Physical and chemical properties of the bulk bag

Let’s talk about the materials used in the production of the bulk bags in detail, as well as the physical properties and general chemical properties of various materials. Thank you.

What is the material of the bulk bag?

Two materials, polypropylene, polyethylene, polypropylene is a thermoplastic resin made by polymerization of propylene

Polypropylene is a non-toxic, odorless and tasteless milky white high crystalline polymer with a density of only 0.90 — “0.91g/cm3. It is one of the lightest plastics at present.

Polypropylene has good heat resistance. The products can be sterilized at a temperature above 100 ℃ and will not deform at 150 ℃ without external force. Due to the large shrinkage rate (1% ~ 2.5%), thick wall products are easy to sag, and it is difficult to meet the requirements for some parts with high dimensional accuracy and good surface gloss. It is very stable for water. Its water absorption is only 0.01%, and its molecular weight is about 80.15 million.

Polyethylene is generally a thermoplastic resin made of ethylene by polymerization.

Polyethylene is odorless, non-toxic, waxy and has excellent low-temperature resistance (the minimum operating temperature can reach – 100 ~ – 70 ° C). High-density polyethylene (HDPE) is commonly known as low-pressure polyethylene. Compared with LDPE and LLDPE, it has higher temperature resistance, oil resistance, steam permeability resistance and environmental stress cracking resistance. In addition, it has good electrical insulation, impact resistance, and cold resistance

Processing technology

Generally, these two kinds of raw material particles or powder are purchased in the production of the bulk bags. They are heated and stirred in the factory formula, drawn and shaped, then cut into the required raw silk, and then spun into the required or commonly used bulk bag base cloth by using a circular loom for standby

If you customize bulk bags, you can cut and sew these textiles forming base cloth into various specifications of the bulk bags. Generally, most of them are made of polypropylene. Occasionally, high-pressure polyethylene is used by companies that produce plastics or raw materials. The outer edge of bulk bag is generally coated with low-pressure polyethylene film to achieve the purpose of waterproof, so the basic material of the bulk bag is For those with these materials, it is generally necessary to add some other auxiliary materials to the ingredients in the production process.