Weicon Primer P 400 is a primer used in surface preparation before bonding low surface energy and non-absorbent plastics. It is specifically developed to improve the adhesion of subsequent adhesive applications on difficult-to-bond surfaces such as PE, PP, TPE, and EPDM. The product is a rubber-based pre-treatment chemical in liquid form containing solvent and chlorine, and it has a yellowish transparent appearance. The manufacturer is WEICON GmbH & Co. KG, based in Germany.

Technical structure and performance of Weicon Primer P 400
This primer leaves behind a thin film-forming pre-treatment layer to improve bonding performance on low surface energy plastics. Official technical data states that its density is approximately 0.8 g/cm³, while consumption ranges from 20 to 60 ml/m² depending on the surface. The current technical data sheet recommends a processing temperature between +15 °C and +35 °C, and the adhesive must be applied within no later than 1 hour after the primer has been applied. Therefore, the product is not the main material that directly provides bonding strength in the process, but rather a process-supporting chemical that optimizes surface preparation.

Application method and process control
Before application, the surface must be dry, clean, dust-free, and free from grease. Primer P 400 should be shaken before use and applied in a thin layer with the help of a clean cloth. The recommended waiting, or flash-off, time is at least 10 minutes and at most 1 hour; if this window is exceeded, the surface should be cleaned again and re-primed. For unknown plastic types or specially formulated parts, a compatibility test must always be carried out before serial application.

Compatible surfaces and system integration
Weicon P 400 is specifically designed for polyolefin-based plastics and certain elastomer surfaces. Technical documentation explicitly mentions PE, PP, TPE, and EPDM, while also indicating that the product can be used with certain WEICON urethane systems, Easy-Mix PU 90 and PU 240, as well as with selected one-component adhesive and sealing products excluding silicone. This makes it possible to use the product as a process aid in industries such as automotive supply, plastic part assembly, white goods components, cable and sealing systems, and tank and enclosure manufacturing. Especially in adhesive assembly of low surface energy plastic parts, it helps provide a more controlled application process by reducing the need for additional mechanical surface treatment.

Application areas, advantages, and safety framework
The product stands out in plastic housing assemblies, elastomer seal connections, enclosures made of engineering plastics, pipes and fittings, equipment covers, and various industrial assembly applications. Its main advantage is that it makes low-energy surfaces, which are difficult for standard adhesives to bond to, more suitable for adhesive bonding, while allowing low consumption and compatibility with short process times. Since the official safety classification includes warnings such as highly flammable liquid and vapor, skin irritation, and the risk of drowsiness or dizziness, it must be used in well-ventilated areas and in accordance with SDS rules. The technical data sheet also includes ISSA Code 75.509.19, although it should be noted that the main determining factors in product selection are the surface type and process validation.