SCRATCH MASKING COATING SOLUTION FOR GLASS CONTAINERS

The present invention relates to formulations for improving glass surface appearance, particularly the external surfaces of glass containers. More particularly, the present invention relates to a scratch masking coating solutions for glass bottles, which enhances appearance.

Glass articles such as returnable bottles are handled a great number of times during manufacture, inspection, filling, shipping, washing etc. During such handling the bottles come into contact with various mechanical devices such as conveyors, inspection devices and the like as well as contact with other glass containers (such as bottles, jars, and the like) and surfaces such as boxes, shelves etc. This high degree of contact causes damage either by breakage, cracking, scratching or other defects of the surface.

The use of scratch or scuff masking agents on glass containers is known. Such masking agents desirably mask scuffs, and exhibit an acceptable durability and surface properties. Desirable properties for scuff masking agents include water resistance and durability while being non-toxic and removable in alkaline bottle washing operations.

The variety of designs for glass bottle handling, cleaning and filling operations results in limitations on the applicability of prior art coating methods. Protective coatings are applied to glass containers in glass plant during manufacture in either a hot end process and/or cold end process. In single use glass containers, such protective coatings are sufficient to protect against scuffing during the life of the container.

With returnable glass containers, which can be washed and refilled, for example 20 to 60 times or more, the original protective coatings applied at the glass plant are washed off and protection is lost. As the number of return cycles increases, so does scuffing which results in an undesirable appearance.

Masking solutions may be used to improve the bottles appearance. Ideally, the masking solution should be food grade like, do not cause any skin irritation, and not aggressive against labels that are applied on the containers, which is not always the case. Furthermore, it was observed that some masking formulations, especially stored during warm conditions, show phase separation during storage. In case of phase separation of the formulation, the composition of the prepared coating solution will show high variation in concentration of the ingredients, this since small amounts from the bulk are mixed with solvent (water) used to prepare the coating solution from time to time. This will have a large impact on the effectiveness of the applied solution and will introduce a risk of producing non-sellable products due to no coating up to too high load of coating, which causes unacceptable touch and or appearance. Thus, there is a need for homogeneous formulations having good storage stability, food contact like and that shows homogeneity at storage. Nowadays, the commercial products do not fulfil all of these criteria.

Therefore, the main objectives of the present invention are to provide a stable formulation for the preparation of solutions to be applied on containers, and in particular to be applied on returnable containers, in order to face-lift or mask the white reflecting bands (scuff bands) that appear at the container-to-container (or other container to devices or surfaces) contact zones, because of intense glass to glass contact (or glass to devices and the like, as explained above), mainly during the filling process, after several trips of returnable glass containers.

Another objective of the present invention is to provide a coating process comprising a step a) of applying the solution as defined above, to a glass container surface, such as bottles. Said process permits to repair the visual aspect of such containers, since the presence of scuff bands badly reduces the appearance of containers.

It has now surprisingly been found that the above objectives are met, in whole or in part, with the use of the particular formulations of the present invention, which are now described in more details below.

By saying that a range is“from x to y” or“x to y” in the present invention, it is meant that the upper and lower limit of this range are included, equivalent to at least x and up to y.

Therefore, the present invention relates to an improved formulation and an improved process for masking containers.

According to a first aspect, the present invention relates to a formulation comprising:

- at least a mineral oil; - at least a sorbitan ester;

- 2 wt% to 20 wt% of water, hydrogen peroxide or a mixture thereof, preferably more than 3 wt% to 20 wt% of water, hydrogen peroxide or a mixture thereof, relative to the sorbitan ester weight, said water optionally comprising up to 30wt% of hydrogen peroxide relative to the water content.

By“mineral oil” it is understood one or more alkanes (alphatic and/or cyclic) from mineral source, particularly from a distillate of petroleum. Mineral oil can be the product of refining crude oil and can also be extracted from coal, wood and oilshale. Preferred mineral oils are saturated C8-C22-hydrocarbons, which are linear or branched or naphthenic oil. Especially preferred are saturated C8-C14- hydrocarbons.

The mineral oil of the invention can be liquid at temperature above -5°C, more preferably at a temperature above 0°C, and even more preferably at a temperature above 10°C.

Preferably, the mineral oil is colourless.

Preferably, the mineral oil is odourless, and more preferably is colourless and odourless.

Preferably, the mineral oil of the invention are classified as E 905a as defined by the Regulation (EC) No 1333/2008 of the European Parliament and the Council of 16 December 2008 on food additives.

Preferably, the mineral oil has a viscosity of less than 100 mPa.s, preferably of less than 50 mPa.s at 20°C. Low viscosity is preferred since the mobility on the glass surface is limited in case of high viscosity. Furthermore, high viscosity results in a more fatty touch.

The viscosity can be measured at a temperature of 20°C, with a shear rate of 1000 s ¹ with a Brookfield viscometer equipped with a rotor.

Preferably, the mineral oil has a flash point higher than 150°C, more preferably higher than 160°C, and even more preferably higher than 175°C for safety issues. Preferably, the at least one mineral oil is chosen in the group consisting of: Catenex T121 (supplier: Shell), Sipmed 20 (supplier: SIP), Pioneer 2055 (supplier: Klaus Dahleke), Purity base oil 1020 (supplier: Petro Canada), Puretol 1 1 D (supplier: Petro Canada), Blandol XT (supplier: Sonneborn) and mixture thereof. Preferably, the formulation comprises 75 to 94 wt% of mineral oil, preferably from 80 to 90 wt% based on the formulation weight.

Preferably, the at least one sorbitan ester, alkoxylated or not, is chosen in the group consisting of sorbitan monostearate, sorbitan tristearate, sorbitan monolaurate, ethoxylated sorbitan ester (polysorbate), propoxylated sorbitan ester, sorbitan monooleate and combinations thereof. Preferably, the at least one sorbitan ester is a mono oleate, alone or with at least one other sorbitan ester.

Since the formulations are used in the present invention for coating of glass containers in the food and beverage industry, the surfactant(s) are preferably chosen from among the group of sorbitan esters listed in the European food additive list E numbers, sections E491 to E496.

Preferably, the sorbitan ester is alkoxylated, more preferably is ethoxylated and/or propoxylated and even more preferably is an ethoxylated sorbitan ester.

Preferably, the at least one ethoxylated sorbitan ester is chosen in the group consisting of ethoxylated sorbitan monostearate, ethoxylated sorbitan tristearate, ethoxylated sorbitan monolaurate, ethoxylated sorbitan ester (polysorbate), ethoxylated propoxylated sorbitan ester, ethoxylated sorbitan monooleate ester and combinations thereof. Preferably, the at least one sorbitan ethoxylated ester is an ethoxylated monooleate, alone or with at least one other sorbitan ester, alkoxylated or not.

Preferably, the sorbitan is chosen in the group consisting of:

- Sorbitan Mono Oleate 5EO (SMO-5EO)

- a mixture of Sorbitan Mono Oleate (SMO) and Sorbitan Mono Oleate 20EO (SMO-20EO),

- or a mixture thereof.

Sorbitan Mono Oleate 5EO (SMO-5EO) is particularly preferred.

Sorbitan Mono Oleate 5EO (SMO-5EO) is commercially available as SURFALINE SE81® (from Arkema).

Sorbitan Mono Oleate (SMO) is commercially available as Span 80® (from Croda). Sorbitan Mono Oleate 20EO (SMO-20EO) is commercially available as SURFALINE SE80® (from Arkema) or Tween 80® (from Croda). The mixture of Sorbitan Mono Oleate and Sorbitan Mono Oleate 20EO preferably comprises from 35 to 60wt% of Sorbitan Mono Oleate and 40 to 65wt% of Sorbitan Mono Oleate 20EO relative to the total weight of the mixture, preferably from 40 to 55wt% of Sorbitan Mono Oleate and 45 to 60wt% of Sorbitan Mono Oleate 20EO relative to the total weight of the mixture, and even more preferably from 45 to 50wt% of Sorbitan Mono Oleate and 50 to 55wt% of Sorbitan Mono Oleate 20EO relative to the total weight of the mixture.

Preferably, the at least one sorbitan ester has a HLB from 8 to 12, preferably from 9 to 1 1 , and even more preferably from 9.5 to 10.5. When the formulation comprises more than one surfactant, it should be understood that the total of surfactants should have a HLB from 8 to 12, preferably from 9 to 1 1 , and even more preferably from 9.5 to 10.5.

Preferably, the formulation comprises 6 to 20 wt% of sorbitan ester, preferably 10 to 20 wt% based on the formulation weight.

Preferably, the formulation of the invention comprises 2 wt% to 20 wt% of water, preferably more than 3 wt% to 20 wt% of water relative to the sorbitan ester weight, said water optionally comprising up to 30wt% of hydrogen peroxide relative to the water content.

Preferably, the formulation of the invention comprises 2 wt% to 20 wt% of water, preferably more than 3 wt% to 20 wt% of water relative to the sorbitan ester weight. The formulation of the invention comprises 0,12 wt% to 4 wt% of water, preferably more than 0,18wt% to 4 wt% of water relative to total weight of the formulation, said water optionally comprising up to 30wt% of hydrogen peroxide relative to the water content.

When the water comprises hydrogen peroxide, the content of hydrogen is preferably up to 30wt% relative to the water content, more preferably the content of hydrogen is preferably up to 20wt% relative to the water content.

Water is particularly preferred.

Preferably, the water is demineralized water.

Alternatively, hydrogen peroxide is used, which permits to avoid coloration of the solution.

Advantageously, the hydrogen peroxide of the invention is in a liquid form. In particular, the formulation of the invention comprises:

- at least one mineral oil having a viscosity of less than 100 mPa.s, preferably of less than 50 mPa.s at 20°C;

- at least a sorbitan ester chosen in the group consisting of:

- Sorbitan Mono Oleate 5EO (SMO-5EO)

- a mixture of Sorbitan Mono Oleate and Sorbitan Mono Oleate 20EO,

- or a mixture thereof

- 2 wt% to 20 wt% of water, preferably more than 3% up to 20% of water, relative to the sorbitan ester.

A particularly preferred formulation of the invention comprises:

- 75 wt% to 94 wt%, preferably from 80 to 90 wt% of at least one mineral oil having a viscosity of less than 100 mPa.s, preferably of less than 50 mPa.s at 20°C, relative to the formulation weight;

- 6 wt% to 20 wt%, preferably 10-20 wt% based on the formulation weight of a sorbitan ester chosen in the group consisting of:

- Sorbitan Mono Oleate 5EO (SMO-5EO)

- a mixture of Sorbitan Mono Oleate and Sorbitan Mono Oleate 20EO,

- or a mixture thereof

- 2 wt% to 20 wt% of water, preferably more than 3 wt% to 20 wt% of water, relative to the sorbitan ester.

The formulation of the invention can comprise one or more additional additives, preferably chosen in the group consisting of biocides, bactericides, preservatives, ester alcohol, glycol ether, dyes, emulsion destabilizers, perfumes, odorants, UV absorbers, light absorbers, impact absorbers, surfactants other than sorbitan esters, oils other than mineral oils and the like.

Preferably, the additional additive does not impact the homogeneity of the solution. Such additives may be added in the formulation and/or in the ready-to-use coating solution and/or in the aqueous phase or water used for forming the coating solution. According to a preferred embodiment, the formulation for use in the present invention does not contain any additive, and preferably consists in a mixture of at least one mineral oil, at least one sorbitan ester such as those described above and water.

Preferably, the mineral oil of the invention and the sorbitan ester are miscible the one in the other.

Moreover, preferred formulations are liquid formulations, solid formulations being not convenient as scratch-masking coatings.

The present invention is also relative to a process of preparation of the formulation as defined above, comprising a step of mixing at least one oil as defined above, at least one surfactant as defined above and water as defined above, in any order, to obtain the formulation.

Preferably, the formulation of the invention is used to prepare a coating solution (also named a coating dilution), which is preferably an emulsion. Thus, according to another aspect, the present invention is relative to the use of the formulation according to any of the preceding claims, for the preparation of a coating solution. The present invention also relates to a coating solution comprising the formulation as defined above.

Said coating solution may contain polyethylene glycol, alcohol, ether, glycol ether, polyether and mixtures thereof.

Preferably, the coating solution is in the form of an oil-in-water emulsion, wherein the oil phase comprises, preferably consists of the formulation as defined above.

In the present invention, the “oil-in-water emulsion” is understood as a water continuous phase having dispersed or emulsified therein an oil phase, wherein the oil phase comprises the formulation of the invention.

The coating solution is typically prepared by mixing the formulation as defined above with an aqueous phase.

Preferably, the aqueous phase is water.

The formulation of the invention can be supplied as a concentrate to be mixed with the aqueous phase by the end user to form the coating solution (preferably an emulsion) or supplied as a ready-to-use coating solution (already prepared by mixing it with an aqueous phase). Thus, the present invention is also relative to a process of preparation of the coating solution, comprising a step of mixing the formulation as defined above with an aqueous phase, preferably with water.

The present invention also encompasses coating solutions prepared by mixing water and at least one of the above-defined surfactants, then adding and mixing at least one of the above-defined oils, or prepared by mixing water and at least one of the above-defined oils, then adding and mixing at least one of the above-defined surfactants.

In other words, the coating solution to be applied on the glass surface may be prepared by mixing at least one oil, at least one surfactant and water, in any order, so as to obtain the coating solution. Thus, the present invention is also relative to a process of preparation of the coating solution, comprising a step of mixing at least one oil, at least one surfactant and water, in any order, to obtain the coating solution. The preferred concentration of the formulation (oil phase) in the coating solution is from about 2% to 20% by weight, preferably from about 3% to 10% by weight, more preferably from 3% to 8% by weight of the total weight of the coating solution. When the coating solution is an oil-in-water emulsion, the mixing energy devoted to the preparation of the above described oil-in-water emulsion should be set so that the emulsion is stable for a period time ranging from a few seconds to a few hours, and preferably for period of time that is adapted so as to supply a homogenous working liquid to the applicator. This period of time therefore depends on the flow lines, application devices, and the like.

By“stable emulsion for a period of time” is meant that no macroscopic phase separation (nearly complete breaking of the emulsion) occurs between the oil and the water during the time ranging from a few seconds to a few hours and preferably for period of time that is adapted so as to supply a homogenous working liquid to the applicator. The emulsion of the invention has a limited stability meaning that the emulsion will break on a time scale much longer than a few hours and preferably after a period of time that is adapted to supply a homogenous working liquid to the applicator. However, a slight coalescence of the oil drops or a slight flocculation or a slight creaming might already have begun on a microscopic level during the period of time ranging from a few seconds to a few hours and during the period of time that is adapted so as to supply a still homogenous working liquid to the applicator.

Any mixing means may be used to achieve an oil-in water-emulsion from water and the above-described formulation. Typical mixers or emulsifying devices are those known in the art, and as non-limiting examples, mention may be made of dynamic mixers, static mixers, ultra-sonic mixing devices, pumps, and the like.

According to a further aspect, the present invention pertains to the use of the formulation or the coating solution as defined above, as a scratch-masking coating on a glass surface.

According to a further aspect, the present invention pertains to a coating process comprising a step a) of applying the formulation or the coating solution as defined above, preferably the coating solution as defined above, to a glass surface.

The coating process of the invention permits to mask scratches and abrasions on a glass surface, especially on a glass container surface, which adversely impact its commercial value. For examples, scratches or abrasions on glass bottles, especially on returnable glass bottles used for beverages, result in an undesirable haze or white appearance, which decreases the value of the bottle. The process of the present invention provides a coating for glass containers that masks such scratches or abrasions.

The glass surface is preferably a glass container surface, and more preferably is a returnable glass bottle.

The emulsion, i.e. the formulation of the invention or the coating solution of the invention may be applied via a method chosen in the group consisting of spraying, dipping or any other contact method (sponge, and the like). Spray application is preferred.

In other words, the coating applicator can be a brush, capillary, sponge, fibre or the like. In this case, the coating material is applied on the surface of the container via the contact area between the coating applicator and container surface.

Preferably, during step a) glass containers are at ambient temperature, i.e. at temperature from 5 to 40°C. The emulsion is applied on the outer surface of the glass container.

The emulsion can be applied onto at least one part of, or onto the entire, outer surface of said glass container.

When the process is used for coating a glass container, it can further comprise at least one, preferably 2, more preferably 3, more preferably 4, and even more preferably all the following steps before step a):

1 ) preparing a formulation or a coating solution as defined above;

2) washing the glass container to be coated;

3) applying a lubricant onto one or several parts of, or else on the whole outer surface of said glass container;

4) filling and capping the glass container; and

5) labelling the glass container.

If at least 2 steps are performed, they are preferably carried out in the order indicated above (from 1 to 5).

The washing of the glass container may be carried out according to any method well known in the art, and for example using water, preferably hot water. Said water can contain one or more detergent, for example a base, such as sodium hydroxide.

At least one lubricant can also be applied onto the outer surface of the glass container after washing. Such lubricants are known in the field, such as for example Kercoat® 500 provided by Arkema.

The glass containers are then filled and capped, again according to known methods, with cold, tepid or warm liquids, preferably warm liquids.

Labelling may be realised before or after step a).

The labelling step can therefore be realised before the scratch-masking coating step.

Step a) may be the last step before the newly washed, refilled and labelled glass containers are once again put on the market, and sold to the customers.

No specific equipment is required for carrying out the process of the invention, this meaning that any and all known equipments in the art are convenient for the use and process of the invention.

The application equipment typically includes mixing and storage vessels, pumps, transfer and feed lines, spray apparatus and control and monitoring equipment. Preferably, the equipment comprises one or more mixing vessel(s); dosing and circulating pump(s); mixing unit (can be the pump itself); circulation piping(s); applying means, such as spraying devices; and the like.

The equipment may also comprise controlling means aiming at monitoring the process of applying the scratch-masking emulsion. Such controlling means may be for example optical means detecting the presence or the absence of a container in front of the applying means, and/or detecting the presence and the quantity of scuff bands or scratches, so that the minimum amount of emulsion is applied on the containers to obtain the best efficiency. According to a preferred aspect, the controlling means are monitored via a computer that may interact with the dosing pump(s) and applying means.

Still according to a preferred embodiment, the above-described equipment may be encased within a“scratch-masking” cabinet that can be easily adapted to existing bottling lines, comprising the necessary equipment for washing, filling, capping and labelling glass containers, typically returnable glass bottles.

The present invention is also relative to a glass surface, preferably a glass container, and even more preferably a glass bottle obtainable by the process of the invention. The glass surface obtainable by the process of the invention provides good masking properties, improves the touch experience (especially lowered chance of fatty touch when applied in excess) and shows no label sensitivity, i.e. there is no extraction of the dye from print and no deformation of the label.

The present invention is illustrated in more detail in the following non-limiting examples.

Examples

The following examples are carried as described below:

Fixed parameters are the following:

- Mixing conditions, power and mixing time;

- Bottle conditions;

- Spray conditions, spray volume, sp. ray tool conditions; - Water quality for dilution of the coating solution;

- Storage conditions.

More precisely:

- Concentration (wt)% of formulation in the aqueous coating solution 5.0 - 7.5;

- Water hardness 3 °DH;

- Bottle temperature 20 °C;

- Spray amount per bottle 0.5 ml_ per bottles (upper scuff band only);

- Storage conditions : room conditions, 1 hour;

- Mixing means : Dispermat ^® , continuous at 20 % stirring power, 5 minutes.

The various formulations are applied with the following conditions:

- Application gun : Air guided spray (P guide air = 2 bar, P spray =

1 .5 bar);

- Spray pattern : horizontal;

- Spray volume : 0.5 ml_, directed to shoulder scuff band only;

- Bottle rotation : ± 30 rpm;

- Bottle type : Coca Cola ^® 25 cL;

- Number of bottles : 5.

1) Improved properties of the composition of the invention

- The tested composition were:

- Composition A: Opticoat® 140

- Composition 1 (according to the invention): 84wt% Blandol XT, 15wt% Surfaline SE-81 and 1wt% water

1 .a. Coating performances

The bottles are checked for assessing the scratch-masking efficacy, 24 hours after application, by visual observation of the bottle shoulder scuff band. For each bottle, a note is given, from 0 to 5: - For the masking efficiency“0” means no coating and“5” means 100% masked;

- For the touch experience,“0” means fatty appearance with droplets visible and“5” pleasant, glass like appearance.

The results are the sum of the notes obtained for 3 coated bottles and are presented in Table 1 below.

[Table 1 ]

These results show that the composition of the invention provides better masking properties that the commercial compositions and, improve the touch experience (especially lowered chance of fatty touch when applied in excess).

1.b. Label sensitivity:

AMSTEL® BEER labels were put between filter paper and saturated with 10(w)% of the compositions A and 1. The wet labels between filter paper are hold between two glass sheets for 24 hours.

For each bottle, a note is given, from 0 to 5:

- For the smear,“5” means no smear and“0” means high smear. - For the ghost,“5” means no ghost print and“0” means intense ghost print.

The results are presented in table 2 below: [Table 2 ]

2) Stability with Blandol XT The following compositions were prepared as described above and were tested for their stability, at room conditions, 40°C and 0°C.

The results are presented in Tables 3 and 4 below.

[Table 3]

[Table 4]

These results shows that the compositions of the invention do not present phase separation at room conditions, 40°C and 0°C.

3) Stability with other oils

The same experiments was repeated with other oils:

Compositions comprising 85wt% of oil, 15 wt% of SURFALINE SE81 and 1 % of water were prepared as described before.

The following oils were tested: [Table 5]

No separation was observed at room conditions, 0°C and 40°C, except for the Parol oil, which has a viscosity of 170 mPa.s., where a phase separation was observed for all the temperatures.

4) Compositions comprising hydrogen peroxide

Examples 1 and 2 were reproduced, but water was replaced by hydrogen peroxide in the compositions 1 to 8. Similar results to those of examples 1 and 2 were obtained.