Injection moulding of PET
Polyethylene Terephthalate (PET) is one of the most widely used thermoplastics, with global demand increasing year on year. This can be attributed to many factors such as:
- high clarity
- good mechanical properties
- great recyclability
- versatility, and
- low toxicity
all whilst remaining a low-cost material.
PET is consequently widely used for food packaging and has increased in popularity, particularly for its ability to replace glass packaging for a fraction of the weight leading to reduced CO2 emissions during the transportation of packaged goods. PET is a truly circular plastic and one of the best examples within the Circular Plastics Economy due to the ease of recyclability combined with continuous technological advancements in recycling infrastructure.
Alongside food packaging applications, PET finds its use in many other applications and is therefore processed in a variety of ways. Many converters injection mould PET to create parts such as PET bottle preforms that are eventually stretch blow moulded. However, the injection moulding process of PET is not without its challenges.
Why use our additive IncroMax 100?
The inherently high friction of PET leads to a whole host of problems such as poor de-moulding resulting in stuck articles, increased downtime and poor surface quality of the fully moulded part. Also, high temperatures and high pressures are required during processing leading to a higher energy consumption. Solutions to increase output rate, energy efficiency, and reduce surface friction are increasingly sought after.
IncroMax 100 is a unique additive, especially designed to bring energy, material, and cost savings to the PET injection moulding process. IncroMax 100 is added directly into the injection moulding process, preferably via a masterbatch or compound, and works within the polymer to give the following benefits:
- Reduction in energy usage during injection moulding
- Fewer rejects, and therefore less waste
- Improved slip performance
- Better aesthetics of the injection moulded part, by means of improved scratch resistance
- Excellent transparency
- Better packing density of injection moulded parts
- Easier stretching at lower temperatures & less stress whitening during stretch blow moulding or thermoforming
- EU and FDA Food contact approval
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Bring benefits to every stage of the injection moulding process of PET
Watch this short video and learn more about the use of IncroMax 100 and the benefit this additive brings to each stage of the PET injection moulding process.
Improving packaging density of injection moulded PET preforms
A case study
Manufacturing PET bottles usually involves a two-step process with the production of an injection moulded PET preform which is then stretched and blown inside a mould to produce a full-sized bottle. The PET preforms are often injection moulded and ejected directly into a crate which is then transported to the bottle blowing plant. To reduce transportation costs, it is advantageous to fit more parts into the crates.
A 50-litre drum was placed directly under the ejection shoot of an injection moulding machine and 550 PET preforms were ejected into the drum. The volume occupied by the preforms with no additives was 39 litres. When IncroMax 100 was added at 0.5% the volume dropped to 35 litres. This equates to a better than 10% improvement in packing density, leading to reduced packaging and transportation costs for the end customer.
Improve processing efficiency by up to 4.5% and reduce energy use per unit by up to 20%?
