Bonded Part with Laminated Rubber Member and Method of Making

Abstract

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.