Polymeric sizing agents

The cotton yarns sized with various polymeric sizing agents were provided by Southern Regional Research Center, U.S. Department of Agriculture. These yarns had been sized on a laboratory single-end-slasher. Portions of the sized yarns also had been subjected to a desizing process involving a boil-off with 0.5 sodium hydroxide. 

Polymeric Sizing Agents (PSA) are mainly based on styrene-acrylates, polyurethanes or styrene-maleic acid anhydride. They are either water-based dispersions or aqueous solutions. These products were developed around 1960. Since that time an increasing number of size-presses for strength improvement with starch have been installed. 

For surface sizing mostly polymeric sizing agents are used. The most important product classes are acryhc copolymer dispersions stabilised by protective colloids. The particles of the sizing agent consist of a hydrophobic polymer core and a hydrophilic shell formed out of the protective colloid. 

Textile sizing agents such as polyvinyl alcohol may also be reclaimed from hot process water. Here, both polymeric membranes and inorganic, dynamic membranes are appropriate choices. Systems based on polymeric membranes operate at lower fluxes and require less recirculation pumping, and are somewhat more economical. Plants with treatment capacities as high as 60 m3 per hour are in operation. 

Through copolymerization there can be made materials with different properties than those of either homopolymer, and thus another dimension is added to the technology. Consider, for example, styrene. Polymerized alone, it gives a good electric insulator that is molded into parts for radios, television sets, and automobiles. Copolymerization with butadiene (30%) adds toughness with acrylonitrile (20-30%) increases resistance to impact and to hydrocarbons with maleic anhydride yields a material that, on hydrolysis, is water-soluble, and is used as a dispersant and sizing agent. The copolymer in which butadiene predominates (75% butadiene, 25% styrene) is an elastomer, and since World War II has been the principal rubber substitute manufactured in the United States. 

A typical application for these filter aids is the filtration of solids from antibiotic fermentation broths, where the average particle size is 1-2 microns and solids concentration are 5-10%. Being hard to filter and often slimy, fermentation broths can also be charged with polymeric bridging agents to agglomerate the solids, thereby reducing the quantities of filter aid required. 

Most sizing problems can be related to one main problem the lack of the sizing agent, be it rosin, AKD, ASA, polymeric, or any one of the other synthetic sizes available in the paper or board. 

Chem. Descrip. Med. to high m.w. polymeric plasticizer Uses Plasticizer for adhesives (emulsion, solv., hot-melt), heat-resist, lacquers, barrier coalings (oil, fats, hydrocarbons), paints, sealants binder sizing agent for glass fibers... 

Uses Antioxidant for lubricants, rubber, waxes monomer stabilizer insecticide mfg. of dyes polymerization inhibitor for acrylic ester monomers chain transfer agent in rubber prod. polymerization control agent in food-pkg. adhesives food and feed additive treatment of food-producing animals mfg. of chlorpromazine and related antipsychotic drugs anthelmintic drug antioxidant in dry rosin size in mfg. of paper/paper-board in contact with aq./fatty foods in food-contact rubber articles for repeated use... 

Polymethacrylic acid CAS 25087-26-7 Synonyms PMAA Classification Polymer Empirical (C4He02)x Formula [CHzCCHaCOOHlx Uses Dispersant for pigments and fillers in ceramics, polymerization dispersant in boiler water treatment cement grinding aid textile soil-release finishes rayon textile sizing agent stabilizer for PVC suspension prod. vise, control agent in cosmetics Manuf./Distrib. Al co... 

Acrylic acid (ca. 1855) (propenoic acid, vinylformic acid) n. CH2=CHCOOH. A colorless, unsaturated acid, that polymerizes readily. The homopolymer is used as a thickener and textile-sizing agent and, cross-linked, as a cation-exchange resin. Acrylic-acid esters are widely used as monomers for acrylic resins. Mol wt., 72.06 mp, 14°C bp, 141.0°C Sp gr, 1.422. 

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