Kako provjeriti kvalitetu PET kalupa za predformu?
Danas, Zhangjiagang Eceng Machinery Co., Ltd proizvođač strojeva za puhanje za kućne ljubimce govori vam kako riješiti kvalitetu PET kalupa za predformu:
One, what is PET
PET is a kind of polyester, which is the abbreviation of English Polyethylene Terephthalate, and its full Chinese name is polyethylene terephthalate.
Characteristics of the raw material: the transparency is as high as 90 percent or more, the surface gloss is excellent, and it has a glass-like appearance. Excellent fragrance retention and good air tightness. It has good chemical resistance and is resistant to almost all organic chemicals, including acids. Good hygiene, PDA-recognized by the Department of Chemical Testing in the United States. No poisonous gas will be generated during combustion. It has excellent strength properties, and various properties can be further improved by biaxial stretching.
2. Why do PET raw materials need to be dried before producing preform molds?
Remove the water in PET, because PET has a certain degree of water absorption, it will absorb a lot of water during transportation, storage and use. The high content of water will be exacerbated in production: the increase of acetaldehyde. The influence on the odor of the beverage bottle leads to a decrease in the viscosity of the beverage which tastes bad (but has little effect on the human body). It has an impact on the pressure resistance of the beverage bottle and is easy to break. (Essentially caused by the hydrolytic degradation of PET, prepare high temperature for PET into the injection molding machine for shearing and plasticizing
Third, the water absorption characteristics of PET: the water content of the raw material particles is usually in the range of 0.1-0.3 percent (1000 to 3000 ppm).
Fourth, the main points of PET drying
Dry setting temperature, residence time? 4-6 hours, discharge port temperature? Dew point above 160oC? Below -30oC, drying air flow rate? 3.7m3/h
5. Degree of dryness
1. The ideal moisture content after drying is approximately: 10 to 40 ppm ( plus /- 10 ppm), that is
2. Excessive drying will also increase:
3, increase in acetaldehyde
4. The decrease in viscosity is essentially caused by the oxidative degradation of PET.
