For over 60 years WEVO-CHEMIE has developed, produced and sold electrical casting resins and adhesives based on polyurethane and epoxide resin. Predominantly manufacturers in the fields of the electrical/electronics industry, automobile electronics and the filter industry are supplied with these products. 

One of the special challenges in the filter industry is the adhesive bonding of filter end caps. Here very good adhesion is required even under extreme operating conditions involving, for example, prolonged exposure to oil at temperatures of about 150 °C. A further difficulty in this process is that before bonding the end caps are often slightly soiled with oily accretions. Pretreatment with plasma provides a suitable method in this case for ensuring a rapid bonding process and avoiding expensive cleaning operations on the surfaces. 

Numerous customers of WEVO-CHEMIE are very successfully employing the Openair-Plasma^® atmospheric pressure plasma developed by Plasmatreat and by this means achieving optimum adhesion of PU and epoxy adhesives to polyamide end caps. 

Another field of application for this plasma pretreatment is found in the production of automobile sensors. Special polyurethane casting resins are typically used for this purpose. Here, as a general rule, there is the risk that in plastics having a high glass fibre content or in the case of non-polar surfaces the components will be infiltrated with moisture in demanding service life tests and as a result failures will occur. To prevent this in this field also, critical surfaces have been successfully pretreated by means of Openair-Plasma^® immediately prior to the casting process.

Bonding