Preparation And Application Of Solvent-free Polyurea Pigment Printing Adhesive

Paint printing has a long history.Due to its fast and simple printing process,clear outlines and changing patterns,it has attracted more and more attention.At present,the commonly used printing adhesives are mainly acrylate and polyurethane emulsions,which replace the organic solvent with water,they are non-flammable and non-explosive.However,the acrylate-based adhesive film has hot-stick,cold-shear and hard feel,and the fastness is not high.Polyurethane adhesives have problems such as excessive baking temperature and poor resistance to moisture and heat.At the same time,common printing adhesives generally have problems in production of waste water,exhaust gas and free formaldehyde.Therefore,the development of green energy-saving paint printing adhesives has become a trend in the development of the industry.Polyurea is a polymer with a theoretical solid content of 100%.Since its invention in the 1980 s,it has become a new type of green paint with excellent wear resistance,adhesion,corrosion resistance and excellent mechanics,it is widely used in chemical protection,bridge protection,pipeline anti-corrosion,marine anti-corrosion and aviation anti-corrosion.The raw material A component of the polyurea is an isocyanate component,and the B component is composed of an amino resin and an amino chain extender.When used,the two components are compounded in proportion.Since the reaction of the isocyanate group with the amino group is high,the reaction is generally completed in a few seconds to several tens of seconds,so that a special spraying equipment is required,and the reaction speed is too fast,resulting in poor leveling of the coating and short wetting time with the substrate,low adhesion.Therefore,the treatment of polyurea raw materials to prepare polyurea with moderate reaction speed,no need for professional spraying equipment and in line with the textile industry has become one of the development trends.This paper mainly carries out four parts of work:The first part,the preparation of the latent curing agent: the polyetheramine D2000 was blocked with methyl isobutyl ketone,and the ketimine-type latent curing agent D2000-MIBK was synthesized,and compounded with hexamethylene diisocyanate trimer(3HDI).Analysis by the system at room temperature gel time and 80℃gel time,curing time and curing kinetics,the results showed that D2000-MIBK/3HDI system can exist stably in dry room temperature environment,and it has certain stability after two-component mixing.Rapid curing can occur when the baking temperature reaches 80℃.Compared with polyurethane and polyacrylate adhesives,polyurea greatly reduces the baking temperature and no moisture evaporation,which saves energy and does not require professional spraying equipment.The second part is the screening of polyurea printing adhesives.The selection of polyurea printing adhesives is mainly based on the gel time and feel of the adhesive.Among them,the gel time is 40~80 minutes,and the hand is soft and non-sticky.Through a large number of experimental investigations,it was finally determined that the adhesive formulation was A component 3HDI: SP-103P=30%: 70%(ratio of the amount of matter),and B component D2000-MIBK: 6200=60%: 40%.The gel time under the formula is 70 min,the film forming feel is not sticky,high tensile strength,high temperature resistance,and has good damping performance and noise reduction performance.At the same time,the adhesive is anhydrous,free of organic solvents,and completely green.The third part is to formulate the printing coating and determine the printing process.Through experiments,it is finally determined that the printing coating is composed of a binder,a thickener,and a color paste.The dosage is 0.5%.Printing process is transfer coating or direct printing: the transfer coating is to print the pattern on the release paper,and after baking at 80 °C for 1 min,the pattern is transferred to the fabric and baked for 3 min;The pattern is directly printed on the fabric,baked at 80 °C for 5 min,and the printed fabric is tested for performance.The fourth part,the preparation of functional polyurea film: in order to further expand its application in textiles to meet the needs of different taking,water-proof and oil-proof polyurea film with water-proof grade 8 and oil-proof grade 6 or above was prepared by introducing silicon-containing substances;a gas permeable polyurea film having a certain gas permeability was prepared by adding a porogen.