Binder compositions comprising lignin derivatives
The present disclosure provides an adhesive composition comprising derivatives of native lignin and an isocyanate-based binder such as methylene diphenyl diisocyanate. The present compositions may further comprise formaldehyde-based resins such as PF, UF, and MF. While not wishing to be bound by theory, it is believed that incorporating derivatives of native lignin in isocyanate compositions will reduce incidence of pre-curing.
1. An adhesive system comprising:
(a) a resin composition comprising a mixture of at least about 30% by weight of a phenol-formaldehyde resin and at least about 30% by weight of a derivative of native lignin; and
(b) a liquid isocyanate-based binder, wherein the adhesive system does not have any other liquid solvent.
2. The system according to claim 1 , wherein the system comprises at least about 35% by weight of the derivative of native lignin.
3. The system according to claim 1 , wherein the derivative of the native lignin has an ethoxy content of 0.45 mmol/g or greater.
4. The system according to claim 1 , wherein the isocyanate-based binder comprises methylene diphenyl diisocyanate.
5. The system according to claim 1 , wherein the isocyanate-based binder comprises methylene diphenyl diisocyanate and a second derivative of native lignin.
6. The system according to claim 5 , wherein the second derivative of native lignin of the isocyanate-based binder has an aliphatic hydroxyl content of from about 0.6 mmol/g to about 6.5 mmol/g.
7. A method of producing a fibreboard, the method comprising:
(a) providing fibres to a blowline;
(b) providing the adhesive system according to claim 1 ;
(c) treating the fibres with the adhesive system;
(d) pressing the treated fibres to form the fibreboard.
8. The method according to claim 7 , wherein the treated fibres are at least partially dried prior to pressing the treated fibres to form the fibreboard.
9. The method according to claim 7 , wherein the fibreboard is selected from the group consisting of a low density fibreboard, a medium density fibreboard, a high density fibreboard, a strawboard, and agricultural fibre/particle board, an oriented strand board, a particle board, a wood fibre insulation board, and a polyurethane board.
10. The system according to claim 1 , wherein the derivative of native lignin has a phenolic hydroxyl content of from about 2 mmol/g to about 8 mmol/g.
11. The system according to claim 10 , wherein the derivative of native lignin further has a polydispersity of from about 1 to about 5.
12. The system according to claim 1 , wherein the derivative of native lignin further has a polydispersity of from about 1 to about 5.
13. The system according to claim 1 , wherein the derivative of native lignin has an aliphatic hydroxyl content of from about 0.1 mmol/g to about 8 mmol/g.
14. The system according to claim 13 , wherein the aliphatic hydroxyl content is from about 0.6 mmol/g to about 6.5 mmol/g.
15. The system according to claim 1 , wherein the derivative of native lignin has an alkoxy content of from 0.001 mmol/g to 2 mmol/g.