JP2015024028A - Seat cushion for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat cushion for a vehicle which gives a soft feeling upon seating but does not give a bottom-touch feeling, and has reduced seating average pressure.SOLUTION: A seat cushion for a vehicle is obtained by lamination of a first polyurethane foam and a second polyurethane foam. The first polyurethane foam has density of 20-80 kg/m, 25% hardness of 30-140 N/314 cm, and impact resilience of 4-30%, and the second polyurethane foam has density of 20-80 kg/m, 25% hardness of 200-350 N/314 cm, and impact resilience of 40-85%.

Description

  The present invention relates to a vehicle seat cushion in which a flexible polyurethane foam is laminated, and a method for manufacturing a vehicle seat cushion.

Conventionally, a flexible polyurethane foam has been used for a vehicle seat cushion, and a solution to the problem of ride comfort has been proposed. In particular, it is required to have a contradictory performance that there is no feeling of bottoming while having a soft feeling at the time of sitting and a small pressure deviation at the time of sitting.
Patent Document 1 proposes an automobile seat having a soft surface and no bottoming for comfortable ride of the automobile seat. The polyurethane sheet has a hardness of 150 to 190 N and a hardness of 230 to 280 N. A method has been proposed in which a flexible polyurethane foam is laminated with the lower hardness as the upper layer. Patent Document 2 proposes a method in which a laminated body of flexible polyurethane foams having different hardnesses is hot-pressed with the side surfaces in an open state and the upper and lower surfaces within a compression ratio of 25 to 60%.

Patent No. 4926599 Japanese Patent No. 4393453

However, the polyurethane foams described in Patent Document 1 and Patent Document 2 are obtained by laminating two layers of foams having different hardnesses. Patent Document 1 proposes that the soft feeling on the surface of the upper seat cushion is good and reduces the feeling of bottoming, but the hardness of the upper foam is 150 to 190 N, and the soft feeling is not sufficient. It is unclear whether the average seating pressure could be reduced.
Patent Document 2 improves the feeling of bottoming at the time of sitting by heating and compressing a foam having a hardness of 50 to 130 N with a hot press, but the surface condition changes due to heating, and the soft feeling Seems to be lacking. Moreover, it is unclear whether the pressure at the time of sitting could be reduced.
The present invention has been made in view of the above problems, and relates to a method for producing a seat cushion for a vehicle, particularly a flexible polyurethane foam for an automobile seat.

The present invention relates to a vehicle seat cushion obtained by laminating a first polyurethane foam and a second polyurethane foam, and the first polyurethane foam has a density of 20 to 80 kg / m ³ and a 25% hardness of 30. 140 N / 314 cm ² , rebound resilience 4-30%, the second polyurethane foam has a density 20-80 kg / m ³ , 25% hardness 200-350 N / 314 cm ² rebound resilience 40 The vehicle seat cushion is 85%, and the thickness ratio of the first polyurethane foam to the total thickness of the first polyurethane foam and the second polyurethane foam is 10 to 70%.

  According to the present invention, it is possible to obtain a vehicle seat cushion having a good soft feeling on the surface, a feeling of bottoming at the time of sitting, and a low seating average pressure. Further, a vehicle seat cushion having a small hardness change (temperature sensitivity) with respect to a temperature change can be obtained.

It is an example which showed typically the seat cushion for vehicles of the present invention, and laminates the 1st polyurethane foam and the 2nd polyurethane foam.

The present invention is a vehicle seat cushion (hereinafter also simply referred to as a seat cushion) obtained by laminating a first polyurethane foam and a second polyurethane foam, which will be described later.
A vehicle seat cushion is used for a seat portion of a vehicle seat such as an automobile, and is made of a flexible polyurethane foam. A flexible polyurethane foam is a synthetic resin having an open-cell structure and has flexibility and resilience.
The vehicle seat cushion according to the present invention has a low hardness, a good soft feeling, a small bottom feeling, and a low seating average pressure.

In the present specification, unless otherwise specified, the density, the hardness at 65% load, and the hardness at 25% load are values when a flexible polyurethane foam having a thickness of 100 mm is measured, respectively.
The soft feeling is evaluated by a static spring constant at a load of 98 N obtained from a load test based on the performance test method for the pad material of the automobile seat of JASO Automotive Standard B408-89. When the static spring constant at a load of 98 N is small, the soft feeling is good. More specifically, the static spring constant of the seat cushion is preferably 20 N / mm or less, more preferably 10 N / mm or less, and further 7 N / mm or less. preferable.

  The feeling of bottoming is evaluated by Sag-Factor expressed as hardness at 65% load (ILD) / hardness at 25% load (ILD). The hardness at 65% load (ILD) and the hardness at 25% load (ILD) are values measured by a measuring method based on JIS K6400 (1997 edition). When the Sag-Factor of the vehicle seat cushion is 3.3 or more, the feeling of bottoming is small, and a comfortable ride is obtained. 4.3 to 15 is more preferable, and 5 to 15 is even more preferable. The seating average pressure can be measured by the following method. A subject sits on a polyurethane foam having a length of 400 mm and a thickness of 100 mm in the center of the foam, and an average pressure value after 1 minute is measured using a pressure sensor (Xsensor model: X2GSM (registered trademark) -8). .

A higher value indicates a greater burden on the human body at the time of sitting, and a lower value indicates that the burden on the human body at the time of sitting is reduced. As for the seating average pressure, even if the same load is applied to the seat cushion, if the area to which the load is applied is large, the seating average pressure becomes small.
Increasing the area to which the load is applied can be achieved by reducing the hardness of the first polyurethane foam, but if the foam hardness is too low, a feeling of bottoming occurs. The seat cushion of the present invention is characterized in that it has a low hardness and a soft feeling but no bottom feeling.

(First polyurethane foam)
The first polyurethane foam is a flexible polyurethane foam having a density of 20 to 80 kg / m ³ , a 25% hardness (ILD hardness) of 30 to 140 N / 314 cm ² and a rebound resilience of 5 to 30%. Density, 25% hardness (ILD), and impact resilience are values measured by a measuring method based on JIS K6400 (1997 edition). Specifically, it is a value obtained by measuring after measuring the flexible polyurethane foam to be measured for 24 hours or longer in a room controlled at 23 ° C. and 50% relative humidity.
The first polyurethane foam constitutes the upper layer of the vehicle seat cushion and is directly touched by the occupant's body when seated.
When the density, 25% hardness, and impact resilience are within the above ranges, in the foam laminated with the second polyurethane foam, there is no feeling of bottoming because subduction is suppressed while obtaining a soft feel. It becomes a form. Further, since the sitting average pressure is low and the body pressure dispersibility is good, the feeling of fatigue at the time of sitting can be reduced.
The density of the first polyurethane foam is 20 to 80 kg / m ³ , and preferably ³⁰ to 70 kg / m ³ . The density can be controlled by adjusting the type and amount of the foaming agent.

The value of 25% hardness (ILD) is a value obtained by measuring the foam cured as described above.
25% hardness is ^{30~140N / 314cm 2, 50~120N / 314cm} 2 are preferred. The 25% hardness can be controlled by adjusting the number of functional groups of the polyol and the isocyanate index. The isocyanate index is a numerical value represented by 100 times the number of isocyanate groups with respect to the number of active hydrogens such as polyol and water, and hereinafter simply referred to as an isocyanate index.
The rebound resilience is 5 to 30%, preferably 5 to 20%.
The rebound resilience can be controlled by adjusting the isocyanate index.

  The thickness ratio of the first polyurethane foam in the total thickness of the first polyurethane foam and the second polyurethane foam is 10 to 70%. When the thickness ratio is 10% or more, the soft feeling on the surface of the vehicle seat cushion becomes good, and the stress deviation at the time of sitting can be reduced. When the thickness ratio is 70% or less, the feeling of bottoming at the time of sitting can be reduced. By adjusting the thickness ratio within the above range, the Sag-factor of the laminated polyurethane foam can be adjusted. The thickness ratio is preferably 20 to 70%, more preferably 30 to 70%. The specific thickness of the first polyurethane foam is preferably 30 to 105 mm, more preferably 45 to 105 mm, when the total thickness of the first polyurethane foam and the second polyurethane foam is 150 mm.

Moreover, it is preferable that the hardness change rate of 5 degreeC Asker rubber hardness (F) with respect to 20 degreeC of a 1st polyurethane foam is 100% or less, and it is more preferable that it is 80% or less.
The hardness change rate is obtained from the following equation by measuring the hardness of the polyurethane foam with an Asker rubber hardness meter F type.
Hardness change rate (%) = ((hardness measured at 5 ° C.−hardness measured at 20 ° C.) × 100) / hardness measured at 20 ° C.
When the rate of change in hardness is in the above range, it is a foam with low temperature sensitivity, and it can be said that changes in physical properties due to body temperature and seasonal fluctuations are small. Further, the first polyurethane foam preferably has an Asker rubber hardness (F) of 20 ° C. or less.

(First polyurethane foam production method)
The polyurethane foam can be produced by a known method.
The foam raw material is obtained by reacting in the presence of polyols, polyisocyanates, foam stabilizers, urethanization catalysts and blowing agents.
As the polyols, polyether polyol, polymer polyol, polyester polyol and the like can be used. Furthermore, the polyols are preferably polyols including the following polyol (A) and the following polyol (B).

(Polyol A)
Polyol (A) was obtained by ring-opening addition polymerization of alkylene oxide in the presence of a polymerization catalyst in the initiator, having an average hydroxyl number of 2 to 3, a hydroxyl value of 5 to 90 mgKOH / g, and a total unsaturation degree. Is a polyether polyol (polyoxyalkylene polyol) having an oxyethylene group content of 60% by mass or less in all oxyalkylene groups (100% by mass).

Examples of the polymerization catalyst include an alkali metal catalyst, a cesium catalyst, a phosphate catalyst, a composite metal cyanide complex catalyst (DMC catalyst), and the like. In terms of easily obtaining a polyol having a total unsaturation degree of 0.1 meq / g, It is preferable to use a DMC catalyst.
As the double metal cyanide complex catalyst, for example, those described in JP-B-46-27250 can be used. Specific examples include a complex mainly composed of zinc hexacyanocobaltate, and an ether and / or alcohol complex thereof is preferable. Examples of ethers include ethylene glycol dimethyl ether (glyme), diethylene glycol dimethyl ether (diglyme), ethylene glycol mono-tert-butyl ether (METB), ethylene glycol mono-tert-pentyl ether (METP), diethylene glycol mono-tert-butyl ether (DETB), Tripropylene glycol monomethyl ether (TPME) and the like are preferable. As the alcohol, tert-butyl alcohol or the like is preferable.

  As the initiator, a compound having 2 or 3 active hydrogen atoms in the molecule is used alone or in combination. Specific examples of the compound having 2 active hydrogens include ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, and dipropylene glycol. Specific examples of the compound having 3 active hydrogens include glycerin and trimethylolpropane. Further, it is preferable to use a polyether polyol obtained by subjecting these compounds to ring-opening addition polymerization of alkylene oxide, preferably propylene oxide.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-epoxybutane, and 2,3-epoxybutane. Of these, propylene oxide or a combination of propylene oxide and ethylene oxide is preferred.
When propylene oxide and ethylene oxide are used in combination, each may be separately subjected to ring-opening addition polymerization to form a block polymer chain, or a mixture of propylene oxide and ethylene oxide may be subjected to ring-opening addition polymerization to form a random polymer chain. May be. Furthermore, the formation of random polymer chains and the formation of block polymer chains may be combined. When forming a block polymer chain, the order of ring-opening addition polymerization of alkylene oxide is preferably added in the order of propylene oxide and ethylene oxide, or ethylene oxide is added first, and propylene oxide and ethylene oxide are added in this order. By ring-opening addition polymerization in this order, it becomes easy to have ethylene oxide at the terminal, many of the hydroxyl groups of the polyoxyalkylene polyol (A) become primary hydroxyl groups, and the reactivity between the polyol (A) and the polyisocyanate compound is high. Become. As a result, the moldability of the resulting flexible polyurethane foam tends to be favorable, which is preferable. The terminal is preferably ethylene oxide.

The oxyethylene group content in 100% by mass of the polyoxyalkylene polyol (A) is preferably 60% by mass or less, and particularly preferably 30% by mass or less. By making the oxyethylene group content 60% by mass or less, the moldability of the flexible polyurethane foam is likely to be good, and the average number of hydroxyl groups of the polyol (A) is preferably 2 to 3. The average number of hydroxyl groups in the present invention means the average value of the number of active hydrogens in the initiator. By setting the average number of hydroxyl groups to 2 to 3, it is possible to avoid a problem that physical properties such as dry heat compression set of the obtained flexible polyurethane foam are remarkably lowered. In addition, it is possible to avoid problems such as a decrease in elongation of the resulting flexible polyurethane foam, an increase in hardness and a decrease in physical properties such as tensile strength. As the polyol (A), it is preferable to use a polyether diol having 2 hydroxyl groups in an amount of 50 to 100% by mass in the polyol (A) from the viewpoint of easily suppressing the temperature sensitivity.
The hydroxyl value of the polyol (A) is preferably 5 to 90 mgKOH / g. By setting the hydroxyl value to 5 mgKOH / g or more, it is possible to stably produce a flexible polyurethane foam while suppressing collaps etc. Moreover, by making a hydroxyl value into 90 mgKOH / g or less, the softness | flexibility of the flexible polyurethane foam manufactured is not impaired, and a resilience elastic modulus is restrained low. The hydroxyl value of the polyol (A) is more preferably from 10 to 60 mgKOH / g, most preferably from 15 to 60 mgKOH / g.

(Polyol (B))
The polyol (B) is preferably a polyether polyol having an average number of hydroxyl groups of 2 to 4, a hydroxyl value of 15 to 250 mgKOH / g, and excluding the polyol (A). It is preferable that the polyether polyol produced using the double metal cyanide complex catalyst as the alkylene oxide ring-opening addition polymerization catalyst is not included in the polyol (B).

  As a polymerization catalyst used for manufacture of a polyol (B), a phosphazene compound, a Lewis' acid compound, or an alkali metal compound catalyst is preferable, and an alkali metal compound catalyst is especially preferable among these. Examples of the alkali metal compound catalyst include potassium hydroxide (KOH) and cesium hydroxide (CsOH).

  Examples of the alkylene oxide used for the production of the polyol (B) include ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane and the like. Of these, propylene oxide or a combination of propylene oxide and ethylene oxide is preferred.

  As an initiator used for producing the polyol (B), a compound having 2 or 3 active hydrogen atoms in the molecule is used alone or in combination. Specific examples of the compound having 2 or 3 active hydrogens include polyhydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, glycerin and trimethylolpropane; bisphenol A and the like And polyamines such as monoethanolamine, diethanolamine, triethanolamine, and piperazine. Of these, polyhydric alcohols are particularly preferred. Further, it is preferable to use a high hydroxyl group polyether polyol obtained by ring-opening addition polymerization of alkylene oxide, preferably propylene oxide, to these compounds.

  The polyol (B) in the present invention may be a polymer-dispersed polyol. The polyol (B) being a polymer-dispersed polyol means a dispersion system in which polymer fine particles (dispersoid) are stably dispersed using the polyol (B) as a base polyol (dispersion medium). Examples of the polymer of the polymer fine particles include addition polymerization polymers and condensation polymerization polymers. The addition polymerization polymer can be obtained by homopolymerizing or copolymerizing monomers such as acrylonitrile, styrene, methacrylic acid ester, acrylic acid ester and the like. Examples of the polycondensation polymer include polyester, polyurea, polyurethane, and polymethylol melamine. In the polymer-dispersed polyol, polymer fine particles can be stably present by polymerizing the monomer with a base polyol as a dispersion medium. A dispersion stabilizer may be used to further stabilize the polymer fine particles. The presence of polymer fine particles in the polyol is effective in improving mechanical properties such as the hydroxyl value of the polyol being kept low and the hardness of the flexible polyurethane foam being increased. Moreover, the content ratio of the polymer fine particles in the polymer-dispersed polyol is not particularly limited, but is preferably 0 to 5% by mass with respect to the entire polyol (B). The various properties (unsaturation, hydroxyl value, etc.) of the polymer-dispersed polyol as a polyol are considered for the base polyol excluding the polymer fine particles.

  In the present invention, the hydroxyl value of the polyol (B) is preferably 15 to 250 mgKOH / g. By setting the hydroxyl value to 15 mgKOH / g or more, it is possible to stably produce a flexible polyurethane foam while suppressing collaps etc. Moreover, by making a hydroxyl value into 250 mgKOH / g or less, the softness | flexibility of the flexible polyurethane foam manufactured is not impaired, and a resilience elastic modulus is restrained low.

  For the production of the first polyurethane foam of the present invention, monool (C) may be used in addition to polyol (A) and polyol (B). The monool (C) in the present invention is a polyether monool having a hydroxyl value of 10 to 200 mgKOH / g. That is, it is a polyether monool obtained by ring-opening addition polymerization of alkylene oxide using an alkylene oxide ring-opening addition polymerization catalyst to an initiator having one active hydrogen in one molecule.

  As the alkylene oxide ring-opening addition polymerization catalyst used for the production of monool (C), a composite metal cyanide complex catalyst, a phosphazene compound, a Lewis acid compound or an alkali metal compound catalyst is preferable, and among these, a composite metal cyanide complex catalyst is particularly preferable. preferable. That is, the monool (C) is preferably a polyether monool having a polyoxyalkylene chain obtained by ring-opening addition polymerization of alkylene oxide using a double metal cyanide complex catalyst.

  Examples of the alkylene oxide used in the production of the monool (C) include the same as the polyols (A) to (B). Preferably, propylene oxide or a combination of propylene oxide and ethylene oxide is used, and only propylene oxide is particularly preferable. It is preferable to use only propylene oxide because durability during humidification is improved.

  As an initiator used for production of monool (C), a compound having only one active hydrogen atom in the molecule is used. Specific examples thereof include monools such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and tert-butyl alcohol; monohydric phenols such as phenol and nonylphenol; 2 such as dimethylamine and diethylamine. Secondary amines and the like. Monools are particularly preferred.

The hydroxyl value of the monool (C) is preferably 10 to 200 mgKOH / g, more preferably 10 to 120 mgKOH / g.
In the present invention, the ratio of the polyol (A) and the polyol (B) is the ratio of the polyol (A) in the total (100% by mass) of the polyol (A) and the polyol (B), It is preferable that it is 50 mass%, and it is more preferable that it is 10-30 mass%. By setting the ratio of the polyol (A) in the polyol mixture within the above range, a flexible polyurethane foam having low rebound and small change in resilience modulus and hardness with respect to temperature change (low temperature sensitivity) can be obtained.

  The total proportion of the polyol (A) and the polyol (B) in the polyol mixture (100% by mass) is preferably 75% by mass or more, more preferably 80% by mass or more, and particularly preferably 85% by mass or more. 90% by mass or more is particularly preferable. By setting the total ratio of the polyol (A) and the polyol (B) in the polyol mixture within the above range, a flexible polyurethane foam having an appropriate hardness can be obtained.

  In the polyol mixture of the present invention, other polyols (D) not classified as any of polyol (A), polyol (B), and monool (C) may be used. The proportion of the other polyol (D) is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 0% by mass in the polyol mixture (100% by mass).

  In the present invention, specific examples of a particularly suitable composition of the polyol mixture (100% by mass) include 10 to 60% by mass of polyol (A), 40 to 80% by mass of polyol (B), and monool (C ) Containing 2 to 24% by mass.

<Polyisocyanate compound>
The polyisocyanate compound used in the present invention is not particularly limited, and is a polyisocyanate having two or more isocyanate groups, such as aromatic, alicyclic, and aliphatic groups; a mixture of two or more of the above polyisocyanates; And modified polyisocyanates obtained by modifying.

  Specific examples of the polyisocyanate include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate (common name: crude MDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate. (HMDI) and the like. Specific examples of the modified polyisocyanate include prepolymer-modified products, nurate-modified products, urea-modified products, and carbodiimide-modified products of the above polyisocyanates. Among these, TDI, MDI, crude MDI, or modified products thereof are preferable. Further, among these, use of TDI, crude MDI, or a modified product thereof (especially a prepolymer modified product) is preferable in terms of improving foaming stability and improving durability. In particular, it is preferable to use a polyisocyanate compound having a relatively low reactivity among TDI, crude MDI, or a modified product thereof because air permeability is improved. Specifically, a TDI mixture having a high ratio of 2,6-TDI (30% by mass or more is particularly preferable) is preferable.

  The polyisocyanate compound is used in such an amount that the ratio of the total active hydrogen-containing compound to the polyisocyanate compound in the raw material is 80 to 120 in terms of isocyanate index. A raw material means a polyol mixture, a polyisocyanate compound, a urethanization catalyst, a foaming agent, and a foaming agent. The active hydrogen-containing compound refers to a polyol mixture, water that can be used as a foaming agent, and the like. The isocyanate index is represented by 100 times the numerical value obtained by dividing the equivalent of the isocyanate group of the polyisocyanate compound by the total equivalent of all active hydrogens in all active hydrogen-containing compounds in the raw materials such as polyol and water.

<Urethane catalyst>
As the urethanization catalyst for reacting a polyol and a polyisocyanate compound, any catalyst that promotes the urethanization reaction can be used. For example, triethylenediamine, bis (2-dimethylaminoethyl) ether, N, N, N ′, Tertiary amines such as N′-tetramethylhexamethylenediamine; carboxylic acid metal salts such as potassium acetate and potassium 2-ethylhexanoate; organometallic compounds such as stannous octoate and dibutyltin dilaurate.

<Foam stabilizer>
Examples of the foam stabilizer include silicone foam stabilizers and fluorine foam stabilizers. Among these, a silicone type foam stabilizer is preferable. Of the silicone foam stabilizers, silicone foam stabilizers based on polyoxyalkylene / dimethylpolysiloxane copolymers are preferred. The commercially available foam stabilizer is a composition, and the foam stabilizer composition may be a polyoxyalkylene / dimethylpolysiloxane copolymer alone or may contain other combined components. Examples of other combined components that may be included include polyalkylmethylsiloxanes, glycols, and polyoxyalkylene compounds. As the foam stabilizer used in the present invention, a foam stabilizer composition containing a polyoxyalkylene / dimethylpolysiloxane copolymer, a polyalkylmethylsiloxane and a polyoxyalkylene compound is particularly preferred from the viewpoint of foam stability. An example of a commercially available foam stabilizer composition is SRX-298 (trade name) manufactured by Toray Dow Corning. Two or more types of these foam stabilizers may be used in combination, or a foam stabilizer other than the specific foam stabilizer may be used in combination.

  0.01-2 mass parts is preferable with respect to 100 mass parts of a polyol mixture, and, as for the usage-amount of a foam stabilizer, 0.1-1.5 mass parts is more preferable.

<Foaming agent>
There is no restriction | limiting in particular as a foaming agent, Well-known foaming agents, such as a fluorinated hydrocarbon, can be used. However, the foaming agent used in the present invention is preferably at least one selected from water and an inert gas. Specific examples of the inert gas include air, nitrogen, carbon dioxide gas, and the like. Of these, water is preferred. That is, in the present invention, it is particularly preferable to use only water as a foaming agent.

  When water is used, the amount of the blowing agent is preferably 10 parts by mass or less, more preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the polyol mixture.

  In the production of the flexible polyurethane foam of the present invention, a crosslinking agent may be used as long as the physical properties of the first polyurethane foam are not impaired. As a crosslinking agent, the thing similar to the crosslinking agent in the 2nd polyurethane foam mentioned later can be used. As for the usage-amount of a crosslinking agent, 0-5 mass parts is preferable with respect to 100 mass parts of a polyol.

<Other auxiliaries>
In producing the flexible polyurethane foam of the present invention, desired additives can be used in addition to the urethanization catalyst, foaming agent and foam stabilizer described above. Additives include fillers such as potassium carbonate and barium sulfate; surfactants such as emulsifiers; anti-aging agents such as antioxidants and ultraviolet absorbers; flame retardants, plasticizers, colorants, anti-fungal agents, and foam breaking Agents, dispersants, discoloration inhibitors and the like.

(Second polyurethane foam)
The second polyurethane foam is a polyurethane foam having a density of 20 to 80 kg / m ³ , a 25% hardness of 200 to 350 N / 314 cm ² and a rebound resilience of 40 to 85%.
The second polyurethane foam supports the plastic deformation of the first polyurethane foam as an upper layer, whereby the seating average pressure can be reduced.
The density of the second polyurethane foam is 20 to 80 kg / m ³ , and preferably ³⁰ to 70 kg / m ³ . When the density of the second polyurethane foam is within the above range, it is preferable in that the feeling of bottoming when laminated with the first polyurethane foam can be further reduced.

The 25% hardness of the second polyurethane foam is 200 to 350 N / 314 cm ² , and preferably 220 to 330 N / 314 cm ² . When the 25% hardness is within the above range, deformation of the first polyurethane foam can be supported, and the seating average pressure can be within a preferable range.
The rebound resilience is 40 to 85%, preferably 50 to 85%. When the rebound resilience is in the above range, the deformation of the first polyurethane foam can be supported, and the average seating pressure in the laminate with the first polyurethane foam can be in the preferred range.
The density, hardness, and impact resilience can be controlled in the same manner as for the first foam.

(Method for producing second polyurethane foam)
The second polyurethane foam is obtained by reacting a polyoxyalkylene polyol and a polyisocyanate compound in the presence of a urethanization catalyst, a foaming agent, and a foam stabilizer. As a polyoxyalkylene polyol, the thing similar to what was illustrated in the polyol (B) of the 1st polyurethane foam can be used.
As the polyisocyanate compound, the same compounds as those exemplified for the first polyurethane foam can be used. The amount of the polyisocyanate compound used is a value represented by 100 times the number of isocyanate groups relative to the number of active hydrogens such as polyol and water (usually this number is referred to as the isocyanate index), preferably 80 to 120, more preferably 85 to 85. 115, particularly preferably 90 to 110. When the amount of the polyisocyanate compound is in this range, it is preferable in that the deformation of the first polyurethane foam can be supported and the seating average pressure can be in a preferable range.
As a foaming agent, the thing similar to what was illustrated by the 1st polyurethane foam can be used. When only a water is used for a foaming agent, it is 0.1-10 mass with respect to 100 mass parts of a polyol. Part is preferred.

  In producing the second polyurethane foam, a crosslinking agent may be used.

  As the crosslinking agent, a compound having an average hydroxyl number of 2.0 to 8.0 and a hydroxyl value of 200 to 2,000 mgKOH / g is preferable. Examples of the crosslinking agent include compounds having two or more functional groups selected from a hydroxyl group, a primary amino group, and a secondary amino group. A crosslinking agent may be used individually by 1 type, and may use 2 or more types together.

  As the crosslinking agent having a hydroxyl group, a compound having 2 to 8 hydroxyl groups is preferable, a polyhydric alcohol, a low molecular weight polyoxyalkylene polyol obtained by adding an alkylene oxide to a polyhydric alcohol, and a polyol having a tertiary amino group. Etc.

  Specific examples of the crosslinking agent having a hydroxyl group include ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, monoethanolamine, diethanolamine, and triethanol. Amine, glycerin, sorbitol, sucrose, pentaerythritol, N-alkyldiethanol, bisphenol A-alkylene oxide adduct, glycerin-alkylene oxide adduct, trimethylolpropane-alkylene oxide adduct, pentaerythritol-alkylene oxide adduct Sorbitol-alkylene oxide adduct, sucrose-alkylene oxide adduct, aliphatic amine-alkylene oxide adduct, alicyclic amine Down - alkylene oxide adduct, a heterocyclic polyamine - alkylene oxide adducts, aromatic amines - alkylene oxide adducts, polyol derived from a natural product and the like.

  Heterocyclic polyamine-alkylene oxide adducts include piperazine, short-chain alkyl-substituted piperazine (2-methylpiperazine, 2-ethylpiperazine, 2-butylpiperazine, 2-hexylpiperazine, 2,5-, 2,6-, 2, 3- or 2,2-dimethylpiperazine, 2,3,5,6- or 2,2,5,5-tetramethylpiperazine, etc.), aminoalkyl-substituted piperazine (1- (2-aminoethyl) piperazine, etc.). ) And the like are obtained by ring-opening addition polymerization of alkylene oxide.

  Examples of the crosslinking agent (amine-based crosslinking agent) having a primary amino group or a secondary amino group include aromatic polyamines, aliphatic polyamines, and alicyclic polyamines.

  As the aromatic polyamine, an aromatic diamine is preferable. As the aromatic diamine, an aromatic diamine having one or more substituents selected from an alkyl group, a cycloalkyl group, an alkoxy group, an alkylthio group, and an electron-withdrawing group in an aromatic nucleus to which an amino group is bonded is preferable. Diaminobenzene derivatives are particularly preferred.

  The substituent other than the electron-withdrawing group is preferably bonded to 2 to 4 aromatic nuclei to which the amino group is bonded, and is bonded to one or more of the ortho positions with respect to the binding site of the amino group. It is more preferable that it is bonded to all.

  It is preferable that one or two electron-withdrawing groups are bonded to the aromatic nucleus to which the amino group is bonded. An electron-withdrawing group and another substituent may be bonded to one aromatic nucleus.

The number of carbon atoms of the alkyl group, alkoxy group, and alkylthio group is preferably 4 or less.
As the cycloalkyl group, a cyclohexyl group is preferable.

  As the electron withdrawing group, a halogen atom, a trihalomethyl group, a nitro group, a cyano group, and an alkoxycarbonyl group are preferable, and a chlorine atom, a trifluoromethyl group, and a nitro group are particularly preferable.

  Aliphatic polyamines include diaminoalkanes having 6 or less carbon atoms, polyalkylene polyamines, polyamines obtained by converting some or all of the hydroxyl groups of low molecular weight polyoxyalkylene polyols to amino groups, and two or more aminoalkyl groups. An aromatic compound etc. are mentioned.

  Examples of the alicyclic polyamine include cycloalkanes having two or more amino groups and / or aminoalkyl groups.

  Specific examples of the amine-based crosslinking agent include 3,5-diethyl-2,4 (or 2,6) -diaminotoluene (DETDA), 2-chloro-p-phenylenediamine (CPA), 3,5-dimethylthio- 2,4 (or 2,6) -diaminotoluene, 1-trifluoromethyl-3,5-diaminobenzene, 1-trifluoromethyl-4-chloro-3,5-diaminobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis (3,5-dimethyl-4-aminophenyl) methane, 4,4-diaminodiphenylmethane, ethylenediamine, m-xylenediamine, 1,4-diaminohexane, 1,3-bis (amino) Methyl) cyclohexane, isophoronediamine and the like, and diethyltoluenediamine [that is, 3,5-diethyl-2, (Or 2,6) - one or more mixture of diaminotoluene, dimethylthiotoluenediamine, monochlorodisilane aminobenzene, diaminobenzene derivative such as trifluoromethyl-diaminobenzene are preferred.

0.1-10 mass parts is preferable with respect to 100 mass parts of a polyol, and, as for the usage-amount of a crosslinking agent, 0.5-10 mass parts is preferable. If a crosslinking agent is used, 25% hardness and rebound resilience can be controlled.
Moreover, you may use additives, such as an emulsifier and antioxidant, as a raw material of a 2nd polyurethane foam as needed.

<Vehicle seat cushion>
The vehicle seat cushion of the present invention is obtained by laminating a first polyurethane foam and a second polyurethane foam.
Examples of the method for laminating the vehicle seat cushion of the present invention include the following methods (1) to (4).
(1) A method in which the first polyurethane foam and the second polyurethane foam are separately molded and then bonded together with an adhesive or the like.
(2) A method in which a composition for forming a first polyurethane foam and a composition for forming a second polyurethane foam are supplied to a molding die and integrally molded.
(3) After the second polyurethane foam is molded with a mold, it is sliced to a predetermined thickness and returned to the mold, and a composition for forming the first polyurethane foam is supplied. One-piece molding method.
(4) After molding the first polyurethane foam with a mold, it is sliced to a predetermined thickness and returned to the mold, and a composition for forming the second polyurethane foam is supplied. One-piece molding method.
Among these, the method of integrally molding with a molding die is preferable, and the methods (2) to (4) are preferable in that a bonding step with a complicated adhesive or the like is not required.

The thickness of the vehicle seat cushion of the present invention is the same as the total thickness of the first polyurethane foam and the second polyurethane foam, and is preferably 150 mm or less, more preferably 50 to 100 mm. Here, the thickness of the seat cushion for vehicles shall measure the center part of the seat surface of a seat cushion.
The vehicle seat cushion of the present invention preferably has a Sag-Factor of 4.3 or more, more preferably 5-15. When the Sag-Factor is 4.3 or more, the feeling of bottoming is small. It is preferable that the Sag-Factor is 15 or less because the sitting feeling is improved.

  The seating average pressure of the vehicle seat cushion of the present invention is preferably 70 mmHg (9331 Pa) or less, preferably 65 mmHg (8665 Pa) or less when a subject having a height of 165 cm and a weight of 65 kg sits on the center of the foam. More preferred. When the seating average pressure is 70 mmHg (9331 Pa) or less, it means that the pressure applied to the occupant at the time of sitting is small, and uncomfortable feeling and fatigue can be reduced.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by the following example. In addition, the numerical value in an Example and a comparative example shows a mass part. Further, the measurement of the degree of unsaturation was carried out by a method based on JIS K1557 (1970 edition).

(material)
Polyether polyol A1: Using potassium hydroxide catalyst, propylene oxide was subjected to ring-opening addition polymerization up to a molecular weight of 1000 using dipropylene glycol as an initiator, and then purified with magnesium silicate. Thereafter, the average number of hydroxyl groups obtained by ring-opening addition polymerization of propylene oxide using a complex metal cyanide complex catalyst using the compound as an initiator was 2, the hydroxyl value was 14 mgKOH / g, and the degree of unsaturation was 0.005 meq. / G polyoxypropylene polyol.

  Polyether polyol A2: Using potassium hydroxide catalyst, propylene oxide was subjected to ring-opening addition polymerization up to a molecular weight of 700 using dipropylene glycol as an initiator, and then purified with magnesium silicate. Thereafter, ring-opening addition polymerization of propylene oxide was performed using the compound as an initiator and a double metal cyanide complex catalyst. Subsequently, after ring-opening polymerization of ethylene oxide at the end using a potassium hydroxide catalyst, the catalyst was purified with magnesium silicate, the average number of hydroxyl groups was 2, the hydroxyl value was 28 mgKOH / g, and the degree of unsaturation was 0.02 meq / g, Polyoxypropylene ethylene polyol having a total oxyethylene group content of 24% by mass.

  Polyether polyol B1: Polyoxypropylene polyol having an average number of hydroxyl groups of 2 and a hydroxyl value of 160 mgKOH / g, obtained by ring-opening addition polymerization of propylene oxide using dipropylene glycol as an initiator using a potassium hydroxide catalyst.

  Polyether polyol B2: Polyoxypropylene polyol having an average number of hydroxyl groups of 3 and a hydroxyl value of 168 mgKOH / g, obtained by ring-opening addition polymerization of propylene oxide using glycerol as an initiator using a potassium hydroxide catalyst.

  Polyether polyol B3: The average number of hydroxyl groups obtained by ring-opening addition polymerization of a mixture of propylene oxide and ethylene oxide using glycerin as an initiator using a potassium hydroxide catalyst is 3, the hydroxyl value is 48 mgKOH / g, all oxyethylene groups are contained A polyoxypropylene oxyethylene polyol having an amount of 80% by mass.

  Polyether polyol B4: After the ring-opening addition polymerization of propylene oxide using glycerin as an initiator using a potassium hydroxide catalyst, the average number of hydroxyl groups obtained by ring-opening addition polymerization of ethylene oxide at the terminal is 3, and the hydroxyl value is 56 mg KOH / g, polyoxypropylene oxyethylene polyol having a total oxyethylene group content of 20% by mass.

  Polyether polyol B5: After ring-opening addition polymerization of propylene oxide using glycerin as an initiator using a potassium hydroxide catalyst, the average number of hydroxyl groups obtained by ring-opening addition polymerization of ethylene oxide at the terminal is 3, and the hydroxyl value is Polyoxypropylene oxyethylene polyol having 24 mg KOH / g and a total oxyethylene group content of 16% by mass.

  Polyether polyol B6: After the ring-opening addition polymerization of propylene oxide using glycerin as an initiator using a potassium hydroxide catalyst, the average number of hydroxyl groups obtained by ring-opening addition polymerization of ethylene oxide at the terminal is 3, and the hydroxyl value is A polyoxypropylene oxyethylene polyol having 34 mg KOH / g and a total oxyethylene group content of 14.5% by mass is obtained. A polymer-dispersed polyol having an amount of fine polymer obtained by copolymerizing acrylonitrile and styrene in the polyol of 35% by mass, an average number of hydroxyl groups of 3, and a hydroxyl value of 23.5 mgKOH / g.

  Polyether polyol B7: After the ring-opening addition polymerization of propylene oxide using pentaerythritol as an initiator using a potassium hydroxide catalyst, the average number of hydroxyl groups obtained by ring-opening addition polymerization of ethylene oxide at the terminal is 4, and the hydroxyl value Is 28 mg KOH / g, and the total oxyethylene group content is 13% by mass, polyoxypropylene oxyethylene polyol.

Polyether polyol B8: After the ring-opening addition polymerization of propylene oxide with glycerol as an initiator using a potassium hydroxide catalyst, the average number of hydroxyl groups obtained by ring-opening addition polymerization of ethylene oxide at the terminal is 3, and the hydroxyl value is A polyoxypropylene oxyethylene polyol having 28 mg KOH / g and a total oxyethylene group content of 17% by mass is obtained.
A polymer-dispersed polyol having an amount of fine particles obtained by copolymerizing acrylonitrile and styrene in the polyol of 22% by mass, an average number of hydroxyl groups of 3, and a hydroxyl value of 20 mgKOH / g.

  Polyether polyol B9: The average number of hydroxyl groups obtained by ring-opening addition polymerization of a mixture of propylene oxide and ethylene oxide using potassium hydroxide catalyst with dipropylene glycol as an initiator, the hydroxyl value is 56 mgKOH / g, all oxyethylenes A polyoxypropyleneoxyethylene polyol having a group content of 80% by mass.

Polyether monool C1: n-butyl alcohol as an initiator and having a mean hydroxyl number of 1 and a hydroxyl value of 16.7 mgKOH / g obtained by ring-opening addition polymerization of propylene oxide using a double metal cyanide complex catalyst Polyoxypropylene monool Crosslinker A: Glycerin Crosslinker B: Diethanolamine Foaming agent: Water.
Foam stabilizer A: Silicone foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., trade name: SRX-298)
Foam stabilizer B: Silicone foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., trade name: SZ-580)
Foam stabilizer C: Silicone foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., trade name: SZ-1327)
Foam stabilizer D: Silicone foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., trade name: SRX-274DL)
Urethane catalyst A: Dipropylene glycol solution of triethylenediamine. (Product name: TEDA-L33, manufactured by Tosoh Corporation)
Urethane catalyst B: Dipropylene glycol solution of bis-[(2-dimethylamino) ethyl] ether (trade name: TOYOCAT-ET, manufactured by Tosoh Corporation)
Urethane catalyst C: Tin 2-ethylhexanoate (Nitto Kasei Co., Ltd., trade name: Neostan U28)
Urethane catalyst D: Dioctyltin dilaurate (Nitto Kasei Co., Ltd., trade name: Neostan U810)
Polyisocyanate compound A: TDI-80 (mixture of 2,4-TDI / 2,6-TDI = 80/20% by mass), isocyanate group content 48.3% by mass (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate) T-80).

  Polyisocyanate compound B: 80/20 mass% mixture of TDI-80 and polymethylene polyphenyl polyisocyanate. Isocyanate group content 44.8% by mass (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate 1021).

[Composition Examples 1-9]
Among the raw materials and compounding agents shown in Table 1, the liquid temperature of the mixture of all raw materials other than the polyisocyanate compound (polyol system) is adjusted to 25 ° C. ± 1 ° C., and the polyisocyanate compound is adjusted to the liquid temperature 25 ± 1 ° C. did. A predetermined amount of polyisocyanate compound was added to the polyol system, mixed for 5 seconds with a mixer (3000 revolutions per minute), and immediately heated to 60 ° C. The upper mold having internal dimensions of 400 mm in length and width and 100 mm in height was released. The mold was poured into an aluminum mold, and the upper mold was quickly closed and foamed and molded in a sealed state. The compounding amount shown in parts by mass in Table 1 is an amount with respect to 100 parts by mass of the polyol mixture. After 6 minutes from the start of molding, the upper mold was opened to obtain a flexible polyurethane foam. The manufactured flexible polyurethane foam was allowed to stand for 24 hours or more in a room adjusted to room temperature (23 ° C.) and humidity 50%, and various physical properties were measured. The measurement results are shown in Table 2. Formulation Examples 1 to 6 are the first polyurethane foam formulation example 7 that is the upper layer, Comparative polyurethane foam that is the upper layer, and formulation examples 8 and 9 are the second polyurethane foam that is the lower layer.

[Examples 1 to 8 and Comparative Example 1]
After slicing the first polyurethane foam obtained in Formulation Examples 1 to 6 and the polyurethane foam of Comparative Example obtained in Formulation Example 7 to have a predetermined thickness, each was warmed to 60 ° C in length and width of 400 mm each. The upper mold having an inner dimension of 100 mm in height was placed in an aluminum mold in a released state. Of the raw materials and compounding agents of the second polyurethane foam shown in Table 1, the liquid temperature of the mixture of all raw materials other than the polyisocyanate compound (polyol system) is adjusted to 25 ° C. ± 1 ° C., The polyisocyanate compound was adjusted to a liquid temperature of 25 ± 1 ° C. A predetermined amount of a polyisocyanate compound was added to the polyol system, mixed for 5 seconds with a mixer (3000 rpm), poured into a mold, and the upper mold was quickly closed and integrally molded and foamed in a sealed state. After 6 minutes from the start of molding, the upper mold was opened to obtain a laminated flexible polyurethane foam. The manufactured flexible polyurethane foam was allowed to stand for 24 hours or more in a room adjusted to room temperature (23 ° C.) and humidity 50%, and various physical properties were measured. The results are shown in Table 3.

[Form physical property evaluation test]
About the obtained flexible polyurethane foam, density, 25% hardness (25% ILD hardness), 50% hardness (50% ILD hardness), 65% hardness (65% ILD hardness), rebound resilience, hysteresis loss, Was measured according to JIS K6400 (1997 edition).
Moreover, Sag-factor which is ratio of 65% hardness with respect to 25% hardness was calculated | required.

(Temperature sensitivity)
The temperature sensitivity was determined from the rate of change in surface hardness of the flexible polyurethane foam. The surface hardness was measured with an Asker rubber hardness meter F type (manufactured by Kobunshi Keiki Co., Ltd.). The center part of the flexible polyurethane foam was used for the measurement, a hardness meter F type was placed on the foam surface, and the hardness after 20 seconds was measured. The rate of change in hardness is the ratio (%) of the increase in surface hardness measured at 5 ° C. relative to the surface hardness measured at 20 ° C., and is determined from the following equation.
Hardness change rate (%) = ((hardness measured at 5 ° C.−hardness measured at 20 ° C.) × 100) / hardness measured at 20 ° C.

(Static spring constant)
The static spring constant is a load test based on the performance test method for the pad material of the automobile seat of JASO automotive standard B408-89. As the pressure plate, a disk shape having a diameter of 200 ± 2 mm and a thickness of 50 to 100 mm is used. Place the test piece on the horizontal platform of the tester and place the pressure plate attached to the tester on the center of the upper surface of the tester. As pre-compression, compress once with a load of 700 N, leave the load for 3 to 5 minutes, add an initial load of 5 N, measure the thickness (t0), and use this as the initial thickness. The center point on the pressing surface at this time is set as the origin, and after the load meter is set to 0, pressurization and decompression are performed at a speed of 150 to 300 mm / min, and the deflection with respect to the load is measured. A load-deflection curve diagram is created for the relationship between load and deflection from the measurement results.
The static spring constant is a value of the tangent of the tangent on the pressure side at each load in the load-deflection curve. Specifically, a load-deflection curve was obtained by the above test, and a static spring constant at a load of 98N was obtained and evaluated.

(Body pressure dispersibility)
The average seating pressure was 400 mm in length and width, and a polyurethane foam with a height of 100 mm and a subject with a height of 165 cm and a weight of 65 kg was seated in the center of the foam. (Registered trademark) -8).

Formulation example in which the foam obtained by foaming to a thickness of 100 mm has a density of 20 to 80 kg / m ³ , a 25% hardness (ILD hardness) of 30 to 140 N / 314 cm ² and a rebound resilience of 5 to 30%. Since Examples 1 to 8 in which the first polyurethane foams 1 to 6 and the second polyurethane foams of Formulation Examples 8 to 9 are integrally molded have a static spring constant of 10 N / mm or less, as shown in Table 3, The soft feeling of the surface is good and the Sag-Factor is 3.3 or more, so the feeling of bottoming is small when sitting, and the average sitting pressure is 70 mmHg or less, reducing the burden on the human body when sitting. Is done.

In Comparative Example 1 in which the first polyurethane foam of Formulation Example 7 and the second polyurethane foam of Formulation Example 9 having a 25% hardness (ILD hardness) of 171 N / 314 cm ² are integrally molded, the first polyurethane foam is hard. The static spring constant is 10 N / mm or more, the surface softness is poor, the seating average pressure is 70 mmHg or more, and the burden on the human body at the time of sitting is not reduced.

  The laminated flexible polyurethane foam obtained by the present invention is suitable as a vehicle seat cushion having a good surface soft feeling, a low feeling of bottoming at the time of sitting, and a low seating average pressure.

10 Vehicle seat cushion 11 First polyurethane foam 12 Second polyurethane foam

Claims (7)

A vehicle seat cushion formed by laminating a first polyurethane foam and a second polyurethane foam, wherein the first polyurethane foam has a density of 20 to 80 kg / m ³ and a 25% hardness of 30 to 140 N / 314 cm. ^{2. The} impact resilience is 4-30%, the second polyurethane foam has a density of 20-80 kg / m ³ , a 25% hardness of 200-350 N / 314 cm ² and a resilience of 40-85%. A vehicle seat cushion in which the thickness ratio of the first polyurethane foam to the total thickness of the first polyurethane foam and the second polyurethane foam is 10 to 70%. The vehicle seat cushion according to claim 1, wherein Sag-Factor represented by the following formula is 4.3 or more.
Sag-Factor = (65% compression hardness / 25% compression hardness)   The vehicle seat cushion according to claim 1 or 2, wherein the first polyurethane foam has an Asker rubber hardness (F type) hardness change rate of 5 ° C to 20 ° C of 100% or less. The vehicle seat cushion according to any one of claims 1 to 3, wherein the first polyurethane foam and the second polyurethane foam are laminated, wherein the first polyurethane foam and the second polyurethane foam are molded metal. Vehicle seat cushion obtained by molding with a mold. The first polyurethane foam is a soft product obtained by reacting the following polyol (A) and a polyol mixture containing the following polyol (B) with a polyisocyanate compound in the presence of a foam stabilizer, a urethanization catalyst, and a foaming agent. Polyurethane foam,
The polyol (A) has an average number of hydroxyl groups of 2 to 3, a hydroxyl value of 5 to 90 mgKOH / g, a total unsaturation of 0.1 mmol / g or less, and an oxyethylene group content of all oxyalkylene groups (100 mass). %) Polyether polyol of 60% by mass or less,
The polyol (B) is a polyether polyol having an average number of hydroxyl groups of 2 to 4, a hydroxyl value of 15 to 250 mgKOH / g, and excluding the polyol (A). Vehicle seat cushions.   The vehicle seat according to claim 5, wherein in the polyol mixture, the polyol (A) is a polyol (A) obtained by ring-opening polymerization of an alkylene oxide in an initiator using a double metal cyanide complex catalyst. cushion.   The vehicle seat cushion according to claim 5 or 6, wherein the polyol mixture further contains a monool (C) having a hydroxyl value of 10 to 200 mgKOH / g.

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