Most people think plastic is just plastic. But when it comes to running the injection moulding process, we know that not all materials are made equal.
As part of our service, we will advise you on which material will work best for your parts. Here are the materials we use, plus the positives and negatives associated with each:
- ABS
- Acetal
- ASA
- EVA
- PVC
- Polyamide
- Polypropylene
- Polystyrene
- Polythene
- TPR
Looking for rubber moulded parts?
We used traditional rubber moulding methods until 2003, but we no longer use natural rubber in any of our products. Why? Because we believe that synthetic rubber alternatives can do a better job than natural rubber – and they can save you money, too. Take a look at TPR and flexible PVC for good replacements for natural rubber.
ABS
Material type: Engineering grade
ABS is a thermoplastic polymer with a shiny, impervious surface, and is stronger than pure polystyrene.
✅ Toughness
✅ Rigidity
✅ Surface appearance
❌ Dissolved by many aromatic and chlorinated hydrocarbons
❌ Dissolved by esters and ketones
Acetal
Also known as: POM
Material type: Engineering grade
Acetal is a high-strength thermoplastic used most commonly in the automotive and consumer electronics industries.
✅ Fatigue endurance
✅ Stiffness
✅ Creep resistance
✅ Water resistance
❌ Not resistant to acids or bases
ASA
Also known as: Acrylonitrile Styrene Acrylate
Material type: Engineering grade
ASA was developed as an alternative to ABS, and has better weather resistance and good mechanical properties.
✅ Toughness
✅ Rigidity
✅ Very good weathering resistance
✅ Low-temperature characteristics
✅ UV resistance
❌ Attacked by concentrated acids
❌ Attacked by aromatic and chlorinated hydrocarbons
❌ Attacked by esters, ethers and ketones
❌ Toxic smoke generation when burned
EVA
Also known as: Ethylene-vinyl Acetate, PEVA
Material type: Engineering grade, flexible
EVA is similar to low-density polyethylene but has increased gloss, softness and flexibility. It has a rubber-like feel.
✅ Flexible
✅ Transparent
✅ Good low-temperature flexibility (-70˚C)
✅ Good chemical resistance
✅ High friction coefficient
❌ Poor tensile strength
❌ Low resistance to heat deformation
❌ Poor chemical resistance and barrier properties
PVC
Also known as: Polyvinyl chloride
Material type: Basic grade, flexible
Flexible PVC is a popular synthetic plastic polymer with many applications. It’s a good substitute for rubber.
✅ Excellent flexibility
✅ Electrical insulation properties
✅ Reasonably good weathering characteristics
❌ Sensitive to UV and oxidative degradation
❌ Limited thermal capability
❌ Thermal decomposition evolves HCI
Polyamide
Also known as: PA 6, PA 66, Nylon
Material type: Engineering grade
Polyamides such as Nylon 6 are tough and have good strength and elasticity. Nylon 66 is good for heat stability and chemical resistance.
✅ Toughness
✅ Rigidity
✅ Abrasion
✅ Hydrocarbon resistance
❌ High moisture pick-up with related dimensional instability
❌ Attacked by oxidizing agents
❌ Attacked by strong acids and bases
Polypropylene
Also known as: PP-Copolymer, PP-Homopolymer
Material type: Basic grade
Polypropylene is thermoplastic polymer with many applications. It’s rugged and has good resistance to solvents, acids and bases. [More]
✅ Excellent electrical insulation
✅ Chemical resistance
✅ Low water absorption
❌ Degraded by UV
❌ Attacked by chlorinated solvents and aromatics
❌ Difficult to bond
❌ Poor low-temperature impact strength
Polystyrene
Material type: Basic grade
Polystyrene is a synthetic aromatic polymer that has a solid, glassy state at room temperature but flows when heated above 100˚C.
✅ Rigidity
✅ Excellent electrical insulation
✅ Low moisture absorption
❌ Poor solvent resistance
❌ Attacked by many chemicals
❌ Subject to stress and environmental cracking
❌ Poor thermal stability
Polythene
Also known as: LDPE, LLDPE, MDPE, HDPE, Polyethylene
Material type: Basic grade
Polythene is the most common plastic and can be almost transparent (LDPE) or opaque (HDPE).
✅ Low relative cost
✅ Excellent electrical insulation
✅ Excellent chemical resistance
✅ Toughness (with slight flexibility)
❌ High thermal expansion
❌ Poor weathering resistance
❌ Subject to stress cracking
❌ Difficult to bond
❌ Low strength/stiffness
TPR
Also known as: TPE, TPU, TPV
Material type: Engineering grade, flexible
Thermoplastic rubbers (TPRs) are flame-retardant elastomers that we use as a replacement for natural rubber.
✅ Flexibility
✅ Excellent weather resistance
✅ Shock absorption
✅ Outstanding ozone resistance
❌ Relatively high cost
❌ More temperature sensitive than competitive elastomers
❌ Durability and toughness lower than competitive elastomers
Get in touch
Remember that we’re here to help. If you don’t know which material would be best for your parts, just get in touch and ask us for advice.
