Spacers and Adhesives - Rear Adhesive
Overview | Rear Adhesive | Constraint relating to adhesion
REAR ADHESIVE:
The function of the rear adhesive is to ensure permanent adhesion between the keypad membrane and the substrate on which it will be installed.
Choosing the correct rear adhesive for the particular application is a critical part of the initial design cycle. This will ensure compatibility with the application surface therefore avoiding premature delamination. Depending on the surface texture, and surface tension (energy), some adhesives will perform far better than others. GGI International's sales and design teams will always inquire about the specifics of your application: What is the definition of the raw material? What is the application environment in which the assembly will be subjected to? Is the application indoors or outdoors?
- Surface energy: Surface energy is based on the wettability of a liquid on a solid, expressed in dynes/cm. Though the adhesive is not in liquid form, the same properties apply. When an adhesive is put in contact with a surface not covered with adhesive, it forms a contact angle between the adhesive and the surface. When wetting is perfect, the contact angle becomes null. In this case, the energy of adhesion is at its maximum. In fact, what characterizes the quality of adhesion is the contact angle between the solid surface and the adhesive, that is to say the capacity of the adhesive to spread on the adhesion surface. In short, the higher the surface energy of the material, the more the adhesion will be easy, because the angle of adhesion will be small and the surface of adhesion will be agressive. There are adhesives especially designed for materials with low surface energy and which reduce as much as possible the angle of adhesion.
By providing us with information relating to the surface of adhesion on which the membrane keypad user interface assembly will be applied to, GGI International will be in a position to select and recommend the adhesive most suitable to your application.