Yuan Lei Small Classroom | Common Inorganic Fillers for Tire Rubber

Release time:

2024-01-29 09:35


Yuan Lei Small Classroom | Common Inorganic Fillers for Tire Rubber


Tire is one of the main branches in the field of rubber, in the tire rubber, the amount of rubber filler has accounted for the amount of tire rubber formula.2/3Thus, the rubber filler is the most important compounding material in the tire rubber composition. At present, the tire rubber commonly used functional filler has the following:




1. Carbon black

Carbon black is a widely used chemical products, about 70% of the carbon black used in the tire industry, which can not only improve the strength of the product, but also improve the processing performance, and give the product wear resistance, tear resistance, heat resistance, cold resistance, oil resistance and some special properties, so that the service life of the product is extended.

2. White carbon black

Because of its unique structure and surface chemical properties, silica has been widely used in the tire industry, including truck tires, car tires, agricultural tires, etc.; according to the cord material, it is divided into all-steel, semi-steel and fiber cord tires, The use of parts include tread, belt, sidewall and steel wire adhesive.

Silica with surface hydroxyl and adsorption of water, usually need to be surface modification can be applied to the field of rubber, the most commonly used in combination with silica modifier is silane coupling agent, the hydroxyl formed after hydrolysis and silica surface active groups react to form hydrogen bonds, and then condensed into covalent bonds, making the silane coupling agent and silica solid combination.

3. Calcium carbonate

Calcium carbonate used in tires is mainly ultrafine active calcium carbonate, which means that an appropriate amount of active agent is added to cover the surface of the particles in the process of manufacturing calcium carbonate to increase the activity of calcium carbonate. The reinforcing performance of activated calcium carbonate is larger than that of light calcium carbonate, and it can be used as a reinforcing agent and filler for white products. The reinforcing performance varies with the particle size, and the particle size is less than 1 μm, and the reinforcing effect is strong. At present, active calcium carbonate mainly refers to ultrafine active calcium carbonate.

Because the surface of ultrafine active calcium carbonate particles is covered with active covering layer, it has good affinity with rubber, is easy to disperse during mixing, has low heat generation of rubber compound, small breaking permanent deformation, good elasticity, certain reinforcement and low price. It is commonly used to replace semi-reinforced carbon black or partially replace other carbon black, and is used for agricultural tires and light truck tire cord rubber, and load truck tire inner rubber, automotive tire inner tire rubber, cushion belt rubber and white sidewall rubber, especially in the inner and outer tire rubber of the car tire, to reduce product costs, improve the process performance and certain physical properties of the rubber compound.

Foreign large tire companies in high or ultra-high performance radial tire inner liner rubber has used calcium carbonate as a filler, so in ordinary radial tires can also be considered to increase the amount of calcium carbonate, in order to reduce the rubber content, to a certain extent, can also improve the rubber process performance.

4. Montmorillonite

Montmorillonite (MMT) is a layered silicate, which can be filled into natural rubber by organic modification, which can significantly increase the tear strength and hardness of NR. When the number of filling is small, the comprehensive performance is better than that of silica, and it is a cheap natural inorganic filler that can replace silica.

5. Barium sulfate

Barium sulfate is mainly used as an inert filler or colorant in rubber. The vulcanized rubber has the characteristics of small compression deformation and large flexibility, which can give the product acid resistance, so it is often used as a characteristic filler in acid-resistant products.

At present, most of the steel wires used in the tire bead should be acid treated to remove the surface oil and improve the adhesion with the rubber. Therefore, it is necessary to use a certain amount of barium sulfate in the steel wire rubber to enhance its acid resistance. Previously, precipitated barium sulfate was used, the adhesive force between the rubber compound and the steel wire was low, and the surface of the steel wire was seriously sprayed. However, when active barium sulfate was used, the general performance of the rubber compound was similar to that of precipitated barium sulfate, but the extraction force of the steel wire was obviously improved, the extrusion process performance was excellent, the bead spray phenomenon was obviously reduced, the durability of the finished product was normal, and the price of active barium sulfate was lower than that of precipitated barium sulfate, which could improve economic benefits. Therefore, active barium sulfate can completely replace the traditional precipitated barium sulfate for tire steel rubber.

6. Calcium sulfate

At present, calcium sulfate is mainly used for rubber modification in the form of calcium sulfate whiskers. Calcium sulfate whiskers are readily available and inexpensive, and can effectively reduce costs. Therefore, calcium sulfate whisker modified rubber has high cost performance and is particularly suitable for use as high-performance large and medium-sized truck tire sidewall rubber, which can effectively improve the environmental stress resistance of tires and make tires not easy to crack.

7. Graphite

Due to the high thermal conductivity and low friction coefficient of graphite, its heat generation in isoprene rubber vulcanizates is small. This ensures that the compound has good fatigue resistance. Isoprene rubber has good physical and mechanical properties, widely used in tire tread rubber, carcass rubber and sidewall rubber, therefore, graphite filled isoprene rubber as tire rubber can generally improve the fatigue resistance of tire products.

8. Carbon fiber

Carbon fiber as a filler can be used in many parts of the tire system, such as the sidewall, tread and bead, and its role is also different. Pneumatic tires generally have sidewalls, and it has been conventionally desired that the sidewalls have good bending fatigue resistance, scuffing resistance, and abrasion resistance. A variety of discontinuous (non-woven) fibers have been used to increase the stiffness and modulus of vulcanized rubber. At present, the bead core material used is usually steel wire or steel wire rope strand, but there are also patents in which carbon fiber is used instead of steel wire.

9, Carbon Nanotubes

The unique structure of carbon nanotubes (CNTs) makes it have excellent properties such as ultra-high strength, great toughness, unique electrical conductivity and thermal conductivity. As a reinforcing agent, it can greatly improve the mechanical properties of composite materials. It can provide excellent reinforcement for rubber matrix and improve its fatigue resistance. Its thermal conductivity, tear resistance and wear resistance are excellent. Therefore, CNTs are used to fill rubber composite materials, it is of great significance to prepare tires with low rolling resistance.

10. Fiberglass

Glass fiber for rubber reinforcement is generally made of glass (I. e., alkali-free glass). If high strength is required, S glass (I. e., high strength glass) can be used. Generally, glass yarns for tires are treated with monofilaments using resorcinol formaldehyde latex as a binder to prevent mutual wear between monofilaments. Glass fiber reinforced tires are now widely used in cars and will be widely used in trucks in the future.

11. Other fillers

At present, the research on rubber fillers other than traditional fillers is mainly focused on environmentally friendly substances, such as starch, cellulose and lignin; functional substances, such as magnetic powder and metal methacrylate; waste recycling substances, such as rubber powder.

Tire, rubber, performance, calcium carbonate, barium sulfate, filler, use, compound,

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