Application Of Polyurethane In Textile Dyeing And Finishing

Dyeing with

Auxiliary.

The waterborne polyurethane containing amine compounds has very good fixation effect on common anionic water-soluble dyes.

CooddardR.J. and SanchelM. et al. By using tertiary amine introduced into PU macromolecules, quaternary amination of halogenated alkanes, neutralization of tertiary amines with small molecular acids, insertion of halogen compounds (2,3- dibromo succinic acid), and introduction of quaternary ammonium salts with small molecules to quaternary ammonium salts, [16-17] prepared waterborne polyurethane fixing agents.

The fixing agent can improve the colourability, stain resistance and abrasion resistance of dyed fabrics.

Studies have shown that the reactive polyurethane prefixing resin fixative prepared by the reaction of two ethylene three amine with the appropriate amount of -NCO in the polyurethane prepolymerization system and epichlorohydrin, and the reactive polyurethane prepolymer resin whose terminal group is a reactive epoxy or halogenated alcohol group has obvious improvement on the main color fastness of Direct Dyestuffs, reactive dyes and acid dyed fabrics, especially the wet rubbing fastness, and the fabric discoloration is all above 4 grade. The general formaldehyde free fixing agent has little effect on improving the wet rubbing fastness of the colored cloth.

Waterborne thermal reactive polyurethane fixing agent also has the following excellent characteristics.

Low temperature processing - waterborne polyurethane fixing agents often introduce hydroxyl, carboxyl, amino, Xian Anji and other active groups in their molecular structure, not only can they form a large number of hydrogen bonds, but also can crosslink with fibers.

In addition, the use of sodium sulfate or Sodium Bisulfite capped waterborne polyurethane fixing agent has very low unsealing temperature. Softening effect water-based polyurethane has the "soft segment" structure to increase the flexibility of the molecule, so it can give fabric softness to a certain extent. The friction properties of polyurethane itself can improve the breaking elongation, breaking strength and friction properties of the fabric. It has strong biodegradability and no metal salt, which fully meets the requirements of "ECO" (ECO) label.

In addition, cationic water dispersible polyurethane can also be used to improve dyeability of fabrics or non-woven fabrics.

Polyurethane auxiliaries for printing.

At present, PA adhesives are widely used in pigment printing, which are hydroxymethyl acrylamide as self crosslinking monomer.

It has good pparency, strong adhesion to coatings and fibers, and can reduce the proportion of hard monomer and the amount of binder in printing paste to improve the handle.

But when printing large area patterns, the handle is not soft enough. At the same time, the use of hydroxymethyl acrylamide also brings about formaldehyde emission.

If the ratio of PA soft monomer is increased, the vacuum and viscosity will increase.

Yes

Due to the small elongation at break of polyacrylate adhesives, it is easy to produce dew.

In many respects, PU/PA-IPN has shown excellent performance, which can overcome the disadvantages of poor extensibility of PA adhesives, low wet rubbing fastness, easy dust absorption and adhesion. It can significantly improve the softness and abrasion resistance of pigment printing fabrics.

Water soluble polyurethanes containing -NCO can also react with carbamate groups on the active groups in the fibers and carbamate molecules on the polyurethane macromolecule repeat units to further improve the fastness of pigment printing.

The results showed that the pigment printing products made of polyurethane adhesives had soft handle, high color yield and strong rubbing fastness, which were significantly higher than the national standard (dry 2~3/ wet 2) of pigment printing and others.

The GB requirements (dry 3/ wet 2~3) are comparable to those of dyed fabrics and even exceed the latter.

Cui Jinfeng, et al. Synthesized single component ambient temperature oxidation crosslinking waterborne polyurethane resin can be deeply cross-linked, which overcomes the defects of poor adhesion fastness, low water resistance and poor wear resistance of linear polyurethane film on the substrate.

Fully meet the screen printing process requirements, curing formed by high gloss, water resistance, strong adhesion, bright color, good handle, is an excellent environment-friendly paint screen printing auxiliaries.