Foam adhesion promotion
Methods for forming a TPE-skinned composite include forming a skin layer having at least one surface and having a thermoplastic elastomer and an adhesive promoting agent; providing a foam layer; and forming the foam layer onto the said surface of the skin layer to form the TPE-skinned composite. Optional additives such as an organo-silane compound may be added to further improve the adhesion between the skin layer and the foam. The present disclosure also provides a TPE-skinned composite including a skin layer having a thermoplastic elastomer present in an amount of greater than 90 wt. %; and an adhesive promoting agent present in an amount of from 0.5 wt. % to 10 wt. % based upon the total weight of the skin layer.
1. A method for forming a thermoplastic elastomer (TPE)-skinned composite comprising the steps of:
a) forming a skin layer having at least one surface comprising:
(i) a thermoplastic elastomer; and
(ii) an adhesive promoting agent;
b) providing a foam layer forming mixture on the at least one surface of the skin layer; and
c) forming a foam layer on the at least one surface of the skin layer to form the TPE-skinned composite.
2. The method of claim 1 , wherein the skin layer comprises the adhesive promoting agent in an amount of 0.5 wt. % to 10 wt. % based upon the total weight of the skin layer.
3. The method of claim 1 , wherein the skin layer comprises the thermoplastic elastomer in an amount of equal to or greater than 90 wt. % based upon the total weight of the skin layer.
4. The method of claim 1 wherein the adhesive promoting agent is a diethanol amine amide (DEAA) having the following structure:
wherein R is a hydrocarbon chain, saturated or unsaturated, containing 6-18 carbon atoms.
5. The method of claim 1 , wherein the skin layer has a thickness of 0.5 mm to 2.5 mm.
6. The method of claim 4 , wherein the adhesive promoting agent further comprises an organo-silane compound.
7. The method of claim 4 , wherein the DEAA is present in the range of 0.5 wt. % to 5.0 wt. % based upon the total weight of the skin layer.
8. The method of claim 6 , wherein the organo-silane compound is present in the range of from 0.05 wt. % to 5.0 wt. % based upon the total weight of the skin layer.
9. The method of claim 6 , wherein the organo-silane compound contains one or more carbon-silicon bonds and wherein the organo-silane compound has a molecular weight of less than or equal to 1000 g/mol.
10. The method of claim 6 , wherein the organo-silane compound has the following structure:
11. The method of claim 1 , wherein the thermoplastic elastomer has at least one glass transition temperature below 25° C., has an elongation of at least 50% as measured according to ISO 37, and has a tensile strength of at least 4 MPa as measured according to ASTM D412.
12. The method of claim 1 , further including at least one of the following:
the thermoplastic elastomer and the adhesive promoting agent are mixed and extruded to form pellets prior to forming the skin layer; or
the thermoplastic elastomer is extruded and formed into pellets and then combined with the adhesive promoting agent prior to forming the skin layer.
13. The method of claim 12 , wherein the pellets are cryo-ground to form a cryo-ground powder having a particle size distribution average of 200 μm to 1600 μm.
14. The method of claim 13 , wherein the cryo-ground powder is combined with an organo-silane compound to form a silane-coated powder.
15. The method of claim 12 , wherein the pellets have a diameter of 2.0 to 3.0 mm and a bulk density of 20.0 lbs/ft 3 to 30.0 lbs/ft 3 .
16. The method of claim 1 , wherein the thermoplastic elastomer is selected from a group consisting of a thermoplastic polyolefin formulation (TPE-O), a styrenic block copolymer formulation (TPE-S), a polyester or copolyester formulation (TPE-E), a thermoplastic vulcanizate (TPE-V), or a polyurethane formulation (TPE-U) or a mixture of one or more thermoplastic elastomer formulations.
17. The method of claim 1 , wherein the foam layer has a thickness in the range of 3.0 mm to 8.0 mm.
18. The method of claim 1 , wherein step a) further comprises treating the skin layer by flaming the at least one surface to produce a flame treated skin layer.
19. The method of claim 1 , wherein the skin layer and the foam layer form a foam-skin bond wherein the foam-skin bond demonstrates a cohesive failure of at least 50% and wherein the pull force for the cohesive failure is in the range of 175 Newtons/meter to 250 Newtons/meter measured according to ASTM D 6862.
20. A method for forming a thermoplastic elastomer (TPE)-skinned composite comprising the steps of:
a) forming a skin layer having at least one surface comprising:
(i) a thermoplastic elastomer wherein the thermoplastic elastomer has at least one glass transition temperature below 25° C., has an elongation of at least 50% as measured according to ISO 37, and has a tensile strength of at least 4 MPa as measured according to ASTM D412; and
(ii) an adhesive promoting agent wherein said adhesive promoting agent comprises diethanol amine amide (DEAA) having the following structure:
wherein R is a hydrocarbon chain, saturated or unsaturated, containing 6-18 carbon atoms wherein DEAA is present at a level of 0.5 wt. % to 5.0 wt. % based upon the total weight of the skin layer;
b) providing a foam layer forming mixture on the at least one surface of the skin layer;
c) forming a foam layer on the at least one surface of the skin layer to form the TPE-skinned composite.