Polyether-type water-based polyurethane emulsion and preparation method thereof

Abstract

The invention discloses a polyether-type water-based polyurethane emulsion and a preparation method thereof. The method comprises the following steps: 1) in an inert atmosphere, mixing a chain extender with diisocyanurate, and reacting to obtain a mixture I; 2) in an inert atmosphere, mixing the mixture I with polyether glycol and a hydrophilic chain extender, and reacting to obtain a mixture II; 3) mixing the mixture II with hydroxyacrylate, reacting to obtain a polyurethane prepolymer; and 4) neutralizing the polyurethane prepolymer by adding alkali, adding water, emulsifying, and carrying out radiation crosslinking to obtain the polyether-type water-based polyurethane emulsion. The micromolecule diol and diisocyanate are prepolymerized, the chain segment formed by reaction with polyether chain segment has lower phase reversal difficulty than the polyether prepolymer in the emulsifying process, and the emulsion process can be easily completed when the molecular weight is lower. The Co-60-gamma ray is utilized to perform irradiation crosslinking on the emulsion obtained from the polyurethane prepolymer, thereby effectively enhancing the molecular weight of the water-based polyurethane; and thus, the water-based polyurethane emulsion has high solid content and favorable mechanical properties.

Description

technical field [0001] The invention relates to a polyether-type water-based polyurethane emulsion and a preparation method thereof, belonging to the field of fine polymer materials and preparation thereof. Background technique [0002] Water-based polyurethane (WPU) is a kind of polymer synthetic material, which has the advantages of wear resistance, corrosion resistance, low temperature flexibility, fatigue resistance, etc. It can be used as adhesives for shoes, coatings, fabric coatings, various packaging Adhesives for products, etc., which use water as the dispersion medium, have the advantages of non-combustibility, environmental protection, and little irritation to the human body. The water-based polyurethane with polyether polyol and polyester polyol as the soft segment occupies the vast majority of the water-based polyurethane. Among them, the water-based polyurethane with polyether polyol as the soft segment is used in fabric coating and leather materials with soft ...

AI Technical Summary

Problems solved by technology

[0003] Different from WPU with polyester polyol as soft segment, the molecular chain of polyether polyol as soft segment contains a large number of ether bonds, and its phase inversion rate is significantly slower than that of WPU with polyester polyol as soft segment. Because the chain segment contains hydrophilic groups, it is difficult to increase the solid content of polyether-type WPU. Generally, the solid content of polyether-type WPU is not higher than 40%. The synthesis process also determines that the molecular weight of WPU is difficult to reach a high level. , in the traditional preparation method, the isocyanate is greatly excessive before emulsification, and the general value ([NCO] / [OH]) is greater than 1.3, because the residual isocyanate will continue to react until it is completely consumed, which makes WPU need to The performance of the emulsion can be stabilized for a long time, and the performance of the WPU emulsion is continuously changing during this process

The above deficiencies have adversely affected the application of polyether type WPU

[0004] When preparing WPU, the higher the molecular weight, the greater the viscosity before emulsification, and the greater the difficulty of emulsification, and the low molecular weight of WPU makes it easier to prepare emulsions with high solid content, but at this time the mechanical properties of high solid content waterborne polyurethane are poor

[0005] Aiming at the current problems of low solid content and poor mechanical properties of polyether-type WPU, diaminosulfonate-type emulsifiers are used instead of dimethylol propionic acid to prepare high-solid-content WPU, such as the sulfamate-type emulsifier used in CN201310694240 WPU with high solid content prepared by chain extender, patent CN201110100592 also discloses a WPU with high solid content prepared by using sulfonate chain extender, but in general, it is difficult to prepare and synthesize using sulfamate, diamine The base sulfonate tends to produce gel during emulsification and chain extension, and the water resistance of the product is not good

The use of cross-linking agents to cross-link WPU can improve the physical and chemical properties of WPU, but it is also easy to make WPU cross-links in the synthesis and easily produce gels, which affects the stability of the emulsion. When WPU is used, add water-dispersible polyisocyanate cross-linking method The prepared adhesive has better comprehensive properties, but it is necessary to mix WPU and water-dispersible crosslinking agent before use, which is cumbersome to operate and is not conducive to construction