Injection stretch blow moulding

Fig. 4.25 Extrusion stretch blow moulding Injection Stretch Blow Moulding...

Injection stretch blow moulding in which all the operations are performed on the same line. The preform is stretched with a stretch rod . Stretching improves the mechanical performances and allows the production of thinner walled bottles. 

Development of markets for PLA injection stretch blow moulding applications. 

The main markets for PLA are thermoformed trays and containers for food packaging and food service applications. Other developing areas include films and labels, injection stretch blow moulded bottles and jars, specialty cards and fibres. 

The main types of NatureWorks PLA that are available for packaging applications include general purpose film grades, extrusion coating, extrusion and thermoforming grades and injection stretch blow moulding. 

PLA is available in grades suitable for manufacture of injection stretch blow moulded bottles. It is claimed these offer comparable organoleptic properties to glass and PET making it suitable for a variety of short shelf-life food and beverage bottling applications. 

Injection stretch blow moulding (ISBM) is used for the production of high quality and high clarity containers. PET is the most widely used polymer for injection stretch blow moulding of botdes. During the last two years, there has been a growing interest from brand owners and retailers in the use of PLA for manufacture of stretch blow moulded botdes for short shelf-life products such as mineral water and milk. 

Injection stretch blow moulded bottles and jars for short shelf-life applications that use cold-filling techniques such as still water, fresh juices, dairy beverages and edible oil. 

As PLA prices move closer to those of PET there may be a tendency for brand owners to switch from PET in favour of biodegradable polymers such as PLA for injection stretch blow moulded bottles, not only on cost grounds, but also because renewable packaging materials have marketing advantages for the consumer. 

Alpha Packaging manufactures botdes and jars made from polyethylene terephthalate (PET) and high-density polyethylene (HDPE) for the pharmaceutical, nutritional and personal care markets. Technologies used include injection blow moulding, injection stretch blow moulding, and extrusion blow moulding. Alpha manufactures stock and custom containers in a variety of styles and colours. 

Fig. 20.4 The injection stretch blow moulding process (ISBM).

Although both processes can produce reasonably good quality large containers, injection stretch blow moulding is more widely used for pharmaceutical containers. The first stage of moulding is basically as injection blow moulding. In the second... 

A. Garcia-Rejan, K. Y. Nguyen, W. Michaeli, L. Morich, G. Schnidt, and R. Lusignea, Injection stretch blow moulding of PET/LCP blends for better product performance, SPE ANTEC, pp. 1029-1033, New York, NY, May (1999). 

Clarifying additives enable PP to compete for applications that were previously captive to PET or polycarbonate, both of which cost more. PP supplier Borealis and Milliken have developed a two-stage injection stretch blow moulding process, used for still water bottles and juice containers, that allows the rapid manufacture of clear PP bottles at up to 1500 bottles per hour from each mould cavity, using Milliken s clarifiers. 

Clarified PP preforms are available that enable PP bottles to be made at lower total production costs while still achieving excellent transparency, using standard injection stretch blow moulding machines. This has required specialised technology developed by companies like PPaM International, who designed their system for symmetrical bottles to contain noncarbonated water, juices and drinks. Comparable products could previously only have been made using PET. 

Figure 4.3 illustrates the various stages of injection-stretch blow moulding. The biaxial orientation also provides permeation to gas, liquid and odour due to an increased molecular alignment. This process produces bottles or containers which are scrap-free, and have close tolerance, i.e., a complete finish which does not required any secondary operations. 

Figure 4.3 Various stages of injection-stretch blow moulding...

In stretch blow moulding process, the preform is stretched in both hoop direction and the axial direction as it is blown into Ae mould. Air blow with stretch rod create the final product by stretching the preform to the mould cavity. Injection stretch blow moulding process has two different blowing stages which are pre-blow and final blow. Stretch rod comes to the end of the bottle cavity with preblow assistance. The time in between stretch rod touches the preform and reaches the end of the cavity is crucial in order to get desired stretch ratio. These two points are named point 0 and point 10. Final blow is applied for the rest of the blowing process right after preblow. 

Injection stretch blow moulded PET bottles offer glass like clarity, excellent gas barrier properties and good overall mechanical strength. However, PET bottles required for hot-fill (85 °C ) plications have encountCTed limitations due to its relatively low glass transition temperature. 

In this study, two virgin PET grade materials are blended with post consumer recycled PET. The heat-setting technique is used for the manufacturing of injection stretch blow moulded bottles for hot-fill plications. The process parameters (the preform temperature, the heatsetting timing and blow mould temperature) and the blend ratios for PET bottles are optimised based on thermal and mechanical characterisation. 

Biaxial orientation of PET containers by mechanical means - axially by a stretch rod, radially by high-pressine air- during injection stretch blow moulding process introduces strain-induced crystallinity. Strain-induced crystallisation has a direct influence on the level of crystallinity of the final product. Factors, which influence the crystallinity level and the morphology, include the ISBM mould temperature, blow pressure and time to stretch the preform. 

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