The blow-molding industry utilizes technology and auxiliary equipment to enhance efficiency and profitability, promoting sustainability and the circular economy to minimize material and energy consumption.
FREMONT, CA: Blow molding is a crucial segment of the plastics industry for manufacturing rigid packaging and containers. It uses injection blow molding for PET bottles and extrusion blow molding for HDPE containers. EBM is used for large consumer and industrial products. Handling large volumes of material poses significant problems, as it requires moving pellets and conveying resin to in-plant surge bins, blow-molding machines, and auxiliary equipment.
Trends in Blow Molding
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The blow-molding sector focuses on reducing virgin plastics in packaging and increasing the use of recycled material. The first trend involves reducing scrap in packaging, leading to thinner wall sections and increased recycled material use. The second trend aims to improve manufacturing efficiency and reduce energy consumption. Extrusion blow molding produces scrap as a by-product, which can be conveyed to granulators or granulators. Automated systems are preferred due to labor shortages and plant efficiency. Regrind can be vacuum conveyed or transferred to a gravimetric blender for maximum control and production advantages. PET injection-blow-molding operations have fewer scrap issues than extrusion blow molders, and handling in-process PET regrind requires the same auxiliary equipment as extrusion blow molding.
Environmental consciousness and government mandates drive the increasing use of post-consumer-recycled resin (PCR) in packaging. Brand owners are specifying a percentage of PCR in their bottles and other blown containers, with some states requiring consumer bottles to contain a minimum amount of PCR. PCR pellets are blended with virgin material before being fed to the processing machine. Multilayer structures are common in HDPE blow molding applications, ensuring regrind or PCR is isolated from the packaged product by layers of virgin material.
Thin-walling is another approach to reduce virgin plastics used in packaging. PET blow molders can achieve thin sections by reducing the thickness of bottle walls without affecting package integrity. A desiccant dryer with complete control over drying parameters is essential for proper drying. A condensing filtration system called a demister can remove volatile compounds from the air, returning them from the hopper to the dryer, increasing confidence in quality production and maintaining well-maintained drying systems.
Reducing energy consumption is also an important trend driving auxiliary equipment decisions. Utilities, especially electrical power, are the second highest cost in most blow-molding applications, and drying is the major contributor. Sizing the drying system and using gas instead of electrical energy can help minimize energy consumption.
Reducing the use of virgin materials and reducing energy consumption are key strategies for packaging manufacturers. By incorporating PCR into packaging, utilizing post-consumer-recycled resin, and minimizing energy consumption, manufacturers can contribute to increased sustainability in the packaging industry.
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