|Publication number||US3930063 A|
|Publication date||Dec 30, 1975|
|Filing date||Aug 23, 1973|
|Priority date||Aug 23, 1973|
|Publication number||US 3930063 A, US 3930063A, US-A-3930063, US3930063 A, US3930063A|
|Inventors||Richard C Miller, Charles C Payne|
|Original Assignee||Nalco Chemical Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Referenced by (34), Classifications (32)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Unite States atent Miller et al.
CORRECTING FOR NON-UNIFORMITY OF A SILICA SOL COATING Inventors: Richard C. Miller; Charles C.
Payne, both of Chicago, Ill.
Assignee: Nalco Chemical Company, Oak
Filed: Aug. 23, 1973 Appl. No.: 390,897
US. Cl 427/54; 73/150 R; 106/23; 106/36; 106/287 S; 427/157; 427/158 Int. Cl. BOSD 3/06; B05B 5/00; D061, 3/12 Field of Search 117/33.5 R, 169 A; 73/53, 73/150 R, 159; 250/321-323; 106/23, 36,
References Cited UNlTED STATES PATENTS 10/1950 Powers 117/169 A 51 Dec. 30, 1975 Primary Examiner-Michael R. Lusignan Attorney, Agent, or FirmKinzer, Plyer, Dorn & McEachran  ABSTRACT A large particle sized silica sol and a fluorescent dye are mixed together and applied as a coating to a substrate with theapplication monitored during coating by a light which renders the fluorescent dye visible; if the coating is blotched or uneven, corrections can be made during the run to provide a uniform coating.
2 Claims, No Drawings CORRECTING FOR NON-UNIFORIVIITY OF A SILICA SOL COATING BACKGROUND OF THE INVENTION This invention relates generally to coating of substrates with an antiskid material and more particularly concerns the coating of substrates with an antiskid material in the form of a silica aquasol, provision being made for observing the uniformity of the coating applied to the substrate.
It is quite common in coating applications to coat a substrate several times, often with a coating which is hard to see with human eye. While this is a common problem with a clear coating, it is also a problem when coatings of similar color to the substrate are made. Often in these coating operations the applicator becomes blocked causing a non-uniform coating to be applied and it is necessary to quickly discover that the application is not uniform so as to correct the applicator.
Some attempts to discover this have used an indicator spray which is sprayed on the coating and gives a characteristic color if the silica is presehtfHowever, these indicators have been confined to use on special test panels of the coated substrate which are run infrequently, usuallyat the'start up of the coating application and at spaced intervals to recheck. These indicator sprays cannot be applied to a wet coating due to the solvent incompatability, so the coated substrate must be at least partially dried before the indicator spray is usable. These indicator sprays also form a permanent color change which renders any sprayed coated substrate unusable, so the test panels are usually discarded.
Accordingly it is an object of this invention to provide a composition and method for easily observing the uniformity of application of a silica sol coating. Another object is to provide a means for observing the uniformity of an aqueous silica sol coating application while the coating is still wet. An allied object is to provide a composition and method for observing the uniformity of a silica coating on a substrate without rendering the substrate unusable. A related object is to develop a composition which meets the above objects and one which does not have any adverse effects on the antiskid coating.
SUMMARY OF THE INVENTION In accordance with the invention, a method for determining the uniformity of application of a silica aquasol coating on a substrate has been found which includes, preparing a liquid coating for application to the substrate and incorporating an indicator which becomes visible when irradiated with radiant energy of a predetermined wave length in the liquid coating. The coating and the indicator are then applied to the substrate and the applied coating is irradiated with the radiant energy of the predetermined wave length to render the indicator visible whereby any blotching or imperfections in application are readily apparent to a worker at an observation station. The applicator can be easily adjusted since the worker knows exactly when the problem occurs, and the imperfect coating on the substrate may be corrected by secondary applicators down the line from the observation station.
Other objects and advantages of the invention will become apparent from the following detailed description. While the invention will be described in connect-ion'with a preferred embodiment, it will be understood that his not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit andscope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION The preferred form of antiskid agent is that of an aqueous silica sol. Aqueous silica sols with particle diameters from 4 to 150 mu can be used; however, large particle size sols are preferred due to their excellent antiskid performance. The preferred range of particle diameters is from 50 to 150 mu. Of course, other antiskid compositions such as those based on aluminum oxide, other metal oxides or coated silica sols can also be used.
A preferred fluorescent dye is that of Calcofluor White ST, manufactured by American Cyanamid, but other fluorescent dyes can be used. The amount of dye added to the product should be low enough that the properties of the product and of the substrate are not adversely affected but large enough that the dye can be I seen on a substrate with the irridiating radiation. This level depends upon the particular dye chosen, the amount of dilution of the antiskid product and the long term stability of the product.
An ultraviolet light is a convenient source of irradiation.
The fluorescent dye is usually applied as a solution rather than a dry powder. It was found that very low fluorescence was observable on the substrate at equivalent levels of fluorescent dye in the powder form being added to the antiskid mixture. A fluorescent brightener is optionally added to the fluorescent dye solution. A preferred mixture is a fluorescent dye dissolved in water containing small amounts of cellosolve and triethanolamine and a fluorescent brightener to give a solution which contains approximately 30% by weight fluorescent material. The cellosolve and triethanolamine are present to facilitate the initial dissolution of the fluorescent dye in water. A preferred brightener is a sulfonated triazinylstilbene known as fluorescent brightener 28, Color Index No. 40622. Some of these brighteners are available from E. I.-Dupont and are known as Paper White BN, Paper White BP, Pontamine White BT and Pontamine White BTS.
A preferred antiskid and fluorescent dye coating was prepared consisting of approximately 40% silica concentration and a fluorescent dye concentration of 0.7%.
EXAMPLE 1 A silica sol solution containing 50% SiO having a pH of 8.5, a viscosity of 10 cps and an average particle size of to mu was diluted with water to a 42% silica level, and a dye solution containing 30% Calcofluor White ST dissolved in water containing small amounts of cellosolve and triethanolamine was added with an appropriate amount of water togive a final 40% silica level to the application mixture, and mixed. The final concentration of Calcofluor White ST was 0.7% with approximately 0.2% by weight active fluorescent material. It is usually necessary to mix the fluorescent dye with the water prior to addition to the silica sol in order to prevent formation of gel particles, but accelerated aging tests showed a stability of the mixture of greater than one year.
The mixture of Example 1 was applied to a cellulosic substrate by application means such as a sponge, felt,
roller, knife edge or sprayer. An operator can irradia'tethe coated substrate with ultraviolet light to determine if the applicator is working properly and applying a uniform coating to the entire substrate. Adjustments can be made on the applicator while the machine is running in order to correct any non-uniformity of application.
Antiskid tests were carried out on kraft wrapping paper coated with the above mixture containing a fluorescent dye and also the above mixture without a fluorescent dye. The slide angle was not adversely affected by the dye. Not only were completely uncoated areas easily observable, but also differences in thickness of the application were apparent from the intensity of the fluorescence.
When the prior art indicator sprays were used to check the coating levels, no difference was observed in the color and intensity of the separate indicator whether or not the coating contained a fluorescent dye. However, ultraviolet illumination of the substrate was capable of detecting the coating of antiskid agent at higher dilutions where the reaction of the indicator spray failed but the fluorescence was still present.
Thus, it is apparent that there has been provided, in accordance with the invention, a coating that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evi- 4 dent that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.
1. A method of determining the uniformity of application of a coating on a substrate and correcting for lack of uniformity comprising:
preparing an aqueous coating mixture containing an aqueous silica sol; incorporating in said coating mixture a fluorescent dye which becomes visible when irradiated with radiant energy of a predetermined wave length;
applying said coating mixture including said fluorescent dye to a substrate by means of an applicator;
radiating the applied coating on the substrate while it is still wet with radiant energy of said predetermined wave length to render the fluorescent dye visible to denote the uniformity or lack of uniformity of the application; and
adjusting the applicator to correct for non-uniformity of coating application.
2. A method as in claim I wherein said silica is about 40% of weight of the total coating mixture and said fluorescent dye is about 0.2% by weight of the total coating mixture.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2527329 *||Apr 14, 1945||Oct 24, 1950||Monsanto Chemicals||Method for producing slip-resistant textile materials|
|US2774886 *||Nov 19, 1952||Dec 18, 1956||Switzer Brothers Inc||Method of detecting surface discontinuities|
|US2935481 *||Apr 20, 1955||May 3, 1960||Monsanto Chemicals||Water-soluble fluorescent dye-coated hydrophobic silica and process of making the same|
|US2952192 *||Nov 24, 1954||Sep 13, 1960||Reliance Steel Prod Co||Marker stripe|
|US2983202 *||Oct 21, 1957||May 9, 1961||American Marietta Co||Highway marking paint|
|US3030870 *||Apr 9, 1957||Apr 24, 1962||Karl W Flocks||Marker|
|US3243875 *||Apr 1, 1964||Apr 5, 1966||Joseph Illo||Billet inspection apparatus and method|
|US3253146 *||Aug 16, 1962||May 24, 1966||Prismo Safety Corp||Fluorescent marker pigment for roadways|
|US3577885 *||Jul 30, 1969||May 11, 1971||Phillips Petroleum Co||Paper coating composition|
|US3754984 *||Feb 14, 1972||Aug 28, 1973||Nalco Chemical Co||Silica sol compositions and use for coating|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4281033 *||Mar 12, 1980||Jul 28, 1981||Magnaflux Corporation||Fluorescent penetrant system|
|US4307149 *||Nov 5, 1979||Dec 22, 1981||Columbia Ribbon & Carbon Mfg. Co., Inc.||Transfer elements and process for making same|
|US4396528 *||Jun 9, 1981||Aug 2, 1983||Varian Associates, Inc.||Fluorescent composition, a process for synthesizing the fluorescent composition|
|US4771862 *||Jan 22, 1988||Sep 20, 1988||Tufco Industries Inc.||Ladder guards|
|US4911830 *||May 26, 1988||Mar 27, 1990||Pms Consolidated||Fluorescent pigment concentrates|
|US4922113 *||Mar 7, 1988||May 1, 1990||Minnesota Mining And Manufacturing Company||Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor|
|US4978731 *||Feb 2, 1990||Dec 18, 1990||Minnesota Mining And Manufacturing Company||Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor|
|US4982603 *||Feb 3, 1989||Jan 8, 1991||Dow Corning Corporation||Quality assurance test utilizing an amino functional organosilicon optical brightener|
|US5047444 *||May 31, 1989||Sep 10, 1991||Minnesota Mining And Manufacturing Company||Fluorescent degree of cure monitors|
|US5087670 *||Oct 5, 1990||Feb 11, 1992||Minnesota Mining And Manufacturing Company||Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor|
|US5118559 *||Jun 3, 1991||Jun 2, 1992||Minnesota Mining And Manufacturing Company||Fluorescent degree of cure monitors|
|US5182316 *||Nov 26, 1991||Jan 26, 1993||Minnesota Mining And Manufacturing Company||Fluorescent degree of cure monitors|
|US5270116 *||Jun 5, 1991||Dec 14, 1993||Minnesota Mining And Manufacturing Company|
|US5310604 *||Aug 13, 1993||May 10, 1994||Minnesota Mining And Manufacturing Company||Composite structure for the fluorimetric monitoring of functional coatings|
|US5391414 *||Sep 21, 1992||Feb 21, 1995||Minnesota Mining And Manufacturing Company||Diskettes having crosslinked adhesive bond to hub|
|US5514479 *||Jun 5, 1995||May 7, 1996||Feldstein; Nathan||Functional coatings comprising light emitting particles|
|US5516591 *||Aug 25, 1994||May 14, 1996||Feldstein; Nathan||Composite plated articles having light-emitting properties|
|US6261631 *||Dec 22, 1999||Jul 17, 2001||Tnemec Company, Inc.||Method for controlling wet film thickness of clear coatings by means of color-dissipating dye|
|US6488719||May 10, 2001||Dec 3, 2002||Inemec Company, Inc.||Method for controlling wet film thickness of clear coatings by means of color-dissipating dye|
|US6630998||Aug 12, 1999||Oct 7, 2003||Acushnet Company||Apparatus and method for automated game ball inspection|
|US6682810||Mar 16, 2000||Jan 27, 2004||Heriot-Watt University||Fluorescent materials|
|US6809822||Nov 13, 2002||Oct 26, 2004||Acushnet Company||Apparatus and method for automated game ball inspection|
|US6825931||Mar 20, 2001||Nov 30, 2004||Acushnet Company||Apparatus and method for automated game ball inspection|
|US6839138||Nov 13, 2002||Jan 4, 2005||Acushnet Company||Apparatus and method for automated game ball inspection|
|US7079262||Aug 8, 2003||Jul 18, 2006||Heroit-Watt University||Fluorescent materials|
|US8697179 *||Sep 3, 2010||Apr 15, 2014||The Boeing Company||Colored coating and method|
|US20050037231 *||Aug 8, 2003||Feb 17, 2005||Jones Anita Claire||Fluorescent materials|
|US20070042139 *||Mar 6, 2006||Feb 22, 2007||Luminous Technologies Ltd.||Luminescent coating|
|US20080305244 *||Jun 8, 2007||Dec 11, 2008||Ji Cui||Monitoring a coating applied to a metal surface|
|US20100330264 *||Sep 3, 2010||Dec 30, 2010||The Boeing Company||Colored coating and method|
|DE102008033940B3 *||Jul 18, 2008||Jan 21, 2010||Innovent E.V.||Functional layer quality determining method, involves separately supplying colorant to working gas or plasma beam or flame or together with precursor, where method is implemented as normal pressure plasma method|
|DE102013223261A1 *||Nov 14, 2013||May 21, 2015||Bayerische Motoren Werke Aktiengesellschaft||Karosseriebeschichtung, Fahrzeug, Verfahren zur Ermittlung von Karosserieschäden an einem Fahrzeug und Verwendung einer Folie mit einem Fluoreszenzmittel|
|WO2008154155A2 *||May 27, 2008||Dec 18, 2008||Chemetall Corporation||Monitoring a coating applied to a metal surface|
|WO2008154155A3 *||May 27, 2008||Jan 29, 2009||Rodney H Banks||Monitoring a coating applied to a metal surface|
|U.S. Classification||427/9, 427/158, 252/301.16, 106/36, 427/557, 73/150.00R, 106/31.15, 106/287.35, 427/10, 252/965, 427/157, 427/553, 106/287.34, 252/408.1, 427/8|
|International Classification||G01N21/91, B05D3/06, C09D5/22, D21H21/30|
|Cooperative Classification||D21H21/30, D21H27/00, D21H5/0072, Y10S252/965, D21H19/40, G01N21/91, C09D5/22|
|European Classification||D21H27/00, D21H19/40, D21H5/00D, C09D5/22, G01N21/91, D21H21/30|