Significance and Use

The force required to separate a metallic coating from its plastic substrate is determined by the interaction of several factors: the generic type and quality of the plastic molding compound, the molding process, the process used to prepare the substrate for electroplating, and the thickness and mechanical properties of the metallic coating. By holding all others constant, the effect on the peel strength by a change in any one of the above listed factors may be noted. Routine use of the test in a production operation can detect changes in any of the above listed factors.

The peel test values do not directly correlate to the adhesion of metallic coatings on the actual product.

When the peel test is used to monitor the coating process, a large number of plaques should be molded at one time from a same batch of molding compound used in the production moldings to minimize the effects on the measurements of variations in the plastic and the molding process.

1. Scope

1.1 This test method gives two procedures for measuring the force required to peel a metallic coating from a plastic substrate. One procedure (Procedure A) utilizes a universal testing machine and yields reproducible measurements that can be used in research and development, in quality control and product acceptance, in the description of material and process characteristics, and in communications. The other procedure (Procedure B) utilizes an indicating force instrument that is less accurate and that is sensitive to operator technique. It is suitable for process control use.

1.2 The tests are performed on standard molded plaques. This method does not cover the testing of production electroplated parts.

1.3 The tests do not necessarily measure the adhesion of a metallic coating to a plastic substrate because in properly prepared test specimens, separation usually occurs in the plastic just beneath the coating-substrate interface rather than at the interface. It does, however, reflect the degree that the process is controlled.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

E4 Practices for Force Verification of Testing Machines

Keywords

electroplated plastic; peel strength test; Coating adhesion; Electrodeposited plastic coatings; Electroplated coatings; Electroplated plastics; Peel strength tests;

ICS Code

ICS Number Code 25.220.40 (Metallic coatings)

DOI: 10.1520/B0533-85R09

ASTM International is a member of CrossRef.

ASTM B533