pp caps are common objects in our lives. There are many kinds of raw materials with different properties. Common are polyethylene (PE), polypropylene (PP), polyester (PET), high barrier (EVOH) and so on. Polyester is the most transparent of all raw materials.

Polyester is a condensation of terephthalic acid and ethylene glycol. Non-toxic, tasteless, hygienic and safe. It can be used directly in food packaging. It has the following characteristics:

1. Good mechanical properties, impact strength is 3-5 times that of other films;

2. Resistant to oils, fats, dilute acids, dilute alkalis and most solvents;

3. High transparency, can block ultraviolet light, and has good gloss;

4. Low permeability of gas and water vapor, with good resistance to gas, water, oil and odor;

5. The heat resistance of pure PET is not high, and the heat deformation temperature is only about 85 ° C, but it is enhanced. It has since been greatly improved;

6. Good heat resistance aging, embrittlement temperature is -70℃, and it still has a certain toughness at -30℃.

Due to its good transparency, polyester is mainly used to pack mineral water and beverages in pp caps, but also for oral liquid packaging in veterinary medicine packaging. However, some special liquid drugs break down easily when exposed to light. Masterbatches are added to the bottle's raw material to make brown pp caps to better ensure the stability of the drug.

pp caps https://www.plasticsproduct.com/38mm-PP-caps.html