Usually, the natural rubber we refer to refers to the natural latex collected from Brazilian rubber trees, which is made into elastic solids through curing, drying and other processing procedures. Natural rubber is a kind of natural polymer compound with cis-1, 4- polyisoprene as the main component. Its rubber hydrocarbon (cis-1, 4- polyisoprene) content is above 90%, and it also contains a small amount of protein, fatty acids, sugar and ash.
Chinese name: natural rubber mbth: NR(Natural Rubber) Main ingredients: cis-1, Molecular formula of 4- polyisoprene: (C5H8)n Classification: Characteristics of solid natural rubber and concentrated latex: resilience, insulation, water repellency, plastic development history, strategic position, characteristic distribution, composition, physical properties, natural attributes, microstructure of natural rubber, variety classification, main uses, performance, related information, transportation and storage, production country, development status, and so on. Natural rubber 1736 was discovered in Columbus in 492, and it was not until 1736 that France first reported the origin of rubber, the method of collecting latex and the local utilization of rubber in South America, so that Europeans began to understand natural rubber and further studied its utilization value. After 1839, 100 years passed. Until 1839, American C. Goodyear discovered that sulfur and basic lead carbonate were added to rubber. After being heated or exposed to the sun, rubber products are no longer as easy to soften and stick as before, but maintain good elasticity, thus inventing rubber vulcanization. 1888, an Englishman named J.B. Dunlop invented pneumatic tires, which promoted the rapid development of automobile tire industry, resulting in a sharp increase in rubber consumption. From 65438 to 0876, H.Wickham, an Englishman, collected rubber seeds from the mouth of Masson River in Brazil, transported them back to the Royal Botanical Garden and planted them in Ceylon (Sri Lanka), Indonesia and Singapore, all of which were successful. This is the beginning of the settlement of Brazilian rubber trees in the Far East. Since then, the planting of rubber industry has developed very rapidly. 1997 The world output of natural rubber has reached 6.247 million tons. After the founding of New China, the scientific and technological workers of China Agricultural Reclamation broke the conclusion that the north of 15 was a "forbidden area" for Brazilian rubber tree planting in the past century, and successfully planted Brazilian rubber trees in the vast area from north latitude18 to north latitude 24, and achieved high yield. 1996 natural rubber production has reached 420,000 tons, making it the fifth largest natural rubber producer in the world. Strategic Position In 2007, the General Office of the State Council issued the Opinions on Promoting the Development of China's Natural Rubber Industry (Guo Ban Fa [2007] 10), which further clarified the strategic position of "Natural Rubber is an important strategic material and industrial raw material", affirmed the great contribution made by China's natural rubber industry, pointed out the problems and challenges existing in the current development of China's natural rubber industry, and put forward the guiding ideology for the future development of China's natural rubber industry. The Opinions clearly state that by 20 15, the annual production capacity of natural rubber in China will reach more than 800,000 tons, and the overseas production and processing capacity will reach more than 600,000 tons. The Opinions clearly defined the direction for the rapid and healthy development of China's natural rubber industry, created a good environment and opened up a broad working space. This is an epoch-making programmatic document guiding the development of China's natural rubber industry in the new period, which has great practical significance and far-reaching historical significance. Characteristic distribution Rubber tree originated in the west of Marayo, Amazon basin, Brazil, and has been distributed to more than 40 countries and regions in Asia, Africa, Oceania and Latin America. Countries with large planting areas include: Indonesia, Thailand, Malaysia, China, India, Viet Nam, Nigeria, Brazil, Sri Lanka and Liberia. Rubber planting areas in China are mainly distributed in Hainan, Guangdong, Guangxi, Fujian and Yunnan, and can also be planted in Taiwan Province Province, among which Hainan is the main rubber planting area. An evergreen tree with milky juice. The root system is straight, the compound leaves are trifoliate, and the leather is entire. Flowers unisexual, monoecious, panicle. The fruit is a capsule with oval seeds. Rubber tree in Brazil has great variability and adaptability. The annual average temperature is 26 ~ 27℃, and there is no absolute minimum temperature below15℃. The annual rainfall is more than 2500mm, which is evenly distributed; The annual average relative humidity is above 80%; The soil depth is above 1m, the surface layer is 20 ~ 30cm, the organic matter content is above 3%, and the soil pH value is 5 ~ 6. The soil quality is loam, and the groundwater level is more than 1.5 ~ 2m. The altitude is generally below 300m, and it is planted in areas where there is no strong wind. Natural rubber is extracted from the juice of plants. Although there are more than 2,000 plants in the world that can produce natural rubber, Brazil rubber tree is widely planted. The collected natural rubber is mainly composed of cis-polyisoprene, which has the characteristics of high elasticity, high tensile strength, good tear resistance and wear resistance, and easy adhesion with other materials, and is widely used in the production of rubber products such as tires and adhesive tapes. Hevea brasiliensis likes high temperature, high humidity, calm wind and fertile soil, and is mainly planted in low latitudes such as Southeast Asia. Limited by natural conditions, only Hainan, Guangdong, Yunnan and other places in China can be planted, with an available area of about 6.5438+0.5 million mu. About140,000 mu has been planted, with an annual output of about 600,000 tons. Composition of natural rubber There are about 2,000 different plants in the world that can produce polymers similar to natural rubber, and different kinds of rubber are obtained from 500 plants, but the truly practical one is the Brazilian rubber tree with three leaves. When the surface of the rubber tree is cut, the milk duct in the bark is cut off and the milk flows out of the tree. The latex collected from rubber trees is diluted, acid cured, washed, tabletted, dried and packaged to obtain natural rubber on the market. According to the different methods of making rubber, natural rubber can be made into cigarettes, air-dried films, crepes, technical dry rubber and concentrated latex. Natural rubber Standard rubber or granular rubber is a new type of natural rubber developed in 1960s. In the past, general traditional products, such as cigarette flakes, crepe flakes and air-dried flakes, hindered the development of natural rubber in classification methods and manufacturing methods. Therefore, Malaysia began to implement the standard rubber plan in 1965, and developed the production of granular rubber based on the classification of physical and chemical properties of raw rubber. Standard rubber refers to rubber classified according to mechanical impurities, plastic retention rate, initial plastic value, nitrogen content, volatile matter, ash content, color index and other physical and chemical performance indicators. The standard rubber packaging is also relatively advanced, generally packed with polyethylene film and clearly marked. The bag is light in weight and easy to move. The packing weight in Malaysia is 33.3kg, and that in China is 40kg. The classification of standard rubber is more scientific, so this classification method was quickly accepted by major natural rubber producing countries and international standardization organizations, and the classification standards of standard rubber were formulated one after another. These standards are roughly the same, but they are not completely consistent. For example, ISO2000 stipulates five grades, while our national standard GB 808 1-87 stipulates four grades. Physical properties are generally flaky solids, with relative density of 0.94, refractive index 1.522, elastic modulus of 2 ~ 4 MPa, 130 ~ 140℃ softening, 150 ~ 160℃ sticky and soft, 200℃. High elasticity at room temperature, slightly plasticity, crystallization and hardening at low temperature. Good alkali resistance, but not strong acid resistance. Insoluble in water, lower ketones and alcohols, but soluble in nonpolar solvents such as chloroform and carbon tetrachloride. Natural Properties The natural rubber we usually refer to refers to the natural latex collected from Brazilian rubber trees, which is made into an elastic solid through solidification, drying and other processing procedures. Natural rubber is a natural polymer compound with cis-1, 4- polyisoprene as the main component, and its molecular formula is (c5h8) n. Its rubber hydrocarbon (cis-1, 4- polyisoprene) content is above 90%, and it also contains a small amount of protein, fatty acids, sugar and ash. Physical properties of natural rubber. Natural rubber has high elasticity at room temperature, slightly plasticity, very good mechanical strength, low hysteresis loss and low calorific value during repeated deformation, so its bending flexibility is also good, and because it is nonpolar rubber, its electrical insulation performance is good. Chemical characteristics of natural rubber. Because of unsaturated double bonds, natural rubber is a substance with strong chemical reaction ability. Light, heat, ozone, radiation, bending deformation, copper, manganese and other metals can promote the aging of natural rubber. Aging resistance is the fatal weakness of natural rubber. However, natural rubber with antioxidants can still be used as usual after being exposed to the sun for two months. Medium resistance of natural rubber. Natural rubber has good alkali resistance, but it is not resistant to strong acid. Because natural rubber is nonpolar rubber, it can only resist some polar solvents, but it will swell in nonpolar solvents, so its oil resistance and solvent resistance are very poor. Generally speaking, hydrocarbons, halogenated hydrocarbons, carbon disulfide, ethers, higher ketones and higher fatty acids can dissolve natural rubber, but their solubility is affected by the degree of plasticization, while lower ketones, lower esters and alcohols are non-solvents of natural rubber. Microstructure of natural rubber The structure of natural rubber is mainly macromolecular chain structure, molecular weight and its distribution and aggregation structure. The structural unit of macromolecular chain of natural rubber is isoprene, and the macromolecular chain is mainly composed of polyisoprene, with rubber content accounting for more than 97%. There are aldehyde groups on the molecular chain, and there is one on average on each macromolecular chain. It is the condensation or reaction between aldehyde group and protein decomposition product that leads to branching and crosslinking, which increases the viscosity of rubber during storage. It is speculated that the macromolecular end of natural rubber is generally dimethylallyl, and the other end is pyrophosphate group, and there are few end groups, aldehyde groups and polymeric elements in the molecular chain. As far as the molecular weight and its distribution of natural rubber are concerned, its molecular weight range is very wide. According to foreign reports, most of them have molecular weights around 30,000, and the strength of raw natural rubber, rubber compound and vulcanized rubber is relatively high, and the strength of general natural rubber can reach 3 MPa. The main reason for the high mechanical strength of natural rubber is that it is a self-reinforced rubber series. During stretching, the macromolecular chains will be oriented along the stress direction to form crystals, and the grains will strengthen the amorphous macromolecules. The reason why the strength is high and does not swell is the close agglutination of tiny particles in its internal structure. Classification of natural rubber varieties Natural rubber can be divided into solid natural rubber (film and particle rubber) and concentrated latex according to its morphology. In daily use, solid natural rubber accounts for the vast majority. According to the different manufacturing processes and shapes, films can be divided into cigarette glue, air-dried film, white wrinkled film and brown wrinkled film. Tobacco flake adhesive is the most representative variety of natural rubber, and it has always been a kind of adhesive with large dosage and wide application. Tobacco flake adhesive is generally classified according to appearance, which is divided into six grades: super grade, first grade, second grade, third grade, fourth grade and fifth grade. * * *, those that fail to reach Grade 5 are classified as external glue. Granular rubber (that is, standard rubber) is classified according to internationally unified physical and chemical properties and indicators, including seven items: impurity content, initial plastic value, plastic retention rate, nitrogen content, volatile content, ash content and color index. Among them, the impurity content is the leading index, which is divided into five grades: 5L, 5, 10, 20 and 50. The contract delivery grades of natural rubber in Shanghai Futures Exchange, China's futures trading market, are domestic first-class standard rubber SCR5 and imported tobacco flake rubber RSS3, among which domestic first-class standard rubber SCR5 is also commonly known as No.5 standard rubber, and all quality indexes of Natural Rubber GB/T 808 1 ~ 1999 issued and implemented by the State Bureau of Technical Supervision are implemented. Imported cigarette rubber RSS3 implements the International Standard for Grade Quality and Packaging of Natural Rubber (Green Paper) determined by the International Rubber Quality and Packaging Conference (version 1979). Main uses Natural rubber has the above-mentioned series of physical and chemical characteristics, especially its excellent resilience, insulation, water repellency and plasticity. After proper treatment, it also has valuable properties such as oil resistance, acid resistance, alkali resistance, heat resistance, cold resistance, pressure resistance and wear resistance, so it is widely used. For example, rain boots, warm water bags and elastic bands used in daily life; Surgical gloves, blood vessels and condoms used in the medical and health industry; All kinds of tires for transportation; Industrial conveyor belts, conveyor belts and acid alkali resistant gloves; Irrigation and drainage hoses and ammonia bags for agriculture; Sounding balloons for meteorological measurement; Sealed shockproof equipment for scientific experiments; Aircraft, tanks, cannons and gas masks for national defense; Even high-tech products such as rockets, artificial earth satellites and spaceships are inseparable from natural rubber. Modern scientific research on properties proves that ordinary natural rubber is polymerized from isoprene. (1) Chemical properties of natural rubber Natural rubber is unsaturated rubber, which easily reacts with vulcanizing agent (structural reaction), oxidative cracking of bromine with oxygen and ozone, chlorination and chemical reaction with halogen, and chemical reaction with catalyst and acid. However, because natural rubber is a polymer compound, it has the reaction characteristics of olefinic organic compounds, such as slow reaction speed, incomplete and uneven reaction, and coexistence of various chemical reactions (such as oxidative cracking reaction and structured reaction). Among all kinds of chemical reactions of natural rubber, the most important ones are oxidative cracking reaction and structural reaction. The former is the theoretical basis of raw rubber plasticizing, and it is also the reason for the aging of folic acid gum. The latter is the theoretical basis of vulcanization of raw rubber. Chlorination, cyclization and hydrogenation of natural rubber can be used to modify natural rubber. (2) Natural rubber has excellent comprehensive physical and mechanical properties. Natural rubber has good elasticity at room temperature. This is because the molecular chain of natural rubber is amorphous at room temperature and has good flexibility. Its density is 0.9 13g/cm, its elastic modulus is 2-4MPa, which is about one third of that of steel, and its elongation is 300 times that of steel, with the maximum of 1000%. In the range of 0- 100 degrees, the resilience of natural rubber can reach more than 50%-85%. (3) Thermal aging natural rubber is a high elastomer at room temperature, and its glass transition temperature is -72 degrees. After heating, it softens slowly, and 130- 140 degrees begins to flow, and it begins to decompose around 200 degrees, and it decomposes violently at 270 degrees. (4) Medium-resistant medium refers to oil, liquid chemicals, etc. Natural rubber is resistant to cyclohexane, gasoline, benzene and other media, but insoluble in polar acetone and ethanol. , insoluble in water, resistant to 10% hydrofluoric acid, 20% hydrochloric acid, 30% sulfuric acid, 50% sodium hydroxide, etc. Potassium permanganate, potassium dichromate, etc., which are not resistant to strong acid and strong oxidation. (5) Good processability Natural rubber is easy to plasticate, mix, calender, extrude and shape. Because of its high relative molecular weight, wide distribution of equivalent molecular weight and easy breakage of molecular chain, there are a certain number of gel molecules in raw rubber. Transportation and storage of related materials Ships and cabins loaded with rubber should be clean and dry, with smooth pipeline system and sewage ditch and tight hatch cover. When loading, the rubber should be separated from the metal part in the cabin by padding, which should be clean, dry, complete and undamaged. China, Viet Nam, Malaysia, Thailand, Indonesia. Since the first half of 20 12, the main economic indicators of domestic rubber industry have maintained a small growth, and the output growth of main rubber products has shown a continuous good trend. Industrial added value dropped slightly from last month, and industrial benefits continued to maintain a good momentum. The data shows that since 20 12, the industrial output value of china rubber products industry has increased by 6.47% year-on-year, and the comprehensive tire output has increased by 2.59% year-on-year. Among them, the radial tire output has increased by 3. 13%, the all-steel radial tire output has increased by 6.55% year-on-year, and the radial rate has reached 87.23%, up by 0.46 percentage points year-on-year. The delivery value of exported tires increased by 1 1.29% year-on-year, and the export rate (value) was 34.23%, an increase of 1.48 percentage points over the previous year. The delivery volume of exported tires increased by 5.87% year-on-year, and the export rate (volume) was 42.83%, up by 65,438 0.32 percentage points over the previous year. It is possible that the price of natural rubber will not fall, but the possibility of price increase is very high. Although technically suppressed by the neckline, the strength of the market outlook is still relatively strong. Relevant persons said that it is quite possible to speculate that Hujiao will go up. Tire export enterprises have cost advantages. When the upstream price of rubber is in a dilemma, the profit of downstream tires is increasing. After the cancellation of relevant preferential policies, the sales volume of passenger cars was affected by the overall economic slowdown, and the operating rate of tire manufacturers declined. Rubber is the main raw material of tires, and the proportion of rubber used in all-steel tires is about 40%-50%. Weak demand has led to a decline in tire prices and an impact on upstream raw material prices. According to estimates, when the rubber price drops by 40%, the domestic sales cost of truck and bus tires drops by about 27%. In the case that the price of tires is lower than the cost, tire enterprises still improve their profitability in the case of weak downstream demand. Moreover, tire enterprises also welcome the favorable factor of the expiration of the US special safeguard case. In the future, tire enterprises will have the cost advantage of export and boost the demand for rubber. Heavy truck sales are expected to stabilize. In June of 5438+00, the sales volume of heavy trucks was 44,000 vehicles, up 1.9% from the previous month. The sales volume has stabilized at more than 40,000 units for two consecutive months, and the sales volume has stabilized and rebounded. Because the rubber consumption of heavy trucks far exceeds that of other types of cars, the production and sales data of heavy trucks have always been our focus. If the production and sales of heavy trucks pick up, it will greatly benefit the rubber market. During the period of 1- 10, automobile manufacturers reduced their inventory by 40,000 vehicles, among which 10 data showed that the production and sales difference of heavy trucks was 2,546 vehicles, reflecting that the manufacturers remained cautious. However, since July, the absolute value of monthly production and sales difference of heavy trucks has obviously decreased, indicating that the inventory pressure of manufacturers has eased and the terminal demand has shown signs of improvement. After the traditional consumption peak season of "Golden September and Silver 10", heavy trucks have stabilized and rebounded, and the sales volume has basically bottomed out, and the downside space in the future is quite limited. Due to the limitation of technical level and working environment, the renewal cycle of heavy trucks in China is basically 3-5 years. After experiencing the blowout of heavy truck consumption in 2009 and 20 10, it gradually entered the peak period of renewal, and the aftermarket consumption is worth looking forward to. Industry-driven economic recovery From the latest data of electricity consumption growth, it can be seen that electricity consumption growth will continue, indicating that the economy is expected to recover moderately in the fourth quarter. Although industrial production and demand rebounded at the same time in September, the continuous decline in electricity consumption was mainly affected by destocking factors. The prices of coal, steel and cement rebounded at 5438+ 10 in June, indicating that the destocking process was weakened and industrial production was expanded. At the same time, the increase in infrastructure investment has led to a substantial increase in electricity consumption in heavy industry. Since June 65438+ 10, coal consumption has increased slightly, which indicates that the growth of electricity consumption will continue. Therefore, we expect that industrial activities will further drive economic recovery, and GDP is expected to rebound moderately in the fourth quarter. As can be seen from the above situation, the price trend of natural rubber is likely to rise. At present, the storage and storage of rubber and the approaching shutdown period of domestic production areas have played a strong supporting role in the market. Hujiao's main force hit a new high for two consecutive weeks. In addition, the export of tire enterprises has a cost advantage, heavy truck sales are expected to stabilize, and the industry will drive economic recovery. The possibility of natural rubber going up is very high. The mechanical process of natural rubber plasticization requires that natural rubber is the main rubber variety of raw rubber plasticization. Both open mill and internal mixer can achieve good plasticizing effect. When plasticating with an open mill, the low-temperature (40-50℃) thin pass (roll distance 0.5- 1mm) plasticizing method and segmented plasticizing method are usually used for the best results. When plasticating with an internal mixer, the temperature should be lower than 65438 055℃ and the time should be about 65438 03 minutes (depending on the plasticity requirements). With the increase of plasticizing time, the plasticity of plasticized rubber increases. But don't overdo it, otherwise the plasticity will become too high and the physical and mechanical properties will decrease. When plasticizing natural rubber, accelerator M is often added as plasticizer to improve the plasticizing effect. Accelerator M is suitable for open mill plasticization and internal mixer plasticization. After plasticizing natural rubber, in order to make the rubber molecular chain relax (commonly known as fatigue recovery) and have uniform plasticity, it needs to be parked for a certain period of time (4-8 hours) before it can be used in the next process. At present, the natural rubber used in China mainly includes domestic tobacco flake rubber and standard rubber, imported tobacco flake rubber and Malaysian standard rubber. Because the initial Mooney viscosity of the above rubber is different, the plasticizing time required to obtain the same plasticity is of course different. The plasticizing time sequence is: imported cigarette gum >; Domestic cigarette gum > domestic standard gum > Malaysian standard gum. Constant viscosity and low viscosity standard Malaysian rubber, oil-filled natural rubber, tire rubber and easy-to-handle rubber have low initial Mooney viscosity (generally less than 65) and can be directly mixed without plasticization. Rubber insurance is 20 18 1 1 month, and the enthusiasm of rubber farmers to cut rubber is hit by the continuous low price of rubber. To this end, Hainan Provincial Department of Finance and other departments jointly issued a notice to implement natural rubber price (income) insurance in Hainan Province. Once the rubber price is lower than a certain standard, it will trigger the insurance claim mechanism to ensure the income of rubber farmers.