Method for preparing amino-terminated polyurethane

Abstract

The invention relates to the technical field of preparation of active amino-terminated functional compounds, in particular to a method for preparing amino-terminated polyurethane by using a steric hindrance protection method. The method concretely comprises the following steps: respectively selecting isophorone diisocyanate and isophorone diisocyanate which have similar functional groups and different reactive activities as blocking modification raw materials; realizing a reaction rate gradient through steric hindrance protection; and directly functioning amino at two ends of a main structure to prepare the amino-terminated polyurethane. The amino-terminated polyurethane is directly and efficiently prepared through the steric hindrance protection method, thus, the defect that isocyanic acid rapidly reacts with the amino is avoided, the reaction process has a certain speed gradient, the generation of a crosslinking structure is inhibited, the production risk and the production energy consumption are remarkably reduced, and the product performance and the production efficiency are increased.

Description

technical field [0001] The invention relates to the technical field of preparation of active amino-terminated functional compounds, in particular to a method for preparing amino-terminated polyurethane by a steric hindrance protection method. Background technique [0002] At present, amino-terminated polyurethanes on the market are usually prepared by reacting isocyanate-terminated polyurethane prepolymers with highly reactive diamines. Because the reaction rate of isocyanate reacts with amino groups to form urea bonds is extremely fast, and the two reactants are Two or four functionalities, so the risk of gel polymerization in production is extremely high. It is necessary to protect the primary ammonia by adding acetone, that is, to prepare amino-terminated polyurethane by chemical protection method. Due to the inevitable energy loss when removing the solvent acetone The consumption increases, and the residual solvent will affect the performance of amino-terminated polyuret...

AI Technical Summary

Problems solved by technology

[0002] At present, amino-terminated polyurethanes on the market are usually prepared by reacting isocyanate-terminated polyurethane prepolymers with highly reactive diamines. Because the reaction rate of isocyanate reacts with amino groups to form urea bonds is extremely fast, and the two reactants are Two or four functionalities, so the risk of gel polymerization in production is extremely high. It is necessary to protect the primary ammonia by adding acetone, that is, to prepare amino-terminated polyurethane by chemical protection method. Due to the inevitable energy loss when removing the solvent acetone The consumption increases, and the residual solvent will affect the performance of amino-terminated polyurethane to some extent

[0003] In recent years, spray-coated polyurea elastomers have been developed on a large scale due to their excellent performance, but the spray-coated polyurea elastomers widely used in China still have some performance defects, the main reason is that pure polyurea products are expensive

Spraying polyurethane / urea is widely used in the market. Since the polyurea system is doped with polyurethane, the reaction mechanism of polyurethane is quite different from that of polyurea. Urea bonds are easier to form than ester bonds, resulting in system compatibility. The performance of sprayed products is difficult to guarantee, so the polyurea products on the market are fake, and the quality is uneven

Similarly, epoxy resin has been widely used in aerospace, machinery, chemical industry, construction and other fields due to its excellent comprehensive performance. Therefore, the modification of epoxy resin has always been a hot topic in the research field.

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