Water-borne polyurethane not containing organic tin and preparation method thereof

Abstract

The invention discloses a water-borne polyurethane not containing organic tin. The water-borne polyurethane is prepared from the following components in parts by weight: 25 to 80 parts of aromatic polyester polyol, 10 to 20 parts of diisocyanate, 10 to 40 parts of hydroxyalkyl-terminated methyl phenyl polysiloxane, 0.015 to 0.06 part of catalyst, 2 to 10 parts of hydrophilic chain-extending agent, 2 to 10 parts of amine chain-extending agent, 5 to 10 parts of solvent and 2 to 5 parts of salt forming agent, wherein the catalyst is selected from one or two of organic bismuth, organic zinc or organic zirconium. The water-borne polyurethane has the advantages that the hydrophilic chain-extending agent and the hydroxyalkyl-terminated methyl phenyl polysiloxane are used as main polymerizing monomers, so that the hydrolysis-resistant property and heat-resistant property are better; the water-borne polyurethane is more suitable for application environments with complicated water system; the water-borne polyurethane does not contain the organic tin catalyst, so that the more environment-friendly property is realized.

Description

Technical field [0001] The invention relates to the technical field of synthesis of new polymer materials, in particular to a waterborne polyurethane free of organotin and a preparation method thereof. Background technique [0002] Waterborne polyurethane is a binary colloidal system formed by dissolving or dispersing polyurethane resin in water with water as the dispersion medium. It has the advantages of low pollution, non-flammable, energy-saving, hard to damage the painted surface, good working environment, and easy to clean. It also has excellent flexibility, abrasion resistance, low temperature resistance and other excellent properties of solvent-based polyurethane coatings, so it has a broad field in wood coatings, automotive coatings, architectural coatings, plastic coatings, paper coatings, and textile and leather coatings. Application prospects. With the increasing awareness of people's environmental protection and the establishment and strengthening of national safety...

AI Technical Summary

Problems solved by technology

[0005] The main molecular chain of water-based polyurethane contains repeated carbamate group (-NHCOO-) structural units, and the initial thermal decomposition temperature of carbamate bond is relatively low, which is 140-160°C; plus the molecular structure of water-based polyurethane Most of them are linear and less cross-linked; therefore, the heat resistance of water-based polyurethane is generally poor at this stage

When the temperature is 80-90°C, some important mechanical properties of polyurethane, such as modulus, strength, etc., will drop significantly. If the processing temperature exceeds 200°C, polyurethane will undergo thermal degradation, which is far from meeting the heat resistance requirements. Material requirements, which limit the application fields of waterborne polyurethane to a certain extent

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