JP5482480B2 - Metallic color molding resin composition - Google Patents

Description

  The present invention relates to a metallic color tone molding resin composition containing a glittering material.

  For example, colored coatings are widely used to improve aesthetics in interior and exterior products in the automobile industry. In addition, as a kind of colored coating, there are many users who prefer metallic color coating including a bright material such as aluminum powder or pearl pigment. However, many volatile organic compounds (VOC) are contained in the paint used for such colored coating, and problems such as an adverse effect on the environment and an increase in the number of work steps have been pointed out. Therefore, in recent years, it has also been proposed to directly use a molded body of a colored resin composition kneaded in advance with a colorant or a bright material as an interior / exterior part (for example, Patent Document 1).

JP 2010-106201 A

  However, according to the study by the present inventors, several problems have been found in the expression of metallic color tone by resin coloring. One of them is that the gloss or brightness is significantly reduced after the exposure test (JIS K7350-2), compared to the case of resin coloring by blending ordinary coloring pigments such as white, red and black. Is not obtained. This tendency is conspicuously observed in molded resin materials containing butadiene rubber in order to improve the impact resistance required for interior and exterior products in addition to acrylic resins having excellent weather resistance, which is also a main vehicle such as paint. And according to the study of the present inventors, the decrease in the gloss rate due to the exposure test of the above-described metallic color-colored resin molded product is such that incident light is reflected by the glitter material existing under the surface skin layer of the molded product, and again Since it passes through the skin layer, the deterioration of the skin layer containing butadiene rubber is promoted, and therefore, it is understood that the gloss is significantly lowered as compared with the colored resin molded body to which no glittering material is added.

  Accordingly, a main object of the present invention is to provide a metallic color molding resin composition that effectively suppresses a decrease in gloss caused by an exposure test even in a butadiene rubber-containing acrylic resin containing a glittering material.

  According to the study by the present inventors, it has been found that the addition of a hindered amine compound having an NH-type piperidine ring is extremely effective for achieving the above-mentioned object among a number of weather resistance stabilizers. . The addition of a hindered amine compound having an NR type or NOR type piperidine ring is not effective, and the addition of a hindered phenol compound is not effective by itself, but rather reduces the addition effect of the NH type hindered amine compound. (See Examples and Comparative Examples below). Probably, NH type hindered amine compound has an excellent exposure stability stabilizing effect because its moderate basicity shows good interaction with glittering materials such as aluminum powder and pearl pigment in addition to its original light stabilizer effect. It is understood that it is performing.

The metallic color tone molding resin composition of the present invention is based on the above-mentioned knowledge, and the hindered amine compound containing an NH type piperidine ring structure is used with respect to 100 parts by weight of a butadiene rubber-containing acrylic resin containing aluminum powder as a glittering material. .25 to 1.0 part by weight, and it contains no hindered phenolic compounds including those used as antioxidants, metal deactivators or ultraviolet absorbers .

  Hereinafter, the present invention will be described more specifically with respect to preferred embodiments thereof.

(Acrylic resin containing butadiene rubber)
As a main component (matrix component) of the metallic color tone molding resin composition of the present invention, a butadiene rubber-containing acrylic resin in which transparency, weather resistance and impact resistance are harmonized is used. MBS (methyl methacrylate-butadiene-styrene copolymer) resin is not used, but butadiene- (meth) acrylate copolymer containing no components other than butadiene and acrylic resin components alone or with (meth) acrylate ( A mixture with a (co) polymer is more preferred because it exhibits a better balance of transparency, weather resistance and impact resistance.

(Bright material)
A glittering material is blended with the butadiene rubber-containing acrylic resin to form a metallic tone resin composition. As the glitter material, aluminum powder suitable for expressing a metallic silver color is used. From the viewpoint of effect of imparting glitter, dispersibility, and moldability of the resulting composition, blended at a ratio of 0.05 to 10 parts by weight, particularly 0.1 to 4 parts by weight, with respect to 100 parts by weight of the butadiene rubber-containing acrylic resin. It is preferable to do. For the same reason, the glittering material is preferably a granular material having an average particle diameter of 5 to 120 μm, particularly 5 to 20 μm, as observed under a microscope.

(Light stabilizer)
In accordance with the present invention, a hindered amine compound having an NH type piperidine ring is blended as a light stabilizer in addition to the butadiene rubber-containing acrylic resin and the glittering material. Here, the NH type piperidine ring structure means a ring structure in which the characteristic group = NH of piperidine C ₅ H ₅ NH is maintained as it is. As shown in Examples described later, this NH type hindered amine compound exhibits an excellent post-exposure gloss maintenance effect as compared with an alkyl-substituted NR type or alkoxy-substituted NOR type hindered amine compound. Both a low molecular weight type and a high molecular weight type are used, but the low molecular weight type is more excellent with respect to the light stabilizer effect, while the high molecular weight type is more compatible with the butadiene rubber-containing acrylic resin. It is also preferable to use both in order to balance the light stabilizer effect and compatibility. Examples of commercially available products include TINUVIN770DF (bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine)) as a low molecular weight type, and CHIMASSORB 2020FDL (dibutylamine-) as a high molecular weight type. 1,3,5-triazine-N, N-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine) and N- (2,2,6,6-tetra Methyl-4-piperidyl) butylamine polycondensate) (both manufactured by Ciba Geigy). In order to balance the light stabilizer effect and compatibility, 0.25 to 1.0 parts by weight, preferably 0.25 to 0, of at least one NH-type hindered amine compound is used per 100 parts by weight of the butadiene rubber-containing acrylic resin. Add in the range of 6 parts by weight. However, adding a low molecular weight type hindered amine compound alone in excess of 0.6 parts by weight tends to cause problems such as bleeding and fogging and should be avoided. Even when the low molecular weight type and the high molecular weight type are used in combination, the total amount is preferably suppressed to 0.6 parts by weight.

  It should be noted that the addition of an NR type or NOR type hindered amine compound in addition to the NH type hindered amine compound is not effective in improving the light stabilizer effect, and in particular, the addition of a hindered phenol compound is not possible with the light of the NH type hindered amine compound. It should rather be avoided as it tends to diminish the stabilizer effect.

(Composition)
The metallic color molding resin composition of the present invention is obtained by dry-mixing or melt-mixing the above components, and is used for molding various interior and exterior products by, for example, injection molding at 230 to 270 ° C., extrusion molding, and the like.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

(Examples and comparative examples)
Mitsubishi Rayon Co., Ltd. butadiene rubber-containing acrylic resin “Acrypet VRL40” (Methyl methacrylate-methyl acrylate copolymer and butadiene-alkyl acrylate-alkyl methacrylate copolymer; total light transmittance (JIS K7361): 92%, Izod impact strength (JIS K7110): 9.2 KJ / m ² ) 100 parts by weight of aluminum powder as a bright material (average particle size: 5 μm; “Aluminum paste PA type” manufactured by Toyo Aluminum Co., Ltd.) 1.5 parts by weight, and further, each of the weather resistance stabilizers shown in Table 1 described below were blended in the indicated amounts, respectively, were injection molded at 250 ° C., 79 mm × 87 mm × 3 mm (thickness) The following accelerated light resistance test was carried out using a test piece that was molded into a piece and cut out to 60 × 70 mm.

<Accelerated light resistance test>
Using a “Ci4000 xenon weatherometer” manufactured by ATLAS as a testing machine, the test piece was irradiated from a light source xenon arc lamp separated by 30 cm after 370 hours (exposure amount: exposure amount: 100 MJ / ^{m 2)} and 740 hours (amount of exposure: about 200 MJ / ^{m 2)} on each test piece was taken out, 60 ° specular gloss (incident angle 60 ° before and after exposure, the reflected light at the reflection angle of 60 ° strength ) Was measured according to JIS Z8741-1997, and the gloss residual ratio after exposure was determined by the following formula:
Gloss residual ratio (%) = (Glossiness after exposure / Glossiness before exposure) × 100
Empirically, if the gloss remaining ratio at an exposure amount of 200 MJ / m ² by the accelerated light resistance test is 80% or more, it is determined to be acceptable.

<Compatibility determination>
After molding of the test piece obtained above, the state after standing at 80 ° C. for 24 hours was visually observed, and the compatibility between the stabilizer and the butadiene rubber-containing acrylic resin was determined based on the presence or absence of bleeding and fogging.

The results are summarized in Table 1 below.

According to the above Table 1, according to the present invention, a composition in which 0.25 to 1.0 part by weight of NH type hindered amine compound is blended with 100 parts by weight of butadiene rubber-containing acrylic resin containing aluminum powder has an exposure amount of 200 MJ / m. ^When the accelerated light resistance test of No. ² was conducted, it was found that a glossy residual ratio of 80% or more was obtained, and a practically sufficient metallic tone molding resin composition was obtained.

  As described above, according to the present invention, in order to solve the problems of the coating system using an organic solvent, in the resin coloring composition under development, in particular, the metallic color molding resin composition containing a glittering material, the impact resistance In addition, when a butadiene rubber-containing acrylic resin is used in order to harmonize the weather resistance, a metallic color molding resin composition that effectively suppresses the reduction in gloss that was a problem is provided.

Claims (7)

The aluminum powder 100 parts by weight of butadiene rubber-containing acrylic resin containing a blended with hindered amine compound from 0.25 to 1.0 parts by weight including the NH-type piperidine ring structure becomes as bright materials, antioxidants, metal- A metallic color molding resin composition containing no hindered phenol compound, including those used as an activator or an ultraviolet absorber . The resin composition according to claim 1, wherein the NH type hindered amine compound is a low molecular weight type hindered amine compound. The resin composition according to claim 1, wherein the NH type hindered amine compound is a high molecular weight type compound. The resin composition according to claim 1, wherein the NH type hindered amine compound is a combined system of a high molecular weight type compound and a low molecular weight type compound. The resin composition according to any one of claims 1, 2, and 4, wherein the low molecular weight type hindered amine compound is bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine). High molecular weight hindered amine compounds are dibutylamine-1,3,5-triazine-N, N-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine) and N- 5. The resin composition according to claim 1, which is a polycondensate of (2,2,6,6-tetramethyl-4-piperidyl) butylamine. The resin composition according to any one of claims 1 to 6, wherein 0.25 to 0.6 parts by weight of an NH type hindered amine compound is blended per 100 parts by weight of the butadiene rubber-containing acrylic resin.