Light Coloured Rubbers

MgC03 is used as a reinforcing filler for white and light-coloured rubber stocks. Certain types have almost the same refractive index as rubber and are therefore useful in making transparent and translucent vulcanisates. 

The most effective antioxidants for light coloured rubber compounds are the hindered bisphenols, but these offer little ozone and flex cracking resistance. 

Benzofuran derivatives and enolethers are offered as chemical antiozonants for light coloured rubber compounds. Benzofuran derivatives are used in CR and its blends with other rubbers and give ageing protection in addition to ozone protection. 

The production of light coloured products with a requirement for low build-up of static electricity requires the addition of an ingredient which is capable of providing the rubber with a low electrical resistance. Quartemary ammonium salts and ethylene oxide condensates provide one route. Of the common plasticisers, phosphate types have the lowest electrical resistance conferring properties in rubbers. Special antistatic plasticisers, such as polyethylene glycol fatty alcohol ethers, are designed to give rubbers with low surface resistivity. 

Colour of paint, chosen for exterior of rubber lined tanks can make a difference. A light colour will lower the temperature inside of the tank and a dark colour will radiate the heat especially in storage tanks. 

This is a white pigment used as a reinforcing filler (which is comparable in volume with zinc oxide) and it is also an excellent heat-resisting filler for silicone rubbers. The rutile form gives a rather creamier, more reflectant colour, which is more stable at high temperatures. They are widely used fillers in the manufacture of white or light colour chemical resistance compounds for the pigmentation industry. 

Chlorosulphonated polyethylene (CSM). A synthetic rubber produced by reacting polyethylene with chlorine and sulphur dioxide. Its products have good weather resistance even in light colours. Applications technical rubber goods, roofing sheets, fabric coatings, film-forming component in lacquers and paints. Trade name Hy-palon (USA). 

ADS rubbers can be considered a more sophisticated version of USS, which is crude and produced by smallholders. It is made in much the same way as RSS rubbers, except that it is dried without the smoke and at lower temperatures. As such it is very much lighter in colour than the RSS grades and may be used as pale crepe which has remained the preferred grade when extreme purity and very light colour product is required. It is prohibited to add the fungicide, paranitrophenol to ADS when the rubbers are used in products for food applications. ADS is normally sold as the best grade of RSS 1 or IX whereas technically specified ADS must meet the TSR 5 specifications. 

A more recent article that addressed the use of the DeLink process was published in Rubber Journal Asia [13]. It featured the Gujarat Reclaim and Rubber Products Company, which produces reclaimed rubber from both synthetic and NR waste, as well as a light-coloured reclaim from latex scrap using the Rubplast process. The company uses Green Rubber s patented devulcanisation agent, DeLink, at a ratio of two parts DeLink to 100 parts crumbed waste rubber, to produce a product that can be incorporated back into new rubber compounds. The article claims that this is very advantageous to the rubber industry as it enables them to re-use the 5-15% of waste, which they typically throw away. 

Whitings, talcs and soft clays enhance processing properties and are low in cost. Heat treating butyl rubbers with fine-particle precipitated silica, in the presence of a promoter, provides optimum reinforcement in light-coloured compounds provided that a small amount of diethylene or polyethylene glycol is included with the other compounding ingredients to minimise the tendency of silica to retard the cure. 

Change of colour of a vulcanised rubber when exposed to light or change of colour in a material in contact with, or adjacent to a vulcanised rubber. 

C60 fullerene (96 mg) was dissolved in toluene (150 mL) in a conical flask with rubber stopper. Zn powder (24 g) was added and then 20 mL of DC137%. Immediately after the addition of DC1, the flask was closed with the rubber stopper and hand-shaken. Periodically the stopper was slightly raised to permit to discharge the pressure of D2. After this treatment the solution changed its colour from violet to light orange. Then, other 10 mL of DC1 were added and the mixture shaken again in the closed flask. 

Vulcanite light Can fade to khaki Dulls with age Plasticy, warm Smooth Colour spots, surface dimples Moulded Bent/screwed Brown Rubber and sulphur... 

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