Paper cup without plastic coating and method of manufacturing the same

Abstract

Paper cup (1) without plastic coating comprising of cup wall (2) forming hollow truncated conical shape (7), bottom (6) sealing hollow truncated conical shape (7) at its smaller diameter end (4), curl profile (5) formed at larger diameter end (3) of cup wall (2) and knurl profile (22) formed at smaller diameter end (4) of cup wall (2) and method of its manufacturing is disclosed. Cup wall (2) and bottom (6) is made up of paperboard composed from 94-96% of cellulose pulp, 1-2% of starch and 2-3% of rosin without any synthetic coatings or polymers. Welding adhesive used is polyolefin particles of 5-8 µm size uniformly disperse in water. By minimizing use of plastics and focusing on sustainable materials, present paper cup (1) and manufacturing process ensures compliance with regulatory requirements and supports production of high-quality, eco-friendly paper cups.

Description

[0001] TITLE

[0002] Paper cup without plastic coating and method of manufacturing the same

[0003] FIELD OF THE INVENTION

[0004] Present invention relates to a paper cup and method for manufacturing the paper cup. Present invention more particularly relates to a plastic fee paper cup and a method for manufacturing the same wherein the paper cup is made up of a paperboard composed paper pulp with starch based sizing agent without any synthetic coatings or polymers. Particulate aqueous solution of polymer is used as a welding adhesive.

[0005] Paper cup as per present invention is made up of food grade material, biodegradable, recyclable, economic, easy to manufacture, printable, with least stackable volume and capable of holding hot and cold beverages for its designed time without distortion of its shape.

[0006] BACKGROUND OF THE INVENTION

[0007] The paper cup, developed in the early 20th century as a life-saving technology, continues to serve vital health and safety roles today. Originating during the temperance movement in the U.S., it replaced communal drinking cups, which posed public health risks. Lawrence Luellen created the first disposable paper cup in 1907, influenced by public health campaigns against the spread of diseases like tuberculosis. The paper cup gained popularity during the 1918 Spanish flu pandemic and has since evolved, with innovations like the Solo Cup and eco- friendly, renewable options. Today, paper cups are widely used in various settings, driven by convenience and sustainability trends.

[0008] Reported life cycle analysis (LCA) revealed that paper cups often have the lowest carbon footprint, which can be reduced by 54% through recycling. Conducted by VTT Technical Research Centre of Finland Ltd. in 2018-2019, the study highlighted that a paper cup accounts for just 4% of the climate impact of a takeaway latte, with the rest attributed to coffee and milk production. Ceramic cups must be used at least 350 times to match the lower carbon footprint of a paper cup. Recycling and using plant-based materials in paper cups can further minimize their environmental impact.

[0009] Single-use beverage cups, commonly made from polystyrene or polymer-lined paperboard, are among the most littered items on beaches globally, contributing to marine pollution and negatively impacting marine biodiversity, tourism, fishing, and shipping industries. Despite their convenience, especially in middle- to low- income countries, the 500 billion disposable cups used annually are often poorly recycled, leading to significant environmental damage. As the demand for disposable cups grows, urgent action at policy, business, and individual levels is needed to promote sustainable alternatives, such as reusable cups and better waste management, though these also present challenges.

[0010] Single-use cups have similar environmental impacts regardless of the material they are made of (whether bio-plastic, fossil-based plastic or paper). When choosing between single-use options, the least environmentally problematic choice may be to use paper cups, especially if the currently low recycling rates can be turned around.

[0011] Innovations in paper cups focus on enhancing sustainability, reducing environmental impact, and improving functionality.

[0012] Some innovations involve designing paper cups that are more durable. Innovations in paper fiber technology have led to the development of stronger, lighter paper cups, reducing the amount of material needed while maintaining durability and functionality. Patent application no. 270 / KOL / 2011 discloses paper cup with reinforcement applied in the form of coating to the tubular wall and coated with plastic material on interior surface that comes in contact with liquid to ensure that the shape of the peripheral deforming entity is not altered even under load or deformed only up to the extent that the peripheral deforming entity can still perform intended task.

[0013] Patent application no. CN213677943 discloses an environment-friendly paper cup that does not have of moulding, through placing first folded sheet and second folded sheet with the cup both sides, knot first button and second button, first button and second button are together buckled, just can be fixed in the cup outside with first folded sheet and second folded sheet, and the gauze through holding first folded sheet and second folded sheet outside can convenient to use, the utility model discloses hand and the outside direct contact of cup when drinking have been avoided, and when need not using, still conveniently dismantle first folded sheet and second folded sheet and get off not occupation space. The first folding plate and the second folding plate are made of environment-friendly materials and can be repeatedly used.

[0014] Patent application no. CN216581933 provides a disposable paper cup with a simple cup cover, comprising a cup body, the cup mouth of the cup body is provided with a rolled brim, an outer side surface of the cup body is attached with a tin foil cover plate adapted to the cup mouth of the cup body, the tin foil cover plate is connected to the rolled brim through a connecting piece, and a plurality of fixed arms are evenly distributed on the periphery of the tin foil cover plate; the inner side surface of the cup body is provided with a polybutylene succinate coating layer.

[0015] To overcome the problem associated with tight connection and sealing between the paper cup and the cup cover, Patent application no. CN218907944U discloses disposable cup made of laminated paper wherein the inner wall of the cup is a laminated layer, the cup cover is provided with an outer layer and an inner layer, the inner layer is made of a material that can be welded with the laminated layer, the laminated layer of the cup mouth is connected to the contact part of the inner layer of the cup cover. By local heating or using ultrasonic high-frequency vibration to generate local heat, the coating layer at the mouth of the cup and the inner layer of the cup lid can be welded without additional glue.

[0016] Patent application no. CN220563125U discloses a disposable anti-deformation plastic cup comprises a cup body, wherein the cup body is gradually expanded from the cup bottom to the cup mouth, the edge of the cup mouth is bent toward the cup bottom to form a first bending portion, a support ring is embedded in the first bending portion, and the support ring is sleeved outside the cup body.

[0017] Patent application no. JP2001233319A discloses a paper cup-shaped container made of a paper base material and a composite sheet having a heat-sealable resin layer on the inner surface, and is composed of a body and a bottom, and has a flat rim with the rim of the opening curled outward. The rim and a lid material placed on the opening to cover it are hermetically sealed around the rim. The paper cupshaped container is characterized in that an opening hole is drilled in the bottom, and a pull tab tape is heat-sealed from the outside of the paper cup to cover the opening, leaving a partial unsealed portion at the opening start part which becomes the handle.

[0018] Efforts to create easily recyclable paper cups include cups made with a thinner plastic lining or cups designed for improved separation of materials during recycling. Patent application no. JPH0662944A discloses a paper cup made of paper with plastic laminated on at least one or both sides of the paper, wherein the plastic laminated on the paper is a biodegradable plastic whose main component is a biodegradable microbially produced polyester or an aliphatic polyester, and the method for sealing the sides of the paper cup is to heat and melt one or both of the plastics in the sealing portion with hot air at 250°C or less, and then directly press the plastic and paper or the plastic and paper on the sealing surface together. Patent application no. CN221189497U discloses the utility model aims to provide a sealed cup combined with paper and plastic, so as to achieve good matching performance between the plastic cup mouth and the plastic cover, and to continue the good performance of the paper cup such as being printable and externally stickable.

[0019] Some companies have developed plastic-free paper cups that use a water-based dispersion barrier, making them fully recyclable in standard paper recycling streams without the need to separate plastic from paper. Patent application no. US20220169430A1 discloses a vessel comprising a wall at least partially made of a compostable or biodegradable material, having an interior surface enclosing a lumen and an exterior surface; and a PECVD coating set on the interior surface, the exterior surface, or both. The PECVD coating set comprises a barrier coating or layer of SiOx, in which x is from about 1.5 to about 2.9 as measured by XPS. The PECVD coating set optionally further comprises a tie coating or layer comprising SiOxCy, in which x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3 as measured by X-ray photoelectron spectroscopy (XPS); a pH protective coating or layer comprising SiOxCy, in which x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3 as measured by XPS; or both. The vessel may also include a lacquer coating between the surface of the wall and the PECVD coating set. In some embodiments, the vessel may be a single use coffee or tea pod. As per disclosure in a patent application no. JP2003020025A a material quality constitution of a barrel member and a bottom member is composed of a composite material (20) in which a paper layer (11), a natural gum layer (12) containing natural rubber or its derivative, natural resin showing paper permeability, wax or the like and their derivatives, and ester compound layer (13) of lauric acid and dextrin are laminated in this order. It is also preferable to arranged a second paper layer (14) between the natural gum layer of composite material and an ester compound layer showing a sealing rate of lauric acid and a hydroxyl group of dextrin more than 80%.

[0020] Advances in insulation technology have enabled the creation of paper cups with enhanced thermal properties, allowing them to keep beverages hot or cold for longer periods without the need for additional sleeves or double -cupping. Paper cup manufacturers are increasingly sourcing paper from sustainably managed forests and using renewable materials to reduce the environmental footprint of paper cup production. Innovations include using environmentally friendly inks and dyes for branding and designs on paper cups, which are easier to break down during recycling and are less harmful to the environment. These innovations aim to make paper cups more sustainable and environmentally friendly while maintaining their convenience and usability.

[0021] The plastic coating on paper cups makes them difficult to recycle. The paper and plastic layers need to be separated, which many recycling facilities cannot do efficiently. Improper recycling of cups contribute to environmental pollution, as they often end up in landfills or as litter, where they can take years to decompose. The production of plastic-coated paper cups requires significant fossil fuels for plastic adding to the carbon footprint. These cups are designed for single use, leading to high consumption and waste. Unlike ceramic or metal cups, they cannot be reused multiple times, exacerbating waste management issues if it is having plastic content. Improper discarding of plastic coated paper cup can lead to breakdown of the plastic coating into microplastics, which can enter waterways and harm marine life. There are concerns that the plastic coating or any other biodegradable material coating could leach chemicals into hot beverages, potentially posing health risks over time. If the paper cups are made out of paper without any plastic or reinforce coating, material of cup becomes soggy by catching the liquid and not able to hold liquids for longer time.

[0022] Government of different countries is working with an aim to become a forerunner in the global fight against marine litter and plastic pollution with an aims to reduce the volume and impact of certain plastic products on the environment. As a part of the same certain plastic containing products are band or additional duties or taxes are imposed impacting business at large and additional cost burden on end users.

[0023] OBJECTS OF THE INVENTION Present invention provides a paper cup and method for manufacturing the same that overcomes problems of the prior art as discussed in the previous section.

[0024] Principal object of present invention is to provide a plastic fee paper cup and a method for manufacturing the same.

[0025] Another object of the present invention is to provide a paper cup that is manufactured using a paperboard composed of paper pulp with starch based sizing agent without any synthetic coatings or polymers.

[0026] Another object of present invention is to provide a paper cup wherein particulate aqueous solution of polymer is used as a welding adhesive without its exposer to inner surfaces of the paper cup preventing its dilution in to hot or cold liquid handled by it.

[0027] Another object of the present invention is to provide a paper cup that can hold hot and cold beverages for its designed time without its distortion and becoming soggy by absorbing liquid.

[0028] Another object of the present invention is to provide a paper cup that is biodegradable, recyclable, economic, easy to manufacture and capable of holding hot and cold beverages for its designed time without distortion of its shape.

[0029] SUMMARY OF THE INVENTION

[0030] The paper cup without plastic coating comprising of a cup wall forming a hollow truncated conical shape, a bottom sealing the hollow truncated conical shape at its smaller diameter end, a curl profde formed at a larger diameter end of the cup wall and a knurl profile formed at the smaller diameter end of the cup wall is disclosed. Cup wall and the bottom is made up of a paperboard composed from 94-96% of cellulose pulp, 1-2% of starch and 2-3% of rosin without any synthetic coatings or polymers. Welding adhesive used is polyolefin particles of 5-8 pm size uniformly disperse in water. A method of manufacturing the paper cup without plastic coating as per present invention includes; cutting a segmental disc shape blank of a paperboard with dimensions corresponding to a development drawings of a cup wall; forming the frustoconical cup wall by feeding the cup wall blanks into a cup forming machines to overlap leap areas of the segmental disc shape blank followed by application of a welding adhesive in between the overlapping leap areas and curing the welding adhesive at a temperature of 180-210 °C and a pressure that is adequate for sealing of the overlap leap areas along a seam preventing spilling of the welding adhesive out of the overlapped leap areas; forming a curl profde at a larger diameter end and a knurl profile at the smaller diameter end of the cup wall; cutting a blank of bottom of a paperboard with dimensions according to a development drawings of a bottom; forming a sealing ring of the bottom by bending a partial radial portion starting from the periphery of the blank of the bottom; assembling the bottom with the cup wall by inserting the sealing ring of the bottom into the knurl profile of the cup wall to form a hollow truncated volume for accommodating hot or cold liquid and; applying a welding adhesive in between the contact surface of the knurl profile and the sealing ring and curing the welding adhesive at a temperature of 260-270 °C and a pressure that is adequate for sealing of the sealing ring with the knurl profile preventing spilling of the welding adhesive out of an overlapped area of the sealing ring and the knurl profile.

[0031] By minimizing the use of plastics and focusing on sustainable materials, present paper cup and manufacturing process ensures compliance with regulatory requirements and supports the production of high-quality, eco-friendly paper cups.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033] An illustrative embodiment of the invention is diagrammatically shown on the drawing.

[0034] FIG. 1 shows front view of a paper cup along with a partial cross sectional view. FIG. 2 shows an isometric view of a paper cup.

[0035] FIG. 3 shows enlarged view of detail A shown in FIG. 1. FIG. 4 shows enlarged view of detail B shown in FIG. 1.

[0036] FIG. 5 shows a segmental disc shaped blank of a cup wall.

[0037] FIG. 6 shows a blank of a bottom along with a bending line for forming a sealing ring.

[0038] FIG. 7 shows a stacking height of the cups.

[0039] FIG. 8 shows dimensional drawing of a paper cup as per example.

[0040] FIG. 9 shows an enlarged view of detail A shown in FIG. 8.

[0041] FIG. 10 shows an enlarged view of detail B as shown in FIG. 8.

[0042] FIG. 11 shows stacking height of fifty pieces of the paper cup as per present invention.

[0043] FIG. 12 shows FTIR spectra of the paper cup manufactured as per above example.

[0044] FIG. 13 shows the library correlation search results for the paper cup manufactured as per above example.

[0045] FIG. 14 shows sample FTIR spectra overlaid with the outer cardboard surface of the paper cup.

[0046] FIG. 15 shows the paper cup DCS curves for 2ndheat.

[0047] List of designations / reference numbers in figure

[0048] 1. a paper cup

[0049] 2. a cup wall

[0050] 3. a larger diameter end

[0051] 4. a smaller diameter end

[0052] 5. a curl profile

[0053] 6. a bottom

[0054] 7. a hollow truncated conical shape

[0055] 8. a seam

[0056] 9. a segmental disc shape blank

[0057] 10. a curl area

[0058] 11. a knurl area

[0059] 12. a leap area

[0060] 13. a leap area 14. a printing area

[0061] 15. a dimension of a segmental disc shape blank (9) corresponding to a larger diameter end (3)

[0062] 16. a dimension of a segmental disc shape blank (9) corresponding to a smaller diameter end (4)

[0063] 17. a dimension of a segmental disc shape blank (9) corresponding to a cup height measured along a cup wall (2)

[0064] 18. a blank of bottom

[0065] 19. a sealing ring of the bottom (6)

[0066] 20. a stacking height paper cups ( 1)

[0067] 21. a hollow truncated volume for accommodating hot or cold liquid,

[0068] 22. a knurl profile

[0069] 23. an inner surface of the cup wall (2)

[0070] 24. an inner surface of the bottom (6)

[0071] 25. a partial radial portion of a blank ( 18) of the bottom (6)

[0072] 26. an internal surface of a segmental disc shape blank (9)

[0073] 27. an external surface of a segmental disc shape blank (9)

[0074] DETAILED DESCRIPTION OF THE INVENTION

[0075] This invention relates to a paper cup that is plastic free and a method for manufacturing the said paper cup.

[0076] The description that follows is presented to enable person skilled in art to perform the present invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be apparent to those skilled in art, and the general principles discussed below may be applied to other embodiments and applications without departing from the scope and spirit of the invention. Therefore, the invention is not intended to be limited to the embodiments disclosed, but the invention is to be given the largest possible scope which is consistent with the principles and features described herein. FIG. 1 shows front view of a paper cup (1) along with a partial cross sectional view. FIG. 2 shows an isometric view of the paper cup (1). As shown in FIG. 1- 2, the paper cup (1) without plastic coating is comprising of a cup wall (2) forming a hollow truncated conical shape (7), a bottom (6) sealing the hollow truncated conical shape (7) at its smaller diameter end (4), a curl profde (5) formed at a larger diameter end (3) of the cup wall (2) and a knurl profile (22) formed at the smaller diameter end (4) of the cup wall (2).

[0077] FIG. 5 shows a segmental disc shaped blank (9) of the cup wall (2). In FIG. 5, a curl area (10) for forming of the curl profile (5), a knurl area (11) used for forming of the knurl profile (22), a leap area (12) provided on an external surface (27) of the segmental disc shaped blank (9), a leap area (13) provided an internal surface (26) of the segmental disc shaped blank (9) and a printing area (14) provided on the external surface area (27) are shown on the segmental disc shaped blank (9) of the cup wall (2). A dimension (15), a dimension (16) and a dimension (17) of a segmental disc shape blank (9) shown in FIG. 5 corresponds to the larger diameter end (3), the smaller diameter end (4) and a cup height measured along a cup wall (2) of a hollow truncated conical shape (7) of the paper cup (1).

[0078] For forming the hollow truncated conical shape (7) of the paper cup (1), the leap areas (12, 13) of a segmental disc shape blank (9) of the cup wall (2) as shown in FIG. 5 are overlapped and sealed along a seam (8) as shown in FIG. 1, by applying and curing a welding adhesive in between the overlapping leap areas (12, 13). Care is taken to ensure that the welding adhesive do not spread over an inner surface (23) of the cup wall (2) of the formed hollow truncated conical shape (7).

[0079] The curl profde (5) as show in FIG. 3 is formed at the larger diameter end (3) of the cup wall (2) by bending the curl area (10) of the segmental disc shape blank (9) as shown in FIG. 5. This curl profde (5) provides additional rigidity and a smooth finish for drinking. The knurl profde (22) is formed at the smaller diameter end (4) of the cup wall (2) as shown in FIG. 4 by bending the knurl area FIG. 6 shows a developed blank (18) of the bottom (6) along with a bending line for forming a sealing ring (19) by bending a partial radial portion (25) of the developed blank (18) of the bottom (6). The sealing ring (19) of the bottom (6) is formed by bending a partial radial portion (25) starting from the periphery of the bottom (6). The bottom (7) is assembled with the hollow truncated conical shape (7) by inserting the sealing ring (19) of the bottom (7) into the knurl profde (22) of the cup wall (2) as shown in FIG. 4. The bottom (7) is sealed with an inner surface (23) of the cup wall (2) by applying and curing the welding adhesives in between the sealing ring (19) and the knurl profile (22).

[0080] The knurl profile (22) at the smaller end (4) will impart rigidity to the formed hollow truncated conical shape (7) and provide geometrical configuration for assembling of the bottom (7) by inserting the sealing ring (19) of the bottom (7) and sealing of it for creating leak proof joint along with imparting stiffness to the paper cup (1) for holding the liquid without its distortion.

[0081] Care is taken to prevent application or exposer of the welding adhesive to the inner surface (23) of the cup wall (2) and an inner surface (24) of the bottom (6). The cup wall (2) sealed by the bottom (6) at its smaller diameter end (4) forms a hollow truncated volume (21) as shown in FIG. 1, for accommodating hot or cold liquid.

[0082] Material used for the cup wall (2) and the bottom (6) is a paperboard made up of paper pulp with a starch-based sizing agent. More specifically, the paperboard is made up of 94-96% of cellulose pulp, 1-2% of starch and 2-3% of rosin. The paperboard used is without any synthetic coatings or polymers. A sizing agent is a substance used in the production of paper to alter the surface properties of fibers, typically to reduce their absorbency and improve their strength, printability, and durability. Addition of starch in cellulose pulp for making the paperboard increase the internal bonding of cellulose fibers, resulting in improved tensile strength, burst strength, and folding endurance making the paperboard stronger and more durable. Addition of starch to cellulose enhances the surface strength, making the paper more resistant to picking, tearing, and dusting during printing or other processing stages. Addition of starch to cellulose reduces the paperboard’s absorbency, fdl in the gaps between fibers, creating a smoother surface ensuring that inks do not spread excessively and leads to improvement in paperboard printability which is particularly important for high-quality printing on the paper cup. Addition of starch to cellulose pulp makes the paperboard more hydrophobic thereby reducing the penetration of liquids, such as water or ink, into the paper, which is crucial for its application for making paper cup. Addition of starch in cellulose pulp used for making the paperboard increases stiffness and rigidity and, provide a degree of barrier protection against moisture and grease, which is beneficial in use of such paperboard as a material for manufacturing the paper cup. Starch is a relatively low -cost and abundant natural material, making it an economical choice for improving paperboard quality. Being a natural polymer, starch is biodegradable, making it an environmentally friendly option compared to synthetic sizing agents.

[0083] Rosin used along with starch in cellulose pulp to enhance the sizing process and improve the quality of the final paperboard. Rosin is primarily used to improve the water resistance of paper. When added to the pulp, rosin forms a hydrophobic coating around the cellulose fibers, which reduces the paper's ability to absorb water or other liquids which is important for use of the paperboards for making paper cup. While starch improves the surface strength and smoothness of the paperboard, rosin enhances the overall sizing effect by providing additional water resistance. The combination of starch and rosin ensures that the paperboard has both the necessary strength and the required resistance to moisture. Rosin act as an internal sizing agent when added directly to the cellulose pulp. This allows the fibers to be treated before the paperboard is formed, ensuring that the water resistance is distributed throughout the paper, not just on the surface. Rosin help to stabilize the paper’s structure and prevent it from becoming too alkaline, which could otherwise lead to degradation over time. Rosin is a relatively inexpensive, making it a cost-effective option for improving the paperboard quality. Its use along with starch allows achieving the desired paperboard properties without relying solely on more expensive synthetic sizing agents.

[0084] The welding adhesive used is polyolefin particles of 5-8 pm size uniformly disperse in water. Using an aqueous solution as a medium for polyolefin microparticles reduces the need for organic solvents, making the process more environmentally friendly and safer to handle. Polyolefins are chemically inert and resistant to many chemicals, oils, and moisture. This makes the adhesive suitable for paper cup application where the bond needs to withstand exposure to wet conditions, harsh chemicals and high temperature. Aqueous solution of polyolefin microparticles is used as a welding adhesive due to its ability to form strong, flexible, and durable bonds, its resistance to chemicals and moisture, and the advantages offered by the microparticle form in terms of application and performance.

[0085] A method of manufacturing the paper cup (1) without plastic coating is discussed.

[0086] First of all the cup wall blank (9) of the paperboard with dimensions corresponding to a development drawings of a cup wall (2) is cut. Then the frustoconical cup wall (2) is formed by feeding the cup wall blanks (9) into a cup forming machines to overlap leap areas (12, 13) of the cup wall blank (9). Welding adhesive is applied in between the overlapping leap areas (12, 13) and cured at a temperature of 180-210 °C and at a pressure that is adequate for sealing of the overlap leap areas (12, 13) along a seam (8) preventing spilling of the welding adhesive out of the overlapped leap areas (12, 13). The curl profile (5) is formed at the larger diameter end (3) and the knurl profile (22) is formed at the smaller diameter end (4) of the cup wall (2) using the cup forming machine. A blank of bottom (18) is cut out of a paperboard with dimensions according to a development drawing of the bottom (6). A sealing ring (19) of the bottom (6) is formed by bending a partial radial portion (25) starting from the periphery of the blank (18) of the bottom (6). The bottom (6) is assembled with the cup wall (2) by inserting the sealing ring (19) of the bottom (6) into the knurl profile (22) of the cup wall (2) to form a hollow truncated volume (21) for accommodating hot or cold liquid. The welding adhesive is applied in between the contact surface of the knurl profde (22) and the sealing ring (19) and cured at a temperature of 260-270 °C and at a pressure that is adequate for sealing of the sealing ring (19) with the knurl profde (22) preventing spilling of the welding adhesive out of an overlapped area of the sealing ring (19) and the knurl profde (22).

[0087] In the said method, the paperboard composed of 94-96% of cellulose pulp, 1-2% of starch and 2-3% of rosin without any synthetic coatings or polymers is used for the cup wall (2) and the bottom (6). In the said method, polyolefin particles of 5-8 pm size uniformly disperse in water is used as the welding adhesive.

[0088] FIG. 7 defines stacking height (20) of the paper cups.

[0089] BEST METHOF OF PERFORMING THE INVENTION

[0090] Present invention is implemented as per the example shown in FIG. 8 to manufacture the paper cup. Dimension of the paper cup are shown in FIG. 8. FIG. 9 shows an enlarged view of detail A shown in FIG. 8. FIG. 10 shows an enlarged view of detail B as shown in FIG. 8. FIG. 11 shows stacking height of fifty pieces of the paper cup (1) as per present invention. For the paper cup as per FIG. 8, a bottom dimension of the cup is 44.7 mm and an angle of the paper cup is 6.9 degree.

[0091] Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) test are performed to check presence of plastic if any on the inside of the paper cup (1) as per present invention.

[0092] FTIR was performed using a Nicolet iS20 FTIR spectrometer using following parameters:

[0093] Gain - 8

[0094] Optical velocity - 0.4747

[0095] Aperture - medium resolution Number of scans - 32

[0096] Resolution - 4cm'1

[0097] A sample cut from the paper cup (1) weighing approximately 5 mg was placed in non-hermetically sealed aluminium pan to allow release of gases. The test programme consisted of the following steps:

[0098] • First heat: 20 to 350°C at 10°C / min

[0099] • Hold: 350°C for 3 min

[0100] • Cooling cycle: 350 to 20°C at 10°C / min

[0101] • Hold: 20°C for 3 min

[0102] • Second heat: 20 to 350°C at 10°C / min

[0103] • Atmosphere: N2 at 50 ml / min

[0104] Two DSC runs were performed.

[0105] FIG. 12 shows FTIR spectra of the paper cup manufactured as per above example. FIG. 13 shows the library correlation search results for the paper cup manufactured as per above example. FIG. 14 shows sample FTIR spectra overlaid with the outer cardboard surface of the paper cup. FIG. 15 shows the paper cup DCS curves for 2ndheat.

[0106] The library correlation search gives the highest match to cellophane with the low match factor of (63.05). A low match with cellophane suggests the sample could have a similar chemical structure like cellulose. Moreover, the spectrum closely matches the outer cardboard surface of the paper cup. The DCS curve for the 2ndheat as per FIG. 15 shows a gently rising cure with no melting peak that would be expected from a plastic sample.

[0107] Based on the FTIR and DSC results the paper cup manufactured as per example is plastic free.

[0108] The Single-Use Plastics Directive (SUPD) is a legislative measure adopted by the European Union (EU) to reduce the impact of certain plastic products on the environment, particularly in marine settings. The paper cup as per present invention does not fall under the SUPD category because it consists of cellulose pulp with starch and rosin as sizing agents and, with welding adhesives used only for structural purposes and not considered part of the product. The REACH Regulation is a comprehensive framework implemented by the European Union (EU) to manage and control the risks associated with chemical substances. REACH stands for Registration, Evaluation, Authorisation, and Restriction of Chemicals. The welding adhesive used in the manufacturing process is polyolefin particles of 5-8 pm size uniformly disperse in water which is a polymer. However, since the welding adhesive is not a structural component of the product, the paper cup itself remains compliant with regulations prohibiting certain types of plastics.

[0109] The paper cup can perform its intended function without the welding adhesive component, as the welding adhesive is used primarily to hold the shape and integrity of the package. This aspect further supports the paper cup compliance with environmental directives.

[0110] By minimizing the use of plastics and focusing on sustainable materials, the present manufacturing process ensures compliance with regulatory requirements and supports the production of high-quality, eco-friendly paper cups.

Claims

CLAIMSWe claim:

1. A paper cup (1) without plastic coating comprising: a cup wall (2) forming a hollow truncated conical shape (7); a bottom (6) sealing the hollow truncated conical shape (7) at its smaller diameter end (4); a curl profde (5) formed at a larger diameter end (3) of the cup wall (2) and; a knurl profile (22) formed at the smaller diameter end (4) of the cup wall (2); characterized in that leap areas (12, 13) of a segmental disc shape blank (9) of the cup wall (2) is overlapped and sealed at a seam (8) by applying and curing a welding adhesive in between the overlapping leap areas (12, 13) without its exposer to an inner surface (23) of the cup wall (2) for forming the hollow truncated conical shape (7), a sealing ring (19) of the bottom (6) formed by bending a partial radial portion starting from the periphery of the bottom (6) is inserted into the knurl profde (22) of the cup wall (2) and sealed by applying and curing the welding adhesives in between the sealing ring (19) and the knurl profde (22) without exposer of the welding adhesive to the inner surface (23) of the cup wall (2) and an inner surface (24) of the bottom (6) to form a hollow truncated volume (21) for accommodating hot or cold liquid,the cup wall (2) and the bottom (6) is made up of a paperboard composed from 94-96% of cellulose pulp, 1-2% of starch and 2- 3% of rosin without any synthetic coatings or polymers and, the welding adhesive used is polyolefin particles of 5-8 pm size uniformly disperse in water.

2. A method of manufacturing the paper cup (1) without plastic coating comprising steps of: cutting a segmental disc shape blank (9)of a paperboard with dimensions corresponding to a development drawings of a cup wall (2); forming the frustoconical cup wall (2) by feeding the cup wall blanks (9) into a cup forming machines to overlap leap areas (12, 13) of the segmental disc shape blank (9) followed by application of a welding adhesive in between the overlapping leap areas (12, 13) and curing the welding adhesive at a temperature of 180-210 °C and a pressure that is adequate for sealing of the overlap leap areas (12, 13) along a seam (8) preventing spilling of the welding adhesive out of the overlapped leap areas (12, 13); forming a curl profile (5) at a larger diameter end (3) and a knurl profile (22) at the smaller diameter end (4) of the cup wall (2); cutting a blank of bottom (18) of a paperboard with dimensions according to a development drawings of a bottom (6); forming a sealing ring (19) of the bottom (6) by bending a partial radial portion (25) starting from the periphery of the blank (18) of the bottom (6); assembling the bottom (6) with the cup wall (2) by inserting the sealing ring (19) of the bottom (6) into the knurl profile (22) of the cup wall (2) toform a hollow truncated volume (21) for accommodating hot or cold liquid and; applying a welding adhesive in between the contact surface of the knurl profde (22) and the sealing ring (19) and curing the welding adhesive at a temperature of 260-270 °C and a pressure that is adequate for sealing of the sealing ring (19) with the knurl profile (22) preventing spilling of the welding adhesive out of an overlapped area of the sealing ring (19) and the knurl profile (22).

3. The method of manufacturing the paper cup (1) without plastic coating as claimed in claim 2, wherein a paperboard composed of 94-96% of cellulose pulp, 1-2% of starch and 2-3% of rosin without any synthetic coatings or polymers is used for the cup wall (2) and the bottom (6).

4. The method of manufacturing the paper cup (1) without plastic coating as claimed in claim 2, wherein polyolefin particles of 5-8 pm size uniformly disperse in water is used as the welding adhesive.

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