FIELD OF THE INVENTION

This invention relates to a coated paper wrapper to replace hot liquid form waxed wrappers such as those used for sticky candies and gum, comprising a functional, heat sealable, waterbased high-release grease, oil, water and water vapour transmission barrier coating composition on one or both surfaces of the paper substrate, and methods for manufacturing the coating composition and the coated paper wrapper. In particular, the coated paper wrapper and the process of manufacture excludes the use of a hot wax component.

BACKGROUND OF THE INVENTION

Manufacturing of the current hot wax wrapper for chewing gum and re-solubilised or high tack sugared candies involves up to three separate processes.

The first process includes, flexographic or gravure print application to the surface and reverse of a paper substrate. The second process involves suppling or re-moisturising of the paper substrate with chemicals to enhance the paper’s flexibility. This process involves the application of polyethylene glycol and/or glycerine, although is not limited to these chemicals to achieve the desired level of paper flexibility. Paper flexibility enhancement is necessary for wax wrappers to ensure that the wrapper, which becomes harder and less flexible through the application of wax, does not tear during forming and/or wrapping.

The third process involves the heating of solid blocks or granules of paraffin or other petroleum wax or modified wax blends (i.e. a hot wax component) at a high temperature in specialised wax bath containers. The high temperature is necessary to convert the wax from a solid to a heated liquid state and needs to be maintained accurately, as fluctuations in temperature can influence the wax viscosity and therefore the application grammages to the paper which will detrimentally influence the mechanical properties of the wax paper. The suppled paper is submerged into the wax bath and metered to ensure the paper is fully coated on one or both sides. Thereafter, the hot wax-impregnated paper requires cooling to re-solidify the waxed on exiting the heated wax bath/application system.

There are a number of problems associated with the use of a heated wax bath, including: the high temperature of the heated wax is a human health hazard, and can cause scalding burns to the skin which could result in disfigurement and/or permanent dammage to organs, skin and eyes; the requirement for high temperature wax baths results in a high energy requirement and hence a costly process for production of wax wrappers;

The transfer of heavy blocks of wax used in the process, if dropped on fingers or limbs, can cause bodily harm;

There are noxious fumes or gases produced during heating of the paraffin wax which requires the use of specialised respiratory equipment to ensure exhaust of paraffin gases into environment;

The noxious fumes or gases produced during heating are an environmental pollutant; hot wax is required to be applied at fairly high grammages in order to be effective, usually between 5 to 20 grams per square meter (g/m ² ) dry on each or single surface of the paper substrate, resulting in a relatively thick wrapper; the metering of applied hot wax to the paper substrate can be susceptible to inconsistency and is influenced by the temperature of the heated wax, which detrimentally affects the mechanical and release properties of the paper wrapper, the wrapper cost, wrapper yield and, volume of non-sustainable waste.

The multiple processes required to be used to produce a wax wrapper increases the complexity and time to produce the wrapping material. It would be useful if a coating formulation and method for a paper substrate could be developed to replace the time consuming and costly hot wax process for production of a coated wrapper for use with sugared candies that are sticky, gummy or tacky, including gum and the like.

A further disadvantage of the conventional hot waxed wrapper is that once the wrapped candy has been consumed, the wax wrapper is disposed of into the trash and destined for a landfill or is merely disposed of directly into the environment. Given that the conventional wax wrapper is non-disintegrating, non-bio-degradable and non-compostable waste and there are no “known” recovery or recycling methods for such hot waxed wrappers, these are not environmentally-“friendly” or “sustainable.”

For environmentally acceptable wrappers, some of the following measurments for disintegration, biodegradation and compostability should be met:

- Disintegration: the total wrapper should degrade, per conditions described in EN14045, to less than 10% of the original weight and residues should be approximately 2mm in diameter.

- Bio-Degradability: refers to the biological, aerobic, or anaerobic decomposition of the wrapping material into CO ² , water, and minerals. Importantly EN 14046 describes required biodegradability of 90% within 6 months, under specified conditions.

- Compostabilitv: refers to disintegration and biodegradability as described above and that the wrapping material should have no negative effect on the composting process as described in EN13432 and should not leave harmful residues behind.

Disintegration and decomposition can only occur if the waste is considered as food by microorganisms. All landfill environments are inherently occupied with specific microbes and enzymes, these organisms have adapted themselves to consume and breakdown trash. Unfortunately these micro-organisms, including aerobic and anaerobic bacteria do not recognise the chemical compounds in the standard hot waxed wrapper as organic food compounds, and therefore the standard hot waxed wrapper will not sustainably disintegrate or bio-degrade in the waste stream.

Natural disintegration of this wrapper can therefore only occur through sustained photodegradation. Photodegradation or photolysis, is the process by which the chemical bonds in the wax, over centuries of continuous exposure to the sun’s ultra violet (UV) rays, are broken down by photons in the UV spectrum. However, for sanitary reasons, landfills are covered daily with a layer of earth to reduce odours and so from a practical perspective, it is not possible to expose hot waxed wrappers to the sun.

In a landfill, the current hot waxed wrapper, in the absence of oxygen and water, is conservatively expected to require several centuries to disintegrate, based on respirometry tests. Respirometry tests are performed by placing solid wastes for testing e.g. fruit peels, paper board, various films and film/paper laminates, etc. in a vessel containing a specific microbe-rich compost and with aeration. Through microbe assimilation, generated CO ² levels serve as an indicator of degradation.

It would therefore be highly beneficial to develop a new candy wrapper for use with sticky, gummy or tacky sugared candies that is recyclable and repulpable and would sustainably degrade in the environment in a landfill.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a coated paper wrapper comprising or consisting of a print layer on one or both surfaces of a paper substrate and a water-based high-release grease, oil, water and water vapour transmission barrier coating over the print layer on one or both surfaces (i.e. the surface and/or the reverse), the barrier coating comprising or consisting of:

(i) an acrylic co-polymerized resin such as an OH-functional acrylate binder including a carboxy-functional styrene-acrylic resin, in particular a styrene-acrylic copolymer emulsified resin or a styrene-acrylic copolymer emulsified resin in combination with a styrene-acrylic copolymer resin solution;

(ii) a wax emulsion including any one or more of a polyethylene, paraffin, polypropylene, or carnauba wax emulsion, preferably a polyethylene/paraffin wax emulsion blend;

(iii) an antifoam such as an emulsion of a polyether siloxane copolymer which contains fumed silica; and

(iv) water, wherein the coated paper wrapper excludes a hot wax component.

The print layer may comprise or consist of one or more layers of print compositions and may include one or more of pearlised, white, pigmented, metallised, matt colour, or metallic surface prints or coating layers, as well as other suitable print finishes known to those skilled in the art.

In particular, the paper substrate may be paper, kraft paper or paperboard. In particular, the paper substrate may be uncoated, calendared or claycoated paper or paperboard.

In particular, the water-based high-release grease, oil, water and water vapour transmission barrier coating may comprise or consist of from about 73% to about 80% by volume of acrylic co-polymerized resin; from about 15% to about 16% by volume of wax emulsion; from about 3% to about 11 % by volume of water; and from about 0.7% to about 0.9% by volume of antifoam.

It is to be appreciated that the quantities set out above may include a variance of between about 2 to 5%, greater or lesser of each of the ingredients.

Optionally, additional additives may be included in the water-based high-release grease, oil, water and water vapour transmission barrier coating, such as one or more of emulsion stabilisers, lubricants, thickening agents, pigments, or crosslinking agents.

In particular, the coated paper wrapper may comprise or consist of the following layers in order from the outermost layer on a first surface of a paper substrate, to the outermost layer on a second surface of the paper substrate:

A. the water-based high-release grease, oil, water and water vapour transmission barrier coating of the invention;

B. a print composition layer;

C. the paper substrate;

D. optionally, a second print layer composition and/or the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention, wherein where both are present, either the optional second print composition layer or the water-based high-release grease, oil, water and water vapour transmission barrier coating of the invention is layered first.

In one exemplary embodiment, the coated paper wrapper may comprise or consist of the following grammages dry (grams per square meter (g/m ² ) as set out below of each of the coating composition layers: I. the high-release grease, oil, water and water vapour transmission barrier coating of the invention at between about 1 to 3 g/m ² , more preferably between about 1 to 2 g/m ² ;

II. the print composition at between about 1 to 2 g/m ² ;

III. the paper substrate at between about 25 to 40 g/m ² ;

IV. optionally a second print composition at between about 1 to 1 .5 g/m ² and/or a second layer of the high-release grease, oil, water and water vapour transmission barrier coating of the invention at between about 1 to 3 g/m ² , more preferably between about 1 to 2 g/m ² .

In particular the coating compositions preferably comprise the use of food safe compositions, including food safe print compositions comprising food safe inks or pigments.

According a second aspect of the invention there is provided a method for preparing a waterbased high-release grease, oil, water and water vapour transmission barrier coating composition wherein the method excludes the use of a hot wax component for production of the coated paper wrapper of the invention, comprising or consisting of the steps of:

(i) pre-mixing about 80 parts acrylic co-polymerized resin and about 1 part water in a first mixing vessel;

(ii) in a second mixing vessel, low shear mixing about 7 parts wax emulsion and about 1 .75 parts of water until blended;

(iii) adding the blended wax emulsion and water to the first mixing vessel and mixing until blended;

(iv) in a third mixing vessel, mixing about 0.7% to about 0.9% by volume of antifoam with about 0.45 parts water until blended; and

(v) adding the blended antifoam and water to the first mixing vessel and mixing until blended to form the high-release grease, oil, water and water vapour transmission barrier coating composition.

It is to be appreciated that the quantities set out above may include a variance of between about 2 to 5%, greater or lesser of each of the ingredients.

Additional water or water:95% ethyl alcohol at a ratio of 20:80 may be blended into the high- release grease, oil, water and water vapour transmission barrier coating after the last mixing step until a viscosity of about 20 to 30 seconds Zahn#2 at 25°C is achieved. Optionally, additional additives may be included in the water-based high-release grease, oil, water and water vapour transmission barrier coating composition, such as one or more of emulsion stabilisers, lubricants, thickening agents, pigments, or crosslinking agents.

Finally, according to a third aspect of the invention there is provided a method for manufacturing a barrier coated wrapper of the invention, wherein the barrier coated wrapper excludes a hot wax component, comprising or consisting of: a) application of a print layer composition to a first surface of a paper substrate; b) application of the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention over the print layer; c) optionally, application of a second print layer composition and/or the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention to a second surface of the paper substrate, wherein where both are present, either the optional second print composition layer or the water-based high-release grease, oil, water and water vapour transmission barrier coating of the invention is layered first.

In particular the paper substrate may be paper, kraft paper or paperboard. In particular, the paper substrate may be uncoated, calendared or claycoated paper or paperboard.

In particular, the method of manufacturing may comprise or consist of the following steps:

A. mixing each composition to ensure homogenisation prior to application to the paper substrate;

B. application of each of the composition layers to the paper substrate by any one or more coating techniques including gravure, flexographic, varnisher, roller coat, curtain, Meyer rod, dip or spray coating devices, preferably by flexographic or gravure application; and

C. drying the coated paper substrate after each application step by gas or electric fired ovens with high velocity air to remove the liquid solvents and ensure a tack free finish on delivery, typically at a temperature of between 70 to 100°C.

In one exemplary example, the method of manufacture comprises or consists of application of each composition to the paper substrate in the following order, with drying between each application: I. application of the print composition (1 to 2 g/m ² dry) to a first surface of the paper substrate;

II. application of the water-based high-release grease, oil, water and water vapour transmission barrier coating composition (1 to 2 g/m ² dry) of the invention;

III. optionally application of the second print composition (1 to 1.5 g/m ² dry) and/or the water-based high-release grease, oil, water and water vapour transmission barrier coating composition (1 to 2 g/m ² dry) of the invention to the second surface of the paper substrate, wherein where both are present, either the optional second print composition layer or the water-based high-release grease, oil, water and water vapour transmission barrier coating of the invention is layered first.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a coated paper wrapper to replace hot waxed wrappers such as those used for sticky candies, comprising a water-based high-release grease, oil, water and water vapour transmission barrier coating composition on one or both surfaces, and methods for manufacturing the coating composition and the coated paper wrapper. In particular, the process of manufacture and coated paper wrapper excludes the use of a hot wax component.

Unlike the conventional hot wax wrappers for use with sticky candy, the coated paper wrappers of the invention are recyclable and re-pulpable and will disintegrate in a landfill, therefore complying with the definition of “Upcycled Packaging™”, which means any packaging which has been re-designed in a qualified and measured way to: o reduce waste impact and or pollution; o be mechanically and chemically fit for purpose; and o be economically more viable due to reduced costs and/or more efficient production processes.

Furthermore, unlike the conventional hot wax wrappers, the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention is formulated for application to paper, over print, in a single flexographic or gravure process. This eliminates two separate processes required for hot wax wrapper production, namely suppling and waxing, as well as the associated toxic chemical inventories required for these processes.

The conversion of paper with the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention enables a functional and fit for purpose wrapper at a much lower wrapper grammage. The coating of the invention can be applied at between 1 g/m ² to 3.0 g/m ² dry, more preferably between 1 .5 g/m ² to 2.5 g/m ² dry, even more preferably between 1 .5 g/m ² to 2 g/m ² dry, over the paper substrate’s outer and inner surfaces, yet still achieves a fit for purpose coating, compared with 6 to 10 g/m ² in the case of hot wax wrappers and 2.5 g/m ² to 3 g/m ² dry in the case of the non-wax paper coating described in WO2014/172717. An advantage of the ability to use lower grammage, includes cost saving on materials (50 to 60% compared with hot wax).

Furthermore, the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention provides for faster evaporation , which allows faster drying, and this in turn allows an extension of print conversion speeds by gravure printing of up to 300 m/min, compared with the formulation described in WO2014/172717 which only achieves about 100 m/min to produce a fit for purpose final product with complete drying. Inadequately dried coating typically results in transfer of coating onto the press roller which affects print quality, results in lengthy press stoppages for clean-up and also can lead to block reels, which need to be disposed. The increased print application speed available with the formulation of the invention while still providing complete drying therefore reduces production costs. Additionally, it is possible use various method of printing, including flexographic and gravure printing for the formulation of the invention, whereas the formulation described in WO2014/172717 may only be effectively used with gravure printing.

The coated paper wrapper of the invention also provides a superior mechanical wrapping line speed of more than 1000 pieces of candy per minute, compared to only 800 - 1000 pieces per minute for the coated paper wrapper of WO2014/172717 (i.e. a >20% improved wrapping output).

Finally, the water-based high-release grease, oil, water and water vapour transmission barrier coating composition of the invention is advantagous over the formulation described in WO2014/172717, in that a single formulation is fit for purpose for use on both the first and second surfaces of the paper substrate, i.e. the inner surface of the wrapper which contacts the candy and the outer surface of the wrapper. Whereas, in the case of the formulation described in WO2014/172717, it is necessary to formulate the coating compositions for application to the inner and outer surface of the wrapper differently. This adds to the production complexity and cost of manufacture of the coated wrapper.

The invention will now be described with reference to the following exemplary embodiments which should in no way be considered to be limiting to the scope of the invention. EXAMPLES

1. Components of the water-based high-release barrier coated paper wrapper compositions

Table 1 - Hot Wax vs KandyKote® V8 wrapper construction

2. Water-based high-release grease, oil, water and water vapour transmission barrier coating compositions: KandyKote® V8

KandyKote® V8 is a new water-based high-release grease, oil, water and water vapour transmission barrier formulation recommended for application to paper wrappers to facilitate release from sticky candy such as gum.

KandyKote® V8 is applied to one or both paper surfaces (i.e. the surface and/or reverse), optionally over a print layer, typically at between 1 .5 - 2.0 g/m ² dry.

2.1. KandyKote® V8 Application Methodology

KandyKote® V8 can be applied through application processes such as gravure, flexographic, varnisher, rollercoat, semi- flexographic roll, blade coater or airknife coaters would be known to be useful to those skilled in the art.

As one example of an application methodology, direct gravure or rotogravure printing presses involves engraving or chemically etching micronized cells or wells over a chromed copperbased cylinder. These cells are specifically engraved or chemically etched to ensure specific cell dimensions and volumes. The unengraved or unetched areas of the cylinder represent the non-image areas. The cylinder rotates in a bath called an ink pan. As the cylinder turns, the engraved or etched cell volumes are filled with KandyKote® V8, the excess product is wiped off the cylinder by a flexible steel doctor blade. The remaining product in the recessed io cells forms the desired print or image by direct transfer to the paperboard substrate as the paperboard passes between the plate cylinder and the impression cylinder.

The coated paperboard subsequent to the transfer of the coating is drawn through gas or electric fired ovens, these ovens which are enclosed remove applied moisture and ensure the coating is dry before it reaches the next gravure station.

KandyKote® V8 is inline gravure applied at approximately 1 .5 to 2.0 g/m ² dry over paper or over print. It is to be appreciated that a person skilled in the art may modify the grammage to between 1 .0 to about 3 g/m ² dry depending on their requirements.

As a further example of application methodology, flexographic, or “Flexo” printing is a printing process which utilises a flexible relief plate, which is mounted over a roller. The plate is based on a light sensitive polymer. To create a specific image a negative image is placed over the plate, which is subsequently exposed to ultra violet light, the polymer hardens where light passes through the film, the remaining polymer which changes in consistency is washed away, this process can also be done by lazer etching. For full coverage, a standard rubber roller can be used instead of mounting a full plate.

The Flexo process involves a fountain roller which is submerged in the ink pan, this roller transfers the coating from the pan onto an anilox, which is also known as a metering roller.

The anilox roller, which has engraved recessed cells which are pre-determined to carry a specific volume of coating.

The doctor blade scrapes the anilox roll to ensure that the predetermined ink quantity delivered is only what is in the engraved cells, the coatings are transferred onto flexible printing plates or solid rubber roller as an alternative to a plate cylinder. The impression cylinder applies pressure to the plate cylinder, where the image is transferred to the paper substrate, the paper is drawn into an enclosed oven with heated air movement and the liquid carrier component from the coating is dried. Kandy Kote® V8, Formulation

Table 2 - KandyKote® V8 Formulation Description

KandyKote® V8, Process of manufacture

Equipment

Dedicated mixing vessels

Pre-blending vessels

Low shear blending equipment

Industrial weighing equipment

Personal protective equipment

Method

A. Pre-mix 80.00 parts styrene acrylic copolymer emulsified resin with 1 part water in a mixing vessel

B. Initiate / start up blending

C. Hand mix 16 parts wax emulsion with 1 .75 parts water, add to vessel

D. Hand mix 0.8 parts antifoam into 0.45 parts water, add to vessel and blend until mixed.

KandyKote® V8, Technical specifications

Product Description

KandyKote® V8 is specifically formulated for application to chewing gum paper as a replacement for hot waxed wrappers. It can be applied to the paper wrapper on either or both surfaces (i.e. the surface and/or reverse) of the paper to meet the mechanical demands of wrapping line forming and chewing gum protection. Product Features

- Excellent release from chewing gum candy

- Excellent water repellence

- Excellent heat abrasion tolerance

- Excellent heated forming jaw release

- Excellent moisture barrier

- Excellent flexibility

- Excellent deep freeze tolerance

- Exhibits customised tack seal integrity

- Imparts twist reflex hold

- Imparts suppleness to paper

- Imparts a low Coefficient of Friction (COF) to wrapper, which enables fit for purpose mechanical process stability at high wrapping line temperatures

- Imparts a soft bruise resistant finish

Typical Product Properties

Solid Content 33 - 38%

Package Viscosity 20 - 30" Zahn#2 @ 25°C

P.H. 8.0 - 8.5

Dry Coating Weight 1 .5 - 2.0 g/m ² dry, depending on requirements Reducer Water or water/Ethylol 95 [ 20:80, pre-blend ]

Wash Up Water, water/alcohol or Cleaner W6268

Additional Information

- Mix well before use

- Apply by gravure or Flexo coating, but can be customised for conversion through alternative print methods including but not limited to varnisher, roller coat, curtain coating devices, Meyer rod, dip and spray coating

- Remove dry coatings off rollers with cleaner or solvent

- High velocity warm air-drying

- Keep from freezing, store indoors between +5 °C to <+35 °C.