JP2022039004A - Cushion material for seat and seat - Google Patents

Abstract

To provide a cushion material for a seat which is excellent in riding comfort when travelling on an uneven road surface.SOLUTION: A cushion material for a seat comprises a foam of a composition containing polyol and diphenylmethane diisocyanate-based isocyanate. The foam has: a first region which has a hard segment and a soft segment, and of which Asker F hardness is 20 or more and less than 50 and permeability is 1 to 35 mL/cm2/sec; and a second region of which Asker F hardness is 50 or more and 70 or less and permeability is 1 to 35 mL/cm2/sec, and which is existent adjacent to the first region.SELECTED DRAWING: Figure 1

Description

The present invention relates to seat cushioning materials and seats.

The foam is used, for example, as a cushioning material. Further, as a cushion material, a cushion material having a portion having different hardness is known (see, for example, Patent Documents 1 to 4).

For example, Patent Document 1 discloses a laminated cushion body. This laminated cushion body is manufactured by inserting one or more partition plates into the mold, injecting different foaming raw materials into the mold with the partition plates as boundaries, and then pulling out the partition plates according to the foaming speed. ..
Patent Document 2 discloses a foamed cushion body having different hardness. In this different hardness foam cushion body, urethane foams having different hardness are at least directly bonded to each other through the openings of the heat-meltable synthetic resin film in which a large number of slits are opened by heating during foaming.
Patent Document 3 discloses a cushion body having different hardness in which portions having different hardness are formed. In this different hardness cushion body, the fibers of the fiber aggregates on the cotton in which the fibers are entwined three-dimensionally are bonded to each other by a urethane-based binder to form a cushion body, and the fiber aggregate is formed on a part of the cushion body. Is packed and combined with the binder.
Reference 4 is a reaction-cured product formed by using an isocyanate component of a diphenylmethane diisocyanate compound, which has urethane foam containing a hard segment and a soft segment, and the urethane foam is used in H1 solid ^- state pulse NMR measurement. In the ^first region where the spin-spin relaxation time (T2) of the hard segment is 30 μsec or more and 40 μsec or less and the volume existence ratio of the hard segment is 10% or more and 40% or less, and in the H1 solid-state pulse NMR measurement, it is hard. A second region in which the spin-spin relaxation time (T2) of the segment is 20 μsec or more and less than 30 μsec, and the volume abundance ratio of the hard segment is 5% or more and 40% or less, adjacent to the first region. A seat cushioning material with a second region present is disclosed.

Japanese Patent No. 60-21018 Japanese Unexamined Patent Publication No. 06-106627 Special Fair 04-034496 Gazette Japanese Unexamined Patent Publication No. 2019-107933

An object of the present invention is to provide a cushioning material for a seat and a seat having excellent riding comfort when traveling on an uneven road surface.

The above problem is solved by the following means. That is, it is a foam of a composition containing <1> a polyol and a diphenylmethane diisocyanate-based isocyanate.
It has a hard segment and a soft segment, and
In the first region, where the Asker F hardness is 20 or more and less than 50, and the air permeability is 1 to 35 mL / cm ² / sec.
For seats made of foam having an Asker F hardness of 50 or more and 70 or less, an air permeability of 1 to 35 mL / cm ² / sec, and a second region adjacent to the first region. Cushion material.
<2> The spin-spin relaxation time (T2) of the hard segment in the H ¹ solid-state pulse NMR measurement in the first region is 30 μsec or more and 40 μsec or less, and the volume existence ratio of the hard segment is 10% or more and 40% or less. And
The spin-spin relaxation time (T2) of the hard segment in the H1 solid ^- state pulse NMR measurement in the second region is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less. The cushion material for a seat according to <1>.
<3> The above <1> or <2> in which the isocyanate index (NCO INDEX) represented by the molar ratio (NCO group / active hydrogen group) of the isocyanate group to the active hydrogen group of the composition is 80 to 95. The listed seat cushioning material.
<4> The polyol is
Polycarbonate A0 having a weight average molecular weight of 200 to 10000 and a functional group number of 3
Containing polyol A1 having a weight average molecular weight of 1000 to 14000 and a functional group number of 4 to 5.
The seat cushion material according to any one of <1> to <3>, wherein the mass ratio of the polyol A0 to the polyol A1 (polypoly A0 / polyol A1) is 90/10 to 99/1.
<5> Any of the above <1> to <4>, wherein the isocyanate contains an isocyanate-terminated polyisocyanate which is a reaction product of a mixture of monomeric diphenylmethane diisocyanate and polypeptide diphenylmethane diisocyanate and a part of the polyol. Cushion material for seats described in one.
<6> The seat cushion material according to any one of <1> to <5>, wherein the seat cushion material is for a vehicle.
<7> The seat cushion material according to any one of <1> to <6>, wherein the seat cushion material is for a vehicle.
<8> The seat that supports the buttocks of the seated occupant,
The backrest that supports the back and waist of the seated occupant,
Equipped with
At least one of the seat portion and the backrest portion is a seat having the cushioning material for a seat according to any one of <1> to <7>.

According to the cushioning material of the present invention, there is provided a cushioning material for a seat and a seat having excellent riding comfort when traveling on a road surface having irregularities.

It is sectional drawing which shows an example of the cushion material for a seat which concerns on this embodiment. (A) is a perspective view showing an example of a pressure plate, and (B) is a cross-sectional view taken along the line AA in (A). It is a graph which shows an example of the compression-deflection curve schematically. It is a perspective view which shows an example of the seat of this disclosure. It is an exploded view which shows an example of the seat of this disclosure.

Hereinafter, embodiments that are an example of the present invention will be described. These descriptions and examples are illustrative of embodiments and do not limit the scope of the invention.
In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. good. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

The numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
The numerical range in which "greater than" or "less than" is added to the numerical values before and after "to" means a range in which these numerical values are not included as the lower limit value or the upper limit value.

Each component may contain a plurality of applicable substances.
When referring to the amount of each component in the composition, if there are multiple substances corresponding to each component in the composition, the total of the multiple substances present in the composition unless otherwise specified. Means quantity.

<Cushion material for seats>
The seat cushion material according to the present embodiment is composed of a foam having a composition containing a polyol and a diphenylmethane diisocyanate-based isocyanate.
The foam also has a hard segment and a soft segment.
Further, the foam has the following first region and the following second region existing adjacent to the first region.
First region: Asker F hardness is 20 or more and less than 50, and the air permeability is 1 to 35 mL / cm ² / sec.
Second region: Asker F hardness is 50 or more and 70 or less, and the air permeability is 1 to 35 mL / cm ² / sec.

The seat cushion material according to the present embodiment is used by arranging the first region on the seated occupant side and arranging the second region on the side away from the seated occupant side.

Here, an example of the cushion material for a seat according to the present embodiment will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a seat cushion material according to the present embodiment. The seat cushion material 100 is made of foam. The foam is a foam of a composition containing a polyol and a diphenylmethane diisocyanate-based isocyanate, and contains a hard segment and a soft segment. Further, in the seat cushion material 100, a first region 102 and a second region 104 are formed adjacent to the first region 102. In the seat cushion material 100, the boundary between the first region 102 and the second region 104 is not clearly formed. The first region is a region arranged on the seating surface side. Further, the second region is a region arranged on the side away from the seating surface.
In the present specification, the seating surface refers to a surface on the side that supports the buttocks and a surface that supports the back and waist when the occupant sits on the seat.

Further, the first region 102 and the second region 104 show the following characteristics.
First region 102: Asker F hardness is 20 or more and less than 50, and the air permeability is 1 to 35 mL / cm ² / sec.
Second region 104: Asker F hardness is 50 or more and 70 or less, and the air permeability is 1 to 35 mL / cm ² / sec.

In the seat cushion material 100, the boundary between the first region 102 and the second region 104 is ambiguous, but the boundary is not limited to this. The boundary between the first region 102 and the second region 104 may be ambiguous or may be clearly formed. Further, the cross-sectional shape of the seat cushion material 100 is not limited to the shape shown in FIG. 1, and may be formed in a shape suitable for the purpose. In the following description, the reference numerals will be omitted.

Conventionally, foam has also been applied to cushioning materials for seats for vehicles such as vehicles. The foam used as a cushioning material for a seat for a vehicle is required to improve the riding comfort while maintaining a flexible cushioning property at an appropriate foaming ratio (about 60 kg / m ³ ). To meet this demand, foams increase the abundance of hard segments in the foam.
Hard segments have a high melting point or high glass transition temperature. Therefore, the hard segment contributes to high modulus and high strength. The hard segment is a portion that expresses the strength of the foam in particular.

On the other hand, the soft segment has a glass transition temperature below room temperature (eg, 25 ° C.). Therefore, the soft segment contributes to high elongation and elastic recovery. The soft segment is the portion that develops the flexibility of the foam.

Here, the conventional foam is in the form of a large aggregate structure in which urea bonds are densely packed when the foam is a urethane foam (for example, when the foam is urethane foam) in the foam resin (the portion forming the skeleton and the film) of the foam. ) Is considered to be present in large proportion.

Further, in the conventional seat cushion material using foam, the hardness of the seat cushion material as a whole is high. It is considered that this is due to the existence of a large number of large aggregate structures in which urea bonds are densely packed. Therefore, when the seat cushion material using this foam is applied as the seat cushion material for a vehicle, it is difficult to disperse the load when the occupant sits down. As a result, this cushioning material for seats has a low flexible feel and body pressure dispersibility (fitting feeling), and further, a feeling of bottoming out and a feeling of foreign matter are likely to occur. In addition, this cushion material for seats is difficult to disperse vibration and has low vibration absorption. Therefore, the conventional cushioning material for seats using foam is inferior in riding comfort when traveling on a road surface having irregularities.

Here, for example, the cushioning materials disclosed in Patent Documents 1 to 3 are made of different raw materials and have different hardness portions, thereby improving the riding comfort. However, the different hardness cushioning materials disclosed in Patent Documents 1 to 3 do not sufficiently satisfy the required riding comfort characteristics when applied as a cushioning material for seats for vehicles, and there is room for further improvement. rice field. Further, since the cushioning materials having different hardness disclosed in Patent Documents 1 to 3 are manufactured by using different raw materials, they are disadvantageous in terms of equipment and labor.

On the other hand, the seat cushion material according to the present embodiment is a foam having a composition containing a polyol and a diphenylmethane diisocyanate-based isocyanate, and has a hard segment and a soft segment. The foam then has a first region and a second region adjacent to the first region. In each region, the Asker F hardness has the above-mentioned characteristics.

Since the asker F hardness of the seat cushion material according to the present embodiment has the above-mentioned characteristics, it is considered that the viscosity is dominant as a whole as compared with the conventional seat cushion material. Further, the Asker F hardness in the second region is higher than the Asker F hardness in the first region. Therefore, it is considered that the second region is more elastic than the first region.

The first region of the foam is a region arranged on the seating surface side (the side closer to the occupant) when the occupant is seated. Further, the second region of the foam is a region arranged on the side opposite to the seating surface side (the side away from the occupant).
Therefore, in the first region, by having the above-mentioned characteristics, the foam is expanded by the load when the occupant is seated, and the pressure is dispersed. Further, in the second region, by having the above-mentioned characteristics, it works to maintain the posture of the seated occupant. Therefore, the seat cushion material according to the present embodiment is excellent in a flexible feel, body pressure dispersibility, and vibration absorption, and a bottom thrust feeling and a foreign body feeling are suppressed. As a result, it is considered that the occupant seated on the seat cushion material according to the present embodiment feels that the ride quality is excellent.

On the other hand, the cushion material disclosed in Cited Document 4 is excellent in riding comfort on a smooth road surface, but further improvement in riding comfort when traveling on an uneven road surface has been required.

The foam constituting the seat cushion material according to the present embodiment has air permeability in both the first region and the second region of 1 to 35 mL / cm ² / sec. This means that the air permeability of both the first region and the second region of the foam is low. Therefore, the seat cushion material according to the present embodiment does not easily release the air in the foam even when the occupant is seated and receives a load. Therefore, since the state in which a large amount of air is contained in the foam is maintained, the impact absorption effect by the air is further enhanced. The seat cushion material according to the present embodiment is uneven due to the combination of the good ride quality due to the Asker F hardness having the above-mentioned characteristics and the shock absorbing effect due to the air permeability having the above-mentioned characteristics. It is possible to further soften the impact applied to the occupants when traveling on the road surface having the above.

From the above, it is presumed that the seat cushion material according to the present embodiment is excellent in riding comfort when traveling on an uneven road surface.

Here, when the central portion of the foam containing the first region and the second region is cut in the thickness direction, the ratio of the thickness of the first region and the second region of the foam to the cut surface. May be, for example, in the range shown below.
Ratio (h1 / h0) of the thickness (h1) of the first region to the total thickness (h0) of the foam: 5% or more and 35% or less The thickness of the second region (h2) to the total thickness (h0) of the foam Ratio (h2 / h0): 65% or more and 95% or less

In the present disclosure, the first region and the second region are separated for convenience as follows.
From the outer surface corresponding to the first region of the foam including the first region and the second region, the surface is cut at an arbitrary position toward the second region in a plane perpendicular to the thickness direction. Among the cut foams, the Asker F hardness on the cut surface of the foam including the second region is measured. By the same procedure, the cutting of the foam and the measurement of the Asker F hardness on the cut surface are repeated, and the Asker F hardness on each cut surface is measured. The region where the Asker F hardness is less than 50 is defined as the first region. Further, the region where the Asker F hardness is 50 or more is defined as the second region.

Hereinafter, the details of the seat cushion material according to the present embodiment will be described.

(Composition)
The composition comprises a polyol and a diphenylmethane diisocyanate-based isocyanate.

-Polyol-
The polyol is not particularly limited.
As the polyol, a polyether polyol that is difficult to hydrolyze is preferable in that the seat cushion material according to the present embodiment may be applied to a vehicle seat (particularly a vehicle seat).

Specific examples of the polyether polyol include a polyether polyol obtained by addition-polymerizing an alkylene oxide (ethylene oxide, propylene oxide, etc.) with an alcohol. The addition polymerization of a plurality of types of alkylene oxides may be random addition polymerization or block addition polymerization.

The average molecular weight of the polyol is preferably 200 to 20000, more preferably 200 to 16000, and even more preferably 200 to 15000 in terms of weight average molecular weight.

The polyol includes a polyol A0 having a weight average molecular weight of 200 to 10000 and a functional group number of 3, and a polyol A1 having a weight average molecular weight of 1000 to 14000 and a functional group number of 4 to 5. The mass ratio of A0 to the polyol A1 (polypoly A0 / polyol A1) is preferably 90/10 to 99/1.
When the polyol contains the polyol A0 and the polyol A1 in the above ratio, a foam having a lower air permeability can be obtained. As a result, it is possible to obtain a cushion material for a seat having an excellent ride quality when traveling on a road surface having further irregularities.

Specific examples of the polyol A0 include a polyether polyol obtained by addition-polymerizing an alkylene oxide (ethylene oxide, propylene oxide, etc.) to a trihydric alcohol.
The weight average molecular weight of the polyol A0 is more preferably 2000 to 8000, and further preferably 4000 to 7000.

Specific examples of the polyol A1 include a polyether polyol obtained by addition-polymerizing an alkylene oxide (ethylene oxide, propylene oxide, etc.) to a 4- to pentahydric alcohol.
The weight average molecular weight of the polyol A1 is more preferably 1100 to 13000, and even more preferably 1150 to 12500.

The mass ratio of the polyol A0 to the polyol A1 (polypoly A0 / polyol A1) is more preferably 90/10 to 97/3, and even more preferably 90/10 to 93/7.

-Diphenylmethane diisocyanate-based isocyanate-
First, a diphenylmethane diisocyanate-based isocyanate will be described. Hereinafter, diphenylmethane diisocyanate may be referred to as "MDI".
The MDI-based isocyanate is not particularly limited. For example, pure (pure) diphenylmethane diisocyanate (monomeric MDI), polypeptide MDI, mixtures containing monomeric MDI and polypeptide MDI, isocyanate-terminated polyisocyanates of polypeptide MDI, and isocyanate ends containing monomeric MDI and polypeptide MDI. Examples include modified polyisocyanates.

Specifically, for example, 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4). '-MDI), and a monomeric MDI of a mixture thereof; a polymeric MDI of a polymethylene polyphenylene polyisocyanate; a mixture of a monomeric MDI and a polymeric MDI; an isocyanate end-modified polyisocyanate obtained by reacting the monomeric MDI with a part of a polyol. An isocyanate-terminated polyisocyanate in which a polypeptide MDI is reacted with a part of a polyol; an isocyanate-terminated polyisocyanate in which a mixture of a monomeric MDI and a polypeptide MDI is reacted with a part of a polyol; a monomeric MDI is a part of a polyol. A mixture of an isocyanate-terminated polyisocyanate reacted with and an isocyanate-terminated polyisocyanate in which a polypeptide MDI is reacted with a part of a polyol; an isocyanate in which a mixture of a monomeric MDI and a polypeptide MDI is reacted with a part of a polyol. Examples thereof include a mixture in which a terminal-modified polyisocyanate contains at least one of a monomeric MDI and a polypeptide MDI; and the like. These MDI-based isocyanates may be used alone or in combination of two or more.

Among these, MDI-based isocyanates are a mixture of monomeric MDI and polymer MDI and polyols in that they improve the riding comfort of the seat cushioning material when traveling on uneven road surfaces. It is preferable to contain an isocyanate-terminated polyisocyanate (that is, a prepolymer obtained by reacting a mixture of a monomeric MDI and a polypeptide MDI with a part of a polyol) which is a reaction product of a part thereof. Further, it is more preferable that the isocyanate-terminated polyisocyanate is obtained by reacting a mixture of monomeric MDI and polypeptide MDI with a part of the polyol. When this isocyanate-terminated polyisocyanate is used, it becomes easy to suppress the formation of an aggregate structure of urea bonds.

In isocyanate-terminated polyisocyanate in which a mixture of monomeric MDI and polypeptide MDI is reacted with a part of a polyol, the mixing ratio (mass ratio) of monomeric MDI and polypeptide MDI is the mass ratio of monomeric MDI to the mass of polypeptide MDI. The mass ratio (monomeric MDI / polymeric MDI) is preferably in the range of 30/70 or more and 90/10 or less. More preferably, it is in the range of 32/68 or more and 85/15 or less. When the MDI mixture ratio (mass ratio) of the monomeric MDI and the polymeric MDI is in the range of 30/70 or more and 90/10 or less, it is possible to prevent the foam from deviating from the characteristics as a seat cushion material. Further, the deterioration of moldability is suppressed.

Further, the isocyanate-terminated polyisocyanate obtained by reacting a mixture of monomeric MDI and polypeptide MDI with a part of the polyol can be adjusted so that the NCO content (% by mass) is finally 10 or more and 30 or less. preferable.

If the desired foam is obtained, the composition may contain an isocyanate other than the MDI-based isocyanate as long as it does not affect the riding comfort when traveling on a road surface having irregularities.

-catalyst-
The composition usually contains a catalyst.
The catalyst is not particularly limited, and various urethanized catalysts known in the field of urethane foam used as a cushioning material for seats can be used. For example, triethylamine, triethyldiamine, tripropylamine, tributylamine, N-methylmoriphorin, N-ethylmoriphorin, dimethylbenzylamine, N, N, N', N'-tetramethylhexamethylenediamine, N, N, N', N', N''-pentamethyldiethylenetriamine, bis- (2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo (5,4,0) undecene-7,1,2- Amine-based catalysts of amine compounds such as dimethylimidazole, dimethylethanolamine, N, N-dimethyl-N-hexanolamine; organic acid salts of these amine compounds; stanas octoate; organic metal compounds such as zinc naphthenate can be mentioned. .. Further, an amine-based catalyst having active hydrogen such as N, N-dimethylethanolamine, N, N-diethylethanolamine; can also be mentioned. These catalysts may be used alone or in combination of two or more.

The amount of the catalyst added is preferably 0.01% by mass or more and 10% by mass or less with respect to the polyol component. When it is 0.01% by mass or more, the lack of cure is easily suppressed, and when it is 10% by mass or less, the deterioration of moldability is suppressed.

-Effervescent agent-
The foaming agent is often a foaming agent containing water, and water alone is preferable.
The amount of water used as the foaming agent may be set according to the target foaming ratio with respect to 100 parts by mass of the polyol component.
When the foaming agent is used in combination with water, examples of the foaming agent other than water include methylene chloride, hydrochlorofluorocarbons (HCFC-123, etc.), hydrofluorocarbons (HFC-245fa, etc.), butane, pentane (cyclopentane, etc.). , Isopentane, normal pentane) and the like; organic acids such as formic acid; and the like.
Further, as the foaming agent, in addition to the foaming agent containing water, air, nitrogen gas, liquefied carbon dioxide and the like may be mixed and dissolved in the mixed raw material for obtaining the foam. The amount of the foaming agent other than water may be set according to the target foaming ratio.

-Other ingredients-
Other components are components (additives) that are added as needed. Examples of other components include cross-linking agents, colorants, fillers, flame retardants, antioxidants, ultraviolet absorbers, antistatic agents, defoaming agents and the like. When other components are used, one of them may be used alone, or two or more of them may be selected and used as necessary.

-Mole ratio of isocyanate group to active hydrogen group-
The isocyanate index (NCO INDEX) represented by the molar ratio (NCO group / active hydrogen group) of the isocyanate group to the active hydrogen group of the composition is not particularly limited. The isocyanate index is preferably, for example, 80 to 95, more preferably 85 to 93, and 87 to 92 in terms of obtaining a better ride quality when traveling on an uneven road surface. It is more preferable to have.
Here, the isocyanate index is a percentage of the value obtained by dividing the number of moles of isocyanate groups in the composition by the total number of moles of active hydrogen groups capable of reacting with isocyanate groups (hydroxyl group of polyol, water as a foaming agent, etc.). Desired.
In the present specification, the isocyanate index represents a value when a composition for obtaining a foam containing a polyol, a diphenylmethane diisocyanate-based isocyanate, and a component capable of reacting with an isocyanate component is reacted. .. Therefore, it does not represent the isocyanate index when obtaining the isocyanate-terminated modified polyisocyanate.

(Foam)
Hereinafter, the details of the foam constituting the seat cushion material according to the present embodiment will be described.
The foam is composed of a foam obtained by foaming the above-mentioned composition.

-Asker F hardness-
The foam has an Asker F hardness of 20 or more and less than 50 in the first region, and an Asker F hardness of 50 or more and 70 or less in the second region.
When the Asker F hardness in each region is in the above range, the riding comfort when traveling on a road surface having irregularities is excellent. It is considered that the Asker F hardness in the first region and the second region is caused by, for example, the size of the urea-bound aggregate and the amount of the urea-bound aggregate.

From the viewpoint of excellent riding comfort when traveling on an uneven road surface, the lower limit of the Asker F hardness in the first region is preferably 25 or more, and more preferably 30 or more.
Further, from the viewpoint of excellent riding comfort when traveling on a road surface having irregularities, the upper limit of the Asker F hardness in the first region is preferably 45 or less, and more preferably 40 or less.

From the viewpoint of excellent riding comfort when traveling on an uneven road surface, the upper limit of the Asker F hardness in the second region is preferably 60 or less, more preferably 55 or less.

When the Asker F hardness in the first region is F1 and the Asker F hardness in the second region is F2, the absolute value of the difference between F1 and F2 (| F1-F2 |) is 10 or more and 50 or less. good. The absolute value of the difference between F1 and F2 may be 10 or more and 45 or less, or 10 or more and 40 or less.
When the absolute value of the difference in Asker F hardness in each region is within the above range, the ride quality is excellent.

As a method for measuring the Asker F hardness, an ASKER hardness tester F type is used, and the surface hardness of the foam to be measured is measured under a temperature condition of 21 ± 2 ° C.
For the Asker F hardness, install an Asker hardness tester F type on the surface at the positions shown below for the parts in the first region and the second region of the foam to be measured, and read the value after 20 sec. To measure.
First region: The outer surface corresponding to the first region of the foam is measured.
Second region: Measure a position 15 mm from the outer surface corresponding to the second region of the foam toward the first region (for example, the surface by slicing every 5 mm).

-Breathability-
The foam has an air permeability of 1 to 35 mL / cm ² / sec in the first region and the second region.
The cushioning material for a seat made of a foam having a breathability in the above range in each region has a higher impact absorbing effect due to air, and is excellent in riding comfort when traveling on an uneven road surface.

The air permeability in the first region and the second region is preferably 5 to 30 mL / cm ² / sec, more preferably 10 to 28 mL / cm ² / sec, and 15 to 27 mL / cm ² / sec. It is more preferably sec.

Here, the air permeability is measured by the following procedure.
A sample cut out from each of the first region and the second region according to the following procedure is measured according to JIS K6400-7.
The method of cutting out a sample from each of the first region and the second region will be described below.
For the measurement of the first region, a measurement sample having a length of 150 mm, a width of 150 mm and a thickness of 5 mm is cut out from the first region and used as a sample for air permeability measurement.
For the measurement in the second region, a measurement sample having a length of 150 mm, a width of 150 mm, and a thickness of 5 mm is cut out from the second region and used as a sample for air permeability measurement.
The sample cut out from the first region contains only the first region, and the sample cut out from the second region includes only the second region.

-H ¹ solid-state pulse NMR measurement-
In the first region and the second region, it is preferable that the spin-spin relaxation time (T2) of the hard segment and the volume existence ratio of the hard segment in the H1 solid ^- state pulse NMR measurement are as follows.
First region: In the H ¹ solid-state pulse NMR measurement, the spin-spin relaxation time (T2) of the hard segment is 30 μsec or more and 40 μsec or less, and the volume existence ratio of the hard segment is 10% or more and 40% or less.
Second region: In the H1 solid ^- state pulse NMR measurement, the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less.

Here, when the spin-spin relaxation time (T2) of the hard segment in the H1 solid-state pulse NMR measurement of the ^first region and the second region is within the above range, the first region and the second region are , May be carved as follows.
A measurement sample is taken in the thickness direction from the central portion of the foam containing the first region and the second region. The spin-spin relaxation time (T2) of the collected test piece is measured according to the H1 solid ^- state pulse NMR measurement shown below. Then, among the measurement samples collected in the thickness direction, the region where the spin-spin relaxation time (T2) is 30 μsec or more is defined as the first region. Further, a region in which the spin-spin relaxation time (T2) is less than 30 μsec is defined as a second region.

Here, the spin-spin relaxation time (T2) and the volume abundance ratio in H ¹ solid-state pulse NMR (Nuclear Magnetic Resonance) measurement will be described.

First, H ¹ solid-state pulse NMR measurement will be described. In the present specification, the H1 solid ^- state pulse NMR measurement is performed by vacuum-drying the foam to be measured at room temperature all day and night, vacuum-sealing it as a test piece, and measuring it in a vacuum at 25 ± 1 ° C. be. Specific measurement conditions are shown below.
The measured temperature of 25 ± 1 ° C. indicates that an error is allowed up to a range of ± 1 ° C. with respect to 25 ° C. Hereinafter, the meaning of "±" means the same meaning (that is, an error up to the numerical value described on the right side is allowed based on the numerical value described on the left side of ±).

-Measurement condition-
Measuring device: JEM-MU25 (resonance frequency 25 MHz) manufactured by JEOL Ltd.
Measurement method: Solid echo method Measurement temperature: 25 ± 1 ° C
Pulse width: 90 ° pulse, 2.3 μs
Repeat time: 4 sec
Accumulation number: 32 times (foam sample)
The analysis results (spin-spin relaxation time (T2) and volume existence ratio of the hard segment) are based on the premise that the value of the Variance variance is 25 or less. The Variance variance indicates the degree of data dispersion and is expressed as the average of the squares of the deviations.

The test piece for measuring the first region is collected by cutting a slice every 5 mm from a portion including an outer surface (for example, the surface on the bottom side of the mold) corresponding to the first region of the foam. Then, among the collected test pieces, the surface of the foam on the outer surface side is measured.
Further, the test piece for measuring the second region is a portion 15 mm from the outer surface corresponding to the second region of the foam toward the first region (for example, from the upper side of the mold toward the bottom side of the mold). Slices are excised every 5 mm, and a test piece containing (15 mm site) is collected. Then, among the collected test pieces, the position of 15 mm from the outer surface corresponding to the second region of the foam toward the first region is measured.

In the H1 solid ^- state pulse NMR measurement, the amount of components of the object to be measured can be evaluated by utilizing the difference in relaxation time.
When the measurement object is subjected to H1 solid ^- state pulse NMR measurement, a FID signal (free induction decay) is obtained as a response to the pulse. The initial value of the FID signal is proportional to the number of protons in the measurement sample. When the object to be measured has a plurality of components such as a hard segment and a soft segment, the FID signal is the sum of the response signals of each component. If there is a difference in motility depending on the component, the spin-spin relaxation time (T2) will be different. Therefore, by separating the spin-spin relaxation time (T2), the relaxation time of each component and the ratio of each component (volume existence ratio) can be obtained. The smaller the motility of the component, the shorter the spin-spin relaxation time (T2), and the larger the motility, the longer the spin-spin relaxation time (T2). That is, the harder the component, the shorter the spin-spin relaxation time (T2), and the softer the component, the longer the spin-spin relaxation time (T2).

When a foam having a hard segment and a soft segment is measured, in the H1 solid ^- state pulse NMR measurement, the spin-spin relaxation time (T2) of the hard segment and the soft segment is different due to the difference in motility. .. The hard segment has a shorter spin-spin relaxation time (T2), and the soft segment has a longer spin-spin relaxation time (T2). That is, the spin-spin relaxation time (T2) becomes shorter as the urea-bonded aggregate structure is formed, and the spin-spin relaxation time (T2) becomes longer as the formation of the urea-bonded aggregate structure is suppressed. Become.
Further, the larger the volume existence ratio of the hard segment (that is, the more the aggregate structure of urea bonds is formed), the shorter the spin-spin relaxation time (T2).

From the above, in the H1 solid-state pulse NMR measurement in vacuum at 25 ± ¹ ° C., the spin-spin relaxation time (T2) of the hard segments in the first region and the second region is within the above range. , It is considered to mean that there are few hydrogen bonds between urea bonds in the aggregate structure of urea bonds in the foam (that is, there are few large aggregate structures in which urea bonds are densely packed).

In particular, in the first region, the spin-spin relaxation time (T2) of 30 μsec or more and 40 μsec or less is considered to indicate the existence of urea bonds in a state close to monodisperse.
Further, it is considered that the spin-spin relaxation time (T2) of 20 μsec or more and less than 30 μsec in the second region is more likely to form an aggregate structure in which urea bonds are densely formed than in the first region. Be done. On the other hand, urea-bound aggregates are considered to exist in a small state.

The volume abundance ratio of the hard segment in the first region is in the range of 10% or more and 40% or less, and the volume abundance ratio of the hard segment in the second region is in the range of 5% or more and 40% or less. It is considered that the structure is suppressed in that the abundance ratio of hydrogen bonds between urea bonds in the structure is small (that is, the number of aggregate structures in which urea bonds are dense) is small.

From the above, when the spin-spin relaxation time (T2) and the volume existence ratio of the first region are within the above ranges, the viscosity of the first region is more likely to become dominant.
Further, when the spin-spin relaxation time (T2) and the volume existence ratio of the second region are within the above ranges, the second region is more likely to be in a state where elasticity is dominant than the first region. ..
As a result, the seat cushion material made of foam having the spin-spin relaxation time (T2) and the volume existence ratio in the first region and the second region within the above ranges becomes more comfortable to ride. Cheap.

-Physical characteristics-
The foam may have the following physical properties, for example.

-Density The density of the foam may be, for example, 55 to 65 kg / m ³ .
The density of the foam is measured according to JIS K 7222 (2005).

Moist heat compression permanent strain The moist heat compression permanent strain is a measurement of the compression permanent strain after 50% compression for 22 hours under the conditions of a temperature of 50 ° C. ± 2 ° C. and a relative humidity of 95%.

The foam may have, for example, a wet heat compression permanent strain of 1% or less. It is preferably 0.8% or less, more preferably 0.5% or less.
The fact that the wet-heat compression permanent strain is 1% or less means that the compression permanent strain over time under moist-heat conditions is suppressed to a low level. Therefore, it is shown that when the seat cushion material according to the present embodiment is applied to, for example, a vehicle seat cushion material, a more stable and excellent ride quality can be obtained over time.
The smaller the wet heat compression permanent strain, the better the ride quality over time. Therefore, the lower limit value of the wet heat compression permanent strain is preferably 0%, but the lower limit value is not particularly limited.

The procedure for measuring the wet-heat compression permanent strain will be described below.
A test piece having a length of 380 mm and a width of 380 mm (thickness is the thickness of the foam) is cut out from the foam to be measured. The thickness (t0) of this test piece is measured, compressed to 50% of the thickness of the test piece, fixed, and left in a high humidity constant temperature bath at 50 ° C. ± 2 ° C. and a relative humidity of 95% for 22 hours. Then, the fixed test piece is taken out, and the thickness (t1) of the test piece after 30 minutes is measured. After that, the value obtained by the following formula is used as the value of the wet heat compression permanent strain.
(Equation) Wet heat compression permanent strain (%) = {(t0-t1) / t0} × 100

Moist heat compression set (compressive set after 50% compression for 22 hours under conditions of temperature 50 ° C ± 2 ° C and relative humidity 95%) provides, for example, a realistic usage environment for vehicle seats. Reflecting this, it is known as a reliability test over time under conditions under which moist heat is applied at the same time as the compressive load. For moist heat compression permanent strain, changes in vibration absorption, impact resilience, bottoming feeling, etc. can be expected by measuring the final thickness change (permanent strain) of the seat cushion material. That is, the moist heat compression permanent strain is an index that can know the influence on the ride quality over time when the seat cushion material is applied to the seat for a vehicle.

As an index showing the ride quality of the seat cushion material over time, it is desirable that the wet heat compression permanent strain is small.

・ 25% hardness (ILD)
The 25% hardness (ILD) of the foam is preferably, for example, 180-500 N / 314 cm ² .
The 25% hardness (ILD) is measured according to JIS K-6400 (1997) for the foam obtained by foaming to a thickness of 100 mm.

-Hysteresis loss The hysteresis loss of the foam is an index of the body pressure dispersibility, the bottom thrust feeling, and the foreign body feeling of the cushion material for the seat. The range of the hysteresis loss is not particularly limited, and may be, for example, 8% or more and 20% or less.

Hysteresis loss is a value obtained by the compression deflection test. Hysteresis loss is calculated from the compression-deflection measurement curve by the constant load compression method according to JIS K6400-2 (2012).
Specifically, a test piece having a length of 380 mm and a width of 380 mm (thickness is the thickness of the foam) is cut out from the foam to be measured and used as a measurement sample. Next, at room temperature (21 ± 2 ° C; the room temperature in the following measurements is 21 ± 2 ° C), a pressure plate (iron laboratory plate: see FIGS. 2 (A) and 2 (B), dimensions; W1: 300 mm. , W2: 250 mm, R1: 125 mm, R2: 30 mm, H: 50 mm), and the thickness when a load is applied in the vertical direction at 10 mm / min and pressed at 4.9 N is defined as the initial thickness. After determining the initial thickness, it is compressed and flexed at a compression rate of 150 mm / min until the maximum load is 980 N. Next, the pressure plate is returned to the initial thickness at the same speed and left for 1 minute for precompression. After 1 minute, the pressure plate is again compressed and flexed at a compression rate of 150 mm / min to a maximum load of 980 N. After that, the pressure plate is returned to the initial thickness at the same speed, and the measurement history is shown in a graph (see FIG. 3).

FIG. 3 is a graph schematically showing an example of a compression-deflection curve. The hysteresis loss is surrounded by the origin 0-curve A-point B-curve C-point D with respect to the area 0ABE0 of the region surrounded by the origin 0-curve A-point B-point E-origin 0 in the graph shown in FIG. It is expressed as a percentage (%) of the area of 0 ABCD in the area, and is calculated by the following formula.
(Equation) Hysteresis loss Af = ((Area 0ABCD / Area 0ABE0) × 100)
In FIG. 3, the horizontal axis DR (%) represents the deflection rate (%), and the vertical axis L (N) represents the load.

-Logarithmic decrement The logarithmic decrement of the foam is an index of the vibration absorption of the cushion material for seats. The logarithmic decrement is originally a parameter for evaluating the damping property of a material, and the larger this value is, the higher the vibration damping performance is. Therefore, the cushioning material for a seat made of a foam having a high value tends to be, for example, a cushioning material for a seat having an excellent ride quality when traveling on a road surface having irregularities.

Further, from the viewpoint of providing a cushioning material for a seat having excellent riding comfort when traveling on an uneven road surface, the logarithmic decrement rate is preferably, for example, 3.00 to 9.00, and 3.50 to 8 It is more preferably .50, and even more preferably 4.00 to 8.00.

The logarithmic decrement is measured in accordance with JIS K6394 (2007). Specifically, the logarithmic decrement is obtained by dividing the logarithmic decrement (Λ) by 2π in the damped vibration waveform on the response side obtained by the vibration test at room temperature. The logarithmic decrement (Λ) is determined by taking the natural logarithm of the ratio of heights An of adjacent amplitudes (An / An + 1).
Further, in general, the value of the attenuation factor has a different value for each natural vibration mode called the first natural mode, the second natural mode, and the like in order from the one with the smallest frequency.
Therefore, the logarithmic decrement rate is measured by measuring the target foam as follows. In the foam constituting the seat cushion material according to the present embodiment, the damping rate average value is calculated from the average value of the damping rates of a plurality of unique modes appearing in the frequency range of 0 Hz or more and 500 Hz or less, and is a representative showing the vibration damping performance. Use as a value. The method for determining the attenuation rate is as follows. First, the transfer function (ratio of the input vibration force and the output response) is obtained from the vibration test results. Then, the obtained function value is calculated by a curve matching method to calculate the attenuation rate for each mode. By this arithmetic processing, the natural frequency for each mode can also be calculated.

Regarding the logarithmic decrement, the measurement positions of the foam to be measured are as follows.
For the measurement of the first region, a measurement sample having a length of 100 mm, a width of 100 mm, and a thickness of 40 mm is cut out from the first region and used as a sample for air permeability measurement.
For the measurement in the second region, a measurement sample having a length of 100 mm, a width of 100 mm, and a thickness of 40 mm is cut out from the second region and used as a sample for air permeability measurement.
The sample cut out from the first region contains only the first region, and the sample cut out from the second region includes only the second region.
Then, the logarithmic decrement is measured by applying a load to the cut surface on the first region side of the measurement sample. The arithmetic mean of the measured values in the first region and the measured values in the second region is defined as the logarithmic decrement of the foam.

(Manufacturing method of foam)
The method for producing the foam is not particularly limited, and known methods in the slabstock method and the molding method for molding in a mold can be applied.
As an example of a preferable method for producing a foam, for example, a first step of preparing an MDI-based isocyanate, a second step of forming a composition in which the above-mentioned MDI-based isocyanate and a polyol are mixed, and the above-mentioned Examples thereof include a method comprising a third step of obtaining a foam by foaming the composition.

In the first step, for example, a polyisocyanate prepared by mixing a mixture of monomeric MDI and polypeptide MDI with a part of a polyol in advance (that is, a mixture of monomeric MDI and polypeptide MDI is used as a part of a polyol). It is preferable to prepare a reacted isocyanate terminal-modified polyisocyanate).
The mixture of monomeric MDI and polypeptide MDI may have a mixing ratio of monomeric MDI / polypeptide MDI of 30/70 or more and 90/10 or less (mass ratio). Further, it is preferable to adjust the isocyanate group (NCO group) so that the NCO content (% by mass) is finally 10 or more and 30 or less.
Further, from the viewpoint of obtaining a foam having low air permeability, the polyol used for preparing the isocyanate-terminated polyisocyanate has a weight average molecular weight of 200 to 10,000, and a weight average molecular weight of polyol A0 having 3 functional groups. It contains a polyol A1 having 1000 to 14000 and having 4 to 5 functional groups, and the mass ratio of the polyol A0 to the polyol A1 (polyol A0 / polyol A1) is 90/10 to 99/1. Is preferable.
The mixture of monomeric MDI and polypeptide MDI is not limited to the isocyanate-terminated modified polyisocyanate obtained by reacting with a part of the polyol, and the above-mentioned MDI-based isocyanate may be used.

In the second step, a composition containing the MDI-based isocyanate and the polyol prepared in the first step is molded.
Hereinafter, as the MDI-based isocyanate in the first step, a case where an isocyanate-terminated polyisocyanate obtained by reacting a mixture of monomeric MDI and polyvinyl MDI with a part of the polyol will be described.
Here, from the viewpoint of obtaining a foam having a low air permeability, the polyol in the composition is preferably the same as the polyol used for preparing the above-mentioned isocyanate-terminated polyisocyanate.
Further, from the viewpoint of obtaining a foam having low air permeability, the isocyanate index (NCO INDEX) represented by the molar ratio (NCO group / active hydrogen group) of the isocyanate group to the active hydrogen group of the composition is 80 to 95. Is preferable.

As a third step, a case of molding by a molding method of molding in a mold will be described.
In the third step, a foam is obtained by injecting the above composition into a mold and foaming it in a mold at a predetermined temperature.
In general, from the injection of raw materials into the mold until just before the reaction starts, the one with a relatively large molecular weight is easier to move toward the bottom of the mold, the smaller the molecular weight is, and the more active the molecular motion is, the more from the bottom of the mold. There is a tendency for the reaction to proceed easily while shifting to the distant upper surface side of the mold.
When the composition using the above isocyanate-terminated polyisocyanate is injected into the mold, a region having a high presence ratio of the isocyanate-terminated polyisocyanate mainly containing polypeptide MDI is formed in the region on the bottom side of the mold. Conceivable. On the other hand, in the region on the upper surface side of the mold, it is considered that a region in which the abundance ratio of the isocyanate-terminated polyisocyanate mainly containing monomeric MDI is high is formed.

The isocyanate-terminated polyisocyanate mainly containing polymeric MDI has a slow molecular motion and a short motion distance, and therefore has poor reactivity. As a result, it is considered that small urea-bonded aggregates are unlikely to be formed in the region on the bottom side of the mold, and urea-bonds are likely to exist alone.
On the other hand, the isocyanate-terminated polyisocyanate mainly containing monomeric MDI has high reactivity because the molecular motion is active and the motion distance is long. As a result, it is considered that small urea-bound aggregates are more likely to be formed in the region on the upper surface side of the mold than in the region on the bottom side of the mold.

The temperature of the mold for foaming is preferably in the range of 30 ° C. or higher and 50 ° C. or lower (a preferable lower limit is 35 ° C. or higher, and a preferable upper limit is 45 ° C. or lower). When the temperature of the mold mold is in this range, the molecular motion is slow and the reactivity with water is poor in the region on the bottom side of the mold. Therefore, the rate of urea bond formation is slow. Further, even if a urea bond is generated, it is difficult to form a urea bond aggregate. Then, the urea bond tends to be monodisperse.
On the other hand, in the region on the upper side of the mold, the reaction is accompanied by an exothermic reaction with water. Therefore, the reactivity becomes more active than the region on the bottom side of the mold, and small urea-bound aggregates are likely to be formed.

As a result, in the obtained foam, in the region on the bottom side of the mold, the spin-spin relaxation time (T2) of the hard segment was 30 μsec or more and 40 μsec or less in the H1 solid-state pulse NMR measurement at 25 ± ¹ ° C. The volume existence ratio of the hard segment is 10% or more and 40% or less, and the Asker F hardness can be easily controlled in the range of 20 or more and less than 50.
Further, in the region on the upper surface side of the mold, the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec in the H1 solid-state pulse NMR measurement at 25 ± ¹ ° C., and the volume existence ratio of the hard segment is 5. % Or more and 40% or less, and the Asker F hardness can be easily controlled in the range of 50 or more and 70 or less. That is, the region on the bottom side of the mold becomes the first region, and the region on the upper surface side of the mold adjacent to the first region becomes the second region.
As described above, according to the above-mentioned preferable manufacturing method, a foam having regions showing different characteristics can be obtained with a single raw material, so that a cushioning material for a seat having excellent riding comfort can be obtained. Furthermore, cost improvement is expected.

When the temperature of the mold mold during foam molding exceeds 50 ° C (for example, 60 ° C or higher), a skin containing a urea-bonded aggregate structure on the surface of the foam in contact with the mold in the mold. Layers are more likely to be formed. Therefore, the ride quality tends to decrease. If the temperature is lower than 30 ° C, it becomes difficult to produce the foam.

In the second step, the composition is prepared by mixing the polyol with the catalyst and the foaming agent in advance (premix) and then mixing with the MDI-based isocyanate prepared in the first step. You may. Further, the MDI-based isocyanate prepared in the first step, the catalyst, the foaming agent, and the polyol may be mixed, respectively.

Further, in the foam manufacturing method, when water is present in the foam manufacturing environment in all the steps of the first step and the second step, the MDI-based isocyanate reacts with the water to form a urea bond. It is more likely to occur. Therefore, it is preferable to manufacture the foam in a nitrogen purge atmosphere in all the steps of the foam manufacturing process. Under a nitrogen purge atmosphere, the formation of urea-bound aggregate structures is likely to be suppressed.

In the present specification, the term "process" is used not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. include.

(Use)
The seat cushion material according to the present embodiment is suitable as a cushion material for vehicles (ships, aircraft, vehicles, virtual reality devices, etc.) because it has excellent ride quality. Above all, it is more preferable to apply it to a cushioning material for a seat for a vehicle. Examples of seats for vehicles include seats for each vehicle, such as automobile and railroad seats. Other examples include seats for vehicles such as cultivators, tractors, excavators, hydraulic cranes, excavators, and bicycles. In particular, it is preferably applied to seats for automobiles. In addition, it may be applied to cushioning materials for seats used in facilities such as theaters and movie theaters.

<Seat>
Next, an embodiment to which the seat cushion material according to the present embodiment is applied will be described.

The seat according to the present embodiment includes a seat portion that supports the buttocks of the seated occupant, and a backrest portion that supports the back portion and the waist portion of the seated occupant. Then, at least one of the seat portion and the backrest portion has the seat cushion material according to the present embodiment. In the seat cushion material according to the present embodiment, the first region of the foam is arranged on the seating surface (that is, the seated occupant side).

Here, the seat cushion material according to the present embodiment may be applied to both the seat portion and the backrest portion, or may be applied to either the seat portion or the backrest portion. The seat cushion material according to the present embodiment is preferably applied to at least the seat portion. The seat cushion material according to the present embodiment may be applied to a part of the seat portion.

Hereinafter, an example of the seat according to the present embodiment will be described with reference to the drawings.
FIG. 4 is a perspective view showing an example of a seat according to the present embodiment. The seat 200 shown in FIG. 4 is represented as an example of an automobile seat. As shown in FIG. 4, the seat 200 is a seat used in the front row of the vehicle. The seat 200 includes a seat portion 202 that supports the buttocks of the seated occupant, and a backrest portion 204 that supports the back and waist of the seated occupant. The surface of the seat portion 202 has a cushion skin 18, and the surface of the backrest portion 204 has a back skin 20. Further, the seat 200 (hereinafter referred to as "seat 200") includes a headrest 22 that supports the head of the occupant.

FIG. 5 is an exploded view showing an example of a seat according to the present embodiment. FIG. 5 shows an exploded view of the sheet 200 shown in FIG. As shown in FIG. 5, the seat 200 includes a frame 12 as a support, a seat cushion 14 attached to the frame 12, a seat back 16 attached to the frame 12, and a headrest 22 attached to the frame 12. I have. Further, the seat 200 includes a cushion skin 18 as an example of the skin covering the seat cushion 14, and a back skin 20 as an example of the skin covering the seat back 16.

The frame 12 includes a cushion frame 30 that supports the seat cushion 14, a back frame 32 that supports the seat back 16, and a pair of head brackets 34 that support the headrest 22.

Further, the rear end side of the cushion frame 30 in the front-rear direction of the seat and the lower end side of the back frame 32 in the vertical direction are connected via a shaft member 36 extending in the width direction of the seat. The back frame 32 swings around the shaft member 36 as the center of rotation.

Two head brackets 34 are attached to the upper end side of the back frame 32 and are provided at intervals in the seat width direction. The head bracket 34 has a cylindrical shape extending in the vertical direction, and a pair of support rods 22A provided on the headrest 22 is inserted. As a result, the headrest 22 is supported by the frame 12 (head bracket 34).

The seat cushion 14 is made of a seat cushion material formed of foam. The seat cushion material according to the present embodiment is applied to the seat cushion 14. The first region of the foam of the seat cushion material according to the present embodiment is arranged so as to be on the seated occupant side. Further, the seat cushion 14 includes a pair of side support portions 40 that prevent the seated occupant from slipping in the seat width direction. The side support portions 40 are formed at both ends of the seat cushion 14 in the seat width direction, extend in the front-rear direction of the seat, and project upward as compared with other portions.

Further, the seat cushion 14 has a main portion 42 arranged between the pair of side support portions 40, a main front portion 44 arranged in front of the main portion 42 in the front-rear direction of the seat, and a main portion 42. It is provided with a main rear portion 46 arranged behind the seat in the front-rear direction. The main portion 42 supports the buttocks of the seated occupant, and the main front portion 44 supports the thighs of the seated occupant.

A groove portion 48 extending in the front-rear direction of the seat is formed between the main front portion 44, the main portion 42, the main rear portion 46, and the pair of side support portions 40, and the cushion skin 18 is fixed inside the groove portion 48. Wires (not shown) used in the above are arranged.

Further, a groove portion 50 extending in the seat width direction is formed between the main front portion 44 and the main portion 42, and between the main portion 42 and the main rear portion 46. Inside the groove 50, a wire (not shown) used for fixing the cushion skin 18 is arranged.

The seat back 16 is made of a seat cushion material formed of foam. The seat back 16 is arranged so that the seat cushion material according to the present embodiment is applied and the first region is on the occupant side. The seat back 16 includes a pair of side support portions 56 that prevent the upper body of the seated occupant from slipping in the seat width direction. The side support portions 56 are formed at both ends of the seat back 16 in the seat width direction, extend vertically, and project forward as compared to other portions.

Further, the seat back 16 is arranged below the main portion 58 arranged between the pair of side support portions 56, the main upper portion 60 arranged above the main portion 58, and the main portion 58. It has a main lower part 62 and. Then, the main portion 58 supports the waist portion of the seated occupant. Further, the main upper portion 60 supports the back of the seated occupant.

A groove 64 extending vertically is formed between the main upper portion 60, the main portion 58 and the main lower portion 62, and the pair of side support portions 56. Inside the groove 64, a wire (not shown) used for fixing the back skin 20 is arranged.

Further, a groove portion 66 extending in the seat width direction is formed between the main upper portion 60 and the main portion 58, and between the main portion 58 and the main lower portion 62. Inside the groove 66, a wire (not shown) used for fixing the back skin 20 is arranged.

As shown in FIG. 5, the cushion skin 18 includes a pair of side skin members 70, a front skin member 72, a main skin member 74, and a rear skin member 76. The side skin member 70 is a pair of skin members that cover the side support portion 40. The front skin member 72 is a skin member that covers the main front portion 44. The main skin member 74 is a skin member that covers the main portion 42. The rear skin member 76 is a skin member that covers the main rear portion 46.

Further, as shown in FIG. 5, the back skin 20 includes a pair of side skin members 80, an upper skin member 82, a main skin member 84, and a lower skin member 86. The pair of side skin members 80 that cover the side support portion 56 is a pair of skin members that cover the side support portion 56. The upper skin member 82 is a skin member that covers the main upper part 60. The main skin member 84 is a skin member that covers the main portion 58. The lower skin member 86 is a skin member that covers the main lower part 62. The skin member used for the cushion skin 18 and the back skin 20 is not particularly limited, and a material suitable for the purpose may be used.

Regarding the cushion skin 18 and the back skin 20, the respective skin members are connected by being sewn or the like with the surfaces of the cushion skin 18 and the back skin 20 being aligned with each other on the end side.

Although the seats according to the present embodiment have been described above with reference to FIGS. 4 and 5, the seats according to the present embodiment are not only the seats used in the front row of the vehicle but also the second row or the third row of the vehicle. It may be applied to the sheet used in the column.

Although the seat cushion material and the seat according to the present embodiment have been described in detail above, the seat cushion material and the seat according to the present embodiment are not limited thereto. It is clear that a person skilled in the art can come up with various modifications or amendments within the scope of the ideas described in the claims, and of course, the technical scope of the present embodiment is also related to them. It is understood that it belongs to.

Examples will be described below, but the cushioning material for seats according to the present embodiment is not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are all based on mass.

<Examples 1 to 26, Comparative Examples 1 to 9>
The materials shown in Tables 1 to 4 are blended at the ratios shown in Tables 1 to 4 so that the molar ratio (NCO INDEX) of (NCO group / active hydrogen group) becomes the value shown in Tables 1 to 4. The composition was prepared. Then, the composition was injected into a mold, and molding was performed at the mold temperatures shown in Tables 1 to 4 to obtain a foam having a thickness of 100 mm. In addition, in the preparation process of each raw material, it was carried out in a nitrogen purge atmosphere.

The materials shown in Tables 1 to 4 are as shown below.
-PPG (A0): A polyether polyol having three active hydrogen groups (OH groups) in one molecule (that is, having 3 functional groups) and having a weight average molecular weight of 6000.
PPG (A0 / A1 (9)): PPG (A0) and PPG (A1) (having 4 to 5 active hydrogens (OH groups) in one molecule (that is, the number of functional groups is 4 to 5), A polyether polyol having a weight average molecular weight of 12000) and 90/10 (PPG (A0) / PPG (A1): mass ratio) are mixed.
-PPG (A0 / A1 (19)): A polyether polyol in which PPG (A0) and PPG (A1) are mixed at 95/5 (PPG (A0) / PPG (A1): mass ratio).
-PPG (A0 / A1 (99)): A polyether polyol in which PPG (A0) and PPG (A1) are mixed at 99/1 (PPG (A0) / PPG (A1): mass ratio).
-PPG (A0 / A1 (8)): A polyether polyol in which PPG (A0) and PPG (A1) are mixed at 89/11 (PPG (A0) / PPG (A1): mass ratio).

-Catalyst (a): Triethylenediamine.
-Catalyst (b): Bis (dimethylaminoethyl) ether.

MDI (B): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 80/20 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (B-A0 / A1 (9)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (9)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 80/20 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (B-A0 / A1 (19)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (19)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 80/20 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (B-A0 / A1 (99)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (99)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 80/20 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (B-A0 / A1 (8)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (8)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 80/20 (monomeric MDI / polypeptide MDI: mass ratio).

MDI (C): An MDI-based polyisocyanate in which a monomeric MDI and a polymeric MDI are previously blended at a mixing ratio of 60/40 (monomeric MDI / polymeric MDI: mass ratio).
-TDI (D): Toluene diisocyanate (TDI)
MDI (E): A modified MDI-based isocyanate obtained by reacting monomeric MDI alone with a part of PPG (A0).

MDI (F): A modified MDI-based isocyanate obtained by previously reacting a monomec MDI and a polypeptide MDI with a part of PPG (A0). The mixing ratio of monomeric MDI and polypeptide MDI is 40/60 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (F-A0 / A1 (9)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (9)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 40/60 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (F-A0 / A1 (19)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (19)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 40/60 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (F-A0 / A1 (99)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (99)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 40/60 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (F-A0 / A1 (8)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (8)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 40/60 (monomeric MDI / polypeptide MDI: mass ratio).

MDI (G): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 35/65 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (G-A0 / A1 (9)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (9)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 35/65 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (G-A0 / A1 (19)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (19)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 35/65 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (G-A0 / A1 (99)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (99)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 35/65 (monomeric MDI / polypeptide MDI: mass ratio).
MDI (G-A0 / A1 (8)): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polypeptide MDI with a part of PPG (A0 / A1 (8)) in advance. The mixing ratio of monomeric MDI and polypeptide MDI is 35/65 (monomeric MDI / polypeptide MDI: mass ratio).

In addition, "-" in Tables 1 to 4 indicates that the corresponding component is not contained.

(evaluation)
For the foam obtained in each example, the density, Asker F hardness, air permeability, pulse NMR measurement, moist heat compression permanent strain, 25% hardness (ILD), hysteresis loss and logarithmic decrement were measured by the methods described above. went.
In addition, the vibration absorption comprehensive evaluation of the foams obtained in each example was performed. The vibration absorption comprehensive evaluation was performed based on the value of the logarithmic decrement. The evaluation criteria for the comprehensive evaluation of vibration absorption are as follows.
It should be noted that a foam having a vibration absorption comprehensive evaluation closer to A (◎) (that is, a foam having a higher logarithmic decrement rate) is more likely to travel on uneven road surfaces when used as a cushioning material for seats. The ride will be excellent.
<Comprehensive evaluation criteria for vibration absorption>
A (◎): Logarithmic decrement is 6.0 or more.
B (○): Logarithmic decrement is 3.0 or more and less than 6.0.
C (Δ): Logarithmic decrement is 1.5 or more and less than 3.0.
D (x): Logarithmic decrement is 1.0 or more and less than 1.5.
E (XX): Logarithmic decrement is 0.0 or more and less than 1.0.

The measurement sample used for measuring the air permeability and the logarithmic decrement was cut out according to the following procedure.
-Procedure for cutting out a sample for air permeability measurement-
-Sample for measuring air permeability in the first region: In the production of foam, the thickness is 5 mm from the surface layer of the surface that was in contact with the bottom surface of the mold toward the second region, and the thickness is 150 mm (length) x 150 mm (width). The measurement sample was cut out so as to be.
-Sample for measuring air permeability in the second region: The foam was cut at the center in the thickness direction and at a plane perpendicular to the thickness direction. A foam containing the second region was selected, and a measurement sample was cut out so as to have a thickness of 5 mm from the surface layer of the cut surface toward the second region and a length of 150 mm × a width of 150 mm.

-Procedure for cutting out a sample for logarithmic decrement measurement-
-Sample for logarithmic decrement measurement in the first region: In the production of foam, the thickness is 40 mm from the surface layer of the surface in contact with the bottom surface of the mold toward the second region, and the thickness is 10 mm (length) x (width). A measurement sample was cut out so as to have a size of 100 mm.
-Sample for logarithmic decrement measurement in the second region: The foam was cut at the center in the thickness direction and on a plane perpendicular to the thickness direction. A foam containing the second region was selected, and a measurement sample was cut out so as to have a thickness of 40 mm from the surface layer of the cut surface toward the second region and a length of 100 mm × a width of 100 mm.

From the above results, it can be seen that the seat cushion material of the present embodiment is excellent in riding comfort when traveling on an uneven road surface.

100 seat cushioning material, 102 first area, 104 second area, 200 seats, 202 seats, 204 backrest

Claims (8)

A foam of a composition containing a polyol and a diphenylmethane diisocyanate-based isocyanate.
It has a hard segment and a soft segment, and
In the first region, where the Asker F hardness is 20 or more and less than 50, and the air permeability is 1 to 35 mL / cm ² / sec.
For seats made of foam having an Asker F hardness of 50 or more and 70 or less, an air permeability of 1 to 35 mL / cm ² / sec, and a second region adjacent to the first region. Cushion material. The spin-spin relaxation time (T2) of the hard segment in the H1 solid-state pulse NMR measurement in the ^first region is 30 μsec or more and 40 μsec or less, and the volume existence ratio of the hard segment is 10% or more and 40% or less.
The spin-spin relaxation time (T2) of the hard segment in the H1 solid ^- state pulse NMR measurement in the second region is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less. The cushion material for a seat according to claim 1. The seat according to claim 1 or 2, wherein the isocyanate index (NCO INDEX) represented by the molar ratio (NCO group / active hydrogen group) of the isocyanate group to the active hydrogen group of the composition is 80 to 95. Cushion material. The polyol is
Polycarbonate A0 having a weight average molecular weight of 200 to 10000 and a functional group number of 3
Containing polyol A1 having a weight average molecular weight of 1000 to 14000 and a functional group number of 4 to 5.
The seat cushion material according to any one of claims 1 to 3, wherein the mass ratio of the polyol A0 to the polyol A1 (polypoly A0 / polyol A1) is 90/10 to 99/1. 17. Seat cushioning material. The seat cushion material according to any one of claims 1 to 5, wherein the seat cushion material is for a vehicle. The seat cushion material according to any one of claims 1 to 6, wherein the seat cushion material is for a vehicle. A seat that supports the buttocks of the seated occupant,
The backrest that supports the back and waist of the seated occupant,
Equipped with
A seat having the seat cushioning material according to any one of claims 1 to 7, wherein at least one of the seat portion and the backrest portion is provided.

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