded at a mass ratio of methacrylic resin [1]/elastomer component [2] of 60/40 to 99/1 to obtain a methacrylic resin composition, and the methacrylic resin composition is molded to obtain an acrylic film. The method for producing an acrylic film, wherein the major axis of the disperse phase derived from the elastomer component [2] when the thin piece of the acrylic film is dyed with phosphotungstic acid is 10 to 300 nm. Method.
(11) The method for producing an acrylic film according to (10), wherein the acrylic film is further stretched.

(12): The method for producing an acrylic film according to (10) or (11), which further comprises melt-kneading a polycarbonate resin to obtain the methacrylic resin composition.
(13): a step of polymerizing a monomer constituting a polymer (b1) having a structural unit containing methacrylic acid as a main component, and a polymer (b2) having a structural unit containing acrylate as a main component (10) to (12), wherein the block copolymer (B) is produced by including the step of polymerizing the monomer constituting the block copolymer, and the block copolymer (B) is contained as the elastomer component [2]. Film manufacturing method.

The acrylic film of the present invention has high transparency, high glass transition temperature, chemical resistance, whitening resistance, and high surface hardness.

The acrylic film of the present invention comprises a methacrylic resin composition containing a methacrylic resin [1] and an elastomer component [2]. In other words, the acrylic film of the present invention comprises the methacrylic resin [1] and the elastomer component [2].

The methacrylic resin [1] has a syndiotacticity (rr) represented by triplets of 65% or more, preferably 70 to 90%, more preferably 72 to 85%. When the syndiotacticity is 65% or more, the glass transition temperature of the methacrylic resin composition of the present invention can be increased and the composition has excellent heat resistance. Further, it tends to have excellent chemical resistance.

Here, the syndiotacticity (rr) in the triplet display (hereinafter, may be simply referred to as “syndiotacticity (rr)”) is a chain of three consecutive structural units (triplet, It is a ratio in which the two chains (triple, diad) of the triad are both racemo (denoted as rr). In the chain (diad, diad) of the structural units in the polymer molecule, those having the same steric configuration are referred to as meso, and the opposite ones are referred to as racemo, and they are referred to as m and r, respectively. The syndiotacticity (rr) (%) represented by a triplet was measured by measuring a 1 H-NMR spectrum in deuterated chloroform at 30° C., and measuring 0.6 to 0. The area (X) of the region of 95 ppm and the area (Y) of the region of 0.6 to 1.35 ppm can be measured and calculated by the formula: (X/Y)×100.

The amount of the methacrylic resin [1] contained in the acrylic film of the present invention is preferably 60 to 99% by mass, more preferably 70 to 99% by mass from the viewpoint of achieving both a high glass transition temperature and good moldability. ˜99% by mass is more preferred. If it is less than 60% by mass, the surface hardness and rigidity of the acrylic film are lowered, which is not preferable. If it exceeds 99% by mass, toughness such as punching workability of the acrylic film is impaired, which is not preferable.

The weight average molecular weight (hereinafter sometimes simply referred to as “Mw”) of the methacrylic resin [1] is preferably 40,000 to 150,000, more preferably 40,000 to 120,000, and further preferably 50,000 to 100,000. If the Mw is less than 40,000, the toughness such as punching processability of the acrylic film tends to decrease, and if it exceeds 150000, film forming tends to be difficult and the process condition range tends to narrow.

The methacrylic resin [1] has a ratio (Mw/Mn; hereinafter, this value may be referred to as “molecular weight distribution”) of Mw and a number average molecular weight (hereinafter sometimes simply referred to as “Mn”). , Preferably 1.01 to 1.8, more preferably 1.03 to 1.5, and further preferably 1.05 to 1.3. When the methacrylic resin [1] having a molecular weight distribution within such a range is used, it becomes easy to obtain a molded product having excellent mechanical strength and particularly excellent mechanical properties and creep properties at high temperatures. Further, it becomes easy to obtain a film having excellent chemical resistance. Mw and Mn can be controlled by adjusting the type and amount of the polymerization initiator used in the production of the methacrylic resin [1]. Note that Mw and Mn are values obtained by converting a chromatogram measured by gel permeation chromatography (GPC) into a molecular weight of standard polystyrene.

The glass transition temperature of the methacrylic resin [1] is preferably 125° C. or higher, more preferably 128° C. or higher, still more preferably 130° C. or higher. The upper limit of the glass transition temperature of the methacrylic resin [1] is preferably 140°C. The glass transition temperature can be controlled by adjusting the molecular weight or syndiotacticity (rr). As the glass transition temperature of the methacrylic resin [1] becomes higher, the glass transition temperature of the obtained methacrylic resin composition becomes higher, and the acrylic film made of the methacrylic resin composition is less likely to undergo deformation such as heat shrinkage.

In the methacrylic resin [1], the content of the structural unit derived from methacrylic acid ester is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, still more preferably 99% by mass. As described above, most preferably 100% by mass. Examples of such methacrylic acid ester include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; methacrylic acid aryl esters such as phenyl methacrylate; cyclohexyl methacrylate and norbornenyl methacrylic acid cycloalkyl methacrylates. Ester; Of these, alkyl methacrylate is preferred, and methyl methacrylate is most preferred.

In the methacrylic resin [1], of the structural units derived from the above-mentioned methacrylic acid ester, the content of the structural unit derived from methyl methacrylate is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably Is 98% by mass or more, more preferably 99% by mass or more, and most preferably 100% by mass.

Examples of the structural unit other than the structural unit derived from the methacrylic acid ester that can be contained in the methacrylic resin [1] include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. Acrylic acid alkyl esters; Acrylic acid aryl esters such as phenyl acrylate; Acrylic acid cycloalkyl esters such as cyclohexyl acrylate and norbornenyl acrylate; Aromatic vinyl compounds such as styrene and α-methylstyrene; Acrylamide; Methacrylamide Structural units derived from vinyl monomers having only one polymerizable carbon-carbon double bond in one molecule such as acrylonitrile and methacrylonitrile.

There is no particular limitation on the method for producing the methacrylic resin [1]. From the viewpoint of productivity, a method for producing a methacrylic resin [1] by adjusting the polymerization temperature, the polymerization time, the type and amount of the chain transfer agent, the type and amount of the polymerization initiator in the anionic polymerization method is used. preferable.

As such an anionic polymerization method, for example, an anionic polymerization method using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid salt such as a salt of an alkali metal or an alkaline earth metal (see JP-B-7-25859), A method of performing anionic polymerization in the presence of an organic aluminum compound using an organic alkali metal compound as a polymerization initiator (see JP-A No. 11-335432), and a method of performing anion polymerization using an organic rare earth metal complex as a polymerization initiator (JP-A No. 6-93060). See) and the like.

In the anionic polymerization method for producing the methacrylic resin [1], it is preferable to use alkyllithium such as n-butyllithium, sec-butyllithium, isobutyllithium, and tert-butyllithium as a polymerization initiator. Further, from the viewpoint of productivity, it is preferable to coexist with an organoaluminum compound. The organic aluminum has the following formula:

AlR1R2R3 (in the formula, R1, R2 and R3 are each independently an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent) Represents an aralkyl group which may have a substituent, an alkoxyl group which may have a substituent, an aryloxy group which may have a substituent or an N,N-disubstituted amino group. And R3 may be an arylenedioxy group which may have a substituent and which is bonded to each other.

Specific examples of the organoaluminum compound include isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, isobutylbis(2,6-di-tert-butylphenoxy)aluminum, isobutyl[2,2]. '-Methylenebis(4-methyl-6-tert-butylphenoxy)] aluminum and the like. Further, in the anionic polymerization method, an ether, a nitrogen-containing compound or the like can be made to coexist for controlling the polymerization reaction.

It is important that the elastomer component [2] contained in the acrylic film of the present invention contains 30% by mass or more of the structural unit derived from an acrylate ester. If it is less than 30% by mass, the toughness of the resulting acrylic film is poor and chipping or cracking is likely to occur in a punching test or the like, which is not preferable. The content of the structural unit derived from the acrylate ester in the elastomer component [2] is preferably 35% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 80% by mass or less.

Examples of such acrylates include alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; aryl acrylates such as phenyl acrylate and benzyl acrylate; cyclohexyl acrylate and norbornenyl acrylate. Acrylic acid cycloalkyl ester; alkyl acrylate ester is preferable, and butyl acrylate is most preferable.

Examples of the structural unit other than the structural unit derived from the acrylate ester that may be contained in the elastomer component [2] include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. Methacrylic acid alkyl esters such as; Methacrylic acid aryl esters such as phenyl methacrylate; Methacrylic acid cycloalkyl esters such as cyclohexyl methacrylate and norbornenyl methacrylate; Aromatic vinyl compounds such as styrene and α-methylstyrene; Acrylamide; Methacrylic A structural unit derived from a vinyl-based monomer having only one polymerizable carbon-carbon double bond in one molecule such as amide; acrylonitrile; methacrylonitrile;

The form of dispersion of the disperse phase derived from the elastomer component [2] in the acrylic film of the present invention is not particularly limited, and examples thereof include a spherical shape, an ellipsoidal shape, a rod shape, a flat body shape, and a string shape. The size of the disperse phase derived from the elastomer component [2], particularly the size of the major axis of the disperse phase, is important because it affects the film performance such as transparency and bending whitening resistance. Therefore, it is important that the major axis size of the dispersed phase of the elastomer component [2] is 10 to 300 nm when the thin piece of the acrylic film of the present invention is phosphotungstic acid. The major axis size of the dispersed phase is measured by the following method.

Two thin pieces used for the measurement of phosphotungstic acid staining are prepared by the following method. A thin piece A is obtained by cutting with a microtome in the film thickness direction and in the film extrusion direction. A thin piece B is obtained by cutting with a microtome in the thickness direction of the film and in the vertical direction of extrusion. Slices A and B are each stained with a phosphotungstic acid solution and observed with a transmission electron microscope. In the thin piece A, 100 disperse phases dyed in the extrusion direction of the film are extracted, the major axis is averaged, and the average value of the major axis (A-Av) is determined. For the thin piece B, 100 disperse phases dyed in the direction perpendicular to the extrusion of the film are extracted, the major axis is averaged, and the average value of the major axis (B-Av) is determined. The larger one of the average value of major axis (A-Av) and the average value of major axis (B-Av) is defined as the major axis of the dispersed phase derived from the elastomer component [2]. By dyeing with phosphotungstic acid, butyl acrylate is particularly effectively dyed, and the state of the dispersed phase of the elastomer component [2] can be accurately grasped.

When the major axis size of the dispersed phase derived from the elastomer component [2] is less than 10 nm by the above-mentioned measuring method, the transparency is excellent, but it becomes brittle, which is not preferable. On the other hand, if it exceeds 300 nm, the transparency and the whitening property upon bending deteriorate, which is not preferable. The value is preferably 50 nm or more and 290 nm or less, more preferably 100 nm or more and 270 nm or less.

The amount of the elastomer component [2] contained in the acrylic film of the present invention is preferably 40 to 1% by mass, more preferably 30 to 1% by mass, and further preferably 20 to 1% by mass. If the elastomer component exceeds 40% by mass, the chemical resistance and heat resistance are deteriorated, which is not preferable. When the acrylic film of the present invention is stretched, punchability can be maintained even if the amount of the elastomer component [2] is reduced. Therefore, in the stretched acrylic film of the present invention, the content of the elastomer component [2] is preferably 1 to 20% by mass, more preferably 1 to 10% by mass.

The elastomer component [2] is not particularly limited as long as it contains 30% by mass or more of a structural unit derived from an acrylate ester, and includes a linear polymer, a core-shell type graft copolymer, and a soft block. Examples thereof include block copolymers composed of hard blocks, and a mixture thereof may be used. Of these, block copolymers composed of soft blocks and hard blocks, core-shell type graft copolymers, and mixtures thereof are preferable in that impact resistance and toughness can be imparted without impairing other physical properties.

The low temperature side glass transition temperature of the elastomer component [2] is preferably 20° C. or lower, and more preferably −20° C. or lower. When the temperature is 20° C. or higher, the toughness such as punching workability is deteriorated, which is not preferable.

The total amount of the methacrylic resin [1] and the elastomer component [2] contained in the acrylic film of the present invention is preferably 80% by mass or more, more preferably 85% by mass or more, further preferably 90% by mass or more, further more It is preferably 95% by mass or more, and most preferably 98.5% by mass or more.

The one obtained by kneading only the methacrylic resin [1] and the elastomer component [2] has a melt flow rate of preferably 0.1 g/10 minutes or more, more preferably 0.2 at 230° C. and a load of 3.8 kg. -30 g/10 min, more preferably 0.5-20 g/10 min, most preferably 1.0-10 g/10 min.

Further, the one obtained by kneading only the methacrylic resin [1] and the elastomer component [2] has a glass transition temperature of preferably 120° C. or higher, more preferably 123° C. or higher, further preferably 124° C. or higher, and most preferably 130. ℃ or above.

A block copolymer, which is a preferred embodiment of the elastomer component [2] used in the present invention, will be described.

The block copolymer (B) that can be used as the elastomer component [2] used in the present invention is a block copolymer having a methacrylic acid ester polymer block (b1) and an acrylic acid ester polymer block (b2). The block copolymer (B) may have only one methacrylic acid ester polymer block (b1) or may have a plurality thereof. Further, the block copolymer (B) may have only one acrylic acid ester polymer block (b2) or may have a plurality thereof.

The methacrylic acid ester polymer block (b1) is a polymer having a structural unit containing methacrylic acid ester as a main component. The proportion of structural units derived from methacrylic acid ester in the methacrylic acid ester polymer block (b1) is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, particularly preferably 98% by mass. % Or more.

Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, and methacrylic acid. Amyl acid, isoamyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, methacrylic acid 2-hydroxyethyl, 2-methoxyethyl methacrylate, glycidyl methacrylate, allyl methacrylate, etc. can be mentioned. Among these, from the viewpoint of improving transparency and heat resistance, methacrylic acid such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate and isobornyl methacrylate. Alkyl esters are preferred, and methyl methacrylate is more preferred. The methacrylic acid ester polymer block (b1) can be formed by polymerizing these methacrylic acid esters alone or in combination of two or more.

The methacrylic acid ester polymer block (b1) may contain a structural unit derived from a monomer other than the methacrylic acid ester as long as it does not hinder the objects and effects of the present invention. The proportion of structural units derived from monomers other than methacrylic acid ester contained in the methacrylic acid ester polymer block (b1) is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass. The range is particularly preferably 2% by mass or less.

Examples of the monomers other than the methacrylic acid ester include acrylic acid ester, unsaturated carboxylic acid, aromatic vinyl compound, olefin, conjugated diene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, vinyl pyridine, Examples thereof include vinyl ketone, vinyl chloride, vinylidene chloride, vinylidene fluoride and the like. The methacrylic acid ester polymer block (b1) can be formed by copolymerizing these monomers other than the methacrylic acid ester alone or in combination of two or more kinds with the above-mentioned methacrylic acid ester.

The methacrylic acid ester polymer block (b1) is preferably composed of a polymer having a refractive index in the range of 1.485 to 1.495 from the viewpoint of increasing the transparency of the methacrylic resin composition.

The weight average molecular weight of the methacrylic acid ester polymer block (b1) is preferably 5,000 or more and 150,000 or less, more preferably 8,000 or more and 120,000 or less, and even more preferably 12,000 or more and 100,000 or less. Is.

When the block copolymer (B) has a plurality of methacrylic acid ester polymer blocks (b1), the composition ratios and molecular weights of the structural units constituting the respective methacrylic acid ester polymer blocks (b1) are the same as each other. It can be different or different.

When there are a plurality of methacrylic acid ester polymer blocks (b1), the maximum weight average molecular weight Mw(b1) among them is preferably 12,000 or more and 150,000 or less, more preferably 15,000 or more and 120,000 or less, More preferably, it is 20,000 or more and 100,000 or less. When the block copolymer (B) has only one methacrylic acid ester polymer block (b1), the weight average molecular weight of the methacrylic acid ester polymer block (b1) is Mw(b1). When the block copolymer (B) has a plurality of methacrylic acid ester polymer blocks (b1), and the plurality of methacrylic acid ester polymer blocks (b1) have the same weight average molecular weight. Has a weight average molecular weight of Mw(b1).

In the methacrylic resin composition used in the present invention, the ratio of the weight average molecular weight Mw[1] of the methacrylic resin [1] to Mw(b1), that is, Mw[1]/Mw(b1) is 0.5 or more.2. It is 5 or less, preferably 0.6 or more and 2.3 or less, and more preferably 0.7 or more and 2.2 or less. When Mw[1]/Mw(b1) is less than 0.5, impact resistance and surface smoothness of the acrylic film produced from the methacrylic resin composition tend to be lowered. On the other hand, when Mw[1]/Mw(b1) is too large, the surface smoothness and the temperature dependence of haze of the molded article produced from the methacrylic resin composition tend to be deteriorated. When Mw[1]/Mw(b1) is within the above range, the size of the dispersed phase in the methacrylic resin (A) of the block copolymer (B) becomes small, so that the haze is low regardless of temperature change. Therefore, it is considered that the change in haze becomes small over a wide temperature range.

The proportion of the methacrylic acid ester polymer block (b1) in the block copolymer (B) is preferably 40% by mass or more and 90% by mass or less from the viewpoint of transparency, flexibility, moldability and surface smoothness. It is preferably 45% by mass or more and 80% by mass or less. When the ratio of the methacrylic acid ester polymer block (b1) in the block copolymer (B) is within the above range, the methacrylic resin composition of the present invention or a molded article made of the same has transparency, flexibility and flex resistance. Excellent in impact resistance and flexibility. When the block copolymer (B) contains a plurality of methacrylic acid ester polymer blocks (b1), the above ratio is calculated based on the total mass of all the methacrylic acid ester polymer blocks (b1).

The acrylic acid ester polymer block (b2) is a polymer having a structural unit containing acrylic acid ester as a main component. The proportion of the structural unit derived from an acrylic ester in the acrylic ester polymer block (b2) is preferably 45% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, particularly preferably 90% by mass. % Or more.

Examples of the acrylic ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, and acrylic. Amyl acid, isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, acrylic acid 2-hydroxyethyl, 2-methoxyethyl acrylate, glycidyl acrylate, allyl acrylate and the like can be mentioned. The acrylic acid ester polymer block (b2) can be formed by polymerizing these acrylic acid esters alone or in combination of two or more.

The acrylic acid ester polymer block (b2) may contain a structural unit derived from a monomer other than the acrylic acid ester, as long as the objects and effects of the present invention are not impaired. The proportion of structural units derived from monomers other than acrylic acid ester contained in the acrylic acid ester polymer block (b2) is preferably 55% by mass or less, more preferably 50% by mass or less, and further preferably 40% by mass. Hereafter, it is particularly preferably 10% by mass or less.

As the monomer other than the acrylic acid ester, methacrylic acid ester, unsaturated carboxylic acid, aromatic vinyl compound, olefin, conjugated diene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, vinyl pyridine, vinyl ketone, Examples thereof include vinyl chloride, vinylidene chloride and vinylidene fluoride. The acrylic acid ester polymer block (b2) can be formed by copolymerizing these monomers other than the acrylic acid ester alone or in combination of two or more kinds with the above-mentioned acrylic acid ester.

The acrylic acid ester polymer block (b2) is used for the purpose of adjusting the refractive index of the methacrylic resin composition used in the present invention and improving the transparency, and the like. It is preferably composed of a group ester. Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and the like. Of these, n-butyl acrylate and 2-ethylhexyl acrylate are preferable.

The (meth)acrylic acid aromatic ester means an acrylic acid aromatic ester or a methacrylic acid aromatic ester, and is composed of a compound containing an aromatic ring ester-bonded to (meth)acrylic acid. Examples of such (meth)acrylic acid aromatic ester include phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, styryl acrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, and styryl methacrylate. To be Among them, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate and benzyl acrylate are preferable. When the acrylic acid ester polymer block (b2) is composed of an acrylic acid alkyl ester and a (meth)acrylic acid aromatic ester, the acrylic acid ester polymer block (b2) is a structural unit derived from an acrylic acid alkyl ester. It is preferable to contain 50 to 90% by mass and 50 to 10% by mass of the structural unit derived from (meth)acrylic acid aromatic ester, and 60 to 80% by mass of the structural unit derived from alkyl acrylate and (meth)acrylic. It is more preferable to contain 40 to 20 mass% of structural units derived from an acid aromatic ester.

From the viewpoint of increasing the transparency of the methacrylic resin composition used in the present invention, the acrylic ester polymer block (b2) is composed of a polymer having a refractive index in the range of 1.485 to 1.495. preferable.

The weight average molecular weight of the acrylic acid ester polymer block (b2) is 5,000 or more and 120,000 or less, preferably 15,000 or more and 110,000 or less, and more preferably 30,000 or more and 100,000 or less.

When the block copolymer (B) has a plurality of acrylic acid ester polymer blocks (b2), the composition ratios and molecular weights of the structural units constituting the respective acrylic acid ester polymer blocks (b2) are the same as each other. It can be different or different.

When there are a plurality of acrylic acid ester polymer blocks (b2), the maximum weight average molecular weight Mw(b2) among them is 30 0 0 0 0 or more and 1 2 0 0 0 0 0 or less, preferably 40 0 0 0 0. The above is 1 1 0, 0 0 0 0 or less, more preferably 5 0, 0 0 0 or more and 1 0 0, 0 0 0 0 0 or less. When Mw(b2) is small, the impact resistance of the acrylic film produced from the methacrylic resin composition tends to be lowered. On the other hand, when Mw(b2) is large, the surface smoothness of the molded article produced from the methacrylic resin composition tends to be lowered. If having only one block copolymer (B) A acrylic acid ester polymer block in (b2), the weight average molecular weight of the A acrylic acid ester polymer block (b2) is Mw (b2). Further, in a case where a plurality of A acrylic acid ester polymer block (b 2) in the block copolymer (B), the weight average molecular weight of the plurality of A acrylic acid ester polymer block (b 2) with each other When they are the same, the weight average molecular weight is Mw(b2).

The weight average molecular weight of the methacrylic acid ester polymer block (b1) and the weight average molecular weight of the acrylic acid ester polymer block (b2) are sampled during and after the polymerization in the process of producing the block copolymer (B). Is a value calculated from the weight average molecular weights of the intermediate product and the final product (block copolymer (B)) measured by carrying out. Each weight average molecular weight is a standard polystyrene conversion value measured by GPC (gel permeation chromatography).

The proportion of the acrylic acid ester polymer block (b2) in the block copolymer (B) is preferably 10% by mass or more and 60% by mass or less from the viewpoint of transparency, flexibility, moldability and surface smoothness. It is preferably 20% by mass or more and 55% by mass or less. When the proportion of the acrylic acid ester polymer block (b2) in the block copolymer (B) is within the above range, the methacrylic resin composition of the present invention or a molded product made from the same has excellent impact resistance and flexibility. When the block copolymer (B) contains a plurality of acrylic acid ester polymer blocks (b2), the above ratio is calculated based on the total mass of all the acrylic acid ester polymer blocks (b2).

The block copolymer (B) is not particularly limited depending on the bonding form of the methacrylic acid ester polymer block (b1) and the acrylic acid ester polymer block (b2). For example, a methacrylic acid ester polymer block (b1) having one end connected to one end of an acrylic acid ester polymer block (b2) (diblock copolymer having a (b1)-(b2) structure); methacrylic acid One in which one end of the acrylic acid ester polymer block (b2) is connected to each of both ends of the ester polymer block (b1) (a triblock copolymer having a (b2)-(b1)-(b2) structure); One in which one end of the methacrylic acid ester polymer block (b1) is connected to each of both ends of the acrylic acid ester polymer block (b2) ((b1)-(b2)-(b1) structure triblock copolymer And a block copolymer having a structure in which a methacrylic acid ester polymer block (b1) and an acrylic acid ester polymer block (b2) are connected in series.

In addition, a block copolymer ([(b1)-(b2)-]nX structure) in which one end of a plurality of block copolymers having a (b1)-(b2) structure is connected to form a radial structure; b2)-(b1) block copolymer having one end connected to form a radial structure ([(b2)-(b1)-]nX structure); a plurality of (b1)-(b2) )-(B1) block copolymer having one end connected to form a radial structure block copolymer ([(b1)-(b2)-(b1)-]nX structure); a plurality of (b2) Stars such as a block copolymer ([(b2)-(b1)-(b2)-]nX structure) in which one end of a block copolymer having a -(b1)-(b2) structure is connected to form a radial structure Examples of the block copolymer include block copolymers having a branched structure. In addition, X represents a coupling agent residue here. Of these, diblock copolymers, triblock copolymers and star block copolymers are preferable, and diblock copolymers having a (b1)-(b2) structure, (b1)-(b2)-(b1 ) Structure triblock copolymer, [(b1)-(b2)-]nX structure star block copolymer, [(b1)-(b2)-(b1)-]nX structure star block copolymer Polymers are more preferred.

Further, the block copolymer (B) may have a polymer block (b3) other than the methacrylic acid ester polymer block (b1) and the acrylic acid ester polymer block (b2). The main structural unit constituting the polymer block (b3) is a structural unit derived from a monomer other than methacrylic acid ester and acrylic acid ester. Examples of such a monomer include olefins such as ethylene, propylene, 1-butene, isobutylene and 1-octene; conjugated dienes such as butadiene, isoprene and myrcene; styrene, α-methylstyrene, p-methylstyrene, m- Aromatic vinyl compounds such as methylstyrene; vinyl acetate, vinyl pyridine, acrylonitrile, methacrylonitrile, vinyl ketone, vinyl chloride, vinylidene chloride, vinylidene fluoride, acrylamide, methacrylamide, ε-caprolactone, valerolactone, etc. ..

In the block copolymer (B), the bonding form of the methacrylic acid ester polymer block (b1), the acrylic acid ester polymer block (b2) and the polymer block (b3) is not particularly limited. The binding form of the block copolymer (B) comprising the methacrylic acid ester polymer block (b1), the acrylic acid ester polymer block (b2) and the polymer block (b3) is, for example, (b1)-(b2). Examples thereof include a block copolymer having a -(b1)-(b3) structure and a block copolymer having a (b3)-(b1)-(b2)-(b1)-(b3) structure. When there are a plurality of polymer blocks (b3) in the block copolymer (B), the composition ratios and molecular weights of the structural units constituting the respective polymer blocks (b3) may be the same as each other, May be different.

The block copolymer (B) may have a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride or an amino group in the molecular chain or at the terminal of the molecular chain, if necessary.

The weight average molecular weight Mw(B) of the block copolymer (B) is preferably 52,000 or more and 400,000 or less, more preferably 60,000 or more and 300,000 or less. When the weight average molecular weight of the block copolymer (B) is small, sufficient melt tension cannot be maintained in melt extrusion molding, a good acrylic film is difficult to obtain, and the breaking strength of the obtained acrylic film is small. Mechanical properties tend to deteriorate. On the other hand, when the weight average molecular weight of the block copolymer (B) is large, the viscosity of the molten resin becomes high, and the surface of the acrylic film obtained by melt extrusion molding has fine grain-like irregularities and unmelted matter (high molecular weight). The solid particles tend to cause lumps, making it difficult to obtain a good plate-shaped molded product.

The molecular weight distribution of the block copolymer (B) is preferably 1.01 or more and 2.00 or less, more preferably 1.05 or more and 1.60 or less. By having a molecular weight distribution within such a range, the content of the unmelted material that causes the generation of lumps in the acrylic film of the present invention can be made extremely small. The molecular weight distribution is the ratio of the weight average molecular weight to the number average molecular weight, and is the value determined from the molecular weight in terms of standard polystyrene measured by GPC (gel permeation chromatography).

The refractive index of the block copolymer (B) is preferably 1.485 to 1.495, more preferably 1.487 to 1.493. When the refractive index is within this range, the methacrylic resin composition has high transparency. In the present specification, the “refractive index” means a value measured at a measurement wavelength of 587.6 nm (d line), as in Examples described later.

The method for producing the block copolymer (B) is not particularly limited, and a method according to a known method can be adopted. For example, a method of subjecting the monomers constituting each polymer block to living polymerization is generally used. Examples of such a living polymerization method include a method of anionic polymerization in the presence of a mineral acid salt such as an alkali metal or alkaline earth metal salt using an organic alkali metal compound as a polymerization initiator, and a method of polymerizing an organic alkali metal compound. A method of anionic polymerization in the presence of an organoaluminum compound used as an initiator, a method of polymerization using an organic rare earth metal complex as a polymerization initiator, and a method of radical polymerization in the presence of a copper compound using an α-halogenated ester compound as an initiator. And so on. In addition, a method for producing a mixture containing the block copolymer (B) used in the present invention by polymerizing the monomers constituting each block using a polyvalent radical polymerization initiator or a polyvalent radical chain transfer agent, etc. Can also be mentioned. Among these methods, in particular, the block copolymer (B) can be obtained in high purity, the molecular weight and composition ratio can be easily controlled, and it is economical. A method of anionic polymerization in the presence of an organoaluminum compound is preferred.

Next, a core-shell type graft copolymer, which is a preferred embodiment as the elastomer component [2] used in the present invention, will be described. The laminated structure of the core-shell type graft copolymer is not particularly limited as long as it has an outermost layer and an inner layer. For example, a core (inner layer) is a two-layer polymer particle in which a crosslinked rubber polymer (I)-outer shell (outermost layer) is a thermoplastic polymer (II), and a core (inner layer) is a polymer (III)-inner shell ( The inner layer) is a three-layer polymer particle in which the crosslinked rubber polymer (I)-outer shell (outermost layer) is the thermoplastic polymer (II), and the core (inner layer) is the crosslinked rubber polymer (I)-first inner shell ( Various layers such as 4-layer polymer particles in which the inner layer is a polymer (III)-the second inner shell (inner layer) is a crosslinked rubber polymer (I)-the outer shell (outermost layer) is a thermoplastic polymer (II) Structure is possible. Among these, three-layer polymer particles in which the core (inner layer) is polymer (III)-inner shell (inner layer) is crosslinked rubber polymer (I)-outer shell (outermost layer) is thermoplastic polymer (II) Preferred; 80 to 99.95% by mass of methyl methacrylate, 0 to 19.95% by mass of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms, and a crosslinkable monomer. A layer containing the polymer (III) obtained by polymerizing 0.05 to 2% by mass, wherein the inner shell (inner layer) has an alkyl group having 1 to 8 carbon atoms. A layer containing a crosslinked rubber polymer (I) obtained by polymerizing 80 to 98% by mass, 1 to 19% by mass of an aromatic vinyl monomer and 1 to 5% by mass of a crosslinkable monomer. Thermoplastic polymer (II) obtained by polymerizing 80 to 100% by mass of methyl methacrylate and 0 to 20% by mass of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms in the shell (outermost layer). A three-layer polymer particle composed of a layer containing is more preferable. From the viewpoint of transparency of the core-shell type graft copolymer, each layer is such that the difference in refractive index between adjacent layers is preferably less than 0.005, more preferably less than 0.004, and further preferably less than 0.003. It is preferable to select the polymer contained in.

The mass ratio of the inner layer to the outermost layer in the core-shell type graft copolymer is preferably 60/40 to 95/5, more preferably 70/30 to 90/10. The proportion of the layer containing the crosslinked rubber polymer (I) in the inner layer is preferably 20 to 70% by mass, more preferably 30 to 50% by mass.

The average particle size of the core-shell type graft copolymer is preferably 0.05 to 1 μm, more preferably 0.07 to 0.5 μm, and further preferably 0.10 to 0.4 μm. When a core-shell type graft copolymer having an average particle size within such a range, particularly 0.15 to 0.3 μm, is used, toughness can be expressed with a small amount of compounding, and therefore rigidity is increased. And surface hardness. In addition, the average particle diameter in this specification is an arithmetic average value in a volume-based particle diameter distribution measured by a light scattering light method.

The method for producing the core-shell type graft copolymer is not particularly limited, but the emulsion polymerization method is preferable. Specifically, it can be obtained by emulsion-polymerizing a monomer constituting the crosslinked rubber polymer (I). Further, the core-shell type graft copolymer as a crosslinked rubber particle component, to obtain seed particles by emulsion polymerization of the monomers constituting the innermost layer of the core-shell type graft copolymer, each layer in the presence of this seed particle It can be obtained by sequentially adding the monomers constituting the above and successively polymerizing up to the outermost layer.

Examples of the emulsifier used in the emulsion polymerization method include anionic emulsifiers such as sodium dioctylsulfosuccinate, dialkylsulfosuccinates such as sodium dilaurylsulfosuccinate, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, etc. Alkylsulfate; nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene nonyl phenyl ether; nonionic anion emulsifiers such as polyoxyethylene nonyl phenyl ether sulfate sodium polyoxyethylene nonyl phenyl ether sulfate, And polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene alkyl ether sulfate, and alkyl ether carboxylates such as sodium polyoxyethylene tridecyl ether acetate. You may use these individually by 1 type or in combination of 2 or more type. The average number of repeating units of ethylene oxide units in the nonionic emulsifier and nonionic anionic emulsifier exemplified compounds is preferably 30 or less, more preferably 20 or less, in order to prevent the foamability of the emulsifier from becoming extremely large. More preferably, it is 10 or less.

The polymerization initiator used for emulsion polymerization is not particularly limited. Examples thereof include persulfate initiators such as potassium persulfate and ammonium persulfate; and redox initiators such as persulfoxylate/organic peroxide and persulfate/sulfite.

Separation and acquisition of the core-shell type graft copolymer from the polymer latex obtained by emulsion polymerization can be performed by a known method such as a salting-out coagulation method, a freeze coagulation method, or a spray drying method. Among these, the salting out coagulation method and the freeze coagulation method are preferable, and the freeze coagulation method is more preferable, since impurities contained in the crosslinked rubber particle component can be easily removed by washing with water. Since no coagulant is used in the freeze-coagulation method, an acrylic resin film having excellent water resistance can be easily obtained. In order to remove foreign substances mixed in the polymer latex before the coagulation step, it is preferable to filter the polymer latex with a wire mesh having an opening of 50 μm or less. From the viewpoint of being easily uniformly dispersed in the melt-kneading with the methacrylic resin [1], the core-shell type graft copolymer is preferably taken out as aggregated particles of 1000 μm or less, and more preferably taken out as aggregated particles of 500 μm or less. The form of the agglomerated particles is not particularly limited, and may be, for example, a pellet-like state in which the outermost layer portions are fused to each other, or a powder-like or granule-like powder.

As the elastomer component [2] used in the present invention, the block copolymer (B) described above and the core-shell type graft copolymer can be used in combination.

The components other than the methacrylic resin [1] and the elastomer component [2] that may be contained in the acrylic film of the present invention include other polymers, fillers, antioxidants, heat deterioration inhibitors, ultraviolet absorbers, and light. Additives such as stabilizers, lubricants, release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, light diffusers, organic dyes, matting agents, impact modifiers, and phosphors. Can be mentioned. These may be added to either or both of the polymerization reaction liquids for producing the methacrylic resin [1] or the elastomer component [2], or the methacrylic resin [1] or the methacrylic resin produced by the polymerization reaction. It may be added to either or both of [2], or may be added to a kneaded product with the methacrylic resin [1] or the elastomer component [2].

Examples of other polymers include methacrylic resins other than methacrylic resin [1], polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, polynorbornene; ethylene ionomers; polystyrene, styrene-anhydrous. Styrene resin such as maleic acid copolymer, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin and MBS resin; methyl methacrylate polymer, methyl methacrylate-styrene copolymer; polyethylene terephthalate, Polyester resin such as polybutylene terephthalate; nylon 6, nylon 66, polyamide such as polyamide elastomer; polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacetal, polyvinylidene fluoride, polyurethane, modified Polyphenylene ether, polyphenylene sulfide, silicone modified resin, polyvinyl butyral resin, polyacetoacetal resin; elastomer component other than elastomer component [2], silicone rubber; styrene thermoplastic elastomer such as SEPS, SEBS, SIS; IR, EPR, EPDM Examples include olefin rubber and the like. The amount of the other polymer that can be contained in the methacrylic resin composition of the present invention is preferably 10% by mass or less based on 100 parts by mass of the total amount of the methacrylic resin [1] and the elastomer component [2].

The methacrylic resin composition according to a preferred embodiment of the present invention contains a polycarbonate resin, a phenoxy resin, a polyester resin, a polyvinyl butyral resin, and a polyacetoacetal resin in addition to the methacrylic resin [1] and the elastomer component [2]. It is a thing. By containing a polycarbonate resin, a phenoxy resin, a polyester resin, a polyvinyl butyral resin, and a polyacetoacetal resin, the retardation of the acrylic film can be adjusted. The amount of the polycarbonate resin, the phenoxy resin, the polyester resin, the polyvinyl butyral resin, and the polyacetoacetal resin is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the methacrylic resin [1] and the elastomer component [2]. It is more preferably 2 to 7 parts by mass, further preferably 3 to 6 parts by mass.

A methacrylic resin composition according to a more preferred embodiment of the present invention contains a methacrylic resin [1], an elastomer component [2], and a polycarbonate resin. The polycarbonate resin used in the present invention is preferably an aromatic polycarbonate resin from the viewpoint of compatibility. Polycarbonate resin is a polymer obtained by the reaction of a polyfunctional hydroxy compound and a carbonic acid ester forming compound. From the viewpoint of easily reducing the phase difference of the molded product, the amount of the polycarbonate resin is preferably 1 to 10 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the total amount of the methacrylic resin [1] and the elastomer component [2]. Is 2 to 7 parts by mass, more preferably 3 to 6 parts by mass.

The aromatic polycarbonate resin used in the present invention is not particularly limited depending on its production method. For example, a phosgene method (interfacial polymerization method), a melt polymerization method (transesterification method) and the like can be mentioned. Further, the aromatic polycarbonate resin preferably used in the present invention may be one obtained by subjecting a polycarbonate resin produced by a melt polymerization method to a post-treatment for adjusting the amount of terminal hydroxy groups.

The aromatic polycarbonate resin used in the present invention preferably has a MVR value at 300° C. and 1.2 Kg of preferably 80 to 300 from the viewpoint of easily controlling the retardation to a desired value and obtaining a molded article having excellent transparency. 400 cm3/10 minutes, more preferably 100-300 cm3/10 minutes, even more preferably 130-250 cm3/10 minutes, most preferably 150-230 cm3/10 minutes, measured by gel permeation chromatography (GPC). A polycarbonate resin having a weight average molecular weight of the obtained chromatogram converted to the molecular weight of standard polystyrene is preferably 13000 to 32000, more preferably 14000 to 30000, still more preferably 15000 to 28000, and most preferably 18000 to 27,000. .. The MVR value or the molecular weight of the polycarbonate resin can be adjusted by adjusting the amounts of the terminal terminator and the branching agent.

Examples of the filler include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate and magnesium carbonate. The amount of filler that can be contained in the acrylic film of the present invention is preferably 3% by mass or less, more preferably 1.5% by mass or less.

The antioxidant alone has an effect of preventing oxidative deterioration of the resin in the presence of oxygen. Examples thereof include phosphorus-based antioxidants, hindered phenol-based antioxidants and thioether-based antioxidants. These antioxidants may be used alone or in combination of two or more. Among them, from the viewpoint of preventing deterioration of optical properties due to coloring, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferable, and combined use of phosphorus-based antioxidants and hindered phenol-based antioxidants is more preferable. When the phosphorus-based antioxidant and the hindered phenol-based antioxidant are used in combination, the usage amount of the phosphorus-based antioxidant:hindered phenol-based antioxidant is 1:5 to 2: by mass ratio. 1 is preferable, and 1:2 to 1:1 is more preferable.

As the phosphorus-based antioxidant, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite (manufactured by ADEKA; trade name: ADEKA STAB HP-10), tris(2,4-di-t-). Butylphenyl)phosphite (manufactured by BASF; trade name: IRGAFOS168) and the like are preferable.

As a hindered phenolic antioxidant, pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF; trade name IRGANOX1010), octadecyl-3-( 3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF; trade name IRGANOX1076) and the like are preferable.

The heat deterioration inhibitor is capable of preventing heat deterioration of the resin by trapping polymer radicals generated when exposed to high heat under a substantially oxygen-free condition. As the thermal deterioration inhibitor, 2-t-butyl-6-(3'-t-butyl-5'-methyl-hydroxybenzyl)-4-methylphenyl acrylate (Sumitomo Chemical Co., Ltd.; trade name Sumilizer GM), 2,4-di t-amyl-6-(3′,5′-di t-amyl-2′-hydroxy-α-methylbenzyl)phenyl acrylate (Sumitomo Chemical Co.; trade name Sumilizer GS) and the like are preferable.

A UV absorber is a compound that has the ability to absorb UV light. The ultraviolet absorber is a compound which is said to have a function of mainly converting light energy into heat energy. Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic esters, and formamidines. These may be used alone or in combination of two or more. Among these, benzotriazoles, triazines, or ultraviolet absorbers having a maximum molar absorption coefficient εmax at a wavelength of 380 to 450 nm of 1200 dm3·mol-1 cm-1 or less are preferable.

Benzotriazoles are highly effective in suppressing deterioration of optical properties such as coloring due to exposure to ultraviolet rays, and are therefore preferred as ultraviolet absorbers used when the methacrylic resin composition of the present invention is applied to applications requiring such properties. As benzotriazoles, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF; trade name TINUVIN329), 2-(2H- Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (manufactured by BASF; trade name TINUVIN234) and the like are preferable.

Further, an ultraviolet absorber having a maximum molar extinction coefficient εmax of 1200 dm3·mol-1 cm-1 or less at a wavelength of 380 to 450 nm can suppress the yellow tint of the obtained molded product. Examples of such an ultraviolet absorber include 2-ethyl-2'-ethoxy-oxalanilide (manufactured by Clariant Japan Ltd.; trade name: Sandeuboa VSU). Among these UV absorbers, benzotriazoles are preferably used from the viewpoint of suppressing resin deterioration due to UV irradiation.

Further, when it is desired to efficiently absorb a wavelength around 380 nm, a triazine-type ultraviolet absorber is preferably used. As such an ultraviolet absorber, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (made by ADEKA; LA-F70), 2 , 4-bis(2-hydroxy-4-butyroxyphenyl)-6-2,4-bis-butyroxyphenyl)-1,3,5-triazine and other hydroxyphenyltriazine-based UV absorbers (manufactured by BASF) TINUVIN460, TINUVIN479), and the like.

Furthermore, when it is desired to particularly effectively absorb light having a wavelength of 380 nm to 400 nm, WO2011-089794, WO2012-124395, JP2012-012476, JP2013-023461, JP2013-112790, JP2013-194037, It is preferable to use a metal complex containing a heterocomposite ring having a specific structure described in JP-A-2014-62228, JP-A-2014-88542, JP-A-2014-88543 and the like as an ultraviolet absorber. Examples of the heterocyclic ring having a specific structure include 2,2′-iminobisbenzothiazole, 2-(2-benzothiazolylamino)benzoxazole, 2-(2-benzothiazolylamino)benzimidazole, and (2- Examples thereof include benzothiazolyl)(2-benzimidazolyl)methane, bis(2-benzoxazolyl)methane, bis(2-benzothiazolyl)methane, bis[2-(N-substituted)benzimidazolyl]methane and derivatives thereof. As the central metal of such a metal complex, copper, nickel, cobalt and zinc are preferably used. Further, these metal complexes are preferably used in the state of a composition in which they are dispersed in a medium (low molecular weight compound or polymer) for dispersing the metal complex.

The addition amount of such a metal complex is preferably 0.01 parts by mass to 5 parts by mass, and 0.1 to 100 parts by mass with respect to the total of 100 parts by mass of the methacrylic resin [1] and the elastomer component [2] of the present invention. 2 parts by mass is more preferred. Since such a metal complex has a large molar extinction coefficient at a wavelength of 380 nm to 400 nm, the addition amount can be reduced. Since the addition amount can be reduced, it is possible to prevent the appearance of a molded product such as a film from being deteriorated due to bleeding out. Further, since it has high heat resistance, it is less likely to deteriorate or decompose during molding, and has high light resistance, so that the performance can be maintained for a long period of time.

The maximum value εmax of the molar absorption coefficient of the ultraviolet absorber is measured as follows. To 1 L of cyclohexane, 10.00 mg of the ultraviolet absorber is added and dissolved so that there is no undissolved substance by visual observation. This solution is poured into a 1 cm x 1 cm x 3 cm quartz glass cell, and the absorbance at a wavelength of 380 to 450 nm is measured using a U-3410 type spectrophotometer manufactured by Hitachi, Ltd. The maximum value εmax of the molar absorption coefficient is calculated by the following formula from the molecular weight (MUV) of the ultraviolet absorber and the maximum value (Amax) of the measured absorbance.

εmax=[Amax/(10×10 −3)]×MUV

The light stabilizer is a compound which is said to have a function of trapping radicals mainly generated by oxidation by light. Suitable light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton.

Examples of the lubricant include stearic acid, behenic acid, stearamic acid, methylenebisstearamide, hydroxystearic acid triglyceride, paraffin wax, ketone wax, octyl alcohol, hardened oil and the like.

Examples of the release agent include higher alcohols such as cetyl alcohol and stearyl alcohol; glycerin higher fatty acid esters such as stearic acid monoglyceride and stearic acid diglyceride. In the present invention, it is preferable to use higher alcohols and glycerin fatty acid monoester together as a release agent. When the higher alcohols and the glycerin fatty acid monoester are used in combination, the ratio thereof is not particularly limited, but the usage ratio of the higher alcohols: the usage amount of the glycerin fatty acid monoester is 2.5:1 to 3. 5:1 is preferable and 2.8:1 to 3.2:1 is more preferable.

As the polymer processing aid, polymer particles having a particle size of 0.05 to 0.5 μm, which can be produced by an emulsion polymerization method, are usually used. The polymer particles may be single-layer particles composed of a polymer having a single composition ratio and a single intrinsic viscosity, or may be multi-layer particles composed of two or more polymers having a different composition ratio or an intrinsic viscosity. May be. Among these, particles having a two-layer structure having a polymer layer having a low intrinsic viscosity in the inner layer and a polymer layer having a high intrinsic viscosity of 5 dl/g or more in the outer layer are preferable. The polymer processing aid preferably has an intrinsic viscosity of 3 to 6 dl/g. If the intrinsic viscosity is too small, the effect of improving moldability tends to be low. If the intrinsic viscosity is too high, the molding processability of the methacrylic resin composition tends to deteriorate.

As the organic dye, a compound having a function of converting ultraviolet rays into visible rays is preferably used.

Examples of the light diffusing agent and matting agent include glass fine particles, polysiloxane-based crosslinked fine particles, crosslinked polymer fine particles, talc, calcium carbonate and barium sulfate.

Examples of the fluorescent substance include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent whitening agents, and fluorescent bleaching agents.

May be contained in the acrylic film of the present invention, antioxidants, heat deterioration inhibitors, ultraviolet absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, The total amount of the light diffusing agent, the organic dye, the matting agent, the impact resistance modifier, and the phosphor is preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 4% by mass or less. ..

The method for producing the methacrylic resin composition that constitutes the acrylic film of the present invention is not particularly limited. For example, a methacrylic resin composition can be produced by melt-kneading the methacrylic resin [1], the elastomer component [2], and another polymer such as a polycarbonate resin. The melt-kneading can be performed using a melt-kneading device such as a kneader ruder, extruder, mixing roll, Banbury mixer, or the like. The temperature at the time of kneading may be appropriately adjusted depending on the softening temperatures of the methacrylic resin [1], the elastomer component [2] and the other polymer, but the kneading is usually performed at a temperature in the range of 150°C to 300°C.

As another method for producing a methacrylic resin composition, a methacrylic resin composition is produced by polymerizing a monomer as a raw material of an elastomer component [2] in the presence of a methacrylic resin [1] and another polymer. There is a way. Such polymerization can be carried out in the same manner as the polymerization method for producing the methacrylic resin [2]. The production method by polymerizing the monomer which is a raw material of the elastomer component [2] in the presence of the methacrylic resin [1] and the other polymer is a methacrylic resin [1], an elastomer component [2] and another polymer. Compared with the method of manufacturing by melting and kneading the coalesced product, the thermal history applied to the methacrylic resin becomes shorter, so that the thermal decomposition of the methacrylic resin is suppressed, and a molded product with less coloring and less foreign matter is easily obtained.

The acrylic film of the present invention can be produced by a solution casting method, a melt casting method, an extrusion molding method, an inflation molding method, a blow molding method, or the like. Of these, the extrusion molding method is preferable from the viewpoint that a film having excellent transparency, improved toughness, handleability, and excellent balance between toughness and surface hardness and rigidity can be obtained. The temperature of the methacrylic resin composition discharged from the extruder is preferably set to 200 to 300°C, more preferably 250 to 280°C.

Among the extrusion molding methods, the methacrylic resin composition is extruded from a T-die in a molten state from the viewpoint that a film having good surface smoothness, good specular gloss, and low haze can be obtained, and then it is applied to two or more specular rolls. Alternatively, a method of sandwiching and shaping with a mirror belt or a combination thereof is preferable.

The mirror surface roll is preferably a normal metal rigid body roll or a metal elastic roll having a mirror-like thin film on the outer cylinder. The linear pressure between the pair of mirror-like rolls or mirror-like belts is preferably 2 to 100 N/mm, more preferably 10 to 60 N/mm, and further preferably 25 to 45 N/mm. If it is less than 2 N/mm, the mirror surface is not sufficiently transferred, which is not preferable. On the other hand, if it is 100 N/mm or more, the strain remaining in the film is large, and heat shrinkage easily occurs, which is not preferable.

The surface temperature of the pair of mirror-finished rolls or mirror-finished belts is preferably 50°C to 130°C, more preferably 60°C to 100°C. When such a surface temperature is set, the methacrylic resin composition discharged from the extruder can be cooled at a speed faster than natural cooling, and a film having excellent surface smoothness and low haze can be easily produced. The thickness of the unstretched film obtained by extrusion molding is preferably 10 to 300 μm, more preferably 15 to 100 μm. The haze of the film is usually 1.0% or less, preferably 0.5% or less, more preferably 0.3% or less.

The acrylic film of the present invention may be stretched after being formed into a film. The mechanical strength is increased by the stretching treatment, and a film that is hard to crack can be obtained. The stretching method is not particularly limited, and examples thereof include a simultaneous biaxial stretching method, a sequential biaxial stretching method, and a tuber stretching method. From the viewpoint that a film having a high strength can be obtained by uniformly stretching, the lower limit of the temperature during stretching is 10° C. higher than the glass transition temperature of the methacrylic resin composition, and the upper limit of the temperature during stretching is the upper temperature of the methacrylic resin composition. The temperature is 40° C. higher than the glass transition temperature. Stretching is usually performed at 100 to 5000%/min. By performing heat setting after stretching, a film with less heat shrinkage can be obtained. The thickness of the stretched film is preferably 10 to 200 μm.

Further, the acrylic film of the present invention can be subjected to treatments such as easy adhesion treatment, hard coat treatment, and knurling treatment.

Since the acrylic film of the present invention has high transparency and heat resistance, it is suitable for optical applications, and includes a polarizer protective film, a liquid crystal protective plate, a surface material for a portable information terminal, a display window protective film for a portable information terminal, It is particularly suitable for a light guide film, a transparent conductive film having a surface coated with silver nanowires or carbon nanotubes, and a front plate for various displays. In particular, the film of the present invention made of a methacrylic resin composition containing a methacrylic resin and a polycarbonate resin can impart a desired retardation, and thus is suitable for optical applications such as a polarizer protective film and a retardation film. Since the film of the present invention has high transparency and high heat resistance, as an application other than optical applications, an IR cut film, a crime prevention film, a shatterproof film, a decorative film, a metal decorative film, a back sheet of a solar cell, a flexible solar It can be used as a front sheet for batteries, shrink film, and film for in-mold labels.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The measurement of physical properties and the like was carried out by the following methods.

(Polymerization conversion rate)
A gas chromatograph GC-14A manufactured by Shimadzu Corporation was used as a column with GL Sciences Inc. InertCap1 (df=0.4 μm, 0.25 mm ID×60 m) manufactured by InertCap1 is connected, the injection temperature is 180° C., the detector temperature is 180° C., and the column temperature is 60° C. (holding for 5 minutes) to a heating rate The temperature was raised to 200° C. at 10° C./minute, the measurement was performed under the condition of holding for 10 minutes, and the polymerization conversion rate was calculated based on this result.

(Mw, molecular weight distribution)
For the Mw and the molecular weight distribution, a chromatogram was measured by gel permeation chromatography (GPC) under the following conditions, and a value converted into the molecular weight of standard polystyrene was calculated.
GPC device: manufactured by Tosoh Corporation, HLC-8320
Detector: Differential Refractive Index Detector Column: Two TSKgel SuperMultipore HZMM manufactured by Tosoh Corporation and Super HZ4000 connected in series were used.
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 ml/min Column temperature: 40°C
Calibration curve: Created using the data of 10 points of standard polystyrene

(Syndiotacticity (rr) in triplets display)
1H-NMR measurement was performed on the methacrylic resin obtained in each production example. The area (X) of the region of 0.6 to 0.95 ppm and the area (Y) of the region of 0.6 to 1.35 ppm when TMS was set to 0 ppm were measured, and the formula: (X/Y)×100 The value calculated in step 3 was defined as the syndiotacticity (rr) (%) in triplet display.
Apparatus: Nuclear magnetic resonance apparatus (ULTRA SHIELD 400PLUS manufactured by Bruker)
Solvent: Deuterated chloroform Measurement nuclide: 1H
Measurement temperature: Room temperature Accumulation frequency: 64 times

(Glass-transition temperature)
The methacrylic resin obtained in each production example was once heated to 230° C. using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50 (product number)) in accordance with JIS K7121, and then to room temperature. After cooling, the DSC curve was measured under the condition that the temperature was raised from room temperature to 230° C. at 10° C./min. The midpoint glass transition temperature determined from the DSC curve measured during the second temperature increase was taken as the glass transition temperature in the present invention.

(Thickness measurement)
The thickness of the acrylic film was measured with a micro gauge.

(Size of dispersed phase derived from elastomer component (elastomer dispersed phase))
It was measured by phosphotungstic acid staining. Two thin pieces used for measurement were prepared by the following method. A thin piece A was cut out with a microtome in the thickness direction of the film and in the extrusion direction of the film. A thin piece B was obtained by cutting with a microtome in the thickness direction of the film and in the vertical direction of extrusion.
Next, each of the thin pieces A and B was immersed in a phosphotungstic acid solution (PHOSPHOTUNGSTATE ACCIDEM manufactured by TABB Co., Ltd.) 15% by mass, ion-exchanged water 2% by mass, and methanol 83% by mass for 15 minutes for dyeing to obtain a transmission electron microscope (JEOL). (Manufactured by JSM-7600) manufactured at an accelerating voltage of 25 kV and a magnification of 30,000 to 100,000.
In the thin piece A, 100 dispersed phases dyed in the extrusion direction of the film were extracted, the major axis was averaged, and the average value of the major axis (A-Av) was determined.
In the thin piece B, 100 disperse phases dyed in the direction perpendicular to the extrusion of the film were extracted, the major axis was averaged, and the average value of the major axis (B-Av) was determined.
The larger one of the average value of major axis (A-Av) and the average value of major axis (B-Av) was defined as the major axis of the dispersed phase derived from the elastomer component [2].

(Pencil hardness)
The acrylic film was measured according to JIS K 5600-5-4.

(Punchability)
The acrylic film was punched with a punch and visually evaluated as follows.
◯: Good Δ: Slight chipping occurs.
X: Cracks were generated from the punch part.

(Bending whitening)
The acrylic film was bent 180 degrees and evaluated according to the degree of whitening visually.
◯: No whitening.
Δ: Slightly whitened.
X: Whitening is remarkable.
--: Breaks when bent

(chemical resistance)
Using isopropyl alcohol (Wako Pure Chemical Industries, Ltd. reagent grade 1: abbreviated as IPA) and xylene (Wako Pure Chemical Industries reagent grade 1) as chemicals, the method 3 (dropping method) of JISK5600-6-1 was performed. It was evaluated.
◯: No change in appearance.
Δ: Slightly whitened.
X: Marked whitening or dissolution, leaving traces.

Production example 1
[Synthesis of Methacrylic Resin [A-1]]
The inside of the glass-lined 5 m3 reaction vessel equipped with a brine-coolable jacket and a stirrer was replaced with nitrogen. At room temperature, 1600 kg of toluene, 3.19 kg (13.9 mol) of 1,1,4,7,10,10-hexamethyltriethylenetetramine, and 0.45 M isobutylbis(2,6-diamine) were added. 68.6 kg (39.6 mol) of a toluene solution of -t-butyl-4-methylphenoxy)aluminum and a solution of sec-butyllithium having a concentration of 1.3 M (solvent: cyclohexane 95 mass%, n-hexane mass 5%). 7.91 kg (13.2 mol) was charged. While stirring and maintaining the temperature at 20° C., 550 kg of distilled and purified methyl methacrylate was added dropwise over 30 minutes. After completion of dropping, the mixture was stirred at 20° C. for 90 minutes. The color of the solution changed from yellow to colorless. At this point, the polymerization conversion rate of methyl methacrylate was 100%.
The resulting solution was diluted with 1500 kg of toluene. Then, the diluted solution was poured into a large amount of methanol to obtain a precipitate. The obtained precipitate was dried at 80° C. and 140 Pa for 24 hours, and had Mw of 58900, molecular weight distribution of 1.06, syndiotacticity (rr) of 74%, and glass transition temperature of 130° C. A methacrylic resin [A-1] in which the proportion of structural units derived from methyl methacrylate was 100% by mass was obtained.

Production example 2
[Synthesis of Methacrylic Resin [A-2]]
The inside of the glass-lined 5 m3 reaction vessel equipped with a brine-coolable jacket and a stirrer was replaced with nitrogen. At room temperature, 1600 kg of toluene, 2.49 kg (10.8 mol) of 1,1,4,7,10,10-hexamethyltriethylenetetramine, and 0.45 M of isobutylbis(2,6-diamine) were added. 53.5 kg (30.9 mol) of a toluene solution of -t-butyl-4-methylphenoxy)aluminum and a solution of sec-butyllithium having a concentration of 1.3 M (solvent: cyclohexane 95% by mass, n-hexane 5% by mass) 6.17 kg (10.3 mol) was charged. While stirring and maintaining the temperature at 20° C., 550 kg of distilled and purified methyl methacrylate was added dropwise over 30 minutes. After completion of dropping, the mixture was stirred at 20° C. for 90 minutes. The color of the solution changed from yellow to colorless. At this point, the polymerization conversion rate of methyl methacrylate was 100%.
The resulting solution was diluted with 1500 kg of toluene. Then, the diluted solution was poured into a large amount of methanol to obtain a precipitate. The obtained precipitate was dried at 80° C. and 140 Pa for 24 hours, and had Mw of 81400, molecular weight distribution of 1.08, syndiotacticity (rr) of 73%, and glass transition temperature of 131° C. A methacrylic resin [A-2] in which the proportion of structural units derived from methyl methacrylate was 100% by mass was obtained.

Production Example 3
[Synthesis of Methacrylic Resin [A-3]]
The inside of the glass-lined 5 m3 reaction vessel equipped with a brine-coolable jacket and a stirrer was replaced with nitrogen. At room temperature, 1600 kg of toluene, 2.49 kg (10.8 mol) of 1,1,4,7,10,10-hexamethyltriethylenetetramine, and 0.45 M of isobutylbis(2,6-diamine) were added. 53.5 kg (30.9 mol) of a toluene solution of -t-butyl-4-methylphenoxy)aluminum and a solution of sec-butyllithium having a concentration of 1.3 M (solvent: cyclohexane 95% by mass, n-hexane 5% by mass). 6.17 kg (10.3 mol) was charged. While stirring, while maintaining the temperature at -20°C, 550 kg of distilled and purified methyl methacrylate was added dropwise over 30 minutes. After completion of the dropping, the mixture was stirred for 180 minutes while maintaining -20°C. The color of the solution changed from yellow to colorless. At this point, the conversion rate of methyl methacrylate was 100%.
The resulting solution was diluted with 1500 kg of toluene. Then, the diluted solution was poured into a large amount of methanol to obtain a precipitate. The obtained precipitate was dried at 80° C. and 140 Pa for 24 hours, and had a Mw of 96100, a molecular weight distribution of 1.07, a syndiotacticity (rr) of 83%, and a glass transition temperature of 133° C. A methacrylic resin [A-3] was obtained in which the proportion of structural units derived from methyl methacrylate was 100% by mass.

Production Example 4
[Synthesis of Methacrylic Resin [A-4]]
The inside of the autoclave equipped with a stirrer and a sampling tube was replaced with nitrogen. To this, 100 parts by mass of purified methyl methacrylate, 2,2′-azobis(2-methylpropionitrile (hydrogen abstraction ability: 1%, 1 hour half-life temperature: 83° C.) 0.0052 parts by mass, and 0.28 parts by mass of n-octyl mercaptan was added and stirred to obtain a raw material liquid, and nitrogen was fed into the raw material liquid to remove dissolved oxygen in the raw material liquid.
The raw material liquid was charged to a tank reactor connected to the autoclave by a pipe to a volume of 2/3. The temperature was maintained at 140° C. to start the polymerization reaction in batch mode first. When the polymerization conversion rate reached 55% by mass, the raw material liquid was supplied from the autoclave to the tank reactor at a flow rate such that the average residence time was 150 minutes, and the reaction liquid was supplied at a flow rate corresponding to the supply flow rate of the raw material liquid. It was withdrawn from the tank reactor, the temperature was maintained at 140° C., and the polymerization reaction was switched to the continuous flow system. After the switching, the polymerization conversion rate in the steady state was 55% by mass.

The reaction liquid extracted from the tank-type reactor in the steady state was supplied to a multi-tube heat exchanger having an internal temperature of 230° C. at a flow rate to give an average residence time of 2 minutes and heated. Next, the heated reaction liquid was introduced into a flash evaporator to remove a volatile component containing an unreacted monomer as a main component to obtain a molten resin. The molten resin from which the volatile components have been removed is supplied to a twin-screw extruder having an internal temperature of 260° C., discharged in a strand shape, cut with a pelletizer, and pelletized to have a Mw of 82000 and a molecular weight distribution of 1.85. A methacrylic resin [A-4] having a syndiotacticity (rr) of 52%, a glass transition temperature of 120° C., and a content of structural units derived from methyl methacrylate of 100% by mass was obtained.

The obtained methacrylic resins [A-1] to [A-4] are shown below.

Production Example 5
[Synthesis of Block Copolymer (B-1)]
A glass-lined 3 m3 reaction vessel equipped with a jacket and a stirrer, which was degassed and purged with nitrogen and was cooled with brine, was dried at room temperature with 735 kg of dry toluene, 0.4 kg of hexamethyltriethylenetetramine, and isobutylbis(2,6). 39.4 kg of a toluene solution containing 20 mol of (di-t-butyl-4-methylphenoxy)aluminum was added, and further 1.17 mol of sec-butyllithium was added. To this, 35.0 kg of methyl methacrylate was added and reacted at room temperature for 1 hour. The polymer contained in the reaction solution was sampled and the weight average molecular weight (hereinafter referred to as Mw(b1-1)) was measured to be 40,000. Such a methyl methacrylate polymer is further subjected to block copolymerization of an acrylic acid ester to give a methyl methacrylate polymer block (b1) (hereinafter, referred to as "methyl methacrylate polymer block (b1-1)". It is called).

Next, while maintaining the reaction liquid at -25°C, 35 kg of n-butyl acrylate was added dropwise over 0.5 hour. Immediately after the dropping, the polymer contained in the reaction solution was sampled and the weight average molecular weight was measured and found to be 80,000. Since the weight average molecular weight of the methyl methacrylate polymer block (b1-1) was 40,000, the weight average molecular weight (Mw(b2)) of the acrylic acid ester polymer block (b2) composed of n-butyl acrylate. Was determined to be 40,000.

Subsequently, 35.0 kg of methyl methacrylate was added, the reaction solution was returned to room temperature, and stirred for 8 hours to obtain a second methacrylate ester polymer block (b1) (hereinafter, referred to as "methyl methacrylate polymer block (b1 -2)"). After that, 4 kg of methanol was added to the reaction solution to stop the polymerization, and then the reaction solution was poured into a large amount of methanol, and the block copolymer (B) that was a triblock copolymer (hereinafter, referred to as "block copolymer ( B-1)") was precipitated, filtered, and dried at 80° C. and 1 torr (about 133 Pa) for 12 hours to be isolated. The weight average molecular weight Mw(B) of the obtained block copolymer (B-1) was 120,000. Since the weight average molecular weight of the diblock copolymer was 80,000, the weight average molecular weight (referred to as Mw(b1-2)) of the methyl methacrylate polymer block (b1-2) was 40,000. Decided. Since the weight average molecular weight Mw(b1-1) of the methyl methacrylate polymer block (b1-1) and the weight average molecular weight Mw(b1-2) of the methyl methacrylate polymer block (b1-2) are both 40,000. , Mw(b1) was 40,000. The content of acrylic acid ester in this block copolymer is 33%.

Production Example 6
[Synthesis of Block Copolymer (B-2)]
A glass-lined 3 m3 reaction vessel equipped with a jacket and a stirrer, the inside of which was deaerated and purged with nitrogen, and which was cooled with brine, was dried at room temperature with 735 kg of dry toluene, 0.4 kg of hexamethyltriethylenetetramine, and isobutylbis(2,6- 39.4 kg of a toluene solution containing 20 mol of di-t-butyl-4-methylphenoxy)aluminum was added, and further 1.17 mol of sec-butyllithium was added. To this, 35.0 kg of methyl methacrylate was added and reacted at room temperature for 1 hour. The polymer contained in the reaction solution was sampled and the weight average molecular weight (hereinafter referred to as Mw(b1-1)) was measured to be 40,000. Such a methyl methacrylate polymer is further block-copolymerized with an acrylic acid ester to give a methyl methacrylate polymer block (b1) (hereinafter, referred to as "methyl methacrylate polymer block (b1-1)". It is called).

Then, while maintaining the reaction liquid at -25°C, a mixed liquid of 24.5 kg of n-butyl acrylate and 10.5 kg of benzyl acrylate was added dropwise over 0.5 hours. Immediately after the dropping, the polymer contained in the reaction solution was sampled and the weight average molecular weight was measured and found to be 80,000. Since the weight average molecular weight of the methyl methacrylate polymer block (b1-1) was 40,000, the weight of the acrylate polymer block (b2) composed of a copolymer of n-butyl acrylate and benzyl acrylate. The average molecular weight (Mw(b2)) was determined to be 40,000. The content of acrylic ester in this block copolymer is 50%.

Production Example 7
[Synthesis of core-shell type graft copolymer (B-3)]
(1) In a reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction pipe, a monomer introduction pipe and a reflux condenser, 1050 parts by mass of ion-exchanged water and 0.6 parts by mass of sodium polyoxyethylene tridecyl ether acetate. Then, 0.7 part by mass of sodium carbonate was charged, and the inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set to 80°C. 0.25 parts by mass of potassium persulfate was added thereto and stirred for 5 minutes. To this, 245 parts by mass of a monomer mixture consisting of 95.4% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.2% by mass of allyl methacrylate was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more.
(2) Next, 0.32 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 315 parts by mass of a monomer mixture consisting of 80.5% by mass of butyl acrylate, 17.5% by mass of styrene and 2% by mass of allyl methacrylate were continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more. (3) Next, 0.14 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 140 parts by mass of a monomer mixture consisting of 95.2% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.4% by mass of n-octyl mercaptan was continuously added dropwise over 30 minutes. After the completion of the dropping, the polymerization reaction was further performed for 60 minutes so that the polymerization conversion rate was 98% or more. By the above operation, a latex containing the crosslinked rubber particles (A1) was obtained. The latex containing the crosslinked rubber particles (A1) was frozen and coagulated. Then, it was washed with water and dried to obtain a core-shell type graft copolymer. The average particle size of the graft copolymer was 0.09 μm. The content of acrylic ester in this core-shell type graft copolymer is 39%.

Production Example 8
[Synthesis of core-shell type graft copolymer (B-4)]
(1) In a reactor equipped with a stirrer, a thermometer, a nitrogen gas introducing pipe, a monomer introducing pipe and a reflux condenser, 1050 parts by mass of ion-exchanged water and 0.1 parts by mass of sodium polyoxyethylene tridecyl ether acetate. Then, 0.7 part by mass of sodium carbonate was charged, and the inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set to 80°C. 0.25 parts by mass of potassium persulfate was added thereto and stirred for 5 minutes. To this, 245 parts by mass of a monomer mixture consisting of 95.4% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.2% by mass of allyl methacrylate was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more.
(2) Next, 0.32 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 315 parts by mass of a monomer mixture consisting of 80.5% by mass of butyl acrylate, 17.5% by mass of styrene and 2% by mass of allyl methacrylate were continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more.
(3) Next, 0.14 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 140 parts by mass of a monomer mixture consisting of 95.2% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.4% by mass of n-octyl mercaptan was continuously added dropwise over 30 minutes. After the completion of the dropping, the polymerization reaction was further performed for 60 minutes so that the polymerization conversion rate was 98% or more. By the above operation, a latex containing the crosslinked rubber particles (A1) was obtained. The latex containing the crosslinked rubber particles (A1) was frozen and coagulated. Then, it was washed with water and dried to obtain a core-shell type graft copolymer. The average particle size of the graft copolymer was 0.35 μm. The content of acrylic ester in this core-shell type graft copolymer is 39%.

[Synthesis of core-shell type graft copolymer (B-5)]
(1) In a reactor equipped with a stirrer, a thermometer, a nitrogen gas introducing pipe, a monomer introducing pipe and a reflux condenser, 1050 parts by mass of ion-exchanged water and 1.0 part by mass of sodium polyoxyethylene tridecyl ether acetate. Then, 0.7 part by mass of sodium carbonate was charged, and the inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set to 80°C. 0.25 parts by mass of potassium persulfate was added thereto and stirred for 5 minutes. To this, 445 parts by mass of a monomer mixture consisting of 95.4% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.2% by mass of allyl methacrylate was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more.
(2) Next, 0.32 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 115 parts by mass of a monomer mixture consisting of 80.5% by mass of butyl acrylate, 17.5% by mass of styrene and 2% by mass of allyl methacrylate were continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 30 minutes so that the conversion rate of the polymerization was 98% or more.
(3) Next, 0.14 parts by mass of potassium persulfate was placed in the reactor and stirred for 5 minutes. Thereafter, 140 parts by mass of a monomer mixture consisting of 95.2% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.4% by mass of n-octyl mercaptan was continuously added dropwise over 30 minutes. After the completion of the dropping, the polymerization reaction was further performed for 60 minutes so that the polymerization conversion rate was 98% or more. By the above operation, a latex containing the crosslinked rubber particles (A1) was obtained. The latex containing the crosslinked rubber particles (A1) was frozen and coagulated. Then, it was washed with water and dried to obtain a core-shell type graft copolymer. The average particle size of the graft copolymer was 0.09 μm. The content of acrylic ester in this core-shell type graft copolymer is 17%.

The obtained elastomer components (B-1) to (B-5) are shown below.

The following were used as ultraviolet absorbers.
D-1: BASF UV absorber TINUVIN460
D-2: BASF UV absorber TINUVIN479

<Example 1>
85 parts by weight of methacrylic resin [A-1], 15 parts by weight of block copolymer (B-1) and 1 part by weight of ultraviolet absorber [D-1] are mixed in a tumbler, and a twin-screw kneading extruder (Toshiba Machinery Co., Ltd. Extruded methacrylic resin composition at a set temperature of 250° C. by TEM-41SS manufactured by the company.
The methacrylic composition was melt-extruded at a cylinder temperature of 250° C. and a die temperature of 260° C. with a 65φ mm single-screw extruder equipped with a T-die, and sandwiched between a metal elastic roll set at 80° C. and a metal rigid roll set at 80° C. Then, a film having a thickness of 40 μm was produced. The evaluation results are shown in Table 3.

<Examples 2 to 6>
A methacrylic resin composition having the composition shown in Table 3 was produced in the same manner as in Example 1, and films having respective thicknesses were obtained under the same temperature conditions as in Example 1. The results are summarized in Table 3.

<Comparative Examples 1 to 6>
A methacrylic resin composition having the formulation shown in Table 4 was produced in the same manner as in Example 1, and the same apparatus as in Example 1 was used to obtain films having respective thicknesses. The results are shown in Table 4.

From the above results, a film out of the range defined by the acrylic film of the present invention has poor pencil hardness and chemical resistance (Comparative Example 1), punching property and whitening by bending (Comparative Example 2,). 3 and 6), the glass transition temperature is lowered, and the chemical resistance to xylene is lowered (Comparative Examples 4 and 5).

<Examples 7 to 11>
A methacrylic resin composition having the formulation shown in Table 5 was produced in the same manner as in Example 1, and an 80 μm film was produced by the same production method as in Example 1. After that, the film was heated at 140° C. and biaxially stretched in a tenter system so that the length and width were doubled to obtain a film of 20 μm. The evaluation results of the obtained film are shown in Table 5.

From Examples 7 to 11, in the case of the biaxially stretched film, the punchability is good even if the blending amount of the elastomer component is small, and the pencil hardness is high, so that the rigidity is high and the surface hardness can be increased. I understand.

<Example 12>
6 parts by weight of polycarbonate Iupilon HL-8000 manufactured by Mitsubishi Engineering Plastics was added to 100 parts by weight of the methacrylic resin [A-1] and the block copolymer (B-3) having the same composition as in Example 7. Then, the mixture was melt-kneaded to produce a methacrylic resin composition [C-1], and an 80 μm film was produced in the same manner as in Example 7. After that, the film was heated at 140° C. and biaxially stretched by a tenter system so that the length and width of the film were doubled to prepare a film of 20 μm.
As a result of evaluation of the obtained film, the size of the elastomer dispersed phase was 250 nm, the pencil hardness was F to HB, the punchability was ○, the whitening by bending was ○, and the chemical resistance was ○ for both IPA and xylene.

<Example 13>
Instead of polycarbonate Iupilon HL-8000 manufactured by Mitsubishi Engineering Plastics, SDPOLYCATR-2000 manufactured by Sumika Styron Polycarbonate Co., Ltd. was used as the polycarbonate, and methacrylic acid was obtained in the same manner as in Example 12 except that the addition amount was 4 parts by weight. A resin composition [C-2] was produced, and a 20 μm film was produced in the same manner as in Example 12. As a result of evaluation of the obtained film, the size of the elastomer dispersed phase was 250 nm, the pencil hardness was F to HB, the punchability was ○, the whitening by bending was ○, and the chemical resistance was ○ for both IPA and xylene.

From the above results, the mass ratio of the methacrylic resin [1] having a syndiotacticity (rr) represented by triplets of 65% or more and the elastomer component [2] of 60/99 to 40/1 (methacrylic resin [ 1]/Elastomer component [2]) may be blended with a polycarbonate resin to obtain a film having excellent glass transition temperature pencil hardness, punching property, bending whitening and chemical resistance. Recognize.

Claims (10)

A methacrylic resin having a methacrylic resin [1] having a syndiotacticity (rr) of 65% or more in triplets and an elastomer component [2] containing 30% by mass or more of a structural unit derived from an acrylate ester is a methacrylic resin. An acrylic film comprising a methacrylic resin composition containing a mass ratio of [1]/elastomer component [2] of 60/40 to 99/1,
The methacrylic resin [1] has a molecular weight distribution of 1.5 or less,
Contains a core-shell type graft copolymer as the elastomer component [2],
An acrylic film, wherein a major axis of a dispersed phase derived from the elastomer component [2] is 10 to 300 nm when a thin piece of the acrylic film is dyed with phosphotungstic acid. The acrylic film according to claim 1, wherein a mass ratio of the methacrylic resin [1]/elastomer component [2] is 80/20 to 99/1. As the elastomer component [2], a block copolymer composed of a combination of a polymer (b1) having a structural unit containing methacrylic acid ester as a main component and a polymer (b2) having a structural unit containing acrylic acid ester. The acrylic film according to claim 1 or 2, which contains a united body. The acrylic film according to claim 1, wherein the methacrylic resin composition further contains an ultraviolet absorber. The methacrylic resin composition further contains 1 to 10 parts by mass of a polycarbonate resin based on 100 parts by mass of the total amount of the methacrylic resin [1] and the elastomer component [2]. The acrylic film described in one. A laminated film using the acrylic film according to claim 1. A polarizer protective film comprising the acrylic film according to claim 1. A methacrylic resin having a methacrylic resin [1] having a syndiotacticity (rr) of 65% or more in triplets and an elastomer component [2] containing 30% by mass or more of a structural unit derived from an acrylate ester is a methacrylic resin. A method for producing an acrylic film, comprising melt-kneading a [1]/elastomer component [2] at a mass ratio of 60/40 to 99/1 to obtain a methacrylic resin composition, and molding the methacrylic resin composition. There
The methacrylic resin [1] has a molecular weight distribution of 1.5 or less,
Contains a core-shell type graft copolymer as the elastomer component [2],
A method for producing an acrylic film, wherein a major axis of a dispersed phase derived from the elastomer component [2] is 10 to 300 nm when a thin piece of the acrylic film is dyed with phosphotungstic acid. The method for producing an acrylic film according to claim 8, wherein the acrylic film is further stretched. The method for producing an acrylic film according to claim 8, further comprising melt-kneading a polycarbonate resin to obtain the methacrylic resin composition.