Method of and agent for giving to a product some useful functions and product obtained thereby

The subject of the invention is a coating formed by depositing from an aqueous solution, free of solvents containing at least one silane, containing silanol groups on a glass substrate.

The invention belongs to the technical field of coatings on substrates and glassware. Products having coatings according to the invention have one or more utility functions.

More specifically, the invention belongs to the technical field of coatings that give improved substrates and products new features, e.g. better strength, color, impact strength and reduced transmission of infrared and ultraviolet radiation, by applying silane-containing solutions to the surface of the product to produce a silicon-containing product , oxygen and carbon coating on the surface.

Brittle materials in general, and especially glass materials, exhibit certain properties that have a smaller range than desired, such as tensile strength, impact strength and the ability to shield contents from harmful radiation. The manifestations of this state of affairs may arise as a result of factors such as imperfections or small amounts of impurities either in the body or on the surface of an article made of this material, or properties derived from the very nature of the material. Some ways to improve this situation include creating multilayer structures to obtain a product with a surface under compressive stress, and subjecting the surface to treatment in such a way that the polymer covers it both to protect the surface from blemishes and to provide, to a small extent, additionally strengthening the product .

Essentially, glass is one of the strongest materials man knows. Theoretically, standard silicate glasses should be able to withstand stresses of 14 to 20 gigapascals. In practice, however, typically the strength obtained is on the order of 70 megapascals (MPa). The explanation for the discrepancy between the predicted and measured values ​​is the existence of flaws or surface cracks. These defects significantly cause the cracking of siloxane crosslinking (Si-O-Si), which is the backbone of the glass structure. This damage to the glass acts to focus any applied force to the extent that it causes catastrophic destruction of the glass product typically at a much lower stress than would otherwise have been anticipated.

In the case of a glass container, surface defects or defects can arise from a number of sources, ranging from unalloyed kit components to scratches formed as a result of sliding on hard surfaces including other glass products. For example, in the case of a typical container manufacturing device, glass products can suffer severe damage when manipulated and from the moment they are manufactured. Contact with particles and moisture in the air, with other bottles, guides and other transmission equipment and conveyors on which they are transported, all this can lead to a significant reduction in the strength of the container as a result of flaws.

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Scientific research has long been aimed at finding solutions to alleviate problems related to the practical strength of glass. Numerous modifications to the forming and transporting process lead to increased strength, but even these manipulation achievements still do not preclude flaws from remaining on the surface. For this reason, considerable research efforts have been directed towards reducing the effects of blemishes once they have inevitably formed on the subject. These processes can generally be grouped into three main categories: surface treatment, heat treatment and surface coatings. The present invention is an example of the latter approach, the coating being applied to the surface of the product because its strength has already been compromised.

It is clear to those skilled in the art that due to the increase in strength of a fragile product, such as e.g. glass, less material will be needed to produce an article with substantially equivalent strength and overall mechanical performance. Hence, in the particular case of e.g. a glass bottle, this bottle may be lighter than its untreated counterpart, or may have the same weight with generally higher impact crack resistance or stress damage.

Some solutions to improve glass strength include U.S. Patent No. 4,859,636 to Aratani et al. In which metal ions on the glass surface are exchanged for ions with a larger radius to develop compressive stress on the surface. Poole et al. In U.S. Patent No. 3,743,491 also develops compressive stress on the surface, but introduces a polymeric coating to protect the surface from further abrasion.

Hashimoto et al. in U.S. Patent No. 4,891,241 describes subjecting a glass surface to treatment with a silane coupling agent followed by the application of a polymer coating containing acryloyl and / or methacryloyl groups, followed by irradiation or heat treatment to polymerize the molecules containing these groups .

Although each of the patents mentioned above provides an increase in the strength of this type of treated glass, they are not without their weaknesses. Some types of such treatment require more time than is obtainable during manufacture, forcing them to a separate process. There are also concerns about the safety and health of employees. The use and handling of solvents as well as acrylate and methacrylate compounds are of concern to the manufacturer, both from a health and safety point of view and in relation to the use or disposal of used materials.

In addition to the above, the problem of proper processing of the product to improve parameters other than strength (or in addition) raises the need to introduce stages that may border on a lack of economy. For example, the inclusion of a coloring agent as a coating in addition to the strength enhancer generally requires the installation of additional equipment, e.g. at a bottle production line, with associated capital and labor expenditure. The term color as used herein means the colorless or colored part of the visible spectrum, or the opaque part of the visible spectrum, whether black, white or any other

Other properties whose usefulness for fragile, and especially glass products have been recognized, include those obtained as a result of using e.g. materials for modifying the transmission of ultraviolet radiation, materials for improving the appearance of products with pitting or abrasive, lubricants and others, both separately and and in a combination of two or more additives designed to give the desired properties or functional functions.

The invention relates to coatings for one or more than one purpose, which give the products and substrates one or more utility functions, by applying the silane solutions described below to a glass substrate.

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The subject of the invention is a coating formed by depositing from a solvent-free aqueous solution, containing at least one silane, containing silanol groups on a glass substrate, with subsequent heating at a temperature of 50-250 ° C, with water evaporating and curing of the coating.

A characteristic feature of this coating is that it gives the substrate increased strength, while as a silane containing silanol groups it contains a product derived from a mixture of water and silane of formula [R (CH2)_m]_nSi (XR ') -._nwherein R 'is hydrogen, a substituted or unsubstituted hydrocarbon group of 1-10 C atoms, R is a saturated or unsaturated, straight, branched or cyclic hydrocarbon group of 1-10 C atoms, optionally substituted by hydrogen, halogen, silicon or substituted silicone, hydroxyl, carboxyl, carboxylate, epoxy, cyano, alkoxy, aminoalkyl, amide, carbamyl groups or combinations of these groups, n is 0-3, m is 0-6, X is halogen, oxygen, nitrogen or sulfur except that if X is halogen, its single valence is associated with a silicon atom and R 'is absent.

Preferably, the coated substrate is silicate glass.

Preferably, in the formula required above, R is a hydrocarbon group of 1-3 carbon atoms and m is 0.

Preferably also m is 0 and R is methyl, ethyl, propyl, vinyl, allyl, butadienyl, cyclopentyl and cyclohexyl.

Also preferred are compounds of the above formula in which n is 1, as well as compounds in which R has substituents such as epoxymethacryloxy, aryloxy, 4-hydroxybutyramide, 2-hydroxyamino and dialkylacetal groups.

Also preferred are compounds in which R 'contains silicon, especially those in which R' is a repeating unit of formula [R (CH_;)_m] PSi (XR)₃._p, ap is the number 1 or 2, and the other symbols have the meanings given above.

Preferably, the coating according to the invention comprises a silane applied by dipping a silane substrate or applied by spraying the substrate with a silane solution.

Furthermore, preferably the coating according to the invention comprises silane cured by keeping the coated substrate at an elevated temperature for a period of 1 minute to 1 hour, and especially by maintaining the coated substrate at ambient temperature.

Also preferably, the coating according to the invention comprises silane cured by applying energy to the coating on the substrate, and in particular by heating the coating on the substrate.

The coating according to the invention can be applied to glass products which may have a previously applied layer consisting of (or containing such materials) such as tin oxide, titanium oxide, silicon oxide or oxide of another metal or metal nitride, or mixtures of such materials, optionally with the addition of other components such as dopants to modify the electrical conductivity.

Substrates and products with a coating according to the invention have at least one improved property as a result of being applied to the product surface of this coating. The silane-containing coating contains a plurality of alkoxy groups attached to silicon and at least one silicon-bonded hydrocarbon moiety, and the solution can introduce at least one group whose action gives one or more functional functions selected, followed by curing of the coating on the product. The term function or functionality as used in this specification refers to the designation of a characteristic functional characteristic of a substrate or product that is used for decoration, or is useful or needed when it comes to using that substrate or product. Non-limiting examples of such utility functions are: color, increased strength, ability to block or modify (including reflection and refraction) radiation in various parts of the electromagnetic spectrum, scratch resistance and the ability to mask visible surface damage.

Regardless of the presence of another utility function, before or after application of the silane solutions described herein, silane solutions are useful in providing the substrate with selected utility functions, including (but not limited to)

169 347 description) with increased mechanical strength, dye, masking coating, modifier properties regarding ultraviolet (UV) radiation, surface grease, absorber or screen for infrared (IR) radiation, reflective or anti-glare coating in relation to any part of the electromagnetic spectrum from UV radiation to IR radiation or any combination of desired properties. The term masking coating as used herein means a coating the use of which improves the appearance of the material being manipulated or otherwise worn so that it adversely affects the appearance of the product. Giving modified properties relating to UV or IR radiation includes increasing or reducing the transparency of the coated article relative to UV or IR radiation, or changing the net refractive index of the coated substrate.

As examples of the features given to substrates and glass products by the coating according to the invention, mention may be made of the surface lubricity, strength of the glass bottle or ceramic plate and the decrease in UV transmittance into the transparent container. One or more improved properties may be combined in combination by introducing a molecular structure that produces such properties as silane molecules or molecules, or by mixing a solution containing other effective ingredients with a silane solution.

The term effective ingredient as used herein, whether in the singular or in the plural, means a compound or mixture whose composition, including, but not limited to, a particular molecular structure, generally gives the desired usable function of the surface undergoing such treatment. treatment. An example of an effective ingredient is an emulsion of a high molecular weight aliphatic hydrocarbon applied to the surface of a glass container, resulting in a surface that exhibits greater slippage than the surface that has not been treated. With respect to the coating of the invention, giving a variety of useful functions includes a combination of two or more properties in or on the substrate, such as increased strength and lubricity in the case of a glass container; lubricity, color and modification of UV radiation properties in the case of bottles, or increased strength and masking ability in the case of notch-sensitive glass material. For the purposes of this description, the term notch glass material is classified as brittle.

The coating according to the invention can be applied to a previously untreated surface of the product or applied to an outer layer whose composition is the same or different from that of the base material. By applying a water and silane composition to the product surface in which the silane contains hydrolysable groups attached to silicon and may also contain one or more organic moieties attached to silicon, one or more functional functions of the fragile product may be improved. Water is then removed, at least in part, resulting in a coating containing Si, O and C. The substrate may have any temperature above the freezing point of the solution, preferably from about 200 ° C, and most preferably from about 25 ° C to about 130 ° C.

The silane solution contains monomers or oligomers with SiOH groups. Those skilled in the art will understand that the term silanol group or SiOH group may be technically inaccurate. For the purposes of this specification, these terms refer to the hydrolysis product of a silicon containing moiety in which one or more hydroxyl groups are attached to silicon, even if these hydroxyl groups are only in equilibrium with unreacted compounds or products of subsequent reactions. The term hydrocarbon as used herein means a carbon compound containing hydrogen bonded to carbon and optionally containing substituents.

The silane solution contains materials selected to provide one or more desired functions, either as separate materials or as integrated groups used with the silane moiety. As noted above, silane moieties by themselves include monomers or oligomers containing SiOH groups. Material intended for broadcasting desired

169 A useful function can be added to the silane solution, e.g. as a lubricant. Alternatively or additionally, a dye may be included in the molecular structure of the silane itself.

Preferred materials of the invention are silanes containing at least one hydrolyzable group bonded to silicon, and preferably silanes containing a plurality of such groups with a group or material selected to give the desired utility function introduced into the solution or being an integral part of the silane molecule. Silanes containing at least two silicon-hydrolysable groups are preferred. In the most preferred embodiment, the silane uses one or more alkoxysilanes mixed with water to form an aqueous solution of compounds containing silanol groups and other functional groups. Most preferred alkoxysilanes are used in a concentration of from about 1 wt. up to about 100% by weight, preferably from about 5% by weight up to about 40 wt. and most preferably from 7 wt. up to about 25 wt.

The silane used in the present invention has the formula: [R (CH₂)_m]_nSi (XR ') 4_nwherein n is a number from 0 to 3, m is a number from 0 to 6, preferably m is a number from 0 to 3.

In the case where m is a numerical value of 0, preferably the hydrocarbon group with the symbol R is a straight chain group with a length of 1 to 3 and in the case of m is a number value from 2 to 6, it may be a group derived from a saturated or unsaturated hydrocarbon, such as methyl, ethyl, vinyl, propyl, allyl, butadienyl etc. These hydrocarbon chains may be substituted with groups that include (but are not limited to) units such as straight chain, branched chain and cyclic hydrocarbons, whether saturated or unsaturated; hydrogen, halogens, silicon and substituted silicon containing groups, hydroxyl, carboxyl, carboxylate, epoxy, cyano, alkoxy, aminoalkyl, amide, carbamoyl groups and combinations of these groups. Preferred groups are groups containing a hydroxyl, epoxy and acryloxy or methacryloxy function.

The group of formula XR 'is a group that is (or hydrolysable to the moiety) that can react with the surface of the treated article. The surface may contain metal = OH groups capable of condensing with the group of formula XR '. The preferred surface for this treatment is glass containing tin-oxygen or silicon-oxygen bonds.

The atom with the symbol X can be halogen, oxygen, nitrogen or sulfur, except that when X is halogen, its only valence is exhausted by its binding to the silicon atom and R 'cannot be present. X is preferably oxygen. The R 'group may be hydrogen or a group derived from a saturated or unsaturated hydrocarbon having from 1 to about 10 carbon atoms. It may contain oxygen, nitrogen and sulfur atoms in the chain, forming an ether, amine and thioether structure, etc. Further PL 'may include silicon and substituted silicon containing groups, such that the structure of the compound of formula [R (CH₂) m] nSi (XR ') 4-n is oligomeric, i.e. the R' group can be a repeating unit. The preferred carbon chain length is from 1 to 3. The most preferred group with the symbol R 'is methyl.

As noted, in the silane having the formula described above in the present description, R 'may be a repeating unit. The repeating unit is preferably a group of formula [R (CH₂)_m]_PSi (XR)₃- wherein R has substituents such as hydroxyl, epoxy, methacryloxy, acryloxy, 4-hydroxybutyramide, 2-hydroxyamino and dialkylacetal, p is a numeric value of 1 to 2, and the other symbols have the meanings given above.

Preferably, either one of the groups with the symbols R 'and R, or both, can contain or introduce one group or any combination of groups to give the substrate reinforcement, modify properties regarding UV radiation, shielding of IR radiation or other useful function. When the group with the symbol R 'introduces a utility function, it can undergo hydrolysis and in this way be removed from the parent molecule, but nevertheless remains a part of the resulting solution used to treat the substrate.

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In practicing the invention, a silane solution is prepared and allowed to stand for up to about 10 minutes. Although the inventors do not want to be limited by any theory, it is believed that this aging period, at least in part, allows the silane molecule to hydrolyze to form SiOH groups that may exist transiently or be in equilibrium with other types present in solution. Then, SiOH groups can interact with each other or other groups on the surface of the substrate to be treated.

The aged solution is applied to the surface of the substrate by spraying, brushing, dipping, immersion or by any method used to produce one or more effective coatings, including, for example, repeated dipping or spraying. Application can be carried out at any temperature used in the particular case. For example, in the case of glass products, the silane solution is preferably applied at the outlet or cold end of the tunnel compressor. Then, the resulting coating is cured by means of a single withdrawal or combination of withdrawal, at ambient temperature, or by means of an energy supply, such as ultraviolet or infrared radiation, for example. The preferred cure method is to heat the coated article at a temperature of about 50 ° C to 250 ° C.

After applying the basic molecule or its hydrolysis product to the surface of the material to be coated, the resulting outer surface serves as a material, providing one or more than one property consisting in strengthening the product, thanks to the complex structure of the substrate and coating. In case the group is associated with the group 'R' or when it is included in the group 'R', it may undergo hydrolysis and be removed from the parent silane molecule, but it will still be present in the coating applied to the substrate .

In order to provide spreadability to the product coated according to the invention, either one of the groups with the symbols R 'and R, or both, should contain 6 or more carbon atoms and include structures such as - (CH2)₈CH₃, - (CH2) and ₈CH₃, -CH₂CH₂(CF2) 5CF3 and the like, resulting in a slippery or lubricated outer surface of the substrate.

Similarly, R 'and R may include the structures shown in Table 1, in the case of materials providing modification of ultraviolet radiation properties. In these structures, R is an alkyl or aryl group containing from 1 to 10 carbon atoms.

Table 1

Structures that modify UV properties compound of formula 1 compound of formula 2 compound of formula 3 compound of formula 4

In the present invention, groups such as the p-nitrosonaphthal group and similar electron-rich structures confer chromophore properties. These groups include the groups shown in Table 2.

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Table 2

Chromophore groups group of formula 5 group of formula 6 group of formula 7 group of formula 8 group of formula 9

The term solution as used herein includes chemical solutions, suspensions, emulsions and mixtures, each of which may show complete or incomplete miscibility.

An aqueous silane solution is applied to the surface of the product by spraying, dripping, dipping, painting or any other technique suitable for applying liquids, vapors or aerosols. Once applied to the surface, the process, which appears to be a condensation reaction leading to the formation of siloxane bonds (Si-O-Si), is induced by e.g. microwave, IR or UV irradiation, or exposure to ambient or elevated temperature, at atmospheric pressure, or higher or lower than atmospheric.

Although not necessary to use the present invention, it can be theorized that in silicate materials, especially glass, there is a polysiloxane bond in the coating, both within the coating and between the coating and the surface. Silane coating, after binding to the surface can, among others act to eliminate surface cracks by creating Si-O-Si crosslinking across the flawed surface. The formation of siloxane bonds in the region with defects obviously works in a way that ensures an increase in destructive strength in a product such as e.g. a beer bottle etc. The observed increase in strength resulting from the use of the silane solutions according to the invention is over 350%.

By using the silane solutions according to the invention, including in the coating of the product of a part of the molecule having e.g. high UV opacity, it ensures that the contents of the bottle are protected against degradation.

The substrate may have any temperature above the freezing point of the solution, preferably from about 20 ° C to about 200 ° C, and most preferably from about 25 ° C to about 130 ° C.

Those skilled in the art are aware that other compounds may be incorporated into the silane solution to improve wetting, such as surfactants. Nonionic surfactants are particularly useful in this regard.

As noted herein, compounds capable of interacting with silanol groups can be incorporated into the silane solution to form a copolymer structure or to form interpenetrating structures and can be used together with silanes. As noted above, unsaturation or other molecular function can be introduced into the monomeric silane structure or into the solution in which the silane is present. Monomers that contribute to the formation of polymeric structures such as amino-formaldehyde, epoxy and polyacrylate are particularly useful in this case.

The examples given in the following section of the present specification do not specify the methods for sample preparation and testing, which methods are well known to those skilled in the art and as such do not form part of the present invention.

Strengthening.

Example 1. In this example, soda-lime glass rods are cut with a Vickers diamond to form about 50-micrometer scratches on the surface. These rod samples are tested for flexural strength and show an average strength of 56 MPa. Samples with identical scratches are coated by spraying with 10 wt. wod10

169 347 vinyltrimethoxysilane (VTMO) solution. The solution contains sufficient sulfuric acid to adjust the pH to 3.0 to 3.4. These samples are then heat treated for 15 minutes at 200 ° C and then tested for bending strength. As stated, the average strength value for these samples increases from 56 MPa to 90 MPa.

Example II Example 2 is a modification of Example 1 above. In this example, the samples are scratched rods and 10 wt. VTMO solution, acidified as in Example 1 above. This solution also contains 0.75 wt. nonionic surfactant. After curing, the scratched samples show an increase in strength from 56 MPa to 93 MPa.

Example III. Example III is identical to Example I above, except that methyltrimethoxysilane (MTMO) is used as the silane. Control samples show an average strength value of 62 MPa. After coating and hardening, the flexural strength increases to 96 MPa

Example IV Example IV is a repetition of Example II above, but using MTMO. The average strength value for the control samples is again 62 MPa, but the reinforced samples show an average value of 103 MPa.

Examples V and VI. Examples V and VI are a repetition of the above examples I and II, respectively, except that methacryloxypropyltrimethoxysilane (MPTMO) is used as the silane. In these examples, the average strength value for the control samples is 60 MPa.

The coated samples are subjected to thermal curing as described in the above part of the present description, but also subjected to additional UV irradiation to increase cure. The reinforced samples in example V achieve an average strength value of 126 MPa, and the samples in example 6 reach 124 MPa.

Camouflage.

Example VII. Bottles that have undergone tampering with normal cleaning and refilling cycles sufficient to have a generally rubbed and dull appearance are coated with a 10% aqueous silanol solution containing three silanes in a 1: 1: 1 ratio. Therefore, this solution contains glycidoxypropyltrimethoxysilane (GPTMO), 2- (3,4-epoxycyclohexyl) ethylthoxymethoxysilane (CETMO) and methyltrimethoxysilane (MTMO). The amount of each silane is about 3.33 wt. The solution contains sufficient sulfuric acid to adjust the pH to 3.0 to 3.4. To increase wettability, a non-ionic surfactant is added in an amount of 0.75 wt. The bottles thus coated have the appearance of bottles that have only undergone a minimal number of cleaning and refilling cycles.

Modifications of the transmission of ultraviolet radiation.

Example VIII. 2-Hydroxybenzophenone, whose molecules have the ability to shield ultraviolet radiation, is incorporated into GPTMO molecules. 1.85 g of this compound are added to 10 g of VTMO in solution and the resulting solution is allowed to stand for 24 hours at room temperature. The aged material is applied to the glass plate by dipping as shown in Example 1 above. After curing, the samples show a reduction in UV transmission.

Example IX. To the solution described in relation to Example 1 above, 2-hydroxybenzophenone in alcoholic solution is added. The resulting material is applied to a glass plate as shown in Example II above. Samples after curing show essentially the same reduction in UV transmission that was noted in Example VIII above.

Lubricity.

Example X. Example X is identical to Example VII above, except that the silane solution is CETMO, which still contains a polyethylene emulsion mixed with it, and the bottles have not undergone repeated filling and cleaning cycles. samples

169 347 controls show a slip angle of about 30 °. Treated bottles show a slip angle of about 10 °.

Color.

Example XI. A dye containing FD & C red No. 40 and FD & C red No. 3 is added to the solution intended to form the silane-containing coating of Example II above. The resulting material is used to coat transparent bottles by spraying. After curing, the bottles show a uniform red color. These bottles also show an improved breaking strength compared to control bottles.

Those skilled in the art will understand that the curing step of the method of the invention can be accomplished by using energy of any type and size sufficient to remove, e.g., water or other non-coating reaction product from the surface of the treated article, provided that the type of energy application is not harmful to the glass or the coating material. The curing step, being a combined action of energy and time, may involve the use of a small amount of energy over a relatively long time, or vice versa, the introduction of energy with restrictions as mentioned above, over a relatively short time.

Those skilled in the art who understand the principles and instructions set forth in this patent may think of modifications and improvements to preferred embodiments of the invention disclosed and described herein. Accordingly, the scope of the patent to be issued on this basis should not be limited to the embodiments of the present invention as set out herein, but rather should be limited only by the advances made in this field of technology by the present invention.

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169 347

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UP Department of Publications. Circulation of 90 copies

Price PLN 4.00