JPH0386720A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain a polyurethane foam excellent in thermal conductivity, low temperature-dimensional stability and compressive strength by incorporating a specified blowing agent and a modified organic isocyanate in the starting material. CONSTITUTION:A process for producing a polyurethane foam from an organic polyisocyanate, a polyol, a blowing agent, a catalyst, a surfactant and other assistants, wherein 1,1-dichloro-1-fluoroethane is used as the blowing agent, and a modified organic isocyanate (e.g. trimer-modified product and/or carbodiimide-modified product) is used as the organic polyisocyanate. Although the foam prepared by using this blowing agent has been problematic in that, when compared with a foam prepared by using conventional trichlorofluoromethane, it has an increased thermal conductivity and remarkably deteriorated low temperature-dimensional stability and compressive strength, a foam having properties including dimensional change and compressive strength which are equivalent to those of a conventional foam can be obtained by using the modified organic isocyanate.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing polyurethane foam.

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

[Conventional technology]

Polyurethane foam has excellent heat insulating properties and low-temperature dimensional stability, so it is widely used as a heat insulating material for refrigerators, frozen warehouses, etc.

The main reason for this is that trichlorofluoromethane, which has excellent heat insulation properties, is used as a blowing agent when manufacturing polyurethane foam.

[Problem to be solved by the invention]

However, in recent years, regulations on chlorofluorocarbons have been considered in order to protect the earth's ozone layer, and are expected to be implemented in the near future.

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

Therefore, there is an urgent need to develop a blowing agent for polyurethane foam to replace trichlorofluoromethane, and 1,1-dichloro-1-fluoroethane is considered to be a candidate for the replacement in terms of various physical properties.

However, as a blowing agent, 1,1-dichloro-1-
When using fluoroethane, there are many problems compared to conventional foams foamed using trichlorofluoromethane, such as increased thermal conductivity, significant deterioration of low-temperature dimensional stability, and compressive strength. The present inventors have confirmed that a satisfactory foam cannot be obtained using the method for manufacturing urethane foam.

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

Furthermore, compared to the conventional method, the thermal insulation properties deteriorate and the cost increases, making it impossible to obtain a form that is practically satisfactory.

[Means for Solving the Problems] In order to overcome the above-mentioned problems, the present inventors have made intensive studies and found that 1.
We have discovered a method for producing polyurethane foam using 1-dichloro-l-fluoroethane without sacrificing the conventional excellent heat insulation properties and low-temperature dimensional stability.
We have arrived at the present invention.

That is, the present invention comprises organic polyisocyanates, polyols, blowing agents, catalysts, surfactants, and other auxiliary agents.
In the method for producing polyurethane foam, 1. Using L-dichloro-1-fluoroethane,
The present invention also relates to a method for producing polyurethane foam, characterized in that it uses a modified organic isocyanate.

Instead of the conventionally used trichlorofluoromethane,
], l-dichloro-1-fluoroethane, the method of the present invention produces for the first time a polyurethane foam with excellent thermal insulation properties, low-temperature dimensional stability, compressive strength, etc.

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

The modified organic isocyanate used in the present invention is one in which a part of the organic isocyanate below is converted into isocyanurate (trimer), carbodiimidized, urethanized, ureated, biuretated, or allophanated by a known method, Alternatively, most of the organic isocyanates listed below are prepared by performing the above reaction and then diluted with unreacted organic isocyanate, or are prepared by mixing two or more of the above modified products, and various conventionally used ones are available. A metamorphic body of is used.

Among the above-mentioned modified products, particularly preferred are trimer modified products and/or carbodiimide modified products.

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

The organic isocyanates used in the modified organic isocyanate of the present invention include conventionally known organic isocyanates and are not particularly limited. Isocyanate, crude diphenylmethane diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate,
Examples include xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, triphenylmethylene triisocyanate, and tolylene triisocyanate.

These modified organic isocyanates may be used alone or in combination of two or more. The amount used is such that the equivalent ratio of NCO groups to active hydrogen in the resin liquid is 0.8 to 5.0.

Examples of the polyols used in the present invention include ethylene glycol, propylene glycol, diethylene glycol,
Triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexanetriol, pentaerythritol, sorbitol, sucrose, bisphenol A1 novolac, hydroxylated 1,2-polybutadiene, hydroxylated 1
．． Hydroxyl number 200-800 obtained by addition polymerizing alkylene oxide to polyhydric alcohols such as 4-polybutadiene and/or these polyhydroxy compounds
A polyether polyol of mgKOH/g can be used.

In addition to the above, higher fatty acid ester polyols, polyester polyols obtained by reacting polycarboxylic acids with low molecular weight polyols, polyester polyols obtained by polymerizing caprolactone, higher fatty acid esters containing ○H groups such as castor oil, dehydrated castor oil, etc. can also be used.

As the blowing agent used in the present invention, 1.1-dichloro-1-fluoroethane may be used alone, or fluorocarbons such as trichlorofluoroethane and dichlorotrifluoroethane, or hydrocarbon compounds such as n-hexane may be used in combination. You can also do it.

Catalysts that can be used in the present invention include, for example, amine-based urethanization catalysts (triethylamine, tripropylamine,
Triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, jetanolamine, triethanolamine, N-methyl Jetanolamine, N, N-dimethylethanolamine, diethylenetriamine, N, N, N", No ~ Tetramethylethylenediamine, N, N, N', N'-tetramethylpropylenecyamine, N, NN', N' -tetramethylbutanediamine, N.

N,N',N'-tetramethyl-1,3-butanediamine, N,N,N",N"-tetramethylhexamethylenediamine, bis(2-(N,N-dimethylaξ])ethyl) Ether, N, N-dimethylbenzylamine, N
, N-dimethylcyclohexylamine, N, N, N'
N″,N″-penkmethyldiethylenetriazine, triethylenediamine, formate and other salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, N,N-dialkylpiperazines, etc. azacyclic compounds, various N,N',N"-trialkylaminoalkylhexahydrotriazines, β-aminocarbonyl catalyst of Japanese Patent Publication No. 52-43517, β-astra nonitrile catalyst of Japanese Patent Publication No. 53-14279, etc.), Organometallic urethanation catalysts (tin acetate, tin octylate, tin oleate, silver laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octoate, lead naphthenate, nickel naphthenate, cobalt naphthenate) etc.) etc.

These catalysts are used alone or in combination, and the amount used is o, oooi to 1 per 100 parts of the compound having active hydrogen.
It is 090 parts.

The foam stabilizer in the present invention is a conventionally known organosilicon surfactant, such as L-501 manufactured by Nippon Unicar Co., Ltd.
,, L-520, L-532, L-540, L-
544, L-3550, L-5302, L-5305
, L5320, L-5340, L-5410, L-54
20, L-5710゜L-5720, etc., and 5H-190, 5H-192,5 manufactured by Thoth Silicone Co., Ltd.
H-193, 5H-194, 5) I-195, 5H-2
00, 5RX-253, etc., and F-114, F-121, F-122, F-220, manufactured by Shin-Etsu Silicone Co., Ltd.
F-230, F-258, F-260B, F-3
05, F-306, F-31, 7, F-341, etc., and T F A-4200, T
FA-4202, etc.

The amount of these foam stabilizers used is 0.1 to 2 parts per 100 parts of the total of the compound with active hydrogen and the organic polyisocyanate.
It is 0 copies.

In addition, as a flame retardant, for example, tris(2-chloroethyl)
Phosphate, tris (dichloropropyl) phosphate, tris (dibromopropyl) phosphate, CR-505 and CR507 manufactured by Ohe Kagaku Co., Ltd., Fyrol 6 manufactured by Stoffer Chemical Co., etc. can be used.

Plasticizers, fillers, stabilizers, colorants, etc. can be added as necessary.

To carry out the present invention, predetermined amounts of a polyol, a catalyst, a blowing agent, a foam stabilizer, a flame retardant, and other auxiliary agents are mixed to form a resin liquid.

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

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

After injection, the polyurethane foam will expand and harden within a few minutes.

The polyurethane foam obtained by the present invention can be used in electric refrigerators,
1. It can be used as a heat insulating panel, a heat insulating material or a structural material for ships, vehicles, etc.

〔Example〕

The present invention will be specifically explained below with reference to Examples.

In the examples, the raw materials used are as follows. In addition, the part indicates the part where M is placed.

MDI-CR: Crude diphenylmethane diisocyanate manufactured by Mitsui Toatsu Chemical Co., Ltd. NC0% 31. O it isocyanate A: A carbodiimide modified product of diphenylmethane diisocyanate, which is a mixture of NCO group-containing ff128.3% and crude diphenylmethane diisocyanate (NCO group-containing i30.0%) at a ratio of 50:50 parts by weight.lICO group content 29.2 % isocyanate.

Modified isocyanate B: NC is a trimer modified product of tolylene diisocyanate, which is a mixture of NCO group-containing ff130.5% and crude diphenylmethane diisocyanate (NCO group content: 30%) at a ratio of 50:50 parts by weight.
Isocyanate with 130.3% Ol content.

Polyol A: polyether polyol with a hydroxyl value of 400 mgKOH/g, obtained by adding propylene oxide to monosaccharide/glycerinPolyol Bi) Polyether polyol with a hydroxyl value of 400 KOH/g, which is obtained by adding propylene oxide to lylene diamine/triethanolamine .

L-5420 manufactured by Nippon Unicar@ Minjc made by Active Wood Career @.

TMHD (Tetramethylhexamethylenecyan) Foam stabilizer; Catalyst; Foaming agent F-141b; Mitsui DuPont Fluorochemical ■
1,1-dichloro-1-fluoroethane manufactured by Co., Ltd. F-14
1b F-11; Trichlorofluoromethane F-11 (trade name) manufactured by Mitsui DuPont Fluorochemicals 01 Examples 1 to 5 and Comparative Examples 1 to 4 A resin solution having the formulation shown in Table 1 was prepared, and this was crudely used as an isocyanate. diphenylmethane diisocyanate and were rapidly mixed for 8 seconds at 5,000 rpm, and the size was 20.
The mixture was immediately poured into a vertical wooden box of 0x200x200 am and allowed to foam freely.

It foams and hardens within a few minutes after injection, yielding polyurethane foam.

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

In addition, the mixed liquid was injected into a vertical porosity with dimensions of 300 x 300 x thickness of 35 mm and foamed, and after one day of foaming, the size was 20 mm.
The thermal conductivity was measured by cutting out 0 x 200 x 25111 m.

〔Effect of the invention〕

From Table 1, in the conventional manufacturing method (comparative example), when 1,1-dichloro-14 fluoroethane was used as the blowing agent (comparative examples 2 and 4), when trichlorofluoromethane was used (comparative example 1), and 3), the thermal conductivity, dimensional change rate, and compressive strength are inferior.

However, in Examples 1 to 5 according to the method of the present invention, those using conventional trichlorofluoromethane (Comparative Examples 1 and 3)
) was obtained with physical properties such as dimensional change rate and compressive strength equivalent to those of

Claims (1)

[Claims] 1. A method for producing polyurethane foam from an organic polyisocyanate, a polyol, a blowing agent, a catalyst, a surfactant and other auxiliaries, in which 1,1-
A method for producing polyurethane foam, characterized in that dichloro-1-fluoroethane is used and a modified organic isocyanate is used as the organic polyisocyanate. 2. The method for producing polyurethane foam according to claim 1, wherein the modified organic isocyanate is a trimer modified product and/or a carbodiimide modified product.