Recycled plastic is the reuse of plastics. After crushing with mechanical blades, the reuse of plastics is completed.
Product introduction
Recycled plastics refer to plastic raw materials obtained by processing waste plastics through physical or chemical methods such as pretreatment, melt granulation, modification, etc. It is the reuse of plastics.
Uses
Plastic has good processing properties and is easy to shape, such as blowing, extruding, pressing, easy to cut, and easy to weld. In production and life, many plastics can be granulated, such as waste food bags, sandals, wires, wire boards, agricultural films, tubes, barrels, basins, packing tapes and various waste plastic products that can be repeatedly molded and processed into plastics. Raw materials are used to make machine parts and components through special processes and formulas; they can be used to make water pipes, agricultural machinery, packaging bags, and cement bags; they can replace some wood products; they can be used to make various plastic bags, barrels, basins, and toys. and other plastic products, daily necessities.
Recycled plastics and granulated plastics have broad prospects, turning waste into treasure. The products (plastic granules) have a wide market, and plastic companies have a large demand. A medium-sized agricultural film factory requires more than 1,000 tons of polyethylene granules annually, and a medium-sized shoe factory needs more than 1,000 tons of polyethylene granules annually. It requires more than 2,000 tons of polyvinyl chloride pellets. Smaller individual private enterprises also need more than 500 tons of pellets annually. Therefore, there is a large gap in plastic pellets and cannot meet the demand of plastic manufacturers. Therefore, the sales are excellent and the benefits are extremely high. good. Waste plastic raw materials come from a wide range of sources. Waste plastics are found wherever there are people. They are easy to purchase and cheap (this is true in various places). A city consumes more than 10 tons of plastic food bags and other plastic products every day. There is also a large amount of waste plastics in rural areas that can be recycled. The pellets don’t have to worry about sales.
Advantages
1. The world’s resources will always be a hot topic for mankind. The slogan of saving resources and protecting the environment has gradually been deeply rooted in the hearts of the people. Plastics will not rot even if they are buried underground for hundreds of years. Therefore, the awakening of recycling recycled materials is also inevitable., so that people can truly achieve environmental protection and energy saving through resource recycling. The biggest advantage of recycled materials is that the price is definitely cheaper than new materials. According to different needs, you only need to process certain attributes to produce corresponding products. This will not cause the loss of resources. Plastics are refined from petroleum. Products made from petroleum resources are limited, so recycling recycled plastics can save petroleum resources.
2. Due to the non-degradable nature of plastic, it has become the number one enemy of mankind and has also led to the tragedies of many animals. For example, monkeys, pelicans, dolphins and other animals in the zoo will mistakenly swallow the No. 1 plastic bottles thrown away by tourists, and eventually die in pain due to indigestion; looking at the beautiful and pure sea, and taking a closer look, it is actually full of plastic bottles. A variety of plastic waste that cannot be accommodated by the ocean. Various types of plastic that cannot be digested have been found in the intestines of many dead seabird samples. Therefore, recycling recycled plastic can prevent a large amount of plastic waste from being thrown around, thereby preventing animals from ingesting it.
Shortcoming
1. When recycling waste plastics, classification is very difficult and economically uneconomical.
2. Plastics have poor heat resistance and are prone to aging.
Performance changes
PVC: The discoloration is obvious after regeneration. It will be light brown after the first regeneration and extrusion, and it will become almost opaque brown after the third regeneration. The specific viscosity remains unchanged after the second regeneration, and will tend to decrease after the second regeneration. Whether it is hard or soft PVC, stabilizers should be added during regeneration. In order to make the remade products glossy, 1%-3% of ABS for blending can be added during regeneration.
PE: After regeneration, the performance of PE decreases and the color turns yellow. After repeated extrusion, the viscosity of high-density polyethylene decreases and the viscosity of low-density polyethylene increases.
PP: When regenerated once, the color is almost unchanged and the melt index increases. When the color becomes worse after two or more regenerations, the melt index still increases. After regeneration, the breaking strength and elongation decreased, but there is no problem in use.
PS: The color turns yellow after regeneration, so regenerated PS generally undergoes color difference. The degree of decline in various properties of recycled materials is proportional to the number of regenerations. The breaking strength does not change significantly when the blending amount is less than 60%. The ultimate viscosity does not change significantly when the blending amount is less than 40%.
ABS: The discoloration is more obvious after regeneration, but there is no significant change in performance when the blending amount does not exceed 20-30%.
Nylon regeneration also has problems of discoloration and performance degradation, so the blending amount should be less than 20%. The regeneration elongation decreases, but the elasticity tends to increase.
Distinguish between good and bad
1. Look at the color
The lighter the color (even colorless and transparent), the wider the application range and the higher the grade. For example, if it is white, it can be adjusted into a variety of other colors, or it can be made back into white products, but the price is also high. Secondly, due to the needs of the product, various ingredients are added to the raw materials.
2. Look at the CaCO3 (stone powder) content
The higher the CaCO3 content, the lower the grade, and the lower the price. From the naked eye, if the product is not bright and dull (except for matt), it will contain more CaCO3, and it will feel heavy to the touch. If it is burned with fire, the burned part will turn red and turn to ash. In addition, we should also pay attention to reinforced (referring to glass fiber) products. The only available reinforced products are PA, PBT, PP, etc., and the prices are not high. There are also several alloy materials. Only ABS+PC is sold in China, and the others are not available. Then judge whether the mixed materials can be reused based on the specific gravity (density) of the raw materials. The most problematic ones are the mixing of ABS and PS, the mixing of PC and PMMA, the mixing of PVC flakes (bottle materials) and PEl, and the mixing of flakes., half and half of PE and PP are mixed with each other. After these materials are mixed with each other, they have similar densities and are difficult to use.
3. Check whether the recycled plastic material is pure or not
The purer the material, the higher the grade; the impure material, the lower grade, and some mixed materials are not even wanted.
4. Differences from waste plastics
Waste plastic is directly crushed into powder or granular form, and the material can still be distinguished, such as injection molding, wire drawing, film, etc. Recycled materials have been recycled countless times and cannot be accurately identified. They can only be classified into grades according to the number of cycles. Starting with the smallest ones, they are divided into special grade, first grade, and second grade.
Market price assessment
Price assessment of recycled plastics
1. Color and performance of recycled plastics
Generally speaking, the lighter the color of the recycled plastic, the more desirable the price. The closer the performance is to new materials, the more ideal the price is. The better the performance indicators that focus on, the more ideal it is.
2. Purity of recycled plastics
The higher the purity of the recycled plastic, the more ideal it is, except for the modified material, because the modified material mainly depends on the performance indicators; the compatibility of the components in the recycled material can also be included in this point, the better the compatibility, the higher the price.
3. Appearance of recycled plastic
First, look at the granulation shape. The better the granulation shape, the higher the price will basically be; secondly, check whether it is foamed, layered, whether the hardness meets the requirements, whether the color is uniform, whether the gloss is good, etc.
4. Application of recycled plastics
The use, processing characteristics, wide range of applications, and other special requirements of recycled plastics will all affect the valuation of recycled plastics.
China standards
In 2021, China issued 3 recommended standards, which will be implemented from December 1, 2021:
GB/T 40006.1-2021 Plastic recycled plastics Part 1: General principles;
GB/T 40006.2-2021 Plastic recycled plastics Part 2: Polyethylene (PE) materials;
GB/T 40006.3-2021 Plastic recycled plastics Part 3: Polypropylene (PP) materials.
