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With the rapid development of the economy, more and more garbage is generated, and plastic packaging is causing increasing pollution to the environment, affecting human survival and development. Therefore, scientists have been committed to researching more environmentally friendly materials that can replace plastic in the past decade. Now, our company has launched several express bags made of fully biodegradable materials. What is the difference between biodegradable express bags and ordinary express bags? Today, I will explain to you:
1. Material difference: The main components of biodegradable express bags are PLA and PBAT, as well as some starch or calcium carbonate components. These materials are harmless to the environment and can be directly degraded into water and carbon dioxide under certain conditions, so they can be directly used as composting materials. The main component of ordinary express bags is polyethylene plastic. If they can be recycled and reused after use, the pollution to the environment will not be significant. However, if they are directly disposed of as garbage and buried without recycling, they cannot be degraded for decades. Even incineration can produce harmful gases. Therefore, in terms of environmental protection, biodegradable express bags are the future development direction.
2. Price difference: The cost difference between biodegradable materials and plastic polyethylene is still relatively large. Biodegradable materials currently cost around 25000 yuan/ton for raw materials on the market, while plastic polyethylene costs around 9000 yuan/ton. Therefore, in terms of cost-effectiveness, ordinary express bags have lower costs.
3. Performance difference: After more than a decade of development, the physical properties of biodegradable materials have gradually improved and can now reach 80% of the physical properties of traditional plastics. They can be used in various application scenarios. Currently, postal services, Tmall, and JD.com have begun to promote biodegradable express bags on a large scale.
Although the cost of biodegradable express bags is about three times higher than ordinary express bags now, the production process and technology are basically mature, and they are environmentally friendly, reducing pollution to the air and soil in the environment. Therefore, biodegradable express bags will become the most important development direction for future express packaging.
Standard configuration and main technical parameters
1、 Main technical parameters:
Product width range: 800-1600mm
Product thickness range: 0.02-0.15mm
Three layer co extrusion structure: top blowing method A/B/C
Total installed power: approximately 185KW
Applicable raw materials: LDPE LLDPE/LDPE mLLDPE/HDPE/fillers. Regenerate and recycle raw materials.
Dimensions (L × W × H): Approximately 9500 × 4000 × 11000mm
Maximum diameter of winding; 800MM
The maximum extrusion capacity is 350KG/hour. The conservative production of blown film is between 160-250KG/hour according to the specification size.
This device is used for blown film; Express delivery E-commerce logistics packaging materials. Consider material production costs. We need to add recycled raw materials and calcium carbonate fillers. Add a ratio between 30% and 50%. Material requirements; The adhesion of the outer printing is good. The inner layer has good heat sealing properties. Add a large amount of filling material to the middle layer. Roll it into a single sheet of film. Fold the bag in half after printing.
2、 Non standard customized configuration:
1. Extruder: Two SJ70/30 extruders, 45kw AC motor, frequency converter controlled speed regulation.
One SJ65/30 extruder, 37kw AC motor, frequency converter controlled speed regulation.
1.1 Screw structure: The screw is specifically designed with a shear section, barrier section, and mixing section to reduce pressure and yield fluctuations and improve the uniformity of the melt. Applicable to the compatibility of mixed raw materials and fillers.
1.2 Screw diameter: Φ 70mm/1 Φ 65mm/2
1.3 Screw speed: 15-90rpm
1.4 Screw surface hardness: HRC56-60.
1.5 Screw barrel material: 38CrMoALA high-quality alloy steel, processed by hot melt+curing aging process, surface treated with nitriding, wear-resistant and corrosion-resistant.
1.6 Surface hardness of the barrel: HRC60-62.
1.7 The body adopts a stainless steel heating system
1.8 Barrel heating section: 5 sections.
1.9 Barrel heating power 30KW
1.10 Cooling method for the barrel: automatic air cooling for overheating, water cooling for the feeding section.
1.11 Quick screen changing device: The screen changing area is automatically sealed without any leakage, making it convenient and efficient to replace the filter screen, saving time and effort. Specialized enlarged mesh board. Dual station manual pulling type.
1.12 Quick change part heating power: about 4kw.
1.13 Intelligent Melt Pressure Display: Digital LCD displays the melt pressure inside the extruder and monitors the working status of the extrusion system in real time.
1.14 Digital LCD Temperature Control Meter: The digital LCD displays the set temperature and actual temperature of each temperature control section, making operation intuitive and convenient.
1.15 Gear reducer: The gears have undergone hardening treatment and surface grinding, resulting in smooth transmission with characteristics such as low noise, high speed, high torsion, and wear resistance.
1.16 Deceleration method: The gearbox is used for deceleration, and the transmission ratio is reasonable. 1 unit 225/2 units 200
1.17 Transmission mode: direct drive.
1.18 Drive motor: 37KW/45kw motor, runs smoothly and has good heat dissipation effect.
1.19 Speed Control Method: Variable frequency drive controls speed control, which is efficient, energy-saving, precise, sensitive and reliable in speed control.
1.20 hopper: made of 50kg stainless steel.
1.21 Contactor and air switch: Zhejiang "Chint".
1.22 Frequency converter: extruder specific vector/winding tension feedback.
2. Three layer co extrusion internal cooling mold and air ring<specialized high-capacity customized structure>
2.1 Mold design is based on the performance of recycled raw materials and fillers. And extrusion output and pressure. Reasonably improve and enhance the flowability of raw materials and the distribution of shear heat, to avoid excessive mold pressure and thermal hysteresis. The membrane bubbles shake unstably. This will affect the reduction of production capacity. Improve the uniformity of thickness in the production of thin film products; The design structure of the flow channel is smooth and free of dead corners. The flow channel is finely ground and polished before being plated with hard chromium, resulting in a high surface smoothness and good transparency and glossiness of the produced thin film products.
2.2 New high-efficiency cooling air ring: The optimized design of the new air ring ensures uniform and stable air volume adjustment, providing extremely high cooling effect and film bubble stability, thereby ensuring high extrusion yield, good transparency, and film bubble stability.
2.3 Mold processing: Independent precision processing is completed by a precision four axis linkage machining center to ensure the machining accuracy of the mold and the uniformity of material distribution in each layer.
2.4 Mold specification: Φ 320
2.5 Mouth mold gap: 2.3mm
2.6 Mold Material: 40Cr
2.7 Heating method: Strip shaped high-temperature resistant stainless steel heating ring.
2.8 Wind ring material: cast aluminum alloy material.
2.9 Heating power: approximately 25kw.
2.10 Temperature control section: 5 sections.
2.11 External cooling fan: 18.5kw fan, frequency converter controlled speed regulation.
2.12 The IBC membrane bubble cooling device consists of an inlet device that provides cold air flow to the inside of the membrane bubble and an exhaust device that discharges hot air flow.
2.13 Membrane Bubble Detection System: A digital bubble diameter detection system consisting of three ultrasonic sensors (produced in Germany).
2.14 PLC Bending Control System: Adopting PLC control, the air volume is adjusted by adjusting the fan speed, with high control accuracy and small deviation in membrane bubble bending diameter.
2.15 Internal cooling fan: Both the inlet and outlet fans are 7.5kw fans with variable frequency control.
3. Traction rotating auxiliary machine: tower mechanism.
3.1 Stable Bubble Rack: Aluminum guide roller type stable bubble rack, which can be radially adjusted according to the size of the film bubble to avoid radial shaking of the film bubble.
3.2 Aluminum alloy guide roller type herringbone plate: The guide roller is in rolling contact with the film bubble, with low friction and few scratches, providing good performance
Film flatness.
3.3 Side guide roller: It plays a stabilizing role on the side, preventing the film from moving along the axial direction of the traction roller and ensuring that the film is wound neatly.
3.4 Traction rotary drive motor: 750W AC motor, frequency conversion control.
The action of the traction rotating part is controlled by the forward and reverse travel switches.
3.6 Rotation method: Horizontal swing rotation, 360 degree reciprocating rotation.
3.7 Rotation speed: 7-10 minutes per revolution, adjustable speed.
3.8 Upper traction clamp: composed of an active roller (steel roller) and a passive roller (rubber roller).
3.9 First traction roller clamping method: pneumatic clamping control.
3.10 Drive motor and its control: 2.2kw AC motor, frequency conversion control.
3.11 Traction speed: 5-50 meters per minute
3.12 Transmission mode: Adopting direct transmission instead of sprocket and chain transmission, it runs smoothly and has constant tension. Fundamentally
Eliminating the impact of speed fluctuations caused by chain shaking on film tension.
3.13 Air cushion roller: The external air cushion prevents direct contact between the film and the air cushion reversing roller, avoiding scratches on the surface of the film.
3.14 Guide roller: Made of aluminum alloy material, calibrated for dynamic balance.
3.15 Flattening roller: an arc-shaped flattening roller that flattens the film surface without folding.
3.16 EPS Ultrasonic Correction System: Automatic correction guidance to ensure neat film winding.
3.17 According to customer needs, reserve installation positions for corona treatment machines for easy operation and maintenance.
Winder: Dual station passive friction automatic roll changing, A and B winding parts can be adjusted separately.
4.1 Winder drive motor: 2.2kw AC motor, frequency converter controlled speed regulation.
4.2 Second traction drive motor: 2.2kw AC motor, frequency converter controlled speed regulation.
4.3 Second traction pinch roller: pneumatic control.
4.4 Winding speed: 5-50 meters per minute
4.5 Maximum bending diameter: 1800mm
4.6 Maximum roll diameter: Φ 800mm.
4.7 Cutting device: The film can be cut into multiple films online according to the product specifications.
4.8 Length Calculation Device: When the film roll reaches the set length, the electric whistle will automatically sound an alarm to remind to change the roll.
4.9 Inflatable scroll: 4 pieces.
4.10 Tension closed-loop control system: A new automatic tension control system is adopted to achieve automatic tension adjustment based on the measured tension changes of the film, ensuring a constant winding tension of the film.
4.11 Flying knife cutting, automatic roll change.
5. Electrical control system:
5.1 Extruder control cabinet: Monitor and control the processing temperature, screw speed, current, and other working conditions of three extruders separately.
5.2 PLC control system.
Note: This configuration does not include auxiliary machinery such as automatic feeder, mixer, air compressor, edge feeder, corona generator, and cold water system.
