Bonded Part with Laminated Rubber Member and Method of Making
A bonded part with a press-fit, vulcanized rubber member residing in compression between two rigid members and bonded thereto. The rubber member is a laminate with a core layer sandwiched between and bonded to two self-bonding rubber layers. The bonded part may be, for example, a vibration damper, isolator or absorber. The core layer and the self-bonding layers may have the same primary elastomer and cure system type, and the self-bonding layers have an adhesion promoter not present in the core layer. The adhesive layers may be from 0.05 to 1 mm thick or from 5% to 10% of the laminate thickness. The method includes forming a rubber core layer, curing it, applying a rubber adhesive layer on each side to form a laminate, inserting the laminate between two rigid members under compression, and post-curing to form a bonded part. The adhesive layers may be partially cured before inserting.
1 . A bonded part comprising a vulcanized rubber member residing in compression between two rigid members and bonded thereto, wherein the rubber member is a laminate comprising a rubber core layer sandwiched between and bonded to two self-bonding rubber layers.
2 . The bonded part of claim 1 in the form of vibration damper, isolator or absorber.
3 . The bonded part of claim 1 wherein the rigid members are metal members, and the amount of said compression is from 10% to 50%.
4 . The bonded part of claim 3 wherein the core layer and the self-bonding layers comprise the same primary elastomer type and the same cure system type, and said self-bonding layers comprise an adhesion promoter which is not present in said core layer.
5 . The bonded part of claim 4 wherein the rubber core layer comprises a peroxide cured elastomer composition and the self-bonding rubber layers comprise a peroxide cured elastomer composition comprising an adhesion promoter.
6 . The bonded part of claim 5 wherein the primary elastomer type is an ethylene-alpha-olefin elastomer and the adhesion promoter is a metal salt of an alpha-beta unsaturated organic acid.
7 . The bonded part of claim 1 wherein the self-bonding layers are each from about 0.05 mm to about 1 mm in thickness.
8 . The bonded part of claim 1 wherein the self-bonding layers are each from about 5% to about 10% of the total laminate thickness.
9 . The bonded part of claim 1 wherein the core comprises at least one surface with hills and valleys, and the self-bonding layer fills the valleys.
10 . A method comprising:
a) forming a rubber core layer from an elastomer composition comprising a primary elastomer and a cure system;
b) curing said core layer at least partially;
c) applying a rubber adhesive layer on each side of said core layer to form a rubber laminate;
d) inserting said rubber laminate between two rigid members where it resides under compression to form a composite article;
e) post-curing said composite article to effect a bond between the rubber adhesive layers and the rigid members to form a bonded part.
11 . The method of claim 10 wherein further comprising:
(f) curing said rubber adhesive layer no more than 70% of full cure according to ASTM D-5289 or equivalent method before said inserting.
12 . The method of claim 10 wherein the extent of said curing of said core layer is from 80% to 100% of full cure according to ASTM D-5289 or equivalent test method.
13 . The method of claim 10 wherein the extent of said curing of said core layer is substantially fully cured.
14 . The method of claim 10 wherein each adhesive layer is 0.05 mm to 1.0 mm in thickness.
15 . The method of claim 10 wherein the adhesive layers are each from about 5% to about 10% of the total laminate thickness.
16 . The method of claim 10 wherein the adhesive layer is applied under pressure and then partially cured to from 30% to 80% of full cure.
17 . The method of claim 10 wherein said applying is by extrusion coating with a self-bonding rubber composition.
18 . The method of claim 10 wherein said forming and said applying is by co-extrusion.
19 . The method of claim 10 wherein said applying is by insert molding (either injection, compression or transfer) and includes partially curing the adhesive layers no more than 70% of full cure.
20 . The method of claim 10 wherein said applying is by solution coating with a drying step which also partially cures the rubber adhesive layer no more than 70% of full cure.
21 . The method of claim 10 wherein the primary elastomers of the core and adhesive rubber layers are of same type and selected from the group consisting of ethylene-alpha-olefin elastomer, EPM, EPDM, SBR, NBR, NR, EVM, EAM, ECO, and blends thereof, and wherein the cure systems of the rubber layers are compatible and co-cure for adhesion there between; and wherein the adhesive layers comprise an adhesion promoter not present in the core layer.
22 . The method of claim 21 wherein
the core layer comprises EPDM as the primary elastomer and a peroxide cure system; and
the adhesive layer comprises EPDM as primary elastomer, a peroxide cure system, and a metal salt of an unsaturated organic acid as the adhesion promoter.
23 . The method of claim 22 wherein the rigid members are metal members.
24 . The method of claim 23 wherein said adhesive layer includes two peroxides with different cure activation temperatures at least 5° C. apart.