JPS6273919A - Manufacture of seat cushion - Google Patents

Abstract

PURPOSE:To obtain a seat cushion which is comfortable to sit on, by a method wherein urethane foam raw materials are cast into each of cavities of a top and bottom forces by varying either compounding or a fill at least and foamed and the top and bottom forces are closed in the midst of gas blowing reaction. CONSTITUTION:Urethane foam raw materials 20a whose fill and compounding have been selected are cast into a cavity 16 of a top force 12 so as to form a rather hard cushion pad. The urethane foam raw materials 22a whose fill and compounding have been selected are cast into a cavity 18 of a bottom force 14 so that a cushion pad formed of the raw materials 22a becomes softer than that formed of the raw materials 20a cast into the top force. As for a foamed thing composed of the urethane foam raw materials 20a, 22a, which have been kept foamed independently by closing an expansion molding tool 10 in the midst stage of gas blowing reaction of the urethane foam raw materials 20a, 22a cast into both the cavities 16, 18, the gas blowing reaction is advanced by unifying the thing and turned into a seat cushion having the rather soft cushion pad part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a seat cushion in which the upper and lower parts have different hardnesses.

(Prior Art) Seat cushions for vehicles or furniture are preferably ones that first give a soft feel when sitting on the seat, and can then support the user's body weight without giving a feeling of bottoming out.

By the way, in order to obtain such a seat cushion, it is necessary to make the upper part of the cushion soft and the lower part hard. Conventionally, the following manufacturing method has been proposed.

■ A method of laminating and bonding two cushion pads of different hardness, each molded into a predetermined shape, using an adhesive. ■ A method of forming the cushion pad that forms the upper or lower part of the seat cushion in advance, and a method of placing the cushion pad in a foam mold and integrally molding other cushion pads having different hardness within the foam mold;
■The inside of the foam mold is divided into upper and lower parts by shutters, and cushion pad forming raw materials with different hardness compositions are injected into the partitioned upper and lower spaces and foamed, and the shutters are pulled out during foaming to separate the upper and lower cushion pads. This is a way to unify them.

However, the problem with method (■) is that it takes time to mold and laminate the two cushion pads, and the problem with method (■) is that the cushion pad placed in the foam mold must be molded in advance, and the foam Yu injected into the mold.

Regarding the problem of the raw material for forming Shonpazod impregnating the surface of the Tabjoon pad placed in the mold and hardening, forming a very hard layer that is almost non-emitting, making it uncomfortable to sit on, and method (2). There are two problems: the timing of pulling out the shutter is difficult; and when the shutter is pulled out, air bubbles on the surface of the cushion pad that were in contact with the shutter collapse, forming a very hard layer, making it uncomfortable to sit on.

(Problems to be Solved by the Invention) This invention has been made to solve the above-mentioned problems, and provides a manufacturing method that allows a comfortable seat cushion to be obtained through simple operations. be.

(Means for Solving the Problems) This invention provides for changing at least one of the composition or filling amount in each cavity of the upper mold and the lower mold of a foam molding mold which forms one cavity in the shape of a seat cushion when the mold is closed. The special solution is to inject the urethane foam raw material, foam it, and close the upper and lower molds during the foaming reaction.

(Function) The urethane fort raw material injected into each cavity is
As the foaming reaction progresses, the volume increases and fills the cavity while pressing against the inner surface of the cavity. That is, the reaction of the urethane foam raw material proceeds in a state in which the surface of the foamed product during foaming and the inner surface of the cavity are pressed against each other.

Therefore, the foamed material in the upper mold, which is closed during foaming, is retained without falling from the upper mold, continues to react, and then reacts with the foamed material in the lower mold cavity in the middle of foaming. Finished and becomes one seat cushion.

The seat cushion formed in this way is formed from urethane foam raw materials injected into the upper mold cavity and the lower mold cavity, respectively, and consists of two cushion pads with different hardnesses stacked one above the other. . Moreover, since the upper mold cavity and the lower mold cavity are integrated during the foaming reaction of the urethane foam raw material, the urethane foam raw material in each cavity becomes integral from the middle and the reaction proceeds. The resulting seat cushion is free from the risk of forming a hard layer between the upper and lower cushion pads.

(Embodiment) FIGS. 1 to 3 are cross-sectional views illustrating the manufacturing process of an embodiment of the present invention.

An embodiment of the present invention will be described below with reference to these drawings, with reference to step j.

[]) Raw material injection process into the upper mold cavity (Fig. 1) 10
is a foam mold. This foaming mold 10 has an upper mold 12
and a lower mold 14, and cavities 16 and 18 are formed in the upper mold 12 and the lower mold 14. The cavities 16 and 18 come together to form a seat cushion shape when the mold is closed.

Then, the urethane foam raw material 20a is injected into the cavity 1G of the upper mold 12. The filling amount and composition of the urethane foam raw material 2Qa are selected so as to form a hard cushion pad.

(2) Raw material injection step into the lower mold cavity (FIG. 2) Next, the urethane foam raw material 22a is injected into the lower mold cavity 18. The composition and filling amount of this urethane 7 ohm [1) 22a are selected so as to provide a softer cushion pad than the cushion pad formed from the urethane foam raw material 20a injected into the upper mold. Note that the timing of injection of the urethane foam raw material 22a is as follows:
It is appropriately selected depending on the reaction rate of the ohmic raw materials 20a and 22a, etc., and both raw materials may be injected at the same time or in the opposite manner to the above. This embodiment shows an example in which the urethane foam base M'420a is first injected into the upper mold cavity 1G.

(3) Closing process of foam mold (Fig. m3) Both cavities 1
6. In the middle of the foaming reaction of the urethane foam raw materials 20a and 22a injected in step 18, the foaming mold 10 is closed. As a result, the foamed material consisting of the urethane foam raw materials 20a and 22a, which had been foamed independently in both cavities, is then integrated into a foaming reaction and becomes a sheet cushion.

FIG. 4 is a sectional view of the seat cushion 24 which has been removed from the mold after a predetermined period of time has elapsed. In the figure, 20 is the upper mold cavity 1
G is a hard cushion pad portion formed from the urethane foam raw material #J20a injected, and 22 is a soft cushion pad portion formed from the urethane foam raw material 22a injected into the lower mold cavity 18.

(Effects of the Invention) This invention manufactures a seat cushion with a monolayer structure in which the upper part is soft and the lower part is hard by injecting urethane foam raw materials into both the upper and lower cavities of a foam mold. Therefore, there is no need for the conventional troublesome work of gluing two cushion pads of different hardness, and seat cushions can be manufactured with simple work.

In addition, the resulting seat cushion has a soft upper part and a hard lower part, and no hardened layer is formed at the boundary between the soft and hard parts, making it comfortable to sit on.Furthermore, since the lower part is hard, it is difficult to support the load. becomes larger, so
The thickness can be reduced.

[Brief explanation of drawings]

1 to 3 are cross-sectional views illustrating the steps of a crystal manufacturing method according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a seat cushion obtained by implementing the present invention. 12 upper mold, 14 lower mold, 20 a, 22 a
Ureta 77 ohm

Claims (1)

[Claims] Urethane foam raw materials are injected into the upper and lower cavities of the foam molding mold, which form one seat cushion-shaped cavity when the mold is closed, with at least one of the blending ratio and filling amount being changed, and the foaming process is performed. A method for manufacturing a seat cushion, which comprises closing an upper mold and a lower mold during the reaction.