A METHOD FOR COATING A HOLLOW CONTAINER COMPRISING MOLDED PULP

Abstract

The present disclosure generally relates to a method for providing a barrier coating on a hollow container (100) comprising molded pulp. The method comprises providing a polymeric powder coating onto the interior surface (105a) and at least a portion of the exterior surface of the container (100) prior to curing and/or melting the powder coatings. The present disclosure also relates to a hollow container (100) formed by the method.

Claims

1. A method for providing a barrier coating on a hollow container (100) comprising molded pulp; said method comprising: a) providing a hollow container (100) comprising molded pulp, wherein said hollow container (100) comprises a main portion (101) and an upper portion (102); said hollow container extending along a longitudinal center line (103), wherein the longitudinal extension of said upper portion (102) corresponds to 5-30% of the maximum longitudinal extension of said hollow container (100), and wherein the longitudinal extension of said main portion (101) corresponds to 70-95% of the maximum longitudinal extension of said hollow container (100), wherein said hollow container comprises a bottom surface (104) and sidewalls (105) extending from said bottom surface (104) to an opening (106) of said hollow container; said sidewalls (105) and said bottom surface (104) defining an exterior surface and an interior surface (105a) of said hollow container; b) depositing a polymeric powder onto the interior surface (105a) of said hollow container (100) by means of a spraying device (107) capable of charging the polymeric powder prior to or during deposition of said polymeric powder, wherein at least said main portion (101) of said hollow container (100) is grounded during said polymeric powder deposition, c) depositing a polymeric powder onto the exterior surface of at least a portion of said upper portion (102) of said hollow container (100) by means of said spraying device (107), d) treating said hollow container with heat or irradiation under conditions that melt and/or cure said polymeric powder after said steps b) and c).

2. The method according to claim 1, wherein said hollow container has a moisture content of from 3 to 15% during said steps of polymeric powder deposition.

3. The method according to claim 1, wherein said polymeric powder deposition step b) is carried out in a molding device (108) comprising an electrically conductive material; said molding device (108) being configured to enclose at least a portion of said main portion (101) of said hollow container.

4. The method according to claim 3, wherein said molding device comprises a formable electrically conductive material.

5. The method according to claim 1, further comprising the step of: a) conditioning the hollow container at an ambient relative humidity of from 30 to 100%, after step a) of providing said hollow container comprising molded pulp.

6. The method according to claim 1, wherein said polymeric powder deposition steps b) and c) are performed simultaneously.

7. The method according to claim 1, wherein said polymeric powder deposition step c) is performed by arranging said spraying device (107) at a distance, d1, of from 10 mm to 250 mm, preferably of from 40 mm to 150 mm from said opening (106) of said container.

8. The method according to claim 3, wherein said molding device (108) comprises at least a first (108a) and a second (108b) removable portion, wherein said first removable portion (108a) is configured to enclose said upper portion (102) of said hollow container (100) and wherein said second removable portion (108b) is configured to enclose said main portion (101) of said hollow container (100).

9. The method according to claim 8, wherein said first removable portion (108a) is removed from said molding device (108) during said polymeric powder deposition step c).

10. The method according to claim 1, wherein said hollow container is a bottle, wherein said upper portion (102) comprises a shoulder portion (102a) and a neck portion (102b), wherein said neck portion has a smaller cross-sectional area than said main portion and is configured to circumferent at least said opening (106) of said bottle, and wherein said shoulder portion (102a) is arranged to taper between said main portion (101) and said neck portion (102b).

11. The method according to claim 10, wherein at least said neck portion (102b) of said upper portion (102) is coated in said polymeric powder deposition step c).

12. The method according to claim 10, wherein the entire upper portion (102) of said hollow container (100) is coated in said polymeric powder deposition step c).

13. The method according to claim 1, wherein said step d) is performed by heating said hollow container (100) at a temperature of from 120? C. to 220? C., for 1 to 30 minutes.

14. A hollow container (100) formed by the method according to claim 1, wherein the hollow container comprises a main portion (101) and an upper portion (102); said hollow container extending along a longitudinal center line (103), wherein the longitudinal extension of said upper portion (102) corresponds to 5-30% of the maximum longitudinal extension of said hollow container (100), and wherein the longitudinal extension of said main portion (101) corresponds to 70-95% of the maximum longitudinal extension of said hollow container (100), wherein said hollow container comprises a bottom surface (104) and sidewalls (105) extending from said bottom surface (104) to an opening (106) of said hollow container; said sidewalls (105) and said bottom surface (104) defining an exterior surface and an interior surface (105a) of said hollow container, wherein said hollow container comprises a barrier coating comprising polymeric powder on said interior surface (105a) of said hollow container and on the exterior surface of at least a portion of said upper portion (102) of said hollow container.

15. A hollow container according to claim 14, wherein said hollow container is a bottle; said upper portion (102) comprising a shoulder portion (102a) and a neck portion (102b), wherein said neck portion has a smaller cross-sectional area than said main portion and is configured to circumferent at least said opening (106) of said bottle, and wherein said shoulder portion is arranged to taper between said main portion and said neck portion, wherein said bottle comprises a barrier coating comprising polymeric powder on the interior surface (105a) of said bottle and on at least the exterior surface of said neck portion (102b) of said bottle.

16. A hollow container according to claim 14, wherein the thickness of the barrier coating is in the range of from 5 to 300 ?m, preferably from 20 to 100 ?m.

17. The hollow container according to claim 15, wherein the exterior surface of said main portion (101) of said bottle is void of a barrier coating comprising polymeric powder.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0072] The various aspects of the present disclosure, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

[0073] FIG. 1a schematically illustrates the step of providing an interior barrier coating according to an exemplary embodiment of the method of the present disclosure.

[0074] FIG. 1b schematically illustrates the step of providing an exterior barrier coating on the upper portion of a container according to an exemplary embodiment of the method of the present disclosure.

[0075] FIG. 2 schematically illustrates a bottle comprising molded pulp formed according to the method shown in FIGS. 1a-b.

[0076] FIG. 3a illustrates a bottle comprising molded pulp that has been coated according to the method of the present disclosure, wherein the bottle has been conditioned at a relative humidity of 90%.

[0077] FIG. 3b illustrates the bottle of FIG. 3a after heat treatment.

DETAILED DESCRIPTION

[0078] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the present disclosure to the skilled person. Like reference characters refer to like elements throughout.

[0079] In FIGS. 1a-b, a method for providing a barrier coating on a hollow container comprising molded pulp is conceptually illustrated. FIG. 2 illustrates a hollow container, i.e. a bottle, formed by the method of the present disclosure

[0080] The method of the present disclosure comprises: [0081] a) providing a hollow container 100 comprising molded pulp, wherein the hollow container comprises a main portion 101 and an upper portion 102; the hollow container extending along a longitudinal center line 103, wherein the longitudinal extension of the upper portion 102 corresponds to 5-30% of the maximum longitudinal extension of the hollow container and wherein the longitudinal extension of the main portion 101 corresponds to 70-95% of the maximum longitudinal extension of the hollow container, and wherein the hollow container comprises a bottom surface 104 and sidewalls 105 extending from the bottom surface to an opening of the hollow container; the sidewalls 105 and the bottom surface 104 defining an exterior surface and an interior surface 105a of the hollow container, [0082] b) depositing a polymeric powder onto the interior surface 105a of the hollow container 100 by means of a spraying device 107 capable of charging the polymeric powder prior to or during deposition of the polymeric powder, wherein at least the main portion 101 of the hollow container 100 is grounded during the polymeric powder deposition, [0083] c) depositing a polymeric powder onto the exterior surface of at least a portion of the upper portion 102 of the hollow container 100 by means of the spraying device 107, [0084] d) treating the hollow container with heat or irradiation under conditions that melt and/or cure the polymeric powder to form a barrier coating after steps b) and c).

[0085] As used herein, the term hollow container means any kind of container, such as a jar, tray, cup, bowl or a bottle. In the embodiments illustrated in the figures, the hollow container is a bottle. In embodiments, the hollow container has a rotational symmetry about the longitudinal center line. For example, the shape of the hollow container is generally cylindrical.

[0086] As used herein, the term molded pulp means a pulp or a pulp mixture that is shaped, pressed and dried. The molded pulp is may e.g. be made from paper or wood fibers. For example, the pulp may be a fibrous material produced by mechanically or chemically reducing woody plants to their component parts and then suspended in a fluid, e.g. water.

[0087] The interior surface of the hollow container is defined by the sidewalls and the bottom surface of the container. The interior surface may also be referred to as the interior walls.

[0088] The exterior surface is defined by the sidewalls and the bottom surface of the container. The exterior surface may also be referred to as the exterior walls.

[0089] The polymeric powder used for coating of the hollow container is not limited. For example, the powder may comprise a thermoplastic polymer selected from polyolefins, e.g. polyethylene or polypropylene and copolymers thereof, polyamides and polyesters, and copolymers thereof. The polymeric powder may also comprise water soluble synthetic polymers, such as polyvinyl alcohol or polysaccharides, such as cellulose. The powder particles typically have an average size in the range of 1 to 200 ?m, e.g. from 5 to 100 ?m, e.g. from 10 to 50 ?m. These ranges allow for an even coating, and furthermore allow for charging of the polymeric powder particles to be accomplished by the spraying device.

[0090] The longitudinal extension of the upper portion 102 corresponds to 5-30%, preferably 10-20% of the maximum longitudinal extension of the hollow container. The longitudinal extension of the upper portion is denoted e1 in FIG. 2.

[0091] The longitudinal extension of the main portion 101 corresponds to 70-95%, preferably 80-90% of the maximum longitudinal extension of the hollow container. The longitudinal extension of the main portion 101 is denoted e2 in FIG. 2.

[0092] A hollow container comprising molded pulp may be provided by means known to the skilled person. For example, the hollow container may be provided by depositing a pulp mixture into a mold, e.g. a split-mold, activating a pressing tool, e.g. an impermeable balloon within the interior cavity of the mold such that the pulp assumes the shape of the balloon, thereby forming the interior and exterior walls of the hollow container. The molded pulp may then be drained such that excessive water is removed. A process for providing a hollow container is e.g. described in WO16055073. Other means for providing a hollow container comprising molded pulp are also conceivable.

[0093] The hollow container may then be removed from the split-mold, and may be further conditioned prior to applying a powder coating onto the interior and exterior container walls.

[0094] In alternative embodiments, the step of providing a hollow container comprising molded pulp is achieved in the same molding device used for providing the interior and exterior coatings in steps b) and c) of the method.

[0095] As illustrated in FIGS. 1a-b, the spraying device 107 used for polymeric powder coating is a spray gun. The method is by no means limited to the use of a spray gun, but any spraying device capable of charging the powder prior to or during deposition of the powder can be used. The powder is typically charged by corona charging; i.e. the powder particles pass through a charged corona field at the tip or nozzle of the spray gun, which applies a negative (or positive) charge to each of the polymeric powder particles. This allows for the powder particles to strongly adhere to the grounded and electrically conductive parts of the hollow container and stick thereto.

[0096] As illustrated in FIGS. 1a-b, the spraying device 107 comprises a nozzle 107a that is inserted into the hollow container; i.e. into the bottle.

[0097] The hollow container may have a moisture content in of from 3 to 15%, e.g. from 5 to 10% during the steps of polymeric powder deposition.

[0098] The moisture content refers to the amount of water contained in the molded pulp container expressed as the percentage of the total weight of the molded pulp container. The moisture content is typically measured at a temperature of about 20? C.

[0099] With a moisture content in the above mentioned range, the polymeric powder has an enhanced tendency to adhere to the interior and the exterior surface of the hollow container.

[0100] The polymeric powder deposition step b) may be carried out in a molding device 108 comprising an electrically conductive material; the molding device 108 being configured to enclose at least a portion of the main portion of the hollow container.

[0101] In the method illustrated in FIGS. 1a-b, the polymeric powder deposition step b) is carried out in a molding device 108 comprising an electrically conductive material; the molding device 108 comprising at least a first 108a and a second 108b removable portion, wherein the first removable portion 108a is configured to enclose the upper portion 102 of the container and wherein at least the second removable portion 108b is configured to enclose the main portion 101 of the container.

[0102] In the embodiment illustrated in FIGS. 1a-b, the molding device 108 also comprises a third removable portion 108c. The first removable portion 108a is configured to enclose the upper portion 102 of the hollow container, and the second 108b and the third 108c removable portions are configured to enclose the main portion 101 of the hollow container.

[0103] The term enclose, in this context means that the removable mold portions surround and contact the hollow container portions such that an evenly grounded and electrically conductive surface is achieved. In embodiments, the respective removable mold portion has a shape that matches the shape of the hollow container portions.

[0104] The molding device 108 is configured to enclose the hollow container 100 to secure grounding and contact with an electrically conductive surface during polymeric powder deposition.

[0105] The molding device 108 may e.g. comprise a metal, such as aluminum.

[0106] In alternative embodiments, the molding device comprises a formable electrically conductive material.

[0107] The term formable means that the electrically conductive material of the molding device has the ability to conform or adapt to the shape of the hollow container when applying a moderate load. For example, the formable electrically conductive material may be an electrically conductive thermoplastic elastomeric co-polyester (TPC-ESD), an electrically conductive foam comprising e.g. polyurethane, an electrically conductive felt, such as a polyester fabric, or an electrically conductive rubber. The formable electrically conductive material may also be coated with a metal.

[0108] The inventors have found that by utilizing a formable molding device, a more even coating thickness is achieved. Furthermore, the deposition of the polymeric powder is less dependent on the moisture content of the hollow container. By utilizing a formable electrically conductive material, a moisture content in the range of from 3 to 10% may be utilized during the steps of polymeric powder deposition (steps b and c).

[0109] In embodiments where the molding device 108 comprises a metal, a moisture content in the range of from 8 to 15%, e.g. from 10 to 15% is typically utilized during the steps of polymeric powder deposition (steps b and c).

[0110] The method may further comprise the step of: [0111] a) conditioning the hollow container at an ambient relative humidity of from 30 to 100%, preferably from 30 to 70%, after step a) of providing a hollow container comprising molded pulp.

[0112] In embodiments, where the molding device comprises metal as the electrically conductive material, the method may further comprise the step of [0113] a) conditioning the hollow container at an ambient relative humidity of from 60 to 100%, e.g. from 75 to 95%, after step a) of providing a hollow container comprising molded pulp.

[0114] The polymeric powder deposition step b) is typically performed directly after the step a) of conditioning to maintain the moisture content of the hollow container during powder coating.

[0115] The conditioning time may be at least 2 hours, e.g. at least 10 hours, preferably at least 15 hours at an ambient relative humidity of from 60 to 100%, e.g. from 75 to 95%. The conditioning is typically performed at room temperature.

[0116] As illustrated in FIG. 1a, the main portion 101 and the upper portion 102 of the container are enclosed by the molding device 108 during the polymeric powder deposition step b).

[0117] The interior powder coating may be provided by continuously spraying the interior of the hollow container for about 1 to 20, e.g. 2 to 10 seconds. Charged particles are blown from the nozzle 107a towards the interior walls 105a of the container. An even electrical field is achieved by means of the molding device 108 enclosing the main and upper portions of the container. Accordingly, an even and uniform barrier coating covering substantially all parts of the interior walls of the container is achieved.

[0118] FIG. 1b illustrates the step of providing an exterior coating on the exterior surface of the upper portion 102 of the container 100. In this step, the first removable portion 108a is removed from the molding device 108.

[0119] The tip of the spraying device 107 is arranged at an axial distance, d1, of from 10 mm to 250 mm, preferably of from 40 mm to 150 mm from the opening of the container. Typically, spraying is achieved by arranging the tip or the nozzle of the spraying device 107 in a vertical position with respect to the center of the opening of the container; i.e. along the longitudinal center line.

[0120] The hollow container is preferably a bottle. As illustrated in FIG. 2, the bottle comprises a bottom surface 104 and sidewalls 105 extending from the bottom surface 104 to an opening 106 of the bottle; the sidewalls 105 defining the main portion 101 and the upper portion 102 of the bottle. The bottle may have a rotational symmetry about the longitudinal center line 103. The bottle typically has a substantially cylindrical shape.

[0121] The upper portion 102 comprises a shoulder portion 102a and a neck portion 102b, wherein the neck portion 102b has a smaller cross-sectional area than the main portion 101 and is configured to circumferent at least the opening 106 of the bottle, and wherein the shoulder portion 102a is arranged to taper between the main portion and the neck portion.

[0122] The shoulder portion typically tapers at an angle of from about 5 to 75 degrees, e.g. from 20 to 60 degrees between the main portion and the neck portion.

[0123] In the embodiment illustrated in FIG. 2, the neck portion 102b is threaded. A threaded neck portion may be beneficial in various bottle applications, but the present disclosure is not limited to the neck portion being threaded.

[0124] The neck portion 102b of the bottle is the portion subject to most moist and liquid. This portion is coated in the step c) of the method. The neck portion has a smaller cross-sectional area than the remaining parts of the upper portion 102 of the bottle.

[0125] In embodiments, where the neck portion 102b is threaded, the threaded portion typically has a trapezoidal configuration; i.e. a screw thread profile which enables a cap to be screwed thereto.

[0126] The main portion 101 and the upper portion 102 (comprising the neck portion and the shoulder portion) of the hollow container are formed integrally.

[0127] In the step of providing an exterior coating (step c), at least the neck portion 102b of the upper portion is coated.

[0128] After, the steps of polymeric powder deposition b) and c), the hollow container is subject to treatment with heat and/or irradiation under conditions that melt and/or cure the polymeric powder.

[0129] When the polymeric powder is exposed to elevated temperatures or to irradiation, e.g. ultraviolet radiation, the deposited polymeric powder coatings soften, melt and/or cure and a continuous barrier coating is provided.

[0130] Accordingly, a uniform barrier coating, free from pinholes is achieved.

[0131] Depending on the characteristics of the polymeric particles and the desirable thickness of barrier coating, the heat treatment step may vary.

[0132] In embodiments, the hollow container is subject to heat treatment at a temperature of from 100? C. to 300? C. The heat treatment time may be between 1 and 30 minutes.

[0133] Alternatively, the powder coatings may be treated with ultraviolet (UV) light, which typically allows for a fast melting and curing of the powder coating.

[0134] In exemplary embodiments, the curing step d) is performed by heating the hollow container at a temperature of from 120? C. to 220? C. during 1 to 30 minutes.

[0135] For example, the curing step may be performed by heating the hollow container at a temperature of from 150? C. to 200? C., preferably from 170? C. to 190? C. for 5 to 20 minutes, preferably from 6 to 15 minutes.

[0136] The method of the present disclosure allows for coating of both the interior surface and the exterior surface prior to heat (or irradiation) treatment. Accordingly, only one curing or melting step is required in the method. This is beneficial since the method is considerably simplified and saves time compared to if e.g. heating would have to be performed after the respective coating steps b) and c).

[0137] The step(s) of providing the interior and the exterior coatings in the same spraying sequence(s); i.e. prior to the heating or irradiating the polymeric powder coating may be connected to the moisture content of the hollow container. If the moisture content is higher, the exterior surface of the upper portion of the hollow container may be coated without connection to a grounded electrically conductive surface during the polymeric powder deposition. Depending on the material utilized as the electrically conductive material in the molding device, the moisture content may vary.

[0138] The method of the present disclosure is not limited to a particular pulp, but any pulp may be utilized.

[0139] In exemplary embodiments, the molded pulp is formed from a mixture of a first and a second pulp, wherein [0140] the first pulp comprises 65-90%, such as 70-84%, by dry weight of a first pulp having a Schopper-Riegler (SR) number according to ISO 5267-1 of below 48, preferably below 40, more preferably below 30; and [0141] the second pulp comprises 10-35%, such as 16-30%, by dry weight of a second pulp having a Schopper-Riegler (SR) number according to ISO 5267-1 of 60-90, preferably 70-90, more preferably 77-90.

[0142] Such a pulp mixture allows for an enhanced strength of the walls of the container and also affects how quickly the pulp can be dewatered in the mold. Accordingly, the step of providing a hollow container can be achieved in a quicker and more robust manner.

[0143] The first pulp may be unrefined or only modestly refined.

[0144] The second pulp typically has a higher degree of refining than the first pulp. Accordingly, the average fiber length is greater in the first pulp than in the second pulp.

[0145] The first and/or the second pulp may comprise market pulp; i.e. pulp produced in one location, dried and shipped to another location for further processing.

[0146] Preferably, at least 50%, e.g. at least 75%, e.g. at least 90% by dry weight of the first and/or second pulp is softwood pulp. Such pulp mixture allows for stronger container walls to be provided.

[0147] The thickness of the barrier coating formed by the method according to the present disclosure may be in the range of from 5 to 300 ?m, e.g. from 10 to 200 ?m, e.g. from 20 to 100 ?m.

[0148] The thickness of the barrier coating means the thickness of the cured barrier coating; i.e. the thickness of the coating after the hollow container has been treated with heat or irradiation under conditions that melt and/or cure the polymeric powder.

[0149] In another aspect, there is provided a hollow container, formed according to the method described hereinbefore.

[0150] With reference to FIG. 2, the hollow container comprises a main portion 101 and an upper portion 102; the hollow container extending along a longitudinal center line 103, wherein the longitudinal extension of the upper portion 102 corresponds to 5-30% of the maximum longitudinal extension of the hollow container 100, and wherein the longitudinal extension of the main portion 101 corresponds to 70-95% of the maximum longitudinal extension of the hollow container 100, wherein the hollow container comprises a bottom surface 104 and sidewalls 105 extending from the bottom surface 104 to an opening 106 of the hollow container; the sidewalls 105 and the bottom surface 104 defining an exterior surface and an interior surface 105a of the hollow container, wherein the hollow container comprises a barrier coating comprising polymeric powder on the interior surface 105a of the hollow container and on the exterior surface of at least a portion of the upper portion 102 of the hollow container.

[0151] Preferably, the hollow container is a bottle; the upper portion 102 comprising a shoulder portion 102a and a neck portion 102b; wherein the neck portion has a smaller cross-sectional area than the main portion and is configured to circumferent at least the opening 106 of the bottle, and wherein the shoulder portion is arranged to taper between the main portion and the neck portion; wherein the bottle comprises a barrier coating comprising polymeric powder on the interior surface 105a of the bottle and on at least the exterior surface of the neck portion 102b of the bottle.

[0152] The exterior surface of the main portion 101 of the bottle preferably does not comprise any barrier coating. In other words, the exterior surface of the main portion of the bottle is void of a barrier coating comprising polymeric powder. Accordingly, the main part of the exterior surface of the bottle will have a paper like appearance with no gloss.

Example 1: Powder Coating of the Interior and Exterior Surface of a Bottle Comprising Molded Pulp

[0153] The aim of the test was to apply a polymer powder coating to the interior surfaces of the bottle and the exterior surfaces of the upper portion; i.e. the neck portion, of the bottle prior to subjecting the coatings to heat treatment.

[0154] Three paper bottles were used in the testings. Each bottle comprised a pulp formed from a mixture of chemical and mechanical pulp.

[0155] The bottles were mounted in an aluminum molding device, hung upside down as illustrated in FIGS. 1a-b. The aluminium molding device comprised three removable portions. The spray gun used to deposit the powder coatings was a Nordson Encore HD automatic powder coating gun. The polymeric powder used was a HDPE powder with a particle size distribution of 0-80 um.

[0156] The spray gun nozzle was inserted in each bottle approximately 10 mm from the bottom surface of the bottle. The spraying sequence lasted for about 5-7 seconds, and was continuous while moving the spray gun out of the bottle.

[0157] Thereafter the portion of the molding device covering the upper portion of the bottle was removed, screw holes were covered and the bottles were sprayed once more by holding the spray gun about 100 mm from the bottle opening (see FIG. 1b). The adherence and coverage of the powder on the outside neck and shoulder of the bottles; i.e. the upper portion of the bottles were reported.

[0158] Three different bottles were used in the testings. Two bottles were conditioned at 23? C., 90% RH (moisture content of about 14%), overnight, and one bottle was conditioned at 23? C., 50% RH (moisture content of about 7%), overnight.

[0159] Bottles conditioned at 90% relative humidity (RH) had a very good coverage and the complete upper portion; i.e. neck portion, of the bottle exhibited an even exterior coating. The results are illustrated in FIGS. 3a and 3b. FIG. 3a illustrates the exterior coating 103 on the upper portion of the bottle 300. The main portion 101 of the bottle 300 does not have any coating on the exterior walls. FIG. 3a illustrates the bottle 300 after curing.

[0160] For the bottle cured at 50% RH, a smaller powder coverage of the exterior surface of the upper portion of the bottle was achieved.

Example 2: Powder Deposition Utilizing a Molding Device Comprising a Formable Electrically Conductive MaterialCoating Thickness on Sealing Area

[0161] The aim of the test was to, by the use of a formable molding device, apply a polymer powder coating on both the interior and exterior surface of the bottle at a lower moisture content than in Example 1. The molding device was made from electrically conductive thermoplastic elastomeric co-polyester in the shape of the bottle. When the bottle was placed in the molding device, approximately 15 mm of the neck area was uncovered, i.e. not in direct contact with the mold material making it possible to coat both the exterior and top surface of the bottle.

[0162] The spray gun used to deposit the powder coatings was a Nordson Encore HD automatic powder coating gun. The polymeric powder used was a HDPE powder with a particle size distribution of 0-100 ?m.

[0163] The bottles were mounted in the grounded formable molding device, hung upside down. The spray gun nozzle was positioned about 40 mm from the bottle entrance. The powder spraying started as the nozzle moved towards the bottle neck/bottle entrance. The nozzle kept spraying while traveling to about 10 mm from the bottom inside surface of the bottle were the spraying stopped. The nozzle then returned to its start position, about 40 mm from the bottle entrance, and stationarily sprayed the uncovered neck area of the bottle. The total spray time was 4 seconds.

[0164] A total of nine paper bottles were used during the test. Five of the bottles had a moisture content of 8.5% (measured at a temperature of about 20? C.) and four of the bottles had a moisture content of 5.2% (measured at a temperature of about 20? C.).

[0165] The bottles were sprayed according to above mentioned procedure and the coating weight was measured directly after. For the bottles with 8.5% moisture content, the average coating weight was 3.06 g (standard deviation of 0.07 g). For the bottles with 5.2% moisture content, the average coating weight was 3.24 g (standard deviation of 0.16 g).

[0166] After the coating weight had been measured, the bottles were placed in an oven at 180? C. for 10 min. The thickness of the coating layer around the circumference of the sealing area was then measured using an optical microscope.

[0167] The bottles with 8.5% moisture content had an average coating layer thickness on the sealing area of 103.6 ?m (standard deviation of 29.7 ?m). The total number of measurements were 219 positions on the sealing area of the five bottles. The bottles with 5.2% moisture content had an average coating layer thickness on the sealing area of 95.3 ?m (standard deviation of 28.5 ?m). The total number of measurements were 173 positions on the sealing area of the four bottles.

Example 3: Powder Deposition Utilizing a Molding Device Comprising a Formable Electrically Conductive MaterialCoating Thickness on Interior Bottle Surface

[0168] The aim of the test was to, by the use of a formable molding device and an optimized spraying sequence, apply a more even polymer powder coating on the interior surface of the bottle. The molding device was, as in example 2, made from electrically conductive thermoplastic elastomeric co-polyester in the shape of the bottle, with approximately 15 mm of the neck portion being uncovered.

[0169] For these trials the spray gun nozzle was initially positioned 10-15 mm from the bottom inside surface of the bottle. The powder spraying started as the nozzle started to move downwards towards the bottle neck/bottle entrance. The nozzle kept spraying while traveling to about 40 mm outside of the bottle entrance were the spraying stopped. The nozzle then remained stationary at this position and sprayed the bottle neck and threads. The total spraying time was 5 s.

[0170] A total of four bottles were used in the test, all with a moisture content of 5.2% (measured at a temperature of about 20? C.). The average coating weight was 3.48 g (standard deviation of 0.09 g).

[0171] The coating weight was measured directly after spraying, and the bottles were placed in an oven at 180? C. for 10 minutes. The thickness of the coating layer on the interior surface was then measured using an optical microscope by splitting the bottles in half and looking at the coating layer on the cut surface.

[0172] The average coating thickness in the bottles was 169.2 ?m (standard deviation of 49.9 ?m). The total number of measurements was 720 taken at different positions along the complete cut surface of all four bottles.

Example 4: Moisture Barrier Properties

[0173] The aim of the test was to evaluate the moisture barrier properties of bottles coated with the molding device comprising a formable electrically conductive material and spray sequences as described in Example 2.

[0174] A total of four paper bottles were used during the tests. The paper bottles were conditioned at 50% relative humidity (at 23? C.). The moisture content of the bottles (when applying the polymeric powder) was about 7% for all bottles. The average coating weight was 3.4 g (standard deviation of 0.1 g). After the coating weight had been measured, the bottles were placed in an oven at 180? C. for 6 min to melt the powder and form a continuous film. The moisture barrier properties of the bottles were then measured with Permatran. During the tests, the bottle necks were sealed onto a steel plate with epoxy resin. The average WVTR (23? C., 50% RH) was measured to 0.006 g/day and the average WVTR (38? C., 90% RH) to 0.04 g/day.

[0175] Accordingly, all four bottles displayed excellent moisture barrier properties.

[0176] Terms, definitions and embodiments of all aspects of the present disclosure apply mutatis mutandis to the other aspects of the present disclosure.

[0177] Even though the present disclosure has been described with reference to specific exemplifying embodiments thereof, many different alterations, modifications and the like will become apparent for those skilled in the art.

[0178] Variations to the disclosed embodiments can be understood and effected by the skilled addressee in practicing the present disclosure, from a study of the drawings, the disclosure, and the appended claims. Furthermore, in the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality.