Sealants

Post-treatment process withstands tarnish and protects against corrosion

Manufacturers of leather goods, jewelry, hardware and other consumer goods seek long-term protection for precious metal components: a treatment that is invisible, yet prevents oxidation and discoloration over a long service life. They also seek to limit the consumption of precious metals. With both objectives, the challenge is to do so without detracting from product appearance, feel and overall value perception.

Connectors, gromets, jewelry and hardware post-treated with Uyemura sealants

Sealing 691 and 692 is a post-treatment process that offers long-term protection for precious metal surfaces, respectively, for yellow and rose gold, silver, copper and tin. Sealing 691 and 692 permanently preserve metal brightness and luster on high-end jewelry, handles, rivets and other decorative metal components. They also seal thin gold's inherent porosity more effectively than alternatives.

Engineered nanopolymers absorb on the metal surface, crosslinking to form an invisible, undetectable layer. By penetrating the grain structure, it prevents oxidation of the underlying nickel or copper, so when gold is applied, plated parts exhibit high levels of corrosion resistance.

And while a layer of protection a few nanometers thick is what’s most often specified, the use of current allows the building of a layer many molecules thick where desirable.

Their proprietary organic molecule has a unique affinity for electrodeposition – and unrivaled process flexibility. Both processes have a short dwell time – as little as 4 seconds, compared to competitive products at 30 seconds or longer.

Global consumer goods manufacturers find that gold alone often fails to meet a high corrosion specification; Sealing 691 and 692 allow products to easily meet these standards.

Sealing 691 preserves metal’s inherent lubricity and leaves technical characteristics unaffected, so it has substantial advantages for electronic applications such as plug connectors. It can be used in rack or barrel equipment, and is particularly well-suited to reel-to-reel equipment.

Sealing 691 with Basic Additive is applied to enhance anti-tarnish protection. The coating reduces the friction coefficient, making it suitable for sliding and plug-in contacts, as well as for decorative applications; it has no adverse effects on solderability or contact resistance.

Sealing 616 protects silver against tarnishing; it is well suited for FDA applications.

Sealing 691 and 692 were developed by Umicore Galvanotechnik as improved versions of their popular Antitarnish 616 PLUS. They are available throughout North America exclusively from Uyemura. For more details, or to arrange test processing, email us or contact your Uyemura representative.

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