What are the processes for plastic packaging bottles?

Injection blow molding and injection stretch blow molding can usually be used as packaging for food, medicine, cosmetics and daily chemical products. They have distinct highlights but also have their limitations.

Difference 1. difference of production raw materials

Commonly used plastic raw materials for squeeze-blow plastic bottles are: HDPE LDPE PP PVC PETG.

Commonly used plastic raw materials for injection stretch-blow plastic bottles are: PET PP HDPE PMMA

Difference 2. Process difference:

Extrusion blow molding of plastic bottles without preforms

Injection stretch blow plastic bottles need to be injected first and then blow molded

Difference 3. Difference in production:

After extrusion blow molding, the bottles need to be mechanically or manually removed from the excess glue, and some also need to polish and trim the bottle mouth.

After the injection stretch-blow process bottles are released from the mold, they can be directly packed into boxes or processed for other processes without the need for secondary processing.

Difference 4. Difference in appearance of bottle bottom:

Extrusion-blow plastic bottles have a clamping mouth at the bottom of the bottle.​

Injection stretch-blow plastic bottles have no mold closing line at the bottom of the bottle.

Difference 5. Mold difference:

Extrusion blow molding of plastic bottles requires: two sets of bottle blowing molds. Of course, sometimes one set can also be made, depending on production needs.

Difference 6. Application market of selected materials:

1. Application of extrusion blown plastic bottle materials in the plastic bottle industry:

HDPE (low-pressure high-density polyethylene): general packaging bottles for daily chemicals, such as: shampoo bottles, shower gel bottles, laundry detergent bottles.

LDPE (high-pressure low-density polyethylene): eye drop bottles, e-liquid bottles, hose bottles, condiment bottles and other products that require extrusion.

PP (polypropylene): Food and pharmaceutical plastic bottles are mostly based on the one-step injection-stretch-blow method and the injection molding process.

PETG (polyethylene terephthalate): cosmetic packaging bottle.

2. Application of injection stretch blow molded plastic bottle materials in the plastic bottle industry:

PET (a type of polyester): beverage bottles, cosmetic bottles, water bottles, daily chemical bottles, health care product bottles, etc.

PP: food bottles, baby bottles, medical supplies bottles (Note: as food grade, it is mostly a one-step process).

HDPE: Medical supplies bottle (Note: Like PP, it is mostly produced by a one-step process).

PMMA (commonly known as acrylic): It is mostly used in cosmetic packaging bottles, and most of them are based on injection molding technology.

Injection blow molding and injection stretch blow molding can usually be used as packaging for food, medicine, cosmetics and daily chemical products. They have distinct highlights but also have their limitations.

Generally, when evaluating which bottle packaging to use for a product, you must first conduct a detailed analysis of the product's specific usage requirements, features, costs, etc. Then evaluate and select based on whether the characteristics of various bottle production processes meet the requirements.