JP5684467B2 - cushion - Google Patents

Description

  The present invention relates to a cushion that is excellent in air permeability and has few defects in a molded product by molding a relatively high-density polyurethane foam and a relatively low-density polyurethane foam as materials.

For example, cushions for seats and backrests in the vehicle seat and other cushions for armrests are polyurethane foams obtained by molding a raw material containing polyols, polyisocyanates, a foaming agent and a catalyst with a mold. These cushions are composed of a high-density skin layer formed in contact with the inner surface of the mold at the time of molding, and an internal low-density core layer surrounded by the skin layer. And since the ratio which occupies for the whole core layer is large, the softness | flexibility and air permeability which are requested | required of a cushion are largely dependent on the physical property which this core layer exhibits. Note that the cushion is not limited to a vehicle seat but includes a wide range of seats used at home and at work.
The polyurethane foam as the cushion is a hot-cure mold product that has a relatively low density and does not require crushing (complete treatment) after demolding from the mold, and a relatively high density that is from the mold. There is a cold cure mold product that requires the crushing after demolding. The density of the hot cure mold product is about 0.021 to 0.029 g / cm ³ in overall. The cold cure mold product has a density of about 0.028 to 0.065 g / cm ³ .

JP, 8-258059, A The seat object which laminated the soft urethane foam sheet on the back side of the skin material is indicated.

  The cushion described above has physical properties such as a comfortable hardness and an appropriate air permeability that are universally required for various seats. The cushion is a polyurethane foam obtained by molding a polyurethane raw material using a mold as described above.

By the way, the molded product of polyurethane foam is not based on the above-mentioned molding, but there is a product generally called a soft slab foam. This is a long slab-shaped molded product which is obtained by continuously discharging and curing a reaction mixture composed of two liquids of a polyol and an isocyanate and a catalyst and other additives on a conveying surface of a belt conveyor under normal atmospheric pressure. Polyurethane foam. This soft slab foam has a density of about 0.02 to 0.035 g / cm ³ and is widely used in consumer and industrial fields such as packing cushioning materials, shock absorbing materials, water absorbing materials, and soundproofing materials. Widely used in.

  Since this soft slab foam is continuously formed into a long slab at the manufacturing site, it is cut into an appropriate length and then processed into various final products. For this reason, the factory produces a large amount of offcuts after processing the soft slab foam. And most of these scraps are currently disposed of as industrial waste. However, since the mill ends are cut out from a soft slab foam, there is no change in physical properties, and the way of effective utilization is being sought.

  Therefore, the applicant conceived of using such a large amount of soft slab foam end material to regenerate into a cushion for a seat, and polyurethane foam having physical properties such as hardness and breathability required for the cushion. Various experiments were conducted to obtain a body. For example, the end material of a soft slab foam is crushed into a pulverized product (chip) of the required crushed diameter, and this is molded to produce a seat cushion. Specifications such as hardness and breathability required for the cushion Confirmed that

FIG. 1 schematically shows a mold 10 used in this experiment, and the mold 10 includes an upper mold 12 and a lower mold 14 that define a cavity having a shape that defines the outer shape of the cushion. . The cavity of the lower mold 14 is filled with a mixture of the pulverized product (chip) of the soft slab foam and the required binder, the upper mold 12 is closed, and steam is passed through and cured by heating, followed by demolding. The physical properties of the obtained cushion were measured. However, this cushion has not cleared the expected value of breathability generally required for the cushion. The air permeability test was carried out by a measurement method defined by JIS K6400-7 (K2004-7: Method B of 2004) conforming to ASTM (American Society for Testing Materials). In this case, the breathability threshold required for the cushion was 10.0 ml / cm ² / sec.

  The following reasons can be considered as the reason why the air permeability of the cushion molded with the above specifications did not clear the expected value. That is, since the pulverized product of the soft slab foam has a low density, the filling amount of the pulverized product into the mold 10 must be made dense in order to achieve the hardness required for the cushion. However, since the pulverized product 16 having a large amount of filling becomes bulky as shown in FIG. 1, the cushion obtained by molding is greatly compressed, and as a result, the air bubbles become dense and air-permeable. That is why.

  For comparison, when a cushion was produced by molding the pulverized polyurethane foam molded as described above to the required crushed diameter using the mold 10, a breathability was required for the cushion. Met the expected value. This is because the density of the pulverized product of the polyurethane foam is relatively high, and even when the mold 10 is filled, the mold filling amount is not large (small in volume) as shown in FIG. Since it is not compressed enough, a large bubble diameter is secured, and as a result, the air permeability is considered to have cleared the expected value as a cushion. However, it is pointed out that the pulverized product is so small that it is not compressed so much that a defect (void) is likely to occur in the molded product after demolding.

  The present invention satisfies the expected value of the air permeability required for the cushion when the end material generated from the soft slab foam (polyurethane foam) is molded and reused in the cushion, and the molded product has a defect. The aim is to provide a cushion that does not occur.

In order to solve the above-mentioned object, the cushion according to the present invention has a hardness of 150 to 400 N measured by JIS K6400-2 D method , a density of 0.046 to 0.065 g / cm ³ measured by JIS K7222, and JIS K6400-7. A first pulverized product obtained by pulverizing a polyurethane foam having a measured air permeability of 40 to 60 ml / cm ² / sec to an average crushed diameter of ² to 10 mm , a hardness of 50 to 150 N, and a density of 0.020 to 0.025 g / cm ³ polyurethane A second pulverized product obtained by pulverizing a foam to an average pulverized diameter of 2 to 30 mm and a binder obtained by diluting a polyurethane-based binder using an amine-based curing agent with a halogenated solvent in a weight ratio excluding the binder. 1 pulverized product 80-90% by weight, and heating and compressing the mixture obtained by mixing the second grind at 20 to 10 wt% in the mold That.

  According to the present invention, it is possible to obtain a cushion that satisfies the air permeability required for the cushion and is less likely to cause a void (void) in the molded product after demolding.

It is the schematic of the open metal mold | die used for the experiment of this invention, Comprising: The state which fills the pulverized material with a small density and is bulked, and mold-molds is shown. The mold shown in FIG. 1 shows a state in which a pulverized product having a large density and a small bulk is filled and molded.

  The cushion according to the present invention includes a first pulverized product obtained by pulverizing a polyurethane foam produced by molding a polyurethane raw material to a predetermined crushed diameter, and pulverizing the aforementioned soft slab foam to a predetermined crushed diameter. The second pulverized product thus obtained is stirred and mixed together with a binder at a ratio of the required weight%, and the resulting mixture is heated and compressed in a mold to be cured and molded, so that the hardness required for the seat cushion and Both of the air permeability are satisfied.

  That is, the first pulverized product is obtained by pulverizing the polyurethane foam, which is the molded product, to the required crushed diameter. As this molded product, for example, a cushion obtained by peeling the skin from the seat portion or the backrest portion of the vehicle seat is preferably used. Moreover, the cushion used for the vehicle armrest may be sufficient. These cushions are molded products of polyurethane foam obtained by setting the skin of the seat for seats in a mold, filling with polyurethane raw material, and heating and foaming in the mold, and the cushion itself is a cushion. It has the required hardness and breathability.

For example, the polyurethane foam cushion, which is the molded product, has a hardness of 150 to 400 N and a density of 0.028 to 0.065 g / cm ³ . The air permeability is 40 to 60 (measured in accordance with JIS K6400-7 based on the ASTM). And the cushion of the said molded product is thrown into a grinder and grind | pulverized until it becomes an average crushed diameter of 2-10 mm, and a 1st ground material is obtained.

Further, the second pulverized product is obtained by pulverizing the above-mentioned end material of the soft slab foam to a required crushed diameter. The hardness of the polyurethane foam as the soft slab foam is 50 to 150 N, and the density is 0.020 to 0.025 g / cm ³ . The soft slab foam is put into a pulverizer and pulverized until the average pulverized diameter becomes 2 to 30 mm, whereby a second pulverized product is obtained.

  And, for example, 80 to 90 wt% of the first pulverized product, 20 to 10 wt% of the second pulverized product, and a binder described later are mixed and stirred, and the obtained mixture is filled in the mold 10, A cushion molded into a required shape is manufactured by heat-compressing and foam-curing this.

  As the binder, those that are cured by air moisture at atmospheric temperature are preferably used. Specifically, it is a polyurethane-based binder such as solvent-type polyurethane or two-component solventless polyurethane, and is cured by using moisture or heat as a trigger to bind the first pulverized product and the second pulverized product. . As the two-component solventless polyurethane, those using an amine curing agent such as triethylamine or N, N-dimethylcyclohexylamine are preferable. These binders are mainly composed of a high molecular weight material containing an active isocyanate such as toluene diisocyanate (TDI), and since this is highly viscous, it is diluted with an organic solvent.

  The organic solvent is preferably a halogenated solvent such as methylene chloride from the viewpoint of volatility and nonflammability. Specifically, a mixture of methylenediphenyl diisocyanate (MDI) and polyethylene glycol (PEG), or an amine catalyst added to these, or polypropylene glycol for soft urethane foam having a molecular weight of 2500-3500 and toluene diisocyanate (TDI). A urethane-based binder obtained by polyaddition and dilution with an appropriate solvent is used.

  And the addition mixing ratio with respect to the 1st ground material and the 2nd ground material of the said binder is 5 to 20 weight% of the said ground material, Preferably it is 10 weight%.

Hereinafter, various embodiments in which the physical properties such as the density of the first pulverized product and the second pulverized product, the mixing ratio of the two pulverized products, the binder type, and the like are changed will be described in comparison with the comparative example. The air permeability of the molded cushion was measured according to JIS K6400-7 based on the above-mentioned ASTM. In addition, the air permeability threshold allowed for the cushion was 10.0 ml / cm ² / sec as measured according to JIS K6400-7.

[First Embodiment]
The first pulverized product was obtained by disassembling the seat portion and the backrest portion of the vehicle seat and pulverizing the cushion body from which the skin was peeled off. As for the physical properties of the cushion used in this vehicle, even though it has passed a considerable period of time, almost no deterioration over time is observed. Therefore, as long as it is a cushion taken out from a scrapped vehicle, it may be from a state close to a new vehicle or from a used vehicle state.

The cushion obtained by disassembling the vehicle seat of a scrap car is a polyurethane foam molded as described above. In this case, the polyurethane foam had a hardness of 180 N, an air permeability of 50 ml / cm ² / sec (measured according to JIS K6400-7), and a density of 0.046 g / cm ³ . The polyurethane foam was put into a dry rotary pulverizer and pulverized to obtain a first pulverized product having an average pulverized diameter of 2 to 5 mm.

The second pulverized product was obtained by pulverizing the end material of the polyurethane soft slab foam described above. However, the use of the end material is for effective use, and it is a matter of course that a soft slab foam virgin material may be used. As described above, the soft slab foam is, for example, a polyurethane foam in which a two-component reaction mixture is continuously discharged and cured in the form of a belt conveyor under normal atmospheric pressure. The soft slab foam had a hardness of 100 N and a density of 0.025 g / cm ³ . The polyurethane foam as the end material was put into a dry pulverizer and pulverized to obtain a second pulverized product having an average pulverized diameter of 2 to 30 mm.

Next, 80% by weight of the first pulverized product and 20% by weight of the second pulverized product were mixed, and 10% by weight of toluene diisocyanate was added thereto as a binder, and the whole was mixed and stirred. The resulting polyurethane foam mixture was filled into a mold defining a cavity defining the outer contour of the finished cushion, and the mold was clamped and heat compressed. Further, dry steam was injected from the outside through a communication hole provided in the mold, and the binder was cured by reaction. After the mold was cooled, the mold was removed to obtain a seat cushion. The mold clamping time was 5 minutes, the mold heating temperature was 120 ° C., and the applied pressure was 5 kg / cm ² .
The air permeability of the cushion obtained by demolding at 14.3ml ^/ cm 2 ^/ sec as measured with JIS K6400-7, to clear the threshold 10.0ml ^/ cm 2 ^/ sec of the air permeability required for cushion, good Air permeability was ensured. The density of the cushion was 0.120 g / cm ³ . There was no defect in the cushion after demolding.

[Second Embodiment]
The first pulverized product was obtained by disassembling a vehicle armrest and pulverizing the cushion body from which the skin was peeled off. The cushion obtained by disassembling the vehicle armrest is a polyurethane foam molded as described above. In this case, the polyurethane foam had a hardness of 180 N, an air permeability of 50 ml / cm ² / sec (measured according to JIS K6400-7), and a density of 0.046 g / cm ³ . The polyurethane foam was put into a dry rotary pulverizer and pulverized to obtain a first pulverized product having an average pulverized diameter of 2 to 10 mm.

The second pulverized product was obtained by pulverizing the end material of the polyurethane soft slab foam described above. The soft slab foam had a hardness of 100 N and a density of 0.025 g / cm ³ . The polyurethane foam was put into a dry pulverizer and pulverized to obtain a second pulverized product having an average pulverized diameter of 2 to 30 mm.

Next, 50% by weight of the first pulverized product and 50% by weight of the second pulverized product were mixed, and 15% by weight of toluene diisocyanate was added thereto as a binder, and the whole was mixed and stirred. The obtained polyurethane foam mixture was filled in a mold, clamped and heat-compressed. Further, dry steam was injected from the outside through a communication hole provided in the mold, and the binder was cured by reaction. After the mold was cooled, the mold was removed to obtain a seat cushion. The mold clamping time was 5 minutes, the mold heating temperature was 120 ° C., and the applied pressure was 5 kg / cm ² .
Air permeability of the cushion obtained by demolding in 18.0ml ^/ cm 2 ^/ sec, to clear the threshold 10.0ml ^/ cm 2 ^/ sec of the air permeability required for cushion, good air permeability was secured . The density of the cushion was 0.120 g / cm ³ . There was no defect in the cushion as a molded product.

Table 1 shows the results of the first and second embodiments and the third and fourth embodiments described later in comparison with Comparative Example 1 and Comparative Example 2. From 3rd Embodiment to Comparative Example 2, it implemented by shape | molding on the conditions similar to 1st Embodiment except having changed the addition part number of the ground material.

  In the present invention, a pulverized product of two types of polyurethane foams having different densities is mixed with a binder at a required weight% and molded to obtain a cushion having excellent air permeability. The polyurethane foam used as a raw material before pulverization includes, for example, a cushion polyurethane foam obtained by disassembling a vehicle seat of a scrap car, and a polyurethane foam generated in a large amount as an end material of a soft slab foam. Since it can be used, the waste material can be recycled and used effectively. However, the raw material is not limited to the cushion and soft slab foam end material obtained by dismantling the scrap car, and the physical properties such as density are the same as those of the scrap car cushion and soft slab foam end material, respectively. If it is, it can be used as a raw material as it is.

10 Mold 12 Upper mold 14 Lower mold 16 Crushed material (chip)

Claims (3)

Polyurethane having a hardness of 150 to 400 N measured by JIS K6400-2 D method , a density of 0.046 to 0.065 g / cm ³ measured by JIS K7222, and an air permeability of 40 to 60 ml / cm ² / sec measured by JIS K6400-7 A first pulverized product obtained by pulverizing a foam to an average crushed diameter of 2 to 10 mm ;
A second pulverized product having a hardness of 50 to 150 N and a density of 0.020 to 0.025 g / cm ³ polyurethane foam pulverized to an average crushed diameter of 2 to 30 mm ;
A binder obtained by diluting a polyurethane binder using an amine curing agent with a halogenated solvent ,
A cushion obtained by heat-compressing a mixture obtained by mixing 80 to 90% by weight of the first pulverized product and 20 to 10% by weight of the second pulverized product in a weight ratio excluding the binder .   The cushion according to claim 1, wherein the first pulverized product is a pulverized product of polyurethane foam recovered from a vehicle seat, and the second pulverized product is a pulverized product of polyurethane foam as a soft slab foam. The binder is toluene diisocyanate or methylene diphenyl diisocyanate (MDI) and a prepolymer thereof, and is blended in a proportion of 5 to 20% by weight with respect to the mixture of the first pulverized product and the second pulverized product. The cushion described .

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