JPS6321691B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates in particular to a method for producing polyurethane polymers for coatings. Conventionally, when producing a polyurethane polymer as a paint using a blocked isocyanate compound, a high-temperature baking treatment was required. Therefore, when painting a thin steel plate, problems such as deformation of the steel plate itself, melting of the solder, and high energy consumption occurred. In order to solve this difficulty, it is strongly desired to lower the dissociation temperature of blocked isocyanate compounds. As a dissociation catalyst that lowers the dissociation temperature, for example, tetra-n-butyl-1,3
-Diacetyloxydistanoxane, tetra-n
-Butyl-1,3-diphenoxydistanoxane, tetra-n-butyl-1,3-dibenzyloxydistanoxane, di-n-butyltin oxide, di-n-butyltin dilaurate, etc. have been proposed. ing. However, even these compounds cannot be said to have sufficient catalytic effects, and even better catalysts are desired. In view of this, the inventors of the present invention have repeatedly investigated the possibilities, and as a result, have discovered that an excellent catalytic effect can be obtained by using a specific monoalkyltin mono(carboxylic acid ester), leading to the present invention. That is, the present invention combines a blocked isocyanate compound and an active hydrogen-containing compound into monobutyltin mono(acetate),
Monobutyltin mono(2-ethylhexanoate),
The reaction is carried out in the presence of a monoalkyltin mono(carboxylic acid ester) selected from monobutyltin mono(maleic acid monoethyl ester), monobutyltin mono(laurate), and monooctyltin mono(2-ethylhexanoate). The present invention relates to a method for producing a characteristic polyurethane polymer. The blocking isocyanate compounds used in the present invention are the addition products of each stoichiometric amount of a polyisocyanate compound and an isocyanate blocking agent. The polyisocyanate compound referred to herein may be any compound, such as tolylene diisocyanate, xylene diisocyanate,
Aromatic, cycloaliphatic, and aliphatic polyisocyanate compounds such as phenylene diisocyanate, bis(isocyanatomethyl)cyclohexane, and tetramethylene diisocyanate, and excess amounts of these polyisocyanate compounds, as well as ethylene glycol, propylene glycol, and trimethylolpropane. Examples include terminal isocyanate-containing compounds obtained by reacting low-molecular active hydrogen-containing compounds such as , hexanetriol, and castor oil. Isocyanate blocking agents include phenols such as phenol, m-cresol, xylenol, and thiophenol, alcohols such as methanol, ethanol, butanol, 2-ethylhexanol, cyclohexanol, and ethylene glycol monomethyl ether, ethyl acetoacetate, and malonic acid. Examples include active hydrogen-containing compounds such as diethyl. On the other hand, the compound serving as the base of the polyurethane polymer is an active hydrogen-containing compound, such as polyether polyol, polyester polyol, polyurethane polyol, and epoxy group-containing polyol. Next, the specific monoalkyltin mono(carboxylic acid ester) used in the present invention can be obtained, for example, by reacting 1 mole of monobutyltin monotrichloride with 2 moles of caustic alkali in an aqueous solvent, and then reacting with an aqueous solution of 1 mole of sodium carboxylate. It can be produced by dropping it dropwise, but it can also be produced by adding an organic solvent to 1 mole of monobutyltin oxide and 1 mole of dibasic acid monoalkyl ester and reacting the mixture while distilling off the refluxing water. These compounds obtained in this way are used as catalysts in the present invention, but the method of the present invention can be used in any application as long as blocked isocyanate compounds are used, such as in cationic electrodeposition paints, powder paints, etc. It can also be applied to the production of polyurethane polymers. For example, in a cationic electrodeposition coating, a reaction product of a blocked isocyanate compound and an active hydrogen-containing compound is made water-soluble and then polymerized in the presence of the organotin compound of the present invention to form a coating film. The larger the amount of organotin compound used as a catalyst, the easier the reaction will proceed at lower temperatures to obtain a polymer.
It is 0.1-5%, preferably 0.1-1%. Also,
There is no problem in mixing antirust pigments, extender pigments, etc. necessary for the paint. The following examples illustrate the invention without limiting it thereto. Production example 1 Production of monobutyltin mono(2-ethylhexanoate) A 500ml 4-necked flask was equipped with a stirrer, a thermometer, a dropping funnel, and an air cooling tube, and 28.2g (0.1 mol) of monobutyltin trichloride and deionized water were added.
After adding 200 ml and bringing the internal temperature to 20 to 30°C, 32 g (0.2 mol) of a 25% caustic soda aqueous solution is gradually added dropwise, and white crystals begin to precipitate. After dropping, stir at the same temperature for 2 hours, then add 100% hexane.
ml, and at the same temperature, a separately prepared reaction aqueous solution of 14.4 g (0.1 mol) of 2-ethylhexanoic acid, 4 g (0.1 mol) of caustic soda, and 100 ml of water was gradually added dropwise. Drop the contents carefully so that the liquid does not become alkaline. After completion of the dropwise addition, the reaction was allowed to proceed for 1 hour, and the hexane layer was separated and concentrated to obtain 30 g of a white film-like substance. Elemental analysis using the chemical formula C ₁₂ H ₂₄ O ₃ Sn showed agreement. C H Sn Calculated value 43.02% 7.17% 35.46% Actual value 43.02% 7.32% 34.94% Production example 2 Production of monobutyltin mono (maleic acid monoethyl ester) Attach a stirrer, thermometer and water separator to a 500ml 4-neck flask to produce monobutyltin monobutyl 50g tin oxide
(0.24 mol), maleic acid monoethyl ester 34.5
g (0.24 mol) and 150 ml of toluene are added, and the reaction is carried out while heating and refluxing and distilling off the sewage water. When toluene is distilled off using about 4 ml of distilled water, 79 g of latex-like material is obtained. Elemental analysis using the chemical formula C ₁₀ H ₁₆ O ₅ Sn showed agreement. C H Sn Calculated value 35.85% 4.78% 35.46% Actual value 35.71% 4.80% 35.13% Example 1 4 with a stirrer, nitrogen inlet tube and thermometer installed
When 146 parts of adipic acid, 41 parts of ethylene glycol, and 89 parts of trimethylolpropane were added to a neck flask and the temperature was gradually raised under a nitrogen stream, 100
Dissolve at °C. Then, when the temperature is gradually raised while stirring, water distills out. While removing this water from the system, the polyester polyol obtained by reacting at 150°C for 2 hours, at 190°C for 3 hours, and then at 190°C for 1 hour under reduced pressure (200 mmHg) was dissolved in ethyl acetate and 50% ethyl acetate was added. Make a solution. This solution 20
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 in 100 parts of this solution.
% of the monobutyltin derivatives listed in Table 1.
0.1 part was added. This was applied to an iron plate and baked in an electric furnace. The results are shown in Table 1.

[Table] Example 2 500 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.) is completely dissolved 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. Cool the residue to 100 °C,
Add 300 parts of butyl acetate. Add tolylene diisocyanate (2,4-tolylene diisocyanate 80% and 2,6-tolylene diisocyanate) to this in advance.
264 parts of a partially blocked diisocyanate prepared by adding 90 parts of ethyl cellosolve dropwise to 174 parts of ethyl cellosolve (mixture with 20%) over 2 hours at 60°C with stirring under a nitrogen atmosphere, and then holding the mixture at 60°C for 2 hours. After dropwise addition over 1 to 1.5 hours at 100°C with stirring, the reaction mixture is maintained at 120°C for 2 hours to react. This is then cooled to 50-60°C and 60 parts of acetic acid and 1550 parts of deionized water are added to obtain a paint base with a solids content of 37% for electrodeposition coating. 100 parts of the 37% paint base produced by the above method, 6 parts of Bengara, 6 parts of titanium white, and the monoalkyltin mono(carboxylic acid) listed in Table 2.
After adding salt and kneading in a ball mill for 20 minutes, diluted with 264 parts of deionized water to obtain a solids content of 13% and a pH of 5.5 to 6.0.
Pigment dispersion composition liquid. This product was used as an electrodeposition bath to electrodeposit on a degreased steel plate (5 x 12 x 0.1 cm) at 50V for 1 minute, then washed with tap water and pre-dried (80℃,
Table 2 shows the results of baking in an electric furnace at various temperatures for 20 minutes.

[Table] (Symbols in the table have the same meaning as in Table 1.)

Claims (1)

[Claims] 1 A blocked isocyanate compound and an active hydrogen-containing compound are combined into monobutyltin mono(acetate),
Monobutyltin mono(2-ethylhexanoate),
The reaction is carried out in the presence of a monoalkyltin mono(carboxylic acid ester) selected from monobutyltin mono(maleic acid monoethyl ester), monobutyltin mono(laurate), and monooctyltin mono(2-ethylhexanoate). A method for producing a characteristic polyurethane polymer.