JPS5923328B2 - Foaming agent composition for polyurethane foaming - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyurethane foam blowing agent compositions suitable for forming stable polyurethane foam premixes containing trichlorofluoromethane, polyols, and the like.

When producing polyurethane foam, a premix for polyurethane foaming is often prepared by mixing a polyol, a foaming agent such as trichlorofluoromethane, a foam stabilizer, a catalyst, etc., and then reacted with isocyanate.

The blowing agent trichlorofluoromethane alone is stable, but the polyol and trichlorofluoromethane coexisting in this premix react with each other during storage to generate hydrogen chloride, aldehydes, ketones, etc., and as a result, the premix Significant problems often arise in which the properties of the material deteriorate.
Specific phenomena of this deterioration include coloring of the premix,
Examples include an increase in viscosity, a decrease in the reaction rate when producing polyurethane foam by mixing the premix with isocyanate, and roughening of the foam. Therefore, improving the storage stability of this premix has been an important challenge in the industry. Many compounds have been proposed as stabilizers for the premix.

For example, certain olefin compounds such as alloocimene, butadiene, isoprene, and styrene, and α-pinene,
Specific terpenes such as β-pinene and α-limonene (see Japanese Patent Publication No. 39-23099);
19393); benzenes having a nuclear-substituted halogen or nitro group (see Japanese Patent Publication Nos. 45-32048 and 45-32049); and ethylene oxide;
Epoxides such as ethyl cellosolve and cellosolves (
JP-A No. 4958199). however,
The results obtained with these compounds are not fully satisfactory from a practical point of view. In view of such conventional circumstances, the present invention has been extensively researched from the point of view of improving the stability of the premix, and has found that extremely excellent effects can be obtained by using specific first and second compounds in combination. The present inventors have discovered that the foaming agent composition for polyurethane foaming of the present invention can be achieved.

That is, the foaming agent composition for polyurethane foaming of the present invention has (
a) Trichlorofluoromethane or a mixture of trichlorofluoromethane and another blowing agent; (b) General formula (however, in the above general formula, R1, R2 and R3 are each hydrogen or a hydrocarbon having 1 to 3 carbon atoms) and (c) a general formula (wherein, in the above general formula, R4 is hydrogen, a hydroxyl group, a halogen, or a compound having 1 to 3 carbon atoms); , R5 represents hydrogen or a hydroxyl group, and R6 and R7 each represent hydrogen or a hydrocarbon group having 1 to 5 carbon atoms. one second compound;

The foaming agent composition for polyurethane foaming of the present invention can be produced by mixing the first and second compounds in a liquid foaming agent.

Furthermore, it is possible to contain a polyol or the like if necessary, and for example, it can be added to a premix for polyurethane foaming in which a blowing agent, a polyol, a foam stabilizer, a catalyst, etc. are mixed in advance. The blowing agent trichlorofluoromethane itself is stable, and the blowing agent composition for polyurethane foaming of the present invention containing the first and second stabilizer compounds is very stable under normal handling of the stabilizer. Needless to say, it is stable for a long time.

By using the foaming agent composition for polyurethane foaming of the present invention, it becomes possible to form an extremely stable premix for polyurethane foaming. General formula, R1-C
Specific examples of the first i compound represented by -CH-R2 include p-methylstyrene, p-ethylstyrene, α-methylstyrene, α-ethylstyrene, and p-methylαmethylstyrene.

Some of these compounds have already been recognized to be effective as stabilizers for the premix. However, as mentioned above, sufficient effects cannot be obtained with this compound alone. Next, as a specific example of the second compound of benzotriazole represented by the general formula, 2(3/・
5' ditertiary butyl 2' hydroxyphenyl) benzotriazole; 2 (2' hydroxy 3' tertiary butyl 51 methyl phenyl) 5 chlorobenzotriazole; 2 (3ζ 5' dimesiary butyl 2' hydroxyphenino(c) 5 chloro Benzotriazole; 2(3
'・5/tertiary amyl 2' hydroxyphenyl)
These include benzotriazole.

However, these compounds alone do not stabilize the premix or have only a slight stabilizing effect. From this fact, these compounds themselves hardly contribute to the stabilization of the premix directly, but rather contribute to the stabilization through the organic bonding effect with the first compound represented by the above general formula. It is assumed that As the blowing agent, trichlorofluoromethane is used alone or trichlorofluoromethane is combined with other blowing agents, such as chlorinated alkanes such as dichlorodifluoromethane, trichlorotrifluoroethane and dichlorotetrafluoroethane; methyl chloride; Mixtures with added chlorinated alkanes such as methylene chloride, ethyl chloride and ethylene chloride can be used.

The amounts of the first compound and the second compound represented by the above general formula are 0.05 to 5% by weight and 0.05% by weight, respectively, based on the blowing agent.
．． 001-0.5% by weight is used. The upper limits of the amounts of the first and second compounds to be used are not limited, and this indicates that if the upper limits are exceeded, no further stabilizing effect can be expected. On the other hand, if the amount is less than the lower limit, a sufficient stabilizing effect cannot be expected. For polyurethane foaming stabilized by the blowing agent composition for polyurethane foaming of the present invention as described above *<<The premix contains only the first or second compound added, as shown in the example below. A very superior stabilizing effect is observed compared to that using a foaming agent composition for polyurethane foaming.

Next, the present invention will be specifically explained with reference to examples.

The method for measuring the acid content in each example and the viscosity in Example 1 is as follows. Acid content: Take 17 of the premix for polyurethane foaming, dilute it with a benzene/isopropanol/water mixture (mixing ratio 500:495:5), and titrate with a 1/10 NK0H isopropanol solution using α-naphtholbenzein as an indicator. Measure minutes.

The acid content is expressed as the weight (y) of KOH required to neutralize the premix 1007. Viscosity: The viscosity of the premix at 20° C. is measured using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. Viscosity is expressed in centiboads (Cp). Example 1 A premix for polyurethane foaming with the above formulation was placed in a glass pin containing a fringe piece, and a storage test was conducted in a constant temperature bath at 50°C.

Table 1 shows the names of the first and second stabilizer compounds, their Wt% relative to the blowing agent, experimental conditions, and experimental results. A premix for polyurethane foaming having the above formulation was placed in a glass pin containing a piece of tinplate, and a storage test was conducted in a constant temperature bath at 50°C.

Claims (1)

[Claims] 1 (a) Trichlorofluoromethane or a mixture of trichlorofluoromethane and another blowing agent; (b) General formula ▲
There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the above general formula, R_1, R_2 and R_
3 represents hydrogen or a hydrocarbon group having 1 to 3 carbon atoms.
and (c) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the above general formula, R_4 is hydrogen, a hydroxyl group, a halogen, or a hydrocarbon group having 1 to 3 carbon atoms. , R_5 represents hydrogen or a hydroxyl group, R
_6 and R_7 are each hydrogen or carbon atoms 1 to 5
A foaming agent composition for polyurethane foaming, comprising: at least one second compound selected from benzotriazoles represented by (representing a hydrocarbon group);