| abstract |
The invention relates to a composition for enhancing the strength or sizing properties of a cellulosic fiber, comprising a) a self-emulsifying isocyanate and b) a coupling agent. The invention also relates to a kit of the composition, a process for enhancing the strength or sizing of a cellulosic fiber, products made from the process, and modified cellulosic fiber. The coupling agent and self-emulsifiable isocyanante can be added at a number of points in the paper making process. In one embodiment, the coupling agent and self-emulsifiable isocyanate are independently added to the cellulosic fiber at any point between the exit of the machine chest (5) and the screens (11) just prior to the headbox. In one embodiment, the coupling agent and selfemulsifiable isocyanate are added to the cellulosic fiber before or after the screens (11). In one embodiment, the coupling agent and self-emulsifiable isocyanate are added to the cellulosic fiber at the stuff or headbox (6). In a prefered embodiment, the self-emulsifiable isocyanate and coupling agent are added at the fan pump (8). Even more preferably, the self-emulsifiable isocyanate is added just prior to the fan pump (8) and the coupling agent just after the fan pump (8). The coupling agent and self-emulsifiable isocyanate can be added at the same point, either in separate lines or as a premixed composition, or at different points in the process. |