WO2018084068A1

WO2018084068A1 - Decorative film

Info

Publication number: WO2018084068A1
Application number: PCT/JP2017/038699
Authority: WO
Inventors: 裕一下木場; 広平西野; 哲央野口; 真典松本
Original assignee: デンカ株式会社
Priority date: 2016-11-01
Filing date: 2017-10-26
Publication date: 2018-05-11
Also published as: JPWO2018084068A1; TW201829196A

Abstract

Provided is a decorative film which has excellent appearance, transparency, surface hardness, dimensional stability and impact strength. A decorative film which is obtained by laminating a resin composition layer (a) that is composed of (I) 26-80% by mass of a styrene copolymer and (II) 20-74% by mass of a methacrylic resin on at least one surface of a polycarbonate resin layer (b). The Vicat softening temperature difference between the resin composition and the polycarbonate resin as determined in accordance with JIS K 7206 is within the range of from 0°C to 40°C; and the layer ratio of the resin composition layer (a) to the polycarbonate layer (b) is from 3/97 to 9/91.

Description

Decorative film

The present invention relates to a decorative film excellent in appearance, transparency, surface hardness, dimensional stability, and impact strength.

Automotive interior materials and exterior materials, architectural wall materials and window frames, mobile phones and tablet terminals, personal computers, home appliances, miscellaneous goods, etc. use plastic materials for injection molding suitable for each application. In order to show decorativeness, a decoration technique is used such as when painting is performed, or a film is directly bonded or transferred to an injection-molded plastic material. In the case of painting, there is a problem that the environmental load is large because a volatile organic compound is used, and when the multiple coating is required, the number of work steps increases and the production efficiency deteriorates.

In order to solve such a problem, a decorating technique in which a film is directly bonded or transferred to an injection molded product is used. As decoration techniques, various techniques such as in-mold molding, in-mold transfer, insert mold, and vacuum lamination have been developed. Examples of film materials used for decoration include methacrylic resin, polycarbonate resin, and polyester resin.

Methacrylic resins are excellent in scratch resistance, weather resistance, transparency and color developability, but problems remain in heat resistance, hygroscopicity and strength. Polycarbonate resins are excellent in heat resistance, low moisture absorption, and strength, but problems remain in surface scratch resistance and light resistance. In order to make up for the disadvantages of methacrylic resin and polycarbonate resin and take advantage of the features, for example, the surface of polycarbonate resin layer with low moisture absorption and strength, methacrylic resin with excellent transparency, surface scratch resistance, light resistance, and color development The decorative film which laminated | stacked these is used.

However, when this laminated decorative film is bonded or transferred to an injection-molded product, it is carried out by applying heat, but the difference in heat resistance between the high heat-resistant polycarbonate resin and the low heat-resistant methacrylic resin (processing temperature) There is a problem that cracks, warpage, etc. occur due to the influence of (difference), and that appearance defects occur and the film thickness becomes non-uniform. Further, since the methacrylic resin has high hygroscopicity, there is a problem that warpage is likely to occur as a film.

JP 2014-30985 A JP 2014-34112 A

The present invention is to provide a decorative film excellent in appearance, transparency, surface hardness, dimensional stability, and impact strength.

The gist of the present invention is as follows.
(1) A resin composition layer (a) comprising (I) styrene copolymer 26 to 80% by mass and (II) methacrylic resin 20 to 74% by mass is formed on at least one surface of the polycarbonate resin layer (b). The difference between the resin composition and the polycarbonate resin in terms of Vicat softening temperature determined in accordance with JIS K7206 is within 0 to 40 ° C., and the layer ratio of the resin composition layer (a) to the polycarbonate layer (b) Is a decorative film having a ratio of 3/97 to 9/91.
(2) (I) Styrene copolymer is 45 to 85% by mass of aromatic vinyl monomer unit, 5 to 45% by mass of (meth) acrylic acid ester monomer unit, unsaturated dicarboxylic acid anhydride single amount The decorative film according to (1), comprising a body unit of 10 to 30% by mass and having a Vicat softening temperature of 115 ° C. or higher determined in accordance with JIS K7206.
(3) The decorative film as described in (1) or (2), wherein the styrene copolymer has a saturated water absorption of 1.0% or less obtained in accordance with JIS K7209 .
4. The composition according to claim 1, wherein 5 to 35 parts by mass of (III) graft copolymer is contained with respect to 100 parts by mass in total of (I) styrene copolymer and (II) methacrylic resin. The decorative film as described in one.

A decorative film having excellent appearance, transparency, surface hardness, dimensional stability, and impact strength can be provided.

<Explanation of terms>
In the present specification, for example, the description “A to B” means not less than A but not more than B.

Hereinafter, embodiments of the present invention will be described in detail.

(I) Styrenic copolymer is a copolymer having an aromatic vinyl monomer unit, a (meth) acrylic acid ester monomer unit, an unsaturated dicarboxylic acid anhydride monomer unit, For example, there is a styrene-methyl methacrylate-maleic anhydride copolymer.

Aromatic vinyl monomer units include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, ethyl styrene, p-tert-butyl styrene, α-methyl styrene, α Examples thereof include units derived from styrene monomers such as -methyl-p-methylstyrene. Of these, styrene units are preferred. These aromatic vinyl monomer units may be one type or a combination of two or more types.

Examples of the (meth) acrylic acid ester monomer unit include methyl methacrylate monomers such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, dicyclopentanyl methacrylate, and isobornyl methacrylate, and Examples include units derived from acrylate monomers such as methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-methylhexyl acrylate, 2-ethylhexyl acrylate, and decyl acrylate. Among these, a methyl methacrylate unit is preferable. These (meth) acrylic acid ester monomer units may be one kind or a combination of two or more kinds.

Examples of the unsaturated dicarboxylic acid anhydride monomer unit include units derived from respective anhydride monomers such as maleic acid anhydride, itaconic acid anhydride, citraconic acid anhydride, and aconitic acid anhydride. Among these, maleic anhydride units are preferable. The unsaturated dicarboxylic acid anhydride monomer unit may be one type or a combination of two or more types.

The (I) styrene copolymer is a copolymerizable vinyl monomer other than an aromatic vinyl monomer unit, a (meth) acrylic acid ester monomer unit, and an unsaturated dicarboxylic anhydride monomer unit. A unit of a monomer may be included in the copolymer as long as the effect of the invention is not inhibited, and it is preferably 5% by mass or less. Examples of the copolymerizable vinyl monomer unit include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, vinyl carboxylic acid monomers such as acrylic acid and methacrylic acid, N-methylmaleimide, and N-ethylmaleimide N-alkylmaleimide monomers such as N-butylmaleimide and N-cyclohexylmaleimide, N-arylmaleimide monomers such as N-phenylmaleimide, N-methylphenylmaleimide and N-chlorophenylmaleimide Examples are units derived from the body. Two or more types of copolymerizable vinyl monomer units may be used.

(I) The constituent unit of the styrene copolymer is preferably 45 to 85% by mass of an aromatic vinyl monomer unit, 5 to 45% by mass of a (meth) acrylic acid ester monomer unit, and an unsaturated dicarboxylic acid anhydride. 10 to 30% by mass of monomer units, more preferably 50 to 80% by mass of aromatic vinyl monomer units, 8 to 38% by mass of (meth) acrylate monomer units, and unsaturated dicarboxylic acid anhydride The monomer unit is 12 to 25% by mass.

If the aromatic vinyl monomer unit is 45% by mass or more, low hygroscopicity, thermal stability and molding processability are improved, and if it is 50% by mass or more, further low hygroscopicity, thermal stability and molding process. Improves. If the aromatic vinyl monomer unit is 85% by mass or less, the scratch resistance is improved, and if it is 80% by mass or less, the scratch resistance is further improved.

If the (meth) acrylic acid ester monomer unit is 5% by mass or more, the scratch resistance is good, and if it is 8% by mass or more, the scratch resistance is further good. If the (meth) acrylic acid ester monomer unit is 45% by mass or less, low hygroscopicity, thermal stability and molding processability are improved, and if it is 38% by mass or less, further low hygroscopicity and thermal stability. , Molding processability is improved.

When the unsaturated dicarboxylic acid anhydride monomer unit is 10% by mass or more, the heat resistance is improved, and when it is 12% by mass or more, the heat resistance is further improved. If the unsaturated dicarboxylic acid anhydride monomer unit is 30% by mass or less, thermal stability and molding processability are improved, and if it is 25% by mass or less, thermal stability and molding processability are further improved.

(I) The styrenic copolymer preferably has a Vicat softening temperature of 115 ° C. or higher, more preferably 125 ° C. or higher, as determined in accordance with JIS K7206 at a load of 50 N and a heating rate of 50 ° C./hour. . The higher the Vicat softening temperature, the better the heat resistance, and the greater the effect of imparting heat when blended with a methacrylic resin.

(I) The styrene copolymer preferably has a saturated water absorption of 1.0% or less, more preferably 0.8% or less, determined in accordance with JIS K7209. The lower the saturated water absorption, the lower the hygroscopicity and the greater the effect of suppressing moisture absorption deformation when blended with a methacrylic resin.

(I) The weight average molecular weight (Mw) of the styrene copolymer is preferably 100,000 to 300,000, more preferably 140,000 to 250,000. When the weight average molecular weight (Mw) is smaller than 100,000, the strength is lowered, and when it exceeds 300,000, the moldability is deteriorated. (I) The weight average molecular weight (Mw) of the styrene copolymer is the polymerization temperature in the polymerization step, the type and addition amount of the polymerization initiator, the type and addition amount of the chain transfer agent, the type of solvent used during the polymerization, and The amount can be controlled. The weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC), and is a value measured under the measurement conditions described below.
Device name: SYSTEM-21 Shodex (manufactured by Showa Denko)
Column: 3 series PL gel MIXED-B Temperature: 40 ° C
Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2% by mass
Calibration curve: Prepared using standard polystyrene (PS) (manufactured by PL).

(I) The total light transmittance of 2 mm thickness measured based on ASTM D1003 of the styrene copolymer is preferably 88% or more, more preferably 89% or more, and particularly preferably 90% or more. . If the total light transmittance of 2 mm thickness is 88% or more, the transparency of the resin composition obtained by blending with a methacrylic resin will be good. The total light transmittance is a mirror surface of 90 mm in length, 55 mm in width, and 2 mm in thickness formed using an injection molding machine (IS-50EPN manufactured by Toshiba Machine Co., Ltd.) under molding conditions of a cylinder temperature of 230 ° C and a mold temperature of 40 ° C. The plate is a value measured using a haze meter (NDH-1001DP type manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with ASTM D1003.

(I) A method for producing a styrene copolymer will be described. The polymerization mode is not particularly limited and can be produced by a known method such as solution polymerization or bulk polymerization, but solution polymerization is more preferable. The solvent used in the solution polymerization is preferably non-polymerizable from the viewpoint that a by-product is difficult to produce and that there are few adverse effects. The type of the solvent is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, ethers such as tetrahydrofuran, 1,4-dioxane, toluene, ethylbenzene, xylene, chlorobenzene Aromatic hydrocarbons, etc. are mentioned, but methyl ethyl ketone and methyl isobutyl ketone are preferred from the viewpoint of the solubility of the monomer and copolymer and the ease of solvent recovery. The amount of the solvent added is preferably 10 to 100 parts by mass, and more preferably 30 to 80 parts by mass with respect to 100 parts by mass of the copolymer to be obtained. If it is 10 parts by mass or more, it is suitable for controlling the reaction rate and the polymerization solution viscosity, and if it is 100 parts by mass or less, it is suitable for obtaining a desired weight average molecular weight (Mw).

The polymerization process may be any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method, but the batch polymerization method is suitable for obtaining a desired molecular weight range and transparency.

The polymerization method is not particularly limited, but is preferably a radical polymerization method from the viewpoint that it can be produced with high productivity by a simple process. The polymerization initiator is not particularly limited. For example, dibenzoyl peroxide, t-butylperoxybenzoate, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butylperoxy Known organic compounds such as isopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyacetate, dicumyl peroxide, ethyl-3,3-di- (t-butylperoxy) butyrate Known azo compounds such as peroxides, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethylpropionitrile, azobismethylbutyronitrile, and the like can be used. Two or more of these polymerization initiators can be used in combination. Of these, organic peroxides having a 10-hour half-life temperature of 70 to 110 ° C. are preferably used.

(I) The styrene copolymer preferably has a total light transmittance of 88% or more with a thickness of 2 mm measured based on ASTM D1003. If a copolymer satisfying this condition is obtained, the polymerization procedure is not particularly limited. However, in order to obtain a copolymer having a total light transmittance of 88% or more, the copolymer composition distribution is small. Must be polymerized. Since the aromatic vinyl monomer and unsaturated dicarboxylic acid anhydride monomer have strong alternating copolymerization, it corresponds to the polymerization rate of the aromatic vinyl monomer and the (meth) acrylate monomer. Thus, a method of continuously adding unsaturated dicarboxylic acid anhydride monomers is preferred. The control of the polymerization rate can be adjusted by the polymerization temperature, the polymerization time, and the addition amount of the polymerization initiator. It is preferable to continuously add a polymerization initiator because the polymerization rate can be more easily controlled.

Further, regarding a method for obtaining a copolymer having a weight average molecular weight (Mw) of 100,000 to 300,000, in addition to adjustment of polymerization temperature, polymerization time and polymerization initiator addition amount, addition of solvent and addition of chain transfer agent It can be obtained by adjusting the amount. The chain transfer agent is not particularly limited. For example, a known chain transfer agent such as n-dodecyl mercaptan, t-dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene is used. Can do.

After the polymerization is completed, the polymerization solution is optionally provided with a heat resistant stabilizer such as a hindered phenol compound, a lactone compound, a phosphorus compound, a sulfur compound, a light resistant stabilizer such as a hindered amine compound, a benzotriazole compound, Additives such as lubricants, plasticizers, colorants, antistatic agents and mineral oils may be added. The addition amount is preferably less than 0.2 parts by mass with respect to 100 parts by mass of all monomer units. These additives may be used alone or in combination of two or more.

The method for recovering the (I) styrene copolymer from the polymerization solution is not particularly limited, and a known devolatilization technique can be used. For example, a method of continuously feeding the polymerization liquid to a twin-screw devolatilizing extruder using a gear pump and devolatilizing a polymerization solvent, an unreacted monomer and the like can be mentioned. The devolatilizing component including the polymerization solvent, unreacted monomer, etc. is condensed and recovered using a condenser, etc., and the polymerization solvent can be reused by purifying the condensate in a distillation tower. .

The (II) methacrylic resin is a polymer having a (meth) acrylic acid ester monomer unit, for example, polymethyl methacrylate, and a commercially available general one can be used. Moreover, in this invention, it can have a styrene-type monomer unit further, and a styrene-type monomer unit can be used at 20 mass% or less.

(II) The methacrylic resin may contain a stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant and the like as long as the effects of the present invention are not impaired.

By blending (I) a styrene copolymer with (II) methacrylic resin, (II) an effect of improving the heat resistance of the methacrylic resin and an effect of suppressing hygroscopicity can be imparted.

The blending ratio of the resin composition comprising (I) styrene copolymer and (II) methacrylic resin is (I) styrene copolymer 26 to 80% by mass and (II) methacrylic resin 20 to 74% by mass. Preferably, (I) 30 to 70% by mass of styrene copolymer and (II) 30 to 70% by mass of methacrylic resin, more preferably (I) 35 to 65% by mass of styrene copolymer and (II). The methacrylic resin is 35 to 65% by mass. If it is said mixture ratio, it is excellent in the balance of an external appearance, transparency, surface hardness, dimensional stability, and impact strength.

(III) Graft copolymer may be further added to (I) styrene copolymer and (II) methacrylic resin.

(III) The graft copolymer is a core-shell type graft copolymer comprising a diene rubber copolymer and one or more types of monomer monomer units. For example, a polybutadiene-styrene-methyl methacrylate graft copolymer There is a coalescence, and commercially available general ones can be used.

The decorative film of the present invention may contain 5 to 35 parts by mass of (III) graft copolymer with respect to 100 parts by mass in total of (I) styrene copolymer and (II) methacrylic resin. (III) If the graft copolymer is 5 parts by mass or more, the impact strength is excellent, and if the graft copolymer is 35 parts by mass or less, the balance of appearance, transparency, surface hardness, and dimensional stability is excellent.

The method for obtaining the resin composition is not particularly limited, and a known melt-kneading technique can be used. Examples of the melt-kneading apparatus that can be suitably used include a single screw extruder, a meshing type co-rotating or meshing type counter-rotating twin screw extruder, a screw extruder such as a non- or incomplete meshing type twin screw extruder, a Banbury mixer, There are kneaders and mixing rolls.

A stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, and the like may be blended in the resin composition as long as the effects of the present invention are not impaired.

The polycarbonate resin is a resin in which the joint portion between the monomer units is composed of a carbonate group (—O— (C═O) —O—), and a commercially available general resin can be used. I can do it.

A stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, and the like may be blended with the polycarbonate resin as long as the effects of the present invention are not impaired.

Decorative film refers to plastic materials for injection molding that are used in, for example, automobile interior materials and exterior materials, architectural wall materials and window frames, mobile phones and tablet terminals, personal computers, home appliances, and other housing parts. Thus, it is a film that imparts functions such as designability, decorativeness, and scratch resistance by direct bonding or transfer.

The decorative film of the present invention comprises (I) a resin composition layer (a) comprising 26 to 80% by mass of a styrene copolymer and (II) 20 to 74% by mass of a methacrylic resin, wherein the polycarbonate resin layer (b) It is laminated on at least one surface.

The decorative film of the present invention is based on JIS K7206 of a resin composition and a polycarbonate resin, and the difference in Vicat softening temperature obtained at a load of 50 N and a heating rate of 50 ° C./hour is within 0 to 40 ° C., preferably Within 0-35 ° C. If the difference in Vicat softening temperature is within 0 to 40 ° C., a decorative film having a good appearance and a uniform thickness can be obtained.

In the decorative film of the present invention, when the a / b layer ratio of the resin composition layer (a) and the polycarbonate resin layer (b) is 3/97 to 9/91, the appearance, transparency, surface hardness, dimensional stability The ratio is preferably 6/94 to 9/91, and more preferably 6/94 to 9/91. When the a / b layer ratio is 6/94 to 9/91, the surface hardness of the decorative film is particularly excellent.

The method for obtaining the decorative film of the present invention is not particularly limited, and a known melt coextrusion molding technique can be used. Examples of the melt coextrusion molding that can be suitably used include a feed block system and a multi-die system.

In the decorative film of the present invention, the resin composition layer (a) is laminated on at least one surface of the polycarbonate resin layer (b). Further, the resin composition layer (a) and the polycarbonate resin layer (b ), A multi-layer structure in which a number of layers such as a layer on which a pattern is printed, a thin film layer on which a metal or metal oxide is vapor-deposited, an adhesive layer, an adhesive layer, and a primer layer are laminated.

The decorative film of the present invention is preferably subjected to a cured coating treatment (hard coat) within a range that does not impair the effects of the present invention.

There is no limitation in particular about the decoration molding method using the decorating film of this invention, A well-known decorating technique can be used. For example, there are in-mold molding, in-mold transfer, insert mold, vacuum lamination and the like.

Examples are given below to illustrate the present invention in more detail. However, the present invention is not limited to these examples.

<Production Example of Styrene Copolymer (A-1)>
20% maleic anhydride solution dissolved in methyl isobutyl ketone so that maleic anhydride has a concentration of 20% by mass and methyl so that t-butylperoxy-2-ethylhexanoate becomes 2% by mass. A 2% t-butyl peroxy-2-ethylhexanoate solution diluted in isobutyl ketone was prepared in advance and used for the polymerization. A 120-liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 24 kg of styrene, 10.4 kg of methyl methacrylate, and 38 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, 2.1% / hour of 20% maleic anhydride solution and 375 g / hour of 2% t-butylperoxy-2-ethylhexanoate solution were respectively added. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 8 ° C./hour while maintaining the addition rate of 2.1 kg / hour as it was. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 25.2 kg. After the temperature rise, the polymerization liquid which has been held at 120 ° C. for 1 hour to finish the polymerization is continuously fed to a twin-screw devolatilizing extruder using a gear pump to remove methyl isobutyl ketone and a small amount of unreacted monomer. The styrene copolymer (A-1) in the form of pellets was obtained by performing volatilization treatment and extruding and cutting into strands. The resulting styrene copolymer (A-1) was subjected to composition analysis by C-13 NMR method, and the weight average molecular weight (Mw) was measured with a GPC apparatus. Further, using an injection molding machine (IS-50EPN manufactured by Toshiba Machine Co., Ltd.), a mirror surface plate having a length of 90 mm, a width of 55 mm, and a thickness of 2 mm was injection molded under molding conditions of a cylinder temperature of 230 ° C. and a mold temperature of 40 ° C. to ASTM D1003. Based on this, a total light transmittance of 2 mm thickness was measured using a haze meter (NDH-1001DP type manufactured by Nippon Denshoku Industries Co., Ltd.). Table 1 shows the composition analysis results, the molecular weight measurement results, and the total light transmittance measurement results.

<Production Example of Styrene Copolymer (A-2)>
A 25% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 1.9 kg of a 25% maleic anhydride solution, 11.9 kg of styrene, 2.5 kg of methyl methacrylate, and 11 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, it heated up to 92 degreeC over 40 minutes, stirring. While maintaining the temperature at 92 ° C. after the temperature rise, a 25% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were successively added. The 25% maleic anhydride solution was 2.25 kg / hr from the 4th hour to the start of the addition, 1.73 kg / hr from the 4th to the 7th hour, and 0.86 kg from the 7th to the 10th hour. The addition rate was changed stepwise so that the addition rate was 0.17 kg / hour from 10 hours to 13 hours / hour, and a total of 17.28 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was dispensed at a rate of 0.14 kg / hour from the start of the addition to 7 hours and 0.24 kg / hour from the 7th hour to the 13th hour. The addition speed was changed stepwise so that 2.49 kg in total was added. The polymerization temperature is maintained at 92 ° C. until 7 hours from the start of the addition, and then heated to 116 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 116 ° C. for 1 hour. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A copolymer (A-2) was obtained. With respect to the obtained styrene copolymer (A-2), composition analysis, molecular weight, and total light transmittance were measured in the same manner as in A-1. The measurement results are shown in Table 1.

<Production Example of Styrene Copolymer (A-3)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 1.5 kg of a 20% maleic anhydride solution, 16.8 kg of styrene, 1.6 kg of methyl methacrylate, and 10 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, it heated up to 92 degreeC over 40 minutes, stirring. While maintaining the temperature at 92 ° C. after the temperature rise, a 20% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were each continuously added. The 20% maleic anhydride solution is 2.05 kg / hr from the 4th hour to the start of the addition, 1.65 kg / hr from the 4th to the 7th hour, and 0.83 kg from the 7th to the 10th hour. / Hour, the addition speed was changed stepwise so that the addition speed of 0.13 kg / hour was obtained from the 10th hour to the 13th hour, and a total of 16.03 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was dispensed at a rate of 0.14 kg / hour from the start of the addition to 7 hours and 0.24 kg / hour from the 7th hour to the 13th hour. The addition speed was changed stepwise so that 2.49 kg in total was added. The polymerization temperature is maintained at 92 ° C. until 7 hours from the start of the addition, and then heated to 116 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 116 ° C. for 1 hour. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A copolymer (A-3) was obtained. With respect to the obtained styrene copolymer (A-3), composition analysis, molecular weight, and total light transmittance were measured in the same manner as in A-1. The measurement results are shown in Table 1.

<Example of production of styrene copolymer (A-4)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 2.5 kg of a 20% maleic anhydride solution, 19.8 kg of styrene, 18 kg of methyl methacrylate, and 38 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. The temperature was raised to 92 ° C. over 40 minutes with stirring. While maintaining the temperature at 92 ° C. after the temperature rise, a 20% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were each continuously added. The 20% maleic anhydride solution is 1.85 kg / hour from the 4th hour to the start of the addition, 1.55 kg / hour from the 4th to the 7th hour, and 0.8 kg from the 7th to the 10th hour. The addition rate was changed stepwise so that the addition rate was 0.1 kg / hour from 10 hours to 13 hours / hour, and a total of 14.75 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was dispensed at a rate of 0.14 kg / hour from the start of the addition to 7 hours and 0.24 kg / hour from the 7th hour to the 13th hour. The addition speed was changed stepwise so that 2.49 kg in total was added. The polymerization temperature is maintained at 92 ° C. until 7 hours from the start of the addition, and then heated to 116 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 116 ° C. for 1 hour. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A copolymer (A-4) was obtained. The resulting styrene copolymer (A-4) was measured for composition analysis, molecular weight, and total light transmittance in the same manner as in A-1. The measurement results are shown in Table 1.

<Production Example of Styrene Copolymer (A-5)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 1.3 kg of a 20% maleic anhydride solution, 15.7 kg of styrene, 6.1 kg of methyl methacrylate, and 21 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, it heated up to 93 degreeC over 40 minutes, stirring. While maintaining the temperature at 93 ° C. after the temperature rise, a 20% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were each continuously added. The 20% maleic anhydride solution was 1.85 kg / hr from the 4th hour to the start of the addition, 1.45 kg / hr from the 4th to the 7th hour, and 0.78 kg from the 7th to the 10th hour. The addition rate was changed stepwise so that the addition rate was 0.09 kg / hour from 10 hours to 13 hours / hour, and a total of 14.36 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was added at a rate of 0.16 kg / hour from the start of the addition to 7 hours and 0.25 kg / hour from the 7th hour to the 13th hour. Then, the addition speed was changed stepwise so that 2.62 kg in total was added. The polymerization temperature is maintained at 93 ° C. until 7 hours from the start of the addition, and then heated up to 117 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 117 ° C. for 1 hour for polymerization. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A copolymer (A-5) was obtained. With respect to the obtained styrene copolymer (A-5), composition analysis, molecular weight, and total light transmittance were measured in the same manner as in A-1. The measurement results are shown in Table 1.

<Production Example of Styrene Copolymer (A-6)>
A 25% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120-liter autoclave equipped with a stirrer was charged with 2.5 kg of a 25% maleic anhydride solution, 8.7 kg of styrene, 5.7 kg of methyl methacrylate, and 7 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. Then, it heated up to 92 degreeC over 40 minutes, stirring. While maintaining the temperature at 92 ° C. after the temperature rise, a 25% maleic acid-free aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were successively added. The 25% maleic anhydride solution is 2.5 kg / hr from the 4th hour to the start of the addition, 1.9 kg / hr from the 4th to the 7th hour, and 0.9 kg from the 7th to the 10th hour. The addition rate was changed stepwise so that the addition rate was 0.2 kg / hour from 10 hours to 13 hours / hour, and a total of 19 kg was added. The 2% t-butylperoxy-2-ethylhexanonate solution was dispensed at a rate of 0.12 kg / hour from the start of the addition until the 7th hour and 0.22 kg / hour from the 7th to the 13th hour. The addition speed was changed stepwise so that 2.16 kg in total was added. The polymerization temperature is maintained at 92 ° C. until 7 hours from the start of the addition, and then heated to 116 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 116 ° C. for 1 hour. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A copolymer (A-6) was obtained. With respect to the obtained styrene copolymer (A-6), composition analysis, molecular weight, and total light transmittance were measured in the same manner as in A-1. The measurement results are shown in Table 1.

As the methacrylic resin, “Acrypet VH001” (MFR: 2 g / 10 min, glass transition temperature: 108 ° C.) manufactured by Mitsubishi Rayon Co., Ltd. was used.

As the polycarbonate resin, “Panlite L-1250” (MFR: 8 g / 10 min, glass transition temperature: 150 ° C.) manufactured by Teijin Limited was used.

As the graft copolymer, “Metabrene C-223A” manufactured by Mitsubishi Rayon Co., Ltd. was used.

<Examples and comparative examples>
The styrene copolymer (A-1 to 6) described in the above production example, methacrylic resin, and graft copolymer were mixed in the proportions shown in Tables 2 to 3, and then a twin screw extruder (manufactured by Toshiba Machine Co., Ltd.). Using TEM-35B), the mixture was melt-kneaded at a cylinder temperature of 230 ° C. to obtain a resin composition. The resin composition and the polycarbonate resin were each fed by a feed block method (500 mm wide T-die) using a single screw extruder (SE-65CA manufactured by Toshiba Machine Co., Ltd.). Melt coextrusion was performed at a cylinder temperature of 270 ° C. on the resin side to produce a laminated film having a two-layer structure having a thickness of 100 μm ± 5 μm. At this time, the layer ratio of the resin composition layer (a) to the polycarbonate resin layer (b) (thickness ratio of each layer) was adjusted to the values described in Tables 2 to 3. Various evaluation results are shown in Tables 2 to 3.

(Vicat softening temperature)
Based on JIS K7206, the Vicat softening temperature was measured under the conditions of a load of 50 N and a heating rate of 50 ° C./hour. The difference between the Vicat softening temperature of the resin composition and the polycarbonate resin was 0 to 40 ° C. was accepted.

(Total light transmittance and Haze (cloudiness))
The film was cut into 90 mm length and 90 mm width, and the total light transmittance and Haze were measured using a haze meter (NDH-1001DP type manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with ASTM D1003. A total light transmittance of 88% or more and a haze of 3.0% or less were accepted.

(Pencil hardness)
After the film was cut into 90 mm length and 90 mm width, it was allowed to stand so that the resin composition layer (a) was the upper layer and the polycarbonate resin layer (b) was the lower layer, and JIS K 5600-5-4: 1999 (load 750 g, The pencil hardness was measured using a pencil scratch hardness tester (KT-VF2380 manufactured by Cortec Co., Ltd.). A pencil hardness of H or higher was accepted.

(appearance)
The appearance was evaluated by visually observing 50 samples obtained by cutting the film 90 mm in length and 90 mm in width, and counting the number of samples in which appearance defects such as coloring, bubbles, burn-out contamination, and bumps occurred. The evaluation criteria are as follows.
A: The number of appearance defect samples is 0. ○: The number of appearance defect samples is 1-2. Δ: The number of appearance defect samples is 2-5. ×: The number of appearance defects is 6 or more.

(Warpage amount)
The film was cut to 90 mm in length and 90 mm in width, and then allowed to stand for 72 hours under conditions of temperature 85 ° C. and humidity 85% with an environmental tester (PL-3KPH manufactured by Espec Corp.). Then, the laminated film after the test is placed on a flat glass substrate so as to protrude downward, the gap between each of the four apexes of the laminated film and the glass substrate surface, and the central part (each side of each side of the laminated film). The gap between 4 positions and the glass substrate surface was measured (total of 8 positions measured), and the average value was taken as the amount of warpage. A warp amount of 1 mm or less was regarded as acceptable.

(Drop impact test)
After cutting 30 films in a length of 50 mm and a width of 50 mm, the top and bottom of the film were sandwiched with a ring having an inner diameter of 40 mm, and fixed with clips. Thereafter, a drop impact test was performed in which an iron ball having a diameter of 11 mm and a weight of 5.45 g was dropped from the height of 30 cm onto the top of the film. The evaluation criteria are as follows.
◎: No cracks or cracks occurred in the number of films ○: Cracks or cracks occurred in the number of films 1 to 2 △: Cracks or cracks occurred in the number of films 2 to 5 x: Cracks or cracks occurred 6 or more films

In the examples, a laminated film excellent in appearance, transparency, surface hardness, dimensional stability, and impact strength could be obtained. On the other hand, in the comparative example, any physical property was inferior among the appearance, transparency, surface hardness, dimensional stability, and impact strength.

According to the present invention, the film in which the resin composition layer is laminated on at least one surface of the polycarbonate resin layer is excellent in appearance, transparency, surface hardness, dimensional stability, and impact strength, and is used in automobile interior materials. And exterior materials, architectural wall materials, window frames, mobile phones, tablet terminals, personal computers, home appliances, and other decorative films.

Claims

A resin composition layer (a) comprising (I) 26 to 80% by mass of a styrene copolymer and (II) 20 to 74% by mass of a methacrylic resin is laminated on at least one surface of the polycarbonate resin layer (b). The difference in Vicat softening temperature determined in accordance with JIS K7206 between the resin composition and the polycarbonate resin is within 0 to 40 ° C., and the layer ratio of the resin composition layer (a) to the polycarbonate layer (b) is 3 / A decorative film that is 97-9 / 91.
(I) Styrenic copolymer contains 45 to 85% by weight of aromatic vinyl monomer unit, 5 to 45% by weight of (meth) acrylic acid ester monomer unit, and 10 units of unsaturated dicarboxylic acid anhydride monomer unit. The decorative film according to claim 1, wherein the decorative film has a Vicat softening temperature of 115 ° C or higher determined from -30% by mass in accordance with JIS K7206.
(I) The decorative film according to claim 1 or 2, wherein the styrene copolymer has a saturated water absorption of 1.0% or less determined in accordance with JIS K7209.
The composition according to any one of claims 1 to 3, wherein (III) the graft copolymer is contained in an amount of 5 to 35 parts by mass with respect to a total of 100 parts by mass of (I) the styrene copolymer and (II) methacrylic resin The decorative film described.