Filamentary nonwoven bandage fabric
View Patent ↗In order to produce a nonwoven fabric having elastomeric properties spun filaments ( 1 ), consisting preferably (but not essentially) of cellulose material such as cellulose acetate or solvent spun rayon, not in yarn formats, are corrugated or crimped in an overfeed process, as in stuffer box ( 6 ), into stabilized three dimensional batts. A proportion of filaments ( 3 ) of a thermal memory material, such as modified polyester, in a stretched format are included. The resulting batt is then subjected to controlled hydroentangling and a controlled heat treatment to yield three dimensional nonwoven fabrics with elastomeric properties due to contraction of the stretched filaments. Elastomeric memory material activated to shrink by ultrasonic treatment may be used in place of thermal memory material. The elastomeric properties can be adjusted to suit end-use requirements and applications are envisaged in the medical and hygiene areas.
1. A method of production of non-woven fabric having elastomeric properties comprising the steps of:
including a proportion of shrinkable filaments of an elastomeric memory material in a substantially parallel array of spun filaments of nonelastomeric material;
corrugating and compacting the resulting filament assembly by means of an overfeed process to form a batt; and
subjecting this batt to a hydroentangling operation followed by controlled heat or controlled ultrasonic treatment to shrink the filaments of elastomeric memory material.
2. A method according to claim 1 including a further intermediate step, following formation of the compacted batt, of light bonding of filaments therein by ultrasonic or thermal point bonding techniques or by hydroentanglement at low water pressure.
3. A method according to claim 1 including a further step of embossing the batt, after the elastomeric filaments therein have been shrunk, by thermal or ultrasonic bonding techniques.
4. A method according to claim 1 wherein, prior to the hydroentangling operation, two or more batts are combined as layers or wherein a batt is combined with a layer of a different material.
5. A method according to claim 1 wherein the non-elastomeric filaments comprise cellulose acetate or solvent spun rayon or a combination of these materials.
6. A method according to claim 1 wherein the non-elastomeric filaments include polyesters, polyolefins or polyamides.
7. A method according to claim 1 wherein the elastomeric filaments are modified polyester filaments.
8. A method according to claim 1 wherein the non-elastomeric filaments include alginate filaments.