Before diving into the process of plastic bottle manufacturing, let us quickly glance over the most commonly used plastic resins used in rigid plastic packaging: Typically, most plastic bottles have a recycling symbol in the bottom, which can be used by the consumer and recycling centre to identify and sort different plastic types for recycling, and re-use.
High Density Polyethylene (HDPE)
HDPE is the most widely used type of plastic. It’s used to make many types of bottles and containers. HDPE has good chemical resistance and stifness, and is versatile. It is well suited to packaging products such as milk, many household chemicals such as detergents and bleach.
Polyethylene Terephthalate (PET, PETE)
PET is clear, tough, and has good gas and moisture barrier properties. This resin is commonly used in beverage bottles.
Polypropylene (PP)
PP has good chemical resistance, is strong, and has a high melting point making it good for hot-fill liquids.
Blow moulding can is the plastic bottle manufacturing process or technique where the air is blown in a heated plastic until it fills a mould and forms the desired shape to produce hollow parts. Or in more basic terms, we can understand blow moulding to be the process where,plastic is melted down, clamped into a mould, and then air is blown into it to produce the desired hollow object/shape.
The different types of blow mouldingto produce rigid plastic packaging are: Extrusion blow moulding, Injection blow moulding, Stretch blow moulding and Reheat and blow moulding.
(1 ) Extrusion Blow Moulding:
In thisplastic bottle manufacturing process of extrusion blow moulding, a hot tube of plastic material (parison) is dropped from an extruder and captured in a water-cooled mould. Once the mould is closed, the air is injected through the top of the container. When the hot plastic blows up and the mould material freezes, allowing it to be able to maintain its shape.
Applications: Widely used for manufacturing opague plastic bottles made out of HDPE, PP & LDPE. For plastic containers with handles, this is the most common process. Relative to other processes, the cost of blow mould is economical, and it is popular for custom packaging solutions. Some end use bottles are automotive lubricants, motor oil, tablet, cleaners, chemicals bottles.
Sustainability: It is also possible to incorporate recycled plastics or Post Consumer Recycled (PCR) plastics by using multi-layer technology. When a consumer puts an used HDPE Bottle into a recycling bin, it makes its way to a recycling centre, where the bottle is washed, cleaned and converted back into recycled plastic granules. These recycled granules are procured by a bottle manufacturing company, which may chose to make a new bottle with 25% or even 100% PCR. In today’s day and age, consumers are becoming more environmentally conscious, and many brands are adapting their plastic packaging and supply chains to embrace and promote recycled plastics.
2) Injection blow moulding:
In this method, hot plastic material is injected into the part of the mould that forms the neck. The injected material is then taken to the next station of the machine where it is blown up into the finished container like in the extrusion blow moulding process.
Applications: Healthcare & Pharmaceuticals bottles and HDPE plastic bottles.
(3) Stretch blow moulding:
This method is mostly used for producing transparent bottles commonly used for water, juice, and other similar products. The injection stretch blow moulding machinery moulds a preform, which is then transferred to another station where it is blown and then ejected from the machine.
(4) Reheat and blow moulding:
This is a type of stretch blow process in which a preform is injection moulded by an outside vendor. Many companies produce these stock pre-forms on a commercial basis. Factories buy the preforms and put them into a machine that reheats them so they can be blown.
Applications: End users such as beverages companies or liquour companies, purchase ready preforms, blow them and fill them with their product on an intergrated line. The bottles are typically transparent or amber in colour and made out of PET resin (Polyethylene terephthalate). For high volume, it is possible to get economies of scale using this process and reduce plastic containers price using this process.
With advancements in technology, plastic bottle manufacturing has become state of the art, and it is possible to produce a functional plastic container with a barrier or pilfer proof aspect that may serve to not only protect the product filled inside but also to prevent pilferage or theft.
Based on the requirement of customers, plastic containers manufacturers decide what plastic resin and plastic resin is best for the application. Accordingly, they select and present the correct plastic containers for packaging.
Take a look at the high quality HDPE bottles available from RegentPlast to find your product or contact us for your custom packaging solution.
