JP2003039441A - Resin-coated holding mold and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple molding mold which can form an uneven pattern and can be manufactured easily and a molding mold which can reduce biting. SOLUTION: In the molding mold capable of forming a three-dimensional shape in a molding, the smooth surface of the mold is coated with a synthetic resin in the three-dimensional shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die used for injection molding or press molding for imparting a three-dimensional shape to the surface of a plastic molded product, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in order to give a three-dimensional shape to the surface of a plastic molded product, a method of giving a three-dimensional shape to a molding die by a blast method or an etching method has been used.

Here, the blast method is to inject a sharp-angled abrasive or spherical abrasive on the surface of a molding die at high speed by using compressed air or centrifugal force, and by the impact action thereof. It is a method of carving a fine uneven pattern, means a sand blast method or a shot blast method, and is a satin finish method by a physical treatment. As the blast material, an alumina abrasive, a silicon carbide abrasive, glass beads, etc. are used. The etching method is a method of forming an exposed surface and a non-exposed surface on the surface of the molding die and melting the metal on the exposed surface to give a three-dimensional shape to the surface of the molding die.

Incidentally, in order to give a three-dimensional shape to the molding die, not only the above method but also a machining method such as grinding may be adopted.

[0005]

It is time-consuming and costly to give a three-dimensional shape to a surface by a machining method, and when processing a fine portion, a tool suitable for the fine portion is required. There was a problem such as

According to the blast method, it is necessary to use, as a molding die material, a die material having no material defects such as pinholes, rough scratches, and hardened layers. If the size of the blast particles is nonuniform, the three-dimensional shape of the molding die surface must be nonuniform, so the material and size of the particles to be sprayed must be taken into consideration. If there is an error, there is a problem that a desired three-dimensional shape cannot be formed on the surface of the molding die. In particular, since it is a physical impact treatment, there is also a problem that the satin finish shape and texture are subtly different depending on the hardness and toughness of the mold material.

The etching method has the drawbacks that the carving is shallow and the three-dimensional effect is poor, but the surface exposed to the processing liquid can be processed simultaneously, and a complicated curved surface or a large area can be processed. , Commonly used.
In addition, there is a problem that etching is required many times to give a three-dimensional effect, and it takes time to form a molding die.

Although the metal is dissolved in the etching process, since the dissolution of the metal is a chemical reaction,
It is difficult to control the dissolution of metal, and the surface to be dissolved cannot be uniformly dissolved. In addition, the metal of the die material has unique etching characteristics, and there is a problem that the etching shape, roughness, and gloss appear differently depending on the difference in chemical composition, structure, and grain size. There is also a problem that the texture and crystal grains change, and unevenness occurs. Furthermore, it is necessary to use a mold material having almost no material defects for a fine pattern such as a matte texture, and it is necessary to polish the fine texture to # 400 to # 600. On the other hand, in etching, once the metal is dissolved, there is a problem that it cannot be restored and cannot be redone.

Although both the blasting method and the etching method have the above-mentioned problems, they are generally used as a method for shaping a molding die. However, in these methods, the surface of the molding die is physically or chemically treated. In the blast method, polishing is required after the blast treatment, and also in the etching method, polishing treatment is similarly required. . When the polishing treatment is not performed, there is a problem that a so-called "stripping" phenomenon occurs and the molded product cannot be removed from the mold depending on the removal angle.

[0010]

Therefore, the inventor has accomplished the present invention as a result of earnest research to solve these problems. The molding die according to claim 1 of the present invention is a molding die, wherein the synthetic resin adheres to the whole or a part of the molding surface, and the synthetic resin is three-dimensional. And the molding die. The molding die according to claim 2 of the present invention is the molding die according to claim 1, characterized in that the synthetic resin is adhered by spray coating. The molding die according to claim 3 of the present invention is the molding die according to claim 1, characterized in that a synthetic resin is adhered by coating. In the mold according to claim 4 of the present invention, the synthetic resin is an epoxy resin,
The molding according to any one of claims 1 to 3, which is a resin composed of one or more kinds selected from a phenol resin, a melamine resin, a diallyl phthalate resin, a polyimide resin, a polyamideimide resin, and a fluorine resin. It is a mold. The molding die according to claim 5 of the present invention is characterized in that a solid material is mixed in the synthetic resin.
The molding die according to any one of claims 1 to 4. The molded article according to claim 6 of the present invention is a molded article characterized by being molded with the molding die according to any one of claims 1 to 5. The method for producing a molding die according to claim 7 of the present invention is characterized in that the synthetic resin is brought into close contact with the synthetic resin by spraying the synthetic resin to give a three-dimensional shape. is there. The method for producing a molding die according to claim 8 of the present invention is characterized in that a synthetic resin is adhered to give a three-dimensional shape by coating with a synthetic resin. Is.

The objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments of the invention given below with reference to the drawings.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a molding die characterized in that a molding surface of a molding die is provided with a three-dimensional synthetic resin layer. Such a three-dimensional shape has a synthetic resin layer. It is derived from. FIG. 1 shows a conceptual cross-sectional view which is an embodiment of the present invention. The synthetic resin layer 12 formed on the mold 101 having a smooth surface gives the surface of the molded product a three-dimensional surface shape corresponding to the synthetic resin layer 12. The surface of the mold 102 may be covered with a synthetic resin. That is, if the synthetic resin layer is regarded as a convex shape, the molded article is provided with a corresponding concave surface shape. The uneven surface shape may be applied to the entire surface, or the uneven surface shape may be applied only to a part of the surface. Depending on the shape of the uneven surface, it is referred to as leather grain or satin grain. Here, the leather grain is a wrinkle pattern found on the surface of leather, and is applied to automobile interiors and the like, for example, molded products such as steering handles, console boxes, meter panels, dashboards, and side moldings. . Here, the satin-finished grain refers to minute irregularities such as those found on the surface of the pear, and as the product subjected to the satin-finished grain, the exterior of home appliances, for example, a television, a cooler panel grill, a refrigerator panel, It is applied to molded products such as washing machine panels.

According to the present invention, since the surface of the molding die is three-dimensionally coated with the synthetic resin, it is not necessary to perform blast treatment, etching treatment or the like. Particularly, in the spray coating method, the molding die is used. It is possible to reduce the mold making time.

Further, the synthetic resin is present between the molded product and the molding die, the heat transfer coefficient of the synthetic resin is lower than that of the metal, and the molten resin to be molded is the metal directly. Since it does not come into contact with the molding die, the temperature drop of the resin to be molded is gentle, and welds are unlikely to occur.

Since the surface of the molding die is covered with the synthetic resin, the surface of the molding die can be prevented from being oxidized. Even if the synthetic resin coating has pinholes, the surface of the molding die is coated with the synthetic resin, so that the synthetic resin can be easily repaired or the synthetic resin can be used as a solvent. Since it can be easily removed by, for example, the molding die can be reused.

On the other hand, even though it is a synthetic resin, it may be affected depending on the operating temperature range. However, even when it is used at a temperature near the heat resistance limit, it does not melt like a metal, the synthetic resin becomes flexible, and it becomes easy to cope with deformation, so that galling is unlikely to occur.

The synthetic resin used here is required to have heat resistance, releasability, adhesion to a die material, abrasion resistance and the like. The heat resistance is preferably one that does not melt at least at 150 ° C. As abrasion resistance, resins used in injection molding, such as polypropylene resin and ABS resin (acrylonitrile-butadiene-styrene copolymer)
It is desirable to have sufficient resistance to the flow of melt such as. For example, it is desirable that the molding can withstand 1000 shots or more. In the manufacturing of molded products, many molded products are manufactured with the same mold.
Synthetic resins suitable for these include epoxy resin, phenol resin, melamine resin, diallyl phthalate resin,
Polyimide resin, polyamide-imide resin, fluorine resin, etc. are available. In the present invention, one selected from these synthetic resins is used.
A seed or a resin obtained by combining these is used. In addition, preferably, an epoxy resin, a polyimide resin, a polyamideimide resin, a fluorine resin, or a mixture thereof is used. As an epoxy resin, bisphenol A
Type, those using novolac, those using cyclopentadiene and cyclohexene derivatives, and the like. Examples of the polyimide resin include polyamino bismaleide and bismaleimide-triazine resin. Polyamideimide resins include those synthesized from trimellitic acid and pyromellitic acid. Examples of the fluorine resin include polyfluoroethylene, fluorinated ethylene-propylene copolymer, polytrifluorochloroethylene, and polyvinylidene fluoride.

Various additives may be added to these synthetic resins to increase their properties. For example,
A release agent for improving the releasability and a filler for improving the strength of the synthetic resin layer may be added to the synthetic resin. As the additive, a release agent, a cross-linking agent, an antistatic agent, a curing agent or the like is used. As the filler, alumina, silicon carbide whiskers, pigment or the like is used.

As a method of coating the surface of the mold with a synthetic resin, a method of spraying and coating a synthetic resin, a method of coating, a method of coating with a brush or the like, a method of coating the mold by dipping it in a resin liquid, etc. However, the present invention is not limited to these. From the viewpoint of improving productivity, the spray coating method and the coating method are preferable. In case of spray coating method or coating method, the resin layer is 10μm to 100μm
The thickness is 10 μm to 50 μm. When the thickness is 10 μm or less, it is difficult to coat the entire surface when the entire surface is coated, and when it is 100 μm or more, the three-dimensional shape may change.

Solid materials may be mixed in the synthetic resin layer formed by such a method. By mixing the solid matter, a three-dimensional shape can be easily formed. The solid may be a resin having the same component as the coating forming resin layer, or another resin that has already been cured, or may be a resin other than the synthetic resin, such as glass beads or metal powder. .

Examples of the metal used for the mold include not only steel materials such as pre-hardened steel, hardened steel, precipitation hardening steel and stainless steel but also non-ferrous metals such as zinc alloy, aluminum alloy and beryllium copper alloy. The invention is not limited to these. This is one of the features of the present invention.

The molding die may be subjected to a blasting treatment or an etching treatment to such an extent that the molded product is not affected, for example, the irregularities on the surface of the die cannot be visually observed. Further, corona discharge, ultraviolet irradiation, radiation irradiation, or the like may be performed as the surface treatment of the mold. By these treatments, the adhesiveness can be improved. For example, when the etching treatment is performed, the surface of the molding die has irregularities, and the coating resin penetrates into the recesses to generate an anchor effect, so that the adhesive strength is improved.

In the molded product by the molding die according to the present invention, since the surface property of the molded product is similar to that of the coated product, it is not necessary to further coat the molded product. That is, the surface of the molded product directly reflects the surface properties of the resin coating, unlike the reversal of the pseudo pattern itself such as etching. For this reason,
The surface texture retains the characteristics of the resin itself and at the same time retains the original texture. Further, since no painting is required, this molded product does not contain paint components and the like, and can be easily recycled.

In producing such a molding die, a synthetic resin is dissolved in a solvent, mixed with a curing agent, etc., and after having an appropriate viscosity, the metal is applied by a spray coating method or a coating method. It is made by coating the mold with a synthetic resin.

In the spray coating method, a mixed solution of a synthetic resin and a curing agent (viscosity of 10,000 to 100,000 centipoise) is sprayed with a spray gun at a spraying pressure of 1 to 7 kg / cm2, thereby spray coating. Work is done.

In the coating method, a mixed solution of a synthetic resin and a curing agent (viscosity of 10,000 to 100,000 centipoise) is coated by using an apparatus such as a bar coater.

The molding die surface-coated with the synthetic resin and the curing agent is heat-treated in a heating furnace at 100 to 180 ° C. for 1 to 2 hours in order to surely cure the synthetic resin.

The present invention will be described below with reference to examples.

[0029]

Example 1 100 parts by weight of an epoxy resin and 28 parts by weight of an amine curing agent were kneaded, and air bubbles remaining in the resin were removed by a defoaming treatment to be used as a coating resin.
Next, the coating resin was sprayed on the mold shown in FIG. 2 with an air gun, the resin was coated, and the mold was dried to coat the mold surface with the resin in an uneven pattern. Before coating the resin, the mold was washed with a solvent to remove oil, dust and the like adhering to the mold surface. Then, heat treatment was performed in a heating furnace to cure the resin. And after finishing inspection,
A molding die was obtained.

[0030]

Comparative Example 1 As a comparative example, a mold surface 52 having the same shape as that of FIG.
Was subjected to an etching treatment to prepare a molding die having an uneven pattern.

By Example 1 and Comparative Example 1, a molded product having a leather grain was obtained. However, in Example 1, even if the draft angle was 3 degrees, it was possible to pull out without scoring, but with etching, severe galling occurred, and in some cases the molded product could not be pulled out. The results are shown in Table 1.
Shown in. In addition, although the time required to manufacture the molding die by the spray coating method was 3 hours, the time required for manufacturing the molding die was 5 hours when the etching treatment was used. It was able to be greatly shortened.

[0032]

[Table 1]

The evaluation of the draft angle test results will be described below. "○": No shaving was observed and it could be easily removed. "△": Shavings were found in some parts, but could be removed. “×”: The sword was so severe that it could not be pulled out.

[0034]

According to the present invention, it is possible to obtain a molding die capable of forming an uneven pattern on a molded product.

[Brief description of drawings]

FIG. 1 is a conceptual cross-sectional view of a molding die that is an embodiment of the present invention.

FIG. 2 is a schematic view of a molding die used for measuring a draft angle.

[Explanation of symbols]

10 Mold for molding 101 Fixed mold (Cavity side) 102 Movable mold (core side) 20 resin layer

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[Procedure amendment]

[Submission date] July 16, 2002 (2002.7.1)
6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a molding die characterized in that a molding surface of a molding die is provided with a three-dimensional synthetic resin layer. Such a three-dimensional shape has a synthetic resin layer. It is derived from. FIG. 1 shows a conceptual cross-sectional view which is an embodiment of the present invention. By the synthetic resin layer 20 formed on the mold 101 having a smooth surface, a three-dimensional surface shape corresponding to the synthetic resin layer 20 is given to the surface of the molded product. The surface of the mold 102 may be covered with a synthetic resin. That is, if the synthetic resin layer is regarded as a convex shape, the molded article is provided with a corresponding concave surface shape. The uneven surface shape may be applied to the entire surface, or the uneven surface shape may be applied only to a part of the surface. Depending on the shape of the uneven surface, it is referred to as leather grain or satin grain. Here, the leather grain is a wrinkle pattern found on the surface of leather, and is applied to automobile interiors and the like, for example, molded products such as steering handles, console boxes, meter panels, dashboards, and side moldings. . Here, the satin-finished grain refers to minute irregularities such as those found on the surface of the pear, and as the product subjected to the satin-finished grain, the exterior of home appliances, for example, a television, a cooler panel grill, a refrigerator panel, It is applied to molded products such as washing machine panels.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayo Kawazoe             2-10-10 Nishiishikiri-cho, Higashi-Osaka City, Osaka Prefecture             Hanako Tanasawa Co., Ltd. (72) Inventor Hisao Aota             2-10-10 Nishiishikiri-cho, Higashi-Osaka City, Osaka Prefecture             Hanako Tanasawa Co., Ltd. F-term (reference) 4F202 AF01 AF15 AG05 AJ03 AJ09                       CA09 CA11 CD23 CK11

Claims (8)

[Claims] 1. A molding die, characterized in that a synthetic resin adheres to the whole or a part of the molding surface and the synthetic resin is three-dimensional. 2. The molding die according to claim 1, wherein the synthetic resin is adhered by spray coating. 3. The molding die according to claim 1, wherein the synthetic resin is adhered by coating. 4. The synthetic resin is one or more resins selected from epoxy resin, phenol resin, melamine resin, diallyl phthalate resin, polyimide resin, polyamideimide resin, and fluorine resin. The molding die according to any one of claims 1 to 3. 5. The molding die according to claim 1, wherein a solid substance is mixed in the synthetic resin. 6. A molded article, which is molded by the molding die according to any one of claims 1 to 5. 7. A method of manufacturing a molding die, comprising spraying a synthetic resin to bring the synthetic resin into close contact with the resin to give a three-dimensional shape. 8. A method for producing a molding die, which comprises applying a synthetic resin to bring the synthetic resin into close contact with the resin to give a three-dimensional shape.