Processing Temperature, specific gravity and shrinkage rate of Common Plastic materials
Material shrinkage is a reduction in the volume of a material occurs when plasticizing plate cooling after moulding, it is a reduction of the dimensions of cooling plasticizing part, compared with its mould dimensions.
Material shrinkage is the contraction of a plasticizing plate as it cools after mould. It always occurs after ejection, as the part continues to cool. After that, the plate may continue to shrink very slightly for several hours or even days until the temperature and moisture content stabilize.
All polymers have different shrinkage rates depending on many factors. These include material category, moulding condition, mould structures, plate shape, plate interior structure, complexity, inserts etc.
Our chart below shows typical shrinkage ratios for the list of common materials:
Abbreviation | Full title | Specific gravity | Shrinkage rate | Temperature of processing | Temperature of mould |
LDPE | Low density polyethylene | 0.92 | 3 | 220~260 | 20~40 |
HDPE | High density polyethylene | 0.96 | 3 | 190~280 | 30~70 |
PP | Polypropylene | 0.91 | 2 | 210~280 | 20~50 |
PVC | Polyvinyl chloride | 1.38~1.41 | 1.5 | 170~190 | 20~40 |
ABS | Polyacrylonitrile Polybutadiene Polystyrene | 1.05 | 0.6 | 210~260 | 50~80 |
AS | Polyacrylonitrile Polystyrene | 1.07 | 0.6 | 220~270 | 40~80 |
BS | Polybutadiene Polystyrene | 1.01 | 0.5 | 190~230 | 30~50 |
GPPS | General purpose Polystyrene | 1.16 | 0.3~0.6 | 200~250 | 40~60 |
HIPS | High impact Polystyrene | 1.08 | 0.5 | 210~270 | 20~50 |
EVA | ethylene-vinyl acetate copolymer | 0.95 | 2 | 140~200 | 20~40 |
PMMA | polymethyl methacrylate | 1.18 | 0.6 | 220~240 | 60~80 |
PA6 | Polyamide 6 | 1.13 | 0.7-1 | 250~270 | 40~60 |
PA66 | Polyamide 66 | 1.13 | 1.3 | 280~300 | 40~60 |
PA66+30%GF | Polyamide 66 +30% glass fibre | 1.39 | 0.3 | 240~270 | 80~90 |
POM | polyformaldehyde | 1.42 | 2.1 | 205~225 | 80~100 |
PC | Polycarbonate | 1.2 | 0.5 | 271~293 | 71~93 |
PET | Polyethylene glycol terephthalate | 1.33 | 0.4 | 277~293 | 15~30 |
PET+30%GF | Polyethylene glycol terephthalate +30% glass fibre | 1.67 | 0.2 | 265~305 | 95~150 |
PETG | Polyethylene terephthalate glycol | 1.27 | 0.2~0.5 | 250~270 | 15~40 |
PCTG | Poly Cyclohexylene Terephthalate Glycol | 1.23 | 0.2~0.5 | 275~295 | 15~40 |
PBT | polybutylene terephthalate | 1.4 | 1.5~2.2 | 225~245 | 40~80 |
PBT+30%GF | polybutylene terephthalate +30% glass fibre | 1.61 | 0.4~0.9 | 225~250 | 40~100 |
PCT+30%GF | Polycarbonateterephthalate +30% glass fibre | 1.45 | 0.1~0.4 | 295~370 | 105~135 |
CA | cellulose acetate fibre | 1.26 | 0.5 | 160~230 | 40~60 |
CAP | cellulose propionate | 1.2 | 0.5 | 215~240 | 40~75 |
CAB | cellulose butyrate | 1.19 | 0.5 | 230~250 | 40~85 |
Heat-resisting PP | Heat-resisting polypropylene | 1.12 | 0.9~1.1 | 180~220 | 60~80 |
Fire retardant PP | Fire retardant polypropylene | 0.95 | 1.4 | 180~220 | 30~50 |
PPS+40%GF | Polyphenylene sulfide +40% glass fibre | 1.67 | 0.25 | 300~340 | 120~150 |
PPO |
| 1.07 | 0.5~0.8 | 270~310 | 70~93 |
PSU |
| 1.24 | 0.5 | 330~360 | 120~160 |
PES |
| 1.37 | 0.68 | 340~380 | 120~160 |
LCP | Liquid Crystal Polymer | 1.7 | 0.02 | 385~400 | 35~200 |
SBS | Styrene-butadiene-styrene block copolymer | 0.96~1.1 | 1.5 | 145~160 | 25~30 |
SEBS | Styrene Ethylene Butylene Styrene | 0.87~0.91 | 1.6 | 180~220 | 35~65 |
TPU | Thermoplastic polyurethanes | 1.24 | 1.2 | 190~220 | 24~49 |
TPV | Thermoplastic Vulcanizate | 0.97 | 1.5~2.5 | 180~190 | 10~80 |
TPEE | Thermoplastic elastomers | 1.2 | 1.4 | 220~250 | 45 |
This information should only be used as a quick reference.
Users should always refer to the processing data sheets provided by the material supplier. Differential shrinkages are not considered. Your use of this data is entirely at your own risk and BOYU accepts no liability of any kind.