JP2516526B2 - Method for manufacturing flexible polyurethane foam - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a low-hardness flexible polyurethane foam suitable for automobile seat backs by molding using water alone as a foaming agent.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of using water and Freon 11 or water and Freon 123 as a foaming agent in order to obtain a molded article having a low hardness in a flexible polyurethane foam for an automobile seat back. As the polyether polyol, a polyether polyol having 3 to 4 hydroxyl groups is usually widely used. (For example, Japanese Examined Patent Publication No. 63-57449).

[0003]

However, in the production method in which water and flon 11 or water and flon 123 are used as the foaming agent in combination, the flon destroys the ozone layer [the ozone depletion potential (ODP) of flon 11 = 1). , Freon 123
ODP = 0.021]. Further, when a conventional polyether polyol is used and molded by water alone, there is a problem that a molded product having a low hardness suitable for an automobile seat back cannot be obtained due to an increase in urea bond.

[0004]

Means for Solving the Problems As a result of intensive studies to solve these problems, the inventors of the present invention did not use CFC 11 and CFC 123 that destroy the ozone layer as a foaming agent at all, and used the ozone layer. The present invention has been accomplished by finding a method for producing a flexible polyurethane foam having a low hardness, which is suitable for automobile seat backs, using only water that does not break.

That is, the present invention provides a method for producing a flexible polyurethane foam by reacting a polyether polyol (a) with an organic polyisocyanate (b) in the presence of a catalyst, a foam stabilizer and a foaming agent (c). The polyether polyol (a) comprises the following (a1) to (a3),
Weight ratio of (a1) and (a2) in (a) (a1) /
(A2) is 90/10 to 70/30, (a1) and (a
The ratio of the total weight of 2) to the weight of (a3) [(a1) + (a
2)] / (a3) is 80/20 to 60/40, and the blowing agent (c) is water alone, which is a method for producing a flexible polyurethane foam. (A1): Number of hydroxyl groups is 3 and 10 to 25% by weight at the end
Having a polyoxyethylene chain of 40 to 60 and a hydroxyl value of 40 to 60
Polyether polyol. (A2): Polyoxypropylene polyol having 3 hydroxyl groups and a hydroxyl value of 48-60. (A3): A polyoxypropylene polyol having two hydroxyl groups and a hydroxyl value of 90 to 142.

Examples of the polyether polyol (a1) used in the present invention include compounds having a structure in which an alkylene oxide is added to a compound having 3 active hydrogen atoms (for example, alcohols and amines).
Examples of alcohols include alcohols such as glycerin and trimethylolpropane. Further, diethanolamine and other alkanolamines and amines having three active hydrogens can be mentioned. Of these, alcohols are preferable. As the alkylene oxide to be added to the compound having 3 active hydrogen atoms,
They are ethylene oxide (hereinafter abbreviated as EO) and other alkylene oxides [propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3-, 1,4-, 2,3-butylene oxide, etc.]. (A1) is mainly produced by adding another alkylene oxide and then adding EO.
Another preferred alkylene oxide is PO. The number of functional groups in (a1) is 3. If it is less than 3, the curing time will be long, the productivity will be poor, and the compression set will be poor. When the number of functional groups exceeds 3, the low-hardness foam which is the object of the present invention cannot be obtained. The hydroxyl value of (a1) is 40
-60. When the hydroxyl value exceeds 60, the allowable range of the amount of the catalyst used becomes narrow and the practicality is poor, and the low hardness foam which is the object of the present invention cannot be obtained. If the hydroxyl value is less than 40, the compression set will be poor, the curing time will be long, and the productivity will be poor. The amount of EO added in (a1) is 10 to 25% by weight. If the amount of EO added is less than 10% by weight, the curing time will be long and the productivity will be poor. When the amount of EO added exceeds 25% by weight, the allowable range of the amount of catalyst used is narrowed and the practicality is poor.

Examples of the polyether polyol (a2) used in the present invention include compounds having a structure in which PO is added to compounds having 3 active hydrogen atoms (for example, alcohols and amines). Examples of alcohols include alcohols such as glycerin and trimethylolpropane. Further, diethanolamine and other alkanolamines and amines having three active hydrogens can be mentioned. Of these, alcohols are preferable. The alkylene oxide added to the active hydrogen atom compound is PO, but EO, 1,2-, 1,
3-, 1,4-, 2,3-butylene oxide, etc.
You may use together 10 weight% or less with respect to O. The number of functional groups in (a2) is 3. When the number of functional groups exceeds 3, the low-hardness foam which is the object of the present invention cannot be obtained. If the number of functional groups is less than 3, the compression set will be poor, the curing time will be long, and the productivity will be poor. The hydroxyl value of (a2) is 48-60. When the hydroxyl value exceeds 60, the low hardness foam which is the object of the present invention cannot be obtained. When the hydroxyl value is less than 48, the compression set becomes worse, the curing time becomes longer, and the productivity becomes worse.

Examples of the polyether polyol (a3) used in the present invention include compounds having a structure in which PO is added to a compound having two active hydrogen atoms (for example, alcohols and amines). Alcohols are preferable as the active hydrogen atom compound, and examples of alcohols include alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol and neopentyl glycol. The alkylene oxide added to the active hydrogen atom compound is PO, but E
O, 1,2-, 1,3-, 1,4-, 2,3-butylene oxide or the like may be used in combination with PO in an amount of 5% by weight or less. The number of functional groups in (a3) is 2. When the number of functional groups exceeds 2, the low hardness foam which is the object of the present invention cannot be obtained. If the number of functional groups is less than 2, the compression set is poor, the curing time is long, and the productivity is poor. The hydroxyl value of (a3) is 90 to 142. If the hydroxyl value is less than 90, the compression set will be poor, the curing time will be long, and the productivity will be poor. When the hydroxyl value exceeds 142, the foam having a low hardness, which is the object of the present invention, cannot be obtained, and the permissible range of the amount of the catalyst used becomes narrow, resulting in poor practicability. The average number of functional groups in (a1) to (a3) may be smaller than the number of active hydrogens in the adduct due to side reactions during the alkylene oxide addition reaction.

Polyol (a) used in the present invention
The composition therein consists of (a1), (a2), and (a3) above. The weight ratio (a1) / (a2) of (a1) and (a2) is 90/10 to 70/30, preferably 90/10.
~ 80/20. When (a1) exceeds 90, the allowable range of the amount of catalyst used becomes narrow and the practicality is poor, and the foam of low hardness which is the object of the present invention cannot be obtained. Become. The ratio of the total weight of (a1) and (a2) to the weight of (a3) [(a1) +
(A2)] / (a3) is 80/20 to 60/40, preferably 75/25 to 65/35. (A
If 3) exceeds 40, the compression set deteriorates, and if it is less than 20, the low-hardness foam object of the present invention cannot be obtained.

As the organic polyisocyanate (b) used in the present invention, those generally used for polyurethane are used. For example, an aromatic polyisocyanate having 6 to 20 carbon atoms (excluding the carbon number in the NCO group) [2,4
-, 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4-, 4,4-diphenylmethane diisocyanate (MDI), crude MDI [crude diaminophenylmethane {formaldehyde and aromatic amine (e.g. aniline) or its Condensation product with a mixture; diaminodiphenylmethane and a small amount (eg 5 to 20% by weight) of 3
A polyisocyanate obtained by phosgenating a mixture with a polyamine having a functionality or more}, a polyaryl polyisocyanate (for example, PAPI)]], etc .;
Aliphatic isocyanate [hexamethylene diisocyanate, lysine diisocyanate, etc.]; C4-15
Alicyclic polyisocyanates [isophorone diisocyanate, dicyclohexyl diisocyanate, etc.]; Aroaliphatic polyisocyanates having 8 to 15 carbon atoms [xylylene diisocyanate, etc.]; Modified products of these polyisocyanates [urethane group, carbodiimide group, allophanate group , Urea group, burette group, uretdione group, uretonimine group, isocyanurate group, oxazolidone group-containing modified product, etc.]; Japanese Patent Application No. 59-199160.
Polyisocyanates other than the above described in Japanese Patent Publication; and mixtures of two or more thereof. Of these, preferred are 2,4- and 2,6-TDI, and mixtures of these isomers.

As the foam stabilizer used in the present invention, those for soft urethane foam are usually used. Examples thereof include dimethylsiloxane-based foam stabilizers, and specifically, L-540 and L-52 manufactured by Nippon Unicar Co., Ltd.
0, SZ-1142, SRX-294A manufactured by Torre Dow Corning Silicone Co., Ltd., and the like.

Known catalysts can be used in the present invention. Specifically, metal salts of carboxylic acids, for example, sodium acetate, lead octylate, zinc octylate,
Cobalt naphthenate, stannas octoate, etc .; alkali and alkaline earth metal alkoxides and phenoxides (eg sodium methoxide, sodium phenoxide); tertiary amines (eg triethylamine,
Triethylenediamine, N-methylmorpholine, dimethylaminomethylphenol, pyridine); quaternary ammonium bases (eg tetraethylammonium hydroxide); imidazoles (eg imidazole, 2-ethyl-4-methylimidazole); tin and antimony, etc. Organometallic compounds (for example, tetraphenyl tin, tributyl antimony oxide) can be mentioned. Of these, organometallic compounds such as tin and antimony and tertiary amines are preferable.

The blowing agent (c) used in the present invention is water. Although it is possible to use a foaming agent other than water in combination, it is preferable to use a foaming agent (for example, methylene chloride) which does not violate the purpose of preventing the destruction of the global environment of the method of the present invention.

The amount of each additive (foaming agent, foam stabilizer and catalyst) used in the present invention is as follows based on 100 parts by weight of the polyol. The amount of water used as a foaming agent is not particularly limited, but is usually 2 to 8 parts by weight, preferably 3 to 7 parts by weight. The amount of the foam stabilizer is usually 0.5 to
It is 5 parts by weight, preferably 1 to 3 parts by weight. The amount of the catalyst used is usually 0.01 to 3 parts by weight, preferably 0.05 to 2
Parts by weight. The amount of organic polyisocyanate used is NC
The O index is usually 70 to 120, preferably 80 to 1.
It is 10. The production method of the flexible polyurethane foam in the present invention is usually a hot cure method in which the mold temperature is 30 to 45 ° C.

[0015]

The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

Examples 1 to 5 and Comparative Examples 1 to 3 Urethane foams were foamed in a mold with the foaming formulations shown in Tables 1 and 2 (the numbers in the tables indicate parts by weight), After being placed in a dryer and cured, the urethane foam was taken out of the mold to obtain a flexible polyurethane foam. The results of measuring the physical properties are shown in Tables 1 and 2.

According to the method of the present invention, the foam obtained by using water alone as the blowing agent and using the polyol component (a) in the method of the present invention is
It is possible to obtain a foam having a low hardness equivalent to that of a conventional foam that also uses Freon 11. In addition, it can be seen that the other foam physical properties also have sufficient performance for automobile seat backs.

(Foaming conditions) Mold shape: 300 mm × 300 mm × 70 mm Material: Aluminum Mold temperature: 30-45 ° C. Mixing method: Low pressure machine mixing Raw material temperature: 25 ± 2 ° C. Cure condition: 150 ° C. × 10 minutes

(Raw materials used) Polyol (a1): PO-EO adduct of glycerin having a hydroxyl value of 56.1, EO addition amount of 20% by weight. Polyol (a2): PO adduct of glycerin having a hydroxyl value of 56.1. Polyol (a3): PO adduct of propylene glycol having a hydroxyl group value of 118.1. Polyol (b1): PO-EO adduct of glycerin having a hydroxyl value of 56.1, EO addition content 12% by weight. Polyol (b2): A mixture of PO-EO adduct of pentaerythritol having a hydroxyl value of 44.9 and PO-EO-PO-EO of glycerin having a hydroxyl value of 56.1 (mixing weight ratio = 70/30). T-80: Nippon Polyurethane Industry Co., Ltd., 2,4-
A mixture of / 2,6-tolylene diisocyanate (mixing weight ratio = 80/20). DABCO 33LV: 33% dipropylene glycol solution of triethylenediamine. NMM: N-methylmorpholine. TOYOCATF4: A tertiary amine catalyst manufactured by Tosoh Corporation. L-520: Nippon Unicar Co., Ltd. dimethyl siloxane-based foam stabilizer.

The method for measuring the physical properties of foam is JIS K640.
1 and the unit is as follows. Core-Density ・ ・ ・ ・ Kg / m ³ 25% ILD hardness ・ ・ ・ ・ Kg / 314cm ² Compression set ・ ・ ・ ・ ・ ・ (%) Rebound resilience ・ ・ ・ ・ (%) Tensile strength ・ ・ ・ ・Kg / cm ² Cutting elongation ・ ・ ・ ・ (%) Tear strength ・ ・ ・ ・ Kg / cm

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

In order to obtain a low hardness polyurethane foam for automobile seat backs by using the conventional polyether polyol, it has been indispensable to use Freon 11 and Freon 123 together with water as a foaming agent. . However, by using the polyol composition for a flexible polyurethane foam of the present invention, CFC 11 and CFC 12 can be used.
Without using 3, it is possible to obtain a polyurethane foam having a low hardness suitable for an automobile seat back even with water alone. In addition, CFC 1 that destroys the ozone layer as a foaming agent
1. Since water alone is used without using Freon 123, there is no problem of environmental destruction of the earth.

Front Page Continuation (72) Inventor Kijuzo Sasaki 1 Toyota-cho, Toyota-shi Ltd. Toyota Motor Co., Ltd. (72) Inventor Yukio Iwata 1-cho, Toyota-cho Toyota-shi In Toyota Motor Co., Ltd. (72) Inventor Matsunaga Minoru 1-11, Hitotsubashi Honcho, Higashiyama-ku, Kyoto Sanyo Kasei Kogyo Co., Ltd. (72) Inventor Motohisa Kaku 1-11, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto Sanyo Kasei Co., Ltd. (72) Inventor Keiichi Akimoto 1 Sanyo Kasei Kogyo Co., Ltd., 1-11, Hitotsubashi-honcho, Higashiyama-ku, Kyoto (56) Reference JP-A-57-195725 (JP, A) JP-A-54-93098 (JP, A) JP-A-4-359917 (JP, A) JP 57-5715 (JP, A) JP 62-256814 (JP, A) JP 51-145597 (JP, A) JP 44-16914 (JP, B1)

Claims (1)

(57) [Claims] 1. A method for producing a flexible polyurethane foam by reacting a polyol component (a) with an organic polyisocyanate (b) in the presence of a catalyst, a foam stabilizer and a foaming agent (c), wherein the polyol component (a) ) Is the following (a1)
(A3), the weight ratio (a1) / (a2) of (a1) and (a2) in (a) is 90/10 to 70/30,
The weight ratio [(a1) + (a2)] / (a3) of the total weight of (a1) and (a2) and (a3) is 80/20 to 60.
/ 40, and the foaming agent (c) is water alone, a method for producing a flexible polyurethane foam. (A1): Number of hydroxyl groups is 3 and 10 to 25% by weight at the end
Having a polyoxyethylene chain of 40 to 60 and a hydroxyl value of 40 to 60
Polyether polyol. (A2): Polyoxypropylene polyol having 3 hydroxyl groups and a hydroxyl value of 48-60. (A3): Polyoxypropylene polyol having 2 hydroxyl groups and 90-142 hydroxyl values.