JPS5931353B2 - Manufacturing method of cushion material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a cushioning material having a texture of partially different hardness.

Polyurethane foam is widely used in various fields as a cushioning material for seats, chairs, sofas, bedding, etc. of automobiles, vehicles, aircraft, etc.

However, in certain fields of use, demands for cushioning functions have become more diverse, and cushioning materials with textures of partially different hardness have been required. For example, cushioning materials for automobile seats need to have a sufficient cushioning effect mainly in the center of the seat to absorb vibrations in the vertical direction, but the edges on both sides of the seat must be able to prevent lateral vibration. It is desirable to have appropriate hardness. In order to meet such demands, cushioning materials have conventionally been constructed by combining different materials with different densities, for example by inserting slabs, marbles, palm locks, etc. into polyurethane foam. There were disadvantages in that positioning of the material was complicated and misalignment occurred during foaming of polyurethane.

On the other hand, as a method to improve the disadvantages of the conventional method while maintaining the characteristics of polyurethane foam, specific parts of the polyurethane foam are processed so that they can be more easily impregnated with a polyurethane foaming solution than other parts, and gold The foaming stock solution is injected into the mold and then foamed, so that the foaming stock solution is impregnated deeper than the surface of the processed part compared to other parts, thereby forming a specific part that is integrally molded with the foam. A method of manufacturing a cushioning material with increased hardness has been proposed (Japanese Patent Laid-Open No. 55-206).

However, in this method, even if closed-cell polyurethane foam is used as the pre-processed polyurethane foam,
Not only the holes and notches, but also the flat areas where these are not drilled are impregnated with the foaming solution to some extent, so after foaming, these impregnated areas also become hard, resulting in loss of cushioning properties and texture. Impregnation of the foaming solution into the holes, cuts, etc. is not necessarily sufficient and it is difficult to obtain the desired hardness. On the other hand, when using closed-cell foam made breathable by crushing or a slab obtained by slicing a block of breathable foam into a predetermined thickness as the pre-processed polyurethane foam,
The impregnation of the foaming stock solution in the surface portion (flat portion) where holes, cuts, etc. are not made further increases, making it impossible to obtain the desired soft texture. The present invention was made in order to eliminate the various drawbacks of the conventional methods as described above, and the surface of a polyurethane foam layered body of a predetermined shape is heat-treated to form a non-impregnable coating, and a predetermined portion of the layered body is coated with a non-impregnable coating. Cutting the non-impregnated film to form a recess impregnated with a polyurethane foaming solution, and then inserting the processed layered body into a mold,
This method further comprises foaming a polyurethane foaming stock solution for producing a cushion material having a texture of partially different hardness. Next, the method of the present invention will be explained in detail with reference to the drawings.

That is, as shown in Figure 1. A urethane foam layered body 1 is prepared. This layered material 1 may be of closed-cell type or of open-celled/clustered type, but in the case of closed-cell type, it is desirable to make it open-celled by crushing. Therefore, slabs obtained by slicing open-cell polyurethane foam blocks are usually used. Moreover, this layered body 1 can be arbitrarily used as either a flexible polyurethane foam or a semi-rigid polyurethane foam depending on the purpose. Furthermore, to obtain open-celled polyurethane foams, cold cure types are usually used. Next, the surface of this polyurethane foam layered body 1 is heat-treated using a heating plate or other heating device to form a non-impregnable coating 2 on the surface as shown in FIG. Furthermore, as shown in FIGS. 3 and 4, predetermined portions of the polyurethane foam layered body 1 on which the non-impregnable coating 2 is formed, that is, portions to be imparted with desired hardness (for example,
The non-impregnable coating 2 is partially cut out at the curved portion 3 in FIG. 4 to form a recess 4 impregnated with a polyurethane foaming stock solution in any shape such as a hole, groove, or slit.

Next, this processed layered body is inserted into the lower mold 5 for molding as shown in FIG. Let them come into contact with you. When a predetermined amount of polyurethane foaming stock solution is injected into this, the foaming stock solution forms a non-impregnable coating 2 (although it does not impregnate into the layered body 1 in most places, it impregnates the holes, grooves, slits, etc.). In the recess 4, the non-impregnable coating 2 is partially removed and a recess is formed, so the foaming stock solution is impregnated and penetrates into the layered body 1 at this part.
As shown in FIG. 5, when the upper mold 6 is closed and heated to a predetermined temperature to cause foaming, the polyurethane foam 7 is deposited in the space formed between the lower mold 5 and the upper mold 6, forming the non-impregnable coating. It is formed integrally with 2.

After the foam has hardened, the upper mold 6 is removed and removed from the lower mold 5. As shown in FIG. A cushion material 10 exhibiting cushioning properties is obtained. As the foaming stock solution for forming the polyurethane foam 7, stock solutions for general-purpose foams such as flexible polyurethane foams and semi-rigid polyurethane foams can be used, but stock solutions for flexible polyurethane foams are particularly excellent. In addition, it is of course possible to use a foam stock solution with a special treatment. As mentioned above, the method of the present invention
The surface of a polyurethane foam layered body of a predetermined shape is heat-treated to form a non-impregnable coating, and the non-impregnated coating is cut off at a predetermined portion of the layered body to form a concave portion impregnated with a polyurethane foam stock solution. This is done by inserting the processed layered body into a mold and then foaming the polyurethane foaming solution, so the foaming solution injected onto the layered body forms a non-impregnable coating in areas other than the impregnated recesses. It does not impregnate into the layered material.

Therefore, this part has the same cushioning properties as conventional products, and has a sufficient cushioning effect mainly for absorbing vibrations in the vertical direction. On the other hand, near the peripheral edge, the foaming stock solution is sufficiently impregnated into the polyurethane foam layer due to the impregnating recesses, so that after foaming and curing, this area becomes hard. Therefore, when used as a seat, it has an appropriate hardness that can prevent lateral vibration. Therefore, a polyurethane foam cushion material having partially different hardness can be easily obtained.

[Brief explanation of drawings]

1 to 3 are cross-sectional views showing each cutting process of the polyurethane foam layered body used for manufacturing the cushion material according to the present invention, and FIGS. 4 to 5 are cross-sectional views showing each step of the method of the present invention, Further, FIG. 6 is a cross-sectional view of a cushion material manufactured by the method of the present invention.

Claims (1)

[Claims] 1 Heat-treat the surface of a polyurethane foam layered body of a predetermined shape to form a non-impregnable coating, cut out the non-impregnated coating at a predetermined portion of the layered body to form a concave portion impregnated with a polyurethane foam stock solution, and then A method for producing a cushioning material having a texture of partially different hardness, which comprises inserting the processed layered body into a mold and further foaming a polyurethane foaming stock solution.