JP2000309638A - Resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin molded product having a metallic appearance without carrying out coating and excellent even in physical properties. SOLUTION: This resin molded product is obtained by including 0.2-1.5 wt.% of a brightening agent having <=60 μm average particle diameter and 0.0005-0.02 wt.% of a black colorant comprising carbon black in a substrate resin. The lightness of a resin part without containing the brightening agent is matched with the lightness of a dark part of a brightening agent-containing coated surface by coating to thereby afford a metallic appearance as if a large amount of the brightening agent were contained even when the content of the brightening agent is low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallic resin molded article containing a glittering material such as aluminum particles.
More specifically, the present invention relates to a resin molded product having a metallic appearance with a high metallic feeling and excellent physical properties such as impact resistance.

[0002]

2. Description of the Related Art As a coating color for automobiles, a metallic coating containing a luster material such as aluminum particles and mica particles is known. In recent years, designs in which the exterior color of a vehicle has a metallic tone have become mainstream in recent years. Further, in order to make a resin molded product such as a bumper cover or a side molding have the same metallic color tone as the vehicle body color, a metallic paint is applied to the surface of the molded resin molded product.

In order to produce these resin molded products at lower cost, it is desirable to develop a metallic color tone without painting the resin molded product, and studies have been made. For example, JP-B-6-99592 and JP-A-9-99592
Japanese Patent No. 164543 describes production of a resin molded product having a metallic appearance from a thermoplastic resin containing aluminum particles.

[0004]

By the way, in a resin molded article made of a thermoplastic resin containing a brilliant material, a large amount of the brilliant material is contained in order to obtain the same metallic feeling as when a metallic paint is applied. Need to be done. However, when the glitter material is contained in such a large amount, there is a problem that physical properties such as impact resistance of the resin molded product are deteriorated.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a resin molded article having a metallic appearance without coating and having excellent physical properties.

[0006]

Means for Solving the Problems The resin molded product of the present invention which solves the above-mentioned problems is characterized by a base made of a thermoplastic resin, a black colorant contained in the base, and a base made of a thermoplastic resin. And a glittering material having an average particle diameter of 60 μm or less in the substrate.
% By weight, and 0.0005 to 0.02% by weight of a black colorant made of carbon black.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The coating surface of a metallic paint does not have a continuous glossy portion, but rather has a slight inclination due to the irregular inclination of the glitter material mixed in the metallic paint and the unevenness of the surface to be coated. It is in a continuous state of light and dark. on the other hand,
The color tone of the resin molded article containing the glittering material is perceived when the color tone of the base resin and the reflected light (metallic color) of the glittering material are mixed and visually recognized.

In the resin molded product of the present invention, the brightness of the resin portion is increased by adding 0.0005 to 0.02% by weight of a black colorant made of carbon black to the resin portion containing the glitter material. By matching the brightness of the dark part of the coating film surface, the minute brightness on the metallic coating surface is reproduced in the resin molded product. Therefore, even if the content of the glittering material is small, a metallic appearance as if it contains many glittering materials can be obtained.

As the substrate, various thermoplastic resins such as polypropylene, polyethylene, ABS, acrylic resin, polyamide and polyester can be used. The glittering material is contained in the substrate in an amount of 0.2 to 1.5% by weight. In the resin molded article of the present invention, as described above, since the resin portion containing the glittering material is perceived by an illusion as a metallic color containing a large amount of glittering material, the content of the glittering material can be reduced in this manner. When the content of the glittering material is less than 0.2% by weight, it is difficult to perceive the glittering feeling, and the resin molded product cannot have a metallic appearance. On the other hand, when the content of the glittering material is more than 1.5% by weight, physical properties such as impact resistance of the resin molded product are reduced.

[0010] The glittering material has a particle diameter of 60 µm or less. In the glittering material whose particle size exceeds 60 μm,
If the content is 0.2 to 1.5% by weight, it is difficult to give the resin molded article a metallic appearance, so it is necessary to increase the content to about 2.0% by weight. However, in a resin molded article containing such a large amount of glittering material, the physical properties are reduced as described above. The lower limit of the particle size of the glittering material is not particularly limited, but if it is less than 20 μm, there is a problem that the weld line at the time of molding is conspicuous.
It is particularly preferred that the thickness be at least μm.

As the glitter material, known glitter materials such as aluminum particles, mica particles and pearl mica particles can be used. In some cases, the internal bubbles contained in the base material can be used as a brilliant material. As the glittering material, those having a particle shape with an aspect ratio of 5 to 50 are desirable. By using such a scaly brilliant material, the brilliant material particles are easily oriented parallel to the surface of the resin molded product at the time of injection molding, and a high metallic feeling is exhibited with a smaller amount.

The resin molded article of the present invention may be used in combination with other coloring pigments or dyes in a small amount. For example, when pearl mica is used as a brilliant material, various interference colors are generated due to light interference. Therefore, the content of the brilliant material is further reduced by using a pigment or a dye having a color tone similar to the interference color. It is possible. Further, a filler such as talc or barium sulfate may be contained within a range that does not affect physical properties and appearance.

In the resin molded article of the present invention, it is possible to obtain a metallic-painted design having a high appearance quality even if the surface of the substrate is smooth, but in order to obtain a higher design, the molded article is required. Preferably, a satin-like grain is formed on the surface. At this time, the depth of the grain is the particle diameter of the glittering material ± 25.
It is desirable to be in the range of μm. By making the depth of the grain approximately equal to the grain size of the glitter, it becomes difficult to visually separate the shadow produced by the grain of the grain from the glitter, and a high metallic appearance with a small amount of glitter Is expressed.

The resin molded article of the present invention can be formed by injection molding, extrusion molding, press molding or the like. In addition, the surface of the obtained resin molded product may be coated with a clear paint or a smoke paint to obtain a resin molded product having higher appearance quality. Furthermore, a transparent, smoked or colored film may be arranged in a molding die, and integrated with the film simultaneously with molding to obtain a resin molded product having a film layer. Even in this case, a resin molded product having higher appearance quality can be obtained.

[0015]

The present invention will be specifically described below with reference to examples, comparative examples and test examples. <Test example> Impact resistant polypropylene for vehicle interior parts ("TSOP
-GP5 "(manufactured by Grand Polymer Co., Ltd.), 0.007% by weight of carbon black as a black colorant, and 0% by weight of aluminum particles having an average particle diameter of 50 μm and an average aspect ratio of 25. % By weight, 1.5% by weight
And 3.0% by weight were mixed at four levels, and test pieces were produced by injection molding.

With respect to the obtained test pieces, various characteristic values were measured. Table 1 and FIG. 1 show the respective results when the measurement result of the test piece containing 0% by weight of aluminum particles was set to 100.

[0017]

[Table 1]

From FIG. 1, it can be seen that the characteristic value reduced by the addition of aluminum particles is remarkable in the IZOT impact value, and in order to maintain the IZOT impact value of 80% or more, the mixing amount of the aluminum particles is 1.5% by weight. In the following, it is apparent that it is particularly necessary to set the content to 1% by weight or less. Example 1 0.007% by weight of carbon black and 0.6% by weight of aluminum particles having an average particle diameter of 30 μm were mixed with polypropylene, and a resin molded product having a smooth surface was produced by injection molding.

EXAMPLE 2 0.0013% by weight of carbon black based on polypropylene and an average particle diameter of 40 μm
Then, 0.6% by weight of aluminum particles of m were mixed, and a resin molded product having a smooth surface was produced by injection molding. (Comparative Example 1) Average particle size of 40 μm with respect to polypropylene
Then, 0.6% by weight of aluminum particles of m were mixed, and a resin molded product having a smooth surface was produced by injection molding.

Comparative Example 2 0.03% by weight of carbon black and 0.6% by weight of aluminum particles having an average particle diameter of 40 μm were mixed with polypropylene, and a resin molded product having a smooth surface was produced by injection molding. (Example 3) 0.0013% by weight of carbon black and 0.6% by weight of aluminum particles having an average particle diameter of 40 µm were mixed with polypropylene, and a resin molded product was formed by injection molding using a mold having a grain pattern. Manufactured. The surface of the obtained resin molded product had a depth a = 35 as shown in FIG.
A grain having a shape of μm is formed.

EXAMPLE 4 0.0013% by weight of carbon black based on polypropylene and an average particle diameter of 40 μm
m of aluminum particles of 0.6% by weight were mixed, and a resin molded product was produced by injection molding using a mold having a grain pattern. On the surface of the obtained resin molded product, a depth a = 65 μm
Is formed.

EXAMPLE 5 0.0013% by weight of carbon black based on polypropylene and an average particle diameter of 40 μm
m of aluminum particles of 0.6% by weight were mixed, and a resin molded product was produced by injection molding using a mold having a grain pattern. On the surface of the obtained resin molded product, a depth a = 10 μm
Is formed.

Example 6 0.0013% by weight of carbon black based on polypropylene and an average particle diameter of 40 μm
m of aluminum particles of 0.6% by weight were mixed, and a resin molded product was produced by injection molding using a mold having a grain pattern. The surface of the obtained resin molded product has a depth a = 115 μm.
An m-shaped grain is formed.

<Tests / Evaluations> The metallic molded articles of the above Examples were visually observed at the window on the north side to evaluate the metallic feeling. Table 2 shows the results. The evaluation was divided into a molded article group having no grain and a molded article group having grain, and a relative evaluation was made in each group.
◎ indicates that the metallic feeling is particularly excellent, and 、
Indicates that the metallic feeling is excellent, Δ indicates that the metallic feeling is slightly inferior, and X indicates that no metallic feeling is obtained.

[0025]

[Table 2]

According to the evaluation of the molded article group having no grain, 0.0005 to 0.02% by weight of carbon black was used.
It can be seen that a good metallic feeling can be obtained by the addition. Also, from the evaluation of the group of molded articles having grain, it can be seen that a higher metallic feeling can be obtained when the grain depth is closer to the particle diameter of the aluminum particles. Although the embodiments of the present invention have been described above, the embodiments of the present invention include embodiments of the following various technical matters in addition to the technical matters described in the claims. Is added. (1) A base material made of a thermoplastic resin, a black colorant contained in the base material, and a particulate brilliant material contained in the base material, and the brilliant material-containing coating surface is formed by coating. A resin molding used adjacently, wherein the base material has an average particle diameter of 60
a glitter material having a particle size of 0.2 μm or less is contained in an amount of 0.2 to 1.5% by weight, and
A resin molded product which is added at 0.02% by weight and the brightness of the resin portion of the base material is matched with the brightness of the dark portion of the surface of the coating film containing the glittering material by the coating.

[0027]

According to the resin molded product of the present invention,
The addition of a small amount of the brilliant material provides high physical properties and a high metallic feeling.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the content of aluminum particles and various characteristic values.

FIG. 2 is an explanatory diagram showing a depth of a grain;

Claims (2)

[Claims] 1. A resin molded article comprising a base material made of a thermoplastic resin, a black colorant contained in the base material, and a particulate glittering material contained in the base material, The base material contains a glittering material having an average particle diameter of 60 μm or less.
A resin molded product containing 2 to 1.5% by weight, and 0.0005 to 0.02% by weight of a black colorant made of carbon black. 2. The resin according to claim 1, wherein a satin-like grain is formed on a surface of the base material, and a depth of the grain is in a range of a particle diameter of the glittering material ± 25 μm. Molding.