Non-flowing silicone adhesive
Adhesive formulations are described that upon sufficient curing and drying, are not sticky or tacky at room temperature, yet can be heat bonded. The adhesives are particularly useful for use in bonding brake components together and find wide application in vehicle brake systems. When used in such systems, the adhesives do not flow in parking applications yet sufficiently dampen vibration in slowing or stopping applications to counter brake squeal. The adhesives can be provided in a tape form and used for bonding brake shims to brake pads in electronic parking brake systems.
1. A hot bond silicone adhesive consisting of, prior to curing:
(i) 100 parts by weight of a polydimethylsiloxane gum and resin with vinyl and hydride functionality;
(ii) 1-60 parts by weight of a silicone resin containing tetra(trimethysiloxy) silane;
(ii) 0-1.5 parts by weight of a silicone hydride crosslinker;
(iii) 0.1-1.6 parts by weight of a platinum based catalyst; and
(iv) an optional inhibitor;
wherein after curing, the hot bond silicone adhesive exhibits:
(i) a Quick-Stick value less than 5 N/25 mm,
(ii) a Peel Adhesion to Stainless Steel (PASS) value at 100° C. greater than 5 N/25 mm, and
(iii) an Adhesive Bleeding Test (ABT) value greater than or equal to 7,500 kgf at 200° C.; and
(iv) substantially no tack in dry form using finger pressure at room temperature.
2. The hot bond silicone adhesive of claim 1 wherein the hot bond silicone adhesive is free of fillers.
3. The hot bond silicone adhesive of claim 1 wherein the hot bond silicone adhesive exhibits an Adhesive Bleeding Test (ABT) value greater than or equal to 10,000 kgf at 200° C.
4. The hot bond silicone adhesive of claim 3 wherein the hot bond silicone adhesive exhibits an Adhesive Bleeding Test (ABT) value greater than or equal to 15,000 kgf at 200° C.
5. A hot bond silicone adhesive of claim 1 ,
wherein the hot bond silicone adhesive is addition curable; and
wherein after curing, the hot bond silicone adhesive of exhibits substantially no tack in dry form using finger pressure at room temperature.
6. The hot bond silicone adhesive of claim 5 wherein the hot bond silicone adhesive exhibits an Adhesive Bleeding Test (ABT) value greater than or equal to 10,000 kgf at 200° C.
7. The hot bond silicone adhesive of claim 6 wherein the hot bond silicone adhesive exhibits an Adhesive Bleeding Test (ABT) value greater than or equal to 15,000 kgf at 200° C.
8. The hot bond silicone adhesive of claim 5 wherein the hot bond silicone adhesive is free of fillers.
9. A transfer tape for bonding a first member to a second member, the transfer tape comprising: (i) at least one liner; and (ii) a layer of a hot bond silicone adhesive of claim 1 .
10. The transfer tape of claim 9 wherein the hot bond silicone adhesive is free of fillers.
11. The transfer tape of claim 9 further comprising a layer of hot bond silicone adhesive of claim 1 .
12. A method of producing a transfer tape for bonding one member to another member, the method comprising:
applying a hot bond silicone adhesive of claim 1 to a liner or substrate layer; and at least partially curing the hot bond silicone adhesive to form the transfer tape.
13. The method of claim 12 wherein at least partially curing the hot bond silicone adhesive is performed by heating the silicone formulation to a temperature of at least 60° C.
14. The method of claim 12 wherein at least partially curing the hot bond silicone adhesive is performed by heating the silicone formulation to a temperature of at least 100° C.
15. The method of claim 12 wherein at least partially curing the hot bond silicone adhesive is performed by heating the silicone formulation to a temperature of at least 150° C.
16. The method of claim 12 wherein the hot bond silicone adhesive is fully cured to form the transfer tape.
17. A method of bonding a first member to a second member, the method comprising:
laminating a layer of the hot bond silicone adhesive of claim 1 to a first member such that at least a portion of a face of the layer of the hot bond silicone adhesive is exposed; and bonding the second member to the exposed portion of the hot bond silicone adhesive.
18. The method of claim 17 wherein laminating the layer of the hot bond silicone adhesive to the first member is performed at room temperature.
19. The method of claim 17 wherein laminating the layer of the hot bond silicone adhesive to the first member is performed by heating the adhesive to a temperature of at least 60° C.
20. The method of claim 17 wherein laminating the layer of the hot bond silicone adhesive to the first member is performed by heating the adhesive to a temperature of at least 100° C.
21. The method of claim 17 wherein laminating the layer of the hot bond silicone adhesive to the first member is performed by heating the adhesive to a temperature of at least 125° C.
22. The method of claim 17 wherein laminating the layer of the hot bond silicone adhesive to the first member is performed by heating the adhesive to a temperature of at least 150° C.
23. The method of claim 17 wherein bonding of the second member to the layer of the hot bond silicone adhesive is performed at room temperature.
24. The method of claim 17 wherein bonding the second member to the layer of the hot bond silicone adhesive is performed by heating the adhesive to a temperature of at least 100° C.
25. The method of claim 17 wherein bonding the second member to the layer of the hot bond silicone adhesive is performed by heating the adhesive to a temperature of at least 125° C.
26. The method of claim 17 wherein bonding the second member to the layer of the hot bond silicone adhesive is performed by heating the adhesive to a temperature of at least 150° C.
27. A hot bond silicone adhesive consisting essentially of, prior to curing:
(i) 100 parts by weight of a polydimethylsiloxane gum and resin with vinyl and hydride functionality;
(ii) 1-60 parts by weight of a silicone resin containing tetra(trimethysiloxy) silane;
(ii) 0-1.5 parts by weight of a silicone hydride crosslinker;
(iii) 0.1-1.6 parts by weight of a platinum based catalyst; and
(iv) an optional inhibitor;
wherein, after curing, the cured hot bond silicone adhesive exhibits a Quick-Stick value less than 5 N/25 mm, a Peel Adhesion to Stainless Steel (PASS) value at 100° C. greater than 5 N/25 mm, an Adhesive Bleeding Test (ABT) value greater than or equal to 7,500 kgf at 200° C., and substantially no tack in dry form using finger pressure at room temperature.
28. The hot bond silicone adhesive of claim 1 wherein the hot bond silicone adhesive is an addition curing adhesive.