Inside an automobile, a large number of seals and other elastomeric components are in constant contact with engine oil. At the high temperatures that necessarily develop during operation, substances arise in the oil that attack seal materials and result in chemical degradation. Hence, conventional elastomers are generally unsuitable for these types of applications, as they would gradually soften and lose their elasticity.
With the introduction of ELASTOSIL® LR 3016/65, WACKER now offers a liquid silicone rubber that does a better job of standing up to hot motor oil than previous silicones. The product is formulated in such a way that it reliably counters aggressive components of the oil. Fillers and additives contribute both to excellent long-term oil resistance and to very good mechanical properties in parts molded from ELASTOSIL® LR 3016/65.
Laboratory tests have shown that parts molded from the new liquid silicone rubber meet important specifications set down by car manufacturers. Properties such as hardness, elongation at break, tensile strength and tear strength are in full compliance with standards, even after several weeks of storage in motor oil kept at 150 degrees Celsius. Current specifications for seal materials, for example, call for a tear strength of at least 2 N/mm before or 1.5 N/mm after storage in hot motor oil (according to ISO 34-1 A). The tear strength of molded parts made of ELASTOSIL® LR 3016/65 before and after the oil storage test is 13 N/mm and 12 N/mm respectively, which is well within established standards.
The Shore A hardness value for cured rubber products made of ELASTOSIL® LR 3016/65 is 65. As an extremely fast-curing grade of liquid silicone rubber with good flow properties, this product allows manufacturers to cost-effectively make oil-resistant molded parts via injection molding on an industrial scale. Even small parts with delicate structures can be produced with a high level of precision and virtually error free.
Visit WACKER at K 2016 in Hall 6, Booth A10.