Male touch fastener elements
A male touch fastener product has an array of discrete fastening elements extending from a resin base. The elements are formed by molding stems and then deforming at least a rim of a distal end of each head to form an overhanging mushroom-type fastener element. Some are deformed against a hard surface to form flat fastener elements, and others are deformed against a compliant surface and form umbrella-shaped fastener elements. The fastener element heads feature particular structural relationships that enhance their performance, particularly with low-lying fibers.
1. A method of making a male touch fastener product, the method comprising
pressing moldable resin into respective molding cavities defined in a mold, thereby forming a resin layer on a surface of the mold while forming an array of spaced-apart resin projections extending from the resin layer;
stripping the formed resin layer from the surface of the mold, thereby pulling solidified resin from the cavities; and then
deforming distal ends of the projections by pressing the formed projections against a compliant outer surface of a heated roll, thereby forming from resin of each projection a fastener element comprising a stem extending from the resin layer to a head overhanging the resin layer.
2. The method of claim 1 , wherein the compliant outer surface of the heated roll comprises a coating of the heated roll.
3. The method of claim 2 , wherein the coating is of a material selected from the group consisting of silicone, elastomeric rubber, urethane, EPDM, natural rubber, SBR, Nitrile Rubber, fluoroelastomers, neoprene and Butyl Rubber.
4. The method of claim 2 , wherein the coating has a thickness of between 5 and 20 millimeters.
5. The method of claim 2 , wherein the coating has a durometer of about 60 Shore A.
6. The method of claim 1 , further comprising monitoring a temperature of the compliant outer surface, and controlling heating of the heated roll to maintain a desired surface temperature.
7. The method of claim 1 , wherein the projections comprise fastener element preforms having distal ends with rims directed away from the resin layer, with the rims having peripheries disposed farther from the resin layer than central portions of top surfaces of the preforms.
8. The method of claim 7 , wherein deforming the distal ends of the projections deforms the fastener element preforms into umbrella-shaped fastener elements.
9. The method of claim 1 , wherein deforming the distal ends comprises elastically deforming the compliant outer surface of the heated roll while plastically deforming the distal ends.
10. The method of claim 1 , wherein the projections each comprise a stem extending from the resin layer, and a head disposed on a distal end of the stem, the head overhanging the resin layer.
11. The method of claim 10 , wherein deforming the distal ends comprises at least mostly submerging the heads of the projections into an undeflected volume of the heated roll.
12. The method of claim 10 , wherein each head has a distal edge comprising multiple toes extending laterally outward and varying in shape and size about the edge, with adjacent toes having facing, free-form resin surfaces defining crevices therebetween, the crevices being narrower than the adjacent toes.
13. The method of claim 1 , wherein deforming the distal ends comprises forming flat surfaces directly above stems of the projections.
14. The method of claim 1 , wherein the projections are of polygonal cross-section.
15. The method of claim 1 , wherein the formed resin layer comprises a solid resin surface from which the projections extend.
16. The method of claim 1 , wherein the mold comprises a mold roll, the surface of the mold roll comprising a peripheral surface of the mold roll.
17. The method of claim 1 , wherein the surface of the mold is a surface of a mold screen defining the molding cavities.