JPH02292007A - Molding method of foam body and its mold - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of foaming urethane resin or the like to obtain foam molded products such as cushions and automobile seats, and particularly relates to a method of foaming urethane resin or the like to obtain foam molded products such as cushions and automobile seats. The present invention relates to a method of simultaneously foaming and molding, and a mold used for the molding.

[Prior Art] Foam molded products in which foams of different hardness are integrated are known. For example, in car seats, in order to improve the holding and cushioning properties of the seated person's body, the backrest and seat where the back and buttocks of the seated person are located are molded with soft urethane foam. Side supports with slightly raised sides on both sides are molded from hard urethane foam. Foam molded products with different hardnesses are produced by using foaming solutions with different foaming pressures and cell strengths, and by simultaneously foaming these foaming solutions in the same mold. [Problems to be Solved by the Invention] However, when different foaming stock solutions are foamed in the same mold, defoaming occurs in the foams with lower foaming pressure and cell strength, and sufficient foaming cannot be achieved. For this reason, it is conceivable to divide the inside of the mold with partition plates and foam each foaming solution in each foaming chamber, but in this case, it would be difficult to integrate the foam. SUMMARY OF THE INVENTION Therefore, the present invention provides a foaming method that does not cause defoaming of the foam and allows the foam to be integrated when foaming different foaming stock solutions in the same mold, and a mold for forming a foam. It is something.

[Means for Solving the Problems] The present invention provides a method for forming a foam by simultaneously foaming different foaming stock solutions in a mold, in which the inside of the mold is divided into a plurality of foaming chambers by a partition plate, and adjacent foaming It is characterized by covering the gap between the mold and the partition plate by stretching coarse felt across the chambers, and simultaneously foaming the foaming solution in each foaming chamber in this stretched state. Furthermore, the mold for forming a foam according to the present invention is characterized in that the inside of the mold is divided into a plurality of foaming chambers by a partition plate, and the gap between the partition plate and the mold is closed with coarse felt buried in the molded body. There is. [Function] In the present invention, the foam adjacent to the coarse wool felt stretched between the foaming chambers is impregnated and acts to join both foams, and a different foaming stock solution is injected into each foaming chamber to cause simultaneous foaming. It looks like this. By inserting coarse wool felt into the gap between the partition plate and the mold and compressing it, the dividing area between the foams of different hardness has a higher surface rigidity and is stronger against bending. By inserting coarse wool felt into the gap between the partition plate and the mold and compressing it, the sealing performance of the mold is improved and defoaming due to the stretching of the cold cured foam is prevented. [Example] Fig. 1 shows a mold used in the present invention, which includes a lower mold 1 and an upper mold 2. The lower mold 1 has a plurality of partition plates 3, 3... extending toward the upper mold 2, and when the upper mold 2 is butted against the lower mold l, the inside of the mold is filled with a plurality of foaming chambers 4a.
, 4b... These foaming chambers 4a, 4b,
Foaming stock solutions with different foaming pressures or cell strengths are injected into .... In such a mold, a coarse felt 5 is provided on the partition plate 3 portion. The coarse felt 5 is placed in the upper mold 2 so as to be stretched over the adjacent foaming chambers 4a and 4b, 4b and 4c.
It is provided to close the gap between the foaming chamber and the partition plate 3, and adjacent foaming chambers are connected by a coarse felt 5. If the foaming stock solution is foamed at the same time with such coarse wool felt 5 stretched across adjacent foaming chambers, defoaming on the foam side with low foaming pressure and cell strength will be lost. Further, during foaming, each foaming chamber 4a, 4b. Since the foam molded in ... is joined by the coarse felt 5, it is well integrated. FIG. 2 shows the mold before injection of the foaming solution, in which the coarse felt 5 is temporarily fixed to the upper mold 2 so as to face each partition plate 3, 3, and so on. are butted against the lower mold l, and then each foaming chamber 4a, 4b...
・Foaming stock solution is injected inside. Simultaneous foaming is then carried out in each foaming chamber, making it possible to obtain a foam molded product in which foams of different hardness are integrated. In such a method, the divided foaming chambers can be set to different conditions, for example, cold curing can be performed in the foaming chambers 4a and 4c, and hot curing can be performed in the foaming chamber 4b. Furthermore, even when cold curing is performed in all foaming chambers, foams with different strengths can be foamed simultaneously by changing the packing ratio. Next, we will show a specific example of foam molding using such a mold. Molding example l ■Foam formulation Hot cure foam formulation Polyether polyol I00pbw water
3.5 Tertiary amine
Tin bioctylate
0.1 Silicone foam stabilizer TDI-80 Cold cure foam Polyether polyol polymer polyol water Tertiary amine Silicone foam stabilizer Crosslinker MDI-TM-20 ■Liquid temperature 25℃ for each formulation ■Mold temperature Hot cure foam 40°C Cold cured foam 60°C Under the above conditions, using the mold shown in FIG.
B was filled with hot cure foam and molded. The molded product has coarse felt felt embedded in the disassembled parts between each foam body, and this felt is impregnated with 1.0 (index 100) foam to increase the surface rigidity and the bending rigidity of this part. In addition, no defoaming occurred in the cold-cured foam portion, and a foam body with the desired elasticity was obtained. [Comparative Example] Molding was performed under the same conditions as above using the mold shown in Figure 1 (there is a gap between the partition plate and the upper mold) without using coarse felt. In the molded product, each foam is bonded to each other through the gaps in the mold, but defoaming occurs on the bonded surfaces. Because of this defoaming, the tensile strength of the divided portion between each foam body is about half that of the material at breakage.

In addition, the foaming pressure throughout the mold becomes the same through the gap between the partition plate and the upper mold, and in the case of cold-cured foam, the back rate (molded product foam density / free foam density) increases and cannot be made hard, so the crosslinking agent As a result, a molded article with reduced impact resilience was obtained.

Molding Example 2 In the case of cold cure foam, the hardness can be easily changed by changing the packing ratio. In the mold shown in Figure 1, the space between the upper mold and the partition plate is closed with coarse felt, so each foaming chamber can have independent foaming pressure. The bank is hard,
Even when molding something with a soft central cushion part, it can be easily molded by changing the back ratio using one type of urethane foam formulation.

On the other hand, in molds that do not use coarse felt, the foaming pressure between the upper mold and the partition plate is uniform in each foaming chamber, and the packing ratio cannot be changed. When molding a cushion, two different urethane foam formulations are required for the bank and cushion parts. [Effects of the Invention] As explained above, the present invention has a partition plate and a molding. Since the gap between the two foams is closed with coarse felt embedded in the foam body, when different foaming stock solutions are foamed simultaneously in each foaming chamber, molding can be performed without defoaming and in which each foam is integrated. Can be done. This felt is then impregnated with foam, increasing its surface rigidity and improving the bending rigidity of the divided parts of each foam body. Further, even when hot cure foam and cold cure foam are foamed simultaneously, defoaming does not occur in the cold cure foam portion at all, and a foam body having desired elasticity can be obtained.

Furthermore, according to the present invention, each foaming chamber divided by a partition plate can be set to an independent foaming pressure, so by varying the packing ratio, molded products of different hardness can be produced using one type of foaming stock solution. It can be obtained easily.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of a mold in the foaming process of the present invention. l...lower mold, 2...upper mold, 3...partition plate, 5...
・Coarse wool felt,

Claims (2)

[Claims] (1) In a method of forming a foam by simultaneously foaming different foaming stock solutions in a mold, the inside of the mold is divided into a plurality of foaming chambers by a partition plate, and coarse wool felt is stretched between adjacent foaming chambers. A foam molding method characterized in that the gap between the mold and the partition plate is closed, and the foaming stock solution is simultaneously foamed in each foaming chamber in this spanning state. (2) A mold for forming a foam, characterized in that the inside of the mold is divided into a plurality of foaming chambers by a partition plate, and the gap between the partition plate and the mold is closed with coarse felt buried within the molded body.