China produces quite a bit of white oils, but niche applications such as rubber seals require high-quality plasticizers formulated with hydrocracked white oils, which often must come from foreign sources.
China has many manufacturers of high-quality rubber seals used in technical applications in construction, automobile manufacturing and a variety of other industries. Plasticizers in rubber seals are often made with white oils, but Chinese seal suppliers often have to outsource the necessary cuts from foreign companies such as Nynas, said Chen Qian, general manager of Lian He Qiang Corp., a Shenzhen-based seal supplier.
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China doesnt lack white oil suppliers for the mass market, but does lack high-quality white oils for the niche market, Chen said at the White Oil Industry Summit held in Guangzhou in early December.
White oils – in the form of plasticizers – make up 25 to 35 percent of the composition of rubber seals, he added. Its safe to say that seal quality is closely related to white oil quality.
Chens company, for instance, mainly serves clients in the construction industry. To formulate rubber seals, Lian He Qiang procures high-viscosity white oil grades such as 300 neutral and 500N, which have kinematic viscosities falling between 90 and 100 centiStoke at 40 degrees Celsius.
For such products, Chinese white oils often arent up to snuff, Chen claimed. Chinese-made 500N white oil often turns yellowish when exposed to ultraviolet light, so we eventually chose a Korean supplier, whose oil showed much more stability under UV testing.
Some other applications require heavier grades, he noted, claiming that Chinese specialty product manufacturers will continue increasing demand for paraffin white oils that have viscosity above 100 cSt and both high viscosity index and high flash points (greater than 220 C).
Seal manufacturers are buying better [manufacturing] equipment to improve productivity, he continued. Faster processing speed means higher processing temperature. White oils containing impurities could cause severe smoke [pollution] under high-temperature processing, therefore they are no longer suitable for our industry, he said. Highly refined white oils are needed to comply with Chinas increasingly strict environmental laws, he continued.
White oils are used in a range of cosmetics and plastics – which together make up half of the global market – as well in various applications in the textiles, adhesives and pharmaceuticals industries. The food industry uses white oils as release agents and to formulate food-grade lubes. Other applications include textiles, agricultural sprays, fertilizers and defoamers.
All grades of base oils can be used to produce white oils, so choice of grade largely depends on regional availability. API Group II makes up the vast majority of white oil production, and Group I is the next most significant grade. Naphthenics come third and Group III products are used the least.