JPS61159429A - Repair of cellular urethane rim molding - Google Patents

Abstract

PURPOSE:To enhance adhesion between a repaired surface and a repairing material and to prevent the heat distortion of the repaired place in repairing faults of a reaction injection-molded cellular urethane molding, by using a material having a composition which is the same as that of the material of the molding except the absence of a blowing agent. CONSTITUTION:The repaired surface 1' of a fault 2 of a cellular urethane reac tion injection molding 1 is degreased by washing with white gasoline, trichloroethane or the like. Into this fault, a repairing material 3 of a composi tion which is the same as that of the material of molding 1 except the absence of a blowing agent is poured and cured. This repaired surface is finished by grinding and painting. Said degreasing can also be performed by heating the repaired surface 11' of a fault 12 of a molding 11 at about 180-250 deg.C by means of a heating means having a sharp tip, such as a soldering iron. It is also pos sible that this repair is performed by heating the repaired surface 21' of a fault 22 in a molding 21, degreasing it, forming an undercut portion 24 and pouring a repairing material 23 into it.

Description

[Detailed description of the invention] Industrial application field This invention is directed to reaction injection molding (hereinafter simply referred to as RIM molding).
The present invention relates to a method for repairing foamed urethane molded products, such as automobile steering wheels and air spoilers.

Conventional RIMW technology involves mixing low-molecular stock solutions with a size of 2m, injecting the mixture into a closed mold, and causing a reaction within the mold to form a polymer, but voids are created during the reaction. Easy to occur, especially foamed RI
In the case of M molding, voids tend to become larger.

It is necessary to repair defects such as voids after molding, and as a conventional repair method for urethane foam RIM molded products, for example, as shown in Fig. 9 and Fig. 1θ, urethane foam RIM molded products The repaired surfaces 32' of defective areas 32 of 31 were degreased with white gasoline, commercially available urethane putty 33 was injected and cured, and the repaired surfaces were polished flat and finished by painting as necessary. In this conventional repair method for a foamed urethane RIM molded product, urethane paste made of a material different from that of the molded product was used as a repair material, so the adhesion between the molded product 31 and the urethane patch repair material 33 was poor. In addition, if a molded product is used because the hardness and coefficient of thermal expansion are different between the two, the repair material 33 will be different from the molded product 31.
There was a drawback that the repaired portion peeled off from the repaired surface 32', and the repaired portion was deformed due to expansion and contraction due to heat. In order to overcome this problem, it is possible to use the same material as the molded product as a repair material, but since the repair work is done outside the mold at normal temperature and pressure, in other words, it is difficult to mold the molded product. Since the repair material is cured under different conditions, no skin layer is formed in the repaired area, and the physical properties such as hardness and coefficient of thermal expansion are different from those of the molded product.

Problems to be Solved by the Invention The present invention solves these drawbacks of the conventional repair method for foamed urethane RIM molded products, improves the adhesion between the repaired surface of the molded product and the repair material, and improves the adhesiveness of the repaired part. The purpose of this is to prevent the molded product from peeling off from the repaired surface, and to prevent the repaired part of the molded product from deforming due to heat.

Means for Solving the Problems The method of repairing a foamed urethane RIM molded product of the present invention is to degrease the defective point F9T of the molded product, and repair the defect using a material with a composition excluding the foaming agent from the material composition of the molded product. This is a method of repairing the area by injecting it into the area.

Next, a method for repairing a foamed urethane RIM molded product according to the present invention will be described with reference to examples.

Example 1 As shown in FIGS. 1 and 2, the repaired surface 1' of the defective point PIr2 in the foamed urethane RIM molded product 1 was cleaned and degreased with white gasoline, trichloroethane, etc., and then the molded product 1 was cleaned and degreased with white gasoline or trichloroethane.
A repair material 3 having a composition excluding the foaming agent from the material composition of is injected into the defective location 2, hardened, and the repaired surface is polished,
Paint and finish.

In this Example 1, the repair material becomes a cured product with physical properties almost similar to those of the skin layer of the molded product, and the adhesion to the molded product is considerably improved, preventing the repair material 3 from peeling off, and M deformation of the repaired part. can be prevented.

implementation? lJ2 As shown in Figures 3 to 5, urethane foam RI
The repaired surface 11' of the defective part 12 in the M molded product 11 is degreased by heat treatment at about 180 DEG C. to 250 DEG C. with a heating member (not shown) having a sharp tip, such as a soldering iron. Through this heat treatment, deposits such as fat are removed from the repaired surface 11' of the molded article 11 by thermal decomposition, evaporation, bath decomposition, and the like.

A repair material 1 having a composition excluding the foaming agent from the material composition of the molded product 11 is applied to the defective location 12 of the molded product 11 expanded by heat treatment.
After injecting and curing 3, repair material 1 for molded product 11
The surface of 30 and the surface of molded product 11 near it are polished and finished by painting.

The method for repairing the foamed urethane RIM molded product of Example 2 was to completely degrease it by heat treatment, and to perform the repair work at room temperature and pressure using a repair material that excluded the foaming agent from the material composition of the molded product. Therefore, the reaction curing conditions are different from RIM molding, but the repair material becomes a cured product with physical properties that are almost similar to the skin layer of the molded product.
The adhesion between the expanded repair surface 11'' and the repair material 13 is significantly improved, and it is possible to prevent the repair material 13 from peeling off and to prevent deformation of the repaired area due to expansion and contraction due to heat. It is possible to make the repair material and its outline on the surface of the product less noticeable.

Example 3 As shown in FIGS. 6 to 8, urethane foam RI
Repair surface 21' of defect Fj'r22 in M molded product 21
is degreased by heat treatment, an undercut portion 24 is formed, and a repair portion 3 similar to that in Example 1 is injected and cured.
Polish the surface of 1 and finish by painting.

By forming an undercut portion and injecting the repair material 23 as in the method for repairing a foamed urethane RIM molded product in Example 3, even if the repair material 23 is peeled off from the molded product 21, the repair material 23 can still be molded. It is possible to prevent the product from floating or falling off from the product 21.

Effects of the Invention The method for repairing a foamed urethane RIM molded product of the present invention involves degreasing the defective Ffr of the molded product, and injecting a material with a composition excluding the foaming agent from the material composition of the molded product into the defective location as a repair material. This method can significantly improve the adhesion between the repaired surface of the molded product and the repair material, prevent the repair material from peeling off from the repaired surface of the molded product, and improve the quality of the molded product. It is possible to prevent the sleeve repair station from being deformed by heat.

[Brief explanation of the drawing]

FIGS. 1 to 2 are enlarged cross-sectional views of the process order of one embodiment of the present invention, and FIGS. 3 to 5 are process steps of the second embodiment of the present invention.
FIGS. 6 to 8 are enlarged sectional views of the process order of the third embodiment of the present invention, and FIGS. 9 and 10 are enlarged sectional views of the conventional process order. 1 is a foamed urethane RIM molded product, 2 is a defective area, and 3 is a repair material.

Claims (1)

[Claims] 1. A defective part of a foamed urethane RIM molded product is degreased, and a material having a composition excluding a foaming agent from the material composition of the molded product is injected into the defective part as a repair material to repair it. A method for repairing foamed urethane RIM molded products. 2. The method for repairing a foamed urethane RIM molded product according to claim 1, wherein the degreasing is performed by heat-treating the defective location. 3. The method for repairing a foamed urethane RIM molded product according to claim 2, wherein the heat treatment forms an undercut portion at the defective location.