How to Apply and Troubleshoot B-Stage Film Epoxy Adhesives

Resin Designs TechFilm is a product line consisting of high-performance, partially cured epoxy adhesive films. These specialized film adhesives are designed as alternatives to two-part liquid epoxies. Techfilm advantages include clean, precise bond thickness and borders, low and high-temperature resiliency, and harsh environmental conditions resistance. 

An important question arises: what makes these films different than opting for traditional adhesive coatings? Let's review the unique strengths of TechFilm adhesives and discuss how to best implement their unique application process.

What Are Film-Based Adhesives?

TechFilm products are considered b-stage adhesives, which means they are partially cured in thin film form, The curing process is then interrupted by storing, packaging, and shipping the material as frozen film. B-staged epoxy films can be superior to epoxies supplied in liquid form due to their ability to be applied cleanly and precisely to the needed locations. Their ability to be die-cut into complex shapes aids in this precision. 

Another significant advantage of Techfilm products is that they can contain thermal or electrically conductive materials when required; a leg up on liquid epoxies, which would suffer from settling and clogging issues if supplied at such high filler levels. Techfilm bonds can be fully cured with moderate heat and pressure within minutes, whereas similar liquid epoxies could take hours or even days. Our top polymer scientists designed this material for superior flow and wetting on common industrial substrates including most metals and plastics.  

How to Apply TechFilm Adhesives

TechFilm is used in a wide range of applications, including aerospace, automotive, and medical. It is also used in the manufacture of electronic devices, IC packaging, and other high-tech products. To apply TechFilm products, you will need the following materials: 

• TechFilm product 
• Substrate material 
• Pressure applicator 
• Curing oven  

Once you have gathered these essentials, you are ready to get started with the application.

4 Steps to Applying TechFilm Film Adhesives

1. Remove the TechFilm product from cold storage. Allow it to warm to room temperature. 
2. Apply the TechFilm product to the desired substrate material. 
3. Apply pressure to the bonded area using a pressure applicator. The amount of pressure required will vary depending on the thickness of the TechFilm product and the substrate material. 
4. Cure the bonded area in an oven at the specified temperature and time. 

Pressure Applicator Options: 

• Dead weights: Dead weights are one of the best ways to apply pressure to a bonded area. They should be preheated to the cure temperature before use.  Pressures from 0.1 psi to 100 psi have been used successfully.  Typically, 1-5 psi during cure works best. 
• Autoclave bag bonding: Autoclave bag bonding is a very effective way to apply pressure and heat to a bonded area. It is the best option for ensuring a void-free bond.  Bonding with dead weight or other pressure-exerting methods inside an autoclave will also reduce the size of voids. 
• Spring clips: Spring clips can provide a constant force during a cure cycle, but they are not as effective as dead weights or autoclave bag bonding. 
• Screw clamps: Screw clamps should not be used to apply pressure to a bonded area. As the adhesive flows during cure, the force applied by the screw clamps will decrease. 
• Vacuum bag bonding: Vacuum bag bonding is not recommended for curing TechFilm products. The low pressure and high temperature of a vacuum oven can cause the adhesive to volatilize.  This is because all the surfaces may not be fully wetted by the adhesive, while the void is exposed to the vacuum. However, a vacuum bag used in the application process of wetting the matting surfaces at 70 to 80°C is very helpful in producing void-free bonds 

Curing Temperature and Time: 

The curing temperature and time for TechFilm products will vary depending on the thickness of the film and the substrate material. The manufacturer's instructions should be consulted for specific recommendations. 

Troubleshooting TechFilm Adhesive Application: 

• If the bond is not strong, it may be necessary to apply more pressure or cure the bonded area for a longer time. 
• If there are voids in the bond, it may be necessary to use a different pressure applicator or cure the bonded area in an autoclave. 

Related Article: Troubleshooting Liquid Epoxy Application

Safety Considerations for Film Adhesives: 

• TechFilm products should be stored frozen, dry place before usage. 
• When working with TechFilm products, it is important to wear gloves and eye protection. 

Conclusion: 

Resin Designs TechFilm products are excellent alternatives to liquid epoxies with a number of advantages. Clean, fast, and efficient bonding of a wide variety of substrates can be accomplished with additional characteristics such as complex shape ability, and high levels of thermal or electrical conductivity possible.   

As a supplier of electronics protection polymers and coatings, Chase Corporation and our employees can help you with a comprehensive and unbiased approach to evaluating your application and process. We’ll show you how to maximize efficiency, minimize cost, and improve product reliability. Our outstanding manufacturing and technical support groups can provide your organization with reliable global supply, unmatched quality, and superior technical support.