Aminoplast resin photochromic coating from PPG. (Patent Update).* Patent No. U.S. 6,506,488 B1 PPG Industries PPG Industries (NYSE: PPG) was founded in 1883 as the Pittsburgh Plate Glass Company. PPG is an American manufacturer of glass and chemical products, including automotive safety glass. has obtained a patent for an article comprising, in combination, a substrate The base layer of a structure such as a chip, multichip module (MCM), printed circuit board or disk platter. Silicon is the most widely used substrate for chips. Fiberglass (FR4) is mostly used for printed circuit boards, and ceramic is used for MCMs. and a cured photochromic Pho`to`chro´mic a. 1. Of or pertaining to photochromy; produced by photochromy. aminoplast resin coating on at least one surface of the substrate, the coating being prepared by combining components comprising molecules having at least 2 hydroxyl groups hydroxyl group (hīdrŏk`sĭl), in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by a single bond to an alkyl group or aryl group. per molecule; aminoplast component comprising molecules having at least two reactive groups per molecule; and a photochromic amount of photochromic component. This is provided that the components are combined without reacting the components before combining, the cured coating being substantially free of cosmetic defects, the components being used in such proportions to produce a photochromic aminoplast resin coating having a Fischer microhardness of at least 45 to 180 Newtons per [mm.sup.2] as measured with a Fischerscope H-100 using a 100 milli Newton load, 30 load steps and 0.5 second pauses and exhibiting a [DELTA]OD of at least 0.15 after 30 seconds and at least 0.47 after eight minutes, and a bleach bleach Solid or liquid chemical compound used to whiten or remove the natural colour of fibres, yarns, paper, and textile fabrics. Sunlight was the chief bleaching agent up to the discovery of chlorine in 1774 by Karl Wilhelm Scheele (b. 1742—d. rate of not more than 180 seconds--all as measured in the 85[degrees] F photochromic performance test. |
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