摘要 |
The invention is a self-cross-linked polyvinyl butyral (PVB) binder for organic photoconductors (OPC's). The non-cross-linked form of the binder is available from Monsanto Co. in the U.S.A. as Butvar TM , and from Sekisui Chemical Co. in Japan as Slek TM . It was discovered that the PVB may be self-cross-linked by subjecting it to a thermal cure at between about 150 DEG -300 DEG C. for about 2 hours. Other ways of cross-linking, for example, e-beam, UV or X-ray radiation, may achieve results similar to those obtained with heat. No cross-linker, nor cross-linkable copolymer nor catalyst is required to accomplish the cross-linking. After self-cross-linking, the PVB has good mechanical durability and good anti-solvent characteristics. In addition, the self-cross-linked PVB's glass transition temperature (Tg) increases from about 65 DEG C. to about 170 DEG C. Also, when conventional photoconductor pigments are dispersed in the self-cross-linked PVB, they are well dispersed, and the resulting OPC's have good charge acceptance, low dark decay, and in general, good photodischarge characteristics. Also, OPC's with the self-cross-linked PVB exhibited improved adhesion, so multi-layered OPC's made according to this invention will have improved inter-layer bonding and longer economic lives.
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