JP4836362B2 - Acrylic film and its laminate - Google Patents

Description

（参考例１０）
同様に乳化重合でＭＭＡ９２％、ＢＡ８％の単量体を用いて共重合体を製造した。得られたメタクリル酸エステル系共重合体の還元粘度は０．３６ｄｌ／ｇであった。
【００３２】
（参考例１１）
懸濁重合で製造したＭＭＡ−ＥＡ共重合体（住友化学株式会社製スミペックスＥＸ；ＭＭＡ約９５％、ＥＡ約５％からなる重合体、還元粘度 ０．３０ｄｌ／ｇ）を用いた。
【００３３】
（実施例１〜７及び比較例１〜５）得られた重合体を用い表２に示す樹脂組成物１００部に対し、紫外線吸収剤として、チヌビン１５７７（チバスペシャルケミカル社製）１．５部、及び酸化防止剤としてスミライザーＧＭ（住友化学社製）０．３部を混合し、ベント式押出し機で２２０℃で押出しペレットを得た。得られたペレットをＴダイ押出し機でダイス温度２４０℃で成形し１００μｍ厚みのフィルムを得た。このフィルムを用いて種々の物性を評価した。結果を表２に示した。
【００３４】
【表２】

【００３５】
【発明の効果】
本発明のフィルムが引っ張り強度、破断時伸び、応力白化、透明性、表面硬度及び表面性のバランスよく優れていることがわかる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to specific acrylic films and acrylic film laminates, particularly injection molded articles.
[0002]
[Prior art]
As a method for decorating the surface of plastics, metal products, etc., there are a direct printing method and a transfer method. However, the direct printing method is not suitable for a molded product having a complicated shape, and the transfer method has a problem of high cost. In-mold molding, in which a film such as an acrylic resin is molded by vacuum molding or the like in the previous process, or inserted into an injection mold without molding, and the base resin is injection molded as a method of adding decoration at low cost There is a law. Various acrylic films suitable for this application have been proposed. For example, JP-A-8-323934 describes the reduced viscosity of a plastic polymer, the particle diameter of a rubber-containing polymer, the rubber content, and the like. JP-A-10-279766 and JP-A-10-306192 describe the reduced viscosity of the acrylic polymer and the content of the multilayer structure acrylic polymer. It is described that these films are excellent in surface hardness, transparency, and film formability. However, nothing is described about stress whitening of the film. That is, in this application, when these films are laminated on a molded product having a complicated shape, stress concentrates on corners and the like, so that the film is likely to be whitened, and the commercial value is remarkably lowered.
[0003]
[Problems to be solved by the invention]
Accordingly, the present inventors have intensively studied to develop a film that does not cause stress whitening, and as a result, a resin composed of a multilayer acrylic polymer using a specific acrylic ester rubber elastic body and a methacrylic polymer. The present inventors have found that the composition has little stress whitening, high surface hardness, excellent transparency, excellent weather resistance, large elongation at break, and excellent film formability and surface properties.
[0004]
[Means for Solving the Problems]
The present invention is a resin composition comprising an acrylic graft copolymer (A) containing an acrylic ester rubbery polymer and a methacrylic polymer (B) containing 80% by weight or more of methyl methacrylate,
(1) Content of acrylic ester rubbery polymer is 5 to 20% by weight, (2) Particle size of acrylic ester rubbery polymer is 500 to 2000 mm, (3) Acrylic ester rubbery heavy The relationship between the particle size d of the coalescence and the amount w of crosslinking agent used in the acrylate rubber polymer satisfies the following formula:
0.002d ≦ w ≦ 0.005d d: Å w:% by weight
(4) The graft ratio of the acrylic graft copolymer (A) is 30 to 200%, and (5) the return viscosity of methyl ethyl ketone-soluble component is 0.2 to 0.8 dl / g.
It is the acrylic film formed by shape | molding the resin composition which is.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The resin composition (C) used in the present invention comprises an acrylic graft copolymer (A) containing an acrylic ester rubbery polymer and a methacrylic polymer (B) containing 80% by weight or more of methyl methacrylate. It can be obtained by polymerizing acrylic graft copolymer (A) and methacrylic polymer (B) and mixing them. After producing the copolymer (A), the methacrylic polymer (B) can be produced continuously. As a mixing method, it is possible to mix in the form of latex or powder, beads, pellets and the like. The acrylic graft copolymer (A) used in the present invention is obtained by polymerizing a (meth) acrylic acid ester monomer in the presence of a crosslinked rubber-like polymer containing an acrylic acid ester as a main component. The acrylic ester rubbery polymer is preferably a monomer comprising 60 to 99% by weight of an acrylic ester, 0 to 30% by weight of another copolymerizable vinyl monomer and a specific amount of a copolymerizable crosslinking agent. The mixture is polymerized. All the monomers may be mixed and used, or may be used in two or more stages by changing the monomer composition. As an acrylic ester used here, the thing of C1-C12 of an alkyl group can be used from the point of polymerizability and cost. Specific examples thereof include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, and the like. Also good.
[0006]
As other vinyl monomers that can be copolymerized, methacrylic acid esters are particularly preferred from the viewpoint of weather resistance and transparency, and specific examples thereof include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid. Examples include butyl. Specific examples of aromatic vinyls include styrene and methylstyrene, and examples of vinyl cyanides include acrylonitrile and methacrylonitrile. The amount of the copolymerizable cross-linking agent greatly affects the stress whitening, elongation at break or transparency as well as the average particle size of the acrylate polymer. That is, it is important that the average particle diameter (dÅ) and the amount of the crosslinking agent (w% by weight) of the acrylic ester elastic body satisfy the following formula.
0.002d ≦ w ≦ 0.005d.
[0007]
The average particle size of the rubbery polymer is 500 to 2000 mm. Preferably it is 500 to 1600, more preferably 500 to 1200, most preferably 600 to 1000. If it is 500 mm or less, the elongation at break and impact resistance are undesirably lowered, and if it is 2000 mm or more, stress whitening tends to occur or the transparency is undesirably decreased.
[0008]
The amount of the cross-linking agent is preferably within the range shown in the above formula. Outside this range, stress whitening occurs, elongation at break decreases, transparency decreases, and film formability deteriorates, which is not preferable. . The crosslinking agents used for this purpose may be those usually used. For example, allyl methacrylate, allyl acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl malate, divinyl adipate, divinylbenzene, ethylene glycol Methacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate , tetramethylolmethane tetramethacrylate , dipropylene glycol dimethacrylate, and acrylates thereof can be used. Two or more of these crosslinking agents may be used.
[0009]
The acrylic graft copolymer (A) is obtained by polymerizing a monomer mainly composed of a methacrylic acid ester in the presence of the rubber-like polymer. Preferably, it is obtained by polymerizing 95 to 25 parts by weight of methacrylic acid ester in at least one stage in the presence of 5 to 75 parts by weight of the acrylic ester rubbery polymer. At this time, a component which becomes an ungrafted polymer without grafting to the acrylic ester rubber elastic body is generated. This component constitutes part or all of the methacrylic polymer (B). The graft copolymer becomes insoluble in methyl ethyl ketone. The graft ratio with respect to the acrylic ester rubber elastic body is 30 to 200%, preferably 80 to 200%. When the graft ratio is 30% or less, the transparency is lowered or the elongation is lowered, which is not preferable, and when it is 200% or more, the melt viscosity at the time of film formation becomes high, and the film moldability is deteriorated. Monomers used for the graft reaction include methacrylic acid esters, acrylic acid esters, and the like, and specific examples include those used for the acrylic acid ester rubber elastic body. The proportion of methacrylic acid ester used is preferably 50% by weight or more. If it is 50% by weight or less, the hardness and rigidity of the obtained film are undesirably lowered. The methacrylic polymer (B) used in the present invention contains 80% by weight or more of methyl methacrylate as a polymerization component. If the methyl methacrylate is 80% by weight or less, the hardness and rigidity of the resulting film are not preferred.
[0010]
5-20 weight% is preferable and, as for content of the acrylic rubber elastic body of the resin composition (C) of this invention, 10-20 weight% is more preferable. If it is 5% by weight or less, the elongation of the resulting film is lowered or stress whitening tends to occur, which is not preferable. If it is 20% by weight or more, the hardness and rigidity of the resulting film are undesirably lowered. The reduced viscosity of the methyl ethyl ketone soluble component of the resin composition (C) of the present invention is 0.2 to 0.8 dl / g. If it is 0.2 dl / g or less, the elongation of the resulting film is lowered or the solvent resistance is unfavorable, and if it is 0.8 dl / g or more, the film moldability is undesirably lowered. The method for producing the acrylic graft copolymer (A) and the methacrylic polymer (B) of the resin composition (C) of the present invention is not particularly limited, and emulsion polymerization, suspension polymerization, bulk weight Legal etc. are applicable.
[0011]
In the emulsion polymerization method, a normal polymerization initiator is used. Specific examples include inorganic peroxides such as potassium persulfate and sodium persulfate, organic peroxides such as cumene hydroperoxide and benzoyl peroxide, and oil-soluble initiators such as azobisisobutyronitrile. used. These may be used alone or in combination of two or more. These initiators may be used as usual redox type polymerization initiators in combination with reducing agents such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid , ferrous sulfate and the like. There is no restriction | limiting in particular also in the surfactant used for the said emulsion polymerization, If it is a surfactant for normal emulsion polymerization, it can be used. Examples include anionic surfactants such as sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sodium laurate, and nonionic surfactants such as reaction products of alkylphenols with ethylene oxide. It is. These surfactants may be used alone or in combination of two or more. From the polymer latex obtained by such a copolymer, the resin composition is separated and recovered by ordinary coagulation and washing, or by treatment such as spraying or freezing.
[0012]
The acrylic ester resin composition of the present invention is particularly effective as a film. For example, it can be satisfactorily processed by an inflation method, a T-die extrusion method, a calendar method, or a solvent casting method, which is a normal melt extrusion method. Is done. About 30-500 micrometers is suitable for the thickness of a film, and 50-300 micrometers is more preferable.
[0013]
If necessary, the resin composition (C) can be melted at the same temperature as the glass transition temperature, and both surfaces of the film can be melted simultaneously with a roll or a metal belt to obtain a film with better surface properties.
[0014]
The resin composition (C) of the present invention includes inorganic or organic pigments for coloring, dyes, antioxidants for further improving stability to heat and light, heat stabilizers, ultraviolet absorbers, ultraviolet rays You may add a stabilizer etc. individually or in combination of 2 or more types.
[0015]
【Example】
The following examples illustrate the invention. In the examples and reference examples, “parts” represents parts by weight, and “%” represents% by weight. Abbreviations are as follows.
[0016]
OSA: Dioctyl sodium sulfosuccinate BA: Butyl acrylate MMA: Methyl methacrylate CHP: Cumene hydroperoxide tDM: Tertiary decyl mercaptan EA: Ethyl acrylate.
[0017]
The characteristics and evaluation were in accordance with the following methods and conditions.
[0018]
The average particle size film of the acrylic ester rubber elastic body was dyed with ruthenium and observed with a transmission electron microscope, and the particle size of 500 particles was measured.
[0019]
Graft rate (G)
The powder produced in the reference example was dissolved in methyl ethyl ketone and separated into an insoluble content and a soluble content, and the insoluble content was determined as a graft content by the following formula.
[0020]
G = (weight of insoluble matter−weight of rubber elastic body / weight of rubber elastic body) × 100.
[0021]
The reduced viscosity film was dissolved in methyl ethyl ketone, and the soluble content was measured with 0.3% N, N-dimethylformamide at 30 ° C. Unit: dl / g.
[0022]
The tensile strength and elongation film at break were punched into a JIS type dumbbell and measured at 23 ° C. with an autograph at a tensile speed of 50 mm / min.
Unit: MP is tensile strength and% is elongation at break.
[0023]
The cloud value was measured according to JISK6714 using a transparent film. unit:%.
[0024]
It measured according to JISK5400 using the pencil hardness film.
[0025]
Film formability Film formation was performed for 3 hours, the situation was observed, and the following evaluation was performed.
○: The film thickness is uniform and can be molded without breaking. X: The film thickness is uneven or the film is broken.
[0026]
The surface of the film having a surface area of 1 m ² was observed and evaluated as follows.
○: Fish eye, dilan, and burn are hardly recognized. Δ: Fish eye, dilan, and burn are recognized. ×: Fish eye, dilan, and burn are remarkable.
[0027]
The film was bent 180 degrees at a stress whitening temperature of 23 ° C., and the whitening state was observed and evaluated as follows.
○: Whitening is not recognized Δ: Whitening is slightly observed ×: Whitening is remarkable.
[0028]
(Reference Example 1)
The following substances were charged into an 8 L polymerization machine equipped with a stirrer.
[0029]
Water 200 parts OSA 0.2 parts Ethylenediaminetetraacetic acid-2-sodium 0.001 parts Ferrous sulfate 0.00025 parts Sodium formaldehyde sulfoxylate 0.15 parts After deoxidization, the internal temperature is brought to 60 ° C The mixture (a) shown in Table 1 was continuously added dropwise at a rate of 10 parts / hour, and then post-polymerization was performed for 30 minutes to obtain an acrylic ester elastic body. The polymerization conversion rate was 99.5%. Thereafter, 0.2 part of sodium octylsulfosuccinate was charged, and then the mixture (b) shown in Table 1 was continuously added dropwise at a rate of 12 parts / hour. A graft copolymer (A) and a methacrylic polymer (B) were obtained. The polymerization conversion rate was 99.0%, the graft rate was 135%, and the reduced viscosity of the methyl ethyl ketone-soluble component was 0.35 dl / g. The obtained latex was salted out and coagulated with calcium acetate, washed with water and dried to obtain a resin powder. The reduced viscosity and graft ratio were measured and shown in Table 1.
[0030]
(Reference Examples 2-9)
Reference Examples 2, 3, 4, 5, 6, 7, 8, and 9 were also prepared in the same manner as Reference Example 1 with the formulation shown in Table 1. The reduced viscosity and graft ratio were measured and shown in Table 1.
[0031]
[Table 1]

(Reference Example 10)
Similarly, a copolymer was produced using monomers of MMA 92% and BA 8% by emulsion polymerization. The resulting methacrylic acid ester copolymer had a reduced viscosity of 0.36 dl / g.
[0032]
(Reference Example 11)
A MMA-EA copolymer (Sumitex EX manufactured by Sumitomo Chemical Co., Ltd .; a polymer comprising about 95% MMA and about 5% EA, reduced viscosity 0.30 dl / g) was used which was produced by suspension polymerization.
[0033]
(Examples 1 to 7 and Comparative Examples 1 to 5) 100 parts of the resin composition shown in Table 2 using the obtained polymers, 1.5 parts of Tinuvin 1577 (manufactured by Ciba Special Chemical Co., Ltd.) as an ultraviolet absorber. And 0.3 part of Sumilizer GM (manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant were mixed, and extruded pellets were obtained at 220 ° C. with a vented extruder. The obtained pellets were molded with a T-die extruder at a die temperature of 240 ° C. to obtain a film having a thickness of 100 μm. Various physical properties were evaluated using this film. The results are shown in Table 2.
[0034]
[Table 2]

[0035]
【The invention's effect】
It can be seen that the film of the present invention is excellent in balance between tensile strength, elongation at break, stress whitening, transparency, surface hardness and surface properties.

Claims (3)

(A) A resin composition comprising an acrylic graft copolymer containing an acrylic ester rubbery polymer and (B) a methacrylic polymer containing 80% by weight or more of methyl methacrylate,
(1) The content of the acrylic ester rubbery polymer is 5 to 20% by weight,
(2) The average particle diameter of the acrylic ester rubbery polymer is 500 to 2000 mm,
(3) The relationship between the average particle diameter d (Å) of the acrylic ester rubber-like polymer and the amount w (% by weight) of the crosslinking agent used in the acrylic ester rubber-like polymer satisfies the following formula:
0.002d ≦ w ≦ 0.005d d: Å w:% by weight
(4) A resin composition in which the graft ratio of the acrylic graft copolymer (A) is 30 to 200% and (5) the reduced viscosity of the methyl ethyl ketone soluble part of the resin composition is 0.2 to 0.8 dl / g. A film formed by molding a product. A laminate in which the film according to claim 1 is laminated. An acrylic laminated product, wherein the laminated product according to claim 2 is produced by injection molding.