Key facts
A practical injection molding materials list: 30+ resins from commodity PP and ABS to PEEK and LCP, with properties, typical uses and selection advice from Shiny Mold engineers.
Material choice drives cost, appearance and durability more than any other decision after the design itself. This is the practical map our engineers use to narrow 30+ resins down to the right one.
Commodity Resins
- PP: chemical resistance, living hinges, food-safe grades – the volume champion
- PE (HDPE/LDPE): tough, cheap, moisture-proof – containers and housewares
- ABS: strong, paintable, dimensionally stable – the default housing resin
- HIPS/PS: economical, easy to texture – internal parts and packaging
Engineering Resins
- PC: impact strength and transparency – lenses, shields, enclosures
- PC/ABS: best-of-both for automotive interior and electronics
- PA6/PA66 (GF-filled): strength and heat – brackets, gears, under-hood
- POM: low friction, high stiffness – gears, sliders, mechanisms
- PBT/TPE/TPU: electrical parts, soft grips, sealing
High-Performance Resins
PEEK, LCP and PSU for extreme heat, chemical and electrical performance – medical, aerospace and electronics applications where the material justifies its price.
Not Sure Which?
Send us your load, temperature, chemical and appearance requirements – our engineers return 2-3 material options with trade-offs in plain language, free with your DFM review.
Material properties that drive mold design
Two numbers matter more than any datasheet marketing line: shrinkage and abrasiveness. Shrinkage decides cavity dimensions – PP at 1.2-2.0 percent needs a different cavity offset than PC at 0.5-0.7 percent, and glass-filled grades shrink directionally, which is why mold flow analysis runs before steel is cut on glass-filled programs. Abrasiveness decides steel: glass-filled nylon eats P20 gate steel in tens of thousands of shots but runs fine in hardened H13.
The five resins we mold most
- ABS – housings, clips, painted parts; molds easily, cheap to run
- PC – impact and clarity; needs 120 C+ drying before molding
- PP – living hinges, containers; cheapest cycle in high volume
- PA66-GF30 – metal replacement; watch warpage and steel wear
- TPE/TPU – grips, seals; usually two-shot onto a rigid substrate
Material selection interacts with tooling cost more than buyers expect – the steel selection guide and cost breakdown explain both sides.
Handling matters as much as selection. Hygroscopic resins – PC, PA, PETG, TPU, COC – arrive sealed but absorb ambient moisture within hours once opened, and wet resin shows up as splay, bubbles and a 20-30 percent drop in impact strength. Our floor rules are simple: sealed storage, desiccant dryers with dew-point monitoring, drying times logged per lot, and opened bags used within the shift. Regrind, when approved, is dried with virgin material in controlled blends. None of this is glamorous; all of it is why parts look the same in January and July.