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Overmolding Material Compatibility Chart: Which Soft Plastics Bond to Which Hard Plastics

PP-bonding TPE grades and TPV bond to polypropylene. TPU bonds to PC and ABS. ABS, PC and PC/ABS take TPE grades made for them (often called OM grades), and nylon takes a nylon-bonding TPE grade or a special TPU grade. PBT needs a PBT-rated grade. Where no grade bonds, a mechanical lock has to do the holding.

Bonding chart

This is general guidance from material makers' published data, plus Fudakin's production experience. Always confirm the exact grade with the resin supplier and in DFM. Hard plastics run down the left. Soft overmold materials run across the top.

  • Bonds Chemical adhesion with a grade sold for that pair.
  • Special grade Bonds only with a specific adhesion-modified grade. Confirm the grade.
  • Lock needed Design a mechanical interlock. Do not count on chemical adhesion.
  • No Do not rely on it.
  • Run at Fudakin, Shenzhen This kind of pair has run in Fudakin's Shenzhen production. It is not a grade rating.
Which soft overmold materials bond to which hard substrates
Hard substrateStandard SEBS TPEPP-bonding TPEPC/ABS-bonding (OM) TPENylon-bonding TPETPUTPV
PPSpecial grade1Run at Fudakin, ShenzhenBondsRun at Fudakin, ShenzhenNoNoNo2Bonds
ABSNo3NoBondsRun at Fudakin, ShenzhenNoBondsRun at Fudakin, ShenzhenLock needed4
PCNo3NoBondsRun at Fudakin, ShenzhenNoBondsRun at Fudakin, ShenzhenLock needed4
PC/ABSNo3NoBondsNoSpecial grade5Lock needed4
Nylon (PA6, PA66)No3NoNo6BondsRun at Fudakin, ShenzhenSpecial grade7Run at Fudakin, ShenzhenLock needed4
PBTNo3NoNo8No8Special grade5Lock needed4

The "Run at Fudakin, Shenzhen" badge marks these kinds of pairs: TPE (including TPR) on PP, TPE on PC and ABS, TPU on PC and ABS, and TPE or TPU on nylon. Fudakin does not publish bond test data, and this chart shows none.

Footnotes

  1. Sources disagree on standard SEBS on PP. Teknor Apex says styrenic TPEs and TPVs generally adhere to polyolefins. Fictiv says PP needs a specialized TPE. We show the more cautious code. Ask the supplier for a grade rated for your PP.
  2. Fictiv rates TPU on PP as limited. Komaspec rates it poor and says to use interlocks. If you need TPU on PP, treat it as a mechanical-lock design and confirm with the supplier.
  3. Teknor Apex says styrenic TPEs show poor adhesion to engineering plastics without chemical modification. A mechanical lock can still hold a standard grade in place, but do not count on a chemical bond. Use a grade from the matching column.
  4. Komaspec lists TPV as mechanical bond only on these substrates. Teknor Apex says TPV shows poor adhesion to engineering plastics without modification.
  5. Only some of the sources cover this pair. Komaspec rates TPU excellent on PC/ABS and good on PBT; Fictiv does not list either. Grade choice matters, so we show the cautious code.
  6. Avient names Versaflex OM grades for nylon 6 and 6/6, but as a separate nylon-specific grade. That is why nylon has its own column here. A PC/ABS grade should not be assumed to bond to nylon.
  7. Fictiv rates TPU on nylon as moderate and Komaspec as good. Moisture in the nylon changes the result. Dry the nylon to the supplier's level.
  8. Teknor Apex and Komaspec both describe PBT-bonding TPE grades, but they are a separate family from the columns above. None of our columns is a PBT grade, so we show No here. Ask the supplier for a PBT-rated grade.

Design rules that make bonds hold

  • Add a mechanical lock where the bond matters. Through-holes, undercuts and lips keep the soft layer on when chemical adhesion is uncertain. Fudakin uses locks on some parts, depending on the part.
  • Dry hygroscopic resins. PC, nylon, PBT and TPU take on moisture. Moisture at the interface hurts adhesion, and Fictiv calls drying nylon to the supplier's level often critical. Follow the resin supplier's drying sheet.
  • Keep the substrate clean and warm. Teknor Apex says moisture or mold release on the surface interferes with the bond. Fictiv notes that substrate preheat affects surface softening on PC. Higher melt temperature also raises bond strength, per Teknor Apex.
  • Keep the soft layer thick enough. Avient says wall thickness of 0.060 to 0.120 in (1.5 to 3 mm) gives good bonding in most overmolding applications. Teknor Apex warns that a layer that is too thin can delaminate. Keep transitions gradual, and use a 0.020 in minimum radius in sharp corners, per Avient.
  • Design the shut-off. To stop flash, Avient suggests a 0.003 to 0.005 in (0.076 to 0.127 mm) interference at the shut-off on plastic substrates, and an accent groove 0.015 to 0.030 in deep and 0.030 to 0.040 in wide to help the shut-off seal.
  • Check shrink and bond in DFM. Fudakin reviews both on every project before tooling starts. Bonds are checked by visual inspection and full-time QC.

Fudakin runs overmolding and dedicated two-shot (2K) presses in Shenzhen. We usually recommend two-shot over overmolding at around 10,000 parts a year and up. Seeovermolding vs two-shot vs insert moldingand why multi-material parts fail.

Sources

Every general cell and design number above comes from these published pages. Where they disagree or say nothing, the chart uses the more cautious code.

Tiger Li, Head of Operations, Fudakin. Last updated September 30, 2026.

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Send us the drawing and the materials. We will check the pairing in DFM and give you a straight answer.

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