JP2021055100A - Methacrylic resin composition - Google Patents

Abstract

To provide a methacrylic resin composition low in haze and excellent in ductility, film production property and stress whitening resistance, and a film.SOLUTION: A methacrylic resin composition formed by containing 1 to 45 pts.mass of a thermoplastic resin made of 60 mass% or larger of a structural unit derived from methyl methacrylate and 40 mass% or smaller of a structural unit derived from a mono-functional monomer other than methyl methacrylate, and 100 pts.mass of an acrylic multilayered polymer made of an outer layer made of a thermoplastic polymer (III), an intermediate layer made of a crosslinked rubber polymer (II) and a layer made of a crosslinked elastic body (I) and covered by contacting with the outer layer having an inner layer covered by contacting with the intermediate layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a methacrylic resin composition. More specifically, the present invention relates to a methacrylic resin composition having a low haze and excellent ductility, film forming property and stress whitening property.

In order to adjust the characteristics of the methacrylic resin, a technique using an acrylic crosslinked rubber polymer or the like is known.
For example, in Patent Document 1, a part of the methacrylic acid ester-based copolymer is grafted on acrylic acid ester-based crosslinked elastic particles, and the reduced viscosity of the methyl ethyl ketone-soluble component is 0.2 to 0.8 dl / g. A certain methacrylic resin composition is disclosed.

Patent Document 2 describes an acrylic graft copolymer obtained by graft-polymerizing a monomer component containing a methacrylic acid ester to an acrylic acid ester-based rubber-like polymer and a methacrylic-based weight containing 80% by mass or more of a methyl methacrylate unit. A resin composition comprising a coalescence and having a reduced viscosity of a soluble component of methyl ethyl ketone of 0.2 to 0.8 dl / g is disclosed.

Patent Document 3 describes methyl methacrylate 80 to 99.95% by mass, an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms 0 to 19.95% by mass, and a crosslinkable monomer 0.05. A core containing a polymer (III) obtained by polymerizing ~ 2% by mass, an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, 80 to 98% by mass, and a single amount of aromatic vinyl. An inner shell containing a crosslinked rubber polymer (I) obtained by polymerizing 1 to 19% by mass of a body and 1 to 5% by mass of a crosslinkable monomer, and 80 to 100% by mass of methyl methacrylate and the number of carbon atoms. It is a three-layer polymer particle composed of an outer shell containing a thermoplastic polymer (II) obtained by polymerizing 0 to 20% by mass of an acrylic acid alkyl ester monomer having an alkyl group of 1 to 8. A resin composition containing a crosslinked rubber particle component is disclosed.

In Patent Document 4, a monomer containing a methacrylic acid alkyl ester as a main component is graft-polymerized in the presence of an innermost layer polymer having a structure of one layer or two or more layers obtained by using an acrylic acid alkyl ester as a main component. A rubber-containing polymer having a multilayer structure of two or more layers having a weight average particle diameter of 0.01 to 0.5 μm, which is formed by molding an outermost layer polymer having a structure of one layer or two or more layers, is a constituent component. The acrylic resin composition is disclosed.

Such blending of the acrylic crosslinked rubber polymer with the methacrylic resin may bring about an improvement in ductility, a decrease in hardness, a decrease in film forming property, and the like.

Japanese Unexamined Patent Publication No. 2003-128734 Japanese Unexamined Patent Publication No. 2004-137298 Japanese Unexamined Patent Publication No. 2016-186081 Japanese Unexamined Patent Publication No. 2006-143785 Japanese Unexamined Patent Publication No. 2001-81270 Japanese Unexamined Patent Publication No. 11-335511 Japanese Unexamined Patent Publication No. 2004-352837 Japanese Unexamined Patent Publication No. 2002-361712

An object of the present invention is to provide a methacrylic resin composition and a film having low haze and excellent ductility, film forming property and stress whitening property.

In order to achieve the above object, the present invention including the following aspects has been completed.

[1] 1 to 45 parts by mass of a thermoplastic resin consisting of 60% by mass or more of a structural unit derived from methyl methacrylate and 40% by mass or less of a structural unit derived from a monofunctional monomer other than methyl methacrylate, and a thermoplastic weight. A methacrylic resin composition containing an outer layer made of coalesced (III) and 100 parts by mass of an acrylic multilayer polymer composed of a layer of a crosslinked elastic body covered in contact with the outer layer.
The crosslinked elastic layer has an intermediate layer made of the crosslinked rubber polymer (II) and an inner layer made of the crosslinked polymer (I) and covered in contact with the intermediate layer.
The crosslinked polymer (I) has a structural unit of 40 to 98.5% by mass derived from methyl methacrylate, a structural unit of 1 to 59.5% by mass derived from a monofunctional monomer other than methyl methacrylate, and polyfunctionality. The structural unit derived from the monomer consists of 0.05 to 0.4% by mass.
The crosslinked rubber polymer (II) has a structural unit derived from an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and / or a structural unit derived from a conjugated diene of 98.3 to 99% by mass, and a polyfunctional unit. It consists of structural units 1 to 1.7% by mass derived from the polymer.
The thermoplastic polymer (III) has a structural unit of 80 to 100% by mass derived from a methacrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and a structure derived from a monofunctional monomer other than the methacrylic acid alkyl ester. The unit consists of 0 to 20% by mass,
The total mass of the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) and the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) is the crosslinked polymer (I) and the crosslinked. The mass of the acetone-soluble component contained in the methacrylic resin composition is y mass% with respect to the mass of the methacrylic resin composition, which is x mass% with respect to the total mass of the rubber polymer (II), and the crosslinked elastic material. When the average diameter of the layer is d nanometer, the value calculated by the formula: x · d / y is 1.0 or more and 3.0 or less.
Methacrylic resin composition.

[2] The methacrylic resin composition according to [1], wherein the acetone-soluble component contained in the methacrylic resin composition has a ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of 2.3 to 3.0. Stuff.
[3] The ratio of the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (I) is 0. The methacrylic resin composition according to [1] or [2], which is 05 to 0.25.
[4] The methacrylic resin composition according to any one of [1] to [3], wherein the amount of the thermoplastic resin is 5 to 40 parts by mass with respect to 100 parts by mass of the acrylic multilayer polymer.

[5] The methacrylic resin composition according to any one of [1] to [4], wherein the acrylic multilayer polymer has a graft ratio of 33 to 50% by mass.
[6] The methacrylic resin composition according to any one of [1] to [5], wherein the amount of the crosslinked elastic body in the methacrylic resin composition is 20 to 40% by mass and d is 60 to 110. ..
[7] A film comprising the methacrylic resin composition according to any one of the above [1] to [6].

The methacrylic resin composition of the present invention has a low haze and is excellent in ductility, film forming property and stress whitening resistance. The methacrylic resin composition of the present invention is suitable as a molding material for electrical parts, vehicle parts, optical parts, ornaments, signboards, building materials and the like. The film of the present invention has excellent thickness uniformity and excellent stackability on other members. The film of the present invention is excellent in flexibility and does not whiten even when it is bent, for example, after being laminated with a vinyl chloride film.

Although the reason why the methacrylic resin composition of the present invention exerts the above-mentioned effects is not clear, the crosslinked polymer (I) suppresses the deformation of the crosslinked rubber polymer (II) during melt flow or plastic deformation. Therefore, it is presumed that the stress whitening in the methacrylic resin composition is suppressed. Further, it is presumed that the crosslinked polymer (I) contributes to the improvement of the melt moldability of the methacrylic resin composition by suppressing gelation. By controlling the flexibility of the crosslinked polymer (I) and the crosslinked rubber polymer (II) by the amount of polyfunctional monomer, etc., it contributes to the improvement of ductility, folding resistance, and tear strength of the methacrylic resin composition. presume.

It is a figure which shows an example of the electron micrograph of the methacrylic resin composition of this invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments.

The methacrylic resin composition of the present invention contains an acrylic multilayer polymer and a thermoplastic resin.

The acrylic multilayer polymer used in the present invention comprises an outer layer made of a thermoplastic polymer (III) and a layer of a crosslinked elastic body covered in contact with the outer layer.

The thermoplastic polymer (III) is a structural unit derived from a methacrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and, if necessary, a structural unit derived from a monofunctional monomer other than the methacrylic acid alkyl ester. It is a polymer composed of. The thermoplastic polymer (III) preferably does not contain structural units derived from the polyfunctional monomer.

The amount of the structural unit derived from the methacrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms constituting the thermoplastic polymer (III) is 80 to 100 mass with respect to the mass of the thermoplastic polymer (III). %, Preferably 85-95% by mass.

Examples of the methacrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (hereinafter, may be referred to as methacrylic acid C1-8 alkyl ester) include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2 methacrylic acid. -Ethylhexyl, propyl methacrylate, cyclohexyl methacrylate and the like can be mentioned. Of these, methyl methacrylate is preferable.

The amount of the structural unit derived from the monofunctional monomer other than the methacrylic acid C1-8 alkyl ester constituting the thermoplastic polymer (III) is 0 to 20 mass with respect to the mass of the thermoplastic polymer (III). %, preferably 5 to 15% by mass.
Examples of the monofunctional monomer other than the methacrylic acid C1-8 alkyl ester include acrylate esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and propyl acrylate; styrene and p-methylstyrene. , Α-Methylstyrene and other aromatic vinyl compounds; examples include maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide and NO-chlorophenylmaleimide.

The outer layer may be a single layer made of one type of thermoplastic polymer (III), or may be a multi-layer made of two or more types of thermoplastic polymer (III).

The amount of the thermoplastic polymer (III) is preferably 40 to 75% by mass, more preferably 50 to 70% by mass, and further preferably 55 to 65% by mass with respect to the mass of the acrylic multilayer polymer.

The crosslinked elastic layer has an intermediate layer made of the crosslinked rubber polymer (II) and an inner layer made of the crosslinked polymer (I) and covered in contact with the intermediate layer. As for the layer of the crosslinked elastic body, it is preferable that the inner layer and the intermediate layer form a core and a shell.

The crosslinked polymer (I) is composed of a structural unit derived from methyl methacrylate, a structural unit derived from a monofunctional monomer other than methyl methacrylate, and a structural unit derived from a polyfunctional monomer.

The amount of the structural unit derived from methyl methacrylate constituting the crosslinked polymer (I) is 40 to 98.5% by mass, preferably 45 to 95% by mass, based on the mass of the crosslinked polymer (I). ..

The amount of the structural unit derived from the monofunctional monomer other than methyl methacrylate constituting the crosslinked polymer (I) is 1 to 59.5% by mass, preferably 1 to 59.5% by mass, based on the mass of the crosslinked polymer (I). It is 5 to 55% by mass.
Examples of the monofunctional monomer other than methyl methacrylate include methacrylic ester other than methyl methacrylate such as ethyl methacrylate, butyl methacrylate and cyclohexyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, and 2 acrylate. Acrylic esters such as-ethylhexyl and propyl acrylate; aromatic vinyl compounds such as styrene, p-methylstyrene and α-methylstyrene; maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide and NO-chlorophenylmaleimide Can be mentioned.

The amount of the structural unit derived from the polyfunctional monomer constituting the crosslinked polymer (I) is 0.05 to 0.4% by mass, preferably 0.1, based on the mass of the crosslinked polymer (I). ~ 0.3% by mass.
Examples of the polyfunctional monomer include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, and triallyl. Isocyanurate and the like can be mentioned.

The inner layer may be a single layer made of one kind of crosslinked polymer (I) or a multi-layer made of two or more kinds of crosslinked polymers (I).

The amount of the crosslinked polymer (I) is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and further preferably 10 to 30% by mass with respect to the mass of the acrylic multilayer polymer.

The inner layer made of the crosslinked polymer (I) has functions such as controlling the flexibility of the layer of the crosslinked elastic body and storing low molecular weight additives such as an ultraviolet absorber. It is preferably a multi-layer composed of a crosslinked polymer (I) of more than one species.

The crosslinked rubber polymer (II) is a structural unit derived from an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and / or a structural unit derived from a conjugated diene, and a structural unit derived from a polyfunctional monomer. Consists of.

The amount of the structural unit derived from the acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and / or the structural unit derived from the conjugated diene constituting the crosslinked rubber polymer (II) is determined by the crosslinked rubber polymer (II). It is 98.3 to 99% by mass, preferably 95 to 98% by mass, based on the mass of the above.

Examples of the acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and propyl acrylate.

Examples of the conjugated diene include 1,3-butadiene, isoprene and the like.

The amount of the structural unit derived from the polyfunctional monomer constituting the crosslinked rubber polymer (II) is 1 to 1.7% by mass, preferably 1.2, based on the mass of the crosslinked rubber polymer (II). It is ~ 1.6% by mass, more preferably 1.3 to 1.5% by mass.
Examples of the polyfunctional monomer include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, and triallyl. Isocyanurate and the like can be mentioned.

From the viewpoint of improving bending resistance, the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) is relative to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II). The mass ratio of is preferably 0.05 to 0.25, more preferably 0.1 to 0.2. The glass transition temperature of the crosslinked rubber polymer (II) is preferably lower than the glass transition temperature of the crosslinked polymer (I).

The intermediate layer may be a single layer made of one kind of crosslinked rubber polymer (II) or a multi-layer made of two or more kinds of crosslinked rubber polymer (II).

The amount of the crosslinked rubber polymer (II) is preferably 20 to 55% by mass, more preferably 25 to 45% by mass, and further preferably 30 to 40% by mass with respect to the mass of the acrylic multilayer polymer.

The intermediate layer made of the crosslinked rubber polymer (II) mainly has a role of imparting flexibility to the methacrylic resin composition of the present invention.

It is preferable that the molecular chains of the crosslinked polymer (I) constituting the inner layer and the crosslinked rubber polymer (II) constituting the intermediate layer are connected by a graft bond. Further, it is preferable that the molecular chains of the crosslinked rubber polymer (II) constituting the intermediate layer and the thermoplastic polymer (III) constituting the outer layer are connected by a graft bond. The graft bond is generated by a polymerization method (graft polymerization method) in which a substituent bonded to the main chain of the already completed polymer is used as a reaction active site and a branch portion is newly extended from the active site. It is a bond that connects the main chain and the branch part.

In the acrylic multilayer polymer used in the present invention, the average diameter (d) of the crosslinked elastic layer is preferably 60 to 110 nm, more preferably 65 to 105 nm, and further preferably 70 to 100 nm. The average diameter d (nm) of the layer of the crosslinked elastic body in the present invention can be measured as follows. Using a hydraulic press molding machine, the methacryl resin composition has a mold size of 50 mm × 120 mm, a press temperature of 250 ° C., a preheating time of 3 minutes, a press pressure of 50 kg / cm ² , a press time of 30 seconds, a cooling temperature of 20 ° C., and cooling. It is molded into a 3 mm flat plate under the conditions of a pressure of 50 kg / cm ^{2 and a cooling time of 10 minutes.} Using a microtome, the obtained flat plate is cut at −100 ° C. in a direction parallel to the long side to obtain a slice having a thickness of 40 nm, and the slice is dyed with ruthenium. The dyed flakes are observed with a scanning transmission electron microscope (JSM7600F manufactured by JEOL Ltd.) at an acceleration voltage of 25 kV and a photograph is taken. Measure the minor axis and major axis of the ruthenium-stained part (exposed section of the crosslinked elastic body layer), and set (minor axis + major axis) / 2 as the diameter of the crosslinked elastic body layer, and after measuring 20 or more, Calculate the average value (average diameter) of the numbers.

The acrylic multilayer polymer used in the present invention has a graft ratio of preferably 33 to 50% by mass, more preferably 35 to 48% by mass, and even more preferably 40 to 45% by mass. The smaller the graft ratio, the more flexible the layer of the crosslinked elastic body tends to be, and the more the tensile elongation and the bending resistance tend to be improved. As the graft ratio increases, the elasticity of the layer of the crosslinked elastic body tends to improve, and the transparency tends to improve.

The graft ratio can be adjusted by controlling the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II). For example, a polyfunctional monomer having a double bond equivalent of preferably 50 to 250, more preferably 60 to 200 is adopted for the crosslinked rubber polymer (II) to form the crosslinked rubber polymer (II). The amount of the structural unit derived from the functional monomer is preferably 0.6 to 3.0% by mass, more preferably 0.8 to 2.0% by mass, based on the mass of the crosslinked rubber polymer (II). , More preferably 1.0 to 1.7% by mass. The double bond equivalent is a value obtained by dividing the molecular weight of the polyfunctional monomer by the number of double bonds present in one molecule of the polyfunctional monomer.

_{The graft ratio is the ratio R of the mass w 1} of the acetone insoluble matter in the acrylic multilayer polymer and the total mass of the crosslinked polymer (I) and the crosslinked rubber polymer (II) to the _{mass w 0} of the acrylic multilayer polymer. From, it is calculated by the following formula.
Graft rate = 100 × [w ₁ −w ₀ × R] / [w ₀ × R]

The acrylic multilayer polymer is not particularly limited depending on the production method thereof. For example, emulsion polymerization and the like can be mentioned.
In the case of emulsion polymerization, for example, the monomer (i) for forming the crosslinked polymer (I) is emulsion-polymerized to obtain a latex containing the crosslinked polymer (I), and the crosslinked rubber polymer (i) is obtained. A monomer (ii) for constituting II) is added, and the monomer (ii) is seed-emulsified polymerized to obtain a latex containing a crosslinked polymer (I) and a crosslinked rubber polymer (II). , The monomer (iii) for forming the thermoplastic polymer (III) can be added thereto, and the monomer (iii) can be seed-emulsified polymerized to obtain a latex containing an acrylic multilayer polymer. it can. Emulsion polymerization is a known method used to obtain a latex containing a polymer. Seed emulsion polymerization is a method in which a monomer polymerization reaction is carried out on the surface of seed particles. Seed emulsion polymerization is preferably used to obtain core-shell structural polymer particles.

The polymerization initiator used in the emulsion polymerization and the seed emulsion polymerization is not particularly limited. Examples of the polymerization initiator include water-soluble inorganic initiators such as potassium persulfate and ammonium persulfate; redox initiators obtained by using a sulfite or thiosulfate in combination with the inorganic initiators; and organic peroxides. Examples thereof include a redox initiator formed by using ferrous salt or sodium sulfoxylate in combination. The polymerization initiator may be added to the reaction system all at once at the start of polymerization, or may be added to the reaction system separately at the start of polymerization and during the polymerization in consideration of the reaction rate and the like.

The emulsifier used in the emulsion polymerization and the seed emulsion polymerization is not particularly limited. Examples of the emulsifier include dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium dilauryl sulfosuccinate, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, and alkyl sulfates such as sodium dodecyl sulfate; nonions. Polyoxyethylene alkyl ethers and the like; nonionic and anionic emulsifiers, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene alkyl ether sulfate, alkyl ether carboxylics such as sodium polyoxyethylene tridecyl ether acetate, etc. Sulfates and the like can be mentioned. The number of moles of oxyethylene structural units added in the nonionic emulsifier and the nonionic / anionic emulsifier is preferably 30 mol or less, more preferably 20 mol or less, and most preferably 20 mol or less in order to prevent the foaming property of the emulsifier from becoming extremely large. Is less than 10 moles. These emulsifiers can be used alone or in combination of two or more.

The amount of the polymerization initiator and emulsifier used can be appropriately set so that the average particle size (D) of the acrylic multilayer polymer contained in the latex is within a desired range. The amount of the emulsifier used varies depending on the type of emulsifier, but is preferably 0.5 to 3 parts by mass, more preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the total amount of the monomers for producing the acrylic multilayer polymer. Is 1 to 2 parts by mass.

The average particle size (D) of the acrylic multilayer polymer contained in the latex is preferably 80 nm or more and 150 nm or less, and more preferably 90 nm or more and 120 nm or less. If the average particle size D of the acrylic multilayer polymer is too small, the viscosity of the latex tends to increase. If the average particle size D of the acrylic multilayer polymer is too large, the stress whitening resistance tends to decrease.
The average particle size D of the acrylic multilayer polymer contained in the latex can be determined as follows. The latex containing the acrylic multilayer polymer is diluted with ion-exchanged water so as to have a concentration of 0.05% by mass, and the obtained diluted solution is thinly cast on a support plate and dried. A gold-palladium alloy is vapor-deposited on the dried product, which is observed with a scanning transmission electron microscope (JSM7600F, manufactured by JEOL Ltd.) to determine the number average particle size.

In the present invention, the emulsion polymerization of the monomer (i), the seed emulsion polymerization of the monomer (ii) and the seed emulsion polymerization of the monomer (iii) may be sequentially carried out in one polymerization tank. The polymerization tank may be changed each time the emulsion polymerization of the monomer (i), the seed emulsion polymerization of the monomer (ii), and the seed emulsion polymerization of the monomer (iii) are carried out in sequence. In the present invention, it is preferable to carry out each polymerization sequentially in one polymerization tank. The temperature of the reaction system during the polymerization is preferably 30 to 120 ° C, more preferably 50 to 100 ° C.

Further, in any of the emulsion polymerization of the monomer (i), the seed emulsion polymerization of the monomer (ii) and the seed emulsion polymerization of the monomer (iii), if necessary, a reactive ultraviolet absorber, for example, , 2- [2-Hydroxy-5- (2-methacryloyloxyethyl) phenyl] -2H-1,2,3-benzotriazole and the like can be added. A reactive UV absorber is introduced into the molecular chain of the acrylic multilayer polymer, and the UV resistance of the acrylic multilayer polymer is improved. The amount of the reactive ultraviolet absorber added is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the total amount of the monomers used in the production of the acrylic multilayer polymer.

Chain transfer agents can be used in each polymerization for the regulation of molecular weight. The chain transfer agent used for each polymerization is not particularly limited. Examples of the chain transfer agent include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-hexadecyl mercaptan; xanthogen disulfides such as dimethyl xanthogen disulfide and diethyl xanthogen disulfide; tetrathiuram disulfide. Thiol disulfides such as; carbon tetrachloride, halogenated hydrocarbons such as ethylene bromide, etc. can be mentioned. The amount of the chain transfer agent used can be appropriately set within a range in which each of the polymers (I), (II), and (III) can be adjusted to a predetermined molecular weight. The amount of the chain transfer agent used in the seed emulsion polymerization of the monomer (iii) can be appropriately set so that the acrylic multilayer polymer has a desired melt flow rate. The suitable amount of the chain transfer agent used in each polymerization depends on the amount of the polymerization initiator used in the polymerization and the like. The amount of the chain transfer agent used in the seed emulsion polymerization of the monomer (iii) is preferably 0.05 to 2 parts by mass, more preferably 0.08 with respect to 100 parts by mass of the monomer (iii). ~ 1 part by mass.

Next, the latex obtained by the above polymerization is solidified. The coagulation of the latex can be performed by a known method. Examples of the coagulation method include a freeze coagulation method, a salting out coagulation method, and an acid coagulation method. Of these, the freeze-coagulation method that does not require the addition of a coagulant as an impurity or the salting-out coagulation method that can be washed is preferable from the viewpoint that a coagulated product with few impurities can be obtained. Latex spray drying can also be used instead of latex coagulation. Before solidifying or spray-drying the latex, it is preferable to filter the latex with a wire mesh having a mesh size of 50 μm or less in order to remove foreign substances.

The slurry obtained by coagulation is washed if necessary and then dehydrated. It is preferable to repeat washing and dehydration so that the characteristics of the acrylic multilayer polymer are within the desired range. Water-soluble components such as emulsifiers and catalysts can be removed from the slurry by washing and dehydrating the slurry. The slurry can be washed and dehydrated by, for example, a filter press, a belt press, a Gina type centrifuge, a screw decanter type centrifuge, or the like. From the viewpoint of productivity and cleaning efficiency, it is preferable to use a decanter type centrifugal dehydrator. The slurry is preferably washed and dehydrated at least twice. The greater the number of washes and dehydrations, the lower the residual amount of water-soluble components. However, from the viewpoint of productivity, the number of washings and dehydrations is preferably 3 times or less.

Dehydration is carried out so that the water content of the slurry is preferably less than 0.3% by mass, more preferably less than 0.2% by mass. Drying of the dehydrated slurry is preferably carried out at a temperature of 40 to 80 ° C. in order to further reduce the water content while preventing deterioration of the polymer. The dehydrated slurry is dried over an average residence time of preferably 0.5 to 5 hours, more preferably 1 to 3 hours. The lower the water content after dehydration and drying, the better the warm water bleaching resistance and boiling water bleaching resistance tend to be.

The thermoplastic resin used in the present invention comprises a structural unit derived from methyl methacrylate and, if necessary, a structural unit derived from a monofunctional monomer other than methyl methacrylate.

The amount of the structural unit derived from methyl methacrylate in the thermoplastic resin is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, based on the mass of all the structural units of the thermoplastic resin. The amount of structural units derived from a monofunctional monomer other than methyl methacrylate in the thermoplastic resin is preferably 0 to 40% by mass, more preferably 0 to 20% by mass, based on the mass of all structural units of the thermoplastic resin. It is mass%.

Examples of monofunctional monomers other than methyl methacrylate include methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and benzyl acrylate. Acrylic acid ester monomers such as: ethyl methacrylate, butyl methacrylate, propyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate and other methacrylic acid esters other than methyl methacrylate; vinyl acetate, etc. Aromatic vinyl compounds such as styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, vinylnaphthalene; ethylenically unsaturated nitriles such as acrylonitrile and methacrylic acid; acrylic acid, methacrylic acid, Α, β-unsaturated carboxylic acids such as crotonic acid; maleimide compounds such as N-ethylmaleimide and N-cyclohexylmaleimide can be mentioned. Of these, acrylic acid alkyl esters having an alkyl group having 1 to 6 carbon atoms are preferable. The monofunctional monomer can be used alone or in combination of two or more. It is preferable that the thermoplastic resin does not contain a structural unit derived from a polyfunctional monomer.

The thermoplastic resin has a glass transition temperature of preferably 95 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 105 ° C. or higher. The thermoplastic resin has a melt flow rate of preferably 0.5 to 20 g / 10 minutes, more preferably 0.8 to 10 g / 10 minutes under a load of 230 ° C. and 3.8 kg.

The thermoplastic resin has a weight average molecular weight (Mw) of preferably 60,000 to 150,000, more preferably 70,000 to 140,000. The weight average molecular weight (Mw) of the thermoplastic resin is set so that the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the acetone-soluble components contained in the methacrylic resin composition is in a desired range. Is preferable.

The thermoplastic resin is not particularly limited by the production method thereof. For example, it can be obtained by carrying out a known polymerization reaction such as a radical polymerization reaction or an anionic polymerization reaction by a known polymerization method such as a massive polymerization method or a solution polymerization method. A commercially available thermoplastic resin can be used. For example, manufactured by Kuraray Co., Ltd. parapet ^TM, Mitsubishi Rayon Co., Ltd. Acrypet ^TM, manufactured by Sumitomo Chemical Co., Ltd. SUMIPEX ^TM, Asahi Kasei Chemicals Co., Ltd. del Pets ^TM, DOW CHEMICAL Co., Ltd. Paragurasu ^TM and Orogurasu ^TM, etc. Methacrylic resin can be mentioned. Further, the methacrylic resin specified in ISO 8257-1 may be used.
The amount of the thermoplastic resin contained in the methacrylic resin composition of the present invention is preferably 1 to 45 parts by mass, more preferably 5 to 40 parts by mass, and further preferably 10 parts by mass with respect to 100 parts by mass of the acrylic multilayer polymer. ~ 35 parts by mass.

The methacrylic resin composition of the present invention is used for known resins such as ultraviolet absorbers, antioxidants, light stabilizers, antioxidants, plasticizers, polymer processing aids, lubricants, dyes and pigments, if necessary. Additives may be included. The total content of the resin additive is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the methacrylic resin composition. The resin additive may be added at the time of melting the resin, may be dry-blended into the resin pellets, or may be added by the masterbatch method.

The polymer processing aid is a polymer compound having a structural unit of 60% by mass or more derived from methyl methacrylate and a structural unit of 40% by mass or less derived from a vinyl-based monomer other than methyl methacrylate. Examples of the vinyl-based monomer include methacrylic acid esters such as ethyl methacrylate, butyl methacrylate and cyclohexyl methacrylate; aromatic vinyl compounds such as styrene, p-methylstyrene and α-methylstyrene; N-propylmaleimide. , N-cyclohexylmaleimide, No-chlorophenylmaleimide and other maleimide compounds can be mentioned. The ultimate viscosity of the polymer processing aid is preferably 3 to 6 dl / g. When the viscosity is in this range, the effect of improving the film-forming property tends to be high.
As the polymer processing aid, a commercially available one can also be used. Commercially available polymer processing aids, Mitsubishi Rayon Co., Ltd. Metablen ^TM, and the like Kaneka Co. Kane Ace ^TM, DOW CHEMICAL Co. Paraloid ^TM.

Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines and the like. These may be used individually by 1 type or in combination of 2 or more type. Among these, benzotriazoles (compounds having a benzotriazole skeleton) and triazines (compounds having a triazine skeleton) are preferable. Benzotriazoles or triazines are highly effective in suppressing deterioration of the resin due to ultraviolet rays (for example, yellowing).

Examples of benzotriazoles include 2- (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (manufactured by BASF; trade name TINUVIN329), 2- (2H-). Benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name tertUVIN234), 2,2'-methylenebis [6- (2H-benzotriazole-2) -Il) -4-tert-octylphenol] (manufactured by ADEKA; LA-31), 2- (5-octylthio-2H-benzotriazole-2-yl) -6-tert-butyl-4-methylphenol, etc. be able to.

Examples of triazines include 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine (manufactured by ADEKA; LA-F70) and its analogs. A certain hydroxyphenyltriazine-based ultraviolet absorber (manufactured by BASF; CGL777, TINUVIN460, TINUVIN479, etc.), 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, etc. Can be mentioned.

In addition, an ultraviolet absorber having a maximum molar extinction coefficient εmax at a wavelength of 380 to 450 nm of 1200 dm ³ mol ^-1 cm ^-1 or less can be preferably used. Examples of such an ultraviolet absorber include 2-ethyl-2'-ethoxy-oxalanilide (manufactured by Clariant Japan Co., Ltd .; trade name: Sandeuboa VSU).

The methacrylic resin composition of the present invention has the total mass of the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) and the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II). Is x% by mass with respect to the total mass of the crosslinked polymer (I) and the crosslinked rubber polymer (II), and the mass of the acetone-soluble component contained in the methacrylic resin composition is based on the mass of the methacrylic resin composition. When the weight is y mass% and the average diameter of the layer of the crosslinked elastic body is d nanometers, the value calculated by the formula: x · d / y is 1.0 or more and 3.0 or less, preferably 1. It is 2 or more and 2.8 or less, more preferably 1.4 or more and 2.5 or less. Formula: If the value calculated by x · d / y is less than 1.0, the stress whitening resistance tends to decrease. On the other hand, if the formula (value calculated by x · d / y) exceeds 3.5, the ductility tends to decrease.

The amount of the crosslinked elastic body in the methacrylic resin composition of the present invention is preferably the amount of the crosslinked elastic body with respect to the amount of the methacrylic resin composition from the viewpoint of achieving both improvement of ductility, folding resistance and tear strength and improvement of film forming property. It is 20 to 40% by mass, more preferably 25 to 35% by mass, and even more preferably 26 to 30% by mass.

The amount of the acetone-soluble component contained in the methacrylic resin composition is preferably higher than that of the methacrylic resin composition from the viewpoint of achieving both improvement of ductility, folding resistance and tear strength and improvement of film forming property. It is 48 to 60% by mass, preferably 49 to 59% by mass, and more preferably 49 to 58% by mass.

The amount of acetone-soluble matter is determined as follows. 2 g (w0) of the precisely weighed methacrylic resin composition is added to 100 ml of acetone, and the mixture is stirred at room temperature for 24 hours. The obtained liquid is placed in a centrifuge tube and centrifuged at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then decanted to leave the insoluble matter at the bottom of the sedimentation tube. Acetone is added to the sedimentation tube and stirred. Centrifuge at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then removed by decantation. Acetone is added to the sedimentation tube again and the mixture is stirred. Centrifuge at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then removed by decantation. The insoluble matter is taken out from the bottom of the sedimentation tube, dried at 80 ° C., and its mass w1 is measured. The amount of the acetone-soluble component is calculated by the formula: 100 × (w0-w1) / w0.

The acetone-soluble component can be obtained by removing acetone from the supernatant at 50 ° C. under reduced pressure and drying the solid residue at 80 ° C.
The ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of the acetone-soluble component is preferably 2.3 to 3.0 from the viewpoint of achieving both the improvement of film forming property and the improvement of hot water whitening resistance. , More preferably 2.4 to 2.8, and even more preferably 2.43 to 2.7. The larger the Mw / Mn of the acetone-soluble component, the better the film-forming property tends to be. The smaller the Mw / Mn of the acetone-soluble component, the more the warm water whitening resistance tends to improve.

Since the methacrylic resin composition of the present invention has excellent adhesion to the thermoplastic polymer resin, a laminate having a layer made of the methacrylic resin composition of the present invention and a layer made of the thermoplastic polymer resin is preferable. Is suitable for the production of laminated films. The laminate is not particularly limited by the method for producing the laminate. For example, a method for producing a laminate including melting the methacrylic resin composition of the present invention and the thermoplastic polymer resin separately and coextruding them, a molded product made of the thermoplastic polymer resin, for example, a film or a sheet. A method for producing a laminate including press molding, coating extrusion molding, insert molding or in-mold molding of the methacrylic resin composition of the present invention on a plate or the like, a molded product made of the methacrylic resin composition of the present invention, for example. , A method for producing a laminate including press molding, coating extrusion molding, insert molding or in-mold molding of a thermoplastic polymer resin on a film, sheet, plate, etc., a molded product made of the methacrylic resin composition of the present invention. Examples thereof include a method for producing a laminate including welding, bonding, pressure bonding, and the like of a molded product made of a thermoplastic polymer resin and a molded product.
Examples of the thermoplastic polymer resin that can be used for the laminate include polycarbonate-based polymers, vinyl chloride-based polymers, vinylidene fluoride-based polymers, methacrylic resins, ABS resins, AES resins, AS resins, and the above-mentioned thermoplastics. Resin and the like can be mentioned.

The methacrylic resin composition of the present invention can be applied to various uses. For example, signboard parts such as advertising towers, stand signs, sleeve signs, column signs, roof signs; display parts such as showcases, dividers, and store displays; fluorescent light covers, mood lighting covers, lamp shades, light ceilings, and light walls. , Lighting parts such as chandeliers; Interior parts such as pendants and mirrors; Doors, dome, safety windowpanes, partitions, staircase wainscots, balcony wainscots, roofs of leisure buildings, sashes, kitchen doors, doors and other building parts; Transport equipment related parts such as aircraft windshields, pilot visors, motorcycles, motor boat windshields, bus shading plates, automobile side visors, rear visors, head wings, headlight covers; audiovisual nameplates, stereo covers, TV protective masks, automatic Electronic equipment parts such as display covers for vending machines; Medical equipment parts such as incubators and roentgen parts; Equipment-related parts such as machine covers, instrument covers, experimental equipment, rulers, dials, observation windows; for front lights of display equipment Optical components such as light guide plates and films, light guide plates and films for backlights, liquid crystal protective plates, frennel lenses, lenticular lenses, front plates of various displays, diffusers, reflectors; road signs, guide plates, curved mirrors, soundproofing Transportation-related parts such as walls; Surface materials for automobile interiors, surface materials for mobile phones, film materials such as marking films; Parts for home appliances such as canopy materials and control panels for washing machines, and top panels for rice cookers; Examples include greenhouses, large water tanks, box water tanks, clock panels, bathtubs, sanitaries, desk mats, game parts, toys, and face protection masks during welding.

The methacrylic resin composition of the present invention is excellent in transparency and processability, and bleed-out of an ultraviolet absorber is suppressed. Therefore, for example, a surface layer of a building material for indoor and outdoor use such as a sash, a door, and a kitchen door, and various covers. Optical devices such as various terminal boards, printed wiring boards, speakers, microscopes, binoculars, cameras, clocks, and finder for cameras, VTRs, projection TVs, etc. as parts related to video / optical recording / optical communication / information equipment. Filters, prisms, Frenel lenses, protective films for various optical disk (VD, CD, DVD, MD, LD, etc.) substrates, optical switches, optical connectors, liquid crystal displays, light guide film sheets for liquid crystal displays, flat panel displays, flat panels Light guide film sheet for display, plasma display, light guide film sheet for plasma display, light guide film sheet for electronic paper, retardation film sheet, polarizing film sheet, polarizing plate protective film sheet, polarizer protection Film sheet, wavelength plate, light diffusing film sheet, prism film sheet, reflective film sheet, antireflection film sheet, viewing angle expansion film sheet, antiglare film sheet, brightness improvement film sheet, liquid crystal display, etc. It can be suitably applied to applications such as display element substrates for electroluminescence applications, touch panels, light guide film sheets for touch panels, spacers between various front plates and various modules, and the like.
Specifically, for example, various liquid crystal display elements such as mobile phones, digital information terminals, pagers, navigation systems, in-vehicle liquid crystal displays, liquid crystal monitors, dimming panels, OA device displays, AV device displays, and electroluminescence displays. It can be used for elements, touch panels, and the like. In addition, from the viewpoint of excellent weather resistance, for example, building interior / exterior members, curtain walls, roofing members, roofing materials, window members, gutters, exteriors, wall materials, flooring materials, building materials, etc. It is particularly suitably applicable to known building material applications such as road construction members, retroreflective film sheets, agricultural film sheets, lighting covers, signboards, and translucent sound insulation walls.

The methacrylic resin composition of the present invention can also be applied to a solar cell surface protective film, a solar cell sealing film, a solar cell back surface protective film, a solar cell substrate film, a gas barrier film protective film, and the like for solar cell applications. is there.

The film of the present invention comprises the methacrylic resin composition of the present invention. The film of the present invention can be obtained by a known film forming method. Examples of the film forming method include an extrusion molding method, an inflation molding method, a blow molding method, a melt casting method, and a solution casting method. Of these, the extrusion molding method is preferable. According to the extrusion molding method, it is possible to obtain a film having improved toughness, excellent handleability, and an excellent balance between toughness, surface hardness and rigidity. The temperature of the resin discharged from the extruder is preferably set to 160 to 270 ° C, more preferably 220 to 260 ° C.

From the viewpoint of obtaining a film having good surface smoothness, good mirror gloss, and low haze among the extrusion molding methods, the methacrylic resin composition of the present invention is extruded from a T-die in a molten state, and then two or more of them are extruded. A method including forming a film by sandwiching the film with a mirror surface roll or a mirror surface belt is preferable. The mirror surface roll or mirror surface belt is preferably made of metal. The linear pressure between the pair of mirror surface rolls or mirror surface belts is preferably 2 N / mm or more, more preferably 10 N / mm or more, and even more preferably 30 N / mm or more.

Further, it is preferable that the surface temperature of the mirror surface roll or the mirror surface belt is 130 ° C. or lower. Further, it is preferable that at least one of the mirror surface rolls or the mirror surface belts has a surface temperature of 60 ° C. or higher. When the surface temperature is set to such a value, the resin discharged from the extruder can be cooled at a speed faster than natural cooling, and it is easy to produce a film having excellent surface smoothness and low haze.

The film of the present invention may be stretched. By the stretching treatment, the mechanical strength is increased, and a film that is hard to crack can be obtained. The stretching method is not particularly limited, and examples thereof include a uniaxial stretching method, a simultaneous biaxial stretching method, a sequential biaxial stretching method, and a tuber stretching method. The temperature at the time of stretching is preferably 100 to 200 ° C., more preferably 120 ° C. to 160 ° C. from the viewpoint that the film can be uniformly stretched and a high-strength film can be obtained. Stretching is usually performed at 100-5000% / min on a length basis. Stretching is preferably performed so that the area ratio is 1.5 to 8 times. By performing heat fixation after stretching, a film having less heat shrinkage can be obtained.

The thickness of the film of the present invention is not particularly limited, but is preferably 0.2 mm or less, more preferably 1 to 200 μm, still more preferably 10 to 100 μm, and even more preferably 15 to 75 μm. Generally, the thinner the film, the lower the UV absorption capacity. Since the methacrylic resin composition of the present invention is unlikely to cause bleed-out even when a large amount of an ultraviolet absorber is added, it is easy to increase the ultraviolet absorbing ability even in a thin film. The methacrylic resin composition of the present invention is superior in film-forming property as compared with a film formed by methacrylic resin alone, and has small thickness unevenness in a thin thickness. In addition, it has excellent stress whitening resistance and does not whiten even when bent.

The film of the present invention has high transparency, high heat resistance, suppresses the occurrence of mold stains, bleed-out, etc. even during molding at high temperatures, and can reduce the occurrence of problems due to evaporation of the ultraviolet absorber. Moreover, since it can be formed thin, a polarizing element protective film, a retardation film, a liquid crystal protective plate, a surface material of a portable information terminal, a display window protective film of a portable information terminal, a light guide film, silver nanowires and carbon nanotubes are placed on the surface. It is suitable for coated transparent conductive films, front plate applications of various displays, and the like. In particular, the film of the present invention has a small phase difference and is therefore suitable as a polarizer protective film.
The film of the present invention has high transparency and processability, and bleed-out is unlikely to occur even if a large amount of an ultraviolet absorber is added. Therefore, a film for building materials, a retroreflective film, an IR cut film, a security film, and a shatterproof film , Decorative film, metal decorative film, back sheet of solar cell, front sheet for flexible solar cell, shrink film, film for in-mold label, base film for gas barrier film.

A functional layer can be provided on at least one side of the film or sheet of the present invention. Examples of the functional layer include a hard coat layer, an anti-glare layer, an antireflection layer, an anti-sticking layer, a light diffusion layer, an antiglare layer, an antistatic layer, an antifouling layer, an slippery layer, and a gas barrier layer.

Next, the effects of the present invention will be described with reference to Examples and Comparative Examples. “Parts” and “%” used in Examples and Comparative Examples all mean “parts by mass” and “% by mass”.

The abbreviations of the monomers and the like used in Examples and Comparative Examples are as follows.
MMA: Methyl methacrylate ALMA: Allyl methacrylate MA: Methyl acrylate BA: Butyl acrylate n-OM: n-octyl mercaptan UVA: 2,2'-methylenebis [6- (2H-benzotriazole-2-yl)- 4-t-octylphenol] (manufactured by ADEKA; LA-31)
B1: Thermoplastic resin (Kuraray ^{Parapet TM} EH1000, Methacrylic Resin Co., Ltd.)
B2: Thermoplastic resin (Kuraray ^{Parapet TM} HR1000L, Methacrylic Resin Co., Ltd.)
B3: Thermoplastic resin (Kuraray Parapet ^TM HR-G1000, Methacrylic Resin Co., Ltd.)

The physical characteristics of the acrylic multilayer polymers obtained in Examples and Comparative Examples were measured as follows.

[Average diameter of crosslinked elastic layer: d]
Using a hydraulic press molding machine, the methacrylic resin composition has a mold size of 50 mm × 120 mm, a press temperature of 250 ° C., a preheating time of 3 minutes, a press pressure of 50 kg / cm ² , a press time of 30 seconds, a cooling temperature of 20 ° C., and cooling. The acrylic multilayer polymer was molded into a 3 mm flat plate under the conditions of a pressure of 50 kg / cm ^{2 and a cooling time of 10 minutes.} Using a microtome, the obtained flat plate was cut at −100 ° C. in a direction parallel to the long side to obtain a thin section having a thickness of 40 nm. The flakes were dyed with ruthenium. The dyed flakes were observed with a scanning transmission electron microscope (JSM7600F manufactured by JEOL Ltd.) at an acceleration voltage of 25 KV and photographed (see FIG. 1. The white line at the bottom of the photograph represents 100 nm). Measure the minor axis and major axis of the ruthenium-stained part (exposed section of the crosslinked elastic body layer), and set (minor axis + major axis) / 2 as the diameter of the crosslinked elastic body layer, and after measuring 20 or more, The number average value (average diameter d) was calculated.

[Acetone-soluble content]
2 g (w0) of the precisely weighed methacrylic resin composition was added to 100 ml of acetone, and the mixture was stirred at room temperature for 24 hours. The obtained liquid was placed in a centrifuge tube having a known mass and centrifuged at 5 ° C. and 20000 rpm for 120 minutes. The supernatant (1) was then separated by decantation, leaving the sediment at the bottom of the centrifuge tube. Acetone was added to the centrifuge tube and the mixture was stirred. This was centrifuged at 5 ° C. and 2000 rpm for 120 minutes. The supernatant (2) was then separated by decantation, leaving the sediment at the bottom of the centrifuge tube. The centrifuge tube with the precipitate on the bottom was placed in a vacuum dryer at 50 ° C.-400 torr and dried at 80 ° C.-760 torr for 8 hours. The masses of the dried sediment (acetone insoluble matter) and the centrifuge tube were measured, and the mass of the centrifuge tube was subtracted from the values to calculate the mass of the acetone insoluble matter (w1). The acetone-soluble content (mass%) was calculated by the formula: 100 × (w0-w1) / w0.
Acetone-soluble components are obtained by removing acetone from the supernatant liquids (supernatant liquid (1) and supernatant liquid (2)) separated above at 50 ° C. under reduced pressure using a rotary evaporator and drying the solid residue at 80 ° C. Got

[Graft rate]
Approximately 2 g of the acrylic multilayer polymer was precisely weighed (w ₀ ) and immersed in 100 g of acetone at 23 ° C. for 24 hours to dissolve it. Then, it is separated into an acetone-insoluble component and an acetone-soluble component by centrifugation, and each is dried to determine _{the mass (w 1) of the acetone-insoluble component.} Further, it is calculated by the following formula from the ratio R of the total mass of the crosslinked polymer (I) and the crosslinked rubber polymer (II) to the _{mass w 0} of the acrylic multilayer polymer.
Graft rate = 100 × [w ₁ −w ₀ × R] / [w ₀ × R]

[Molecular weight of acetone-soluble matter]
A solution was obtained by dissolving 6 mg of acetone-soluble matter in 10 ml of tetrahydrofuran. By measuring the chromatogram by gel permeation chromatography (GPC) under the following conditions and converting it to the molecular weight of standard polymethyl methacrylate, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw) are obtained. / Mn) was determined.
The baseline is that the slope of the peak on the high molecular weight side of the GPC chart changes from zero to positive when viewed from the earliest retention time, and the slope of the peak on the low molecular weight side is negative when viewed from the earliest retention time. The line connecting the points that change from to zero.
GPC device: manufactured by Tosoh Corporation, HLC-8320
Detector: Differential refractive index detector Column: Two TSKgel SuperMultipore HZM-M manufactured by Tosoh Corporation and SuperHZ4000 connected in series were used.
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 ml / min Column temperature: 40 ° C
Calibration curve: Prepared using data of 11 standard polymethyl methacrylates.

The effects brought about by the methacrylic resin compositions obtained in Examples and Comparative Examples were evaluated as follows.

[Film formation]
The methacrylic resin composition was dried at 80 ° C. for 12 hours. After that, the methacrylic resin composition was extruded at a extrusion rate of a methacrylic resin composition under the conditions of an extrusion temperature of 250 ° C., a die temperature of 250 ° C. The film was extruded at V0 and wound on a metal roll having a roll temperature of 80 ° C. at a winding speed of Vw to obtain a film having a thickness of 50 μm.
The thickness of 20 points of the obtained film was measured at intervals of 50 mm in the MD direction, and the standard deviation, the average value and the coefficient of variation [= (standard deviation / average value) × 100] were calculated from the measured values. The draft value (= Vw / V0) at which the coefficient of variation is 5% was determined. The larger the draft value, the better the film forming property.

[Haze]
A small piece of 50 mm × 50 mm was cut out from the film, and the haze (H0) of this small piece was measured using a haze meter MH-150 manufactured by Murakami Color Materials Research Institute.

[Ductility]
The film was punched out to obtain a JIS K 7127 (ISO572-3) type 1B test piece. The test piece was pulled at 200 mm / min and the elongation immediately before breaking was measured. This measurement was performed in the extrusion direction (MD) and in the direction perpendicular to it (TD). The tensile elongation was calculated by the formula: tensile elongation (%) = (elongation immediately before breaking / distance between chucks) × 100. The larger the tensile elongation, the higher the ductility.

[Stress whitening resistance]
Fragments of the test pieces broken in the tensile elongation measurement test were visually observed.
The case where the entire surface of the fragment was whitened was rated as "C", the case where only the broken portion was whitened was rated as "B", and the case where there was no whitened part was rated as "A".

<Production Example 1: Production of Acrylic Multilayer Polymer A1>
A reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, a monomer introduction tube and a reflux condenser was charged with 1050 parts of deionized water, 1 part of sodium dodecylbenzenesulfonate and 0.05 part of sodium carbonate for reaction. The inside of the reactor was sufficiently replaced with nitrogen gas to make it virtually oxygen-free. The temperature inside the reactor was set to 80 ° C. To that, 0.1 part of a 3% aqueous potassium persulfate solution was added, and the mixture was stirred for 5 minutes. Then, 26.2 parts of the mixture (i) consisting of MMA 49.9%, BA 49.9% and ALMA 0.2% was continuously added over 20 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.05 part of a 3% aqueous potassium persulfate solution was added to the reactor, and the mixture was stirred for 5 minutes. Then, 157.4 parts by mass of the mixture (ii) consisting of 5% MMA, 93.5% BA, and 1.5% ALMA was added continuously over 40 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.5 part of a 3% aqueous potassium persulfate solution was added to the reactor, and the mixture was stirred for 5 minutes. Then, 341.1 parts of the mixture (iii) consisting of 87.2% MMA, 12.5% BA, and 0.3% n-OM was continuously added over 100 minutes. After completion of the addition, a polymerization reaction was further carried out for at least 60 minutes so that the polymerization rate was 98% or more to obtain a latex containing an acrylic multilayer polymer A1 having a number average particle size of 100 nm.

Subsequently, the latex containing the acrylic multilayer polymer A1 was frozen at −30 ° C. for 4 hours. Frozen latex was put into twice the amount of warm water at 80 ° C. and dissolved to obtain a slurry. The slurry was kept at 80 ° C. for 20 minutes. Then, it was dehydrated and dried at 70 ° C. to obtain a powder of acrylic multilayer polymer A1.

<Manufacturing Example 2: Production of Acrylic Multilayer Polymer A2>
A reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, a monomer introduction tube and a reflux condenser was charged with 1050 parts of deionized water, 1 part of sodium dodecylbenzenesulfonate and 0.05 part of sodium carbonate for reaction. The inside of the reactor was sufficiently replaced with nitrogen gas to make it virtually oxygen-free. The temperature inside the reactor was set to 80 ° C. To that, 0.1 part of a 3% aqueous potassium persulfate solution was added, and the mixture was stirred for 5 minutes. Then 13.1 part of the mixture (i) consisting of 90.9% MMA, 9.0% BA and 0.1% ALMA was added continuously over 10 minutes. After completion of the addition, the polymerization reaction was further carried out for 20 minutes. Then 13.1 parts of the mixture (i2) consisting of 49.8% MMA, 49.9% BA and 0.3% ALMA was added continuously over 10 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.05 part of a 3% aqueous potassium persulfate solution was added to the reactor, and the mixture was stirred for 5 minutes. Then 157.4 parts of the mixture (ii) consisting of 5% MMA, 93.5% BA and 1.5% ALMA was added continuously over 40 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.5 part of a 3% aqueous potassium persulfate solution was put into the reactor and stirred for 5 minutes. Then, 341.1 parts of the mixture (iii) consisting of 95% MMA, 4.8% BA, and 0.2% n-OM was continuously added over 100 minutes. After completion of the addition, a polymerization reaction was further carried out for at least 60 minutes so that the polymerization rate was 98% or more to obtain a latex containing an acrylic multilayer polymer A2 having an average particle size of 100 nm. The graft ratio was 41% by mass. The average diameter of the layers of the crosslinked elastic body was 71 nm.
Subsequently, the latex containing the acrylic multilayer polymer A2 was frozen at −30 ° C. for 4 hours. Frozen latex was put into twice the amount of warm water at 80 ° C. and dissolved to obtain a slurry. The slurry was kept at 80 ° C. for 20 minutes. Then, it was dehydrated and dried at 70 ° C. to obtain a powder of acrylic multilayer polymer A2.

<Production Examples 3 to 8: Production of Acrylic Multilayer Polymers A3 to A8>
Acrylic multilayer polymers A3 to A8 powders were obtained in the same manner as in Production Example 1 except that the mixture (i), the mixture (ii) and the mixture (iii) were changed to the compositions and addition amounts shown in Table 1.

<Production Example 9: Production of Acrylic Multilayer Polymer A9>
Acrylic multilayer polymer A9 powder was obtained by the same method as in Production Example 1 except that the amount of sodium dodecylbenzenesulfonate was changed to 2 parts.

<Production Example 10: Production of Acrylic Multilayer Polymer A10>
A reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, a monomer introduction tube and a reflux condenser was charged with 1050 parts of deionized water, 1 part of sodium dodecylbenzenesulfonate and 0.05 part of sodium carbonate for reaction. The inside of the reactor was sufficiently replaced with nitrogen gas to make it virtually oxygen-free. The temperature inside the reactor was set to 80 ° C. 0.5 part of a 3% aqueous potassium persulfate solution was added thereto, and the mixture was stirred for 5 minutes. Then, 157.4 parts of the mixture (ii) consisting of 4.9% MMA, 93.8% BA and 1.3% ALMA was added continuously over 40 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.5 part of a 3% aqueous potassium persulfate solution was put into the reactor and stirred for 5 minutes. Then, 367.3 parts of the mixture (iii) consisting of 87.2% MMA, 12.5% BA and 0.3% n-OMA was continuously added over 100 minutes. After completion of the addition, the polymerization reaction was further carried out for at least 60 minutes so that the polymerization rate was 98% or more to obtain a latex containing the acrylic multilayer polymer A10 having a number average particle size of 100 nm.
Subsequently, the latex containing the acrylic multilayer polymer A10 was frozen at −30 ° C. for 4 hours. Frozen latex was put into twice the amount of warm water at 80 ° C. and dissolved to obtain a slurry. The slurry was kept at 80 ° C. for 20 minutes. Then, it was dehydrated and dried at 70 ° C. to obtain a powder of acrylic multilayer polymer A10.

(Example 1)
80.0 parts of acrylic multilayer polymer A1, 20.0 parts of thermoplastic resin B1 and 3.0 parts of UVA are mixed, and a twin-screw extruder (manufactured by Technobel Co., Ltd., trade name: KZW20TW-45MG) -NH-600) was kneaded and extruded at 250 ° C. to obtain a methacrylic resin composition P1. The methacrylic resin composition P1 was supplied to a uniaxial extruder with a vent, melt-kneaded at an average residence time of 3.5 minutes at 265 ° C., and extruded into a film from a T-die. The extruded film-like molten resin was wound on a mirror roll to obtain a film having a thickness of 50 μm. The evaluation results are shown in Table 2.

(Examples 2-9, Comparative Examples 1-5)
The methacrylic resin compositions P2 to P14 were obtained in the same manner as in Example 1 except that the blending ratios shown in Table 2 were changed. A film was obtained in the same manner as in Example 1 except that the methacrylic resin composition P1 was changed to the methacrylic resin compositions P2 to P14. The evaluation results are shown in Table 2.

Claims (7)

1 to 45 parts by mass of a thermoplastic resin consisting of 60% by mass or more of a structural unit derived from methyl methacrylate and 40% by mass or less of a structural unit derived from a monofunctional monomer other than methyl methacrylate, and a thermoplastic polymer (III). ), And 100 parts by mass of an acrylic multilayer polymer composed of a layer of a crosslinked elastic material covered in contact with the outer layer.
The crosslinked elastic layer has an intermediate layer made of the crosslinked rubber polymer (II) and an inner layer made of the crosslinked polymer (I) and covered in contact with the intermediate layer.
The crosslinked polymer (I) has a structural unit of 40 to 98.5% by mass derived from methyl methacrylate, a structural unit of 1 to 59.5% by mass derived from an acrylic acid ester, and a structure derived from a polyfunctional monomer. The unit consists of 0.05 to 0.4% by mass.
The crosslinked rubber polymer (II) has a structural unit derived from methyl methacrylate, a structural unit derived from an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, 93.5 to 93.8% by mass, and polyfunctionality. The structural unit derived from the monomer consists of 1.2 to 1.5% by mass.
The thermoplastic polymer (III) is composed of 80 to 100% by mass of a structural unit derived from a methacrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and 0 to 20% by mass of a structural unit derived from an acrylic acid ester.
The amount of the crosslinked polymer (I) is 5 to 40% by mass with respect to the mass of the acrylic multilayer polymer.
The amount of the crosslinked rubber polymer (II) is 20 to 55% by mass with respect to the mass of the acrylic multilayer polymer.
The amount of the thermoplastic polymer (III) is 40 to 75% by mass with respect to the mass of the acrylic multilayer polymer.
The total mass of the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) and the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) is the crosslinked polymer (I) and the crosslinked. The mass of the acetone-soluble component contained in the methacrylic resin composition is y mass% with respect to the mass of the methacrylic resin composition, which is x mass% with respect to the total mass of the rubber polymer (II), and the crosslinked elastic material. When the average diameter of the layer is d nanometers, the value calculated by the formula: x · d / y is 1.0 or more and 3.0 or less.
d is 60-110,
Methacrylic resin composition. The methacrylic resin composition according to claim 1, wherein the acetone-soluble component contained in the methacrylic resin composition has a ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of 2.3 to 3.0. The ratio of the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) is 0.05 to 0. The methacrylic resin composition according to claim 1 or 2, which is .25. The methacrylic resin composition according to any one of claims 1 to 3, wherein the amount of the thermoplastic resin is 5 to 40 parts by mass with respect to 100 parts by mass of the acrylic multilayer polymer. The methacrylic resin composition according to any one of claims 1 to 4, wherein the acrylic multilayer polymer has a graft ratio of 33 to 50% by mass. The methacrylic resin composition according to any one of claims 1 to 6, further comprising an ultraviolet absorber. A film comprising the methacrylic resin composition according to any one of claims 1 to 6.

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