Common Materials Used in Extrusion Blow Molding
What materials are commonly used in blow molding?
Common extrusion blow molding materials include HDPE, LDPE, and PP for daily-use containers and recyclable packaging; PETG and EVOH for transparent or barrier applications; TPE and ABS for automotive and industrial parts; and EPET for newer transparent PET-compatible applications. PC and PVC were used more often in the past but are less commonly recommended for many container applications today.
How are HDPE, LDPE, and PP used in everyday products?
HDPE is widely used for jerrycans, food containers, chemical containers, cleaning bottles, garden products, automotive accessories, and toys. It is tough, recyclable, and commonly processed on EBM machines.
LDPE is softer and often used for squeezable bottles, sports bottles, and hydration bags.
PP has higher heat resistance than PE and is used for products that require sterilization or hot filling, such as some milk or soy milk containers. PP usually requires hot cutting in extrusion blow molding.
LDPE is softer and often used for squeezable bottles, sports bottles, and hydration bags.
PP has higher heat resistance than PE and is used for products that require sterilization or hot filling, such as some milk or soy milk containers. PP usually requires hot cutting in extrusion blow molding.
What are PETG and EVOH used for?
PETG is an amorphous copolyester with high clarity and good impact resistance. It can be used for thick-bottom cosmetic bottles, skin-care packaging, and seasoning containers, but it is not suitable for every alcohol-containing product and should not be mixed with PET recycling streams.
EVOH provides strong oxygen barrier performance and is often used in food or medical containers to slow oxidation and extend shelf life. Because it is more expensive and difficult to recycle alone, it is commonly used in multi-layer EBM structures.
EVOH provides strong oxygen barrier performance and is often used in food or medical containers to slow oxidation and extend shelf life. Because it is more expensive and difficult to recycle alone, it is commonly used in multi-layer EBM structures.
Why are TPE and ABS used in automotive applications?
TPE is flexible, durable, and weather-resistant. It can be used for automotive dust covers and similar parts, often with lower processing temperature than traditional rubber and without sulfur curing.
ABS provides strength, toughness, and good surface finishing options such as painting, printing, or plating. It is used for selected automotive exterior or accessory parts.
ABS provides strength, toughness, and good surface finishing options such as painting, printing, or plating. It is used for selected automotive exterior or accessory parts.
Why are PC and PVC less commonly recommended today?
PC was once used for water bottles and baby bottles because of its clarity and heat resistance, but BPA-related concerns and regulations reduced its use in many consumer container applications.
PVC is clear, tough, and chemically resistant, but it often requires additives or plasticizers and can release hazardous substances when burned. It is restricted for many food-contact uses in various markets, though it still appears in some medical and industrial applications.
PVC is clear, tough, and chemically resistant, but it often requires additives or plasticizers and can release hazardous substances when burned. It is restricted for many food-contact uses in various markets, though it still appears in some medical and industrial applications.
What is EPET and why is it important?
EPET, or extrudable PET for blow molding, is transparent, non-toxic, and can be recycled with PET. Traditional PET is difficult to process by extrusion blow molding because of melt strength and bottom-line issues, but newer EBM materials and machine designs make transparent handled bottles possible. Jonh Huah has accumulated practical EPET EBM experience and can evaluate whether the material fits the target product.