JP2557249B2 - Method for manufacturing different hardness cushion body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a cushion body of different hardness having partially different hardnesses.

(Prior Art) In a cushion body that constitutes a seat, for example,
Like the cushion 10 for a seat shown in the figure, a cushion with different hardness in which both side parts 10a are harder than the central part 10b is preferred in order to maintain a sitting posture.

Conventionally, as a simple manufacturing method of the different hardness cushion body, there is the following manufacturing method. FIG. 10 is a cross-sectional view of a mold when manufacturing the different hardness cushion body by the manufacturing method. The mold 12 used has the inside of the cavity divided into a central portion 18a and both side portions 18b by a partition 16 provided upright on the cavity surface 14. In the upper part of the cavity, the central part 18a and the both side parts 18b are in communication with each other. Then, the liquid foam raw material 20a that forms a soft (low hardness) foam is injected into the central portion 18a of the cavity, while the liquid foam raw material 20b that forms a hard (high hardness) foam is injected into both side portions 18b of the cavity. Then, the different hardness cushion body 10 shown in FIG. 9 is integrally foam-molded.

The liquid foaming raw materials 20a and 20b are different in the composition itself, or only different injection ratios (commonly called pack rates) into the cavities using the same composition,
Further, there are cases where both the composition and the injection rate are different.

(Problems to be Solved by the Invention) However, in the above manufacturing method, the central portion 10b
Low hardness foam part (also for low hardness foam part
(Shown by 10b), since the foaming gas released from the liquid foaming raw material or the air in the cavity is chased to the upper part of the cavity during the molding of (10b), the bottom surface 10c of the low-hardness foam whose shape is given by the inner surface of the upper part of the cavity A concave portion formed of a gas reservoir (commonly called an air pocket) is often formed on the back surface (which may be the back surface depending on the application of the different hardness cushion body), and the different hardness cushion body has a desired bottom shape. There is a problem that cannot be obtained.

Further, in a cushion body of different hardness used for a seat or the like, a spring is often provided on the bottom face 10c side for improving cushioning property. In such a case, the spring causes the bottom face 10c of the cushion body of different hardness to be provided. Will be pressed hard. Therefore, if the bottom surface 10c has an irregular concave shape or the like formed of the air pockets, the strength of the bottom surface 10c is reduced at that portion, and there is a problem that damage is likely to occur and durability is reduced.

Further, in the different hardness cushion body obtained by the above manufacturing method, the bottom surface of the low hardness foam also has low rigidity. Therefore, when a load (body weight) is applied to almost the center of the surface of the low-hardness foam, the load cannot be supported by the entire bottom surface, and only the part to which the load is applied is largely bent.

As a result, only the part to which the load is applied bends significantly,
Since the compression deformation of the spring supporting the bottom surface of that portion becomes large, a large elastic repulsive force is generated in the spring. Since the bottom surface of the low-hardness foam is strongly pressed by the large elastic repulsive force, there is a problem that a bottom-pushing feeling occurs and the cushioning property deteriorates.

In addition, depending on the shape of the different hardness cushion body, the thickness of the joint between the low hardness foam and the high hardness foam may not be sufficient. In such a case, the joint area will be small and the joint strength may be insufficient. Therefore, there is a problem that the low hardness foam and the high hardness foam are easily separated at the joint.

On the other hand, the different hardness cushion body is covered with an outer skin and provided for a seat or the like. At that time, in order to prevent wrinkles from being generated on the epidermis, the epidermis is applied to the surface of the different hardness cushion body while pulling the epidermis. However, the different hardness cushion body 10 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 provided upright on the mold cavity surface. Corners 24 are formed on the surface. As a result, since the soft corners 24 are compressed and deformed when the epidermis is attached, there is a problem that the product shape collapses or wrinkles occur on the epidermis.

The present invention has been made in view of the above points, and (i) an object thereof is to provide a cushioning body of different hardness which does not have an irregular shape composed of air pockets on the bottom surface and has high rigidity on the bottom surface. In addition to (i), it is an object of the present invention to provide a cushioning body of different hardness, which has a high bonding strength between a low hardness foam and a high hardness foam and which does not easily lose its shape when the skin is attached.

(Means for Solving the Problem) The present invention provides a method for producing a cushion pad of different hardness, in which two or more liquid foaming raw materials injected into a mold are integrally foam-molded with two or more foams having different hardness, A reinforcing sheet made of foam mainly having continuous air holes is installed on the inner surface of a predetermined portion of the mold cavity, and a liquid foaming raw material is injected into the predetermined portion of the cavity to form a low-hardness foam having a reinforcing sheet integrally by foaming. A body is formed, and then a series of impregnable reinforcing materials is installed in the upper part of the cavity adjacent to the low-hardness foam and the cavity on the reinforcing sheet of the low-hardness foam to form a body on the reinforcing sheet and the low-hardness foam. By injecting the liquid foaming raw material into the mold cavity adjacent to the body and foam-molding the low hardness foam and the high hardness foam integrated with the impregnable reinforcing material, the above object (i) is obtained. It is something to achieve.

Further, in the above-mentioned solution means, the joint surface of the low-hardness foam to be joined with the high-hardness foam is inclined so as to protrude toward the high-hardness foam side as the surface of the low-hardness foam approaches the surface. ii) was achieved.

(Function) First, the liquid foaming raw material injected into a predetermined portion of the cavity fills the cavity by foaming, and impregnates the reinforcing sheet made of foam mainly having communication holes, which is provided on the inner surface of the upper portion of the predetermined portion of the cavity. Then, a low-hardness foam having the reinforcing sheet integrally on the bottom surface is formed. At that time, the foaming gas generated from the liquid foaming raw material and the gas already existing in the cavity are driven to the upper part of the cavity due to the volume increase of the liquid foaming raw material. Since such a reinforcing sheet is provided, it penetrates into the reinforcing sheet and is dispersed in the reinforcing sheet. Therefore, the bottom surface of the low-hardness foam is not affected by foaming gas or the like, and irregular recesses composed of air pockets are not formed.

Further, the liquid foaming raw material impregnated in the reinforcing sheet is prevented from free foaming due to the network skeleton of the foam constituting the reinforcing sheet, and is cured in the reinforcing sheet even in a low foaming state. Therefore, the reinforcing sheet after the liquid foaming raw material is impregnated and hardened is extremely hard, and the low hardness foam having the reinforcing sheet integrally on the bottom surface has a high rigidity on the bottom surface.

Next, a series of impregnable reinforcements is installed on the upper part of the cavity adjacent to the low hardness foam and on the upper part of the cavid on the reinforcement sheet of the low hardness foam, and on the reinforcement sheet and adjacent to the low hardness foam. The liquid foaming raw material is injected into the cavity. The liquid foaming raw material injected onto the reinforcing sheet of the low hardness foam is impregnated into the reinforcing sheet and the impregnating reinforcing material in the upper part of the cavity, and the reinforcing sheet and the impregnating reinforcing material are integrally foamed and cured. But the foam is
The reinforcing sheet is further hardened because it is limited by the net-like skeleton forming the reinforcing sheet and the fibers forming the impregnating reinforcing material and hardly foams, and the impregnating reinforcing material also becomes hard. Therefore, on the bottom surface of the low hardness foam, the hard reinforcing sheet after the liquid foaming raw material is impregnated and hardened and the impregnable reinforcing material are integrally laminated. Further, the liquid foaming raw material injected into the cavity adjacent to the low-hardness foam fills the cavity by foaming, is bonded to the adjacent low-hardness foam, and is impregnated into the impregnable reinforcing material at the upper part of the cavity, Foaming is limited and cured within the impregnable reinforcement to a low hardness foam and a high hardness foam integrated with the impregnable reinforcement. The impregnable reinforcing material on the bottom surface of the high hardness foam (the back surface depending on the application of the different hardness cushion. The same applies below) is extremely hard because the impregnated liquid foaming raw material is cured in a low foaming state. The rigidity and strength of the bottom surface of the high hardness foam are increased. Moreover, since the impregnable 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 coupled and bonded. further,
The foaming gas generated during the molding of the high-hardness foam and the air in the cavity infiltrate and disperse in the impregnating reinforcing material in the same manner as the above-mentioned reinforcing sheet. , An irregular concave shape composed of air pockets is not formed.

The foam integrally formed in this way is soft in the low-hardness foam portion and hard in the high-hardness foam portion, so that it is a cushion body of different hardness having different hardness partially. Moreover, in the low hardness foam portion, the reinforcing sheet hardened by the impregnation and hardening of the liquid foaming raw material and the impregnable reinforcing material are present in two layers on the bottom surface, so that the rigidity of the bottom surface is extremely high.

On the other hand, in the above low hardness foam, when the joint surface with the high hardness foam is formed so as to be inclined so as to protrude toward the high hardness foam side as it approaches the surface of the low hardness foam, the following effects are obtained.

In the obtained different hardness cushion body, the bonding area of the low hardness foam and the high hardness foam becomes large due to the inclination of the bonding surface, so that the bonding strength becomes high.

Further, due to the inclination of the joint surface, in the low-hardness foam portion around the joint, the high-hardness foam is covered with the low-hardness foam, so that the surface of the low-hardness foam around the joint is Hardened by the high hardness foam inside. As a result, when the surface of the low hardness foam is pressed by the tension of the skin when the surface of the different hardness cushion is covered with the skin, even if the surface of the low hardness foam is pressed by the tension of the skin, Wrinkles are less likely to occur.

(Examples) Examples will be described below with reference to the drawings. 1 to 3 are cross-sectional views of a mold showing the production of the cushioning body for different hardness in one embodiment of the present invention, FIG.
The figure shows the different hardness cushion body 26 for the seat manufactured by it.
FIG.

First, the seat cushion cushion 26 of FIG. 4 will be described. The different-hardness cushion body 26 for a seat constitutes a seat portion of a vehicle seat, and in order to maintain an occupant's posture when the vehicle rotates, a low-hardness foam body 28 is formed in a central portion and high-hardness foam bodies 30 are formed on both sides. Consists of. A reinforcing sheet 32 is integrated with the bottom surface of the low hardness foam 28, and an impregnating 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 obtained by impregnating and hardening the liquid foaming raw material forming the low hardness foam 28, and the impregnable reinforcing material 34 is also impregnating and hardening the liquid foaming raw material forming the high hardness foam 30. It is hardened.

The hardness of the low hardness foam 28 and the high hardness foam 30 is appropriately determined depending on the application of the different hardness cushion body. Further, the terms "low hardness" and "high hardness" in this specification are used in a relative meaning and do not indicate an absolute meaning, and one is more desirable than the other to a desired degree. soft"
Or, it means "hard".

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

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. On the upper mold 38a cavity surface, a foam mainly composed of continuous air holes, for example, a reinforcing sheet 32 made of a soft polyurethane foam is installed by using pins (not shown) standing on the upper mold cavity surface and the like, A liquid foaming material 28a such as a polyurethane material is injected into the cavity 36 and foaming is performed in a closed mold. The liquid foaming raw material 28a injected into the cavity 36 is the cavity 3 due to the foaming reaction.
After filling with 6, the reinforcing sheet 32 on the cavity surface of the upper die is impregnated to form a low hardness foam having the reinforcing sheet 32 integrally on the bottom surface. At that time, the liquid foaming raw material impregnated in the reinforcing sheet 32 is limited in foaming due to the network skeleton of the foam constituting the reinforcing sheet, and is cured in the reinforcing sheet 32 in a low foaming state, so that the impregnation after curing The reinforcing sheet becomes extremely hard.

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

The mold 44 has a cavity 46a for accommodating the low-hardness foam 28 inside and a cavity 46b for forming a high-hardness foam on both sides thereof. Further, on the cavity surface of the lower mold 44b, a partition 48 for fixing the position of the low hardness foam 28 is provided at the upper part of the cavity at the boundary between the low hardness foam housing cavity 46a and the high hardness foam forming cavity 46b. It is provided to leave.

In the low-hardness foam accommodating cavity 46a, the low-hardness foam 28 taken out from the mold 38 is installed with the reinforcing sheet 32 side facing up, and the impregnating reinforcing material 34 is placed on the cavity surface of the upper mold 44b.
With a pin or the like standing on the cavity surface.
The impregnating reinforcing material 34 is made of a material for impregnating a liquid foaming material such as coarse wool felt and cotton cloth, and has a low hardness foam accommodating cavity.
46a and the high-hardness foam forming cavity 46b are continuously installed on the upper part. And the low hardness foam reinforcing sheet
A liquid foaming raw material 30a such as a polyurethane foam raw material is injected into the upper and high-hardness foam forming cavity 46a and the mold is closed.

The liquid foaming raw material 30a injected onto the reinforcing sheet 32 is impregnated into the reinforcing sheet 32 and the impregnable reinforcing material 34 to form a reinforcing sheet.
Foaming is restricted by the mesh-like skeleton constituting 32, the fibers constituting the impregnable reinforcing material 34, etc., and the reaction is cured with almost no foaming, and the hardened impregnable reinforcing material 34 is bonded to the reinforcing sheet 32. To do. Further, the liquid foaming raw material injected into the high-hardness foam forming cavity 46b fills the cavity 46 by the foaming reaction, adheres to the low-hardness foam 28 in the gap portion above the partition 48, and impregnates the upper portion of the cavity. High hardness with impregnating reinforcing material 34 integrally impregnated on the bottom surface by impregnating the reinforcing material 34, foaming is limited in the impregnating reinforcing material 34 in the same manner as described above, and reaction hardening occurs in a low foaming state. Become a foam.

After that, if the molded product is taken out from the mold 44, the different hardness cushion body 26 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.
Alternatively, the same composition may be injected by increasing the pack rate to the cavity. Further, the mold for forming the low hardness foam and the mold for forming the high hardness foam may be common, and FIG. 3 is a sectional view of the common mold 50. This mold 50 has a structure similar to that of the molds 38 and 44 except that the insert 52 is fitted when the low hardness foam is formed as shown in this figure and the insert 52 is removed when the high hardness foam is formed. By using this mold 50, it is possible to continuously perform the manufacturing operation without moving the low hardness foam from one mold to another.

On the other hand, FIG. 5 and FIG. 6 are sectional views of a mold showing another embodiment at the time of manufacturing, and FIG. 7 is a sectional view of the seat different-hardness cushion body 54 obtained by the manufacturing.

The different-hardness cushion body 54 has a joint surface 60 of a low-hardness foam body 56 and a high-hardness foam body 58 that is inclined, and protrudes toward the high-hardness foam body 58 as it approaches the surface. It has the same configuration as.

Similar to the different hardness cushion body 26, the different hardness cushion body 54 has a high rigidity at the bottom surface, and the surface of the low hardness foam around the joint with the high hardness foam is affected by the high hardness foam inside. It has become harder.

The different hardness cushion body 54 is manufactured by the mold shown in FIG.
Since the low hardness foam body 56 is formed by using 62, it is performed in the same manner as in the production of the different hardness cushion body 26, and therefore only the essential points will be described below.

The mold 62 is an upper mold that forms the bonding surface 60 of the low hardness foam.
Both side surfaces 64a of the cavity of 62a are inclined, and the cavity 64 expands downward.

A low-hardness foam body having a reinforcing sheet 32 on the cavity surface of the upper mold 62a of the mold 62, and injecting a liquid foaming raw material 56a to cause a foaming reaction to impregnate and harden the liquid foaming raw material into a hard reinforcing sheet 32 on the bottom surface. Forming 56. The formed low-hardness foam 56 has a joint surface 60 with the high-hardness foam that protrudes toward the high-hardness foam as the surface 60 of the low-hardness foam approaches the surface of the low-hardness foam.

It should be noted that the mold 38 shown in FIG. 1 is used to form the low-hardness foam body 28 whose both side surfaces to be joined are not inclined, and the both sides are subjected to post-processing such as cutting to form an inclined joint surface 60. May be formed.

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

Then, the impregnating reinforcing material 34 is installed on the entire upper mold cavity surface, the liquid foaming raw material 58a is injected into the cavity 46b and on the reinforcing sheet 32, and the low hardness foam 56 and the impregnating reinforcing material hardened by the impregnation curing. A high hardness foam 58 integral with 34 is formed. Then, if the molded product is taken out from the mold 44, the different hardness cushion body 54 of FIG. 7 is obtained.

Further, FIG. 8 is obtained by another embodiment of the present invention,
FIG. 6 is a vertical cross-sectional view of a different hardness cushion body 68 for a seat back. In the figure, 70 indicates a low hardness foam and 72 indicates a high hardness foam.

(Effect) Since the present invention has the above-mentioned configuration, the following effects can be obtained.

First, since a cushion body with a different hardness with a high bottom surface is obtained, the load is supported by the entire bottom surface when it is used for a seat, etc., and part of it does not bend significantly, so it is difficult for the bottom to feel. There is an effect.

Further, since the irregular recesses formed by the air pockets are not formed on the bottom surface of the different hardness cushion body, the strength of the bottom surface does not become partially weak, and even if a spring is arranged on the bottom surface, the bottom surface may be damaged. There is an effect that durability is improved. Further, there is an effect that a desired shape can be obtained without irregular recesses or the like on the bottom surface.

Further, in the case where the joint surface of the low hardness foam with the high hardness foam is inclined so as to protrude toward the high hardness foam side as it gets closer to the surface, the following effect is obtained in addition to the above effect.

First, the bonding area between the low-hardness foam and the high-hardness foam in the different-hardness cushion body is large, so that the bonding strength is high and the low-hardness foam and the high-hardness foam are difficult to separate. .

Further, since the surface hardness of the low hardness foam around the joint with the high hardness foam becomes high, the tension of the skin when applying the skin to the different hardness cushion body causes the surface tension of the low hardness foam (corner part). ), The surface is less likely to be deformed, the shape is less likely to be deformed, and wrinkles on the epidermis are less likely to occur.

[Brief description of drawings]

1 to 3 are cross-sectional views of a mold when manufacturing a different hardness cushion body according to the present invention, and FIG. 4 is a cross-sectional view of the different hardness cushion body obtained by carrying out the present invention, FIG. FIG. 6 is a sectional view of a mold at the time of manufacturing the different hardness cushion body in another embodiment of the present invention, and FIGS. 7 and 8 are sectional views of other different hardness cushion bodies manufactured by the present invention. FIG. 9 is a sectional view of a different hardness cushion body obtained by a conventional manufacturing method, and FIG. 10 is a sectional view of a mold at the time of manufacturing a different hardness cushion body by the conventional manufacturing method. 28,56: Low hardness foam, 28a, 30a: Liquid foaming raw material, 30,58: High hardness foam, 32: Reinforcing sheet, 34: Impregnable reinforcing material, 38, 44, 62: Mold, 60: Bonding surface

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 31:58

Claims (2)

(57) [Claims] 1. A method for producing a cushioning body of different hardness, which comprises integrally foam-forming two or more foams having different hardnesses from two or more liquid foaming raw materials injected into a mold, wherein A reinforcing sheet composed of a foam mainly having continuous air holes is installed, and a liquid foaming raw material is injected into a predetermined portion of the cavity to form a low hardness foam integrally having a reinforcing sheet by foaming, and then the above low hardness. A series of impregnating reinforcing materials is installed in the upper part of the cavity adjacent to the foam and in the cavity on the reinforcing sheet of the low-hardness foam, and the liquid is formed on the reinforcing sheet and in the mold cavity adjacent to the low-hardness foam. A method of manufacturing a cushion body of different hardness, which comprises injecting a foaming raw material and foam-molding a low hardness foam and a high hardness foam integrated with an impregnable reinforcing material. 2. The different hardness according to claim 1, wherein a joint surface of the low hardness foam with the high hardness foam is inclined so as to protrude toward the high hardness foam side as the surface approaches the low hardness foam. Cushion body manufacturing method.