After a long-term development of the domestic plastic ( disposable bottle ) profession, a relatively good system has been formed, and a new type of data industry has now formed. Especially after entering the 21st century, China's plastic profession has achieved It has achieved a remarkable performance. The growth rate of the plastics industry has always been maintained at a very high level, and then has driven the continuous rise of economic benefits of enterprises. Analyzing from the production quantity of plastic products, the development trend of China's plastics industry is very strong.
Plastic packaging materials include flexible packaging, woven bags, hollow containers, turnover boxes, etc., which is one of the most extensive areas in the use of plastic products. Plastic packaging accounts for about 1/3 of the total output of the packaging materials market, and plastic packaging ranks first in all kinds of packaging materials. Various mineral products, chemical products, grain, sugar, cotton, etc. are now widely used in plastic packaging; due to the development of beverages, cleaning supplies, cosmetics, chemical products, etc., then there is a huge demand for plastic packaging materials. The corresponding plastic packaging occupation requirements for food and medicine are even more popular, and it is beyond doubt that the rapid development of plastic occupations will be promoted.
PET plastic bottles exist in your daily life. Whether it is plastic bottles for water and beverages or soy sauce bottles for cooking, PET plastic bottles are mainly food plastic bottles. PET plastic bottles are also available. Classified, for example, plastic bottles containing carbonated beverages are pressurized plastic bottles, and non-pressure plastic bottles containing water or oil are non-pressure plastic bottles. Each type of plastic bottle has a certain molding process. That is blow molding. Below I will introduce the blow molding process of PET plastic bottles.
The main elements of PET plastic bottle blow molding involve preform, heating, pre-blow, mold and environment.
When PET plastic bottles are blown, PET chips are first formed into preforms. This step requires that the materials recovered in the second time should not be too high, and the number of times of recovery should not be too much. Generally, it should not exceed two times, and the molecular weight should be 31,000-50000 The viscosity should be between 0.78-0.85 cm3 / g. The preforms for injection molding must be stored for more than 48 hours before they can be used. The storage time of the preforms must not exceed 6 months.
The preform is then heated. This process is completed by a heating oven. The temperature is determined by confirmation. The lamp tube in the oven is generally in the shape of a "zone" with more ends and less center. The heat is generated by the lamp. The number of tubes is used to confirm that the preform can rotate while moving forward in the oven. The purpose is to make the preform heated evenly.
Pre-blowing is a very important process in the two-step bottle blowing method. It is necessary to blow air while the stretching rod is lowered. In this link, the effects of the three factors of pre-blowing orientation, pre-blowing pressure and air flow rate, pre-blowing The shape of the bottle depends on the function of the bottle. The normal bottle has a spindle shape, and the abnormal shape is generally dumbbell-shaped or handle-shaped.
The mold is a device to maintain product stability. The constant temperature of the mold is very important. It is the main factor for maintaining product stability. The shape of the mold can increase or decrease the difficulty of processing.
The quality of the production environment also has a great impact on the process adjustment, and stable conditions can maintain the stability of the process.
The PET plastic bottle molding process can directly affect the appearance of the plastic bottle and its own functions, so every element of every link must be paid great attention.