Preparation method of polyurethane curing agent

A polyurethane curing agent and ester solvent technology, applied in polyurea/polyurethane coatings, coatings, etc., can solve problems affecting product quality, affecting curing agent performance, reducing resin compatibility, etc., to achieve excellent yellowing resistance , good economic value, and the effect of improving stability

Inactive Publication Date: 2019-05-31
SHANGHAI INABATA FINE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chemical reaction method has simple process, convenient operation and low cost, but the disadvantage is that during the reaction, part of the reactants will react with the HDI prepolymer, resulting in an increase in viscosity and affecting the quality of the product
Solvent extraction consumes a large amount of solvent and is difficult to operate, so it is difficult to be widely used in industrial production
The molecular distillation method requires long-term high-temperature heating of the crude product, and isocyanate is prone to generate allophanate above 150°C, which affects product quality
The thin film evaporation method is to preheat the prepolymer to a certain temperature, make it flow into the thin film evaporator, and apply the prepolymer evenly on the heated wall through the scraper of the thin film evaporator to form a liquid film, so that the monomer Volatilize and separate from the liquid film, and cool and collect through the cooling device; thin film evaporation method is a relatively mature technology at present, so it is widely used, but due to the low monomer concentration during thin film evaporation separation, the prepolymer after separation is prone to crystallization , The phenomenon of agglomeration will affect the performance of the curing agent and will reduce its compatibility with the resin, affecting the performance of polyurethane coatings; therefore, if the dispersibility of the curing agent can be improved, it is a problem that needs to be solved

Method used

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  • Preparation method of polyurethane curing agent
  • Preparation method of polyurethane curing agent
  • Preparation method of polyurethane curing agent

Examples

Experimental program
Comparison scheme
Effect test

preparation example 1

[0042] Preparation example 1: ① Dehydrate trimethylolpropane and dimethylolpropionic acid at a temperature of 100°C and a vacuum of 0.06MPa for 1.5h;

[0043] ②Stir 10kg of dehydrated trimethylolpropane and 10kg of n-butyl acetate at a temperature of 70°C for 10min to obtain mixture A; mix 4kg of dehydrated dimethylolpropionic acid and 1kg of triethylamine at 60°C Stirring for 10 min under the temperature, to obtain the mixture B;

[0044] ③Under the protection of nitrogen, take 35kg of hexamethylene diisocyanate, 10kg of polyethylene glycol, 0.1kg of dibutyltin dilaurate, and 0.1kg of dibutyltin diacetate, and stir at a temperature of 50°C at 60 drops / min Mixture A was added dropwise while stirring, and mixture B was added dropwise at a rate of 60 drops / min after the addition of mixture A; then the temperature was raised to 60°C, and the reaction was kept for 2 hours; the temperature was continued to rise to 80°C, and phosphoric acid barrier Polymerizing agent 0.1kg, keep wa...

preparation example 2

[0046] Preparation example 2: ① Dehydrate trimethylolpropane and dimethylolpropionic acid for 1.8 hours at a temperature of 105°C and a vacuum of 0.075MPa;

[0047] ② Stir 12.5kg of dehydrated trimethylolpropane and 12.5kg of n-butyl acetate at a temperature of 75°C for 15min to obtain mixture A; mix 5kg of dehydrated dimethylolpropionic acid and 2kg of triethylamine Stirring at a temperature of 65°C for 15 minutes to obtain mixture B;

[0048] ③Under the protection of nitrogen, take 37.5kg of hexamethylene diisocyanate, 12.5kg of polyethylene glycol, 0.125kg of dibutyltin dilaurate, and 0.125kg of dibutyltin diacetate, and stir at a temperature of 53°C. Add mixture A dropwise at a rate of 60 drops / min while stirring, and add mixture B dropwise at a rate of 60 drops / min after the addition of mixture A; Add 0.15kg of benzoyl chloride polymerization inhibitor, keep warm for 35min, then cool down to 45°C to obtain crude product;

[0049] ④ Use a thin-film evaporator to separate...

preparation example 3

[0050] Preparation Example 3: ① Dehydrate trimethylolpropane and dimethylolpropionic acid for 2 hours at a temperature of 110°C and a vacuum of 0.09MPa;

[0051] ②Stir 15kg of dehydrated trimethylolpropane and 15kg of n-butyl acetate at 80°C for 20min to obtain mixture A; mix 6kg of dehydrated dimethylolpropionic acid and 3kg of triethylamine at 70°C Under the temperature, stir 20min, obtain mixture B;

[0052] ③Under nitrogen protection, take 40kg of hexamethylene diisocyanate, 15kg of polyethylene glycol, 0.15kg of dibutyltin dilaurate, and 0.15kg of dibutyltin diacetate, and stir at a temperature of 55°C at 60 drops / min Mixture A was added dropwise while stirring, and mixture B was added dropwise at a rate of 60 drops / min after the addition of mixture A; then the temperature was raised to 65°C, and the reaction was kept for 3 hours; the temperature was continued to rise to 90°C, and phosphoric acid resist Polymerizing agent 0.2kg, keep warm for 40min, then cool down to 50°...

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Abstract

The invention discloses a preparation method of a polyurethane curing agent and belongs to the technical field of curing agents. The preparation method includes following steps: S1, under protection of nitrogen, enabling oxygen content in a reaction environment to be less than or equal to 1%, and stirring hexamethylenediisocyanate prepolymer, ester solvent, aromatic hydrocarbon organic solvent anddispersant at normal temperature and normal pressure for 20-30min to obtain a mixture; S2, adding a water remover into the mixture, continuing stirring for 5-10min, and using a screen with 100-400 meshes for filtering to obtain the polyurethane curing agent. Through cooperation of the dispersant and the solvent, agglomeration of the hexamethylenediisocyanate prepolymer can be reduced, dispersityof the prepolymer can be improved, and fluidity of the curing agent can be improved.

Description

technical field [0001] The present invention relates to the technical field of curing agent, more specifically, it relates to a kind of preparation method of polyurethane curing agent. Background technique [0002] Polyurethane coatings are currently a more common type of coatings, which can be divided into two-component polyurethane coatings and one-component polyurethane coatings; two-component polyurethane coatings are generally composed of isocyanate prepolymers and hydroxyl resins, usually called curing Agent components and main agent components; where the curing agent is also called curing agent or crosslinking agent. The polyurethane coating curing agent can coexist stably with the resin for a long time at room temperature, and the isocyanate (-NCO) group released by the curing agent reacts with the hydroxyl group, carboxyl group, amino group and other groups on the molecular chain of the resin to form a cross-linked network during heat treatment. The degree of cross...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/79C08G18/48C08G18/34C08G18/32C09D175/04C09D7/00
Inventor 陆彩峰朱卫红刘红艳
Owner SHANGHAI INABATA FINE CHEM CO LTD
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