JPH08127030A - Cast masking molding method for thermorlastic resin product - Google Patents

Abstract

PURPOSE: To manufacture easily a resin product of a beautiful rubber elasticity having a number of colors and optional shapes at low cost. CONSTITUTION: A molding method comprises a process of placing a molding sheet 1 provided with a molding tool 2 and a mask 3 consisting of a plurality of mask constituting pieces 3a, 3b, 3c... to be fitted into the molding tool 2 and separable one another on the upper face of a heated base plate 4 and a process of casting a thermoplastic resin liquid 6a of a desired color into a section from which optional mask constituting pieces in the mask 3 are removed, curing the resin and then casting a thermoplastic resin liquid 6b of the same color as above or different color into another section from which other mask constituting pieces are removed. Also the method comprises a process of embedding molding tools 2 of the molding sheet 1 successively by repeating the required number of curing processes and also a process of further heating a resin molded body 6 on the base plate 4 separated from the molding sheet 1, gelling, and then cooling the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting masking method for molding thermoplastic resin products.

[Prior art]

[0002] Conventionally, thermoplastic resin products, for example, key chains having rubber elasticity, accessories such as broaches,
Fancy accessories, toys, etc. were molded by blow molding or injection molding.

[0003]

However, the above-mentioned blow molding and injection molding are not suitable for molding such small articles as described above. This is because the molding die has a large size for the product, which inevitably increases the cost.

The present invention has been made in view of the above-mentioned problems of the above-mentioned prior art, and uses a molding sheet and a mask on which a molding die of an arbitrary shape is formed, and heats the thermoplastic resin liquid while heating. A method of casting masking of thermoplastic resin products, which enables a resin product having a semi-three-dimensional rubber elasticity with a rounded upper surface to be molded in a short time and at low cost by sequentially pouring it into a molding die of a molding sheet. The purpose is to provide.

[0005]

In order to achieve the above object, the method of casting masking of a thermoplastic resin product of the present invention comprises a mold on the upper surface of a heated base plate, and a mold which is fitted into the mold and is separated. A step of placing a molding sheet having a mask composed of a plurality of possible mask constituent pieces, and pouring a thermoplastic resin liquid of a desired color into a portion of the mask from which any mask constituent piece is removed, and solidifying the resin. After that, the step of pouring a thermoplastic resin liquid of the same color or a different color from the above into the portion where the other mask component pieces are removed and solidifying the same is repeated a necessary number of times, and a step of sequentially filling the molding die of the molding sheet The method further comprises the step of further heating the resin molded body on the base plate separated from the molded sheet, gelling the resin molded body, and then cooling it.

[0006]

A molding sheet and a mask composed of a plurality of mask constituent pieces to be fitted into the molding die are provided, and a thermoplastic resin liquid is sequentially poured into a portion from which each mask constituent piece is removed, and by heat molding, Multicolored and beautiful products with rubber elasticity can be easily molded at low cost.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a manufacturing process of the present invention, FIG. 2 is an enlarged sectional view after product molding, and FIG. 3 is a front view of a product manufactured by the method of the present invention.

In FIG. 1, reference numeral 1 is a forming sheet having a plate thickness of about 1 to 3 mm, and a forming die 2 having an arbitrary shape is formed inside thereof. The molding die 2 is preferably a punching die 2a as shown in the drawing, but it is also possible to use a molding recess (not shown).

Reference numeral 3 denotes a mask having the same shape and size as the molding die 2, and a plurality of mask constituent pieces 3a, 3 which are separable from each other.
It is configured by combining b, 3c ...

As the above-mentioned molded sheet 1, a silicone rubber sheet is excellent in its characteristic, that is, heat resistance, easy to process,
It is optimal in terms of good releasability and low cost. However, other sheet materials such as a heat-resistant polyimide resin sheet or a metal plate such as stainless steel can be used.

Then, the molding sheet 1 is placed on the base plate 4 with the mask 3 fitted in the mold 2 and the base plate 4 is placed on the hot plate 5, and 150 to 18
Heat at a temperature of 0 ° C. for about 1 minute.

An aluminum plate is suitable for the base plate 4, but an iron plate, a stainless plate, or another metal plate may be used. As the hot plate 5, any one such as an electric heater or a gas heater can be selected as long as the heating temperature can be kept constant.

In the next step, the thermoplastic resin liquid 6a is poured into the molding die 2 of the molding sheet 1. This step will be described in detail below. First, a part of the mask 3, that is, the mask component piece 3a is removed from the molded sheet 1 on the base plate 4 heated as described above, and the thermoplastic resin liquid 6a of a desired color is poured into the part.

The resin liquid 6a poured in this way
Is the inner edge of the molding die 2 and other mask component pieces 3b, 3c ...
・ Stops by contacting with the outer edge of, and further rounds up due to the surface tension and solidifies with a thickness of about 3 to 5 mm.

Next, the remaining mask constituent pieces 3b are removed from the molded sheet 1, a thermoplastic resin liquid 6b of a different color is poured into the portion, and after solidifying as described above, the remaining mask constituent pieces 3c. Is removed, and the thermoplastic resin liquid 6c of another color is further poured therein to solidify.

Thereafter, the same method is repeated as many times as necessary to inject the thermoplastic resin liquid one after another to solidify it,
When the entire molding die 2 is filled, the resin molding 6 shown in FIG.
Heat at a temperature of 00 to 300 ° C. for about 2 to 5 minutes to cause gelation. Then, after gelling, the product is cooled by water cooling or natural cooling and peeled off from the base plate 4, and a beautiful product A having rubber elasticity and exhibiting a plurality of colors as shown in FIG. 3 is completed.

This product A can be used as an accessory such as a key chain, a brooch, a barretto, a headband, a fancy accessory, or a toy, depending on the shape of the mold 2 of the molded sheet 1.

From the molded sheet 1 to the mask component pieces 3a,
When removing 3b, 3c ..., the needle 7 such as a thumbtack is used in the illustrated example, but other tools or only the hand can be used.

Thermoplastic resin liquid 6 which is a raw material of the product A
As the material of a, 6b, 6c ..., Vinyl polymer or a vinyl polymer or a material can be used as long as it is a material that can be molded into a rounded semi-solid rubber elastic body as shown in FIG. The type of nylon or the like does not matter, but soft vinyl chloride resin is particularly suitable. As shown in FIG. 1, this is put in a tube-shaped container 8 and poured into a molding die 2 of a molding sheet 1 by pouring out from a nozzle 8a portion at the tip.

[0020]

Since the present invention is constructed as described above, it has the following effects. (1) A beautiful resin product having a large number of colors and arbitrary shapes can be easily manufactured at low cost. (2) Since it is a resin product made of a semi-solid rubber elastic material whose surface shape is generally rounded, it has a very high commercial value when used for various small items such as accessories, fancy small items and toys. Is finished. (3) By using a silicone rubber molded sheet having excellent releasability and using a mask, the productivity is extremely improved and the yield is good. (4) Material cost is lower than that of the conventional technology.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of the present invention.

FIG. 2 is an enlarged cross-sectional view after product molding.

FIG. 3 is a front view of a product manufactured by the method of the present invention.

[Explanation of symbols]

 1 molding sheet 2 molding die 3 masks 3a, 3b, 3c mask constituent pieces 4 base plate 5 hot plate

Claims (1)

[Claims] 1. A step of placing a molding sheet having a molding die and a mask composed of a plurality of separable mask constituent pieces, which is fitted into the molding die, on a heated upper surface of the base plate; A thermoplastic resin liquid of the desired color is poured into the part where the arbitrary mask component is removed, and the resin is solidified, and then a thermoplastic resin liquid of the same color or different color is poured into the part where the other mask component is removed. , By repeating the step of solidifying a required number of times, the step of sequentially filling the molding die of the molding sheet, and further heating the resin molding on the base plate separated from the molding sheet, and after gelling, A method of casting masking a thermoplastic resin product, which comprises a step of cooling.