JP2845972B2 - How to make insulation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a heat insulating material made of a rigid polyurethane foam.

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

[Conventional technology]

Rigid polyurethane foams are widely used as heat insulating materials for refrigerators, freezer warehouses, etc. because of their excellent heat insulating properties and low-temperature dimensional stability.

This is largely due to the use of trichlorofluoromethane having excellent heat insulating properties as a foaming agent when producing a rigid polyurethane foam.

[Problems to be solved by the invention]

In recent years, regulation of chlorofluorocarbons has been considered to protect the ozone layer of the earth, and is going to be implemented in the near future.

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

Therefore, there is an urgent need to develop a foaming agent for rigid polyurethane foam, which replaces trichlorofluoromethane. In view of various physical properties, 1,1-dichloro-1-fluoroethane is considered as a candidate for an alternative.

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, etc., as compared with a foam foamed using conventional trichlorofluoromethane. The present inventors have confirmed that a satisfactory foam cannot be obtained by the method for producing a rigid urethane foam.

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, a practically satisfactory foam has not been obtained since the heat insulating properties have been deteriorated and the cost has been increased.

[Means for solving the problem]

The present inventors have conducted intensive studies in order to overcome the above problems, and as a result, as a foaming agent for rigid polyurethane foam, 1,1-dichloro-1-fluoroethane was used instead of the conventionally used trichlorofluoromethane. Even when used, a method for producing a heat insulating material comprising a rigid polyurethane foam without impairing the 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 rigid 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. The polyol is a polyester polyol
The present invention relates to a method for producing a heat insulating material comprising a rigid polyurethane foam, characterized in that the heat insulating material contains -60% by weight.

According to the method of the present invention, for the first time, a heat insulating material made of a rigid polyurethane foam having excellent heat insulating properties, low-temperature dimensional stability, and compressive strength is produced.

The polyester polyol used in the present invention is obtained by an esterification reaction by opening a polyester polyol composed of an aliphatic polybasic acid and a polyhydric alcohol, an alkyl ester of an aromatic polybasic acid or an anhydride thereof, and caprolactone. Compounds and the like can be used.

Examples of the polyester polyol comprising an aliphatic polybasic acid and a polyhydric alcohol include stearic acid ethyl ester, polyethylene adipate ester, polybutylene adipate ester and the like, and an aromatic cyclic polybasic acid or an alkyl ester of an anhydride thereof, Examples include ethyl benzoate, dimethyl terephthalate, dimethyl isophthalate, and the like.

Further, as a compound obtained by subjecting caprolactone to ring-opening and esterification, for example, JP-A-57-1641
21.A compound synthesized by the method described in 21, for example, such as Praxel 303, Praxel 3
It is marketed under the trade name of 05 (manufactured by Daicel Chemical Industries, Ltd.).

One or a mixture of two or more of these polyester polyols is added to 100 parts by weight of the following polyol, and
By using up to 60 parts by weight, even when 1,1-dichloro-1-fluoroethane is used, the delay in the initial reactivity is eliminated, and low-temperature dimensional stability and excellent foam properties such as compressive strength are obtained. A rigid polyurethane foam is produced.

When the amount of the polyester polyol is 1 part by weight or less based on 100 parts by weight of the total polyol, the physical properties of the foam such as thermal conductivity, low-temperature dimensional stability, and compressive strength are deteriorated, and the effect of addition is extremely small.

On the other hand, when the amount of the polyester polyol is 60 parts by weight or more, the foam becomes brittle and is not suitable for producing a rigid polyurethane foam.

Polyols that can be used in combination in the present invention include, for example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexanetriol, pentaerythritol, sorbitol, shoe cloth, 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 polymerization of alkylene oxide to these polyhydroxy compounds. Alkanolamines such as diethanolamine and triethanolamine;
Compounds containing two or more active hydrogens such as ethylenediamine, diethylenetriamine, ammonia, aniline, tolylenediamine, xylylenediamine, diaminodiphenylmethane and / or these amines, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. Can be used. Polyether polyol and polytetramethylene ether glycol having a hydroxyl value of 200 to 800 mgKOH / g obtained by addition polymerization of

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

The organic polyisocyanate used in the present invention is a conventionally known organic polyisocyanate, and is not particularly limited.
Aliphatic and alicyclic polyisocyanates and modified products thereof, for example, diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone Diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, triphenylmethylene triisocyanate, tolylene triisocyanate, modified (carbodidiimide etc.) diphenylmethane diisocyanate and the like, and mixtures thereof. NCO-terminated prepolymers (NCO-containing, for example, 5-35%) obtained by reacting an excess amount of polyisocyanate with a polyol (for example, a low-molecular-weight polyol / or a polymer polyol), and the like. That.

These isocyanates are used alone or in combination of two or more. 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.

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, formate and other salts of triethylenediamine, primary and secondary Oxyalkylene adducts of amino groups of amines, azacyclic compounds such as N, N-dialkylpiperazines, various N, N ', N "-
Trialkylaminoalkyl hexahydrotriazines (β-aminocarbonyl catalyst of JP-B-52-43517,
Β-aminonitrile catalyst of JP-B-53-14279, etc., organometallic urethanization catalysts (tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, octane) Lead acid, lead naphthenate, nickel naphthenate, cobalt naphthenate, etc.).

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 organosilicon 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-260, B, 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 or the like 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 obtained rigid polyurethane foam stock solution is injected into a void or a mold. At this time, the flow rate ratio between the resin solution and the 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 rigid polyurethane foam foam-hardens within a few minutes.

The rigid polyurethane foam obtained in 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; Mitsui Toatsu Chemical Co., Ltd. crude diphenylmethane diisocyanate NCO% 31.0 Polyol A; Polyether polyol polyol B having a hydroxyl value of 400 mg KOH / g obtained by adding propylene oxide to sucrose / glycerin; B; propylene oxide to sorbitol / glycerin Polyether polyol having an added hydroxyl value of 400 mgKOH / g. Praxel-303; a polyester polyol manufactured by Daicel Chemical Industries, Ltd., which is a ring-opening polymer of ε-caprolactone.
Hydroxyl value 540mgKOH / g, molecular weight 300.

HIT-15; a polyester polyol synthesized from a cyclic dicarboxylic acid and diethylene glycol, manufactured by Active Materials Chemical Co., Ltd., having a hydroxyl value of 440 mgKOH / g.

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

Foam hardens within a few minutes after injection, resulting in a rigid polyurethane foam.

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

[Effects of the Invention] From Table 1, it can be seen that in the conventional production method, 1,1
In the case of using -dichloro-1-fluoroethane (Comparative Examples 2 and 4), the dimensional change rate and the compressive strength were inferior to those in the case of using trichlorofluoromethane (Comparative Examples 1 and 3).

When the amount of the polyester polyol of the present invention was too large (Comparative Example 5), the reactivity was too fast, and a satisfactory foam could not be obtained.

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.

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Claims (1)

(57) [Claims] 1. A method for producing a heat insulating material comprising a rigid polyurethane foam obtained by reacting an organic polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and other auxiliaries, wherein the foaming agent is 1,1. 1-dichloro-1
Using fluoroethane and the polyol is 30% by weight of a polyester polyol composed of an aliphatic polybasic acid and a polyhydric alcohol and / or a polyester polyol composed of an aromatic polybasic acid or an anhydride thereof and a polyhydric alcohol; A method for producing a heat insulating material comprising a rigid polyurethane foam, wherein the heat insulating material contains more than 60% by weight or less.