| 摘要 |
Conventional polyvinyl alcohol envelopes will not readily dissolve in wash water which has a significant borate concentration and a pH frequently encountered in wash liquors. Herein, such films are rendered sufficiently soluble in such solutions. In the preferred embodiment this is done by utilizing a polyvinyl alcohol film wherein at least a portion of the polyvinyl alcohol has a number average molecular weight below about 50,000, or a polyvinyl alcohol film containing a polyhydroxy compound having a binding constant with borate of at least about 800M-2, or utilizing a polyvinyl alcohol film having an acid having an acid dissociation constant of 10-9M or larger; or a polyvinyl alcohol film containing mixtures thereof.
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