JP3284291B2 - Injection molding simultaneous painting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for an injection molding apparatus for performing painting simultaneously with injection molding, and an associated mechanism.

[0002]

2. Description of the Related Art Conventionally, in order to perform painting simultaneously with injection molding, generally, before painting, a painting sheet of a thermoplastic synthetic resin is preformed by a vacuum suction molding method using a female mold before injection molding. By closing the female mold and the male mold and injecting the molten resin from the male mold side, the above-mentioned painted sheet is fused to the surface of the molded product of the injected resin. (See Japanese Patent Publication No. 50-19232 and Japanese Patent Publication No. 63-6339)

[0003] In addition, a thermoformed transfer sheet on which an arbitrary pattern is printed is used in place of the above-mentioned pictorial sheet, and a molded article is formed in the same manner as the above molding method. Then, the transfer sheet is peeled off from the molded article. Transferring patterns is also practiced. (See JP-B-51-33456)

[0004]

In these painting methods, a flat painting sheet or a transfer sheet (hereinafter, referred to as a sheet) is developed along a three-dimensional curved surface, so that the painting method is like a cylindrical surface. Apart from the specific case, there is a drawback that the sheet is partially distorted and the sheet is torn or wrinkled. In particular, a molded article having a curved surface having a large change in curvature even though it looks like a smooth curved surface like an egg surface tends to cause local wrinkles.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that wrinkles caused by changes in the curved surface are formed on the surface of the cavity product opposite to the surface of the cavity (for example, a concave surface). It has been found that by providing a portion having a curved surface (a convex curved surface), the distortion of the sheet can be absorbed.

That is, according to the present invention, after a sheet is placed in a mold, the sheet is brought into close contact with a molding curved surface of the mold by evacuation, and then molten resin is injected to fuse the sheet to the resin. In a mold apparatus for simultaneous molding and painting, on a divided surface of a mold having a molding curved surface on which a sheet is to be placed,
This is a mold device for simultaneous injection molding and painting, which is provided with a portion having irregularities opposite to the molding curved surface.

In a female mold having a concave curved surface on which a sheet is formed along a sheet, a protruding portion is protruded at a portion of the divided surface in contact with the cavity. A concave portion into which the convex portion can be fitted is provided at a position facing the convex portion.

The protrusion may be formed integrally with the mold, or may be detachably formed. Further, it is preferable to provide a clamping mechanism provided with a pushing blade for causing the sheet to follow the forming curved surface prior to evacuation. Further, a ventilation groove for applying a vacuum to make the sheet conform to the forming curved surface may be formed in the cavity surface and / or the division surface.

Therefore, the present invention will be described in detail below.
FIG. 1 is a perspective view showing an example of a product to be molded according to the present invention, and FIGS. 2, 3, and 4 are AA sectional view, BB sectional view, and CC sectional view of FIG. 1, respectively. It is. 1 to 4
As can be understood from FIG. 1, the product 1 has a three-dimensional curved surface and A
-A section, BB section, and CC section are all curved, and the change in the curvature in the CC section is larger than the change in the curvature in the BB section.

If such a product is simultaneously painted by injection molding, wrinkles 4 often occur on the sheet surface to be adhered, as shown in FIG. The present invention provides a mold device that prevents such wrinkles from occurring.

The mold apparatus according to the present invention has a mold dividing surface (parting surface) having a curved surface on which a sheet is to be placed.
In addition, there is provided a portion having irregularities opposite to the curved surface. For example, if the curved surface along which the sheet extends is a female mold having a concave curved surface, a convex ridge is provided on the divided surface, that is, a part that is not a product in accordance with the magnitude of the curvature of the cavity and the degree of the change, and the male mold is provided. A concave portion into which the convex portion can be fitted is provided at a position facing the convex portion on the mold dividing surface.

Although the shape of the convex portion is arbitrary, it is usually a gently sloped mountain shape continuous with the curved surface of the cavity, and the size of the convex curved portion is determined by the change in the curvature of the concave curved surface along the cavity sheet and the size of the sheet to be used. Determined in consideration of elongation. The position where the convex ridge is provided is a position close to a position where the curvature of the cavity is largely changed, and usually one position is sufficient. However, the shape of the molded product has a change in the curvature changed like a bump of 2 camels. If there are two large portions, they may be provided on a line connecting them and at two locations facing each other with a cavity therebetween.

As the sheet that can be used in the present invention, a transfer film or a laminate film can be used, and the base material thereof is polyester such as biaxially stretched polyethylene terephthalate or polybutylene terephthalate, or polyolefin such as polypropylene or polyethylene. Styrene-based resins such as polystyrene and ABS, and thermoplastic resin films such as polyvinyl chloride are preferred.

The thickness of the film is preferably 25 to 500 μm. Further, as the ink for forming the picture layer of these sheets, an ink containing a vinyl chloride-vinyl acetate copolymer, acryl, polyester, polyurethane or the like as a main component can be used. In addition, a clamp mechanism that assists the sheet along the cavity surface is provided as an auxiliary mechanism for the mold. This clamp mechanism forcibly pushes the sheet into the cavity before the sheet is sucked by the cavity, and the contact surface with the sheet is formed in a shape matching the molding surface of the cavity.

[0015]

According to the present invention, there is provided a mold apparatus for simultaneous painting with injection molding, in which a divided surface of a mold having a molding surface on which a sheet is to be formed is provided with a portion having irregularities opposite to the molding surface. Therefore, the sheet is locally extended due to the reverse unevenness, which prevents wrinkles from being generated in the sheet having the formed curved surface.

In addition, a clamping mechanism provided with a pushing blade for forcibly pushing the sheet so that the sheet follows the forming curved surface prior to the evacuation is attached to the mold apparatus. Wrinkles that are easy to wrinkle are prevented by this,
Subsequent evacuation ensures that the sheet conforms to the formed curved surface.

Furthermore, a ventilation groove for applying a vacuum to make the sheet conform to the forming curved surface is formed in the cavity surface and / or the division surface, and the outer periphery of the vacuum portion at the division surface is surrounded by packing. In addition, the sheet is more securely adhered to the curved surface by vacuuming.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 6 is a sectional view schematically showing a female mold, and FIG. 7 is a sectional view taken along line DD of FIG. FIG. 8 is a plan view showing an outline of the mold 5, and the female mold 5 is provided with a cavity 7 having a molding curved surface along a sheet. A projecting ridge 8 is provided on the divided surface 6 in contact with the cavity 7. The raised portion 8 is usually provided at one location on the side of the molded surface of the cavity where the curvature changes greatly. However, when there are two symmetrical portions where the variation of the curvature is large, it contacts the cavity and reduces the cavity. It may be provided at each of two places located on a line connecting the large portion with the sandwiched portion.

The size of the convex portion may be appropriately determined in consideration of the change in the curvature of the concave curved surface along the sheet of the cavity and the elongation of the sheet to be used. I do. The cross sections of FIGS. 6 and 7 of the embodiment form a gently inclined mountain shape that is continuous with the curved surface of the cavity. A concave portion (not shown) in which the convex ridge 8 can be fitted is provided at a position facing the convex ridge 8 on the divided surface of the male mold.
The shape and size of the concave portion are set so as to sandwich the sheet along the surface of the convex portion.

In the vicinity of the cavities 7 and the ridges 8, ventilation grooves 9 for evacuating are formed. Further, on the outside thereof, an annular rubber (O-ring) 10 is provided so as to surround them.
Installed in the installation groove. FIG. 9 is a perspective view schematically showing a clamp 11 for pushing a sheet into the cavity, and the pushing blade 12 pushes the sheet into the cavity. A support rod 13 protruding at an appropriate position of the clamp 11 is inserted into a guide hole 14 (FIG. 8) of a mold to support the clamp 11 slidably.

At the time of molding, first, a female mold 5 is formed with a sheet.
After covering not only the cavity but also the region beyond the annular rubber, the clamp 11 is advanced and the sheet is pushed into the cavity by the pushing blade 12, and then the sheet is brought into close contact with the cavity by evacuating and the clamp 11 is retracted. . In this case, the sheet is locally extended due to the presence of the ridges 8 to prevent the occurrence of wrinkles on the formed curved surface. Next, the clamp 11 is moved and retracted horizontally, and the female mold 5 is advanced to engage with a male mold (not shown) to close the mold and press the annular rubber to hermetically seal the inside and evacuate. afterwards,
A molded product is obtained by injecting the molten resin according to a conventional method.

[0022]

According to the present invention, there is provided a mold apparatus for simultaneous painting by injection molding which has a curved surface on which a sheet is formed, such as a female mold having a concave curved surface. If it is a mold, a convex ridge corresponding to the magnitude of the curvature of the cavity and the degree of its change is provided on the division surface, that is, a part that is not a product, and the division surface of the male mold is provided at a position facing the convex ridge. Since the concave portion into which the convex portion can be fitted is provided, the sheet is locally extended by the convex portion, so that no wrinkles are generated in the sheet having a formed curved surface.

In addition, a clamping mechanism provided with a pushing blade for forcibly pushing the sheet so that the sheet follows the curved forming surface prior to the evacuation is attached to the mold apparatus. Wrinkles that are easily formed are prevented, and the subsequent evacuation ensures that the sheet conforms to the curved curved surface. In addition, a ventilation groove for applying a vacuum to make the sheet conform to the forming curved surface is formed in the cavity surface and / or in the division surface, and the outer periphery of the vacuum part in the division surface is surrounded by packing. It has excellent operational effects, such as more secure adhesion to the molding surface by evacuation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a product formed by the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 1;

FIG. 5 is a perspective view showing an example of a product formed by a conventional technique.

FIG. 6 is a sectional view schematically showing a female mold.

FIG. 7 is a sectional view taken along line DD of FIG. 6;

FIG. 8 is a plan view schematically showing a mold according to the present invention.

FIG. 9 is a perspective view schematically showing a clamp.

[Explanation of symbols]

 1 Molded product 2 Resin part 3 Seat part 4 Wrinkle 5 Mold 6 Dividing surface 7 Cavity 8 Convex ridge 9 Vent groove 10 O-ring 11 ── Clamp 12 ── Push blade 13 ── Support rod 14 ── Conductor hole

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (5)

(57) [Claims] 1. A painting sheet or a transfer sheet is placed in a mold, and the sheet is brought into close contact with a molding curved surface of the mold by evacuation, and then the molten resin is injected to fuse the sheet to the resin. In a mold apparatus for simultaneous painting by injection molding, a divided surface of a mold having a molding curved surface on which a sheet is to be arranged is provided with a portion having irregularities opposite to the molding curved surface. Molding equipment for simultaneous painting. 2. A female mold in which a molding curved surface on which a sheet is to be formed is a concave curved surface, a raised portion is protruded at a portion of the divided surface in contact with a cavity, and the divided surface of the male mold is formed on the divided surface of the male mold. The mold device for simultaneous injection molding and painting according to claim 1, wherein a concave portion is provided at a position facing the convex portion so that the convex portion can be fitted therein. 3. A mold apparatus for simultaneous injection molding and painting as set forth in claim 2, further comprising a clamp mechanism provided with a pushing blade for causing the sheet to follow the forming curved surface prior to evacuation. 4. The simultaneous painting for injection molding according to claim 2, wherein a ventilation groove for applying a vacuum to make the sheet conform to the forming curved surface is formed in the cavity surface and / or the dividing surface. Mold equipment. 5. The injection molding simultaneous painting apparatus according to claim 4, wherein the outer periphery of the vacuum evacuation section on one of the divided surfaces of the split mold is surrounded by packing.