At present, many glass bottle packaging containers are equipped with plastic caps. There are many differences in the structure and material of the positive and negative pressure protectors. In terms of materials, they are generally divided into PP and PE types.
PP material: It is mostly used for gas beverage bottle cap gaskets and bottle caps. This material has low density, heat resistance and no deformation, high surface strength, non-toxic and harmless, and good chemical stability. The disadvantage is poor toughness and low temperature conditions. Easily embrittled, and it is not wear-resistant due to poor oxidation resistance. Bottle caps of this material are mostly used for fruit wine and carbonated beverage bottle cap packaging with water sealers.
PE material: It is mostly used for hot-filling bottle caps and aseptic cold-filling bottle caps. This material is non-toxic, has good toughness and impact resistance, is also easy to form film, is resistant to high and low temperatures, and has better environmental stress cracking performance Good, the disadvantage is that the molding shrinkage is large and the deformation is severe. Many vegetable oils on the market, and sesame oil in glass bottles are mostly made of this material.
Plastic bottle caps are generally divided into gasket type and inner plug type. The production process is divided into compression molding and injection molding.
The sizes are mostly: 28 teeth, 30 teeth, 38 teeth, 44 teeth, 48 teeth, etc.
The number of teeth is divided into: 9 and 12 multiples.
The anti-theft ring is divided into 8 buckles, 12 buckles, dehydrator, etc.
The structure is mostly: separate connection type (also called bridge type) and one-time forming type.
Uses are generally divided into: gas bottle caps, heat-resistant bottle caps and sterile bottle caps, etc.
Due to the low cost of plastic materials, the desulfurization tank combines the advantages of many materials, and it is also welcomed by packaging container material factories to a certain extent. However, because its structural change performance is not very clear, it must be applied in some food packaging fields. Consider it, but with the development of science and technology, the application of plastic covers in the field of food packaging will become more and more extensive.