Prepolymer used as polyurethane coating curing agent and based on methyl diphenylene diisocyanate, and preparation thereof

A technology of diphenylmethane and diisocyanate, applied in the field of prepolymer based on diphenylmethane diisocyanate and its preparation, can solve the problem of poor storage stability of acetate solution, compatibility of hydroxyl acrylic resin and alkyd resin Poor performance, low functionality and other problems, to achieve the effect of clear and transparent appearance, low color, and low toxicity of the product

Active Publication Date: 2010-10-27
GUANGDONG HUARUN PAINT CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Diphenylmethane diisocyanate is not suitable as a polyurethane coating curing agent directly due to its low functionality, poor storage stability of its acetate solution, and poor compatibility with hydroxyl acrylic resins and alkyd resins.
These two patent documents have tested the storage stability of its acetate solution, and have also considered the application in coatings, but none of the above related patent documents has carried out the test of the construction life after the paint is mixed.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0040] 26.8kg of 1,1,1-trimethylolpropane and 26.8kg of dipropylene glycol were vacuum dehydrated at 105°C to 115°C for 2 to 4 hours before use.

[0041] At this moment, the equivalent ratio of 1,1,1-trimethylolpropane and dipropylene glycol is 6:4,

[0042] Keep its moisture content below 0.04%. Under nitrogen protection, put 262.5kg of diphenylmethane diisocyanate and 316.1kg of butyl acetate into the reaction vessel and stir evenly, maintaining the temperature at 60°C.

[0043] Then slowly add 1,1,1-trimethylolpropane dropwise into the reactor, and keep stirring in the reactor during the dropwise addition to make the materials mix and react evenly, and the dropping time is 90 minutes. Continue to react at 60°C under stirring for 4 hours; then slowly add dipropylene glycol dropwise into the reactor, and keep stirring in the reactor during the dropwise addition to make the materials mix and react evenly, and the dropping time is 2 hours. After the dropwise addition, the rea...

no. 2 example

[0053] 24kg of 1,1,1-trimethylolethane and 38.4kg of tripropylene glycol were vacuum dehydrated at 105°C to 115°C for 2 to 4 hours before use.

[0054] At this moment, the equivalent ratio of 1,1,1-trimethylolethane and tripropylene glycol is 6:4,

[0055] Keep its moisture content below 0.04%. Under nitrogen protection, put 262.5kg of diphenylmethane diisocyanate and 216.6kg of butyl acetate into the reaction vessel and stir evenly, maintaining the temperature at 60°C.

[0056] Then slowly add 1,1,1-trimethylolethane dropwise into the reactor, and keep stirring in the reactor during the dropwise addition to make the materials mix and react evenly, the dropwise time is 90 minutes, and the dropwise addition is completed Then continue to react at 60°C under stirring for 4 hours, then slowly add tripropylene glycol dropwise into the reactor, keep stirring in the reactor during the dropping process to make the materials mix and react evenly, and the dropping time is 2 hours Afte...

no. 3 example

[0066] 26.8 kg of 1,1,1-trimethylolpropane and 26.8 kg of dipropylene glycol were dehydrated in vacuum at 105° C. to 115° C. for 2 to 4 hours respectively to ensure that the moisture content thereof was lower than 0.04%. Under the protection of nitrogen, put 262.5kg of diphenylmethane diisocyanate and 316.1kg of butyl acetate into the reaction vessel, mix and stir evenly, and keep the temperature at 60°C, then add 1,1,1-trimethylol After the propane and dipropylene glycol are fully mixed, slowly drop them into the reactor. During the dropping process, the reactor is kept stirring to make the material uniform. The dropping time is 90 minutes. React for 4 hours, cool down to below 40°C and discharge.

[0067] The curing agent prepared in the third example becomes turbid after being stored at 25° C. for 5 days, and separates after 10 days.

[0068] In this embodiment, in the preparation of the curing agent for polyurethane coatings, the dripping method of firstly adding the trihyd...

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Abstract

The invention relates to a diphenyl-methane-diisocyanate-based prepolymer which can work as a hardener for polyurethane coatings and a preparation method thereof. Small-molecule trihydric primary alcohol, small-molecule dihydric secondary alcohol and substance A react with each other and generate the prepolymer with acetate ester as a solvent; the equivalent proportion of small-molecule trihydricprimary alcohol, small-molecule dihydric secondary alcohol and substance A is 0.4 to 0.8 : 0.2 to 0.6 : 2.1; the weight ratio of the dosage of the acetate ester as a solvent to the total dosage of the small-molecule trihydric primary alcohol, small-molecule dihydric secondary alcohol and substance A as reactants is 30 to 60 : 40 to 70. During the preparation process, the small-molecule trihydric primary alcohol and the small-molecule dihydric secondary alcohol are dripped into the acetic ester solution of substance A in sequence for reaction. The diphenyl-methane-diisocyanate-based prepolymerof the invention, which has low toxicity and good storage stability, is mainly used as a hardener for polyurethane coatings and is characterized by good compatibility after being blended with hydroxylated acrylic resin and alkyd, long service life after the blending with paints, etc.

Description

technical field [0001] The invention relates to a prepolymer based on diphenylmethane diisocyanate as a polyurethane coating curing agent and a preparation method thereof. Background technique [0002] At present, the most commonly used production method of polyurethane coating curing agent in China is to use trimethylolpropane and toluene diisocyanate to react to form a prepolymer. In the process of prepolymer production, unreacted toluene diisocyanate remains. Due to the relatively high vapor pressure of monomeric toluene diisocyanate, 2,4-toluene diisocyanate is 1.3*10 at 20°C -2 mbar; 2,6-toluene diisocyanate is 1.3*10 at 20°C -2 mbar, and toluene diisocyanate vapor is highly toxic and must be removed after prepolymer preparation. However, this step is generally not desired based on cost considerations, and it is indeed difficult to completely remove free toluene diisocyanate in the prepolymer, so the toluene diisocyanate prepolymer on the market still contains a certa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/76C08G18/32C08G18/10C09D175/04
Inventor 温晋嵩曾光明王庆生孔淑香刘超刘晓燕李景宏马红肖
Owner GUANGDONG HUARUN PAINT CO LTD
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