JPH07179639A - Production of rigid polyurethane foam - Google Patents

Abstract

PURPOSE:To produce a rigid polyurethane foam excellent in thermal conductivity and heat insulation properties without using any substance depletive to the ozonosphere by using a blowing agent comprising water and a specified (hydro) fluorocarbon compound. CONSTITUTION:This production process is one for producing a rigid polyurethane foam by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent, a foam stabilizer and other adjuvants, wherein 0-10 pts.wt., per 100 pts.wt. polyol, water as the blowing agent is previously mixed with the polyol component, 1-10wt.%, based on the total of the polyol component and the polyisocyanate component, a hydrofluorocarbon compound and/or a fluorocarbon compound each having a boiling point of 0 deg.C or below and having an ozone depletion potential of 0 are used as the blowing agent, and 0.02-5 pts. wt., per 100 pts.wt. polyol, a compound (e.g. N,N'-dimethylcyclohexyl-amine) which accelerates the reaction of forming carbon dioxide from water and an isocyanate is used as the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of rigid polyurethane foams and isocyanurate-modified polyurethane foams (hereinafter simply referred to as rigid polyurethane foams), which are mainly used as heat insulating materials or airtightness retaining materials. Regarding the method.

[0002]

2. Description of the Related Art Due to its excellent heat insulation, self-adhesiveness and airtightness, rigid polyurethane foams are used for building structures such as houses and refrigerators, or refrigeration equipment such as vending machines and refrigerators. Widely used as a heat insulating material. This rigid polyurethane foam generally comprises a polyhydroxy compound and a polyisocyanate compound as a catalyst, a foaming agent,
It is produced by mixing and stirring with a foam stabilizer and other auxiliaries, and by physically or chemically generated foaming and curing reaction. And as a foaming agent in this case, it is mainly trichloromonofluoromethane (hereinafter referred to as F-11) because of its advantages of low thermal conductivity and boiling point around room temperature.
Has been used.

However, the adverse effect of the F-11 on the atmospheric environment, such as the destruction of the ozone layer of the earth, has been revealed, and it has been designated as a regulated substance as a specific CFC to reduce the amount used.
Furthermore, the total abolition of use is required. The chlorofluorocarbon represented by F-11 (hereinafter abbreviated as CFC) has a structure containing no hydrogen atom in the molecule, and therefore is chemically stable and is decomposed for the first time in the stratosphere. Are said to destroy the ozone layer. Due to such problems, one or more hydrogen atoms are contained in the molecule, and C
Hydrochlorofluorocarbons (hereinafter abbreviated as HCFC), dichloromonofluoromethane, dichloromonofluoroethane, etc., which are not as chemically stable as FC and therefore weakly affect the destruction of the ozone layer, have been proposed as alternative blowing agents. Although these HCFCs are weak, they are used transiently because they destroy the ozone layer.
It will not be usable in the future.

[0004]

Therefore, a rigid polyurethane foam using a foaming agent which does not destroy the ozone layer at all.
Although the practical application of the system is desired, the technique studied so far is to use only water as a foaming agent and to utilize carbon dioxide gas generated by the reaction between water and a polyisocyanate compound. Generally, the technology that uses only water as a foaming agent does not destroy the ozone layer, but it has the drawback of using water as a foaming agent, which is the poor thermal conductivity of carbon dioxide or carbon dioxide gas There is a problem that the heat insulating property and the dimensional stability are inferior and the adhesive property is deteriorated due to the fact that it is diffused from the inside of the atmosphere into the atmosphere and is easily replaced with air.

Under these circumstances, a technique using a hydrofluorocarbon compound that does not destroy the ozone layer has been proposed in recent years. In this case, water is used as a foaming agent in an appropriate partial amount range. Utilizing the carbon dioxide gas generated in this way is effective in maintaining the spraying workability in the conventionally proposed high-pressure spray foaming and improving the liquid fluidity in the injection foaming.

The present invention has been made in view of the above circumstances, and by using a foaming agent having a low boiling point that does not destroy the ozone layer at all, a hard material having excellent foaming stability, adhesiveness, thermal conductivity and dimensional stability. A polyurethane foam is provided.

[0007]

As a foaming agent, the present inventors have developed a hydrofluorocarbon which does not destroy water and the ozone layer.
When used in combination with a bon compound and / or a fluorocarbon compound (hereinafter referred to as a foaming agent F), a rigid polyurethane foam having excellent thermal conductivity and dimensional stability and having little quality variation. The present invention has been completed by finding out that the above-mentioned problems can be obtained.

That is, the gist of the present invention is polyisocyanate.
In the foaming of a rigid polyurethane foam in which a foaming component is mixed with a catalyst, a foaming agent, a foam stabilizer, and a polyol component mixed with other auxiliaries with a mixing head to foam, water is used as a foaming agent in advance. -0.5 parts per 100 parts by weight.
A hydrofluorocarbon compound and / or a fluorocarbon compound having a boiling point of 0 ° C. or less and an ozone depletion coefficient of zero is mixed as a foaming agent in advance in an amount of 5 to 10 parts by weight. , A polyurethan component and a polyisocyanate component are used together in the range of 1 to 10% by weight based on the total weight, or the foaming agent F is used alone to produce a rigid polyurethane foam. It depends on the method.

[0009]

The polyol which can be used in the present invention is not particularly limited, and is obtained, for example, by ring-opening addition polymerization of alkylene oxide such as ethylene oxide and propylene oxide with glycerin, pentaerythritol, sucrose, ethylenediamine and the like. Polyether polyols and polybasic acids such as adipic acid and succinic acid, and polyhydroxyl compounds such as ethylene glycol and propylene glycol, polycondensation reaction, or ring-opening polymerization of lactones There are polyester polyols,
Each can be used alone, or two or more kinds can be freely used in combination.

If the amount of water used as a foaming agent exceeds 10 parts by weight, adhesiveness will be a problem, but if it is 10 parts by weight or less, the combination with the foaming agent F can be arbitrarily set. The preferred amount used is 0.5 to 5 parts by weight. Further, the foaming agent F used in combination with water has insufficient vaporization power and poor foaming efficiency when the boiling point is 0 ° C. or higher, and the vaporization power is too strong when the boiling point is −70 ° C. or lower, so that stable stirring and mixing should be performed. It is difficult to obtain a foam product of uniform quality. When the amount of the foaming agent-F used is less than 1% by weight, the thermal conductivity is poor,
On the other hand, when it exceeds 15% by weight, the vaporizing force is too strong and the foaming becomes unstable, and the bubbles are coarse, so that a good foam cannot be obtained. Therefore, in the present invention, the amount of the blowing agent-F added is 1 to 10% by weight, preferably 2 to 8% by weight, based on the total weight of polyol and polyisocyanate.

The amounts of water and the blowing agent-F used are selected within the above-mentioned amount ranges according to the design values of foam density and thermal conductivity. What is used as the foaming agent-F is, for example, tetrafluoroethane, pentafluoroethane or the like which does not destroy the ozone layer, and they may be used alone or in combination.

The compound used as a catalyst in the present invention is a compound having an action of accelerating a carbon dioxide generating reaction from at least water and isocyanate, such as N, N ^'.
- ^{dimethylcyclohexylamine, N, N, N 'N} ' N
^'' Pentamethyldiethylenetriamine, bis (2-dimethylaminoethyl) ether, etc., each of which may be used alone or in combination of two or more. The amount of these compounds used is 0.02 to 5 parts by weight, more preferably 0.0 to 5 parts by weight, based on 100 parts by weight of the total polyol.
It is 5 to 3 parts by weight, so that the object of the present invention can be effectively achieved. When the amount of these compounds used is less than 0.02 part by weight, the amount of carbon dioxide gas produced is less than
The effect on foaming efficiency is insufficient. On the other hand, if the amount of use of these compounds exceeds 5 parts by weight, the carbon dioxide gas generation rate is too high to obtain foaming stability, which is not recommended. On the other hand, the catalyst that can be used in combination with these compounds is not particularly limited, and those used in the field of polyurethane foam such as lead octoate can be used as they are, and potassium acetate, potassium octylate, etc. Those used for the isocyanurate modification can also be used.

As the foam stabilizer, any foam stabilizer effective for producing a rigid polyurethane foam can be used. For example, polyoxyalkylene-based ones such as polyoxyalkylene alkyl ether and silicone-based ones such as organopolysiloxane can be used in a usual amount.

Further, in the present invention, any component other than the above, such as a filler, a flame retardant, etc., may be used within the range not impairing the object of the present invention.

The polyisocyanate compound usable in the present invention is diphenylmethane diisocyanate.
, Aromatic diisocyanates such as tolylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate. The class, those crude products, etc. can be used.

Polyisocyanate based on the total amount of polyol
The amount of the isocyanate used, that is, the isocyanate index, is in the range of 80 to 130 in the case of producing a normal rigid urethane foam, and in the range of 150 to 350 in the case of producing an isocyanurate-modified rigid urethane foam. It is desirable to set the range.

From the above raw materials, a rigid polyurethane foam
In-situ foaming, pouring, laminate, and board
It can be applied to any of the above. As an example, the production method of in-situ foaming will be described. An airless mixing type high-pressure spray foaming machine is used to prepare the component A mixed solution shown in Table 1, and this is mixed with polyisocyanate in a mixing head at high pressure. At this time, as a method for mixing the foaming agent F and the other components, a method of directly mixing in the mixing head or a conduit from the other components to the head,
It is possible to employ a pre-mixing or the like in which other components such as a polyhydroxy compound component are mixed in advance before being mixed by a mixing head.

[0018]

EXAMPLES The present invention will be described more specifically below based on Examples and Comparative Examples, but the present invention is not limited to these Examples. According to the formulation shown in Table 1, first, the component A mixture liquid was prepared, and three components of the mixture liquid A, polyisocyanate, and foaming agent F (HFC-134a) were prepared. Next, a gasmer model FF unit (manufactured by Gasmer) was used as an airless mixing type high pressure spray foaming machine system, and a blended liquid A and polyisocyanate were used.
The main components are the main pump, foaming agent-F (HFC-134
a) is pumped from the subunit pump, vertical 910 mm, horizontal 18
A calcium silicate plate having a thickness of 20 mm and a thickness of 5 mm was spray-foamed at room temperature of 20 to 25 ° C. The temperature of the compounding liquid in the foaming machine is set to 40 ° C, and the air pressure of the air pump is 5 kg / cm ^2.
And The hard polyurethane foam was sprayed to a thickness of 20 to 30 mm per layer and laminated 4 to 5 times. The results are shown in the examples.

[0019]

[Comparative Example] Table 1 shows a case where a compound that accelerates a carbon dioxide gas generation reaction from water and isocyanate is not used (Comparative Example 1) and a blowing agent HFC-134a is used at 12% by weight (Comparative Example 2). A hard polyurethane foam was obtained in the same manner as in the example according to the formulation shown in (1).

[0020]

[Table 1]

The following components were used as the ingredients in Table 1. * Polyol A: Asahi Glass Co., Ltd., Polyetherpolyol, product name FD-163 * Polyol B: Asahi Glass Co., Ltd., Polyetherpolyol, product name FD-1370 * Catalyst A: Kao Corporation, triethylenediamine dipropylene glycol 33% solution, trade name Kaolizer-N
o. 31 * Catalyst B: Pentamethyldiethylenetriamine, manufactured by Kao Corporation, trade name: Kaolizer-No. 3 * Catalyst C: Nippon Kagaku Sangyo, Ltd., DO of lead octylate
P solution (Lead concentration 17%) * Flame retardant: Stophar Japan Co., Ltd., Tris monochloropropyl phosphate, trade name PHYOL PC
F * Foam stabilizer: manufactured by Nippon Unicar Co., Ltd., silicone foam stabilizer
Product name L-5420 * Blowing agent: Mitsui Fluorochemical Co., Ltd. HFC-13
4a * Polyisocyanate: Sumitomo Bayer Urethane Co., Ltd., crude diphenylmethane diisocyanate

Further, the foam density, thermal conductivity, adhesiveness, and spray atomization width of each hard polyurethane foam were examined by the following methods, and the results are shown in Table 1. * Form density: Measured according to JIS-A-9514 * Thermal conductivity: Measured according to JIS-A-9514 * Adhesiveness: After spraying, observe the cross section of the foam to see the frame and foam or foam Check for peeling between layers * Spray atomization width: A circular hard urethane trace formed on the calcium silicate plate by spraying with a distance of 1 m from the gun tip of the foaming machine to the calcium silicate plate The diameter of

As a result, a spray fog is used if the blowing agent is water and HFC having a low boiling point which does not destroy the ozone layer, but does not use a compound that accelerates the carbon dioxide production reaction from water and the isocyanate. It can be seen that the workability is inferior because there is a shortage of the formed width, it is difficult to spray the foam with a uniform thickness, and the foam peels off after spraying. Further, when a large amount of a foaming agent having a boiling point of 0 ° C. or less is used as in Comparative Example 2, the foaming stability is insufficient and a good rigid polyurethane foam cannot be obtained. On the other hand, in the examples, a hard polyurethane foam having good workability and excellent physical properties can be obtained by using a compound that accelerates the carbon dioxide gas generation reaction from water and isocyanate.

[0024]

As described above, according to the method for producing a rigid polyurethane foam according to the present invention, the ozone layer, which is strongly demanded by society for the protection of the global environment, is not destroyed and heat is not required. It is also possible to obtain a good rigid polyurethane foam having excellent conductivity and sufficiently satisfying the function as a heat insulating material, and its industrial utility value is extremely high.

Claims (1)

[Claims] 1. When a rigid polyurethane foam is produced by reacting a polyol and a polyisocyanate in the presence of a catalyst, a foaming agent, a foam stabilizer and other auxiliaries, water is previously used as a foaming agent. , 0 to 1 per 100 parts by weight of polyol
A hydrofluorocarbon compound and / or a fluorocarbon compound having a boiling point of 0 ° C. or less and an ozone depletion coefficient of zero was mixed as a foaming agent with 0 parts by weight of a polyol component. -The compound is used in the range of 1 to 10% by weight based on the total weight of the polyol component and the polyisocyanate component, and at least a compound having a function of promoting a carbon dioxide gas generation reaction from water and the isocyanate is used as a catalyst. 0.0 per 100 parts by weight
A method for producing a polyurethane foam, which comprises using 2 to 5 parts by weight.