JPH0598061A - Rigid polyurethane foam, production thereof, thermal insulation material, and refrigerator using same - Google Patents

Abstract

PURPOSE:To produce a rigid polyurethane foam using a blowing agent contg. little or no CFC of which the use is regulated. CONSTITUTION:Water, at least one blowing agent selected from the group consisting of 2,2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-monofluoroethane, and at least one blowing agent selected from the group consisting of an HCFC having a b. p. of 0 deg.C or lower and an HFC are used in combination as a blowing agent. Thus, a low-density rigid polyurethane foam having balanced properties, esp. excellent in dimensional stability, is obtd. without using a CFC of which the use is regulated to prevent air pollution and to protect the ozone layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rigid polyurethane foam which does not use CFC (chloro-fluoro-carbon) subject to CFC regulation as a foaming agent and has a particularly low density and excellent dimensional stability, a method for producing the same and a heat insulating material. And a refrigerator using the same.

[0002]

2. Description of the Related Art Rigid polyurethane foams are well known in the prior art in which a polyol component and an isocyanate component are reacted in the presence of a foaming agent, a reaction catalyst and a foam stabilizer. In the prior art, in order to obtain a rigid polyurethane foam having closed cells and excellent heat insulation with high productivity, the foaming agent has a very low gas thermal conductivity, a low boiling point, and a liquid at room temperature. Therefore, trichloromonofluoromethane, which has excellent properties such as nonflammability and low toxicity, has been commonly used. As a conventional technique related to the method for producing a rigid polyurethane foam of this type, there is, for example, JP-A-59-84913.

[0003]

In the above-mentioned prior art, trichloromonofluoromethane (CCl ₃ F), which is commonly used as a blowing agent, is useful because it can realize a rigid polyurethane foam having a low density and excellent dimensional stability. It has been regarded as something. However, this substance is difficult to separate C
FC [Chloro Fluoro Carbon (Chloro Fluoro
Carbon is an abbreviation for chlorofluoro-substituted hydrocarbon]
It is said that if this kind of persistent CFC is released into the atmosphere, it will destroy the ozone layer in the stratosphere and raise the surface temperature due to the greenhouse effect, which has become a global environmental pollution problem in recent years. ing.

At present, the production amount and consumption amount of this kind of persistent CFC are regulated, and eventually they cannot be used. Therefore, HCFC, which is easily degradable as an alternative blowing agent, is used.
[Hydro Chloro Fluoro Carbon (Hydoro Chl
oroFluoro Carbon)] 2,2-dichloro-1,
1,1-trifluoroethane (CHCl ₂ CF ₃ ) and 1,1-dichloro-1-monofluoroethane (CH ₃ C
Various studies have been made on rigid polyurethane foams using Cl ₂ F), but rigid polyurethane foams having well-balanced physical properties, particularly those having low density and excellent dimensional stability, have not yet been obtained.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and the first object thereof is to use a readily decomposable foaming agent other than CFC and to have a balanced physical property. , Especially low density and excellent dimensional stability rigid polyurethane foam, the second purpose is the production method thereof, the third purpose is the heat insulating material formed thereby, and the fourth purpose is to use it. It is to provide each refrigerator.

[0006]

The first object of the present invention is a rigid polyurethane foam obtained by reacting a polyol component and an isocyanate component in the presence of a blowing agent containing water. As the component composition, water,
A first organic blowing agent comprising at least one of 2,2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-monofluoroethane, and hydro-chloro having a boiling point of 0 ° C. or less. A second organic foaming agent comprising at least one of fluoro carbon (HCFC) and hydro fluoro carbon (HFC), wherein at least the foaming agent component is contained in the closed cells of the polyurethane foam. With rigid polyurethane foam,
To be achieved.

A second object is a method for producing a rigid polyurethane foam, which comprises forming a polyol component and an isocyanate component by reacting them in the presence of a foaming agent, a reaction catalyst and a foam stabilizer. Water, 2,2-
Dichloro-1,1,1-trifluoroethane and 1,1
A first organic blowing agent comprising at least one of dichloro-1-monofluoroethane and at least one of hydro-chloro-fluorocarbon (HCFC) and hydro-fluorocarbon (HFC) having a boiling point of 0 ° C. or less. This is accomplished by a method of making a rigid polyurethane foam that is composed of a mixed component with a second organic blowing agent that is a seed.

Furthermore, the third object is achieved by using a rigid polyurethane foam capable of achieving the first object as a heat insulating material.

Further, the fourth object is achieved by a refrigerator comprising a heat insulating section made of a heat insulating material capable of achieving the third object.

[0010]

The feature of the present invention resides in the composition of the blowing agent to be used, and it includes water and at least 2,2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-monofluoroethane. One first organic foaming agent and boiling point 0 ° C
The use is in combination with at least one second organic blowing agent of the following HCFC and HFC.

Since the above first organic foaming agent has a good affinity with the resins, when these are used as the foaming agent,
Generally, the mechanical strength of the obtained foam is lowered and the dimensional stability is deteriorated. Furthermore, the boiling points are 27.5 ° C and 3 respectively.
The temperature is 2.0 ° C, which is higher than that of conventional trichloromonofluoromethane (so-called CFC) of 23.8 ° C. Especially at low temperature, the vapor pressure of the gas in the bubbles becomes low, so that the shrinkage force of the foam increases. It adversely affects the dimensional stability. Therefore, when the first organic foaming agent is used, it is necessary to make the density higher than in the past, and it has been difficult to reduce the density only with these.

Therefore, in the present invention, HCFC having a boiling point of 0 ° C. or lower is used as the second organic foaming agent in the first organic foaming agent,
By using HFC in combination, the vapor pressure in the bubbles is increased, and the vapor pressure reduces the shrinkage force of the foam at low temperatures, resulting in a low density C with excellent dimensional stability.
It is possible to obtain FC-less rigid polyurethane foam.

H of the second organic blowing agent used in the present invention
Examples of CFCs include monochlorodifluoromethane (CHClF ₂ , boiling point: −40.8 ° C.), 2-monochloro-1,1,1,2-tetrafluoroethane (CHCl
FCF ₃ , boiling point: -12.0 ° C), 1-monochloro-1,
1-difluoroethane (CH ₃ CClF _2, boiling point: -9.
7 ° C.) and the like. Also, as HFC of the second organic foaming agent, for example, 1,1,1,2,2-pentafluoroethane (CHF ₂ CF ₃ , boiling point: −48.5) is used.
C), 1,1,1,2-tetrafluoroethane (CH ₂
FCF ₃ , boiling point: −26.3 ° C., 1,1-difluoroethane (CH ₃ CHF ₂ , boiling point: −25.0 ° C.) and the like can be mentioned. Among these organic foaming agents, the one having a lower boiling point has a higher vapor pressure, has less shrinkage of the foam at low temperature and is effective in improving dimensional stability, but considering workability and cost, monochlorofluoro Most preferred is methane.

The blowing agent is used in a total amount of 20 to 70 parts by weight based on 100 parts by weight of the polyol component, and the first organic blowing agent is 15 to 65 parts by weight, more preferably 25 parts by weight.
It is preferable to use ˜55 parts by weight.

The second organic foaming agent (at least one of HCFC and HFC) having a boiling point of 0 ° C. or lower is preferably used in an amount of 5 to 30 parts by weight. Furthermore, it is preferable to use 0.5 to 3 parts by weight of water based on 100 parts by weight of the polyol component.

In the present invention, a rigid polyurethane foam is produced by reacting a polyol component and an isocyanate component in the presence of a reaction catalyst and a foam stabilizer using the above-mentioned foaming agent.

The polyol component used in the present invention has an OH value of 30 obtained by adding an alkylene oxide to a compound such as an aromatic amine, a polyhydric alcohol, sucrose, an alkanolamine, a polyamine or a phenol.
0 to 800 polyether polyols are used.

Examples of the aromatic amine include tolylenediamine, phenylenediamine, xylenediamine,
Naphthalenediamine, diphenylmethanediamine, etc .;
Examples of the polyhydric alcohol and sucrose include ethylene glycol, propylene glycol, glycerin, hexanetriol, trimethylolpropane, pentaerythritol, methyl glucoside, sorbitol, sucrose, and the like; examples of the alkanolamine include ethanolamine, diethanolamine, and the like. Triethanolamine and the like; examples of the polyamines include ethylenediamine and diethylenetriamine, and examples of the phenols include those represented by bisphenol A.

As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like can be used. You may use these polyether polyols in mixture of 2 or more types. Further, adipic acid, succinic acid, maleic acid, fumaric acid, phthalic acid, polycarboxylic acids such as pyromellitic acid and their anhydrides, and a polyol having a primary hydroxyl group (for example, ethylene glycol, diethylene glycol,
OH number obtained by condensation with propylene glycol, dipropylene glycol, butanediol, trimethylolpropane, pentaerythritol, etc.
You may use 600 polyester polyols together.

On the other hand, examples of the isocyanate component used in the present invention include diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, tolylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, triphenylmethane. Examples thereof include triisocyanates and isocyanates partially modified with various methods and compounds. These two
You may use it in mixture of 2 or more types. These isocyanates have an NCO / OH ratio (NC
The ratio (O group to OH group) is preferably in the range of 1.00 to 1.20, particularly preferably 1.10.

Examples of the reaction catalyst used in the present invention include tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, pentamethyldiethylenetriamine, triethylenediamine, tetramethylpropylenediamine, dimethylethanolamine, tetramethylethylenediamine, dimethylcyclohexene. Tertiary amines such as sialamine, dimethylbenzylamine, methylmorpholine and ethylmorpholine; or organotin compounds such as stannas octoate, stannas oleate, dibutyltin dilaurate, dibutyltin diacetate, lead naphthenate, octyl Examples thereof include organometallic compounds such as lead acid and other organolead compounds. These two
You may use it in mixture of 2 or more types. These reaction catalysts are
It is used in an amount of 0.3 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polyol component.

Further, as the foam stabilizer, an organic silicone compound, a fluorine-based surfactant, a cationic surfactant, an anionic surfactant, a nonionic surfactant, which are used in the production of ordinary rigid polyurethane foams, are used. Agent can be used, and is 0.5 per 100 parts by weight of the polyol component.
~ 5 parts by weight, preferably 1 to 3 parts by weight are used. The rigid polyurethane foam of the present invention may optionally contain additives such as a flame retardant, a filler, a reinforcing fiber and a coloring agent which are usually used.

The rigid polyurethane foam of the present invention can be produced by injection foaming, spray foaming, etc. by the flow method. Further, these foaming can be performed by any one of the one-shot method, the quasi-prepolymer method and the prepolymer method.

The rigid polyurethane foam may be produced by an ordinary foaming machine used in the art, for example, Pu-30 type foaming machine manufactured by Promart Co., Ltd. is used. The foaming conditions will vary slightly depending on the type of foaming machine, but normally the liquid temperature is 18 to 30 ° C and the discharge pressure is 80 to 150k.
g / cm ² , discharge rate 15 to 30 kg / min, mold temperature 35
The liquid temperature is preferably 25 ° C, the discharge pressure is 100 kg / cm ² , the discharge rate is 25 kg / min, and the mold temperature is 40 ° C.

The CFC-less rigid polyurethane foam obtained by the present invention has a density equivalent to that of a conventional practical product,
Or even lower than that, with a free foam density of 19-
The foam density of the panel is 26 to 29 kg / m ³ at 21 kg / m ^3.
Is. Moreover, well-balanced physical properties are obtained, and the dimensional stability and thermal conductivity of the conventional CFC are low despite the low density.
It is as good as or better than the rigid polyurethane foam using. For this reason, it is extremely excellent especially as a heat insulating material for refrigerators, etc.
It can be effectively used as a heat insulating material or a heat insulating molded article for building structures and vehicles. Furthermore, in addition to their use as heat insulating materials, they can be effectively used as fishing buoys and other buoyancy materials by utilizing the properties of low specific gravity and hardness.

[0026]

EXAMPLES Hereinafter, examples of the present invention will be described in more detail in comparison with comparative examples. In the description of the examples, "parts" and "%" are based on weight unless otherwise specified. Before starting the description of specific examples, Comparative Example 1 will be described here first as an example of a conventional method for producing a typical rigid polyurethane foam, and the physical properties thereof are shown in Table 1.

Comparative Example 1 Tolylenediamine, EO (abbreviation of ethylene oxide) and PO were used as polyol components.
65% polyol with an OH number of 470 (abbreviation of propylene oxide) and O with PO added to sucrose
14% of polyol having H value of 460, polyol 6 having OH value of 470 with EO and PO added to diethanolamine and OH value of 4 having EO and PO added to propylene glycol
100 parts of a polyol mixture containing 15% of 40 polyols and having an average OH number of 465; 1.5 parts of water and trichloromonofluoromethane (1 of CFC as a blowing agent).
Seed) 46 parts; 2: as catalysts, tetramethylhexamethylenediamine (trade name: Kao Riser No. 1 manufactured by Kao Corporation) and trimethylaminoethylpiperazine (trade name: Kao Riser No. 8 manufactured by Kao Corporation): 2.5 parts mixed with 1; 1.5 parts of an organic silicone compound (using a trade name of Nippon Unicar: L-5340) as a foam stabilizer; and diphenylmethane diisocyanate (NCO% =) as an isocyanate component. 31) The required amount (NCO / OH = 1.10) was used to foam and cure. Foam curing conditions include a liquid temperature of 25 ° C. and a discharge pressure of 1.
00 Kg / cm ² , discharge rate 25 Kg / min, mold temperature 40
Performed at ° C.

<Examples 1 to 7> and <Comparative Examples 2 to 5> Using the foaming agents shown in Table 1, 50% polyol of OH value 510 obtained by adding EO and PO to tolylenediamine as a polyol component, bisphenol O with EO added to A
12% of polyol having H value of 280, 20% of polyol having OH value of 690 in which PO is added to trimethylolpropane,
100 parts of a polyol mixture containing 8% of OH number 460 polyol with PO added to sucrose and 10% of OH number 510 polyol added with EO and PO to diethanolamine, and having an average OH value of 515 100 parts; tetramethyl as catalyst 1.5 parts of hexamethylenediamine and pentamethyldiethylenetriamine (trade name of Kao Corporation:
1.0 part of Kaorizer No. 3; organosilicon compound as a foam stabilizer (trade name of Nippon Unicar Co., Ltd .:
SZ-1628) 2.0 parts; and 7: 3 mixture of diphenylmethane diisocyanate as an isocyanate component and sucrose tolylene diisocyanate prepolymer (NCO% = 32) Necessary amount (NC
O / OH = 1.10) was used to foam and cure. The foaming and curing conditions were the same as in Comparative Example 1 above. The results are shown in Table 1.

In Table 1, the physical properties were examined as follows. (1) Free foam density: Inner dimension 200 × 200 × 200m
Density (kg / m ³ ) when m is foamed in a veneer mold.

(2) Foam density of panel: Internal size 400W
Density (kg / m ³ ) when foaming is performed at a mold temperature of 40 ° C. in a mold whose material is (width) × 600 L (length) × 35 T (thickness) mm and is made of Al.

(3) Fluidity: Panel foam density-free foam density. ◯: less than 8.0 Δ: 8.0 to 9.0 ×: greater than 9.0

(4) Thermal conductivity: 200 W × 200 L × 5
0Tmm panel form, Anacon model 88
It was measured using a mold at an average temperature of 23.9 ° C. ◯: 14.0 × 10 to ³ Kcal / m · h · ° C or less Δ: 14.0 to 15.0 × 10 to ³ Kcal / m · h · ° C ×: 15.0 × 10 to ³ Kcal / m · Greater than h ° C.

(5) Dimensional stability: 400W × 600L ×
The rate of change of the thickness dimension when a 35 Tmm panel foam is left at -20 ° C for 48 hours. ◯: less than 0.8% Δ: 0.8 to 2.0% x: greater than 2.0%

[0034]

[Table 1]

As is clear from Table 1, Comparative Example 1 shows an example of a conventional representative rigid polyurethane foam using trichloromonofluoromethane as a blowing agent. Although it has good characteristics, it uses a CFC foaming agent, which has become an environmental problem now.

On the other hand, in Comparative Examples 2 and 3, 2,2-dichloro-1, which is HCFC as an alternative blowing agent, is used.
1,1-trifluoroethane and 1,1-dichloro-1
-This is an example using monofluoroethane, which has no environmental problems, but has a higher density than Comparative Example 1 and poor distribution,
Not preferable. In Comparative Examples 4 and 5, the amount of the foaming agent used in Comparative Examples 2 and 3 was increased, and the foam density of the panel was lowered to the level of Comparative Example 1. However, the dimensional stability was remarkably reduced, which is preferable. I know there isn't.

On the other hand, the foaming agent of the present invention comprises water and at least one of 2,2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-monofluoroethane. In Examples 1 to 7 in which the first organic foaming agent was used in combination with at least one of HCFC and HFC having a boiling point of 0 ° C. or less as the second organic foaming agent, the panel foaming density was 27.0. 27.5 kg / m
Despite having an extremely low density of ³ and lower than that of Comparative Example 1, the dimensional stability was as excellent as that of Comparative Example 1 using conventional trichloromonofluoromethane as a foaming agent, and the thermal conductivity and It can be seen that the fluidity is also excellent. In particular, as shown in Example 1, water and 2,2-dichloro-1,1,1 were used as the blowing agent.
-A combination of a first organic blowing agent made of trifluoroethane and a second organic blowing agent made of monochlorodifluoromethane is used to obtain density, fluidity, thermal conductivity, dimensional stability and workability. Was the best balance.

In the above-mentioned examples, from the viewpoint of solving the ultimate problem of environmental damage, an example using a foaming agent containing no CFC was shown. However, for the time being, as one step in the process of reaching there, it is realistic to gradually reduce the amount of CFCs used while substituting a part of CFCs currently used by the blowing agent according to the present invention. Seem.

As described above, HCFC or HFC, which has a very small influence on the destruction of the ozone layer and is not subject to the regulation, is used as the foaming agent, and is equivalent to the conventional product.
Alternatively, it was possible to obtain a CFC-less rigid polyurethane foam having an even lower density and excellent fluidity. In addition, the physical properties of thermal conductivity and dimensional stability are not inferior to those of conventional products, and have excellent properties. Therefore, there is an effect that the cost of various heat insulating materials can be significantly reduced.

<Embodiment 8> FIG. 1 shows an example in which the rigid polyurethane foam of the present invention is applied to a wall material for construction, a heat insulating material constituting a casing of a cold insulation vehicle and the like. First, as shown in FIG. 1 (a), the same raw material components for forming rigid polyurethane foam as in Examples 1 to 7 were introduced from the injection head 2 of the flat hollow housing 1 formed of a metal plate such as aluminum. Inject the mixed solution containing and foam in the same way,
By curing, a heat insulating casing having a cross-sectional shape shown in FIG. 1 (b) was formed. Note that FIG. 1B shows a cross section taken along the line AA ′ in FIG. 1A, and the hollow portion is filled with the foamed and cured rigid polyurethane foam 4.

Although the drawing is omitted in injecting the above-mentioned mixed solution into the hollow casing 1, a large number of hollow casings 1 are previously stored in parallel in a heat-retaining tank and kept at 35 to 45 ° C. After a fixed amount is injected in, the injection head 2 is sealed.
The opening 3 is a gas vent when the mixed solution is injected, and also serves as a gas vent when the foam is cured. The heat-insulating housing thus obtained is effective not only as a wall material for construction of houses and the like, but also as a heat-insulating material for the outer wall of a cold-insulated vehicle and in other fields conventionally used. Is applicable to.

Example 9 FIG. 2 shows an example in which the rigid polyurethane foam of the present invention is used as a heat insulating material filled in the outer box of a refrigerator. That is, this figure schematically shows how the hollow portion of the refrigerator outer box 21 is filled with the hard polyurethane 24.

The procedure is as follows. (1) The refrigerator outer box 21 is incorporated into a foaming jig (not shown) which has been preheated to 35 to 45 ° C. (2) Inject the rigid polyurethane foam stock solution adjusted to a liquid temperature of 25 ° C. from the injection head 22. (3) The injected stock solution foams and fills the entire outer box. (4) After the injection, perform an aftercure and remove the mold in about 5 minutes.

In the figure, the arrow 25 indicates the flow of the rigid polyurethane foam, and 23 indicates the degassing port. In consideration of the gas venting and the flow of urethane foam, the refrigerator outer box 21 is held inclined at an angle of θ. Thus, the same rigid polyurethane foam stock solution (mixed solution) as in Examples 1 to 7 was used to foam and cure in the same manner to fill the rigid polyurethane foam having the physical properties shown in Table 1. Manufactured a refrigerator.

[0045]

As described above, according to the present invention,
It is possible to realize a rigid polyurethane foam which has well-balanced physical properties as a heat insulating material and which has particularly low density and excellent dimensional stability by reducing the amount of CFC used or not using it at all. It was possible to achieve the intended purpose, including. As described above, according to the present invention, since the CFC subject to air pollution control can be reduced by 100%, the risk of ozone layer depletion is extremely reduced, and the significance thereof is extremely significant from the viewpoint of environmental protection.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process of a heat insulating material according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a filling state of a rigid polyurethane foam in a refrigerator outer box according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hollow housing, 2, 22 ... Injection head, 3, 23 ... Gas vent, 4, 24 ... Rigid polyurethane foam, 21 ... Refrigerator outer box, 25 ...
Form flow direction, θ… inclination angle.

Claims (12)

[Claims] 1. A rigid polyurethane foam obtained by reacting a polyol component and an isocyanate component in the presence of a blowing agent containing water, wherein the component composition of the blowing agent is water and 2,2-dichloro- A first organic blowing agent comprising at least one of 1,1,1-trifluoroethane and 1,1-dichloro-1-monofluoroethane, and a hydro-chloro-fluoro-carbon (H
CFC) and a second organic blowing agent comprising at least one of hydrofluorocarbon (HFC), and a rigid polyurethane foam containing at least the blowing agent component in the closed cells of the polyurethane foam. 2. The content of the foaming agent is 20 to 70 parts by weight per 100 parts by weight of the polyol component, and the composition of the foaming agent is 0.5 to 3 parts by weight of water and 15 to 65 parts by weight. The rigid polyurethane foam of claim 1 comprising a first organic blowing agent and 5 to 30 parts by weight of a second organic blowing agent. 3. A method for producing a rigid polyurethane foam, which comprises reacting a polyol component and an isocyanate component in the presence of a foaming agent, a reaction catalyst and a foam stabilizer, wherein the foaming agent is water and 2 , 2-dichloro-1,
1,1-trifluoroethane and 1,1-dichloro-1
A first organic blowing agent comprising at least one of monofluoroethane and at least one of hydro-chloro-carbon (HCFC) and hydro-fluoro-carbon (HFC) having a boiling point of 0 ° C. or lower. A method for producing a rigid polyurethane foam composed of a mixed component of the organic foaming agent of 2. 4. The content of the foaming agent is the polyol component 10
20 to 70 parts by weight with respect to 0 parts by weight, and the composition of the blowing agent is 0.5 to 3 parts by weight of water, and the first organic blowing agent 1
5 to 65 parts by weight and a mixed component of 5 to 30 parts by weight of the second organic foaming agent, and a reaction catalyst of 0.3 to 10 parts by weight,
The method for producing a rigid polyurethane foam according to claim 3, wherein the foam stabilizer is 0.5 to 5 parts by weight. 5. The above HCFC is replaced with monochlorodifluoromethane (CHClF ₂ ), 2-monochloro-1,1,1,2.
- tetrafluoride ethane (CHClFCF ₃₎ and 1-monochloro-1,1-difluoroethane (CH ₃ CCl
F ₂ ) and HFCs of 1, 1, 1,
2,2-pentafluoroethane (CHF ₂ CF ₃ ), 1,
The method for producing a rigid polyurethane foam according to claim 3, which comprises at least one of 1,1,2-tetrafluoroethane (CH ₂ FCF ₃ ) and 1,1-difluoroethane (CH ₃ CHF ₂ ). 6. A polyether having an OH value of 300 to 800 by adding an alkylene oxide to the above-mentioned polyol component to at least one compound of aromatic amine, polyhydric alcohol, sucrose, alkanolamine, polyamine and phenol. The method for producing a rigid polyurethane foam according to claim 3, comprising a polyol. 7. The isocyanate component is diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, tolylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
The method for producing a rigid polyurethane foam according to claim 3, comprising at least one of dicyclohexylmethane diisocyanate and triphenylmethane triisocyanate. 8. The ratio NCO / OH of NCO groups of the isocyanate to OH groups of the polyol is 1.00 to 1.00.
The method for producing a rigid polyurethane foam according to any one of claims 3 to 6, which is defined as 1.20. 9. The method for producing a rigid polyurethane foam according to claim 3, wherein the catalyst comprises at least one of a tertiary amine and an organometallic compound. 10. The foam stabilizer is an organic silicone compound,
At least one of a fluorine-based surfactant, a cationic surfactant, an anionic surfactant and a nonionic surfactant.
The method for producing a rigid polyurethane foam according to claim 3, which is used as a seed. 11. A heat insulating material comprising the rigid polyurethane foam according to claim 1. 12. A refrigerator comprising a heat insulating member made of the rigid polyurethane foam according to claim 11, which constitutes a heat insulating portion.