Different Kinds of Plastics Used in Blow Molding

Stretch Blow Molding

In blow moulding, a plastic resin heats up until it becomes a liquid and flows into a mould cavity. The air pressure inside the mould cavity causes the liquid plastic to expand into the shape of the cavity. When the plastic cools and solidifies, it comes out of the mould. Blow moulded parts have a variety of applications, including automotive components, medical devices, and food containers.

Plastic blow molding machines are compatible with different types of plastic. Each type has its benefits and uses. Below are some of the most common plastics used in blow moulding and their properties.

High-Density Polyethylene (HDPE)

When blowing moulding, high-density polyethylene (HDPE) is king. It finds application in a wide variety of items. These include shampoo and motor oil containers, coolers, playsets, gas tanks, industrial drums, and storage containers. It is chemically inert, transparent, and easy to colour, making it ideal for use in moulding. This type of plastic uses Recycling Code 2.

Polypropylene (PP)

PP is the most widely used injection moulding resin and the second most common plastic in the world. In many ways, PP is analogous to HDPE, but with the added benefit of being slightly stiffer and less dense. PP is ideal for high-temperature applications, like dishwasher tubes and medical parts that need sterilization. It can be coloured and tinted readily, is translucent, and works well in moulds. Recycling Code 5 is used for this material.

Polyvinyl Chloride (PVC)

PVC is the third most widely used plastic in the world. Translucent PVC comes in rigid and soft resin forms, with the latter being the blow molding material of choice. Bellows, traffic cones, and other forms of flexible medical equipment, as well as other similar uses, are common. To avoid corrosion caused by HCl, we recommend using special processing equipment. PVC is assigned Recycling Code 3.

Low-Density Polyethylene (LDPE)

As a softer plastic, LDPE is ideal for items that need to be flexible yet also resistant to stress cracks. Squeeze bottles, traffic delineators, and boat bumpers are just a few of the many uses for this versatile plastic. The most common application is in the production of plastic grocery bags. It is translucent and easily coloured, is chemically inert, and is a favourite of moulders. This type of plastic uses Recycling Code 4.

Polyethylene Terephthalate (PET)

PET is a polyester used to make transparent containers using PET blow machines. The soft drink and water bottle industries account for most PET blow molding sales. Its recycling code is 1, which is very easy to recycle.

Thermoplastic Elastomers (TPE)

Moulded products can now come from TPEs instead of natural rubber. A colorable opaque substance (typically black). TPEs are excellent materials for bellows, grip surfaces, air intake ducts, and automobile suspension covers. After drying, it is malleable, and you can reprocess it without losing quality. However, with Recycling Code 7, recycling rates are restricted.

Get Blow Molding Equipment From a Trusted Source

Whatever plastic you use for blow moulding, make sure your plastic blow molding machines come from a trusted provider. When you work with Pet All Manufacturing Inc., you can be sure that you’re getting quality equipment and services. Contact us today to learn more about PET blow molding.

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