JPH06114861A - Production of urethane elastomer molded product - Google Patents

Abstract

PURPOSE:To produce a urethane elastomer molded product by simply and economically molding an urethane elastomer. CONSTITUTION:A soft urethane foam powder is received in a mold and heated to about 180-200 deg.C to be pressed to obtain a urethane elastomer molded product having a specified shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a urethane elastomer molded article.

[0002]

2. Description of the Related Art For example, as a method for obtaining a urethane elastomer, an elastomer having a density of about 1.0 to 1.2 g / cm ³ is obtained by reacting a highly reactive urethane raw material with injection molding, which is so-called RIM molding method. A method for obtaining a molded product, a method for obtaining a molded product by mixing a crushed product of the urethane elastomer obtained by the RIM molding method with an adhesive and heating and pressing, and further injection molding of a thermoplastic urethane. There is a way.

However, in the first method, not only is it unsuitable for small-quantity production, but there is a risk that the injection equipment and mold structure for injecting and reacting the above-mentioned raw materials are complicated and costly. .

In the second method, not only the process is complicated and there is a problem in productivity, but also the material cost increases due to the use of the adhesive material, so that the production cost tends to increase as a result. In addition, in such a method, it is difficult to color the molded product, and the size of the crushed urethane elastomer product is about 2 to 5 mm, so the surface of the obtained molded product is uneven and characters and patterns are formed. Is difficult to appear sharply.

Furthermore, in the third method, not only the cost of materials used is high, but also the equipment for injection molding is expensive as in the first method.

By the way, in recent years, due to the large amount of use of synthetic resins, the amount of resins discharged as waste has become enormous, and the treatment thereof has become a problem. In particular, recently, the global environment has become a big social problem, and reduction of waste and effective use of resources are required.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems, and provides a method for producing a urethane elastomer molded product, which allows a urethane elastomer to be molded easily and economically. It is what

[0008]

That is, the present invention is
Fill the mold with soft urethane foam powder, about 180 ℃
The present invention relates to a method for producing a urethane elastomer molded article, which comprises obtaining a urethane elastomer molded article having a predetermined shape by heating to ~ 200 ° C and pressing.

[0009]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

According to the present invention, a soft urethane foam pulverized into a powder is filled in a molding die which defines the shape of a molded article,
A urethane elastomer molded product having a predetermined shape is obtained by heating at a predetermined temperature and applying pressure.

As the soft urethane foam used in the present invention, those having a relatively low degree of crosslinking such as soft slab and soft mold urethane are preferable, and the density thereof is about 0.012.
Known ether type and ester type of 0.100 g / cm ³ are used. The soft mold urethane may be molded by either cold cure or hot cure. Further, it is also possible to use the waste material of the flexible urethane foam and a mixture thereof.

The soft urethane foam is pulverized by a known method to obtain fine powder having a size of about 250 μm to 2 mm. As a result, in the molding step to be described later, the raw material urethane powder can be filled evenly in the mold with high density. If the size of the soft urethane foam powder is smaller than 250 μm, the crushing process is time-consuming, and if it is larger than 2 mm, the surface of the obtained molded product is uneven.

The soft urethane foam powder thus obtained is filled, if desired, with an appropriate additive such as a known stabilizer into a mold having a predetermined shape, heated and pressed. As a result, the soft urethane foam powder is melted and adhered to each other to form an integral elastomeric molded article. In this molding step, the molding temperature of the soft urethane foam powder is about 180 ° C to 20 ° C.
At 0 ° C, preferably 180 ° C to 190 ° C.

When the pressing temperature is lower than 180 ° C.,
At the time of molding, the flexible urethane foam may not be sufficiently melted and may cause defective molding. When the temperature exceeds 200 ° C., the flexible urethane foam is thermally deteriorated.

The pressing pressure and pressing time are appropriately determined according to the type of the flexible urethane foam used, the shape of the molded product, the required physical properties, and the like. In this example, the pressing pressure is 250 to 300 kg / c.
m ² , pressing time is 5 to 6 minutes.

Further, the soft urethane foam powder is 2
It is also preferable to be composed of one or more kinds of appropriately colored soft urethane foam powder. By appropriately placing and heating the colored powder in a mold,
A urethane elastomer molded product colored in a marble pattern or two-tone color can be obtained.

Further, in order to improve the strength and modulus of the urethane elastomer, a reinforcing material such as glass chop is mixed with the soft urethane foam powder, or a sheet material made of the glass chop is previously placed in a mold to soft urethane. It is also possible to heat and press with the foam powder.

The resulting urethane elastomer molded article is
The surface is extremely smooth, and not only the letters and textures formed on the mold are clearly formed, but the shape of the mold is faithful even if it has a three-dimensional shape such as a concave surface. Will be reproduced.

[0019]

As shown and described above, according to the method of the present invention, the finely divided soft urethane foam is filled in the mold and heated and pressed.
Not only is the surface smooth and beautiful, but the shape and surface pattern of the mold are also sharply represented. Also, since the molded product is integrally molded by melting the flexible urethane foam itself, there is no need to mix adhesives, etc., and it is possible to obtain a urethane elastomer molded product very simply and economically in terms of process and cost. You can Furthermore, since urethane materials having different densities can be mixed and used, waste can be recycled and resources can be effectively used.

Claims (2)

[Claims] 1. A urethane elastomer molded article obtained by filling a soft urethane foam powder in a mold, heating it to about 180 ° C. to 200 ° C. and pressing it to obtain a urethane elastomer molded article having a predetermined shape. Production method. 2. The method for producing a urethane elastomer molded article according to claim 1, wherein the soft urethane foam powder is composed of two or more kinds having different colors.