Comprehensive interpretation of the hottest low ca

2022-07-26
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Comprehensive interpretation of low carbon plastics

what is low carbon plastics

low carbon plastics refer to plastic materials that emit low carbon dioxide during the whole life process of synthesis, processing, storage, operation, use and waste

in the life cycle of plastic products, carbon dioxide emissions mainly come from the two processes of synthesis and processing energy consumption, incineration and degradation, and a small amount of decomposition in processing can be ignored. The carbon dioxide released from the energy consumption of synthesis and processing accounts for 80%. The solution depends on energy-saving technology and the use of recycled plastics; The carbon dioxide released by incineration and degradation accounts for 20%. The solution depends on emission reduction. Specifically, low-carbon emission plastics, such as biological plastics and inorganic filled plastics, are selected

low carbon energy saving technology

select energy-saving equipment

energy saving equipment includes all electric injection molding machine, servo injection molding machine, blade type processing equipment and continuous internal mixing equipment

1. The full electric injection molding machine

is powered by four servo motors and two asynchronous motors, which respectively drive the mechanisms such as mold locking, mold opening, mold adjustment, ejection, injection, glue melting and injection device to complete the series of actions required for plastic product injection processing

advantages: (1) the energy-saving effect is the best, which is more than 50% energy-saving compared with the same type of quantitative pump injection molding machine. (2) The injection speed is fast, which can effectively improve the processing efficiency. (3) The injection quantity is controlled accurately, which is the preferred equipment for precision injection. (4) The transmission is firm and reliable. Because the special heavy-duty ball screw is used to drive the template, injection screw, thimble, etc. for reciprocating motion, the loss of converting electrical energy into mechanical energy is small. (5) It can produce products with complex shapes. Each motor can work synchronously, which can meet the linkage requirements of some plastic products with complex structure when closing and opening the mold. The energy-saving principle of the electric injection molding machine is not affected by the injection process conditions, which cannot be achieved by other energy-saving models. It can save energy consumption to the greatest extent

the disadvantage of the fully electric injection molding machine is that its structure is complex, it can only be a small model (generally no more than 500t), and its price is expensive (times that of the ordinary machine of the same company). List of low carbon plastics

2. Servo hydraulic injection molding machine

is driven by servo motor and matched with high-pressure internal gear pump for hydraulic transmission. The working signal is transmitted to the servo motor through the servo controller, and the flow and pressure of each working procedure are adjusted by the change of the speed of the servo motor

advantages: it combines the advantages of servo and hydraulic transmission models. The models can be as large as ordinary machines (at present, Shenzhen Lijin group has produced 3200t models). The development history of fatigue testing machines that can meet the model can be traced back to the early 19th century. After the industrial revolution, with the development of steam locomotives and motor vehicles and the extensive use of mechanical equipment, the destruction of moving parts often occurs, This is a typical metal fatigue phenomenon, and people did not pay attention to this at that time, let alone the concept of fatigue experiment with core pulling requirements. The control system of this model uses pressure closed-loop plus servo. The information feedback of each action is accurate, the response speed of hydraulic control elements is fast, and the energy-saving effect is obvious. It is 30% more energy-saving than the quantitative pump injection molding machine (second only to the all electric injection molding machine). Because the internal gear pump is used, the noise is lower than that of ordinary machine

disadvantages: cleanliness and pressure loss in hydraulic transmission are no different from those of ordinary models. The price is high, 3-5 times higher than that of ordinary models

transformation of original equipment

transformation of original equipment, including servo motor, variable displacement pump, frequency converter and other technologies in motor, electromagnetic heating, far-infrared heating and other technologies in heating

1. Frequency conversion energy-saving technology

according to the requirements of injection process conditions on pressure and flow, the collected signals are changed by the frequency converter to meet the energy-saving requirements

advantages: the reconstruction project has short period and small investment

disadvantages: its energy-saving effect is affected by the injection molding process conditions

the frequency conversion energy-saving technology not only has a good effect on the quantitative pump injection molding machine, but also can play a good role in other models. The frequency conversion energy-saving transformation technology has changed from the used v/f frequency converter to the vector frequency converter, and the energy-saving effect has been significantly improved

2. Electromagnetic heating technology

electromagnetic heating technology is to heat the metal barrel itself through the principle of electromagnetic induction, so as to heat the plastic raw materials in the barrel. This heating technology is one-way heating to the material, with electromagnetic heating efficiency up to 95%, and the surface temperature of the barrel is reduced from hundreds of degrees to tens of degrees. After scientific tests, the electromagnetic radiation generated during heating is very small, several times smaller than that

advantages: the thermal efficiency of the melt is high, and the heat is concentrated inside the barrel. The utility model avoids the waste caused by the heat emission of the resistance wire heating ring to the surrounding, and purifies the workshop environment. The electromagnetic coil has a long service life and is not as easy to be damaged as the resistance wire heating ring. The period of technical transformation project is short, and the investment recovery period is not long (nine months). The energy-saving effect of the barrel part is 40% less than that before the transformation

disadvantages: it is insensitive in the control of metering section. When the melt reaches the process temperature, the melt gathered in the metering section does not need to be heated up. As long as it stays a little longer, the plastic will degrade, which is extremely detrimental to the quality of plastic products. The temperature rise is relatively fast, but it will be relatively slow if it needs to be cooled

3. Far infrared heating technology

the heating element of this technology adopts a new type of nano plate. After the surface is specially treated with special far-infrared materials, it can produce infrared rays with specific wavelengths. The thermal efficiency and conduction efficiency are more than 95%, and the heat transfer efficiency is much higher than that of the traditional heating ring

this far-infrared heating technology not only has fast temperature rise, but also has good heat preservation effect, little impact on ambient temperature, stable product performance, high power saving rate, advanced technology and simple installation. It can directly replace the original heating ring without any suspicion of electromagnetic radiation

recycled plastics

recycled plastics have completed a life cycle of plastic products, thus eliminating the link of synthetic energy consumption and having a high emission reduction effect. But not all waste plastics can be regenerated. Thermosetting and over crosslinked waste plastics cannot be regenerated. Mixed non separable plastics and multi-layer composite non separable plastics are difficult to regenerate due to poor compatibility

1. From the perspective of raw materials, the feasibility of using recycled plastics is as follows:

(1) purity of recycled plastics: pure recycled plastics are easy to use; Mixed recycled plastics - washing materials, filling materials, reinforcing materials, alloy materials and barrier fuels are difficult to use; Composite recycled plastic products are difficult to use; A small amount of printed recycled plastic is used, which affects the color and heat sealing strength

(2) color of recycled plastics: transparent recycled plastics can be used; White and light recycled plastics can be used

(3) whether recycled materials are crosslinked: thermosetting plastics cannot be used; Cross linked plastics can not be used, such as cross-linked polyethylene cable materials, foaming materials, etc

2. From the perspective of products, the feasibility of using recycled plastics is as follows: transparent plastic products cannot use recycled plastics; A small amount of recycled plastic is used for white or light colored plastic products; Natural environment and operation methods for the installation of steel bar zigzag testing machine for medical earthquake and food; what plastic products cannot use recycled plastics; Recycled plastics shall not be used for plastic products with high performance requirements

there are many regeneration methods for waste plastics: pure regeneration, blending regeneration, filling regeneration, reinforcement regeneration and foaming regeneration

low carbon emission plastics

according to the different raw materials of synthetic plastics, we can divide plastics into three categories: biological plastics (biomass), petrochemical plastics (oil, coal or natural gas) and inorganic plastics (limestone, salt, calcium carbonate and talc powder)

bioplastics

bioplastics is a kind of plastics made of biomass materials. Biomass materials refer to natural polymer materials grown in nature, mainly including starch, cellulose, protein, lignin and chitosan

compared with petrochemical plastics, bioplastics have the following advantages: first, low carbon emission - because biomass can absorb a large amount of carbon dioxide gas in the growth process, it has a carbon neutralization effect; It only has carbon dioxide emissions equivalent to 20% of petroleum plastics, so it is also called low-carbon plastics. Second, recycling - biomass material is the only abundant resource on the earth that has not been well utilized

biomass materials cannot be directly used in plastics because they are not thermoplastic. They can only be used in plastics after appropriate treatment. At present, the methods that have been successfully developed to manufacture plastics from biomass materials include: self modification of biomass materials, blending modification with plastics, and biological fermentation synthesis of plastics

there are many kinds of bioplastics, which can be divided into the following categories according to different classification methods

it is classified according to the biomass content in bioplastics. If all bioplastics come from biomass materials, it is called all bioplastics, otherwise it is called part of bioplastics

according to different manufacturing methods of bioplastics, they can be divided into natural and synthetic categories

according to whether bioplastics are degradable or not, they can be divided into two categories: degradable and non degradable. Classification of degradable and non degradable bioplastics

classification of natural and synthetic bioplastics

examples of bioplastics developed at present:

1. Some bioplastics

starch plastics: bioplastics modified by different methods with natural biomaterials such as starch or cellulose, and its representative varieties are PSM, etc

ptt plastic: the engineering plastic PTT developed by DuPont company of the United States, in which the alcohol synthetic monomer comes from biomass materials, making the biomass content of PTT reach about 40%

pa410: DSM engineering plastics company of the Netherlands developed pa410, in which the monomer sebacic acid comes from castor oil, accounting for 60% of pa410. This kind of plastic can achieve 100% carbon neutralization, that is, the carbon dioxide produced in pa410 production can be balanced with the carbon dioxide absorbed during the growth of castor oil

plastic wood products: the wood powder and straw powder of biomass materials are blended with petroleum based plastics to make plastic wood products, which can realize the effective utilization of a large number of biological materials. At present, the leading products of wood plastics in the market are PE or PVC, which has a broad market prospect

2. All biological plastics

protein plastics: for example, soybean fiber made in China has been woven into clothing fabrics; Another example is that the University of waikat in New Zealand has made protein plastics from animal hooves and feathers. At present, it has made a variety of plastic products

1958, Shanghai Celluloid company used castor oil as raw material to synthesize the only original nylon variety PA1010 in China. So far, it has been exclusively produced in China

Braskem, a Brazilian chemical giant, is developing a kind of bio polyethylene, which is a renewable and environment-friendly polyethylene plastic made from sugarcane ethanol. Compared with the traditional petroleum raw material polyethylene, the carbon dioxide emission in the production process of new plastics is less. The company plans to start the commercial production of this bioplastic in 2011, with an annual production capacity of 200000 tons

pa10t developed by Guangdong Jinfa company has better performance than PA9T

Cereplast Inc, a bioplastic manufacturer in California, USA, announced that it would launch a series of bioplastic resins based on all natural algae by the end of 2010, which can be mixed with polypropylene or other standard resins, suitable for injection molded parts or thermoformed parts, and can

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