| Solvent-based polyurethane inks are still the main market for food packaging,architectural coatings and book printing.With the advancement of environmental policies,it has become an inevitable trend to replace traditional solvent-based inks with safer and more environmentally friendly water-based inks.Conventional water-based polyurethane has some defects in water resistance and adhesion.The purpose of this work is to produce water-based polyurethane ink binders with excellent performance.To this end,the following actions are mainly taken.A number of WPU emulsions with different DMPA materials were synthesized using dimethylolpropionic acid(DMPA)as the hydrophilic monomer and the relationship between the WPU emulsion and the properties of the film and the content of hydrophilic monomers was explored.The study found that as the DMPA content increased,the tensile strength of the water-based polyurethane film increased from 2.64 MPa to 16.91 MPa,and the brake length increased from 436.89% to 954.03%.The water contact angle decreases from 93°to 81.3°,the water absorption increases from 4.87% to 9.15%,and the water resistance decreases.When the DMPA content is 4% by weight,aqueous polyurethane works great.To further improve its water resistance,trimethylpropane crosslinking agent(TMP)was introduced to modify it and a series of WPU emulsions with different materials and the effect of TMP content on emulsion and film properties were prepared.The study found that with increasing TMP content,crosslinking between water-based polyurethane segments increased and storage stability decreased.The adhesion strength of PVC materials increased from 2.21 k N/m to 2.52 k N/m and then decreased to 0.4 k N/m.The tensile strength of the film increased from 8.38 MPa to 17.6 MPa,the brake length decreased from1054.28% to 597.53%,the water resistance of the film was improved and the thermal stability of the film was improved.The long chains of aliphatic hydrocarbons,dodecanol,dodecanadiol and glycerol monolaurite,respectively,were selected to modify the adhesion of aqueous polyurethane to improve the adhesion of the film to the non-polar film surface and their properties were studied.Effects on the properties of emulsions and films.The particle size of the glyceryl monolorate modified emulsion is 157.2 nm,the maximum tensile strength of the film is12.27 MPa,the maximum breaking length is 1164.06%,the water contact angle of the film is 110°,and water absorption is 3.95%,the best water resistance and thermal stability.Water-based polyurethane was modified by 337 acid red dye molecules to form water-based polyurethane dye polymers.Compare the performance variation with the physical mixing method and explore the effect of the coloring material on performance.After testing and characteristics,the tensile strength of the water-based polyurethane dye polymer film was found to be the highest,which was 18.29 MPa,the brake length was the longest,which was 1342% and had the highest thermal stability.As the dye content increased,the particle size of the emulsion increased from 70.9 nm to 200.1 nm,and the emulsion consistency decreased.Tensile strength first increased from 6.28 MPa to 13.13 MPa and then decreased to 6.71 MPa,brake length decreased from 1069.92% to 493.28%,and mechanical properties decreased.The thermal stability of the film first increased and then decreased.The water contact angle of the adhesive film gradually decreased from109.2° to 70.4°,the water absorption rate gradually increased from 5.90% to 9.08%,and the water resistance decreased.The SEM segment was gradually degraded and granular irregularities appeared. |
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