| abstract |
Polymers reactive towards free amino groups, such as polyamides, polyureas, polyurethanes or polyesters, are provided with durable modified properties by being brought into contact with an additive polymeric material which (a) is compatible with the polymer being treated, (b) contains a plurality of oxyalkylene groups effective to impart to the modified polymer improved properties such as reduced static propensity, modified dyeability, or greater water absorbency; and (c) has one or more reactive sites, in the form of a pendant free primary amino group or potential primary amino group, blocked by the dehydration of an aldehyde or a ketone with the amine, which in either case affords the capability in proper circumstances of attaching the modifying polymeric material to the polymer being treated by a covalent chemical bond. Suitable modifying polymers are made by reacting a diamino or higher amino compound with a proportion of an aldehyde or ketone sufficient to block at least some of the amino groups present, oxyalkylating the blocked starting material through a surviving amino group to an extent capable of affording the desired properties, and if desired, cross-linking or chain-extending the resulting material to obtain a substance of increased molecular weight. Modifying polymers so made may be used as such (i.e., in the alehyde- or ketone-blocked form) for treatment of the reactable polymer to be modified, either by blending into a melt or by surface treatment of freshly produced fiber or sheet material. The formation of free amino groups in the modifying polymer can occur in situ when the modified polymer is exposed to water under suitable conditions. The modifying polymer may also be used in a free amino form generated by hydrolyzing before bringing it into contact with the polymer to be modified. Novel treated polymers are thus produced which display modified properties which are retained despite repeated washings and/or long-continued use. |