Alkali-treated bark extended tannin-aldehyde resinous adhesives
AssigneeChampion International Corporation
InventorSeymour Hartman
Life of this patent
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Abstract
Bark-extended tannin-aldehyde resinous adhesives are formed in situ as adhesives for wood products, such as plywood. Bark, in a finely divided particle form, is treated with alkali and then used as an extender by admixing the bark particles with tannin and an aldehyde co-reactant therefor. The admixture is combined as a bonding agent for the wood members to be adhered, and is formed in situ into an adhesive by subjecting the wood members to temperature and pressure conditions effective to form a bark-tannin-aldehyde resin.
Claims11
A tree-derived adhesive composition, which comprises the reaction product of an admixture of an alkali-bark pre-mix, tannin and aldehyde, said alkali-bark pre-mix being a mixture of finely divided bark particles, alkali, and water, said pre-mix being neutralized with acid to a pH in the range of approximately 5.5 to 7 pH prior to the addition of the tannin and aldehyde, said admixture of said alkali-bark pre-mix, tannin, and aldehyde occurring without an application of external heat.
A process for preparing a tree-derived adhesive composition comprising the steps of:
- preparing an alkali-bark pre-mix by admixing finely-divided wood bark and alkali, said admixture creating an exotherm;
- and
- slowly adding water to said admixture as the exotherm continues;
- neutralizing said pre-mix with acid to a pH in the range of approximately 5.5-7 pH;
- adding to said neutralized pre-mix, tannin and aldehyde;
- and
- agitating said pre-mix -- tannin aldehyde mixture until a homogeneous blend is formed;
- said adhesive composition being prepared without the application of external heat.
Dependencies are inferred from the claim text.