阅读说明：本技术 用于处理玻璃容器的方法 (Method for treating glass containers ) 是由 L.C.赫克曼 于 2018-12-21 设计创作，主要内容包括：本发明涉及用于处理玻璃容器或玻璃餐具的方法。特别地,其涉及用于处理玻璃容器的方法,包括清洁或洗涤步骤和向玻璃容器表面施加涂层的步骤。更特别地,本发明涉及用于处理可回收玻璃容器的方法,包括清洁或洗涤步骤和向玻璃容器表面施加涂层的步骤。(The present invention relates to a method for treating glass containers or glass cutlery. In particular, it relates to a method for treating glass containers comprising a cleaning or washing step and a step of applying a coating to the surface of the glass container. More particularly, the present invention relates to a method for treating returnable glass containers comprising a cleaning or washing step and a step of applying a coating to the surface of the glass container.)

1. A method for processing glass containers, the method comprising the steps of:

i) cleaning by washing the container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃,

ii) applying a coating on the container with a composition comprising a wax compound (W1).

2. The method of claim 1, wherein the glass container is a returnable glass container.

3. A method according to any of claims 1 to 2, characterised in that the cleaning composition comprises one or more alkalinity sources.

4. The method according to any of claims 1 to 2, characterized in that the cleaning composition comprises hydroxide ions.

5. The method according to any one of claims 1 to 4, characterized in that the wax compound (W1) has a melting point below 85 ℃, preferably below 83 ℃.

6. The method according to any one of claims 1 to 4, characterized in that the wax compound (W1) has a melting point between 60 ℃ and 85 ℃ and preferably between 65 ℃ and 80 ℃.

7. The process according to any one of claims 1 to 6, characterized in that the saponification number of the wax compound (W1) is higher than 20mg KOH/g.

8. The process according to any one of claims 1 to 6, characterized in that the saponification number of the wax compound (W1) is between 20 and 250 mg KOH/g.

9. The method according to any one of claims 1 to 8, characterized in that the acid value of the wax compound (W1) is higher than 1 mg KOH/g.

10. The method according to any one of claims 1 to 9, characterized in that the wax compound (W1) has an acid number of less than 24 mg KOH/g.

11. Method according to any one of claims 1 to 8, characterized in that the acid number of the wax compound (W1) is between 2 and 24 mg KOH/g, still more preferably between 2.5 and 23 mg KOH/g, even still more preferably between 3 and 22 mg KOH/g, advantageously between 3.5 and 21 mg KOH/g, and more advantageously between 4 and 20mg KOH/g.

12. A process according to any of claims 1 to 11, characterized in that the cleaning composition comprises a zinc compound, preferably in ionic form.

13. A method according to claim 12, characterized in that the detergent composition comprises an amount of zinc ions of between 0.00025 and 0.1 mol/l.

14. Method according to any one of claims 4 to 13, characterized in that the amount of hydroxide ions in the washing composition is between 0.05 and 2.5 mol/l.

15. A method according to any of claims 4 to 14, characterised in that zinc or aluminium ions in the detergent composition and OH in the detergent composition^-The molar ratio between the ions is at least 0.002.

16. A method according to any of claims 4 to 15, characterised in that zinc or aluminium ions in the detergent composition and OH in the detergent composition^-The molar ratio between the ions is at most 0.5.

17. The method according to any one of the preceding claims, wherein the cleaning step i) is performed before the coating step ii).

18. Use of a method according to any one of claims 1 to 17 for reducing the burst pressure loss.

[ field of the invention ]

The present invention relates to a method for treating glass containers or glass cutlery.

In particular, it relates to a method for treating glass containers comprising a cleaning or washing step and a step of applying a coating to the surface of the glass container.

More particularly, the present invention relates to a method for treating recyclable (returnable) glass containers, the method comprising a cleaning or washing step and a step of applying a coating to the surface of the glass container.

[ problem ] to

Hollow glass containers are made from molten glass in a mold at elevated temperatures. Since the surfaces of these containers are fragile and in order to maintain the strength of the glass and to prevent any direct glass-to-glass contact of the individual containers to avoid damage, they are surface coated immediately after the containers are formed.

Such coatings comprise tin or titanium or other thermally decomposable metal or organometallic based compounds. This is the basis for the coatings needed to protect the glass container surfaces from damage (e.g., abrasion and scratching) that results in a loss of strength of the glass container. The need for high tensile strength in glass containers is particularly acute when the containers are produced in large quantities and moved rapidly in close proximity along a high speed conveyor line.

Nowadays, in the manufacture of glass containers, in order to obtain scratch resistance and smoothness of the glass containers, two-step coating is used. Thus, glass containers typically receive two surface coatings, one on the hot end, just prior to annealing, one on the cold end, just after annealing.

In a first step, a so-called hot-end coating (HEC) is applied on the as-formed, hot and single-or twin-line positioned glass container by means of Chemical Vapour Deposition (CVD) of a metal-containing compound, as described previously.

In the second step, a so-called cold-end coating (CEC) is applied, usually in the form of an aqueous dispersion by means of a spraying device. A partially oxidized polyethylene wax dispersion is usually applied. With such additional coatings on the glass container surface, durable protection is provided, including scratch resistance and prevention of scratching of the glass surface during filling and shipping.

The glass containers can be recycled and reused. Such returnable glass containers are collected, cleaned and refilled, if reused.

The cleaning step for returnable glass containers usually involves caustic washing. During the alkaline cleaning process, the cold side coating and the hot side coating are gradually corroded. After several cycles, the unprotected bare glass surface will be exposed and begin to scratch. Thus, the protective coating may be applied after washing and before refilling, but in the event that the glass surface is corroded and the hot end coating is reduced or even removed, the adhesion of the protective coating on the glass container surface is much lower than the initial cold end coating.

Loss of the initial cold end coating and the cold end coating (particularly by caustic washing) results in a loss of initial strength of the glass container, scratching occurs, and the fracture pressure of the recycled glass container is reduced. This reduction in burst pressure and increase in scratching during the first 5 to 10 recycling rounds has been significant, greatly increasing the risk of container rupture and limiting the useful life of the glass container.

Sometimes, surface scratches are simply masked on recycled glass containers after washing.

There remains a great need for more efficient glass processing and glass processing methods and glass coatings for recyclable glass containers.

It is an object of the present invention to increase the useful life of recyclable glass containers.

It is another object of the present invention to provide a method of increasing the useful life of recyclable glass containers.

It is another object of the present invention to reduce the rate of loss of burst pressure of recyclable glass containers during recycling. The burst pressure of a glass container that is recycled or reused 10 times should desirably be 50% of the initial burst pressure of a virgin container (nearcontainer) from a glass manufacturing plant. Preferably, the burst pressure of a glass container that is recycled 25 times should desirably be 50% of the initial burst pressure of a virgin container from a glass manufacturing plant.

It is yet another object of the present invention to provide a method that allows for the protection or reduction of damage to the hot starter coating while reducing the loss of burst pressure of the glass container during recycling.

It is a further object of the present invention to provide a method which enables the thickness of the container, or in other words the weight of the container, to be reduced while still having a sufficient rupture pressure of the recirculating container.

It is a further object of the present invention to greatly improve the transport of the recirculation vessel during filling.

An additional object of the present invention is to provide a method that avoids scratching the surface of glass containers, particularly recycled recyclable glass containers.

It is yet an additional object of the present invention to provide a method that maintains the original surface appearance of the container and does not require a masking coating.

Surprisingly, it has been found that by combining a washing process with a specific coating application, some or several of the aforementioned problems can be solved.

Background of the invention Prior Art

Document US 4,001,133 describes a method of washing glassware and an inhibitory cleaning solution. Glassware was washed with an inhibitory caustic aqueous cleaning solution containing a soluble zinc compound, a synthetic organophosphate anionic surfactant, a low foaming synthetic alkoxylated nonionic surfactant and a chelating agent. The protective coating is polyethylene applied over the metal oxide layer. The cleaning solution prevents unsightly discoloration and maintains strength.

Document US 4,908,148 describes a rinse additive composition that provides glassware protection, which contains an insoluble zinc compound to inhibit glassware corrosion that may occur in an automatic dishwasher.

Document US2006/0128602 describes a warewashing composition for an automatic dishwasher, and methods of making and using the same. The warewashing detergent composition includes a cleaning agent, an alkalinity source, and a corrosion inhibitor. The corrosion inhibitor includes sources of aluminum ions and zinc ions.

None of the cited prior art discloses a method involving the application and reapplication of a coating to a cleaned glass container, nor a method involving the combination of a cleaning step and the application of a coating.

[ summary of the invention ]

Surprisingly, a method for treating glass containers has been found, comprising the steps of:

i) cleaning by washing the glass container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃, and

ii) applying a coating on the surface of the glass container with a composition comprising a wax compound (W1)

Producing a recycled glass container that retains its initial hot end coating and has reduced burst pressure loss.

Surprisingly, it has also been found a method for treating glass containers, comprising the steps of:

i) cleaning by washing the glass container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃, and

ii) applying a coating on the surface of the glass container with a composition comprising a wax compound (W1)

Increasing the useful life of the recyclable glass container and allowing for more cycles.

Surprisingly, it has additionally been found a method for treating glass containers, comprising the steps of:

i) cleaning by washing the glass container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃, and

ii) applying a coating on the surface of the glass container with a composition comprising a wax compound (W1)

Allowing the thickness of the returnable glass containers to be reduced while maintaining at least the same burst pressure as thicker returnable glass containers or heavier containers not processed by this method.

Surprisingly, it has also been found that the use of a cleaning composition comprising a zinc or aluminum containing compound for cleaning recyclable glass containers at temperatures less than 90 ℃ and the use of a coating composition comprising a wax compound (W1) for coating application on the surface of the glass containers produces recycled glass containers that retain their initial hot end coating and have reduced burst pressure loss and adequate lubricity.

[ detailed description of the invention ]

In a first aspect, the present invention relates to a method for handling glass containers, the method comprising the steps of:

i) cleaning by washing the glass container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃, and

ii) applying a coating on the surface of the glass container with a composition comprising a wax compound (W1).

In a second aspect, the present invention relates to the use of a washing composition comprising a zinc or aluminium containing compound for washing recyclable glass containers at a temperature of less than 90 ℃ and the use of a coating composition comprising a wax compound (W1) for coating application on the surface of glass containers.

In a third aspect, the invention relates to a glass container cleaned at a temperature of less than 90 ℃ by a washing composition comprising a zinc or aluminium compound and having a coating comprising a composition comprising a wax compound (W1) on the surface of the glass container.

The term "recycling" as used in the present invention means reusing and refilling a glass container as a container. This eliminates recycling the vessel through the molten glass.

In the present invention, reference to a range of x to y is intended to include the upper and lower limits of that range, equivalent to at least x and at most y.

In the present invention, the term "range between x and y" means that the upper and lower limits of the range are excluded, and is equivalent to more than x and less than y.

With regard to the method for treating glass containers according to the invention, it comprises the following steps:

i) cleaning by washing the glass container with a washing composition comprising a zinc or aluminium compound at a temperature of less than 90 ℃, and

ii) applying a coating on the surface of the glass container with a composition comprising a wax compound (W1).

Preferably, the cleaning step i) is performed before the coating step ii).

Preferably, the detergent composition is an aqueous composition.

Preferably, the detergent composition comprises an alkalinity source.

Preferably, the composition comprising the wax compound (W1) is an aqueous composition.

In addition, the method may optionally include other steps. An additional step may be iii) pasteurisation. Pasteurizing an already filled glass container, or pasteurizing a liquid filled into a container.

Pasteurization may be carried out by spraying the refilled containers with a hot water spray. The hot water spraying is carried out, for example, at about 65 ℃ for about 20 to 30 minutes. This can be done by tunnel pasteurization.

It is also possible to use an instantaneous pasteurization process, in which only the liquid filled into the container is pasteurized. For example, beer, fruit or vegetable juice, milk are pasteurized at 70 ℃ to 74 ℃ for 15 to 30 seconds and then filled into cleaned containers.

With regard to the cleaning or washing step according to the invention, it takes place at a temperature below 90 ℃. The temperature is the temperature of the cleaning composition. This temperature refers to the highest temperature during the entire washing step. The washing step may have sub-steps. In the present invention, this washing step is considered to be the cleaning or washing of the glass container with a washing composition. There may be an intermediate rinse step during the wash step that is below a specified temperature range or below a preferred minimum temperature. There may also be an intermediate rinse step between cleaning or washing the glass container with the wash composition during the wash step.

Preferably, the temperature of the washing step is below 88 ℃, more preferably below 86 ℃, still more preferably below 84 ℃, even more preferably below 82 ℃.

Preferably, the temperature of the washing step is higher than 40 ℃, more preferably higher than 50 ℃.

Preferably, the temperature of the washing step is between 40 ℃ and 88 ℃, more preferably between 50 ℃ and 86 ℃.

The washing composition for the cleaning step of the process of the invention is a zinc or aluminium compound and preferably the zinc or aluminium compound is in the form of a compound comprising zinc or aluminium ions. The source of aluminum ion and the source of zinc ion may be provided in the form of organic salts, inorganic salts, and mixtures thereof.

Exemplary zinc ion sources include zinc salts such as zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, zinc iodide, zinc thiocyanate, zinc fluorosilicate (fluorosilicate), zinc dichromate, zinc chlorate, sodium zincate, zinc gluconate, zinc acetate, zinc benzoate, zinc citrate, zinc lactate, zinc formate, zinc bromate, zinc bromide, zinc fluoride, zinc fluorosilicate (fluorosilicate), and zinc salicylate.

In a first preferred embodiment, the zinc salt is selected from the group consisting of zinc chloride, zinc bromide, zinc iodide, zinc sulfate, zinc nitrate and zinc acetate.

Exemplary sources of aluminum ion include aluminum salts such as sodium aluminate, aluminum bromide, aluminum chlorate, aluminum chloride, aluminum iodide, aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum formate, aluminum tartrate, aluminum lactate, aluminum oleate, aluminum bromate, aluminum borate, aluminum potassium sulfate, aluminum zinc sulfate, and aluminum phosphate.

In a first preferred embodiment, the detergent composition comprises a zinc compound.

In a second preferred embodiment, the cleaning composition comprises an aluminium compound.

In a third preferred embodiment, the cleaning composition comprises a zinc compound and an aluminum compound.

The amount of zinc or aluminium ions in the detergent composition is at least 0.00025 mol/l, preferably at least 0.0005 mol/l, more preferably at least 0.001 mol/l, still more preferably at least 0.002 mol/l, advantageously at least 0.005 mol/l and more advantageously at least 0.01 mol/l.

The amount of zinc or aluminium ions in the detergent composition is at most 0.1mol/l, preferably at most 0.05mol/l and more preferably at most 0.04 mol/l, still more preferably at most 0.03 mol/l, advantageously at most 0.025 mol/l and more advantageously at most 0.02 mol/l.

Preferably, the amount of zinc or aluminium ions in the detergent composition is between 0.00025 and 0.1mol/l, more preferably between 0.001 and 0.04 mol/l, still more preferably between 0.002 and 0.03 mol/l, advantageously between 0.005 and 0.025 mol/l and more advantageously between 0.01 and 0.02 mol/l.

Preferably, the pH of the detergent composition is at least 8. More preferably, the pH of the detergent composition is at least 12, still more preferably at least 12.5, advantageously at least 13, more advantageously at least 13.1 and most advantageously at least 13.2. Said pH of the detergent composition is obtained by adding at least one alkalinity source. The pH of the detergent composition was measured with a pH meter.

The cleaning composition comprises one or more alkalinity sources. The source of alkalinity may be selected from the group consisting of OH formation in aqueous solution^-An ionic compound. Preferably, the source of alkalinity is an alkali metal hydroxide. This may be, for example, sodium hydroxide or potassium hydroxide. The presence of hydroxide ions OH in the detergent composition^-。

OH in detergent compositions^-The amount of ions is at least 0.05mol/l, preferably at least 0.075mol/l, more preferably at least 0.1mol/l, still more preferably at least 0.15 mol/l and advantageously at least 0.2 mol/l.

OH in detergent compositions^-The amount of ions is at most 2.5mol/l, preferably at most 2 mol/l, still more preferably at most 1.5 mol/l and advantageously at most 1 mol/l.

Preferably, OH in the detergent composition^-The amount of ions is between 0.05 and 2.5mol/l, more preferably between 0.075 and 2 mol/l, still more preferably between 0.1 and 1.5 mol/l and advantageously between 0.2 and 1 mol/l.

Zinc or aluminium ions in detergent compositions and OH in detergent compositions^-The molar ratio between the ions is at least 0.002, preferably at least 0.0025, more preferably at least 0.003 and advantageously at least 0.005 and most advantageously at least 0.01.

Zinc or aluminium ions in detergent compositions and OH in detergent compositions^-The molar ratio between the ions is at most 0.5, preferably at most 0.4, more preferably at most 0.3, advantageously at most 0.2 and most advantageously at most 0.1.

Zinc or aluminium ions in detergent compositions and OH in detergent compositions^-The molar ratio between the ions is most advantageously between 0.01 and 0.10.

In one embodiment, the molar amount of zinc or aluminum ions in the detergent composition is related to the OH in the detergent composition^-The relationship of the ions is according to equation (1):

C₂=B*C₁+A （1）

wherein C is₂Is the concentration of zinc or aluminium ions in the detergent composition in mol/l, C₁Is OH^-The concentration of ions, in mol/l, B is the factor and A is the summand. The summand A is between-0.001 and 0.04. The factor B is between 0.025 and 0.045.

More preferably, formula (1) is especially suitable for OH groups of 0.05mol/l to 1mol/l^-Ion concentration interval and is advantageously applied to 0.1 to 1mol/l OH^-The ion concentration interval.

With regard to the coating layer application step according to the present invention, it is performed by bringing the coating composition into contact with the container by a coating layer application method. The method may be spray or dip coating, or use of a coating applicator.

The means for applying the coating by spraying comprises spraying means.

The device for applying a coating by dip coating comprises a reservoir containing a coating composition in which the container is immersed.

The coating applicator may be a brush, capillary, sponge, fiber, or the like. The coating is applied to the surface of the container via the contact area between the coating applicator and the surface of the container.

Preferably, the coating composition is applied by spraying.

Preferably, the composition is applied at a temperature below 60 ℃, more preferably below 50 ℃ and even more preferably below 45 ℃. In other words, the temperature of the glass container during step ii) is preferably below 60 ℃, more preferably below 50 ℃ and even more preferably below 45 ℃.

Although it is known from the prior art that glass bottle temperatures of 80 to 100 ℃ are required for rapid evaporation of the water of the composition, it has surprisingly been found that with the process of the present invention a composition comprising a wax compound (W1) can be attached to a glass bottle at temperatures below 60 ℃, in particular below 50 ℃.

The coating composition comprising the wax compound (W1) is preferably applied in the form of an aqueous dispersion. The dispersion comprises one or more surfactants and a wax compound (W1).

The dispersion according to the invention is a colloidal system at ambient temperature, having a continuous liquid phase and a discontinuous solid phase distributed throughout the continuous phase. Ambient temperature refers to the interval between 20 ℃ and 25 ℃. After application of the coating, the continuous liquid phase evaporates and the discontinuous solid phase forms the coating.

The surfactant may be nonionic, anionic, cationic, zwitterionic, or a mixture thereof.

Preferably, the surfactant comprises less than 20 wt% of anionic surfactant relative to the total weight of surfactant, preferably less than 10% of anionic surfactant relative to the total weight of surfactant, even more preferably without any anionic surfactant.

Preferably, the surfactant(s) are selected from the group consisting of nonionic, cationic, zwitterionic and mixtures thereof, preferably cationic surfactants.

Preferably, the coating composition applied on the surface of the glass container comprises one or more surfactants and a wax compound (W1).

The amount of the one or more surfactants in the coating composition is between 0.5 wt% and 50 wt% relative to a coating composition comprising the one or more surfactants and a wax compound (W1). In this calculation, only solid coating compositions, i.e. one or more surfactants and wax compounds (W1), are considered.

Preferably, the amount of surfactant(s) in the coating composition is between 5 and 50 wt.%, more preferably between 10 and 45 wt.%, still more preferably between 10 and 40 wt.%, even more preferably between 15 and 40 wt.%, advantageously between 20 and 40 wt.% and more advantageously between 20 and 40 wt.%.

Preferably, the aqueous dispersion applied on the surface of the glass container represents between 0.05% and 5% by weight of the coating composition according to the invention comprising the wax compound (W1).

Preferably, the aqueous dispersion applied on the surface of the glass container represents between 0.1 and 4 wt. -%, more preferably between 0.2 and 4 wt. -%, still more preferably between 0.5 and 4 wt. -% and even more preferably between 0.5 and 3.5 wt. -% of the coating composition according to the present invention comprising the wax compound (W1).

The coating composition comprising the wax compound (W1) applied as an aqueous dispersion on the surface of a glass container can be obtained by diluting a more concentrated dispersion.

The more concentrated aqueous dispersion comprising the wax compound (W1) has a solids content of between 5 and 50 wt. -%, based on the wax compound (W1) and the one or more surfactants.

Preferably, the more concentrated aqueous dispersion comprising the wax compound (W1) has a solids content of between 5 and 60 wt. -%, more preferably between 10 and 55 wt. -%, still more preferably between 10 and 50 wt. -% and even more preferably between 15 and 45 wt. -%, based on the wax compound (W1) and the one or more surfactants.

With respect to the wax compound (W1) of the coating application step of the process of the present invention, it is a low melting point wax as compared to the commonly used partially oxidized polyethylene wax. The wax compound (W1) may be pure or may be a mixture of wax compounds as long as the mixture has the melting point given below, and preferably has the melting point and saponification value given below.

The melting point of the wax compound (W1) is expressed as the drop melting point. The melting point was evaluated as the drop melting point according to ISO 6244: 1982. Preferably, the melting point of the wax compound (W1) is below 85 ℃. More preferably, the melting point of the wax compound (W1) is below 84 ℃, still more preferably below 83 ℃, even still more preferably below 82 ℃, advantageously below 81 ℃ and more advantageously below 80 ℃.

More preferably, the wax compound (W1) has a melting point above 60 ℃. Still more preferably, the wax compound (W1) has a melting point higher than 61 ℃, even still more preferably higher than 62 ℃, even still more preferably higher than 63 ℃, advantageously higher than 64 ℃ and more advantageously higher than 65 ℃.

More preferably, the wax compound (W1) has a melting point between 60 ℃ and 85 ℃. Still more preferably, the melting point of the wax is between 61 ℃ and 84 ℃, even more preferably between 62 ℃ and 83 ℃, even more preferably between 63 ℃ and 82 ℃, advantageously between 64 ℃ and 81 ℃ and more advantageously between 65 ℃ and 80 ℃.

The saponification number of the wax compound (W1) is higher than 20mg KOH/g. More preferably, the saponification number of the wax compound (W1) is higher than 25 mg KOH/g, still more preferably higher than 30 mg KOH/g, even still more preferably higher than 33 mg KOH/g, advantageously higher than 35 mg KOH/g and still more advantageously higher than 40 mg KOH/g.

The saponification number of the wax compound (W1) is less than 250 mg KOH/g. More preferably, the saponification number of the wax compound (W1) is lower than 225 mg KOH/g, still more preferably lower than 220 mg KOH/g, even still more preferably lower than 210 mg KOH/g, advantageously lower than 200 mg KOH/g and more advantageously lower than 190 mg KOH/g.

More preferably, the saponification value of the wax compound (W1) is between 20 and 250 mg KOH/g, still more preferably between 25 and 225 mg KOH/g, even still more preferably between 30 and 220 mg KOH/g, advantageously between 33 and 210 mg KOH/g, more advantageously between 35 and 200 mg KOH/g and even more advantageously between 40 and 200 mg KOH/g.

The acid number of the wax compound (W1) may be higher than 1 mg KOH/g. More preferably, the acid number of the wax compound (W1) is higher than 2mg KOH/g, still more preferably higher than 2.5 mg KOH/g, even more preferably higher than 3 mg KOH/g, advantageously higher than 3.5 mg KOH/g and more advantageously higher than 4 mg KOH/g. Acid numbers can be measured according to ASTM D1386 "Standard test method for Acid Number (Empirical) of Synthetic and Natural Waxes".

The acid value of the wax compound (W1) may be less than 25 mg KOH/g. More preferably, the acid number of the wax compound (W1) is below 24 mg KOH/g, still more preferably below 23 mg KOH/g, even still more preferably below 22 mg KOH/g, advantageously below 21 mg KOH/g and more advantageously below 20mg KOH/g.

More preferably, the acid number of the wax compound (W1) is between 2 and 24 mg KOH/g, still more preferably between 2.5 and 23 mg KOH/g, even still more preferably between 3 and 22 mg KOH/g, advantageously between 3.5 and 21 and more advantageously between 4 and 20mg KOH/g.

The wax compound (W1) may be made of natural wax or synthetic wax, or a mixture of both blended. Useful natural waxes include vegetable waxes, animal waxes, and mixtures thereof, so long as they have the desired melting point as defined above. Preferably, the wax compound (W1) has the desired melting point and saponification number as defined hereinbefore.

The wax compound (W1) according to the invention comprises at least 50 wt.%, preferably 51 wt.%, more preferably 52 wt.%, even more preferably 53 wt.%, advantageously 54 wt.% and more advantageously 55 wt.% of compounds comprising an ester function. The compound comprising an ester function or simply ester is preferably an organic ester. The organic ester is made from at least one alcohol and a fatty acid. The compound comprising an ester function may be a monoester, a diester, a triester, or mixtures thereof.

The alcohol of the organic ester may have one or more hydroxyl groups. Preferably, the alcohol of the organic ester is water soluble. By water-soluble is meant that the alcohol is completely miscible with water or that its solubility at 1013 mbar and 25 ℃ is greater than 0.005 mol/100g water. Preferably, the solubility is greater than 0.01 mol/100g water at 1013 mbar and 25 ℃, and more preferably the solubility is greater than 0.025 mol/100g water at 1013 mbar and 25 ℃.

Examples of alcohols in the present invention are methanol, ethanol, propanol, butanol; pentanol, hexanol; 1, 2-ethanediol; 1, 3-propanediol; 1, 2-propanediol; 1, 4-butanediol; 1, 2-butanediol; 1, 3-butanediol; 1, 5-pentanediol; 1, 2-pentanediol; 1, 3-pentanediol; 1, 6-hexanediol; diethylene glycol, triethylene glycol; glycerol or mixtures thereof, but not limited to this list.

The fatty acids are selected from long chain and very long chain hydrocarbon fatty acids. The hydrocarbon has at least 12 carbon atoms, preferably at least 14 carbon atoms. The hydrocarbon has up to 52 carbon atoms, preferably up to 50 carbons.

The hydrocarbon chain of the fatty acid may be a linear or branched alkyl, alkenyl group.

Examples of acids are lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, nacaric acid, stearic acid, nonadecylic acid, arachidic acid, heneicosylic acid, behenic acid, tricosylic acid, tetracosanoic acid, pentacosanoic acid, cerotic acid, montanic acid, nonacosanoic acid, melissic acid, hendecanoic acid, laccerotic acid, pediculosic acid, gemaric acid, triacontylic acid, hexacosanoic acid (ceroplastic acid), hexacosanoic acid (hexacosanoic acid), heptadecanoic acid, triacontanoic acid, myristoleic acid, palmitoleic acid, hexadecenoic acid, oleic acid, elaidic acid, octadecenoic acid, linoleic acid, trans-linoleic acid, alpha-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexanoic acid.

The organic ester of the wax compound (W1) made of at least one alcohol and a fatty acid may also be a mixture of different alcohols and fatty acids as listed above.

In a first embodiment, the wax compound (W1) is selected from a mixture comprising at least two compounds selected from organic esters, fatty acids and alcohols.

In one embodiment, the wax compound (W1) is selected from a mixture comprising at least two compounds selected from monoesters, diesters, triesters, hydroxyl monoesters, hydroxyl polyesters, acid esters, acid polyesters, hydrocarbons, fatty acids, fatty alcohols. Preferably, the ratio of free fatty acids and fatty alcohols in the wax compound (W1) is less than 80 wt%.

In another embodiment, the wax compound (W1) is selected from a mixture comprising at least two compounds selected from organic esters, hydrocarbons, fatty acids. Preferably, the ratio of free fatty acids in the wax compound (W1) is less than 80 wt.%.

In yet another embodiment, the wax compound (W1) is selected from a mixture comprising an aliphatic ester, an omega-hydroxycarboxylic acid, and a fatty alcohol. Preferably, the ratio of free fatty alcohol in the wax compound (W1) is less than 80 wt%.

In yet another embodiment, the wax compound (W1) is selected from a mixture comprising esters of diols and fatty acids. Preferably, the diol has less than 6 carbons.

All of the above embodiments of the wax compound (W1) comprise at least 50 wt% of the compound comprising an ester function as defined hereinbefore.

For all the above embodiments of the wax compound (W1), it has a melting point below 90 ℃, preferably below 85 ℃, and even more preferably below 83 ℃.

Since the wax compound (W1) having a melting point of less than 85 deg.C, preferably less than 83 deg.C may be a mixture, the melting point is not a single peak or point, but may be a range. However, the melting range is below the indicated melting point temperature.

More preferably, all of the above embodiments of the wax compound (W1) have a saponification number of the wax compound (W1) of higher than 20mg KOH/g.

Preferably, the wax compound (W1) has a melting point below 83 ℃ and a saponification number above 20mg KOH/g.

Optionally, the wax compound (W1) used in the present invention has a low penetration, low meaning that the penetration is less than 6 × 10^-1mm, advantageously less than 5 × 10^-1mm. The penetration may be evaluated according to ASTM D1321.

With regard to the glass container of the present invention, it is a bottle or a can. The bottle can be beer bottle, milk bottle or soft drink bottle, red wine bottle.

Preferably, the glass container is a recyclable glass container.

[ evaluation method ]

The Miele sterilizer model number G7835 CD was used as a washing machine. The effective wash time was 13.5 minutes and the total cycle time was 65 minutes. The washing temperature is between 60 ℃ and 80 ℃.

The line simulator used was a device from AGR International inc. Line simulations were performed under wet conditions at a speed of 30 rpm.

Pasteurization was carried out using a Miele sterilizer model number G7835, using the procedure 3-pateur, water temperature 65 ℃, total cycle time 40 minutes.

One cycle consisted of washing (alkaline washing), coating application, 1 minute line simulation, pasteurization, 1 minute line simulation, and the particular samples were measured after x cycles, in particular for measuring the slip angle, HEC thickness and burst pressure of the samples, and visual appearance of the containers.

The thickness of the Hot End Coating (HEC) was measured by a method that evaluated the amount of light reflection from the coated glass surface with a hot end coating measurement system from AGR International inc. Thickness is expressed as CTU (coating thickness unit; in SnO₂1 CTU = 0.25 nm).

The burst Pressure of the container was measured according to ASTM C147-86 (2015) using a Ramp Pressure Tester 2 from AGR International inc, where the Tester records the Pressure at which the bottle burst.

Slip angle was evaluated using a tilt test stand from AGR International inc. The tilt test stand measures the angle at which the bottle slides under contact with the same glass surface. This provides an assessment of surface lubricity. Three glass containers were placed on the test stand in a pyramid-like configuration. After pressing the start button, the motor increases the tilt angle of the test stand on which the pyramid of bottles is placed at a rate of 3.6 ° per second. The two bottles at the bottom are constrained from moving during testing. The top container is free to slide and when the angle of inclination is large enough to overcome the friction between the containers, the top container starts to slide and contacts the trip bar (trip bar). When the bottle depresses the trip lever, a switch in the electronic circuit of the tilt test stand opens, simultaneously stopping the drive motor and applying a brake to the tilt test stand. This feature prevents freewheeling (coasting) and accidental measurement of false high bank angles. The lubricity of the test container can be expressed by the angle at which sliding occurs or by the static coefficient of friction. Both measurements can be obtained from a scale in front of the test stand. If the sliding angle is less than 15 °, preferably less than 13 °, the bottle is considered to be sufficiently lubricated.

[ examples ]

A 50cl green glass or flint glass bottle was used as the container. The bottles have a tin oxide hot end coating. The initial HEC coating thickness according to the different test series had an initial thickness of 40 to 55 CTU. The bottles had the same initial coating thickness in each series. To compare the different series, the thickness was calculated as a relative value (in%) based on the initial coating thickness of each series.

The test series starts with a certain number of bottles, and after a certain washing cycle, the bottle or bottles are removed, dried if necessary and evaluated in the corresponding test.

Raw material

Using zinc (II) chloride (ZnCl)₂) As a zinc compound. ZnCl containing 0.22 wt.% during the cleaning step is used₂The solution of (1).

Sodium hydroxide (NaOH) was used as the alkaline source. An aqueous solution of 2 wt% NaOH was used during the cleaning step.

The following products were used as wax compounds (W1):

as wax compound (W1), herein referred to as (W1 a), candelilla wax is used having a melting point (range) of 68.5 ℃ to 72.5 ℃ and a saponification number of between 43 and 65 mg KOH/g.

A wax compound consisting essentially of a glycol ester of a C18-C36 acid having a melting point of 72.6 ℃ and a saponification number of 169 mg KOH/g, referred to herein as (W1 b), was used as the wax compound (W1).

As a comparative example, an oxidized polyethylene wax having a melting point (range) of 105 ℃ to 111 ℃ and a saponification value of less than 30 mg KOH/g, referred to herein as (C1), was used as a comparison.

Another comparative series was made by washing only the recycle vessel without applying a coating containing a wax compound.

The wax compound is applied in the form of a suspension by dipping the bottle into the suspension.

The results are summarized in tables 1 to 3.

TABLE 1 burst pressure results for comparative series without any wax compound coating and comparative series of comparative wax (C1)

。

Table 1 shows that the burst pressure drops significantly during the wash cycle, rapidly falling below 50% of the initial burst pressure.

TABLE 2 results with wax compound (W1 a)

。

Table 2 shows that HEC is maintained during the wash cycle and burst pressure is maintained at a satisfactory level until 25 recycle cycles.

TABLE 3 results with wax compound (W1 b)

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Table 3 shows that HEC is maintained during the wash cycle and burst pressure is maintained at a satisfactorily high level until 25 recycle cycles.