GB1275758A - Process for the preparation of new phosphorus containing starch products, the starch products obtained and compositions making use of them - Google Patents

Abstract

1275758 Dextrin phosphate; sizing compositions H H BLATTMANN A H BLATTMANN M H TESDORPF-BLATTMANN R BLATTMANN-ROTH R A BLATTMANN H BLATTMANN S BLATTMANN [trading as BLATTMANN & CO] 19 May 1969 26531/69 Addition to 1100255 Heading C3U [Also in Division D2] Dextrin phosphate is prepared by treating starch, under heating, with an aqueous solution of an alkali metal phosphate with sufficient phosphoric acid to bring the pH of the solution below 5, in an ambient atmosphere having a lower partial pressure of oxygen than that of air at atmospheric pressure, then raising the heating temperature and further reducing the partial pressure of oxygen of the ambient atmosphere and continuing the heat treatment, and also removing water, until the dextrin phosphate so formed contains 0À3-3% by weight molecularly bound phosphorus, then cooling the mixture under reduced partial pressure of oxygen of the ambient atmosphere to avoid oxidation of the desired product until it is sufficiently cool for the dextrin phosphate so produced not to be oxidized if exposed to the air. The stability of the dextrin phosphate in aqueous solution may be improved by adding an aldehyde or aldehyde mixture to the starting mixture before heating. The product may have a solubility greater than 30% at 25‹ C., and a viscosity of 5-500 c.p.s. at a concentration of 5% by weight in water at 25‹ C. The dextrin phosphate may be used in sizing compositions for textiles and papers. The compositions may also contain a nitrogen-containing starch phosphate, a synthetic polymer such as a polyacrylate, a polyvinyl alcohol or a polyvinyl acetate or a mixture thereof or a keten dimer of formula (R-CH=C=O) 2 , wherein R is an alkyl, cycloalkyl, aryl, aralkyl or alkaryl group. The compositions may also contain an alkali metal phosphate or carbonate; phosphoric acid; a substance which forms complexes with aluminium ions such as alkali metal fluorides, NTA, EDTA, tartaric acid or citric acid or a salt of these acids; or a water-soluble polysaccharide such as carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, guar flour or an alginate. A non-ionic emulsifier may also be present.