Belted radial tires

Insoluble Sulfur. In natural mbber compounds, insoluble sulfur is used for adhesion to brass-coated wire, a necessary component in steel-belted radial tires. The adhesion of mbber to the brass-plated steel cord during vulcanization improves with high sulfur levels ( 3.5%). Ordinary rhombic sulfur blooms at this dose level. Crystals of sulfur on the surface to be bonded destroy building tack and lead to premature failure of the tire. Rubber mixtures containing insoluble sulfur must be kept cool (<100°C) or the amorphous polymeric form converts to rhombic crystals. 

The role of the mbber compounds which are used ia these basic components is threefold (/) to provide the coatact area betweea the vehicle and the surface (2) to provide the cohesive material that holds the tire together such that it acts as an iategral unit and (J) to provide protection for the ultimate strengthbeating components, ie, the textiles, steel beads, and steel breakers ia steel belted radial tires. 

An example that shows that the cohesive strength of a material is less than that of the adhesional strength of the interface is that of the nominal 50,000 mile steel belted radial tire. It is a simple calculation to show that, on average, a tire leaves a monolayer of rubber particles on the road every time it makes a rotation. In essence, the strength of the adhesional bonding between the road and the tire is greater than that of the rubber within the tire. 

What do bamboo stalks, mud bricks, steel-belted radial tires, fiberglass fishing rods, reinforced concrete, and the heat tiles on a space shuttle have in common The answer is that these materials are all composites. A composite is a material consisting of two or more components with overall properties different from and superior to either or any one of the individual components. For example, many pleasure boats today have hulls made of a composite material called reinforced plastic that contains glass, plastic, carbon, or some other type of fiber embedded in plastic. The composite material is stronger, more durable, and less dense than the fibers or plastics of which it is made. 

In theory, almost any polymer can be used as a reinforcement in an advanced composite. By far the most common polymer fiber, however, is aramid, better known by its trade name, Kevlar. Developed originally for use in belted radial tires, aramid is an aromatic polyamide in which benzene fragments (C6H4) alternate with peptide groups (NHC = Q) in forming a polymeric structure ... 

Pyrolysis produces three principal products - pyrolytic gas, oil, and char. Char is a fine particulate composed of carbon black, ash, and other inorganic materials, such as zinc oxide, carbonates, and silicates. Other by-products of pyrolysis may include steel (from steel-belted radial tires), rayon, cotton, or nylon fibers from tire cords, depending on the type of tire used. 

The body armor described here is constructed of DuPont Kevlar Fabric. This cloth is woven from strands of Kevlar Aramid Fiber, a material developed by DuPont as a replacement for steel wire belted radial tires.This material is lighter than ballistic nylon and pound for pound it s several times as strong as steel. When Kevlar is used in multiple layers, it can effectively stop bullet penetration and greatly reduce internal injuries from blunt trauma. Finished armor pads are light, flexible and easily concealed. 

Steel-belted radial tires are the predominant type of tire currently produced in the United States... 

The adhesion between rubber and brass-plated steel (e.g., steel tire cords for belted radial tires) has been the subject of much study and speculation. Brass plating is the major method of obtaining adhesion between natural rubber and the steel of tire cords. Over the years there has been much speculation about its mechanism, but there is agreement on one aspect of the adhesion of natural rubber to brass-plated steel the actual adhesion between the natural rubber and the brass-plated cord, formed in situ during the vulcanization process, is an interfacial layer of sulfides and oxides of copper (Buchan, 1959 van Ooij, 1979, 1984). 

The adhesion between rubber and brass-plated steel (e.g., steel tire cords for belted radial tires) has been the subject of much study and speculation. 

About 70% of natural rubber consumption goes into tire production while the remaining 30% is used by the nontire sector. There is some substitutability of various synthetic elastomers for natural rubber, but it is rather limited. This substitutability is restricted for the tire sector, which globally uses almost half of its total rubber requirement as natural rubber. In the short term, it is technically very difHcult to make major substitutions of synthetic rubber for NR use. Some applications are very critical, such as the use of NR in wire adhesion compounds for the production of steel-belted radial tires. Also, the use of natural rubber is very critical in the production of very large off-the-road tires. However, the natural rubber requirements of the nontire sector were only 29% of its total rubber usage in the year 2000. The nontire sector only used about 22% of its total rubber requirement as natural rubber in 2010. Many times it is easier in the nontire sector to substitute specialty syn-... 

Zinc oxide is essential in rubber technology because it is the most commonly used activator for sulfur cure systems. Just about every rubber compound that uses sulfur as the vulcanizing agent will most likely contain a small amount of zinc oxide to activate the cure. Also zinc is alloyed with copper to form brass. Special brass-plated steel tire cord is a primary reinforcing material for producing steel-belted radial tires. The brass coating of the steel tire cord enables very good rubber-to-metal adhesion. Therefore, zinc metal and zinc oxide are very important to the rubber industry. 

Since belted radial tires were introduced in 1948 by Michelin, steel as well as polyester and aramid have been used to make the tire cord for the radial belt. Steel has historically also been used to make the bead wire in tire construction. In addition, steel has been used to manufacture the cable that is used in making rubber mining conveyor belts. Lastly, in the automotive industry, many times rubber parts are made that are composites of rubber and steel. Examples of these parts are seen with motor mounts and bushings. 

From time to time in the last three decades there have been spot shortages of steel tire cord for belts, which have actually restricted the production of steel-belted radial tires. 

Sanderson discovered the adhesion of brass to sulfiir-vulcanizable rubber over 100 years ago. Interest in the mechanism of this bond formation has been spurred on by the advent of the steel-belted radial tire. Buchan and Rae postulated that chemical bonds are formed between copper atoms on the brass surface and sulfur atoms of crosslinked polymer molecules ... 

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