Flat-Rim Paper Cup Sealing With Local Heat Seal Lacquer
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Solution Overview
Problem
Existing methods for manufacturing paper cups with a flat rim struggle with forming a stable rim using single-side polyethylene coated paper board due to the lack of heat-sealing properties on one surface, which hinders the proper connection of layers during the flattening process.
Innovation Solution
A method involving a single-side barrier material coated paper blank with a heat seal lacquer applied to the top portion of the second surface, combined with a two-step curling and flattening process, ensures heat-sealing properties are provided where needed, allowing for a stable flat rim formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If single-side polyethylene coated paper board is used to reduce plastic quantity, then the amount of barrier material is reduced, but heat-sealing properties are insufficient on one surface preventing proper layer connection
Solution Approach 1:
The patent applies heat seal lacquer locally only to the top portion of the second surface where the flat rim will be formed, rather than coating the entire surface. This localized application provides heat-sealing properties exactly where needed for layer connection during rim formation, while avoiding unnecessary material usage on other parts of the cup body.
Solution Approach 2:
The heat seal lacquer acts as an intermediary substance that enables heat-sealing between layers of the paper board. Since single-side coated paper lacks heat-sealing properties on the second surface, the lacquer mediates the bonding process by providing the necessary adhesive and sealing characteristics during the flattening operation.
2Reliability
If double-side polyethylene coated paper board is used to ensure heat-sealing properties on both surfaces, then heat-sealing properties are sufficient for stable flat rim formation, but the amount of barrier material increases
Solution Approach 1:
Instead of uniformly coating both surfaces of the paper board with barrier material, the patent uses single-side coating combined with localized heat seal lacquer application. This creates different functional zones: the first surface has barrier properties for moisture protection, while the top portion of the second surface has heat-sealing properties for rim formation, eliminating the need for full double-side coating.
Solution Approach 2:
The patent segments the functional requirements of the paper board into distinct zones: moisture barrier function on the first surface, and heat-sealing function on the top portion of the second surface. This segmentation allows each surface to be optimized for its specific function rather than requiring both surfaces to have both properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of paper cups with a reduced amount of barrier material while maintaining stability and integrity of the flat rim, reducing material and production costs.
Implementation Method 1
applying a heat seal lacquer in a top portion of the second surface of the blank, the top portion being intended to form the flat rim of the cup
Implementation Method 2
the first surface is covered with the barrier material coating
Data Source
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AI summary
The invention concerns a method for manufacturing a cup (1) having a flat rim (4) for attaching a cover, comprising the following method steps: providing a single-side barrier material coated paper blank (100) for forming a side wall (2) of the cup (1), wherein the blank (100) has a first surface (101) adapted to form the inside of the side wall (2) and a second surface (102) adapted to form the outside of the side wall (2), wherein the first surface (101) is covered with the barrier material coating, applying a heat seal lacquer (103) in a top portion (112) of the second surface of the blank (100), the top portion (112) being intended to form the flat rim (4) of the cup (1); forming the side wall (2) of the cup (1) by joining two edges of the blank (100) along a side seam, providing a bottom (3) and joining the bottom (3) with the side wall (2) such that the top portion (112) is arranged at a top edge (22) of the side wall (2) facing away from the bottom (3); curling the top edge (22) of the side wall (2) thereby forming a curled rim, wherein the heat seal lacquer (103) is arranged on an inner surface of the curled rim; flattening the curled rim thereby forming a flat rim (4).