JP2005320437A - Urethane foam for automobile seats - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automobile seat urethane foam having a high material property using a plant-derived raw material.
A urethane foam obtained by reacting at least a polyol and an isocyanate compound, wherein the polyol is obtained by adding at least one molecule of alkylene oxide to a vegetable oil and fat, and at the end of the molecular chain. The following structure having an ethyl group was used.
[Chemical 1]

Description

  The present invention relates to a urethane foam often used for automobiles, and more particularly to a urethane foam for automobile seats using vegetable oil as a polyol as a raw material component of urethane foam.

  Conventionally, as a polyol used for urethane foam for automobiles, a polyether polyol which is a petroleum-derived material is typically used, and examples thereof include polypropylene glycol (PPG) and polytetramethylene ether glycol (PTG). These polyols are refined from petroleum. For example, an automobile seat cushion using a specific polyol has been proposed (see Patent Document 1). By the way, the urethane foam for automobiles is shredded and incinerated at the time of waste car treatment. Therefore, incineration of petroleum raw material urethane foam as in Patent Document 1 generates carbon dioxide, which causes global warming. Therefore, there is a demand for urethane foam that can suppress an increase in carbon dioxide during incineration.

  If the polyol, which is a raw material component of urethane foam, is used as a plant-derived raw material, even if carbon dioxide is generated by incineration, if it is a plant-derived raw material originally produced by photosynthesis from carbon dioxide, the increase in carbon dioxide is It is possible that global warming can be prevented. Various methods for polymerizing polyols from plant-derived raw materials have been studied (see Patent Documents 2, 3, 4 and Non-Patent Document 1).

Patent Document 2 discloses a polyurethane foam using castor oil and aerated soybean oil as a polyether material as a plant-derived raw material, and Patent Documents 3 and 4 disclose an alcohol ring-opened product of epoxidized soybean oil. Polyurethane foams used as polyether materials are disclosed. In Non-Patent Document 1, a waste soybean oil is used as a raw material and 65% sulfuric acid and 30% hydrogen peroxide water are mixed and heated to introduce a hydroxyl group into the double bond portion of the soybean oil, thereby purifying the polyol. A method for producing a urethane foam by mixing and stirring polymeric diisocyanate (PMDI), water, an amine catalyst, and a silicone foam stabilizer is disclosed.
JP 7-206961 A JP-T-2002-524627 JP 59-207914 A JP 63-415123 A Katsuharu Matsunaga, Masakazu Ogura 2002 Toyo University Master's Thesis Collection

  The polyurethane foams described in Patent Documents 2 to 4 are derived from plants and are expected to reduce the amount of carbon dioxide emitted by incineration, but their rebound resilience is insufficient and cannot be used as cushions for automobile seats.

  Similarly, Non-Patent Document 1 can produce urethane foam from plant-derived raw materials (soybean oil), but it is also unsuitable for automobile applications. This is because the urethane foam has a rebound resilience (JIS K 6400) of 1%, which is far from the target value of 40% or more for automobile applications. Rebound resilience is the most important characteristic of cushioning materials for automobiles. If the impact resilience is low, there is a feeling of bottoming if the urethane foam is not thickened, and if the foam is hardened to eliminate the feeling of bottoming, it feels comfortable to sit on. Getting worse. Increasing the thickness of the foam is not preferable because it leads to a narrow space in a limited automobile. The compression set (50% compression of JIS K 6400) is 47%, which is far from the target value of 20% or less for automobile applications.

  By the way, castor oil contains 90% ricinoleic acid. Since ricinoleic acid has one hydroxyl group, castor oil is a 2.7-valent natural polyol. However, the molecular weight is about 930, and the molecular weight is too low to achieve the target physical properties (see the conventional example in Table 1). In order to improve the properties of urethane foam, castor oil and polyoxypropylene triol (PPT) produced from petroleum are blended in the proportions shown in Table 1, and toluene diisocyanate (TDI), blowing agent (water), catalyst (amine system, tin system) ) And a foam stabilizer (silicone type) were added to produce urethane foam, and physical properties were examined. However, the rebound resilience of 40% or more, which is the target value, could not be satisfied (see Table 1).

  This invention is made | formed in view of the above subjects, and it aims at providing the urethane foam for motor vehicle seats which has a high resilience elastic modulus using a plant-derived raw material.

  More specifically, the present invention provides the following.

  (1) A urethane foam for automobile seats obtained by reacting at least a polyol and an isocyanate compound, wherein the polyol is obtained by adding at least one molecule of alkylene oxide to vegetable oil and fat, and has a molecular chain terminal. Is a urethane foam for automobile seats, which is a hydroxyethyl group.

  According to the invention of (1), even if vegetable oils and fats are used as a raw material for polyols, it is possible to secure a flexible, foam resilience-rich urethane foam property and to reduce carbon dioxide emissions during incineration. Is possible. In addition, at least one molecule of alkylene oxide is added to this vegetable oil and the end of the molecular chain is a hydroxyethyl group, whereby the carbon at the end of the molecular chain becomes a primary carbon. As a result, a polyol having a high reactivity of the hydroxyl group at the end of the molecular chain is obtained, so that good moldability can be obtained without using a large amount of tin catalyst whose use is being limited.

  (2) The urethane foam for automobile seats according to (1), wherein the polyol has a number average molecular weight of 3000 to 5000.

  According to the invention of (2), a polyol having an appropriate viscosity can be obtained by setting the number average molecular weight of the polyol to 3000 to 5000.

  (3) The vegetable oil or fat according to (1) or (2), wherein the vegetable oil or fat is one or more selected from the group consisting of fats and oils containing hydroxy fatty acids including castor oil and rescrela oil, and derivatives thereof. Urethane foam for automobile seats.

  According to the invention of (3), at the time of incineration, the vegetable oil / fat is one or more selected from the group consisting of an oil / fat whose component is a hydroxy fatty acid containing castor oil, rescrela oil, and derivatives thereof. It is possible to provide a urethane foam capable of reducing carbon dioxide emissions.

  (4) The urethane foam for automobile seats according to any one of (1) to (3), wherein the impact resilience is 40% or more and 70% or less.

  According to the invention of (4), it is possible to provide a urethane foam for automobile seats that has no feeling of bottoming out and is comfortable to sit by having a rebound resilience of 40% to 70%.

  (5) The urethane foam for automobile seats according to any one of (1) to (4), which is used for a cushion of an automobile seat.

  According to the urethane foam for automobile seats according to the present invention, even if vegetable oils and fats are used as a raw material for polyols, the urethane foam has an appropriate cross-linked structure and has material properties that can be used for automobile seats. It becomes possible.

  The “automobile” according to the present invention refers to a vehicle that rotates a wheel by the power of a prime mover and runs without depending on a rail or an overhead wire, and particularly refers to a two-wheeled vehicle or a four-wheeled vehicle. The “polyol” according to the present invention is a product obtained by adding at least one molecule of alkylene oxide to vegetable oil and fat, and has a molecular chain terminal having a hydroxyethyl group. Here, the “vegetable oil / fat” refers to a fatty oil obtained by mainly squeezing plant seeds or leaching with a solvent to purify, decolorize and deodorize. The vegetable fats and oils include oils and fats containing hydroxy fatty acids such as castor oil and rescrela oil, and transesterification products obtained by reactions such as oxidation polymerization and polyhydric alcohols (including compounds such as polyalkylene glycols). Hydroxy fatty acid-containing derivatives obtained by a generally known method may be used, but it is more preferable to use castor oil directly on the market at a low cost because no processing is required.

  Further, the “polyol” according to the present invention preferably has a molecular weight of 3000 to 5000. This is because when the molecular weight is 3000 or less, the low resilience rate of the urethane foam is hardly 40% or more. Further, as shown in Table 2, even if the molecular weight of the polyol is 5000 or more, it is possible to ensure the physical properties of the urethane foam, but the ratio of plant-derived raw materials is reduced. Moreover, a viscosity rise is large and a moldability will fall. In addition, since the physical properties of urethane foam depend on the hydroxyl group of the polyol, the number is preferably 2 to 4, and castor oil having three hydroxyl groups is further used for the moldability of the urethane foam. preferable. Specifically, those represented by the following structural formula are preferable.

  The polyol according to the present invention is a product obtained by adding at least one molecule of alkylene oxide to vegetable oil. Among the alkylene oxides, it is preferable to use low molecular weight ethylene oxide and propylene oxide which are particularly excellent in reactivity. Here, the molecular chain terminal of the polyol according to the present invention further has a hydroxyethyl group. In order to add a hydroxyethyl group to the molecular chain terminal, it is preferable to add a cyclic ether such as ethylene oxide. The molar ratio of ethylene oxide to propylene oxide is preferably 2/1 to 1/70, more preferably 2/1 to 1/40. When the molar ratio is larger than 2/1, the resilience modulus is lowered. On the other hand, if the molar ratio is less than 1/70, the reactivity with isocyanate is lowered, and a uniform urethane foam cannot be produced unless a large amount of tin catalyst whose use is being restricted is used.

A known method may be used for the polymerization of the polyol, for example, after adding a catalyst to the vegetable oil and fat, dehydrating under reduced pressure and raising the temperature to a predetermined temperature, and then adding propylene oxide in portions at a predetermined pressure. Ethylene oxide is added in portions under a predetermined pressure, further neutralized with a neutralizer, neutralized and dehydrated, and then filtered to remove salts. In addition, as a catalyst added at this time, it is still more preferable to use alkali metal hydroxide like potassium hydroxide, for example. In this case, the addition amount is preferably 0.05 to 1.0% by mass. The polymerization temperature is not particularly limited, but is usually from 0 ° C to 300 ° C, preferably from 80 ° C to 150 ° C, and more preferably from 100 ° C to 130 ° C. Although the pressure is not particularly limited, it is usually preferably ² to 7 kg / cm ² , more preferably 2.5 to 6 kg / cm ² . The polymerization time is not particularly limited, but is preferably 2 hours to 10 hours. Furthermore, it is preferable to add to the neutralizing agent an inorganic acid such as phosphoric acid or hydrochloric acid or an organic acid such as acetic acid or oxalic acid in an amount of 1 to 2 times the neutralization equivalent of the catalyst.

  Furthermore, the “isocyanate compound” refers to an aromatic polyisocyanate and an aliphatic polyisocyanate containing two or more isocyanate groups in the molecule or a modified product thereof. Specific examples include aliphatic diisocyanates, aliphatic cyclic diisocyanates, aliphatic-aromatic isocyanates, aromatic diisocyanates, tetraisocyanates, polyisocyanates, or mixtures thereof.

  Aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate , Ethylidene diisocyanate, butylidene diisocyanate, and the like.

  Aliphatic cyclic diisocyanates include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-cyclohexane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, and the like.

  Aliphatic-aromatic isocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-biphenyl diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-toluene diisocyanate or a mixture thereof, 4,4'-toluidine diisocyanate, 1,4-xylene diisocyanate and the like can be mentioned.

  Examples of aromatic diisocyanates include dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and chlorodiphenyl diisocyanate. Examples of triisocyanates include triphenylmethane-4,4 ', 4 "-triisocyanate, 1,3,5 -For tetraisocyanates such as triisocyanate benzene and 2,4,6-triisocyanatotoluene, for polyisocyanates such as 4,4'-diphenyl-dimethylmethane-2,2 ', 5,5'-tetraisocyanate May include toluene diisocyanate dimer, toluene diisocyanate trimer, etc., among which toluene diisocyanate (TDI) is preferably used.

  The “urethane foam” according to the present invention is produced by a known production method such as a slab method, a one-shot method, a semi-premer method, and a prepolymer method. Water, an organic foaming agent, an inorganic foaming agent, air, carbon dioxide, etc. can be used as the foaming agent. Examples of the organic foaming agent include acetone, dichloromethane, nitroalkane, nitrourea, aldoxime, active methylene compound, acid amide, tertiary alcohol, and oxalic acid hydrate. Examples of the inorganic foaming agent include boron. Acid, solid carbonic acid, aluminum hydroxide and the like can be mentioned, but water is preferably used.

  Moreover, as a catalyst for adjusting the reaction rate of a polyol and isocyanate, the catalyst normally used for manufacture of a polyurethane, for example, a tertiary amine, a reactive amine, etc. are mentioned. Specifically, tertiary amines include triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, 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 -Dimethylimidazole, 1-butyl-2-methylimidazole, etc. Reactive amines include dimethylethanolamine, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanol. Amines, etc. These organic acid salts, stannous octoate, dibuty Carboxylic acid metal salts such as rutin dilaurate, potassium acetate and potassium 2-ethylhexanoate, organometallic compounds such as dibutyltin dilaurate and stannous octoate (in addition, aluminum and tin), etc. may be used. Is preferably 0.01 to 10% by mass, and more preferably 0.3 to 2% by mass.

  Examples of the foam stabilizer include foam stabilizers commonly used in the production of polyurethane, such as silicone foam stabilizers and fluorine foam stabilizers, but it is preferable to use silicone foam stabilizers.

  In addition to the above, active hydrogen compounds, crosslinking agents, light stabilizers, plasticizers, antioxidants, thermal stabilizers, fillers, anti-coloring agents, pigments, and other additives can be added as necessary. It is.

  Hereinafter, the present invention will be described in more detail, but the present invention is not limited to these examples.

[Sample 1: Synthesis of polyol]
After adding 0.85 g of potassium hydroxide (KOH) to 100 parts of castor oil, the mixture was dehydrated under reduced pressure and heated to 110 ° C. To this, 331 parts of propylene oxide was added in portions while maintaining a reaction pressure of 4 kg / cm ² . After completion of the addition, the pressure gradually decreased, but the reaction was continued until no pressure drop was observed. Next, 37 g of ethylene oxide is dividedly added so as to maintain the reaction pressure of 4 kg / cm ² in the same manner. After completion of the addition, the pressure gradually decreased, but the reaction was continued until no pressure drop was observed. To this reaction product, 1.1 g of phosphoric acid was added, and the catalyst was neutralized and dehydrated, followed by filtration to remove the salt to obtain a polyol (sample 1) having a hydroxyl value of 37 mgKOH / g. The molecular weight determined by gel permeation chromatography (GPC) was 5000.

[Sample 2: Synthesis of polyol]
After adding 0.48 g of KOH to 100 parts of castor oil, it was dehydrated under reduced pressure and heated to 110 ° C. To this, 138 parts of propylene oxide was divided and charged while maintaining a reaction pressure of 4 kg / cm ² . After completion of the addition, the pressure gradually decreased, but the reaction was continued until no pressure drop was observed. Next, 24 g of ethylene oxide is dividedly added so as to maintain a reaction pressure of 4 kg / cm ² in the same manner. After completion of the addition, the pressure gradually decreased, but the reaction was continued until no pressure drop was observed. The reaction product was added with 0.77 g of phosphoric acid to neutralize the catalyst, dehydrated, and filtered to remove the salt to obtain a polyol (sample 2) having a hydroxyl value of 66 mgKOH / g. Moreover, the molecular weight by GPC measurement was 3000.

[Sample 3: Synthesis of polyol]
After adding 0.85 g of KOH to 100 parts of castor oil, it was dehydrated under reduced pressure and heated to 110 ° C. To this, 284 parts of propylene oxide was divided and added while maintaining a reaction pressure of 4 kg / cm ² . After completion of the addition, the pressure gradually decreases, but the reaction is continued until no pressure drop is observed. To this reaction product, 1.36 g of phosphoric acid was added, the catalyst was neutralized, dehydrated, and filtered to remove the salt to obtain a polyol (sample 3) having a hydroxyl value of 45 mgKOH / g. Moreover, the molecular weight by GPC measurement was 5000.

[Sample 4: Synthesis of polyol]
After adding 0.48 g of KOH to 100 parts of castor oil, it was dehydrated under reduced pressure and heated to 110 ° C. To this, 162 parts of propylene oxide was divided and charged while maintaining a reaction pressure of 4 kg / cm ² . After completion of the addition, the pressure gradually decreased, but the reaction was continued until no pressure drop was observed. The reaction product was added with 0.77 g of phosphoric acid to neutralize the catalyst, dehydrated, and filtered to remove the salt to obtain a polyol (sample 4) having a hydroxyl value of 65 mgKOH / g. Moreover, the molecular weight by GPC measurement was 3000. Table 3 shows the molecular weight and ethylene oxide (EO) / propylene oxide (PO) ratio of each sample at this time.

[Examination of polyol reactivity]
The reactivity of Samples 1 to 4 was examined from the change in viscosity of the isocyanate mixture. The isocyanate used (Mitsui Takeda Chemical Co., Ltd. product name: Cosmonate T-80.) Was used. The viscosity was measured by the pot life measurement method under the following conditions.

First, a predetermined amount of polyol, isocyanate and the catalyst shown below were weighed into a 100 ml polycup. At this time, the amount of polyol and isocyanate was determined according to the respective hydroxyl values so that the isocyanate INDEX was 100 and the total was 100 g. Samples 1 and 3 were 95 g polyol and 5 g isocyanate, and samples 2 and 4 were 91 g polyol and 9 g isocyanate. Next, the stopwatch was operated, and these were mixed using a glass rod quickly and for 2 minutes so that bubbles were not mixed as much as possible. At this time, the polycup was covered with a heat insulating material so that the external temperature conditions were the same. Finally, the viscosity of the mixture was measured using a B-type viscometer. In addition, the measurement measured time when viscosity reaches 50000 mPa.s.
<Catalyst>
Addition amount of amine catalyst (NC-IM) 0.260 parts / NCO
Tin-based catalyst (Sn (oct) ₂ ) addition amount 0.017 part / NCO
(INDEX100)

  The relationship between the viscosity and time at this time is shown in FIG. It was shown that a polyol having a smaller molecular weight has higher reactivity with isocyanate, and if the molecular weight is equal, the polyol has higher reactivity by adding ethylene oxide to the molecular terminal. This suggests that the reactivity of the hydroxyl group is improved because the carbon at the end of the molecular chain is a primary carbon.

[Examples and Comparative Examples: Preparation of urethane foam]
A catalyst, a silicone-based foam stabilizer and water were stirred and mixed at room temperature with 100 parts by mass of polyol. Furthermore, after adding isocyanate and stirring and mixing with a homomixer, the mixture was poured into a 70 mm × 350 mm × 350 mm mold and foamed for 20 minutes at a lower mold temperature of 55 ° C. to obtain a flexible polyurethane foam. The rebound elastic modulus of the obtained urethane foam was measured according to JIS K 6400. Table 4 shows the obtained results.

  The catalyst is an amine-based catalyst (trade name: TEDA L-33, manufactured by Tosoh Corporation; GE Silicone: product name: NIAX A-1), and the foam stabilizer is a silicone-based foam stabilizer (Toray Dow Corning Made by Silicone Co., Ltd .: trade name SF2969, Toray Dow Corning Silicone Co., Ltd .: trade name SRX-294A), and isocyanate with polydiphenylmethane-4,4′-diisocyanate polymerization degree 2.8 (manufactured by Mitsui Takeda Chemical Co., Ltd .: Trade name Cosmonate M-200) was used.

  FIG. 2 shows the relationship between the resilience modulus and the molecular weight. From this, it was found that the sample in which ethylene oxide was added to the end of the molecular chain achieved a target resilience of 40%.

It is the figure which showed the relationship between the viscosity of the mixture using the polyol of samples 1-4, and time. It is the figure which showed the relationship between the resilience modulus of the urethane foam of Example 1, 2, Comparative Examples 1, 2, and the prior art example 1, and the molecular weight of a polyol.

Claims (5)

A urethane foam for automobile seats obtained by reacting at least a polyol and an isocyanate compound,
The polyol is a urethane foam for automobile seats in which at least one molecule of alkylene oxide is added to vegetable oil and fat, and the molecular chain terminal is a hydroxyethyl group.   The urethane foam for automobile seats according to claim 1, wherein the number average molecular weight of the polyol is 3000 to 5000.   3. The urethane foam for automobile seats according to claim 1, wherein the vegetable oil is one or more selected from the group consisting of castor oil, fats and oils containing hydroxy fatty acids including rescrela oil, and derivatives thereof. .   The urethane foam for automobile seats according to any one of claims 1 to 3, having a rebound resilience of 40% to 70%.   The urethane foam for automobile seats according to any one of claims 1 to 4, which is used for a cushion of an automobile seat.

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