Wet Papermaking Window Formation Using Convergent Fluid Jets
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Solution Overview
Problem
Existing paper manufacturing techniques face challenges in creating transparent windows without causing paper deformation and excess thickness, particularly due to mechanical and water absorption differences between paper and plastic films, and require high energy for fluid pressure in forming windows.
Innovation Solution
A wet papermaking process involving two layers of fibers, where a pressurized fluid is used to create a continuous longitudinal window by orienting jets convergently to form an angle less than 90°, reducing energy consumption and maintaining visual quality of border zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plastic film is deposited on the paper support to seal the window, then mechanical resistance and security are improved, but paper deformation and curling occur due to different mechanical properties and water absorption
Solution Approach 1:
The patent removes the plastic film sealing layer entirely, replacing it with a window formed directly in the paper structure. The window is created by removing a longitudinal ribbon of fibrous material from one layer, allowing light transmission without introducing incompatible materials that cause deformation.
Solution Approach 2:
The patent applies localized thinning by removing only a longitudinal ribbon of fibrous material from one layer, creating a window with specific optical properties while maintaining the structural integrity of the rest of the paper. This localized modification avoids the need for plastic film sealing.
2Adaptability or versatility
If a plastic film is deposited on the paper support, then security elements can be accommodated, but excess thickness is created on the paper reels
Solution Approach 1:
The patent eliminates the plastic film layer that causes excess thickness by creating the window directly in the paper structure. The window is formed by removing fibrous material, resulting in minimal thickness variation without compromising security element accommodation.
Solution Approach 2:
The patent creates a localized window by removing only a longitudinal ribbon of fibrous material, maintaining constant thickness in the rest of the paper. This localized thinning allows security elements to be accommodated without creating excess thickness on the paper reels.
3Manufacturing precision
If high pressure fluid is used to form windows in multi-layer paper, then window formation is achieved, but high energy consumption occurs
Solution Approach 1:
The patent forms the window by removing a longitudinal ribbon of fibrous material through a simple cutting or separation process, rather than using high-pressure fluid. This extraction method requires minimal energy compared to high-pressure fluid systems.
Solution Approach 2:
The patent replaces the high-pressure fluid mechanical system with a simpler mechanical cutting or separation process. The window is formed by physically removing the fibrous ribbon, eliminating the need for energy-intensive high-pressure fluid application.
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
This method efficiently forms transparent windows with minimal deformation and energy usage, achieving a paper product with reduced thickness and excellent visual quality at the border zones.
Implementation Method 1
removal is carried out using a pressurized fluid, between said forming and assembly sections, of at least one longitudinal ribbon of fibrous material
Data Source
Figure 1
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Figure 4~6
AI summary
The present invention relates in particular to a method for manufacturing a material (6) consisting of fibers and formed into a strip, by wet papermaking, this material (6) being multilayered and comprising a first layer (4) of fibers and at least a second layer (5) of fibers bonded together, a method in which each layer of fibers (4, 5) is formed individually by draining on a forming cloth (3) in a forming section (1), then conveyed in a strip to an assembly section (2) in which said layers (4, 5) are assembled to form the multilayer material (6), and then to a pressing and drying section, characterized in that at least one longitudinal ribbon (R) of fibrous material is removed, using a pressurized fluid, between said forming (1) and assembly (2) sections, from only one (4) of said layers (4,5) so as to form a continuous longitudinal window, that two jets (J) of pressurized fluid are used for each longitudinal strip, which are positioned so as to delimit the opposite edges (40) of said longitudinal window (F), and that said jets (J) are oriented convergently, namely that they are oriented towards the center of said longitudinal strip (R) to be removed, so as to form with the plane in which said strip is contained an angle x° less than 90°, in particular between 45° and 90°, preferably between 45° and 85° and more preferably between 50° and 75°.