Preparation method of non-isocyanate polyurethane prepolymer

Abstract

The invention relates to the technical field of photocureable coatings, in particular to a preparation method of a non-isocyanate polyurethane prepolymer. In order to respond to the requirements of national green sustainable development, the use of isocyanate type polyurethane in the water-based photocureable coating is reduced from the source; the invention provides a non-isocyanate polyurethaneprepolymer and a preparation method thereof. The non-isocyanate polyurethane prepolymer is used as a component of the photocureable coating, and is photocured with acrylate, a photoinitiator and the like under certain conditions to form a coating film on the surface of a material; two branched chains on each repetitive unit of the molecular structure of the non-isocyanate polyurethane prepolymer form a spatial three-dimensional structure with relatively high interlacing, winding and crosslinking density with the non-isocyanate polyurethane prepolymer or acrylate; the structure can protect easily hydrolyzed carbamate groups in the molecular structure of the non-isocyanate polyurethane body from contacting with moisture in the air to a certain extent, and greatly improves the water resistance, hardness, glossiness and other properties of the photocurable coating film.

Description

technical field [0001] The invention relates to the technical field of light-curing coatings, in particular to a preparation method of a non-isocyanate polyurethane prepolymer. Background technique [0002] Polyurethane coatings have excellent wear resistance, flexibility, adhesion and chemical resistance, and are widely used in many fields of the national economy such as construction, automobile industry, electromechanical, shipping, aviation, light industry, and textiles. occupies an important position in the industry. [0003] Polyurethanes are usually obtained by reacting polyisocyanates with substances with active hydrogen. And polyisocyanate has following shortcoming specifically as the method for raw material production polyurethane: (1) isocyanate has very strong irritation and toxicity, and long-term contact easily suffers from dermatitis, respiratory disease, asthma, simultaneously, the relative molecular weight of isocyanate is little, and vapor pressure is high ...

AI Technical Summary

Problems solved by technology

And polyisocyanate has following shortcoming specifically as the method for raw material production polyurethane: (1) isocyanate has very strong irritation and toxicity, and long-term contact easily suffers from dermatitis, respiratory disease, asthma, simultaneously, the relative molecular weight of isocyanate is little, and vapor pressure is high , high toxicity, easy to leak and cause danger; (2) isocyanate is very sensitive to moisture, usually, the moisture content of raw materials should be less than 0.3%, otherwise it is easy to produce foaming, which will cause inconvenience to the storage and transportation of raw materials; (3) ) The carbamate group is an easily hydrolyzed group, which can be hydrolyzed under certain conditions, which reduces the water resistance, acid and alkali resistance, and weather resistance of the product; (4) isocyanate is mainly produced by the phosgene method, and there are a large number of Inflammable, explosive, highly toxic and highly toxic substances, the production process is relatively complicated, and there are many control points. Due to the limitations of safety, environmental protection, technology, scale, etc., the industrial production of isocyanate has high entry barriers and is monopolized by a few enterprises. , higher price

However, the one-component water-based polyurethane coating prepared by traditional method has a lower degree of crosslinking. Compared with the solvent-based polyurethane coating, the chemical resistance and water resistance of the one-component water-based polyurethane coating are poor, and the hardness and surface gloss are poor ( Yang Qingfeng, Qu Jinqing, Chen Huanqin. A review of the technical progress of waterborne polyurethane coatings [J]. Chemical Technology Market, 2004 (10): 18-23.), in order to improve the chemical resistance, solvent resistance and other properties of one-component waterborne polyurethane , the usual practice is to blend, copolymerize, and graft polyurethane with other resins. Although this method can greatly improve the performance of one-component waterborne polyurethane, this method cannot reduce isocyanate from the source. usage of

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