JPS6015455B2 - Method for manufacturing plastisol skin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming thin-walled hollow skins from vinyl chloride plastisol by slush molding.

Many slush molding methods have been proposed for the skin of automobile dashboard covers or instrument panel pads, among which a representative example is the so-called gas slush method.

This method involves filling and then emptying a mold with plastisol to create a coating on the inner surface of the mold, injecting a pressure stream of hot gas directly onto the outer surface of the mold to gel this coating, and then gelling the mold. The method consists of the steps of forming a sol coat on top of the coated coating and injecting a pressure stream of gas onto the inner and outer surfaces of the mold to obtain a skin of a constant thickness that is fused and integrated. However, this method uses a long conveyor belt and a large number of molds at the same time, so although it is suitable for obtaining a skin of a specific color, it is not suitable for obtaining skin of different colors in a short time. In addition, as another method, as disclosed in Japanese Patent Publication No. 10-10-1983, pipes for flowing heating oil and cooling oil are installed on the surface of the mold, and the mold is filled with sol. Afterwards, the mold is emptied to form a film, heated oil is poured into the mold to gel it, and this process is then repeated to create two layers of gel film on the surface of the mold.After that, cooling oil is poured in and the epidermis is removed. There is a way.

A major feature of this method is that the amount of gel deposited can be controlled by controlling the temperature of the oil in order to reduce the thickness of unnecessary parts of the skin. However, this method does not pose any problems when manufacturing a large number of skins of a specific color in succession, but when manufacturing products of various colors, such as automobile parts, quickly, the color sol of each color is used. It is necessary to have a storage tank, a surplus sol recovery tank, and a defoaming device, respectively, which has the disadvantage of increasing equipment costs and equipment installation space.

Moreover, these methods require coating the inner surface of the mold with at least two coats of the same color sol to create a skin of a certain thickness, which makes it difficult to coat the skin of products that are used at high temperatures and under direct sunlight, such as dashboard covers. requires the addition of a large amount of stabilizer to prevent discoloration, so an increase in sol cost is unavoidable. Furthermore, when creating a skin with relatively high hardness, the amount of plasticizer is reduced, but the increase in sol viscosity inevitably causes molding defects such as pinholes. The present invention has been made in order to improve the conventional problems as described above.The purpose of the present invention is to easily produce epidermis of different colors in a short time, and to use stabilizers and colorants. The goal is to manufacture a skin with less pinholes and other defects by adding a small amount of plastic.The first step is to spray a colored plastic sol onto the inner surface of the open mold to create a uniform thickness. After forming a thin film, a gel layer is formed by heating, and in the second step, plastisol without coloring or with a smaller amount of colorants, stabilizers, etc. added than the colored plastisol is applied to the inner surface of the colored gel layer. After filling the mold, heat is applied as necessary to form a gel layer of a predetermined thickness.Then, in the third step, excess ungelled plastisol is discharged and both gel layers attached to the inner surface of the opened mold are completely removed. The hollow outer skin is heated until it is melted and integrated, and the fourth step is to remove the hollow skin from the mold.

Hereinafter, the method of the present invention will be explained in more detail with reference to the accompanying drawings.

FIG. 1 shows an outline of a slush molding apparatus for carrying out the manufacturing method of the present invention. In the figure, 1 is a mold apparatus, and an open mold 2 is set in a rotating box 3.

This rotating box 3 can be rotated in the direction of the arrow in the figure, and the sol filled in the mold can be discharged by this rotation. Further, the temperature of the mold 2 can be controlled, and a pipe (not shown) is provided in the rotating box in order to control the temperature to a desired temperature. On the other hand, reference numeral 4 denotes a sol storage tank device attached to the mold device 1, which includes an upper sol storage tank 9 and a lower surplus sol collection tank 6. A collection tank 6 is fixed, and the sol accumulated in the collection tank 6 is guided by a pipe 7 to a sol storage tank 9 via a defoaming device 8.

The sol storage tank 9 stores uncolored plastisol, which is one of the components of the present invention, or plastisol in which the amount of colorant and stabilizer added is very small. Furthermore, in the figure, numeral 10 is a spray gun device corresponding to the sol storage tank 9, and a coloring agent, which is another component, stored in the storage tank 11. It is equipped with a spray gun 12 for spraying and adhering lastisol to the mold.

Next, a case in which the method for producing a skin of the present invention is carried out using the above-mentioned slush molding apparatus will be explained with reference to FIGS. 2 to 6.

First, in the first step of the method of the present invention, the colored plastisol stored in the storage tank 11 of the spray gun device 10 is sprayed onto the inner surface of the mold 2 placed in the rotary box 3 using the spray gun 12 to form a coating of 0.3 ribs. The mold 2 is heated at 150° C. for 3 hours to gel, thereby forming a film 13 of about 100 ml.

(See FIGS. 2 and 3) Of course, in this case, it is not limited to spraying sol of the same color onto the surface of the mold, but may also locally spray sol of a different color.

Therefore, more than one spray gun can be used. The formulation (parts by weight) of the colored plastic sol used here includes Zeon 202.4 Soto, DOA. 65 parts, liquid Cd, 2 parts of stabilizer, 2 parts of calcium carbonate, and 5 parts of colored pigment.

Next, as a second step, the uncolored plastisol 14 stored in the sol storage tank 9 is filled into the mold 2 having the colored gel layer, the mold 2 is heated to 15,000, and the gel layer on the approximately 0.5 side is removed from the mold 2. Create within.

(See FIG. 4) After completing the preliminary work, in the third step, the mold 2 is rotated by 180 degrees to discharge the excess uncolored plastic.

(See FIG. 5) At this time, a colored gel layer and an uncolored gel layer remain laminated on the inner surface of the mold 2. Next, this mold is heated to about 250° C. until both gel layers are completely melted and integrated. Finally, in the fourth step, the mold 2 is cooled to about 60q0, and the obtained skin 15 is taken out from the mold 2, and the work is completed. The formulation (parts by weight) of the uncolored plastisol used here is Zeon 135J. 100 copies, DOP. 60 copies, DOA. 5
Department, Fellow 5163.3 Department, Scissor EPO. There are 4 parts.

However, the present invention is not limited to such uncolored plastisols, and plastisols containing small amounts of colorants and stabilizers or foamable sols can be used at any time. Thus, the epidermis obtained through the above steps has a colored layer of about 0.3 side and an uncolored layer of about 0.5 side, and is more expensive than a case where the entire thickness is made up of colored layers. The amount of colorants and stabilizers used will be halved.

In addition, even if uncolored plastisol has a fairly high viscosity, a gel layer of colored sol is already formed on the inner surface of the mold during the second stage of filling the mold, so the method of the present invention can prevent pinholes, etc. in the recesses on the mold surface. It is possible to form a highly hard epidermis with no breakouts.

Furthermore, the most significant effect of the present invention is that the colored sol applied in the first step by the spray method does not require collection of the sol, unlike in the case of slush, so the storage tank for the colored sol has a small capacity. It is also possible to manufacture tanks with
Additionally, there is no need for surplus sol recovery tanks or defoaming devices for each color. As described above, the method of the present invention has much better effects than the conventional method, is highly practical, is industrially advantageous, and is expected to be implemented in terms of economy and quality. This is a method to

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a slush molding apparatus used to implement the manufacturing method of the present invention, and FIGS. 2 to 6 are explanatory views showing the manufacturing steps of the method of the present invention, respectively. 2...Mold, 3...Rotating box, 13...
...First step plastisol coating, 14...
2nd step plastisol, 15... Epidermis. Many diagrams, many Z diagrams, many Ta diagrams, many J diagrams, many J diagrams

Claims (1)

[Scope of Claims] 1. A first step of spraying colored plastisol onto the inner surface of the mold to form a thin film of uniform thickness, and then gelling the thin film to form a thin gel layer; After filling the inner surface of the gel layer with plastisol that is uncolored or has a lower amount of coloring agent, stabilizer, etc. than the plastisol used in the first step, a second step is slush molding to form a gel layer of a predetermined thickness. Thereafter, a third step is to discharge excess ungelled plastisol from the mold and heat the mold until both gel layers adhering to the inner surface of the mold are completely melted and integrated, and then the skin obtained in the previous step is heated. A method for producing a plastisol skin, comprising the steps of a fourth step of removing it from a mold. 2. The method for producing a plastisol skin according to claim 1, wherein a mold is set in a rotating box, and excess ungelled plastisol in the mold is discharged by rotating the rotating box.