JPS59142219A - Method for manufacturing rigid urethane foam with open cells - Google Patents

Abstract

PURPOSE:To produce a rigid urethane foam which, when used with an inner box made of ABS or the like used in a refrigerator or the like, does not cause cracking, by reacting a specified polyol component with an isocyanate component in the presence of a specified reaction catalyst, a blowing agent, etc. CONSTITUTION:A rigid urethane foam is produced by reacting (A) a polyol component comprising a mixture of triethanolamine polyether and an ethylenediamine polyether with (B) an isocyanate component comprising polymethylenediphenyl diisocyanate in the presence of (C) a reaction catalyst comprising a water-soluble tertiary amine, (D) a blowing agent comprising a mixture of water and trichloromonofluoromethane, (E) a foam stabilizer comprising an organosilicone block copolymer, (F) an open-cell agent comprising glycerin, and (G) a separation stabilizer comprising a phenolic polyether. It is possible to prevent an inner box for a refrigerator or the like from being cracked by clouding at low temperatures. The adhesion to an inner box is improved and the strength of the box is improved.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a method for manufacturing a rigid urethane foam having open cells, and in particular, when AH8 or the like is used as an inner box of a refrigerator, etc., the inner box is damaged by solvent attack. This invention relates to a method for producing an excellent hard urethane foam that prevents whitening cracks from occurring.

[Prior art]

Conventional 100x hard urethane foam with open cells is unstable in forming open cells, and has disadvantages such as separation of the foaming stock solution from the blowing agent, reduced fluidity in the mold, and rough and brittle cells in the formed foam. Therefore, it was not possible to put it into practical use in on-site foaming. This is due to the composition of the foaming stock solution, and as a result of thoroughly reviewing and inspecting the polyol, catalyst, blowing agent, foam stabilizer, open cell agent, etc., we have developed a stock solution formulation that overcomes the two drawbacks. This new discovery has made it possible to apply it to on-site foaming. However, in applications such as refrigerators, when plastics such as ABS are used for the inner box, whitening cracks tend to occur at low temperatures, creating a need for improvement.

[Purpose of the invention]

The object of the present invention is a method for producing rigid urethane foams having open cells. In particular, stabilization of open cells, no separation from the foaming agent in the stock solution, improved foam fluidity,
It has many excellent properties such as fine bubbles and no brittleness, and can prevent whitening of plastic inner boxes such as An8 when used in refrigerators, etc., and has better insulation performance than glass wool, and has a foaming ratio of 100. The purpose of the present invention is to provide a low specific gravity hard urethane foam insulation material.

[Summary of the invention]

As a result of various studies as a means to prevent separation from the foaming agent,
Among polyols, aliphatic amine polyethers are preferred;
In particular, it has been found that a mixing ratio of 75 parts of triethanolamine and 25 parts of ethylenediamine is effective as it can be dissolved in the blowing agent. To further ensure 100 times more foaming, add 1 part of water.
Trichloromonofluoromethane is introduced into this as a necessary condition, but methylene chloride is mixed to prevent oversaturation and separate volumes, or when applied to refrigerators etc. A plastic inner box such as A 13 S etc. It was found that the inner box was susceptible to whitening and cracking due to solvent attack. Therefore, it was discovered that phenolic polyether was effective as a substitute for this, and it was possible to eliminate splitting due to trichloromonofluoromethane supersaturation and to prevent whitening cracks on the inner box.

In addition, weak acidity is effective as an open cell stabilizer, but among them, the addition of chrycerin is the most stable, and since the cell state of the foam can be made finer, the fluidity can be improved and the brittleness can also be improved.

[Embodiments of the invention]

An example of the present invention will be described below with reference to Table 1.

Each month used in the experiment was carried out with the following specifications, and the foaming means was generally the same as that for rigid foams.

0 polyol (IN-liethanolamine type 0 catalyst ()) 10 parts of methylethanolamine (
2)) Diethylenediamine/dipropylene glycol 33% liquid 05 parts Foam stabilizer organic silicone block copolymer (L-5420 manufactured by Nippon Unicar) 15 parts Foaming agent (1) Water 10 parts (2)
) Trichloromonofluoromethane 75-90 parts 0 Separation inhibitor Methylene chloride 15-20 parts Open cell stabilizer Glycerin (1st class reagent) 10-15 parts 0 Isocyanate Polymethylene diphenyl diisocyanate 268 parts 0 Index NC010Il-100 Note: 100 Since the purpose was double foaming, the amount of blowing agent (l'lichloromonofluoromethane) was adjusted accordingly, and the amount of isocyanate was calculated based on the required amount using polyether and water.

Table 1 shows that when based on 75 parts of triethanolamine-based polyether and 25 parts of ethylenediamine-based polyether, when 10 parts of water and 75 to 90 parts of trichloromonofluoromethane were used as blowing agents, open cell stability was achieved. Since it is known that 10 to 15 parts is optimal as an agent, here we will discuss the effects of methylene chloride and phenolic polyether as anti-separation agents, and discuss the specific gravity of the foam, open cell formation, Blowing agent separation, flowability, cell condition, and brittleness were investigated.

In order to achieve foaming 100 times the conventional example, 90 parts of trichloromonofluoromethane is required in addition to 10 parts of water, but in order to avoid supersaturation, methylene chloride is introduced to prevent this.
Although it is necessary to hold only 1 unit and 4 foam items as shown in Table 1, the inner box of AI3'S such as a refrigerator has whitening cracks and cannot be used.

Experimental Examples 1 and 2, Examples 1 and 2 It was found that whitening of the inner box could be prevented by introducing a phenolic polyol instead of methylene chloride. That is, by using a phenolic polyol with interfacial action as a separation preventing agent, and focusing on the fact that supersaturation can be prevented even if the amount of trichloromonofluoromethane is increased accordingly, we attempted to prevent whitening and cracking of the inner box by introducing a phenolic polyether. However, in order to foam 100 times as well as phenolic polyether and to satisfy the foam condition, polyol 1
It was also found that the limit was 5 to 10 parts compared to 0.00 parts.

〔Effect of the invention〕

According to the present invention, the rigid urethane foam having open cells is used as a +4 insulation material for refrigerators, etc., to prevent problems in on-site foaming, especially whitening and cracking of ABS inner boxes at low temperatures.
Adhesion to the inner box is improved, and the strength of the box body is improved.

In addition, the premix is stable, adhesion does not peel, there is little foam leakage, and the injection amount is stable. With these, the foaming ratio is 1. It is possible to increase O0 times, and the cost advantage is large due to the low specific gravity.Furthermore, since the foaming pressure is low, the foam layer can be simplified from the conventional aluminum layer to a veneer layer, etc., and demolding time can be significantly shortened, increasing productivity. 1iJi has a significant contribution to the low dog effect.

Continuation of page 1 0 shots clear person Katsuhiko Goto Tomita, Ohira-machi, Shimoga-gun, Tochigi Prefecture 800 Hitachi, Ltd. Tochigi Kogyo Inside the venue

Claims (1)

[Claims] 1. A method for producing a rigid urethane foam having open cells by reacting a polyol component and an incyanate component in the presence of a reaction catalyst, a blowing agent, a foam stabilizer, an open cell agent, and a separation stabilizer. In particular, a mixture of triethanolamine polyether and ethylenediamine polyether is used as a polyol, a water-soluble tertiary amine is used as a reaction catalyst, water is used as a blowing agent, a mixture of trichloromonofluoromethane, and an organic silicone block copolymer is used as a foam stabilizer. A method for producing a rigid urethane foam having open cells, characterized in that glycerin is used as a coalescence and open cell agent, phenolic polyether is used as a separation preventing agent, and polymethylene diphenyl diisocyanate is used as an isocyanate. 2. For 100 parts of polyol, 75 parts of triethanolamine polyether as polyol, 25 parts of ethylenediamine polyether, 10 parts of water as blowing agent,
Trichloromonofluoromethane -90 parts, glycerin 1
A method for producing a rigid urethane foam having open cells according to claim 1, characterized in that 0 to 15 parts of phenolic polyether and 5 to 10 parts of phenolic polyether are used.