Lilly Industries, Inc.

Lilly Industrial Coatings, Inc.

Lilly Technologies, Inc.

Lilly London, Inc.

Joseph Soltys

Timothy J Sanford

Charles L Cesnik

An apparatus is provided for making mirrors having enhanced reflective layer resistance to corrosion. The reflective layer of the mirror, typically silver, is contacted, preferably simultaneously, with a first solution containing a specific cation and a second solution containing a specific anion, or alkaline material which forms hydroxyl ions, the specific cation and specific anion or hydroxyl ion reacting to form a water insoluble precipitate on the silver surface. The mirror may then be painted to provide additional corrosion resistance to the mirror. The apparatus device for forming the precipitate eliminates the need for a device to form a copper layer on the silver surface and the device may be incorporated into existing mirror production lines as a replacement for the copper layering device. Also provided are mirrors made using the apparatus of the invention. A preferred cation containing solution contains tin (e.g., SnCl ) and a preferred anion containing solution contains hydroxyl ions (e.g, NaOH).

Silver film incorporating protective insoluble metallic salt precipitate

A method is provided for making mirrors having enhanced reflective layer resistance to corrosion. The reflective layer of the mirror, typically silver, is contacted, preferably simultaneously, with a first solution containing a specific cation and a second solution containing a specific anion, or alkaline material which forms hydroxyl ions, the specific cation and specific anion or hydroxyl ion reacting to form a water insoluble precipitate on the silver surface. The mirror may then be painted to provide additional corrosion resistance to the mirror. The method eliminates the need for a copper layer on the silver surface and the method may be incorporated into existing mirror production lines as a replacement for the copper layering step. Also provided are an apparatus for making the mirrors and the mirrors made using the method and apparatus of the invention. A preferred cation containing solution contains tin (e.g., SnCl,) and a preferred anion containing solution contains hydroxyl ions (e.g., NaOH).

A method is provided for making mirrors having enhanced reflective layer resistance to corrosion. The reflective layer of the mirror, typically silver, is contacted, preferably simultaneously, with a first solution containing a specific cation and a second solution containing a specific anion, or alkaline material which forms hydroxyl ions, the specific cation and specific anion or hydroxyl ion reacting to form a water insoluble precipitate on the silver surface. The mirror may then be painted to provide additional corrosion resistance to the mirror. The method eliminates the need for a copper layer on the silver surface and the method may be incorporated into existing mirror production lines as a replacement for the copper layering step. Also provided are an apparatus for making the mirrors and the mirrors made using the method and apparatus of the invention. A preferred cation containing solution contains tin (e.g., SnCl.sub.2) and a preferred anion containing solution contains hydroxyl ions (e.g., NaOH).

An ammonia-free reducer is added to cupric ions to achieve reduction to cuprous hydroxide in a process for the deposition of metallic copper on a catalytically activated surface by rapidly reducing cupric ions in aqueous solution to cuprous hydroxide, without substantial reduction to elemental or metallic copper, and thereafter effecting controlled disproportionation of the resultant cuprous hydroxide to bring about the deposition of metallic copper. The ammonia-free reducer is preferably hydroxylamine or its salts in the presence of a water soluble alkali metal- or alkaline earth metal- hydroxide, more preferably sodium hydroxide. The process of reduction of cupric ions is further effected by adding to the solution an antiagglomerating agent for controlling the dispersion of the cuprous hydroxide, preferably a polyol such as sorbose or invert sugar. The process of disproportionation of the cuprous hydroxide is further effected by adding an activator comprising a hydroxycarboxylic acid or salt thereof, preferably citric acid or malic acid with sulfuric acid, to bring about the deposition of metallic copper principally on the catalytically activated surface, wherein the hydroxycarboxylic acid or salt activator is present in solution in an amount no greater than about one mole per mole of cuprous hydroxide.

Ammonia-free deposition of copper by disproportionation

A lead-free composition capable of being applied as a film and hardening to form a protective layer on the back of a mirror comprises a fluid organic resin and a corrosion inhibitor selected from the group consisting of dicyandiamide, metal or acid salts of dicyandiamide, hydrogen cyanamide, and 2-cyanoacetamide. The organic resin may be any thermoplastic or thermosetting resin suitable for coating the reflective and other metallic layers of the mirror. Exemplary resins include alkyd resins, acrylic resins, modified alkyd resins, polyesters, urethane oils, vinyl halide polymers or copolymers, oleoresinous varnishes, nitrocellulose compositions, phenol-formaldehyde resin varnishes, and epoxy resins. Preferably, the resin is an alkyd or modified alkyd resin. The aforementioned corrosion inhibitor may be present in an amount from about 0.1 to 20 weight percent, preferably 0.5 to 10 weight percent, of the organic resin coating system. The resin system should be essentially free of lead and lead salts. To inhibit the corrosion of metallic film layers on mirrors, a mirror having a glass substrate layer and a metallic film layer thereover should be obtained, after which the fluid organic resin coating system containing the aforementioned corrosion inhibitor is applied over the metallic film layer. The organic resin coating system is then hardened to produce the protective coating layer over the metallic layer. Other articles having metallic surfaces may also be protected by the resin system containing the novel corrosion inhibitor of the present invention.

Mirror back coating

A lead-free composition capable of being applied as a film and hardening to form a protective layer on the back of a mirror comprises a fluid organic resin and a corrosion inhibitor selected from the group consisting of dicyanadiamide, metal or acid salts of dicyandiamide, hydrogen cyanamide, and 2-cyanoacetamide. The organic resin may be any thermoplastic or thermosetting resin suitable for coating the reflective and other metallic layers of the mirror. Exemplary resins include alkyd resins, acrylic resins, modified alkyd resins, polyesters, urethane oils, vinyl halide polymers or copolymers, oleoresinous varnishes, nitrocellulose compositions, phenol-formaldehyde resin varnishes, and epoxy resins. Preferably, the resin is an alkyd or modified alkyd resin. The aforementioned corrosion inhibitor may be present in an amount from about 0.1 to 20 weight percent, preferably 0.5 to 10 weight percent, of the organic resin coating system. The resin system should be essentially free of lead and lead salts. To inhibit the corrosion of metallic film layers on mirrors, a mirror having a glass substrate layer and a metallic film layer thereover should be obtained, after which the fluid organic resin coating system containing the aforementioned corrosion inhibitor is aplied over the metallic film layer. The organic resin coating system is then hardened to produce the protective coating layer over the metallic layer. Other articles having metallic surfaces may also be protected by the resin system containing the novel corrosion inhibitor of the present invention.

Mirrorback coating

A lead-free composition capable of being applied as a film and hardening to form a protective layer on the back of a mirror comprises a fluid organic resin and a corrosion inhibitor selected from the group consisting of dicyandiamide, metal or acid salts of dicyandiamide, hydrogen cyanamide, and 2-cyanoacetamide. The organic resin may be any thermoplastic or thermosetting resin suitable for coating the reflective and other metallic layers of the mirror. Exemplary resins include alkyd resins, acrylic resin, modified alkyd resins, polyesters, urethane oils, vinyl halide polymers or copolymers, oleoresinous varnishes, nitrocellulose compositions, phenol-formaldehyde resin varnishes, and epoxy resins. Preferably, the resin is an alkyd or modified alkyd resin. The aforementioned corrosion inhibitor may be present in an amount from about 0.1 to 20 weight percent, preferably 0.5 to 10 weight percent, of the organic resin coating system. The resin system should be essentially free of lead and lead salts. To inhibit the corrosion of metallic film layers on mirrors, a mirror having a glass substrate layer and a metallic film layer thereover should be obtained, after which the fluid organic resin coating system containing the aforementioned corrosion inhibitor is applied over the metallic film layer. The organic resin coating system is then hardened to produce the protective coating layer over the metallic layer. Other articles having metallic surfaces may also be protected by the resin system containing the novel corrosion inhibitor of the present invention.

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London, Canada

Joseph Soltys