JPH0940735A - Manufacturing method of rigid polyurethane foam - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To produce a rigid polyurethane foam having a low viscosity, excellent mixing property of a foaming liquid and excellent dimensional stability even when a hydrogen atom-containing halogenated hydrocarbon or water is used as a foaming agent. I will provide a. In a method for producing a rigid polyurethane foam by reacting a polyol and a polyisocyanate in the presence of a blowing agent, an alkylene oxide adduct of a compound having 2 or more active hydrogen as at least 5% by weight of the polyol. Hydroxyl group (-S
A compound obtained by substituting H) is used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a rigid urethane foam. More specifically, it relates to a method for producing a rigid urethane foam having excellent dimensional stability.

[0002]

2. Description of the Related Art Conventional rigid urethane foams have a trichloromonofluoromethane (CFC-11) as a blowing agent.
Since it is used, it has excellent dimensional stability and heat insulation properties, and is widely used as a heat insulating material for refrigerators, freezers, and construction. However, in recent years, to protect the ozone layer of the earth,
Regulations such as halogenated hydrocarbon blowing agents that do not contain hydrogen atoms have started. CFC-11 is included in this regulation target, and the foaming agent of rigid urethane foam is shifting to hydrogen element-containing halogenated hydrocarbon or water having a small ozone depletion potential. However, these newly used foaming agents have higher boiling points than CFC-11, so that the generated urethane resin is liable to aggregate and liquefy in the cell, and the internal pressure of the cell is lowered. Therefore, there is a problem that shrinkage easily occurs and dimensional stability is impaired.

As a method for improving dimensional stability, a method of using a polyfunctional polyether polyol having a high hydroxyl value has been proposed (for example, JP-A-7-109324).

[0004]

However, in the above method, the viscosity of the polyether polyol becomes too high,
There are problems such as poor mixing of the foaming liquid. The object of the present invention is to produce a rigid polyurethane foam using a hydrogen atom-containing halogenated hydrocarbon or water or a mixture thereof as a foaming agent, and to obtain a rigid polyurethane foam having a low viscosity and a good mixing property, and to use conventional CFC-11. It is an object of the present invention to provide a method for manufacturing a rigid polyurethane foam having equivalent dimensional stability.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have keenly studied a method for producing a rigid polyurethane foam having excellent dimensional stability by using a hydrogen atom-containing halogenated hydrocarbon or water or a mixture thereof as a blowing agent. As a result of repeated studies, by using an active hydrogen compound having a specific functional group as at least a part of the polyol component,
The inventors have found that the above problems can be solved and arrived at the present invention.

That is, in the present invention, a polyol (A) and a polyisocyanate (B) are reacted in the presence of a blowing agent (C) consisting of a hydrogen atom-containing halogenated hydrocarbon and / or water to give a rigid polyurethane foam. In the production method, at least 5% by weight of (A) is a compound (a) obtained by substituting a part of the hydroxyl groups of an alkylene oxide adduct of a compound having two or more active hydrogens with a hydrosulfur group (-SH). Is a method for producing a rigid urethane foam.

The compound (a) used in the present invention is obtained by adding an alkylene oxide to a compound having two or more active hydrogens, and substituting a part of the hydroxyl groups (one or more on average) with a hydrosulfur group (-SH). It is a compound obtained by Examples of the compound having two or more active hydrogens include alcohols, phenols, amines and polycarboxylic acids. Examples of alcohols include dihydric alcohols [ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and the like]; and trihydric or higher alcohols [glycerin ,
Trimethylolpropane, pentaerythritol, sorbitol, sucrose and the like]. Examples of the phenols include methylenebisphenol. As amines, ammonia; alkanolamines [mono-, di- or triethanolamine, isopropanolamine, aminoethylethanolamine, etc.]; alkylamines having 1 to 20 carbon atoms [monomethylamine, monoethylamine, etc.]; carbon Number 2 to 6 alkylenediamines [ethylenediamine, hexamethylenediamine, etc.]; polyalkylenepolyamines [diethylenetriamine, triethylenetetramine, etc.]; aromatic amines [aniline, phenylenediamine, diaminotoluene,
Xylylenediamine, methylenedianiline, diphenyletherdiamine, etc.]; alicyclic amines [isophoronediamine, cyclohexylenediamine, etc.]; and aminoethylpiperazine, heterocyclic amines described in JP-B-55-21044. . Examples of the polycarboxylic acids include aliphatic polycarboxylic acids [succinic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, etc.]; aromatic polycarboxylic acids [phthalic acid, terephthalic acid, trimellitic acid, etc.] and the like.

As the alkylene oxide to be added, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,4-
Alternatively, 2,3-butylene oxide, styrene oxide and a combination of two or more of these may be used. Of these, preferred is PO alone or a combination of EO and PO, and the addition form in the case of combination may be either block or random.

As a method for substituting a hydroxyl group with a hydrosulfur group (--SH), for example, the hydroxyl group is replaced with a chloro group with thionyl chloride, and further the chloro group is replaced with a hydrosulfur group (--SH) with sodium hydrosulfide. Known methods can be mentioned.

The polyol (A) in the present invention contains the above-mentioned (a) as an essential component.
Is usually at least 5% by weight, preferably at least 10% by weight, based on the weight of (A). The amount of (a) is 5
If it is less than wt%, the dimensional stability of the foam will be insufficient.

(A) is a known polyol (for example, a polyhydric alcohol or its alkylene oxide adduct, a polyester polyol, a polybutadiene polyol, an acrylic polyol, etc.) which is used together with (a) in an ordinary rigid polyurethane foam, if necessary. (Eg, a polymer polyol modified with a polymer of an ethylenically unsaturated monomer). Specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, pentaerythritol, methylglycolide, diglycerin, sorbitol and sucrose.

The average number of functional groups of (A) is usually 3 or more, preferably 3.3 or more, and the hydroxyl value is usually 150 or more, preferably 330 or more. When the average number of functional groups is less than 3 or the hydroxyl value is less than 150, the strength of the foam decreases and the foam tends to shrink.

As the polyisocyanate (B) used in the present invention, those conventionally used for rigid polyurethane foams can be used. Examples of such isocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified products thereof (for example, carbodiimide-modified, allophanate-modified, urea-modified, buret-modified, isosinurate-modified, oxazolidone-modified). , Isocyanate group-terminated prepolymers and mixtures of two or more thereof.

Specific examples of aromatic polyisocyanates include 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′- and 4,4 '
-Diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (crude MDI),
Examples thereof include naphthylene-1,5-diisocyanate, triphenylmethane-4,4 ′, 4 ″ -triisocyanate, xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate.
Specific examples of the aliphatic isocyanate include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate and xylylene diisocyanate. Specific examples of the alicyclic polyisocyanate include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate. Specific examples of the modified polyisocyanate include carbodiimide-modified MDI, sucrose-modified TDI, castor oil-modified MDI, and the like.
Preferred of these are MDI, crude MDI, sucrose modified TDI and carbodiimide modified MDI.

The ratio of the polyol (A) to the polyisocyanate (B) can be variously changed, but the equivalent ratio of the active hydrogen group of (A) to the isocyanate group of the polyisocyanate (B) is usually 1.0 :( 0.5 to 50), preferably 1.0: (0.9 to 30).

Specific examples of the hydrogen atom-containing halogenated hydrocarbon blowing agent used as the blowing agent (C) in the present invention include those of HCFC type (for example, HCFC-12).
3, HCFC-141b, HCFC-22 and HCF
C-142b); HFC type (for example, HFC-
134a, HFC-152a, HFC-356mff,
HFC-236ea, HFC-245ca, HFC-2
45fa and HFC-365mcf) and the like. HCFC-141 is preferable among these.
b, HFC-134a, HFC-356mff, HFC
-236ea, HFC-245ca, HFC-245f
a, HFC-365mcf and a mixture of two or more thereof. If necessary, water or a low boiling point hydrocarbon may be used in combination with these hydrogen atom-containing halogenated hydrocarbon blowing agents. Further, water may be used alone without using the above-mentioned halogenated hydrocarbon blowing agent or low boiling point hydrocarbon. Low boiling hydrocarbons usually have a boiling point of 0 to
It is a hydrocarbon at 50 ° C., and specific examples thereof include propane, butane, pentane and a mixture thereof. The amount of the hydrogen atom-containing halogenated hydrocarbon-based blowing agent used in the method of the present invention is usually 0 to 50 parts by weight, preferably 0 to 45 parts by weight, per 100 parts by weight of the polyol component. The amount of water used is usually 0 to 10 parts by weight, preferably 0.5 to 8 parts by weight, per 100 parts by weight of polyol. The amount of low boiling point hydrocarbons used is Polyol 1
It is usually 0 to 40 parts by weight, preferably 0, per 100 parts by weight.
~ 30 parts by weight.

In the present invention, if necessary, a catalyst usually used in a polyurethane reaction, for example, an amine catalyst (triethylenediamine, N-ethylmorpholine, diethylethanolamine, 1-isobutyl-2-methylimidazole, 1,8-diazabicyclo-) is used. [5,4,0] -undecene-7 etc.) and metal catalysts (stannous octylate, dibutyl stannate dilaurate, lead octylate etc.) can be used. The amount of the catalyst used is usually 0.001 to 5% by weight based on the weight of (A).

Further, if necessary, a foam stabilizer and a coloring agent (dye,
Known additives such as pigments), plasticizers, fillers, flame retardants, antioxidants and antioxidants can also be used.

An example of the method for producing the rigid polyurethane foam is as follows. First, the polyol component,
A predetermined amount of a foaming agent, a foam stabilizer, a catalyst and other additives are mixed. A polyurethane foamer or stirrer is then used to rapidly mix the mixture with the polyisocyanate component. The obtained mixture is poured into a mold. After curing, the mold is released to obtain a rigid polyurethane foam.

The rigid polyurethane foam obtained by the method of the present invention has high strength and good heat insulating property, and in particular has excellent dimensional stability, and therefore can be widely used as a heat insulating material for refrigerators, freezers, constructions and the like.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described below with reference to examples, but the present invention is not limited thereto.
In the following, "parts" and "%" are parts by weight and% by weight.
Is shown.

[0022]

【Example】

Production Example 1 182 g (1 mol) of sorbitol and 1.
PO 348g with 06g (0.019mol) as catalyst
(6 mol) was added and neutralized with 1.13 g (0.019 mol) of acetic acid, 1 g of pyridine was added as a catalyst, and 238 g (2 mol) of thionyl chloride was added dropwise at 80 ° C. to about 2 After reacting for a time, an average of 2 hydroxyl groups were replaced with chloro groups. Then, 156 g (2 mol) of sodium hydrosulfide dihydrate dissolved in 109 g of water was added dropwise at 70 ° C., and the reaction was carried out for about 1 hour to substitute the chloro group with a hydrosulfide group (—SH),
After liquid separation and removal of water, a small amount of magnesium sulfate was added to adsorb water, and the produced salt was filtered and removed to remove water, and the hydroxyl value was 399 and the sulfur group (-SH) content was 1
1.7% of polyol (a-1) was obtained.

Production Example 2 PO2 using 1.06 g (0.019 mol) of potassium hydroxide as a catalyst to 136 g (1 mol) of pentaerythritol.
32 g (4 mol) was added, and 1.13 g (0.01
(9 mol), 1 g of pyridine was added as a catalyst to the mixture, 119 g (1 mol) of thionyl chloride was added dropwise at 80 ° C., and the mixture was reacted for about 2 hours to replace one hydroxyl group with a chloro group on average. . Then, 78 g (1 mol) of sodium hydrosulfide dihydrate dissolved in 55 g of water was added dropwise at 70 ° C., and the reaction was carried out for about 1 hour to replace the chloro group with a hydrosulfide group (—SH),
After liquid separation to remove water, a small amount of magnesium sulfate was added to adsorb water, and the produced salt was filtered and removed to remove it, and the hydroxyl value 438 and the sulfur group (-SH) content were 8.
6% of polyol (a-2) was obtained.

Preparation Example 3 342 g (1 mol) of sucrose and 1.6 g of triethylamine
(0.016 mol) as a catalyst to which 464 g (8 mol) of PO was added, 1 g of pyridine was added as a catalyst, and 476 g (4 mol) of thionyl chloride was added dropwise at 80 ° C. and reacted for about 2 hours to give an average of 4 Each hydroxyl group was replaced with a chloro group. Then, 312 g (4 mol) of sodium hydrosulfide dihydrate dissolved in 218 g of water was added dropwise at 70 ° C. to about 1
After reacting for a period of time to replace the chloro group with a hydrosulfide group (-SH) and separating the water to remove water, a small amount of magnesium sulfate was added to adsorb water, and the water was filtered along with the generated salt to remove it. Hydroxyl value 246, Hydroxyl group (-SH) content 14.
5% of polyol (a-3) was obtained.

Production Example 4 232 g of PO (4 mol) was added to 60 g (1 mol) of ethylenediamine.
Mol) was added to 1 g of pyridine as a catalyst, and 238 g (2 mol) of thionyl chloride was added dropwise at 80 ° C. to react for about 2 hours, and an average of 2 hydroxyl groups was replaced with a chloro group. Then, 156 g (2 mol) of sodium hydrosulfide dihydrate dissolved in 109 g of water was added dropwise at 70 ° C., and the reaction was carried out for about 1 hour to substitute the chloro group with a hydrosulfide group (—SH),
After liquid separation and removal of water, a small amount of magnesium sulfate was added to adsorb water, and the salt thus formed was filtered and removed to remove water, and a hydroxyl value of 346 and a sulfur group (-SH) content of 2
0.4% of polyol (a-4) was obtained.

Example 1 To a mixture of 30 parts of polyol (a-1) and 70 parts of polyether polyol (1) having a hydroxyl value of 450 obtained by adding PO to a mixture of glycerin (1 mol) and sugar (0.5 mol). , "Silicone SH-193" (Toray Silicone, foam stabilizer) 1.5 parts, water 2 parts, "Phiroll C"
EF "(Flame retardant made by Akzo Japan, Inc.) 10 parts," DA
BCO NC-IM ”(manufactured by Sankyo Air Products Co., amine catalyst) 2.0 parts and“ HCFC-141b ”25.
Mix 9 parts in advance and adjust the temperature to 25 ° C.
After adding 159 parts of "Millionate MR-100" (manufactured by Nippon Polyurethane Co., Ltd., crude MDI) whose temperature was adjusted to ℃, the mixture was stirred at 3,000 rpm for 10 seconds at Homo Disper (stirrer manufactured by Tokushu Kiki Co., Ltd.), and then the temperature was adjusted to 25 ℃. ) ×
A 100 mm (width) × 100 (height) mm mold was poured into the end of the mold which was open in the direction perpendicular to the floor and was opposite to the opening of the mold, and the mold was removed after 10 minutes to obtain a rigid polyurethane foam.

Example 2 A mixture of 50 parts of polyol (a-2) and 50 parts of polyether polyol (1) was added with "Silicone SH-19.
3 "1.5 parts, water 2 parts," Phiroll CEF "10
Part, "DABCO NC-IM" 2.0 parts and "HC
FC-141b ”25.8 parts was pre-blended and temperature-controlled at 25 ° C., and 158 parts of“ Millionate MR-100 ”temperature-controlled at 25 ° C. was added thereto, and the same operation as in Example 1 was performed, A rigid polyurethane foam was obtained.

Example 3 A mixture of 10 parts of polyol (a-3) and 90 parts of polyether polyol (1) was added with "Silicone SH-19.
3 "1.5 parts, water 2 parts," Phiroll CEF "10
Part, "U-CAT1000" (manufactured by San-Apro Co., amine catalyst) 1.0 part and "HCFC-141b" 24.2
Parts are pre-blended and the temperature is adjusted to 25 ° C.
To 142 parts of "Millionate MR-100" whose temperature was adjusted was added to the above, and the same operation as in Example 1 was carried out to obtain a rigid polyurethane foam.

Example 4 20 parts of the polyol (a-4) and 80 parts of the polyether polyol (1) were mixed with 1.5 parts of "Silicone SH-193".
Part, water 2 parts, "Phiroll CEF" 10 parts, "UC
AT1000 "1.0 part and" HCFC-141b "
"Millionate MR-100" in which 25.3 parts was pre-blended and temperature-controlled at 25 ° C, and then temperature-controlled at 25 ° C therein
The same operation as in Example 1 was performed by adding 153 parts to obtain a rigid polyurethane foam.

Comparative Example 1 A mixture of 30 parts of a polyether polyol (2) having a hydroxyl value of 635 and 70 parts of a polyether polyol (1) obtained by adding PO (6 mol) to sorbitol (1 mol),
"Silicone SH-193" 1.5 parts, water 2 parts, "Phiroll CEF" 10 parts, "DABCO NC-IM"
2.0 parts and 25.5 parts of "HCFC-141b" were pre-blended and the temperature was adjusted to 25 [deg.] C., and 155 parts of "Millionate MR-100" whose temperature was adjusted to 25 [deg.] C. was added to the mixture of Example 1 and Example 1. The same operation was performed to obtain a rigid polyurethane foam.

Comparative Example 2 Polyether polyol (3) having a hydroxyl value of 610 obtained by adding PO (4 mol) to pentaerythritol (1 mol).
To a mixture of 50 parts and 50 parts of polyether polyol (1), "silicone SH-193" 1.5 parts, water 2
Part, "Phiroll CEF" 10 parts, "DABCON
C-IM "2.0 parts and" HCFC-141b "2
"Millionate MR-100" 1 in which 6.1 parts was preliminarily blended and the temperature was adjusted to 25 ° C, and the temperature was adjusted to 25 ° C therein 1
The same operation as in Example 1 was carried out by adding 61 parts to obtain a rigid polyurethane foam.

Comparative Example 3 100 parts of polyether polyol (1), 1.5 parts of "Silicone SH-193", 2 parts of water, and "Phiroll C"
EF "10 parts," U-CAT1000 "1.0 part and" HCFC-141b "24.1 parts were pre-blended to prepare 25
A rigid polyurethane foam was obtained by adjusting the temperature to ℃, and adding 141 parts of "Millionate MR-100" whose temperature was adjusted to 25 ℃ in the same manner as in Example 1.

Comparative Example 4 Polyether polyol (4) having a hydroxyl value of 374 obtained by adding PO (8 mol) to pentaerythritol (1 mol).
In 100 parts, 1.5 parts of "Silicone SH-193", 2 parts of water, 10 parts of "Phiroll CEF", "DABCO"
NC-IM "2.0 parts and" HCFC-141b "2
2.2 parts were pre-blended and the temperature was adjusted to 25 ° C, and the temperature was adjusted to 25 ° C in this "Millionate MR-100" 1
22 parts was added and the same operation as in Example 1 was performed to obtain a rigid polyurethane foam.

Test Example Viscosity was measured with a B-type viscometer. For evaluation of dimensional stability, 80 mm cubic foams were cut out, and the dimensions were measured 1 hour after molding and after standing for 3 weeks at 25 ° C., and the dimensional shrinkage ratio was calculated (average of length, width, height). The compressive strength was measured based on the JIS A9514 compressive strength test method (unit: kg / cm ² ). Table 1 shows the polyol viscosity, dimensional shrinkage and foam compressive strength measurement results of Examples 1 to 4, and Table 2 shows the polyol viscosity, dimensional shrinkage and foam compressive strength measurement results of Comparative Examples 1 to 4.

[0035]

[Table 1]

[0036]

[Table 2]

As is clear from Tables 1 and 2, the polyols of Examples 1 to 4 have the characteristics of giving rigid polyurethane foams having low viscosity and good dimensional stability.

[0038]

By using the rigid urethane foam manufacturing method of the present invention, even if a hydrogen atom-containing halogenated hydrocarbon or water is used as a foaming agent, it is equivalent to or more than the case of using conventional CFC-11. Dimensional stability of can be realized. The polyurethane foam obtained by the method of the present invention is extremely useful as a heat insulating material for refrigerators, freezers and building materials.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Kumagai 1-11, Hitotsubashi Honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd. (72) Inventor Tatsuro Yanagi 1-11, Hitotinomoto-cho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Within the corporation

Claims (2)

[Claims] 1. A polyol (A) and a polyisocyanate (B) are combined with a hydrogen atom-containing halogenated hydrocarbon and / or
Alternatively, in a method for producing a rigid polyurethane foam by reacting in the presence of a foaming agent (C) consisting of water,
At least 5% by weight of (A), a compound (a) obtained by substituting a part of hydroxyl groups of an alkylene oxide adduct of a compound having two or more active hydrogens with a hydrosulfide group (-SH).
A method for producing a rigid urethane foam, which comprises using 2. The molecular weight per functional group of (a) is 50 to 50.
The production method according to claim 1, which is 500.