JPH09302130A - Foamed heat-insulation material and heat-insulation box filled with the foamed heat-insulation material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject heat-insulation material containing fine bubbles, having low thermal conductivity and excellent heat-insulation performance and useful for refrigerator, etc., by adding a hydrofluorocarbon to a component composed of cyclopentane and water. SOLUTION: A mixture produced by mixing and stirring an isocyanate, a polyol, a blowing agent, a reaction catalyst and a foam stabilizer is foamed by the action of the foaming agent composed of (A) a 1st component consisting of (i) cyclopentane and (ii) water and (B) a 2nd component composed of at least one kind of hydrofluorocarbon having a boiling point of <=20 deg.C at normal temperature. The amount of the component (ii) is <=1.5 pts.wt. based on 100 pts.wt. of the polyol component. Preferably, the component B is 1,1,1,2- tetrafluoroethane, etc., and the amount of the component B is 0.1-5 pts.wt. based on 100 pts.wt. of the polyol component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam insulation material that can be used in refrigerators, freezers and the like, and a heat insulation box body filled with the foam insulation material.

[0002]

2. Description of the Related Art In recent years, chlorofluorocarbons (hereinafter, referred to as chlorofluorocarbons)
Environmental problems such as ozone layer depletion and global warming due to the effects of "CFC") and hydrochlorofluorocarbons (hereinafter referred to as "HCFC") are drawing attention. When manufacturing rigid urethane foam used as a foam insulation material for refrigerators, freezers, etc., CFC,
In order to reduce the amount of HCFC used, carbon dioxide generated by the reaction of organic polyisocyanate with water is used as a part of the blowing agent, and as a substitute for CFC and HCFC, it does not destroy the ozone layer and A method of using cyclopentane, which has little influence on the environment, as a foaming agent has been studied.

Conventionally, a rigid urethane foam which is a foamed heat insulating material has been produced by mixing and stirring an organic polyisocyanate and a polyol component in which a foaming agent, a foam stabilizer and a catalyst have been mixed in advance. At that time, as the foaming agent, trichlorofluoromethane (CF) is used because the thermal conductivity of the gas is extremely small and the boiling point is near room temperature.
C-11) and 1,1-dichloro-1-fluoroethane (HCFC-141b) have been used.

On the other hand, since cyclopentane has a higher gas thermal conductivity than CFC-11 or HCFC-141b, the thermal conductivity of the rigid urethane foam using this as a foaming agent is high, and the heat insulation is high. Performance decreases. Therefore, for example, when a rigid urethane foam using such a gas having a high thermal conductivity as a foaming agent is used for the foam insulation material of a heat insulation wall of a refrigerator having a conventional structure, heat leakage from the heat insulation wall becomes large. There is a problem that the power consumption of the refrigerator increases.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to use cyclopentane, which has little influence on the global environment, as a main component of a blowing agent. It is an object of the present invention to provide a foamed heat insulating material having excellent heat insulating properties and a heat insulating box body filled with the foamed heat insulating material.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an isocyanate, a polyol, a specific foaming agent, a reaction catalyst, and a foam stabilizer which have little influence on the global environment. The inventors have found that a foamed heat insulating material having excellent heat insulating properties can be obtained by mixing and stirring to obtain a mixture and foaming the mixture, thus completing the present invention.

That is, the present invention provides a foamed heat insulating material obtained by mixing and stirring an isocyanate, a polyol, a foaming agent, a reaction catalyst, and a foam stabilizer to obtain a mixture, and foaming the mixture. The foaming agent comprises a first component composed of cyclopentane and water, and a second component composed of at least one kind of hydrofluorocarbon having a boiling point of 20 ° C. or lower at room temperature, and the amount of water used is the polyol component. 10
The present invention relates to a foamed heat insulating material which is 1.5 parts by weight or less with respect to 0 parts by weight.

In the present invention, the hydrofluorocarbon is 1,1,1,2-tetrafluoroethane (HF).
C-134a), 1,1-difluoroethane (HFC-
152a), 1,1,1,2,2-pentafluoroethane (HFC-125), difluoromethane (HFC-3)
2) and 1,1,1-trifluoroethane (HFC-
143a) to at least one foam insulation material.

Further, the hydrofluorocarbon is
HFC-134a, HFC-152a, HFC-12
5, at least one selected from the group consisting of HFC-32 and HFC-143a, the amount of the hydrofluorocarbon used is in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the polyol. It is preferable.

In the present invention, the hydrofluorocarbon is 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3,3-hexafluoropropane (HFC- 236ea) and 1,1,2-trifluoroethane (HFC-143).

Further, the hydrofluorocarbon is
HFC-245fa, HFC-236ea and HFC
When it is at least one selected from the group consisting of -143, the amount of the hydrofluorocarbon used is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyol.

Further, the present invention relates to a heat insulating box body comprising an outer box, an inner box, and any one of the foamed heat insulating materials filled in a gap formed between the outer box and the inner box.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The characteristic feature of the rigid urethane foam which is the foam insulation material of the present invention lies in the composition of the foaming agent used. This foaming agent is used by combining a first component and a second component, the first component is composed of cyclopentane and water, and the second component is a hydrofluorocarbon (boiling point under atmospheric pressure of less than 20 ° C.). Hereinafter, referred to as "HFC"). The amount of water used is 1 part by weight based on 100 parts by weight of the polyol.

Cyclopentane is decomposed into a substance that does not adversely affect the ozone layer by the time it reaches the ozone layer even when it is released into the atmosphere, and the boiling point of CFC-11 is the conventional blowing agent.
And close to HCFC-141b. Therefore, from the viewpoint of protecting the global environment, it is desirable as a foaming agent to replace the CFC and HCFC.

However, since cyclopentane has a higher gas thermal conductivity than CFCs and HCFCs, a conventionally known hard urethane foam using a blowing agent containing cyclopentane as a main component has a high thermal conductivity. I had a flaw.

The present inventors have conducted various studies to reduce the thermal conductivity of a rigid urethane foam using cyclopentane and water as a blowing agent, and as a result, added cyclopentane and water as a blowing agent. By using a specific HFC, the thermal conductivity of the obtained rigid urethane foam can be reduced, and by lowering the amount of water used to a specific amount, the low thermal conductivity aimed at by the present invention can be achieved. It has been found that a rigid urethane foam having can be obtained. It is not clear why the thermal conductivity of the rigid urethane foam can be lowered by doing so, but by using a specific HFC additionally, the bubbles of the urethane foam can be made finer, and further, in the generation of bubbles. Although it is indispensable, carbon dioxide gas with a large thermal conductivity is generated by the reaction with isocyanate, and as a result, the amount of water used that increases the thermal conductivity of the entire rigid urethane foam can be suppressed to a specific amount. I think this is because of the reason.

As the specific HFC, it is necessary to use an HFC having a boiling point of 20 ° C. or lower at normal pressure, and it is preferable to use an HFC having a boiling point within the range of −55 to 15 ° C. at normal pressure. When HFC having a boiling point of more than 20 ° C. is used, a mixture obtained by mixing and stirring an isocyanate, a polyol, a foaming agent, a reaction catalyst and a foam stabilizer is immediately discharged from the high pressure urethane foaming machine at room temperature and becomes floss-like. Does not foam. That is, since HFC cannot contribute to the generation of bubbles in the foaming process, the bubbles of the obtained urethane foam cannot be sufficiently miniaturized. Further, when HFC having a boiling point of more than 15 ° C. is used, the mixture may not be foamed sufficiently in a floss immediately after being discharged, although it depends on the foaming conditions and the like. There is a possibility that you will not be able to get enough. On the other hand, the boiling point is −
If HFC lower than 55 ° C. is used, the mixture may be foamed violently in a frothy state immediately after being discharged, and voids may be generated in the obtained hard urethane foam, resulting in a decrease in thermal conductivity. There is.

Of these HFCs, preferred HFCs
As HFC-134a, HFC-152a, HF
C-125, HFC-32, HFC-143a, HFC
-245fa, HFC-236ea or HFC-14
3, HFCs are preferable as the second component of the foaming agent used in the present invention because of their low gas thermal conductivity and good meltability in polyol.

HFC-134a is one of the tetrafluoroethane isomers, has a boiling point in a preferable range, has a low gas thermal conductivity, has a good meltability in a polyol, and is easy to produce. It is superior to the other isomers of tetrafluoroethane as the second component of the blowing agent used in the present invention. Further, HFC-152a is one of the isomers of difluoroethane, and the second component of the blowing agent used in the present invention as compared with the other isomers of difluoroethane is the same as the above-described preferable reason for HFC-134a. Is excellent. HFC-125 is one of the isomers of petanefluoroethane, and the blowing agent used in the present invention compared to other isomers of pentafluoroethane for the same reason as described above for HFC-134a. It is excellent as the second component of. In addition, HFC-32 is HFC-13
4a is excellent as the second component of the foaming agent used in the present invention for the same reason as the above-mentioned preferable reason. In addition, HFC-1
43a and HFC-143 are one of the isomers of trifluoroethane, and are used in the present invention in comparison with other isomers of trifluoroethane because of their low gas thermal conductivity and good solubility in polyol. Excellent as the second component of the foaming agent. Further, HFC-245fa is one of the isomers of pentafluoropropane, has a boiling point in a preferable range, has a low gas thermal conductivity, has a good solubility in a polyol, and is good in utilizing conventional foaming equipment. It is excellent as the second component of the foaming agent used in the present invention in comparison with other isomers of pentafluoropropane in that it can produce a rigid urethane foam. HFC-236ea is one of the hexafluoropropane isomers, and HFC-236ea
For the same reason as the above-mentioned preferable reason for 245fa, it is superior to the other isomers of hexafluoropropane as the second component of the blowing agent used in the present invention.

The suitable amount of these HFCs to be used depends on the type of HFC, and is HFC-134a and HFC-152.
a, HFC-125, HFC-32 and HFC143
In the case of a, 0.1 to 5 relative to 100 parts by weight of polyol.
In the range of 0.5 to 4 parts by weight, preferably in the range of 0.5 to 4 parts by weight, in the case of HFC-245fa, HFC-236ea and HFC-143, 0.1 to 10 parts by weight per 100 parts by weight of polyol is used. Within the range, preferably 1-10
It is in the range of parts by weight. If the amount of HFC used is less than the above range, it may not be possible to suitably miniaturize the cells of the obtained rigid urethane foam, while if it exceeds the above range, voids are generated in the obtained rigid urethane foam. There is a possibility that the thermal conductivity of the rigid urethane foam will be high.

The first component of the foaming agent in the present invention comprises cyclopentane and water.

The water is used as one component of the foaming agent for the formation of bubble nuclei of rigid urethane foam. When the amount of water used increases, carbon dioxide gas having a high thermal conductivity due to the reaction with isocyanate is generated. The generated amount increases, and as a result, the thermal conductivity of the rigid urethane foam as a whole increases and the bubble diameter of the rigid urethane foam increases.
Therefore, the amount of water used must be 1 part by weight or less based on 100 parts by weight of the polyol. The amount of water used is preferably within the range of 0.1 to 1 part by weight with respect to 100 parts by weight of the polyol. If the amount of water used is less than 0.1 part by weight, the formation of bubble nuclei will be insufficient, resulting in non-uniform foaming, and uniform and fine bubbles may not be obtained. If it exceeds the range, the amount of carbon dioxide gas having a high thermal conductivity due to the reaction with isocyanate is increased, and as a result, the thermal conductivity of the rigid urethane foam as a whole is increased or the bubble diameter of the rigid urethane foam is increased.

The amount of cyclopentane used is preferably in the range of 0.1 to 25 parts by weight, and more preferably in the range of 5 to 20 parts by weight, based on 100 parts by weight of the polyol. When the amount of the cyclopentane used is less than the above range, the amount of cyclopentane contributing to foaming is small, so that the foaming efficiency may decrease and the apparent density of the rigid urethane foam may increase, while the range above If it exceeds, the voids may be generated in the rigid urethane foam to reduce the thermal conductivity, or the strength of the obtained rigid urethane foam may be significantly reduced due to the inclusion of liquid cyclopentane.

As the above-mentioned isocyanate, for example, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, tolylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dichlorohexyl methane diisocyanate, triphenyl methane triisocyanate or these is used. Examples thereof include isocyanate partially modified by an appropriate method or by using an appropriate compound. Also,
You may use these in mixture of 2 or more types. Among these isocyanates, among them, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, tolylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and partial modification thereof with an appropriate method or with an appropriate compound. Isocyanate has high reactivity with polyol, low thermal conductivity,
It is preferable in that a rigid urethane foam having high strength can be obtained. The amount of the isocyanate used is preferably such that the NCO / OH ratio (the ratio of the isocyanate group in the isocyanate to the hydroxyl group in the polyol) is in the range of 1.00 to 1.40, and particularly 1 .10
It is preferable to use it in the range of 1.20.

The above-mentioned polyols include aromatic amines, polyhydric alcohols, sucrose, alkanolamines,
Examples thereof include polyether polyols having a hydroxyl value of 300 to 800 obtained by adding alkylene oxide to compounds such as polyamines and phenols. Examples of the aromatic amine include tolylenediamine, phenylenediamine, xylenediamine, naphthalenediamine, diphenylmethanediamine, and the like, and examples of the polyhydric alcohol and sucrose include ethylene glycol, propylene glycol, glycerin, hexanetriol, and the like. Trimethylolpropane, pentaerythritol, methylglycoside, sorbitol, sucrose and the like can be mentioned. Examples of the alkanolamine include ethanolamine, diethanolamine and triethanolamine, and examples of the polyamine include ethylenediamine and diethylenetriamine. Examples of the phenols include bisphenol A and the like. As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like can be used, and two or more kinds thereof may be mixed and used. Further, polycarboxylic acids such as adipic acid, succinic acid, maleic acid, fumaric acid, pyromellitic acid and anhydrides thereof, and polyols having a primary hydroxyl group (for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane). The hydroxyl value obtained by the condensation reaction with diol, trimethylolpropane, pentaerythritol, etc.) is 20
The polyester polyol of 0-600 is mentioned. Among these, the polyether polyol or the polyester polyol composed of the aromatic amine and the polypropylene glycol is preferable in that a hard urethane foam having a high reactivity with the polyol, a low thermal conductivity and a high strength can be obtained.

As the reaction catalyst, tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, pentamethyldiethylenetriamine, triethylenediamine, tetramethylpropylenediamine, dimethylethanolamine, tetramethylethylenediamine, dimethylcyclohexylamine, dimethylbenzylamine, Tertiary amines such as methylmorpholine and ethylmorpholine, or, for example, stannas octoate, stannas oleate, dibutyltin dilaurate,
Examples thereof include organotin compounds such as dibutyltin diacetate and organometallic compounds such as lead naphthenate and lead octylate. Among them, the tertiary amines are preferable in that they can further accelerate the urethane reaction. The amount of the reaction catalyst used is preferably in the range of usually 0.3 to 10 parts by weight with respect to 100 parts by weight of the polyol, from the viewpoint of optimizing the foamability and the curing rate of the rigid urethane foam. Further, it is preferably within the range of 1 to 5 parts by weight.

Examples of the foam stabilizers include organic silicone compounds, fluorochemical surfactants, cationic surfactants, anionic surfactants, nonionic surfactants, and the like. Among them, ethylene oxide and An organic silicone compound in which an addition polyether of propylene oxide is bonded to the main chain of siloxane as a side chain is preferable in that it has a large foam control power. The amount of the foam stabilizer used is in the range of 0.5 to 10 parts by weight with respect to 100 parts by weight of the polyol, from the viewpoint of exhibiting a sufficient foam stabilizing effect and not reducing the strength of the rigid urethane foam. It is more preferably in the range of 1 to 5 parts by weight.

Further, in the rigid polyurethane foam which is the foamed heat insulating material of the present invention, silica, talc, calcium carbonate, aluminum hydroxide, glass fiber, glass flakes, styrene beads, etc. are used as the filler, and tris (2) as the flame retardant. , 3-Dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2-dichloroethyl) phosphate, dimethylmethylphosphate, dibromopropanol, tetrabromobisphenol A and the like may be added.

The rigid urethane foam can be manufactured by the following method. That is, the polyol, foam stabilizer,
A low-boiling-point blowing agent mixer that is usually used with a liquid mixture in which a reaction catalyst and a first component of a blowing agent composed of cyclopentane and water are mixed in advance, and the specific HFC that is the second component of the blowing agent ( For example, a premix is prepared by mixing using Easy Floss manufactured by Canon Inc.). A urethane foaming machine that is usually used with this premix and the isocyanate (for example, H manufactured by Canon Inc.)
It can be produced by mixing and foaming using an E-40 type foaming machine or the like).

The foaming conditions are slightly different depending on the type of foaming machine, but usually the liquid temperature is preferably 15 to 40 ° C., more preferably 20 to 30 ° C. The discharge pressure is 8 to 18 MPa, and the discharge amount is 15 to
It is preferably 60 kg / min and the temperature of the mold is 35 to 55 ° C. Particularly preferable conditions are discharge pressure of about 13 MPa, discharge amount of about 30 kg / min, and mold temperature. The condition is about 45 ° C.

The rigid urethane foam, which is such a foamed heat insulating material, is used as, for example, a refrigerator, a freezer, a water heater, a rice cooker, other electric machinery, a heat insulating material for a building structure or a vehicle, or a heat insulating molded article. Can be used as

When manufacturing a heat-insulating box body using such a rigid urethane foam, after mixing the premix and the isocyanate as described above, they are foamed by using a high-pressure foaming machine and the like. The heat insulating box body is obtained by filling the gap formed between the inner box and the outer box of the box with the foam with an appropriate method.

Such a heat-insulating box can be used, for example, as a cabinet of a refrigerator or a freezer, a water heater, a heat-insulating wall of a rice cooker, and the like.

The hard urethane foam which is the foamed heat insulating material of the present invention and the heat insulating box body filled with this hard urethane foam do not need to be manufactured by using special equipment, and the conventional hard urethane foam is manufactured. It can be manufactured using equipment and conventional equipment for manufacturing a heat insulating box body filled with rigid urethane foam. In addition, in the above mixture comprising the polyol, the foam stabilizer, the reaction catalyst and the first component of the foaming agent, the specific H that is the second component of the foaming agent is added.
When the FC is further mixed, no special auxiliary agent or additive may be used.

The rigid urethane foam which is the foamed heat insulating material has a density of 25 to 60 k from the viewpoint of reducing the thermal conductivity.
It is g / m ³ , and it is preferable that the cell diameter be as fine as possible within the range in which the closed cell structure can be maintained.

From the viewpoint of reducing the power consumption of, for example, a refrigerator using a rigid urethane foam, it is desirable that the thermal conductivity be as small as possible, and it is usually 10 to 20 mW / mK although it depends on the application. It can be said to be the range of use.

Next, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0038]

EXAMPLE As a raw material for the foamed heat insulating material of this example, isocyanate: diphenylmethane diisocyanate (NCO% (weight basis) = 31) polyol: tolylenediamine having a hydroxyl value of ethylene oxide and propylene oxide added thereto 39
No. 0 Cyclopentane: manufactured by Nippon Zeon Co., Ltd., trade name: Zeon Solve HP water: deionized water Foam stabilizer: organic silicone compound (manufactured by Nippon Unicar Company:
Product name: L-5340) Reaction catalyst: Tetramethylhexamethylenediamine (manufactured by Kao Corporation, product name: Kaorizer No. 1) Specific HFC: HFC-134a, HFC-152a,
HFC-125, HFC-32, HFC-143a, H
FC-245fa, HFC-236ea, HFC-14
3 Other HFCs: HFC245ca, HFC356m
ff was used.

[Experimental Examples 1 to 21] The first amount of the polyol, the foam stabilizer, the reaction catalyst and the blowing agent in the amounts shown in Table 1 or 2 was used.
Cyclopentane, which is a component, and water in a metal container connected to the ground, under a dry nitrogen atmosphere at 30 ° C.
After mixing by stirring for 0 minutes, the mixture was put into a machine tank of a high-pressure foaming machine (HE-40, manufactured by Canon Inc.), and the inside of the tank was pressurized to 2-3 atm with dry nitrogen. After that, the HFCs listed in Table 1 or 2
Of the HFC was mixed by bubbling the mixture gas in the machine tank and the HFC in the amounts shown in Table 1 or 2 (however, in Experimental Examples 18 and 19, HFC Gas bubbling was not done). Further, this premix liquid was mixed with isocyanate in the mixing head of the high-pressure foaming machine, and the mixed liquid was fixed to a mold clamping device in advance with an outer box for a refrigerator (MR-12D) manufactured by Mitsubishi Electric Corp. It was injected into the space formed by the inner box. The injection amount varied depending on the type and amount of the foaming agent added, and was set to 115% by weight of the minimum filling amount.
After that, the mixed liquid was added to a high-pressure foaming machine (Canon Co., Ltd.).
Manufactured by HE-40).

From the obtained heat-insulating box, cut into a predetermined size with a band saw, a cutter knife, or the like, take out a test piece of hard urethane foam in which the mixed solution is foamed, and conduct heat conduction of this test piece by the following method. The rate and the average bubble diameter were measured to evaluate the state of void generation. Table 1 shows the results.

Thermal conductivity measuring method: 200 (W) × 20
A test piece of 0 (L) × 20 (T) mm ³ of a rigid urethane foam is measured using TCA-8 manufactured by Anacon at an average temperature of 23.9 ° C. Method of measuring average cell diameter: The surface of the sample used for measuring the thermal conductivity is observed with an electron microscope (SEM), the diameter of about 100 cells is measured, and the average value is calculated. Evaluation method of void generation state: After measuring the bulk volume by accurately measuring the dimensions of the three sides of a rigid urethane foam test piece cut into about 30 mm square with a vernier caliper, an air comparison hydrometer (Tokyo Science Co., Ltd. ), 1000 type)
Then, the actual volume of the test piece is obtained. When the ratio (%) of the actual volume to the bulk volume is D (D = actual volume / bulk volume × 100), the void occurrence state can be determined by the value of D. The judgment is based on the following criteria. Very low: D ≧ 95 Low: 85 ≦ D ≦ 95 High: D <85

[0042]

[Table 1]

[0043]

[Table 2]

From the above results, it was found that by using a specific HFC as the second component of the foaming agent in the foamed heat insulating material using cyclopentane, which is a foaming agent having no adverse effect on the global environment, and water as the first component of the foaming agent. It can be seen that the bubbles of the foamed heat insulating material can be made finer and the thermal conductivity of the foamed heat insulating material can be lowered. Further, it was found that the effect of making the bubbles finer and lowering the thermal conductivity is greater as the amount of water used is smaller, and the effect is 1.5% with respect to 100 parts by weight of polyol. It can be seen that it is remarkable when the amount is less than the weight part.

Further, when a specific HFC is used as the second component of the foaming agent, if the amount of the specific HFC is too large, many voids are generated in the foamed heat insulating material, and the thermal conductivity seems to be slightly inferior. It turns out that there is a chance.

[0046]

EFFECT OF THE INVENTION An isocyanate, a polyol, a foaming agent, a reaction catalyst and a foam stabilizer are mixed and stirred to obtain a mixture, and a foamed heat insulating material obtained by foaming the mixture, wherein the foaming agent is cyclo It comprises a first component composed of pentane and water, and a second component composed of at least one HFC having a boiling point of 20 ° C. or lower at room temperature, and the amount of water used is 100 parts by weight of the polyol component. The foamed heat insulating material of the present invention, whose total amount is 1.5 parts by weight or less, has fine bubbles and has a low thermal conductivity, and therefore has excellent heat insulating performance. Also, this foam insulation can be foamed using a conventional high-pressure foaming machine. These foamed heat insulating materials can be suitably applied to a heat insulating box body such as a refrigerator and a freezer, and can sufficiently suppress heat transfer through the heat insulating box body, so that they have an excellent effect of keeping cold or keeping warm.

Furthermore, since the ozone depletion potential of cyclopentane and HFC used as a blowing agent is zero,
It does not adversely affect the global environment.

As the HFC, HFC-134
a, HFC-152a, HFC-32 or HFC-1
By using 43a, the bubbles in the rigid urethane foam are miniaturized, and the thermal conductivity of the rigid urethane foam is reduced.

As the HFC, HFC-134
a, HFC-152a, HFC-32 or HFC-1
When 43a is used, the amount of HFC used is 0.1 to 5 parts by weight with respect to 100 parts by weight of the polyol, whereby the bubble diameter of the foamed heat insulating material can be sufficiently miniaturized, and voids Occurrence can be suppressed.

The HFC is HFC-245.
By using fa, HFC-236ea, or HFC-143, bubbles in the rigid urethane foam are miniaturized, and the thermal conductivity of the rigid urethane foam is reduced.

The HFC is HFC-245.
When using fa, HFC-236ea or HFC-143, the amount of HFC used is 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyol, so that the bubble diameter of the foamed heat insulating material is sufficiently miniaturized. It is possible to suppress the occurrence of voids.

Heat insulation is preferably performed by using an insulating box body composed of an outer box, an inner box, and the foamed heat insulating material foam-filled in a gap formed between the outer box and the inner box. sell.

Claims (6)

[Claims] 1. A foamed heat insulating material obtained by mixing and stirring an isocyanate, a polyol, a foaming agent, a reaction catalyst and a foam stabilizer to obtain a mixture, and foaming the mixture, wherein the foaming agent is a cycloolefin. It comprises a first component consisting of pentane and water, and a second component consisting of at least one kind of hydrofluorocarbon having a boiling point of 20 ° C. or lower at room temperature, and the amount of water used is 100 parts by weight of the polyol component. On the other hand, a foamed heat insulating material whose content is 1.5 parts by weight or less. 2. The hydrofluorocarbon is 1,
1,1,2-tetrafluoroethane (HFC-134
a), 1,1-difluoroethane (HFC-152
a), 1,1,1,2,2-pentafluoroethane (H
FC-125), difluoromethane (HFC-32) and 1,1,1-trifluoroethane (HFC-143
The foamed heat insulating material according to claim 1, which is at least one selected from the group consisting of a). 3. The foamed heat insulating material according to claim 2, wherein the amount of the hydrofluorocarbon used is in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the polyol. 4. The hydrofluorocarbon is 1,
1,1,3,3-Pentafluoropropane (HFC-2
45fa), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and 1,1,2-trifluoroethane (HFC-143). The foamed heat insulating material according to claim 1. 5. The foamed heat insulating material according to claim 4, wherein the amount of the hydrofluorocarbon used is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyol. 6. An insulating box comprising an outer box, an inner box, and the foamed heat insulating material according to claim 1, filled in a gap formed between the outer box and the inner box. body.