Automotive trim adhesive usually takes 12-24 hours to fully cure (the specific time depends on the product technical parameters). Assembly, painting or transportation during curing may cause bonding failure, seriously affecting NVH performance and appearance quality. Mercedes-Benz and other OEMs clearly require that the ambient temperature must be maintained in the range of 15-30℃ during curing.
Different substrates such as ABS/PP/metal commonly used in car bodies need to be surface treated in advance. Taking the BMW paint shop as an example, polypropylene parts must be plasma treated or use a special primer (such as 3M™ Primer 94), otherwise it will cause the bonding strength to drop by more than 60%. This is an important control point in the IATF16949 audit.
Products such as two-component epoxy adhesives usually have only 30-90 minutes of operating time after mixing (such as Henkel Terokal® series). Toyota's production system requires the use of automatic glue coating equipment and the setting of time alarm devices. Unused automotive adhesive for trim must be scrapped, otherwise it will cause major defects such as poor weld sealing.
Suppliers such as BASF require that most structural adhesives automotive be stored in a constant temperature warehouse of 5-25℃. A US automaker once had a PUR hot melt adhesive worth $800,000 crystallized and scrapped due to a heating failure in the warehouse in winter. The VDA6.3 standard clearly stipulates that warehouses must be equipped with real-time temperature and humidity monitoring systems and inspected daily.
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