Daishowa Chemicals Inc.

Lori L Bushar

Stephen Y Lin

A wood preservative composition comprising a lignosulfonate copolymer and a metal salt or a combination of metal salts. The copolymer is a reaction product of lignosulfonate and acrylic monomers selected from a group of acrylic compounds of the general formula, RCH=CR.sup.1 COOH, where R is hydrogen, an alkyl or carboxyl group and R.sup.1 is hydrogen or an alkyl group, and the metal salt is a salt of sulfate, chloride, phosphate, or carbonate wherein the metal is selected from the group consisting of copper, zinc, mercury and lead. Alternatively, the composition may be a metal salt or a combination of metal salts of a lignosulfonate copolymer produced by base exchange of the corresponding calcium lignosulfonate copolymer with a metal salt or metal salts. The composition may be used, optionally, together with methylol phenol.

Wood preservative

A graft copolymer of lignin and vinylic monomer is produced by a continuous process wherein the vinylic monomer and a suitable initiator compound are continuously, but separately, fed to a solution of the lignin. The monomer is selected from a group consisting of the general formula RCH.dbd.CHR'R' where R and R' are H, or alkyl group, and R' is --COOH, --CN or --CONH.sub.2 and the initiator is hydrogen peroxide, organic peroxides or persulfates.

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Wausau, WI, United States of America

Lori L Bushar