Pioneering innovation of WSJP95‐1200PET twin-screw sheet extrusion equipment

Yang Weiguang Zhang Junbo Li Yiming
(Guangdong Dacheng Technology Co., Ltd.)

Abstract: This article introduces the market demand and production process status of domestic PET extrusion sheet equipment in recent years, and details the main features and key technologies of the existing PET crystallization-free drying twin-screw extrusion sheet equipment Finally, the application prospect of the device is explained.

Key words: PET twin-screw; crystallization-free drying; screw combination; vacuum exhaust; spiral flow channel technology.

WSJP95‐1200PET twin screw extruder equipment exploration and innovation

Yang Weiguang Zhang Junbo Li Yi
(Guangdong Dacheng Technology Limited by Share Ltd )

Abstract:This paper introduced domestic PET extruder’s market request and present process in recent years. Expand the existing PET free crystallizing drying extruder equipment’s key feature and technologies and the application prospect.

Keywords: PET twin screw extruder; free crystallizing drying; screw assemble; vacuum exhaust; spiral channel technology.

Foreword

In recent years, as many foreign advanced plastic sheet extrusion equipment entered China, domestic sheet packaging equipment manufacturers are also rapidly emerging, promoting the rapid development of the sheet packaging industry and the increase in equipment demand. With the continuous increase, people put forward higher requirements for the output, energy consumption, environmental protection and automation of equipment. Guangdong Dacheng Technology Co., Ltd. has concentrated its superior resources and jointly developed with many advanced suppliers and research institutes at home and abroad. On the 95 model, it has successfully developed a WSJP95-1200 twin-screw with a high output of 1200 kg PET per hour. Sheet extrusion unit Extrusion sheet extrusion equipment has created high-end twin-screw extrusion sheet extrusion equipment in China. It has the characteristics of low energy consumption, simple process, and convenient equipment use and maintenance. It is currently the most advanced technology, mature technology and stable equipment in China. The production line equipment of the film was delivered to the customer for verification and use, and the effect was very satisfactory. This paper introduces the green performance characteristics of WSJP95-1200PET twin-screw sheet extrusion unit extrusion sheet extrusion equipment, green innovation of production process, key structural technology and control technology innovation, and points out that high output, low energy consumption, environmental protection, automation, intelligence It is the main feature of the sustainable development of PET twin-screw extrusion sheet extrusion equipment.

WSJP95-1200PET twin-screw extrusion sheet extrusion machine

1 Green performance characteristics of WSJP95-1200PET twin-screw extrusion sheet extrusion equipment

Compared with the domestic similar equipment, the WSJP95-1200PET twin-screw extruding sheet unit has an overall energy saving increase of more than 30-40%. (The domestic similar equipment is 95 models, the general output is 500 kg per hour, while the output of new products developed by Dacheng is 1200 kg per hour); three-stage vacuum exhaust technology and oil and gas separation technology are adopted, eliminating the need for a crystallization drying system. It not only reduces the footprint of the equipment, but also reduces the energy consumption; the use of twin-screw optimized combination technology greatly reduces the viscosity reduction of PET and ensures product quality and stability.

Ethylene-vinyl alcohol copolymer, referred to as EVOH, is known as the world's three largest barrier resins together with polyvinylidene chloride (PVDC) and polyamide (PA) [2]. EVOH can greatly inhibit the intrusion of oxygen in the air into food, thereby inhibiting the production of toxins and other harmful substances due to the proliferation of microorganisms, and can also prevent composition changes caused by oxidation, while maintaining fragrance and preventing external odor pollution. Moreover, the lack of moisture barrier properties can be compensated by other polyolefin layers. Therefore, EVOH multilayer packaging materials can effectively prevent food spoilage and extend shelf life. In addition, it is easy to process and form, and has good environmental protection performance. Due to the excellent gas barrier properties, transparency, processability and solvent resistance of EVOH resin, its application fields are getting wider and wider, and the demand is also growing rapidly.

1.1 Main technical parameters

Twin screw combination structure, screw diameter 95MM; maximum extrusion output: 1200kg/h; product width: 1000MM; thickness: 0.12-1.8MM; installed capacity: 430KW, actual energy consumption 250KW.

1.2 Features of green processing technology

Adapt to a variety of raw materials: PET, PLA, new materials, recycled materials, color masterbatch;

The multi-component feeding device technology is suitable for the control of the proportion of new material, returned material, color masterbatch, etc.;

Crystallization-free drying technology for raw materials, low overall energy consumption of the unit, and cost saving;

High-torque extrusion unit, equipped with a torque protector; equipped with a melt filter with a large filter area, which saves a lot of time and labor consumption for screen changing operations;

The three-roller calendering roller press adopts hydraulic device, with compact structure, convenient arrangement of auxiliary facilities and simple operation;

Online trimming, crushing, conveying and recycling system, special winding structure design, realize online non-stop coil change, unloading device, saving a lot of operating time and labor consumption;

On-line silicon coating system to improve sheet adaptability and protection, and improve competitiveness;

The high-precision twin-screw extrusion system adopts pressure closed-loop feedback control technology, temperature double PID control technology for heating and cooling, etc.;

The whole machine adopts PLC control to realize automatic control of parameter setting, data operation, feedback, alarm and other functions;

Advanced dual PID control algorithm technology, real-time statistical analysis of technical data, and real-time improvement measures are provided to ensure that the production process is always in a state of statistical control to improve product quality, accuracy, energy consumption and other performance indicators.

2 Green innovation of production process of WSJP95-1200PET twin-screw extrusion sheet unit

PET sheet is a new type of material developed in recent years. With its excellent toughness, high hardness, high transparency, non-toxic, odorless, easy to shape and recyclable, and the excellent environmental performance of burning no harmful gas, Complying with the trend of environmental protection, it has gradually been greatly favored by consumers and producers, and is widely used in product packaging, stationery, printing, gifts and crafts in all walks of life.

The high moisture content of ordinary PET raw materials in the air will cause hydrolysis during melt extrusion, which will significantly reduce the melt viscosity and molecular weight, resulting in abnormal phenomena such as foaming, brittleness, and yellowing of the extruded sheet. At present, the domestic equipment to solve the moisture content of raw materials to produce PET sheet mainly includes single-screw extruder, and its processing route of "pre-crystallization-drying-melt extrusion" generally needs to be equipped with a crystallization drying system. The second is a planetary screw (multi-screw) crystal-free extruder, which is a drying-free direct exhaust extrusion process, and the third is a twin-screw crystal-free drying extruder, which is also directly extruded by a vented extruder. .

The crystallization-free drying direct vent extrusion process has attracted much attention due to its remarkable energy-saving effect. At present, there are single-screw and twin-screw crystal-free, planetary screw (multi-screw) crystal-free and other types. Due to the inherent characteristics of single screw, it is suitable for the requirements of professional manufacturers with few production varieties. The production conditions of different raw materials need to be matched with special screw structures. better efficiency. Planetary screw (multi-screw) crystallization-free drying extruders are generally suitable for PVC saliva pressing production lines. For PET raw materials, it is difficult to take into account the different proportions of new materials and returned materials. In actual production, there is still the risk of exhaust and material leakage, which is more difficult. In order to achieve the ideal exhaust effect and effectively control the final viscosity of the PET melt, the structure of the planetary screw (multi-screw) exhaust extruder is becoming more and more complicated, which brings a lot of inconvenience to subsequent processing, assembly and maintenance. , At present, there are no articles with detailed data reports and equipment popularization.

WSJP95-1200PET twin-screw extrusion sheet unit twin-screw crystallization-free drying extrusion process has several significant advantages, including obvious energy-saving effect, simple process and process, and can realize online compounding, etc. Through the special transformation of twin-screw, the ideal Effective venting effect and effective control of PET melt viscosity control.

3 WSJP95‐1200PET twin-screw extrusion sheet unit key structural technology and control technology innovation

How to develop PET high-efficiency sheet extrusion equipment, through multi-party demonstrations, it is believed that technological innovation, structural optimization, and precision manufacturing from five links can achieve high output and low energy consumption of the equipment, and build high-efficiency twin-screw sheet extrusion equipment in China. . :

3.1 Twin-screw combination technology

The double-screw configuration R&D and design experience accumulated over the years is optimized and combined with advanced software technology. The special double-head screw element and the unique screw combination can realize conveying and plasticizing, mixing and kneading, shear dispersion, homogenization and homogenization, and exhaust. Various functions such as devolatilization, pressure building and extrusion. Especially in the removal of crystal water inside the PET material, it has extremely high efficiency. The specially designed exhaust port is free and unobstructed, so as to realize low temperature extrusion and avoid thermal degradation of PET;

3.2 Vacuum exhaust technology

The multi-stage forced exhaust is efficient and safe to ensure that the PET material will not be hydrolyzed and crystallized during the melting and plasticizing process. Special three-stage vacuum exhaust technology and oil and gas separation technology, large air extraction volume and ultra-high vacuum degree, greatly reduce the viscosity reduction of PET.

3.3 High-strength roller internal spiral flow channel technology

The internal spiral flow channel structure design of the high-strength roller is matched with the water temperature control system, so that the roller has precise temperature control and efficient heat transfer effect;

3.4 Intelligent remote control technology

Through the company's server IDC center industrial data center and industrial data collection and analysis software, remote monitoring network equipment, standard motor health detection and analysis system, equipment energy management optimization system, etc. Process data collection and storage, and process data analysis to optimize the production process formula.

3.5 The spirit of craftsmanship in equipment manufacturing