JPH07106167B2 - Cushion - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushion body suitable for use as a seat pad for a vehicle seat or other general furniture, office furniture or other chair, or sofa, and in particular, A cushion body intended to maintain a posture when sitting is provided with partially different physical properties to enhance the posture retaining effect.

2. Description of the Related Art Conventional cushion bodies often use polyurethane foam or foam rubber as a material, and they are often produced by foaming with a predetermined mold or by cutting out.

In this case, since the cushion body is homogeneous and has a single physical property, there is a drawback in that it cannot be applied when it is desired to change the hardness depending on the location in order to maintain the sitting posture.

In order to compensate for this drawback, there is a method in which a cushion body made of another material is held in advance at a desired position, and polyurethane foam is foamed so as to come into contact with the cushion body to form a composite cushion body. Polyurethane foam resin surface is formed on the surface, and since this surface does not have cushioning properties, it may cause discomfort with other cushion parts, and the adhesive strength at the joint surface with other materials tends to be insufficient. Since it is also poor in properties, it cannot be said to be a preferable cushion body.

Recently, particularly in vehicle seats, a structure for naturally maintaining the sitting posture is often adopted. For example, as shown in the perspective view of FIG. 1, the back portion 1 of the backrest A and the seat portion 2 of the seat B can easily fit into the body. It has a shape, and ridges 3 for holding the upper body are provided on both sides of the back 1, and ridges 4 for holding the waist are also provided on both sides of the seat 2.

The raised portion 3 of the backrest A and the raised portion 4 of the seat portion B are important parts in terms of holding the driver's body. It goes without saying that, for example, if the body cannot be held by cornering while driving and the body moves sideways, the position of the eyes will shift and there will be a danger in driving. Therefore, the ridges 3 and 4 are usually made of a harder material than the back 1 and the seat 2 for holding the body, but the hardness of the back 1 and the ridge 3, the hardness of the seat 2 and the ridge 4 and the cushion If there is a big difference in feeling, it will give a discomfort when seated, and the seat will be uncomfortable to ride. So the back 1 and the ridge 3,
The seat portion 2 and the raised portion 4 are required to have a structure that is functionally different from each other in terms of feeling.

The structure of the A'-A "cross section of the backrest A shown in FIG. 1 when the above-mentioned conventional composite cushion body is used as a padding will be described with reference to FIG. 3, and the backrest having the raised portion 3 for a body holding function. The side member 5 is a relatively hard foam,
The back portion 1 is formed of a relatively soft foam body 11, but since the backrest side member 5 is a relatively hard foam body and has a low elongation strength, cracks form from the pull groove portion 7 due to repeated seating deformation. Easy to destroy.

Further, since the boundary surface 5'between the back portion 1 and the backrest side member 5 is a contact point of different materials having different hardness, the adhesive force is likely to be insufficient,
The present situation is that the peeling phenomenon is occurring.

The B'-B "cross section of the seat B also has the same structure as in FIG. 3, and the same problem occurs between the seat side member provided with the raised portion 4 and the seat portion 2.

In particular, the back portion 1 of the backrest A and the raised portion 3 are required to have a mutual cushioning property. The back part 1 should have a comfortable cushioning feeling when leaning on the upper body, but the raised part 3 has a mission of a holding tool to prevent the body from swaying left and right, and has a cushioning property according to each purpose. is necessary. However, the composite cushion body having the structure shown in FIG.
And the raised portion 3 are not preferable because a large difference is generated in the feeling.

JP-A-55-96195 discloses a hard polyurethane foam layer and a flexible polyurethane foam layer, which are bonded together along an interface without using an adhesive. Although a multilayer specific gravity foam product is disclosed, this cushion body is merely a stack of different cushion bodies and has a special effect in terms of a driver's body retention function. Not a thing.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention provides a cushion for a seat padding that is comfortable in sitting and has an excellent effect in terms of a body-holding function as well as strength and productivity. Intended to provide the body.

Means for Solving the Problems The cushion body of the present invention comprises a first polyurethane foam and a first polyurethane foam at an arbitrary position in the raw material of the first polyurethane foam which is injected into the foam molding mold and is being foamed. Is characterized in that it has a structure in which the raw material of the second polyurethane foam having different physical properties is injected, and the raw material of the first polyurethane foam is wrapped and foamed and integrated.

In this case, the first polyurethane foam is usually a relatively soft polyurethane foam and the second polyurethane foam is a relatively hard polyurethane foam.

The present invention will be described with reference to FIG. 2 by taking the structure of the A′-A ″ cross section of the backrest A of the vehicle seat illustrated in FIG. 1 as an example. The backrest 1 and the backrest having a raised portion 3 for a body-holding function. A relatively hard second polyurethane foam 12 is placed in the ridge 3 in the relatively soft first polyurethane foam 11 with integrated side surfaces.
The polyurethane foam 11 is wrapped and foam-molded into a united body.

Therefore, the second polyurethane foam 12 is embedded in the first polyurethane foam 11, and the second polyurethane foam 12 does not appear on the surface. However,
Even if the second polyurethane foam 12 appears on the first polyurethane foam 11 to some extent, it does not matter in the place where the second polyurethane foam 12 is functionally less affected and is within the scope of the present invention.

B'- in the seat B of the vehicle seat illustrated in FIG.
The structure of the B ″ cross section is also similar to the structure of the cross section of the backrest A shown in FIG.

The cushion body having the cross-sectional structure illustrated in FIG. 2 is a relatively hard portion that gives a feeling of strangeness when seated in the conventional cushion body.
12 (corresponding to 5 in FIG. 3) is wrapped in a relatively soft polyurethane foam 11 suitable for seating, and since both are foam-molded at the same time, the contact surface has no discomfort. When seated, there is no great difference in initial feeling between the two, and the back part 1 functionally has a very comfortable cushioning property, and the raised part 3 has an extremely excellent effect of stabilizing the body.

Further, in the conventional cushion body shown in FIG. 3, there is a problem that the contact point 5 ′ between the foreign material 5 and the foam body 11 is insufficiently adhered and peeled off. However, in the present invention illustrated in FIG. The contact surface between the polyurethane foam 11 and the second polyurethane foam 12 is peeled off because the second polyurethane foam 12 is embedded in the first polyurethane foam 11 and is simultaneously foam-molded. Problem does not occur.

Further, a relatively hard material used for holding the body has a high cost, but in the present invention, it is possible to use a material having a high cost only in a necessary portion, that is, a material having a high hardness. Since the required volume is smaller than that of, the cost is lower than that of the conventional cushion body.

Here, as shown in FIG. 2, the relatively hard second polyurethane foam is wrapped with the first polyurethane foam at an arbitrary position in the relatively soft first polyurethane foam. The method for manufacturing a cushion body having an integrated structure that is foam-molded in a closed state
This will be described in detail with reference to FIGS.

In FIGS. 4 to 7, reference numeral 20 is a mold for foam molding.

First, as shown in FIG. 4, a relatively soft polyurethane foam raw material 21 is stirred at a high speed by a mixing head (not shown), and injected from the nozzle 10 into the mold interiors 23 and 24 corresponding to the ridges and back. To do.

Next, as shown in FIG. 5, the foam material 21 inside the mold
Is 20 to 60% of the total foaming amount (foaming amount when foaming is completed)
After foaming to some extent, a relatively hard polyurethane foam raw material 22 is agitated at high speed with a mixing head (not shown), and the inside of the mold corresponding to the ridge 3 from the nozzle 10 'is stirred.
At 23, a further injection is made into the already injected relatively soft polyurethane foam foam material 21.

The foam raw material 21 injected earlier has a low specific gravity due to foaming of about 20-60%, so the foam raw material injected later
22 dive into the foam raw material 21.

Alternatively, after the relatively soft foam raw material 21 is foamed by about 20 to 60% with respect to the complete foaming amount, the relatively hard foam raw material 22 is stirred at a high speed with a mixing head as shown in FIG. Is injected into the inclined surface 23 ′ of the mold inside 23. The injected raw material 22 travels along the slope and dives into the relatively soft foam raw material 21 that has already been injected.

In any case, as shown in FIG. 7, the relatively hard polyurethane foam foam raw material 22 added later is wrapped in the relatively soft polyurethane foam foam raw material 21 added previously. Then, both raw materials are foamed after a cream time and a rise time suitable for their prescription and atmosphere, and are filled in the mold 20 to form a cushion body having the structure shown in FIG.

Next, the composition of the polyurethane foam foam raw material is shown in Table 1, and the production method such as the timing of injecting the relatively soft polyurethane foam foam raw material after the injection of the relatively soft polyurethane foam foam raw material will be described in detail. However, the present invention is not limited to this specific example.

Raw materials of different formulations as exemplified in Table 1 were injected into the same place, and as shown in FIG. 7, the relatively hard polyurethane foam raw material 22 was replaced with the relatively soft polyurethane foam foam raw material 21. In order to be wrapped in the inside of the, after the raw material injected earlier (raw material of the relatively soft polyurethane foam) foamed about 20-60% of the complete foaming amount (in the formulation shown in Table 1 6 after starting the previous raw material injection
30% foaming in 30 seconds) is injected with the raw material after the pre-cream state (relatively hard polyurethane foam raw material), but the timing of injecting this raw material and the momentum (speed etc.) when the injection liquid sunk It is essential.

If the injection timing of the raw material to be added later is early, or if the injection liquid has a strong diving force, as disclosed in Japanese Patent Laid-Open No. 55-96195, the raw material that is added later has a raw material layer that is previously added. After passing, it becomes the lower layer, and the two raw materials become the upper and lower two layers, and the raw material put in later is not wrapped in the raw material put in earlier.

Also, if the injection timing of the raw material to be added later is late,
Alternatively, when the momentum of injection is slow and the raw material to be added later is past the cream state and is in the rise state, the raw material added afterwards does not penetrate into the raw material added earlier and remains in the upper layer, and the two raw materials still remain. There will be two layers above and below.

That is, the raw material to be added later breaks the surface tension of the raw material after the start of the rise, enters the predetermined position without passing through the raw material of the previous rise, and is wrapped in the raw material of the previous addition. The timing of infusion is important.

The raw material to be added first may be a normal one having a cream time of about 6 seconds and a rise time of about 80 seconds to 100 seconds. On the other hand, the raw material to be added later is in a low viscosity state where it easily penetrates the raw material put earlier, has a long cream time of about 8 to 10 seconds, and has already entered the raw material and is wrapped in the raw material. It is preferable to use a composition that has a quick rise time of about 60 to 70 seconds so that it may be cured before it passes through the raw material layer put in.

EFFECTS OF THE INVENTION The cushion body according to the present invention is an integrated cushion body having partially different physical properties depending on the required cushion function, and there is no discomfort even at different interfaces,
It is also highly productive and has great utility value.

When the cushion body according to the present invention is used as a padding for a vehicle seat as shown in FIG. 1, the relatively hard polyurethane foam of the side ridges necessary for holding the body when sitting is rich in cushioning property. Since it is wrapped in a relatively soft polyurethane foam, the present invention has no discomfort when sitting, and has an excellent effect in terms of a body-holding function, as well as strength and productivity. Are better.

Compared to conventional products, it has two polyurethane foams with different hardness and cushioning properties integrated, but it does not feel discomfort when seated, resulting in a comfortable cushioning body.

The boundary surface between two different polyurethane foams does not have a strange feeling, and there is no fear of peeling or tearing due to insufficient adhesion between them.

There is no worry of deformation because the relatively hard polyurethane foam, which has low elongation and strength and is easily deformed by the load when seated, is wrapped with a relatively soft cushion.

A relatively hard raw material that is costly to hold the body is cheaper than prior art products because only the necessary parts need to be used.

And so on.

[Brief description of drawings]

FIG. 1 is a perspective view of a vehicle seat to which the cushion body of the present invention is applied, and FIG. 2 is a sectional view taken along line A′-A ″ or B′- of FIG.
The figure which shows the structure of the cushion body of this invention in B "cross section, FIG. 3 is the figure which showed the structure of the conventional composite cushion body for seats by the A'-A" cross section or B'-B "cross section of FIG. ,
4 to 7 are views for explaining a process of manufacturing the cushion body having the structure shown in FIG.

Claims (2)

[Claims] 1. A second polyurethane foam having a physical property different from that of the first polyurethane foam, at an arbitrary position in a raw material of the first polyurethane foam which is injected into the foam molding mold and is being foamed. A cushion body having a structure in which a body raw material is injected, and is wrapped and integrated with a first polyurethane foam raw material in a state of being foam-molded. 2. The cushion body according to claim 1, wherein the first polyurethane foam is a relatively soft polyurethane foam and the second polyurethane foam is a relatively hard polyurethane foam.