Preparation method of light-colored polyisocyanate curing agent

A technology of polyisocyanate and diisocyanate, which is applied in the field of preparation of light-colored polyisocyanate curing agent, can solve problems such as high reaction temperature, difficulty in monitoring reaction temperature, and uneven distribution of alcohol components, so as to control the color number of the product and prevent localized The effect of high temperature

Active Publication Date: 2014-06-25
WANHUA CHEM GUANGDONG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are also disadvantages in the method of dripping: the contact area between the alcohol component and the diisocyanate component is concentrated at one point for a long time, and the distribution of the alcohol component in the whole system is uneven, which easily causes the local reaction temperature to be too high, forming a temperature inside the system Gradient, the reaction temperature is difficult to monitor, which in turn affects the color number of the curing agent product

Method used

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  • Preparation method of light-colored polyisocyanate curing agent
  • Preparation method of light-colored polyisocyanate curing agent
  • Preparation method of light-colored polyisocyanate curing agent

Examples

Experimental program
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Embodiment 1

[0059] Trimethylolpropane with a carbonyl compound content of 0.02wt% is added dropwise to the conical liquid distribution pan and dispersed into the reactor containing 5Kg of toluene diisocyanate component (the liquid level is about 70% of the reactor height) The reaction is carried out in , the two satisfy the NCO / OH molar ratio of 4, the reactor diameter D is 20cm, the height H is 20cm, the distance △h between the distribution plate and the top of the reactor is 1cm, the height h of the distribution plate is 2cm, and the top angle of the distribution plate is α is 55°, holes are opened on the surface of the distribution plate, the hole diameter is 5mm, the opening ratio is 0.6, the rotation speed is 300rpm, the dropping time is 60min, the reaction temperature is 50°C, and the reaction time is 4h to obtain the prepolymer reaction liquid; the prepolymer reaction The liquid is separated by a two-stage thin-film evaporator, the primary temperature is 120°C, the absolute pressure...

Embodiment 5

[0067] Remove carbonyl compounds from trimethylolpropane and 1,4-butanediol respectively to obtain a mixed alcohol component with a carbonyl compound content of 0.02wt%. The mass ratio of trimethylolpropane to 1,4-butanediol is 3 : 1; the mixed alcohol component is dispersed in the reactor equipped with 60Kg of toluene diisocyanate component (its liquid level height is about 60% of the height of the reactor) by dropping it on the conical liquid distribution plate and reacting, The molar ratio of NCO / OH is 6, the diameter D of the reactor is 40cm, the height H is 70cm, the distance △h from the distribution plate to the top is 5cm, the height h of the distribution plate is 10cm, the top angle α of the distribution plate is 40°, the surface of the distribution plate Open holes with a pore diameter of 10mm, a porosity of 0.4, a rotational speed of 250rpm, a dropping time of 80min, a reaction temperature of 80°C, and a reaction time of 6h to obtain a prepolymer reaction solution; th...

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Abstract

The invention relates to a preparation method of a light-colored polyisocyanate curing agent. The preparation method comprises the following steps: (a) purifying a raw material-trimethylolpropane to obtain trimethylolpropane with the carbonyl compound content lower than 0.1wt%; (b) reacting trimethylolpropane with the carbonyl compound content lower than 0.1wt% or a mixture of trimethylolpropane with the carbonyl compound content lower than 0.1wt% and micromolecular dihydric alcohol with excess diisocyanate in a reactor with a conical liquid distribution plate to obtain a liquid-state prepolymer reaction solution containing excess diisocyanate; and (c) removing monomers from the prepolymer reaction solution obtained in the step (b) by adopting a two-stage film evaporator, and diluting by a solvent to obtain the curing agent with the diisocyanate monomer content lower than 0.5wt%. The color number of the diisocyanate curing agent prepared based on the method can be lower than 20Hazen.

Description

technical field [0001] The invention relates to a preparation method of a light-colored polyisocyanate curing agent. Background technique [0002] Polyisocyanate curing agent is one of the "two-components" in two-component polyurethane coatings, and its quality will directly affect the application performance of the coating. The preparation principle is based on the prepolymerization reaction of diisocyanate components and small molecule polyols. Obtain the prepolymer of terminal NCO group, then remove the diisocyanate monomer and dilute to obtain the product. [0003] At present, the market demand for polyisocyanate curing agents prepared based on trimethylolpropane is large, accounting for about 30% of the polyurethane curing agent market. The main process is: first use excess diisocyanate components and trimethylolpropane or trihydroxy Prepolymerize the mixture of methyl propane and small molecule diol, remove excess diisocyanate monomer, and dilute with solvent to final...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/76C08G18/32C09D175/04
CPCC08G18/3206C08G18/8035
Inventor 刘伟王玉启尚永华阎洁麦志远石滨黎源
Owner WANHUA CHEM GUANGDONG
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