There are many different types of industrial adhesives used in bonding various materials and substrates such as vinyl, metal, polymers or fiber composite products manufactured in the automotive industry including clutch pads, brake shoes and gasket material products. Reliable adhesion in manufacturing these products is mandatory for product performance, quality and ultimately end-user safety. Automotive OEMs have high quality standards for their suppliers, when problems occur it is mandatory to find the root cause and quickly correct adhesive bonding failures.
Causes of inconsistencies or failure in adhesive bonding are numerous. An experienced chemical and coatings manufacturer will follow a meticulous checklist to determine the root cause and provide a solution. The first thing to do is to explore the adhesive bonding mechanism itself and to evaluate the three regions, or areas, that failure can occur in the adhesive-bonded joint (ABJ). These include:
1) Adhesion to the substrate
2) Cohesion of the adhesive itself
3) First ply surface of substrate adjacent to the adhesive
Experienced industrial adhesive manufacturers understand how to evaluate both the adhesion and cohesion properties. Adhesion failures occur when the adhesive appears to have separated from the surface, failing to attach robustly to the substrate. A failure with cohesion occurs when the industrial adhesive itself separates, splits or fractures with adhesive still attached on each substrate. Let’s explore some of the causes for adhesion failure now, and check our next article on troubleshooting for cohesion failure.
Causes of Adhesion Failure
Here are some of the most common causes and possible culprits contributing to adhesion failure:
- Inadequate or poor surface treatment and preparation – under or over abrading or other surface treatment inconsistencies can lead to a low surface free energy value resulting in poor adhesion.
- Incorrect selection of adhesive – improperly selecting an adhesive without the proper wetting ability and the high surface tension value to keep the adhesive bound could result in failure.
- Contamination or moisture on the surface of the substrate – exposure to environmental contaminants during the manufacturing process or improper storage of substrates and/or adhesives can lead to contamination and moisture.
These are just a few of the more common causes of adhesion failure. Universal Chemicals and Coatings, UNICHEM, offers product and process analysis to dive deeper into adhesion failures and provide reliable, robust solutions. Additional factors to consider could be the release of oligomers during the molding process or excessive open-time or manufacturing processes that could contribute to failure.
UNICHEM supports manufacturers in a wide range of industries to troubleshoot adhesion failures and provide long-lasting solutions. With more than 50 years of expertise in adhesive technology and polymer chemistry, our industrial adhesives offer both product and process improvements for overall cost-saving efficiencies. Contact us to learn how to improve your application with stronger bonding, wider latitudes, and lower application costs.