Patent · US Expired

Process for the preparation of polyvinyl alcohols which are soluble in cold water and have been absorbed onto pigments

US4997870A · kind A · utility

6Cited by

9References

8Claims

0Family size

Assignee

Wacker Chemie AG · DE

Inventors

Bernd Schilling · Waldshut-Tiengen, DE
Karl-Ernst Fickert · Neumarkt-Sankt Veit, DE
Joachim Schulze · Soest, DE

Key dates

Filing date	Nov 27, 1989
Grant date	Mar 5, 1991
Priority date	—
Expiry date	Nov 27, 2009

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08J2329/04
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

A process is provided for the preparation of polyvinyl alcohols absorbed onto pigments. In the process 10% to 30% strength by weight of aqueous solutions of partially hydrolyzed polyvinyl alcohols or fully or partially hydrolyzed vinyl alcohol copolymers, which are soluble in cold water, are spray-dried after the addition of 20% to 40% by weight, relative to the total solids content of the resulting suspension, of organic or inorganic pigments, preferably chalk. The invention is also directed to the pulverulent product and its use, wherein the product is distinguished by good flow capacity and an extremely low methanol content. It is suitable for use as a binder in paper coating compositions and in coatings for the surface finishing of paper and cardboard.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.