Tire Cord Construction

Standard Test Methods for Steel Tire Cord. ASTM standard D2969-92 includes test methods for steel cords that are specifically designed for use in the reinforcement of pneumatic tires. It describes test methods determining steel cord construction, break strength, elongation at break,... 

Mechanical loss also varies with the cord construction variables such as denier per yarn strand, number of strands and number of twists per unit length ( 2 ). Significant changes In mechanical loss are also observed during the post treatments of grelge tire cords. These Include the steps of cord ten-slllzatlon, application of the adhesives and curing of tires. 

Ply twisting Twisting of the tire yarn onto itself the required number of turns per inch two or more spools of twisted yarn are then twisted again into a cord for example, if two 840-denier nylon cords are twisted together, an 840/2 nylon cord construction is formed if three 1300-denier polyester cords are twisted together, they give a 1300/3 cord construction. 

Steel tire cord is manufactured from high-quality steel, which is necessary because of the performance demands to which tires are subjected. The composition of a typical steel cord is illustrated in Table 14.5. The key mechanical properties governing a steel cord or wire are its tensile strength, elongation, and bending stiffness. A tire cord construction is normally defined by the structure, the length of lay, and the direction of lay. The hill description of a steel cord is given by... 

Subsequent to the twisting, the tire cord yarns are woven. Because normal fabric structures with nearly constant warp and weft density show less-optimal deformation and vulcanization characteristics, a special construction was developed for tire cord fabrics. Tire cords have only up to 10 weft threads made of cotton yarn per 10 cm and therefore have a very open structure. The weft has no carrying function in the tire. It serves only as a supporting thread to facilitate further processing steps. 

The performance properties of PEN present opportunities for replacement of rayon or polyamide in carcass construction. The use of PEN cord in these applications is currently being evaluated in both Asia and Europe. PEN has demonstrated acceptable flexural fatigue equivalent to polyethylene terephthalate (PET) and rayon. It has equivalent toughness to rayon, which is important for sidewall impact resistance. PEN s superior mechanical properties also afford opportunities to use less fiber in carcass construction enabling production of lighter-weight, more fuel-efficient tires. 

Thermosets A number of thermosets have been used as adhesives. Phenolic resins were used as adhesives by Leo Baekeland in the early 1900s. Phenolic resins are still used to bind together thin sheets of wood to make plywood. Urea resins have been used since 1930 as binders for wood chips in the manufacture of particle board. Unsaturated polyester resins are used for body repair and PUs are used to bond polyester cord to rubber in tires, and vinyl film to particle board, and to function as industrial sealants. Epoxy resins are used in the construction of automobiles and aircraft and as a component of plastic cement. 

The carcass ply/plies coat compound functions are basically the same as the steel breaker compound. Normally in the steel belted PCT the ply is textile cord of polyester or rayon fabrics which are soft and flexible. The truck radial steel tire normally uses a steel cord ply. Earthmover tires are of two basic constructions, ie, radial using steel and bias using textiles (see Tire cords). 

Unsaturated polyester resins have replaced lead for auto body repair, and polyurethanes (PUs) are being used to bond polyester cord to rubber in tires, to bond vinyl film to particleboard, and as industrial sealants. Epoxy resins are used in automotive and aircraft construction and as a component of plastic cements. 

The compounded rubber stock will be further processed for use. The process could be injection or transfer molding into a hot mold where it is cured. Tire curing bladders are made in this fashion. Extrusion of the rubber stock is used to make hose or tire treads and sidewalls. Another common process is calendaring, in which a fabric is passed through rolls where rubber is squeezed into the fabric to make fabric-reinforced rubber sheets for roofing membranes or body plies for tires. The actual construction of the final product can be quite complex. For example, a tire contains many different rubber components some of which are cord or fabric reinforced. All of... 

Use Thermal, acoustic, and electrical insulation (coarse fibers in bats or sheets) decorative and utility fabrics such as drapes, curtains, table linen, carpet backing, tenting, etc. tire cord as belt between tread and carcass filter medium reinforced plastics light transmission for communication signals reinforcement of cement products for construction use. 

The fluidized bed pyrolysis process developed at the Hamburg University aims at the recovery of products from plastics and tires. A pyrolysis unit for unshredded tires has been constructed. It produces gas, a carbon black, steel cord and an oil that has a... 

Hydraulic structures using scrap tires for bank protection include tire mats, revetment (retaining walls, seawalls, revet mattresses), and tire-concrete imits. In search for economical bank-protection structures, the use of scarp tires as a less-expensive alternative is desirable, considering the costs of the metal and concrete used in reinforced-concrete construction, especially in developing countries. Whole scrap tires can be utilized for surface erosion control, beach and slope protection, and stream bank stabilization. In these applications, scrap tires are banded together and partially or completely buried on imstable slopes. Tires can be used with other stabilization materials to reinforce an unstable highway shoulder or protect a channel slope remained stable and can provide economical and immediate solutions. In bank protection structures, tires are laced together by steel cables and used as a protective layer or mat over stream banks or soil embankments. The top, toe, upstream and downstream ends of the mattress are tied into the banks. Used tires with metal cords were shown to bean excellent construction material that can partially replace reinforced concrete for protection of river banks and canal walls [19]. 

Figure 2.75 shows the constructions of a standard bias (diagonal) ply tire and a radial ply tire. The major components of a tire are bead, carcass, sidewall, and tread. In terms of material composition, a tire on an average contains nearly 50% of its weight in actual rubber for oil extended rubbers (typically containing 25 parts of aromatic or cycloparafiBnic oils to 75 parts of rubber), it is less. The remainder included carbon black, textile cord, and other compounding ingredients plus the beads. 

The tire building is carried out on a flat drum, which is rotated at a controlled speed. The plies of rubber-coated cord fabric are placed in position, one over the other, and rolled down as the drum rotates, the inner lining being placed next to the drum and the ends of the drum being flanged to suit the bead configuration of the tire. The plies of rubber-coated textile are assembled in three basic constructions— bias (diagonal), radial, and bias belted. 

---