Rubber compounding activators

A non-sulphur vulcanising agent of particular application in butyl rubber compounds, the activator being red lead. 

A rubber to fabric bonding system comprising resorcinol, a formaldehyde donor and a hydrated silica filler. Incorporated as dry ingredients in the rubber compound and activated by heat. 

C17H35COOH, one of the fatty acids found in animal fats. Commercial stearic acid is a mixture of stearic and palmitic acids. It is used in rubber compounding as an organic activator of accelerators. 

An activator in rubber compounds containing organic accelerators. In polychloroprene, zinc oxide is considered to be the accelerator rather than the activator. The use of zinc oxide as a reinforcing agent and as a white colouring agent is obsolescent. Zinc oxide is manufactured by either the French (or indirect) process or by the American (or direct) process. It can be used as a filler to impart high thermal conductivity. 

Resorcinol formaldehyde latex (RFL) cord dips have only a limited application within the general rubber goods industry and for adhesion to be achieved with synthetic fibres it is necessary to use the systems developed by Bayer and Degussa. These systems are based upon a combination of resorcinol, a formaldehyde donor and a hydrated silica filler (commonly called the RFK system). This system is incorporated as dry ingredients into the rubber compound and is activated by the application of heat. 

Sulphur vulcanisation of rubber is catalysed by the presence of alkali materials. This activation of the vulcanisation system can result in unwanted short scorch times. The addition of weak acids to the rubber compound results in retardation of the crosslinking mechanism. The common materials used for retardation are... 

Many rubber compounds have a tendency to stick in the mould cavity after vulcanisation and require some type of mould release agent. The substances used are surface-active materials such as detergents, soaps, wetting agents, silicone emulsions, aqueous dispersions of talc, mica and fatty acids, applied by spray or brush. Alternatively, dry types based on polytetrafluoroethylene or polyethylene, usually carried in a solvent, can be aerosol applied. An alternative is the addition of an incompatible material to the rubber compound which will bleed to the rubber surface during vulcanisation. 

Modem designs fitted with non-retum valves through which the plasticised rubber compound passes into the injection cylinder portion are capable of giving precise shot volume. The non-retum valve is activated by the injection pressure. The injection ram/non-retum valve unit ensures complete purging of the injection chamber. 

Scofield s calculated X-ray photoionization cross sections, 24 86-87 Scoping activities, EIA, 20 234 Scoping methods, EIA, 20 239t Scopolamine, 2 79, 80 Scopolanine hydrobromide, 4 360t Scorch behavior, in rubber compounding, 22 794... 

Activator-A chemical used in rubber compounding in small quantities to increase the effectiveness of an accelerator. 

Methylphenyldimethoxysilane is used as a stabiliser (antistructuring additive) in the production of rubber compounds based on silicone elastomers and highly active fillers. Introducing up to 10% (weight) of methylphenyldimethoxysilane into a rubber mixture improves the physicochemical properties of vulcanised rubbers and helps to preserve the technological characteristics of the compounds in storage. 

Silicone elastomer-based rubber compounds are prepared in conventional apparatuses (closed agitators, roll mills, etc.) and consist of the following ingredients elastomer, active fillers, vulcanising agent, stabiliser, pigment additives. 

Extensive studies on different rubber compounds (see, for example, Table 1 in [105]) yield Ec 0.05 to 0.15 eV per filler-filler bond [105,106], i.e., typical values for physical (van der Waals like) bonds. Similar values were obtained within an approach which assumes a hypothetical analogy between the structure of a statistical carbon black network and that of a Gaussian elastomeric (unfilled) polymer network [107]. As in the Kraus approach, the carbon black network scission process is assumed to be thermally activated. 

Dispersing agent and accelerator activator in rubber compounds. It aids dispersion of pigments and fillers and improves processing since it acts as a stock lubricant and can facilitate mold flow, improve extrusions and aid release. 

Use Chemicals, especially stearates and stearate driers lubricants soaps pharmaceuticals and cosmetics accelerator activator dispersing agent and softener in rubber compounds shoe and metal polishes coatings food packaging suppositories and ointments. 

Use Paints, varnishes, rubber compounding (softener and activator). 

Bound rubber is the fraction of polymer which is not extracted by a good solvent from a rubber-filler mix. It is a measure of rubber reinforcement as well as of filler activity towards the rubber. This concept was introduced in 1925 by Twiss. Although, the traditional term bound rubber is commonly used for rubber compounds, the concept can also be applied to other macromolecular materials. The amount of bound rubber is given by the following equations ... 

Acrylic acid, zinc salt Ageflex ZDA EINECS 238-692-3 2-Propenoic acid, zinc salt Zinc acrylate Zinc dlacrylate. Crosslinker for molded polybutadiene compounds, conductive and protective coatings, coagent for SBR compounds and reactive pigments activator for rubber compounding scorch retarder. Rit-Chem. 

If the values of the cure enthalpy are pretty well given for several varieties of rubber compounds, the values of the energy of activation are not shown. An interesting apparatus was built and successfully tested for measuring the thermal conductivity of various rubbers with or without fillers. 

Rather than look for a mwe accnrate method for obtaining data for the kinetics of cure, attention was given to evaluating the effect of the lack of accuracy in the kinetic parameters. Some studies were conducted by using calorimetry [13-15]. Thus, the effect of the order of the overall cure reaction on the rate of cure was determined, and profiles of temperature and state of cure were evaluated by varying the value of the rubber compound cured with 3% sulfur [13]. By using the same approach and the same method, the effect of a variation of the activation energy on the profiles of tanperature and of state of cure was also studied [14,15]. 

On the other hand, when different rubber compounds are cured together, as seen with the components of a tire made of rubber In various compositions, a diffusion of the active agent, at least at the interface, is of great interest, as it makes the binding of these components more efQdent. As shown in Section 7.3, it is possible to increase and control this diffusion phenomenon. 

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