JPH0790101A - Thermally insulating foam and thermally insulated box - Google Patents

Abstract

PURPOSE:To produce a thermally insulating polyurethane foam contg. few froth voids and excellent in thermal insulating properties with safety by using a blowing agent comprising specific hydrofluorocarbons. CONSTITUTION:A polyurethane foam is produced by mixing an org. polyisocyanate, a polyol, water, a catalyst, a foam stabilizer, and a blowing agent comprising 20wt.% or less of 1, 1, 1-trifluoroethane and 80wt.% or more of 1, 1, 1, 2-tetrafluoroethane. More specifically, a thermally insulated box is obtd. by mixing the polyol, the catalyst, the stabilizer, and the blowing agent in a specified ratio to give a premix, mixing the premix with the polyisocyanate in a specified ratio with a high-pressure foaming machine, and injecting the resulting mixture into the space between outer and inner boxes to allow the mixture to foam.

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 used in refrigerators, freezers, etc., and a heat insulation box body filled with the foam insulation material.

[0002]

2. Description of the Related Art In recent years, chlorofluorocarbons (hereinafter C
Environmental problems such as ozone layer depletion and global warming due to hydrochlorofluorocarbon (hereinafter referred to as HCFC) have been attracting attention. Is CF
Organic polyisocyanate for the purpose of reducing the amount of C used.
1,1-dichloro-2,2, a hydrochlorofluorocarbon that is a substitute for CFC and has little effect on ozone layer depletion, using a carbon dioxide gas obtained by the reaction of water with water as a part of the blowing agent. Various improvement efforts are being investigated, such as foaming with 1,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, monochloro-difluoromethane, and 1-chloro-1,1-difluoroethane.

Further, 1,1-difluoroethane, difluoromethane, 1,1,1, which are hydrofluorocarbons (hereinafter referred to as HFC), which have no effect on ozone destruction,
Various improvements are being studied for foaming with 1-trifluoroethane, 1,1,1,2-tetrafluoroethane (hereinafter referred to as HFC134a), and "Urethane International Forum 93" (May 10, 1993). (Held on 12th)
Allied-Signal Inc by Blowing Agents: The Next Gen
In the report of "eration", it is stated that 1,1,1-trifluoroethane (hereinafter referred to as HFC143a) is applied alone as a foaming agent for a foamed heat insulating material.

[0004]

Hydrofluorocarbon has no effect on ozone layer depletion and is essential for global environmental protection. Of these, HFC14
3a has flammability, and it is necessary to introduce and maintain new equipment such as explosion-proof equipment in order to apply it alone as a foaming agent for foamed heat insulating material, and it is a heavy load on safety management.

As described above, in applying the HFC 143a which has no influence on the ozone layer depletion, it has been an important issue to find a means that can be applied safely and easily in terms of measures against flammability.

In view of the above problems, the present invention has a main purpose of protecting the global environment, has no effect of depleting the ozone layer, has very little effect on global warming, and has a boiling point of 0 ° C. or less.
HFC143a with extremely low gas thermal conductivity in FC
Even when used as a foaming agent for foamed insulation, it can be safely used without problems in mass production and fire prevention, and it provides high-quality foamed insulation with few froth voids and excellent foam insulation performance. is there.

[0007]

In order to solve the above problems, the present invention provides an organic polyisocyanate, a polyol, water,
1,1,1-trifluoroethane as a catalyst, foam stabilizer and blowing agent component and 1,1,1,2-of 80% by weight or more of the blowing agent component
Tetrafluoroethane is mixed and stirred to generate foam, thereby obtaining a foamed heat insulating material.

Further, as an outer box, an inner box, and an organic polyisocyanate, a polyol, water, a catalyst, a foam stabilizer, and a foaming agent component which are foam-filled in a space formed by the outer box and the inner box. A heat-insulating box body made of foamed heat-insulating material produced by foaming by mixing and stirring 1,1,1-trifluoroethane and 80% by weight or more of the foaming agent component of 1,1,1,2-tetrafluoroethane. is there.

[0009]

With the above structure, the combustibility of HFC143a enters the non-combustible region by the addition and mixing of 80% by weight or more of the foaming agent component of HFC134a, and the combustibility is eliminated as a foaming agent mixed gas.

Therefore, the foaming agent having an ozone depletion potential of 0 can be easily applied as a foaming agent for a foamed heat insulating material without requiring safety measures such as explosion-proof equipment.

Further, in HFCs having a boiling point of 0 ° C. or lower,
Since 80% by weight or more of the foaming agent component is added and mixed with HFC134a, which has a relatively good compatibility with the polyol, the froth void due to bumping at the time of foaming can be eliminated, and a foamed heat insulating material having excellent appearance quality can be obtained.

Further, a foamed heat insulating material to which a mixed gas of HFC143a as a foaming agent component and 80% by weight or more of HFC134a as a foaming agent component is applied as a foaming agent is HFC14.
Since the gas thermal conductivity of 3a is lower than that of HFC134a, the foam heat insulating performance is also greatly improved as compared with the HFC134a single foam heat insulating material.

[0013]

EXAMPLES Hereinafter, the foamed heat insulating material of the present invention will be described with reference to examples.

Table 1 shows the raw material formulation of one example. Polyol A is an aromatic amine type polyether polyol having a hydroxyl value of 460 mgKOH / g, catalyst A is Kaoizer No. 1 manufactured by Kao Corporation, and foam stabilizer A is a fluorocarbon type surfactant. Sumitomo 3M FC-170C, blowing agent is HFC1
43a and HFC134a, each raw material is mixed in a predetermined mixing part number to form a premix component.

On the other hand, the isocyanate component is an organic polyisocyanate consisting of a crude MDI having an amine equivalent of 135.
It is

The premix component and the isocyanate component thus prepared and mixed are mixed and stirred at a predetermined mixing number, foamed by a high-pressure foaming machine, and filled in a box body composed of an inner box and an outer box. Got the body The foam thermal conductivity, the foam density, the presence or absence of the blowing agent mixed gas combustibility, and the foam froth void state of the urethane foam at this time are also shown in Table 1 (Examples 1 and 2).

Regarding the flammability of the mixed gas of the foaming agent, a match was used as an ignition source by the ASTM E-681 method.

At the same time, as a comparative example, HFC134a
(Comparative Examples A, B, and C) are shown for each of the mixing ratios of 70% by weight and 100% by weight, and for the case of HFC143a alone foaming (Comparative Examples A, B, and C).

[0019]

[Table 1]

As described above, the foamed heat insulating material of the present invention is prepared by adding and mixing HFC143a as a foaming agent component and HFC134a in an amount of 80% by weight or more of the foaming agent component.
It was found that the combustibility of 43a enters the non-combustible region as a foaming agent mixed gas, the combustibility is eliminated, and the combustibility of 43a can be used for production in the same manner as the non-combustible foaming agent without requiring safety measures for fire fighting.

Further, both HFC143a and HFC134a have no influence on the ozone layer depletion, and can be applied as an alternative blowing agent for HCFC, which has a slight ozone layer depletion effect. You can contribute.

Furthermore, since HFC143a has a lower gas thermal conductivity than HFC134a and uses 20% by weight or less of HFC143a as a foaming agent component, the gas thermal conductivity of the mixed gas is that of HFC134a alone. As a result, the foam thermal conductivity is lower than that of the HFC134a foam insulating material alone.

As shown in the comparative example, HFC134
When the mixing amount of a is 70% by weight, the flammability of the mixed gas is not resolved, and safety measures such as explosion-proof equipment are required in mass production. Also, due to the poor compatibility with HFC143a polyol, the floss void As a result, the foam appearance and the foam heat insulation performance deteriorate together, making it difficult to apply.

[0024]

As described above, according to the present invention, 1,1,1-trifluoroethane as an organic polyisocyanate, polyol, water, a catalyst, a foam stabilizer and a blowing agent component and a blowing agent component
A foamed heat insulating material formed by foaming by mixing and stirring 0% by weight or more of 1,1,1,2-tetrafluoroethane.

An outer box, an inner box, and a heat insulating box body obtained by filling the foamed heat insulating material in a space formed by the outer box and the inner box are obtained.
Even when C143a is used as the foaming agent for the foam insulation, 80% by weight or more of the foaming agent component of HFC134a
Since it is used as a mixed foaming agent mixed with and mixed with, the combustibility of the foaming agent is eliminated as it enters the non-combustible region as a gas component.

Therefore, in the manufacturing process of raw materials, mixing, foaming, etc., it is possible to safely manufacture without requiring special fire prevention safety measures such as special fire prevention equipment and explosion proof equipment.

As a result, hydrofluorocarbon having an ozone depletion potential of 0, which is indispensable for protecting the global environment, can be easily applied as a foaming agent for a foamed heat insulating material, and a foamed heat insulating material having good foam heat insulating performance can be obtained. You can do it.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08G 101: 00) C08L 75:04

Claims (2)

[Claims] 1. An organic polyisocyanate, a polyol,
Water, catalysts, foam stabilizers, 1,1,1-trifluoroethane as a blowing agent component, and 80% by weight or more of the blowing agent component 1,1,
A foamed insulation material produced by foaming by mixing and stirring 1,2-tetrafluoroethane. 2. An organic polyisocyanate, a polyol, water, a catalyst, a foam stabilizer, and a foaming agent component, which are foam-filled in an outer box, an inner box, and a space formed by the outer box and the inner box. 1,1,1-trifluoroethane and 8 of blowing agent components
A heat-insulating box made of a foam heat-insulating material produced by foaming by mixing and stirring 0% by weight or more of 1,1,1,2-tetrafluoroethane.