Properties and Advantages of Natural Thickener Sodium Alginate for Textile Printing and Dyeing

In textile printing and dyeing operations, thickener should be added to the printing paste to make the dyes evenly distributed, maintain the clarity of printing effect, and maintain the fluidity of printing paste.

Thickener is generally a polymer with high molecular weight. It gives the necessary viscosity of color paste in water, endows printing color paste with viscosity and plasticity, and transfers dyes, chemicals and additives to the fabric to prevent pattern infiltration. When the dye is fixed, the thickener is washed off the fabric.

Before the appearance of synthetic thickeners, natural thickeners or modified natural thickeners, such as sodium alginate, starch, cellulose and gum, were used for fabric printing. This article introduces the natural thickener - sodium alginate.

Sodium alginate is the main component of kelp and sargassum, which can be extracted from them. Alginic acid is to cut kelp or Sargassum after iodine extraction, soak it, and then convert alginate into sodium alginate with 6%~9% pure alkali solution of algae weight for dissolution. After filtering, the filtrate is bleached by bleaching solution, and then precipitated and washed with hydrochloric acid to form alginate gel, which becomes solid after drying.

In alginate, the content of polyD-mannuronic acid is generally 20%~40%; Poly-L-guronic acid, the content is 20%~40%; The alternating copolymer of two uronic acids accounts for 20%~40%. Alginic acid is not homopolymer, but it is usually expressed by the structural formula of poly-D-mannuronic acid. The molecular weight is generally 50000~185000.

From the perspective of molecular structure, compared with cellulose, alginate only replaced hydroxymethyl group with carboxyl group on the 5 carbon atoms. There are also secondary alcohol groups on the 2 and 3 carbon atoms. Because of the existence of carboxyl group, it can react with alkali to form sodium carboxylate, which is soluble in water, thus making sodium alginate negatively charged. Although sodium alginate has secondary alcohol group in the molecule, because there is a negatively charged carboxyl group, it is mutually exclusive with negatively charged reactive dyes, thus reducing the interaction between reactive dyes and secondary alcohol group. It is a suitable thickener for reactive dyes.

Alginate can be used for direct dye printing on cotton and viscose; Printing of disperse dyes on acetate, nylon and other synthetic fabrics; Printing of reducing, soluble reducing, soluble azo dyes and paints on plants, animals or synthetic fibers. It is also used for printing acid dyes on wool. It can not be used for alkaline or chrome dye printing, because there are bivalent and trivalent metal salts in the color paste. The sodium alginate paste printing has high color supply; Because of good plasticity, the outline is clear when printing fine patterns; Good penetrability and uniform color gain; Because it is soluble in water and easy to wash, the printed fabric feels soft; The paste adhering to the flowerpot and screen screen during printing is also easy to remove.

Tyson Bio is a sodium alginate manufacturer, which produces sodium alginate, potassium alginate and carrageenan in Shandong Province. Welcome new and old customers to call us for consultation.