A. Schulman, Inc.

Wayne F Nelson

Resistance to cathodic or galvanic disbondment of plastic-metal laminates is obtained by incorporating in the metal bonding plastic material used in forming the laminate an amount of conductive carbon black effective to minimize or prevent disruption of the bond by galvanic action which otherwise would take place in the absence of the conductive carbon black. The conductive carbon black is used in a relatively high concentration, for example, between about 20 and about 40 percent, with the balance of the composition being made up of a polymeric material containing an amount effective to promote bonding between the metal and the polymeric material of an ionomeric copolymer containing about 25 to about 98.5 percent ethylenic units and between about 1.5 to about 30 percent carboxylic acid units, the major proportion of which is in the free acid form. Advantageously, two-thirds or more of the carboxylic units are in the free form and the remainder, if any, are neutralized by zinc.

Plastic-metal laminate, process, and composition

Resistance to cathodic or galvanic disbondment of plastic-metal laminates is obtained by incorporating in the metal bonding plastic material used in forming the laminate an amount of conductive carbon black effective to minimize or prevent disruption of the bond by galvanic action which otherwise would take place in the absence of the conductive carbon black. The conductive carbon black is used in a relatively high concentration, for example, between about 20 and about40 percent, with the balance of the composition being made up of a polymeric material containing an amount effective to promote bonding between the metal and the polymeric material of an ionomeric copolymer containing about 25 to about 98.5 percent ethylenic units and between about 1.5 to about 30 percent carboxylic acid units, the major proportion of which is in the free acid form. Advantageously, two-thirds or more of the carboxylic units are in the free form and the remainder, if any, are neutralized by zinc.

The disclosure relates to a modified ionomer blend which is characterized by excellent metal adhesion, good weatherability, and low gloss, consisting essentially of an intimate mixture of (1) about 20 to 60 percent of an ethylene-propylene rubber, in which ethylene is the predominant component, (2) about 40 to 80 percent of a copolymer containing ethylene units and carboxylic acid containing units, said copolymer containing between about 25 and 98.5 percent ethylene units and between about 1.5 and 30 percent carboxylic acid containing units, and said carboxylic acid units being from 10 to 100 percent neutralized with metallic ions, and (3) an effective amount up to about 10 percent of a coloring material selected from the group consisting of (1) carbon black, and (2) a pigment plus an ultraviolet stabilizer, with or without an antioxidant, and to a process in which the ionomer blend is extruded onto a metal strip which has first been cleaned with a detergent wash, rinsed with pure or deionized water, dried, heated, and passed through a crosshead die of an extruder concomitantly with the extrusion of the ionomer blend.

Growing community of inventors

Akron, OH, United States of America

Wayne F Nelson