JP2019006865A - Methacrylic resin composition - Google Patents

Abstract

To provide a methacrylic resin composition that has low haze and is excellent in ductility, film formability and stress whitening resistance and to provide a film comprising a methacrylic resin composition.SOLUTION: The methacrylic resin composition contains: 1 to 45 pts.mass of a thermoplastic resin composed of 60 mass% or more of a structural unit derived from methyl methacrylate and 40 mass% or less of a structural unit derived from a monofunctional monomer other than methyl methacrylate; and 100 pts.mass of an acrylic multilayer polymer composed of an outer layer comprising a thermoplastic polymer (III) and a layer of a crosslinked elastic body which has an intermediate layer comprising a crosslinked rubber polymer (II) and an inner layer comprising a crosslinked polymer (I) and contacted and covered with the intermediate layer and which is contacted and covered with the outer layer.SELECTED DRAWING: None

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 resistance.

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, Patent Document 1 discloses that a part of a methacrylic ester copolymer is grafted to acrylate cross-linked elastic particles, and a reduced viscosity of methyl ethyl ketone soluble component is 0.2 to 0.8 dl / g. A methacrylic resin composition is disclosed.

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

  Patent Document 3 discloses that methyl methacrylate is 80 to 99.95% by mass, acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms is 0 to 19.95% by mass, and crosslinkable monomer is 0.05. A core comprising polymer (III) obtained by polymerizing ˜2% by mass, an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, and an aromatic vinyl monomer An inner shell containing a crosslinked rubber polymer (I) obtained by polymerizing 1 to 19% by mass of a polymer 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 1 to 8 alkyl groups. Resin containing crosslinked rubber particle component It discloses a Narubutsu.

  In Patent Document 4, a monomer having an alkyl methacrylate 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 alkyl acrylate 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 formed by molding an outermost layer polymer having a structure of one layer or two or more layers. An acrylic resin composition is disclosed.

  Such blending of an acrylic crosslinked rubber polymer with a methacrylic resin may improve ductility, while lowering hardness and film forming property.

JP 2003-128734 A JP 2004-137298 A JP, 2006-186081, A JP 2006-143785 A

  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 resistance.

  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 comprising 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; A methacrylic resin composition comprising an outer layer composed of a combination (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 layer of the cross-linked elastic body has an intermediate layer made of the cross-linked rubber polymer (II), and an inner layer made of the cross-linked polymer (I) and covered with the intermediate layer,
The crosslinked polymer (I) is composed of 40 to 98.5 mass% of structural units derived from methyl methacrylate, 1 to 59.5 mass% of structural units derived from a monofunctional monomer other than methyl methacrylate, and polyfunctional. Consisting of 0.05 to 0.4 mass% of structural units derived from monomers,
The crosslinked rubber polymer (II) is composed of a structural unit derived from an alkyl acrylate ester having an alkyl group having 1 to 8 carbon atoms and / or a structural unit derived from a conjugated diene, 98.3 to 99% by mass, and a polyfunctional monomer. It consists of 1 to 1.7% by mass of structural units derived from a monomer,
The thermoplastic polymer (III) has a structure derived from a monofunctional monomer other than 80 to 100% by mass of a structural unit derived from an alkyl methacrylate having an alkyl group having 1 to 8 carbon atoms and the alkyl methacrylate. 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 same as that of the crosslinked polymer (I) and the crosslinked polymer. It is x mass% with respect to the total mass of the rubber polymer (II), and 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. 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,
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. object.
[3] The ratio of the mass of the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) 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 a graft ratio of the acrylic multilayer polymer is 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 [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 electric parts, vehicle parts, optical parts, ornaments, signs, building materials, and the like. The film of this invention is excellent in the uniformity of thickness, and is excellent in the lamination property to another member. For example, the film of the present invention does not whiten and is excellent in flexibility even if it is subjected to bending or the like after being laminated with a vinyl chloride film.

  The reason why the methacrylic resin composition of the present invention has the above-mentioned effects is not clear, but the crosslinked polymer (I) suppresses deformation of the crosslinked rubber polymer (II) during melt flow or plastic deformation. Therefore, it is estimated that stress whitening in the methacrylic resin composition is suppressed. Further, it is presumed that the crosslinked polymer (I) contributes to improvement of melt moldability of the methacrylic resin composition by suppressing gelation. By controlling the flexibility of the cross-linked polymer (I) and the cross-linked rubber polymer (II) by controlling the amount of the polyfunctional monomer, etc., it contributes to improving the 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 methacryl resin composition of this invention.

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

  The methacrylic resin composition of the present invention comprises 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 cross-linked elastic layer 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 the polymer which consists of. It is preferable that the thermoplastic polymer (III) does not contain a structural unit derived from a polyfunctional monomer.

  The amount of the structural unit derived from the alkyl methacrylate 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 to 95% by mass.

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

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 relative to the mass of the thermoplastic polymer (III). %, Preferably 5 to 15% by mass.
Monofunctional monomers other than methacrylic acid C1-8 alkyl esters include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and propyl acrylate; styrene, p-methylstyrene And aromatic vinyl compounds such as α-methylstyrene; maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide, and N-o-chlorophenylmaleimide.

  The outer layer may be a single layer composed of one kind of thermoplastic polymer (III) or a multilayer composed of two or more kinds of thermoplastic polymers (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 layer of the crosslinked elastic body has an intermediate layer made of the crosslinked rubber polymer (II) and an inner layer made of the crosslinked polymer (I) and covered with the intermediate layer. In the crosslinked elastic body layer, the inner layer and the intermediate layer preferably form a core and a shell.

  Crosslinked polymer (I) consists 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 with respect to the mass of the crosslinked polymer (I), preferably It is 5-55 mass%.
Monofunctional monomers other than methyl methacrylate include methacrylic acid esters other than methyl methacrylate such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid 2 -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 N-o-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% with respect to the mass of the crosslinked polymer (I). It is -0.3 mass%.
Polyfunctional monomers include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, triallyl Examples include isocyanurate.

  The inner layer may be a single layer made of one kind of cross-linked polymer (I) or a multi-layer made of two or more kinds of cross-linked 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 2 functions in order to control the flexibility of the layer of the crosslinked elastic body and to store a low molecular weight additive such as an ultraviolet absorber. A multilayer composed of at least one kind of crosslinked polymer (I) is preferred.

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

  Examples of the alkyl acrylate 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 and isoprene.

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 mass%, More preferably, it is 1.3-1.5 mass%.
Polyfunctional monomers include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, triallyl Examples include isocyanurate.

  From the viewpoint of improving flex resistance, the structural unit derived from the polyfunctional monomer in the crosslinked polymer (I) with respect to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) The mass ratio 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 composed of one kind of crosslinked rubber polymer (II), or may be a multilayer composed of two or more kinds of crosslinked rubber polymers (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.

  The cross-linked polymer (I) constituting the inner layer and the cross-linked rubber polymer (II) constituting the intermediate layer preferably have molecular chains connected by graft bonding. The crosslinked rubber polymer (II) constituting the intermediate layer and the thermoplastic polymer (III) constituting the outer layer preferably have molecular chains connected by graft bonding. The graft bond is generated by a polymerization method (graft polymerization method) that includes a substituent bonded to the main chain of a completed polymer as a reaction active site and newly extending a branch portion therefrom. A bond connecting the main chain and the branch part.

In the acrylic multilayer polymer used in the present invention, the average diameter (d) of the layer of the crosslinked elastic body is preferably 60 to 110 nm, more preferably 65 to 105 nm, and still more 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 methacrylic resin composition is mold size 50 mm × 120 mm, press temperature 250 ° C., preheating time 3 minutes, press pressure 50 kg / cm ² , press time 30 seconds, cooling temperature 20 ° C., cooling Is formed 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 in a direction parallel to the long side at −100 ° C. to obtain a flake having a thickness of 40 nm, and this flake is dyed with ruthenium. The dyed thin piece is observed with a scanning transmission electron microscope (JSM7600F, manufactured by JEOL Ltd.) at an acceleration voltage of 25 kV, and a photograph is taken. After measuring the minor axis and major axis of the ruthenium-stained portion (section exposed portion of the layer of the crosslinked elastic body), (minor axis + major axis) / 2 is the diameter of the layer of the crosslinked elastic body, and measuring 20 or more, The number average value (average diameter) is calculated.

  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 further preferably 40 to 45% by mass. As the graft ratio decreases, the flexibility of the crosslinked elastic body layer tends to improve, and the tensile elongation and flex resistance tend to improve. As the graft ratio increases, the elasticity of the crosslinked elastic body layer 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 employed in 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 with respect to the mass of the crosslinked rubber polymer (II). More preferably, the content is 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 total mass of the crosslinked polymer (I) and the crosslinked rubber polymer (II) to the mass w ₁ of the acetone-insoluble component in the acrylic multilayer polymer and the mass w ₀ of the acrylic multilayer polymer. From this, the following formula is used.
Graft rate = 100 × [w ₁ −w ₀ × R] / [w ₀ × R]

The acrylic multilayer polymer is not particularly limited depending on the production method. For example, emulsion polymerization can be exemplified.
In the case of emulsion polymerization, for example, the monomer (i) for constituting the crosslinked polymer (I) is emulsion-polymerized to obtain a latex containing the crosslinked polymer (I), and the crosslinked rubber polymer ( Add monomer (ii) to constitute II) and seed emulsion polymerize monomer (ii) to obtain a latex containing crosslinked polymer (I) and crosslinked rubber polymer (II). Further, a monomer (iii) for constituting the thermoplastic polymer (III) is added thereto, and the monomer (iii) is subjected to seed emulsion polymerization 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 performed on the surface of seed particles. Seed emulsion polymerization is preferably used to obtain core-shell structured polymer particles.

  The polymerization initiator used in emulsion polymerization and 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 comprising inorganic initiators combined with sulfites or thiosulfates; organic peroxides The redox initiator etc. which combine ferrous salt or sodium sulfoxylate etc. can be mentioned. The polymerization initiator may be added to the reaction system all together at the start of the 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.

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

  The usage-amount of a polymerization initiator and an emulsifier can be suitably set so that the average particle diameter (D) of the acryl-type multilayer polymer contained in latex may become a desired range. The amount of the emulsifier used varies depending on the type of the emulsifier. For example, it is preferably 0.5 to 3 parts by mass, more preferably 100 parts by mass relative to the total amount of monomers for producing the acrylic multilayer polymer. Is 1 to 2 parts by mass.

The average particle diameter (D) of the acrylic multilayer polymer contained in the latex is preferably 80 nm or more and 150 nm or less, more preferably 90 nm or more and 120 nm or less. When the average particle diameter D of the acrylic multilayer polymer is too small, the viscosity of the latex tends to increase. When the average particle diameter D of the acrylic multilayer polymer is too large, the stress whitening resistance tends to decrease.
The average particle diameter 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 deposited on the dried product, which is observed with a scanning transmission electron microscope (manufactured by JEOL Ltd., JSM7600F) 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 performed in one polymerization tank, The polymerization tank may be changed sequentially for each 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). In the present invention, it is preferable to perform each polymerization sequentially in one polymerization tank. Moreover, 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 monomer (i), seed emulsion polymerization of monomer (ii) and seed emulsion polymerization of monomer (iii), 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 ultraviolet absorber is introduced into the molecular chain of the acrylic multilayer polymer, and the ultraviolet resistance of the acrylic multilayer polymer is improved. The addition amount of the reactive ultraviolet absorber is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the total amount of monomers used for the production of the acrylic multilayer polymer.

  Chain transfer agents can be used in each polymerization to control molecular weight. The chain transfer agent used for each polymerization is not particularly limited. Examples of chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan; xanthogen disulfides such as dimethylxanthogen disulfide and diethylxanthogen disulfide; tetrathiuram disulfide And thiuram disulfides such as halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide. 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 chain transfer agent used in each polymerization varies depending on the amount of polymerization initiator used in the polymerization. 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 coagulated. The latex can be coagulated by a known method. Examples of the coagulation method include a freeze coagulation method, a salting out coagulation method, and an acid precipitation coagulation method. Of these, the freeze coagulation method that does not require the addition of a coagulant that becomes an impurity, or the salting out coagulation method that can be washed is preferable because a coagulated product with less impurities can be obtained. Instead of latex coagulation, latex spray drying may be employed. Before the latex is coagulated or spray-dried, it is preferable to filter the latex with a wire mesh having an opening of 50 μm or less in order to remove foreign substances.

  The slurry obtained by coagulation is washed as necessary and then dehydrated. It is preferable to repeatedly perform washing and dehydration so that the properties of the acrylic multilayer polymer are within a desired range. By washing and dehydrating the slurry, water-soluble components such as emulsifiers and catalysts can be removed from the slurry. The slurry can be washed and dehydrated by, for example, a filter press, a belt press, a gina centrifuge, a screw decanter centrifuge, or the like. It is preferable to use a decanter type centrifugal dehydrator from the viewpoint of productivity and washing efficiency. The slurry is preferably washed and dehydrated at least twice. As the number of washing and dehydration increases, the remaining amount of water-soluble components decreases. However, from the viewpoint of productivity, the number of washing and dehydration is preferably 3 times or less.

  The dehydration is performed 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 performed 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 with an average residence time, preferably 0.5 to 5 hours, more preferably 1 to 3 hours. The lower the water content after dehydration and drying, the higher the warm water whitening resistance and the boiling water whitening resistance tend to be improved.

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

  Monofunctional monomers other than methyl methacrylate include methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, benzyl acrylate Acrylic acid ester monomers such as ethyl methacrylate, butyl methacrylate, propyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid esters other than methyl methacrylate such as benzyl methacrylate; vinyl acetate, Aromatic vinyl compounds such as styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, vinylnaphthalene; ethylenic unsaturation such as acrylonitrile and methacrylonitrile Tolyl; acrylic acid, methacrylic acid, alpha, such as crotonic acid, beta-unsaturated carboxylic acid; N- ethylmaleimide, and the like maleimide compounds such N- cyclohexyl maleimide. Of these, acrylic acid alkyl esters having 1 to 6 carbon atoms in the alkyl group are preferred. Monofunctional monomers 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, and further preferably 105 ° C. or higher. The thermoplastic resin has a melt flow rate at 230 ° C. under a load of 3.8 kg, preferably 0.5 to 20 g / 10 min, more preferably 0.8 to 10 g / 10 min.

  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 should be set so that the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of acetone-soluble matter contained in the methacrylic resin composition falls within a desired range. Is preferred.

The thermoplastic resin is not particularly limited by its production method. For example, it can be obtained by performing a known polymerization reaction such as a radical polymerization reaction or an anionic polymerization reaction by a known polymerization method such as a bulk 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. Moreover, you may use the methacryl resin prescribed | regulated to ISO 8257-1.
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, further preferably 10 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, anti-aging agents, plasticizers, polymer processing aids, lubricants, dyes, pigments, etc., 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 additive for resin may be added at the time of resin melting, may be dry blended with resin pellets, or may be added by a masterbatch method.

The polymer processing aid is a polymer compound composed of 60% by mass or more of structural units derived from methyl methacrylate and 40% by mass or less of structural units derived from vinyl monomers other than methyl methacrylate. Examples of the vinyl 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 And maleimide compounds such as N-cyclohexylmaleimide and N-o-chlorophenylmaleimide. The intrinsic viscosity of the polymer processing aid is preferably 3 to 6 dl / g. When the intrinsic viscosity is within this range, the effect of improving the film forming property tends to be high.
As the polymer processing aid, commercially available products can 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, succinic anilides, malonic esters, formamidines, and the like. These may be used alone or in combination of two or more. Among these, benzotriazoles (compounds having a benzotriazole skeleton) and triazines (compounds having a triazine skeleton) are preferable. Benzotriazoles or triazines have a high effect of suppressing resin degradation (for example, yellowing) due to ultraviolet rays.

  Examples of benzotriazoles include 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (manufactured by BASF; trade name TINUVIN329), 2- (2H- Benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name TINUVIN234), 2,2′-methylenebis [6- (2H-benzotriazole-2 -Yl) -4-tert-octylphenol] (manufactured by ADEKA; LA-31), 2- (5-octylthio-2H-benzotriazol-2-yl) -6-tert-butyl-4-methylphenol 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. Certain hydroxyphenyltriazine-based ultraviolet absorbers (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, Inc .; trade name “Sandyuboa VSU”).

  The methacrylic resin composition of the present invention is a 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 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 average diameter of the crosslinked elastic body layer 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. If the value calculated by the formula: 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.

  In the methacrylic resin composition of the present invention, the amount of the crosslinked elastic body relative to the amount of the methacrylic resin composition is preferably from the viewpoint of achieving both improvement in ductility, folding resistance and tear strength, and improvement in film forming property. It is 20-40 mass%, More preferably, it is 25-35 mass%, More preferably, it is 26-30 mass%.

  From the viewpoint of achieving both improvement in ductility, folding resistance and tear strength, and improvement in film forming property, the amount of acetone-soluble component contained in the methacrylic resin composition is preferably relative to the methacrylic resin composition. It is 48-60 mass%, Preferably it is 49-59 mass%, More preferably, it is 49-58 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 stirred at room temperature for 24 hours. The obtained solution is put into a centrifuge tube and centrifuged at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then removed by decantation, leaving insolubles at the bottom of the settling tube. Acetone is added to the settling tube and stirred. Centrifugation is performed at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then removed by decantation. Again, add acetone to the settling tube and stir. Centrifugation is performed at 5 ° C. and 20000 rpm for 120 minutes. The supernatant is then removed by decantation. The insoluble matter is removed from the bottom of the settling tube, dried at 80 ° C., and its mass w1 is measured. The amount of acetone soluble matter 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 acetone-soluble component has a weight-average molecular weight ratio (Mw / Mn) to a number-average molecular weight of preferably 2.3 to 3.0 from the viewpoint of achieving both improved film-forming properties and improved warm water whitening resistance. More preferably, it is 2.4-2.8, More preferably, it is 2.43-2.7. As Mw / Mn of acetone-soluble component increases, the film forming property tends to improve. As the Mw / Mn of acetone-soluble component decreases, the resistance to warm water whitening tends to improve.

Since the methacrylic resin composition of the present invention is excellent in adhesiveness with a thermoplastic polymer resin, a laminate having a layer composed of the methacrylic resin composition of the present invention and a layer composed of a thermoplastic polymer resin, preferably Is suitable for the production of laminated films. The laminate is not particularly limited by its production method. For example, a method for producing a laminate comprising separately melting and coextrusion molding the methacrylic resin composition of the present invention and a thermoplastic polymer resin, and a molded body made of a thermoplastic polymer resin, such as a film or sheet A method for producing a laminate comprising press molding, coating extrusion molding, insert molding or in-mold molding of the methacrylic resin composition of the present invention on a plate, etc., a molded article comprising the methacrylic resin composition of the present invention, for example, , Film, sheet, plate, etc., thermoplastic polymer resin, press molding, coating extrusion molding, insert molding or in-mold molding, a method for producing a laminate, and a molded body comprising the methacrylic resin composition of the present invention And a method for producing a laminate including welding, bonding, pressure bonding, and the like, and a molded body made of a thermoplastic polymer resin. It can be.
The thermoplastic polymer resins that can be used in the laminate are polycarbonate polymers, vinyl chloride polymers, vinylidene fluoride polymers, methacrylic resins, ABS resins, AES resins, AS resins, and the aforementioned thermoplastic resins. Examples thereof include resins.

  The methacrylic resin composition of the present invention can be applied to various uses. For example, billboard parts such as advertising towers, stand signboards, sleeve signboards, billboard signs, and rooftop signs; display parts such as showcases, partition plates, and store displays; fluorescent lamp covers, mood lighting covers, lamp shades, light ceilings, and light walls Lighting parts such as chandeliers; interior parts such as pendants and mirrors; building parts such as doors, domes, safety window glass, partitions, staircases, balconies, roofs of leisure buildings, sashes, kitchen doors, doors; Aircraft windshield, pilot visor, motorcycle, motorboat windshield, bus shading plate, automotive side visor, rear visor, head wing, headlight cover and other parts related to transport equipment; sound image nameplate, stereo cover, TV protection mask, automatic Electronic equipment parts such as display covers for vending machines Medical equipment parts such as incubators and X-ray parts; equipment-related parts such as machine covers, instrument covers, experimental devices, rulers, dials, observation windows; light guide plates and films for display devices, light guide plates for backlights, Optical parts such as films, LCD protective plates, Fresnel lenses, lenticular lenses, front plates of various displays, diffusers and reflectors; traffic-related parts such as road signs, guide plates, curved mirrors and sound barriers; automotive interior surfaces Materials, film materials such as mobile phone surface materials and marking films; members for household appliances such as canopy materials and control panels for washing machines, top panels for rice cookers; other greenhouses, large aquariums, box aquariums, clock panels, List bathtubs, sanitary, desk mats, game parts, toys, masks for facial protection when welding, etc. Can.

The methacrylic resin composition of the present invention is excellent in transparency, processability, and the bleeding out of the UV absorber is suppressed, for example, indoor and outdoor building material surface layers such as sashes, doors, kitchen doors, various covers, Various terminal boards, printed wiring boards, speakers, microscopes, binoculars, cameras, watches, and other optical equipment, and video / optical recording / optical communication / information equipment related parts such as cameras, VTRs, projection TVs, Filters, prisms, Fresnel lenses, protective films for various optical disks (VD, CD, DVD, MD, LD, etc.) substrates, optical switches, optical connectors, liquid crystal displays, light guide films and sheets for liquid crystal displays, flat panel displays, flat panels Light guide films and sheets for displays, plasma displays, Light guide film / sheet for laser display, light guide film / sheet for electronic paper, retardation film / sheet, polarizing film / sheet, polarizing plate protective film / sheet, polarizer protective film / sheet, wavelength plate, light diffusion film / Sheet, prism film / sheet, reflective film / sheet, anti-reflection film / sheet, viewing angle widening film / sheet, anti-glare film / sheet, brightness enhancement film / sheet, display element substrate for liquid crystal and electroluminescence, touch panel, touch panel It can be suitably applied to applications such as a light guide film / sheet for use, a spacer between various front plates and various modules.
Specifically, for example, various liquid crystal display elements such as mobile phones, digital information terminals, pagers, navigation, in-vehicle liquid crystal displays, liquid crystal monitors, light control panels, displays for OA devices, displays for AV devices, and electroluminescence displays It can be used for an element or a touch panel. In addition, from the point of being excellent in weather resistance, for example, building interior and exterior members, curtain walls, roof members, roofing materials, window members, gutters, exteriors, wall materials, flooring materials, construction materials, The present invention is particularly preferably applicable to known building materials such as road construction members, retroreflective films / sheets, agricultural films / sheets, lighting covers, signboards, and translucent sound insulation walls.

  The methacrylic resin composition of the present invention can be applied to a solar cell surface protective film, a solar cell sealing film, a solar cell back surface protective film, a solar cell base 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 method is preferred. According to the extrusion molding method, a film having improved toughness, excellent handleability, and excellent balance between toughness, surface hardness and rigidity can be obtained. The temperature of the resin discharged from the extruder is preferably set to 160 to 270 ° C, more preferably 220 to 260 ° C.

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

  Moreover, it is preferable that the surface temperature of a mirror surface roll or a mirror surface belt is 130 degrees C or less. The pair of mirror rolls or mirror belts preferably have at least one surface temperature of 60 ° C. or higher. When such a surface temperature is set, the resin discharged from the extruder can be cooled at a speed faster than natural cooling, and a film having excellent surface smoothness and low haze can be easily produced.

  The film of the present invention may be subjected to a stretching treatment. By the stretching treatment, a film that has high mechanical strength and is difficult 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 from 100 to 200 ° C, more preferably from 120 to 160 ° C, from the viewpoint that the film can be stretched uniformly and a high-strength film can be obtained. Stretching is usually performed at 100 to 5000% / min on a length basis. The stretching is preferably performed so that the area ratio is 1.5 to 8 times. A film with less heat shrinkage can be obtained by heat setting after stretching.

  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 still more preferably 15 to 75 μm. Generally, the thinner the film is, the lower the ultraviolet absorbing ability. The methacrylic resin composition of the present invention is less likely to bleed out even when a large amount of an ultraviolet absorber is added, so that 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 formability compared to a film formed of methacrylic resin alone, and the thickness unevenness is small at a thin thickness. In addition, it is excellent in stress whitening resistance and does not whiten when bent.

The film of the present invention has high transparency, high heat resistance, and even during molding at high temperature, the occurrence of mold stains, bleeding out, etc. is suppressed, and the occurrence of problems due to transpiration of ultraviolet absorbers can be reduced. In addition, because it can be made thin, a polarizer protective film, a retardation film, a liquid crystal protective plate, a surface material for a portable information terminal, a display window protective film for a portable information terminal, a light guide film, silver nanowires and carbon nanotubes on the surface It is suitable for coated transparent conductive films, front plate applications for various displays, and the like. In particular, since the film of the present invention has a small retardation, it is suitable for a polarizer protective film.
The film of the present invention has high transparency and processability, and even if a large amount of an ultraviolet absorber is added, it is difficult for bleeding out to occur. Therefore, a film for building materials, a retroreflective film, an IR cut film, a crime prevention film, a scattering prevention film , Decorative film, metal decorative film, solar cell backsheet, flexible solar cell front sheet, shrink film, in-mold label film, gas barrier film base 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 antiglare layer, an antireflection layer, an antisticking layer, a light diffusion layer, an antiglare layer, an antistatic layer, an antifouling layer, a slippery layer, and a gas barrier layer.

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

Abbreviations such as monomers 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-benzotriazol-2-yl)- 4-t-octylphenol] (manufactured by ADEKA; LA-31
B1: Thermoplastic resin (methacrylic resin Kuraray Parapet ^TM EH1000)
B2: Thermoplastic resin (methacrylic resin Kuraray Parapet ^TM HR1000L)
B3: Thermoplastic resin (methacrylic resin Kuraray Parapet ^TM HR-G1000)

  The physical properties of the acrylic multilayer polymers obtained in the 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 is mold size 50 mm × 120 mm, press temperature 250 ° C., preheating time 3 minutes, press pressure 50 kg / cm ² , press time 30 seconds, cooling temperature 20 ° C., 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 in a direction parallel to the long side at −100 ° C. to obtain a flake having a thickness of 40 nm. The flakes were dyed with ruthenium. The dyed thin pieces 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 micron bar at the bottom white line of the photograph represents 100 nm). After measuring the minor axis and major axis of the ruthenium-stained portion (section exposed portion of the layer of the crosslinked elastic body), (minor axis + major axis) / 2 is the diameter of the layer of the crosslinked elastic body, and measuring 20 or more, The number average value (average diameter d) was calculated.

[Acetone soluble content]
2 g (w0) of the accurately weighed methacrylic resin composition was added to 100 ml of acetone and stirred at room temperature for 24 hours. The obtained liquid was put into a centrifuge tube with 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 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 left at the bottom was placed in a vacuum dryer at 50 ° C. to 400 torr for 2 hours and then dried at 80 ° C. to 760 torr for 8 hours. The mass of the dried sediment (acetone insoluble matter) and the centrifuge tube was measured, and the mass of the acetone insoluble matter (w1) was calculated by subtracting the mass of the centrifuge tube from that value. The acetone-soluble content (% by mass) was calculated by the formula: 100 × (w0−w1) / w0.
In addition, acetone separated from the supernatant liquid (supernatant liquid (1) and supernatant liquid (2)) separated as described above is removed at 50 ° C. under reduced pressure using a rotary evaporator, and the solid residue is dried at 80 ° C. Got.

[Graft ratio]
About 2 g of the acrylic multilayer polymer was precisely weighed (w ₀ ) and dissolved by being immersed in 100 g of acetone at 23 ° C. for 24 hours. Then separated into acetone-insoluble matter and acetone-soluble matter by centrifugation, obtaining a dry acetone insolubles mass (w _1), respectively. Further, it is calculated from the ratio R of the total mass of the crosslinked polymer (I) and the crosslinked rubber polymer (II) with respect to the mass w ₀ of the acrylic multilayer polymer by the following formula.
Graft rate = 100 × [w ₁ −w ₀ × R] / [w ₀ × R]

[Molecular weight of acetone-soluble matter]
6 mg of acetone-soluble component was dissolved in 10 ml of tetrahydrofuran to obtain a solution. By measuring the chromatogram under the following conditions by gel permeation chromatography (GPC) and converting it to the molecular weight of standard polymethyl methacrylate, the weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw) / Mn).
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 earlier retention time, and the slope of the peak on the low molecular weight side is negative when viewed from the earlier retention time. A line connecting points that change from zero to zero.
GPC device: manufactured by Tosoh Corporation, HLC-8320
Detector: Differential refractive index detector Column: TSKgel SuperMultipore HZM-M manufactured by Tosoh Corporation and Super HZ4000 connected in series were used.
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 ml / min Column temperature: 40 ° C
Calibration curve: Prepared using data of 11 kinds of standard polymethyl methacrylate.

  The effect exhibited by the methacrylic resin compositions obtained in Examples and Comparative Examples was evaluated as follows.

[Film-forming properties]
The methacrylic resin composition was dried at 80 ° C. for 12 hours. Thereafter, the methacrylic resin composition was extruded at a extrusion temperature of 250 ° C., a die temperature of 250 ° C., and a die lip opening of 0.6 mm in a single screw extruder with a 65φ vent provided with a coat hanger die having a die width of 400 mm. Extrusion was performed at V0, and a metal roll having a roll temperature of 80 ° C. was wound and cooled at a winding speed Vw to obtain a film having a thickness of 50 μm.
About the obtained film, thickness of 20 points was measured at 50 mm intervals in the MD direction, and a standard deviation, an average value, and a coefficient of variation [= (standard deviation / average value) × 100] were calculated from the measured values. A draft value (= Vw / V0) at which the coefficient of variation was 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 the small piece was measured using a haze meter MH-150 manufactured by Murakami Color Research Laboratory.

[Ductility]
The film was punched out to obtain a JIS K 7127 (ISO 572-3) 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 direction of extrusion (MD) and the direction perpendicular to the direction (TD). The tensile elongation was calculated by the formula: tensile elongation (%) = (elongation just before breaking / distance between chucks) × 100. The larger the tensile elongation, the higher the ductility.

[Stress whitening resistance]
The piece of the test piece broken in the tensile elongation measurement test was visually observed.
The case where the entire surface of the piece was whitened was rated as “C”, the case where only the fractured portion was whitened as “B”, and the case where there was no whitened portion as “A”.

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

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

  Next, 0.5 part of a 3% aqueous solution of potassium persulfate was added to the reactor and stirred for 5 minutes. Thereafter, 341.1 parts of a mixture (iii) consisting of 87.2% MMA, 12.5% BA, and 0.3% n-OM was added continuously over 100 minutes. After completion of the addition, a polymerization reaction was further performed 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 diameter of 100 nm.

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

<Production Example 2: Production of acrylic multilayer polymer A2>
A reactor equipped with a stirrer, thermometer, nitrogen gas inlet tube, monomer inlet tube and reflux condenser was charged with 1050 parts of deionized water, 1 part of sodium dodecylbenzenesulfonate and 0.05 part of sodium carbonate, and reacted. The inside of the vessel was sufficiently replaced with nitrogen gas to make it substantially free of oxygen. The temperature in the reactor was 80 ° C. To this, 0.1 part of a 3% aqueous solution of potassium persulfate was added and stirred for 5 minutes. Thereafter, 13.1 parts of a mixture (i) consisting of 90.9% MMA, 9.0% BA, and 0.1% ALMA was continuously added over 10 minutes. After completion of the addition, a polymerization reaction was further performed for 20 minutes. Then 13.1 parts of a 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, a polymerization reaction was further performed for at least 30 minutes so that the polymerization rate was 98% or more.

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

Next, 0.5 part of a 3% aqueous solution of potassium persulfate was added to the reactor and stirred for 5 minutes. Thereafter, 341.1 parts of a 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 performed for at least 60 minutes so that the polymerization rate was 98% or more, thereby obtaining a latex containing an acrylic multilayer polymer A2 having an average particle diameter of 100 nm. The graft ratio was 41% by mass. The number average diameter of the layer 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. The frozen latex was poured into 80 ° C. warm water twice as much as that and dissolved to obtain a slurry. The slurry was held at 80 ° C. for 20 minutes. Then, it 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 were obtained in the same manner as in Production Example 1, except that the mixture (i), mixture (ii) and 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 in the same manner 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, thermometer, nitrogen gas inlet tube, monomer inlet tube and reflux condenser was charged with 1050 parts of deionized water, 1 part of sodium dodecylbenzenesulfonate and 0.05 part of sodium carbonate, and reacted. The inside of the vessel was sufficiently replaced with nitrogen gas to make it substantially free of oxygen. The temperature in the reactor was 80 ° C. Thereto was added 0.5 part of a 3% aqueous solution of potassium persulfate, and the mixture was stirred for 5 minutes. Thereafter, 157.4 parts of a mixture (ii) consisting of MMA 4.9%, BA 93.8% and ALMA 1.3% was continuously added over 40 minutes. After completion of the addition, a polymerization reaction was further performed for at least 30 minutes so that the polymerization rate was 98% or more.

Next, 0.5 part of a 3% aqueous solution of potassium persulfate was added to the reactor and stirred for 5 minutes. Thereafter, 367.3 parts of a 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, a polymerization reaction was further performed for at least 60 minutes so that the polymerization rate was 98% or more, to obtain a latex containing an acrylic multilayer polymer A10 having a number average particle diameter of 100 nm.
Subsequently, the latex containing the acrylic multilayer polymer A10 was frozen at −30 ° C. for 4 hours. The frozen latex was put into 80 ° C. hot water twice as much as that and dissolved to obtain a slurry. The slurry was held at 80 ° C. for 20 minutes. Thereafter, 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 were mixed together and a twin-screw extruder (trade name: KZW20TW-45MG, manufactured by Technobel Co., Ltd.). -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 single screw extruder with a vent, melted and kneaded at an average residence time of 3.5 minutes at 265 ° C., and extruded from a T die into a film. The extruded film-like molten resin was wound around 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)
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 comprising 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 a methacrylic resin composition comprising 100 parts by mass of an acrylic multilayer polymer comprising a layer of a crosslinked elastic body covered in contact with the outer layer,
The layer of the cross-linked elastic body has an intermediate layer made of the cross-linked rubber polymer (II), and an inner layer made of the cross-linked polymer (I) and covered with the intermediate layer,
The crosslinked polymer (I) is composed of 40 to 98.5 mass% of structural units derived from methyl methacrylate, 1 to 59.5 mass% of structural units derived from a monofunctional monomer other than methyl methacrylate, and polyfunctional. Consisting of 0.05 to 0.4 mass% of structural units derived from monomers,
The crosslinked rubber polymer (II) is composed of a structural unit derived from an alkyl acrylate ester having an alkyl group having 1 to 8 carbon atoms and / or a structural unit derived from a conjugated diene, 98.3 to 99% by mass, and a polyfunctional monomer. It consists of 1 to 1.7% by mass of structural units derived from a monomer,
The thermoplastic polymer (III) has a structure derived from a monofunctional monomer other than 80 to 100% by mass of a structural unit derived from an alkyl methacrylate having an alkyl group having 1 to 8 carbon atoms and the alkyl methacrylate. 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 same as that of the crosslinked polymer (I) and the crosslinked polymer. It is x mass% with respect to the total mass of the rubber polymer (II), and 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. 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,
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 polymer (I) to the mass of the structural unit derived from the polyfunctional monomer in the crosslinked rubber polymer (II) 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 a graft ratio of the acrylic multilayer polymer is 33 to 50% by mass.   The methacrylic resin composition according to any one of claims 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.   The film which consists of a methacryl resin composition as described in any one of Claims 1-6.

Images