Waterborne cation polyurethane hot melt adhesive preformed polymer and production method of emulsion thereof

Abstract

The invention relates to a waterborne cation polyurethane hot melt adhesive preformed polymer and a production method of emulsion thereof. In early period, low polymer dihydric alcohol, diisocyanate monomer and cation hydrophilic chain extender react at the temperature of 70-90 DEG C for 1-5h to generate preformed polymer; and the late synthesis process comprises the following steps of: (1) adding1-5 parts of a first neutralizing agent to the preformed polymer or not adding; (2) adding 1-10 parts of triisocyanate monomer to the product of step (1); (3) dispersing 2.4-12 parts of a second neutralizing agent in 120-300 parts of water; and (4) dispersing the product of step (2) in the product of step (3). Finally, the waterborne cation polyurethane hot melt adhesive emulsion with the solid content between 25-40 percent is prepared. The method is mature and simple in process and beneficial to large-scale production and can prepare polyurethane emulsion with high degree of crosslinking. The prepared waterborne polyurethane emulsion can be stably stored for over one year at the temperature of 5-35 DEG C, laminated plastic and ink have good bonding effect, and compared with the productsat home and abroad, the waterborne polyurethane emulsion has excellent quality and lower cost.

Description

technical field [0001] The invention relates to a production method of a water-based cationic polyurethane hot-melt adhesive prepolymer and its emulsion. More specifically, the present invention relates to a production method of a water-based cationic polyurethane hot-melt adhesive emulsion capable of long-term storage with a mature and simple process. Background technique [0002] So far, waterborne polyurethane has formed several relatively mature preparation methods, such as acetone method, prepolymer dispersion method, melt dispersion method, ketimine and ketazine method, etc. Nowadays, the synthesis process of water-based anionic polyurethane emulsion has become increasingly mature, and the emulsion can be stored stably for a long period of time. A major problem of cationic polyurethane emulsion is the difficulty of salt formation and emulsification after the preparation of the prepolymer. Most reports at home and abroad use glacial acetic acid as a neutralizer to form...

AI Technical Summary

Problems solved by technology

A major problem of cationic polyurethane emulsion is the difficulty of salt formation and emulsification after the preparation of the prepolymer. Most reports at home and abroad use glacial acetic acid as a neutralizer to form a salt. One is to add glacial acetic acid to the prepolymer to form a salt first. Redispersion; the second is to dissolve glacial acetic acid or other monobasic acids in water, and the prepolymers will form salts and extend chains in water at the same time, but the prepared cationic polyurethane emulsion is difficult to store for a long time