WO2021005616A1

WO2021005616A1 - A composition for lacquering temperable glass substrates

Info

Publication number: WO2021005616A1
Application number: PCT/IN2020/050555
Authority: WO
Inventors: Arkasish BANDYOPADHYAY
Original assignee: Saint-Gobain Glass France'
Priority date: 2019-07-08
Filing date: 2020-06-26
Publication date: 2021-01-14

Abstract

A composition for lacquering temperable glass substrates is provided. The composition of lacquering comprises of about 10 – 30% of silicone resin binder; about 10 – 30% of solid acrylic or urethane resin binder; about 2 – 50% of inorganic pigment; about 0.1 – 10% of adhesion promoter; and about 0.1 – 5% of surfactants dissolved in about 1 – 50% of organic solvent. Further the composition comprises about 2 – 20 % of solid particulate filler. The composition for lacquering glass substrates is devoid of glass frit and inorganic binders and withstands tempering temperatures as high as 700 ℃ when applied on the glass substrates. The present disclosure further relates to a method of making a lacquered glass article using the lacquer composition. The lacquered glass article prepared according to the present disclosure has the desired opacity and gloss value with increased mechanical resistance while remaining portable, storable, cuttable, washable and temperable/ toughenable.

Description

A COMPOSITION FOR LACQUERING TEMPERABLE GLASS SUBSTRATES

Technical Field

The present disclosure relates in general to a lacquer composition for glass substrates and more particularly to lacquer composition which can withstand the tempering temperatures of the glass substrates to provide temperable lacquered glass substrates. Further disclosed is a method of making a temperable lacquered glass thereof.

Background Glass lacquer compositions used, for example, for tinting glass substrates used in interior and exterior applications in buildings must be opaque, optically distortion-free, tenaciously adherent, reasonably hard and resistant to sunlight, sun heat, chemicals and moisture. Lacquered glasses are particularly intended for decorating building walls or furniture fronts. Organic paint coatings are widely used to obtain colored or lacquered glass which mainly comprise a mixture of a resin and organic or inorganic pigments. Also available are enamel compositions made from glass frit, inorganic pigments and a resin that burn away during heating. The main disadvantage of such organic paint coatings is the fact that the lacquered/ coated glass substrates can no longer undergo thermal quenching. By thermal quenching, the glass substrate is heated to a temperature above 600°C in air for a few minutes, before undergoing rapid cooling. These conditions are far too aggressive for these organic coatings, which degrade into elementary compounds such as carbon, carbon dioxide etc.

It is well established in the art that after thermal tempering process, the strength of the glass is significantly increased. Tempered glass has the added advantage of fragmenting into a multitude of small, blunt fragments in case of breakage. Therefore, a lacquered glass cannot have these properties unless the paint coating is applied to a previously tempered glass substrate. However, in this case the glass cannot be cut without breaking to a final desired dimension. As large volumes are unusual in the interior habitat where the dimensions are often customer-specific, organic paints are especially dedicated to non-tempered glass having the smallest mechanical properties. Other disadvantage of the organic paint coating is that the coating has very low mechanical resistance before it is fused with the underlying substrate by a heating step. Hence it is not possible to transport, cut, store or wash the lacquered glass until it is heated to high temperatures above 600°C for fusing. Thus the paint composition must always be deposited on the glass substrates cut to their final dimensions.

High temperature resistant coating on glass substrates based on inorganic binders such a silicates are known in the art. Such coatings due to their inorganic and adhesion properties with glass, sustain high tempering temperatures. On the other hand, silicone based paints for high temperature applications have also been known. Largely such heat resistant silicone coating systems are made for protecting and providing an aesthetic finish to various metal substrates such as carbon steel, cast iron, aluminized steel and aluminum used in applications ranging from boilers, chimneys, flue pipes, mufflers, silencers for combustion engines, engine cylinder heads, reactors and smokestacks. These metal surfaces provide for the inward diffusion of pigments present in the silicone based paints into the pores of the alloy substrates which are then sintered on the metal surface. On the contrary, glass substrates do not provide for diffusion and the silicone based binders degrade and burn off during the thermal tempering process leaving behind no binder for bonding the coating on to the glass substrate.

Thus silicone based paint composition described in the art cannot be used for an application pertaining to glass substrates. Reference is being made to the below patent applications disclosing on temperature resistant paint compositions for refractory coating comprising silicone based resins. Chinese application 105419628 relates to a high temperature resistant paint based on tetraethyl orthosilicate, titanium dioxide pigments, compound fillers and additives. Japanese application 11279488 relates to a heat-resistant coating composition suitable for metal structures, installations, piping and other devices exposed to severe environments comprising silicon resin, glass powder, pigment and solvent. Yet another Chinese application 105505203 discloses silicon resin heatproof paint.

The above mentioned paint compositions could have a good adhesion to glass substrates due to the presence of low glass frit powder in their formulations. However, such desired adhesion levels are possible only after a heating step involving temperatures above 550°C. Further the presence of glass frit in these compositions can lead to imprisonment of organic additives or impurities such as those contained in the fillers and/or pigments during the heating step. Burning partially, these organic additives or impurities will leave black residues, and therefore compel only the use of very dark colors, which is the case in the patents cited above.

Therefore, it is desirable to develop a glass lacquering composition having the desired opacity with increased mechanical resistance while rendering the lacquered glass substrates portable, storable, cuttable, washable and temperable. It is also further desirable to produce a lacquered glass product which can be used in its annealed form and in its tempered form by using a high temperature resistant lacquer composition that changes in color very minimally during the thermal tempering process. The present disclosure was developed by outlining the above objectives.

The present disclosure teaches a glass lacquering composition which can withstand the tempering temperature of glass substrates even after being transported, stored, cut, washed, edge grinded etc., following the coating of the lacquer composition on the glass substrate. The lacquer composition comprises about 10 - 30% of silicone resin binder; about 10 - 30% of solid acrylic or urethane resin binder; about 2 - 50% of inorganic pigment; about 0.1 - 10% of adhesion promoter; and about 0.1 - 5% of surfactants dissolved in about 1 - 50% of organic solvent. Further the lacquer composition comprises of about 2 - 20 % of solid particulate filler. The said lacquer composition is completely devoid of glass frit and inorganic binders thereby enabling the use of light colors without the downside of having organic residues and/ or impurities leaving black residues on the glass substrates post tempering process.

Summary of the Disclosure In one aspect of the present disclosure, a composition for lacquering temperable glass substrates is disclosed comprising about 10 - 30% of silicone resin binder; about 10 - 30% of solid acrylic or urethane resin binder; about 2 - 50% of inorganic pigment; about 0.1 - 10% of adhesion promoter; and about 0.1 - 5% of surfactants dissolved in about 1 - 50% of organic solvent. The lacquer composition is devoid of any glass frit and inorganic binders and withstands tempering temperatures as high as 700 °C when applied on the glass substrates.

In another aspect of the present disclosure, a method of making a temperable lacquered glass by using the lacquer composition of the present disclosure is disclosed. The method involves the steps of cleaning a glass substrate having a first surface and a second surface, coating the temperable lacquer composition on the first surface of the glass substrate and curing the second surface of the glass substrate coated with the temperable lacquer composition for about 10 - 20 minutes to obtain a temperable lacquered glass. The temperable lacquered glass obtained can be further handled and/or transported without mechanical damages to the lacquer composition and further be tempered at temperatures as high as 700 °C after being handled and/or transported.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings Embodiments are illustrated by way of example and are not limited in the accompanying figures. FIG. 1 illustrates a cross-sectional view of a lacquered glass article, in accordance with one embodiment of the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Embodiments disclosed herein are related to a composition for lacquering temperable glass substrates and a tempered lacquered glass article prepared according to the teachings of the present disclosure.

FIG. 1 illustrates a cross-sectional view of a temperable lacquered glass article 100 in accordance with one embodiment of the present disclosure. As shown, the temperable lacquered glass article 100 includes a glass substrate 110. The glass substrate 110 is provided with a temperable lacquer composition 200 on a first surface 101 of the glass substrate 110. In one embodiment of the present disclosure, the temperable lacquer composition 200 can be provided on a second surface 102 of the glass substrate. The temperable lacquer composition 200 is provided directly over the surface of the glass substrate 110 and comprises of a silicone resin binder, solid acrylic / urethane binder, pigments and surfactants mixed in organic solvents. In multiple embodiments of the present disclosure, the temperable lacquer composition 200 further comprises of a particulate filler. The temperable lacquer composition 200 of the present disclosure is devoid of any glass frit and inorganic binders.

The absence of glass frit or related materials such as glass powder, glass fibers, glass flakes etc., and inorganic binders is advantageous as this avoids trapping of organic additives or impurities coming from the surfactants or contained in the fillers and pigments present in the lacquer composition during the high temperature tempering process. If burned partially, these organic additives and impurities will leave behind black residues on the surface of the tempered lacquered glass substrates. These affect the aesthetic quotient of the products manufactured from the tempered lacquered glass substrates.

In one embodiment of the present disclosure, the temperable lacquer composition 200 is provided on the entire surface of the glass substrate 110 or in parts of the surface of the glass substrate 110. In a few other embodiments the temperable lacquer composition 200 covering about 10 - 80% of the surface area of the glass substrate 110 is provided. In such an embodiment, the temperable lacquer composition 200 may be provided in the form of a decorative pattern using screen printing techniques to obtain various shapes and sizes.

In one embodiment of the present disclosure, the temperable lacquer composition 200 of the present disclosure comprises of about 10 - 30% of silicone resin binder; about 10 - 30% of solid acrylic or urethane resin binder; about 2 - 20 % of solid particulate filler; about 2 - 50% of inorganic pigment; about 0.1 - 10% of adhesion promoter; and about 0.1 - 5% of surfactants dissolved in about 1 - 50% of organic solvent. In an alternate embodiment, the temperable lacquer composition 200 of the present disclosure is formulated without the presence of solid acrylic / urethane binder and a particulate filler, particularly when desired to provide an annealed lacquered glass substrate.

The temperable lacquer composition 200 of the present disclosure comprises of a silicone resin binder selected from the group consisting of methyl silicone, phenyl methyl silicone, epoxy silicone, polysiloxane, polysilazane or their combinations or their derivatives thereof. The silicone resin binders for the temperable lacquer composition were selected such that the selected silicone resin when used in the lacquer formulation can withstand high temperatures associated with the glass tempering or toughening process for a specified duration of time. The inventor of the present disclosure accidentally found that the chosen silicone resin was unable to withstand the tempering/ toughening temperature when used in a standalone formulation containing only the silicone resin. Whereas when the silicone resin binder was used along with the other ingredients described in the lacquer composition of the present disclosure, the silicone resin was able to withstand the tempering temperature. Further the silicone resin binder is polymerized owing to which the temperable lacquer composition 200 containing the silicone resin is found to be non-reactive and stable. In yet another preferred embodiment, the silicone resin content present in the temperable lacquer composition ranges between 10 - 30% of the total solid content of the temperable lacquer composition 200.

The solid acrylic or urethane resin binder present in the temperable lacquer composition 200 of the present disclosure help mitigate the heat transfer to the surface of the glass substrate 110 coated with the lacquer composition (102) during the process of tempering or toughening. Especially because these process steps of tempering or toughening are done by exposing the first surface 101 to high temperatures as high as 700 °C which conduct more heat than the second surface due to the presence of the coating 200 (silicone resin present in the lacquer composition lower the heat conductivity), these solid acrylic or urethane resin binder present in the lacquer composition 200 aid in increasing the heat conductivity of the second surface 102. This helps in balancing the heat conductivity of the first and second surfaces which in turn prevent the lacquered glass substrates from bending concavely during the tempering process due to the lower heat conductivity of the second surface 102 provided with the lacquer composition 200. Further the solid acrylic or urethane resin binder were also found responsible for the adhesive property, hardness and scratch resistivity of the annealed lacquered samples. The solid acrylic or urethane resin binder can be selected from acrylic beads, urethane beads or solid acrylic copolymers or their combination thereof.

The solid particulate filler present in the temperable lacquer composition 200 of the present disclosure reinforces the polymeric chain of the silicone resin binders and thereby contributes to the mechanical durability of the temperable lacquer composition 200 and as well renders the lacquer composition resistant to chemical and physical damages. In one embodiment of the present disclosure, the solid particulate filler is an inorganic particle selected from the group consisting of glass bubble, glass flake, ceramic beads, glass microbeads, mica particle, aluminum powder or boron nitride particles. In a preferred embodiment, mica particles are used as a filler in the temperable lacquer composition 200. In one aspect of the present embodiment, the filler constitutes about 2 - 20% of the temperable lacquer composition 200. In another aspect of the present embodiment, the inorganic particles present in the lacquer composition have a particle size ranging between 0.1 m - 50 m.

The temperable lacquer composition 200 further contains an inorganic pigment selected from the group consisting of titanium oxide, barium sulfate, zinc sulfate, zinc phosphate, zinc sulfide, zinc oxide alumina, chromium oxide, copper oxide, iron oxide, carbon black and phthalocyanine. In one aspect of the present embodiment, the pigments constitute about 2 - 50% of the temperable lacquer composition 200. In a preferred embodiment, the concentration of the pigment is maintained between 5 - 35%. The concentration of the pigment is adjusted in such a way that the viscosity of the temperable lacquer composition 200 does not increase during storage. This results in the temperable lacquer composition 200 exhibiting a good color conditioning and workability. Further the temperable lacquer composition 200 provides a finish with excellent depth of color.

The temperable lacquer composition 200 further contains adhesion promoters and surfactants. The adhesion promoter used in the composition of the present disclosure comprises of multiple epoxy and silane groups on each oligomer chain. Such an adhesion promoter promotes bonding of the temperable lacquer composition 200 to the glass substrates even at high tempering temperatures. The adhesion promoter is selected from compounds comprising multiple epoxy, alkoxy, amine or silane groups. In one embodiment of the present disclosure, the adhesion promoter is 3-glycidyloxypropyltrimethoxysilane or epoxy functional silane oligomer. The temperable lacquer composition 200 contains about 0.1 - 10% of adhesion promoters. The temperable lacquer composition 200 contains surfactants selected from the group consisting of defoamers, levelling agents, wetting agents and/or dispersion agents. In alternate embodiments of the present disclosure other surfactants such as rheology modifiers, flow agents, de-aerators or deformers can also be optionally used. Commercially available rheology modifiers, flow agents, levelling agents, de-aerators, wetting agents and dispersion agents may be used in the preparation of the temperable lacquer composition 200. However, the total amount of surfactants present in the temperable lacquer composition 200 is adjusted to be in the range of 0.1 - 5%.

Additionally, or optionally the lacquer composition 200 of the present disclosure may contain other components conventionally used in the preparation of lacquer solutions, for example, thickening agent, surface controlling agent, anti foaming agent, curing catalyst, extender pigment, and the like.

The various components of the temperable lacquer composition 200 described above are dissolved in 1 - 50% of organic solvent. The organic solvents are selected from the group consisting of xylene, naptha, butyl acetate, cellosolve acetate, propylene gycol monomethyl ether acetate or deacetone alcohol. In a preferred embodiment, the organic solvent used is butyl acetate.

The temperable lacquer composition 200 of the present disclosure may be coated on the glass substrate 110 using conventional coating techniques such as Meyer rod coating, curtain coating, roller coating, spin coating, bar coating or spray coating. The coating is cured at about 120° to 180°C for 10 to 20 minutes. The resulting coating is about 40 - 150 pm thick, preferably 45 - 125 pm thick, has good gloss and is opaque. The lacquer composition of the disclosure does not yellow on curing and gives a hard, durable, scratch-resistant, gasoline -resistant, weather-resistant, alkali- resistant coating which is suitable for all interior glass applications including but not limited to partitions, wall cladding and decorative purposes that necessitate having bright, opaque colors and improved aesthetics.

Further the lacquered glass substrate thus obtained according to the teachings of the present disclosure can be transported, cut, stored and/or washed and made to undergo other post-processing steps such as those not limited to edge grinding, bending etc., before subsequently being tempered or toughened at tempering temperature as high as 700°C for a specified duration of time. The temperable lacquer composition of the present disclosure withstands the said tempering and toughening temperature and shows a difference of color before and after tempering process (DE*) equal to or less than 2.0. Furthermore, the lacquered glass substrate thus obtained according to the teachings of the present disclosure can be used in its annealed form (without being subjected to the tempering/ toughening process) for all the earlier mentioned applications.

Examples

Example 1

Preparation of Temperable Lacquer Composition

Sample temperable lacquer composition according to the teachings of the present disclosure were prepared using the compounds listed in Table 1. The lacquer composition samples were prepared by mixing the components listed in Table 1 at their prescribed concentration in said amount of organic solvent. Commercially available adhesion promoter, levelling agent, wetting agent and dispersing agent were used for preparing composition 1 and 2. While composition 1 was prepared with the addition of solid acrylic / urethane binders, composition 2 was prepared without its addition. Likewise, filler particles were added to composition 2 and not composition 1. Compositions 3 and 4 were prepared similar to composition 2. The sample compositions were then allowed to stand for about 10 minutes to no air bubbles were present in the samples. The viscosity of the resultant composition was adjusted to ford cup 4 efflux time 15 - 150 seconds, more preferably between ford cup 4 efflux time 40 - 60 seconds.

Table 1 : Preparation of Temperable Lacquer Compositions

Example 2

Coating of Temperable Lacquer Composition

The surfaces of two glass substrates of size 300 x 300 mm (one with 3mm thickness and the other having 4mm thickness) were cleaned thoroughly to remove dust, dirt and other settlements on the glass surface. The lacquer compositions prepared according to example 1 were coated on the cleaned surface of the glass substrates using a Meyer Rod (rod size wire # 80, 90). The thickness of the lacquer coating was adjusted to be between 45 - 125 pm. The lacquer coated glass substrates were then cured in an oven at a temperature ranging between 120°C - 180°C for about 10 minutes with the second surface 102 of the coated glass surface facing the heat source. The lacquered glass substrates were found to be completely cured at the end of the curing step. The lacquer compositions were found to have formed an opaque, bright, uniform and continuous coating.

Example 3

Optical & Mechanical Properties Testing of Temperable Lacquered Glass Substrates

The mechanical properties such as hardness, adhesion strength and scratch resistance of the temperable lacquer compositions shown in example 1 coated on the surface of the glass substrates were tested. Opacity studies, cross cut test (ISO 2409 standard) and visible scratch test (EN 438 standard) were carried out. These experiments were conducted to test the mechanical and optical durability of the temperable lacquered glass substrates of the present disclosure in comparison with a conventional lacquered glass sample available in the market. Further the above mentioned values were measured after the lacquered samples were tempered at a temperature ranging between 650°C to 700°C for 4 - 5 minutes and the results are tabulated in Table 2.

Though the mechanical studies carried out showed similar results for samples prepared by the teaching of the present disclosure and the market sample, the sample prepared by the present disclosure showed a significantly high performance in visible scratch test before tempering of the lacquered glass samples. Such high scratch resistance before tempering of the lacquered glass sample is not true for the market sample tested. It was further noted that lacquered glass samples prepared using composition 2 of example 1 were observed to bend concavely during the glass tempering process for reasons outlined earlier in the description. Having said that composition 2 would yet be ideal for providing an annealed lacquered glass substrate that can be cut-to-size, edge grinded or put through other post processing steps after the coating of the lacquer composition described in the present disclosure before being installed. Samples prepared from composition 3 was found to have the desired properties before tempering but developed grey spots post tempering. However, the composition 3 is still recommended for annealed lacquered glass. Samples prepared from composition 4 exhibited slightly less mechanical durability compared to composition 1 and 2.

The visible scratch resistance tested using a sclerometer is an important criterion for lacquered glass substrates. This visible scratch resistance provides mechanical resistance against scratches that can appear during cutting and edge grinding of glass that result in chipping off of edges and also against rough handling of samples.

The high mechanical resistance (tested by Persoz hardness and cross cut tests) reported by the sample prepared using the present disclosure could be attributed to the lacquer composition comprising resins that are highly cross linked and polymerized.

Table 2: Optical and Mechanical Testing - Results

*BT-Before tempering process; *AT-After tempering process

Table 2: Optical and Mechanical Testing - Results contd.

*BT-Before tempering process; *AT-After tempering process

5

This better performance of these samples is attributed to the high degree of cross linking seen in the resins present in the lacquer composition. Example 4

Durability Testing of Lacquered Glass Substrates

The lacquered glass substrates prepared according to the teachings of the present disclosure were subjected to high humidity testing. To understand the effect of high humidity on the lacquer coating, the lacquered glass samples were placed in a humidity chamber at 50° C, 95% RH for 21 days, followed by comparison of optical characterization of the samples before and after high humidity testing. No appearance of blisters was observed post the test method.

Example 5

Gloss Measurements

The gloss value of the temperable lacquered glass substrates prepared according to the present disclosure was measured using a gloss meter with R 60° angle and the values are shown in table 3.

Table 3: Gloss Value of Lacquered Glass Substrates

*BT -Before tempering process; *AT-After tempering process

Samples prepared as per the teachings of the present disclosure was found to have similar gloss values of that of the market sample before tempering. Again the choice of resin for preparing the lacquer composition of the present disclosure contributes to the gloss value.

Thus the lacquered glass article 100 of the present disclosure is very unique with significantly high mechanical & optical properties, durability performance with additional operational freedom for lacquering the glass substrates at a manufacturing site, cutting/ edging etc., of the lacquered glass sample before transporting the lacquered samples to another processor site for tempering or toughening activities. Industrial Application

The lacquer composition 200 described in the present disclosure is devoid of glass frits and inorganic binders. As a result of which no imprisonment of any organic impurities or additives contained in fillers or pigments occurs. This completely avoids appearance of black residues post tempering or toughening of the lacquered glass substrates prepared using the lacquering composition 200. Further the lacquer composition of the present disclosure contains very low volatile organic compounds (VOC) and hence are very user friendly to be used in closed spaces like office and residential homes

Furthermore, the lacquer composition 200 of the present disclosure showed performance and durability properties which were on par with the market samples tested and in few tests such as visible scratch improved performance when compared to the conventional lacquer available in the market taken as a standard. Such increased scratch resistance for an annealed lacquered glass samples is most advantageous for the various applications outlined below.

The lacquered glass article 100 according to this disclosure may have various applications. The lacquered glass article 100 may, for example be used for various interior applications of buildings including but not limited to wardrobes, as doors for furniture, as partitions, in tables, shelves, in bathrooms, in shops displays, as wall covering or as spandrels. Such lacquered glass article 100 may also be used for decorative purposes as not limiting to a wall mount in office spaces, lift lobbies, receptions, kitchens, bathrooms and could also be possibly used as dinning and coffee table surfaces. More and more of these applications necessitate the glass article to be resistant to scratches, color fading/ bleaching, humidity exposure, moisture exposure and peeling of the lacquer layer.

Installation of the lacquered glass article 100 of the present disclosure in such applications achieve both aesthetic appeal and functional performance. The utilization of the lacquer composition of the present disclosure in the construction facilitates robustness against handling and storage degradation, and enhances flexibility for transportation in the as-coated state. Furthermore, the lacquered glass article 100 prepared by the present invention is compatible to be used both in its annealed form and tempered form. Therefore, the present disclosure carries the added advantage of safety.

The present disclosure also relates to a method of making the temperable lacquered glass article 100. The method comprises of steps 310 to 330. In multiple embodiments of the present disclosure, the lacquered glass article 100 illustrated in FIG. 1 may be obtained by performing the steps of the method.

In step 310, the glass substrate is first cleaned thoroughly by a mixture of ceria and calcium carbonate powders with the help of rotating brush. The air side of the glass substrate was cleaned. Following which, the cleaned glass substrate was dried thoroughly by compressed air flow knife. The surface was then silane treated. In step 320, desired viscosity and thixotropy of the lacquer composition was obtained by adding appropriate concentration of the various components of the lacquer composition. The lacquer composition was then applied on the surface of the glass substrate using a Meyer Rod technique.

Various patterns including dots, rectangular bars etc. of varying diameters and depths were created on the surface of the glass substrate. The thickness of the lacquer coating was controlled to be not more than 150 pm by using different rod size and moderating the coating parameters. The surface area to be covered by the lacquer composition of the present disclosure is varied based on the requirement. In one embodiment, the lacquer layer is coated to cover a surface area ranging between 10% and 80%. In the final step 330, the lacquered glass substrate was cured. The lacquered glass substrate was passed through a continuous convective IR oven with temperatures ranging between 110 °C and 180 °C. Residence time in the oven was between 10 minutes to 20 minutes. In alternate embodiments of the present disclosure, other drying techniques including thermal oven, heat combustion, UV curing can also be used.

Following lacquer coating and drying, the fillers present in the lacquer composition of the present disclosure thermally cured and binds with the glass substrate to provide green strength to the glass substrate. As a result, the enamel coated glass substrate can withstand subsequent transportation, washing (if needed). Further the lacquer coating does not yellow during the curing process and results in a hard, durable, scratch-resistant, gasoline-resistant, weather-resistant, alkali-resistant, acid-resistant, glossy coating. Following which the lacquered glass substrate can be tempered or toughened by heating the lacquered to temperatures as high as 700 °C to obtained a tempered lacquered glass.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of Elements

TITLE: A COMPOSITION FOR LACQUERING TEMPERABLE GLASS SUBSTRATES

100 Lacquered Glass Article

101 First Surface

102 Second Surface

110 Glass substrate

200 Lacquer Composition

300 Method

310 Step

320 Step

330 Step

Claims

We Claim:

1) A composition for lacquering temperable glass substrates comprising:

about 10 - 30% of silicone resin binder; about 10 - 30% of solid acrylic or urethane resin binder; about 2 - 50% of inorganic pigment; about 0.1 - 10% of adhesion promoter; and about 0.1 - 5% of surfactants dissolved in about 1 - 50% of organic solvent, wherein said composition is devoid of glass frit and inorganic binders and withstands tempering temperatures as high as 700 °C when applied on the glass substrates.

2) The composition as claimed in claim 1 further comprises and about 2 - 20 % of solid particulate filler.

3) The composition as claimed in claim 1 is opaque and applied directly on at least one face of the temperable glass substrates covering its surface area in entirety or in parts.

4) The composition as claimed in claim 1 , wherein the silicone resin binder is selected from the group consisting of methyl silicone, phenyl methyl silicone, epoxy silicone, polysiloxane, polysilazane or their derivatives or combinations thereof.

5) The composition as claimed in claim 1, wherein the solid acrylic or urethane binder is solid acrylic beads or urethane beads or solid acrylic co-polymers or their combinations thereof.

6) The composition as claimed in claim 1, wherein the solid particulate fillers are selected from the group consisting of glass bubble, glass flake, ceramic beads, glass microbeads, mica particles, aluminum powder or boron nitride particles.

1 7) The composition as claimed in claim 1 , wherein the inorganic pigments are selected from the group consisting of titanium oxide, barium sulfate, zinc sulfate, zinc phosphate, zinc sulfide, alumina, chromium oxide, copper oxide, iron oxide, carbon black or phthalocyanine.

8) The composition as claimed in claim 1, wherein the adhesion promoters comprise of multiple epoxy, alkoxy, amine or silane groups.

9) The composition as claimed in claim 1, wherein the surfactants are selected from the group consisting of defoamers, levelling agents, wetting agents and dispersion agents.

10) The composition as claimed in claim 1 has a difference of color between a temperable glass substrate coated with said composition before tempering and a temperable glass substrate coated with said composition after being handled and tempered defined as DE* equal to or less than 2.0.

11) The composition as claimed in claim 1 has a thickness ranging from 40 pm to 150 pm when applied on temperable glass substrates.

12) A method of making a temperable lacquered glass comprising the steps of:

cleaning a glass substrate having a first surface and a second surface; coating the lacquer composition as claimed in claim 1 on the first surface of the glass substrate in entirety or in parts;

curing the second surface of the glass substrate coated with the lacquer composition for about 10 - 20 minutes to obtain a temperable lacquered glass.

13) The method as claimed in claim 12, wherein step of coating the lacquer composition is done by Meyer rod coating, curtain coating, roller coating or spray coating.

2 14) The method as claimed in claim 12, wherein the temperable lacquered glass can be further handled and/or transported without mechanical damages to the lacquer composition.

15) The method as claimed in claim 12, wherein the temperable lacquered glass be further tempered or toughened at temperatures as high as 700 °C after being handled and/or transported.

16) A lacquered glass comprising the composition as claimed in claim 1.

17) A tempered lacquered glass comprising the composition as claimed in claim 1.

3