JPH03261410A - Molding method for polyurethane sheet pad - Google Patents

Abstract

PURPOSE:To obtain the sheet pad in which the inside part for touching the thigh of a bank part and the top part are soft and which is comfortable to sit on by providing a liquid reservoir container of a foam polypropylene or foam polyethylene in a side part of a cavity, injecting a foaming stock solution for a low hardness foaming body into the cavity, and injecting a foaming stock solution for a high hardness foaming body into the liquid reservoir container. CONSTITUTION:In a cavity 1, in each side part 3, 3 of a foam molding mold 4 having a center part 2 corresponding to a seat part of a seat pad and side parts 3, 3 corresponding to a bank part, liquid reservoir containers 5, 5 consisting of foam polypropylene or foam polyethylene are attached, respectively in a stage that they are separated from the lowest face of these side parts 3, 3. In the cavity between the liquid reservoir containers 5, 5, a foaming stock solution for a low hardness foaming body is injected, and also, in the liquid reservoir containers 5, 5, a foaming stock solution for a high hardness foaming body is injected and foaming is executed. A hard part and a soft part are formed integrally and satisfactorily, a boundary between different quality parts is formed clearly and stably, and also, it is comfortable to sit on, and a bank part different hardness polyurethane sheet pad for displaying satisfactorily a characteristic of a foaming raw material can be manufactured surely.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for forming a polyurethane seat pad used for automobile seats, etc.
The present invention relates to a method of molding a polyurethane seat pad in which bank portions having a different hardness than the seat portion are formed on both sides of the seat portion or the peripheral edge thereof.

[Problems to be solved by conventional techniques and inventions] In recent years,
As a manufacturing method for seats for automobiles, etc., a method is often used in which a polyurethane seat pad (stuffing) with banks on both sides of the seat is covered with a skin material.In this case, the entire polyurethane seat pad is Although those formed with uniform hardness are also used, the hardness of the bank part urethane seat pad, in which the hardness of both bank parts is higher than that of the seat part, improves support for the body and improves the appearance of the upholstery of the skin material. It is preferably used in this respect.

Conventionally, the method shown in FIGS. 13 and 14 is known as a method for manufacturing the above-mentioned bank part hardness polyurethane sheet pad. That is, in the method shown in FIG. 13, a weir plate d is provided protruding from the mold a at the boundary between the center part corresponding to the seat part of the cavity and the side parts c, c corresponding to the bank part. A is a foaming raw material for obtaining a foam with low hardness.
In this method, liquid B, which is a foaming raw material for obtaining a highly hard foam, is injected into both side parts c and c, respectively, and these are foamed. In addition, the method shown in FIG. 14 is such that metal partition plates e, e are integrally protruded from the bottoms of both side parts C, C in the mold a of FIG. 13, or partitions made of foamed resin are provided. Plates e and e are placed, and A is placed inside these partition plates e and e.
In this method, foaming is performed by injecting liquid and liquid B into the outside.If a metal partition plate is provided, this partition plate is removed from the pad after foaming, and a partition plate made of foamed resin is used. If it breaks, this partition plate will stick to the polyurethane foam and remain on the pad.

However, each of the above-described conventional methods of manufacturing hardness urethane sheet pads for bank parts has the following drawbacks.

That is, in the pad obtained by the method shown in FIG. 13, the entire bank part f has a high hardness as shown in FIG. 15, so when sitting, the hard bank part f hits the thighs, causing a feeling of discomfort and making the sitting uncomfortable. Not only is this bad, but the bonding surface between the high hardness foam and the low hardness foam is likely to peel off. In addition, the pad obtained by the method shown in FIG. 14 has the removal groove g of the partition plate remaining at the top of the bank part f as shown in FIG. 16, and the pad made of foamed resin as shown in FIG. Because the plate e remains, the seated person will feel the removal groove g and the partition plate e on their thighs, etc., which will cause an uncomfortable feeling and be uncomfortable to sit on. Easy to tear. Furthermore, in the method shown in FIG.
, e and moves to the opposite side, making the boundary between the high-hardness part and the low-hardness part unclear, making the quality unstable, and liquid B also moves to the back side of the pad (No. 16.17). Because there is not enough sag in the part shown in the figure, the support
The tension of the skin material is insufficient, and the timing of injection of liquids A and B is difficult. If the timing is not right, a large amount of one liquid will flow over the partition plates e and e to the other side. Because of this, you can't get pads of the right quality.

In addition, as another manufacturing method for the above-mentioned bank part hard polyurethane sheet pad, a container made of foamed polystyrene is attached to both sides of the mold, and liquid B is poured into this container and liquid A is poured into other parts to form foam. A method has also been proposed in which the container is contracted by external heating or the reaction heat of foaming to integrate the polyurethane foam of liquid A and the polyurethane foam of liquid B (Japanese Patent Laid-Open No. 63-25008).
Publication No.).

According to this manufacturing method, although the above-mentioned problems such as comfort, support, and tension of the skin material can be improved, the following drawbacks remain.

(1) The foaming stock solution usually contains an organic solvent such as methylene chloride as a foaming agent, but in such cases, the foamed polystyrene sheet that makes up the container will be instantly dissolved by this solvent component after the stock solution is poured. There are cases where the foaming stock solution flows out of the container and the purpose of separating stock solutions A and B cannot be fully achieved.

In addition, in this case, even if no liquid leakage occurs, the container becomes extremely soft, making it difficult to maintain the container in a predetermined shape until the end of foaming, and it may not be possible to form a stable seat pad. arise.

Furthermore, when molding a molded article, raw materials are supplied into the mold through a nozzle, and the nozzle is cleaned with an organic solvent such as methylene chloride each time the raw material is supplied. At this time, the container may be damaged by the organic solvent used for cleaning.

(2) Furthermore, in the above method, the expanded polystyrene container is heat-shrinked, but it is preferable that the container after heat-shrinking has flexibility equivalent to that of polyurethane foam. However, when a container is constructed from a foamed polystyrene sheet prepared to have such good flexibility after heat shrinkage, the container has low strength and poor self-support before heat shrinkage, and therefore foaming It is difficult to maintain a predetermined shape during injection of raw materials. On the other hand, if a container is constructed from a foamed polystyrene sheet prepared to provide sufficient self-support during the injection of raw materials, such a container will become extremely hard and brittle after heat shrinkage, making it difficult to flex. Not only will the elasticity and elasticity necessary for the seat pad be lost (,
Cracks or breaks may occur when subjected to large forces or deformations.

The present invention was made in view of the above circumstances, and when manufacturing a bank part hardness polyurethane sheet pad,
We always use a liquid storage container that has the same flexibility and feel as polyurethane foam, and the part of the bank that touches the thigh can be made soft, and the groove for removing the partition plate and the partition plate remain at the top of the bank. I can't let you do it (,
Good sitting comfort can be obtained, and the characteristics of the foamed raw material can be exhibited well, and the hard part and soft part can be well bonded and integrated, and the boundaries between these dissimilar parts can be made to look unnatural (clear). It is an object of the present invention to provide a method for forming a polyurethane sheet pad in a stable manner.

[Means and Effects for Solving the Problems] In order to achieve the above object, the present invention provides a polyurethane seat pad having bank portions on both sides or peripheral portions of a seat portion, and a center portion corresponding to the seat portion and the above. In a method of molding using a foaming mold having side parts corresponding to the bank part, a liquid reservoir made of foamed polypropylene or foamed polyethylene is installed in each side part of the foaming mold, and a liquid reservoir made of foamed polypropylene or foamed polyethylene is installed between these liquid reservoirs. A foaming stock solution for obtaining a foam with low hardness is injected into the cavity of the liquid reservoir, and a foaming stock solution for obtaining a foam with high hardness is injected into the liquid storage container to cause foaming. To provide a method for molding a polyurethane sheet pad, which is characterized in that a polyurethane sheet pad in which a polyurethane sheet pad remains as it is is obtained.

In the present invention, a liquid reservoir made of foamed polypropylene or foamed polyethylene is provided in the side part of the cavity,
Since the foaming solution for low-hardness foam is injected into the cavity between the liquid reservoirs of each side part, and the foaming solution for high-hardness foam is injected into the liquid reservoir, the bottom of the side part A raw solution of low-hardness foam flows into the seat pad, and therefore, the inside and top portions of the bank of the seat pad that touch the thighs are formed of low-hardness foam in the same way as the seat pad, giving a hard feel even when the thighs hit the bank. Never. Further, since the liquid reservoir remains as it is within the bank of the pad and does not remain on the top, the seated person does not feel the remaining container. Furthermore, since the container prevents the two stock solutions from mixing, and the high-hardness part and low-hardness part of the pad are separated by the liquid reservoir, the boundary between the high-hardness part and the low-hardness part is kept at a predetermined position. It is clearly formed and stable in quality. In addition, by using foamed polyethylene or foamed polyethylene as the material for the liquid reservoir, the hard part and the soft part can be well bonded together without the need for heat shrinkage. This combination of flexibility and rigidity allows the seat pad to always have good elasticity without cracking or breaking even when subjected to large forces or deformation. There is nothing that makes you feel uncomfortable. In addition, containers made of these materials are stable against organic solvents such as methylene chloride, and the ingredients of the foaming stock solution are not limited, allowing the use of desired foaming raw materials and improving the characteristics of the foaming raw materials. This can be fully reflected in the product.

Furthermore, by appropriately setting the size, shape, plate thickness, mounting position, etc. of this liquid reservoir, the shape, position, etc. of the boundary line between the high hardness part and the low hardness part can be changed in various ways.
For this reason, the performance of the pad, such as support, can be adjusted arbitrarily without modifying the mold in any way.
By increasing the volume of the liquid storage container, a large amount of the foaming stock solution can be stored in the container, thereby making it possible to reduce the accuracy of injection timing and injection amount of the foaming stock solution.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[Example] First, as shown in Fig. 1.2, the above-mentioned foaming mold 4 has a center part 2 corresponding to the seat part of the seat pad and side parts 3, 3 corresponding to the bank parts in the cavity l. A liquid reservoir 5,5 made of foamed polypropylene or foamed polyethylene is installed in each side portion 3.3, spaced apart from the lowest surface of these side portions 3.3. In addition, 6, 6 shows the weir plate provided protrudingly at the boundary between the center part 2 and the side parts 3, 3. In this case, the foam molding mold may have side parts 3, 3 on both sides of the center part 2 facing each other as shown in FIG. In addition to both sides, it is also possible to use a mold having two opposite side parts, in which case a liquid reservoir can also be attached to the other two side parts. Alternatively, as shown in FIG. 3, a closed mold 4 consisting of an upper mold 4a and a lower mold 4b may be used, and the containers 5, 5 may be attached to the upper mold 4a.

Here, the shape of the liquid reservoir 5 is not particularly limited, but it is preferable to use one having an arched bottom. That is, the seat pad 7 is formed using a hollow hemispherical container 5 with an arched bottom as shown in FIG. 4, and the seat pad 7 is formed using a container 5 with a flat bottom as shown in FIG. When compared with the case where the boundary layer 8 is molded, even if the width and volume of the boundary layer 8 are the same, the one shown in FIG. 4 has a stronger resistance to external force F than the one shown in FIG. 5, and therefore has higher supportability.

As this liquid reservoir container, it is preferable to use a container in which the liquid reservoir part 5a and the mounting part 5b are connected in series like the container shown in FIGS. Although it can be easily attached to the outside wall, Fig. 6 (A),
As shown in (B), a container consisting only of a liquid reservoir 5a or a small container with pieces 5c connected to the liquid reservoir 5a can be attached to the inside of a mold using pins or the like. That is, FIG. 7(A).

As shown in (B), one side of the liquid reservoir 5 is attached to the pins 3a, 3a, 3a on the outer wall of the side portion 3 of the mold 4, and the attachment is on the side 5C of the mold 4. The container 5 can be attached to a pin 6a protruding from the weir plate 6, or a support rod 3b can be placed in the center of the side part 3 as shown in FIG. However, the container 5 can be attached in the mold by attaching the liquid reservoir 5a to the pin 3C protruding from the tip of the support rod 3b.

Furthermore, in this case, when the mounting piece 5C is provided, this mounting piece 5C can be attached to the pin 6a of the weir plate 6 in the same manner as shown in FIG.

In addition, as shown in FIG. 9, the container 5 having both the mounting part 5b and the mounting piece 5C is used, and the mounting part 5b is attached to the spigot part (grinding part) 4c of the closed mold 4. The container 5 can also be disposed within the side portion 3 by attaching the piece 5C to a pin 3d provided on the weir plate 6. In this case, since the container 5 is made of foamed polypropylene or foamed polyethylene, which has excellent flexibility, the attachment is performed at the portion 5b.
Even if it gets caught in the inlet part 4C of the mold, the sealing performance of the closed mold will not be impaired.

When this container is attached, the container 5 can be arranged at a distance from the outer wall of the side part 3, so that the container 5 does not appear on the outer surface of the pad 7, as shown in FIG. 1O. However, at this time, the container 5 may shift laterally or
In order to prevent this from coming into contact with the outer wall, a support rod 9a or a support piece 9b can be provided within the side portion 3, as shown in FIG. 7(B). In addition, the above installation is done using pin 3a,
Since the supporting rods 6a, the supporting rods 9a, and the supporting pieces 9b are needle-shaped or thin rod-shaped, they do not form large holes or grooves that would impair sitting comfort.

Furthermore, the container 5 includes a liquid reservoir 5 as shown in FIG.
The width l of a is 20 to 100% of the total width of the side part, especially 40%
~80%, depth m is 10~100% of the total depth of the side part
, especially 30-80%, plate thickness 1-6 mm, especially 1
A thickness of ~4 mm is preferable, and this can improve support properties. The mounting position of the container 5 is determined by setting the distance n between the bottom of the side part 3 and the lower end of the container 5 from 0 to
6 cm, particularly 1 to 6 cm, more preferably 2 to 6 cm, from the viewpoint of support.

Further, it is preferable that the volume of the container is 0.8 to 2.51, thereby making it possible to ease the injection timing and injection amount precision of the foaming stock solution and improve productivity. Furthermore,
The inner and outer surfaces of the container can also be textured to increase the surface area and improve the adhesive strength with the urethane foam.

Next, a foaming stock solution for low-hardness foams (hereinafter referred to as "Liquid A") is injected into the cavity between the liquid reservoirs 5, 5, and a foaming stock solution for high-hardness foams (hereinafter referred to as "Liquid B") is poured into the liquid reservoirs 5, 5. (referred to as liquid) is injected to cause foaming.

In this case, the A liquid may be made to flow from above the weir plate 6 to the center part 2 and the side parts 3 as shown in FIG. 11, or separately to the center part 2 and the side parts 3 as shown in FIG. It may also be injected into the

In addition, as the foaming stock solution, those with known compositions as foaming raw materials for soft, semi-rigid, and rigid polyurethane foams can be used, and those containing organic solvents such as methylene chloride as a foaming agent can also be suitably used, but especially Liquid A has a hardness of lO~20kg/φ200 as measured by a push-pull gauge (manufactured by Aiko Engineering Co., Ltd.) after foaming.
It is desirable to use liquid B having a hardness of 1.8 to 4 kg/φ200 after foaming, which can improve support properties.

In this way, the liquid reservoir container 5 made of foamed polypropylene or foamed polyethylene is arranged inside the side parts 3, 3 of the foam mold 4, and the B liquid is placed in the container 5, and the A liquid is placed in the cavity 1 other than the container 5. By injecting them and foaming them, the hard and soft parts are well integrated, the boundaries between these different parts are clearly and stably formed, and the seating comfort is good. It is possible to reliably produce a polyurethane sheet pad with different hardness at bank portions that exhibits excellent characteristics.

That is, according to the above manufacturing method, liquid A for low-hardness foam flows into the bottom of the side part 3 of the mold 4, and the inner part and the top part of the bank part of the seat pad, which contact the thighs, become low like the seat part. Since it is made of hard foam, it does not give a hard feeling even when the thigh hits the bank, and since the container 5 remains within the bank of the pad and does not remain on the top, the seated person can feel the remaining container. Furthermore, the container 5 prevents the foaming raw materials A and B from mixing, and the container 5 reliably separates the high hardness part and the low hardness part of the pad so that the boundary between the two hardness parts is maintained. is clearly formed in a predetermined position, and the quality is stable. Moreover, since the container 5 is made of foamed polypropylene or foamed polyethylene, the container 5 is not subject to heat shrinkage (the high hardness portion and the low hardness portion are well bonded and integrated, and the container 5 has a suitable rigidity). Since the container 5 has both good elasticity and flexibility, it does not crack or break even when subjected to large force or deformation, and can always provide good elasticity to the bank of the seat pad. is stable even in organic solvents, and there are no restrictions on the ingredients of the foaming stock solution. Further, when the container 5 is made of foamed polyethylene, in addition to the above-mentioned effects, it is also advantageous in terms of cost compared to the conventional manufacturing method using a container made of foamed polystyrene.

Note that the method for forming a polyurethane sheet pad of the present invention is not limited to the above embodiment. For example, in the above embodiment, one liquid reservoir was provided on each side, but if necessary, one liquid reservoir was provided on each side. Two or more liquid reservoirs are provided in each section, and the same foaming stock solution or foaming stock solutions with different characteristics can be injected into these plurality of liquid storage containers. The shape of the mold and the like may be changed in various ways within the scope of the gist of the present invention.

[Effect of the invention] As explained above, the present invention has the following effects.

■The inside part and top part of the bank part that corresponds to the thighs are soft, making it possible to obtain a seat pad that is comfortable to sit on.

■It is possible to obtain a seat pad that does not make the occupant feel uncomfortable due to the remaining liquid reservoir.

■Since it is possible to prevent the high-hardness foam stock solution and the low-hardness foam stock solution from mixing with each other, the boundary between the high-hardness part and the low-hardness part can be clearly defined and stably formed in a predetermined position. Therefore, a seat pad of stable quality can be obtained.

(2) A seat pad in which the high hardness part and the low hardness part are well bonded together can be obtained.

■By appropriately setting the shape, size, plate thickness, and mounting position of the liquid reservoir, the performance of the seat pad, such as its support properties, can be adjusted as desired.

(2) By increasing the volume of the liquid reservoir, the accuracy of injection timing and injection amount of the foaming stock solution can be relaxed, and therefore productivity can be improved.

(2) The above adjustments (2) and (2) can be easily made by simply changing the shape of the container without modifying the mold in any way.

■By hardening the pad side edge, the outline of the pad becomes clear and the appearance of the seat skin is improved.

(2) The ingredients of the foaming raw material are not limited, and any desired raw material can be used, and the characteristics of the foaming raw material injected into the liquid reservoir can be well reflected in the product.

[Phase] The liquid reservoir does not easily crack or bend, and stable elasticity and good seating comfort can be reliably obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a mold used for carrying out the present invention, FIG. 2 is a plan view of the same mold, FIG. 3 is a cross-sectional view showing another example of the mold, and FIGS. 5 is a partially omitted sectional view showing the seat pad obtained by the present invention, and FIG.
Figures (A) and (B) are perspective views showing other examples of the container, and Figures 7 (A) and (B) to Figure 9 each show the manner in which the liquid reservoir container is attached. (A) is a partial plan view, 7th
Figure (B) is a cross-sectional view taken along the line B-B of Figure 7 (A), Figures 8 and 9 are cross-sectional views showing other mounting modes, and Figure 10 is a cross-sectional view of the other pads. A sectional view showing an example, FIGS. 11 and 12 are explanatory views showing the state in which the foaming stock solution is injected in the present invention, FIGS. 13 and 14 are explanatory views showing the conventional molding method, respectively, and FIGS. FIG. 17 is a partially omitted sectional view showing a seat pad obtained by a conventional method. DESCRIPTION OF SYMBOLS 1... Cavity, 2... Center part, 3... Side part, 4... Foaming mold, 5... Liquid reservoir container. Figure 1

Claims (1)

[Claims] 1. In a method of molding a polyurethane seat pad having bank parts on both sides or the peripheral edge of the seat part into a cavity using a foaming mold having a center part corresponding to the seat part and side parts corresponding to the bank parts. , a liquid reservoir made of foamed polypropylene or foamed polyethylene is installed in each side part of the foam mold, and a foaming stock solution for obtaining a low hardness foam is injected into the cavity between these liquid reservoirs, and the above-mentioned A polyurethane sheet pad characterized in that a foaming stock solution for obtaining a highly hard foam is injected into a liquid storage container and foaming is performed to obtain a polyurethane sheet pad in which the liquid storage container remains as it is inside. Molding method.