Glyoxalated lignin compositions
OwnerAntonio PIZZI, Bruno MARCOCCIA +1inventors
InventorsAntonio PIZZI, Bruno MARCOCCIA, Shabnam SANAEI
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Abstract
This disclosure includes adhesive compositions comprising lignin, as well as methods of making such adhesive compositions, methods of making glyoxalated lignin or glyoxalating lignin-fiber mixtures, particularly glyoxalated kraft lignin, and methods of making lignocellulosic composite products including the present adhesive compositions.
Claims46
An adhesive composition comprising 10 to 80 total weight percent of a lignin component, 10 to 50 total weight percent of a solvent, and 5 to 60 total weight percent of a resin component.
A process for making a tannin-glyoxalated lignin composition comprising:
- (a) dissolving tannin in water to a 45 weight percent and adding NaOH to adjust the pH of the tannin solution to about 10;
- (b) mixing the tannin solution with 6% hexamethylenetetramine (hexamine) and a glyoxalated lignin solution to form a tannin-glyoxalated lignin composition.
A tannin-glyoxalated lignin adhesive composition comprising 10 to 90 total weight percent lignin component and 10 to 90 total weight percent tannin solids.
A cold-set lignin-resorcinol-formaldehyde adhesive comprising 10 to 80 total weight percent lignin component, 0 to 50 total weight percent solvent, and 5 to 70 total weight percent resorcinol-formaldehyde resin.
A method for glyoxalating kraft lignin or lignin-fiber mixture comprising:
- dissolving kraft lignin or lignin-fiber mixture in an aqueous sodium hydroxide solution having a pH of between 8 and 13, thereby forming a kraft lignin solution;
- adding an aqueous glyoxal solution of between 10 to 50% glyoxal to the kraft lignin solution, thereby forming a reaction mixture having a glyoxal-to-kraft lignin or glyoxal-to-lignin-fiber mixture ratio of 1:1 to 1:13;
- incubating the reaction solution at between 40 to 100° C.
A method for making a cold-set lignin-resorcinol-formaldehyde adhesive comprising
- preparing a kraft lignin/tetrahydrofuran solution comprising about 30 total weight percent kraft lignin, about 60 total weight percent tetrahydrofuran (THF), and about 8 total weight percent HCl;
- reacting the kraft lignin/tetrahydrofuran solution with approximately 5.5 weight percent paraformaldehyde powder relative to the kraft lignin/tetrahydrofuran solution at a temperature of 60° C. forming a kraft/lignin/paraformaldehyde product;
- adding 12 to 16 weight percent of resorcinol relative to the kraft/lignin/paraformaldehyde product, thereby forming a kraft lignin/resorcinol mixture, and incubating the kraft lignin/resorcinol mixture at 25° C. and adjusting the pH to 9.5 to 11.25;
- adjusting the solids content of the kraft lignin/resorcinol mixture to a desired percentage by diluting the kraft lignin/resorcinol mixture in methanol.
Dependencies are inferred from the claim text.