Uncured Rubber Compounds

In the rubber industry tackiness means the ability of uncured rubber compounds to stick together under moderate pressure. Tackifiers improve adhesion and joint... 

A piece of uncured rubber compound of suitable shape and volume to fill the cavity of the mould in which it is to be vulcanised also termed a slug . 

A compounding ingredient which enhances the surface tack of uncured rubber compounds. Tackifiers, exemplified by pine tar are classed under softeners and processing aids . 

The property possessed by certain colloids of forming a gel-like structure on standing but which revert to a liquid form when subjected to agitation. The term has also been applied to the stiffening effect shown by uncured rubber compounds containing fillers, particularly carbon black. 

Stitching - A method of joining two pieces of uncured rubber compound together by means of a stitching roller, and a hand held tool comprised of a wheel with a narrow edge which is often serrated. It is commonly used to make tank lining joints. 

Stock - An uncured rubber compound of a definite composition from which a given article is manufactured. 

These feedstocks were tested in a number of carbon black furnace reactors employing different geometries and different operating conditions. The experiments were designed to develop data for correlation between feedstock composition, yield, production rate, and properties of carbon black produced. The physical properties of the carbon blacks were measured as were the properties of uncured rubber compounds and vulcanizates in standard test recipes. 

Transfer moulding In transfer moulding the uncured rubber compound is transferred from the loading chamber (pot) of the transfer mould into the actual mould cavity. This technique is suitable for moulding products of a complicated shape, and for anchoring delicate inserts in mouldings. 

There are no standard ISO or ASTM test methods presently available for measuring tack or stick properties of an uncured rubber compound. Many rubber companies measure this property by their own proprietary methods. However, Momsanto Instruments Group introduced an instrument called the Tel-Tak Tackmeter in 1969 for measuring tack for tire and/or conveyor belt compounds. 

Lattimer, R. R, Harris, R. E., Rhee, C. K., and Schulten, H.-R., Identification of organic compounds in uncured rubber compounds using mass spectrometry. Rubber Chem. Technol, 61, 639, 1988. 

One of the unique properties of ZnO is its ability to retain the tack of uncured rubber compounds over many months of shelf-storage for adhesive tapes. 

Warm-up A milling operation to plasticize uncured rubber compounds before calendering, extruding, or molding. 

The filler localization experimentally determined by the use of our wetting concept is correlated to the wetting behaviour of rubber as follows the more the filler surface is wetted by a rubber phase, the more the filler is included and distributed in this phase. When filler is mixed with a single rubber, for instance SBR, a part of the rubber chains will be bonded to the active centres, which are available on the filler surface. If the rubber is extracted from the filled uncured rubber compound with a suitable solvent, the rubber molecules bound on the filler surface remain in the rubber-filler gel. In our concept, we are interested in the fraction of rubber in this rubber-filler gel. The wetting... 

Uncured rubber compounds, aged in the laboratory or external atmosphere, exposed to ozone or UV radiation including sunlight, suffer a reduction in their subsequent cured... 

A further technique is to form an adhesive strip containing the metallic coagent. The adhesive strip may then be used to bond another rubber to a metal surface. When the adhesive strip approach is used, the metallic coagents are milled into the rubber compoimd. The uncured compound is then formed into sheets by calendaring and then cut into stable, thin strips that contain the metallic coagent, peroxide and other rubber additives. The rubber strip can then be applied between the uncured rubber compound and the... 

Some details of the equipment are illustrated by Fig. 16. The upper die can be raised to separate it from the lower die. A sample of uncured rubber compound can be then introduced and the upper die lowered into place as in the illustration. In this work, the dies were first heated and controlled at an elevated temperature (e.g., 90°C), then the temperature of the dies and sample can then be quite rapidly changed to a desired temperature for testing or for vulcanizing the sample. The sample can be introduced at one temperature, measurements of dynamic mechanical properties (e.g., storage shear modulus G and loss shear modulus G ) can then be made at the same temperature or at another temperature. Then, if desired the sample can be heated to a vulcanization temperature and vulcanized (with the recording of a cure curve, i.e., modulus versus time) and then the temperature can be changed and dynamic mechanical properties can then be measured again. 

Barres C, Leblanc JL (2000) Recent developments in shear rheometry of uncured rubber compounds. I. Design, construction and validation of a sliding cylinder rheometer. Polym... 

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