JPH0125771B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyurethane polymers, especially 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 solder, and high energy consumption have arisen. In order to solve this problem, as a dissociation catalyst that lowers the dissociation temperature of blocked isocyanate compounds, for example, Japanese Patent Publication No. 44-18877,
JP-A No. 52-42528, No. 53-138434, No. 53-
No. 138435 etc., tetrabutyl-1,3-diacetyloxydistanoxane, tetrabutyl-
1,3-diphenoxydistanoxane, tetrabutyl-1,3-dibenzyloxydistanoxane, dibutyltin oxide, dibutyltin dilaurate, tetrabutyltin, and the like have been proposed. However, even these compounds cannot be said to have sufficient catalytic effects, and even better catalysts are desired. In view of this point, the present inventors have made extensive studies and found that at least one compound selected from the group consisting of dialkyltin compounds, diaryltin compounds, monoalkyltin compounds, and monoaryltin compounds; It was discovered that when 4'-dimethyl-2,2'-dipyridyl or 2,4,6-tris(dimethylaminomethyl)phenol is used in combination, a much better catalytic effect appears compared to the use of organotin compounds alone. , led to the present invention. That is, the present invention combines a blocked isocyanate compound and an active hydrogen-containing compound with at least one compound selected from the group consisting of dialkyltin compounds, diaryltin compounds, monoalkyltin compounds, and monoaryltin compounds. The present invention relates to a method for producing a polyurethane polymer, characterized in that the reaction is carried out in the presence of 4'-dimethyl-2,2'-dipyridyl or 2,4,6-tolyl(dimethylaminomethyl)phenol. 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 mentioned herein may be of any type, and includes, for example, aromatic, alicyclic, and aliphatic polyesters such as tolylene diisocyanate, xylene diisocyanate, phenylene diisocyanate, bis(isocyanate methyl)cyclohexane, and tetramethylene diisocyanate. Examples include terminal isocyanate-containing compounds obtained by reacting isocyanate compounds and excess amounts of these polyisocyanate compounds with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, and castor oil. Examples of isocyanate blocking agents include phenols such as phenol, m-cresol, xylenol, and thiophenol; alcohols such as methanol, ethanol, butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether; Examples include active hydrogen-containing compounds such as ethyl acetoacetate and diethyl malonate. 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, as dialkyltin compounds, diaryltin compounds, monoalkyltin compounds and monoaryltin compounds used in the present invention, dimethyltin oxide, diethyltin oxide, dibutyltin oxide, dioctyltin oxide, diphenyltin oxide, dimethyltin oxide, etc. Sulfide, diprobyltin sulfide, dibutyltin sulfide, dioctyltin sulfide, dimethyltin diacetate, dimethyltin dibutyrate, dimethyltin dioctoate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin distearate, tetra-n-butyl -1,3-diacetoxydistanoxane, tetrabutyl-1,3-diphenoxydistanoxane, tetrabutyl-1,3-dilauroyloxydistanoxane, tetrabutyl-1,3-diacetoxythiodistannoxane, Tetramethyl-1,
3-di-2-ethylhexylcarbonylthiodistannoxane, dioctyltin diacetate, dioctyltin diacetate, dioctyltin dioctoate, dioctyltin dilaurate, diphenyltin diacetate, diphenyltin dilaurate, monomethyltin oxide, monobutyltin oxide, monooctyl Tin oxide, monophenyltin oxide, monomethyltin monoacetate, monomethyltin monooctoate, monobutyltin monoacetate, monobutyltin monooctoate, monobutyltin monolaurate, monooctyltin monoacetate, monooctyltin monolaurate, monophenyltin Monoacetate, monomethyltin trilaurate, monobutyltin triacetate, monobutyltin trioctoate, monobutyltin trilaurate, monobutyltin tristearate, monooctyltin triacetate, monooctyltin trilaurate, monophenyltin triacetate, monophenyltin trioctoate, monophenyltin trilaurate These include, but are not particularly limited to. Blending ratio of 4,4'-dimethyl-2,2'-dipyridyl or 2,4,6-tris(dimethylaminomethyl)phenol to dialkyltin compounds, diaryltin compounds, monoalkyltin compounds, and monoaryltin compounds is usually 0.4 to 50%, preferably 0.4 to 40%. The larger the amount of the tin compound as a catalyst used in the present invention, the more the reaction proceeds at a lower temperature and a polymer is obtained.
Preferably it is 0.1-1%. Further, 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. Example 1 500 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.) was completely dissolved in 100 parts of toluene at 80 to 100°C, and the mixture was stirred. Meanwhile, 73 parts of diethylamine is added dropwise at 80-100°C. After addition, while stirring the mixture
Heat at 120℃ for 2 hours. Thereafter, 280 parts of dehydrated coconut oil fatty acid were added, and the mixture was heated under reflux at 200°C for 5 hours to distill off the produced water, followed by reducing the pressure and distilling off toluene. Cool it to 100°C and add 300 parts of butyl acetate. To this, 90 parts of ethyl cellosolve was added in advance to 174 parts of tolylene diisocyanate (a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate) at 60°C for 2 hours with stirring under a nitrogen atmosphere. 60 minutes after dripping
264 parts of a partially blocked diisocyanate prepared by holding at 100°C for 2 hours with stirring.
After addition over ~1.5 h, the reaction mixture was heated to 120 °C.
Hold for 2 hours to react. Next, heat this at 50-60℃
After cooling to , 60 parts of acetic acid and 1365 parts of deionized water are added to obtain a 40% solids paint base for electrocoating. 40% paint base manufactured by the above method
100 copies include 6 parts of Bengara, 6 parts of titanium white, and 1st to 2nd parts.
Add the dialkyltin compound, diaryltin compound, monoalkyltin compound, and monoaryltin compound listed in the table and 4,4'-dimethyl-2,2'-dipyridyl or 2,4,6-tris(dimethylaminomethyl)phenol. After kneading in a ball mill for 20 minutes, diluted with 288 parts of deionized water to obtain a solids content of 13%.
A pigment dispersion composition having a pH of 5.5 to 6 is prepared. Using this as an electrodeposition bath, electrodeposit on a degreased steel plate at 50V for 1 minute, then wash with tap water and pre-dry (80℃, 10 minutes)
After that, they were baked in an electric furnace at various temperatures for 20 minutes, and the results are shown in Tables 1 and 2. In addition, the symbol ○ in the table means completely cured, △ means cured but with stickiness, and × means uncured.

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Claims (1)

[Claims] 1. The blocked isocyanate compound and the active hydrogen-containing compound are combined with at least one compound selected from the group consisting of dialkyltin compounds, diaryltin compounds, monoalkyltin compounds, and monoaryltin compounds, and 4,4'-dimethyl- A method for producing a polyurethane polymer, which comprises reacting in the presence of 2,2'-dipyridyl or 2,4,6-tris(dimethylaminomethyl)phenol.