The compound development work, said Uneken, started with the limited set of ingredients allowed under the Elastomerleitlinie, while also taking account of the various production technologies used to manufacture seals and other rubber parts.
“There are, for instance, obvious differences between injection and compression moulding,” explained the Polycomp boss. “A complicating factor is that the use of plasticisers and processing aids is hardly, if not at all, possible when limits on microbial growth on non-metallic materials in contact with drinking water have to be met [under W270].”
The development finally resulted in two different compounds with different cure speeds. Polycomp, said Uneken, is targeting these compounds at applications including seals, pumps, valves and fittings for a range of sectors, including the food and pharmaceutical industries.
“In the food and pharma industries, requirements are increasingly stringent and the reliability of the parts in the applications is sometimes literally vital,” the managing director stated.
Blackburn, UK-based Silicone Engineering supplies solid and sponge sheeting and extrusions such as tubes, cords and profiles for use in the dairy and food & beverage industries. It has around 130 employees, a turnover of £16 million (E22.5 million). Much of its products are sold to EU markets – Germany in particular.
According to Simon Holmes, marketing manager, there is increasing market demand for silicone formulas that meet industry standards covering in applications such as food machinery, brewery tubes, food transfer tubes and baking mats.
“In the dairy market, for instance, chemicals have to be run through tubes to break down the fat residue and those chemicals can break down organic rubber easily,” said Holmes. “The same goes with heat – food industry needs a lot of heat and the amount of volatiles is a lot less in silicones, making them more heat-tolerable.”
Holmes is aware of the moves by the European Commission to assess the safety of food-contact rubber materials. However, he said, feedback from suppliers – mostly European – has indicated that his company’s products will most likely be unaffected by any new regulation.
He said all of Silicone Engineering‘s general purpose (GP) solid silicone range is FDA-compliant, adding that the company also holds BfR (German food accreditation) and WRAS (water regulation) for its GP solid silicone materials.
Among the company’s recent developments for the food industry is a solid silicone containing a silver ion additive that actively prevents the growth of harmful bacteria such as salmonella, E-Coli and MRSA.
The anti-bacterial material, said Holmes, can be used, for example, as gaskets and seals in food production machinery, food/beverage transfer tubes. It is also [used] as dairy tubing as it has been “independently proven to reduce milk bacto-scan results carried out on a dairy farm.”
Meanwhile, Silicone Engineering has also addressed issues around the additives used in silicone sponge, which conventionally make it difficult to get products approved by the FDA for food contact.