JPH01301729A - Expanded heat insulating material - Google Patents

Abstract

PURPOSE:To obtain the title insulating material useful for refrigerators, etc., having low thermal conductivity of gas and excellent heat insulating properties, comprising a resin composition consisting of specific components, foam stabilizer, a specific catalytic component and dibromodifluoromethane as a blowing agent. CONSTITUTION:The aimed expanded heat insulating material comprising (A) a resin composition consisting of an organic polyisocyanate, liquid phenol of benzyl ether type as a polyol component and polyether polyol containing o- tolylenediamine as an initiator, (B) a foam stabilizer, (C) at least dimethylpiperazine and dibutyl dilaurate as a catalytic component and (D) dibromodifluoromethane as a blowing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a foamed heat insulating material such as phenol urethane foam used as a heat insulating material for refrigerators, freezers, etc.

BACKGROUND OF THE INVENTION In recent years, from the viewpoint of energy conservation, there has been a strong desire to reduce the thermal conductivity of foamed heat insulating materials and improve their heat insulating properties.

Conventionally, in enol urethane foams with excellent heat insulation performance, the compatibility of the benzyl ether type liquid phenolic resin composition as a raw material with the fluorine-containing halogen hydrocarbon blowing agent has been investigated. We have improved the heat insulation performance by uniformly dispersing the raw materials to make the cells of the foam more uniform, and by reducing the amount of carbon dioxide produced by the foam by lowering the water content. For example, as shown in JP-A No. 62-241914, a benzyl ether type liquid phenolic resin composition obtained by blending specific esters was discovered in order to improve the compatibility with a blowing agent. It is proposed to use raw materials. Generally, in order to improve the thermal conductivity of a foam, it is necessary to take measures against resin solid heat conduction heat transfer, radiation heat transfer, and gas heat conduction heat transfer. Regarding the contribution rate of each heat transfer factor, resin solid heat conduction accounts for about 15%, radiation accounts for about 15%, and the remaining about 70% is due to gas heat conduction. The said publication is
It aims at making bubbles more uniform and finer by improving compatibility, and is characterized by being invented with a focus on reducing radiant heat transfer.

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Problems to be Solved by the Invention However, as shown above, radiation heat transfer accounts for about 15% of the total
Furthermore, even if the water content is set to Q, the reduction in carbon dioxide gas is insignificant, so the thermal conductivity of the phenol urethane foam can be significantly increased by making the bubbles finer and reducing the water content. It can be predicted that improvements will be made and energy conservation will be promoted. Therefore, it was a challenge to find a more effective means for improving thermal conductivity of phenol urethane foam, which has excellent heat insulation performance.

Generally, in order to improve the thermal conductivity of a foam, it is necessary to take measures against resin solid heat conduction heat transfer, radiation heat transfer, and gas heat conduction heat transfer. The contribution rate of each heat transfer factor is
Resin solid heat conduction is approximately 15 units.

Radiation accounts for approximately 15%, and the remaining approximately 70% is due to gas heat conduction. The above conventional example mainly reduces radiant heat transfer by making the cells finer.

The present invention focuses on gas thermal conductivity, which accounts for about 70 coefficients of the heat transfer factor, and improves the heat insulation performance of a heat insulating material.

Means for Solving the Problems In order to solve the above problems, the present invention focuses on reducing gas heat conduction, and uses benzyl ether type liquid phenol and orl as organic polyisocyanate and polyol components.
- A resin composition comprising a polyether polyol using lylene diamine as an initiator.

A foamed heat insulating material is obtained by foaming using dimethylpiperazine and dibutine dilaurate as a foam stabilizer and catalyst components, and dibromodifluoromethane as a foaming agent.

Function Generally speaking, the thermal conductivity of gases is characterized by decreasing as the molecular weight increases. However, the increase in molecular weight raises the boiling point, which inhibits foaming and makes it difficult to use as a foaming agent. However, although dibromodifluoromethane has a larger molecular weight than Freon 11, its boiling point is not high at 25° C., which is almost the same as Freon 11, due to the characteristics of a bromine compound. The above configuration in which such dibromodifluoromethane is applied as a 5,,-2 blowing agent reduces the thermal conductivity of the gas, improves the insulation performance of the foam, and does not increase the raw material temperature or the jig temperature. Manufacture is possible under simple foaming conditions. In addition, dibromodifluoromethane has strong polarity and extremely high compatibility with resins.
Even a benzyl ether type liquid phenol resin composition which inherently has insufficient compatibility can be dissolved without any problem, and by improving the compatibility, the cells can be made finer.

Furthermore, by adding an aromatic amine-based polyether polyol, the resin solubility caused by dibromodifluoromethane can be suppressed, and the foam strength is maintained.

Unfortunately, dimethylpiperazine, which is used as a catalyst component, improves the surface hardness of benzyl ether-type liquid phenol, and dibutyltin dilaurate is a strong catalyst for polyether polyols, but it is a strong catalyst for benzyl ether-type liquid phenol. It is a weak catalyst for benzyl ether type liquid 6.

When the reaction between phenol and incyane-1 is inhibited, the reaction between the polyether and the polyether is immediately promoted and the surface hardness of the entire foam is improved.

In this way, by using dibromodifluoromethane as a foaming agent, the insulation performance of the foam can be significantly improved, quality stability can be ensured, and foam insulation materials with excellent mass production can be provided. .

Example EXAMPLES Hereinafter, the foamed heat insulating material of the present invention will be explained with reference to Examples.

The raw material formulation is shown in the table below.

In the table, polyol A is a benzyl ether type liquid phenol resin composition, and has a hydroxyl value of 420 mgKO.
H/g, 7x norpolyol with water content less than 0.3%,
Polyol B is ol--) 1) A polyether polyone with a hydroxyl value of 450 mp KOH/g obtained by addition polymerization of propylene oxide using diamine as an initiator.The foam stabilizer is Shin-Etsu Chemical F-338, catalyst A is dimethylpiperazine, catalyst B is dibutyltin dilaure = 1.
, Catalyst C is Kao Eggplant 1 (TMHDA). Organic polyisocyanate 1-A is Crude MDI manufactured by Mitsui Roto Sotsurethane. The blowing agent A was dibromodifluoromethane, and the blowing agent B was Freon-11.

Various combinations of these raw materials were foamed using a high-pressure foaming machine.
A, -AC are shown in the table. The foaming conditions at this time were a raw material temperature of 20°C and a jig temperature of 40°C. The density, cell diameter, and thermal conductivity of these phenol urethane foams are also shown in the same table. The thermal conductivity is determined by -Mat manufactured by Shinku Riko ■.
Measurements were made using IC at an average temperature of 24°C.

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As is clear from the table, the phenol urethane foam of the present invention was found to exhibit excellent heat insulation performance. this is,
This shows that the thermal conductivity of the foam was improved because the gas thermal conductivity was reduced. In addition, the improvement in compatibility with dibromodifluoromethane resulted in finer bubble diameters and a reduction in radiant heat transfer, resulting in better insulation improvement. In addition, the boiling point of dibromodifluoromethane is 25°C, which is room temperature, and the foaming conditions include controlling the liquid temperature of the raw material and preheating temperature of the insulating box, etc.
Foaming was possible without any problems. This means that dibromodifluoromethane has a molecular weight of 210 and a Freon 11 of 137.
It has a large molecular weight and low gas thermal conductivity compared to bromine compounds, and also has the unique characteristic of a bromine compound that its boiling point is low even when its molecular weight increases. The properties and foaming mechanism of this compound are unknown, and elucidation is a challenge for the future.

Even if the molecular weight increases in this way, the boiling point remains in the room temperature range like Freon 11, so it is industrialized for foaming.

Because it is easy to apply and has strong polarity, it increases the compatibility of the benzyl ether type liquid phenolic resin composition to realize fine bubbles, and lowers the gas thermal conductivity of dibromodifluoromethane itself. The foam's thermal insulation performance was improved due to its low temperature and reduced radiant heat transfer.

Further, by adding the aromatic amine polyether polyol, the resin solubility caused by dibromodifluoromethane is suppressed, and the foam strength can be maintained even stronger.

However, dimethylpiperazine, which is used as a catalyst component, can improve the surface hardness of benzyl ether type liquid phenol, and dibutyltin dilaurate is a strong catalyst for polyether polyols, but it is not effective for benzyl ether type liquid phenol. On the other hand, it is a weak catalyst and promotes the reaction of polyether without inhibiting the reaction between benzyl ether type liquid phenol and incyanate, improving the surface hardness of the entire foam, resulting in an excellent foam.

11 Beano As shown in the comparative example, it was found that when Freon 11 was used as a foaming agent, the gas thermal conductivity increased and the bubbles became coarser, so that the effect of improving the thermal conductivity of the foam was poor.

Effects of the Invention As is clear from the above description, the present invention provides the following effects. That is, the foamed heat insulating material of the present invention has a low gas thermal conductivity and has extremely excellent heat insulating performance due to radiant heat transfer due to the miniaturization of the cells. Further, the dibromodifluoromethane used has a boiling point of 26° C., which is in the normal temperature range, and it is easy to adjust foaming conditions such as liquid temperature and mold temperature, and mass productivity is good. Foamed insulation, which has excellent productivity and greatly improves insulation performance, contributes to energy savings and makes it possible to significantly improve quality.

Claims (1)

[Claims] A resin composition consisting of an organic polyisocyanate, a polyether polyol having benzyl ether type liquid phenol as a polyol component and an ortho-tolylene diamine as an initiator, a foam stabilizer, and at least dimethylpiperazi and dibutyltin dilaurate as catalyst components. , a foam insulation material consisting of dibromodifluoromethane as a blowing agent.