JPH02223413A - Manufacture of molded product of synthetic resin - Google Patents

Abstract

PURPOSE:To form a synthetic resin molded product provided with a flexible protrusion, by turning over a process where an intermediate molded product provided with a recessed part is molded by sticking a synthetic resin material to the surface of a mold provided with a protrusion and the recessed part of a hollow molded product. CONSTITUTION:Epoxy resin is cast through a casting hole 9b provided into a reinforcing member 9a for curing and a mandrel 9 provided with a recessed part 7 and a secondary embossed pattern 8 comprised by transferring a reverse embossed pattern 3. Then after formation of a thin conductive film 10 on the surface of a mandrel 9 through adhesion, electroforming is performed on the surface and an electroforming mold 13 provided with a protrusion 11 and a tertiary reverse embossing pattern 12 comprised by transferring the secondary embossing pattern 8 is formed. A molded product 1 having a biquadratic embossing pattern 17 is formed by a method wherein, the electroforming mold 13 is peeled off from the mandrel 9, vinyl chloride resin powder 15 is stuck to the surface of the heated electroforming mold 13 and melting, cooling and curing are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a synthetic resin molded article having a convex portion.

[Prior art] Conventionally, synthetic resin molded products with convex portions are manufactured by attaching synthetic resin powder or synthetic resin paste to the surface of an electroforming mold having concave portions and performing slush molding or rotation molding. method is being done. For example, the second
A method for manufacturing a synthetic resin molded product 41 as shown in FIG. 4 by slush molding will be briefly described with reference to FIGS. 13 to 24.

(1) A master model with convex portions 45 is created by pasting a pattern imparting material 44 (cowhide in this case) with a fine original grain pattern 43 shown in FIG. 14 on the surface of a model 42 shown in FIG. 13. form 46.

(2) As shown in FIG. 15, by injecting silicone rubber onto the surface of the master model 46 and curing it, a secondary reverse grain pattern 48 is created by transferring the recesses 47 and the original grain pattern 43. forming an intermediate mold 49 having a first
As shown in FIG. 6, the intermediate mold 49 is peeled off.

(3) As shown in FIG. 17, a reinforcing member 52a made of iron, aluminum, etc. is applied to the intermediate mold 49 with a gap between the surfaces thereof. The injection hole 5 provided in the reinforcing member 52a
By injecting epoxy resin into the gap from 2b and curing it, the convex portion 50 and the secondary reverse grain pattern 48 are formed.
A mandrel 52 having a tertiary grain pattern 51 formed by transferring the same is formed, and as shown in FIG. 18, the mandrel 52 is
Peel off.

(4) As shown in FIG. 19, a thin conductive coating 53 is formed on the surface of the mandrel 52 by spraying paste silver lacquer.

(5) As shown in FIG. 20, by performing electroforming on the surface of the conductive film 53, the recesses 54 and the tertiary grain pattern 5 are formed.
An electroforming mold 56 having a quaternary reverse grain pattern 55 formed by transferring 1 is formed. At this time, the electroformed metal is made of mandrel 5
Electrodeposition is likely to occur at protruding locations such as the top corners of the convex portions 50 of No. 2, while electrodeposition is difficult to occur at recessed locations such as the bottom corners of the convex portions 50. In this case, the bottom corner of the recess 54 is formed thicker, and the opening corner of the recess 54 is formed thinner.

(6) As shown in FIG. 21, the electroforming mold 56 is peeled off from the mandrel 52, and a conductive coating 5 is applied to the electroforming mold 56.
3 has adhered, the conductive film 53 is removed chemically or physically.

(7) As shown in FIG. 22, vinyl chloride resin powder 5 is applied to the surface of the heated electroforming mold 56 with the supporting member 57 attached.
8, and by melting and cooling and hardening the vinyl chloride resin powder as shown in FIG. 23 (slush molding), a tertiary grain pattern 60 is formed by transferring the convex portions 59 and the quaternary reverse grain pattern 55. Synthetic resin molded product 41 comprising
to form.

At this time, since the bottom corner of the recess 54 of the electroforming mold 56 is formed thickly and has a large heat capacity as described above, a large amount of the vinyl chloride resin powder 58 adheres to the bottom corner.

On the other hand, since the opening corners of the recesses 54 of the electroforming mold 56 are formed thinly and have a small heat capacity as described above, only a small amount of the vinyl chloride resin powder 58 adheres thereto.

Therefore, as shown in FIG. 24, in the conventional synthetic resin molded product 41, the top corners of the convex portions 59 are formed thicker, and the bottom corners of the convex portions 59 are formed thinner.

[Problems to be Solved by the Invention] In the conventional method as described above, an electroforming mold 56 having a concave portion 54 is used to manufacture a synthetic resin molded product 41 having five convex portions. Therefore, there was a problem in that it was difficult to supply the vinyl chloride powder 58 to the recess 54.

In addition, the synthetic resin molded product 41 manufactured using the electroforming mold 56 with uneven thickness as described above has a rough feel because the top corner of the convex portion 59 that is most easily touched by the hand is particularly thick. There is a problem in that it tends to become hard and lack elasticity. In particular, recently there has been an increasing demand for softer synthetic resin molded products, but it has been difficult to meet this demand using conventional methods.

An object of the present invention is to provide a novel method for manufacturing synthetic resin molded products that solves the above problems.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a synthetic resin molded product according to claim 1 is provided by attaching a synthetic resin material to the surface of a mold having a convex part. The method consisted of a step of molding an intermediate molded product, and a step of forming a synthetic resin molded product having a convex portion by turning over the recessed portion of the intermediate molded product.

The method for manufacturing a synthetic resin molded product according to claim 2 further includes the steps of forming a mandrel with a recess, forming a conductive film on the surface of the mandrel, and performing electroforming on the surface of the conductive film. a step of manufacturing an electroforming mold having a convex portion, a step of peeling the electroforming mold from the mandrel, and a step of attaching a synthetic resin material to the surface of the electroforming mold to produce an intermediate molded product having four parts. The method consisted of a molding step and a step of forming a synthetic resin molded product having a convex portion by turning over the concave portion of the intermediate molded product.

[Function] According to the method for manufacturing a synthetic resin molded product according to claim 1, since a mold having a convex portion is used, contrary to the conventional method, the synthetic resin material can be easily supplied to the surface of the mold. There is.

According to the method for manufacturing a synthetic resin molded product according to the second aspect, in addition to the above-mentioned effect, even if the electroforming mold has uneven thickness, the top corner of the convex portion of the synthetic resin molded product can be formed thin.

[Example] Hereinafter, regarding an example embodying the present invention, 1st to 1st
This will be explained with reference to FIG. The present embodiment relates to a method of manufacturing a synthetic resin molded product 1 having a convex portion 19 as shown in FIG. 12 by slush molding, and includes the following steps.

(1) As shown in Fig. 1, a model 2 having the same shape as the desired synthetic resin molded product is formed from wood, synthetic resin, plaster, wax, and other various materials, and then as shown in Fig. 2, it is made of cowhide, suede, etc. A master model 6 having convex portions 5 is formed by pasting a transparent pattern imparting material 4 having a reverse grain pattern 3 on the surface of the model 2, which is formed by reversing the uneven relationship of the grain pattern of cloth or the like. .

(2) As shown in FIG. 3, a reinforcing member 9a made of iron, aluminum, etc. is applied to the surface of the master model 6 with a gap left in between. Then, by injecting an epoxy resin or other reaction-curing material into the gap from the injection hole 9b provided in the reinforcing member 9a and curing it, a secondary product is formed by transferring the concave portion 7 and the reverse grain pattern 3. A mandrel 9 having a grain pattern 8 is formed, and the mandrel 9 is peeled off as shown in FIG.

(3) As shown in FIG. 5, a thin conductive film 10 is deposited on the surface of the mandrel 9.

Examples of methods for forming the conductive film 10 include silver mirror reaction, spray application of paste silver lacquer, electroless plating, vapor deposition plating, and the like.

Further, the thickness of the conductive film 10 is preferably 5 to 30 μm, because if it is too thin, sufficient conductivity will not be obtained, and if it is too thick, the fidelity of the secondary grain pattern 8 will be reduced.

(4) As shown in FIG. 6, by performing electroforming on the surface of the conductive coating 10, the protrusions 11 and the secondary grain pattern 8 are formed.
An electroforming mold 13 having a tertiary reverse grain pattern 12 formed by transferring the above is formed.

As this electroforming method, an electroforming method comprising a known general electroforming metal, electroforming bath, and electroforming conditions can be adopted.

In this example, the mandrel 9 and the nickel electrode (as shown in the figure) as the electroformed metal are immersed in an electroforming bath mainly composed of nickel sulfamate, boric acid, and a surfactant for suppressing pinholes. General electroforming was performed by applying a DC voltage between the conductive liquid Jl (10 (cathode) and the nickel electrode (anode)).

During this electroforming, the electroformed metal is formed in the recess 7 of the mandrel 9.
Electrodeposition is likely to occur at protruding locations such as the opening corners of the recess 7, while electrodeposition is difficult to occur at recessed locations such as the bottom corners of the recess 7. Therefore, uneven thickness occurs in the electroforming mold 13, so that the bottom corners of the protrusions 11 are formed thicker, and the top corners of the protrusions 11 are formed thinner.

(5) As shown in FIG. 7, the electroforming mold 13 is peeled off from the mandrel 9, and the conductive liquid 1 (10
If the conductive film 10 is attached, the conductive film 10 is removed chemically or physically. FIG. 8 shows the tertiary reverse grain pattern 12 of the electroforming mold 13 produced as described above.

(6) As shown in FIG. 9, the support member 14 is attached to the electroforming mold 13.
is attached, and vinyl chloride resin powder 15 is adhered to the surface of the heated electroforming mold 13.

At this time, in this embodiment, unlike the conventional electroforming mold 56 having a concave portion 54, an electroforming mold 13 having a convex portion 11 is used.
, the vinyl chloride resin powder 15 can be easily supplied by, for example, a known powder electrostatic method. This effect of facilitating supply is the same when using synthetic resin paste or urethane reaction liquid, which will be described later.

Then, as shown in FIG. 10, by melting and cooling the vinyl chloride resin powder 15 and hardening it (slush molding), a concave portion 16 and a quaternary grain pattern 17 formed by transferring the tertiary reverse grain pattern 12 are formed. An intermediate molded product 18 is then molded.

In this step, since the bottom corner portion of the convex portion 11 of the electroforming mold 13 is formed thickly as described above and has a large heat capacity, a large amount of the vinyl chloride resin powder 15 adheres to the bottom corner portion. On the other hand, since the top corner of the convex part 11 of the electroforming mold 13 is formed thinly and has a small heat capacity, a small amount of vinyl chloride resin powder 15 is added to the top corner of the convex part 11 of the electroforming mold 13.
It only sticks.

Therefore, as shown in FIG. 11, the intermediate molded product 18
In this case, the opening corners of the recess 16 are formed thicker, and the bottom corners of the recess 16 are formed thinner.

(7) As shown in FIGS. 11 and 12, by pushing out the recessed part 16 of the intermediate molded product 18 to the opposite side and turning it over, the recessed part 16 is turned over to form a convex part 19 and the quaternary grain pattern 17. A synthetic resin molded product 1 is formed.

As a result, the bottom corners of the convex portions 19 of the synthetic resin molded product 1 are formed thickly, but the top corners of the convex portions 19, which are most easily touched by the hand, are formed thinly, so the feel is very soft. It becomes highly elastic.

Therefore, according to this embodiment, it is possible to easily meet the recent demand for softening of synthetic resin molded products.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, and may be modified and embodied as desired without departing from the spirit of the invention, for example, as described below.

(1) The method of molding the synthetic resin molded product 1 is not limited to the slush molding described above, and the following molding methods may be used. Further, the synthetic resin material of the synthetic resin molded product 1 is not limited to the vinyl chloride resin powder 15, and the following materials can be exemplified for each of the above molding methods.

■ Slash molding or rotation molding a: Adhere polyethylene resin powder, ethylene vinyl acetate resin powder, and other various synthetic resin powders to an electroforming mold.

b; Attach vinyl chloride resin paste, polypropylene resin paste, and other various synthetic resin pastes to the electroforming mold.

■Urethane coating Molding A urethane reaction solution consisting of polyol and polyisocyanate is applied to the electroforming mold.

If this urethane reaction liquid is used, it can be cured quickly simply by supplying amine gas to cause the urea reaction, so that production efficiency can be further improved. For example, one production cycle takes about 5 minutes when vinyl chloride resin powder is melted and cooled, whereas this time can be shortened to about 1 minute when a urethane reaction liquid is cured.

(2) As the mold according to claim 1, various known molds formed by methods other than electroforming can also be used.

(3) The surface of the mandrel 9 may be provided with various fine uneven patterns other than the secondary grain pattern 8, or may have a mirror surface without a pattern.

(4) The method for forming the mandrel 9 is not limited to the steps of the above embodiments, and can be formed by various known methods.

[Effects of the Invention] Since the method for manufacturing a synthetic resin molded article of the present invention is configured as described above, it has the following effects.

According to the method for manufacturing a synthetic resin molded article according to the first aspect, the synthetic resin material can be easily supplied to the mold.

According to the method for manufacturing a synthetic resin molded article according to the second aspect, in addition to the above-mentioned effects, a synthetic resin molded article having convex portions with a rich soft feel can be easily manufactured.

[Brief explanation of the drawing]

1 to 12 show an example of the method for manufacturing a synthetic resin molded product embodying the present invention, and FIG. 1 is a sectional view of the model, and FIG.
The figure is a cross-sectional view of the master model, Figure 3 is a cross-sectional view when epoxy resin is injected into the master model to form a mandrel, Figure 4 is a cross-sectional view of the mandrel, and Figure 5 is a conductive coating on the mandrel. 6 is a wavefront diagram when an electroforming mold is electroformed on the conductive film,
FIG. 7 is a sectional view of the electroforming mold, FIG. 8 is a partially enlarged perspective view of the electroforming mold, FIG. 9 is a sectional view when vinyl chloride resin powder is attached to the electroforming mold, and FIG. 10 is a sectional view of the electroforming mold. The figure is a cross-sectional view of an intermediate molded product molded from the vinyl chloride resin, FIG. 11 is a cross-sectional view of the intermediate molded product, and FIG. 12 is a cross-sectional view of a synthetic resin molded product. Figures 13 to 24 show a conventional method for manufacturing synthetic resin molded products, with Figure 13 being a cross-sectional view of the model, Figure 14 being a cross-sectional view of the master model, and Figure 15 showing the process of injecting silicone rubber into the master model. Cross-sectional view when an intermediate mold is formed, No. 16
The figure is a sectional view of the intermediate mold, FIG. 17 is a sectional view of the mandrel formed by injecting epoxy resin into the intermediate mold, FIG. 18 is a sectional view of the mandrel, and FIG. 19 is a sectional view of the mandrel. FIG. 20 is a cross-sectional view when a film is formed, and FIG. 21 is a cross-sectional view when an electroforming mold is electroformed on the conductive film.
The figure is a cross-sectional view of the electroforming mold, Figure 22 is a cross-sectional view when vinyl chloride resin powder is attached to the electroforming mold, and Figure 23 is a cross-sectional view when a synthetic resin molded product is molded with the vinyl chloride resin. FIG. 24 is a cross-sectional view of the synthetic resin molded product. DESCRIPTION OF SYMBOLS 1... Synthetic resin molded product, 7... Recessed part, 9... Mandrel, 10... Conductive coating, 11... Convex part,
13... Electroforming mold, 15... Vinyl chloride resin powder as synthetic resin material, 16... Concave portion, 18... Intermediate molded product,
19...Protrusion.

Claims (1)

[Claims] 1. An intermediate molded product (18) having a concave portion (16) is molded by attaching a synthetic resin material (15) to the surface of a mold (13) having a convex portion (11). and forming a synthetic resin molded product (1) having a convex portion (19) by turning over the concave portion (16) of the intermediate molded product (18). 2. Forming a mandrel (9) with a recess (7), and forming a conductive coating (10) on the surface of the mandrel (9).
and electroforming mold (13) provided with convex portions (11) by performing electroforming on the surface of the conductive coating (10).
), peeling off the electroforming mold (13) from the mandrel (9), and attaching a synthetic resin material (15) to the surface of the electroforming mold (13) to form a recess (16). and a step of forming a synthetic resin molded product (1) having a convex portion (19) by turning over the concave portion (16) of the intermediate molded product (18). A method for manufacturing a synthetic resin molded product comprising: