Releasable fastener systems and processes

• US 20040117955A1
• Filed: 01/06/2003
• Published: 06/24/2004
• Est. Priority Date: 10/19/2002
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Barvosa-Carter, William, Momoda, Leslie A., Browne, Alan L., Johnson, Nancy L., Stanford, Thomas B.
• Granted Patent: US 7,308,738 B2
• Time in Patent Office: Days
• US Class Current: 24/442
• CPC Class Codes: A41D 2300/326 using hooks and eyelets
• CPC Class Codes: A44B 18/0003 Fastener constructions A44B18/0023, A44B18/0046 take precedence
• CPC Class Codes: A44B 18/0007 in which each part has similar elements
• CPC Class Codes: A44B 18/0096 Shape memory materials
• CPC Class Codes: A44D 2203/00 Fastening by use of magnets
• CPC Class Codes: B64C 33/02 Wings; Actuating mechanisms therefor
• CPC Class Codes: C08L 2201/12 Shape memory
• CPC Class Codes: F16B 2200/77 Use of a shape-memory material
• CPC Class Codes: F16B 2200/81 Use of a material of the hooks-and-loops type
• CPC Class Codes: F16B 2200/83 Use of a magnetic material
• CPC Class Codes: F16B 5/07 by means of multiple interengaging protrusions on the surfaces, e.g. hooks, coils,
• CPC Class Codes: F16F 2224/045 magnetorheological
• CPC Class Codes: Y10T 24/27 including readily dissociable fastener having numerous, protruding, unitary filaments randomly interlocking with, and simultaneously moving towards, mating structure [e.g., hook-loop type fastener]
• CPC Class Codes: Y10T 24/2742 having filaments of varied shape or size on same mounting surface
• CPC Class Codes: Y10T 428/24017 Hook or barb

Abstract

A releasable fastener system comprises a loop portion and a hook portion. The loop portion includes a support and a loop material disposed on one side thereof. The hook portion generally includes a support and a plurality of closely spaced upstanding hook elements extending from one side thereof, wherein the plurality of hook elements comprises or incorporates a shape memory polymer. When the hook portion and loop portion are pressed together they interlock to form a releasable engagement. The resulting joint created by the engagement is relatively resistant to shear and pull forces and weak in peel strength forces. Introducing a thermal activation signal to the plurality of hook elements causes a change in shape orientation and/or flexural modulus that effectively reduces the shear and/or pull off forces in the releasable engagement. In this manner, disengagement of the releasable fastener system provides separation of the hook portion from the loop portion under controlled conditions. Also disclosed herein are processes for operating the releasable fastener system.

Claims

1. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a shape memory polymer; and

a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the plurality of hook elements and change a shape orientation and/or flexural modulus thereof to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

2. The releasable fastener system of claim 1, wherein the plurality of hook elements further comprise a conductive element.

3. The releasable fastener system of claim 2, wherein the conductive element comprises metals, metal alloys, conductive polymers, conductive epoxies, conductive ceramics, or conductive carbon.

4. The releasable fastener system of claim 2, wherein the conductive element provides the thermal activation signal to the plurality of hook elements by heat conduction or resistance heating through the conductive element.

5. The releasable fastener system of claim 1, wherein the shape memory polymer comprises polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate), polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether), ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsequioxane), polyvinylchloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, or copolymers thereof.

6. The releasable fastener system of claim 1, wherein the plurality of hook elements comprises a shape comprising a J-shaped orientation, a mushroom shape, a knob shape, a multi-tined anchor shape, a T-shape, a spiral shape, or combinations comprising at least one of the foregoing shapes.

7. The releasable fastener system of claim 1, wherein the loop material comprises a shape adapted to be engaged with the hook elements when the hook portion is pressed into face-to-face engagement with the loop portion.

8. The releasable fastener system of claim 1, wherein the shape orientation of the plurality of hook elements changes from an inverted J-shaped orientation to a substantially straightened shape orientation.

9. The releasable fastener system of claim 1, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of hook elements in an essentially straightened orientation and the temporary shape comprises an inverted J-shaped orientation.

10. The releasable fastener system of claim 1, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of hook elements in an inverted J-shaped orientation and the temporary shape comprises an essentially straightened orientation.

11. The releasable fastener system of claim 10, wherein the shape change occurs upon applying the thermal activation signal to the engaged hook and loop portion, the thermal activation signal reducing the flexural modulus properties of the plurality of hook elements and changing the shape of the plurality of hook elements to a substantially straightened shape orientation consequent to a force applied through the load of engagement.

12. A hook portion for a releasable fastener system comprising:

a support; and

a plurality of hook elements attached to the support, wherein the plurality of hook elements comprises a shape memory polymer adapted to change a shape orientation, a flexural modulus property, or a combination thereof, upon receipt of a thermal activation signal.

13. The hook portion of claim 12, wherein the shape memory polymer comprises polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate), polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether), ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsequioxane), polyvinylchloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, or copolymers thereof.

14. The hook portion of claim 12, wherein the plurality of hook elements further comprises a conductive element.

15. A releasable fastener system comprising:

a cavity portion comprising a support and a plurality of cavities disposed within the support;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a shape memory polymer and, in an unpowered state, comprises shapes complementary to the plurality of cavities; and

a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the plurality of hook elements and change a shape orientation and/or flexural modulus thereof to reduce a shear force and/or a pull-off force of an engaged hook and cavity portion.

16. The releasable fastener system of claim 15, wherein the shape memory polymer comprises polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate), polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether), ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsequioxane), polyvinylchloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, or copolymers thereof.

17. The releasable fastener system of claim 15, wherein the thermal activation signal comprises heating the shape memory polymer above a first transition temperature to effectuate a change in the shape orientation and/or flexural modulus of the plurality of hook elements.

18. The releasable fastener system of claim 15, wherein the shape memory polymer further comprises a conductive element.

19. The releasable fastener system of claim 15, wherein the shape memory polymer further comprises conductive filler.

20. A releasable fastener system comprising:

a first hook portion comprising a first support and a plurality of first hook elements disposed on a surface thereon, wherein the plurality of first hook elements comprises a shape memory polymer;

a second hook portion comprising a second support and a plurality of second hook elements disposed on a surface thereon, wherein the second hook elements comprise a shape similar to the first hook elements; and

a thermal activation device coupled to the plurality of first hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the plurality of first hook elements and change a shape orientation and/or flexural modulus thereof to reduce a shear force and/or a pull-off force of an engaged first hook and second hook portion.

21. The releasable fastener system of claim 20, wherein the shape memory polymer comprises polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate), polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether), ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsequioxane), polyvinylchloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, or copolymers thereof.

22. The releasable fastener system of claim 20, wherein the first and second hook elements comprise a shape comprising a J-shaped orientation, a knob shape, a multi-tined anchor shape, a T-shape, or combinations comprising at least one of the foregoing shapes.

23. The releasable fastener system of claim 20, wherein the shape orientation to the plurality of first hook elements changes from an T-shaped orientation to a substantially collapsed or Y-shape orientation upon receipt of the thermal activation signal.

24. The releasable fastener system of claim 20, wherein the plurality of first hook elements further comprises a conductive element.

25. The releasable fastener system of claim 24, wherein the conductive element comprises metal, metal alloys, conductive carbon, thermally conductive polymers, conductive ceramic, conductive epoxies, conductive polyaniline, conductive polypyrrole, or conductive polythiophene.

26. The releasable fastener system of claim 25, wherein the conductive element provides the thermal activation signal to the plurality of first hook elements by resistance heating through the wire.

27. The releasable fastener system of claim 20, wherein the plurality of second hook elements comprises a shape memory polymer.

28. The releasable fastener system of claim 20, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of first hook elements in a collapsed or Y-shaped orientation and the temporary shape comprises a T-shaped orientation.

29. The releasable fastener system of claim 20, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of first hook elements in a T-shaped orientation and the temporary shape comprises a collapsed or Y-shaped orientation.

30. The releasable fastener system of claim 29, wherein the shape change occurs upon applying the thermal activation signal to the engaged first hook and second hook portion, the thermal activation signal reducing the flexural modulus properties of the plurality of first hook elements and changing the shape of the plurality of hook elements to a collapsed or Y-shaped orientation consequent to a force applied through the load of engagement.

31. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a conductive element and a shape memory polymer; and

means for changing the shape orientation, the flexural modulus property, or the combination thereof of the plurality of hook elements to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

32. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a conductive element and a shape memory polymer; and

means for changing a temperature of the plurality of hook elements and the loop material upon demand to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

33. A process for operating a releasable fastener system, the process comprising:

contacting a loop portion with a hook portion to form a releasable engagement, wherein the loop portion comprises a support and a loop material disposed on a surface thereon, and wherein the hook portion comprises a support and a plurality of hook elements disposed on a surface, wherein the plurality of hook elements comprise a shape memory polymer;

maintaining constant shear and pull-off forces in the releasable engagement without introducing a thermal activation signal;

selectively introducing the thermal activation signal to the plurality of hook elements, wherein the energy signal is effective to change a shape orientation, a flexural modulus property, or a combination thereof to the plurality of hook elements; and

reducing the shear and/or pull off forces in the releasable engagement.

34. The process according to claim 33, wherein introducing the thermal activation signal comprises heating the shape memory polymer above a first transition temperature.

35. The process according to claim 33, wherein the shape memory polymer comprises polyphosphazenes, poly(vinyl alcohols), polyamides, polyester amides, poly(amino acid)s, polyanhydrides, polycarbonates, polyacrylates, polyalkylenes, polyacrylamides, polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyortho esters, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyesters, polylactides, polyglycolides, polysiloxanes, polyurethanes, polyethers, polyether amides, polyether esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly(butyl methacrylate), poly(isobutyl methacrylate), poly(hexyl methacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate) and poly(octadecyl acrylate), polystyrene, polypropylene, polyvinyl phenol, polyvinylpyrrolidone, chlorinated polybutylene, poly(octadecyl vinyl ether), ethylene vinyl acetate, polyethylene, poly(ethylene oxide)-poly(ethylene terephthalate), polyethylene/nylon (graft copolymer), polycaprolactones-polyamide (block copolymer), poly(caprolactone) dimethacrylate-n-butyl acrylate, poly(norbornyl-polyhedral oligomeric silsequioxane), polyvinylchloride, urethane/butadiene copolymers, polyurethane block copolymers, styrene-butadiene-styrene block copolymers, or copolymers thereof.

36. The process according to claim 33, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of hook elements in an essentially straightened orientation and the temporary shape comprises an inverted J-shaped orientation.

37. The process according to claim 33, wherein the shape memory polymer comprises a permanent shape and a temporary shape, wherein the permanent shape comprises a shape orientation of the plurality of hook elements in an inverted J-shaped orientation and the temporary shape comprises an essentially straightened orientation.

38. The process according to claim 37, wherein selectively introducing the the thermal activation signal to the engaged hook and loop portion reduces the flexural modulus properties of the plurality of hook elements and changes the shape of the plurality of hook elements to a substantially straightened shape orientation consequent to a force applied through the load of engagement.

39. The process according to claim 33, wherein selectively introducing the thermal activation signal to the engaged hook and loop portion changes the shape orientation of the plurality of hook elements from a T-shape orientation to an essentially straightened orientation.

40. The process according to claim 33, wherein selectively introducing the thermal activation signal to the engaged hook and loop portion changes the shape orientation of the plurality of hook elements from a J-shape orientation to a collapsed or Y-shaped orientation.

41. The process according to claim 33, wherein the plurality of hook elements further comprises a conductive element.