TYRE CARCASS

G. CoraHo, "Historical Review of Light-Duty Tyre Carcass Reinforcement and the State of Current and Next Generation Technology," Conference Preprints ACS, PuhherTdivision, Philadelphia, Pa., May 1995, p. 13. 

Other versions of the machine are designed for specific purposes, e.g., a twin ram machine capable of producing a continuous extrusion, and versions capable of applying tread rubber directly to a buffed tyre carcass whilst simultaneously forming the tread pattern. 

Rubber coated fabric is cut to give a bias to the fabric on its application to the tyre carcass. The knife angle can be adjusted in the cutting machine. 

Rubber lining Rubber roll covering Tyre carcass Tyre tread Moulded tubes Footwear Soles and heels Mechanical goods Ebonites or hard rubber... 

E. Dommershuijzen, "Super Single Truck Tyre Carcasses A Challenge For P-Aramid Fibers," Conference Proceedings ACS, Rubber Division, Odando, Fla., Paper 53, Oct. 1993, p. 7.012. 

General-purpose furnace carbon black GPF N660 Oil furnace 63 36 Medium reinforcement and modulus, good flex and fatigue resistance, low heat build-up, used in tyre carcass, inner lines and sidewalls, sealing rings, cable jackets, hose and extruded goods. 

Tyre Carcass Properties of Crystallizable Solution Rubbers... 

Building tack or tack strength, i.e. the force required to separate two uncured polymer surfaces after they have been brought into contact, is another important property desired in a tyre carcass rubber. Of course, the upper limit of tack strength is a rubber s green strength. 

The low air permeability properties of ENR-50 make it suitable for these applications. Although tack and cured adhesion values of the neat polymer to a tyre carcass stock are low, ENR-50/NR blends have higher adhesion values than those of Cl IIR/NR to a carcass stock. ENR-50/NR compounds also have faster cure rates, high tensile strength and elongation at break, higher tear resistance and better De Mattia flex and cut growth resistance. ... 

Figure 3.1 Off-the-road (OTR) tyre retreaded with compound containing 40% truck tyre 40 mesh crumb (a) tyre carcass being retreaded with the compound (b) moulded tyre ready for use and (c) tyre fitted onto the OTR vehicle. Reproduced with permission from Polymer Recyclers. 2014, Polymer Recyclers Ltd...

Figure 5.1 Passenger tyre carcasses retreaded with compounds containing 5-30% DevulCOi rubber prior to moulding. Reproduced with permission from the DevulCOi Research Project Consortium (Lead Partner Smithers Rapra, Shawbury, UK), UK. 2012, DevulCOi...

The quality of the crumb with regard to contamination such as metal and fabric (from the tyre carcass) is very important, as small amounts of these can adversely affect important final properties such as tensile strength and elongation. 

The functions of the inner liner in a tubeless tyre are to retain air in the tyre, to maintain air pressure at the correct level (which is important in terms of rolling resistance and tyre life) and to prevent air and moisture from penetrating the tyre carcass in amounts sufficient to cause damage to, or loss of cohesion of, the carcass components. 

The properties required of a liner to perform this function include the ability to adhere permanently to the tyre carcass, heat resistance, flexibility and flex crack resistance over the full operating temperature range and a low level of permeability to air and moisture. Regular butyl rubber cannot be used in this application except, in the form of butyl reclaim, as a flexible, highly impermeable filler for other elastomers, because it cannot be made to adhere strongly enough to the tyre carcass. Bromobutyl rubber possesses all the properties, in ample measure, required for premium quality inner liners, but a few parts of natural rubber are normally included in chlorobutyl liner stocks to ensure that they have adequate cured bond strength (see Tables 16 and 17). 

Heat ageing in the presence of air is often used to categorise rubber compounds. Natural rubber and high c/5-polyisoprenes are not particularly resistant to ageing temperatures above 70 ""C. For some applications, however, polyisoprene compounds may well exceed this temperature during their normal service life and often under dynamic conditions. This would be the case for compounds used in tyre carcass and for wire coat compounds where ingress of air or oxygen is limited. 

The characteristics of high c/ -polyisoprene compounds in anaerobic ageing conditions show improved aged property retention for certain types of formulations (see Section 7). Such compounds are particularly interesting in tyre carcass constructions where the ingress of air is minimal. Internal temperatures in heavy duty truck and bus tyres exceed the levels normally considered practical for either natural or synthetic polyisoprene. The retention of physical properties and the extended flex life of high cis-polyisoprene under these anaerobic conditions can be beneficial to the tyre constructer. 

A passenger tyre carcass formulation is shown in Table 45. In this application, adhesion to fibres is a consideration. The cure system suitable for this application is based on TBBS/MBTS/IS. 

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