JPS62128716A - Manufacture of urethane foam molding having surface skin - Google Patents

Abstract

PURPOSE:To unify manufacturing process and manufacture an urethane foam molding having a surface skin with a comparatively inexpensive equipment by a method wherein the powder of thermoplastic resin is coated on the inner surface of a mold for molding, thereafter, the powder is heated to melt and form the coated film of the resin, subsequently, foaming is performed by pouring the stock solution of urethane. CONSTITUTION:An uniform resin film is formed in the mold for molding urethane by employing the powder of thermoplastic resin. Thermoplastic resin powder is preferably to be the resin powder having the softening point of 200 deg.C or less as the material of a sheet for surface skin. The formation of a thermoplastic resin coated film is achieved by heating the mold to a temperature in which the powder of resin is melted and fluidized after adhered to the inside of the mold, however, the outer surface of the mold or the surface, on which the formation of the coated film is not necessitated, is masked by nylon or the like to prevent the adhesion of the resin powder. Subsequently, the stock solution of urethane is poured into the mold, formed with said resin coated film, to foam and mold it. The stock solution, mixed with toluene diisocyanate, various kinds of polymers and catalyst properly, may be used as the stock solution of urethane.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a urethane molded product having a skin, which is improved so as to form a skin.

(Prior Art) Urethane molded products having a skin are used in large quantities as small molded interior fittings in automobiles, such as headrests, armrests, and the like.

Conventionally, such urethane molded products have been manufactured by first molding a skin sheet, setting the sheet in a urethane mold, and then injecting a urethane stock solution to perform foam molding.

However, the above method requires two separate processes such as molding the skin sheet and foam molding of the urethane, and also requires the troublesome work of inserting and setting the skin sheet into the urethane mold. In addition, the skin sheet is usually formed by methods such as blow molding, slush molding, and rotation molding, but the molding equipment used in these molding methods is generally expensive, and the
$$ II! 1. Is the post to be erased Taguchi? - H1 titer b I/1゜ is not economical as a manufacturing method for small-sized molded internal parts (objective of the invention) The present invention was made in view of the above circumstances, and its purpose is to unify the process. The purpose of the present invention is to provide a method for manufacturing urethane molded products using relatively inexpensive equipment.

Therefore, the object of the present invention is to apply a thermoplastic resin powder to the inner surface of a molding die, heat and melt it to form a resin coating, and then inject a urethane stock solution to form a foam. This can be easily achieved by a method for manufacturing urethane molded products having a characteristic skin.

(Structure of the invention) The present invention will be explained in detail below.

In the present invention, first, a uniform resin coating is formed in a urethane mold using thermoplastic resin powder.

As the thermoplastic resin powder, any of the powders of various resins conventionally known as sheet materials for skins can be used, but resin powders having a softening point of 200° or less are preferable. in particular,
Plasticized polyvinyl chloride, low-density polyethylene, various copolymers or modified products of polyethylene (e.g., ethylene-vinyl acetate copolymer, ethylene-acrylic acid ethyl ester copolymer, ionomer, etc.) that have low rigidity and are soft. A resin powder having a temperature of 200°C or less is desirable.

The particle size of the powder is mostly 200% (more than 70-80%).
It is preferable that the particle size is within the range of ~100 meshes, and there is no particular problem even if particles with a particle size of slightly more than 200 meshes are included. Such a powdered resin can be easily obtained by a mechanical grinding method or a freeze grinding method.

The formation of a thermoplastic resin coating is achieved by allowing the resin powder to adhere to the interior of the mold and then heating it to a temperature at which the powder melts and flows. Areas that do not require resin powder are masked with nylon, Teflon, epoxy resin, melamine resin, etc. to prevent resin powder from adhering to them.

The adhesion resistance of the resin powder is desirably carried out by a fluidized dipping method or an electrostatic coating method using a mold coated with a template in advance and heated to an appropriate temperature, for example, 100 to 150°C.

The fluidized dipping method is a method in which resin powder is suspended and fluidized in a predetermined flow tank, and the mold is immersed in it to prevent the powder from adhering to it. This is a method in which the mold is suspended and a high voltage is applied to prevent powder from adhering.
Both methods are relatively simple and have uniform results with inexpensive equipment.
Can withstand wear. The mold for molding urethane is not particularly limited, but a mold made of a material such as aluminum casting is usually used.

The resin powder adhered to the inner surface of the mold has a melting and flowing temperature, for example, 180 to 250"c1 for plasticized polyvinyl chloride.
200 to 25 for heavy density polyethylene or its copolymer
After being heated to 0°C for 5 to 20 minutes, it is cooled, and then, in the present invention, a urethane stock solution is injected into the mold on which the resin coating has been formed according to a known method, and foam molding is performed. However, as the urethane stock solution, a stock solution obtained by appropriately mixing toluene diisocyanate, various polyols, and a catalyst is typically used.

FIG. 1 is a partially cutaway perspective view of a molded article formed from a mold according to the method of the present invention.

In the figure, (1) is the headrest of a car seat, and the skin part (1) of the headrest (1) is formed by powder melting.
Both 2) and urethane foam (3) are comparable to conventional products.

(Effects of the Invention) According to the present invention explained above, a urethane molded product having a skin can be manufactured in a simplified process and with inexpensive equipment, and therefore, the economical effect of the method of the present invention is large. be.

[Brief explanation of drawings]

Figure 1 is a perspective view of a car seat, Figure 2 is a perspective view of a car seat, and Figure 2 is a perspective view of a car seat.
．． e+ is a partially broken perspective view. In the figure, (1) is the headrest, (2) is the epidermis, and (3)
is a urethane foam.

Claims (3)

[Claims] (1) Urethane molding with a skin characterized by applying thermoplastic resin powder to the inner surface of a molding die, heating and melting it to form a resin coating, and then injecting urethane stock solution and foaming it. Product manufacturing method. (2) The manufacturing method according to claim 1, wherein most of the thermoplastic resin has a particle size of 200 to 100 mesh. (3) The manufacturing method according to claim 1 or 2, wherein the thermoplastic resin powder is applied by a fluidized dipping method or an electrostatic coating method.