JPH05125212A - Foamed thermal insulator and thermal insulation box obtained by packing foamed thermal insulator - Google Patents

Abstract

PURPOSE:To ensure the quality of a foamed thermal insulator and insulation box for use in, e.g. a refrigerator or freezer and to contribute to the elimination of the environmental problem of the ozone layer depletion by improving the solubility of a low-boiling foaming agent comprising an HCFC or HFC in a polyol ingredient to thereby attain, e.g. a decrease in the thermal conductivity of the foam. CONSTITUTION:An organic polyisocyanate is mixed, under stirring, with a polyol ingredient containing 5-25% hydroxyl compound having a molecular structure of the formula, a foam stabilizer, a catalyst, and a low-boiling foaming agent comprising an HCFC or HFC and having a boiling point of -50 to 0 deg.C. This mixture is foamed to obtain the title insulator. The title box is obtained by introducing the foamable mixture into the space between an inner box and an outer box and causing the mixture to foam and fill the space.

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 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 C
Environmental problems such as ozone depletion and global warming due to the influence of (FC) are attracting attention, and C is used in the production of a rigid urethane foam, which is a typical foam insulation material.
For the purpose of reducing the amount of FC used, a method of using carbon dioxide gas obtained by the reaction of organic polyisocyanate and water as a part of a foaming agent, or an alternative substance of CFC, which has little influence on ozone destruction 2, Various improvement measures such as foaming with 2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-fluoroethane are being studied.

Conventionally, in the production of foams, foaming with trichlorofluoroethane (hereinafter referred to as CFC11) having a boiling point near room temperature or a floss method using dichlorodifluoromethane (hereinafter referred to as CFC12) which is a low boiling point foaming agent, etc. Has been used. By using a low boiling point compound such as CFC12 as a part of the foaming agent, the foaming raw material liquid is discharged in a cream shape from the nozzle of the foaming machine. Therefore, although the flow of the raw material liquid is small, the shape of the bubbles is close to a sphere, and the internal pressure of the gas trapped in the bubbles is high, so that a foam having excellent low-temperature dimensional stability can be obtained.

For example, JP-A-59-38240 discloses low-boiling point blowing agents such as 1-chloro-2,2,2-trifluoroethane, monobrom monochlorodifluoromethane,
It is characterized by using a mixture of at least one compound of trans-1-chloro-2-fluoroethylene in an amount of 2 to 50% by weight with respect to the total foaming agent to produce a foam insulation material. There is.

[0005]

However, as mentioned in Japanese Patent Laid-Open No. 59-38240, in the foaming of the foam by using the above low boiling point foaming agent alone or in a large amount, the inside of the foam is A large number of froth voids are likely to occur, the cells become non-uniform, the closed cell rate deteriorates, and the thermal conductivity of the foam deteriorates. As a factor of these froth voids and cell communication, there is a limit to the compatibility between the low boiling point blowing agent and the polyetherpolyol generally used as a raw material for a rigid urethane foam, and when the amount exceeds a certain level, It is considered that the low boiling point foaming agent dissolved in the raw material cannot be retained and a bumping phenomenon occurs at the moment of discharge, resulting in poor mixing and coalescence of bubbles.

For this reason, as a means for preventing froth voids and communication of bubbles, as shown in JP-A-59-38240, CFC1, which is a foaming agent having a boiling point near room temperature, is used.
There is a method of auxiliary foaming using carbon dioxide gas generated by mixing with 1 or reaction of water and isocyanate, but from the viewpoint of solving global environmental problems and saving energy,
Low boiling point hydrochlorofluorocarbons (hereinafter referred to as HCFCs) and hydrofluorocarbons (hereinafter referred to as HFCs), which have little effect on ozone layer depletion and global warming, are added to conventional high-pressure blowing agents. The problem was to manufacture a high-performance foam insulation material that can be applied without major changes to the foaming machine equipment and that does not have the problem of froth voids.

In view of the above-mentioned problems, the present invention is an excellent foam insulation material which does not have the problem of froth voids or cell communication even when a foaming agent such as HCFC or HFC having a low boiling point which has little influence on global environmental problems is used. It is intended to provide.

[0008]

In order to solve the above problems, the present invention provides an organic polyisocyanate and a polyol component containing at least 5 to 25% of a component having the molecular structure of (Chemical formula 1). , Foam stabilizer, catalyst, and boiling point -50 ° C
A foaming heat insulating material is obtained by mixing and stirring a foaming agent containing HCFC at 0 ° C. or less and at least one component as a component.

The present invention further comprises at least 5 parts of an organic polyisocyanate and a component having a molecular structure of (Chemical formula 1).
A polyol component containing 30%, a foam stabilizer, a catalyst,
A foaming heat insulating material is obtained by mixing and stirring a foaming agent containing HFC having a boiling point of −50 ° C. or higher and 0 ° C. or lower as at least one component.

Further, the foamed heat insulating material is foamed and filled in a space portion constituted by an inner box and an outer box to obtain a heat insulating box body.

[0011]

With the above structure, the compatibility between the hydroxyl component having the molecular structure of (Chemical Formula 1) and the low boiling point blowing agent composed of HCFC or HFC is extremely good, and therefore the solubility with the low boiling point blowing agent is extremely poor. By blending a hydroxyl group component having a molecular structure of (Chemical Formula 1) with a general polyether polyol for hard urethane foam, a low boiling point blowing agent composed of HCFC or HFC as a whole polyol component is obtained. It is possible to produce an excellent foamed heat insulating material which is free of froth voids and no interconnected cells, because it has improved solubility and produces uniform fine cell structure due to uniform foaming behavior.

Furthermore, HFC has an ozone depletion coefficient of 0, and not only does it have no effect on ozone depletion alone, but it also causes ozone depletion even in a mixed system with HCFC, which has some effect on ozone depletion. On the other hand, it is possible to produce an effective foam insulation material.

Further, by filling the foamed heat insulating material to form a heat insulating box, it is possible to secure excellent quality as a heat insulating box without problems such as sweating at a void generation portion and deterioration of heat insulating performance. It is a thing.

As the HCFC foaming agent, chlorodifluoromethane (hereinafter referred to as HCFC22), 2-chloro-1,1,1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane, etc. are used. it can. Further, as an HFC foaming agent, 1,1,1,2-pentafluoroethane (hereinafter referred to as HF
C134a), 1,1,1,2,2, -pentafluoroethane, 1,1-difluoroethane, etc. can be used, but HF
Since the amount of dissolved C is worse than that of HCFC, when HFC is used, a mixed system with HCFC is suitable for improving physical properties such as heat insulation.

[0015]

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

Polyol A is an aromatic amine-based polymer.
Hydroxyl value is 460 mg KOH / g with terpolyol, and hydroxyl value is 1,056 m as a hydroxyl component having a molecular structure of (Chemical formula 1)
gKOH / g diethylene glycol, catalyst is Kaoizer No. 1 manufactured by Kao Corporation, foam stabilizer is silicone surfactant F-335 manufactured by Shin-Etsu Chemical Co., Ltd., blowing agent is water, HCFC22
And HFC134a, each raw material is mixed in a predetermined mixing number to form a premix component. On the other hand, the isocyanate component is a Clude MD having an amine equivalent of 135.
It is an organic polyisocyanate composed of I.

The premix component thus prepared and the isocyanate component are mixed in a predetermined mixing number, foamed by a high-pressure foaming machine, and filled inside a box consisting of an inner box and an outer box,
An insulated box was obtained. In order to evaluate the solubility of the foaming agent at this time, the pressure of the tank filled with the premix, the presence or absence of froth voids, the closed cell rate, the thermal conductivity, and the average cell diameter are shown in (Table 1).

At the same time, as a comparative example, when the hydroxyl group component having the molecular structure of (Chemical formula 1) is not added (Comparative example A)
The case where 35% of diethylene glycol and diethylene glycol are contained in the entire polyol component (Comparative Example B) is shown at the same time (Table 1).

[0019]

[Table 1]

As described above, the foamed heat insulating material of the present invention is HCFC which is a low-boiling-point foaming agent with less problems against ozone destruction.
No. 22 and HFC134a are used, a raw material system that can be stably dissolved in a premix and can be easily foamed even in a conventional high-pressure foaming machine, and a uniform foaming behavior gives a fine and homogeneous cell structure. It was found that an excellent foamed heat insulating material having a high closed cell ratio was obtained. Although the details of this mechanism are unknown, since the ether bond in the molecular structure of the hydroxyl component having the chemical structure of (Chemical formula 1) has a strong affinity for HCFC or HFC, excellent solubility is obtained. It is believed that the use of this as a part of the polyol component improves the solubility of the entire polyol component. As a result, the HCFC or HFC dissolved in the polyol is uniformly foamed, and there is no froth void or bubble breaking phenomenon caused by bumping of the low boiling point blowing agent, and a foamed heat insulating material having excellent heat insulating properties can be obtained. Is.

As described above, the foamed heat insulating material of the present invention contributes to solving environmental problems such as ozone layer depletion by using HCFC or HFC having a low boiling point and a low boiling point as a foaming agent. By using the hydroxyl group component having the molecular structure of) as a part of the polyol component, the raw material solubility can be improved, and various highly adiabatic raw materials that could not be applied due to the extremely poor solubility of the foaming agent can be selected. The excellent heat insulation performance contributes to quality improvement by energy saving.

Further, an HFC having an ozone depletion potential of 0
By using, it is possible to produce an effective foam insulation material against global environmental problems.

The heat-insulating box body filled with the foamed heat-insulating material can ensure excellent quality as a heat-insulating box body without problems such as perspiration at the void generation portion and deterioration of heat insulation performance.

In the comparative example, when the hydroxyl group component having the molecular structure of (Chemical formula 1) was not added (Comparative example A), the low-boiling point blowing agent could not be sufficiently dissolved, and the mixed polyol component was used. The pressure was increased and bumping occurred at the time of discharge, resulting in non-uniform mixing, and it was not possible to form a foamed body due to the generation of froth voids, bubble breakage, and the like.

Further, when 35% of the hydroxyl group component having the molecular structure of (Chemical formula 1) is added to the entire polyol component (Comparative Example B), the low boiling point blowing agent can be sufficiently dissolved. The closed cell ratio was lowered due to the compositional characteristics of the polyol component, resulting in a marked deterioration in the heat insulating performance.

[0026]

As described above, according to the present invention, an organic polyisocyanate, a polyol component containing a hydroxyl component having a molecular structure of (Chemical formula 1), a foam stabilizer, a catalyst, and a boiling point of Since a foaming heat insulating material is produced by mixing and stirring a foaming agent containing HCFC or HFC of 50 ° C or higher and 0 ° C or lower as at least one component, a low boiling point foaming agent composed of HCFC or HFC and a polyol component are combined. It is possible to provide a foamed heat insulating material having improved compatibility, a uniform fine cell structure being generated due to uniform foaming behavior, and excellent physical properties in thermal conductivity. In particular, it is possible to use a general hard polyurethane foam polyether polyol which is effective in reducing the thermal conductivity but has a significantly poor solubility with a low boiling point foaming agent, and the physical properties are remarkably improved. Is something that can be demonstrated.

Furthermore, HFC has an ozone depletion coefficient of 0, and not only does it have no effect on ozone depletion alone, but it also causes ozone depletion in a mixed system with HCFC, which has some effect on ozone depletion. On the other hand, it is possible to produce an effective foam insulation material.

Further, by filling the foamed heat insulating material to form a heat-insulating box, there is no problem of sweating in the void portion or deterioration of heat-insulating performance, and the quality as an excellent heat-insulating box can be secured. This also contributes to the solution of global environmental problems such as ozone layer depletion due to CFC.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08K 5/02 7167-4J F25D 23/06 T 7380-3L // (C08G 18/00 101: 00 ) C08L 75:04

Claims (4)

[Claims] 1. An organic polyisocyanate, a polyol component containing at least 5 to 25% of a hydroxyl group component having a molecular structure of (Chemical formula 1), a foam stabilizer, a catalyst, and a boiling point of −
A foamed heat insulating material produced by foaming by mixing and stirring a foaming agent having at least one component of hydrochlorofluorocarbon at 50 ° C. or higher and 0 ° C. or lower. [Chemical 1] 2. An organic polyisocyanate, a polyol component containing at least 5 to 30% of a hydroxyl component having the molecular structure of (Chemical formula 1), a foam stabilizer, a catalyst, and a boiling point of −
A foamed heat insulating material produced by foaming by mixing and stirring a foaming agent containing hydrofluorocarbon at 50 ° C. or higher and 0 ° C. or lower as at least one component. 3. A heat insulation box body comprising an outer box, an inner box, and the foamed heat insulating material according to claim 1, which is foam-filled in a space formed by the outer box and the inner box. 4. A heat insulating box body comprising an outer box, an inner box, and the foamed heat insulating material according to claim 2, wherein a space formed by the outer box and the inner box is foam-filled.