Abstract This disclosure relates to bonding a propylene polymer article, such as a removable closure member for a container, to a metal surface, such as the metal end portion of the container, which contains an opening for removal of the contents of the container. The metal surface is first coated with a thermosetting enamel coating composition. Next there is applied to the enamel coated surface a heat activatable adhesion promoting layer containing a carboxyl modified polypropylene resin having a particle size of less than 5 microns. The propylene polymer article is heat sealed to the carboxyl modified polypropylene containing coated surface and the resultant assembly is then immediately cooled to ambient temperature.
The process of claim 1 wherein the carboxyl modified polypropylene resin contains about 0.05 percent to about 5 percent carboxyl groups.
Claim 2
Dependent Claim
12 words
The process of claim 1 wherein the unsaturated anhydride is maleic anhydride.
Claim 3
Dependent Claim
21 words
The process of claim 1 wherein the carboxyl modified polypropylene resin has a particle size ranging from 0.1 to 3 microns.
Claim 4
Dependent Claim
32 words
The process of claim 1 wherein the bond promoting layer is an admixture of a carboxyl modified polypropylene resin and a polypropylene resin, both having a particle size less than 5 microns.
Claim 5
Dependent Claim
11 words
The process of claim 1 wherein the propylene polymer is polypropylene.
Claim 6
Dependent Claim
13 words
The process of claim 1 wherein the propylene polymer is a propylene/ethylene copolymer.