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 everyday products and containers; PETG and EVOH for selected clarity or barrier requirements; TPE and ABS for some automotive and industrial parts; and EPET for applications evaluated with extrudable PET. Suitability, food-contact status, and recyclability depend on the resin grade, product design, intended use, and local requirements. PC and PVC may still be used in specific applications; confirm suitability for the product and market.
How are HDPE, LDPE, and PP used in everyday products?
HDPE (high-density polyethylene) is often translucent or milky white and is used for jerrycans, food and chemical containers, cleaning bottles, garden products, automotive accessories, and toys. Its temperature performance depends on the resin grade, container design, length of use, and contents, so confirm it under actual conditions.
LDPE (low-density polyethylene) is generally softer and can be evaluated for squeeze bottles, some sports bottles, and hydration bags; its clarity and use conditions depend on the grade and design.
PP (polypropylene) generally has higher heat resistance than PE and may be considered for containers requiring hot filling or sterilization. Actual performance and food-contact or recycling suitability must be confirmed for the selected grade, product design, and market. PP often requires hot cutting in extrusion blow molding.
LDPE (low-density polyethylene) is generally softer and can be evaluated for squeeze bottles, some sports bottles, and hydration bags; its clarity and use conditions depend on the grade and design.
PP (polypropylene) generally has higher heat resistance than PE and may be considered for containers requiring hot filling or sterilization. Actual performance and food-contact or recycling suitability must be confirmed for the selected grade, product design, and market. PP often requires hot cutting in extrusion blow molding.
What are PETG and EVOH used for?
PETG (glycol-modified polyethylene terephthalate) is an amorphous copolyester that can provide high clarity and impact resistance. It may be evaluated for cosmetic, skin-care, and seasoning containers. Compatibility with contents and recycling routes depend on the grade, product design, and local system; do not assume suitability for every alcohol-containing product or PET recycling stream.
EVOH (ethylene-vinyl alcohol copolymer) provides oxygen-barrier properties and may be used as a layer in multi-layer containers. Barrier performance depends on the grade, layer thickness, structure, and use conditions. Multi-layer structures can be difficult to separate for recycling, so evaluate them against the product need and local recycling system.
EVOH (ethylene-vinyl alcohol copolymer) provides oxygen-barrier properties and may be used as a layer in multi-layer containers. Barrier performance depends on the grade, layer thickness, structure, and use conditions. Multi-layer structures can be difficult to separate for recycling, so evaluate them against the product need and local recycling system.
Why are TPE and ABS used in automotive applications?
TPE (thermoplastic elastomer) grades can provide elasticity and weather resistance, and some formulations may be evaluated for automotive dust covers and similar parts. Processing conditions, durability, and recycling options depend on the selected formulation.
ABS (acrylonitrile-butadiene-styrene copolymer) can provide strength and toughness, with painting, printing, or plating considered according to the grade and part requirements. The suitable forming process depends on part geometry and material conditions.
ABS (acrylonitrile-butadiene-styrene copolymer) can provide strength and toughness, with painting, printing, or plating considered according to the grade and part requirements. The suitable forming process depends on part geometry and material conditions.
What conditions should be confirmed when using PC and PVC in blow-molded containers?
PC (polycarbonate) is clear and can be used where heat resistance is required. Some PC formulations were used for water and baby bottles; consumer concerns about BPA and local rules mean suitability must be checked for the grade and target market.
PVC (polyvinyl chloride) can provide clarity, toughness, and chemical resistance depending on its formulation, which may include additives or plasticizers. Burning or improper disposal can release hazardous substances. Confirm food-contact or medical suitability against the specified formulation, product certification and requirements, and local rules.
PVC (polyvinyl chloride) can provide clarity, toughness, and chemical resistance depending on its formulation, which may include additives or plasticizers. Burning or improper disposal can release hazardous substances. Confirm food-contact or medical suitability against the specified formulation, product certification and requirements, and local rules.
What is EPET, and what should be evaluated for its use?
EPET, or PET developed for extrusion blow molding, must be evaluated for heat performance, clarity, and compatibility with PET recycling according to the specified grade, product structure, and local recycling rules. Processing conventional PET by extrusion blow molding requires suitable melt strength and a stable parison. Extrusion blow molded containers have a pinch-off seam at the base. PET containers can also be formed from an injection-molded preform by stretch blow molding. Jonh Huah has worked on EPET EBM equipment since 2022 and can evaluate a proposed product's shape, clarity, handle design, and recycling requirements.