JP5378692B2 - Acrylic resin film and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic resin film having good film handleability, high surface hardness, and high surface smoothness with almost no surface defects. <P>SOLUTION: The acrylic resin film is manufactured by melting and kneading a metacrylic resin [A] having a weight average molecular weight of 40,000 or more and a polyvinyl acetal resin [B] with an acetalation degree ranging from 55 to 83 mol% obtained via (co)acetalation of a polyvinyl alcohol resin with a number average polymerization degree ranging from 200 to 4,000 at a mass ratio ([A]/[B]) ranging from 99/1 to 51/49, so as to obtain a resin composition having a glass transition temperature Tg<SB>AP</SB>resulting from the metacrylic resin (A) between the glass transition temperature Tg<SB>A</SB>of the metacrylic resin (A) alone and the glass transition temperature Tg<SB>B</SB>of the polyvinyl acetal resin (B) alone, extruding the melt of the resin composition from T die, and then causing the both faces thereof to come into contact with a mirror finished roll surface or a mirror finished belt surface. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention provides an acrylic resin film having excellent handleability and surface smoothness while maintaining the excellent characteristics of an acrylic resin such as transparency, weather resistance, and surface hardness, and an excellent balance of rigidity and toughness, and its It relates to a manufacturing method. In particular, the present invention relates to an acrylic resin film that does not whiten when stretched, bent, subjected to an impact, and / or left to stand for a long time under moist heat, and a method for producing the same.

  For car interiors, exteriors and wallpaper of home appliances, decoration and design with wood grain and other designs and protection of base materials (automobile interiors, exteriors of home appliances, wallpaper, etc.) A transparent resin film is used for the purpose of imparting or imparting weather resistance. Among them, the acrylic resin film is widely used as a decorative film having a protective function of a base material because it is excellent in transparency, weather resistance, and surface hardness.

  However, a film made only of a methacrylic resin is not only very brittle and difficult to form a film, but also has a very poor handleability, and when trimming at the same time as the film is formed, When pasting with a base material, or when removing an unnecessary part (burr) after pasting with a base material, problems, such as cracking, may occur.

Therefore, in order to improve the brittleness of a film made of only this methacrylic resin, an acrylic resin film blended with so-called core-shell type particles has been proposed.
For example, Patent Document 1 discloses a core-shell type particle (common name: two-layer type core) obtained by copolymerizing a methacrylic acid alkyl ester and an acrylic acid alkyl ester in the presence of crosslinked particles of an acrylic acid alkyl ester polymer. An acrylic resin film obtained by blending shell-type particles with a methacrylic resin has been proposed.
Japanese Examined Patent Publication No. 56-27378

The acrylic resin film blended with the two-layer type core-shell type particles generally has a low surface hardness. Therefore, in order to improve the acrylic resin film, the so-called three-layer type core-shell type particles (Patent Document 2) and An acrylic resin film blended therewith (Patent Documents 3 and 4) has been proposed. When the surface hardness of the acrylic resin film is increased, the scratch resistance of the film is improved, which is advantageous as a protective film.
Japanese Patent Publication No.55-27576 Japanese Patent No. 3287255 Japanese Patent No. 3287315

  By the way, since the core-shell type particles themselves are crosslinked, they do not have fluidity. Therefore, when the core-shell type particles are blended with a methacrylic resin, a part of the core-shell type particles is formed from the surface of the film formed through a film forming process (for example, melt molding or inflation molding using a T die). It was inevitable that the protrusion protruded, which reduced the surface smoothness of the acrylic resin film.

  In particular, since the three-layer type core-shell type particles are generally less deformable than the two-layer type core-shell type particles, the acrylic resin film using the three-layer type core-shell type particles has two layers. Although the surface hardness is higher than that using the core-shell type particles, the surface smoothness is significantly reduced.

  Deterioration of the surface smoothness of the film is caused by cracking of the film when the film is cut after film formation, when the film is bonded to the base material, or when unnecessary portions (burrs) are removed after being bonded to the base material. The tendency to increase ease.

  Therefore, as a film having high surface smoothness and capable of expressing good design properties even when a metal and / or metal oxide layer is formed on the film, Patent Document 5 discloses an acrylic melt-extruded from a T die. Containing acrylic rubber particles obtained by forming a film containing acrylic rubber particles-containing acrylic resin sandwiched between two mirror rolls at a pressing pressure of 300 N / cm or more, and containing at least one of the acrylic rubber particles. An acrylic resin film has been proposed in which the center line average roughness Ra specified in JIS B0601 is 0.01 to 0.05 μm.

By the way, in patent document 5, Ra is measured with a surface roughness meter ["Surfcom 570A type" manufactured by Tokyo Seimitsu Co., Ltd.] using a measuring stylus having a radius of 3 [mu] m. According to the study by the present inventors, the size of this measurement stylus is much larger than that of core-shell type particles (usually several tens to several hundreds of nm), so the degree of protrusion of the core-shell type particles can be accurately determined. It was found that it was not evaluated. Further, it was found that even if there were aggregated core-shell type particles (usually several hundred nm to 1 μm), they were not reflected so much in Ra. Therefore, even if the acrylic resin film has a center line average roughness Ra in the above range, it is unnecessary when cutting the film after film formation, when bonding the film to the substrate, or after bonding to the substrate. When removing parts (burrs) etc., it is not possible to sufficiently prevent unintentional cracking of the film starting from defects caused by protruding core-shell type particles or aggregated core-shell type particles It was.
Japanese Patent Laid-Open No. 2003-253016

Thus, it has been very difficult to satisfy the handleability, surface hardness, and surface smoothness of the acrylic resin film at the same time only by blending the core-shell type particles.
When using acrylic resin films for LCD protective films, light guide films, Fresnel lenses, lenticular lenses, front films for various displays, optical parts such as diffusion films, etc. High surface smoothness such as few defects is required. Further, when shaping the film surface, the surface roughness of the film serving as the base material affects the shaping accuracy, so that very high surface smoothness is also required in this respect.

By the way, Non-Patent Document 1 discloses that a blend of 50 parts by mass of a methyl methacrylate resin and 50 parts by mass of polyvinyl butyral is dissolved in a solvent and cast to obtain a film. This film has a phase separation structure in which methyl methacrylate resin is dispersed in various sizes. Since this film uses a solvent at the time of film formation, it has not only low productivity but also has problems such as contamination of the film forming environment. Moreover, the film using low molecular weight polymethyl methacrylate was not sufficiently handled. Even when high molecular weight polymethyl methacrylate was used, a film having sufficient handleability could not be obtained because melt kneading was not performed.
Macromolecules, Vol.34, 4277 (2001)

  An object of the present invention is to provide an acrylic resin film having good surface smoothness with good handleability, high surface hardness and almost no surface defects.

Therefore, as a result of intensive studies to solve the above problems, the present inventors melt-kneaded a specific methacrylic resin and a specific polyvinyl acetal resin at a specific mass ratio, and the methacrylic resin ( the resin composition having a glass transition temperature Tg _AP due to methacrylic resin (a) between the glass transition temperature Tg _B in the glass transition temperature Tg _a in a) alone polyvinyl acetal resin (B) alone By forming the resin composition into a film by a specific method, while maintaining the excellent characteristics of the acrylic resin such as transparency, weather resistance, and surface hardness, it has good handleability and high surface smoothness. It was found that a good film could be obtained. The present invention has been further studied and completed based on this finding.

That is, the present invention includes the following aspects.
(1) Polyvinyl having an acetalization degree of 55 to 83 mol% obtained by (co) acetalizing a methacrylic resin [A] having a weight average molecular weight of 40000 or more and a polyvinyl alcohol resin having a number average polymerization degree of 200 to 4000 The acetal resin [B] is contained in a mass ratio ([A] / [B]) 99/1 to 51/49, and the glass transition temperature Tg _{A of the} methacrylic resin (A) alone and the polyvinyl acetal resin. (B) has a glass transition temperature Tg _AP due to methacrylic resin (a) between the glass transition temperature Tg _B alone, and at least an acrylic roughness of one surface is 1.5nm or less Resin film.
(2) The acrylic resin film as described in (1) whose haze measured according to JIS K7136 is 0.3% or less.
(3) The acrylic resin film according to (1) or (2), which has a pencil hardness of HB or higher.
(4) The methacrylic resin [A] and the polyvinyl acetal resin [B] are melt-kneaded, extruded from a T-die in a molten state, and both surfaces of the methacrylic resin [A] are brought into contact with a mirror roll surface or a mirror belt surface and molded. The acrylic resin film according to any one of (1) to (3).
(5) The acrylic resin film according to any one of (1) to (4), wherein printing is performed on at least one side.

(6) Polyvinyl having an acetalization degree of 55 to 83 mol% obtained by (co) acetalizing a methacrylic resin [A] having a weight average molecular weight of 40000 or more and a polyvinyl alcohol resin having a number average polymerization degree of 200 to 4000. The acetal resin [B] is melt-kneaded at a mass ratio ([A] / [B]) of 99/1 to 51/49 at a resin temperature of 140 ° C. or higher while shearing at a shear rate of 100 sec ⁻¹ or higher. The manufacturing method of the acrylic resin film as described in said (1)-(5) including the process cooled to the temperature of 120 degrees C or less.
(7) when melt-kneaded at a resin temperature of 140 ° C. or higher, undergoes at least twice applying a shear or shear rate 100 sec ^-1, and a step of the shear rate to 50 sec ^-1 or less, (6) The manufacturing method of the acrylic resin film of description.
(8) Polyvinyl having an acetalization degree of 55 to 83 mol% obtained by (co) acetalizing a methacrylic resin [A] having a weight average molecular weight of 40000 or more and a polyvinyl alcohol resin having a number average polymerization degree of 200 to 4000. The acetal resin [B] is melt-kneaded at a mass ratio ([A] / [B]) 99/1 to 51/49, and the glass transition temperature Tg _{A of the} methacrylic resin (A) alone and the polyvinyl Obtaining a resin composition having a glass transition temperature Tg _AP due to the methacrylic resin (A) between the acetal resin (B) and the glass transition temperature Tg _B alone,
A method for producing an acrylic resin film, comprising a step of extruding the resin composition in a molten state from a T-die and bringing both surfaces into contact with a mirror roll surface or a mirror belt surface.

(9) A laminate comprising the film according to any one of (1) to (5) provided on the surface of a thermoplastic resin and / or a thermosetting resin.
(10) including a step of inserting the film according to any one of (1) to (5) between injection-moulded male and female molds and injecting a thermoplastic resin into the mold from one surface of the film. The manufacturing method of a laminated body.
(11) A laminate obtained by the production method according to (10).
(12) A laminated film in which at least one other thermoplastic resin layer is provided on at least one surface of the film according to any one of (1) to (5).
(13) A laminate in which the laminated film according to (12) is provided on the surface of a thermoplastic resin and / or a thermosetting resin.
(14) Insert the laminated film according to (12) between injection-moulded male and female molds,
The manufacturing method of a laminated body including the process of inject | pouring a thermoplastic resin from the one side of this laminated | multilayer film in this metal mold | die.
(15) A laminate obtained by the production method according to (14).

  The acrylic resin film of the present invention is a film having the characteristics of a methacrylic resin itself such as transparency and surface hardness, and it has handling characteristics, surface hardness and surface smoothness which cannot be achieved by conventional acrylic resin films. Achieving balance. The acrylic resin film of the present invention can be suitably used for products requiring design properties and optical applications, taking advantage of this excellent feature.

Hereinafter, the present invention will be described in detail.
The acrylic resin film of the present invention is a film containing a methacrylic resin [A] and a polyvinyl acetal resin [B].

The methacrylic resin [A] used in the present invention can be obtained by polymerizing a monomer mixture containing an alkyl methacrylate.
As alkyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, myristyl Examples thereof include methacrylate, palmityl methacrylate, stearyl methacrylate, behenyl methacrylate, cyclohexyl methacrylate, and phenyl methacrylate. Of these, alkyl methacrylates having 1 to 4 carbon atoms in the alkyl group are preferred, and methyl methacrylate is particularly preferred. These alkyl metallates may be used alone or in combination of two or more.

Examples of monomers other than alkyl methacrylate include alkyl acrylate. Other ethylenically unsaturated monomers that can be copolymerized with alkyl methacrylate and alkyl acrylate are also included.
As alkyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, myristyl Examples include acrylate, palmityl acrylate, stearyl acrylate, behenyl acrylate, cyclohexyl acrylate, and phenyl acrylate. Of these, alkyl acrylates having 1 to 8 carbon atoms in the alkyl group are preferred. These alkyl acrylates may be used alone or in combination of two or more.

  Examples of the ethylenically unsaturated monomer copolymerizable with alkyl methacrylate and alkyl acrylate include diene compounds such as 1,3-butadiene and isoprene; styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, Styrene substituted with halogen, 1-vinylnaphthalene, 4-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, etc. Vinyl aromatic compounds; ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, acrylamide, methacrylamide, maleic anhydride, maleic imide, monomethyl maleate, dimethyl maleate, etc. It is possible. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

In the methacrylic resin [A] used in the present invention, the proportion of the alkyl methacrylate unit is preferably 50 to 100% by mass and more preferably 80 to 99.9% by mass from the viewpoint of weather resistance. .
Moreover, it is preferable to contain an alkyl acrylate unit in 0.1-20 mass% from a heat resistant viewpoint of methacrylic resin [A].

  The methacrylic resin [A] used in the present invention has a weight average molecular weight (denoted as Mw, the same shall apply hereinafter) of 40,000 or more, preferably 40,000 to 10,000, from the viewpoint of strength characteristics and meltability. 000, more preferably 80,000 to 1,000,000. The methacrylic resin (A) used in the present invention may be one in which monomers are linearly bonded, may have a branch, or may have a cyclic structure. good.

  The methacrylic resin [A] used in the present invention is not particularly limited as long as it is a method capable of polymerizing an α, β-unsaturated compound, but is preferably produced by radical polymerization. Examples of the polymerization method include bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization.

  Examples of radical polymerization initiators used during polymerization include azo compounds such as azobisisobutyronitrile and azobisγ-dimethylvaleronitrile; benzoyl peroxide, cumyl peroxide, oxyneodecanoate, diisopropyl peroxydicarbonate, t Examples thereof include peroxides such as -butyl cumyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, and lauroyl peroxide. The polymerization initiator is usually used in an amount of 0.05 to 0.5 parts by mass with respect to 100 parts by mass of all monomers. The polymerization is usually performed at a temperature of 50 to 140 ° C., usually for 2 to 20 hours.

  A chain transfer agent can be used to control the molecular weight of the methacrylic resin [A]. Examples of chain transfer agents include methyl mercaptan, ethyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, t-butyl mercaptan, n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, ethylthioglycoate, mercaptoethanol, thio- β-naphthol, thiophenol and the like can be mentioned. A chain transfer agent is normally used in 0.005-0.5 mass% with respect to all the monomers.

  The polyvinyl acetal resin [B] is usually a resin having a repeating unit represented by Chemical Formula 1.

In Chemical Formula 1, n is a number (natural number) indicating the type of aldehyde used in the acetalization, R ₁ , R ₂ ,..., R _n are alkyl residues or hydrogen atoms of the aldehyde used in the acetalization reaction. _{, k (1), k (} 2), ···, k (n) each of R _1, R _2, ···, the proportion of acetal units containing R _n (mol ratio), l is the vinyl alcohol unit The ratio (mol ratio), m is the ratio (mol ratio) of vinyl acetate units. However, k ₍₁₎ + k ₍₂₎ + ... + k _(n) + l + m = 1, and k ₍₁₎ , k ₍₂₎ , ..., k _(n) , l, and m are any May be zero. The repeating units are not particularly limited by the arrangement order shown in Chemical Formula 1, and may be arranged at random, may be arranged in a block shape, or may be arranged in a taper shape.

  The polyvinyl acetal resin [B] used in the present invention can be obtained, for example, by reacting a polyvinyl alcohol resin and an aldehyde.

  The polyvinyl alcohol resin used for the production of the polyvinyl acetal resin [B] has a number average polymerization degree of 200 to 4,000, preferably 300 to 3,000, more preferably 500 to 2,000. . When the number average polymerization degree of the polyvinyl alcohol resin is less than 200, the mechanical properties of the obtained polyvinyl acetal resin are insufficient, and the mechanical properties, particularly toughness, of the acrylic resin film of the present invention tends to be insufficient. On the other hand, when the number average polymerization degree of the polyvinyl alcohol resin exceeds 4,000, the melt viscosity at the time of melt-kneading with the methacrylic resin tends to increase.

A polyvinyl alcohol resin is not specifically limited by the manufacturing method, For example, what was manufactured by saponifying polyvinyl acetate etc. with an alkali, an acid, ammonia water, etc. can be used.
The polyvinyl alcohol resin may be completely saponified, or may be a partially saponified partially saponified polyvinyl alcohol resin. It is preferable to use a saponification degree of 80 mol% or more.

As the polyvinyl alcohol resin, a copolymer of vinyl alcohol and a monomer copolymerizable therewith, such as an ethylene-vinyl alcohol copolymer resin and a partially saponified ethylene-vinyl alcohol copolymer resin, can be used. . Furthermore, a modified polyvinyl alcohol resin into which carboxylic acid or the like is partially introduced can be used.
These polyvinyl alcohol resins may be used individually by 1 type, and may be used in combination of 2 or more types.

  The aldehyde used for the production of the polyvinyl acetal resin [B] is not particularly limited. For example, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butyraldehyde, n-octylaldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, furfural, Glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde and the like can be mentioned. These aldehydes may be used alone or in combination of two or more. Of these aldehydes, those mainly composed of butyraldehyde are preferred.

The polyvinyl acetal resin [B] obtained by performing acetalization of the polyvinyl alcohol resin with an aldehyde mainly composed of butyraldehyde is particularly called polyvinyl butyral. In this invention, the polyvinyl butyral which the ratio (refer the following formula) of a butyral unit out of the acetal unit which exists in polyvinyl acetal resin [B] exceeds 0.9 is preferable. That is, in the structural formula of the polyvinyl acetal resin shown in Chemical Formula ₁ , when R ₁ = C ₃ H ₇ (alkyl residue of butyraldehyde), k ₍₁₎ / (k ₍₁₎ + k ₍₂₎ + -It is preferable that + k _(n) )> 0.9.

  The reaction between the polyvinyl alcohol resin and the aldehyde ((co) acetalization reaction) can be performed by a known method. For example, an aqueous medium method in which an aqueous solution of polyvinyl alcohol resin and an aldehyde are acetalized in the presence of an acid catalyst to precipitate resin particles; a polyvinyl alcohol resin is dispersed in an organic solvent, and an aldehyde Examples thereof include a solvent method in which an acetalization reaction is performed and the reaction solution is precipitated with water or the like which is a poor solvent for the polyvinyl acetal resin. Of these methods, the aqueous medium method is preferable.

  The acid catalyst is not particularly limited. For example, organic acids such as acetic acid and p-toluenesulfonic acid; inorganic acids such as nitric acid, sulfuric acid and hydrochloric acid; gas which shows acidity when an aqueous solution such as carbon dioxide gas is used; cation exchange And solid acid catalysts such as metal oxides and metal oxides.

The degree of acetalization of the polyvinyl acetal resin [B] is 55 to 83 mol%. By using a polyvinyl acetal resin having a degree of acetalization within this range, the acrylic resin film of the present invention can be obtained easily and at low cost by melt processing or production.
In addition, the acetalization degree (mol%) of polyvinyl acetal resin (B) can be defined by the following formula | equation.
Acetalization degree (mol%) =
{K ₍₁₎ + k ₍₂₎ + ... + k _(n) } × 2
/ {{K ₍₁₎ + k ₍₂₎ +... + K _(n) } × 2 + l + m} × 100

The degree of acetalization of the polyvinyl acetal resin is determined by titration of the mass proportion of vinyl alcohol units (l ₀ ) and the proportion of vinyl acetate units (m ₀ ) according to the method described in JIS K6728 (1977). The mass ratio (k ₀ ) of the unit is obtained by k ₀ = 1−l ₀ −m ₀ , and from this, the molar ratio (l) of vinyl alcohol units and the molar ratio (m) of vinyl acetate units are calculated, k = 1− The ratio of vinyl acetal units (k = k ₍₁₎ + k ₍₂₎ +... + k _(n) ) is calculated by the formula of 1−m, and the degree of acetalization (mol%) = {k ₍₁₎ + k ₍₂₎ + ... + k _(n) } × 2 / {{k ₍₁₎ + k ₍₂₎ + ... + k _(n) } × 2 + l + m} × 100, or polyvinyl acetal resin Deuterated dimethylsulfur Was dissolved in Okisaido may be calculated by measuring the ¹ H-MMR or ¹³ C-NMR,.

The ratio of acetalization with butyraldehyde is particularly called the degree of butyralization. In the structural formula of polyvinyl acetal shown in Chemical Formula ₁ , when R ₁ = C ₃ H ₇ (an alkyl residue of butyraldehyde), the degree of butyralization is defined by the following formula.
Butyral degree (mol%) = {k ₍₁₎ } × 2
/ {{K ₍₁₎ + k ₍₂₎ +... + K _(n) } × 2 + l + m} × 100

  More preferably, the polyvinyl acetal resin [B] used in the present invention has a butyralization degree of 55 to 75 mol%. When a polyvinyl acetal resin having a butyralization degree in the above range is used, it is excellent in mechanical properties, particularly toughness, and the acrylic resin film of the present invention can be obtained easily and inexpensively. Further, when a polyvinyl acetal resin having a butyralization degree in the above range is used, the difference between the refractive index of the methacrylic resin (A) and the refractive index of the polyvinyl butyral is reduced, and the transparent characteristic of the methacrylic resin (A) is obtained. (High visible light transmittance, low haze) is easily maintained. Furthermore, when stretched, bent, subjected to an impact, and / or placed in a wet and heat condition for a long time, the feature of hardly whitening is likely to appear.

  If the degree of butyralization is less than 55 mol%, the production cost of the polyvinyl acetal resin is high, the thermal stability is lowered, and the yellowness (YI) of the acrylic resin film of the present invention tends to increase. In addition, the compatibility with the methacrylic resin is lowered, the mechanical properties of the acrylic resin film of the present invention, particularly the toughness, is lowered, and the handleability of the film tends to be deteriorated. When the degree of butyralization exceeds 75 mol%, the compatibility with the methacrylic resin is lowered, the mechanical properties, particularly the toughness, of the acrylic resin film of the present invention tends to be lowered, and the handleability of the film tends to deteriorate. Further, the difference between the refractive index of the methacrylic resin [A] and the refractive index of the polyvinyl acetal resin [B] increases, and the transparency that is a feature of the methacrylic resin [A] tends to decrease.

  Moreover, suitable polyvinyl acetal resin [B] contains 17-45 mol% of vinyl alcohol units normally, and usually contains 0 mol% or more and 5 mol% or less of vinyl acetate units, Preferably it contains 0 mol% or more and 3 mol% or less.

The slurry produced in the aqueous medium method and the solvent method is usually acidic due to an acid catalyst. As a method for removing the acid catalyst, the slurry is repeatedly washed with water, and the pH is usually adjusted to 5 to 9, preferably 6 to 9, more preferably 6 to 8; a neutralizing agent is added to the slurry, The method of adjusting pH to 5-9 normally, Preferably 6-9, More preferably, 6-8; The method of adding alkylene oxides etc. are mentioned.
Examples of the compound used for removing the acid catalyst include alkali metal compounds such as sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, ammonia, and an aqueous ammonia solution. Examples of alkylene oxides include ethylene oxide, propylene oxide; glycidyl ethers such as ethylene glycol diglycidyl ether.

Next, salts generated by neutralization, aldehyde reaction residues, and the like are removed. The removal method is not particularly limited, and methods such as repeated dehydration and water washing are usually used.
The water-containing polyvinyl acetal resin from which residues and the like have been removed is dried as necessary, and further processed into powder, granules, or pellets as necessary, and used as a molding material. When processing into a powder form, a granule form, or a pellet form, it is preferable to reduce the reaction residue of aldehyde, moisture, etc. by deaeration in a reduced pressure state.

In the acrylic resin film of the present invention, at least two glass transition temperatures are observed in the dynamic viscoelasticity measurement. One is the glass transition temperature (Tg _AP ) attributed to the methacrylic resin (A), and the other is the glass transition temperature (Tg _BP ) attributed to the polyvinyl acetal resin (B).
When only one glass transition temperature can be observed, that is, when Tg _AP = Tg _BP , the methacrylic resin (A) and the polyvinyl acetal resin (B) in the acrylic resin film are in a completely compatible state. It shows that it has become.
When Tg _AP = Tg _A and Tg _BP = Tg _B , this indicates that the methacrylic resin (A) and the polyvinyl acetal resin (B) are in a completely incompatible state.
In contrast, the acrylic resin film of the present invention, the glass transition temperature Tg _AP due to methacrylic resin (A) is methacrylic resin (A) alone with a glass transition temperature (Tg _A) and the polyvinyl acetal resin is a value between the glass transition temperature (Tg _B) at (B) alone. That is, the relationship of Tg _B <Tg _AP <Tg _A or Tg _A <Tg _AP <Tg _B is satisfied. The acrylic resin film of the present invention having Tg _AP satisfying such a relationship is considered to be in a state where the methacrylic resin (A) and the polyvinyl acetal resin (B) are partially compatible. The acrylic resin film of the present invention is preferably such that at least the methacrylic resin (A) forms a continuous phase.
In the present invention, when the methacrylic resin (A) is a combination of two or more methacrylic resins, the glass transition temperature of any one of the combinations is Tg _A , and the polyvinyl acetal resin (B) is In the case of a combination of two or more polyvinyl acetal resins, the glass transition temperature of any one of the combinations is defined as Tg _B , and the above relationship, that is, Tg _B <Tg _AP <Tg _A or Tg _A <Tg _AP It is sufficient if the relationship <Tg _B is satisfied.

Although the detailed reason is not clear, when the methacrylic resin (A) and the polyvinyl acetal resin (B) are partially compatible, the acrylic resin film of the present invention has methacrylic heat resistance, surface hardness, and rigidity. It is almost the same as resin, and it is difficult to whiten when stretched, bent, subjected to impact, and / or placed under wet heat conditions for a long time. In addition, it has excellent toughness and handleability.
On the other hand, when the methacrylic resin (A) and the polyvinyl acetal resin (B) are completely compatible, the surface hardness of the acrylic resin film tends to decrease. Further, when the methacrylic resin (A) and the polyvinyl acetal resin (B) are completely compatible and Tg _B <Tg _A , the heat resistance tends to decrease. When the methacrylic resin (A) and the polyvinyl acetal resin (B) are completely incompatible, the strength decreases or whitens.

  In the acrylic resin film of the present invention, the mass ratio [A] / [B] of the methacrylic resin [A] and the polyvinyl acetal resin [B] is 99/1 to 51/49. From the viewpoint of toughness, that is, handleability and surface hardness of the acrylic resin film of the present invention, the mass ratio [A] / [B] is preferably 95/5 to 60/40, and 90/10 to 60/40. It is more preferable that

  When the proportion of the polyvinyl acetal resin [B] is less than 1% by mass, mechanical properties such as toughness of the acrylic resin film of the present invention tend to be lowered, and the handleability of the film tends to be deteriorated. On the other hand, when the proportion of the polyvinyl acetal resin [B] exceeds 49% by mass, the surface hardness of the acrylic resin film of the present invention tends to be insufficient.

  Various additives as necessary, for example, antioxidants, stabilizers, lubricants, processing aids, antistatic agents, antioxidants, colorants, impact resistance aids, foaming, are added to the acrylic resin film of the present invention. Agents, fillers, matting agents and the like may be added. In addition, it is preferable not to add a large amount of a softening agent or a plasticizer from the viewpoint of mechanical properties and surface hardness of the acrylic resin film of the present invention.

  It is preferable to add an ultraviolet absorber to the acrylic resin film of the present invention for the purpose of improving the weather resistance. Although the kind of ultraviolet absorber is not specifically limited, A benzotriazole type or a triazine type is preferable. The addition amount of the ultraviolet absorber is usually 0.1 to 10% by mass, preferably 0.3 to 5% by mass, based on the total mass of the methacrylic resin [A] and the polyvinyl acetal resin [B]. More preferably, it is 0.3-2 mass%.

  The additive added to the acrylic resin film of the present invention may be added to the methacrylic resin [A] and / or the polyvinyl acetal resin [B] before melt kneading, or the methacrylic resin [ A] and polyvinyl acetal resin [B] may be added during melt-kneading, or a composition containing methacrylic resin [A] and polyvinyl acetal resin [B] is prepared, and the composition is manufactured. You may add when forming a film. Alternatively, the acrylic resin film may be produced by mixing the methacrylic resin [A], the polyvinyl acetal resin [B], and the above additives and directly forming the film.

  In the acrylic resin film of the present invention, the methacrylic resin [A] preferably forms a continuous phase. When the methacrylic resin [A] forms a continuous phase, an acrylic resin film having good heat resistance and high surface hardness derived from the methacrylic resin [A] is obtained.

  The acrylic resin film of the present invention is not particularly limited by its production method, but the above-mentioned methacrylic resin [A] and polyvinyl acetal resin [B] are melted at the above mass ratio ([A] / [B]). It is preferable to obtain by a method of kneading and forming a film.

In particular, methacrylic resin [A] and polyvinyl acetal resin [B] are melt-kneaded at a resin temperature of 140 ° C. or higher while being sheared at a shear rate of 100 sec ⁻¹ or higher, and then cooled to a temperature of 120 ° C. or lower. It is preferable to include a process.
In a more preferred production method, when the methacrylic resin (A) and the polyvinyl acetal resin (B) are melt-kneaded at a resin temperature of 140 ° C. or higher, a shearing rate of 100 sec ⁻¹ or higher is applied, It is preferable that the step of setting the speed to 50 sec ⁻¹ or less is performed at least twice. Through such a process, an acrylic resin film in which at least the methacrylic resin (A) forms a continuous phase can be obtained.

If it is a manufacturing method including the above-mentioned process, once a methacrylic resin [A] and a polyvinyl acetal resin [B] are known kneading machines such as a single screw extruder, a twin screw extruder, a Banbury mixer, a brabender, an open roll, and a kneader. was used to melt-kneaded in the respective constituent shear rate 100 sec ^-1 or more shear applied while the resin temperature 140 ° C. or higher, preferably, applying a shear or shear rate 100 sec ^-1, the shear rate And at least twice each of the steps of 50 sec ^-1 or less, melt-kneaded at a resin temperature of 140 ° C or higher, then rapidly cooled to 120 ° C or lower, cut as necessary to form a pellet, Or a mixture containing a methacrylic resin [A] and a polyvinyl acetal resin [B]. While a cross-sectional speed 100 sec ^-1 or more shear, preferably, applying a shear or shear rate 100 sec ^-1, through at least 2 times each and the steps to the shear rate 50 sec ^-1 or less, the resin temperature It may be melted at 140 ° C. or higher, rapidly cooled to 120 ° C. or lower, and directly formed into a film shape.

  Among these production methods, a large shearing force is obtained, and the methacrylic resin [A] tends to form a continuous phase and is excellent in stability and handleability. Therefore, it is cooled after being melt-kneaded using a twin screw extruder. It is preferable to cut it as necessary to once form a pellet and to form the pellet into a film. The resin temperature at the time of melt kneading is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, and particularly preferably 180 ° C. or higher. Further, from the viewpoint of suppressing deterioration of the methacrylic resin [A] and the polyvinyl acetal resin [B], the resin temperature is preferably 300 ° C. or less, and more preferably 280 ° C. or less.

Shear which gives the time of melt-kneading is preferably a shear rate is 100 sec ^-1 or more, and particularly preferably 200 sec ^-1 or more. When producing pellets of the above mixture, when the resin temperature is melted at 140 ° C. or higher while applying a shear of 100 sec ⁻¹ or more and cooled to 120 ° C. or less, the shear is again 100 sec ⁻¹ or more at the time of film formation. It may be melted at a resin temperature of 140 ° C. or higher while applying, but this is not particularly necessary.

  The acrylic resin film of the present invention can be produced using a known method such as a T-die method, an inflation method, a melt casting method, or a calendar method. From the viewpoint that a film having good surface smoothness and low haze can be obtained, a method comprising a step of extruding the melt-kneaded material from a T-die in a molten state and bringing the both surfaces into contact with a mirror roll surface or a mirror belt surface and molding. Is preferred. The roll or belt used at this time is preferably made of metal. When forming the film by bringing both sides of the extruded melt-kneaded material into contact with a mirror surface, it is preferable to press and sandwich both surfaces of the film with a mirror roll or a mirror belt. The pinching pressure by the mirror roll or the mirror belt is preferably high, and the linear pressure is preferably 10 N / mm or more, and more preferably 30 N / mm or more.

  Further, from the viewpoint of obtaining a film having good surface smoothness, good surface gloss, and low haze, the mirror surface roll that sandwiches the film or the mirror surface roll that sandwiches the film at least one surface temperature of the mirror belt or 60 ° C. It is preferable that the surface temperature of both mirror belts is 130 ° C. or lower. When the surface temperature of both the mirror roll or mirror belt sandwiching the film is less than 60 ° C, the resulting acrylic resin film tends to lack surface smoothness and haze, and when at least one surface temperature exceeds 130 ° C Since the film and the mirror roll or mirror belt are too close together, the film surface tends to be rough when the film is peeled off from the mirror roll or mirror belt, and the surface smoothness of the resulting acrylic resin film is lowered or haze is reduced. It tends to be higher.

  The roughness of at least one surface of the acrylic resin film of the present invention is 1.5 nm or less, preferably 0.1 to 1.0 nm. This makes it easy to handle at the time of cutting, punching, etc., and when used for applications that require design, it is possible to have a surface gloss or a clear pattern layer printed on the acrylic resin film of the present invention. Excellent. Moreover, in optical use, it is excellent in optical characteristics such as light transmittance and in shaping accuracy when performing surface shaping. In addition, the roughness of a molded object (film) is the value calculated | required by the method as described in an Example.

  Further, the haze of the acrylic resin film of the present invention is preferably 0.3% or less, more preferably 0.2% or less at a thickness of 100 μm. This makes it easy to handle at the time of cutting, punching, etc., and when used for applications that require design, it is possible to have a surface gloss or a clear pattern layer printed on the acrylic resin film of the present invention. Excellent. Further, in optical applications such as a liquid crystal protective film and a light guide film, the use efficiency of the light source is preferably increased. Furthermore, it is preferable because it is excellent in shaping accuracy when performing surface shaping.

  The thickness of the acrylic resin film of the present invention is preferably 500 μm or less. If it is thicker than 500μm, the secondary processability such as laminating property, handling property, cutting property and punching property will deteriorate, making it difficult to use as a film and increasing the unit price per unit area, which is economically disadvantageous. This is not preferable. The thickness of the film is more preferably 50 to 300 μm, particularly preferably 75 to 200 μm.

  The acrylic resin film of the present invention may be colored. As a coloring method, the composition itself of the methacrylic resin [A] and the polyvinyl acetal resin [B] contains a pigment or a dye, and the resin itself before film formation is colored; the acrylic resin film is dyed Examples of the dyeing method include dipping in a liquid in which the powder is dispersed and coloring, but is not particularly limited thereto.

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

  The surface of the acrylic resin film of the present invention has a JIS pencil hardness (thickness: 100 μm), preferably HB or harder, more preferably F or harder, more preferably H or harder. Since the acrylic resin film of the present invention having a hard surface is difficult to be damaged, it is suitably used as a decorative and protective film for the surface of a molded product that requires design.

(Laminated film)
In the laminated film of the present invention, at least one other thermoplastic resin layer is provided on at least one surface of the above-mentioned acrylic resin film of the present invention, directly or via an adhesive layer. The laminated film of the present invention may be one in which a base material made of non-woody fibers such as a wooden base material or kenaf is provided on at least one surface of the above-mentioned acrylic resin film of the present invention.
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 resins, ABS (acrylonitrile-butadiene- Styrene copolymer) resin and the like.

The method for producing the laminated film is not particularly limited. For example, (1) Acrylic resin film of the present invention and another thermoplastic resin film are prepared separately and laminated continuously between heated rolls, a method of thermocompression bonding with a press, compressed air or vacuum A method of laminating at the same time as molding, a method of laminating through an adhesive layer (wet lamination); (2) Laminating another thermoplastic resin melt-extruded from a T die using the acrylic resin film of the present invention as a base material (3) A mixture of the methacrylic resin [A] and the polyvinyl acetal resin [B] described above and another thermoplastic resin are coextruded to form a layer of the acrylic resin film of the present invention. The method of obtaining the film by which the layer of the other thermoplastic resin film was laminated | stacked, etc. are mentioned.
Among these methods, in the method (1) or (2), surface treatment such as corona treatment is applied to the bonding surface side of the acrylic resin film or other thermoplastic resin film of the present invention before lamination. Also good.

  In the laminated film of the present invention, the acrylic resin film of the present invention may be used for the inner layer or a part of the laminated film, or may be used for the outermost layer. There is no particular limitation on the number of laminated films. The other resin used for the laminated film is preferably a transparent resin such as a methacrylic resin from the viewpoint of the design of the film. From the viewpoint that the film is not easily scratched and the design properties last for a long time, the outermost layer preferably has a high surface hardness and weather resistance. For example, a film made of a methacrylic resin or the acrylic thermoplastic resin film of the present invention Is preferred.

  The laminate of the present invention is obtained by providing the acrylic resin film of the present invention or the laminate film of the present invention on the surface of another thermoplastic resin and / or thermosetting resin.

  Other thermoplastic resins used in the laminate include polycarbonate resin, polyethylene terephthalate resin, polyamide resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, other (meth) acrylic resins, ABS (acrylonitrile- Butadiene-styrene copolymer) resin. Examples of other thermosetting resins include epoxy resins, phenol resins, and melamine resins. Further, the laminate of the present invention may be one in which the acrylic resin film of the present invention or the laminate film of the present invention is provided on the surface of a substrate made of non-woody fibers such as a wooden substrate or kenaf. Good.

  The method for producing the laminate of the present invention is not particularly limited. For example, the acrylic resin film of the present invention or the laminated film of the present invention is heated under vacuum on the surface of another thermoplastic resin and / or thermosetting resin or on the surface of a wooden substrate or a non-wood fiber substrate. The laminate of the present invention can be obtained by molding, pressure forming, and compression molding. In the laminate of the present invention, the acrylic resin film of the present invention or the laminate film of the present invention is provided on the outermost layer of a molded product or a base material, thereby being excellent in surface smoothness, surface hardness, gloss, etc. In addition, the pattern printed on the acrylic resin film is clearly displayed.

Among the methods for producing the laminate of the present invention, a preferred method is a method generally called an injection molding simultaneous bonding method.
In this simultaneous injection molding method, the acrylic resin film of the present invention or the laminated film of the present invention is inserted between male and female molds for injection molding, and a thermoplastic resin melted from one side of the film is inserted into the mold. Injecting to form an injection-molded body, and simultaneously bonding the film to the molded body.

The film to be inserted into the mold may be a flat film as it is, or may be preliminarily formed into a concavo-convex shape by vacuum forming, pressure forming or the like.
The preforming of the film may be performed by a separate molding machine, or may be preformed in a mold of an injection molding machine used for the injection molding simultaneous bonding method. The latter method, that is, a method in which a film is preformed and then a molten resin is injected on one side thereof is called an insert molding method.
When the laminated film of the present invention is used for the film, the laminated other thermoplastic resin layer is on the resin side to be injection-molded, that is, the acrylic resin film of the present invention is the outermost surface. It is preferable to arrange in. Thus, the laminated body by which the acrylic resin film of this invention was provided in the outermost layer can be obtained.

  The acrylic resin film or laminated film of the present invention utilizes a good handleability, a good surface smoothness and a high surface hardness, and a molded product requiring a design property or a high optical property, In other words, billboard parts such as advertising tower, stand signboard, sleeve signboard, bamboard signboard, rooftop signboard; display parts such as showcase, partition plate, store display; fluorescent lamp cover, mood lighting cover, lamp shade, light ceiling, light wall Lighting parts such as chandeliers; Interior parts such as furniture, pendants, mirrors, etc .; Building parts such as doors, domes, safety window glass, partitions, staircases, balconies, roofs of leisure buildings; aircraft windshields, pilots Visor, motorcycle, motor boat windshield, bus shading plate, automotive side visor, rear visor, head wheel Transportation equipment-related parts such as automotive exterior parts such as automotive headlight covers, automobile interior parts, bumpers, etc .; audio equipment nameplates, stereo covers, TV protective masks, vending machines, mobile phones, personal computers, etc .; childcare Medical equipment parts such as instruments and X-ray parts; equipment-related parts such as machine covers, instrument covers, experimental devices, rulers, dials, observation windows; traffic-related parts such as road signs, guide plates, curved mirrors, sound barriers; etc. , Greenhouses, large aquariums, box aquariums, bathroom components, clock panels, bathtubs, sanitary, desk mats, game parts, toys, face decoration masks and protective films for welding, wallpaper, marking films; LCD protective film, light guide film, Fresnel lens, lenticular lens, front film of various displays, diffusion film, etc. It is suitably used in optical related parts, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “part” represents “part by mass” unless otherwise specified, and “%” represents “% by mass” unless otherwise specified.

Physical properties of methacrylic resins, polyvinyl acetal resins, thermoplastic resin compositions, films, etc. were evaluated according to the following methods.
(1) Weight average molecular weight Using tetrahydrofuran as a solvent, Shodex (trademark) GPC SYSTEM11 manufactured by Showa Denko KK was connected to Shodex (trademark) KF-806L as a column for gel permeation chromatography, and Shodex (trademark) as a detector. It measured using the differential refractive index detector RI-101. The sample solution was prepared by accurately weighing 3 mg of resin, dissolving it in 3 ml of tetrahydrofuran, and filtering the solution through a 0.45 μm membrane filter. The flow rate during measurement was 1.0 ml / min. The weight average molecular weight (Mw) was calculated as the molecular weight in terms of polymethyl methacrylate based on a calibration curve prepared with standard polymethyl methacrylate manufactured by Polymer Laboratories.

(2) Glass transition temperature (Tg)
The peak temperature (Tg) of the main dispersion of loss tangent (tan δ) was obtained by injection-molding a pellet made of an acrylic resin composition used for producing a film using EXSTAR6000 DMS manufactured by SII Nanotechnology Co., Ltd. A rectangular parallelepiped test piece having a length of 60 mm, a width of 10 mm, and a thickness of 4 mm obtained by cutting the test piece obtained in the above-described manner in a bending mode (both-supported beam measurement) has a sinusoidal vibration of 10 Hz and a heating rate of 3 ° C./min. . It was measured by.

(3) Measurement of film surface roughness Using an atomic force microscope (SPI4000 probe station E-sweep environment control unit manufactured by SII Nano Technology), the surface shape was measured in DFM mode. SI-DF20 (back Al) manufactured by SII Nano Technology was used as the probe. Prior to the sample measurement, a reference sample having a pitch of 10 μm and a step of 100 nm is measured. The measurement error of the X axis and Y axis of the apparatus is 5% or less with respect to 10 μm, and the error of the Z axis is 5% or less with respect to 100 nm. It was confirmed.

The observation area of the sample was 2 μm × 2 μm, and the measurement frequency was 1.0 Hz. The number of scan lines was 512 on the X axis and 512 on the Y axis. The measurement was performed in an atmospheric environment at 25 ° C. ± 2 ° C. and humidity 30 ± 5%. The obtained measurement data was analyzed by data processing software attached to the apparatus, and the average surface roughness Ra was obtained. In other words, after selecting the [Third-order tilt correction] command in the [Tool] menu of the measurement software of the device and correcting the entire tilt of the film and large waviness, the [Surface roughness analysis] command in the [Analysis] menu The average surface roughness Ra was selected. The average surface roughness Ra is defined as follows.
* Average surface roughness Ra: A value obtained by averaging the absolute values of deviations from the reference surface to the specified surface.

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 a 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。

S ₀ represents the area of the measurement region.

This average surface roughness Ra was measured at 10 different regions on both sides of the film (for convenience, the A surface and the B surface), and the average value of the 10 average surface roughness Ra was defined as the roughness of the film surface. .
The cubic inclination correction was performed by fitting the measured sample surface with a cubic surface by least square approximation to eliminate the influence of the inclination and waviness of the film sample.

(4) Measurement of film haze The haze of a film having a thickness of 100 μm was measured according to JIS K7136.

(5) Surface hardness of film The pencil hardness of a film having a thickness of 100 μm was measured according to JIS K5400.

(6) Handleability of film [A] Simultaneous film-forming trimming property Before extruding a film-like molded product from a T-die having a width of 500 mm using a GT-40 single-screw extruder manufactured by Plastics Engineering Laboratory, and winding the film In addition, a feather S Seikan single blade (product number FAS-10) manufactured by Feather Co., Ltd. is brought into contact with 5 cm from both ends of the film in parallel with the MD direction of the film and at an angle of 60 ° with respect to the film surface direction. Trimming was performed to evaluate the simultaneous trimming property of the film formation. The case where the film can be cut linearly and no cracks occurred in the MD direction of the film for more than 2 hours. The film can be cut linearly, but the cracks occurred once in the MD direction of the film within 2 hours. The case was evaluated as Δ, and the case where the film could not be cut linearly was evaluated as ×.

[B] Cutability of film A dumbbell super dumbbell cutter is attached to a dumbbell SDL-200 lever type sample cutter, and the film is placed on a dumbbell mount (size: 160 mm x 200 mm x 3 mm). Then, when the 1A type dumbbell-shaped test piece described in JIS K7162 is punched 10 times from the film, the case where cracks did not enter 10 times other than the 1A type dumbbell shape. The case where cracks occurred more than once was evaluated as Δ, and the case where cracks occurred all 10 times other than the 1A type dumbbell shape was evaluated as x.

(7) Surface Gloss of Film According to JIS K7105, 60 degree surface gloss of a film having a thickness of 100 μm was measured.

[Methacrylic resin]
A methacrylic resin composed of methyl methacrylate units and methyl acrylate units in the ratios shown in Table 1 was prepared by bulk polymerization. Table 1 shows the weight average molecular weight (Mw) and glass transition temperature (Tg _A ) of the prepared methacrylic resin.

[Polyvinyl acetal resin]
An aldehyde compound and an acid catalyst (hydrochloric acid) were added to an aqueous solution in which the polyvinyl alcohol resin was dissolved, and the mixture was stirred to acetalize to precipitate the resin. Washed to pH = 6 according to known methods, then suspended in alkaline aqueous medium and worked up with stirring, washed again to pH = 7, volatiles to 1.0% The polyvinyl acetal resin shown in Table 2 was obtained by drying until it became.

The degree of acetalization of the polyvinyl acetal resin was determined by the following procedure.
First, in accordance with the method described in JIS K6728 (1977), the mass ratio (l ₀ ) of the vinyl alcohol unit and the mass ratio (m ₀ ) of the vinyl acetate unit were determined by the methods described below. The mass ratio (k ₀ ) was determined by k ₀ = 1−l ₀ −m ₀ .
_{Then, l = (l 0 /44.1)/(l 0} /44.1+m 0 /86.1+2k 0 / Mw (acetal)) and _{m = (m 0 /86.1)/(l 0/} 44 .1 + m ₀ /86.1+2k ₀ / Mw (acetal)) by calculation, and the ratio of vinyl acetal units (k = k ₍₁₎ + k ₍₂₎ +... + K _(n) ), and finally the degree of acetalization (mol%) = {k ₍₁₎ + k ₍₂₎ +... + K _(n) } × 2 / {{k ₍₁₎ + k _{(2 )} +... + K _(n) } × 2 + l + m} × 100.
Here, Mw (acetal) is the molecular weight per acetalization unit. For example, in the case of polyvinyl butyral, Mw (acetal) = Mw (butyral) = 142.2.
In the case of coacetalization with butyraldehyde and other aldehydes, ¹ H-NMR or ¹³ C-NMR can be measured, and the degree of acetalization (mol%) can be calculated.

[How to find l ₀ and m ₀ ]
About 0.4 g of polyvinyl acetal resin is accurately weighed into a conical Erlenmeyer flask, dissolved by adding 10 ml of a mixed solution of pyridine / acetic anhydride (volume ratio 92/8) with a pipette, and attached with a cooler at a temperature of 50 ° C. On a water bath for 120 minutes. After cooling, 20 ml of dichloroethane was added and shaken well. Further, 50 ml of water was added, stoppered and shaken vigorously, and allowed to stand for 30 minutes. The acetic acid produced is titrated with N / 2 sodium hydroxide solution with phenolphthalein as an indicator until it turns pale red, and the titration is defined as a (ml). Separately, a blank test was performed, and the titration amount of the N / 2 sodium hydroxide solution required for this was defined as b (ml), and obtained by the following formula.
l ₀ = 2.2 × (ba) × F _l / (s _l × P _l )
In the formula, s _{1 is} the mass of the polyvinyl acetal resin, P ₁ is the pure content (%), and F ₁ is the titer of the N / 2 sodium hydroxide solution.
Also, weigh accurately about 0.4 g of polyvinyl acetal resin in a conical flask with a stirrup, add 25 ml of ethanol and dissolve at 85 ° C., add 5 ml of N / 10 sodium hydroxide solution while shaking well with a pipette, and cool. The vessel was attached and refluxed in a water bath at a temperature of 85 ° C. for 60 minutes. After cooling, 5 ml of N / 10 hydrochloric acid was added with a pipette, shaken well, and allowed to stand for 30 minutes. Excess hydrochloric acid was titrated with a N / 10 sodium hydroxide solution using phenolphthalein as an indicator until a slight red color was obtained, and the titer was c (ml). Separately, a blank test was carried out, and the titration amount of the N / 10 sodium hydroxide solution required for this was determined as d (ml), and obtained by the following formula.
m ₀ = 0.86 × (cd) × F _m / (s _m × P _m )
In the formula, s _{m is} the mass of the polyvinyl acetal resin, P _m is the pure content (%), and F _m is the titer of the N / 10 sodium hydroxide solution.

Example 1
A cylinder temperature of 220 ° C. using 75 parts of methacrylic resin (A-1) and 25 parts of polyvinyl acetal resin (B-1) using a twin screw kneading extruder TEX-44α (L / D = 40) manufactured by Nippon Steel. The mixture was kneaded at a screw rotation speed of 200 rpm to obtain thermoplastic resin composition pellets. The resin temperature measured just before the die of the extruder at that time was 233 ° C. Maximum shear rate of the extruder is 300 sec ^-1, shear rates in the clearance large portion of the barrel and the screw elements were 45 sec ^-1. Screw, the rotational speed of the used was a structure in which the shear shear and 45 sec ^-1 of 300 sec ^-1 is applied twice alternately.
The pellets of the obtained thermoplastic resin composition were injection-molded at a cylinder temperature of 240 ° C. using J50E2 manufactured by Nippon Steel Works to obtain a rectangular parallelepiped test piece having a length of 80 mm × width of 10 mm × thickness of 4 mm. Furthermore, by cutting the rectangular parallelepiped test piece, to obtain a rectangular test piece of length 60 mm × width 10 mm × thickness 4 mm, it was measured Tg _AP.
The pellet is extruded from a 500 mm wide T-die using GT-40 manufactured by Plastics Engineering Laboratory, and sandwiched between two metal mirror rolls adjusted to 90 ° C. directly below the T die at a pressing pressure of 50 N / mm. As a result, a film having a thickness of 100 μm was obtained. Table 3 shows the roughness of the surface of this film (for convenience, it was described as A and B surfaces, hereinafter the same), haze, surface hardness, handleability, and surface gloss.

Example 2
Pellets and rectangular parallelepiped test pieces / films were obtained in the same manner as in Example 1 except that the formulation was changed to 75 parts of methacrylic resin (A-2) and 25 parts of polyvinyl acetal resin (B-1). Table 3 shows Tg _AP , surface roughness of the film (for convenience, it was described as A and B surfaces, the same applies hereinafter), haze, surface hardness, handleability, and surface gloss.

Example 3
Pellets and rectangular parallelepiped test pieces / films were obtained in the same manner as in Example 1 except that the formulation was changed to 75 parts of methacrylic resin (A-3) and 25 parts of polyvinyl acetal resin (B-1). Table 3 shows Tg _AP , surface roughness of the film (for convenience, it was described as A and B surfaces, the same applies hereinafter), haze, surface hardness, handleability, and surface gloss.

Example 4
Just as in Example 1, except that the film is not sandwiched between two metal mirror rolls directly under the T die, and the film is brought into contact with only one mirror metal roll whose temperature is adjusted to 90 ° C., and one side is opened to the air. A film having a thickness of 100 μm was obtained. Table 3 shows Tg _AP , film surface roughness, haze, surface hardness, handleability, and surface gloss.

Examples 5-8
A film having a thickness of 100 μm was obtained in the same manner as in Example 4 except that the type of methacrylic resin and / or polyvinyl acetal resin was changed to the formulation described in Table 3. Table 3 shows Tg _AP , film surface roughness, haze, surface hardness, handleability, and surface gloss.

Comparative Example 1
Two metal mirror surfaces that were extruded from a 500 mm wide T-die using GT-40 manufactured by Plastics Engineering Laboratory using only methacrylic resin (A-1), and the temperature was adjusted to 90 ° C. immediately below the T-die. A film having a thickness of 100 μm was obtained by sandwiching with a roll at a pressing pressure of 50 N / mm. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

Comparative Example 2
A film having a thickness of 100 μm was obtained in the same manner as in Comparative Example 1 except that only the methacrylic resin (A-2) was used. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

Comparative Example 3
An attempt was made to produce a film in the same manner as in Comparative Example 1 except that only the methacrylic resin (A-3) was used, but a film-like molded product could not be produced because the resin was very brittle. .

Comparative Example 4
In accordance with Example 1 of JP-B-55-27576 (= USP 3793402), the innermost layer is a crosslinked polymer polymerized using methyl methacrylate and a small amount of allyl methacrylate, and the intermediate layer is mainly composed of butyl acrylate. Further, a soft elastic copolymer polymerized using styrene and allyl methacrylate, and a spherical polymer having an average particle diameter of 280 nm consisting of a hard polymer polymerized using methyl methacrylate and a small amount of ethyl acrylate as the outermost layer The core-shell type particle (C-1) having a three-layer structure was prepared, and 25 parts of the core-shell type particle having the three-layer structure was mixed with 75 parts of a methacrylic resin (A-1). Pellets were obtained by kneading using a twin-screw kneading extruder TEX-44α (L / D = 40). The obtained pellets were extruded from a T-die having a width of 500 mm using GT-40 manufactured by Plastics Engineering Laboratory, and the pressure was adjusted to 50 N / mm with two metal mirror rolls adjusted to 90 ° C. immediately below the T-die. The film having a thickness of 100 μm was obtained. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

Comparative Example 5
In Comparative Example 4, a soft elastic copolymer in which the inner layer was polymerized using butyl acrylate as a main component and further using styrene and allyl methacrylate without forming the innermost layer of the core-shell type particles having a three-layer structure The core-shell type particles (C-2) having a spherical two-layer structure with an average particle size of 280 nm, which is made of a hard polymer whose outer layer is polymerized using methyl methacrylate and a small amount of ethyl acrylate, 25 parts of core-shell type particles having a two-layer structure are mixed with 75 parts of methacrylic resin (A-1) and kneaded using a twin screw kneading extruder TEX-44α (L / D = 40) manufactured by Nippon Steel. To obtain a pellet. The obtained pellets were extruded from a T-die having a width of 500 mm using GT-40 manufactured by Plastics Engineering Laboratory, and the pressure was adjusted to 50 N / mm with two metal mirror rolls adjusted to 90 ° C. immediately below the T-die. The film having a thickness of 100 μm was obtained. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

Comparative Example 6
In Comparative Example 4, the film was formed in a state in which the film was brought into contact with only one mirror surface metal roll whose temperature was adjusted to 90 ° C. and one side was opened to the air without being sandwiched between the two metal mirror surface rolls immediately below the T die. Except for this, a film having a thickness of 100 μm was obtained in the same manner as in Comparative Example 4. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

Comparative Example 7
In Comparative Example 5, the film was formed in a state in which the film was brought into contact with only one mirror surface metal roll whose temperature was adjusted to 90 ° C. and one side was opened to the air without being sandwiched between the two metal mirror surface rolls immediately below the T die. Except this, a film having a thickness of 100 μm was obtained in the same manner as in Comparative Example 5. Table 4 shows the roughness, haze, surface hardness, handleability, and surface gloss of the film.

  As shown in Table 3 and Table 4, in the films of Comparative Examples 4 and 5 using the core-shell particles, the roughness was about 2.7 nm on both sides on average even though both sides were brought into contact with the mirror roll. High and low gloss. On the other hand, the film of the example according to the present invention has a very low roughness of about 0.9 mm on both sides in average when both sides are brought into contact with a mirror roll. Furthermore, the surface gloss is high and the haze is also small. From these things, the acrylic resin film of the present invention has the same surface smoothness and haze as a film made of only a methacrylic resin, and film-forming simultaneous trimming properties that could not be achieved only with a methacrylic resin, It was found that the film has improved handling properties such as cutting ability and achieved an unprecedented balance.

Claims (15)

A methacrylic resin [A] containing 80 to 99.9% by weight of methyl methacrylate units and 0.1 to 20% by weight of alkyl acrylate units and having a weight average molecular weight of 40,000 or more;
A mass ratio ([A] / [B]) of polyvinyl acetal resin [B] having a degree of acetalization of 55 to 83 mol% obtained by (co) acetalizing a polyvinyl alcohol resin having a number average polymerization degree of 200 to 4000 ) 99/1 to 51/49,
The glass transition temperature Tg _AP due to methacrylic resin (A) between the glass transition temperature Tg _B in the polyvinyl acetal resin (B) alone and a glass transition temperature Tg _A in the methacrylic resin (A) alone An acrylic resin film having at least one surface with a roughness of 1.5 nm or less.   The acrylic resin film according to claim 1, wherein the haze measured according to JIS K7136 is 0.3% or less.   The acrylic resin film according to claim 1 or 2, which has a pencil hardness of HB or higher.   The methacrylic resin [A] and the polyvinyl acetal resin [B] are melt-kneaded, extruded in a molten state from a T die, and formed by bringing both surfaces into contact with a mirror roll surface or a mirror belt surface. The acrylic resin film in any one of -3.   The acrylic resin film according to any one of claims 1 to 4, wherein at least one side is printed. A methacrylic resin [A] containing 80 to 99.9% by weight of methyl methacrylate units and 0.1 to 20% by weight of alkyl acrylate units and having a weight average molecular weight of 40000 or more, and polyvinyl having a number average degree of polymerization of 200 to 4000 A polyvinyl acetal resin [B] having a degree of acetalization of 55 to 83 mol% obtained by (co) acetalizing an alcohol resin at a mass ratio ([A] / [B]) 99/1 to 51/49, The method for producing an acrylic resin film according to claim 1, comprising a step of melt-kneading at a resin temperature of 140 ° C. or higher while applying shear at a shear rate of 100 sec ⁻¹ or higher, and then cooling to a temperature of 120 ° C. or lower. When melt-kneaded at a resin temperature of 140 ° C. or higher, applying a shear or shear rate 100 sec ^-1, undergoes each at least twice a step of the shear rate to 50 sec ^-1 or less, according to claim 6 A method for producing an acrylic resin film. A methacrylic resin [A] containing 80 to 99.9% by weight of methyl methacrylate units and 0.1 to 20% by weight of alkyl acrylate units and having a weight average molecular weight of 40000 or more, and polyvinyl having a number average degree of polymerization of 200 to 4000 A polyvinyl acetal resin [B] having a degree of acetalization of 55 to 83 mol% obtained by (co) acetalizing an alcohol resin was melted at a mass ratio ([A] / [B]) 99/1 to 51/49. by kneading, the glass transition attributable to the methacrylic resin (a) between the glass transition temperature Tg _B of the glass transition temperature Tg _a in the methacrylic resin (a) alone the polyvinyl acetal resin (B) alone Obtaining a resin composition having a temperature Tg _AP ;
A method for producing an acrylic resin film, comprising a step of extruding the resin composition in a molten state from a T-die and bringing both surfaces into contact with a mirror roll surface or a mirror belt surface.
  The laminated body in which the film in any one of Claims 1-5 is provided in the surface of a thermoplastic resin and / or a thermosetting resin. Inserting the film according to any one of claims 1 to 5 between injection molding male and female molds,
The manufacturing method of a laminated body including the process of inject | pouring a thermoplastic resin from the one side of this film in this metal mold | die.   The laminated body obtained by the manufacturing method of Claim 10.   A laminated film in which at least one other thermoplastic resin layer is provided on at least one surface of the film according to claim 1.   A laminate comprising the laminated film according to claim 12 provided on a surface of a thermoplastic resin and / or a thermosetting resin. Inserting the laminated film according to claim 12 between injection molding male and female molds,
The manufacturing method of a laminated body including the process of inject | pouring a thermoplastic resin from the one side of this laminated | multilayer film in this metal mold | die.   The laminated body obtained by the manufacturing method of Claim 14.