JP2892626B2 - Method for producing polyurethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing
The present invention relates to a method for efficiently producing a semi-rigid polyurethane foam having fine cells of 0.9 g / cm ^{3 in} a short time by a reaction injection molding method. The semi-rigid polyurethane foam having such minute cells has an excellent tactile sensation and elasticity, and is used for automobile armrests, handles, console lids, change knobs and the like.

[0002]

2. Description of the Related Art Semi-rigid polyurethane foams are polyisocyanates, relatively high molecular weight compounds containing at least two isocyanate-reactive hydrogens and having an active hydrogen equivalent of 1,000 or more (hereinafter referred to as polyols), mainly. It is manufactured by adding a foaming agent to a bifunctional low-molecular-weight crosslinker having an active hydrogen equivalent of 150 or less, a catalyst, and the like, and injecting the mixture into a mold capable of sealing using a high-pressure polyurethane foaming machine or the like.

[0003] The reaction mixture is foamed and expanded in a mold and then cured, and is removed as a polyurethane molded product. The mold is made of a material with high thermal conductivity to control the reaction temperature,
Generally, a metal mold (hereinafter, referred to as a mold) or a resin mold is used. Conventionally, as a foaming agent, chlorofluorocarbon (hereinafter, referred to as CFC), especially trichlorofluoromethane (CFC-11) is mainly used.
A dense surface layer could be obtained by utilizing the fact that the temperature rise due to the urethane reaction heat was different between the part in contact with the mold and the inside of the molded product, and the temperature rise and the reaction in the part in contact with the mold were slower than in the product.

However, in recent years, it has been found that CFCs destroy the ozone layer in the atmosphere, and the use and restriction of not only CFCs but also HCFCs, which are alternatives to them, are being advanced.

[0005]

In view of both cost and environmental issues, it is considered that water foaming using water is advantageous, and this study has been widely conducted (Japanese Patent Laid-Open No. 5-3).
39338, etc.).

Conventionally, water foaming is mainly used for producing a low-density flexible polyurethane foam having a density of 0.1 g / cm ³ or less (polyurethane resin handbook / edited by Keiji Iwata / Nikkan Kogyo Shimbun / 178- When a polyurethane foam having fine cells having a density of 0.3 to 0.9 g / cm ³ is produced by water foaming, a high-density skin layer is obtained unlike the case of conventional CFC foaming. Is still difficult (Urethans Technology: Oct./Nov. 1994, P3
2). Therefore, in application fields requiring a certain level of wear resistance, such as handles or knobs, the life of parts may be greatly reduced due to wear.

[0007] In order to improve the abrasion resistance of the polyurethane resin, a prepolymer of polytetramethylene glycol and MDI has been conventionally used (JP-A-6-32205).
7) It has been proposed to use a polyester polyol or a high-molecular-weight polyether having a molecular weight of 5,000 or more as a polyol component, or to use a polyurethane having excellent elongation or strength as disclosed in JP-A-5-295074. Results have not been obtained.

[0008]

SUMMARY OF THE INVENTION The present invention provides a polyisocyanate, a polyol, a catalyst, a blowing agent, and
From a mixture of a crosslinking agent, an internal mold release agent, a reinforcing agent and other auxiliaries, a density of 0.3 to 0.9 is obtained by a reaction injection molding method.
The present invention relates to a method for producing a semi-rigid polyurethane foam having fine cells having g / cm ³ and excellent abrasion resistance without using Freon as a foaming agent.

As a result of intensive studies to develop a semi-rigid polyurethane foam having excellent abrasion resistance, the abrasion resistance of the semi-rigid polyurethane is relatively high molecular weight and high active hydrogen as conventionally thought. Combination of equivalent polyol and low functional isocyanate (JP-A-295074, JP-A-Hei.
339338) is very difficult to improve by obtaining a molded article giving a higher elongation at break.
It has been found that a significant improvement can be achieved by using a polyfunctional low molecular weight polyol having an active hydrogen equivalent of from 00 to 1000 to produce a molded article having a relatively high degree of crosslinking. Surprisingly, an active hydrogen equivalent of 1500 to 2000 (OH number 28
It has been found that the addition of a polyether polyol having a molecular weight of 3,000 to 6,000 (the latest polyurethane application technology: supervised by Keiji Iwata, CMC, P65) has a considerable adverse effect on abrasion resistance.

The trifunctional polyol having an active hydrogen equivalent of 300 to 1000 according to the present invention has a lower viscosity than conventional polyols, so that it is easy to handle and has excellent mixing with isocyanate. It was found that defects such as cracks and cracks were greatly improved. In order to sufficiently exhibit the performance of the polyol component, an isocyanate containing at least 5% by weight of a trifunctional or higher polyfunctional component was used as an isocyanate to be combined, and was molded with an NCO index of 100 or more. In this case, it was found that a molded article having extremely excellent wear resistance could be obtained, and the present invention was completed.

The present invention is directed to a reaction injection molding method comprising the steps of: preparing a polyol mixture comprising an isocyanate and a polyether-based polyol, a crosslinking agent, a catalyst, a foaming agent and, if necessary, an internal release agent, a reinforcing agent and other auxiliaries. by a density of 0.3-0.9 g / cm ^3, and the Shore A hardness of 40 to 90
A method for producing a semi-rigid polyurethane foam having minute cells having the following degree: A) The isocyanate contains a trifunctional or higher polyisocyanate, and the content of the trifunctional or higher polyisocyanate is 5% by weight or more of the entire isocyanate. Using an isocyanate, B) 300 to 100 as a polyether-based polyol
0 trifunctional polyether polyol having an active hydrogen equivalent of 0 and an ethylene oxide content of 5 to 30% by weight of the polyol, and an average active hydrogen equivalent of all polyether polyols of 500 to 12
Using a polyether polyol component having a viscosity of 200 to 800 mPas / 25 ° C., 2) to 20 parts by weight of 6) per 100 parts by weight of component B)
D) A process for producing a polyurethane foam, characterized by using a bifunctional crosslinker component having a molecular weight of 1 to 200, and D) molding a mixture of isocyanate and polyol with an NCO index of 100 to 115.

The isocyanates used in the present invention include diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and these polyisocyanates are modified with urethane, carbodiimide, isocyanurate, or allophanate. Modified polyisocyanates, mixtures thereof, and the like.

In the present invention which requires particularly high productivity, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, modified polyisocyanate thereof or a mixture thereof is preferred. Examples of the trifunctional or higher polyisocyanate include polymethylene polyphenyl polyisocyanate and uretonimine-modified diphenylmethane diisocyanate.

Another desirable polyisocyanate is a derivative of hexamethylene diisocyanate. In this case, a molded article excellent in both weather resistance and wear resistance can be obtained. As the trifunctional or higher polyisocyanate, a modified isocyanurate of hexamethylene diisocyanate is desirable, and the content of the modified isocyanurate is 50% by weight or more of the entire isocyanate.
It is more desirable to obtain high productivity.

The amount of trifunctional or higher polyisocyanate is
5% by weight or more, especially 10% by weight or more of the whole polyisocyanate, as long as the molded article is not extremely brittle, for example,
It may be 70% by weight or more. N of polyisocyanate
The CO content is 17-29% by weight, especially 20-25% by weight
It is preferred that The viscosity of the isocyanate is 200
It is preferable that it is -1200 mPas / 25 degreeC.

Examples of the polyether polyol include hydroxyl-containing compounds such as propylene glycol, diethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose; amino- and hydroxyl-containing compounds such as triethanolamine and diethanolamine; and ethylenediamine. Amino group-containing compounds such as diaminotoluene, ethylene oxide,
A polyol containing 2 to 6 hydroxyl groups in a molecule to which an alkylene oxide such as propylene oxide is added, and having an average hydroxyl equivalent of 100 to 3000 may be used. Polymer polyols obtained by addition-polymerizing a vinyl compound to these polyether polyols are also used. However, the amount of the polyether polyol having a hydroxyl equivalent exceeding 1500 is preferably 30% by weight or less, particularly preferably 20% by weight or less.

Further, a hydroxyl group of a polyester polyol obtained by reacting a polycarboxylic acid with a low molecular weight hydroxyl-containing compound, a polycarbonate polyol obtained by ring-opening polymerization of caprolactone, or a polyether polyol is aminated, or A polyether polyamine obtained by hydrolyzing an isocyanate prepolymer, having an average active hydrogen equivalent of 100 to 30.
00 can also be used together.

In the present invention for the purpose of improving abrasion resistance, 40% by weight or more of the total amount of these polyols is added to propylene oxide and alkanolamine or a trifunctional alcohol such as glycerin, trimethylolpropane or triethanolamine. It is necessary to use a polyether polyol having an active hydrogen equivalent of 300 to 1000, which is prepared by adding ethylene oxide. The amount of ethylene oxide based on the total of propylene oxide and ethylene oxide must be 5 to 30% by weight. When the amount of ethylene oxide is less than 5% by weight, when the molded article is released from the mold, the reaction is not completely completed, and the mold becomes dirty, and troubles such as peeling of the skin occur. Conversely, if the amount of ethylene oxide exceeds 30% by weight, bubbles in the molded article become closed cells, and the molded article is easily swelled when the molded article is removed from the mold, resulting in poor productivity. Also, if a large amount of a polyol having four or more functional groups and an active hydrogen equivalent of the above range or a polyol having three or more functional groups and an active hydrogen equivalent of the above range is used in a large amount, the molded article becomes excessively brittle and is not suitable for the present application.

The amount of ethylene oxide is preferably from 5 to 25% by weight, more preferably from 10 to 25% by weight. The amount of the polyether polyol having an active hydrogen equivalent of 300 to 1000 is preferably at least 50% by weight, particularly preferably at least 70% by weight, based on the whole polyether polyol. The average active hydrogen equivalent of the polyether polyol is preferably 500 to 1200, particularly preferably 500 to 700.

As the catalyst, triethylenediamine, pentamethyldiethylenetriamine, 1,8-diazabicyclo-5,4,0-undecene-7, dimethylaminoethanol, tetramethylethylenediamine, dimethylbenzylamine, tetramethylhexamethylenediamine, bis ( Tertiary amines such as 2-dimethylaminoethyl) ether and organic metal compounds such as dibutyltin dilaurate, dibutyltin dimercaptide, tin octoate, and dibutyltin diacetate are used.

The foaming agent is an amine compound containing a primary or secondary amino group, for example, ethylenediamine,
Carbon dioxide adducts of polyamines such as hexamethylenediamine, diethylenetriamine and triethylenetetramine, or alkanolamines such as ethanolamine, N-methylethanolamine, diethanolamine, isopropanolamine and diisopropanolamine are desirable (Japanese Patent Application Laid-Open No. 58-113150). ). A foaming agent can be easily synthesized in a relatively short time by heating the amine compound to 30 to 110 ° C, preferably 50 to 80 ° C, and blowing in 1 to 5 Bar of carbon dioxide while stirring slowly. . The amount of the carbon dioxide adduct is preferably 2 to 10 parts by weight based on 100 parts by weight of the polyol mixture.

Another blowing agent that is desirable to use is
Formic acid. The amount of formic acid is preferably from 0.4 to 2.0 parts by weight per 100 parts by weight of the polyol mixture. Formic acid is used in the blend polyol component in an amount of 3 equivalents or more.
It is necessary that the pH of the polyol mixture, which is neutralized with a secondary amine catalyst and an organic weak base containing active hydrogen, is 8.0 or more. Insufficient neutralization may cause trouble in the molding machine due to the corrosiveness of formic acid. In addition to these blowing agents, low-boiling hydrocarbons, chlorofluorocarbon-based blowing agents, nitrogen gas, air and the like may be used in combination as blowing agents.

However, it is not very preferable to use water as a foaming agent. As the degree of water foaming relative to amine compound foaming increases, the foaming pressure increases, which adversely affects demolding in a short time. However, mixing of water is inevitable in handling raw materials such as addition of a reinforcing agent, but the amount of water must be 0.8% by weight or less, preferably 0.5% by weight or less of the polyol mixture. 0.8% by weight
If more, the foam will swell when removed from the mold in a short time,
Cracks may occur, and the productivity of the polyurethane foam may be reduced accordingly.

Examples of the crosslinking agent include dihydric alcohols having a molecular weight of 61 to 200, for example, ethylene glycol, propylene glycol, butanediol, 1,3-butanediol, hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol. , Dipropylene glycol, polypropylene glycol, and divalent amines such as diethyltoluenediamine, t-butyltoluenediamine, diethyldiaminobenzene, triethyldiaminobenzene, and tetraethyldiaminodiphenylmethane are used as necessary, and alkylene oxide is added to these. Polyether polyols are also used.
No. 9, Japanese Patent Publication No. 1-34527, Japanese Unexamined Patent Publication No.
74325, JP-B-63-47726, and the like. The amount of the crosslinking agent is preferably 2 to 20 parts by weight per 100 parts by weight of the polyether-based polyol.

Examples of the internal release agent include a mixture of a metal salt of a carboxylic acid and an amine (Japanese Patent Publication No. Sho 63-52056), and a reaction product of a polysiloxane and an isocyanate (Japanese Patent Publication No. 58-1983).
1139), a mixture of an amine, an aliphatic carboxylate and a carboxylic acid ester (Japanese Patent Publication No. 55-42091), hydrogenated castor oil (Japanese Patent Publication No. 4-20925), an ester of a fatty acid polyester and a lower alkyl acetoacetate An exchange product (JP-A-5-155969) and the like are used as needed.

The reinforcing agent is a glassy, inorganic or mineral fiber such as milled glass fiber, wollastonite fiber, processed mineral fiber or flake such as mica or glass flake, and is used as necessary. . Alternatively, a glass mat, a glass cloth, or the like may be set in a mold in advance, and then a raw material may be injected to obtain a foam.

Other auxiliaries include foam stabilizers such as silicone foam stabilizers, surfactants, weathering agents such as antioxidants, UV absorbers, stabilizers such as 2,6-di-t-
Butyl-4-methylphenol, tetrakis [methylene 3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, a colorant and the like are used as required.

For the production of polyurethane foam by reaction injection molding, a high-pressure polyurethane foaming machine manufactured by Hennecke,
A reaction injection molding machine such as a high-pressure polyurethane foaming machine for R-RIM manufactured by Polyurethane Engineering is used. At this time, the NCO index needs to be in the range of 100 to 115. NCO index is 100
If the NCO index is less than 115, the abrasion resistance is greatly impaired. On the other hand, if the NCO index exceeds 115, the molded article is too soft at the time of demolding, and the molded article tends to swell after demolding, and the productivity is greatly impaired.

When the mixture of polyisocyanate and polyol is injected into a mold by a reaction injection molding method using a high-pressure polyurethane foaming machine or the like, the raw material is foamed and expanded in the mold and then cured to take out the polyurethane foam. it can.

[0030]

Preferred embodiments of the present invention will be described below with reference to examples. In the examples, parts are parts by weight unless otherwise specified. In the examples, a) moldability, b)
The dimension between arms, c) physical properties and d) abrasion resistance were measured as follows. a) Moldability The presence or absence of peeling of the foam surface during demolding or significant damage to the surface gloss was visually observed and evaluated.

B) Dimensions between arms In order to determine the blistering state when the foam was released from the mold, the interval between the portions where the horn pads formed in advance were fitted was measured. The portion corresponding to the base of the spoke has a large cross-sectional area, and if this portion expands after demolding, the distance between the bases of the spokes where the horn pad is to be attached becomes short, and the horn pad cannot enter.

C) Physical Hardness (Shore A) Hardness was measured according to ASTM D676-59T. Tensile strength Tensile strength was measured according to JIS K-6301. Growth growth was measured in accordance with JIS K-6301.

D) Abrasion resistance The abrasion resistance is as follows. A 45 mm width No. 6 or No. 10 canvas with a 100 g weight attached to the end of a 28 mm diameter molded product is hooked vertically to the molded product, and a stroke of 80 cm is applied. The number of times was measured until the surface of the molded product was scratched by rubbing the upper surface at a speed of times / minute.

REFERENCE EXAMPLE 1 2.39 kg of monoethanolamine was placed in a 10-liter double-jacket pressure-resistant reactor having a rotating blade of 60 rpm.
2.94 kg of N-methylethanolamine and 2.94 kg of monoethylene glycol were added, and the temperature was adjusted to 50 ° C. while stirring.

A carbon dioxide cylinder equipped with a pressure reducing valve was connected to the container, and carbon dioxide reduced to 3.0 atm was supplied to the upper portion of the liquid surface while stirring was continued. The liquid temperature is 9 in about 3 hours
The temperature rose to 0 ° C., then decreased slowly and returned to 50 ° C.
Eight hours after the supply of carbon dioxide, the liquid was withdrawn from the reaction tank, and the weight was measured to be 9.95 kg. This liquid was a stable liquid even at normal temperature, and even when heated to 80 ° C., no abnormal gas was observed, and it could be stored in a 20-liter tin can as it was. When 280 g of this liquid was placed in a 300 cc pressure-resistant vessel equipped with a pressure gauge and heated to 50 ° C. while keeping it sealed, the pressure became 0.17 Bar. Subtracting the pressure generated by air expansion, the vapor pressure of this liquid was only 0.07 Bar.

Example 1 Glycerin was added with propylene oxide and ethylene oxide at a ratio of 87 to 13 and had an OH value of 56 mg KOH / g.
90 parts of a polyether polyol (polyol A) (active hydrogen equivalent: 1000) and ethylene glycol 6.6
Parts, 3.2 parts of the amine compound obtained in Reference Example 1, 0.6 parts of a 33% ethylene glycol solution of triethylenediamine, and 0.05 parts of dibutyltin dilaurate were mixed to obtain 20 kg of a polyol mixture. Table I shows the properties of the polyol A.

7.8 kg of polymethylene polyphenyl isocyanate containing 5% by weight of polynuclear compound and 6 kg of modified diphenylmethane diisocyanate containing 28% by weight of uretonimine were mixed, heated to 50 ° C., and stirred to glycerin. Propylene oxide and ethylene oxide (weight ratio of propylene oxide to ethylene oxide = 9
7/13) and 6.2 kg of a polyether polyol (polyol D) having an OH value of 28 mgKOH / g (active hydrogen equivalent: 2,000) were added slowly, and then kept at 80 ° C. for 3 hours. The resulting polyisocyanate had an isocyanate group content of 21.0% (isocyanate A).
The properties of isocyanate A are shown in Table II.

Each raw material was placed in a tank of a high-pressure polyurethane foaming machine (HK-100, manufactured by Hennecke), and the mixing ratio was 100: 82.8 (weight ratio), and the NCO index was 10
5. The injection amount was 200 g / sec, the mixing pressure was 160 kg / cm ² , and the injection time was 2.25 seconds, and the mixture was poured into an iron passenger car handle mold heated to 55 ° C. After injecting raw material into mold, 6
After 0 seconds, the foam was taken out and the molded article was a) molded,
b) dimensions between arms, c) physical properties and d) abrasion resistance were measured. The results are shown in Table III.

Example 2 The procedure was carried out except that 90 parts of a polyether polyol (polyol B) having an OH value of 92 mgKOH / g (active hydrogen equivalent: 610) in which propylene oxide and ethylene oxide were added to glycerin at a ratio of 75:25 were used. Raw materials were prepared in the same manner as in Example 1. Using the same isocyanate as in Example 1 with a mixing ratio of 100:
94.9 (weight ratio), NCO index 105, discharge rate 200 g / sec, mixing pressure 180 kg / cm ² , injection time 2.
At 25 seconds, a molded article was prepared and evaluated in the same manner as in Example 1 except for the above. The results are shown in Table III.

EXAMPLE 3 8.2 k of a polymethylene polyphenylisocyanate containing 5% by weight of a polynuclear compound with the polyol mixture shown in Example 2
g and 6.4 kg of modified diphenylmethane diisocyanate containing 28% by weight of uretonimine, heated to 50 ° C., and stirred while adding propylene oxide and ethylene oxide (weight ratio of propylene oxide to ethylene oxide = 75/25) to glycerin. ) And OH
5.4 kg of a polyether polyol (polyol B) having a value of 92 mgKOH / g (active hydrogen equivalent 610) is slowly added,
Combined with an isocyanate having an isocyanate group content of 21.0% (isocyanate B) in a mixing ratio of 100: 94.
9 (weight ratio), NCO index 105, discharge amount 20
A molded article was prepared and evaluated in the same manner as in Example 1, except that the mixing time was 0 g / sec, the mixing pressure was 180 kg / cm ² , and the injection time was 2.25 seconds. The results are shown in Table III.

Example 4 The same raw materials as in Example 3 were used, and the mixing ratio was 100: 99.4.
(Weight ratio) A molded product was manufactured and evaluated in the same manner as in Example 3 except that the NCO index was 110. Result III
It is shown in the table.

Example 5 90 parts of a polyether polyol (polyol A) having an OH value of 56 mgKOH / g (active hydrogen equivalent: 1000) obtained by adding propylene oxide and ethylene oxide to the glycerin used in Example 1 at a ratio of 87:13. Of which 45 are O
Replaced with a polyether polyol (polyol F) having an H value of 112 mgKOH / g (active hydrogen equivalent: 500) and a mixing ratio of 10
A molded product was prepared and evaluated in the same manner as in Example 1 except that the NCO index was set to 0: 92.2 (weight ratio) and the NCO index was set to 105. The results are shown in Table III.

EXAMPLE 6 Propylene oxide and ethylene oxide were added to glycerin in a weight ratio of 87 to 13 to produce an OH value of 92 mgKOH / g.
90 parts of a polyether polyol (polyol B) (active hydrogen equivalent: 610), 6.6 parts of ethylene glycol, 0.5 part of formic acid, 1.5 parts of diethanolamine, 0.6 part of a 33% ethylene glycol solution of triethylenediamine and 0.6 parts of dibutyl 0.05 parts of tin dilaurate were mixed to obtain 20 kg of a polyol mixture.

This polyol mixture and isocyanate A
And a mixing ratio of 100: 88.1 (weight ratio), NCO
A molded product was prepared and evaluated in the same manner as in Example 1 except that the index was set to 105. The results are shown in Table III.

EXAMPLE 7 Propylene oxide and ethylene oxide were added to glycerin in a weight ratio of 87 to 13 to produce an OH value of 92 mgKOH / g.
90 parts of a polyether polyol (polyol B) (active hydrogen equivalent 610), 6.6 parts of 1,3-butanediol,
3.2 parts of the amine compound obtained in Reference Example 1 and 0.5 part of dibutyltin dilaurate were mixed to obtain 20 kg of a polyol mixture.

Bayer AG obtained by modifying this polyol mixture and hexamethylene diisocyanate by isocyanuration
A molded product was prepared and evaluated in the same manner as in Example 1 by combining with Desmodur TPLS2025 / 1 (isocyanate C) manufactured by the same company, with a mixing ratio of 100: 70.1 (weight ratio) and an NCO index of 105. The results are shown in Table III.

Example 8 90 parts of polyol B used in Example 7, 9.0 parts of 1,3-butanediol, 3.2 parts of amine compound obtained in Reference Example 1
Were mixed with 1.0 part of dibutyltin dilaurate to obtain 20 kg of a polyol mixture.

A trial product (isocyanate D) of a low-viscosity isocyanurate-modified product in which the polyol mixture and hexamethylene diisocyanate were partially allophanatized and the isocyanate C used in Example 7 were mixed with 30: 7
Combined with isocyanate E mixed at a ratio of 0, mixing ratio 1
00: 81.3 (weight ratio), NCO index 105
In the same manner as in Example 1, a molded article was prepared and evaluated. The result
The results are shown in Table III.

Example 9 Propylene oxide and ethylene oxide were added to the glycerin of the polyol mixture used in Example 8 in a ratio of 87 to 13 to give an OH value of 92 mgKOH / g (active hydrogen equivalent of 61
45 parts of 90 parts of the polyether polyol (polyol B) of 0) were replaced with a polyether polyol (polyol H) having a 0H value of 112 mgKOH / g (active hydrogen equivalent: 500), and the mixture was combined with isocyanate E at a mixing ratio of 10%.
A molded product was prepared and evaluated in the same manner as in Example 1 at 0: 84.4 (weight ratio) and NCO index 105. Result II
It is shown in Table I.

Comparative Example 1 Instead of 90 parts of a polyether polyol having an OH value of 56 mgKOH / g (active hydrogen equivalent: 1000) obtained by adding propylene oxide and ethylene oxide to the glycerin used in Example 1 at a ratio of 87:13, an OH value was used. 28 mg KOH / g (active hydrogen equivalent: 2000) replaced with polyether polyol (polyol D), combined with isocyanate A,
A molded product was prepared and evaluated in the same manner as in Example 1 at a mixing ratio of 100: 73.4 (weight ratio) and an NCO index of 105. The results are shown in Table III.

Comparative Example 2 Instead of 90 parts of polyether polyol having an OH value of 56 mgKOH / g (active hydrogen equivalent: 1000) obtained by adding propylene oxide and ethylene oxide to the glycerin used in Example 1 at a ratio of 87:13, the OH value was changed to 90 parts. Replace with 35 mg KOH / g (active hydrogen equivalent 1600) polyether polyol (polyol E), combine with isocyanate A,
A molded product was prepared and evaluated in the same manner as in Example 1 with a mixing ratio of 100: 75.8 (weight ratio) and an NCO index of 105. The results are shown in Table III.

COMPARATIVE EXAMPLE 3 Instead of 90 parts of a polyether polyol having an OH value of 92 mgKOH / g (active hydrogen equivalent: 610) obtained by adding propylene oxide and ethylene oxide at a ratio of 87:13 to glycerin used in Example 7, propylene glycol was used. OH value 28 mg / KOH / g (active hydrogen equivalent 200
0) with a polyether polyol (polyol G), combined with isocyanate C, at a mixing ratio of 100:
A molded article was prepared and evaluated in the same manner as in Example 1 with an NCO index of 50.9 (weight ratio). The results are shown in Table III.

Comparative Example 4 90 parts of polyol E used in Comparative Example 2, 10 parts of 1,3 butanediol, and 3.2 parts of the amine compound obtained in Reference Example 1
Were mixed with 1.0 part of dibutyltin dilaurate to obtain 20 kg of a polyol mixture. This polyol mixture and isocyanate D were combined and mixed at a mixing ratio of 10
A molded product was prepared and evaluated in the same manner as in Example 1 at 0: 95.3 (weight ratio) and NCO index 105. Result III
It is shown in the table.

Comparative Example 5 Instead of 90 parts of 56 mg KOH / g (active hydrogen equivalent: 1000) polyether polyol obtained by adding propylene oxide and ethylene oxide in a ratio of 87:13 to the glycerin used in Example 1, an OH value was used. 178 mgKOH / g (active hydrogen equivalent: 315) replaced by polyether polyol (polyol C), combined with isocyanate C,
A molded product was prepared and evaluated in the same manner as in Example 1 with a mixing ratio of 100: 124 (weight ratio) and an NCO index of 105. The results are shown in Table III.

Comparative Example 6 The same raw material as in Example 3 was used, and the mixing ratio was 100: 81.3.
(Weight ratio) A molded product was prepared and evaluated in the same manner as in Example 1 except that the NCO index was 90. The results are shown in Table III.

Comparative Example 7 The same raw materials as in Example 3 were used, and the mixing ratio was 100: 108.
(Weight ratio) A molded product was prepared and evaluated in the same manner as in Example 1 except that the NCO index was 120. Result III
It is shown in the table.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

[0061]

According to the present invention, a low-density semi-rigid polyurethane foam having excellent abrasion resistance can be released in a short time.
In the present invention, it is not necessary to use chlorofluorocarbon or chlorocarbon as the blowing agent.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C08L 75:04 (56) References JP-A-8-176251 (JP, A) JP-A-7-278332 (JP, A) JP-A-8-12794 (JP, A) JP-A-4-126732 (JP, A) JP-A-3-64312 (JP, A) JP-A-58-29837 (JP, A) (58) Int.Cl. ⁶ , DB name) C08G 18/00-18/87

Claims (3)

(57) [Claims] 1. A reaction injection molding method comprising the steps of: preparing a mixture of isocyanate and a polyol comprising a polyether-based polyol, a crosslinking agent, a catalyst, a foaming agent and, if necessary, an internal release agent, a reinforcing agent and other auxiliaries, by a reaction injection molding method. Density 0.3-0.3.
A method for producing a semi-rigid polyurethane foam having fine cells having a hardness of 9 g / cm < ³ > and a Shore A hardness of 40 to 90 degrees, wherein A) the isocyanate contains a trifunctional or higher polyisocyanate, and the trifunctional or higher polyisocyanate B) a polyether polyol having a content of 5% by weight or more of the entire isocyanate;
0 trifunctional polyether polyol having an active hydrogen equivalent of 0 and an ethylene oxide content of 5 to 30% by weight of the polyol, and an average active hydrogen equivalent of all polyether polyols of 500 to 12
Using a polyether polyol component having a viscosity of 200 to 800 mPas / 25 ° C., 2) to 20 parts by weight of 6) per 100 parts by weight of component B)
D) A process for producing a polyurethane foam, characterized by using a bifunctional crosslinking agent component having a molecular weight of 1 to 200, and D) molding a mixture of isocyanate and polyol with an NCO index of 100 to 115. 2. The isocyanate is diphenylmethane diisocyanate, polyphenylmethane polyisocyanate or a modified product thereof, the NCO% of which is 17 to 2
The method for producing a polyurethane foam according to claim 1, which is 9% by weight. 3. The isocyanate is a modified product of hexamethylene diisocyanate, at least a part of the modified product is a modified isocyanurate product, and has a viscosity of 200 to 120.
The method for producing a polyurethane foam according to claim 1, wherein the temperature is 0 mPas / 25 ° C.