CATIONIC STABILIZATION

Abstract

The present invention relates to a composition comprising a wax, a cationic surfactant and an acid, wherein the molar ratio between the acid and the cationic surfactant is greater than 1.

Description

CATIONIC STABILIZATION Field of Invention The present invention relates to a composition comprising a wax, a cationic surfactant and an acid, wherein the molar ratio between the acid and the cationic surfactant is greater than 1. More specifically, the present invention relates to the use of a cationic wax dispersion to improve the protection of the external surface of glass containers and to a process for providing scratch protection to returnable glass containers. Background of the Invention Hollow glass containers are manufactured from molten glass in molds at high temperatures. Because the surface of these containers is fragile, and in order to preserve the strength of the glass and prevent any direct glass-to-glass contact between containers to avoid damage, their surface is coated immediately after the container is formed. In fact, in the glass container industry, for example, glass packaging containers, coatings are applied to improve and maintain their quality. Without coatings, glass items can be easily damaged even during the manufacturing process, and this LfrCfr Ln / Zznz / E / YIAI Ref. 339862 - 2 affects its appearance and weakens glass items. This type of coating includes tin, titanium, or other compounds based on metals or organometals that decompose under heat. This is the basis of the coating necessary to protect the surface of the glass vessel from damage such as abrasions and scratches, which result in a loss of strength. The need for high tensile strength in a glass vessel is particularly important when the vessels are mass-produced and therefore move rapidly to very close positions along high-speed conveyor belts. Today, in the manufacture of glass containers, a two-step coating process is implemented to achieve scratch resistance and a smooth, slippery feel. Therefore, glass containers typically receive two surface coatings: a hot coating applied just before annealing and a cold coating applied just after annealing. In the first step, a hot coating (HEC) is applied by chemical vapor deposition (CVD) of a metal-containing compound onto freshly formed, heated glass vessels placed in a single or double line. This first step is carried out - 3 normally at a temperature between 450 °C and 650 °C and is carried out as a thin layer of metal oxide. In a second step, a cold coating (CEC) is applied, typically by spraying a medium, in the form of an aqueous dispersion, once the glass containers have cooled to approximately 100°C. Partially oxidized polyethylene (PE) wax dispersions are generally used. This additional coating on the surface of the glass containers provides long-lasting protection, including scratch resistance and prevention of abrasion of the glass surfaces during filling and transport. Today, when applying CEC, it is common to use partially oxidized PE wax dispersions in an autoclave process. These dispersions are dissolved in water with the aid of a suitable surfactant. When carried out under optimal conditions, a fine wax dispersion is obtained. Depending on the type of surfactant, an ionic or non-ionic dispersion is achieved. Typically, a non-ionic surfactant, often ethoxylated alcohols, is used to minimize the effect of the pH and hardness of the water used to prepare the final dilution for application. The aqueous dispersion is supplied in concentrated form, LfrCfr Ln / Zznz / E / YIAI - 4 to avoid unnecessary water transport, and is diluted to the required concentration at the filling plant. The dispersion is highly diluted (typically 10 to 200 times with water) and must remain stable during dilution and application. This is even more important at elevated temperatures if dilution is done with warm water or if the dispersion is heated before application. Water quality varies around the world, and it's not the same everywhere. This involves variations in the concentration and pH of salts and ions in the water used for dilution. These salts and ions can affect the stability of the solution during the dilution process. Therefore, the use of demineralized water for further dilution is often recommended. However, this would require a water treatment system that isn't feasible globally. It's much more practical to use local water from the site where the facilities are located. Another problem is that if the diluted coating composition is not stable, it can cause the coating application equipment to clog, which would negatively affect the quality of the application and could lead to facility downtime. An objective of the present invention is to provide a coating composition for glass containers that can be easily diluted with any type of LfrCfr Ln / Zznz / E / YIAI - 5 water and avoid the installation of a water treatment system, and that it is stable during and after dilution. Another objective of the present invention is to provide a process in which any type of water used in industry, particularly tap water, can be used to dilute a coating composition for glass containers. Another objective of the present invention is to effectively reduce coating equipment downtime and blockages by using a stable coating composition that can be diluted with tap water. Brief Description of the Invention Surprisingly, a coating composition for applying a coating to the surface of glass containers has been discovered to comprise: a) a wax b) a cationic surfactant c) an acid where the molar ratio between the acid and the cationic surfactant is greater than 1, solve the problems mentioned above. Detailed Description of the Invention In one aspect, the present invention relates to a composition comprising: LfrCfr ίη / 77Π7 / E / YΙΛΙ a) a wax b) a cationic surfactant c) an acid where the molar ratio between the acid and the cationic surfactant is greater than 1. In a second aspect, the present invention relates to a process for preparing a coating composition comprising the step of mixing a wax with a cationic surfactant and an acid, the molar ratio between the acid and the cationic surfactant being greater than 1. In a third aspect, the present invention relates to a process for applying a coating to the surface of a glass container comprising a step i) of applying the composition of the invention to a glass surface, preferably the glass surface of a container. According to another aspect, the present invention relates to the use of the composition according to the invention, as a cold coating on a glass surface. The term wax is intended to refer to an organic compound comprising long alkyl chains, which has a melting point above 45 °C. The term dispersion is intended to refer to a colloidal system with a continuous liquid phase and a second discontinuous phase that is distributed throughout the continuous phase. - 7 After the application of the coating material, the continuous liquid phase evaporates and the discontinuous phase forms the coating. The term "water of any kind" is intended to refer to water that may contain a high concentration of salts. Preferably, this refers to tap water. The term surfactant is intended to refer to an active surface agent, which exhibits some surface or interfacial activity. By saying that an interval is from xay in the present invention, it is meant that the upper and lower limits of this interval are included, which is equivalent to at least xy up to y. The composition of the invention is preferably a coating composition, in particular a coating composition to be applied to a glass surface, in particular the glass surface of a container. Preferably, the composition of the invention is an aqueous dispersion. The wax in the composition is selected from natural and synthetic waxes or mixtures thereof. Waxes can be pure or they can be mixed with one or more oils. Natural waxes are selected from alkyl esters of fatty acids where the alcohol is primary - 8 and mixtures of these. Preferably, the natural wax is a Carnauba or Candelilla wax or a mixture of the same. Preferably, the synthetic wax is selected from the group consisting of partially oxidized polyethylene waxes having an acid value in the range of 1 mg KOH / g to 50 mg KOH / g, preferably from 10 mg KOH / g to 30 mg KOH / g, and even more preferably having an acid value of 20 mg KOH / g. When the composition of the invention is a concentrated aqueous dispersion, it may comprise from 5 to 25% w / w, preferably from 8 to 25% w / w, more preferably from 8 to 20% w / w, and even more preferably from 10 to 15% w / w of wax relative to the total weight of the composition. When the composition of the invention is a coating dilution, it comprises between 0.05% and 1% wax, preferably between 0.2% and 0.5% wax by weight relative to the total weight of the composition. The term cationic surfactant is intended to refer to the cationic surfactant itself or to its precursor, which can be transformed into the surfactant by generating a cation. Preferably, the cationic character of the surfactant is created by contacting the amine-type precursor with an acid. Preferably, the cationic surfactant (or its - 9 precursor) presents the formula (1): Ri — N—RI r3(1) where: • at least one of Ri, R2 or R3 represents an alkyl group, linear or branched, optionally ethoxylated, • at least one of Ri, R2 or R3 represents a hydrogen atom, • optionally, one of Ri, R2 or R3 represents an alkylamine group, ethoxylated or not. Preferably, the alkyl group comprises between 1 and 35 carbon atoms, preferably between 12 and 26 carbon atoms, more preferably between 14 and 22 carbon atoms, and even more preferably 16 carbon atoms. Preferably, when the alkyl group is ethoxylated, it contains a maximum of 5 ethoxylations, more preferably it has 2 ethoxylations. Preferably, the alkylamine group comprises between 1 and 35 carbon atoms, preferably between 12 and 26 carbon atoms, more preferably between 14 and 22 carbon atoms, and even more preferably 16 carbon atoms. Preferably, when the alkylamine group is ethoxylated, it contains a maximum of 5 ethoxylations, with greater LfrCfr Ln / Zznz / E / YIAI - 10 preference has 2 ethoxylations. Cationic surfactants are preferably selected from the group consisting of monoalkylamine, dialkylamine, ethoxylated alkylamine and alkyldiamines (such as Dinoram O® and Dinoram S® from CECA). When the composition of the invention is a concentrated aqueous dispersion, it may comprise from 1 to 15% w / w, preferably from 2 to 10% w / w, more preferably from 3 to 6% w / w of cationic surfactant relative to the total weight of the composition. When the composition of the invention is a coating dilution, it may comprise from 0.005 to 1.5% w / w, preferably from 0.01 to 1% w / w, more preferably from 0.015 to 0.6% w / w of cationic surfactant relative to the total weight of the composition. The acid in the coating composition is a Bronsted acid that has the general formula HA, i.e., an acid that can release a proton (H+). The acid can be a mineral acid or an organic acid. Preferably, the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, formic acid, acetic acid, propionic acid, butyric acid, malonic acid, itaconic acid, and fumaric acid. Preferably, the mineral acid is selected from the group consisting of hydrochloric acid and sulfuric acid. LfrCfr ίη / 77Ω7 / Β / YΙΛΙ - 11 Preferably, the organic acid comprises a maximum of 12 carbon atoms, preferably a maximum of 10 carbon atoms, more preferably a maximum of 6 carbon atoms, more preferably a maximum of 4 carbon atoms, and even more preferably a maximum of 3 carbon atoms. Preferably, the organic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, malonic acid, itaconic acid and fumaric acid, preferably acetic acid. The solubility of the acid in water is at least 10 g / 1, preferably at least 15 g / 1, more preferably at least 20 g / 1. When the composition of the invention is a concentrated aqueous dispersion, it may comprise from 1 to 15% w / w, preferably from 2 to 10% w / w, more preferably from 3 to 6% w / w of acid with respect to the total weight of the composition. When the composition of the invention is a coating dilution, it may comprise from 0.005 to 1.5% w / w, preferably from 0.01 to 1% w / w, more preferably from 0.015 to 0.6% w / w of acid relative to the total weight of the composition. The expression "the molar ratio between the acid and the cationic surfactant is greater than 1" is intended to mean that the molar amount of the acid exceeds the molar amount of the surfactant. LfrCfr ίη / 77Ω7 / Β / YΙΛΙ - 12 of the cationic surfactant. Preferably, the molar ratio between the acid and the cationic surfactant is at least 1.01, preferably at least 1-1, more preferably at least 1.2, more preferably at least 2, and even more preferably at least 3. Preferably, the molar ratio between the acid and the cationic surfactant is at most 5. Preferably, the composition comprises one or more additional additives, preferably selected from the group consisting of biocides, bactericides, preservatives, an ester alcohol, glycol ether, colorants, emulsion destabilizers, perfumes, flavorings, UV absorbers, light absorbers, shock absorbers, surfactants other than sorbitan esters, oils other than mineral oils and the like. The composition of the invention may be a coating dilution that is applied directly as a coating, or a concentrated aqueous dispersion that is subsequently diluted to obtain a coating dilution. The coating dilution can be applied to a glass article, for example, a glass container. The expression concentrated aqueous dispersion is intended to refer to the fact that the aqueous dispersion will be subsequently diluted to obtain a coating dilution. - 13 Later in this document, the expression concentrated aqueous dispersion is also referred to as aqueous dispersion. Preferably, the coating dilution comprises 0.5 to 10% w / w of the concentrated aqueous dispersion relative to the total weight of the coating dilution. Otherwise, the concentrated aqueous dispersion is diluted 10 to 200 times to obtain the coating dilution. Preferably, the composition of the invention is diluted in a solvent to obtain the coating dilution. Preferably, the solvent is water, more preferably tap water. Preferably, the composition of the invention comprises between 90 and 99.5% by weight of solvent relative to the total weight of the composition. The present invention also relates to the use of the composition according to the invention for the preparation of a coating dilution, in particular with tap water. The present invention also relates to the use of the composition according to the invention as a coating dilution. Another object of the present invention is a coating dilution comprising the composition according to the invention. Another object of the present invention is the use of the LfrCfr ίη / 77Ω7 / Β / YΙΛΙ - 14 composition according to the invention, as a cold coating on a glass surface. Another object of the present invention is a process for preparing a composition of the invention, comprising a step of mixing a wax with a cationic surfactant and an acid, the molar ratio between the acid and the cationic surfactant being greater than 1. The wax, cationic surfactant, acid, and molar ratio are as previously defined. The wax, cationic surfactant, and acid can be mixed together or in several steps. Preferably, the wax and cationic surfactant are mixed in the first step, and then the acid is added. Alternatively, at least some of the acid is added while mixing the wax and cationic surfactant. Preferably, the composition of the invention is an aqueous dispersion. The acid can be added in one step or several steps. In one embodiment, the acid is added in one step. In another embodiment, a portion of the acid is added when preparing the concentrated coating dispersion, and a second portion of the acid is added later, preferably during the dilution step, to achieve a molar excess of the acid. Excess acid relative to surfactant can - 15 add to the solvent, preferably water, used for dilution. The present invention also relates to a process for applying a coating to the surface of a glass container comprising a step i) of applying the composition of the invention to a glass surface, preferably the glass surface of a container. Step i) can be carried out by bringing the composition of the invention into contact with the glass surface. This contact is preferably achieved by a coating application method, preferably selected from the group consisting of spraying, immersion, and the use of a coating applicator. Preferably, step i) is implemented on a glass surface at a temperature in the range of 10 °C to 150 °C. Preferably, when step i) is applied in a filling chain on a glass surface, the temperature is in the range of 15 °C to 70 °C, more preferably between 20 °C and 40 °C. Conveniently, the means for applying the coating formulation or dilution to a glass surface by spraying comprise spraying means. According to one embodiment, the means for applying the coating formulation or dilution to a glass surface by immersion comprise a receiver containing LfrCfr Ln / Zznz / E / YIAI - 16 the formulation or dilution of coating in which the containers are immersed. The coating applicator can be a brush, capillary, sponge, fiber, or similar. The coating material is applied to the surface of the glass article through the contact area between the coating applicator and the surface of the glass article. Preferably, the coating process is for coating a glass container, and the coating process further comprises a prior step i') of applying a metal oxide treatment to the glass surface. Conveniently, the metal is selected from tin and titanium. Another object of the present invention is a glass surface that can be obtained by the coating process according to the invention. Preferably, the glass surface is a glass container, more preferably, a glass bottle. Examples Example 1 Arkema Kercoat® 500 containing 0.013 mol of acetic acid and 0.015 mol of cationic surfactant was used to prepare dilutions with a concentration of 1% (Compositions A and D), 2% (Compositions B and E) and 3% (Compositions C and F) by weight of Kercoat® 500 relative to the weight LfrCfr ίη / 77Π7 / E / YΙΛΙ - 17 total dilution. In Table 1, the water used for dilution was tap water from Arkema's facilities in Vlissingen, the Netherlands. In Table 2, the water used was demineralized water. The dilutions were stored at 65 °C for one week, and their stability was assessed. To assess the stability of the composition, the turbidity of the compositions was measured using the ISO 7027 standard. The results are provided in FNU (formazin nephelometric units). The results are shown in Tables 1 and 2 below: LfrCfr Ln / Zznz / E / YIAI Table 1 Table 1 Arkema Vlissingen Tap Water Dilution Stability Measurement in FNU Days Composition A Composition B Composition C 0 21 38 51 0.25 888 127 54 1 1300 1300 64 2 1300 1300 95 3 1300 1300 162 6 1300 1300 938 7 1300 1300 1300 LfrCfr ίη / 77Π7 / E / YΙΛΙ Table 2 Table 2 Demineralized Water Dilution Stability Measurement in FNU Days Composition D Composition E Composition F 0 18 33 45 0.25 18 33 43 1 18 32 44 2 17 31 42 3 18 31 41 6 19 33 42 7 18 32 42 The results show that cationic wax dispersions are not stable when diluted in tap water, contrary to what is observed when using demineralized water. Example 2 Example 1 was reproduced using tap water (Compositions A to C), and the compositions were supplemented with 0.017 mol (i.e., to a total content of 0.030 mol in the composition), 0.033 mol (i.e., to a total content of 0.046 mol in the composition), and 0.050 mol (i.e., to a total content of 0.063 mol in the composition) of acetic acid, respectively. The results are shown in Table 3 below. LfrCfr Ln / Zznz / E / YIAI Table 3 Measurement of dilution stability in FNU Days Composition A + 0.017 mol of acetic acid Composition B + 0.033 mol of acetic acid Composition C + 0.050 mol of acetic acid 0 19 37 50 1 21 34 45 2 27 34 45 3 27 34 45 6 103 34 45 7 461 34 45 A comparison of examples 1 and 3 shows a significant increase in the stability of the composition when the acid is present in a ratio of more than one to the cationic surfactant. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A composition, characterized in that it comprises: a) a wax b) a cationic surfactant c) an acid wherein the molar ratio between the acid and the cationic surfactant is greater than 1.

2. The composition according to claim 1, characterized in that the molar ratio between the acid and the cationic surfactant is at least 1.01, preferably at least 1.1, more preferably at least 1.2, more preferably at least 2 and even more preferably at least 3.

3. The composition according to claim 1 or 2, characterized in that the cationic surfactant is selected from monoalkylamine, dialkylamine, ethoxylated alkylamine and alkyldiamines.

4. The composition according to claim 1 or 2, characterized in that the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, formic acid, acetic acid, propionic acid, butyric acid, malonic acid, itaconic acid, and fumaric acid.

5. The composition according to claim LfrCfr Ln / Zznz / E / YIAI - 21 1 or 2, characterized in that the wax is selected from alkyl esters of fatty acids wherein the alcohol is a primary one and a mixture thereof, preferably a Carnauba or Candelilla wax or a mixture thereof.

6. The composition according to any of claims 1 to 5, characterized in that it is in the form of an aqueous dispersion.

7. The composition according to any of claims 1 to 5, characterized in that it comprises 5 to 25% w, preferably 8 to 25% w, more preferably 8 to 20% w and even more preferably 10 to 15% w of wax by weight of the composition.

8. A composition according to any of claims 1 to 7, characterized in that it comprises between 90 and 99.5% w / w of solvent with respect to the total weight of the composition.

9. A process for preparing a coating composition, characterized in that it comprises a step of mixing a wax with a cationic surfactant and an acid, the molar ratio between the acid and the cationic surfactant being greater than 1.

10. A process for applying a coating to a glass surface, characterized in that it comprises a step i) of applying the composition in accordance with LfrCfr Ln / Zznz / E / YIAI - 22 any of claims 1 to 8, onto a glass surface, preferably the glass surface of a container.

11. The composition according to any of claims 1 to 8, for use as a cold coating on a glass surface.

12. Glass surface, preferably a glass container and even more preferably a glass bottle, characterized in that it can be obtained by the process according to claim 10.