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Process for preparing polyisocyanate composition by using recycled monomer

A technology of polyisocyanate and diisocyanate, which is applied in the field of preparation technology, can solve the problems of damp products, easy flocculation and precipitation, complicated operation, etc., and achieve the effect of solving difficult processing problems and excellent flocculation stability

Active Publication Date: 2022-02-25
WANHUA CHEMICAL (NINGBO) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In addition, when using the polyisocyanate composition to prepare downstream applications, the polyisocyanate is generally mixed with the main agent. When the necessary addition amount is a small amount, it is often necessary to open and close the same storage tank multiple times to take the polyisocyanate. There is a problem that the product is easy to flocculate and precipitate when it is damp
For this problem, the prior art mostly solves it by adding additional water scavengers, such as adding diphosphate tetraester in CN110621712A, adding trialkyltin chloride in EP2038746A1, adding bistrimethylsilylacetamide in US2008257214A1 Or hexamethyldisilazane, etc., but these compounds must be added stoichiometrically, the operation is complicated, and the decomposition products formed consume NCO groups, affecting downstream applications

Method used

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  • Process for preparing polyisocyanate composition by using recycled monomer
  • Process for preparing polyisocyanate composition by using recycled monomer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Under the condition of nitrogen protection, heat 1000g of fresh HDI monomer in a water bath at 60°C for 1h, add 0.5g of 2-hydroxy-N,N,N-trimethyl-1-propanamine formate Trimerization was carried out with n-butanol solution (0.62 mmol). When the NCO content in the reaction solution reached 39.3%, 0.16 g of di-n-butyl phosphate (0.76 mmol) was added to terminate the reaction. Next, it was purified twice using a thin film evaporator under the conditions of 150° C. and 0.2 Torr to obtain a polyisocyanate composition A having a HDI monomer mass concentration of 0.16% and about 600 g of recovered monomers. The acid value of the recovered monomer was tested to be 155mgKOH / 100g.

[0063] The above-mentioned 600g recovery monomer and 750mg KOH were mixed and stirred at room temperature for 60min, after 1um membrane filtration, the acid value of the test filtrate was 30mgKOH / 100g. The reclaimed monomer after treatment is mixed with 400g fresh HDI monomer, carry out trimerization...

Embodiment 2

[0065] Under nitrogen protection conditions, 1000g of fresh HDI monomer was heated in a 60°C water bath for 1h, and 0.25g of a 20% mass concentration of trimethylbenzyl ammonium hydroxide in n-butanol (0.30mmol) was added for trimerization. When the NCO content in the reaction solution reached 39.3%, 0.08 g of di-n-butyl phosphate (0.36 mmol) was added to terminate the reaction. Next, it was purified twice using a thin film evaporator under the conditions of 145°C and 0.2 Torr to obtain a polyisocyanate composition C with a HDI monomer mass concentration of 0.16% and about 600 g of recovered monomers. The acid value of the recovered monomer was tested to be 103mgKOH / 100g.

[0066] Above-mentioned 600g recovery monomer and 516mg KOH are mixed and stirred 60min at room temperature, after 1um membrane filter, test filtrate acid value is 17mgKOH / 100g. The reclaimed monomer after treatment is mixed with 400g of fresh HDI monomer, carry out trimerization reaction and prepare polyis...

Embodiment 3

[0068] Under the condition of nitrogen protection, heat 1000g fresh HDI monomer in 70°C water bath for 1h, add 2.0g n-butanol solution (1.17mmol) of (2-hydroxyethyl)triphenylphosphine chloride with a mass concentration of 20% carry out the trimerization reaction. When the NCO content in the reaction solution reached 39.3%, 0.179 g (1.4 mmol) of dimethyl sulfate was added to terminate the reaction. Next, it was purified twice using a thin film evaporator under the conditions of 140°C and 0.2 Torr to obtain a polyisocyanate composition E with a HDI monomer mass concentration of 0.20% and about 600 g of recovered monomers. The acid value of the recovered monomer was tested to be 95mgKOH / 100g.

[0069] The above-mentioned 600g recovery monomer and 546mg KOH were mixed and stirred at room temperature for 60min, after 1um membrane filtration, the test filtrate acid value was 4mgKOH / 100g. The treated recovered monomer was mixed with 400 g of fresh HDI monomer, and trimerization was...

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Abstract

The invention discloses a process for preparing a polyisocyanate composition by using a recycled monomer, which comprises the following steps: 1) carrying out trimerization reaction on diisocyanate under the action of a catalyst K, and terminating the reaction after the target conversion rate is reached; 2) refining the reaction liquid, and separating to obtain a polyisocyanate composition and an unreacted diisocyanate monomer; and 3) adjusting the acid value of the unreacted diisocyanate monomer to 1-80mgKOH / 100g, mixing the unreacted diisocyanate monomer with fresh diisocyanate, and recycling the mixture to the trimerization reaction in the step 1) to prepare the polyisocyanate composition product. The method can be used for preparing the polyisocyanate composition with light color and excellent flocculation stability.

Description

technical field [0001] The present invention relates to a kind of preparation technology, relate in particular to a kind of technology that utilizes recycled monomer to prepare polyisocyanate composition. Background technique [0002] Polyurethane resin coatings are often used as coatings with excellent abrasion resistance, chemical resistance, and stain resistance, especially non-yellowing polyisocyanates derived from aliphatic isocyanates such as hexamethylene diisocyanate and isophorone diisocyanate The polyurethane resin coating has more excellent weather resistance. [0003] In the process of preparing the polyisocyanate composition, a certain amount of unreacted free monomers often remains after the reaction is completed. Excessive free monomer content will not only endanger the environment and human health, but also affect the further development of products. Therefore, all countries have regulations on free isocyanate in products. For example, the European Union req...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/73C08G18/75C08G18/79
CPCC08G18/792C08G18/735C08G18/755C08G18/758Y02W30/62
Inventor 胡浩孙立冬俞涛尚永华史培猛王少华韩海涛谢雪坤邓益良
Owner WANHUA CHEMICAL (NINGBO) CO LTD
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