Paperboard-based disposable cups with a low PPS inner layer

Abstract

The present invention relates to a paperboard-based disposable cup, the paperboard-based disposable cup being formed of a paperboard-based laminate, and a first surface of the paperboard-based laminate forming the inner surface of the paperboard-based disposable cup has a basis weight of 10 to 20 g / m 2 and a pigment coating layer with a basis weight of 5 to 25 g / m 2 and an outermost polymer coating layer in the range of 0.1 μm to 1.5 μm, and the interior surface of the paperboard based disposable cup has a PPS surface smoothness of <3 μm as determined in accordance with ISO 8791-4:2007.

Description

[Technical Field]

[0001] The present disclosure relates to a paperboard-based disposable cup, and more particularly to a paperboard-based disposable beverage cup suitable for serving beer. [Background technology]

[0002] At large events such as outdoor festivals, beer is commonly served in disposable plastic cups. However, due to environmental concerns and legislative changes, there is strong pressure to reduce the use of disposable plastic products. However, the potential for paperboard-based cups to replace plastic beer cups is limited due to the problem of excessive foaming in current paperboard-based cups.

[0003] Coating paper and paperboard with plastics is often used to combine the mechanical properties of paperboard with the barrier and sealing properties of plastic films. Paperboard with even relatively small amounts of the appropriate plastic material can provide the properties needed for a paperboard suitable for many demanding applications, such as liquid or food packaging board. In liquid or food packaging board, polyolefin coatings are often used as liquid barrier layers, heat seal layers, and adhesives.

[0004] The foaming tendency of beer often limits the use of paperboard-based disposable cups for serving beer. Filling the cups takes too long compared to glass or plastic beer cups due to excessive foaming. Especially at large festivals and similar events, cups must be filled very quickly. A typical requirement is that a cup must be able to hold 400 ml of beer in 20 seconds without overflowing. This requirement is not met by current 2PE (double polyethylene coated layer) paperboard-based cups. For example, because paperboard cups need to be filled slowly with beer, current automatic tapping machines are not suitable without modification, which affects the amount of beer that can be sold.

[0005] Previous attempts to solve the problem of excessive beer foam in paperboard-based disposable cups have been made, for example, by adding surfactants to the polymer coating that forms the interior surface of the cup, but adding additional ingredients to a surface that is intended to come into contact with the beverage to be consumed is generally undesirable.

[0006] Thus, there remains a need for an improved solution for replacing plastic disposable cups with paperboard-based disposable cups while avoiding the problem of excessive foam when serving beer.

[0007] Description of the Invention An object of the present disclosure is to provide a paperboard-based disposable cup that reduces foaming when serving beer.

[0008] It is a further object of the present disclosure to provide a paperboard-based disposable cup that reduces foaming when serving beer, using only ingredients traditionally used in paperboard-based disposable cups.

[0009] The above objectives, as well as other objectives which will be realized by those skilled in the art in light of this disclosure, are achieved by various aspects of the present disclosure.

[0010] According to a first aspect described herein, there is provided a paperboard-based disposable cup comprising: 1. A paperboard-based disposable cup formed from a paperboard-based laminate, comprising: A first surface of the paperboard-based laminate forming the interior surface of the paperboard-based disposable cup comprises: Basis weight: 10-20g / m 2 a pigment coating layer in the range of Basis weight: 5 to 25 g / m 2 an outermost polymer coating layer in the range of wherein the interior surface of the paperboard-based disposable cup has a PPS surface smoothness of <3 μm as determined in accordance with ISO 8791-4:2007.

[0011] Surprisingly, it has been found that the surface energy of the cardboard has little effect on foam formation. Instead, it has been found that the smoothness of the cup's inner surface is the primary factor affecting foam formation. The present invention is based on the realization that a very smooth surface can be achieved on the inner surface by providing a pigment coating layer underneath the outermost polymer coating layer that forms the inner surface of the cup. A smooth surface, with a PPS surface smoothness of <3 μm as determined in accordance with ISO 8791-4:2007, has been found to significantly reduce the tendency of beer served in the cup to foam.

[0012] Paperboard generally refers to a strong, thick paper or corrugated board containing cellulose fibers used for boxes and other types of packaging. Paperboard can be either bleached or unbleached, coated or uncoated, and can be produced in a variety of thicknesses depending on the end-use requirements.

[0013] The paperboard substrate used in the process of the present invention typically has a basis weight of at least 100 g / m 2 and the density is 600 to 1000 kg / m 3Unless otherwise specified, basis weight is determined according to the ISO 536 standard. Unless otherwise specified, density is determined according to the ISO 534 standard. In some embodiments, the paperboard-based laminate of the paperboard-based disposable cup has a weight of 150 to 400 g / m 2 In some embodiments, the paperboard substrate has a bulk of >1.1 m2, as determined according to ISO 534. 3 / kg, preferably >1.2m 3 / kg, more preferably >1.3m 3 / kg.

[0014] Paperboard can be a single-ply material or it can be a multi-ply material made up of two or more plies.

[0015] In some embodiments, the paperboard substrate is a multi-ply paperboard. In some embodiments, the paperboard substrate is a multi-ply paperboard made up of two or more plies. In some embodiments, the paperboard substrate is a multi-ply paperboard made up of three or more plies.

[0016] A common type of multi-ply board consists of a low density mid-ply (sometimes called a "bulk ply") sandwiched between two high density outer plies. The low density mid-ply is typically 750 kg / m² in density. 3 less than, preferably less than 700, less than 650, less than 600, less than 550, less than 500, less than 450, less than 400, or less than 350 kg / m 3 The denser outer ply is typically at least 100 kg / m2 denser than the middle ply. 3 Higher, preferably at least 200 kg / m higher density than the mid-ply 3 expensive.

[0017] The paperboard substrate typically contains kraft pulp. In some embodiments, the paperboard substrate is made of kraft pulp. In some embodiments, the paperboard substrate is made of a mixture of kraft pulp and chemi-thermomechanical pulp (CTMP) or other mechanical pulp. In embodiments including a low-density middle ply sandwiched between two high-density outer plies, the outer ply may preferably be made of kraft pulp, and the middle ply may preferably be made of a mixture of kraft pulp and chemi-thermomechanical pulp (CTMP) or other mechanical pulp.

[0018] Due to the fibrous composition of the paperboard substrate, the paperboard substrate may typically have a relatively rough surface. In some embodiments, the paperboard substrate has a surface smoothness PPS (Parker Print-Surf) of >3 μm, typically >5 μm, as determined according to ISO 8791-4:2007.

[0019] A paperboard-based laminate is a packaging material formed primarily from a paperboard substrate that, in addition to the paperboard substrate, includes additional layers or coatings designed to improve the performance and / or appearance of the laminate.

[0020] The paperboard substrate of a paperboard-based disposable cup has a pigment coating layer on a first surface facing the interior of the cup. The pigment coating is a coating containing at least one pigment and at least one binder. The pigment and binder are typically applied to the surface of the paperboard substrate in the form of a liquid dispersion, preferably an aqueous dispersion, and then dried to obtain the pigment coating layer.

[0021] The basis weight of the pigment coating layer is 10 to 20 g / m 2 In some embodiments, the pigment coating layer has a basis weight in the range of 13 to 15 g / m 2 is in the range.

[0022] In some embodiments, the pigment coating layer contains at least one pigment and at least one binder, ie, 60 to 70 wt % pigment and 20 to 30 wt % binder, based on dry weight.

[0023] In some embodiments, the pigment comprises calcium carbonate and a platy pigment, the platy pigment preferably being selected from the group consisting of kaolin, talc, or mixtures thereof.

[0024] The binder may comprise a single binder or a combination of binders. The binder may preferably comprise a water-dispersible or water-soluble binder, or a combination thereof. In some embodiments, the binder is a latex, preferably selected from the group consisting of a styrene acrylic (SA) latex, a styrene butadiene (SB) latex, or a mixture thereof.

[0025] The pigment coating layer may preferably be applied in at least two distinct coating steps with drying of the coated film between these steps, and thus in some embodiments the pigment coating layer consists of two or more sub-layers.

[0026] In some embodiments, the pigment coating layer comprises a precoat layer formed on a paperboard substrate and a topcoat layer formed on the precoat layer.

[0027] In some embodiments, the precoat layer has a basis weight of 5 to 15 g / m 2 range, preferably 6 to 12 g / m 2 is in the range.

[0028] In some embodiments, the precoat layer contains, on a dry weight basis, 75 to 95 weight percent pigment and 5 to 25 weight percent binder.

[0029] In some embodiments, the pigment in the precoat layer is calcium carbonate or a mixture of calcium carbonate and talc.

[0030] In some embodiments, the topcoat layer has a basis weight of 5 to 15 g / m 2 range, preferably 6 to 9 g / m 2 is in the range.

[0031] In some embodiments, the topcoat layer contains, on a dry weight basis, 20 to 50 wt % pigment and 50 to 80 wt % binder.

[0032] In some embodiments, the pigment in the topcoat layer is a platy pigment selected from the group consisting of kaolin, talc, or mixtures thereof.

[0033] In some embodiments, the platelet-shaped pigments in the topcoat layer have an aspect ratio of greater than 10, preferably greater than 20.

[0034] The pigment coating layer may also be calendered, preferably with a soft calender or belt calender.

[0035] In some embodiments, the pigment coating layer has a PPS surface smoothness of <2 μm, preferably <1.7 μm, and more preferably <1.5 μm, determined according to ISO 8791-4:2007.

[0036] The paperboard-based laminate further comprises an outermost polymer coating layer formed on the pigment coating layer. The outermost polymer coating layer preferably provides liquid barrier properties and mechanical protection to the paperboard-based laminate surface. The outermost polymer coating layer is also preferably heat-sealable.

[0037] The outermost polymer coating layer is preferably applied onto the pigment coating layer by extrusion coating, which is a process in which molten plastic material is applied to a substrate to form a very thin, smooth, and uniform layer. That is, in a preferred embodiment, the outermost polymer coating layer is an outermost extrusion coated polymer layer.

[0038] The outermost polymer coating layer may comprise any of the thermoplastic polymers commonly used in protective and / or heat-sealable layers in paperboard-based packaging laminates, or polymers used in liquid or food packaging boards in particular, such as polybutylene succinate (PBS), poly(butylene succinate-co-butylene adipate) (PBSA), polycaprolactone (PCL), poly(glycolic acid) (PGA), polyvinyl alcohol (PVOH), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polyhydroxyalkanoates (PHA), polyhydroxybutyrate (PHB), starch, thermoplastic starch (TPS), acetic acid, etc. Examples of suitable polymers include cellulose (CA), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene furanoate (PEF), polypropylene (PP), polyamide 6 (PA6), polyamide 66 (PA66), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 10.10 (PA10.10), and polyamide 6.10 (PA6.10). Preferred examples include polyethylene (PE), polyethylene terephthalate (PET), polyethylene furanoate (PEF), polypropylene (PP), polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polyglycolic acid (PGA), polyvinyl alcohol (PVOH), and starch. Polyethylene, particularly low-density polyethylene (LDPE) and high-density polyethylene (HDPE), is the most common and versatile polymer used in packaging cardboard for liquids and food. In some embodiments, the outermost polymer coating layer comprises polyethylene, preferably low density polyethylene (LDPE). The polymers used are preferably made from renewable materials.

[0039] Alternatively, the outermost polymer coating layer is applied onto the pigment coating layer by a liquid coating method. In some embodiments, the polymer is applied in the form of a dispersion, latex, or solution of the polymer in a liquid carrier, followed by drying to form the outermost polymer coating layer. An outermost polymer coating layer applied by a liquid coating method can be applied by a contact or non-contact coating method. Examples of useful coating methods include, but are not limited to, rod coating, curtain coating, film press coating, cast coating, transfer coating, size press coating, flexographic coating, gate roll coating, twin-roll HSM coating, blade coating (e.g., short dwell time blade coating), jet applicator coating, spray coating, gravure coating, or reverse gravure coating. In a preferred embodiment, the liquid dispersion is applied by blade coating.

[0040] The polymer, which is applied in the form of a dispersion, latex, or solution of the polymer in the liquid carrier, may be selected from the group consisting of, for example, latex (e.g., styrene acrylate (SA) latex, styrene butadiene (SB) latex, or mixtures thereof), starch, carboxymethyl cellulose (CMC), polyolefin (e.g., polyethylene (PE), polypropylene (PP), or copolymers of polyethylene and polypropylene), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), and polylactic acid (PLA).

[0041] In some embodiments, the outermost polymeric coating layer further comprises 1 to 20 weight percent pigment on a dry weight basis.

[0042] The basis weight of the outermost polymer coating layer is 5 to 25 g / m 2In some embodiments, the outermost polymeric coating layer has a basis weight in the range of 9 to 15 g / m 2 is in the range.

[0043] Due to the underlying pigment coating layer, the outermost polymer coating layer has a very smooth surface. More specifically, the outermost polymer coating layer forming the interior surface of the paperboard-based disposable cup has a PPS surface smoothness of <3 μm, as determined according to ISO 8791-4:2007.

[0044] In some embodiments, the interior surface of the paperboard-based disposable cup has a PPS surface smoothness of <2 μm, preferably <1.9 μm, more preferably <1.8 μm, as determined according to ISO 8791-4:2007.

[0045] The second side of the paperboard-based laminate, which forms the exterior surface of the paperboard-based disposable cup, may also be provided with one or more coating layers, such as a coating layer to improve the moisture resistance or printability of the exterior surface of the paperboard-based disposable cup.

[0046] In some embodiments, the second side of the paperboard-based laminate forming the exterior surface of the paperboard-based disposable cup has a thickness of 5 to 50 g / m 2 The pigment coating layer has a basis weight in the range of 1000 to 15000.

[0047] In some embodiments, the second side of the paperboard-based laminate forming the exterior surface of the paperboard-based disposable cup has a thickness of 5 to 50 g / m 2 The extrusion coating comprises an outermost polymer layer, preferably a polyethylene layer, having a basis weight in the range of 1000 sq. ft. to 1000 sq. m.

[0048] The paperboard-based disposable cup is intended for serving beverages in general, and beer in particular. In some embodiments, the paperboard-based disposable cup has an internal volume in the range of 50 to 2000 ml.

[0049] According to a second aspect described herein, there is provided a method of manufacturing: 1. A method for manufacturing a paperboard-based disposable cup, comprising: a) Producing a paperboard-based laminate by the following steps i. to iii.: i. providing a paperboard substrate; ii. A liquid dispersion containing a pigment and a binder is coated onto a first surface of the paperboard substrate, and the coated liquid dispersion is dried to obtain a paperboard substrate having a basis weight of 10 to 20 g / m 2 and having a PPS surface smoothness of <2 μm, preferably <1.7 μm, more preferably <1.5 μm, determined according to ISO 8791-4:2007. iii. A polymer layer is applied onto the pigment coating layer by extrusion or liquid coating to a basis weight of 5 to 25 g / m 2 and obtaining an outermost polymer coating layer having a PPS surface smoothness of <3 μm as determined in accordance with ISO 8791-4:2007; b) converting the paperboard-based laminate into a paperboard-based disposable cup, wherein the outermost polymer coating layer forms the interior surface of the paperboard-based disposable cup. A method comprising:

[0050] The paperboard substrate, pigment coating layer, and outermost polymeric coating layer may be further defined as described above with reference to the first embodiment.

[0051] In some embodiments, the pigment coating layer is formed by applying a first liquid dispersion containing a pigment and a binder onto a first surface of a paperboard substrate, drying the applied first liquid dispersion to obtain a precoat layer, applying a second liquid dispersion containing a pigment and a binder onto the precoat layer, and drying the applied second liquid dispersion to obtain a topcoat layer on the precoat layer. The compositions and basis weights of the precoat layer and the topcoat layer may be the same or different. The compositions and basis weights of the precoat layer and the topcoat layer may be further defined as described above with reference to the first aspect.

[0052] The liquid dispersion can be applied by contact or non-contact coating methods. Examples of useful coating methods include, but are not limited to, rod coating, curtain coating, film press coating, cast coating, transfer coating, size press coating, flexographic coating, gate roll coating, twin roll HSM coating, blade coating (e.g., short residence time blade coating), jet applicator coating, spray coating, gravure coating, or reverse gravure coating. In a preferred embodiment, the liquid dispersion is applied by blade coating.

[0053] The polymer applied in iii. is preferably applied by extrusion coating. The surface of the cooling cylinder used in extrusion coating is preferably smooth. In some embodiments, the cooling cylinder used in extrusion coating is chrome plated. In some embodiments, the cooling cylinder used in extrusion coating is highly polished. In some embodiments, the surface of the cooling cylinder used in extrusion coating has an average roughness (Ra) of <0.25 μm, preferably <0.10 μm, more preferably <0.025 μm. In some embodiments, the cooling cylinder used in extrusion coating is of the "GLF" type. In some embodiments, the cooling cylinder used in extrusion coating is of the mirror-finished or mirror-pocket type.

[0054] Generally, while products, polymers, materials, layers, and processes are described in terms of "comprises" various components or steps, these products, polymers, materials, layers, and processes can also consist essentially of or consist of the various components and steps.

[0055] While the present invention has been described with reference to various exemplary embodiments, it will be recognized by those skilled in the art that various modifications can be made and equivalents may be substituted for these elements without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but the invention will include all embodiments falling within the scope of the appended claims.

[0056] Example Beer pouring test The equipment used in the pouring test consisted of a laboratory stand and two clamps. A 330 ml beer can filled with lager beer was opened and attached horizontally to the upper clamp. A 75 mm glass funnel was attached to the lower clamp to simulate a beer spout. The final pour angle was adjusted so that the 330 ml beer can was emptied in 17 seconds. The time was monitored with a stopwatch. This time was chosen based on the assumption that a commercially available beer tap would fill a cup with 400 ml of beer in 20 seconds. The distance between the bottom of the beer can and the top of the glass funnel was approximately 30 mm during the setup. The beer temperature for this experiment was 4°C.

[0057] A 500 ml disposable plastic (PP) beer cup was used as a reference sample. The 500 ml disposable plastic beer cup was placed under the outlet of the glass funnel. The distance between this outlet and the inner wall of the cup was approximately 30-40 mm. The cup was positioned at a 20° angle to a flat table surface, assisted by a plastic support placed under the cup. The beer first contacted the wall of the cup, not the bottom as in a typical beer tap setup. The number of parallel determinations was three.

[0058] The same procedure was then repeated using different types of coated paperboard as the inner surface of the cup, as shown in Table 1. These paperboards included three different standard polymer-coated cardboards and two different cardboards according to the proposed inventive concept. The inner wall of the plastic cup was covered with a paperboard substrate before the pour test. The foam and liquid matrix heights were marked on the outer surface of the cup after immediately removing the paperboard cover inside the cup. The entire pour test was recorded with a video camera for quality assurance purposes to document the beer foam behavior.

[0059] Properties and phenomena tracked during testing include: i) Height of the foam layer formed ii) foam structure (lamellar or not), and iii) Possibility of excessive foaming. The presence of lamellar foam is theoretically desirable because it exhibits rapid foam breakdown and therefore less risk of excessive foaming. Additionally, the PPS (Parker Print-Surf) surface smoothness of each inner surface was determined according to ISO 8791-4:2007 (1.0 MPa).

[0060] TIFF2025526846000001.tif247170TIFF2025526846000002.tif11170Note: Foaming >10 cm means that the excessive foaming was so intense that the initial height of the foam layer was indeterminable. 10 cm still had some measurable height, and the excessive foaming was not severe.

Claims

1. A disposable cup made of cardboard, the disposable cup made of cardboard is formed from a laminate made of cardboard. The first surface of the cardboard-based laminate that forms the inner surface of the cardboard-based disposable cup is Basis weight: 10-20 g / m² ２ A pigment coating layer within the range, and Basis weight: 5-25 g / m² ２ The outermost polymer coating layer within this range, The inner surface of the cardboard-based disposable cup is determined according to ISO 8791-4:2007, and the PPS surface smoothness is <3 μm. Cardboard-based disposable cups.

2. A disposable disposable cup made of cardboard, according to claim 1, wherein the cardboard substrate is determined in accordance with ISO 8791-4:2007 and has a PPS surface smoothness of >3 μm.

3. The pigment coating layer has a basis weight of 13-15 g / m². ２ A disposable cardboard cup according to claim 1, within the range of a cardboard base.

4. A disposable cardboard cup according to claim 1, wherein the pigment coating layer contains at least one pigment and at least one binder.

5. A disposable cardboard cup according to claim 1, wherein the pigment coating layer contains 60 to 70% by weight of pigment and 20 to 30% by weight of binder, based on dry weight.

6. A disposable cardboard cup according to claim 4, wherein the pigment contains calcium carbonate and a plate-like pigment, preferably selected from the group consisting of kaolin, talc, or a mixture thereof.

7. A disposable cardboard cup according to claim 4, wherein the binder is a latex, preferably selected from the group consisting of styrene-acrylic (SA) latex, styrene-butadiene (SB) latex, or a mixture thereof.

8. A disposable cardboard cup according to claim 1, wherein the pigment coating layer consists of two or more sub-layers.

9. A disposable cup made of cardboard according to claim 8, wherein the pigment coating layer comprises a pre-coat layer formed on a cardboard substrate and a topcoat layer formed on the pre-coat layer.

10. The pre-coat layer has a basis weight of 5 to 15 g / m². ２ In the range of 6 to 12 g / m², preferably 6 to 12 g / m². ２ A disposable cardboard cup according to claim 9, within the range of a cardboard base.

11. A disposable cardboard cup according to claim 9, wherein the pre-coat layer contains 75 to 95% by weight of pigment and 5 to 25% by weight of binder, based on dry weight.

12. A disposable cardboard cup according to claim 9, wherein the pigment in the pre-coat layer is calcium carbonate or a mixture of calcium carbonate and talc.

13. The topcoat layer has a basis weight of 5 to 15 g / m². ２ In the range of 6 to 9 g / m², preferably 6 to 9 g / m². ２ A disposable cardboard cup according to claim 9, within the range of a cardboard base.

14. A disposable cardboard cup according to claim 9, wherein the top coat layer contains 20 to 50% by weight of pigment and 50 to 80% by weight of binder, based on dry weight.

15. A disposable cardboard cup according to claim 9, wherein the pigment in the top coat layer is a plate-shaped pigment selected from the group consisting of kaolin, talc, or mixtures thereof.

16. A disposable cardboard-based cup according to claim 15, wherein the plate-like pigment in the top coat layer has an aspect ratio of more than 10, preferably more than 20.

17. A disposable cardboard-based cup according to claim 1, wherein the pigment coating layer has a PPS surface smoothness of <2 μm, preferably <1.7 μm, and more preferably <1.5 μm, as determined in accordance with ISO 8791-4:2007.

18. A disposable cardboard cup according to claim 1, wherein the inner surface of the cardboard-based disposable cup has a PPS surface smoothness of <2 μm, preferably <1.9 μm, and more preferably <1.8 μm, as determined in accordance with ISO 8791-4:2007.

19. A method for manufacturing disposable cups based on cardboard, a) Manufacture a paperboard-based laminate according to the following i. to iii.: i. Prepare a cardboard substrate. ii. A liquid dispersion containing a pigment and a binder is applied to the first surface of a paperboard substrate, and the applied liquid dispersion is dried to obtain a basis weight of 10 to 20 g / m². ２ To obtain a pigment coating layer in the range of <2 μm, preferably <1.7 μm, more preferably <1.5 μm, determined according to ISO 8791-4:2007, the PPS surface smoothness is <2 μm, preferably <1.7 μm, more preferably <1.5 μm. iii. Applying a polymer coating layer on the pigment coating layer to obtain the outermost polymer coating layer having a basis weight in the range of 5 to 25 g / m ２ and the outermost polymer coating layer having a PPS surface smoothness of < 3 µm as determined in accordance with ISO 8791-4:2007, and b) Converting a cardboard-based laminate into a cardboard-based disposable cup, wherein the outermost polymer coating layer forms the inner surface of the cardboard-based disposable cup. Methods that include...