Why are Plastics Hard to Glue?

Plastics are popular in modern product designs because they are versatile, low-cost, and provide superior performance characteristics. The flexibility of compounds like acetals, polypropylenes, and polyethylenes makes them popular with designers, but joining these parts together in a plastic assembly requires special consideration.

How to Bond Plastics That are Hard to Glue

Modern plastics are hard to glue because the compounds often lack sufficient surface tension. Using glues in plastic assemblies frequently requires a primer or promoter to alter the molecular properties of the surface to establish the required clamp load.

While this may suffice under ideal conditions, glues with superficial joints are prone to degradation because of air or water penetrating the joint.

Even with a primer or promoter, using glue as a joining method faces many challenges in assembly and manufacturing. Consider that:

Adhesives require a longer time to cure to achieve the required bond strength
The bonding depends on physical and chemical conditions that may change with aging
Glues are often hazardous and require special protective controls to avoid human exposure
Gluing plastics requires cleaning and preparing the surface before adhesion

Although bonds that use promoters and glues can overcome the challenges in clamp load, the increased cycle time required for each assembly doesn’t make them ideal in manufacturing applications. For manufacturing industries like automotive parts, medical devices, and modern electronics, you need a better solution to maintain throughput without increasing product liability.

Why Heat Staking with a Thermal Press is the Better Choice

The bonding techniques provided by a thermal press consistently perform better in manufacturing applications compared to glues. These platforms remain flexible enough to support a variety of bonding approaches including heat staking, hot bar soldering, swaging, insertion, and film/filter welding or sealing.

You can program the precise recipes you need for every assembly and include advanced bonding techniques that require heat activation of the adhesive, saving you precious curing time. To see more of the applications available from a Thermal Press solution, check out this page.

Improve the Quality of Clamp Loads for Your Plastic Assemblies with Thermal Press International

Thermal Press International is the leading provider of heat sealing and hot staking equipment. Our solutions ensure you can streamline your operations and improve product quality with consistent and repeatable joints between two or more plastic parts. With a variety of platforms available and the ability to change your tooling quickly, you can ensure each bond has the required clamp load without having to glue your plastic parts together.

Tags: heat sealing, hot staking, How to bond plastics that are hard to glue, joining plastic parts together in an assembly, using glues in plastic assemblies