JPH09239739A - Surface structure of molded object, molding thereof and mold surface finish processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded object having surface appearance to which a high grade feeling is imparted and a finish surface strong against a damage by providing gloss free regions and protruding parts scattered on the arears between the gloss free regions and protruding to the outside from the gloss free regions and having gloss. SOLUTION: An alundum polishing material is sprayed on the surface of a mold 10 from a blast nozzle to perform embossing processing. Glass beads are sprayed on the processed surface not only to impart gloss but also to form recessed parts 12 protruding from the outer surface of the mold. This mold 10 is used to perform the injection molding of an ABS resin to obtain a cabinet having an outer surface strong against a damage while keeping a matte feeling and having gloss contrast between uneven parts 17 and protruding parts and equipped with an outer surface having embosses feeling depth.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface structure of a molded article,
The present invention relates to the molding method and a finishing method of the surface of a molding die for molding the molded body.

[0002]

2. Description of the Related Art For example, in a cassette type tape recorder with a radio, a television receiver, an audio panel, etc., a cabinet made of an injection molded body of synthetic resin is used. Such a cabinet is manufactured by injecting molten ABS resin, high-impact polystyrene resin, or the like into the cavity of a mold having a predetermined shape, molding the mold, and then taking it out of the mold. In this case, if the surface of the cavity of the mold is smooth, the surface of the molded product is also smooth, and the cabinet has a poor sense of quality. Therefore, it has been attempted to give a high-grade appearance by coating the outer surface of the cabinet after molding. However, when painting is performed, the number of steps increases, which causes a cost increase.

Therefore, in order to impart a high-grade feeling to the molded product without applying the coating, the graining process and the blasting process are performed. The embossing and the blasting are performed by molding with the mold manufactured in the process shown in FIG. Here, the mold is processed by first forming fine irregularities 2 such as a satin pattern as shown in FIG. 6B on a smooth surface of the mold by sandblasting or etching as shown in FIG. 6A, and sand or sand on it. The glass beads are struck to remove the fluffiness of the minute unevenness 2, and the unevenness 3 having no edge is shown in FIG. 6C.
It is formed as shown in FIG.

[0004]

As described above, the mold used for performing the conventional embossing or blasting by molding is a chemical or sand, glass beads, etc. on the smooth surface of the mold 1 shown in FIG. 6A. 6B is a processing method for forming a pattern, but if the surface of the mold 1 is only roughened as shown in FIG. 6B, it is easy to get scratches, and glass beads are used for the purpose of preventing such scratches and for the purpose of final finishing. 6 has been used to remove the edge of the unevenness 2 and form the unevenness 3 having no edge as shown in FIG. 6C. However, according to such a method, the outer surface of the molded article is entirely glossed, which makes gloss adjustment impossible. Further, since the depth of the unevenness is constant, there is a problem that the effect on the scratching property is small.

Theoretically, the gloss can be adjusted as a whole by controlling the density of the glossy portion while glossing the concave portion of the pattern of the unevenness 3 and matting the other portions. In addition, the above method is also effective against scratches, but since the protruding part that becomes gloss on the outer surface of the molded product becomes a recess on the surface of the mold, it is not It was impossible to realize.

The present invention has been made in view of the above problems, and provides a molded article which gives a high-grade appearance to the surface of the molded article and has a finished surface that is strong against scratches. An object of the present invention is to provide a surface structure, a method for molding the same, and a method for finishing the surface of a mold for molding such a molded body.

[0007]

Means for Solving the Problems The present invention is composed of minute irregularities, and is scattered between a non-glossy portion and the non-glossy portion, and protrudes outward from the non-glossy portion to have a gloss. The present invention relates to the surface structure of a molded product that includes a protrusion and a protrusion.

The area ratio of the non-glossy portion and the glossy protrusion formed of the minute irregularities may be 10 to 90%: 90 to 10%.

The invention relating to the molding method is formed by a molding die having an inner surface on which minute irregularities are formed and smooth concave portions are scattered in the region where the minute irregularities are formed,
Forming minute unevenness on the outer surface, and a dull area and a glossy projection that is scattered between the dull areas and protrudes outward from the dull area. The present invention relates to a method for molding the surface structure of a molded body according to claim 1.

The invention relating to a method of finishing the surface of a molding die for molding such a molded article is a step of spraying an abrasive consisting of fine particles once or a plurality of times to form fine irregularities on the surface of the molding die. And a step of hitting glass beads having a predetermined grain size thereon to form recesses that are deeper and smoother than the minute irregularities and are scattered, and a method of finishing the surface of the mold.

Another invention of a method of finishing the surface of a molding die is the step of etching a satin pattern to form fine irregularities on the surface of the molding die and hitting glass beads of a predetermined grain size on the step. The present invention relates to a method for finishing a surface of a molding die, which comprises a step of forming concave portions which are deeper and smoother than minute irregularities so as to be scattered.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a method for finishing a die surface according to an embodiment of the present invention. The surface of the die 10 that has been finished smoothly (see FIG. 1A) has a grain size of A220-
The abrasive material of A20 is sprayed once or a plurality of times, thereby forming minute irregularities 11 having a satin pattern as shown in FIG. 1B on the surface of the mold 10. Then, by spraying glass beads having a grain size of G100 to G20 thereon, the concave and convex portions 12 having glossy unevenness as shown in FIG. 1C at an area ratio of 10 to 90%, preferably 20 to 80%.
Formed at a rate of.

More specifically, the surface of the die 10 to be finished is degreased, and the portions other than the necessary portions are masked and covered. Then, after this, for example, alundum abrasive grains for forming the minute irregularities 11 are sprayed.

In such spraying, the pressure is 1.0 to 8.0 kgf / cm for the alundum abrasive from the blast nozzle.
Spray evenly on the textured surface of the mold 10 with the pressure of ² .
Such an operation is repeated a plurality of times depending on the pattern. Then, the surface of the mold 10 loses its luster and becomes matte (matte). When it is desired to make the substrate semi-glossy by a pattern, small glass beads are sprayed after this to remove the edges of the minute irregularities 11 to make it semi-glossy.

After this, glass beads are sprayed to form the glossy concave portion 12 as shown in FIG. 1C.
That is, the glass beads are sprayed so that the concave portion 12 is formed within an area ratio of 10 to 90%, more preferably 20 to 80%. In such an operation, the glass beads # 40 to # 10 were pressed at a pressure of 1.0 to 8.0 kgf /
Spray in cm ² . The ratio of spraying is, for example, 20 to 80% of the base, depending on the appearance design. Then, by performing cleaning after this, as shown in FIG. 1C, minute unevenness 11 having no gloss and deep recesses 12 having gloss scattered between them are formed.

Another method uses etching for forming the minute irregularities 11. That is, a satin pattern is formed on the surface of a smooth mold 10 as shown in FIG. 1A by a photoresist method, a transfer method, a spray method or the like, and an etching process is performed. This operation is repeated 1 to 3 times to form a satin pattern. Then, after spraying the alundum abrasive grains thereon, the glass bead grain size is G100 to G2.
00 is sprayed in the range of 10 to 90%, preferably in the range of 20 to 80%, to form the large glossy concave portion 12.

To describe the processing by etching in more detail, the smooth surface of the mold 10 is degreased, and then masking for covering unnecessary portions is performed. Then, a satin pattern is applied and etching is performed. Such etching may be repeated multiple times depending on the pattern.

As a concrete method of etching, nitric acid added with an additive is used when the mold 10 is a steel material. Mold 10
When is copper-based or zinc-based, a ferric chloride solution containing an additive is used as an etching agent.

In the etching, that is, the method of corrosion, after the pattern is transferred to the mold, the mold is immersed in an etching solution, and etching is performed while stirring. The etching rate is preferably 3 to 20 μm / sec, and the etching temperature is preferably in the range of room temperature to 35 °.

After this, as in the case of the blasting, the glass beads are sprayed.
40 to # 10 glass beads in an amount of 1.0 to 8.0 kgf /
Spray with a pressure of cm ² . The ratio of spraying is 10 to 90% of the base, more preferably 20 to 80, depending on the appearance design.
%.

As shown in FIGS. 2 and 3, the molded body 16 molded by the mold 10 having such a surface structure has a small outer surface which is in contact with the processed surface of the mold 10. In addition to having such unevenness 17, protrusions 18 having a gloss that protrudes toward the outer surface side are formed so as to be scattered between such minute unevennesses 17. Even when the finger nail comes into contact with the outer surface of the molded body 16 as shown in FIG.
Since the projection 18 having a gloss prevents the contact of the nail with the minute irregularities 17, the surface structure is more resistant to scratches, especially nail scratches, as compared with the conventional textured molded article having a matte feeling. Become.

Further, since the outer surface of such a molded body 16 has a contrast between a matte portion formed by minute irregularities 17 and a projection 18 having gloss and projecting to the outer surface side, it is common. Compared to texture, it gives a feeling of depth that is closer to that of a two-component textured paint. When the conventional processing method as shown in FIG. 6 is performed in the vicinity of the parting of the mold 1, galling is often generated, and even if a matte texture is used in the design, the glass bead suffers from this galling problem. There was no choice but to hit the to eliminate the matte feeling or to make the grain itself shallow.
On the other hand, in the case of the present invention, in which the protrusions 18 only have a gloss, unlike the method of hitting glass beads on the whole, a considerable mat portion can be left, so that the problem of galling can be avoided. It is also possible not to lose the matte feeling.

In addition, since the conventional textured design has no depth feeling and no gloss difference as compared with the textured finish of painting,
I couldn't expect a three-dimensional effect. However, according to the embossing of the present embodiment, it becomes possible to form unevenness with contrast on the outer surface of the molded body, so that it is possible to create a three-dimensional effect and depth even though it is embossing.

The surface structure of such a molded article can be widely applied to a relatively large cabinet, and can be widely applied to a cassette type tape recorder with a radio, a television receiver, an audio panel and the like. Further, such a structure makes it possible to omit coating for giving a high-class feeling to the outer surface of the molded body, and thus contributes to shortening of the manufacturing process and cost reduction.

The depth of the recess 12 formed on the surface of the mold 10 shown in FIG. 4 or the height h ₁ of the protrusion 18 formed on the molded body 16 shown in FIG. 5 to 300 μm, although it varies depending on the injection pressure, etc.
Is preferably within the range. On the other hand, the height h ₂ of the minute irregularities 17 is preferably in the range of 1 to 40 μm. In addition, the ratio of the area between the minute irregularities 17 and the glossy protrusions 18 formed on the surface of the molded body 16 is 10
~ 90%: 90 to 10%.

As described above, the molded product according to the present embodiment has a very large application in terms of improving the texture, and is an accessory for various electronic devices, headphones, and a cassette tape recorder with a radio. ,
It is widely applicable to cabinets and casings of various products such as audio devices, television receivers, laptop electronic devices, and telephones. Further, when a resin material mixed with metal powder, that is, a so-called metallic material is used, a more realistic metallic feeling than the current texture is obtained.

[0027]

Example 1 A surface of a steel mold 10 was sprayed with a bauxite alundum abrasive (A600) at a pressure of 5.0 kgf / cm ^{2 by} a blast nozzle to perform embossing. Then, from above the glass beads # 20, the pressure is 5.0 kgf /
By spraying with cm ² , a concave portion 12 having a glossiness and protruding to the outer surface was formed in an area of 40% in area ratio.

The mold 1 thus surface-treated.
0, ABS resin was injection-molded to mold a cabinet of a cassette tape recorder with a radio. Such a cabinet has an outer surface that is strong against scratches while maintaining an appropriate matte feeling, has a gloss contrast between the unevenness 17 and the protrusions 18, and has an outer surface that has a texture that gives a sense of depth. was gotten.

Example 2 A matte pattern was transferred to a predetermined position on the inner surface of a mold 10 made of steel, and the mold was immersed in nitric acid containing an additive,
The surface was etched by stirring. The etching rate was 10 μm / sec and the etching temperature was 20 ° C.
And

When an ABS resin was injection-molded in the cavity of the mold thus obtained to mold a cabinet of a cassette type tape recorder with a radio, a suitable matte feeling was maintained and resistance to nail scratches was maintained. A cabinet with textured outer surfaces was obtained. In particular, due to the contrast of gloss between the irregularities 17 and the protrusions 18, the depth can be felt, and a cabinet having a sufficiently high-grade appearance without painting is obtained.

[0031]

INDUSTRIAL APPLICABILITY As described above, the present invention is composed of minute unevenness and is scattered between the non-glossy portion and the non-glossy portion.
The present invention relates to a surface structure of a molded body in which a glossy protrusion protruding outside a non-glossy portion is formed on an outer surface, and a molding method thereof.

Therefore, it is possible to obtain a molded product having a surface structure that is strong against scratches while maintaining an appropriate matte feeling. In addition, there is a contrast of gloss on the outer surface due to the minute unevenness with no gloss and the protrusion with gloss, which makes it possible to reveal the appearance that feels the depth, and shortens the manufacturing process by omitting the painting process. And cost reduction can be achieved.

Such a surface structure of the molded body or a molding method is achieved by spraying an abrasive material or performing minute unevenness processing on the surface of the molding die by etching, and performing a step of hitting glass beads thereon. It is manufactured by a mold that has undergone a finishing process. Therefore, simply by adding a relatively simple finishing process to the surface of the mold,
A molding die for high-value-added molding can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing the surface processing of a mold.

FIG. 2 is an enlarged sectional view of an essential part showing the surface of a molded body that has been molded.

FIG. 3 is an enlarged cross-sectional view of a main part of a molded body showing an operation of preventing nail scratches.

FIG. 4 is an enlarged sectional view of an essential part showing the structure of the surface of the mold.

FIG. 5 is an enlarged sectional view of an essential part showing the structure of the surface of the molded body.

FIG. 6 is a vertical cross-sectional view showing conventional embossing of a die.

[Explanation of symbols]

1 ... Mold, 2 ... Micro unevenness, 3 ... Edgeless unevenness, 10 ... Mold, 11 ... Micro unevenness, 12 ... Recess, 16 ... Molded body, 17 ... Micro Unevenness, 18 ... Glossy protrusion

Claims (5)

[Claims] 1. A fine unevenness, which is provided with a non-glossy portion, and a projection which is scattered between the non-glossy portions and which projects outward from the non-glossy portion and has a glossiness. Surface structure of the molded body. 2. The area ratio between the non-glossy portion and the glossy protrusion, which is composed of the minute irregularities, is 10 to 90%: 90 to 10%. Surface structure of the described molded article. 3. A part which is formed by a mold having an inner surface on which fine irregularities are formed and which has smooth concave portions scattered in the region where the fine irregularities are formed, and which is composed of fine irregularities and has no gloss And a method for forming a surface structure of a molded article, wherein: the projections having a gloss, which are scattered between the non-glossy parts and project outward from the non-glossy parts, are formed on the outer surface, respectively. . 4. A step of spraying an abrasive consisting of fine particles once or a plurality of times to form fine irregularities on the surface of a molding die, and by hitting glass beads of a predetermined grain size on the fine irregularities. A process for forming deep and smooth recesses in a scattered manner, and a method for finishing the surface of the mold. 5. A step of forming fine irregularities on the surface of a mold by etching a satin pattern, and hitting glass beads having a predetermined grain size on the fine irregularities to form concave portions that are deeper and smoother than the fine irregularities. And a finishing process for the surface of the mold.