JP3056605B2 - Soft polyurethane seat cushion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible polyurethane seat cushion suitably used in the fields of automobile seats and furniture chairs.

[0002]

2. Description of the Related Art In a seat or furniture chair of an automobile, a flexible polyurethane molded foam is directly mounted on a steel spring, and a covering material is coated on the flexible polyurethane molded foam to produce a desired seat or chair. . In this case, the portion of the flexible polyurethane mold foam which comes into contact with the steel spring was easily worn and damaged by friction. In order to remedy the above-mentioned drawback, a nonwoven fabric for reinforcement or a coarse blanket has been integrally laminated on a portion of the flexible polyurethane mold foam which comes into contact with the steel spring.

[0003]

As the above-mentioned nonwoven fabric which has been generally used, for example, there is a spunbond type nonwoven fabric produced by fixing polyester filaments by self-adhesion. It has almost no elasticity. On the other hand, a nonwoven fabric called a coarse blanket is obtained by subjecting short fibers to light resin processing, and lacks elasticity and elasticity. By the way, when this kind of nonwoven fabric or coarse blanket is integrally foamed when a soft polyurethane foam stock solution is poured into a mold to form a seat cushion, the nonwoven fabric or coarse blanket is impregnated with the foaming liquid, and the reinforcing layer expands and contracts. Sex is almost zero. Therefore, when such a flexible polyurethane molded foam is placed on a steel spring and covered with a skin material and used as a seat or a chair, the flexible polyurethane molded foam and the steel spring bend under the load of the human body, but the flexible polyurethane molded foam is bent. The part of the non-woven fabric or coarse blanket integrally molded with the foam does not sag and brings a feeling of strangeness or discomfort to the human body in a sitting comfort. Thus, an object of the present invention is to provide a seat cushion in which a soft polyurethane mold foam is placed on a steel spring, and a seat cushion caused by a conventional reinforcing nonwoven fabric integrated with the soft polyurethane mold foam is used. It is an object of the present invention to provide a seat cushion that eliminates discomfort and discomfort and improves sitting comfort.

[0004]

The present invention has been accomplished as a result of intensive studies to solve the above-mentioned problems. That is, the present invention provides a seat cushion in which a soft polyurethane mold foam is placed on a steel spring.
A flexible polyurethane foam having elasticity with a breaking elongation of 150% or more made of elastic fiber is provided at a portion of the flexible polyurethane mold foam which comes into contact with the steel spring.
Non- woven fabric impregnated with liquid is integrally molded , and is integrally molded
The stretch of the nonwoven fabric thus obtained is
A soft polyurethane seat cushion is characterized in that the foam follows the behavior of the rigid spring .

It is important that the elastic nonwoven fabric used in the present invention does not impair the flexibility of the flexible polyurethane molded foam when it is integrally molded with the flexible polyurethane molded foam. Therefore, in practicing the present invention, a non-woven fabric made of elastic fibers made of a polyurethane or rubber-based elastomer, for example, by a spunbond method or a melt blow method, and having a high flexibility of a flexible polyurethane mold foam. It is desirable to select and use a stretchable nonwoven fabric exhibiting elongation and a high recovery rate. Specifically, 150% of an elastic fiber
A stretchable nonwoven fabric having the above elongation at break is suitable.

Examples of the elastic nonwoven fabric having such properties include a thermoplastic polyurethane elastomer spunbond (manufactured by Kanebo Co., Ltd., trade name: Espinshione) and a melt blown nonwoven fabric (stock: styrene / hydrogenated polyisoprene block copolymer). Kuraray Co., Ltd., trade name: Septon MB) and the like can be mentioned as particularly preferable examples.

As a method of integrally molding the above-mentioned stretchable nonwoven fabric at a predetermined portion of a flexible polyurethane mold foam, a stretchable nonwoven fabric is detachably fixed to the inner surface of an upper mold of a foaming mold, and a foaming stock solution for a flexible polyurethane foam is formed in a lower mold. , The upper mold is closed and foam-hardened, and then, the mold is removed to obtain a product, which is a so-called integral foam molding method. In this case, the elastic non-woven fabric is soft polyurethane
Whether the injection surface of the foaming foam solution is difficult to impregnate
Elongation even when impregnated
It is sufficient if the system follows the behavior of the rigid spring.

The physical properties of the stretchable nonwoven fabric according to the present invention and the conventional nonwoven fabric are shown in Table 1.

[Table 1]

[0009]

The flexible polyurethane seat cushion according to the present invention is constructed by using a stretchable nonwoven fabric at the steel spring contact portion of the flexible polyurethane mold foam, so that the steel spring itself is not affected by the load applied when the human body is seated. It is possible to freely expand and contract as close to the deflection as possible, and the spring characteristics as a seat cushion are improved. Specifically, even if the density and hardness of the flexible polyurethane mold foam are the same as those of the related art, the amount of deflection of the seat cushion increases, and the stroke feeling can be improved. In addition, an increase in the rebound rate leads to an improvement in the resilience, and furthermore, a decrease in both the resonance frequency and the 6 Hz transmission rate reduces discomfort such as motor sickness and improves ride comfort. You.

[0010]

Next, the features of the present invention will be described in more detail with reference to examples and comparative examples. Example A stretchable non-woven fabric having characteristics as shown in Table 2 (trade name: Espin Sione, manufactured by Kanebo Co., Ltd.) is cut into a predetermined size, and is cut through a fixing pin provided on the inner surface of the foam mold. After being detachably fixed, a foaming stock solution for a flexible polyurethane foam was poured into a lower mold, the upper mold was closed, foamed and cured, and the polyurethane foam and the nonwoven fabric were integrally molded to obtain a polyurethane pad for a seat cushion.

[0011]

[Table 2]

Next, the polyurethane pad is placed on a cushion panel provided with an S-shaped steel spring and covered with a skin material to prepare an automobile seat. It was measured by the method. The results are shown in Table 3. Foam density: Measured according to JIS K6401. 25% hardness: a value measured according to JIS K6401. The smaller the value, the softer and the more submerged. Deflection amount under a load of 50 kg: It is a deflection amount of a sheet measured according to JASO B407. Rebound rate: The initial rebound rate (%) measured when a butt-shaped load board is freely dropped according to the attenuation test of JASO B407, and the higher this value, the better the spring feeling (bounce condition). . Resonance frequency: a vibration frequency at a resonance point determined from a forced vibration characteristic diagram recorded by a vibration test of JASO B407, and a lower value is preferable. 6 Hz transmissivity: The transmissivity at 6 Hz determined from the same forced vibration test. The resonance frequency of the internal organs of a human is 6 to 8 Hz, and it is said that if the vibration transmitted from the automobile in this region is large, discomfort such as motion sickness is caused. Therefore,
The smaller this value is, the better.

In addition to the above, the following sensory tests were conducted to evaluate the riding comfort. Stroke sensation: A feeling of sinking deeply and not bottoming out when sitting down with the hips dropped. Rebound: This is a feeling of bouncing moderately when you touch your hips or hands. Fatigue: Numbness is felt in the buttocks and thighs after driving. Discomfort such as car sickness: In this case, it refers to the discomfort of a person sitting in the passenger seat. These test results are the average values of bodily stimuli that were scored in the following five stages after each of 20 panelists operated for 2 hours. Rating: 1 2 3 4 5 Stimulus: Weak <Strong

[0014]

[Table 3]

Comparative Example A polyurethane pad for a seat cushion and an automobile seat were prepared in the same manner as in the example except that a coarse blanket having the properties shown in Table 2 was used instead of the stretchable nonwoven fabric. Various characteristics relating to the riding comfort of the seat were measured by the above-described methods. The results are shown in Table 3.

[0016]

According to the present invention, a soft polyurethane seat cushion is formed by using a stretchable nonwoven fabric made of elastic fiber, so that unlike a conventional product using a nonstretchable nonwoven fabric, a feeling of incongruity in sitting comfort is improved. There was no discomfort, and good results were obtained in stroke feeling and repulsion feeling.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-137381 (JP, A) JP-A-1-227710 (JP, A) JP-A-61-932288 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) A47C ^7/ 18-7/30

Claims (1)

(57) [Claims] An elastic fiber having a basis weight of 50 to 300 g / m ² at a portion of the soft polyurethane mold foam which comes into contact with the steel spring in a seat cushion in which a soft polyurethane mold foam is placed on a steel spring. Having elasticity with a breaking elongation of 150% or more,
And a non-woven fabric impregnated with a flexible polyurethane foam stock solution is integrally molded, and the integrally molded non-woven fabric is
Elongation after impregnation with flexible polyurethane foam stock solution
A soft polyurethane seat cushion , wherein the flexible polyurethane mold foam follows the behavior of the steel spring.