What are the recycling characteristics of PET?

What are the recycling characteristics of PET?

PET material is a recyclable thermoplastic material that can be processed by SSP to achieve a quality equivalent to resin. Nowadays, waste plastic bottle scraps have been successfully used in the production of food-contact packaging, high inherent viscosity (IV) strapping, and long-thread fibers. Recycling production from “bottle to bottle” requires extremely high standards in terms of decontamination. Due to the outstanding properties of this material, PET (polyethylene terephthalate) has been used successfully in the production of food-contact packaging. However, this has led to more PET waste, which has increased the public’s attention to this issue. Recycling technology has made a significant contribution to the positive recognition of PET packaging: it raises ecological awareness, promotes the recycling of waste products, and the mandatory reuse of recyclable PET materials. At present, key enterprises with large brands are also following this trend and vigorously advocating the reduction of carbon emissions and the protection of resources. According to forecasts, the world’s consumption of PET bottles will double in the next ten years. Even with a large recycling rate, the main part of PET waste will still be landfilled as garbage. The cleaned and processed PET can become a valuable renewable resource. In this context, to contribute to the recycling of resources and actively accept products made of rPET materials has become an unshirkable responsibility of customers-plastic bottles of this material can be converted into fibers, filaments and nonwovens Cloth, plastic board, strips, and the most important one, which is once again transformed into recycled plastic bottles. Scraps from production waste, as well as used preforms, plastic bottles and plastic plates, can be recycled and processed into granular raw materials, or they can be transformed into final products through online processing. Whether it is processed separately or on-line, PET scraps are decontaminated, and the intrinsic viscosity (IV) of the material is also improved. In production, it is used in combination with recycling extrusion equipment and pelletizing system. The optional upstream or downstream vacuum SSP reactor can ensure the quality of rPET to reach an excellent level. The application of this material on the production line enables energy saving and value-added to be realized in a “one-step” way.

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Introduction to the process of making acrylic panels

In the field of plastics, acrylic refers to polymethyl methacrylate, or PMMA, which is a thermoplastic engineering plastic with excellent comprehensive properties. It is mostly used for outdoor and indoor signs in the form of sheets. In the application industry, its materials generally appear in the form of particles, plates, pipes, etc.

Acrylic panels are divided into cast panels and extruded panels according to the production process. According to the transmittance, they can be divided into transparent panels and semi-transparent panels (including dyed transparent panels); according to performance, they are divided into impact-resistant panels, UV-resistant panels, and color panels (including Black and white and color boards), ordinary boards and special boards such as high impact board, flame retardant board, frosted board, metal effect board, high wear-resistant board, light guide board, etc.

Extruded plate: Compared with the cast plate, the extruded plate has a lower molecular weight, slightly weaker mechanical properties, and higher flexibility. However, this feature is conducive to bending and hot forming processing, and the softening time is shorter. When processing large-size plates, it is beneficial to various rapid vacuum forming. At the same time, the thickness tolerance of the extruded plate is smaller than that of the cast plate. Since the extrusion plate is mass-produced automatically, the color and specifications are inconvenient to adjust, so the variety of product specifications is subject to certain restrictions

Casting plate: high molecular weight, excellent rigidity, strength and excellent chemical resistance. Therefore, it is more suitable for processing large-size identification plaques, and the time in the softening process is slightly longer. This kind of board is characterized by small batch processing, incomparable flexibility in color system and surface texture effect, and complete product specifications, which can be used for various special purposes.

There is also a kind of recycled acrylic sheet, which uses recycled acrylic scrap, which is thermally degraded to obtain recycled MMA (methyl methacrylate) monomer, which is then obtained by chemical polymerization. After a rigorous process, the pure MMA monomer can be re-obtained, and there is no difference in quality from the newly synthesized monomer. However, the purity of the degraded monomer produced is not high, and the quality and performance of the sheet are poor after it is formed.

The extruded plate uses granular raw materials and is extruded after being dissolved at high temperature. The casting plate is directly casted with MMA monomer (liquid). Although the extruded plate is relatively flat and smooth in appearance, it can be completed when the granular raw material is formed. polymerization. When processed into plates, its structure and performance are weak, and it is not suitable as a material for outdoor marking products. It is only suitable for indoor products such as crystal letters or product brackets. In addition, since most of the extruded panels do not have the function of UV protection, their outdoor use life is not the same as that of the cast panels. The color will gradually fade and it is easy to become brittle until it breaks. The casting plate is to complete the structural polymerization during the processing of the plate, during which the ultraviolet absorber is added, which has extremely high strength and UV function. The outdoor service life is more than 4 years or even 10 years, and the color is always bright as new during use.

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The production process of PVC pipes

PVC plastic is a kind of multi-component plastic, and different additives can be added according to different uses. Due to different components, PVC products show different physical and mechanical properties, and are used for different occasions. Competitiveness.

In the production of hard pipes, SG-5 resin with a lower degree of polymerization should be used as the resin. The higher the degree of polymerization, the better its physical and mechanical properties and heat resistance, but the poor fluidity of the resin brings certain difficulties to processing, so the viscosity is generally selected. SG-5 type resin of (1.7~1.8)×10-3Pa•s is suitable. Hard pipes generally use lead-based stabilizers, which have good thermal stability. Tribasic lead is commonly used, but it has poor lubricity. It is usually used in combination with lead and barium soaps with good lubricity. When processing hard pipes, the choice and use of lubricants are very important. It is necessary to consider internal lubrication to reduce the intermolecular force and reduce the viscosity of the melt to facilitate molding, and to consider external lubrication to prevent the melt from adhering to the hot metal and make the surface of the product. bright.

The filler mainly uses calcium carbonate and barium (barite powder). Calcium carbonate makes the surface of the pipe good. Barium can improve the formability and make the pipe easy to shape. Both can reduce the cost, but too much use will affect the performance of the pipe. And the corrosion-resistant pipe is best to add no or less filler.

In the production process, because PVC is a heat-sensitive material, even adding heat stabilizers can only increase the decomposition temperature, and prolong the stabilization time without decomposition. This requires that the molding temperature of PVC should be strictly controlled. Especially RPVC, because its processing temperature is very close to the decomposition temperature, the decomposition phenomenon is often caused by improper temperature control. Therefore, the extrusion temperature should be determined according to factors such as the formula, the characteristics of the extruder, the structure of the die, the screw speed, the location of the temperature measuring point, the error of the temperature measuring instrument and the depth of the temperature measuring point.

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What is PVC film?

PVC, the full name is Polyvinylchloride, the main component is polyvinyl chloride, and other components are added to enhance its heat resistance, toughness, ductility, etc. The top layer of this surface film is lacquer, the main component in the middle is polyvinyl chloride, and the bottom layer is back-coated adhesive. It is a kind of synthetic material that is well-loved, popular and widely used in the world today. Its global usage ranks second among various synthetic materials. According to statistics, in 1995 alone, the production of PVC in Europe was about 5 million tons, while its consumption was 5.3 million tons. In Germany, the production and consumption of PVC is an average of 1.4 million tons. PVC is being produced and applied worldwide at a growth rate of 4%. The growth rate of PVC in Southeast Asia is particularly significant, thanks to the urgent need for infrastructure construction in Southeast Asian countries. Among the materials that can produce three-dimensional surface films, PVC is the most suitable material.

PVC material is polyvinyl chloride. It is one of the largest plastic products in the world. It is cheap and widely used. Polyvinyl chloride resin is white or light yellow powder. It cannot be used alone and must be modified. PVC is a white powder with an amorphous structure, with a small degree of branching, and poor stability to light and heat. Different additives can be added according to different purposes, and PVC plastics can present different physical and mechanical properties. Adding an appropriate amount of plasticizer to the polyvinyl chloride resin can be made into a variety of hard, soft and transparent products. PVC can be divided into soft PVC and hard PVC. Among them, hard PVC accounts for about 2/3 of the market, and soft PVC accounts for 1/3. Soft PVC is generally used for floors, ceilings and the surface of leather, but because soft PVC contains softener (this is also the difference between soft PVC and hard PVC), it is easy to become brittle and difficult to store, so its scope of use is limited. Hard PVC does not contain softener, so it is flexible, easy to form, not brittle, non-toxic and pollution-free, and has a long storage time, so it has great development and application value. The essence of PVC is a kind of vacuum blister film, which is used for the surface packaging of various panels, so it is also called decorative film, adhesive film, and is used in many industries such as building materials, packaging, and medicine. Among them, the building materials industry accounts for the largest utilization rate at 60%, followed by the packaging industry, and there are several other small-scale applications.

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What are the characteristics of PVC rigid board?

PVC sheet has high strength, good temperature resistance and good corrosion resistance. Adding additives can meet the requirements of increasing strength, toughness, hardness, flame retardancy and printing. PVC extruded transparent sheet has the characteristics of flame retardant self-extinguishing, high quality and low price, high transparency, good surface gloss, less crystal points, small water lines, strong impact resistance and easy molding. It is widely used in various tools, toys, Blister, folding box, packaging, etc. in electronics, food, medicine, clothing and other industries. PVC transparent soft board soft curtain is a replacement product of traditional cotton curtain. This product is soft, transparent, insulated, safe, green, environmentally friendly, acid and alkali resistant, no odor, easy to clean, etc. It can keep cold, heat preservation, energy saving, dustproof, windproof, moisturizing, anticorrosive, fireproof, antistatic, and strong. Light, anti-ultraviolet, sound insulation, table mats, daylighting, industrial vibration reduction, safety warnings, floor and walls, surface protection of utensils and paint film protection, can be used for freezing, food, printing, textiles, electronics, instruments, pharmaceuticals, storage, Shopping malls and other places. It has a good effect on the insulation of live working places and the interruption of harmful arcs. The high-speed extruder adopts a slotted barrel (water-cooled forced feeding section) and a barrier type (or reactive) special screw with a special mixing structure to realize the high speed and efficiency of the PVC sheet extrusion process. The coat-hanger die adopts a special double throttling design to make the thickness of the extruded sheet more accurate. The temperature is controlled at ±1°, which can accurately control the plasticizing process and the thickness and flatness of the sheet. The three-roll calender adopts horizontal, vertical or 45-degree inclined type, which can be raised and lowered freely. The independently controlled roller temperature control system can accurately control the temperature of the pressure roller, so that the thickness of the sheet is uniform. The winding table device adopts an advanced torque motor, which can adjust the speed and winding tension at will.

 


Post time: Mar-17-2021