Five Essential Raw Materials for Extrusion Blow Molding Explained

1. HDPE, LDPE, PP
Material for daily necessities and suitable for recycle.

2. PETG, EVOH
Material usually not applied for daily necessities and not easy for recycle.

3. TPE, ABS
Material usually applied for auto industry.

4. PC, PVC
Used commonly in the past time, but no longer recommended presently.

5. EPET
New raw material expected to become mainstream in the future.

HDPE (High-density polyethylene): can withstand temperatures from 90~110(°C) with color of translucent or milky. Crystallinity high, flexible and durable, no toxin and recyclable, is the commonest material for Extrusion Blow Molding machine. Widely used on jerry can, food container, chemical container, cleaning container, garden supplies, car accessories, and toys, etc.

LDPE (Low-density polyethylene): can withstand temperatures 70~90(°C), translucent or transparent, lower density than HDPE, soft with good flexibility. No toxin occurred and recyclable. Usually applied on sport bottle, mountaineering water bag, etc.

PP (Polypropylene): can withstand temperatures 100~140(°C) with color of translucent or milky. Hot cutter used when extrusion blow molding. No toxin occurred and recyclable. Looks similar to PE but more transparent, and harder after cooling. Higher heat resistant than PE, usually applied on containers for milk or soy milk that needs to be sterilized or filled with high temperature.

PETG (Poly ethylene terephthalateco-1, 4-cylclohexylene): Amorphous copolyester, product after forming is highly transparent and with excellent performance of impact resistance. Imitated thick bottom glass bottle can be produced by Extrusion Blow Molding machine and applied on containers for skin care, cosmetics, seasoning jar in kitchen; but unavailable for alcoholic content, and cannot be recycled mixed with PET.

EVOH (Ethylene vinyl alcohol): A special thermoplastic polymer / Ethylene vinyl alcohol copolymer. Transparent with well performance of oxygen cut off, can replace glass and metal containers to apply on food or medical containers to prevent oxidation and spoiled, and extend the life of contents. Higher price cost so usually applied on multiple layers Extrusion Blow Molding machine, not easy to recycle separately.

TPE (Thermoplastic elastomer): High elasticity of rubber, high strength. Environmental friendly and non-toxic, safe and soft, with characteristics of weather resistance, fatigue resistance and temperature resistance. Automobile dust cover can be produced with Extrusion Blow Molding machine, and compares to the procession of traditional rubber, it needs lower temperature, no need to add sulfur, higher rate of output, recyclable, and cut cost efficiently.

ABS (Acrylonitrile Butadiene Styrene): High strength, well toughness, easy to process thermoplastic polymer structure raw material. Suitable for spray paint, print, and plating, etc. Usually applied to the car spoiler production by Extrusion Blow Molding machine.

PC (Polycarbonate): can withstand temperatures 120~130(°C), high transparent. Used to be applied the water bottle and baby bottle, but since the environmental hormone bisphenol A was found from the liquid in the bottle and had bad effect on human body, it has been disabled by many countries.

PVC (Polyvinyl Chloride): can withstand temperatures 60~80(°C), transparent, tough, excellent corrosion and chemical resistance. Lower price cost, used to be applied the food containers and toys. However, additives or plasticizers are required for processing, and toxic dioxin will be released to increase the risks of cancer and affect the reproductive function when burning, lots of countries have disabled this material application, and it’s not common to be seen as food containers, but the medical equipment.

EPET (Extrusion Blow PET, Extrudable PET): can withstand temperatures 60~85(°C), transparent, non-toxic, can be recycled with PET. High melt index makes it difficult to fabricate by extrusion blow molding (there will be a line under the product bottom), so the only way is to produce a bottle parison by injection machine, and then blow the finished product by two-axis extension molding machine (there will be a dot under the product bottom). Limited by two-axis extension forming in the past, only simple round bottle without handle could be produced. However, some Extrusion Blow Molding industries and raw material manufacturers have broken through technologies to blow molding clear bottles integrating a true through-handle and that can carry the ‘PETE #1’ resin symbol for recycling with PET. Jonh Huah Plastic Machinery is the only manufacturer who can manufacture EPET Extrusion Blow Molding in 2022 in Taiwan.