JPS6134728B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyurethane polymer for coatings. Conventionally, high-temperature baking treatment has been required in order to produce a polyurethane polymer by reacting a blocked isocyanate compound with an active hydrogen-containing compound. Therefore, when painting a thin steel plate, problems such as deformation of the steel plate itself and melting of the solder arose. In order to solve this problem, there is a need for a catalyst that lowers the melting temperature of blocked isocyanate compounds. As such a catalyst, the special public
Tetra-n-butyl-1, which is described in JP-A No. 18877, JP-A No. 53-138434, JP-A No. 53-138435, etc.
3-Diacetyloxydistanoxane, tetra-
n-Butyl-1,3-diphenoxydistanoxane, tetra-n-butyl-1,3-dipenzyloxydistanoxane, di-n-butyltin oxide, di-n-butyltin laurate, tetra -n-
Organotin compounds such as butyltin are known. However, even these compounds cannot be said to have sufficient effects, and even better catalysts are desired. In view of this point, the present inventors have made extensive studies and have found that monoalkyltin oxide and monoaryltin oxide have excellent catalytic effects. Furthermore, the present inventors have discovered that even more excellent effects can be obtained by using these compounds in combination with conventionally used dialkyltin compounds and diaryltin compounds, leading to the completion of the present invention. That is, the present invention comprises a blocked isocyanate compound and an active hydrogen-containing compound in the presence of a compound selected from monoalkyltin oxide and monoaryltin oxide, or in combination with a compound selected from dialkyltin compounds and diaryltin compounds. The present invention relates to a method for producing a polyurethane polymer, which is characterized by a reaction. The blocked isocyanate compounds used in the present invention are fully blocked isocyanate compounds and semi-blocked isocyanate compounds, and are produced by conventional methods. A completely blocked isocyanate compound is an excess amount of an aromatic, aliphatic, or alicyclic diisocyanate such as tolylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, or bis(isocyanomethyl)cyclohexane, and ethylene glycol, propylene glycol, It is obtained by reacting an isocyanate blocking agent with a terminal isocyanate-containing compound obtained by reacting a low-molecular active hydrogen compound such as trimethylolpropane, hexanetriol, or castor oil. Examples of isocyanate blocking agents include phenols such as phenol, m-cresol, xylenol, and thiophenol, methanol, ethanol, butanol, 2-ethylhexanol,
Examples include alcohols such as cyclohexanol, and active hydrogen compounds such as ethyl acetoacetate and diethyl malonate. The semi-blocked isocyanate compound is obtained by reacting the above-mentioned diisocyanate and monohydric alcohol in a ratio of 1:1. Examples of the monohydric alcohol include butanol, 2-ethylhexanol, cyclohexanol, and ethylene glycol monomethyl ether. Semi-blocked isocyanate compounds are generally used by making a resin obtained by reacting with a nitrogen-containing active hydrogen compound and neutralizing it with a fatty acid or the like as a cation to make it water-soluble. Furthermore, examples of the active hydrogen compound include polyether polyols, polyester polyols, polyurethane polyols, and epoxy-containing polyols. The monoalkyltin oxide and monoaryltin oxide of the present invention generally include monomethyltin oxide, monoethyltin oxide, monopropyltin oxide, monobutyltin oxide, monooctyltin oxide, monophenyltin oxide, etc., but are not particularly limited to these. It's not something you can do. In addition, examples of dialkyltin compounds and diaryltin compounds that can be used in combination with these monoalkyltin oxides and monoaryltin oxides include tetra-n-butyl-1,3-diacetyloxydistanoxane, tetra-n-butyl-1, 3-diphenoxydistanoxane, tetra-n-butyl-
1,3-dibenzyloxydistanoxane, di-
Examples include n-butyltin oxide, di-n-butyltin dilaurate, diphenyltin oxide, but are not particularly limited to these. The mixing ratio of monoalkyltin oxide, monoaryltin oxide and these dialkyltin compounds and diaryltin compounds may be arbitrary, but in general, monoalkyltin oxide and monoaryltin oxide are mixed with dialkyltin compounds and diaryltin compounds. 10-30% relative to the compound. The mixture is not limited to two types, and two or more types may be mixed if necessary. The larger the amount of the tin compound used as a catalyst in the present invention, the more the reaction proceeds at a lower temperature and a polymer is obtained.
5%, preferably 0.1-1%. Further, there is no problem in mixing antirust pigments, extender pigments, etc. necessary for the paint. According to the present invention, the reaction between the blocked isocyanate and the active hydrogen-containing compound can be carried out at a lower temperature than before.
It is not only easy to proceed and economical, but also
The performance of the coating film is also excellent. Hereinafter, the present invention will be specifically explained with reference to Examples. Example 1 4 equipped with a stirrer, nitrogen inlet tube and thermometer
Adding 146 parts of adipic acid, 41 parts of ethylene glycol, and 89 parts of trimethylolpropane to a neck flask and gradually raising the temperature under a nitrogen stream resulted in 100 parts of adipic acid.
Dissolve at °C. Then, when the temperature is gradually raised while stirring, water distills out. While removing this water from the system, react at 150°C for 2 hours, at 190°C for 3 hours, and then under reduced pressure of 200 mmHg for 1 hour at 190°C. Dissolve the obtained polyester polyol in ethyl acetate and make a 50% ethyl acetate solution. make. To 20 parts of this solution, 17 parts of a 70% methyl cellosolve solution of a completely blocked isocyanate compound prepared from tolylene diisocyanate and 2-ethylhexanol and 20 parts of toluene were added and dissolved. monoalkyl tin oxide,
0.1 part of monoaryltin oxide was added. This was applied to an iron plate and baked in an electric furnace.
Shown in the table.

[Table] Example 2 Monobutyltin oxide was used as the monoalkyltin oxide in the same manner as in Example 1, and di-n-butyltin oxide, di-n-butyltin dilaurate or tetra-n-butyl-1 was used as the monoalkyltin oxide. ，
Table 2 shows the results of coating and baking an iron plate in combination with 3-diacetyloxydistanoxane as shown in Table 2.

【table】

[Table] Example 3 Completely dissolve 500 parts of a condensed epoxy resin of epichlorohydrin and bisphenol A having an epoxy equivalent of 500 (trade name Epon 1001, manufactured by Ciel Chemical Co., Ltd.) in 100 parts of toluene at 80 to 100°C. . Add diethylamine at 80-100℃ while stirring.
Drop 73 parts. After addition, the mixture is heated at 120° C. for 2 hours with stirring. Thereafter, 280 parts of a fatty acid mixture from dehydrated castor oil was added and heated under reflux at 200°C for 5 hours to distill off the produced water, and then toluene was distilled off under reduced pressure. The residue is cooled to 100°C and 300 parts of butyl acetate are added. Add ethyl cellosolve to this in advance to 174 parts of tolylene diisocyanate (a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate).
264 parts of a partially blocked diisocyanate prepared by dropping 90 parts of diisocyanate under a nitrogen atmosphere at 60°C for 2 hours with stirring and then holding at 60°C for 2 hours was added at 100°C for 1 to 1.5 hours while stirring. After dropping, the reaction mixture was kept at 120°C for 2 hours to react.
Next, after cooling this to 50-60℃, 60 parts of acetic acid and 1550 parts of deionized water were added, and the solid content for electrodeposition coating was 37%.
Get % paint base. 37 manufactured by the above method
% paint base, 6 parts of Bengara, 6 parts of titanium white, and the organotin compound listed in Table 3 were added, kneaded in a ball mill for 20 minutes, and then diluted with 264 parts of deionized water to obtain a solid content of 13%. A pigment dispersion composition having a pH of 5.5 to 6.0 is prepared. Use this as an electrodeposition bath on a degreased steel plate (5×
Table 3 shows the results of electrodeposition at 50V for 1 minute on a 12×0.1cm), washed with tap water, pre-dried (80℃, 10 minutes), and baked in an electric furnace at various temperatures for 20 minutes. .

【table】

Claims (1)

[Claims] 1. Reacting a blocked isocyanate compound and an active hydrogen-containing compound in the presence of a compound selected from monoalkyltin oxides and monoaryltin oxides, or in combination with a compound selected from dialkyltin compounds and diaryltin compounds. A method for producing a polyurethane polymer characterized by: