Methylolated kraft lignin polymer resin

4,113,675

05/752,628

December 20, 1976

A highly cross linkable methylolated kraft lignin resin for use as a high wet strength adhesive and the like, in which premethylolated kraft lignin of kraft or soda black liquor is combined with a phenolic cross linking agent, which is optionally methylolated, at a pH in the range of pH 4 to pH 7. The lignin is methylolated under alkaline conditions and then may either be acidified to provide an aqueous dispersion or dissolved in a fugitive base such as ammonium hydroxide so as to be brought into close association with the mutually soluble phenolic cross linking agent. The resin is cross linked by conventional heat curing techniques.

Clarke, Michael R. (Aylmer, CA); Dolenko, Allan J. (Ottawa, CA)

Canadian Patents and Development Limited (Ottawa, CA)

We claim

1. A process for producing a highly cross linkable methylolated kraft lignin resin which comprises reacting kraft or soda lignin under alkaline conditions with a methylolating agent to thereby produce methylolated lignin and subsequently mixing said methylolated lignin with a phenolic cross linking agent and providing a pH below 7 to produce an intimately associated resin complex of methylolated lignin and phenolic cross linking agent curable at elevated temperature.

2. A process as claimed in claim 1 wherein said kraft or soda lignin is contained in a kraft or soda process black liquor.

3. A process as claimed in claim 2 wherein the intimately associated complex forms a precipitate or separate liquid phase and is separated from residual mother liquor.

4. A process as claimed in claim 1 wherein said complex production and a subsequent curing are both carried out at a pH below about 7.

5. A process as claimed in claim 1 wherein said methylolating agent is selected from the group comprising formaldehyde, paraformaldehyde, hexamethylene tetramine, and other compounds which readily decompose to formaldehyde.

6. A process as claimed in claim 5 and wherein said phenolic cross linking agent is selected from the group comprising phenol, catechol, cresol and resorcinol monomers, alkyl and aryl substituted compounds of said monomers, and condensed said monomers with one of aldehydes and ketones.

7. A process as claimed in claim 6, wherein said phenolic cross linking agent is a phenol formaldehyde reaction product.

8. A process as claimed in claim 6, wherein said methylolated lignin and said phenolic cross linking agent are initially dissolved in a fugitive base.

9. A process as claimed in claim 8, wherein said methylolated lignin and a phenol formaldehyde reaction product are mutually dissolved in ammonium hydroxide.

10. A process as claimed in claim 2 wherein said methylolated lignin is precipitated from said black liquor by addition of acid, so as to form an acid aqueous dispersion thereof to which is added said phenolic cross linking agent to produce said intimately associated resin complex.

11. A process for producing a highly cross linked methylolated kraft lignin polymer resin which comprises: reacting an alkaline solution of kraft or soda lignin with formaldehyde to thereby produce methylolated kraft lignin, adjusting the pH of the solution to the range 5-7 uniformly mixing therewith at least 5% by weight of total resin solids of a phenol formaldehyde reaction product at a pH of 6.0-7.0 thereby producing an intimately associated resin complex, and curing said complex.

12. A process as claimed in claim 11 wherein said alkaline solution of kraft or soda lignin comprises a kraft or soda process black liquor.

13. A process for producing a highly cross linked methylolated kraft lignin polymer resin which comprises: reacting an alkaline solution of kraft or soda lignin with formaldehyde to thereby produce methylolated kraft lignin, separating said methylolated kraft lignin from said solution following precipitation with a mineral acid, dissolving said methylolated kraft lignin and a phenol formaldehyde reaction product in ammonium hydroxide as a fugitive base which dissipates sufficiently to provide acidic pH values during curing of said resin, and curing.

14. A highly cross linkable methylolated kraft lignin resin for use as a high wet strength adhesive, comprising an intimately associated resin complex of premethylolated kraft lignin with a phenolic cross linking agent, produced at a pH in the range 2-7.

15. A resin as claimed in claim 14 wherein said kraft lignin is contained in a kraft or soda process black liquor.

16. A resin as claimed in claim 14, in the form of a powder resulting from the removal of black liquor non-lignin materials.

17. A resin as claimed in claim 16 wherein said powder is dissolved in a solvent therefor.

18. A resin as claimed in claim 14 wherein said phenolic cross linking agent is selected from the group comprising phenol, catechol, cresol and resorcinol monomers, alkyl or aryl substituted compounds of said monomers and condensed said monomers with one of aldehydes and ketones.

19. A resin as claimed in claim 18 wherein said phenolic cross linking agent is a phenol formaldehyde reaction product.

20. A resin as claimed in claim 19 wherein said phenol formaldehyde reaction product is present in an amount between 5 and 80% by weight of total resin solids.

21. A composition of matter for use in a process for the production of a high wet strength adhesive, comprising a pre-methylolated kraft lignin and a phenolic cross linking agent dissolved in a fugitive base which dissipates sufficiently to provide acidic pH values during curing of said adhesive.

22. A composition of matter as claimed in claim 21 wherein said fugitive base is ammonium hydroxide.

260/175; 156/335

C08H 502; C08G 824

3090700 May 1963 Ball et al.
3185654 May 1965 Ball et al.
3454508 July 1969 Herrick et al.
3864291 February 1975 Enkvist

edspgr.04113675