What is rubber roll?

The application of rubber to the surface of metal cores to make rubber covered rolls generally referred to as rubber roll. The function of rubber roll in various application are diverse, demanding different properties from the rubber that is used. One of the the most extensive uses of rubber roll is in the control liquids by pressing or squeezing, as exemplified in the manufacture of paper and in the processing of metal, textiles, plastics, and leather. Such typical device as the press roll, the touch roll, the padding roll and the transfering roll.

Rubber roll are used for many conveying purposes such as feed rools and guide rools of various kinds, as used in the paper steel textile and plastic industries. The properties of rubber that are important for such application include elasticity, friction abrasion resistance and chemical resistance . In advantage resistance to solvents and plasticizer as well as resistance to heat are desired in application such as laminating, embrossing and coating.

The design of rubber roll involves considering of general factor such as the work place, the working condition, the desire performance and the required durability. The core is designed on factors such as the load, the speed and the the required precision. The core may be built the seamless, welded or cast pipe and may be made from mild steel, cast iron, stainless steel etc. It is almost possible to vulcanize soft rubber satisfactorily to the cast iron core because during vulcanization heat drives gases out the porous iron causing blisters in the covering and resulting in early service failure. To overcome this problem a layer of ebonite is applied to the core and before the soft rubber cover.

How to design tires compound

Customers demand quality products. This will be as true in the feature as it is today. Tire are also designed to meet spectrum of service and enveronment condition. Aricraft and earthmover tires are the most advanced global tires that are specific for service, vehicle and enveronmental condition. The key properties to design tire tread compound is abrasion, heat buildup , wet grip and tear strength. Other properties that required is ease of processing. Different methods are used to develop the wide range of compounds required. Some compounds have ralatively simple application requirements, and some call for very complex properties that come close to the limits of materials and compounds. There for the same development process is not required for every compound. Some compounds are developed simply by making small changed in existing compound . Both tire technology and compound technology are changing as a result of trial and error, and intuition to become more scientific and predictive.

Rubber properties : Freezing

The effects of temperature so far described take place instantaneously with any change of temperature. There is , however at least with certain types of rubber including natural rubber, another effect which is produced by long exposure to moderately low temperature. This is a gradual hardening, often referred to as ‘freezing’ , due to the tendency of part of neighbouring molecules to line up in parallel ; this permits stronger intermolecular attractions which bind the parallel molecule segments into a more or less rigid ‘crytallite’ , to use a familiar, though not very accurate, name. This process is quite gradual and proceeds over periods of many days; it is most rapid at a particular temperature which in the case of natural rubber about –25 *C . Vulcanisation reduces, though it does not eliminate, this technically undesirable effect, which must be noted especially in connection with the storage of rubber articles. The change from rubber-like to glass-like properties occurs at a temperature called the glass transition temperarture. Certain other properties also change suddenly at this temperature, for instance, the coefficient of thermal expansion is less below the glass transition temperature, but rubber is never used in practice below this temperature. Another inportant consequence of the influence of temperature on deformation rate is that, broadly speaking, the behaviour of rubber is change in the same way either by increasing the rate of deformation or by lowering the temperature; conversely, reducing the deformation rate produces the same effect as raising the temperature. There is, in fact, a fundamental relationship between temperature and strain-rate effect.