JP2001323089A - Fiber-reinforced thermoplastic resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a coating film free from float of filler, bubble, foaming which are defects of appearance of coating without exposing holes having micron order and reinforcing fiber on the surface. SOLUTION: This fiber-reinforced thermoplastic resin molded product is obtained by providing a coating film having 0.5-10 μm arithmetical average roughness Ra and 1-100 μm (as maximum height Ry) unevenness of surface roughness on at least part of the surface of the resin molded product composed of a thermoplastic resin composition containing a reinforcing fiber and having a surface roughness of <=2 μm arithmetical average roughness Ra and <=10 μm maximum height on the surface of unevenness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for products requiring strength, such as home information appliances, portable devices, optical devices, and precision devices.
The present invention relates to a fiber-reinforced thermoplastic resin molded article in which at least a grain portion is beautifully painted.

[0002]

2. Description of the Related Art In appearance parts such as a camera housing, a metal is processed or molded into a predetermined shape, and then the surface thereof is painted to give a high-class appearance. For example, when an aluminum alloy is used, the aluminum alloy formed into a predetermined shape is subjected to black alumite treatment, and a matte black coating is applied to a portion serving as an appearance portion, thereby giving a sense of quality.

On the other hand, due to the demand for smaller and lighter products,
Many metal parts are replacing plastic parts. These plastic parts use a molding material in which reinforcing fibers are previously kneaded in a resin in order to impart strength. In addition, this molding material is formed by injection molding to accurately and accurately form a complicated shape of a part. Since the molding surface of these plastic parts is a paint base, a beautiful appearance is not required.
For this reason, the surface of the mold for molding these may be in a minimum state that does not affect the appearance of the coating, and may be partially polished as necessary. Further, the coating on the plastic parts is performed by spraying a coating material containing an organic solvent in the same manner as the coating on the metal parts.

[0004]

However, since the surface of the mold used for molding the resin containing the reinforcing fibers is flat when viewed on the order of microns, the reinforcing fibers kneaded in the resin are hardened by the mold. And the reinforcing fiber comes out on the surface of the resin molded product. In addition, at the site where the filling of the resin is delayed in injection molding, that is, at the concave portion and the weld portion of the mold, the flow of the resin is disturbed, so that the direction of the reinforcing fiber is different, and a part of the fiber becomes part of the resin molded product. Protruding from the surface. When the molded product having the reinforcing fibers exposed on the surface is coated as described above, the reinforcing fibers may protrude from the surface of the coating film, and an appearance defect of “floating filler” may occur. In particular, when using a paint containing a strong organic solvent that has the effect of softening and dissolving the resin,
Filler floating is likely to occur.

[0005] In addition, the concave portion and the weld portion of the mold are
The gas remaining in the mold is concentrated to form fine bubbles, and a large number of micron-order holes with reinforcing fibers on the surface of the resin molded product are generated. When coating is performed on a molded product in which such holes are formed, air remains inside the holes, and when heated in a drying oven, the air expands and causes "hours", "foaming", etc. Bad appearance has occurred.

The floating of the filler can be repaired by removing it with a sandpaper and then repainting it. However, the number of steps increases and the cost increases. On the other hand, even if the foam and foam are repainted in the same manner, the repair is practically impossible because pores of the order of microns remain and the foam or foam recurs.

Japanese Patent Application Laid-Open No. 9-174565 has been made in order to solve the above-mentioned problems, and has a nest made of a material having low thermal conductivity such as glass and ceramic and a restraint for suppressing the end of the nest. The plate is located in the mold cavity. By molding a thermoplastic resin containing reinforcing fibers into a mold having such a structure, the protrusion of the reinforcing fibers is suppressed.

However, in the above publication, it is necessary to incorporate a nest or a holding plate into a mold, and the structure is complicated and the assembling is troublesome. In addition, in order to perform molding well, it is necessary to assemble with high precision, and the operation involves difficulty. Furthermore, even with the above-described structure, there is a problem that it is not possible to prevent bubbles and bubbles caused by residual gas.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a fiber having a coating film free of filler floating, millet and foaming, which has poor coating appearance, even when a mold having a simple structure is used. An object is to provide a reinforced thermoplastic resin molded article.

[0010]

Means for Solving the Problems] To achieve the above object, the invention of claim 1, made of a thermoplastic resin composition containing reinforcing fibers, the arithmetic mean roughness R _a in at least part of the surface 0 0.5 to 10 μm, maximum height _Ry is 1 to 100 μm
m, and the surface of the grain has an arithmetic average roughness _Ra of 2 μm or less and a maximum height _Ry of 10 μm.
A coating film having a surface roughness of not more than μm is provided.

As described above, by limiting the roughness and height of the grain and the coating film, micron-order holes and reinforcing fibers do not appear on the surface of the molded product. No foaming occurs. Therefore, molding using a mold having a simple structure becomes possible.

[0012] Incidentally, the arithmetic mean roughness _{R a} of the grain is 0.5μ
When it is smaller than m, the grain is too small and becomes a surface state close to a smooth surface, so that it is impossible to prevent protrusion of reinforcing fibers and generation of micron-order holes. Also, when the maximum height _Ry is larger than 100 μm, the grain is too large and cannot be covered so as to hide the mountain portion of the grain by one coating, so that a beautiful painted surface cannot be obtained, It becomes difficult to remove the molded product from the mold during molding. In addition, when dimensional accuracy is required when the part has a complicated shape or has sharp edges or protrusions,
These shapes cannot be satisfied.

The surface of the grain of the molded article is painted, and the surface roughness has an arithmetic average roughness _Ra of 2 μm or less and a maximum height _Ry of 1 μm.
By providing a coating film having a thickness of 0 μm or less, the roughness of the grain can be prevented from appearing in the appearance. Although the thickness of this coating film may be small, the grain is not uniform over the entire surface. For example, when there is an extremely high peak due to a flaw or the like in the part, a film thickness enough to fill the peak is required.

According to a second aspect of the present invention, in the first aspect of the present invention, the thermoplastic resin composition comprises a thermoplastic resin comprising a polycarbonate resin and / or an ABS resin.
It is characterized by containing 5 parts by weight to 100 parts by weight of reinforcing fibers composed of glass fibers and / or carbon fibers with respect to 0 parts by weight.

According to the present invention, fine grain can be formed, and the strength, dimensional stability and fluidity of the resin at the time of molding can be ensured.

[0016]

FIG. 1 is a sectional view showing a surface of a grain portion of a fiber-reinforced thermoplastic resin molded product 1 according to an embodiment of the present invention. The fiber-reinforced thermoplastic resin molded article 1 is molded into a predetermined shape by filling a mold with a thermoplastic resin composition into which reinforcing fibers are kneaded.

In FIG. 1, reference numeral 7 indicates a surface of the molded fiber-reinforced thermoplastic resin molded article 1 before the coating film 4 is formed. The surface 7 has a textured surface 2 formed at the same time as the molding of the molded product. The grained surface 2 has an arithmetic average roughness R
_a is 0.5 to 10 μm and the maximum height _Ry is 1 to 100 μm
It is formed so as to have a surface roughness of. The reinforcing fiber 3 is in point contact with the valley portion 8 of the grain surface 2. The coating 4 covers the top 5 of the grain. The surface roughness of the coating film 4 is such that the arithmetic average roughness _Ra is 2 μm or less and the maximum height R _y
Is formed to be 10 μm or less. In FIG. 1, the surface of the coating film 4 is represented as a plane, but this is because the surface roughness described above can be ignored compared to the surface roughness of the grained surface 2.

Such a fiber-reinforced thermoplastic resin molded product 1
Since the surface of the coating film 4 has a high-grade appearance, it is suitable for external parts of a main body such as a camera, binoculars, and a magneto-optical recording device.

The resin used for the fiber-reinforced thermoplastic resin molded article 1 is not particularly limited as long as it is a thermoplastic resin. Examples of the thermoplastic resin include general-purpose resins such as vinyl resins, styrene resins, olefin resins, acrylic resins, acrylonitrile-butadiene-styrene resins (ABS) and polyamide resins (PA), polycarbonate (PC), polyacetal ( POM), polyester (PET, PBT, etc.), polyphenylene sulfide (PPS), polyether ether ketone (PEE)
K), engineering plastics such as polysulfone, polyethersulfone, polythioethersulfone, polyarylate, and polyimide, and polymer alloys of these thermoplastic resins can be used.
Among them, PC, ABS and PC / ABS polymer alloy are easy to form fine grain, and especially, PC
Has good environmental resistance, rigidity, strength, and moldability, and thus can be suitably used as the fiber-reinforced thermoplastic resin molded article 1.

As the reinforcing fibers (fillers) used in the fiber-reinforced thermoplastic resin molded article, either inorganic or organic fillers can be used. The shape may be plate-like, spherical, fibrous or irregular. Specifically, natural silica such as quartz, synthetic silica produced by a wet or dry method; natural silicate such as kaolin, mica, talc, asbestos; synthetic silicate such as calcium silicate and aluminum silicate; magnesium hydroxide; Metal hydroxides such as aluminum hydroxide; metal oxides such as alumina and titania; metal carbonates such as calcium carbonate; metal powders such as aluminum, bronze and stainless steel; carbon black; glass fibers, carbon fibers, aramid fibers, and alumina Fibrous substances such as fibers; polymeric liquid crystal substances; potassium titanate whiskers, magnesium sulfate whiskers, aluminum borate whiskers, calcium carbonate whiskers,
Magnesium borate whisker, zinc oxide whisker,
Whiskers such as silicon carbide whiskers, silicon nitride whiskers, sapphire whiskers, and beryllia whiskers can be used. Among these, preferred are titania, stainless steel powder, carbon black, glass fiber, carbon fiber, aramid fiber, alumina fiber and potassium titanate whisker, and particularly preferred are glass fiber and carbon fiber, Preferred is a diameter of 5 to 50 μm and a length of 20 to 1000 μm
m glass fiber, diameter 2-20 μm, length 20-100
It is a carbon fiber of 0 μm.

These filler components may be surface-treated with a surfactant, a coupling agent or the like. The fillers may be used alone or in combination. Various fillers can be appropriately selected from commercially available ones.

In this embodiment, the thermoplastic resin 100
By molding using a thermoplastic resin composition containing 5 parts by weight or more of glass fiber and / or carbon fiber with respect to part by weight, strength and dimensional stability can be ensured in the molded product. Further, by reducing the amount of glass fiber and / or carbon fiber to 100 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin, it is possible to suppress a decrease in resin fluidity and a decrease in dimensional accuracy, which are characteristics required for injection molding. In addition to this, it is possible to suppress molding defects such as a short circuit at a concave portion of a mold in which the flow of the resin tends to be stagnant. To ensure a good balance between the strength and dimensional stability of the molded product and the fluidity of the resin at the time of molding, the glass fiber and / or carbon fiber should be in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the thermoplastic resin. It is more desirable to do.

Not limited to these glass fibers and carbon fibers,
Metal fillers such as stainless steel and inorganic fillers such as titania can be used in the same manner. Further, other than the purpose of increasing the strength, a coloring material such as a pigment, a dye, and aluminum powder, a release agent, an antistatic agent, and the like can be kneaded.

[0024] As means for coating the coating film, spray coating with a spray, brush coating, coating with a roller and the like can be used. Among them, preferred is spray coating, which can easily obtain a beautiful and even painted surface. Examples of paints that can be used in the painting process include paints that are generally widely used, for example, acrylic paints, epoxy paints, polyester paints, urethane paints, acrylic / urethane paints, alkyd paints, and the like. Can be used. Preferred among these are acrylic paints and two-pack acrylic / urethane paints.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Embodiment 1 FIG. 2 shows a camera frame 10 as a fiber-reinforced thermoplastic resin molded product. This mirror frame 1
Numeral 0 is a component for holding the lens inside, and the entire outer surface exposed to the outside is a textured surface 6, and
The textured surface 6 is coated.

In this embodiment, HN3000G (textured by Nihon Etching Co., Ltd.) was machined on the mold surface of the injection mold in order to form fine irregularities on the surface of the lens frame 10 as a molded product. Then, injection molding was performed in a mold using "Iupilon CGF-0505" (manufactured by Mitsubishi Engineering-Plastics Corporation) as a thermoplastic resin composition. This thermoplastic resin composition is a polycarbonate resin containing 5% by weight of glass fiber and 5% by weight of carbon fiber. When this resin composition is injection-molded, a grain having an arithmetic average roughness _Ra of 0.5 μm and a maximum height _Ry of 4.6 μm is formed on the grained surface 6 of the molded product released from the grained portion of the mold. Been formed. The arithmetic average roughness _Ra and the maximum height _Ry are determined by a method defined by JIS B0601,
It was determined using Talysurf.

Thereafter, the surface of the molded article (textured surface 6) is coated with Neo Alex 25 (trade name, manufactured by Nippon Kako Paint Co., Ltd.), which is a two-pack type acrylic / urethane-based paint.
The coating process was completed by drying at 30 ° C. for 30 minutes, and a lens frame 10 as a finished product was created. Arithmetic mean roughness _{R a} in this case the coating surface 0.1 [mu] m, maximum height _{R y} is 1.0 .mu.m, the thickness of the coating film was 10μm in average. Observation of the painted surface of the lens frame 10, which was the obtained fiber-reinforced thermoplastic resin molded product, showed a high-grade appearance without filler floating, millet and foaming.

(Examples 2 to 5) In Examples 2 to 5, the molding and coating of the lens barrel 10 of the camera were performed in the same manner as in Example 1. In this case, the embossing of the mold surface of the injection mold was performed using HN3006G in Examples 2 and 4, and HN in Example 3.
N3013G, and HN3002G in Example 5 (both are embossed by Nihon Etching Co., Ltd.). The resin composition to be molded is as follows. Example 2: Trade name "Panlite B-7130R (manufactured by Teijin Chemicals Ltd.)" This composition is a polycarbonate resin containing 30% by weight of carbon fiber. Example 3; trade name "Iupilon GS-2050MKR"
P825 (Mitsubishi Engineering Plastics Corporation)
This composition is a polycarbonate resin containing 50% by weight of glass fibers. Example 4: Trade name "DENKA ABS GR-0520G"
(Electrical Chemical Industry Co., Ltd.) "This composition is an ABS resin containing 20% by weight of glass fiber. Example 5; Trade name "Iupilon GMB-2020N (manufactured by Mitsubishi Engineering-Plastics Corporation)" This composition part is a PC / ABS polymer alloy containing 20% by weight of glass fiber.

On the surface of the molded product released from the embossed portion of the mold, Examples 2 and 4 show that the arithmetic average roughness _Ra is 2.4.
μm, the maximum height _Ry is 18.6 μm, Example 3 is also 3.3 μm, 28.6 μm, Example 5 is 0.8 μm,
A 6.9 μm grain was formed.

The paint used for coating the molded articles of Examples 2 and 5 and the drying conditions are the same as in Example 1, but the paint of Example 3 is a two-pack type acrylic / urethane-based paint "trade name" And dried at 70 ° C. for 30 minutes using “HIUREX P” (manufactured by Musashi Paint Co., Ltd.). The paint of Example 4 was used at a temperature of 80 ° C. and a temperature of 3 ° C., using a product name “Neo Alex 20 (manufactured by Nippon Kako Paint Co., Ltd.)” which is a two-pack type acrylic paint.
It was dried under the condition of 0 minutes.

The arithmetic average roughness R _a of the coating film surface of Example 2
The maximum height R _y and the average thickness of the coating film are each 0.1 μm.
m, 2.0 μm, 10 μm, and Example 3 was 0.2 μm.
m, 4.5 μm, 20 μm, Example 4 was 0.1 μm,
3.2 μm, 20 μm, Example 5: 0.1 μm, 2.7
μm and 10 μm. Observation of the painted surfaces of the obtained lens frames 10 of Examples 2 to 5 revealed that all of them had a high-grade appearance without filler floating, millet and foaming.

(Comparative Examples 1 to 5) As Comparative Examples 1 to 5, molding and painting were performed under the same conditions as in Examples 1 to 5, respectively, to produce lens frames. As a mold for injection molding, one manufactured by electric discharge machining was used. This mold does not have a grained surface on the mold surface.

If there is unevenness in the mold such as a step on the mold surface and this unevenness is transferred to the molded product and affects the appearance of the coating, it is polished and removed. When the painted surfaces of the obtained lens barrels of Comparative Examples 1 to 5 were observed, in all cases, filler floating, millet, and foaming were observed.

[0035]

According to the first aspect of the present invention, pores on the order of microns and reinforcing fibers do not appear on the surface of the molded article, so that floating of the filler, foam, and foaming, which are poor in the appearance of coating, do not occur. Therefore, molding can be performed using a mold having a simple structure, repainting is not required, and cost can be reduced.

According to the second aspect of the present invention, fine grain can be formed, and the strength, dimensional stability and fluidity of the resin at the time of molding can be ensured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the lens barrel of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fiber-reinforced thermoplastic resin molded article 2 Textured surface 3 Reinforcing fiber

Claims (2)

[Claims] 1. A surface roughness comprising a thermoplastic resin composition containing reinforcing fibers, wherein at least a part of the surface has an arithmetic average roughness _Ra of 0.5 to 10 μm and a maximum height _Ry of 1 to 100 μm. together with the grain, an arithmetic mean roughness R _a in the surface of the grain is 2μm or less, the maximum height R _y is fiber-reinforced thermoplastic resin which is characterized in that a coating surface roughness of less than 10μm Molding. 2. The thermoplastic resin composition contains 5 parts by weight to 100 parts by weight of a reinforcing fiber made of glass fiber and / or carbon fiber with respect to 100 parts by weight of a thermoplastic resin made of polycarbonate resin and / or ABS resin. The fiber-reinforced thermoplastic resin molded product according to claim 1, wherein the molded product contains a part of the thermoplastic resin.