The quality control of the preform in the production process depends on the degree of control to avoid the preform from being scratched during the conveying process. ![]() In today's increasingly scarce oil resources, domestic manufacturers will be more inclined to preforms with long gates. The preform with a long plastic mouth is cut off due to the gate at the bottom, so that the tension is evenly distributed during the blowing process, so that the quality of the blown bottle will be better, and the cut part can be recycled, which is beneficial to save the cost of raw materials. Domestic preform manufacturers use short gate preforms more, while foreign preform manufacturers choose long gate preforms. ![]() ![]() There are two types of preforms during injection molding, one is a long gate and the other is a short gate. The quality of the bottle depends on the quality of the preforms supplied. Exhaust must be sufficient to avoid local overheating or chipping, but the depth of the exhaust port should generally not exceed 0.03mm, otherwise it is easy to produce flash. The complete process comprises the cleaning of the used PET bottles and the treatment of the recyclate so that the end product which could come in the form of flakes, pellets or preforms can meet the highest quality requirements after the recycling process. It is better to have a heat shield between the mold and the injection molding machine template, the thickness of which is about 12mm, and the heat shield must be able to withstand high pressure. The preform is generally formed by a hot runner mold. With the advantages of being unbreakable and standing on the table, it can be used to replace test tubes. Its tube wall is thick and transparent, and it can be sealed with a general plastic bottle cap. With in-house design, prototyping and tool building, adding preforms is an area of strength. The preform is the prototype of the PET bottle before it is formed. At the same time, the ability to manufacture high-quality preforms is also a manifestation of the company's strength. Because the main purpose of preforms is currently test products, the quality of preforms directly affects the success rate of the test. The production of preforms is obviously more difficult than forming large bottles. Let's take a concrete look at the preform. Only high-quality materials can be used to produce high-quality products. All products have their own characteristics and some disadvantages. The facts about PET - Author: Dr.In fact, both PET preforms and preforms are plastic products. Thermoplastic polyesters in Encyclopaedia of Packaging Technology, ed Bakker M. Today, even though the "bottle to bottle" recycling process is growing, the fibre market is still the major outlet for recovered PET. Soon however, the fibre industry discovered the "new" material source and started using it for making textiles, carpets and non-wovens. In 1977, the first PET bottle was recycled and turned into a bottle basecup. Nowadays, a 1.5 litre PET container is manufactured with just 35 grams of raw material.Īnother striking feature of PET on the environmental side is that it is fully recyclable. Throughout the years, the PET industry has increasingly taken on environmental concerns, significantly decreasing the quantity of raw material needed for the manufacture of bottles. Another advantage of the material lies in its physical properties that allow for great freedom in design. Such high pressure however, thanks to the alignment of macromolecules (crystallisation) occurring both during the resin spinning process and the blow-moulding process, is not capable of deforming the bottle nor can it make the bottle explode. Indeed, carbonated soft drinks can generate pressure inside the bottle reaching up to 6 bar. It is the strength of the material that contributes to the success of PET. The final product is, thanks to the molecular structure of the material, a transparent, unbreakable, resealable and lightweight bottle. During the blow-moulding phase, high-pressure air is blown into the preform allowing it to take the exact shape of the mould it is set into. The preform - a sort of test tube, shorter than the final bottle but with thicker walls - is then blow-moulded. ![]() The resin, in the shape of small cylinders called pellets, is melted and injected into a mould to make a preform. These two substances' derivatives (ethylene glycol and terephthalic acid) are made to react in order to obtain the PET resin. Making a PET bottle starts from the raw material: ethylene and paraxylene. The patent rights were then sold to DuPont and ICI who in turn sold regional rights to many other companies*Īlthough originally produced for fibres, PET began to be used for packaging films in the mid 1960s and then, in the early 1970s, the technique for blowing bi-axially oriented bottles was commercially developed.īottles now represent the most significant use of PET moulding resins. PET (PolyEthylene Terephthalate) was first developed for use in synthetic fibres by British Calico Printers in 1941.
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