Cellulose products treated with isocyanate compositions
First Claim
1. A modified cellulose product that comprises cellulosic fibers treated with 5-30% of a polyisocyanate composition, said composition comprising a polyisocyanate at least difunctional in --NCO and 1-20% by weight of the composition being a compound selected form the group consisting of triacetin, triethyl citrate, and mixtures thereof.
3 Assignments
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Accused Products
Abstract
The invention is directed to a composition of matter useful as a paper impregnant, to the method of its use, and to the products produced by the method. Poly (diphenylmethane diisocyanate) or PMDI has been used in the past as a paper impregnant with or without propylene carbonate as a diluent. These products have generally required pressing under high pressures and at elevated temperatures. It has now been found that triacetin and/or triethyl citrate in usages up to about 20% of PMDI give superior performance in impregnated products. The modified PMDI will cure at essentially ambient conditions in times as short as 1-2 days to insoluble polyureas with low residual amounts of isocyanates and reaction byproducts such as 4,4'"'"'-diaminodiphenylmethane. The treated papers can be used in applications of which skins for sandwich panels and high strength corrugated board would be exemplary.
201 Citations
18 Claims
- 1. A modified cellulose product that comprises cellulosic fibers treated with 5-30% of a polyisocyanate composition, said composition comprising a polyisocyanate at least difunctional in --NCO and 1-20% by weight of the composition being a compound selected form the group consisting of triacetin, triethyl citrate, and mixtures thereof.
- 7. A method of making a modified cellulose product comprising treating a sheeted cellulose fiber product with 5-30% of a polyisocyanate composition, said composition comprising a polyisocyanate at least difunctional in --NCO and 1-20% by weight of the composition being a compound selected from the group consisting of triacetin, triethyl citrate, and mixtures thereof.
- 14. A corrugated board product comprising at least one linerboard adhesively bonded to a corrugated medium, at least one of said medium or linerboard being treated with 5-30% of a polyisocyanate composition, said composition comprising a polyisocyanate at least difunctional in --NCO and 1-20% by weight of the composition being a compound selected from the group consisting of triacetin, triethyl citrate, and mixtures thereof.
Specification