JPH01238910A - Manufacture of different hardness cushioning body - Google Patents

Abstract

PURPOSE:To obtain a highly rigid and different hardness cushioning body, the bottom face of which has no irregular shape by a method wherein forming stock is poured in a force cavity, at the upper part of which a reinforcing sheet having interconnecting pores is furnished, so as to be integrally molded and, after an impregnating reinforcing material is furnished at the upper part of adjacent cavities and onto the reinforcing sheet, forming stock is poured in a force cavity so as to be integrally molded. CONSTITUTION:Under the state that a reinforcing sheet 32 made of foam having interconnecting pores, is furnished onto the cavity surface of a top force 38a and, foaming is done under the state that forces are closed by pouring liquid foaming stock 28a in the cavity 36 of the forces 38. Due to the reticulate skeleton of the reinforcing sheet, the liquid foaming stock cures in the reinforcing sheet 32 being kept under lowly foamed state. Next, under the condition that the low hardness foam 28, which is released from the forces 38, is furnished to a low hardness foam housing cavity 46a with the reinforcing sheet 32 side directing upward and an impregnating reinforcing material 34 is furnished onto the cavity surface of a top force 44b, liquid formed foaming stock 30a is poured so as to impregnate the reinforcing sheet 32 and the impregnating reinforcing material 34 with the stock, resulting in hardening the stock under the state that its foaming is restricted within the impregnating reinforcing material 34. Thus, a high hardness foam having the hardened impregnating reinforcing material 34 at its bottom face integrally or a different hardness cushioning body 26 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a cushion body of different hardness, which partially has different hardness.

(Prior art) In a cushion body constituting a seat, for example, as in the seat cushion body 10 shown in FIG. 9, side portions 10a are made harder than the central portion 10b in order to maintain the sitting posture. Cushion bodies with different hardness are preferred.

Conventionally, as a simple manufacturing method of the above-mentioned cushion body of different hardness,
There are the following manufacturing methods. FIG. 10 is a sectional view of a mold for manufacturing a cushion body of different hardness by the manufacturing method. The mold 12 used has a partition 16 erected in the cavity 14 so that the inside of the cavity is separated from the central part 18.
The cavity is partitioned into a central portion 18a and both side portions 18b, and the central portion 18a and both side portions 18b are in communication with each other at the upper portion of the cavity. And the center part 1 of the cavity
A liquid foam raw material 20a that forms a soft (low hardness) foam is injected into the cavity 8a, and a liquid foam raw material 20b that forms a hard (high hardness) foam is injected into both sides 18b of the cavity. The shown cushion body 10 of different hardness is integrally foam-molded.

In addition, the liquid foaming raw materials 20a and 20b have different compositions, cases where the same composition is used and only the injection ratio (commonly known as pack ratio) to each cavity is different, and further combinations and injection ratios. There are cases where the two are different.

(Problem to be Solved by the Invention) However, in the above manufacturing method, the central portion 10b
During molding of the low-hardness foam part (the low-hardness foam part is also shown as 10b), the foaming gas released from the liquid foaming raw material or the air that was in the cavity is chased to the upper part of the cavity. A recess consisting of a gas pocket (commonly known as an air pocket) is formed on the bottom surface 10c of the low-hardness foam (depending on the use of the cushion of different hardness, it may also be the back surface, but will be referred to as the bottom surface below), which is shaped by the inner surface of the foam. Therefore, there is a problem that a cushion body of different hardness having a desired bottom shape cannot be obtained.

In addition, in cushion bodies of different hardness used for seats, etc., a spring is often disposed on the bottom surface 10c side to improve cushioning properties. will be strongly pushed. Therefore, if the bottom surface 10c has an irregular concave shape formed by the air pockets, the strength of the bottom surface 10c is reduced at the chain portions, resulting in a problem of easy damage and reduced durability.

Furthermore, in the cushion body of different hardness obtained by the above manufacturing method, the bottom surface of the low hardness foam also has low rigidity.

Therefore, the surface of the low-hardness foam is loaded (weight) at the center.
If the load is applied, the entire bottom surface will not be able to support the load,
Only the part to which that load is applied will flex significantly.

As a result, only the portion to which the load is applied is significantly bent, and the spring supporting the bottom of that portion is compressed and deformed to a large extent, so that a large elastic repulsive force is generated in that spring. Since the bottom surface of the low-hardness foam is strongly pressed by the large elastic repulsive force, there is a problem in that a feeling of bottoming out occurs and the cushioning properties are deteriorated.

Furthermore, depending on the shape of the cushion body of different hardness, it may not be possible to provide sufficient thickness at the joint between the low-hardness foam and the high-hardness foam, and in such a case, the joint area will also become small, resulting in a lack of joint strength. There is a problem in that the low-hardness foam and the high-hardness foam tend to separate at the joint.

On the other hand, cushion bodies of different hardness are covered with a skin and used for seats, etc. Then, in order to prevent wrinkles from forming on the epidermis, the epidermis is applied to the surface of the cushion body of different hardness while pulling the epidermis. However, the cushion body 10 of different hardness obtained by the above method has a concave shape 22 between the low hardness foam and the high hardness foam due to the partition 16 erected on the mold cavity surface. Corner 24 on the surface
is formed. As a result, the soft corners 24 are compressed and deformed when the skin is applied, causing problems such as the product's shape being distorted and the skin being wrinkled.

This invention was made in view of the above points, and aims to (i) provide a cushion body of different hardness that does not have an irregular shape consisting of air pockets on the bottom surface and has high rigidity on the bottom surface, and (ii) further In addition to (i), it is an object of the present invention to provide a cushion body of different hardness, which has a high bonding strength between a low-hardness foam and a high-hardness foam, and whose shape does not easily collapse when attached to the skin.

(Means for Solving the Problems) The present invention provides a method for manufacturing a cushion body of different hardness, in which two or more foams having different hardness are integrally foam-molded from two or more liquid foaming raw materials injected into a mold. ■A reinforcing sheet made of foam that has continuous holes is installed on the upper inner surface of a predetermined part of the mold cavity, and a liquid foaming raw material is injected into the predetermined part of the cavity, and the foaming process is performed to form a low-hardness sheet that has the reinforcing sheet integrated into it. forming a foam; [2] then installing a series of impregnable reinforcing material in the upper part of the cavity adjacent to the low-hardness foam and in the cavity on the reinforcing sheet of the low-hardness foam; and by injecting a liquid foaming raw material into a mold cavity adjacent to the low-hardness foam and foam-molding a high-hardness foam that is integrated with the low-hardness foam and the impregnable reinforcing material, the above objective (i) can be achieved. This is what we aim to achieve.

Furthermore, in the above solution, the bonding surface of the low-hardness foam to be bonded to the high-hardness foam is inclined so that it protrudes toward the high-hardness foam as it approaches the surface of the low-hardness foam. The aim was to achieve ii).

(Function) First, the liquid foaming raw material injected into the predetermined part of the cavity,
A low-hardness foam is formed by filling the inside of the cavity with foam, impregnating it with a reinforcing sheet made of foam mainly having continuous air holes, which is installed on the upper inner surface of a predetermined part of the cavity, and having the reinforcing sheet integrally on the bottom surface. Form. At this time, the foaming gas generated from the liquid foaming raw material and the gas that was previously present in the cavity are driven to the upper part of the cavity due to the increased volume of the liquid foaming raw material. Since the reinforcing sheet is installed in the device, the particles penetrate into the reinforcing sheet and disperse within the reinforcing sheet.

Therefore, the bottom surface of the low-hardness foam is not affected by foaming gas or the like, and irregular recesses consisting of air pockets are not formed.

Further, the liquid foaming raw material impregnated into the reinforcing sheet is prevented from freely foaming by the mesh skeleton of the foam constituting the reinforcing sheet, and hardens within the reinforcing sheet in a low foaming state. Therefore, the reinforcing sheet after being impregnated and cured with the liquid foaming raw material becomes extremely hard, and a low-hardness foam having the reinforcing sheet integrally on the bottom surface has a high rigidity on the bottom surface.

Next, in the upper part of the cavity adjacent to the low-hardness foam and on the reinforcing sheet of the low-hardness foam,
A series of impregnable reinforcement is installed and liquid foam material is injected into the cavity over the reinforcement sheet and adjacent to the low stiffness foam. The liquid foaming raw material injected onto the reinforcing sheet of low-hardness foam impregnates the reinforcing sheet and the impregnable reinforcing material in the upper part of the cavity, and foams and hardens the reinforcing sheet and the impregnable reinforcing material together. However, the foaming is limited by the network skeleton constituting the reinforcing sheet and the fibers constituting the impregnable reinforcing material, and as a result, the reinforcing sheet becomes even harder, and the impregnable reinforcing material also becomes harder. Therefore, on the bottom surface of the low-hardness foam, the hard reinforcing sheet and the impregnable reinforcing material after being impregnated and hardened with the liquid foaming raw material are laminated together. In addition, the liquid foaming material injected into the cavity adjacent to the low-hardness foam fills the cavity by foaming, adheres to the adjacent low-hardness foam, and impregnates the impregnable reinforcing material above the cavity. Foaming is restricted within the impregnable reinforcement and cures to form a low stiffness foam and a high stiffness foam integrated with the impregnable reinforcement. The impregnated reinforcing material on the bottom surface of the high-hardness foam (or the back surface depending on the use of the cushion with different hardness) is made by hardening the impregnated liquid foam raw material in a low-foamed state, so it is extremely hard. The bottom surface of the high-hardness foam has increased rigidity and strength. Also,
Since the impregnated reinforcing material connects the bottom surfaces of the high-hardness foam and the low-hardness foam, the low-hardness foam and the high-hardness foam are also firmly connected and bonded thereby. Furthermore, the foaming gas generated during molding of high-hardness foams and the air in the cavity penetrate into the impregnated reinforcing material and disperse in the same way as the reinforcing sheet described above. Irregular concave shapes consisting of air pockets are not formed on the bottom surface.

The thus integrally formed foam is soft in its low-hardness foam portions and hard in its high-hardness foam portions, resulting in a cushion body with different hardness that partially differs in hardness. Moreover, since the low-hardness foam part has two layers on the bottom surface of the reinforcing sheet made hard by impregnating and hardening the liquid foam raw material and the impregnated reinforcing material, the bottom surface has extremely high rigidity.

On the other hand, in the case where the bonding surface with the high-hardness foam in the low-hardness foam is formed so as to protrude toward the high-hardness foam as it approaches the surface of the low-hardness foam, the following effect can be obtained.

The obtained cushion body of different hardness has a high bonding strength because the bonding area between the low hardness foam and the high hardness foam becomes large due to the inclination of the bonding surfaces.

In addition, due to the slope of the joint surface, the low-hardness foam covers the high-hardness foam in the low-hardness foam portion around the joint, so the surface of the low-hardness foam around the joint becomes , hardened by high hardness foam inside. As a result, when covering a cushion body with different hardness with a skin, even if the surface of the low-hardness foam is pressed by the tension of the skin around the joint, the surface shape of the low-hardness foam does not collapse, and the skin wrinkles are less likely to form on the skin.

(Example) Examples will be described below with reference to the drawings. 1st
3 to 3 are cross-sectional views of a mold showing the production of a cushion body of different hardness for a seat according to an embodiment of the present invention, and FIG. 4 is a sectional view of a cushion body of different hardness for a seat 26 manufactured thereby.
FIG.

First, the cushion body 26 of different hardness for a seat shown in FIG. 4 will be explained. The cushion body 26 of different hardness for a seat constitutes the seat portion of an automobile seat, and in order to maintain the occupant posture when the automobile rotates, the center portion is made of a low-hardness foam 28,
Both sides are made of high-hardness foam 30. A reinforcing sheet 32 is integrally formed on the bottom surface of the low-hardness foam 28, and an impregnable reinforcing material 34 is integrally bonded to the reinforcing sheet 32 and the bottom surface of the high-hardness foam 30. The reinforcing sheet 32 is a hard material made by impregnating and hardening the liquid foaming material that forms the low-hardness foam 28, and the impregnable reinforcing material 34 is also made by impregnating and hardening the liquid foaming material that forms the high-hardness foam 30. It has become hard.

Note that the hardness of the low-hardness foam 28 and the high-hardness foam 30 is determined as appropriate depending on the use of the cushion body of different hardness. Also,
The terms "low hardness" and "high hardness" in this specification are used in a relative sense, and do not indicate an absolute meaning; one is "softer" to a desired degree than the other. or "Hard J."

Next, a method of manufacturing the cushion body of different hardness for a seat will be explained.

First, the low hardness foam 28 is molded. The low-hardness foam 28 is molded using a mold 38 having a cavity 36 of a predetermined shape, as shown in FIG. A reinforcing sheet 32 made of foam is installed using pins (not shown) set up on the upper mold cavity surface,
A liquid foaming raw material 28a such as a polyurethane raw material is injected into the cavity 36 and foaming is performed in a closed mold state. It is impregnated into the reinforcing sheet 32 on the cavity surface, resulting in a low-hardness foam having the reinforcing sheet 32 integrally on the bottom surface. At that time, the liquid foaming raw material impregnated into the reinforcing sheet 32 is restricted from foaming due to the mesh skeleton of the foam constituting the reinforcing sheet, and hardens within the reinforcing sheet 32 while maintaining a low foaming state. The reinforcing sheet becomes extremely hard.

Next, high hardness foam 30 is placed on both sides of the low hardness foam 28.
to form. The high-hardness foam 30 is molded using a mold 44 shown in FIG.

The mold 44 has a cavity 46a that accommodates the low-hardness foam 28 therein, and cavities 46b for forming the high-hardness foam that are in contact with both sides of the cavity 46a. Further, on the cavity surface of the lower mold 44b, a partition 48 for positionally fixing the low-hardness foam 28 is provided at the boundary between the low-hardness foam housing cavity 46a and the high-hardness foam forming cavity 46b.
is provided with a gap left at the top of the cavity.

The mold 38 is placed in the low hardness foam accommodation cavity 46a.
The low hardness foam 28 taken out from the reinforcing sheet 32ff
1 is placed upward, and the impregnable reinforcing material 34 is placed in the cavity of the upper mold 44b using a bottle or the like set upright on the cavity surface. The impregnable reinforcing material 34 is made of a material impregnated with a liquid foaming material such as wool felt or cotton cloth, and is installed continuously above the low-hardness foam housing cavity 46a and the high-hardness foam forming cavity 46b. Then, a liquid foaming material 30a such as a polyurethane foam material is injected onto the low-hardness foam reinforcing sheet 32 and into the high-hardness foam forming cavity 46a, and the mold is closed.

The liquid foaming raw material 30a injected onto the reinforcing sheet 32 is
The reinforcing sheet 32 and the impregnable reinforcing material 34 are impregnated, and foaming is restricted by the mesh skeleton that makes up the reinforcing sheet 32, the fibers that make up the impregnable reinforcing material 34, etc., and the material reacts and hardens with almost no foaming. The impregnable reinforcing material 34, which has become harder, adheres to the reinforcing sheet 32. Further, the liquid foaming raw material injected into the cavity 46b for forming a high-hardness foam fills the cavity 46 by a foaming reaction, and the partition 4
8 is bonded to the low hardness foam 28 in the gap above the cavity, and is impregnated into the impregnable reinforcing material 34 at the upper part of the cavity, so that foaming is restricted within the impregnable reinforcing material 34 in the same manner as above, and the reaction occurs in a low foaming state. Impregnable reinforcement material 3 cured and thereby hardened
4 integrally on the bottom surface.

Then, when the molded product is taken out from the mold 44, a cushion body 26 of different hardness shown in FIG. 4 is obtained.

The liquid foaming raw material 30a may have a different composition from the liquid foaming raw material 28a forming the low-hardness foam, or the same composition may be injected into the cavity with a higher packing ratio. Also, the mold for forming the low-hardness foam and the mold for forming the high-hardness foam may be common,
FIG. 3 is a sectional view of the common type 50. This mold 50 has the same structure as the molds 38 and 44 described above, except that a nest 52 is fitted as shown in this figure when forming a low-hardness foam, and the nest 52 is removed when forming a high-hardness foam. If this mold 50 is used, manufacturing operations can be performed continuously without moving the low-hardness foam from mold to mold.

On the other hand, FIGS. 5 and 6 are cross-sectional views of a mold during manufacture in another embodiment, and FIG. 7 is a cross-sectional view of a cushion body 54 of different hardness for a seat obtained by the manufacture.

The different hardness cushion body 54 has a joining part 60 between the low hardness foam 56 and the high hardness foam 58 that is inclined, and protrudes into the high hardness foam 58 as it approaches the surface. It consists of the same configuration as .

This cushion body 54 of different hardness has a high rigidity at the bottom like the cushion body 26 of different hardness described above, and in addition, the surface of the low hardness foam around the joint with the high hardness foam is affected by the influence of the high hardness foam inside. It has become harder.

The cushion body 54 of different hardness is manufactured in the same manner as the cushion body 26 of different hardness except that the low hardness foam 56 is formed using the mold 62 shown in FIG.
Only the main points will be explained below.

The mold 62 has a structure in which both sides 64a of a cavity of an upper mold 62a forming the bonding surface 60 of the low-hardness foam are inclined, and the cavity 64 expands downward.

A reinforcing sheet 32 is placed on the cavity surface of the upper mold 62a of the mold 62.
A low-hardness foam 56 having a hard reinforcing sheet 32 impregnated with the liquid foaming material and hardened thereon is formed by a foaming reaction by injecting the liquid foaming material 58a. The formed low-hardness foam 56 has a bonding surface 6 with the high-hardness foam.
0 protrudes toward the high hardness foam as it approaches the surface of the low hardness foam.

Note that the low-hardness foam 28 whose both side surfaces serving as joint surfaces are not sloped is formed using the mold 38 in FIG. may be formed.

Next, the low-hardness foam 56 is placed in the low-hardness foam storage cavity 46a of the same mold 44 as described above, as shown in FIG. 6, with the reinforcing sheet 32 facing upward. At that time, low hardness foam 5
A gap 66 that widens upward is formed between the joint 60 with the high-hardness foam at 6 and the partition 48 of the lower mold.

Then, the impregnable reinforcing material 34 is mounted on the entire upper die cavity surface, and the liquid foaming raw material 58a is injected into the cavity 46b and onto the reinforcing sheet 32, thereby forming the low-hardness foam 56 and the impregnable reinforcing material hardened by impregnation and curing. A high-hardness foam 58 is formed integrally with 34. After that, the molded product is molded into mold 44.
When taken out, a cushion body 54 of different hardness as shown in FIG. 7 is obtained.

Further, FIG. 8 is a longitudinal cross-sectional view of a cushion body 68 of different hardness for a seat backrest obtained by another implementation of the present invention. In FIG. .

(Effects) The present invention has the above-mentioned configuration and has the following effects.

First of all, it is possible to obtain a cushion body of different hardness with high rigidity on the bottom surface, so when used for a seat, etc., the load is supported by the entire bottom surface, and because one part does not bend significantly, it is difficult to feel the bottoming out feeling. There is a certain effect.

In addition, since irregular recesses consisting of air pockets are not formed on the bottom surface of the cushion body of different hardness, the strength of the bottom surface will not be partially weakened, and even if a spring is placed on the bottom surface, there is no risk of damage to the bottom surface. This has the effect of improving durability.

Moreover, there is also the effect that a desired shape can be obtained without irregular recesses or the like on the bottom surface.

Furthermore, when the bonding surface of the low-hardness foam with the high-hardness foam is inclined so that it protrudes toward the high-hardness foam as it approaches the surface, the following effect is produced in addition to the above-mentioned effects.

First, since the bonding area between the low-hardness foam and the high-hardness foam in the cushion body of different hardness increases, the bonding strength increases, which makes it difficult for the low-hardness foam and the high-hardness foam to separate. .

In addition, since the surface hardness of the low-hardness foam increases around the joint with the high-hardness foam, when attaching the skin to the cushion body of different hardness, the tension of the skin increases (
Even if it is applied to the corners), the surface is less likely to deform and lose its shape, and it also has the effect of reducing the occurrence of wrinkles on the epidermis.

4. Description of the hour wheel drawings Figures 1 to 3 are cross-sectional views of molds for manufacturing cushion bodies of different hardness according to the present invention, and Figure 4 is a cushion body of different hardness obtained by implementing the present invention. , FIGS. 5 and 6 are cross-sectional views of a mold for manufacturing a cushion body of different hardness according to another embodiment of the present invention, and FIGS. 7 and 8 are cross-sectional views of another example of the mold produced according to the present invention FIG. 9 is a cross-sectional view of a cushion body of different hardness obtained by a conventional manufacturing method, and FIG. 10 is a cross-sectional view of a mold for manufacturing a cushion body of different hardness by a conventional manufacturing method.

28.56: Low hardness foam, 28a, 30a: Liquid foaming raw material, 30.58: High hardness foam, 32: Reinforcement sheet, 34: Impregnable reinforcement material,
38.44.62: Mold, 60: Joint surface Patent applicant Inoue MBC Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (2)

[Claims] (1) In a method for manufacturing a cushion body of different hardness, in which two or more foams of different hardness are integrally foam-molded from two or more liquid foaming raw materials injected into a mold, , a reinforcing sheet made of a foam mainly having continuous pores is installed, a liquid foaming raw material is injected into a predetermined part of the cavity, and a low-hardness foam having the reinforcing sheet integrally is formed by foaming, [2] Thereafter, a series of impregnated reinforcement is installed in the upper part of the cavity adjacent to the low-hardness foam and in the cavity on the reinforcing sheet of the low-hardness foam, and the mold is placed on the reinforcing sheet and adjacent to the low-hardness foam. A method for manufacturing a cushion body of different hardness, characterized by injecting a liquid foaming raw material into a cavity and foam-molding a high hardness foam that is integrated with a low hardness foam and an impregnable reinforcing material. (2) The cushion body of different hardness according to claim 1, wherein the bonding surface of the low hardness foam with the high hardness foam is inclined so as to protrude toward the high hardness foam as it approaches the surface of the low hardness foam. manufacturing method.