JPH0611496B2 - Method for manufacturing soft pad with different hardness at front edge - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a seat pad having a soft front edge.

[Conventional technology]

Seat pads for automobiles are manufactured using, for example, urethane foam having a certain hardness. It is desirable that such a seat pad has good operability of pedals and does not have a feeling of pressure on the thigh, but in the case of a product made of urethane foam of a certain hardness, the front edge presses the thigh. Therefore, a method of lowering the height of the front edge portion and stealing the back surface thereof is performed.

[Problems to be solved by the invention]

However, the method of reducing the height of the front edge portion of the seat pad as described above has a design restriction because the front edge portion cannot be increased. Also, compression is improved but softness is not improved. Therefore, it is possible to partially change the hardness of the foam as described in JP-A-59-138423. However, in the method described in the reference, the central portion of the seat pad can be hardened, and the leading edge can be softened, but since all the leading edges are softened,
When sitting on the seat, the bottoming feeling causes a feeling of hitting the insert wire or the like.

The present invention is to solve the above problems, and an object of the present invention is to provide a method of manufacturing a different hardness sheet pad in which the leading edge has a double-layer structure of a low-hardness foam and a high-hardness foam. To do.

[Means for solving problems]

The front edge softening different hardness seat pad manufacturing method of the present invention uses a molding die including an upper die and a lower die in which the front edge portion of the seat pad is divided by a bank, and a front edge die surface of the lower die. 30-70% of the filling amount of the low hardness foam reactive raw material with fast thickening is injected on the above, and the remaining amount of high hardness foam reactive raw material with fast thickening of other portion is injected. It is characterized by reacting and foaming.

The low-hardness and high-hardness foam-reactive raw materials are those that are thickened by the reaction and foam to become foams, and examples thereof include raw materials of polyurethane foam (for example, a mixture of polyol, water, polyisocyanate), and the like. The thickening property is preferably such that the cure time is within 6 minutes. Further, it is preferable that the thickening properties of both are about the same.

The levee is for accumulating liquid low-hardness foam reactive raw material in the part surrounded by the levee so as not to mix with the high-hardness foam reactive raw material injected into other parts. The thickness may be appropriately determined depending on the thickening property of the foam-reactive raw material and the thickness of the sheet pad.

The injection amount may also be appropriately determined depending on the thickening property of the raw material and the thickness of the sheet pad.

It is preferable to inject the low-hardness and high-hardness foam-reactive raw materials almost at the same time, or slightly ahead of the low-hardness foam-reactive raw material.

[Work]

The low-hardness foam reactive raw material is injected on the front edge mold surface of the lower mold that divides the seat pad front edge by the bank, and the high-hardness foam reactive raw material is injected to the other part. By separating them, it is possible to soften only the target part without mixing. Since a low-hardness and high-hardness foam reactive raw material that rapidly thickens is used, it expands due to foaming and crosses the bank, but even if they contact each other, they will join but will not penetrate each other, so an impregnated layer cannot be formed. A foam with low hardness and high hardness can be obtained. Furthermore, since a low-hardness foam-reactive raw material is injected in an amount of 30 to 70% of the filling amount of the front edge portion, the high-hardness foam expanded by foaming is placed on the low-hardness foam, and the front edge portion is It has a double-layer structure consisting of a low hardness foam and a high hardness foam. The injection amount of the low-hardness foam-reactive raw material was set to 30 to 70% of the filling amount of the front edge part because the seat pad was not softened when it was less than 30% and too soft when it exceeded 70%. This is because there is a feeling of bottoming out and a feeling of hitting the insert wire or the like.

〔Example〕

 The present invention will be described with reference to the drawings according to an embodiment.

In this example, as the foam-reactive raw material of low hardness and high hardness, urethane foam raw material of low hardness and high hardness of the all MDI formulation shown in the following table, which can have different hardness according to NCO index, was used.

Explaining the method of forming the seat pad, a lower mold 1 and an upper mold 2 as shown in FIG. 1 are joined by a hinge 3, and the lower mold 1 is connected by a bank 4 to a front edge portion 5, a rear portion 6, and a side portion. As shown in FIG. 2, the mold divided into 7 is opened, and in a state where the mold is opened, a liquid low hardness urethane foam raw material having the above composition is provided in the front edge portion 5 surrounded by the bank 4 of the lower mold 1. 70% of the filling amount of S is injected, and at the same time, the rear portion 6 and the side portion 7 are filled with the liquid high hardness urethane foam raw material H having the above composition to the filling amount required for the rear portion 6 and the side portion 7. The remaining 30% of Part 5 was added and injected. The low-hardness and high-hardness urethane foam raw materials S and H were liquid, but they were not mixed because they were separated by the bank 4 of the lower mold 1. Low hardness and high hardness urethane foam raw material S,
When H thickened and foamed by the reaction and expanded to the edge of the lower mold 1, the upper mold 2 was covered on the lower mold 1 as shown in FIG. 3, and further reacted. The low-hardness urethane foam raw material S was thickened and foamed by the reaction, and became the low-hardness urethane foam S1 on the front edge portion 5 of the lower mold 1 occupying 70% of the cavity of the portion of the molding die. On the other hand, the high-hardness urethane foam raw material H is thickened and foamed by the reaction to become the high-hardness urethane foam H1, and since the injection amount of the raw material is the amount obtained by adding 30% of the filling amount of the front edge portion, In addition to the rear and side portions of the cavity of the molding die, the upper portion of the low hardness urethane foam S1 at the front edge portion was filled. The urethane foam raw materials S and H having low hardness and high hardness both had a fast curing time of 6 minutes, and thus the two did not penetrate into each other, and the impregnated layer could not be formed. After the reaction was completed, the mold was opened and the seat pad as shown in FIG. 4 (a) was taken out. In the seat pad, a slit 14 is formed by the bank 4 of the lower die 1 of the molding die, and the surface is divided by the slit 14 into a front edge portion 15, a rear portion 16, and a side portion 17. As shown in FIG. 4 (b) showing the AA cross section of the seat pad of FIG. 4 (a) and FIG. 4 (c) showing the BB cross section of the seat pad, the upper portion of the front edge has a low hardness. Urethane foam S1 (25% ILD = 15kg: JIS), and urethane foam H with high hardness at the lower part of the front edge and the rear and side parts.
It became 1 (25% ILD = 20 kg: JIS). Therefore, the front edge portion has a double-layered structure in which the upper portion has low hardness and the lower portion has high hardness.

In this embodiment, the upper die and the lower die are connected to each other by the hinge as the forming die, but the upper die and the lower die may be shifted to each other.

〔The invention's effect〕

The present invention encloses the front edge of the lower mold with a bank as described above, and injects 30 to 70% of the filling amount of the low-hardness foam-reactive raw material having a rapid thickening into this portion, and fills the other portion with high viscosity. Since it is manufactured by injecting a hard foam reactive material, the front edge can have a double structure of a low hardness foam at the top and a high hardness foam at the bottom. It is possible to manufacture a seat pad that does not press the portion and does not have a bottoming feeling when sitting and a hitting feeling such as an insert wire.

Further, although the slit is provided, the front edge portion can be raised or the seat pad can be freely designed.

Furthermore, the lower mold is divided by a bank, and various kinds of different hardness foams in which only the intended portion is softened can be produced by appropriately adjusting the injection amount of the raw material, which has a wide range of applications.

[Brief description of drawings]

FIG. 1 is a partial top view of a molding die according to an embodiment of the present invention, FIG. 2 is a sectional view of a molding die into which a low-hardness and high-hardness urethane foam raw material according to an embodiment of the present invention is injected, and FIG. Is a cross-sectional view of a mold for foaming a low-hardness and high-hardness urethane foam raw material according to an embodiment of the present invention, and FIG. 4 (a) is a top view of a seat pad manufactured according to an embodiment of the present invention. 4 (b) is a sectional view taken along the line AA of the seat pad of FIG. 4 (a), and FIG. 4 (c) is B of the seat pad of FIG. 4 (a).
A B sectional view is shown. In the figure, 1 ... lower mold, 2 ... upper mold 4 ... bank, 5 ... front edge S ... low hardness urethane foam raw material H ... high hardness urethane foam raw material

Claims (1)

[Claims] 1. A low-hardness foam reaction with a rapid increase in viscosity on the die surface of the front edge portion of the lower die, using a forming die comprising an upper die and a lower die whose front edge portion is partitioned by a bank. 30% to 70% of the filling amount of the elastic raw material, and the remaining amount of the high-hardness foam-reactive raw material with rapid thickening is injected into the other portion to cause reaction and foaming. Manufacturing method of softened different hardness seat pad.