Manufacturing Plastic PET Bottles

empty 300ml round PET plastic milk bottle

“How are plastic bottles made”, Zhenghao will show you the manufaturing method, you will also get the answer from our custom service.

PET bottle is a kind of plastic material called polyethylene terephthalate, which also simply called PET. It is a polymer produced by the combination of terephthalic acid and ethylene glycol. PET plastics are light in quality, transparent and impact resistant to fragmentation, they can also prevent carbon dioxide gas and keep soda water gas.

1. Main Advantages of PET Bottles

38mm neck square juice pet bottle
  1. PET plastic bottles combine the texture of glass bottles but maintain the characteristics of plastic bottles, that mean plastic bottles can keep the appearance of glass bottles, but have the advantages of not fragile, safe, environmental protection, good transportation, than glass bottles.
  2. PET plastic bottle can be produced into different bottle type, different capacity products, rich variety of products, used in packaging such as cosmetics, medicine, health care, beverages, mineral water, reagents, etc.
  3. PET plastic bottles are transparent, airtight, pressure-resistant and easy to shape.
  4. Environmental protection and low cost. Glass due to material constraints, manufacturing and recycling will produce a certain amount of environmental pollution. With the development of science and technology, plastic bottles can be recycled and recycled to reduce environmental damage.
  5. Plastic bottles are safer to use. Glass bottles are fragile and are not 100% safe for children or the elderly. Also, because of the strong thermal conductivity of glass, glass bottles used to hold hot liquid when the skin injury, accidentally scalded. And plastic bottles, there is no such concern.
  6. PET plastic transparent bottle use temperature not more than 70℃, non-toxic, tasteless, good hygiene and safety, can be directly used in food packaging.
  7. PET bottle has high transparency, resistance to most solvents, can block ultraviolet rays, with good gloss.

2. manufacturing method

The manufacturing method of PET bottle is called injection-blowing molding method, that is forming a bottle perform by injection molding process, then forming PET plastic bottle after blow molding process. There are one-step and two-step process.

2-1. One-step process

Plasticize the PET particles, then inject into different models of bottle embryo, then adjust and blow into needed empty bottles.

one step bottle blowing machine
one step bottle blowing machine
one-step process
one-step process

2-2. Two-step process

At present, most of the blowing machine still use the two-step method to blow PET bottles, that is, making the environmentally friendly PET raw materials into a bottle embryo, and then to blow the bottle embryo into a empty bottle.

bottle embryo machine
bottle embryo machine

The blowing process of the bottle blowing machine is divided into two steps: heating and blowing.

1) Heating

The bottle embryo is irradiated by infrared high temperature lamp tube, so that the body of the bottle embryo is heated and softened. To maintain the shape of the bottle mouth, the bottle embryo mouth does not need to be heated, so a certain cooling device is needed to cool it.

2) Blowing

Place the preheated bottle embryo into the finished bottle mold, and inflate it inside by high pressure, then blow the bottle embryo into the needed bottle.

blow molding process
blow molding process

The automatic bottle blowing machine completes the two operation of the bottle blowing together through the operation of the manipulator, which avoids the process of putting the preheated bottle embryo into the mold manually in the middle, and greatly heats up the efficiency of production.

3. prospects for development

PET bottle has a strong application, widely used in daily necessities, daily chemical packaging and other fields. From mold processing to machinery and equipment have a strong picky, easy to get started, difficult to be fine.

Due to its advantages, many drinks that require high temperature sterilization to be filled, such as flavored water, juice, dairy products, sports drinks and so on, have also been packaged in PET bottles.

PET bottles have replaced PVC bottles, bags, aluminum cans, iron cans, glass bottle, and become the main packaging for drinking products.

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