Knowledge About Polyurethane Printing And Dyeing Auxiliaries

That is, polyurethane is a new type of polymer synthetic material with young's modulus between rubber and plastic.

The synthesis is based on the chemical reaction between the isocyanate group containing highly unsaturated bonds and the active hydrogen compounds.

Polyurethane has excellent abrasion resistance, flexibility and chemical resistance.

Solvent type (oil soluble) polyurethane, due to the use of a large number of solvents (two methylformamide, toluene, acetone, butanone, ethyl acetate, etc.) will inevitably bring high production costs and serious environmental pollution. From the point of view of application, it is also inconvenient, and its compatibility with aquatic chemicals is also very poor, which greatly limits its application in the textile field.

Waterborne polyurethane prepared by introducing hydrophilic / ionic groups into polyurethane macromolecule structure has made up for the shortage of solvent polyurethane.

Waterborne polyurethane can give the textile soft and plump leather handle and wear resistance, crease resistance, shrinkage, resilience, flexibility and breathability. As a kind of dyeing auxiliaries, it has shown broad prospects in fabric finishing, dyeing and printing.

Waterborne capped polyurethane.

Closed waterborne polyurethane is a polyurethane emulsion or solution which is temporarily passivated by partially or wholly active -NCO in polyurethane prepolymer and is temporarily closed by introducing hydrophilic components or by external emulsification and reactivated under suitable heat treatment conditions.

When the polyurethane is heat-treated at 130~160 C, the -NCO group can recover its activity and react with the group containing active hydrogen (hydroxyl, amino, urea, carboxyl, urethane and water) to produce crosslinking.

Because

It usually contains a group of reactive hydrogen which can react with isocyanate groups. Therefore, this "reactive polyurethane" has a strong adhesive fastness to fabrics.

The characteristics of waterborne capped polyurethane.

Reactive waterborne polyurethane (waterborne capped polyurethane) is generally water-soluble polymer prepolymer.

Compared with those commonly used in textile post-processing resins, the thermal reactive water-soluble polyurethane not only maintains the elasticity of polyurethane, but also has excellent reactivity, which can be chemically combined with the active hydrogen groups of fibers and various textile chemicals or produce its own network cross-linking. Therefore, it can endow fabrics with various durable washing functions and improve the added value of textiles. In addition, because it is usually a low molecular weight oligomer, it has high permeability and diffusion to fabrics and fibers; after proper treatment, a durable cross-linking film can be formed on the surface of [1]. fibers.

Application of waterborne capped polyurethane.

This category

It can be widely used in cotton fabrics for washing, waterproofing and flame retardant, durable antistatic, polyester and cotton knitted fabrics with shrinkage resistance and anti pilling finishing, and can be used to improve the tearing strength of woven fabrics.

As a potential curing agent or crosslinking agent, waterborne capped polyurethane is mainly used in pigment printing / dyeing, resin finishing (such as cotton, linen, viscose, Tencel and silk fabric wrinkle resistant finishing), special effects of fabric finishing (such as waterproof and moisture permeable, imitation leather, imitation special texture coating) and hydrophilic, antistatic finishing of chemical fiber fabrics.

In addition, nanomaterials can be well dispersed in aqueous polyurethane solutions without changing the original properties of the materials.

Therefore, the application of waterborne polyurethane will greatly promote the practical application of nano functional materials in the field of textile dyeing and finishing.