In many areas of China“gelatin、Bone glue、Leather glue”It is crushed into particles and powders by a certain processFine chemical products。stayHebeiShandong area usually refers to gelatin products, which can be processed into 5-120 meshes.The finer the rubber powder, the longer it takes to process, and the faster it dissolves in use.The rubber powder is white, light yellow to yellow or amber in appearance, translucent, without unpleasant smell and visible impurities.Its molecular weight is 1-100000, containing 18 kinds of amino acids, water and inorganic salt content is below 16%, and protein content is above 82%. It is an ideal protein source.Products are widely used inPhotosensitive material, medicine, furniture, packaging, paper making, textile, printing and dyeing, printing, ceramics, daily chemicals, food, paint, metallurgy and other industries, and in which mainly play the role of thickening, stability, cohesion, blending, polishing, sizing, bonding, water fixation and so on.According to incomplete statistics, rubber powder is used in more than 30 industries and more than 1000 products.Of course, different industries and products have different requirements for the quality grade of rubber powder.
Basic classification
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According to different methods, it can be classified into normal temperature rubber powder, frozen rubber powderPutty glue powderInstant rubber powder, superfine rubber powder and fine rubber powder;According to the source of raw materials, it can be divided into truck tire rubber powder, passenger car tire rubber powder and shoe rubber powder, and it can be divided into activated rubber powder and inactive rubber powder according to whether it is activated or not;It can be divided into ultra-fine rubber powder and general rubber powder according to particle size[1]。
Production method
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Preprocessing of waste rubber
wasteRubber productsIn general, there are fibers, metals and other non rubbersSkeleton materialIn addition, there are many kinds of rubber products, so the waste rubber must be processed in advance before crushing, including sorting, removal, cutting, cleaning and other processing.The waste rubber shall also be inspected and classified, and the waste rubber and its products of different categories and sources shall be classified according to requirements. The best way is to adopt the recycling management cycle method, and treat the waste rubber purposefully according to the source of waste rubber.For products with large volume such as waste tires, the bead should be removed, and tread separators are also used to separate the tread from the carcass.The sole of rubber shoes is mainly recycled, and the valve of inner tube is removed.
After sorting and removing non rubber components, the waste rubber cannot be directly crushed due to its different length and thickness. The waste rubber must be cut.The tire is generally cut into 25mm × 25mm rubber blocks with the whole tire cutter abroad.The large rubber block will be returned to the cutting machine for cutting again.
The waste rubber, especially the tire and rubber shoes products, should be cleaned by the rotary drum washing machine first to ensure the quality of rubber powder because of the long-term contact with the ground and the inclusion of many impurities such as silt.
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Normal temperature grinding method
It mainly uses shearing to cut and crush waste rubber, which is generally divided into two processes: coarse crushing and fine crushing.In the normal temperature grinding, the normal temperature rolling method and the tire continuous grinding method are most commonly used.The normal temperature grinding method is the main method of rubber powder production in the world, with good technical and economic efficiency.
Low temperature grinding method
It can be divided into liquid nitrogen low-temperature grinding method and air expansion refrigeration grinding method according to the different freezing media used.It uses low temperature to make rubber reachGlass transition temperatureBecome brittle, and then crush it with mechanical force.The liquid nitrogen method has large consumption and high cost;The air expansion refrigeration pulverization method uses air as the refrigeration medium, which is energy-saving, water-saving, high efficiency and low cost compared with the liquid nitrogen method.
In industrial developed countries, there are subsidies for waste rubber treatment, so liquid nitrogen method and air expansion refrigeration crushing method can be used.Developing countries and countries without subsidies should adopt the normal temperature method to produce rubber powder to adapt to the market and achieve better economic benefits.
Wet method or solution method
Select the appropriate liquid medium to make the rubber brittle, and then grind it on the colloid mill.According to the liquid medium used, it can be divided into water suspension grinding and solvent expansion grinding.The surface treated rubber powder prepared by water suspension grinding is dried after grinding in water;For solvent crushing, organic solvent is used to swell the rubber powder and grind it, then the solvent is removed and dried to obtain rubber powder.Wet method or solution method is used to produce rubber powder with fine particle size and good application performance, but its production requirements are high, requiring a large number of liquid media.
production
Rubber powder is mainly produced by freezing crushing method and normal temperature crushing method.
Freeze crushing production
There are two kinds of freeze grinding technology: one is low-temperature freeze grinding technology.The other is the comminution process at low temperature and normal temperature.The former uses liquid nitrogen as the refrigeration medium to make waste rubber used after deep coolingHammer millOr roll mill for low-temperature crushing.The production line of fine rubber powder adopts the latter method for production.The liquid nitrogen cryogenic technology is used to process waste tires into fine rubber powder of more than 80 meshes. The temperature, speed and overload in the production process are all controlled by closed-loop interlocking microcomputer, which has no pollution to the environment.The whole production process of the production line adopts compressed air powered feeders and closed pipes for transportation. The whole line is closed except for waste tires and products that are in contact with air when they are put into use and packaged.In addition, since the freezing method is used for production, there is no high temperature odor, so there is no secondary pollution.Through the heat exchange process between the fine rubber powder and the coarse powder, the purpose of making full use of energy, reducing energy consumption and reducing product cost is achieved.
Normal temperature crushing production
Normal temperature grinding method.The waste rubber is crushed at room temperature after pre processing, generally divided into coarse crushing and fine crushing.In China's reclaimed rubber factories, two crushing methods are often used. One is that coarse crushing and fine crushing are completed on the same equipment;The other is that coarse crushing and fine crushing are completed on two different equipment.The former is suitable for production in small factories.
The way that coarse crushing and fine crushing are carried out at the same time: one of the two rollers for this operation has a groove on the surface and the other has no groove, that is, the grooving roller machine.First, the washed rubber block is sent to the two rollers through the conveyor belt for breaking the rubber, and then the broken rubber block and rubber powder fall into the reciprocating screen at the bottom of the equipment for screening, and those that meet the particle size requirements fall from the screen, and then enter the warehouse through the conveyor;The rubber blocks that do not meet the requirements shall be turned over and then enter the grooving roller for further crushing.
The way of coarse crushing and fine crushing is carried out on two sets of equipment: the coarse crushing is carried out on the grooved roller machine with grooves on the surface of both rollers, and the size of the rubber block after coarse crushing is generally 6-8mm.Then it enters the smooth roll fine crusher for fine crushing, and its particle size is generally 0.8-1.0mm (26-32 meshes).The crushing equipment of rubber powder plant is different from the traditional crushing equipment of reclaimed rubber. It is a special waste rubber crusher, intermediate crusher and fine crusher.
application
Generally, rubber powder is mainly mixed in low-grade products in a large amount, and can also be used in tread in a small amount to reduce the dynamic heat generation life of tires. For example, 100 or more pieces of rubber powder are mixed in the midsole of shoes.It is used in building materials, such as laying sports ground, laying track bed foundation, shock absorption, noise reduction and other occasions.Add rubber powder under medium and high temperature of asphalt products and mix it evenly for pavement and roofwaterproofThe layer effect is very good. Sometimes a small amount of ultra-fine rubber powder can be used in high-end products. Because the ultra-fine rubber powder can improve the tear, fatigue and other properties, it is also specially required to be mixed in some products. For example, adding 10 parts of rubber powder with a fineness of more than 100 meshes in the tread rubber can improve the driving distance of the wheel tire.The performance of surface activated rubber powder will be further improved than that of non activated rubber powder, and its application will be further expanded.
Production of fine rubber powder
Production of fine rubber powder I. Project overview: rubber is an important material related to the national economy and the people's livelihood, and China's annual demand has risen significantly.Using waste rubber to make rubber granules, which is the raw material for producing rubber products, not only saves resources, but also reduces costs, so it is called the sunrise industry.Waste automobile tires can be seen everywhere in the Far East of Russia. The value of recycling is very high. The benefits of investing in this project must be considerable.In Suifenhe City, we can make full use of a large number of waste tires in Russia and waste rubber products in China to build a rubber powder production line.2、 Project content: Revitalize stock assets and purchase processing equipment.3、 Investment estimation: if the annual output is 1000 tons, the investment will be 3 million yuan.[2]
Performance characteristics
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In terms of powder engineering, rubber powder is a kind of powder granular material, so for rubber powder, particle size (specific surface area), surface morphology, group and its own composition will have an important impact on its use performance.
The finer the rubber powder, the better its performance.The finer the rubber powder is, the closer the tensile strength, elongation and wear of the vulcanizate are to those without rubber powder.The fatigue resistance, crack growth resistance and other properties are higher than those without rubber powder. The finer the rubber powder, the greater the increase.
Development status
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In 1930, the first patent for powdered rubber was filed in the United States.In 1956, BF. Goodrich first producedPowdered nitrile rubber。Since then, many foreign scholars have actively studied the new product of powdered rubber and developed powderbutadiene styrene rubber。Dunlop developed the powderEPDMAnd powdered silicone rubber;American Esso Company has developed the powderbutyl rubber ；Harrison has established powder in MalaysiaNatural rubberManufacturer.However, in the following 20 years, the development of powdered rubber stagnated due to various reasons[3]。
Until the 1980s, the production and application of powdered rubber began to recover.At the same time, the special processing equipment for powdered rubber has made rapid development.
At the end of 1990s, due to the rapid development of polymer modification industry, the expansion of demand for tire processing industry, the progress of production and processing technology of powdered rubber, and the requirements of global environmental protection, the technology of preparing rubber powder from waste rubber has also developed rapidly.
The research on powdered rubber in China started from the research institute of Lanzhou Chemical Industry Company Synthetic Rubber Factory in the 1970s.At that time, due to the low level of technology in China, and the fact that researchers did not master the isolation technology, which was the key to the preparation of powdered rubber by spray drying, the research work stopped halfway.In 1987, with the support of the state, the institute restarted the research and development of powdered rubber and made great progress.In the 1990s,South China University of TechnologyPSBR powder rubber was successfully prepared by polymer coating coacervation method.Since then, the research work on rubber powder has been carried out in China.[4]
Plastic powder
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HJS-09 plastic powder is a kind ofPolymerThe modified transformation material is a cold water soluble powder with bright and transparent film and high hardness. The solution is highly viscous, high-strength and transparent, which can be used for bonding of various materials, coatings, various putty powdersThermal insulation mortarAnd other polymer materials.
