JPH08127107A - High gloss resin molded object - Google Patents

Abstract

PURPOSE: To provide a high gloss resin molded object capable of obtaining a high gloss feeling, a metallic feeling and scratch resistance almost same to those of a painted product and capable of omitting a painting process. CONSTITUTION: A resin molded object consists of a core layer 2 and the skin layer 3 applied to the periphery of the core layer 2. The core layer 2 is composed of a polypropylene type composite material while the skin layer 3 is composed of a mixture of a polypropylene resin and a coloring agent. The polypropylene resin of the skin layer 3 contains 6wt.% or less of ethylene or contains no ethylene and has Rockwell hardness of 85 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product used for automobile exterior parts and the like, and particularly to a high-gloss resin molded product having a high gloss feeling.

[0002]

2. Description of the Related Art In order to obtain a beautiful appearance, side moldings, bumper corners and the like used for exterior parts of automobiles are required to have high glossiness, that is, high glossiness. on the other hand,
Exterior products such as side moldings are easy to install in automobiles,
From the viewpoint of flexibility, strength, etc., a resin molded body is usually used.

As the above-mentioned resin molded body, polypropylene resin containing glass fiber (hereinafter referred to as PPG), polyolefin type thermoplastic elastomer, and the like are used.
There are olefin-based composite materials. Then, in order to exhibit the above-mentioned high glossiness, the surface of the resin molded body is coated with a metallic or solid tone.

[0004]

However, the above-mentioned conventional resin molding having high gloss has the following problems. That is, since the coating process is required, the manufacturing process cannot be rationalized, resulting in high cost. Further, when the resin molded body is simply colored by adding a pigment in order to omit the coating process, a high quality that can be applied to exterior products cannot be obtained.

Conventionally, as a method for improving the high gloss and metallic feeling of a colored resin, a method of specifying a pigment component or a pigment dispersant (Japanese Patent Laid-Open Nos. 1-308441 and 25584).
2,4-7363,2-214747,5-27809
9, JP-A-61-138652), by improving the method for producing a colored resin (JP-A-51-49264, JP-A-1).
No. 301748), a resin component improved (Japanese Patent Laid-Open No. 60-152543, 62-84142) and the like have been proposed, but none of them has the same high glossy feeling and metallic feeling as the coated product.

That is, when the coating step is omitted, it is not possible to develop a high glossy feeling, a metallic feeling, etc., which are comparable to those of the coated product, and the scratch resistance is inferior to that of the coated product.
The present invention has been made in view of the above-mentioned conventional problems, and it is possible to obtain the same high gloss feeling, metallic feeling, and scratch resistance as those of coated products, and to omit the coating process. , It is intended to provide a high-gloss resin molded body.

[0007]

The present invention provides a resin molded product comprising a core layer and a skin layer coated around the core layer,
The core layer is made of polypropylene-based composite material, while the skin layer is made of a mixture of polypropylene resin and a colorant, and the polypropylene resin in the skin layer contains 6% by weight or less of ethylene. It is a high-gloss resin molded product characterized by being a polypropylene resin having a Rockwell hardness of 85 or more, which does not contain the above.

The polypropylene resin in the skin layer is a polypropylene resin which does not contain ethylene or contains 6% by weight or less of ethylene and has a Rockwell hardness of 85 or more. As a result, it is possible to surely obtain a high glossy feeling, metallic feeling, and scratch resistance equivalent to those of a coated product. Further, when the content of ethylene exceeds 6% by weight, or when the Rockwell hardness of the polypropylene resin is less than 85, the same high glossy feeling, metallic feeling, and scratch resistance as those of coated products are obtained. I can't.

Examples of the polypropylene resin for the skin layer include crystalline homopolypropylene, crystalline propylene-ethylene random copolymer, crystalline propylene-ethylene block copolymer, and mixtures thereof.

Of these, a highly crystalline polypropylene resin having a high isotactic index (Rockwell hardness of 95 or more) is particularly preferable. Further, among these, a highly crystalline homopolypropylene resin (Rockwell hardness of 105 or more) is most preferable. As a result, it is possible to obtain more excellent high gloss feeling, metallic feeling, and scratch resistance. Here, the isotactic index is ¹³ C-
It is the isotactic fraction in the triad unit of the methyl group by NMR method.

The polypropylene-based composite material in the core layer preferably contains a polypropylene resin containing either one or both of a rubber component and an inorganic filler. This makes it possible to obtain a core layer having appropriate flexibility and rigidity. The polypropylene resin for the core layer includes homopolypropylene, block polypropylene, random polypropylene, and a mixture thereof.

The rubber component is amorphous ethylene-
It is preferably one or more selected from the group of α-olefin copolymers and styrene-based thermoplastic elastomers. This makes it possible to obtain appropriate flexibility and improve strength characteristics such as low temperature impact resistance.

The above-mentioned amorphous ethylene-α-olefin copolymer includes propylene as an α-olefin component,
Butene-1, Penten-1, Hexane-1, Octene-
1,4-methylpentene-1, heptene-1 and the like.
Further, as the styrene-based thermoplastic elastomer,
SEBS, SEPS, SEP, SEEPS, SBS, S
There are IS etc.

The inorganic filler is glass fiber,
It is preferably at least one selected from the group consisting of talc, mica, calcium carbonate, wollastonite, clay, barium sulfate, potassium titanate whiskers, magnesium sulfate whiskers, calcium carbonate whiskers, and silica. This can also improve strength characteristics such as low temperature impact resistance.

As the colorant, either an inorganic pigment or an organic pigment can be applied. The inorganic pigments include titanium white, zinc oxide, zinc sulfide, red iron oxide, chrome yellow, barium yellow, ultramarine blue, cobalt blue, cobalt green,
There are carbon blocks and luster materials such as aluminum powder, aluminum flakes, aluminum foil, pearl mica, zinc powder, and bronze powder.

Examples of the above organic pigments include Watching Red, Permanent Red, Para Red, Toluidine Maroon, Benzidine Yellow, Phthalocyanine Blue, Phthalocyanine Green, Fast Sky Blue, Brilliant Carmine 6B and the like.

[0017]

FUNCTION AND EFFECT The high-gloss resin molding of the present invention comprises a core layer and a skin layer covering the core layer. The core layer is made of polypropylene composite material. Therefore, the strength of the product such as rigidity and flexibility can be adjusted by the polypropylene-based composite material of the core layer. Therefore, the skin layer can be selected to have the best appearance and scratch resistance without taking special strength characteristics into consideration.

The skin layer is made of a mixture of the specific polypropylene resin and the colorant. for that reason,
In the skin layer, the phenomenon of desorption of the pigment from the surface to the inner side occurs, and the surface layer is transparent and does not contain the coloring agent.
A layer like a clear layer is formed. Therefore,
In the high-gloss resin molded product of the present invention, a glossy feeling with a depth comparable to that of a coated product can be obtained. In particular, when the above-mentioned glitter material is used as a pigment, the glitter material is inside,
Since a layer such as the above clear layer is formed on the surface,
The same metallic feeling as that of metallic coated products can be obtained.

Further, since the skin layer is made of the above specific polypropylene resin, it has a high hardness and is hard to be scratched on the surface. Therefore, the high-gloss resin molded product of the present invention does not need to be separately coated in order to obtain the same high-gloss feeling, metallic feeling, and scratch resistance as those of the coated product.

As described above, according to the present invention, it is possible to obtain the same high glossy feeling, metallic feeling, and scratch resistance as those of the coated product, and to omit the coating process.
A high-gloss resin molding can be provided.

[0021]

【Example】

Examples 1 to 7 High gloss resin molded products according to the examples of the present invention will be described together with comparative examples. In this example, using a test piece,
The glossiness, appearance, scratch resistance, and low temperature impact resistance were evaluated. As the test piece, a flat plate molded by a sandwich type injection molding machine into a size of width 60 mm × length 120 mm × thickness 3 mm was used. In addition, a part of the comparative example is not a sandwich molded product having a two-layer structure including a core layer and a skin layer, but a single-layer molded product.

The composition and properties of the materials used in this example are shown in Table 1. Examples 1 to 7 and Comparative Example 1 shown in Table 5
Sample No. 9 was selected from the materials with the composition numbers shown in Table 1,
The materials for the core layer and the skin layer were selected and used (only one type of single-layer sample piece was selected). And the pigment mentioned later was mixed in the skin layer.

As shown in Table 1, five kinds of crystalline polypropylene resins (hereinafter abbreviated as PP) were prepared as materials. Further, as shown in Table 2, two types of PP containing amorphous ethylene / propylene rubber and talc were prepared as a rubber-modified PP group. Incidentally, PPG
Is a mixture of PP and glass fibers. Further, rubber-modified PP and PP contained in PPG (PP-6 to P
The ethylene content and MFR (melt flow index) of P-8) are shown in Table 3.

Further, as the colorant, two kinds of pigments having the components and blending ratios shown in Table 4 were used. The pigment M has a dark blue metallic color, and the pigment S has a dark blue color. Next, Table 5 shows each material of the skin layer and the core layer in Examples 1 to 7 and Comparative Examples 1 to 9 and the test results described later. In Table 5, each material is the sample No. (Table 1, Table 3) -The order of the pigment symbol (Table 4) is shown.
For example, in the skin layer of Example 1, since the sample of PP-1 is used and the pigment M is used, it is referred to as PP-1-M.

With respect to the above PP, the Rockwell hardness and MFR (melt flow index) were measured as its characteristics, and the results are shown in Table 1. The Rockwell hardness was measured by R scale according to JIS-K7207. In addition, MFR conforms to JIS-K6758,
It was carried out with a load of 2160 g at a temperature of 230 ° C.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

Each evaluation result will be described below with reference to Table 5. First, the gloss evaluation result will be described. The gloss is 6 according to JIS-Z8741 by a gloss measuring instrument.
The 0 ° specular gloss value was measured and evaluated. When the above-mentioned glossiness exceeds 70%, a glossiness comparable to that of a coated product can be sufficiently obtained, so that value was set as a target value.

As a result of the test, as shown in Table 5, Examples 1 to 3 in which 1 to 3 of PP were used for the skin layer or the single layer
7 and Comparative Examples 5 and 6 are 7 even if any pigment is used.
It showed a high glossiness of 0% or more. Also, its glossiness is
The higher the crystallinity, that is, the higher the Rockwell hardness, the higher the value.

Next, the result of evaluation of appearance will be described. The appearance was evaluated by visually observing the molded test piece. The evaluation standard is that the appearance quality of the test piece is equivalent to 1 grade and the appearance quality of the test piece is 2 compared to the appearance quality of the coated product.
The grades markedly inferior were designated as grade 3, and grades 1 and 2 were set as target values.

As a result, as shown in Table 5, as in the gloss test results, those in which 1 to 3 of high crystalline PP were used for the skin layer or the single layer showed good appearance of the second grade or higher. It was In particular, the products using the high crystalline PPs 1 and 2 showed the excellent appearance almost equivalent to the coated product.

Next, the results of the scratch resistance test will be described. The scratch resistance was measured using a surface property tester manufactured by Shinto Chemical Co., Ltd. according to the test method shown in JIS-K5401. Specifically, an iron pin with a diameter of 2 mmφ was set in the direction of 45 ° to the test piece, the surface of the test piece was scratched at a constant speed of 150 mm / sec while applying a load of 100 g, and the scratch was based on the following criteria. evaluated.

That is, in the test piece, the case where no scar was observed at all was grade 1, the case where scar was scarcely observed was grade 2, the case where scar was slightly recognized was grade 3, and the case where scar was noticeable was 4 The target values were the first and second grades.

As a result of the test, as shown in Table 5, those in which 1 to 3 of high crystalline PP and PPG were used for the skin layer or the single layer showed good scratch resistance of the second grade or higher. Particularly, those using the high crystalline PPs 1 and 2 showed no scratches at all and showed excellent scratch resistance.

Next, regarding the results of the low temperature impact resistance test,
explain. In the low temperature impact resistance test, the test piece is left for 3 hours in an atmosphere of −30 ° C., and then a steel ball with a diameter of 50 mmφ and a weight of 1 kg is dropped, and the test piece breaks (cracks and cracks enter). It was measured and evaluated.

As a result of the test, in the test piece composed of a single layer, as shown in Comparative Examples 1 to 7 in Table 5, the rubber-modified PP was used.
A large difference was observed between the high crystalline PP and the high crystalline PP. That is, the rubber-modified PP exhibited excellent low-temperature impact resistance that was not destroyed even when the steel balls were dropped from a height of 150 cm or more. On the other hand, PP alone showed impact resistance considerably inferior to that of rubber-modified PP. In addition, PPG exhibited a performance intermediate between that of rubber-modified PP and PP alone.

For the two-layer structure test piece, Table 5
As shown in Examples 1 to 7 and Comparative Examples 8 and 9, the performance of the material used for the core layer (performance of Comparative Examples 1 to 7) appeared as it was. That is, the one using rubber-modified PP for the core layer showed better low temperature impact resistance than the one using PPG.

Summarizing the above-mentioned four evaluation results, the appearance quality represented by glossiness and appearance is preferably that using PP 1 to 3 for the skin layer or the single layer. On the other hand, those using rubber-modified PP and PPG cannot obtain the same excellent appearance quality as the coated product. In addition, although the appearance quality of the single layer product using PP is good,
Its low temperature impact resistance is inferior, so it is not suitable for use as an automobile exterior part.

As described above, according to the present invention, it is possible to obtain the same high gloss feeling, metallic feeling, and scratch resistance as those of the coated product, and to omit the coating process.

[0042]

[Table 5]

Example 8 As shown in FIG. 1, the high-gloss resin molding of this example is a side molding material for an automobile, which comprises a core layer 2 and a skin layer 3 coated around the core layer 2. . The core layer 2 is made of polypropylene composite material, while the skin layer 3 is made of a mixture of polypropylene resin and colorant.

As in Example 1, the polypropylene resin in the skin layer 3 does not contain ethylene,
A polypropylene resin having a Rockwell hardness of 113 was used. As the colorant, the pigment M (Table 4) used in Examples 1 to 5 was used. Further, the polypropylene-based composite material in the core layer 2 is the same as in Example 1,
Highly crystalline polypropylene resin contains 60% by weight of amorphous ethylene / propylene rubber and 10% by weight of talc.

The side molding 10 of this example was molded by a sandwich type injection molding machine using the above materials. In the side molding 10 of this example, similar to Example 1, the same high glossiness, metallic feeling, and scratch resistance as those of the coated product were obtained. Further, as in the case of Example 1, since it is also excellent in low temperature impact resistance, it can sufficiently exhibit the function as a side molding.

In addition to the side moldings, the present invention provides exterior products such as wheel covers, side garnishes, rocker panels, bumpers, bumper corners, spoilers, center pillars, interior products such as meter clusters, center clusters, garnishes, etc. It can be applied to various transportation equipment that requires high gloss and various industrial equipment such as electrical products. In addition to the sandwich injection molding method, the above-mentioned molded body can be manufactured by two-layer extrusion molding, two-layer blow molding, or the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a side molding according to an eighth embodiment.

[Explanation of symbols]

 10. . . Side mall, 2. . . Core layer, 3. . . Skin layer,

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 7/04 CES Z // C08L 23/10 KCS LCB

Claims (4)

[Claims] 1. A resin molding comprising a core layer and a skin layer coated around the core layer, wherein the core layer is made of polypropylene-based composite material, while the skin layer is made of polypropylene resin and colored. The polypropylene resin in the skin layer contains 6% by weight or less of ethylene or does not contain ethylene.
A high-gloss resin molded product characterized by being a polypropylene resin having a Rockwell hardness of 85 or more. 2. The high-gloss resin molded product according to claim 1, wherein the polypropylene-based composite material in the core layer contains a polypropylene resin containing one or both of a rubber component and an inorganic filler. . 3. The high-gloss resin molding according to claim 2, wherein the rubber component is one or more selected from the group consisting of an amorphous ethylene-α-olefin copolymer and a styrene-based thermoplastic elastomer. body. 4. The inorganic filler according to claim 2, wherein the inorganic filler is glass fiber, talc, mica, calcium carbonate, wollastonite, clay, barium sulfate, potassium titanate whiskers, magnesium sulfate whiskers, calcium carbonate whiskers, A high-gloss resin molded product, which is one or more selected from the group of silica.