JP6783112B2 - Acrylic resin film and its manufacturing method - Google Patents

Description

The present invention relates to an acrylic resin film having good surface smoothness, low haze, less discoloration, and less fish eye defects, and a method for producing the same.

Acrylic resin films are classified into display materials such as signboards and flat panel displays, and decorative films because they have features such as high transparency, high surface hardness, excellent weather resistance, and easy molding. It is used in various applications such as interior and exterior materials for vehicles, interior and exterior materials for building materials, and interior members. In particular, it is used as a skin material for various members because of its excellent surface properties. However, acrylic resin films are very brittle, and are used for processing when transporting films during film formation, when passing through accumulators, when trim cutting, when winding, and when cutting films after winding. Problems such as cracking may occur when the film is transported, when secondary processing is performed by thermoforming, when trimming to remove unnecessary parts after thermoforming, or when the film is bonded to another base film. there were.

Therefore, in order to improve the brittleness of the film made of only the acrylic resin, a method of alloying and blending various materials has been proposed. Patent Document 1 proposes an acrylic resin film in which core-shell type particles are blended. Further, Patent Document 2 proposes an acrylic resin film in which a polyvinyl acetal resin is alloyed. In Patent Document 3, a block copolymer having at least one structure in which a highly syndiotactic polymethacrylic acid alkyl ester block is bonded to both ends of a thermoplastic resin and a polyacrylic acid alkyl ester block in the molecule. A polymer composition containing the above in a specific ratio has been proposed. Further, in Patent Document 4, a resin using a block copolymer having an acrylic acid ester polymer block containing a specific amount of a structural unit derived from an acrylic acid alkyl ester and a structure derived from a (meth) acrylic aromatic ester, respectively. The composition is disclosed. Further, Patent Document 5 discloses an acrylic resin composition in which 0.3 to 3 parts by mass of a polymer processing aid is blended with 100 parts by mass of an acrylic block copolymer.

By the way, in recent years, acrylic resin films have been increasingly used as protective films for polarizers used in liquid crystal display devices and organic EL display devices, or retardation films. When used in these optical applications, higher quality is required, especially with regard to fish eye defects. Patent Documents 6 and 7 introduce acrylic films having few defects of foreign substances, but there are problems such as insufficient tear strength because they do not contain a modifier such as rubber and are stretched. Had. Further, the reduction of fish eye defects has been a requirement that has been sought from the advantage of improving the product yield even when used for interior materials and exterior materials for vehicles.

Special Publication No. 56-27378 Japanese Unexamined Patent Publication No. 2013-23599 Special Fair 10-168271 International Publication No. 2014/073216 Japanese Unexamined Patent Publication No. 2013-43964 Japanese Unexamined Patent Publication No. 2012-82358 Japanese Unexamined Patent Publication No. 2014-95926

According to the above Patent Documents 1 to 5, various properties such as brittleness of the acrylic resin can be improved. Further, according to Patent Documents 6 to 7, a film having few defects of foreign matter can be produced. However, in recent years, the required performance of a film has become higher, and a film having high transparency and surface hardness and having a plurality of characteristics in a well-balanced manner is required. Specifically, there is a demand for a film having high surface smoothness, transparency, impact resistance, and better quality (less fish eyes).

The present invention has been made in view of the above background, and an object thereof is an acrylic system having high transparency, surface smoothness, surface hardness, excellent impact resistance, and few fish eye defects. The present invention provides a resin film and a method for producing the same.

As a result of diligent studies, the present inventors have completed an invention including the following aspects.

[1]; A methacrylic resin (A) having a structural unit derived from methyl methacrylate in an amount of 80% by mass or more and having a melt viscosity (η (A)) of 1500 to 3500 Pa · s at 220 ° C. and a shear rate of 122 / sec. ) Is an acrylic resin film containing 70% by mass or more.
Acrylic resin film with surface roughness of 5 nm or less, haze of 0.7% or less, yellowness of 1.0 or less, and fish eye defects of 0.03 mm ² or more and 0.2 pieces / m ² or less. ..
[2]; The acrylic resin film according to [1], wherein the pencil hardness on at least one surface is HB or harder than that.
[3]; The acrylic resin film according to [1] or [2], which has an impact resistance of 40 mJ or more.
[4]; The acrylic resin composition is characterized by containing 0.1 to 3 parts by mass of the polymer processing aid (C) with respect to 100 parts by mass of the acrylic resin composition [1]. The acrylic resin film according to any one of [3].
[5]; any of [1] to [4], wherein the polymer processing aid (C) contains 60 to 90% by mass of methyl methacrylate and 10 to 40% by mass of alkyl acrylate. Acrylic resin film described in Crab.
[6]; The acrylic resin composition contains a block copolymer (B) in which a methacrylic acid ester polymer block (b2) is bonded to an acrylic acid ester polymer block (b1), and is a block copolymer (B). The melt viscosity (η (B)) of B) at 220 ° C. and a shear rate of 122 / sec is 75 to 1500 Pa · s, and the ratio of the melt viscosity (η (A)) to the melt viscosity (η (B)). The acrylic resin film according to any one of [1] to [5], wherein the value of (η (A) / η (B)) is 1 to 20.
[7]; The acrylic resin composition contains 70 to 99 parts by mass of the methacrylic resin (A) and the block copolymer (a block copolymer (A) with respect to 100 parts by mass of the total of the methacrylic resin (A) and the block copolymer (B). B) The acrylic resin film according to [6], which contains 1 to 30 parts by mass.
[8]; The block copolymer (B) is characterized by containing 30 to 60% by mass of the acrylic acid ester polymer block (b1) and 40 to 70% by mass of the methacrylic acid ester polymer block (b2). The acrylic resin film according to [6] or [7].
[9]; The acrylic resin film according to any one of [6] to [8], wherein the block copolymer (B) is a triblock copolymer.
[10]; In the triblock copolymer (B), the mass ratios of the two methacrylic acid ester polymer blocks (b2) bonded to both ends of the acrylic acid ester polymer block (b1) are different from each other. And
In the two methacrylic ester polymer blocks (b2), the methacrylic acid having a larger mass ratio to the mass ratio (n (L)) of the methacrylic ester polymer block (b2 (L)) having a smaller mass ratio. [9], wherein the value of the mass ratio (n (H)) ratio (n (H) / n (L)) of the ester polymer block (b2 (H)) is 1.5 or more. The acrylic resin film described.
[11]; The acrylic resin composition contains 0.1 to 3 parts by mass of the ultraviolet absorber (D) with respect to 100 parts by mass of the total of the methacrylic resin (A) and the block copolymer (B). The acrylic resin film according to any one of [1] to [10], which is characterized by containing.
[12]; A stretched film made of the acrylic resin film according to any one of [1] to [11].
[13]; An optical film comprising the acrylic resin film according to any one of [1] to [11] or the stretched film according to [12].
[14]; A polarizing element protective film, which comprises using the acrylic resin film according to any one of [1] to [11] or the stretched film according to [12].
[15]; A polarizing plate containing at least one polarizing element protective film according to [14].
[16]; It is characterized in that the surface of either the acrylic resin film according to any one of [1] to [11] or the stretched film according to [12] is decorated. Decorative film.
[17]; A method for producing the acrylic resin film according to any one of [1] to [11] by an extruder equipped with a T-die, the extruder including a vent, a gear pump, and a polymer filter. A method for producing an acrylic resin film, which comprises controlling the temperature of a vent, a gear pump, a polymer filter, and a T-die in a range of 230 to 290 ° C.

According to the present invention, it is possible to provide an acrylic resin film having high transparency, surface smoothness, surface hardness, excellent impact resistance, and few fish eye defects, and a method for producing the same.

Hereinafter, an example of an embodiment to which the present invention is applied will be described. The numerical values specified in the present specification indicate values obtained when measured by the method described in Examples described later. Further, the numerical values "A to B" specified in the present specification indicate a range that is larger than the numerical values A and A and satisfies the values smaller than the numerical values B and B. Further, the "film" of the present invention is not limited to the thickness and the like, and may be provided in a roll shape, and includes a "sheet" defined in JIS.

The resin used for the acrylic resin film of the present invention has a structural unit derived from methyl methacrylate in an amount of 80% by mass or more, and has a melt viscosity (η (A)) of 1500 to 3500 Pa at 220 ° C. and a shear rate of 122 / sec. -The methacrylic resin (A) which is s.

The ratio of the structural unit derived from methyl methacrylate in the methacrylic resin (A) needs to be 80% by mass or more, and from the viewpoint of heat resistance, it is preferably 90% by mass or more, more preferably 95% by mass or more. That is, the proportion of the structural unit derived from the monomer other than methyl methacrylate is 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and all the monomers are methyl methacrylate. Also includes the configuration that is.

Examples of the monomer other than methyl methacrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, and tert-acrylate. Butyl, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethyl hexyl acrylate, pentadecyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-ethyl acrylate Acrylic acid esters such as hydroxyethyl, 2-ethoxyethyl acrylate, glycidyl acrylate, allyl acrylate, cyclohexyl acrylate, norbornyl acrylate, isobornyl acrylate; ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate , N-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, Dodecyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-ethoxyethyl methacrylate, glycidyl methacrylate, allyl methacrylate, cyclohexyl methacrylate, norbornyl methacrylate, methacrylic Methacrylic acid esters other than methyl methacrylate such as isobornyl acid; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, maleic acid and itaconic acid; such as ethylene, propylene, 1-butene, isobutylene and 1-octene. Olefins; conjugated diene such as butadiene, isoprene, milsen; aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; acrylamide, methacrylicamide, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl Examples thereof include pyridine, vinyl ketone, vinyl chloride, vinylidene chloride and vinylidene fluoride.

There is no particular limitation on the stereoregularity of the methacrylic resin (A), and for example, those having stereoregularity such as isotactic, heterotactic, and syndiotactic may be used. However, from the viewpoint of heat resistance, it is preferable to use a methacrylic resin (A) having many syndiotactic structures.

The melt viscosity (η (A)) of the methacrylic resin (A) at 220 ° C. and a shear rate of 122 / sec is in the range of 1500 to 3500 Pa · s. The melt viscosity (η (A)) is more preferably 1800 Pa · s or more, and particularly preferably 2000 Pa · s or more. Further, it is more preferably 3300 Pa · s or less, and particularly preferably 3100 Pa · s or less. By setting the range from 1500 to 3500 Pa · s, the impact resistance and toughness of the molded product or film of the obtained resin composition can be kept good.

Regarding the molecular weight distribution of the methacrylic resin (A), the ratio (Mw / Mn) of the weight average molecular weight Mw to the number average molecular weight Mn as measured by GPC is preferably 1.05 to 3. More preferably, it is 1.3 to 2.5. When the molecular weight distribution is less than 1.05, molding processability becomes difficult when used alone, and when the molecular weight distribution is 3 or more, physical properties deteriorate.

The methacrylic resin (A) is produced by polymerizing one or more kinds of monomers containing 80% by mass or more of methyl methacrylate. At this time, the degree of polymerization of the methacrylic resin (A) can be adjusted by the amount of the initiator and the chain transfer agent.

A commercially available product may be used for the methacrylic resin (A) of the present invention. Examples of such commercially available methacryl resins include "Parapet H1000B" (MFR: 22 g / 10 minutes (230 ° C., 37.3 N)) and "Parapet GF" (MFR: 15 g / 10 minutes (230 ° C., 37.3 N)). )), "Parapet EH" (MFR: 1.3 g / 10 minutes (230 ° C, 37.3N)), "Parapet HRL" (MFR: 2.0 g / 10 minutes (230 ° C, 37.3N)), " "Parapet HRS" (MFR: 2.4 g / 10 minutes (230 ° C, 37.3N)) and "Parapet G" (MFR: 8.0 g / 10 minutes (230 ° C, 37.3N)) [Both trade names, Made by Kuraray] and so on.

The block copolymer (B) is a resin in which a methacrylic acid ester polymer block (b2) is bonded to an acrylic acid ester polymer block (b1). There is no particular limitation on the bonding state between (b1) and (b2), and the diblock copolymer represented by (b1)-(b2), (b1)-(b2)-(b1), (b2)-. A triblock polymer represented by (b1)-(b2), (b1)-((b2)-(b1)) n, (b1)-((b2)-(b1)) n- (b2) , (B2)-((b1)-(b2)) n-represented multi-block copolymer, ((b1)-(b2)) n-X, ((b2)-(b1)) n-X Any star block copolymer represented by (X is a coupling residue) may be used. From the viewpoint of adhesiveness at high temperature and the resulting adhesion to the molding roll, cost, and physical properties such as impact resistance, the triblocks (b2)-(b1)-(b2) It is preferably a copolymer. In this case, the two methacrylic acid ester polymer blocks (b2) bonded to both ends of the acrylic acid ester polymer block (b1) are composed of the types of monomers, the ratio of structural units derived from the methacrylic acid ester, and The weight average molecular weight and the stereoregularity may be the same or different independently. Further, other polymer blocks may be contained as long as the gist of the present invention is not deviated.

When the block copolymer (B) is a triblock copolymer of (b2)-(b1)-(b2), the weight of two methacrylic acid esters bonded to both ends of the acrylic acid ester polymer block (b1). The mass ratios of the coalesced blocks (b2) may be substantially the same, but are preferably different values from the viewpoint of improving the fluidity at the time of melting and facilitating uniform dispersion. That is, when the block copolymer (B) is 100% by mass, the mass ratios of the methacrylic acid ester polymer blocks (b2) bonded to both ends of the acrylic acid ester polymer block (b1) are different from each other. It is preferable to use one. By improving the fluidity at the time of melting, a high-quality film or molded product can be obtained, and by further uniformly dispersing, fish eyes are reduced and the balance between elastic modulus and impact resistance is improved.

When the mass ratios of the methacrylic ester polymer blocks (b2) are different from each other, the mass ratio of the methacrylic ester polymer block (b2 (L)) having a smaller mass ratio to the mass ratio (n (L)) of the methacrylic ester polymer block (b2) is larger. The value of the mass ratio (n (H)) ratio (n (H) / n (L)) of the methacrylic ester polymer block (b2 (H)) is more preferably 1.5 or more, and further. It is preferably 1.8 or more, and the upper limit thereof is preferably 4 or less, and more preferably 3 or less. By improving the fluidity at the time of melting, a high-quality film or molded product can be obtained.

The acrylic acid ester polymer block (b1) constituting the block copolymer (B) has a structural unit derived from the acrylic acid ester as a main structural unit. The proportion of the structural unit derived from the acrylic acid ester in the acrylic acid ester polymer block (b1) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass. % Or more, and a composition of 100% by mass is also included.

Examples of such acrylic acid esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, and acrylic. Amil acid, isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, acrylate Examples thereof include 2-hydroxyethyl, 2-methoxyethyl acrylate, glycidyl acrylate, and allyl acrylate. Acrylic acid ester polymer block (b1) can be formed by polymerizing one of these acrylic acid esters alone or in combination of two or more. Of these, those polymerized with n-butyl acrylate alone are preferable from the viewpoint of cost and low temperature characteristics.

The acrylic ester polymer block (b1) may contain structural units derived from a monomer other than the acrylic ester, as long as it does not interfere with the object and effect of the present invention. The proportion of the structural unit derived from the monomer other than the acrylic acid ester contained in the acrylic acid ester polymer block (b1) is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass. Hereinafter, it is particularly preferably 10% by mass or less, and includes the case where all the structural units are monomers derived from acrylic acid ester.

Examples of the monomer other than the acrylic acid ester include methacrylic acid ester, unsaturated carboxylic acid, aromatic vinyl compound, olefin, conjugated diene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, vinylpyridine, vinyl ketone, and the like. Examples thereof include vinyl chloride, vinylidene chloride and vinylidene fluoride. When a monomer other than the acrylic acid ester is used, the acrylic acid ester polymer block (b1) can be obtained by copolymerizing one type alone or two or more types together with the above-mentioned acrylic acid ester. Can be formed.

The methacrylic acid ester polymer block (b2) has a structural unit derived from a methacrylic acid ester as a main structural unit. The proportion of the structural unit derived from the methacrylic acid ester in the methacrylic acid ester polymer block (b2) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 98% by mass. % Or more, including the case where all structural units are monomers derived from methacrylic acid ester.

Examples of such methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, and methacrylic acid. Amil 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 Examples thereof include 2-hydroxyethyl, 2-methoxyethyl methacrylate, glycidyl methacrylate, and allyl methacrylate. Among these, from the viewpoint of improving transparency and heat resistance, methacrylic acids 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. A methacrylic acid ester polymer block (b2) can be formed by polymerizing one of these methacrylic acid esters alone or in combination of two or more.

The methacrylic acid ester polymer block (b2) may contain a structural unit derived from a monomer other than the methacrylic acid ester as long as it does not interfere with the object and effect of the present invention. The proportion of the structural unit derived from the monomer other than the methacrylate ester contained in the methacrylic ester polymer block (b2) is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass. Hereinafter, it is particularly preferably 2% by mass or less.

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

The ratio of the methacrylic acid ester polymer block (b2) in the block copolymer (B) is transparent with respect to 100% of the total of the acrylic acid ester polymer block (b1) and the methacrylic acid ester polymer block (b2). From the viewpoints of surface hardness, moldability, surface smoothness, and impact resistance, it is preferably 40% by mass or more, more preferably 43% by mass or more, and further preferably 47% by mass or more. .. Further, it is preferably 70% by mass or less, more preferably 65% by mass or less, and further preferably 60% by mass or less.

Regarding the stereoregularity of the methacrylic acid ester polymer block (b2), it is preferable that the syndiotacticity (rr) of the triplet display is 60% or more from the viewpoint of enhancing heat resistance. By setting the syndiotacticity to 60% or more, the glass transition temperature is raised, and the resin composition of the present invention exhibits excellent heat resistance. It is more preferably 65% or more, further preferably 70% or more, and most preferably 75% or more.

The melt viscosity (η (B)) of the block copolymer (B) at 220 ° C. and a shear rate of 122 / sec is preferably in the range of 75 to 1500 Pa · s. The melt viscosity (η (B)) is more preferably 150 Pa · s or more, and particularly preferably 300 Pa · s or more. Further, it is more preferably 1000 Pa · s or less, and particularly preferably 700 Pa · s or less. By setting the range to 75 to 1500 Pa · s, good melt tension can be maintained in melt extrusion molding, and a good plate-shaped molded product can be easily obtained. In addition, mechanical properties such as breaking strength of the obtained plate-shaped molded product can be kept good. Further, it is possible to effectively suppress the generation of fine grain-like unevenness and lumps caused by unmelted matter (high molecular weight body) on the surface of the plate-shaped molded product obtained by melt extrusion molding, and obtain a good film. it can.

Further, the value of the ratio (η (A) / η (B)) of the melt viscosity (η (A)) to the melt viscosity (η (B)) is preferably 1 to 20, more preferably 5 to 10. , More preferably 6-8. When the values of η (A) / η (B) are 1 to 20, good dispersibility can be ensured, and the film has excellent mechanical properties and optical properties.

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 end of the molecular chain, if necessary.

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 living-polymerizing the monomers constituting each polymer block is generally used. Examples of such a living polymerization method include a method of anion polymerization using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid such as an alkali metal or an alkaline earth metal salt, and an organic alkali metal compound. A method of anion polymerization using an organic aluminum compound as a polymerization initiator, a method of polymerizing using an organic rare earth metal complex as a polymerization initiator, and a method of polymerizing using an α-halogen ester compound as an initiator in the presence of a copper compound. Examples thereof include a method of radical polymerization. Further, a method of polymerizing the monomers constituting each block using a polyvalent radical polymerization initiator or a polyvalent radical chain transfer agent to produce a mixture containing the block copolymer (B) used in the present invention. Can also be mentioned. Among these methods, in particular, since the block copolymer (B) can be obtained with high purity, the molecular weight and composition ratio can be easily controlled, and it is economical, an organic alkali metal compound is used as a polymerization initiator. A method of anionic polymerization in the presence of an organoaluminum compound is preferred.

The composition ratio of the methacrylic resin (A) and the block copolymer (B) is such that the methacrylic resin (A) and the block copolymer (B) are formed from the viewpoint of forming a film having improved brittleness while maintaining a high surface hardness. It is preferable that the methacrylic resin (A) is 70 to 99 parts by mass, the block copolymer (B) is 1 to 30 parts by mass, and the methacrylic resin (A) is 80 to 92 parts by mass per 100 parts by mass in total. , It is more preferable that the block copolymer (B) is 8 to 20 parts by mass.

The acrylic resin composition used in the present invention contains various additives, for example, a polymer processing aid (C), an ultraviolet absorber (D), and oxidation, as required, as long as the effects of the present invention are not impaired. Inhibitors, heat stabilizers, lubricants, antistatic agents, colorants, impact-resistant aids and the like may be added. From the viewpoint of the mechanical properties and surface hardness of the film of the present invention, it is preferable not to add a large amount of foaming agent, filler, matting agent, light diffusing agent, softening agent or plasticizer.

It is preferable to use the polymer processing aid (C) for the acrylic resin composition used in the present invention. The polymer processing aid (C) is a compound that is effective in reducing thickness accuracy, film formation stability, and fish eye when molding the resin composition of the present invention. The polymer processing aid (C) is a polymer particle having a particle diameter of 0.05 to 0.5 μm, which can be usually produced by an emulsion polymerization method.
The polymer particles may be single-layer particles composed of polymers having a single composition ratio and a single ultimate viscosity, or multilayer particles composed of two or more kinds of polymers having different composition ratios or ultimate viscosities. You may. Among these, particles having a two-layer structure having a polymer layer having a low ultimate viscosity in the inner layer and a polymer layer having a high ultimate viscosity of 5 dl / g or more in the outer layer are preferable.

When the polymer processing aid (C) is a single-layer particle, it preferably has an ultimate viscosity of 3 to 6 dl / g. If the ultimate viscosity is too small, the effect of improving moldability is low. If the ultimate viscosity is too large, the melt fluidity of the resin composition tends to decrease.

Typical products of polymer processing aid (C) are Kaneka PA series (Kaneka, product name), Metabren P series (Mitsubishi Rayon, product name), Paraloid K series (Dow, product). First name) and so on.

Among these, from the viewpoint of reducing the number of fish eye defects in the film and improving the molding stability during film formation, particularly the molding stability at the edge of the film, methyl methacrylate is 60 to 90% by mass, and alkyl acrylate is 10 to 40. The polymer processing aid (C) containing a mass% is preferable, for example, Metabrene P530, P550 and Paraloid K125 are preferable, and Metabrene P530 is particularly preferable.

The content of the polymer processing aid (C) is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass in total of the methacrylic resin (A) and the block copolymer (B). The lower limit of the content of the polymer processing aid (C) is an appropriate amount depending on the application, but from the viewpoint of reducing fish eyes, it is more preferably 1.0 part by mass or more, and 1.5 parts by mass. It is more preferably parts by mass or more. Further, the upper limit thereof is more preferably 2.5 parts by mass or less, further preferably 2.0 parts by mass or less, and further preferably 1.5 parts by mass or less from the viewpoint of suppressing the cost. preferable.

It is preferable to use an ultraviolet absorber (D) for the acrylic resin composition used in the present invention. The ultraviolet absorber (D) is a compound having an ability to absorb ultraviolet rays, and is said to have a function of mainly converting light energy into heat energy.
Examples of the ultraviolet absorber (D) include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines and the like. These can be used alone or in combination of two or more. Among these, benzotriazoles and hydroxyphenyltriazines are preferable, and hydroxyphenyltriazines are particularly preferable, because they have a high ability to suppress resin deterioration when irradiated with ultraviolet rays and have high compatibility with the resin.

A preferred example of a hydroxyphenyltriazine UV absorber is 2,4-bis (2-hydroxy-4-butyloxyphenyl) -6- (2,4-butyloxyphenyl) -1,3,5-triazine. (Manufactured by BASF: trade name: tinubin 460), 2- (4- (2-hydroxy-3-2 ethyl) hexyl) oxy) -2-hydroxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5 triazine (BASF: trade name: tinubin 405), 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl)- Examples thereof include 1,3,5-triazine (manufactured by BASF: trade name Chinubin 479) and trade names Chinubin 1477, 400, 477, 1600 manufactured by BASF. In addition, 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5- (2- (2-ethylhexanoyloxy) ethoxy) phenol (manufactured by Adeca: trade name Adecastab LA-). 46), 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenoxy) -1,3,5-triazine (manufactured by Adeca: trade name Adecastab LA-F70), and 2- [4-[(2-Hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4 -[(2-Hydroxy-3-tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine.

Among these, hydroxyphenyltriazine-based ultraviolet absorbers having an ester group are preferable from the viewpoint of high weather resistance, for example, 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6. -Bis (4-phenylphenyl) -1,3,5-triazine (manufactured by BASF: Chinubin 479) is preferable.

The content of the ultraviolet absorber (D) is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass in total of the methacrylic resin (A) and the block copolymer (B). The lower limit of the content of the ultraviolet absorber (D) is an appropriate amount depending on the application and the film thickness, but is more preferably 0.2 parts by mass or more, and more preferably 0.4 parts by mass or more. Is more preferable. Further, the upper limit thereof is more preferably 2.5 parts by mass or less, and further preferably 1.5 parts by mass or less from the viewpoint of suppressing the cost.

Further, the resin composition used in the present invention is a methacrylic resin (A), a block copolymer (B), a polymer processing aid (C), and an ultraviolet absorber (D) as long as the effects of the present invention are not impaired. It can be used by mixing with other polymers other than the above. Examples of such other polymers include polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, polynorbornene; ethylene-based ionomers; polystyrene, styrene-maleic anhydride copolymers, high-impact polystyrenes, etc. Styrene-based resins such as AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin; methyl methacrylate-styrene copolymer; polyester resin such as polyethylene terephthalate and polypropylene terephthalate; nylon 6, nylon 66, polyamide elastomer Polypropylene such as polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacetal, polyvinylidene fluoride, polyurethane, modified polyphenylene ether, polyphenylene sulfide, silicone-modified resin; acrylic rubber, silicone rubber; Styrene-based thermoplastic polymers such as SEPS, SEBS and SIS; olefin-based rubbers such as IR, EPR and EPDM can be mentioned.

The method for preparing the resin composition used in the present invention is not particularly limited, but in order to enhance the dispersibility of each component constituting the resin composition, for example, a method of melt-kneading and mixing is recommended. In the method of melt-kneading the methacrylic resin (A) and the block copolymer (B), these and other additives such as the polymer processing aid (C) and the ultraviolet absorber (D) are simultaneously added as needed. It may be mixed, or the methacrylic resin (A) may be mixed with the polymer processing aid (C), the ultraviolet absorber (D) and other additives, and then mixed with the block copolymer (B). Good. The mixing operation can be performed using, for example, a known mixing or kneading device such as a kneader luder, an extruder, a mixing roll, a Banbury mixer. In particular, it is preferable to use a twin-screw extruder from the viewpoint of improving the kneadability and compatibility of the methacrylic resin (A) and the block copolymer (B). The shear rate during melt-kneading is preferably 10 to 1000 / sec. The temperature at the time of mixing / kneading should be appropriately adjusted according to the melting temperature of the methacrylic resin (A), block copolymer (B), etc. used, and is usually mixed at a temperature within the range of 110 to 300 ° C. Then, it is preferable to mix at a temperature in the range of 180 to 300 ° C., more preferably 230 to 270 ° C. When melt-kneading using a twin-screw extruder, it is preferable to use a vent to perform melt-kneading under reduced pressure or under a nitrogen stream from the viewpoint of suppressing coloration. In this way, the resin composition of the present invention can be obtained in any form such as pellets and powders. Resin compositions in the form of pellets, powders and the like are suitable for use as molding materials.
Further, the block copolymer (B) is dissolved in a mixed solution of an acrylic monomer which is a monomer unit of the methacrylic resin (A) and a solvent such as toluene, and the acrylic monomer is polymerized to block the block. A resin composition used in the present invention containing the polymer (B) can also be prepared.

The acrylic resin film formed by molding the resin composition of the present invention can be produced by using a known method such as a T-die method, an inflation method, a melt casting method, or a calender method. From the viewpoint of obtaining a film having good surface smoothness and low haze, a method including a step of extruding the melt-kneaded product from a T-die in a molten state and bringing both sides into contact with a mirror roll surface or a mirror belt surface for molding. Is preferable. The rolls or belts used at this time are preferably made of metal. When both sides of the melt-kneaded product extruded in this way are brought into contact with the mirror surface to form a film, it is preferable to press and sandwich the acrylic resin film with a mirror surface roll or a mirror surface belt. The pinching pressure by the mirror surface roll or the mirror surface belt is preferably high, and the linear pressure is preferably 10 N / mm or more, and more preferably 30 N / mm or more. Further, the surface temperature of the mirror surface roll or the mirror surface belt to be sandwiched is preferably 60 ° C. or higher, more preferably 70 ° C. or higher. Further, the temperature is preferably 130 ° C. or lower, more preferably 100 ° C. or lower. The surface smoothness and haze of the acrylic resin film obtained when the surface temperature of the mirror roll or mirror belt sandwiching the acrylic resin film is less than 60 ° C tends to be insufficient, and when the surface temperature exceeds 130 ° C, the acrylic resin film tends to be insufficient. Since the resin film and the mirror surface roll or mirror surface belt are in close contact with each other, the surface tends to be rough when the acrylic resin film is peeled off from the mirror surface roll or mirror surface belt, and the appearance of the acrylic resin film is impaired due to horizontal wrinkles. It tends to be.

In the case of the manufacturing method by the T-die method, an extruder type melt extruder equipped with a single-screw or twin-screw extrusion screw can be used. The melt extrusion temperature for producing the acrylic resin film of the present invention is preferably 230 ° C. or higher, more preferably 240 ° C. or higher. Further, the temperature is preferably 290 ° C. or lower, more preferably 280 ° C. or lower. In addition, when melt extrusion is performed using a melt extrusion device, a gear pump is attached from the viewpoint of producing a film having a uniform film thickness by melt extrusion under reduced pressure using a vent from the viewpoint of suppressing coloration, and further reducing fish eye defects. It is preferable to attach a polymer filter and melt-extrude the mixture. Further, from the viewpoint of suppressing oxidative deterioration, it is preferable to perform melt extrusion under a nitrogen stream.

When the acrylic resin film of the present embodiment is manufactured by an extruder equipped with a vent, a gear pump, a polymer filter and a T-die, the temperature of the vent, the gear pump, the polymer filter and the T-die is 230 to 290 ° C. It is preferable to control in the range of 240 to 270 ° C. By manufacturing in this temperature range, the film has less deterioration, less fish eye, and excellent mechanical properties and optical characteristics.

The roughness of at least one side of the acrylic resin film of the present invention is 5.0 nm or less, preferably 3.0 nm or less, and more preferably 1.5 nm or less. As a result, the surface smoothness is excellent, the handleability at the time of cutting or punching is excellent, the surface gloss is excellent when used in applications requiring design, and the film of the present invention can be printed. When it is done, it is excellent in the sharpness of the pattern layer and the like. Further, in optical applications, it has excellent optical characteristics such as light transmittance and low haze, and is excellent in accuracy when surface shaping is performed and when a surface fine pattern is applied with a UV curable resin.

The haze of the acrylic resin film of the present invention is 0.7% or less, preferably 0.5% or less, and more preferably 0.3% or less at a thickness of 75 μm. As a result, it is excellent in handleability at the time of cutting or punching, and when it is used for applications requiring design, it is excellent in surface gloss and sharpness of the pattern layer printed on the film of the present invention. .. Further, in optical applications such as a polarizing plate protective film and a light guide film, it is preferable because the utilization efficiency of the light source is improved. Further, it is preferable because it is excellent in shaping accuracy when performing surface shaping.

The yellowness (YI) of the acrylic resin film of the present invention is 1.0 or less, preferably 0.8 or less. As a result, when it is used in an application requiring designability, the color tone change of the pattern layer printed on the film is small and the product has a clear color tone. Further, it is also preferable in optical applications such as a polarizing plate protective film and a light guide film because the color tone change is small and the utilization efficiency of the light source is improved.

The defect of the fish eye having a size of 0.03 mm ² or more in the acrylic resin film of the present invention is 0.2 pieces / m ² or less, preferably 0.15 pieces / m ² or less, and more preferably 0.1 pieces / m ^2. Pieces / m ² or less. As a result, a high-quality film can be obtained in both optical applications and decorative film applications, the number of defective products derived from fish eye defects is reduced, and the yield is improved.

The pencil hardness of the acrylic resin film of the present invention is HB or harder than that, more preferably F or harder than that. A resin film with a hard surface is not easily scratched, so it is generated during the process of manufacturing products such as laminating, as a decorative and surface protective film for the surface of molded products that require design, and also for polarizer protective film applications. It is preferable because it can suppress the occurrence of scratches.

The impact resistance of the acrylic resin film of the present invention is preferably 40 mJ or more, more preferably 50 mJ or more. As a result, even when used as a decorative film, a polarizing plate protective film, or the like, cracking during impact or processing can be suppressed, which is preferable.

The haze temperature dependence of the acrylic resin film of the present invention is preferably smaller. As a result, transparency is not impaired in applications where transparency is required in a wide temperature range or when used at high temperatures, which is advantageous.

The thickness of the acrylic resin film of the present invention is preferably 500 μm or less. If it is thicker than 500 μm, secondary processability such as laminateability, handleability, cutability and punching property will deteriorate, making it difficult to use as a resin film and increasing the unit price per unit area, which is economically disadvantageous. Therefore, it is not preferable. The thickness of the acrylic resin film is more preferably 30 μm or more, further preferably 50 μm or more. Further, 300 μm or less is more preferable, and 200 μm or less is further preferable.

The acrylic resin film of the present invention may be stretched. By the stretching treatment, the mechanical strength is increased, and a resin 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, a tuber stretching method, and a rolling method. The temperature at the time of stretching is 5 ° C. higher than the glass transition temperature of the methacrylic resin and the upper limit is 40 ° C. higher than the glass transition temperature of the methacrylic resin from the viewpoint that the resin film can be uniformly stretched and has high strength. It is a high temperature. If the stretching temperature is too low, the molded product is likely to break during stretching, and if the stretching temperature is too high, the effect of the stretching treatment is not sufficiently exhibited and the strength of the molded product is difficult to increase. Stretching is usually performed at 100-5000% / min. If the stretching speed is low, the strength is unlikely to increase, and the productivity also decreases. Further, if the stretching speed is high, uniform stretching may be difficult due to breakage of the molded product or the like. Further, it is more preferable to perform heat fixing after stretching. By heat fixing, a film with less heat shrinkage can be obtained. The thickness of the film obtained by stretching is preferably 10 to 200 μm.

The acrylic resin film may be colored. As a coloring method, a pigment or dye is contained in the composition itself of the acrylic resin (A) and the triblock copolymer (B) to color the resin itself before film formation; the dye is dispersed. Examples thereof include a dyeing method in which an acrylic resin film is immersed in a liquid to color it, but the method is not particularly limited thereto.

The acrylic resin film may be printed on at least one side. Patterns and colors such as patterns, characters, and figures are added by printing. The pattern may be chromatic or achromatic. In order to prevent fading of the printing layer, printing is preferably performed on the side in contact with another thermoplastic resin or thermosetting resin described later.

In the acrylic resin film of the present invention, at least one layer of (i) a layer made of a metal and / or a metal oxide, (ii) a thermoplastic resin layer and (iii) a base material layer is laminated on at least one surface. It may be a film. The method of laminating the other layers is not particularly limited, and the layers can be joined directly or via an adhesive layer. As the base material layer, for example, a wooden base material, non-wooden fibers such as kenaf, or the like may be used. These layers can be laminated with one layer or a plurality of layers.

The acrylic resin film of the present invention can be laminated with the other layers described above on at least one surface. The thickness of the laminated film of the present invention may vary depending on the application and is not limited, but is preferably 500 μm or less from the viewpoint of secondary processability.
Other thermoplastic resins suitable for lamination include polycarbonate resin, polyethylene terephthalate resin, polyamide resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, other (meth) acrylic resin, and ABS (acrylonitrile-butadiene-). (Styrene copolymerization), ethylene vinyl alcohol resin, polyvinyl butyral resin, polyvinyl acetal resin, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, acrylic-based thermoplastic elastomer and the like.

The method for producing the laminated film is not particularly limited. For example, (1) a method of preparing an acrylic resin film and another thermoplastic resin film separately and continuously laminating them between heating rolls, a method of heat-pressing with a press, a method of press-pressing or vacuum forming at the same time. Laminating method, laminating method with an adhesive layer interposed therebetween (wet lamination); (2) Laminating another thermoplastic resin melt-extruded from a T-die using an acrylic resin film as a base material; (3) By co-extruding a mixture of the above-mentioned methacrylic resin (A) and the above-mentioned triblock copolymer (B) and another thermoplastic resin, the acrylic resin film and the layer of the other thermoplastic resin film are laminated. Examples thereof include a method of obtaining a film.
Of these methods, in the method (1) or (2), a surface treatment such as a corona treatment may be applied to the bonding surface side of the resin film or another thermoplastic resin film before laminating.

The acrylic resin film of the present invention may be used alone, as an inner layer or a part thereof, or as an outermost layer. There is no particular limitation on the number of laminated films. As the other resin used for laminating, a transparent resin such as an acrylic resin is preferable from the viewpoint of film design. From the viewpoint that the film is not easily scratched and the design is long-lasting, the outermost layer preferably has high surface hardness and weather resistance, and the acrylic resin film of the present invention is preferable.

The acrylic resin film of the present invention is also suitably used as an optical film. Specifically, it is used in a polarizer protective film, a polarizing plate using the polarizing element, a liquid crystal display device including at least one polarizing plate thereof, an organic EL display device, an image display device such as a PDP, and the like. Furthermore, optical substrates such as light guide films, moth-eye films, frennel lenses, lenticular lenses, front films of various displays, diffusion films, glass shatterproof, liquid crystal ASF films, transparent conductive films, heat shield films, and various barrier films. It is preferably used as a film.

The acrylic resin film of the present invention is a film having high transparency, surface smoothness, surface hardness, excellent impact resistance, and few fish eye defects. Taking advantage of these excellent features, it can be suitably used for products requiring design and optical applications.

The film of the present invention is a molded product that requires good design and a molded product that requires high optical properties, that is, by taking advantage of good handleability, good surface smoothness, few fisheye defects, and high surface hardness. , Advertising towers, stand signs, sleeve signs, column signs, roof signs, and other signboard parts; showcases, dividers, store displays, and other display parts; fluorescent light covers, mood lighting covers, lamp shades, light ceilings, light walls, Lighting parts such as chandeliers; Interior parts such as furniture, pendants, mirrors; Building parts such as doors, dome, safety window glass, partitions, staircase wainscots, balcony wainscots, roofs of leisure buildings; aircraft windshields, pilot visors , Motorcycles, motor boat windshields, light-shielding plates for buses, side visors for automobiles, rear visors, head wings, headlight covers, automobile interior parts, automobile exterior parts such as bumpers, and other transportation equipment-related parts; nameplates for audiovisual images, stereo covers, Electronic equipment parts such as TV protective masks, vending machines, mobile phones, personal computers; Medical equipment parts such as incubators and roentgen parts; Equipment-related parts such as machine covers, instrument covers, experimental equipment, rulers, dials, observation windows, etc. Traffic-related parts such as road signs, information boards, curved mirrors, soundproof walls; Others, greenhouses, large water tanks, box water tanks, bathroom parts, clock panels, bathtubs, sanitary, desk mats, game parts, toys, faces during welding Decorative film / protective film on the surface of protective masks, wallpaper; It is preferably used as a marking film.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples. In addition, the present invention includes all aspects in which the above-mentioned matters representing technical features such as characteristic values, forms, manufacturing methods, and uses are arbitrarily combined. The physical property values in the examples and comparative examples were measured by the following methods.

[Ratio of each structural unit]
The ratio of each structural unit of the methacrylic resin and the triblock copolymer was calculated from the amount of each monomer charged.

[Melting viscosity]
The melt viscosities of the methacrylic resin (A) and the block copolymer (B) at 220 ° C. and a shear rate of 122 / sec were measured using a capillograph (model 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 220 ° C. It was extruded from a 10 mm polymer at a piston speed of 10 mm / min, and the value was evaluated from the shear stress generated at that time.

[Manufacturing of film]
A gear pump and a polymer filter with a filtration accuracy of 10 μm are installed in a 65 mmΦ uniaxial extruder with a vent, and a melt extruder with a 900 mm wide T-die at the tip is used to achieve an extrusion temperature of 250 ° C and a discharge rate of 40 kg / h. The film was extruded and sandwiched between a metal mirror elastic roll at 80 ° C. and a metal mirror rigid body roll at 80 ° C. to form a film, which was taken up at 10 m / min to form a film having a thickness of 75 μm.

[Surface roughness (measurement of film surface smoothness)]
A film formed under the above-mentioned film forming conditions was cut out to a size of 5 mm × 5 mm and used as a test piece. The surface shape was measured in DFM mode using an atomic force microscope (SPI4000 probe station E-sweep environmental control unit manufactured by SII Nanotechnology). The probe used was SI-DF20 (back surface Al) manufactured by SI Nanotechnology. Prior to sample measurement, a reference sample with a pitch of 10 μm and a step of 100 nm was measured, and the X-axis and Y-axis measurement errors of the device were 5% or less with respect to 10 μm, and the Z-axis error was 5% or less with respect to 100 nm. It was confirmed.

The observation area of the sample was 5 μm × 5 μm, and the measurement frequency was 0.5 Hz. The number of scan lines was 512 on the X-axis and 512 on the Y-axis. The measurement was performed in an air environment of 25 ° C. ± 2 ° C. and a humidity of 30 ± 5%. The obtained measurement data was analyzed by the data processing software attached to the apparatus, and the average surface roughness Ra was obtained. That is, select the [3rd order tilt correction] command from the [Tool] menu of the measurement software of the device, correct the tilt of the film and the entire tilt of the large waviness, and then execute the [Surface roughness analysis] command from the [Analysis] menu. The selection was made to obtain an average surface roughness Ra. The average surface roughness Ra is a value obtained by averaging the absolute values of the deviations from the reference surface to the designated surface, and is defined by the following equation.

ここでＦ（Ｘ，Ｙ）は（Ｘ，Ｙ）座標での高さの値を表す。Ｚ₀は以下で定義されるＺデータの平均値を表す。

Here, F (X, Y) represents the height value in the (X, Y) coordinates. Z ₀ represents the average value of Z data defined below.

また、Ｓ₀は、測定領域の面積を表す。

Further, S ₀ represents the area of the measurement area.

This average surface roughness Ra was measured in 10 different regions on both sides of the film (referred to as A and B surfaces for convenience), and the average value of the average surface roughness Ra at 10 locations was taken as the roughness of the film surface. .. The third-order tilt correction was performed by fitting the measured sample surface on a third-order curved surface by least squares approximation, in order to eliminate the influence of the tilt and waviness of the film sample.

[Film haze]
The film obtained under the above conditions was cut into 50 mm × 50 mm pieces to obtain test pieces, and the haze was measured at 23 ° C. in accordance with JIS K7136.

[Yellowness of film]
The film obtained under the above conditions was cut into 50 mm × 50 mm pieces to obtain test pieces, and the yellowness was measured at 23 ° C. in accordance with JIS K7373.

[Film fish eye drawbacks]
A 300 m roll of film manufactured under the above conditions is passed through an online defect inspector (Santec8000C1 System3 manufactured by Nagase & Co., Ltd.) to measure the number of fish eye defects with a size of 0.03 mm ² or more, and fish eyes per 1 m ^2. The number of defects was calculated.

[Pencil hardness of film]
The film produced under the above conditions was cut into 10 cm × 10 cm pieces to obtain test pieces, and the pencil hardness was measured according to JIS-K5600-5-4.

[Impact resistance]
A film was attached to a steel mounting plate having an open gap, and an iron ball weighing 20 g was freely dropped onto the film in the gap portion. The height of free fall was changed in increments of 10 cm, and the impact resistance was evaluated from the maximum height at which it did not break.

[Heating temperature whitening (haze temperature dependence)]
Using the film produced under the above conditions, a 50 mm × 50 mm test piece was cut out, haze (before heating) was measured according to JIS K7136, and then left in an oven at 80 ° C. for 10 minutes. The test piece was taken out from the oven, and the haze (after heating) was measured by a haze meter (haze meter HM-150 manufactured by Murakami Color Technology Research Institute) in accordance with JIS K7136, and the test piece was judged according to the following evaluation criteria. Here, the change in haze is expressed by the following equation.
Change in haze = haze (after heating) -haze (before heating)
Excellent: The change in haze is 0.1% or less.
Good: The change in haze is greater than 0.1% and less than 0.5%. Slightly bleached.
Poor: Haze change is greater than 0.5%.

In the reference examples shown below, the compound was dried and purified by a conventional method and degassed with nitrogen. In addition, the transfer and supply of the compound was carried out in a nitrogen atmosphere.

Reference Example 1 [Synthesis of methacrylic resin (A-1)]
Polymerization initiator (2,2'-azobis (2-methylpropionitrile), hydrogen extraction capacity: 1%, 1 hour half-life temperature: 83 ° C.) 0.1 on a monomer consisting of 100 parts by mass of methyl methacrylate 0.21 parts by mass and 0.21 parts by mass of a chain transfer agent (n-octyl mercaptan) were added and dissolved to obtain a raw material solution.
100 parts by mass of ion-exchanged water, 0.03 part by mass of sodium sulfate and 0.45 parts by mass of suspension dispersant were mixed to obtain a mixed solution. 420 parts by mass of the mixed solution and 210 parts by mass of the raw material solution were charged into the pressure-resistant polymerization tank, and the polymerization reaction was started at a temperature of 70 ° C. while stirring in a nitrogen atmosphere. After 3 hours from the start of the polymerization reaction, the temperature was raised to 90 ° C. and stirring was continued for 1 hour to obtain a liquid in which the bead-like copolymer was dispersed. Although some polymer adhered to the wall surface of the polymerization tank or the stirring blade, the polymerization reaction proceeded smoothly without foaming.
The obtained copolymer dispersion is washed with an appropriate amount of ion-exchanged water, the beaded copolymer is taken out by a bucket centrifuge, dried in a hot air dryer at 80 ° C. for 12 hours, and the beaded methacrylic resin is dried. (A) (hereinafter referred to as "methacrylic resin (A-1)") was obtained.
The obtained methacrylic resin (A-1) had a methyl methacrylate content of 100% by mass, and had a melt viscosity (η (A)) of 220 ° C. and a shear rate of 122 / sec of 3000 Pa · s.

Reference Example 2 [Synthesis of methacrylic resin (A-2)]
The monomer used was changed to 99 parts by mass of methyl methacrylate and 1 part by mass of methyl acrylate, and the amount of the chain transfer agent was changed to 0.24 parts by mass in the same manner as in Reference Example 1. A-2) was polymerized and produced. The obtained methacrylic resin (A-2) had a methyl methacrylate content of 99% by mass, and had a melt viscosity (η (A)) of 220 ° C. and a shear rate of 122 / sec of 2780 Pa · s.

Reference Example 3 [Synthesis of Triblock Copolymer (B-1)]
In a toluene solution, under the catalyst of hexamethyltriethylenetetramine and isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, sec-butyllithium was polymerized as a polymerization initiator. After 20 parts by mass of methyl methacrylate was added dropwise to polymerize the methacrylic acid ester polymer block (b2-1), 50 parts by mass of n-butyl acrylate was added dropwise to form the methacrylic acid ester polymer block (b1). After polymerization, 30 parts by mass of methyl methacrylate was added dropwise to polymerize the methacrylic acid ester polymer block (b2-2), and finally the mixture was stopped with methanol to obtain a triblock copolymer (B-1). .. The obtained triblock copolymer has a triblock structure of (b2-1)-(b1)-(b2-2), and has a triblock structure of (b2-1)-(b1)-(b2-2). The composition ratio was 30% by mass-50% by mass-20% by mass. The content of (b2) was 50 parts by mass. Therefore, the block (b2-1) and the block (b2-2) are larger in the block (b2-1) than in the block (b2-2) when the triblock copolymer (B) is 100% by mass. The value of the mass ratio is large, and the ratio of the mass ratio (n (H)) of the block (b2-1) to the mass ratio (n (L)) of the block (b2-2), that is, n (H) / n (L). ) Was 1.5. The melt viscosity (η (B)) of the triblock copolymer (B-1) at 220 ° C. and a shear rate of 122 / sec was 377 Pa · s.

Reference Example 4 [Synthesis of Triblock Copolymer (B-2)]
The molecular weight was adjusted by adjusting the polymerization initiator under the same solvent and catalytic conditions as in Reference Example 3, and the amount of the polymerizable monomer was adjusted to adjust the methyl methacrylate polymer block (b2-1) -acrylic acid. A triblock copolymer (B-2) having a structure of a butyl polymer block (b1) -methyl methacrylate polymer block (b2-2) was obtained. Since the composition ratio of (b2-1)-(b1)-(b2-2) was 15% by mass-70% by mass-15% by mass, the block (b2-) with respect to the mass ratio of the block (b2-2). The value of the mass ratio ratio of 1) was 1. The melt viscosity (η (B)) of the obtained triblock copolymer (B-2) at 220 ° C. and a shear rate of 122 / sec was 650 Pa · s.

Reference Example 5 [Synthesis of diblock copolymer (B-3)]
The molecular weight was adjusted by adjusting the polymerization initiator under the same solvent and catalytic conditions as in Reference Example 3, and the amount of the polymerizable monomer was adjusted to adjust the methyl methacrylate polymer block (b2) -n-acrylic acid. A diblock copolymer (B-3) having a block (b1) structure composed of butyl / benzyl acrylate = 50/50 (mass ratio) was obtained. The composition ratio of (b2)-(b1) was 50% by mass-50% by mass. The melt viscosity (η (B)) of the obtained diblock copolymer (B-3) at 220 ° C. and a shear rate of 122 / sec was 87 Pa · s.

The polymer processing aid (C) used in the examples is described below. Here, MMA means a structural unit derived from methyl methacrylate, and BA means a structural unit derived from butyl acrylate or butyl methacrylate.

C-1: Product name Metabrene P530A manufactured by Mitsubishi Rayon Co., Ltd. (Average degree of polymerization: 24455, MMA 80% by mass / BA 20% by mass)
C-2: Product name Pararoid K125P manufactured by Kureha Corporation (average degree of polymerization: 1974, MMA 79% by mass / BA21% by mass)

(Average degree of polymerization of polymer processing aid)
Using an automatic dilution type capillary viscosity meter (Uberode type, capillary inner diameter = 0.5 mm), measurement was performed at 20 ° C. using chloroform as a solvent, and the degree of polymerization was determined in terms of PMMA.

(Example 1)
85 parts by mass of methacrylic resin (A-1), 15 parts by mass of triblock copolymer (B-1), 1.5 parts by mass of polymer processing aid (C-1), UV inhibitor (BASF: Commodity) Name Chinubin 479) 1 part by mass was melt-kneaded at 260 ° C. with a 41 mmΦ twin-screw extruder, extruded into strands, and cut with a pelletizer to produce pellets of the resin composition.
The obtained resin composition is extruded by installing a gear pump and a polymer filter having a filtration accuracy of 10 μm in the above-mentioned 65 mmΦ uniaxial extruder with a vent, and using a melt extruder having a T-die with a width of 900 mm at the tip. Extruded at a temperature of 250 ° C. and a discharge rate of 40 kg / h, sandwiched between a metal mirror elastic roll at 80 ° C. and a metal mirror rigid body roll at 80 ° C. to form a film, which is taken up at 10 m / min to form a film having a thickness of 75 μm. did. The number of fisheye defects was inspected online at the time of film formation, and the surface roughness, haze, yellowness, pencil hardness, impact resistance, and heating temperature whitening (80 ° C.) were measured using the obtained film. Table 1 shows these results.

(Examples 2 to 4)
A film was obtained by the same method as in Example 1 except that the formulation shown in Table 1 was followed, and the physical properties were evaluated by the same method. The results are shown in Table 1. The "ultraviolet absorber (ADEKA STAB LA31RG)" in the table refers to the trade name ADEKA STAB LA31RG manufactured by ADEKA CORPORATION.

(Comparative Examples 1-2)
A film was obtained by the same method as in Example 1 except that the formulation shown in Table 1 was followed, and the physical properties were evaluated by the same method. The results are shown in Table 1.

Claims (13)

A methacrylic resin (A) having a structural unit derived from methyl methacrylate in an amount of 80% by mass or more and having a melt viscosity (η (A)) of 1500 to 3500 Pa · s at 220 ° C. and a shear rate of 122 / sec .
A block in which a methacrylic acid ester polymer block (b2) is bonded to an acrylic acid ester polymer block (b1), and a melt viscosity (η (B)) at 220 ° C. and a shear rate of 122 / sec is 300 to 700 Pa · s. Copolymer (B); and
Includes Polymer Processing Aid (C) containing 60-90% by weight of methyl methacrylate and 10-40% by weight of alkyl acrylate;
70 to 99 parts by mass of the methacrylic resin (A) and 1 to 30 parts by mass of the block copolymer (B) with respect to a total of 100 parts by mass of the methacrylic resin (A) and the block copolymer (B). , Polymer processing aid (C) is 0.1 to 3 parts by mass;
The value of the ratio (η (A) / η (B)) of the melt viscosity (η (A)) to the melt viscosity (η (B)) is 6 to 8; an acrylic resin film composed of an acrylic resin composition. A fish having a surface roughness of 1.1 nm or more and 5 nm or less, a haze of 0.1% or more and 0.7% or less, a yellowness of 0.4 or more and 1.0 or less, and a size of 0.03 mm ² or more. Acrylic resin film whose eye defects are 0.09 pieces / m ² or more and 0.2 pieces / m ² or less when 100 m ² is measured with an online defect tester . The acrylic resin film according to claim 1, wherein the pencil hardness on at least one side is HB or harder than that. The acrylic resin film according to claim 1 or 2, which has an impact resistance of 40 mJ or more. Claim 1, wherein the block copolymer (B), characterized in that it contains 40 to 70 wt% of acrylic acid ester polymer block (b1) 30 to 60% by weight and a methacrylic acid ester polymer block (b2) The acrylic resin film according to any one of 3 to 3 . The acrylic resin film according to any one of claims 1 to 4 , wherein the block copolymer (B) is a triblock copolymer. In the triblock copolymer (B), the mass ratios of the two methacrylic acid ester polymer blocks (b2) bonded to both ends of the acrylic acid ester polymer block (b1) are different from each other.
In the two methacrylic ester polymer blocks (b2), the methacrylic acid having a larger mass ratio to the mass ratio (n (L)) of the methacrylic ester polymer block (b2 (L)) having a smaller mass ratio. The fifth aspect of claim 5, wherein the value of the mass ratio (n (H)) ratio (n (H) / n (L)) of the ester polymer block (b2 (H)) is 1.5 or more. The acrylic resin film described. The acrylic resin composition contains 0.1 to 3 parts by mass of an ultraviolet absorber (D) with respect to a total of 100 parts by mass of the methacrylic resin (A) and the block copolymer (B). The acrylic resin film according to any one of claims 1 to 6 , wherein the acrylic resin film is characterized. A stretched film made of the acrylic resin film according to any one of claims 1 to 7 . An optical film comprising the acrylic resin film according to any one of claims 1 to 7 or the stretched film according to claim 8 . A polarizing element protective film, which comprises using the acrylic resin film according to any one of claims 1 to 7 or the stretched film according to claim 8 . A polarizing plate comprising at least one of the polarizer protective film according to claim 1 0. A decorative film characterized in that the surface of either the acrylic resin film according to any one of claims 1 to 7 or the stretched film according to claim 8 is decorated. .. The method for producing the acrylic resin film according to any one of claims 1 to 7 with an extruder equipped with a T-die, wherein the extruder is provided with a vent, a gear pump, and a polymer filter, and is vented. A method for producing an acrylic resin film, which comprises controlling the temperature of a gear pump, a polymer filter, and a T-die in a range of 230 to 290 ° C.