PP (Polypropylene) is a non-polar plastic with low surface energy and difficult bonding properties. It has a smooth surface and tends to exude mold release agents and lubricants. Ordinary instant adhesives such as 502 and 401 deliver almost no bonding effect when used directly. Surface activation treatment is preferred to achieve reliable bonding. Adhesive selection shall be determined first according to specific working conditions.

Working Condition: Small Area & High-Speed Assembly on Production Lines

Application: PP to PP, PP to metal / small ABS parts; bonding area ＜25 cm²

Recommendation: SUITIT SG438 / SG480 toughened instant adhesive + SUITIT SG7452 primer

Working Condition: Large Area / Structural Load-Bearing / Dissimilar Material Bonding

Application: PP sheets, PP pipes, PP bonded to iron / aluminum, outdoor thermal cycling and vibration environments

Recommendation: Two-part polyurethane structural AB adhesive

Features: The cured adhesive layer features good toughness and can fill minor gaps. It offers resistance to water, oil and weathering. Fair bonding strength can be achieved without primer, while surface priming further improves adhesion strength. It supports structural load bearing and impact resistance, ideal for long-term industrial service conditions.