JP2887206B2 - Manufacturing method of polyurethane foam - Google Patents

Description

The present invention relates to a method for producing a polyurethane foam.

More specifically, the present invention relates to a method for producing a polyurethane foam having excellent thermal conductivity, low-temperature dimensional stability and compressive strength by using 1,1-dichloro-1-fluoroethane as a foaming agent.

[Conventional technology]

Polyurethane foam has excellent heat insulation properties and low-temperature dimensional stability.
Widely used.

This is largely because trichlorofluoromethane having excellent heat insulating properties is used as a foaming agent when producing a polyurethane foam.

[Problems to be solved by the invention]

However, in recent years, regulations for chlorofluorocarbons have been considered for the protection of the ozone layer on the earth, and will be implemented in the near future.

This regulation also includes trichlorofluoromethane, which has been used as a foaming agent for polyurethane foams.

Therefore, it is urgent to develop a foaming agent for polyurethane foam instead of trichlorofluoromethane, and 1,1-dichloro-1-fluoroethane is considered as a candidate for a substitute in view of various physical properties.

However, as a blowing agent, 1,1-dichloro-1-
When fluoroethane is used, there are many problems such as an increase in thermal conductivity, a low-temperature dimensional stability, and a remarkable deterioration in compressive strength as compared with a foam foamed using conventional trichlorofluoromethane. The present inventors have confirmed that a satisfactory foam cannot be obtained by the urethane foam production method.

Therefore, when 1,1-dichloro-1-fluoroethane is used, it is necessary to considerably increase the density in order to have the same low-temperature dimensional stability and foam properties such as compressive strength.

Furthermore, practically satisfactory foams cannot be obtained, for example, the heat insulating properties are deteriorated and the cost is increased as compared with the prior art.

[Means for solving the problem]

The present inventors have conducted intensive studies to overcome the above-mentioned problems, and as a result, as a foaming agent for polyurethane foam, instead of trichlorofluoromethane conventionally used, 1,1,
Even when 1-dichloro-1-fluoroethane is used, a method for producing a polyurethane foam without impairing conventional excellent heat insulating properties and low-temperature dimensional stability has been found, and the present invention has been achieved.

That is, the present invention provides a method for producing a polyurethane foam from an organic polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and other auxiliaries, using 1,1-dichloro-1-fluoroethane as a foaming agent. And a process for producing a polyurethane foam, characterized by using a modified organic isocyanate.

When 1,1-dichloro-1-fluoroethane is used in place of the conventionally used trichlorofluoromethane, the method of the present invention provides a polyurethane having, for the first time, excellent heat insulating properties, low-temperature dimensional stability, and compressive strength. A foam is manufactured.

In the method of the present invention, by using a modified organic isocyanate, even when 1,1-dichloro-1-fluoroethane is used as a foaming agent, heat conductivity, low-temperature dimensional stability, compressive strength, etc. A polyurethane foam having excellent foam properties is produced.

The modified organic isocyanate used in the present invention,
A part of the following organic isocyanates were subjected to isocyanurate (trimer), carbodiimidation, urethanization, ureaization, biuretation, or allophanate formation by a known method, or most of the following organic isocyanates were subjected to the above reaction. It is prepared by diluting with an unreacted organic isocyanate, or a mixture of two or more of the above-mentioned modified products, and various conventionally used modified products are used.

Among the above-mentioned modifications, particularly preferred are the trimer modification and / or the carbodiimide modification.

The above-mentioned modified isomer of the organic isocyanate can be produced by the method described in, for example, JP-A-59-166537, and the modified carbodiimide can be produced by the method described in, for example, JP-B-48-22694.

The organic isocyanate used in the modified form of the organic isocyanate of the present invention is conventionally known, and is not particularly limited, and may be aromatic, aliphatic, or alicyclic polyisocyanate and a modified product thereof such as diphenylmethane diisocyanate. Isocyanate, crude diphenylmethane diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, Triphenylmethylene triisocyanate,
Tolylene triisocyanate and the like can be mentioned.

These modified organic isocyanates may be used alone or
Mix and use more than one species. The amount of use is such that the equivalent ratio between the NCO group and the active hydrogen in the resin solution is 0.8 to 5.0.

The polyol used in the present invention is, for example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexanetriol, pentaerythritol, sorbitol, sucrose, bisphenol A , Novolak, hydroxylated 1,2-polybutadiene, hydroxylated 1,4
-Polyhydric alcohols such as polybutadiene and / or polyether polyols having a hydroxyl value of 200 to 800 mgKOH / g obtained by addition-polymerizing an alkylene oxide to these polyhydroxy compounds can be used.

Besides the above, polyester polyols obtained by reacting higher fatty acid ester polyols and polycarboxylic acids with low molecular weight polyols and polyester polyols obtained by polymerizing caprolactone, castor oil, and OH group-containing higher fatty acid esters such as dehydrated castor oil are also included. Can be used.

As the blowing agent used in the present invention, 1,1-dichloro-1-fluoroethane alone or in combination with a fluorocarbon such as trichlorofluoroethane and dichlorotrifluoroethane or a hydrocarbon compound such as n-hexane is used. Can also.

Examples of the catalyst that can be used in the present invention include amine urethanization catalysts (triethylamine, tripropylamine, triisopropanolamine, tributylamine,
Trioctylamine, hexadecyldimethylamine, N
-Methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, diethylenetriamine, N, N, N ', N'-tetra Methylethylenediamine, N, N, N ', N'-tetramethylpropylenediamine, N, N, N', N'-tetramethylbutanediamine,
N, N, N ', N'-tetramethyl-1,3-butanediamine, N,
N, N ', N'-tetramethylhexamethylenediamine, bis [2- (N, N-dimethylamino) ethyl] ether,
N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N, N ', N ", N" -pentamethyldiethylenetriamine, triethylenediamine, triethylenediamine formate and other salts, primary and secondary Oxyalkylene adducts of amino groups of diamines, azacyclic compounds such as N, N-dialkylpiperazines, various N, N ', N "-
Trialkylaminoalkylhexahydrotriazines, β-aminocarbonyl catalyst of JP-B-52-43517, β-aminonitrile catalyst of JP-B-53-14279, etc., organometallic urethanization catalysts (tin acetate, tin octylate, olein) Tin acid, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octanoate, lead naphthenate, nickel naphthenate, cobalt naphthenate and the like.

These catalysts are used alone or as a mixture, and the amount of use is 0.0001 to 10.0 parts with respect to 100 parts of the compound having active hydrogen.

The foam stabilizer in the present invention is a conventionally known organic silicon coarse surfactant, for example, L-50 manufactured by Nippon Unicar Co., Ltd.
1, L-520, L-532, L-540, L-544, L-3550,
L-5302, L-5305, L-5320, L-5340, L-5410,
L-5420, L-5710, L-5720, etc., and SH-190, SH-192, SH-193, SH-194, manufactured by Toray Silicone Co., Ltd.
SH-195, SH-200, SRX-253, etc., and Shin-Etsu Silicone F-114, F-121, F-122, F-220, F-23
0, F-258, F-260B, F-305, F-306, F-317,
F-341 etc., manufactured by Toshiba Silicone TFA-420
0, TFA-4202 and the like.

The amount of the foam stabilizer used is 0.1 to 20 parts based on 100 parts of the total of the compound having active hydrogen and the organic polyisocyanate.

Examples of the flame retardant include tris (2-chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (dibromopropyl) phosphate, CR-505 and CR-507 manufactured by Daihachi Chemical Co., and Stoffer Chemical Co., Ltd.
Fyrol.6 etc. can be used.

In addition, a plasticizer, a filler, a stabilizer, a colorant, and the like can be added as needed.

To carry out the present invention, a polyol, a catalyst, a blowing agent,
A predetermined amount of a foam stabilizer, a flame retardant and other auxiliaries are mixed to form a resin solution.

Using a polyurethane foaming machine, the resin solution and the polyisocyanate are rapidly mixed continuously at a constant ratio.

The resulting polyurethane foam stock solution is injected into a cavity or a mold. At this time, the flow rate ratio between the resin liquid and the organic polyisocyanate is adjusted so that the equivalent ratio between the organic polyisocyanate and the active hydrogen-containing compound becomes 0.8 to 5.0.

After injection, the polyurethane foam foams and hardens within a few minutes.

The polyurethane foam obtained by the present invention can be used as a heat insulating material or a structural material for electric refrigerators, heat insulating panels, ships or vehicles, and the like.

〔Example〕

 Hereinafter, the present invention will be described specifically with reference to examples.

In the examples, the raw materials used are as follows. Parts represent parts by weight.

MDI-CR; crude diphenylmethane diisocyanate NCO% 31.0 manufactured by Mitsui Toatsu Chemicals, Inc. Modified isocyanate A; carbodiimide modified diphenylmethane diisocyanate having an NCO group content of 28.3%
%) In a ratio of 50:50 parts by weight, isocyanate having an NCO group content of 29.2%.

Modified isocyanate B: a trimer modified tolylene diisocyanate having an NCO group content of 30.5% and a crude diphenylmethane diisocyanate (NCO group content of 30.0%) mixed at a ratio of 50:50 parts by weight of isocyanate having an NCO group content of 30.3% .

Polyol A; a polyether polyol having a hydroxyl value of 400 mg KOH / g obtained by adding propylene oxide to sucrose / glycerin Polyol B: a polyether polyol having a hydroxyl value of 400 mg KOH / g obtained by adding propylene oxide to tolylenediamine / triethanolamine.

L-5420 catalyst manufactured by Nippon Unicar Co., Ltd .; Minico TMHD (tetramethylhexamethylenediamine) manufactured by Active Materials Chemical Co., Ltd. Foaming agent F-141b; 1,1 manufactured by Mitsui DuPont Fluorochemicals Co., Ltd. 1−
Dichloro-1-fluoroethane. F-141b F-11; Trichlorofluoromethane F-11 (trade name) manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd. Examples 1 to 5 and Comparative Examples 1 to 4 A resin solution having the composition shown in Table 1 was prepared. Was rapidly mixed with crude diphenylmethane diisocyanate at 5000 rpm for 8 seconds to obtain a size of 200 × 200.
Immediately poured into a vertical wooden box of 200 mm and freely foamed.

A few minutes after the injection, the foam is cured and a polyurethane foam is obtained.

The resulting polyurethane foam was measured for low-temperature dimensional stability, that is, the dimensional change rate when left at −30 ° C. for 24 hours, and compressive strength.

In addition, the mixed solution was injected into a vertical porosity of dimensions 300 × 300 × thickness 35 mm and foamed. One day after foaming, the thermal conductivity was measured by cutting out dimensions 200 × 200 × 25 mm.

[Effects of the Invention] From Table 1, when 1,1-dichloro-1-fluoroethane is used as the blowing agent in the conventional production method (Comparative Example) (Comparative Examples 2 and 4), trichlorofluoromethane is used. The thermal conductivity, the dimensional change rate, and the compressive strength are inferior to those in the case of (Comparative Examples 1 and 3).

However, in Examples 1 to 5 according to the method of the present invention, dimensional changes equivalent to those using conventional trichlorofluoromethane (Comparative Examples 1 and 3) and physical properties with compressive strength were obtained.

Continuation of the front page (56) References JP-A-3-128915 (JP, A) JP-A-1-225612 (JP, A) JP-A-1-225611 (JP, A) JP-A-1-225614 (JP) JP-A-1-234432 (JP, A) JP-A-2-123119 (JP, A) JP-A-3-9933 (JP, A) JP-A-3-86718 (JP, A)

Claims (1)

(57) [Claims] 1. A method for producing a polyurethane foam from an organic polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and other auxiliaries, wherein the method comprises the steps of:
A process for producing a polyurethane foam, comprising using 1,1-dichloro-1-fluoroethane, and using a modified trimer and a modified carbodiimide of an organic isocyanate as an organic polyisocyanate.