WO2020009239A1 - Polyurethane foam for seat pads, automobile seat pad, and production method for polyurethane foam for seat pads - Google Patents

Abstract

Provided is a polyurethane foam for seat pads, having high hardness as required for reducing member weight and also having excellent vibration absorption and deformation resistance. This polyurethane foam for seat pads is characterized by including a synthetic fiber that is insoluble in water and has a length of 0.1–5 mm.

Description

Polyurethane foam for seat pad, automotive seat pad, and method for producing polyurethane foam for seat pad

The present invention relates to a polyurethane foam for a seat pad, a seat pad for an automobile, and a method for producing a polyurethane foam for a seat pad.

Since flexible polyurethane foam has excellent cushioning properties, it is often used for seat pads of automobiles and the like.

On the other hand, especially in automobile parts, needs for weight reduction and wall thickness are increasing in recent years in order to improve fuel efficiency and secure a space inside the vehicle. This is not an exception for the seat pad, and there is a demand for a further improvement in the weight reduction of the seat pad, and thus the polyurethane foam.

Here, in the technology for reducing the weight of members, high hardness is an important issue. In this regard, as a technique for increasing the hardness of the polyurethane foam, it is known to use a polymer polyol containing a styrene / acrylonitrile copolymer (Patent Document 1).

JP 2010-189449 A

However, since the polymer polyol has a foam breaking effect, when a polymer polyol containing a styrene / acrylonitrile copolymer is frequently used to increase the hardness of the polyurethane foam, there is a problem that vibration absorption may be deteriorated due to foam breaking. there were. Such vibration absorption is one of the indices of comfort such as riding comfort with respect to a seat pad using a polyurethane foam, particularly an automobile seat pad, and the polyurethane foam has a vibration absorption in a frequency region required for the seat pad. It is important to be excellent.

On the other hand, as a countermeasure against the above-described deterioration of the vibration absorption, a method of blending a foam stabilizer or increasing the amount of the foam stabilizer to be blended to enhance the closed cell properties can be considered. However, in this case, there is a possibility that the deformation preventing property may be deteriorated, for example, wrinkles may be formed after polyurethane foam molding.
Therefore, there is room for improvement in the conventional polyurethane foam in that high hardness, vibration absorption, and deformation prevention are made parallel.

An object of the present invention is to provide a polyurethane foam for a seat pad which has high hardness required for weight reduction of members, and is excellent in vibration absorption and deformation prevention. Another object of the present invention is to provide a method for producing a polyurethane foam for a seat pad, which is capable of producing the polyurethane foam for a seat pad while suppressing cell coarsening. Another object of the present invention is to provide an automobile seat pad which has high hardness and is excellent in vibration absorption and deformation prevention.

The present inventors have conducted intensive studies to achieve the above object, and as a result, surprisingly, by adjusting the synthetic fiber to a predetermined length and using it for polyurethane foam, high hardness is achieved and deformation is prevented. The present inventors have found that the properties are improved, and that the vibration absorption is also improved.

That is, the polyurethane foam for a seat pad of the present invention is characterized in that it contains a synthetic fiber which is insoluble in water and has a length of 0.1 to 5 mm.

自動 車 Further, an automobile seat pad according to the present invention includes the above-described polyurethane foam for a seat pad. Such an automobile seat pad has high hardness and excellent vibration absorption and deformation prevention.

Further, the method for producing a polyurethane foam for a seat pad of the present invention includes a step of obtaining the above-mentioned polyurethane foam for a seat pad by molding.

According to the present invention, it is possible to provide a polyurethane foam for a seat pad which has high hardness required for weight reduction of members, and is excellent in vibration absorption and deformation prevention. Further, according to the present invention, it is possible to provide a method for producing a polyurethane foam for a seat pad, which is capable of producing the polyurethane foam for a seat pad while suppressing cell coarsening. Further, according to the present invention, it is possible to provide an automobile seat pad which has high hardness and is excellent in vibration absorption and deformation prevention.

本 Hereinafter, the present invention will be described in detail based on its embodiments.

(Polyurethane foam for seat pad)
The polyurethane foam for a seat pad according to one embodiment of the present invention (hereinafter sometimes referred to as “polyurethane foam of the present embodiment”) contains synthetic fibers that are insoluble in water and have a length of 0.1 to 5 mm. This is one of the features. By using the synthetic fiber having the predetermined length in the polyurethane foam, the apparent reaction rate is improved, and the hardness immediately after the polyurethane foam is manufactured (for example, at the time of demolding after molding) can be improved. Manufacturing and processing defects such as wrinkles that occur later and marks on the polyurethane foam when removed (the polyurethane foam is deformed) can be reduced. Therefore, the polyurethane foam of the present embodiment has high anti-deformation property, particularly high anti-deformation property immediately after production. In addition, by using the above-described synthetic fiber having a predetermined length for the polyurethane foam, the air permeability is optimized, and the vibration absorption, particularly the vibration absorption for a vibration having a frequency of 10 Hz or less can be improved. In addition, although the above-mentioned improvement of the deformation prevention property and the vibration absorption property is not certain, it is considered that the synthetic fiber of a predetermined length has some influence on the foam breaking effect of the polyurethane foam. .
In this specification, “insoluble in water” means that the solubility in 100 g of water is 1 g or less at normal temperature (for example, 25 ° C.).

ポ リ ウ レ タ ン The polyurethane foam of the present embodiment is used for a seat pad of an automobile or the like. And for such a use, the polyurethane foam of the present embodiment is preferably a flexible polyurethane foam. Here, in the present specification, the term "soft polyurethane foam" refers to a polyurethane foam having open cells and having resilience to a load.

<Synthetic fiber>
The synthetic fiber used in the present embodiment needs to have a length of 0.1 to 5 mm. If the length of the synthetic fiber is less than 0.1 mm, the effect of improving the hardness immediately after the production of the polyurethane foam and, consequently, the effect of improving the anti-deformation property cannot be sufficiently obtained. On the other hand, if the length of the synthetic fiber exceeds 5 mm, it becomes difficult to uniformly disperse the synthetic fiber during the production of the polyurethane foam due to thickening, and the vibration absorption and wet heat durability are deteriorated. It is not suitable for the production of
In addition, the length of the synthetic fiber used in the present embodiment is preferably 0.5 mm or more, more preferably 1 mm or more, from the viewpoint of further improving deformation prevention. Further, the length of the synthetic fiber used in the present embodiment is preferably 4 mm or less, and more preferably 2 mm or less, from the viewpoint of improving uniform dispersibility, and further from the viewpoint of further improving vibration absorption and wet heat durability. Preferably, there is. However, the preferable length of the synthetic fiber cannot be unconditionally determined, and it is considered that there is an optimum length depending on the fiber type.

The synthetic fiber used in the present embodiment is not particularly limited as long as it is a fiber made of an organic compound obtained by synthesis, which is insoluble in water, and can be appropriately selected depending on the purpose. The material of the synthetic fiber may be a single type or a combination of two or more types. The synthetic fiber used in the present embodiment is preferably at least one selected from rayon fiber, nylon fiber, aramid fiber, polyethylene terephthalate (PET) fiber, and polyethylene naphthalate (PEN) fiber. Rayon fiber or nylon Fiber is more preferable, and rayon fiber is more preferable.
In this specification, the term “synthetic fiber” does not include a fiber composed of a structural protein (a protein having a role of constructing a biological structure) produced by insects and spiders.

合成 The fiber diameter of the synthetic fiber used in the present embodiment is preferably 1 to 50 μm. If the fiber diameter of the synthetic fiber is 1 μm or more, the workability becomes good. On the other hand, if the fiber diameter is too small, the viscosity increases when mixed with a polyol component or the like, and becomes difficult to mix when mixed with an isocyanate component, which may cause deterioration in moldability. However, if the fiber diameter is 1 μm or more, such a situation can be avoided more reliably. When the fiber diameter of the synthetic fiber is 50 μm or less, the dispersibility of the synthetic fiber in the flexible polyurethane foam increases, and the hardness can be further improved. From the same viewpoint, the fiber diameter of the synthetic fiber is more preferably 5 μm or more, still more preferably 7 μm or more, further preferably 9 μm or more, and particularly preferably 11 μm or more. Further, the fiber diameter of the synthetic fiber is more preferably 41 μm or less, further preferably 36 μm or less, still more preferably 31 μm or less, even more preferably 26 μm or less, and more preferably 20 μm or less. Still more preferably, it is particularly preferably 17 μm or less, and most preferably 15 μm or less.

合成 The content of the synthetic fibers in the polyurethane foam of the present embodiment is not particularly limited, and may be, for example, 0.5 to 5% by mass. However, from the viewpoint of the balance between the deformation preventing property and the vibration absorbing property, the content of the synthetic fiber in the polyurethane foam of the present embodiment is more preferably 1% by mass or more, and 2% by mass or less. More preferred.

The synthetic fibers used in the present embodiment are preferably coated with at least one oil agent selected from mineral oil, animal and vegetable oils and fats, and synthetic oil. Thereby, the synthetic fibers can be more uniformly dispersed in the polyurethane foam, and the hardness of the polyurethane foam can be further improved. The method for coating the oil agent is not particularly limited, and examples thereof include a dip nip method and a shower-like injection method. Further, from the viewpoint of further improving the uniform dispersibility, the oil agent more preferably contains a mineral oil.
The oil agent may alternatively be a water-insoluble oil agent such as a hydrocarbon, or a water-soluble oil agent such as an ionic and nonionic activator.

合成 The synthetic fiber used in the present embodiment can be manufactured by spinning according to a known spinning method such as a melt spinning method, a wet spinning method, or a dry spinning method. Further, the above-described coating of the oil agent may be performed in the process of manufacturing the synthetic fiber.

<Manufacture of polyurethane foam>
The polyurethane foam of the present embodiment is, for example, a polyol component, an isocyanate component, a catalyst, and a foaming agent, and, if necessary, the above-described synthetic fiber cut to a predetermined length using a fiber cutting machine or a crusher; From a foaming stock solution prepared using a foam stabilizer and / or a crosslinking agent.
In addition, the above-mentioned foaming undiluted solution is prepared by mixing a material other than the isocyanate component among the above-mentioned materials to obtain a mixture in which the synthetic fibers are sufficiently dispersed, and then mixing the obtained mixture with the isocyanate component. Is preferred.
In addition, from the viewpoint of minimizing the contact between the foaming agent and the catalyst, the mixture is blended with a catalyst in the polyol component, then optionally blended with a foam stabilizer and a crosslinking agent, and finally blended with a foaming agent. It is preferably prepared by

Examples of the polyol component include polyhydric alcohols having 2 to 6 valences, polyoxyalkylene polyols (polyether polyols), polyester polyols, and polymer polyols. Among them, as the polyol component, it is preferable to use at least one of a polyether polyol and a polyester polyol, and it is more preferable to use at least a polyether polyol. The polyol component may be used alone or in combination of two or more. As the polyol component, it is desirable to use a polyether polyol and a polymer polyol in combination. Here, the polymer polyol refers to a dispersion of fine particles made of a styrene and / or acrylonitrile copolymer in a polyether polyol. The polyether polyol component is obtained by ring-opening polymerization of ethylene oxide (hereinafter referred to as “EO”) and propylene oxide (hereinafter referred to as “PO”), and has a molar ratio of repeating units derived from EO and PO. Is preferably 10/90 to 25/75 (EO / PO), and a polyether polyol having a number average molecular weight of 4,000 to 12,000. Further, the number average molecular weight of the polyether polyol is more preferably from 4,700 to 8,000. This polyether polyol may be used alone or in combination of two or more.

From the viewpoint of durability, the average number of functional groups of the polyether polyol is preferably 3 to 5. The polyol component contained in the polymer polyol preferably has a number average molecular weight of 2,500 to 8,500. If the number average molecular weight of the polyol component contained in the polymer polyol is too low, it may adversely affect the stress relaxation of the polyurethane foam, and if the number average molecular weight is too high, the viscosity becomes high, and the stirring dispersibility and the workability are increased. There is a possibility that the property is adversely affected.
Since the polymer polyol contains the styrene and / or acrylonitrile copolymer as described above, it may contain a trace amount of a styrene monomer or the like, and may cause odor or contribute to harmful volatile substances in the vehicle interior space. .
The above number average molecular weight is a value calculated as a polystyrene equivalent value by gel permeation chromatography (GPC method).

Examples of the isocyanate component include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate, triphenyl diisocyanate, xylene diisocyanate, polymethylene polyphenylene polyisocyanate, methylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and ortho toluidine diisocyanate. , Naphthylene diisocyanate, xylylene diisocyanate, lysine diisocyanate, and derivatives thereof. The isocyanate component may be used alone or in combination of two or more. Particularly, as the isocyanate component, from the viewpoint of the density of the obtained polyurethane foam, it is preferable to use at least one of TDI and MDI, and it is more preferable to use TDI and MDI together.

As the catalyst, those commonly used in the production of polyurethane foams can be used. For example, TEDA [1,4-diazabicyclo [2.2.2] octane], N, N, N ′, N′-tetramethylhexa Methylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N ′, N ″ -pentamethyldiethylenetriamine, trimethylaminoethylpiperazine, N, N-dimethylcyclohexylamine, N, N N-dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, triethylamine, tributylamine, bis (dimethylaminoalkyl) piperazine, N, N, N ', N'-tetramethylethylenediamine, N, N-diethylbenzylamine , Bis (N, N-diethylaminoethyl) adipate, N, N, Tertiary amines such as', N'-tetramethyl-1,3-butanediamine, N, N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole, 2-methylimidazole, dibutyltin dilaurate, oleic acid Examples include organometallic compounds such as stannous, cobalt naphthenate, lead naphthenate, etc. The catalyst may be used alone or in combination of two or more.
The amount of the catalyst to be used is generally 0.1 to 5 parts by mass, more preferably 0.2 to 1 part by mass, per 100 parts by mass of the polyol component.

Water is preferably used as the foaming agent. Water acts as a blowing agent because it reacts with the isocyanate component to generate carbon dioxide gas. In addition to the water, a foaming agent usually used in the production of a polyurethane foam, for example, a hydrogen atom-containing halogenated hydrocarbon, liquefied carbon dioxide, or a low-boiling hydrocarbon can also be used.
The amount of the foaming agent to be used is preferably 0.1 to 10 parts by mass, more preferably 2 to 7 parts by mass, based on 100 parts by mass of the polyol component. When the amount of the foaming agent is 0.1 parts by mass or more based on 100 parts by mass of the polyol component, a sufficient effect of suppressing the wobble property can be obtained.

As the foam stabilizer, those commonly used in the production of polyurethane foam can be used. For example, silicone-based foam stabilizers such as various siloxane-polyether block copolymers can be used. Commercially available foam stabilizers include, for example, “SZ1325” manufactured by Dow Corning Toray, “B8742LF2” manufactured by EVONIK, and the like.
The amount of the foam stabilizer to be used is generally 0.5 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the polyol component. When the amount of the foam stabilizer is 0.5 parts by mass or more based on 100 parts by mass of the polyol component, the stirring property of the polyol component and the isocyanate component does not decrease, and a desired polyurethane foam is obtained, and 5 parts by mass or less. Is preferable in terms of cost. Further, from the viewpoint of further improving the deformation preventing property of the obtained polyurethane foam, the amount of the foam stabilizer used is preferably 1 part by mass or less based on 100 parts by mass of the polyol component.

As the cross-linking agent, those commonly used in the production of polyurethane foams can be used. For example, low-molecular-weight polyhydric alcohols (for example, those having a number average molecular weight of 1,000 or less obtained by single ring-opening polymerization of EO or PO) can be used. Polyether polyols, ethylene glycol, 1,3-propanediol, 1,4-butanediol, glycerin, etc.), low molecular weight amine polyols (eg, diethanolamine, triethanolamine, etc.) or polyamines, eg, ethylenediamine, xylylenediamine, methylene Bis-orthochloroaniline). The crosslinking agents may be used alone or in combination of two or more.
The amount of the crosslinking agent used is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polyol component. When the amount of the cross-linking agent is 0.5 parts by mass or more based on 100 parts by mass of the polyol component, the effect of the cross-linking agent is sufficiently obtained. In addition, moldability can be ensured, and occurrence of foam down can be suppressed. When two or more crosslinking agents are used, the total amount of the crosslinking agents is preferably 1 to 12 parts by mass.

The polyurethane foam of the present embodiment can be obtained by molding. More specifically, the polyurethane foam of the present embodiment is not particularly limited, and the above-mentioned foaming stock solution is injected into a cavity in a mold, and the mold is molded at a temperature of 50 to 70 ° C. and a curing time of 5 to 7 minutes according to a conventional method. It can be obtained by molding (foam molding). At that time, timed pressure release (TPR) may be used together. TPR is an operation for lowering the pressure in a mold to make bubbles communicate. More specifically, after injecting the foaming undiluted solution into the cavity in the mold, after 20 to 50 seconds have elapsed from the gel time (the time when the polyol component and the isocyanate component are mixed and the viscosity increases and the gel strength starts to appear) This is an operation for reducing the pressure in the mold by 0.15 to 0.25 MPa.

ク ラ The molded polyurethane foam can be subjected to a crushing treatment using a roller or the like. The crushing process is a process of breaking the cell membrane of bubbles generated during foam molding and stabilizing the foams for the purpose of stabilizing the shape of the foam and suppressing shrinkage.

(Production method of polyurethane foam for seat pad)
A method for producing a polyurethane foam for a seat pad according to one embodiment of the present invention (hereinafter, sometimes referred to as a “production method of the present embodiment”) includes a step of obtaining the above-described polyurethane foam by molding. And In the manufacturing method of the present embodiment, by performing molding, the above-described polyurethane foam can be manufactured while suppressing cell coarsening. The molding is as described above. In addition, in the production method of the present embodiment, there is no particular limitation except that a polyurethane foam is obtained by molding, and any operation such as preparation of a foaming stock solution and crushing treatment can be appropriately performed.
In addition, as a method for producing a polyurethane foam, a method of foaming and curing under atmospheric pressure, for example, on a belt conveyor or the like without using a mold may also be used. However, in such a method, since synthetic fibers have an adverse effect on foam molding and cells in the obtained polyurethane foam can be coarsened (for example, the cell diameter becomes 5 mm or more), it is necessary to control the fineness of the cells. It will be difficult.

(Automobile seat pad)
An automobile seat pad according to an embodiment of the present invention (hereinafter, may be referred to as “the seat pad of the present embodiment”) includes the above-described polyurethane foam for a seat pad. Since the seat pad of the present embodiment can be manufactured using the above-described polyurethane foam, it has high hardness and excellent vibration absorption and deformation prevention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are intended to illustrate the present invention and do not limit the present invention in any way.

(1) Preparation of Fibers The fibers shown below were prepared and cut using a fiber cutting machine so as to have the lengths shown in Table 1.
Rayon: Rayon fiber cut product 7.8T, manufactured by Chubu Pile Industry Co., Ltd.
Nylon 66: Nylon 66 fiber cut product manufactured by Chubu Pile Industry Co., Ltd. 6.7T

(2) Preparation of Polyurethane Foam 55 parts by mass of a polyether polyol (manufactured by Sanyo Chemical Industries, Ltd., “Sannicks FA703”) as a polyol component and 45 parts by mass of polymer polyol (manufactured by Sanyo Chemical Industries, Ltd., “Sannicks KC855”) 1 part by mass of a catalyst (including "TEDA-L33" manufactured by Tosoh Corporation) and 2 parts by mass of a cross-linking agent (diethanolamine manufactured by DOW) were mixed with a fiber having a material and a length shown in Table 1. Was added and mixed, and 1 part by mass of a foam stabilizer (manufactured by EVONIK, “B8742LF2”) and 2.5 parts by mass of a foaming agent (water) were blended to prepare a polyol composition. To this polyol composition was added tolylene diisocyanate (TDI) (manufactured by Mitsui Chemicals, Inc., “Cosmonate T-80”) and diphenylmethane diisocyanate (MDI) (manufactured by Tosoh Corporation, “MR-200HR”) as isocyanate components. 32 parts by mass of the mixture (mass of TDI: mass of MDI = 80: 20) were blended to prepare a foaming stock solution.
Next, using the prepared foaming stock solution, it was foamed and cured in a mold, and was demolded to obtain a polyurethane foam (soft polyurethane foam). The following evaluation and measurement were performed on the obtained polyurethane foam. Table 1 shows the results.
Comparative Example 1 is an example in which no fiber was added. Comparative Example 2 is an example in which the blending amount of the polymer polyol was reduced by 5 parts by mass (40 parts by mass) instead of adding the fiber. Comparative Example 3 is an example in which the amount of the foam stabilizer was increased by 0.2 parts by mass (1.2 parts by mass) instead of adding the fiber.

<Crash load>
The stress (unit: kgf) when the polyurethane foam immediately after the production was compressed at a compression ratio of 80% was measured with a crush roller to determine a first crush load. Further, the stress when the polyurethane foam was compressed at a compression ratio of 80% after 24 hours from the production was measured with a crush roller, and the final crush load was obtained. The higher the final crash load, the better the deformation prevention.

<Density>
The density (kg / m ³ ) was determined from the capacity of the cavity of the mold used and the weight of the obtained polyurethane foam.

<25% hardness>
Using an Instron type compression tester, a load (unit: kgf) required to compress the polyurethane foam by 25% in an environment of 23 ° C. and a relative humidity of 50% was measured as 25% hardness.

<Resonance magnification>
In accordance with JASO B 407, a 41 kg pressure plate was placed on a polyurethane foam sample, and the frequency was increased to 1 to 10 Hz. The transmissivity when the maximum transmissivity was shown was determined as the resonance magnification. The smaller the value of the resonance magnification, the better the vibration absorption.

From Table 1, it can be seen that the polyurethane foam of the example including the synthetic fiber having a predetermined length has a 25% hardness of 28.2 kgf or more, a final crash load of 47 kgf or more, and a resonance magnification of 3.86 or less. Was. That is, it can be seen that the polyurethane foams of the examples have high hardness, and also have excellent deformation preventing properties and vibration absorbing properties.
In Comparative Example 2, in order to weaken the foam breaking effect, the amount of the polymer polyol was reduced instead of adding the fiber. However, in Comparative Example 2, the hardness was reduced by 25%, and at least high hardness could not be achieved.
In Comparative Example 3, the amount of the foam stabilizer was increased in place of the addition of the fiber in order to increase the closed cell properties. However, in Comparative Example 3, the final crash load was low, and it was not possible to achieve at least high deformation prevention.

According to the present invention, it is possible to provide a polyurethane foam for a seat pad which has high hardness required for weight reduction of members, and is excellent in vibration absorption and deformation prevention. Further, according to the present invention, it is possible to provide a method for producing a polyurethane foam for a seat pad, which is capable of producing the polyurethane foam for a seat pad while suppressing cell coarsening. Further, according to the present invention, it is possible to provide an automobile seat pad which has high hardness and is excellent in vibration absorption and deformation prevention.

Claims (5)

1. (4) A polyurethane foam for a seat pad, comprising a synthetic fiber insoluble in water and having a length of 0.1 to 5 mm.
2. ポ リ ウ レ タ ン The polyurethane foam for a seat pad according to claim 1, wherein the synthetic fiber has a length of 0.5 to 2 mm.
3. The polyurethane foam for a seat pad according to claim 1 or 2, wherein the synthetic fiber is at least one selected from rayon fiber, nylon fiber, aramid fiber, polyethylene terephthalate fiber, and polyethylene naphthalate fiber.
4. 自動 車 A seat pad for an automobile, comprising the polyurethane foam for a seat pad according to any one of claims 1 to 3.
5. (4) A method for producing a polyurethane foam for a seat pad, comprising the step of obtaining the polyurethane foam for a seat pad according to any one of (1) to (3) by molding.