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. A binder composition comprising liquid methylene diphenyl diisocyanate (MDI) and a derivative of native lignin, wherein the binder composition does not have any other liquid solvent, the derivative of native lignin has a phenolic hydroxyl content of from about 2 mmol/g to about 8 mmol/g and a polydispersity of from about 1 to about 5, wherein the composition is a homogeneous and stable liquid MDI-lignin composition.
2. The binder composition according to claim 1 wherein the derivative of native lignin further has an aliphatic hydroxyl content of from about 0.1 mmol/g to about 8 mmol/g.
3. The binder composition according to claim 1 wherein the derivative of native lignin further has an aliphatic hydroxyl content of from about 0.6 mmol/g to about 6.5 mmol/g.
4. The binder composition according to claim 1 comprising from about 0.1% to about 25%, by weight, of the derivative of native lignin.
5. The binder composition according to claim 1 comprising from about 50% to about 99%, by weight, of methylene diphenyl diisocyanate.
6. A method of producing the binder composition according to claim 1 , said method comprising:
a. providing a composition comprising the derivative of native lignin in a suitable solvent;
b. providing a resin composition comprising the liquid methylene diphenyl diisocyanate;
c. mixing the compositions of a and b; and
d. removing the solvent.
7. A method of producing a fibreboard, comprising the steps of:
a. providing fibres to a blowline;
b. providing the binder composition according to claim 1 ;
c. treating the fibres with the binder composition;
d. at least partially drying the treated fibres; and
e. pressing the treated fibres to form a fibreboard.