Butyl Rubber
Butyl rubber is a synthetic rubber made from isobutylene and a small amount of isoprene. The finished product is prone to leaking, and it is usually used to manufacture car and airplane tires.
Butyl rubber is an isobutylene-isoprene copolymer that was first introduced into industrial production in 1943.
The major advantages of butyl rubber are:
Good air tightness, resistance to heat, ozone, aging, chemicals, and shock absorption, as well as electrical insulation.
The disadvantages are:
Slow vulcanization and poor processing properties.
contact：cathy@brightrubberplastic.com
Main uses:
Manufacturing various types of tire inner tubes, tire airtight layers, various types of sealing gaskets, as well as serving as the lining of corrosive liquid containers in the chemical industry, pipes, and conveyor belts. Agriculture uses it as a waterproofing material.
In 2005, China's consumption of butyl rubber was close to 150,000 tons, of which 30,000 tons were produced domestically. 80% of the consumption relied on imports, with the annual growth rate of imports from 1999 to 2004 reaching 26.9%. Due to the continuous rise in the international oil market, the price of butyl rubber has also risen continuously in recent years. The price of butyl rubber products has also risen, but the overall increase in price is more than 30%, far exceeding the price increase of butyl rubber, which has increased by a factor of several times. As a result, many companies that use a lot of butyl rubber have turned their attention to the best alternative product of butyl rubber - butyl reclaimed rubber. Butyl reclaimed rubber, in addition to similar properties to the original polymer, also has certain special compounding advantages that improve dimensional stability, heat resistance, and lower the risk of scorching. It also has good gas
tightness, similar to the original butyl rubber. Compared to synthetic rubber, it retains the various properties of the original rubber better. Therefore, butyl reclaimed rubber is a good choice of material for good business operation and the manufacture of tire inner tubes. Butyl rubber contains a small amount of isoprene, so its saturation level is lower. Its vulcanizate's resistance to aging is very good, indicating that it has excellent resistance to oxidation. Experiments have also proved that the role of oxygen in the recycling of scrap vulcanized butyl rubber is small, so the recycling of de-sulfurized butyl rubber is more difficult than that of natural rubber.
At present, there are six or seven kinds of butyl reclaimed rubber production processes in China, mainly including steaming, frying, extrusion, microwave, radiation, high-temperature continuous catalytic method, and chemical mechanical method, etc. No matter which method is used, the goal is to use economical and scientific methods to transform the networked structure of waste butyl rubber into a linear structure. With the rapid development of China's tire industry, the consumption of butyl rubber has risen rapidly, especially with the rapid development of radial tires. In addition, the national standard for "Dingji Hua of Medical Bottle Caps" has been issued, which has led to the strong demand for butyl rubber in both domestic and foreign markets, promoting the development of butyl reclaimed rubber.
However, due to the shortage of raw materials for butyl reclaimed rubber production in China, the price of waste butyl inner tubes has risen from around 20,000 yuan per ton two years ago to around 6,100 yuan per ton currently, while the price of waste rubber caps has risen from around 800 yuan per ton to around 3,800 yuan per ton currently, and the price of medical bottle caps has risen from around 1,000 yuan per ton to around 2,000 yuan per ton currently. Although the price of butyl reclaimed rubber has risen, it has not kept pace with the sharp rise in the price of waste butyl rubber, causing many butyl reclaimed rubber manufacturers to go from making high profits to making only marginal profits or no profits at all. An analysis of the reasons for this shows that the main reason is the production process and method, as well as the low physical properties of the butyl reclaimed rubber produced, which can only be sold at low prices, leaving manufacturers with no profits and wasting a large amount of valuable resources. The traditional desulfurization methods are currently very popular in China, and most manufacturers use dynamic tank desulfurization or fire-roasted tank desulfurization. The two methods have the following drawbacks: Dynamic desulfurization only provides high temperature and high pressure desulfurization conditions, and the desulfurization time is long. In addition, expensive softening additives need to be added. The key is that it cannot provide frictional and compressive force on the desulfurization raw material, which can cause surface carbonization and internal non-penetration of the raw material, resulting in unevenly dispersed particles on the product surface and affecting product quality. Fire-roasted tank desulfurization is even worse than dynamic desulfurization in terms of accurate temperature control, and carbonization and Four, the loss of tensile strength and other physical indicators is small. Before processing, random samples of the used tires are taken for measurement to obtain an average value. The tensile strength value of the regenerated rubber after processing is only 0.3-0.5MPa lower than the average value before processing, which is unparalleled by the desulfurization method. The vulcanization temperature of the kneading method is controlled for the source of butyl rubber raw materials, which is diverse for butyl waste inner tubes. For example, the high tensile strength can reach 10MPa or above, and the low can only reach 6.3MPa. The specific gravity is also the same.
After long-term observation and experimentation, it has been found that the tensile strength and specific gravity are high, and the critical temperature is low. Conversely, the critical temperature is high. The content of butyl rubber determines the critical temperature of desulfurization. Before each batch of raw materials is processed, it is necessary to randomly inspect the tensile strength or specific gravity of the raw materials. According to the actual data, the desulfurization temperature (i.e., the critical temperature) can be calculated for butyl rubber capsules and other butyl raw materials. The desulfurization temperature is relatively high for rubber vulcanized by sulfur-sulfur vulcanization system or tin chloride vulcanization system. The temperature has an impact on the Mendel viscosity, which is one of the physical indicators of butyl regenerated rubber. The quality of butyl regenerated rubber is good or bad, and the second physical indicator is the Mendel viscosity, followed by tensile strength and tensile elongation at break. Currently, due to the fact that domestic manufacturers of large-sized butyl inner tubes use butyl reclaimed rubber with a MI (ML + 1 + 4) of 100℃ 55±5 for their production, while manufacturers of bicycle and motorcycle inner tubes and other small-sized inner tubes require a MI (ML + 1 + 4) of 100℃ 45±5, some specialized manufacturers even require a MI (ML + 1 + 4) of 100℃ below 40. Higher MI values result in higher tensile strength and better processability, while lower MI values result in lower tensile strength and better processability.
In the kneading method of dechlorination, to ensure the strength indicators, softeners (mechanical oil) are added to adjust the MI critical temperature and thermal oxidation control. Butyl rubber is an artificially synthesized rubber, and controlling the critical temperature is the key when using the kneading method of dechlorination. When the raw materials are kneaded in the kneader and subjected to friction and compression, they heat up and reach the critical temperature, at which point the swelling, activation, and mechanical dispersion processes have been completed. The thermal oxidation process can be stopped by timely cooling, and the thermal oxidation process can be controlled by controlling the critical temperature and timely cooling. This is crucial.
It is necessary to promptly投入开炼机进行降温控制污染方法. The kneading method of dechlorination in the production process of butyl reclaimed rubber only produces a small amount of misty smoke at the critical temperature. An air collector is installed above the kneader, and the fan sends the smoke into a water curtain condensation and smoke removal device, which can be fully discharged without harm to the environment. The condensate is recycled, and the floating matter in the water is skimmed out to be used as softeners or as fuel. Nitrile rubber is made by polymerizing butadiene and acrylonitrile through an emulsion polymerization process. Nitrile rubber is mainly produced by the low-temperature emulsion polymerization method. It has excellent oil resistance, high wear resistance, good heat resistance, strong adhesion, but its disadvantages are poor low-temperature resistance, poor resistance to ozone, and poor electrical properties. Its elasticity is slightly lower.
Nitrile rubber is mainly used to manufacture oil-resistant rubber products. nitrile butadiene rubber
This is a synthetic rubber made by copolymerizing butadiene and acrylonitrile. It is a rubber that has good resistance to oil (especially alkane oil), and good aging resistance. The content of acrylonitrile (%) has five grades: 42-46, 36-41, 31-35, 25-30, and 18-24. The higher the content of acrylonitrile, the better the oil resistance, but the cold resistance decreases. It also has good water resistance, air tightness, and excellent adhesion properties. It is widely used to make various oil-resistant rubber products, such as oil-resistant gaskets, oil-resistant washers, oil-resistant sleeves, oil-resistant hoses, oil-resistant packaging, oil-resistant rubber tubes, printing rollers for dyeing, and cable rubber materials. It is an indispensable elastic material in industries such as automobiles, aviation, petroleum, and photocopying.
Basic properties
Nitrile rubber has excellent oil resistance, second only to polysulfide rubber and fluorine rubber, and has good wear resistance and air tightness. The disadvantage of nitrile rubber is poor resistance to ozone and aromatic hydrocarbons, halogenated hydrocarbons, ketones, and esters. It is suitable for making insulating materials.
Main uses
Nitrile rubber is mainly used to make oil-resistant products, such as oil-resistant hoses, rubber strips, rubber diaphragms, and large oil bags. It is often used to make various oil-resistant molded products, such as O-rings, oil seals, cups, valves, bellows, and rubber boards and wear-resistant parts.