Processing technology of PET bottle sheet

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PET bottle chip processing technology

the rapid growth of PET bottle consumption, the improvement of collection system and the changes in regulations in Europe provide new opportunities and challenges for the rapidly developing PET recycling industry

many products use recycled materials to replace pure materials, creating economic and processing technical significance. They are commonly used fibers, thermoformed sheets, nonwoven fibers, packaging belts, and even masterbatch and bottles

each of these processes puts forward requirements for the properties of recycled PET materials, which is close to the requirements for pure materials. In addition to molecular weight (often referred to as intrinsic viscosity), particles or pollutants in the melt (such as paper, sand, glue, PP, PVC and other plastics) will affect the product quality

the highest quality requirements appear in the so-called "bottle bottle" recycling process. In this case, the process is practical and economically feasible only when the source of the used bottles is determined and controlled, such as the backlog of recycled bottles

if the bottles used are from household plastic waste, there is a risk of unknown pollutants. It will also require highly complex sorting and cleaning plants, increasing the cost of bottle flakes

at present, the collection, packaging, sorting, grinding, cleaning, drying, extrusion, filtration, chipping and solid-state polymerization processes of PET bottle flakes have created possibilities for efficiency improvement and cost savings. An important trend is to reduce production costs by directly processing the cleaned and dried bottle flakes into the above products, eliminating the intermediate step of extruding PET bottle flakes into pellets or flakes

pet bottle chips are directly processed into the above products, which makes the production process vulnerable to interference. Filtering is particularly important. The filtration system must be able to deal with the changing pollution load, must operate automatically and make effective use of the filter medium. Of course, its operation must also have a high level of process stability

next, several most important problems and influencing factors related to PET bottle sheet processing will be discussed, and possible solutions and suggestions on how to deal with each problem will be put forward. Emphasis is placed on this aspect of melt filtration

when processing pet bottle flakes, many interference factors may appear, causing further problems. The following table gives a brief overview of the main interference factors in PET bottle sheet processing

A) PET bottle resin the best material quality is needed to further process the PET bottle sheet into bottle resin. Assuming that the debris cleaning and finishing process operates efficiently, there are still many process and technical requirements to be met in order to obtain debris with the same quality as pure material. The following aspects are some examples: optional pre drying, plastic blowing industry dominated by plastic film blowing machine with or without vacuum has a large proportion in the market, extrusion, melt filtration, scrap cutting, crystallization and ssp


because the melting time of pet must be absolutely minimum, the filtration system is very important

in order to remove visible pollutants, the filtration fineness must be between 25 and 50mm. The particles of burnt paste must not appear in the final product from beginning to end, including the replacement of filter elements and self-cleaning of filter elements. Of course, the filtration system must also be able to automatically adjust itself to deal with the changing pollution load, which is an important feature of the fully automatic melt filtration system RSFgenius

b) a-pet sheet using PET bottle sheet is a very attractive method for thermoforming sheet manufacturers to reduce their raw material cost. The filtration system is also crucial in this case: the sheet must be free of visible defects (black spots, fish eyes, etc.). When the distance between the allowable wire and the ground should be more than 150 cm, the melt filtration occurs after the gear pump, and the filtration system with stable pressure is important. Because of the heavy cost pressure, the melt filtration system must be fully automatic, and the use efficiency of the filter is high, and the material loss caused by self cleaning (back flushing) is small

RSFgenius melt filtration system meets such requirements. The filter fineness varies with the application, but it is usually between 20 and 200mm

C) locally oriented yarn, fixed length fiber

when the recycled rubber particles are drawn or bottle fragments are used as feed, different processing principles work: the high-speed drawing process of producing locally oriented yarn requires 0 Intrinsic viscosity of 64 DL/g. The bottle fragments can be pre dried. 2. Before the experiment, the maximum load of the experiment should be estimated or controlled, and the inherent viscosity regulator should be added to control the inherent viscosity. In order to produce a completely gray or semi gray appearance, Ti02 additive is also required

in order to prevent the spinneret from clogging too early, efficient melt filtration is essential. The required

filtration fineness is generally 20mm or finer

fixed length fiber is at 0 It is drawn at a slightly lower intrinsic viscosity of 62dl/g. In this case, the intrinsic viscosity is also determined by the degree of pre drying and the addition of intrinsic viscosity regulator. Effective filtration is very important for the economic efficiency of operation by preventing premature blockage of the filter. The typical filtration fineness is 36mm

d) packaging tape material, high tensile monofilament

; High tensile packaging tape is extruded and stretched unidirectionally. Single filaments are drawn out after melt spinning. Because this product has high inherent viscosity and relatively thick cross-sectional area, the filtration fineness is usually between 70mm-120mmp. Larger foreign particles reduce the tensile strength of the packaging belt. Moreover, the pressure stabilizing mode of filtration system operation is a decisive aspect, because the necessary dimensional stability is very important for in-depth processing and tensile strength

the use of PET bottle flakes has an important impact on the production of packing belt and tear resistant monofilament. The purpose is to keep the cost of raw materials as low as possible, especially because the recycled materials can be used without problems, as long as the production line is designed accordingly. So far, the intrinsic viscosity value is about 0 3% pure pet will be mixed. The mixing rate is related to the required strength of the packing belt and the quality and humidity of the crushed material. Moreover, the design of production line plays an important role. The application possibility of PET bottle scrap is particularly determined by the consistency and fineness of the filtration system used. It is also possible to increase the intrinsic viscosity of the crushed material to 1.0 and higher, so that the recycled material can be used 100%

reprinted from: International Plastics Industry


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