JPS6149817A - Resin-molded article - Google Patents

Abstract

PURPOSE:To offer a molded article having an appearance in a galactic tone, by injecting resin obtained by compounding 0.1-20vol% metallic particles whose outside diameter is 10mum-1mm. so that a mean gap D of the metallic particles becomes larger than a weld width H. CONSTITUTION:Metallic particles 4 whose outside diameter is 10mum-1mm. and having metallic luster such as aluminum is injected by compounding 0.1-20 volume part to 100 volume part resin. When the metallic particle diameter is less than 10mum, though the same becomes a metallic tone and a weld line 3 becomes conspicuous, as the particle diameter is large, a molded article having appearance (galactic tone) like the galaxy being inlaid in the night sky for shining can be obtained. The article is suitable for a camera, VTR and container of a cosmetic.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to cameras, VTRs, OA equipment, electric razors,
Related to resin molded products used for cosmetic containers, etc.

[Prior art]

Conventionally, molded products made by mixing and melt-molding thermoplastic resin and metal particles have been known, and these can be roughly classified into three types depending on the purpose. The first is, for example, JP-A-58
As disclosed in Publication No. 37045, metal powder with a particle size of approximately 203 m1 or less (here, metal powder refers to an aggregate of metal particles) is added to ABS resin from 2 to 20 P H.
R (Parts per Hundred of Res)
In, parts by weight, hereinafter the same) are mixed in to obtain a molded product with a uniform metallic appearance, that is, a metallic appearance on the entire surface. However, when injection molding a metallic appearance mold, metal powder containing The flow cross section of the resin is the second
, 3, a layer 2 without metal particles 1 exists at the tip of the flow during the flow process, so that a layer weld line 3 of only resin without metal powder is formed at the junction of the resins. Since the weld line layer does not contain metal powder, it absorbs light and appears black, significantly impairing its appearance. Therefore, conventional resin molded products having a metallic appearance cannot be used for high-grade molded products with complex shapes such as camera exterior covers.

The second method is to add 1 piece of metal particles with a particle size of 80 to 500 to polyethylene terephthalate or polybutylene terephthalate.
JP-A-50-129851 discloses that a molded product having an appearance with scattered metal powder can be obtained by incorporating ~15PI (R).However, a product based on such crystalline polyester It is difficult to obtain dimensional accuracy of the molded product, and thin-walled molded products may be deformed.If glass fiber is mixed in to eliminate this, the difference in refractive index between glass and polyester Since light is reflected and refracted at the interface between glass fiber and polyester, the reflected light from the mixed metal powder is disturbed.
The problem is that the shine is blurred. Furthermore, as having the same purpose, Japanese Patent Publication No. 42-22522 discloses that an ethylene-vinyl alcohol copolymer with a particle size of 74
Casting films and compression molded articles containing 10 to 50 pHRg of -88 micron metal powder have been disclosed, but the problem is that the copolymers are not suitable for injection molding or extrusion.

The third method is to obtain a molded product with conductivity and electromagnetic shielding properties by mixing a large amount (for example, 50 PHR or more) of metal in the form of flakes or fibers, but it is difficult to obtain a molded product with excellent appearance. Can not.

[Purpose of the invention]

The purpose of the present invention is to provide an excellent appearance that can be used for high-quality molded products with complex shapes such as camera exterior covers and VTR covers.
That is, the object of the present invention is to provide a resin molded product having an appearance like galaxies scattered and shining in a clear night sky (hereinafter referred to as galaxy-like).

[Disclosure of the invention]

The object of the present invention is achieved by the following resin molded product.

That is, 100 parts by volume of thermoplastic resin and 0.1 to 20 parts of arbitrarily shaped metal particles having a maximum outer diameter of 10 parts to 10 parts to 10 parts by volume.
The resin molded article is characterized in that the average gap between the metal particles and the weld width H are in a relationship of D≧H.

The shape of the metal particles is preferably spherical or flaky, but is not particularly limited.

The metal particles include, for example, aluminum, tin, copper, brass,
It is preferable to use metals such as stainless steel and iron, or alloys thereof, which have a metallic luster on the surface.

Further, regarding the size of the metal particles, if the maximum outer diameter is smaller than 10 scales, the metal particles will have a metallic appearance, and if the maximum outer diameter is larger than 1.0 mm, the metal particles will spoil the appearance balance with the resin. 10-~1
．． If it is 0 mm, it is much larger than the conventional one, so there is little difference in appearance between the layer with and without the metal particles 4, and the weld line 3 is hardly noticeable (FIG. 4). Preferably 1
It is 5 μs to 100 μs.

A resin made by melting and mixing 5% by volume of aluminum flakes with a side of 50 mm into polypropylene resin? When molding was performed at an injection pressure of 50 kg/crn', welds were not noticeable even when observed under a microscope.

The mixing ratio of metal powder is 0.1 to 20 parts by volume, preferably 0.3 to 12.0 parts by volume per 100 parts by volume of thermoplastic resin.
This is the capacity part.

If the volume part of the metal particles is less than 0.1 volume parts per 100 volume parts of the resin, the metal particles will look like foreign matter, and if it exceeds 20 volume parts, the appearance will become whitish. Within this range, there is almost no decrease in physical properties, strength, weather resistance, solvent resistance, etc.

For example, polycarbonate resin (manufactured by Ondai Kasei Co., Ltd., Panrai L 1225Y) and aluminum (manufactured by Toyo Aluminum Co., Ltd., FM
Figure 1 shows the physical properties when 1415) is added. Tensile rupture (TS), elongation (TE), flexural strength (FS), flexural modulus (FM) at molding temperatures of 280°C and 300°C
), impact value (1/8”Imp) with aluminum content 2.
Measurements were made for 0.4.0.6.0.8.0% by volume. As is clear from Figure 1, the resin molded product of the present invention exhibits physical property values sufficient to withstand use as exterior products such as cameras and VTRs. In addition, moldability is no different from that of ordinary resins.

From the above, the metal particles have a maximum outer diameter of 10-1. Omm
Therefore, 0.1 to 20 parts by volume is suitable for 100 parts by volume of resin.

Furthermore, in the molded product of the present invention, the average gap between the mixed metal particles and the width H of the weld line are expressed by the following formula (1
) It is necessary that the relationship of % formula % (1) is satisfied. When D is smaller than H, weld lines become noticeable.

Assuming that the metal particles are spheres, in a system where the distances between the centers of the spheres are all equally distributed, the average gap between the metal particles is calculated by the following formula (
2).

For example, Example 1. Conventional metallic mold metallic When 5% by volume of metal particles with a diameter of 2u+ is mixed D=3.46gm Example 2. Galaxy style mold metallic When 5% by volume of metal particles with a diameter of 50 mm are mixed D
= 3fli, 4dori is a conspicuous demonstration of the weld line, and D
When is large, the metal becomes sparse and the weld line becomes less noticeable.

The visibility of the weld line varies depending on the transmittance of light from the resin surface, the shape of the molded product, the gate position, etc., but the weld width H of a metallic mold is usually 5 to 30 microns. For this reason, as shown in Example 1, the value of D in the conventional metal-like molded metallic is smaller than the weld width H, so the weld is conspicuous, and it cannot be used for a high-class appearance with a complex shape.

From formulas (1) and (2), the volume ratio of metal particles is expressed by the following formula (3)
It is expressed as

The thermoplastic resin used in the present invention is, for example, an acrylic resin, a styrene resin, a vinyl chloride resin, a methylpentene resin, a polycarbonate resin, a copolymerized polyester, a copolymerized polyamide, or ABS, which are mixed together or colored. You can leave it there. However, polyethylene terephthalate and polybutylene terephthalate resins are not very suitable. Further, by mixing, for example, 0.1 to 12.0% by volume of a coloring agent into the resin molded article of the present invention, more diverse appearances can be formed. In addition, various stabilizers, mold release agents, antistatic agents, flame retardants, etc. can be added within a range that does not impair the effects of the present invention.

100 parts by volume of thermoplastic resin and 0.1 to 20.0 parts of metal particles
A volume part of the material mixed with additives such as a coloring agent, if desired, is molded by injection molding.

As the formation form of the above-mentioned weld line, the fifth and sixth
As shown in the figure, there are two types: a frontal collision weld line (Fig. 5) and a parallel weld line (Fig. 6). In the case of a head-on weld line, the energy in the flow direction is large, so the weld line becomes smaller or twisted during the collision and is less noticeable, but in the case of a parallel weld line, the weld line is formed parallel to the flow direction, so the weld line The energy to reduce the width is not working, and the weld line stands out in black. For parallel weld lines,
The weld width may reach 70-mm. In addition, 2 indicates a layer made only of resin, and 5 indicates the metal particle content.

Therefore, when designing the mold, by designing the gate so that parallel weld lines are not formed, it is possible to apply the method to products with even more complex shapes. For example, for a front cover of a camera, install two submarine gates at the positions A and B in Figure 7, for a VTR cover, install a side gate at position C as shown in Figure 8, and for a typewriter exterior cover. In this case, if a gate is provided at the position H as shown in FIG. 9, molding can be performed without forming parallel weld lines. 7 to 9, 6 is a front view, 7 is a right side view, 8 is a left side view, 9 is a top view, and 10 is a bottom view.

It has been said for some time that silver streaks, which are one of the appearance defects, are likely to occur when molding products with a metallic appearance. Silver streaks will not occur in the case of a galaxy-like appearance, as long as you do not allow too much time and do not lower the mold temperature too much.Also, in the case of a metal-like appearance, pinpoint gates are likely to cause silver streaks, but this is true. In the case of the galaxy-like appearance of the invention, silver streaks do not occur even with pinpoint gates.

Further, the resin molding of the present invention is not limited to injection molding, and may be a melt molding method such as extrusion molding or injection compression molding. In order to uniformly disperse the metal particles in the molded article, it is preferable to use a composition in which the thermoplastic resin and metal particles are mixed in advance by melting the resin, for example, in the form of pellets.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example 1 Polycarbonate resin (manufactured by Ondai Kasei ■) 92.3% by volume, aluminum particles (manufactured by Toyo Aluminum ■) 2.7% by volume
The camera front cover shown in FIG. 7 was injection molded under the following molding conditions using a material containing 3.7% by volume of colorants such as titanium oxide, dye red, and dye yellow.

The obtained molded product had a beautiful appearance resembling the glittering galaxies scattered in the night sky, without any weld lines or silver streaks that would impair its appearance.

Example 2 ABS resin (manufactured by Ube Saikon ■) 89% by volume, aluminum particles (manufactured by Toyo Aluminum ■) 6.5% by volume (average diameter 75%)
Using a material containing 4.5% by volume of a coloring agent such as titanium oxide, carbon black, or dye blue, the VT shown in FIG.
The R cover was molded under the following molding conditions.

The obtained molded article had an excellent appearance as in Example 1.

Example 3 PS resin (manufactured by Asahi Kasei ■) 87.8% by volume, aluminum particles (manufactured by Toyo Aluminum ■) 9.0% by volume (average diameter 100%)
The typewriter exterior shown in FIG. 9 was injection molded using materials containing 3.2% by volume of colorants such as titanium oxide, carbon black, and cyanine blue under the following molding conditions.

The obtained molded article had an excellent appearance as in Example 1.

〔Effect of the invention〕

The resin molded product of the present invention has a galaxy-like appearance that can be used for high-grade molded products such as camera exterior covers and VTR covers. The effect is particularly remarkable when dye-colored thermoplastic resin is used, and it can be applied to products with complex shapes.

Moreover, since the final molded product is made only by injection molding, the cost is low and productivity is high, making it extremely efficient.

[Brief explanation of the drawing]

FIG. 1 shows an example of the physical properties of the resin molded article of the present invention. FIG. 2 is a flow cross-sectional view of the metal powder-containing resin, FIG. 3 is a cross-sectional view of the metal powder-containing resin after molding, FIG. 4 is a cross-sectional view of the metal powder-containing resin of the present invention after molding, and FIG. FIG. 6 is a flow sectional view showing the formation form of a frontal collision weld line, and FIG. 6 is a flow sectional view showing the formation form of a parallel weld line. Figure 7 shows the camera exterior cover of the present invention, and Figure 8 shows the VTR.
Cover, FIG. 9 is a typewriter exterior cover. 1-m-metal powder 2--layer of only resin 3-m-weld line 4-m-metal piece 5-m-metal piece-containing layer 6-m-front view 7-m-right side view 8-1 1 Left side view 9--J 2-side view 10-11 Bottom view

Claims (1)

[Claims] Thermoplastic resin 100 volume parts and maximum outer diameter 10 μm ~ 1 m
0.1 to 20.0 parts by volume of metal particles of arbitrary shape, and the average gap D of the metal particles and the weld width H are D
A resin molded product characterized by a relationship of ≧H.