Colored waterborne polyurethane and preparation method thereof

Abstract

The invention discloses colored waterborne polyurethane which is prepared from the following raw materials in parts by weight: 50-200 parts of diisocyanate, 150-350 parts of conventional dihydric alcohol, 50-120 parts of colored polyester polyol, 1-20 parts of micromolecule chain extender, 10-45 parts of hydrophilic chain extender and 400-1200 parts of deionized water. The colored polyester polyol is prepared from the following raw materials in parts by weight: 20-100 parts of binary acid, 30-110 parts of a micromolecular chain extender, 5-20 parts of dye containing active hydroxyl and 0.1-0.5 part of tetrabutyl titanate, wherein the mole number of hydroxyl to carboxyl is (1.1-1.3): 1. According to the colored waterborne polyurethane, the colored group is synthesized into a polyurethane molecular chain in situ through a chemical reaction, and the dye is combined with polyurethane through a chemical bond, so that the defects of color migration, low rubbing fastness and low water fastness are overcome; meanwhile, the dye and the polyurethane are in the same molecular structure and belong to a system, so that the stability is higher, and the flooding phenomenon is avoided. When being applied to the microfiber leather, the colored waterborne polyurethane has higher color fastness to washing, color fastness to rubbing and color migration resistance levels.

Description

technical field [0001] The invention relates to the field of polymer synthesis, in particular to a colored water-based polyurethane and a preparation method thereof. Background technique [0002] my country is the world's largest producer and exporter of textiles. The sustained and steady growth of textile exports is crucial to ensuring my country's foreign exchange reserves, balance of payments, stable RMB exchange rate, social employment and sustainable development of the textile industry. Especially in recent years, my country's PU synthetic leather has developed extremely rapidly. According to statistics, China's synthetic leather output in 2019 was 3.2828 million tons, a year-on-year increase of 9.6%. [0003] Water-based polyurethane is widely used in textile printing and dyeing, leather processing and other fields due to its special molecular structure and aggregation state structure, which has good film-forming properties, excellent thermal and mechanical properties,...

AI Technical Summary

Problems solved by technology

[0004] At present, polyurethane synthetic leather generally achieves different color styles by physically blending water-based polyurethane and dyes. The existing blending technology has the following problems: dyes, water-based polyurethane, and fabrics are combined by weak forces such as hydrogen bonds and van der Waals forces. Together, the color is not firm and easy to migrate; in addition, the dye is in a metastable state after being blended with water-based polyurethane, and it will stratify and float during placement. The preparation of colored water-based polyurethane is an effective solution to the above-mentioned problems of current water-based polyurethane products. way

[0005] CN104193952B discloses a kind of colored polyurethane emulsion for waterproof coating and its preparation method, its principle is to introduce color-developing chain extender in polyurethane synthesis stage, and chromophoric group is introduced in polyurethane main chain; This method needs to adopt high reactivity Toluene diisocyanate and step-by-step heating method (reaction temperature<120°C) to improve the reaction efficiency with chromophoric groups, while limiting the scope of application, there is still the problem that the utilization rate of chromogenic chain extender is not high

[0006] CN104693403B discloses a colored polyurethane resin for synthetic leather and a preparation method thereof, the principle of which is to introduce a chromophoric group into the polyurethane molecular chain during the polyurethane synthesis stage by using a dye containing dihydroxyl or bis-primary amino groups to solve the problem of color migration; Organic solvents are used in the preparation process, causing pollution and potential safety hazards

[0007] CN106496489B discloses a water-soluble color chain extender, copolymerized color polyurethane emulsion and color polyurethane-acrylic ester copolymer emulsion and preparation method, which introduces at least two amino groups into water-soluble dyes through modification, and then in the polyurethane synthesis stage The water-soluble color chain extender molecules are introduced into the polyurethane molecular chain to solve the problem of color fastness; however, the amino group reacts violently with the isocyanate group and releases a lot of heat. The reaction stage is easy to cause gel phenomenon, the synthesis process is difficult to control, and there are potential safety hazards

[0008] Although the above methods can introduce chromophoric groups into the polyurethane molecular chain, there are still problems of low dye utilization rate and difficult control of the reaction, which limit its practical application in industrial production.

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