Reworkable adhesive tape for joining device structures

Patent metadata

Field	Value
Publication number	US-9815259-B2
Application number	US-201414334416-A
Country	US
Kind code	B2
Filing date	Jul 17, 2014
Priority date	Nov 18, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

Double-sided reworkable pressure sensitive adhesive tape joins electronic device structures. The reworkable pressure sensitive adhesive tape has a pair of polymer carrier layers that are attached to each other using a thermoplastic adhesive. Opposing outer surfaces of the carrier layers are coated with pressure sensitive adhesive. The thermoplastic material that is used in attaching the carriers to each has a softening temperature that allows the thermoplastic material to be softened without significantly softening the carrier layers. When the thermoplastic material is softened, the structures that have been joined using the tape may be separated from each other. This divides the tape into two tape remnants. After cooling the tape remnants to restore cohesive strength to the pressure sensitive adhesive, the tape remnants can be cleanly peeled away from the structures. Additional reworkable tape may then be used to reattach the structures.

First claim

What is claimed is:

1. Reworkable adhesive tape, comprising:
a first carrier comprising a first flexible polymer layer;
a second carrier comprising a second flexible polymer layer;
a thermoplastic adhesive that attaches the first carrier to the second carrier, wherein the thermoplastic adhesive has a softening temperature of 50-120° C., and wherein the first and second flexible polymer layers are formed from a polymer that does not soften at temperatures below the softening temperature of the thermoplastic adhesive;
a first layer of adhesive on the first carrier; and
a second layer of adhesive on the second carrier.

2. The reworkable adhesive tape defined in claim 1 wherein the first and second layers of adhesive are pressure sensitive adhesive layers.

3. The reworkable adhesive tape defined in claim 2 further comprising first and second release liners coupled to the first and second pressure sensitive adhesive layers.

4. The reworkable adhesive tape defined in claim 1 wherein the first carrier has a protruding tab.

5. The reworkable adhesive tape defined in claim 1 wherein the first and second flexible polymer layers are polyester films.

6. The reworkable adhesive tape defined in claim 1 wherein the thermoplastic adhesive comprises polycarbonate.

7. The reworkable adhesive tape defined in claim 6 wherein the thermoplastic adhesive is elastomeric.

8. The reworkable adhesive tape defined in claim 1 wherein the first and second carriers, the thermoplastic adhesive, and the first and second layers of adhesive exhibit a temperature gradient when heated.

9. A method, comprising:
attaching first and second electronic device structures together using double-sided reworkable pressure sensitive adhesive tape having first and second flexible polymer carrier films each having a thickness of 2-50 microns, having a thermoplastic adhesive that attaches the first and second flexible polymer carrier films together, having a first pressure sensitive adhesive layer on the first flexible polymer carrier film, and having a second pressure sensitive adhesive layer on the second flexible polymer carrier film;
heating the reworkable pressure sensitive adhesive tape to soften the thermoplastic adhesive; and
separating the first and second electronic device structures by pulling apart the tape while the thermoplastic adhesive is softened so that the reworkable pressure sensitive adhesive tape divides along the thermoplastic adhesive into first and second reworkable pressure sensitive adhesive tape remnants.

10. The method defined in claim 9 wherein attaching the first and second electronic device structures together comprises pressing together the first and second electronic device structures.

11. The method defined in claim 10 wherein heating the reworkable pressure sensitive adhesive tape comprises applying localized heat to the reworkable pressure sensitive adhesive tape using equipment selected from the group consisting of: infrared heating equipment and inductive heating equipment.

12. The method defined in claim 11 wherein the first electronic device structure is a display cover layer, wherein the second electronic device structure is an electronic device housing, and wherein heating the reworkable pressure sensitive adhesive tape comprises creating a temperature gradient so that the display cover layer is hotter than the electronic device housing while the thermoplastic adhesive is being softened.

13. The method defined in claim 9 further comprising:
cooling at least the first reworkable pressure sensitive adhesive tape remnant to restore cohesive strength to the first pressure sensitive adhesive layer after heating the reworkable pressure sensitive adhesive tape.

14. The method defined in claim 13 further comprising cleanly peeling at least the first reworkable pressure sensitive adhesive tape remnant from the first electronic device structure after cooling the first reworkable pressure sensitive adhesive tape remnant.

15. The method defined in claim 14 further comprising reattaching the first and second electronic device structures together with additional reworkable pressure sensitive adhesive tape.

16. Apparatus, comprising:
reworkable pressure sensitive adhesive tape having first and second flexible polymer carrier films each having a thickness of 2-50 microns, a thermoplastic adhesive that attaches the first flexible polymer carrier film to the second flexible polymer carrier film, a first pressure sensitive adhesive layer on the first flexible polymer carrier film, and a second pressure sensitive adhesive layer on the second flexible polymer carrier film, wherein the thermoplastic adhesive has a softening temperature and wherein the first and second polymer carrier films are formed from a polymer that does not soften at temperatures below the softening temperature of the thermoplastic adhesive;
a first electronic device structure; and
a second electronic device structure that is attached to the first electronic device structure by the reworkable pressure sensitive adhesive tape.

17. The apparatus defined in claim 16 wherein the first electronic device structure comprises a display cover layer.

18. The apparatus defined in claim 16 wherein the second electronic device structure comprises an electronic device housing.

19. The apparatus defined in claim 16 wherein at least the first flexible polymer carrier film has a tab that protrudes from between the first and second electronic device structures.

20. The apparatus defined in claim 16 wherein the softening temperature is 80-100° C.

Assignees

• Apple Inc

Inventors

• Krogdahl James R

Classifications

• B32B2250/02

  2 layers · CPC title

• B32B27/08 Primary

  of synthetic resin · CPC title

• Y10T428/2848

  Three or more layers · CPC title

• C09J2201/162

  Chemistry & Metallurgy · mapped topic

• C09J2201/606

  Chemistry & Metallurgy · mapped topic