JPH0722932B2 - Seat cushion and method of molding the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a seat cushion that provides a good seating feeling in a thin seat cushion and a method for manufacturing the seat cushion.

[Conventional technology]

A conventional seat cushion system having an intermediate layer has the following configuration.

(A) Japanese Utility Model Publication No. 48-32108 (name of device, sheet-shaped cushion) This device has a sheet-shaped cushion made of a soft synthetic resin foam having a density of 0.025 to 0.03 as described in the claims. The member 1, the pad member 2 made of a synthetic resin foam having a density of at least 0.04 or more, which is surrounded by one side of the cushion member, and is rigid and porous between the cushion member and the pad member. The sheet-like cushion integrally formed by interposing the sheet-like partitioning member 3 having a sufficient flexibility. "
Is a sheet-like material having a certain degree of rigidity and being porous and having sufficient flexibility, for example, a rough cloth woven from synthetic fibers or a mesh formed from synthetic resin. It is explained that there is.

Further, the method of integral molding and the shape of the molded body are described as follows.

"The expandable synthetic resin stock solution that forms the semi-rigid pad member 2 is poured into a mold having the shape of the target product, and the partition member 3 is placed on the liquid surface where the foaming liquid is foaming. By injecting the expandable synthetic resin stock solution for forming the soft cushion member 1 onto them, these three parts can be easily obtained as a molded product integrally bonded. The cushion not only effectively supports a vertical load, but also when used as a cushion for an automobile, it relatively surrounds the periphery of the cushion member 1 against rolling due to horizontal vibration of the vehicle body. The high-density pad member 2 can exert an effective action force for reducing the rolling. ”As described above, the sheet-like cushion described here is in the middle of natural foaming of the soft cushion member. At
A seat cushion with a shape in which a rigid partition member is covered, and the entire circumference of the side surface and bottom surface is embedded with a pad member with a density of 0.04 or more. A member is placed on the partition member, and the partition member is pushed up by the foaming force to foam.

(B) Japanese Utility Model Laid-Open No. 57-351 (name of device, cushion structure of seat) This cushion structure has a structure in which a pad material formed in a predetermined shape is placed on the bottom plate as described in the claims. Then
In a cushion formed by covering this with an outer skin, the lower pad is made harder than the upper pad by using the pad material as upper and lower two layers, and the interface between the upper pad and the lower pad is formed into a shape corresponding to the body shape of the seated person, A cushion structure for a seat, wherein a hardened layer is formed on a boundary surface between the upper pad and the lower pad. According to the detailed description of the invention, the hardened layer is a tough hardened layer obtained by impregnating and hardening a rigid fiber material such as coarse wool felt with an undiluted urethane solution. ,
By laying a rigid fiber material such as coarse wool felt on the bottom surface of the foaming mold of the upper layer pad 21, and injecting a urethane undiluted solution to integrally foam it, the upper layer pad 21 backed by a tough cured layer is molded, and this upper layer pad 21 And the lower layer pad 22 formed by another mold are overlapped to form the pad material 2,
Then, the end edge is fixed to the bottom plate 1 by an appropriate method such as hog ring. As a result, the upper layer pad 21 and the lower layer pad 22 are firmly attached to the bottom plate 1 without being displaced from each other.

As described above, also in the present invention, as in (a), the intermediate layer of the tough cured layer is formed by impregnating the rigid fiber material with the urethane stock solution. Further, it is not an integral structure, but a structure in which an upper layer pad and a lower layer pad formed by different molds are superposed.

[Problems to be solved by the invention]

In the above-mentioned conventional technique, the structure (a) has a structure in which a cushioning member is restrained by a partition member having rigidity such as a woven fabric of synthetic fibers or a mesh of synthetic resin. It is a composite with a very deformable foam, and due to the combination of the difference in physical properties between the minimum elongation and the maximum elongation, the two physical discomforts do not work at the moment the cushion stress is applied. It gives a harmonious seating feeling, and such a feeling of discomfort is particularly serious in a thin seat cushion. In addition, breakage due to cushion operation at the interface between the rigid body and the foam is significantly promoted.

Further, since the partition member is formed in a naturally foamed state, the partition member is in an irregular state, so that the high-density pad member cannot obtain a constant shape and the thickness is also irregular. Further, since the thickness of the soft upper pad is naturally irregular, the uncomfortable seating feeling that gives the above-mentioned uncomfortable feeling is further increased.

Further, in the configuration of the prior art of (b), a rigid fiber material such as coarse wool felt is laid on the lower surface of the mold for the upper layer pad, and the urethane raw solution is impregnated with the rigid fiber material by a method of injecting urethane undiluted solution and integrally foaming. A toughened hardened layer is formed by stacking the upper layered pad lined with this toughened hardened layer and a lower layered pad molded with a separate mold, and then fixed by embracing them in the skin, so a certain shape can be obtained. Similar to (a), the hardened layer consists of a rigid fibrous material and an intermediate layer of a toughened hardened layer impregnated with a urethane stock solution. It has similar drawbacks such as giving a feeling of feeling and bottoming out.

Further, since the upper layer pad and the lower layer pad are formed by separately molding with different molds, the shrinkage allowance of the lower surface of the upper layer pad which is integrally foamed by laying a rigid fiber material on the lower surface of the foam, Unlike the shrinkage allowance of the upper surface of the foam of the upper pad that is foam-molded in a separate mold, it is not only difficult to obtain the dimensional accuracy of the fitting part of the stacking portion of the upper surface of the lower pad and the lower surface of the upper pad, but also during cushioning. In the meantime, a sliding friction phenomenon occurs, and the durability is greatly reduced due to the slip on the foam.

Therefore, the object of the present invention is to eliminate the molding method such as the prior art of the above (a) in which a constant shape cannot be obtained, and to form an intermediate layer of various required shapes as designed in the same mold. It is an object of the present invention to provide a seat cushion which can be formed, and which has an intermediate layer accurately and wholly and partly at a desired position, and which has a good cushioning property and a comfortable seating feeling even if it is thin.

The molding method that inserts the intermediate layer partially accurately
This is a molding method in which the intermediate layer is accurately put into various shapes at a partial position of the interface between the upper and lower two layers, particularly at an intermediate partial position which is not continuous with the side wall, and its solution has been particularly desired conventionally.

[Means for solving problems]

According to the present invention, the intermediate layer of the elastic support member having a required shape integrally foam-molded on one surface of the flexible low-density foam and the flexible high-density foam are integrally laminated in the required shape with the same mold. Relates to a seat cushion.

That is, in the present invention, an elastic support suitable for cushioning impact force is used for an intermediate layer of a laminate composed of a soft low-density foam and a soft high-density foam, and this is molded at a desired position as designed. By integrally forming and arranging into a desired shape, the discomfort is resolved, and a comfortable seating feeling with good cushioning is obtained.

As the elastic support used in this intermediate layer, natural rubber, synthetic rubber, polyurethane or other polymeric substance having rubber-like elasticity at room temperature, that is, a fiber member or sheet member mainly composed of an elastomer is used. is there.

For example, a woven fabric, a knitted fabric, a reticulated body, a non-woven fabric of elastomeric fibers composed of an elastomer yarn or an elastomer cord, or an elastomer-coated sheet thereof, an elastomer-containing sheet, or the like is appropriately selected and used. Further, a sheet of a composite fiber of the same elastic fiber and a non-elastic organic fiber made of regenerated fiber, natural fiber or synthetic fiber or metal fiber, a knitted fabric, a net, a sheet of non-woven fabric, or the above-mentioned non-elastic organic fiber, Alternatively, it is appropriately selected and used from an elastomer-coated sheet such as a non-woven fabric, a woven fabric, a knitted fabric or a net-like body of a composite fiber of the non-elastic organic fiber or metal fiber and an elastic fiber composed of an elastomer thread or an elastomer cord.

In the case of non-elastic organic fibers, since the elasticity is imparted by the elastomer coating, a texture having a coarse density is suitable, and for example, a two-ply cross-formed sheet of rubber-covered combed weave is used. The elastomer-coated sheet as the elastic support is obtained by thermoforming. Further, the number of plies and the thickness of the sheet are appropriately adjusted according to the application. Further, as a method of integrally forming the intermediate layer, a specific molding method that can obtain a desired shape at a desired position with high accuracy is used.

That is, in a forming die having a plurality of upper dies that are openably and closably connected around the lower die, the end of the elastic support is attached to and detached from the flange portion on the inner surface of the upper die for the upper layer designed to have the required shape. Fix it as close as possible and inject it, inject the foaming compounding liquid of soft low density foam into the lower mold, close the upper mold and perform heat foam molding, for the upper layer immediately before or after the end of the tack free time of the foam Open the upper mold and inject the foamable compounding liquid of soft high density foam onto the integrally molded elastic support,
The upper mold for the lower layer is closed and heat foaming is performed to continuously form a soft low density foam, an elastic support and a soft high density foam integrally.

Although the above-mentioned step is to insert the elastic support into the entire interface between the soft low-density foam and the soft high-density foam, the elastic support may be inserted only at a necessary partial position of the interface. . In this case, a desired number of needle-like protrusions (pins) are provided in advance at desired partial positions on the inner surface of the upper die for the upper layer, and elastic supports are inserted into the needle-like protrusions, which are detachably fixed and attached to the die. Alternatively, it is possible to take a means such as temporary fixed contact with an easily removable adhesive.

[Action]

In the seat cushion of the present invention, the elastic support having the elastic support property in the intermediate layer of the soft low-density foam and the soft high-density foam is heated in the same mold under the pressure of the upper mold for each layer. Since it is continuously formed into a desired shape at 1, a good fusion between molecules of each layer is obtained, and a strong integral structure of the foam with high precision as designed in position and shape is obtained.

Also, shock cushioning stress at the interface between the foam and the elastic support can be relaxed, and good cushioning properties and breakage at the interface can be suppressed. Furthermore, since an elastic support is interposed in the intermediate layer, there is no feeling of bottoming or discomfort, not only when it is thick, but also when the thickness of the seat cushion as a whole is as thin as 20-80 mm, there is no sense of harmony. Cushioning and sitting feeling are obtained.

〔Example〕

FIG. 1 is an end view of a central longitudinal section showing an example of a seat cushion of the present invention having an elastic support in an intermediate layer, and FIG. 2 is a half of a seat cushion molded product similar to that of FIG. FIG. 3- (a) is a sectional view taken along the line IIIa-IIIa of the molded article shown in FIG. 3, and FIG. 3- (b) is a sectional view taken along the line IIIb-IIIb shown in FIG. Similarly, FIG. 3C is a sectional view taken along line IIIc-IIIc.

In the figure, 1 is a flexible low-density foam, and in this example, a flexible polyurethane foam having a density of 0.045 to 0.055 was used as an example. 2 is a flexible high density foam, and in this example, a flexible polyurethane foam having a density of 0.05 to 0.065 was used as an example. Here, the low density and the high density are used to set the density difference between the upper and lower foams, and various combinations of the difference densities are formed according to the application and the use conditions. Reference numeral 3 is an elastic support integrally formed with the intermediate layer of the laminate composed of low-density and high-density foam. In this example, polyurethane-based elastic fiber was used. The physical properties of this type of elastic fiber are generally the tensile strength.
0.5-1.0 g / d, elongation 450-800%, specific gravity 1.0-1.3. SF is a seating surface, SS is a side surface on both sides of the seating surface, and is formed in a raised shape. The soft low-density foam 1, the soft high-density foam 2 and the elastic support 3 are also formed as shown in the sectional view of FIG. , Are formed in a ridge shape along both sides of the seat surface.

The above-mentioned shape is an example, and various shapes are appropriately used depending on the application and the use conditions.

Next, a method for integral foam molding of the seat cushion will be described.

FIG. 4 is a schematic cross-sectional view showing a central cross section of a molding die used in this seat cushion molding method, which is a molding die corresponding to the seat cushion molded product shown in the perspective view of FIG. In the figure, 4 is a lower mold, 5 is an upper mold upper mold for integrally molding the soft low-density foam 1 and the elastic support 3, and 5F is a flange portion of the upper mold mold. 6
Is an upper mold for the lower layer that molds soft high-density foam,
Hinge joints 7 and 8 are joints for rapidly fitting and releasing the upper molds 5 and 6 on the lower mold 4 alternately. The upper mold is opened and closed automatically by a hydraulic mechanism. Although various methods can be used for heating, this example uses an aluminum mold,
Adopted a pipe system in which a heat medium pipe is cast during casting.
In the temperature range of 50 ° C. to 100 ° C., an appropriate temperature is selected according to the compounding composition of the materials used, and the mold temperature is uniformly and accurately adjusted by the heat medium.

Next, the molding procedure will be described.

First, the mold is adjusted so as to be maintained at 65 ° C. As shown in FIG. 4, the elastic support body 3 is attached to the flange portion 5F at the end edge portion thereof so as to be attachable to and detachable from the flange portion 5F, and the main body portion is attached to the inner surface of the upper die 5 for the upper layer. The mold 4 is filled with a foamable compounding liquid that forms a soft low density foam,
As shown in the figure, the upper layer upper mold 5 is closed, and heat foaming is performed. Immediately before or after the end of the tack free time of the foamed body, the upper layer upper mold 5 is opened as shown in FIG.
A flexible high-density foaming compounding liquid is injected from the injection head 10 onto the integrally molded elastic support 3, and as shown in FIG. 7, the lower layer upper mold 6 is closed and heat foaming is performed. After the completion of foaming, curing is performed for about 2 minutes and the upper mold 6 for the lower layer is opened and the molded product is taken out from the lower mold 4. As shown in FIGS. 2 and 3, the soft low-density foam and the soft high-density foam are separated. A seat cushion product in which an elastic support is integrally formed as an intermediate layer at the interface can be obtained.

〔The invention's effect〕

The seat cushion according to the present invention comprises an intermediate layer of an elastic support member having a required shape integrally foam-molded on one surface of a soft low-density foam, and a flexible high-density foam, which are integrally laminated in a required shape with the same mold. Therefore, it is possible to exhibit the excellent function as mentioned in the above-mentioned action section, and in particular, with a seat cushion which is thin and suitable for a limited space in an automobile, and which has a good seating feeling. Not only that, but also provides excellent cushioning effect in other applications.

Also, because of the strong integral structure of the foam and the elastic support,
The local destruction at the interface due to the large difference in physical properties between the foam and the rigid body as in the past is suppressed, and excellent durability effect is obtained.

Further, the molding method of the present invention allows the elastic support to be accurately arranged even when there is a curved portion or a concave-convex portion at the interface between the upper layer portion and the lower layer portion, and therefore the degree of freedom in designing the structure of the seat cushion is increased. The large size provides a structurally optimal seat cushion.

[Brief description of drawings]

FIG. 1 is an end view of a central longitudinal section showing an example of the seat cushion of the present invention, FIG. 2 is a central longitudinal perspective view of the same, and FIG. 3- (a) is a sectional view taken along line IIIa-IIIa of FIG. 3 (b) is a sectional view taken along line IIIb-IIIb, and FIG. 3 (c) is a sectional view taken along line IIIc-IIIc, FIG. 4 and FIG.
FIG. 6, FIG. 7 and FIG. 7 are schematic cross-sectional views showing a cross section of a molding die used in an example of the seat cushion of the present invention and a molding procedure. 1 ... Soft low-density foam 2 ... Soft high-density foam 3 ... Elastic support 4 ... Lower mold 5 ... Upper mold upper mold 5F ... Upper mold upper flange 6 ... Lower mold upper mold 9 , 10 …… Injection head

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Claims (6)

[Claims] 1. An intermediate layer of an elastic support having a required shape integrally foam-molded on one side of a soft low-density foam by a mold,
A seat cushion characterized by being integrally laminated with a desired shape by using a soft high-density foam in the same mold. 2. The seat cushion according to claim 1, wherein the seat cushion is formed into a thin sheet having a total thickness of 20 to 80 mm with an elastic support interposed. 3. An elastic support is a support selected from a woven fabric, a knitted fabric, a net-like body, a non-woven fabric of elastomeric fibers composed of an elastomer yarn or an elastomer cord, or an elastomer-coated sheet thereof, a perforated elastomer sheet or the like. A seat cushion according to claim 1. 4. A woven fabric, a knitted fabric, or a reticulated body of a composite fiber in which an elastic support is composed of an elastic fiber made of an elastomer thread or an elastomer cord and an inelastic organic fiber made of a recycled fiber, a natural fiber or a synthetic fiber, or a metal fiber. The seat cushion according to claim 1, which is a support member selected from a non-woven fabric, a non-woven fabric, and the like. 5. The elastic support comprises a non-elastic organic fiber made of recycled fiber, natural fiber or synthetic fiber, or a composite fiber of the non-elastic organic fiber or metal fiber and elastic fiber made of elastomer yarn or elastomer cord. Non-woven, woven,
The seat cushion according to claim 1, which is a support selected from elastomer-coated sheets such as knits and nets. 6. A mold having a plurality of upper molds openably and closably connected to the periphery of the lower mold, wherein an elastic support is detachably attached to the inner surface of the upper mold for the upper layer, and the lower mold is for soft low-density foam. Injecting the foamable compounding liquid, closing the upper mold for the upper layer, and performing heat foam molding, open the upper mold for the upper layer immediately before or after the end of the tack free time of the foam, and soften it on the elastic support integrally molded. It is characterized in that a low-density foam, an elastic support, and a soft high-density foam are continuously and integrally molded by injecting a foaming compounding liquid for high-density foam, closing the upper mold for the lower layer and performing heat-foam molding. Seat cushion molding method.