The main plastic options - an overview
The ‘workhorse’ of the plastics industry, polypropylene is one of the high-volume “commodity” thermoplastics. It has low density, is fairly rigid, has a high heat distortion temperature of 150° to 200°F (making it suitable for “hot-fill” packaging applications), and excellent chemical resistance and electrical properties. In addition to these properties, PP is the best material for 'folding hinge' applications in plastic.
COPP – Co-polymer Polypropylene
This is a specially modified highly transparent polypropylene random copolymer with medium melt flow, intended for injection moulding and injection stretch blow moulding.
PE – Polyethylene
A thermoplastic material composed of polymers of ethylene. Polyethylene is the most widely produced polymer.
HDPE – High Density Polyethylene
Its comparatively high density gives HDPE high stiffness, high temperature resistance and very good water vapour barrier properties.
LDPE – Low Density Polyethylene
With its low density, LDPE is preferred mainly for its heat seal ability and bulk in packaging. It is also commonly used for reducer plugs in packaging.
LLDPE – Linear Low Density Polyethylene
Typically used for tubes, LLDPE is a copolymer material that is slightly stiffer and more stable than LDPE. It is also less prone to warpage and distortion on thin section mouldings.
PET – Polyethylene Terephthalate
PET plastics are generally clear in appearance and are available in a range of colours. Although lightweight, PET is tough and a good defence to gases and liquids. It is also highly resistant to dilute acids, oils and alcohols.
PETG – Glycol-modified Polyethylene Terephthalate
This is a durable material with an excellent gloss, clarity and sparkle that makes for very clear bottles. PETG can be processed via conventional extrusion blow-moulding methods, generally on machines designed to process PVC. It is popularly used for shampoos, soaps, and detergents. PETG has good impact strength and gas barrier qualities. The chemical resistance of PETG is fair, but compatibility testing is recommended, especially with products that contain alcohol.
PCTG – Poly-Cyclohexylenedimethylene Terephthalate Glycol
This co polyester material is similar to PETG and can be processed in the same manner. It has better chemical resistance and is generally easier to process than PETG. It can also create larger capacity and heavier weight containers through extrusion blowmoulding processes than with PETG.
PVC – Polyvinyl Chloride
A thermoplastic material composed of polymers of vinyl chloride, PVC is a colourless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalis. It is used in plasticized form for the production of containers such as liquid hand soaps, shampoos and bubble baths.
BDS – Butadiene-Styrene Block Copolymer
Has the clarity of SAN, but with the addition of an impact modifier. This allows moulding to flex without fractures
SAN – Styrene-Acrylonitrile Resins
The SAN copolymer generally contains 70 to 80% styrene and 20 to 30% acrylonitrile. This combination provides higher strength, rigidity, and chemical resistance than polystyrene, but it is not quite as clear as crystal polystyrene and its appearance tends to yellow more quickly.
PCR – Post Consumer Regrind
With the increased awareness of protecting the environment and consumer awareness for the need to recycle, M&H are able to offer post consumer regrind, which is re-used, broken down plastic bottles and containers. PCR can be offered between 25-100%. PCR can be offered in PET, HDPE and PP and can be used for injection, blowmoulding and extrusion processing requirements.
| Property | HDPE | LDPE | Poly-propylene | PVC | Poly-styrene | Barex | PET | PETG |
| Rigidity | M | Low | M to H | M to H | H | H | M to H | M to H |
| Impact | G | G | F | F | P | F | F | F to G |
| Moisture Barrier | G | G | G | F | U | P | F | F |
| Gas Barrier | P | P | F | G | P | E | G | G |
| Stress Crack Resistance | F | G | E | E | F | G | E | E |
| Clarity | HT | HT | VG | C | E | C | C | C |
| Cold Resistance | VG | VG | P to F | F | P | F | G | G |
| Heat Distortion Temp ºF | 171 | 111 | 205 | 170 | 207 | 165 | 176 | 158 |
| Chemical Resistance | HDPE | LDPE | Poly-propylene | PVC | Poly-styrene | Barex | PET | PETG |
| Solvents | U | U | F to U | U | U | F to G | P to U | P to U |
| Oil | F | P | F to G | G | P to F | G | G | G |
| Alcohol | E | E | E | G | P to F | G | G | G |
| Essential Oil Flavour | P | P | P to F | G | P | VG | G | G |
| Acid | E | E | G to E | G | P to U | F to G | P to F | P to F |
| Alkali | E | E | E | G | P to U | P to F | F to U | F to U |
M = Moderate H = High C = Clear HT = Hazy Transparent
Please note: These are a guide and we recommend you carry out your own tests to approve material compatibility.