JPH0770272A - Production of rigid polyurethane foam - Google Patents

Abstract

PURPOSE:To provide a process for the production of a rigid polyurethane foam, capable of producing an excellent foam having peeling resistance between laminated foam layers by using F141b having strong dissolution power and relatively high boiling point, free from environmental problems, having extremely high industrial utilization value and useful mainly as a heat-insulation material, etc. CONSTITUTION:A polyester polyol compound is used as a polyhydroxy compound in the production of a rigid polyurethane foam at a ratio of >=20% in 100 pts.wt. of total polyhydroxy compound. An amine compound having >=2 polymethylene groups and having a dimethylamino group on one terminal is used as a catalyst in an amount of >=e0.02 pts.wt. based on the total polyhydroxy compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rigid polyurethane foam and an isocyanurate-modified polyurethane foam (hereinafter simply referred to as rigid polyurethane foam) which are mainly used as a heat insulating material.

[0002]

2. Description of the Related Art A rigid polyurethane foam is widely used as a heat insulating material for houses, refrigerators and the like because of its good heat insulating property and self-adhesive property. This rigid polyurethane foam is generally produced by mixing and stirring a polyhydroxy compound and a polyisocyanate compound together with a catalyst, a foaming agent, a foam stabilizer and other auxiliaries, and reacting them in the presence of bubbles. ing. Then, as the foaming agent in this case, trichloromonofluoromethane (hereinafter referred to as F ₁₁ ) has been mainly used because of its advantages of low thermal conductivity and boiling point around room temperature.

However, the adverse effect of F _{11 on} the atmospheric environment such as the depletion of the ozone layer of the earth has become clear,
It is required to reduce the amount of substances used as regulated substances and to abolish them. Chlorofluorocarbon represented by F ₁₁ (hereinafter referred to as CFC) has a structure that does not contain hydrogen atom in the molecule and is difficult to decompose because it is chemically stable, and is decomposed for the first time in the stratosphere. The chlorine is said to destroy ozone.

As a method for reducing F ₁₁ , it is common to use water in combination as a foaming agent and utilize carbon dioxide gas generated by the reaction between water and a polyisocyanate compound.
The thermal conductivity of carbon dioxide is relatively high, and further, carbon dioxide diffuses from the inside of the foam into the atmosphere and is easily replaced with air.
Due to poor heat insulation and dimensional stability, all F
Replacing ₁₁ with carbon dioxide is said to be difficult with current technology. Therefore, it has the same effect as F ₁₁ ,
Moreover, it is essential to develop and use substances that do not easily destroy the ozone layer.

As an alternative substance to such CFC, hydrochlorofluorocarbon (hereinafter referred to as HCFC), which contains one or more hydrogen atoms in the molecule, is not as stable as CFC and has a structure that does not easily destroy the ozone layer, Alternatively, development of hydrofluorocarbon (HFC) is progressing, and it is a social demand to manufacture a rigid polyurethane foam using these.

[0006]

In response to such social demands, the boiling point is slightly higher than that of F ₁₁ , but it is relatively hard to destroy the ozone layer in producing a rigid polyurethane foam. For dichloromonofluoroethane (hereinafter referred to as F _141b ) which is an easily usable HCFC, an example using mainly a high pressure spray foaming machine has been conventionally proposed. However, when F _141b is used as a foaming agent, blowing and foaming is performed by this high pressure spray foaming machine, and when laminated to obtain a rigid polyurethane foam having a predetermined thickness, a skin layer formed on the surface and a skin layer formed thereon are sequentially formed. There is a problem that peeling (hereinafter referred to as interlayer peeling) occurs between the spray-laminated foam.

This delamination gradually occurs within a few minutes after the foams have been laminated to a predetermined thickness and the blowing and foaming have been completed. Particularly, the delamination is remarkable in the layer near the central portion in the thickness direction. It has been empirically confirmed to be recognized. Although the reason why this delamination occurs is not clear, the fundamental factor is that F _141b has strong solubility in the polyetherpolyol compound and the polyisocyanate compound. In other words, due to the strong solubility of F _141b, the equilibrium between the resinification reaction rate centered on the reaction between the polyether polyol compound and the polyisocyanate compound and the vaporization / separation rate of F _141b is lost. Presumed to be.

In order to solve these problems, the present inventors have already used a polyester polyol compound in an amount of 30% or more based on 100 parts by weight of the total polyhydroxy compound, so that the internal delamination of the laminated foam is reduced. It has been found that a polyurethane foam can be obtained, and in Japanese Patent Laid-Open No. 125141/1993, the problem that occurs when F _141b or the like is used as a foaming agent is a polyester polyol.
The solution is provided by the use of a ruthenium compound.

However, according to these methods, when foaming is performed using a high pressure spray foaming machine in an environment where the atmosphere temperature of foaming is relatively low (for example, 10 ° C. or lower), spray foaming is performed in order to compensate for the decreasing reaction activity. It has been found that there is a problem in that delamination is likely to occur when the amount of the metal-based catalyst, which is usually an essential catalyst, is increased.

The present invention has been made in view of the above circumstances. Even when F _141B is used as a foaming agent and a metal-based catalyst is _frequently used when the atmosphere temperature at the time of foaming is low, the inside of the laminated foam is It is an object of the present invention to provide a manufacturing method capable of obtaining a hard polyurethane foam with less delamination.

[0011]

Means for Solving the Problems As a result of further intensive studies, the present inventors have used 20% or more of polyester polyol compounds in 100 parts by weight of all polyhydroxy compounds,
By using 0.02 parts by weight or more of an amine compound having two or more polymethylenes having a dimethylamino group at one end in one molecule as a catalyst, based on 100 parts by weight of all polyhydroxy compounds, the atmospheric temperature at the time of foaming can be improved. When the temperature is low, the laminated film is formed even under the condition that the metal-based catalyst is often used.
The inventors of the present invention have found that a foam with less delamination can be obtained inside the film, and have completed the present invention.

[0012]

The polyester polyol compound used in the present invention is a polycondensation reaction of a polybasic acid such as adipic acid, succinic acid and phthalic acid with a polyhydroxyl compound such as ethylene glycol and propylene glycol, Alternatively, they are polyester polyols obtained by ring-opening polymerization of lactones, and can be used alone or in combination of two or more kinds.

The polyester polyol compound is used in an amount of 20% based on 100 parts by weight of the total polyhydroxy compound.
Above, more preferably 30% or more and less than 80%,
Thereby, the object of the present invention can be effectively achieved. When the amount of the polyester polyol compound used is less than 20 parts by weight, the effect for eliminating delamination becomes insufficient. On the other hand, when the amount of the polyester polyol compound used exceeds 80 parts by weight, the reaction activity is reduced, the foam after foaming has an embrittlement phenomenon, and the sagging of the foam during spraying, It is not recommended because it may cause poor adhesion.

On the other hand, the polyhydroxy compound which can be used in combination with the polyester polyol compound is not particularly limited, and examples thereof include glycerin and sucrose.
, Ethylenediamine, and the like, there are polyethylene oxides, etc., and polyetherpolyols obtained by ring-opening addition polymerization of alkylene oxides such as propylene oxide.
Each of them can be used alone or in combination of two or more kinds, but when the reaction activity of the polyester polyol compound is low, it is desirable to use a polyol having a high reaction activity in combination also to supplement it.

The amine compound used as a catalyst in the present invention is an amine compound having two or more polymethylenes having a dimethylamino group at one end as one molecule.
For example, bis (dimethylaminoethyl) ether, N,
N ′, N ″ -tris (diaminopropyl) hexahydro-S-triazine, N, N, N ′, N ′, N ″ -pentamethyldiethylenetriamine and the like, which may be used alone or in combination of two or more kinds. it can. still,
The amount of these amine compounds used is 0.02 parts by weight or more, and more preferably 0.1 parts by weight or more, based on 100 parts by weight of all polyhydroxy compounds, thereby effectively achieving the object of the present invention. be able to. If the amount of the amine compound used is less than 0.02 part by weight, the effect for eliminating delamination becomes insufficient.

On the other hand, the catalyst which can be used in combination with these amine compounds is not particularly limited, and amine compounds such as triethylenediamine and dimethylcyclohexylamine, dibutyltin dilaurate and lead octoate.
Those used in the field of polyurethane foams such as organometallic compounds such as glutamine and stanna octoate are used as they are, and those used for isocyanurate modification such as potassium acetate and potassium octylate. Available.

The amount of dichloromonofluoroethane used as a foaming agent is arbitrarily determined by the density of the desired foam, but is usually 10 to 80 parts by weight, especially 20 parts by weight based on 100 parts by weight of the total polyhydroxy compound. ˜70 parts by weight is desirable. If necessary, water or HCF other than F _141b may be used.
One or more foaming agents of C or HFCs, hydrochlorocarbons such as methylene chloride, etc. can be used.
In this case, the amount of the foaming agent to be used in combination can be arbitrarily selected from 0 to 80 parts by weight with respect to 100 parts by weight of the total polyhydroxy compound, but a low boiling point such as F-22 and F-134. When HCFC or HFC is used in combination, a very small amount such as 0 to 5 parts by weight may be used.
_It is possible to use a simple method such as adding it to the compounding stock solution in the form of mixed freon mixed with _141b , or directly adding it to the component stock solution as the third component.

Further, polyisocyanate which can be used in the present invention.
Examples of the compound include diphenylmethane diisocyanate
, Aromatic diisocyanates such as tolylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate. Classes and their crude products can be used. The amount of the polyisocyanate compound to be used relative to the total amount of the polyhydroxy compound and the compound having other active hydrogen such as water, that is, the isocyanate index is in the range of 80 to 130 in the case of producing a usual rigid polyurethane foam, and isocyanurate. In the case of producing a modified hard polyurethane foam, the range of 150 to 350 is desirable.

As the foam stabilizer, a hard polyurethane foam is used.
Anything effective for the production of aluminum 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, optional components other than the above, such as flame retardants and fillers, may be used within the range not impeding the object of the present invention. When manufacturing a rigid polyurethane foam from the above raw materials, an airless mixing type high pressure spray foaming machine or the like is usually used.

[0021]

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. The following examples 1 to 1 according to the method
5, the hard polyurethane foams of Comparative Examples 1 to 6 were manufactured. Table 1 shows the compounding components and test results of each example.

(Examples 1 to 5) According to the compounding recipe shown in Table 1, first, two components of compounding liquid A and polyisocyanate were prepared. Next, airless mixing type high pressure spray
Using a Gasmer model FF unit (manufactured by Gasmer) as a foaming machine system, the compounding liquid A and the polyisocyanate were pressure-fed from the main pump, and the length was 910 mm and the width was 1800.
mm, 5 mm thick calcium silicate board 5-10 ° C
Spray-foamed at room temperature. The temperature of the blended liquid in the foaming machine was set to 40 ° C, and the air pressure of the air pump was 5 kg.
/ Cm ² . The hard polyurethane foam was laminated 4 to 5 times with a thickness of about 20 to 30 mm.

(Comparative Examples 1 to 6) When the polyester polyol compound used is less than 20 parts by weight and 0.02 parts by weight or more of the amine compound (catalyst B, C) is used (Comparative Example 1), the amine compound is used. When no compound (catalyst B, C) is used (Comparative Example 2), the amount of the polyester polyol compound used is 20 parts by weight or more and the amine compound (catalyst B, C) is used.
Formulations shown in Table 1 in the case of not using any of the compounds (Comparative Examples 3 to 4) and in the case of using the amine compounds (catalysts B and C) but less than 0.02 parts by weight (Comparative Examples 5 to 6). A rigid polyurethane foam was obtained in the same manner as in the examples.

The following components were used as the compounding ingredients in Table 1. * Polyol A: Takeda Yakuhin Co., Ltd., Polyester Polyol GR-07 * Polyol B: Toho Rika Co., Ltd., Polyester Polyol PL-402 * Flame Retardant: Stoffa Japan (Co., Ltd.) ), Pyrrole PCF * Foam stabilizer: manufactured by Nippon Unicar Co., Ltd., Silicone foam stabilizer L
-5420 * Dichloromonofluoroethane: Daikin Industries, Ltd., Daiflon 141b * Metal catalyst: Nippon Kagaku Sangyo Co., Ltd., lead octylate D.I. O. P solution. Lead concentration 17% * Amine-based catalyst A: 33% solution of triethylenediamine in dipropylene glycol manufactured by Kao Corporation (Kaolizer)
No. 31) * Amine-based catalyst B: manufactured by Kao Corporation, trisdimethylaminopropylhexahydro-S-triazine (Kaolizer-No.14) * Amine-based catalyst C: manufactured by Kao Corporation, N, N, N ',
N ′, N ″ -pentamethyldiethylenetriamine (Kaolizer No. 3) * Polyisocyanate: Sumitomo Bayer Urethane Co., Ltd., crude diphenylmethane diisocyanate

[0025]

[Table 1]

In Table 1, the evaluation of delamination is as follows. a: No delamination is observed on the cross section of the laminated form b ... Small delamination with a length of about 10 mm that does not affect practical use is slightly observed between the layers on the cross section of the laminated form c ...... 10-100 mm length between layers of laminated foam cross section
Some degree of peeling is observed d .... Peeling is observed over almost the entire laminated portion between layers in the cross section of the laminated form.

In addition, the foam of each rigid polyurethane foam
The density, thermal conductivity, and the presence / absence of delamination 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 * Existence of delamination: Visual observation of the inside of the obtained foam.

As a result, dichloromonofluoroethane was used, and the polyester polyol compound was used in combination with the metal catalyst in an amount necessary and sufficient to obtain an appropriate reaction activity with respect to the ambient temperature during foaming. Those in which the amine compounds (catalysts B and C) are used in combination (Examples 1 to 5) are
A polyester polyol compound is used in an amount of less than 20 parts by weight (Comparative Examples 1 and 2), and a polyester polyol compound is used in an amount of 20 parts by weight or more, but no amine compound (catalyst B or C) is used. Those not used in combination (Comparative Example 3 to
4) or an amine compound (catalyst B, C) used in combination with less than 0.02 parts by weight (Comparative Examples 5 to 5).
It was found that an excellent hard polyurethane foam without delamination inside the foam was obtained as compared with 6).

[0029]

As described above, according to the method for producing a rigid polyurethane foam of the present invention, the dissolving power is strong,
Further, by using F _141b having a relatively high boiling point, it is possible to obtain an excellent rigid polyurethane foam with less peeling between the laminated foam layers, and there is no environmental defect.
Its industrial utility value is extremely high.

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Claims (1)

[Claims] 1. A method for producing a rigid polyurethane foam by reacting a polyhydroxy compound and a polyisocyanate compound in the presence of a foaming agent containing dichloromonofluoroethane, a catalyst, a foam stabilizer and other auxiliaries. A polyester polyol compound is used as a polyhydroxy compound in an amount of 20% or more based on 100 parts by weight of all polyhydroxy compounds, and an amine compound having two or more polymethylenes having a dimethylamino group at one end as a catalyst is used as a catalyst. 0.0 per 100 parts by weight of all polyhydroxy compounds
A method for producing a rigid polyurethane foam, which comprises using 2 parts by weight or more.