Touch fasteners with embedded particles
View Patent ↗A method of making a touch fastener includes continuously introducing molten resin to a pressure zone at a peripheral surface of a rotating mold roll, such that pressure in the pressure zone forces some of the resin into an array of stem cavities defined in the mold roll to form resin stems while a remainder of the resin forms a base at the roll surface, interconnecting the stems. The method includes forming engageable heads on the stems to form fastener elements and introducing a quantity of discrete, loose particles to the resin at an entrance to the pressure zone, such that the particles become part of the base.
1. A method of making a touch fastener, the method comprising:
continuously introducing molten resin to a pressure zone at a peripheral surface of a rotating mold roll, such that pressure in the pressure zone forces some of the resin into an array of stem cavities defined in the mold roll to form resin stems while a remainder of the resin forms a base at the roll surface, interconnecting the stems;
forming engageable heads on the stems to form fastener elements; and
depositing a quantity of discrete, loose particles onto the peripheral surface of a nip carrier roll that carries the particles into the pressure zone and introduces the particles to the molten resin at an entrance to the pressure zone, such that the particles become permanently bonded to resin of the base.
2. The method of claim 1 , wherein the nip carrier roll is the mold roll.
3. The method of claim 1 , wherein the nip carrier roll is a counter-rotating pressure roll, the pressure zone defined between the mold roll and the pressure roll.
4. The method of claim 1 , wherein the nip carrier roll defines particle cavities into which particles are received and are carried into the pressure zone.
5. The method of claim 1 , comprising retaining the deposited particles on the nip carrier roll by electro-static adhesion.
6. The method of claim 1 , comprising applying a liquid to the nip carrier roll, the liquid retaining the deposited particles until the deposited particles engage the liquid resin.
7. The method of claim 1 , comprising applying a tacky substance to the nip carrier roll, the tacky substance retaining the deposited particles until the deposited particles engage the liquid resin.
8. The method of claim 1 , wherein the peripheral surface of the nip carrier roll defines undulations that retain the particles on the nip carrier roll upstream of the pressure zone.
9. The method of claim 1 further comprising applying a vacuum to the peripheral surface of the nip carrier roll to retain the particles.
10. The method of claim 1 , wherein the nip carrier roll selectively carries the deposited particles on at least one particle retention region of the nip carrier roll.
11. The method of claim 10 , wherein the particle retention region defines a pattern on the roll that is transferred to the base.
12. The method of claim 1 further comprising continuously introducing a flexible substrate to the pressure zone, such that the base of resin is permanently laminated to the substrate in the pressure zone.
13. The method of claim 12 further comprising depositing the particles onto the flexible substrate, the flexible substrate causing the particles to be carried into the pressure zone to join the molten resin and become bonded to resin of the base.
14. The method of claim 1 , wherein the particles are larger than openings of the stem cavities.
15. The method of claim 1 , wherein the particles comprise resin of a melt temperature higher than a melt temperature of the molten resin.
16. The method of claim 1 , wherein the particles comprise colorant.
17. The method of claim 1 , wherein the particles comprise carbon black.
18. The method of claim 1 , wherein the particles comprise a reflective material.