Solutions to common problems with low-temperature curing adhesives.

I. Viscosity Thickening

Low-temperature curing adhesives, also known as one-component low-temperature epoxy adhesives, have been the subject of several customer inquiries regarding storage issues.  Some users reported that the adhesive thickened significantly after only 10 days of storage. The manufacturer insisted that the problem stemmed from improper storage, while the users required stable viscosity for a storage period exceeding two months.  After communicating with the users, it became clear that storage was not the issue. The problem likely lies in the poor stability of the adhesive's additives. Although the product passed quality control tests immediately after production, its performance after stabilization did not meet user requirements. This resulted in repeated instances of viscosity thickening during short-term storage, a problem that remained unresolved.  We recommend switching to a professional manufacturer, as this is a technical issue that cannot be easily resolved.

II. Crystallization Phenomenon

Crystallization in low-temperature epoxy adhesives is primarily caused by the reaction of the curing agent with water and CO2 in the air, forming ammonium salts and resulting in crystal-like structures.  The question then arises: how does the curing agent in the adhesive come into contact with moisture and carbon dioxide? This indicates a change in the airtightness of the packaging. This is why we advise users to use the entire contents of the package as soon as possible after opening, as it's difficult to determine if the packaging has been compromised during use, posing a constant risk. Therefore, maintaining the airtightness and stability of the packaging throughout its shelf life is crucial to prevent crystallization.

III. Curing Problems

What are the symptoms of curing problems? Currently, we have only encountered two issues related to curing: first, users reported insufficient hardness after baking the adhesive; second, a decrease in adhesive strength. Both are due to insufficient curing strength, which is related to the actual baking temperature and time.  We recommend that users use a standard thermometer to verify the temperature of the baking oven before setting the temperature.  We also suggest paying close attention to cleaning the bonding surface and promptly drying any condensation that forms during the warming process. These measures can help prevent curing problems to a certain extent.