What type of rubber. What is car rubber made of? Sources of rubber and a brief excursion into history

In mechanical engineering, rubber is often used - a complex mixture in which the main component is rubber. Rubber has high elasticity, which is combined with a number of other important technical properties: high resistance to tearing and abrasion, gas and water resistance, chemical resistance, high electrical insulating properties and low specific gravity. The disadvantages of rubber include its low heat resistance and low resistance to the action of mineral oils (with the exception of special oil-resistant rubber).

Application of rubber... Rubber products are widely used in all sectors of the national economy. The range of rubber products is currently estimated at tens of thousands of items. The main application of rubber is in the production of tires.

In addition to tires, there are about 200 different rubber parts in a car: hoses, belts, gaskets, bushings, couplings, buffers, membranes, cuffs, etc.

Rubber has high electrical insulating properties, so it is widely used to insulate cables, wires, magneto, protective equipment - gloves, galoshes, rugs.

Composition of rubber. The composition of rubber includes rubber, reclaim, vulcanizing agents, vulcanization accelerators, fillers, softeners, antioxidants, dyes. Natural and synthetic rubber is the main raw material for rubber products. Currently, rubber materials are predominantly made from synthetic rubber, which is extracted from ethyl alcohol, oil, natural gas and other substances.

Regenerate - a plastic material obtained by processing old rubber products and rubber production waste. The use of reclaim reduces the content of rubber in the rubber mixture, reduces the cost of rubber products and somewhat increases their plasticity.

The main vulcanizing agent is sulfur. By changing the amount of sulfur in the composition of rubber compounds, it is possible to obtain rubber with different degrees of elasticity. The process of chemically combining rubber with sulfur when heated is called vulcanization... When producing elastic rubbers, sulfur is introduced in an amount of 1-4% by weight of the rubber. Rubber containing 25-35% sulfur is a hard material called ebonite. To reduce the duration and temperature of vulcanization, small amounts (0.5-2.5%) of accelerators (captax, lead oxide, etc.) are introduced.

Excipients there are active, inactive and special. Active fillers (enhancers) include carbon black, zinc white, kaolin and other substances that increase the mechanical properties of rubber (tensile strength and abrasion resistance). Carbon black is the main filler for tough rubber with high abrasion resistance. Inactive fillers include talc, chalk, infusorite earth, etc. They are introduced in order to increase the volume and reduce the cost of rubber. Special fillers include kaolin and asbestos, which impart chemical resistance to rubber, and diatomite, which increases the electrical insulation properties of rubber.

Softeners (plasticizers) impart softness, plasticity to the rubber compound and facilitate its processing.

Antioxidants are substances that protect rubber from aging.

Main types of rubbers... Reinforced rubber is called rubber, inside which gaskets made of metal mesh or spirals are inserted in order to increase strength and flexibility, which is especially important for such products as car tires, drive belts, conveyor belts, pipelines, etc. When it is prepared, it is laid in the rubber mixture a metal mesh coated with a layer of brass and coated with glue and subjected to simultaneous pressing and vulcanization.

According to the nature of the pores and the method of production, porous rubbers are divided into spongy - with large open pores, homogeneous cellular - with closed pores and microporous. The method for their production is based on the ability of rubber to absorb gases and on the diffusion of cans through the rubber. Porous rubber is used in the manufacture of shock absorbers, seats, window gaskets, tread layers of tires.

Hard rubber, or ebonite, has a dark brown or red color, heat resistance from 50 to 90 ° C, withstands high breakdown voltage (25-60 kV / min).

Rubber (from Latin resina - resin) (vulcanizate), an elastic material formed as a result of natural and synthetic rubbers. It is a reticulated elastomer - a product of rubber crosslinking by chemical bonds.

Getting rubber

Rubber are obtained mainly by vulcanization of compositions (rubber compounds), the basis of which (usually 20-60% by weight) is rubbers. Other components of rubber compounds are vulcanizing agents, accelerators and vulcanization activators (see), anti-aging agents, (softeners). The composition of the mixtures can also include a regenerate (plastic product of regeneration rubber, capable of re-vulcanization), retarders, modifiers, fragrances and other ingredients, the total number of which can reach 20 or more. The choice of rubber and composition is determined by the purpose, operating conditions and technical requirements to the product, production technology, economic and other considerations (see,).

Manufacturing technology of products from rubber includes rubber with ingredients in mixers or on rollers, production of semi-finished products (extruded profiles, calendered sheets, rubberized fabrics, cord, etc.), cutting and cutting of semi-finished products, assembly of blanks of a complex design or configuration using special assembly equipment and vulcanization of products in periodical apparatus (presses, boilers, autoclaves, shapers-vulcanizers, etc.) or continuous (tunnel, drum and other vulcanizers). At the same time, high rubber compounds are used, thanks to which they are given the shape of the future product, which is fixed as a result of vulcanization. Molding in a vulcanization press and in which molding and vulcanization of products are combined in one operation are widely used. The use of powdered rubbers and compositions and the production of molded rubbers by liquid molding methods from compositions based on are promising. With mixtures containing 30-50% by weight of S calculated on the rubber, get.

Rubber properties

Rubber can be considered as cross-linked, in which rubber constitutes a dispersion medium and a dispersed phase. The most important property rubber - high elasticity, i.e. the ability to large reversible in a wide temperature range (see).

Rubber combines properties (elasticity, shape stability), (amorphousness, high deformability at low volumetric compression) and (increasing the elasticity of vulcanization nets with increasing temperature, entropic nature of elasticity).

Rubber - a relatively soft, practically incompressible material. The complex of its properties is determined primarily by the type of rubber (see table. 1); properties can change significantly when combining rubbers different types or their modifications.

Elastic modulus rubber of various types with small deformations is 1-10 MPa, which is 4-5 orders of magnitude lower than for steel; Pausson's coefficient is close to 0.5. Elastic properties rubber are nonlinear and have a pronounced relaxation character: they depend on the loading mode, magnitude, time, rate (or frequency), deformation repetition and temperature. Reversible tensile deformation rubber can reach 500-1000%.

The lower limit of the temperature range of high elasticity rubber is mainly due to the glass transition temperature of rubbers, and for crystallizing rubbers also depends on temperature and speed. Upper operating temperature limit rubber associated with the thermal stability of rubbers and chemical cross-links formed during vulcanization. Unfilled rubber based on non-crystallizing rubbers are low. The use of active fillers (highly dispersed, SiO2, etc.) makes it possible to increase the strength characteristics by an order of magnitude. rubber and reach the performance level rubber from crystallizing rubbers. rubber is determined by the content of fillers and plasticizers in it, as well as the degree of vulcanization. Density rubber calculated as the volume-weighted average of the densities of the individual components. Similarly, the thermophysical characteristics can be approximately calculated (with a volumetric filling less than 30%) rubber: coefficient of thermal expansion, specific volumetric heat capacity, coefficient of thermal conductivity. Cyclic deformation rubber accompanied by elastic hysteresis, which determines their good damping properties. Rubber are also characterized by high frictional properties, wear resistance, tear and fatigue resistance, heat and sound insulation properties. They are diamagnets and good dielectrics, although conductive and magnetic rubber.

Rubber slightly absorb water and swell to a limited extent in organic solvents. The degree of swelling is determined by the difference in the solubility parameters of the rubber and the solvent (the smaller the higher the difference) and the degree of crosslinking (the value of equilibrium swelling is usually used to determine the degree of crosslinking). Known rubber, characterized by oil, gasoline, water, steam and heat resistance, resistance to the action of chemically aggressive media, ozone, light, ionizing radiation. With long-term storage and operation rubber are subject to aging and fatigue, leading to a deterioration in their mechanical properties, a decrease in strength and destruction. Life time rubber depending on the operating conditions, from several days to several decades.

Classification of rubbers

The following main groups are distinguished by purpose rubber: general purpose, heat resistant, frost resistant, oil and petrol resistant, resistant to chemically aggressive media, dielectric, electrically conductive, magnetic, fire resistant, radiation resistant, vacuum, frictional, food and medical, for tropical climates, etc. (Table 2); also get porous, or spongy (see), colored and transparent rubber.

Application of rubber

Rubber widely used in technology, agriculture, everyday life, medicine, construction, sports. The range of rubber products includes more than 60 thousand items. Among them: tires, transport belts, drive belts, sleeves, shock absorbers, seals, oil seals, cuffs, rings, etc., cable products, shoes, carpets, tubes, coatings and facing materials, rubberized fabrics, sealants, etc. More than half of the volume generated rubber used in the manufacture of tires.

Elastic materials have been familiar to man for a long time. They were then used mainly for domestic purposes. Today, without rubber and rubber, it is difficult to imagine the development of industry, transport and construction and communications, the daily life of people.

What came before

Even before Europeans discovered America, the Indians who lived there used rubber. It was received from tropical hevea juice... The dried juice was smoked to obtain a waterproof and resilient material. He went to the manufacture of containers for water, toys, objects of worship. They made primitive shoes and clothes from it.

In the middle of the 18th century, travelers brought rubber to Europe. However, for a long time they could not find a way to use it. Except for pencil erasers. It was believed that due to its drying and hardening, it has no prospects for practical use. In the next century, waterproof fabrics, bags and galoshes appeared, which hardened in cold weather and became soft in warm weather.

A hundred years after the appearance of rubber in the Old World, a method was invented that made it possible to make the elasticity of this material stable. It got the name vulcanization... Its essence is in mixing raw rubber with sulfur and then heating this mixture. The resulting product was called rubber. It began to be widely used as a sealant and electrical insulator. At the beginning of the twentieth century, due to the growing demand for rubber, the problem of producing synthetic rubbers in industrialized countries was solved.

Where does latex go

Natural rubber is extracted from rubber treesthat grow in rainforest or on special plantations. Such a tree begins to produce sap after seven years. To do this, a spiral recess is made on it with a knife, through which the flowing white juice, called latex, enters the container. After a few hours, about one and a half hundred grams are typed. After thickening and drying, lumps of natural rubber are formed. This procedure can be carried out every two days.

In total, natural rubber reaches 40% in general production and the consumption of all types of rubbers. It is approximately 9 million tons.

Untreated rubber dissolves in gasoline to form rubber glue and other organic solvents. After vulcanization, it only swells and does not dissolve.

In addition to gasoline, it dissolves in benzene, chloroform, carbon disulfide and other hydrocarbons. It is practically insoluble and does not swell in alcohol, water and acetone.

More than half of natural rubber is used for tire production. In the countries of Southeast Asia (Vietnam, Indonesia, Malaysia and Thailand), large-scale production is organized.

How rubber is made

Both elastic materials are inextricably linked. Rubber is obtained from natural or synthetic rubber by vulcanization. A filler is added, which is most often soot. Heated up 130-160 degrees rubber begins to interact with sulfur. During this technological process rubber molecules are crosslinked into a single network using sulfur atoms. This dramatically increases its elasticity and hardness, strength properties. Swelling and solubility with organic solvents is regulated.

In addition to sulfur, metal oxides, amine-type compounds, accelerating catalysts, and other chemical components are used for vulcanization. They provide the desired ductility, anti-aging properties and other performance characteristics. As a result, the rubber is converted into rubber. Material with different degrees of elasticity is formed depending on the sulfur content. The softest rubber is obtained with a minimum sulfur content, and the hardest is the one in which it is one third or more.

In the manufacture of rubber, certain qualities are assigned to it for the production of products from it:

• Acid resistance.
• resistance in aggressive environments.
• Oil and petrol resistance.
• resistance to high and low temperatures.
• Ozone resistance.
• Electrical conductivity, etc.

Rubber is widely used to make tires for vehicle, various hoses and seals, conveyor belts, household, hygiene and medical products.

What are the similarities and differences

Rubber and rubber are similar primarily in their elasticity and in the fact that they can be recycled. Their differences are more significant.

Raw rubber:

1. Not suitable for industrial production. No more than 1% of the extracted natural rubber is used in the world. Mostly in the form of rubber glue.
2. It has low strength and high stickiness, which is strongly manifested at high temperatures. In the cold, it hardens and breaks. It acquires useful qualities only after vulcanization.
3. At room temperature, its aging begins, resulting in a loss of strength and elasticity.
4. When the temperature rises to 200 degrees, it decomposes to form low molecular weight hydrocarbons.
5. Dissolves with organic solvents such as gasoline.
6. Serves as a raw material for the production of rubber.

Rubber obtained as a result of vulcanization of rubbers is used for the mass production of many thousands of different products.

It is used to make:

1. Tires for vehicles and aircraft.
2. Various seals used in industry and construction, different types technology.
3. Electrical insulating materials.
4. Drive belts, fluid hoses.
5. Floor coverings and insulating plates.
6. Rubber footwear and waterproof clothing.
7. Means of protection against chemical, radiation and bacteriological effects (suits, gloves, boots, etc.).
8. Medical equipment and hygiene products.
9. Accessories for clothes, etc.

), the basis to-rykh (usually 20-60% by weight) are. Dr. components of rubber compounds - vulcanizing agents, accelerators and (see), anti-aging agents, (). The composition of the mixtures may also include a regenerate (a plastic rubber product capable of being repeated), retarders, modifiers, blowing agents, fragrant substances and other ingredients, the total number of which can reach 20 or more. The choice and composition is determined by the purpose, operating conditions and technical. requirements to the product, production technology, economical. and other considerations (see,).

The technology for the production of rubber products includes with ingredients in mixers or on rollers, the production of semi-finished products (extruded profiles, calendered sheets, rubberized, etc.), cutting and cutting of semi-finished products, assembly of blanks of a complex design or configuration using special. assembly equipment and products in apparatuses periodically. (presses, boilers, shapers-vulcanizers, etc.) or continuous (tunnel, drum and other vulcanizers). In this case, a high one is used, thanks to a cut they are given the shape of the future product, which is fixed as a result. Vulcanization molding is widely used. press and, with to-ryh molding and products are combined in one operation. The use of powdered and compositions and the production of molded rubbers by liquid molding methods from compositions based on are promising. With mixtures containing 30-50% by weight of S, calculated on, get.

Properties.Rubber can be considered as sewn, in a cut it is, and fillers are a dispersed phase. The most important property of rubber is high elasticity, that is, the ability to large reversible in a wide interval t-p (cm. ).

R ezina combines sv-va (elasticity, shape stability), (amorphousness, high deformability at low volumetric compression) and (increase in the elasticity of vulcanized nets with increasing t-ry, entropic nature of elasticity).

R ezina is a relatively soft, almost incompressible material. The complex of its sv-in is determined primarily by the type (see table. 1); cv-va can significantly changedull when combining decomp. types or their modifications.

Elastic modulus of rubber decomp. types at small is 1-10 MPa, which is 4-5 orders of magnitude lower than for steel; coeff. Pausson is close to 0.5. Elastic properties of rubber are nonlinear and have a pronounced relaxation. character: depend on the loading mode, magnitude, time, speed (or frequency), repetition and t-ry. reversible elongation of rubber can reach 500-1000%.

Lower the limit of the temperature range of rubber high elasticity is due to Ch. arr. t-swarm glass transition, and for crystallizing depends also on t-t and speed. Top. the temperature limit of rubber operation is associated with thermal. resistance and transverse chemical. bonds formed at. Unfilled rubbers based on non-crystallizing ones have a low. The use of active (highly dispersed, SiO 2, etc.) makes it possible to increase the strength characteristics of rubber by an order of magnitude and achieve the level of indicators of rubbers from crystallizing. rubber is determined by the content in it and, as well as the degree. The density of the rubber is calculated as the volume-weighted average of the densities of the individual components. Similarly m. B. approximately calculated (with a volumetric filling less than 30%) thermal physics. rubber characteristics: coeff. thermal. expansion, beats volumetric, coeff. ... Cyclical. deformation of rubber is accompanied by elastic hysteresis, which determines their good shock absorption. Holy Island. Rubber is also characterized by high friction properties, wear resistance, resistancetear and fatigue, heat and sound insulation. St. you. They are good, although m. B. received conductive and magnetic rubbers.

R ezins slightly absorb and swell to a limited extent in org. p-amateurs. The degree is determined by the difference between the parameters of p-rimity and p-solvent (the less, the higher this difference) and the degree of cross-linking (the equilibrium value is usually used to determine the degree of cross-linking). Known rubber, characterized by oil, benzene, water, steam and resistance to chemical action. aggressive environments, light,. When lasts. storage and use of rubber are subject to aging and fatigue, leading to deterioration of their fur. sv-in, reduction and destruction. Service life of rubbers depending on operating conditions from several. days to several. decades.

. A trace is distinguished by purpose. main groups of rubbers: general purpose, heat-resistant, frost-resistant, oil-and-petrol resistant, resistant to chemical action. corrosive media, dielectric, electrically conductive, magnetic, fire-resistant, radiation-resistant, vacuum, frictional, food. and honey. destination, for tropical conditions. climate, etc. (Table 2); get also porous, or spongy (see), colored and transparent rubbers.

Application.Rubber is widely used in technology, p. x-ve, everyday life, medicine, building, sports. The assortment includes more than 60 thousand items. Among them: tires, transport belts, drive belts, sleeves, shock absorbers, seals, oil seals, cuffs, rings, etc., cable products, shoes, carpets, tubes, coatings and facing materials, rubberized, vol. 3, M., 1977 , from. 313-25; Koshelev F.F., Kor-nev A.E., Bukanov A.M., General technology rubber, 4th ed., M., 1978; Dogadkin B.A., Dontsov A.A., Shershnev V.A.,2nd ed., M., 1981; Fedyukin D.L., Makhlis F.A., Technical and technological properties rubber, M., 1985; The use of rubber technical products in the national economy. Reference manual, M., 1986; Zuev Yu. S., Degteva TG, Durability in operating conditions, M., 1986; Lepetov V.A., Yurtsev L.N., Calculations and design,3rd ed., L., 1987. F.E. Cooperman.

It is difficult to imagine today's rich and technologically advanced human life without such a material as rubber. But a few centuries ago about rubber products high Quality one could only dream. Now this material is indispensable in medicine, industry, technology, household everyday life.

The appearance of rubber in people's lives happened quite suddenly, after Columbus discovered America. It takes its origin from rubber, which was made from the hevea tree. Having discovered a new continent, the traveler drew attention to the development of the Indians and their household items. Most of all, he was struck by the ball, which children played with, made of an unknown material. The weighty black sphere was quite bouncy and lightweight, bypassing the quality of ordinary European leather balls.

So Columbus learned about the trees growing in Indonesia and Brazil, the incisions on which gave a stretching latex sap. It was he who gave rise to a new material from which rubber products are made in modern times. The rubber of that time was quite often used in clothing or construction, due to its non-wetting properties. Over the years, many experiments have been carried out with rubber, both physical and chemical, in the hope of improving its properties.

And only in 1893 the scientist Goodyear was able to make from rubber modern look rubber, which is so widely used these days. Thanks to the correct heat treatment, the rubber was able to obtain the desired properties and forever turn into a universal and durable rubber. In the twentieth century, rubber began to be actively used as a high-quality and reliable insulator, laying thousands of new electrical routes around the world.

Further more. Rubber has become integral part industry and human life. Rubber elements were present in household appliances, furniture, clothes, shoes, hygiene items, dishes. In large industrial areas, rubber has become an integral part of all processes. Today it is difficult to imagine how car tires, cut-off wheels, parts of spare parts would look like, construction tools and much more, if rubber had not been produced once, like separate species material.

The USSR was able to put into production rubber not only natural origin, but also synthetic, having learned to extract and synthesize rubber, and then rubber itself from natural gases, oil, alcohol. Western scientists for a long time did not recognize this fact as possible, since for them this technology was unknown, but after years, European and American scientists recognized synthetic rubber as a reality. This allowed the USSR to step far ahead in terms of technology and significantly save the country's budget, avoiding expensive purchases of raw materials for rubber from Brazil or Indonesia.

Synthetic rubber was practically not inferior in properties to the natural component, but its low elasticity did not allow making such important industrial goods as automobile and aircraft tires from it. Over time, thanks to modern developments and constant experiments with temperature conditions and chemical components, this problem has been completely resolved.

Thus, the generous nature and scientific factors were able to give the world such a material as rubber, which allows us to develop modern technical and medical developments, improving them with their natural properties. Today, rubber is one of the most durable, enduring and versatile materials of mankind.