Water-soluble acrylamide/acrylic acid polymers and their use as dry strength additives for paper
US5543446A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 23, 1994 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Nov 23, 2014 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H21/18
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A water-soluble terpolymer for use as a dry strength additive for paper consists essentially of the following units: (a) (meth)acrylamide, (b) an ethylenically unsaturated, aliphatic carboxylic acid or a salt thereof, and (c) a water-soluble, polyvinyl monomer, wherein (c) comprises <0.07 mole % based on total monomers; a 1% solution of the terpolymer is capable of passing through a 200 mesh screen substantially without retention of polymer solids, and the terpolymer has a reduced specific viscosity of about 3.0 deciliters/g or less. The process for preparing the polymer includes the step of continuously adding both components of a redox initiator at a controlled rate to provide better control of polymerization and heat evolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.