Molding methods, molds and products

• US 5,900,350 A
• Filed: 06/06/1996
• Issued: 05/04/1999
• Est. Priority Date: 06/06/1996
• Status: Expired due to Term

• Current Assignee: Velcro BVBA
• Original Assignee: Velcro Industries BV (Chartwell Industries Ltd)
• Inventors: Jens, Stephen C., Provost, George A., Lacey, Thomas G., Dowd, Clinton, Condon, Mark Joseph, Pollard, Samuel White, Grulke, Peter E., Van Stumpf, James
• Primary Examiner(s): Baxter, Janet C.
• Assistant Examiner(s): ASHTON, ROSEMARY E
• Application Number:
  US08/659,368
• Time in Patent Office: 1,062 Days
• Field of Search: 430/320, 430/325, 430/326, 264/400, 264/219, 264/152, 216/48, 5/216, 5/264
• US Class Current: 430/325
• CPC Class Codes: A44B 18/0049 obtained by moulding processes compression moulding or articles of indefinite length characterised by the shape of the surface B29C43/222; screen moulding B29C67/08
• CPC Class Codes: A44B 18/0061 Male or hook elements A44B18/0053 takes precedence
• CPC Class Codes: B29C 2043/465 having one or more cavities, e.g. for forming distinct products
• CPC Class Codes: B29C 33/42 characterised by the shape of the moulding surface, e.g. ribs or grooves
• CPC Class Codes: B29C 59/025 Fibrous surfaces with piles or similar fibres substantially perpendicular to the surface
• CPC Class Codes: B29L 2031/729 Hook and loop-type fasteners
• CPC Class Codes: C23F 1/02 Local etching
• CPC Class Codes: C23F 1/04 Chemical milling
• CPC Class Codes: Y10T 156/1064 Partial cutting [e.g., grooving or incising]
• 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 24/2775 having opposed structure formed from distinct filaments of diverse shape to those mating therewith
• CPC Class Codes: Y10T 24/2792 having mounting surface and filaments constructed from common piece of material
• CPC Class Codes: Y10T 428/24017 Hook or barb

Abstract

A method of manufacturing plates assembleable in a stack to provide a mold to form fastener elements includes applying a photoresist material to at least one side of the plate. The photoresist material is exposed to light. Portions of the photoresist material are removed based on the light exposure. Acid is applied to the plate, dissolving portions of the plate exposed to the acid and creating cavities.

Claims

1. A method of manufacturing plates that are assembleable in a stack to provide a mold to form a fastener product that has an array of closely-spaced hook members of desired form, the hook members being of a height less than 0.02 inch and integrally formed with a sheet form base, the plates having predetermined portions removed to form cavities of desired form in the plate, the plates being adapted to be assembled in a predetermined relationship so that the cavities define molding cavities for the array of hook members, the method comprising

applying a photoresist material to at least one side of a chemical-etchable plate;

exposing the photoresist material to light in a predetermined pattern wherein the pattern is based on said desired form of said hook members and the pattern deviates from the profile of said desired form to compensate for the shaping properties of a subsequent chemical etchant application;

removing a portion of the photoresist material which portion is determined based, at least in part, on the exposure to light through said predetermined pattern; and

applying a chemical etchant to the plate thereby dissolving the portions of the plate exposed to the chemical and creating said cavities.

2. The method of claim 1 wherein the photoresist material is a positive photoresist material and the exposure to light cures the photoresist material onto the plate, such that the photoresist material not exposed to the light is removed.

3. The method of claim 1 wherein the photoresist material is a negative photoresist material and the exposure to light burns the photoresist material, such that the photoresist material exposed to the light is removed.

4. The method of claim 1 wherein the pattern of light is determined by positioning a mask between a light source and the photoresist material.

5. The method of claim 4 wherein the mask is applied to the photoresist material.

6. The method of claim 4 wherein at least some of the cavities each have a hook shape including a tapered pedestal chamber and a crook chamber which are contiguous, the lower portion of the pedestal chamber being substantially wider then the crook chamber.

7. The method of claim 4 wherein the plate has a thickness, the thickness being about 0.006 inch.

8. The method of claim 4 wherein the cavities are defined by concave sides of the plates.

9. The method of claim 4 further comprising shaping the mask to achieve a desired cavity shape, by undersizing the mask in the region of desired concave surfaces and oversizing the mask in the region of desired convex surfaces.

10. The method of claim 9 comprising applying acid to the opposite sides of the plate for different time periods.

11. The method of claim 9 wherein the mask defines relatively sharp points for forming hook members with relatively rounded tips.

12. The method of claim 4 wherein the plate has a thickness, the thickness being about 0.006 inch or less, further comprising laminating a plurality of plates together to make a master plate.

13. The method of claim 4 wherein the mold is a molding roll and the molding cavities are hook shaped and a component of the hook shape extends in a cross machine direction.

14. The method of claim 4 wherein the mask is sized to achieve the predetermined shape of the cavities.

15. The method of claim 14 wherein the mask is oversized with respect to the cavities.

16. The method of claim 14 wherein the mask is undersized with respect to the cavities.

17. A method of molding a moldable material into a fastener element using plates manufactured in accord with claims 4 or 12 wherein at least some of the molding cavities are each defined by cavity portions in at least three adjacent plates and the hook members are formed by forcing moldable resin into the molding cavities so defined, cooling the resin, and then removing the cooled resin from the molding cavities.

18. The method of claim 1 further comprising applying photoresist material to a second side of the plate.

19. The method of claim 1 wherein the pattern defines cavities adapted to form hook members having a height of less than about 0.010 inch.

20. The method of claim 1 wherein the plate is etched to create cavities having a depth of between about 0.003 and 0.005 inch.

21. The method of claim 1 wherein the created cavities are adapted to form hook members having wedge-shaped crook tops.

23. The method of claim 1, or 22 wherein the chemical etchant is applied to the plate in a manner to etch entirely through the thickness of the plate so that at least some of the cavities extend through the plates.

24. The method of claim 23 wherein the etchant is applied to both sides of a plate in a manner cooperating to etch entirely through the thickness of the plate.

22. A method of forming cavities in the side of a mold plate adapted to be assembled with other plates in a predetermined relationship to define a mold for integrally molding an array of fastener hook members of a height less than about 0.020 inch extending from a sheet form base, the cavities defining hook member molding cavities when the plates are assembled;

the method comprising

applying a photoresist material to a side of the mold plate;

providing a compensated mask defining a shaped, pointed mask aperture corresponding to each cavity;

exposing a predetermined portion of the photoresist material to light through the mask apertures of the compensated mask;

removing a portion of the photoresist material to expose regions of the plate corresponding to the desired cavities, which portion is determined based on the exposure to light; and

applying a chemical etchant to the plate to dissolve plate material at the exposed regions to form said cavities.