TRANSPARENCY WITH COATING HAVING PRIMER FOR EDGE SEAL

Abstract: Monolithic or laminated transparencies with a coating positioned on or over the transparency or within the laminate of transparencies having an edge sealant to protect the coating from corrosion by the environment. The composition for the edge sealant is applied on the peripheral lateral sides of the transparency and optionally along the peripheral marginal sides of at least one major surface of the transparency to function as a primer for adhesive attachment to a frame. The edge sealant seals the edge of the transparency with the coating to prevent coating degradation is from a composition selected from automotive clear coat coating compositions and/or organosilanes, and/or organotitanates and/or organozirconium compounds and/or adhesive primers.

Description: TRANSPARENCY WITH COATING HAVING PRIMER FOR EDGE SEAL * This application claims the benefit of U.S. Provisional Application No. 60/094,800, filed July 31, 1998, entitled, "Windshield With Coating having Primer For Edge Seal". The present invention is directed to monolithic or laminated plies of glass and/or plastic where one or more of the plies has one or more film coatings on or over one or more plies or between plies and a material as an edge sealant which optionally is also the adhesive primer. TECHNICAL DISCUSSION Glass and/or plastic laminates useful as transparencies such as vehicle windshields have been affixed to an opening such as an automotive body through the use of various chemical compositions. Usually an adhesive primer is placed on the marginal peripheral outer surface of the inner layer of the transparency. Also an adhesive composition is applied over the primer and the transparency is affixed to the frame or rim of the opening of the automotive body. For various laminates of glass and/or plastics edge sealing chemical compositions have been applied to seal the width or height edges of the transparency. This edge is the vertical edge when the transparency has its longitudinal axis in a horizontal position. Such edge sealing compositions like poly (vinylidenefluoride) and the like for use with coated transparencies such as windshields are disclosed in U.S. Patent No. 5,122,403 (Roginski et al.) As noted in U.S. Patent No. 5,122,403, windshields can have coatings for various purposes such as to make heatable windshields or to reduce infrared ("IR") and/or ultraviolet ("UV") radiation from passing through the transparency. These coatings can be applied within the transparency on an inner major surface as to the transparency of the outer plies of glass or plastic or on the inner or outer major surfaces of any interlayer plies. With this * application of these coatings, the approach of the coating to or at the vertical edge of the transparency can provide a source or conduit for environmental conditions. For instance, the coating can itself be corroded at the edge or provide for corrosion from acid rain or road salt finding its way from the vertical edge of the transparency into the laminated transparency. As noted in the 03 patent, hereby incorporated by reference, edge sealants have been used to protect an exposed edge portion of the coating from such degradation. Such an edge sealant is a weather resistant material that can adhere to the glass and interlayer material and will not react adversely with the glass, interlayer material, or coating of the transparency or an adhesive used to secure the transparency in place. The object of the present invention is to provide a material that provides both a glass primer for adhesive attaching of the transparency to a frame or rim of an opening and a edge sealant to reduce degradation or corrosion of the coating of a coated transparency from seepage or penetration of the vertical edge of the transparency. SUMMARY OF THE INVENTION The present invention is directed to a monolithic or laminated transparency or glazing having one or more coatings on one or plies of the transparency or glazing. The transparency has one or more coatings and/or films on, over or near an outer ply or between the outer plies of the transparency on either the inner major surface of one or more of the outer plies or on a major surface of one or more inner plies located between the outer plies. Some of these types of coatings may be susceptible to degradation or corrosion from environmental conditions, factors, or forces such as salt solutions and/or high humidity and/or acid rain and/or high frequency of thermal variations between hot and cold temperatures. The sealing is provided from the presence of at* least one edge sealant or in other words sealing coating layer of automotive clear coat coating compositions and/or organosilanes, and/or organotitanates and/or organozirconium compounds and/or adhesive primers over the environmentally susceptible coating where the environmentally susceptible coating is exposed to the environment. For a laminated transparency like windshields and other automotive windows or lites the edge sealant is applied on the vertical or lateral edge where the plies of the transparent material and the coating can be exposed to the environment. The application is on sufficient amount of surface area of the vertical edge or side of the transparency to seal the environmentally -susceptible coating or film in the transparency to retard deterioration of such a coating or film. Optionally, the edge sealant can also act as an adhesive primer on the marginal edge portions of the major outer surface of the transparency for attachment of the transparency to a support to act as a glazing to cover an opening. Such adhesive primer type of edge sealant include those that prime the glass or plastic for adhesion to a substrate, that are compatible with adhesives used for affixing the transparency to the support, and that do not themselves degrade the coating of the transparency to any great extent. Nonexclusive examples of such adhesive primers include polyurethane and/or organosilane containing chemical compositions. This edge sealant coating is one that preferably is essentially free of polybutene copolymer, fluoropolymer and butyl based compositions in a predominant amount of the adhesive primer/sealer composition. These types of polymeric materials are not necessary since the adhesive primer itself or the other types of edge sealants of the invention provides for edge sealing when disposed over the lateral edge of the transparency. BRIEF DESCRIPTION OF THE DRAWINGS * Figure 1 is a plan view of a laminated transparency highlighting the marginal peripheral surface having the edge sealant that is also present as the adhesive primer. Figure 2 is a view taken along line 2-2 of Fig. 1 with the view to show the edge sealant along the lateral or vertical edge and on the marginal peripheral surface of the inner layer of the transparency. Figure 3 is a side view of the top section of a laminated transparency with a top lateral edge having the edge sealant where the transparency can be used as an automotive sidelite . Figure 4 is similar to Figure 2 showing an 'alternative embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION The description of the invention is taught in connection with a laminated transparency comprised of two glass plies bonded together by an interlayer of plastic, which represents a typical windshield construction. Although it should be understood that the invention can apply to transparencies having two plastic plies or any combination involving numerous glass and/or plastic plies or a single (monolithic) ply of glass or plastic. For instance two polycarbonate plies could be laminated together with or without one or more layers of interlayer and these could serve as the laminate suitable for edge sealing by the present invention. The invention is not limited to an automotive windshield but may be used in any transparency where there is a problem of coating degradation along the exposed edge. For instance the laminated transparency could be a laminated automotive sidelite or even an automotive sunroof or even a skylight for commercial or residential construction. Also the ply or plies of a monolithic or laminated structure that are glass can be annealed as for example with windshields or tempered or heat strengthened, i.e. partially tempered, as for example sidelites. Suitable examples of transparencies that * have glass include such glasses as clear glass, float glass, clear or tinted float glass of suitable compositions to enable their production but preferably all of these have a base glass which is a soda lime type of glass with different colorant portions . In Figures 1-3 the same numeric references are used for similar components shown in the figures. Figures ("Figs.") 1, 2, and 3 show a transparency 20, which is substantially transparent, and which includes an inboard or inner glass sheet or ply 26, a plastic interlayer 24 and an outboard glass sheet or ply 22. Non-exclusive examples of glass suitable for plies 22 and 26 are described in U.S. -Patent Nos. 4,746,347; 4,792,536; 5,240,886; 5,385,872; and 5,393,593, which are all herein incorporated by reference. Interlayer 24 may be at least one layer of polyvinyl butyral as is commonly used for laminated windshields or any other suitable interlayer material known in the art. Suitable examples of the latter are disclosed in U.S. Patent No. 4,704,174, hereby incorporated by reference. For instance the poly (vinylbutyral) interlayers typically can have other polymeric materials like polyurethane and/or plasticizers and/or adhesion promoters like silane coupling agents such as vinyl triethoxy silane (VTES) as more fully described in U.S. Patent No. 5,028,658 hereby incorporated by reference. Other additives that may optionally be present include: dyes, ultraviolet light stabilizers, adhesion control salts, antioxidants, and treatments from additives to improve laminating efficiency as also noted in U.S. Patent No. 4,292,372, hereby incorporated by reference. Also multilayered interlayers can be used where between the layers there is one or more film layers of polyester or similar polymers . A coating 28 is preferably placed on a surface of the transparency 20 that is not exposed, most preferably on the inboard surface of the outboard glass sheet 22. Also with the present invention it is possible to place the coating on £ monolithic transparency and coat the functional type of coating with the edge sealant over the entire exposed surface of the functional coating 28. Various coating configurations may be applied as 28 to the major surface 30 depending on the desired properties to be added to the transparency 20. The coating can be of one or more films in one or more layers including use of existing film material such as polymeric based films with or without additional coatings. The latter is as opposed to forming a coating or film on the glass from one or more film forming compositions placed on the glass. The one or more coating film(s) can be those that function to provide solar control properties, optical properties, electroconductive properties, semiconductor properties, aesthetic properties, and the like known to those skilled in the art. The films of the coating can be applied over the substrate as thin films such as those applied by pyrolytic application, chemical vapor deposition, and sputtering techniques such as magnetron sputtered vacuum deposition (hereinafter "MSVD") or electron beam (EB) deposition. Any of these techniques that are well known to those skilled in the art can be used. For example, although not limiting in the present invention, suitable electroconductive coatings that are useful are those similar to the coatings and films disclosed in U.S. Patent Nos. 5,122,403 (Roginski et. al . ) and 4,610,771 (Gillery) which are hereby incorporated by reference. These patents disclose coatings to reflect IR radiation and/or provide an electroconductive film for a heatable windshield. These coatings generally include one or more silver films between pairs of zinc stannate films, each of which may be applied sequentially by magnetron sputtering. An optional opaque border 32 (shown only in Fig. 2), such as a ceramic enamel, may be applied about the marginal edge of the transparency 20 in any well known manner, e.g. screen printing and the like, and heated to bond the border 32 to surface 30. For instance a suitable opaque material is black frit layer or coating like a ceramic frit layer that * covers and conceals at least a portion of the inner surface 30. The area or pattern of the inner surface 30 which receives opaque coating 32 will generally include a region from peripheral edge 36 of the transparency inward. The inward distance can be around two or more inches or a sufficient distance to conceal from the exterior any edge sealant that also functions as an adhesive primer and forming the edge sealant as adhesive material for attaching transparency 20 to the vehicle. The ceramic frit coating 32 includes a pigment of a desired color, preferably a dark tint such as black or the like. One ceramic material used to form the opaque black, ceramic frit coating 32 is manufactured by 'Cerdec Corporation-Drakenfeld Products located in Washington, Pennsylvania. This is an example of the meaning that the transparency is substantially transparent, that is a major portion of the transparency for a vision area is transparent but other portions of the transparency may have coatings so that a portion or portions are not transparent or completely transparent. Another example is that transparencies other than those that are windshields and front side lites or panels for motor vehicles which are required by law to have a minimum luminous light transmittance value (LTA) can be darker as in privacy glass. Such privacy transparencies as used for rear lites and rear side lites on trucks and vans are still substantially transparent even though some of them may have very dark tints and/or coatings. In Figs. 1 and 2 after coating 28, the interlayer 24 as one or more layers is positioned between the bent glass sheets 22 and 26 and the entire assembly is laminated in any convenient manner well known in the art to form a unitary structure. As an alternative, the coating 28 may be applied to a flat glass ply 22 which is subsequently bent to a desired configuration . For the surface of the inboard ply of glass in the laminate that is to be affixed to the support, an edge sealant 34 (as shown in Fig. 2) is applied along the marginal * peripheral surface 35 (as shown in Fig. 1) and to as much of and preferably all of the peripheral lateral or vertical edge 36 of the laminated transparency 20. In this manner coating 28 serves as an edge sealant to hermetically seal exposed edge 38 and isolate it from the environmental at least at the time of manufacture and for a suitable use period thereafter. Otherwise for the present invention where the edge sealing coating will not be used as the adhesion primer or where the glazing of the transparency does not include an adhesive attachment, the edge sealant 34 is present on most preferably all of the lateral surface 36 of the transparency. However the sealant may not extend, but preferably does extend, to the 'peripheral marginal portion of the major surface of the transparency as at 35. Fig. 3 shows a laminated transparency as an automotive sidelite 20 including a first ply 22 having an outer major surface 23 and an inner major surface 30, a functional coating 28 deposited on, over or formed on at least a portion of the major surface 30, an interlayer 24 and a second ply 26 having an inner major surface 25 and an outer major surface 29. Usually the outer major surface 23 faces the exterior of the vehicle, and the outer major surface 29 faces the interior of the vehicle. The first and second plies 22 and 26, respectively, are each preferably made of a substantially transparent or translucent material, as noted above for Figs. 1 and 2. For sidelites, the thickness of the first and second plies are preferably less than about 3.0 mm, more preferably less than about 2.1 mm and even more preferably in the thickness range of about 1.6 - 1.8 mm. The edge sealant 34 results from the edge sealant composition applied to the top lateral edge 36. In addition the edge sealant composition can be placed or formed on the other lateral edges of the sidelite (not shown in Fig. 3), i.e., the sides and the bottom as the transparency 20 is positioned in the glazing. The edge sealant whether or not it has the * capability to function as both adhesion primer and edge sealant can be a one or two component application. The primer compounds generally include organosilanes and amino silanes such as those available from Dow Coming, Essex Specialty Products Inc., General Electric, and Lord Chemlock, and polyurethane-containing and/or automotive aqueous-borne or solvent-borne clearcoat compositions. Suitable examples include diamino-tri-methoxy silanes available under the designations Lord Chemlock 134/144. Adhesion primers, such as the adhesion promoters described in U.S. Patent Nos. 4,839,122 and 4,761,916, hereby incorporated by reference, can be used. Useful commercial materials include "Betaseal® Glass Primer ' 435.18", "Betaseal© Glass Primer 435.20A" and "Betaseal® Glass Primer 435.21", produced by Essex Specialty Products, Inc., Auburn Hills, Michigan. Other useful edge sealants which optionally also are adhesion primers include polyurethane compositions of U.S. Patent No. 5,623,044, hereby incorporated by reference, comprising (1) a urethane prepolymer having an isocyanate functionality of at least about 2.0 and a molecular weight of at least about 2,000; and (2) the reaction product of a secondary amino- or mercaptoalkoxy silane and a polyisocyanate having an average of at least one silane group and at least one isocyanate group per molecule and a molecular weight of less than about 2,000. Other silanes not limited to diamino or tri-methoxy forms may also be suitable. A second group of edge sealing coatings and optionally adhesion primers are organotitanates or zirconium coupling agents such as available from Kenrich Petrochemical Inc. of Bayon, NJ. Such coupling agents as with the organosilanes have the capability of reacting with organic compounds and inorganic materials including compounds and surfaces such as glass and the like. Generally these coupling agents have moieties for reaction with organic compounds and moieties for reaction with inorganic materials. Alternatively, or in addition to an adhesion primei*, one or more primers or single-component urethane adhesives may be used as the edge sealant and primer. Nonexclusive examples of these include urethane based, isocyanate-rich, moisture- curable, urethane prepolymers such as Morton Yokohama MS-90 available from Morton International of Ridgewood, IL, or Essex 435.20A. Additional examples of edge sealant with or without primer functionality include but are not limited to Essex 435.32, for applications in which the substrate to be bonded to glass is metal or plastic. Another type of edge sealant are those from thermosetting type of automotive clear coat compositions. The automotive clear coat compositions are those typically used in 'color-plus-clear applications for painting motor vehicles. In a color-plus-clear or base coat and clearcoat type of application, a composite coating is applied to a substrate. The clear coat is the transparent second film-forming composition usually applied as the top coat over the base coat and usually substantially unpigmented in that only minor or trace amounts of pigments may be present but the coating remains substantially transparent. The clear coat compositions include curable film-forming compositions having such film forming polymers as polyurethanes, polyanhydride- containing materials along with a polyhydroxy-containing material; acrylosilane polymers along with an acrylic polyol polymers, and optionally along with alkylated aldehyde condensate crosslinking agents such as melamine-formaldehyde; and polyisocyanate and a polymer having at least one group that is reactive with isocyanate such as a polyol and/or acrylic polyol. These compositions are formulated as either a one component or two component system. In the former formulation capping agents can be used as known in the art to delay reaction and in the latter case one component is at least one film forming polymer and the second component is the crosslinking material for the polymer. Of course the order of polymer and crosslinker can be the reverse of this. Also copolymers and polymer blends of these polymeric materials ca be used such as acrylic polyurethane copolymers and blended acrylic and polyurethane polymers. All of these compositions are well known to those skilled in the art of clear coat automotive compositions. These and other types of coating compositions useful in forming the edge sealant are described in U.S. Patent No. 5,891,981 (Mauer et. al . ) ; and the coating compositions and film forming polymeric materials of U.S. Patent Nos. 5,279,862; 5,286,782; and 5,545,824 all hereby incorporated by reference for their disclosures of such polymeric materials and compositions. Other suitable examples of commercially available clear coat compositions that may be the used for the edge 'sealant and the primer include PPG NCT clear coat and PPG CONCEPT® DCU 2020, DCU 2021, and DCU 2042 premium two- component coatings, and Stratoclear DCU 2082 all available from PPG Industries Inc. Pittsburgh, PA. Another example is the fast drying polyurethane type coating described in United States Patent Application entitled "Fast Drying Clear Coat Composition", Serial No. 09/086919, filed May 29, 1998, and also filed as a Patent Cooperation Treaty application as WO US99/09755 both disclosures of which are hereby incorporated by reference. The composition applied to the glass surface for forming the edge sealant can form a coating layer having a thickness such that the entire surface of the area of the glass to be bonded, or substantially so, is wetted by the composition for forming the edge sealing coating. A suitable thickness range for the edge sealant 34 can be from about 0.01 mils to about 3.5 mils (0.254 microns to 0.089 mm ) preferably 0.5 mil to 1.5 mil (1.27 to 3.81 microns). Any excess amount of edge sealant, whether or not used also as a primer, on the transparency to be bonded can be removed by allowing solvents in those materials to flash off. Sufficient flash off was found to occur at ambient temperatures in a period of only from about 5 seconds to about 15 minutes. Preferably the curable edge sealants cure at ambient conditions or slightly * elevated temperatures but at a temperature that is less than the glass transition temperature of the interlayer 34. One or more, preferably two, coating layers of any one or a combination of the edge sealants are applied to the transparency substrate and/or other substrates to be bonded thereto prior to bonding. A preferred combination is to utilize an amino silane adhesion promoter, such as Essex 435.18 silane coupling agent, adjacent the glass surface, followed by a layer of a single-component urethane primer, such as Essex 435.20A primer, deposited on the first layer of the edge sealant and primer. An adhesive for affixing the substrate to the support would be deposited on the primer 'layer or as noted above the primer can be one that is a one component primer and adhesive. The edge sealant can be formed on the transparency by application of an edge sealant composition by dipping, brushing, roll coating or like processes known to those skilled in the art. The composition can be applied to the transparency before or after any lamination step. Fig. 2 indicates the application after lamination. When the edge sealant composition is applied before lamination, it may be applied about the peripheral lateral and/or marginal edge of outer glass ply 22 as indicated in Fig. 4. In particular after coating 28 has been applied to glass ply 22, the edge sealant composition may be applied to the marginal area 38 and peripheral edge 40 of glass ply 22 to form edge sealant 34 to seal the edge of the coating 28 and protect it from the environment and chemical attack after lamination. When the edge sealant also serves as the primer or adhesive and primer for affixing the transparency as a glazing to an opening in a frame, the edge sealant would additionally be applied to cover the laminate transparency similar to that of Fig. 2 hereof. Other alternative arrangements of the edge sealant with the laminate as depicted in the Figures of U.S. Patent No. 5,122,403, as incorporated herein by reference, can be used with the edge sealant of this invention. Additionally retarding of the deterioration and/or corrosion of the coated transparency by the environment is accomplished by one or more of the following conditions. The functional coating 28 of Fig. 1 of the laminate has fine abrasions or scratches along the peripheral marginal area or border of the major surface of the sheet or ply for the transparency 20 such as 35 of Fig. 1. The abrasion marks are place in the border area before the heating of lamination of the transparencies having the functional coating 28. The fine abrasion is similar to that accomplished by hand rubbing the marginal or peripheral area of coating of the transparency 'with an abrasive article such as an abrasive sponge like a Scotch-Brite pad approximately 6 mm wide. Such useful abrasive articles include Scotch Brite pad ultra fine, Scotch Brite pad light 20bx, maroon Scotch Brite pad, and similar abrasive grit sandpapers and the like. Also the transparencies with the functional coating can be laminated at a higher temperature than the conventional temperature of lamination. Non-exclusive examples of such a higher temperature is up to about 50°F higher than conventional temperatures. Also it is preferred that the structure of the laminate is with the interlayer flush with the peripheral lateral edge of the laminate along with the ply or sheet that has the functional coating. The method and apparatus for forming laminated transparencies can be those described in U.S. Patent No. 5,698,053 (Carroll et . al . ) hereby incorporated by reference. EXAMPLE 1 Windshields Examples for Edge Sealant and Laminate Construction and Process A total of 126 laminates (12 inch by 12 inch) were fabricated under similar controlled conditions. The samples were submitted to two different corrosion tests and the edge stability number (ESN) measured. Each set of samples was * submitted to the two corrosion tests. One test (Test A) was the acid salt bath submersion at a pH 4.0 (H 2 SO 4 ) and 5% NaCl solution at 130°F for 300 hours. The second test (Test B) was the a salt fog test, which is a cyclic test at pH 4.0 and 1% NaCl for 60 cycles (days) . These are similar to American Society of Testing Materials (ASTM) tests B117 and G 85 annex 1, 2, 3, and 5. The edge stability number (ESN) is a ranking system to grade edge damage to laminates. It gives greater weight to those areas of deeper corrosion by a factor of the power of 2. An ESN number of zero would indicate no corrosion and an ESN number of 2,500 would indicate the entire perimeter of the windshield was corroded to a depth of 6 mm. The ESN is ' the metric to rank those processing parameters that impact corrosion of the laminates the most. Parameters investigated include interlayer location in relation to the glass in a laminate (scant -interlayer does not reach to the edge of the laminate and does not completely cover the glass surface) or (flush -the interlayer matches the surface area of the glass in the laminate) , interlayer adhesion (two different types of interlayers known as "RC" and "RB") , and coating scratches before heating. 300 Hour Acid Salt Bath test (Test A) The test results of the 300 hour acid salt bath are as follows. The laminate samples having two coating layers of edge sealant and having the interlayer flush at the edges of the laminate were the best performing with no corrosion. The laminate samples having excess PVB interlayer construction with two coats of edge sealant were the next best performers with an ESN of approximately 25. The laminate samples with a single coat of edge sealant and flush interlayer construction had an ESN of less than 50. The laminate samples with just a single coat of the edge sealant and excess PVB interlayer construction had an ESN of slightly greater than 50. The control windshield laminate was a commercial windshield coated with Sungate® coating which had an ESN of slightly greater * than 150. The laminate samples having two coat edge sealant with scant interlayer construction had about the same performance as the control of around 150 for ESN whereas the laminates with single coat of edge sealant had an ESN approaching 300. Test B Results from the 60 day salt fog test on the Essex primer edge sealant in conjunction with the acid/salt bath test of Test A, indicated the effectiveness of one and two coat application of the edge sealant in the prevention of corrosion on scant, flush, and excess interlayer ' constructions. Salt fog results concur with the acid/salt bath results and show that the edge sealant and primer system does work to reduce the corrosion rate and, hence, the amount of corrosion versus a laminate with an unsealed edge. The variations in the interlayer material can impact on the robustness of the laminated product. These tests also indicate that the two coat application of the edge sealant that also acts as the adhesive primer minimize corrosion. The results of the experiment show flush PVB interlayer construction, before heat scratches, and high firing temperature as being variables that produced the least amount of corrosion. The flush construction more than likely is better because of the difficulty in sealing the edge when the interlayer is scant. Scratching the functional coating has the "good" effect in preventing corrosion when done before heating the laminate. Because the test is a submersion test it is believed the scant PVB interlayer ranking is skewed because the corrosion was measured from the edge of the glass and not from the edge of the PVB interlayer where the corrosion actually starts to penetrate the laminate. The scant PVB interlayer construction acts as a strong variable because of the tendency for those areas of the laminate to collect moisture. EXAMPLE 2 Types of Edge Sealant A 3,200 hour QUV test was completed to determine if various edge sealant compositions would affect the PVB interlayer in a laminate. Laminates (3 inch by 12 inch) using polyvinylbutyral ("PVB") interlayer from a Solutia were prepared with the following edge sealant compositions: Material of U . S. Patent No. 5, 122, 403 PPG CONCEPT® 2020 clear coat PPG CONCEPT® 2021 clear coat Essex Betaprime 5004 mat .erial On each laminate one edge was left exposed to the UV light and the other edge was covered with lace to simulate a real windshield condition. A sample with no edge sealant was used as a control. Results were recorded after 500; 1,000; 1,500; 2,000; 2,500 and 3,200 hours. Any delamination defects were recorded as maximum depth of the defect, average depth of the defect, percentage of total length, and average area of the defect. The results after 3,200 hours for these edge sealant compositions were: These results showed no significant interaction between these edge sealants and the Solutia PVB. The edge sealant with the Essex urethane primer was tested as a single and double coating application approach. The one step glass primer from Essex coded 435.26 was tested versus double step 435.18 and 435.20A primers. However, two different batches of the 435.26 material failed to provide adequate adhesion under a variety of conditions. However acidic modified Essex 435.18 material as a one step application shows better retention of adhesion when priming is done at low humidity conditions versus high humidity conditions. Testing for one week water immersion at 50°C or in a 500 hour carbon arc Weatherometer was also done with the Morton-Yokohama primer MS-90 single step primer and Essex 5001 single step urethane primer. The Yokohama primer and Essex 5001 primer passed with excellent results. This indicates that a one step primer can be used as the sealant as well as a two step Essex primer. Primer application was done under low and high humidity conditions, with results showing less cohesive failure at low humidity which is undesirable. EXAMPLE 3 SIDELITES and Edge Sealant and Process Four edge sealant compositions were tested as edge sealant for the laminated sidelites having an electroconductive coating. These compositions were four types of PPG Coatings & Resins automotive 2K (two pack) clear coat compositions which included: PPG CONCEPT® 2020, PPG CONCEPT 2021, PPG 2082, and PPG 2042 products. Edge sealant application methods were also varied in order to determine if application prior to lamination has an effect on corrosion. Samples were made with each of the edge sealants on full size sidelites with electroconductive coatings. The sidelites were laminated using 1.8 mm SUNGATE® electroconductive coated SOLEX glass laminated with 30 mil (0.76 mm) PVB interlayer to 1.8 mm SOLEX glass. The glass is available from PPG and the two * types of PVB interlayer were used for this test are available from DuPont as B180SL and Solutia as RB-41. These samples were tested in two separate exposure tests: the 300 hour acid/salt bath (Test A above) and the 300 hour acid rain salt fog test (Test B above) . The corrosion was measured every 100 hours to determine the effectiveness of these materials to protect the electroconductive coating. Results of the acidic salt bath testing show a small amount of corrosion (ESN 0 to 14) for edge sealed, and unprotected areas. As in Example 1, a 60 day cyclic salt fog test for the four types of samples indicated that for sidelites the before heat scratches and higher temperature of processing the laminates were influential in retarding corrosion. Also the test indicated that Scant PVB interlayer construction was detrimental to corrosion resistance. The acid rain solution of pH 3.5 and cyclic fog, dry, humidity, and dry sequence produced ESN numbers similar to those of the acid salt bath test. The cyclic tests were conducted in a manner similar to those of GM 9540P/B and SAE J1563. EXAMPLE 4 Q-fog acid rain corrosion Test A total of five coated sidelite samples with edge sealant were placed on exposure in the Q-fog acid rain corrosion solution (pH 3.4) in a Q-fog environmental chamber to see if degradation occurs. These five samples involved application of different edge sealants to three sides of a laminated sidelite with an electroconductive thin film coating. The edge sealant compositions that were used consisted of 1) and 2) hot melt ethylene vinyl acetate ("EVA") 3M3792 and 3M3764, 3) and 4) PPG CONCEPT® DCU 2021 and DCU 2042, and 5) PPG Stratoclear DCU 2082. Also one sidelite having an electroconductive coating with no edge sealant was also placed on exposure as a control . The samples completed the 312 hours of exposure. * The following samples showed no degradation present at the protected edges: hot melt EVA 3M3792, PPG CONCEPT DCU 2021, and DCU 2042. However, the hot melt EVA 3M3792 did show signs of sealant material coming off the laminated edge of the sidelite. PPG Stratoclear DCU 2082 and EVA 3M3764 did reveal degradation in the edge sealed area, and the edge sealant was coming off the edge of the laminated sidelite. The laminated coated sidelite with no edge sealant revealed degradation in a couple of areas (1.5 mm). Q-fog 60 cycle acidic salt fog test The five coating samples with edge sealant also were ' placed on exposure in the Q-fog 60 cycle acidic salt fog test. The edge sealant composition was applied to three sides of a laminated sidelite with electroconductive coating. The edge sealants used were hot melt EVA 3M3792 and 3M3764, PPG CONCEPT® DCU 2021 and DCU 2042, and PPG STRATOCLEAR™ DCU 2082. Two sidelites with no edge sealants were also placed on exposure as experimental controls. The initial 60 cycle salt fog test showed positive results for preventing corrosion of the SUNGATE coated glass where the edge sealant was applied thoroughly to the edge. Although all of the samples on this initial round of tests showed some degree of corrosion, close examination of the samples revealed that even small areas of edge sealant voids would permit the corrosion to start. These small voids in the edge sealant application can occur at areas where there is a discontinuity in the windshield edge such as glass ply or PVB interlayer mismatch. Condition of the windshield edge, particularly the relationship of the PVB interlayer to the glass edge, is a factor, which can affect the efficiency of the edge sealant to prevent corrosion. It was noted that these types of edge conditions did not permit uniform coverage of the sealant using a one coat wiping action with a standard foam applicator. Outdoor Exposure Testing The first six month evaluation for PVB interlayer compatibility with SUNGATE® 100T coated glass in a laminated sidelite for field exposure samples was completed for two southern location exposure sites, Florida and Arizona. Two 30 mil (0.76 mm) PVB interlayer types, DuPont B180SL PVB and Solutia RB41 PVB, were tested for eight laminated sidelites. A total of four (two laminated with each PVB type) sidelites are on exposure at different locations. The configuration of the laminated sidelites are: 2.1 mm clear glass coated with SUNGATE® 100T coating/30 mil (0.76 mm) PVB/2.1 mm SOLARGREEN® glass. There was no PVB interlayer damage or corrosion observed for the first six months of exposure.

Claims: We claim : 1. An article comprising: at least one ply of material having a substantially transparent portion; at least one coating positioned over at least a portion of the ply of material; and at least one sealant over exposed portions of said coating to isolate the coating from the environment, wherein said sealant is selected from the group of automotive clear coat coating compositions, organosilanes, organotitanates, organozirconium compounds, and adhesive primers and any combinations thereof which protect said coating against degradation caused by exposure to the environment . 2. The article as in claim 1 wherein the sealant is polyurethane. 3. The article as in claim 1 wherein the clear coat is selected from curable film-forming compositions having such film forming polymers as polyurethanes, polyanhydride- containing materials along with a polyhydroxy-containing material; acrylosilane polymers along with acrylic polyol polymers, and optionally along with alkylated aldehyde condensate crosslinking agents; and polyisocyanate and a polymer having at least one group that is reactive with isocyanate selected from polyol and/or acrylic polyol. 4. The article as in claim 1 wherein the at least one ply is comprised of a first and second outer plies and wherein the coating is positioned between said plies with portions of said coating extending to a peripheral edge of said article. 5. The article as in claim 4 wherein said plies* are glass plies with said coating positioned there between. 6. The article as in claim 4 wherein said coating is selected from the group of solar performance coatings, electroconductive, and semiconductor coatings and combinations thereof. 7. The article as in claim 4 having at least one interlayer ply between said first and second plies and wherein said coating is disposed between at least one of the outer plies and the interlayer ply. 8. The article as in claim 4 further including directing member to supply an electric current through said coating to heat said coating and said article. 9. The article as in claim 8 wherein said directing member includes first and second bus bars positioned along opposite sides of and interconnected by said coating. 10. The article as in claim 8 wherein said sealant is a non-electroconductive material. 11. The article as in claim 8 wherein said coating and said bus bars are on a major surface of said first glass ply. 12. The article as in claim 8 having first and second interlayer plies positioned between said first and second glass plies and wherein said coating is disposed between the first and second glass plies. 13. The article as in claim 8 wherein said sealant extends from the lateral edge of the article to cover the peripheral marginal edge of the article to prime the article * as a glazing to cover an aperture. 14. The article as in Claim 8 wherein the sealant is present in at least two coats having a total film thickness of up to around 2 mils (0.051 mm) . 15. The article as in claim 8 wherein said sealant is selected from thermoplastic and thermosetting polyurethanes 16. The article as in claim 15 wherein the sealant is polyurethane coating composition from the curing reaction of polyisocyanate and polyol at a temperature from ambient to 'that less than the glass transition temperature of the interlayer. 17. The article as in claim 8 wherein the interlayer is flush with the peripheral edges of the ply with the coating. 18. The article as in claim 8 wherein said coating has a discontinuous portion around the peripheral edge of the coating in the laminate where the discontinuous portion constitutes abrasion marks. 19. The article as in claim 8 wherein the sealant is essentially free of polybutene copolymer, fluoropolymer and butyl based compositions in a predominant amount of the sealant . 20. The article as in claim 8 wherein the laminate is heated at an elevated temperature of up to 50°F greater than lamination temperature. 21. A method of fabricating a coated laminate including: the steps of applying a coating between a pair of opposing, outer plies each having two matching major surfaces", securing said plies to each other such that said coating is positioned therebetween, wherein portions of said coating extend to the peripheral edge of said laminate and are exposed to the environment, applying a weather resistant, sealant to said exposed peripheral lateral edge of said coating to retard degradation of said coating caused by exposure to the environment and extending to the peripheral marginal edge wherein said sealant is selected from the group of automotive clear coat coating compositions, organosilanes, organotitanates, organozirconium compounds, and adhesive primers and any combinations thereof. 22. The method as in claim 21 wherein said sealant applying step includes applying said sealant to said exposed coating edge and to a marginal edge portion of said coating adjacent said exposed coating edge, prior to said securing step. 23. The method as in claim 22 wherein said sealant is selected from a group of curable film-forming compositions having such film forming polymers as polyurethanes, polyanhydride-containing materials along with a polyhydroxy- containing material; acrylosilane polymers along with acrylic polyol polymers, and optionally along with alkylated aldehyde condensate crosslinking agents; and polyisocyanate and a polymer having at least one group that is reactive with isocyanate selected from polyol and/or acrylic polyol and essentially free of fluoropolymer based coating composition, a polybutene copolymer based coating composition, and a butyl based composition. 24. The method as in claim 23 wherein said plies are glass plies and said sealant applying step includes applying said sealant to a marginal portion of one of said » glass plies. 25. A coated vehicular transparency with a portion of the coating extending to a peripheral edge of the transparency comprising: a weather resistant primer/sealant completely around the peripheral marginal sides of at least one major surface of at least one ply and the peripheral lateral edge and side extending from that marginal side to seal the coating on the lateral sides to protect the coating against degradation caused by exposure to the environment and to prime the transparency for adhesion to a substrate wherein said primer/sealant is selected from a group of automotive clear coat coating compositions, organosilanes, organotitanates, organozirconium compounds, and adhesive primers and any combinations thereof.

Inventors: CLAAR JAMES A, FREEMAN GLENN E, YEH THOMAS, CLAAR, JAMES, A., FREEMAN, GLENN, E., YEH, THOMAS
Applicants: PPG IND OHIO INC, PPG INDUSTRIES OHIO, INC.
Application year: 1999
Main classification: C03C27
IPC codes: B32B3, B32B17, B60J1, C03C17, C03C27