Translucent Paper Composition for Drainable Food Packaging
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Solution Overview
Problem
Existing paper manufacturing processes struggle to produce translucent paper products with sufficient transparency and barrier properties for food packaging without extensive refining or additional machinery, particularly when incorporating microfibrillated cellulose.
Innovation Solution
A translucent paper is created by combining pulp fibers with a high Schopper-Riegler (SR) value and microfibrillated cellulose in specific proportions, processed on existing paper machines, enhancing transparency and barrier properties through a unique papermaking process involving rewetting and supercalendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pure microfibrillated cellulose is used to create transparent film, then transparency and barrier properties are improved, but manufacturing complexity increases due to extensive hardware adjustments and additional machinery
Solution Approach 1:
The patent uses composite materials by combining microfibrillated cellulose (MFC) with conventional paper pulp fibers in a furnish mixture. This composite approach allows the paper machine to produce translucent paper with good barrier properties without requiring pure MFC processing equipment, thus reducing hardware complexity while maintaining transparency and barrier performance.
2Illumination intensity
If microfibrillated cellulose is deposited on the paper machine wire, then transparent film can be produced, but water drainage becomes difficult due to water retention
Solution Approach 1:
The patent achieves homogeneity by thoroughly mixing microfibrillated cellulose with conventional paper pulp fibers in the furnish before deposition. This homogeneous mixture prevents MFC from clumping and excessive water retention, allowing proper drainage on the paper machine wire while maintaining the transparency benefits of MFC throughout the paper structure.
3Illumination intensity
If paper pulp is extensively refined to increase transparency, then translucency improves, but energy consumption and processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-processing the pulp into microfibrillated cellulose form before it reaches the paper machine. This pre-fibrillation allows the material to achieve high transparency with minimal additional refining energy at the paper machine, as the MFC structure is already optimized for light transmission before deposition.
4Illumination intensity
If refiners are used to refine paper pulp, then transparency increases within a limited range, but the paper mill remains constrained by the refiners' limited refining capacity
Solution Approach 1:
The patent applies parameter changes by fundamentally altering the fiber structure parameter through microfibrillation before papermaking. Instead of relying on refiners to achieve transparency within their limited refining range, the MFC conversion changes the physical state of the cellulose to a highly fibrillated form that inherently provides superior transparency with minimal additional refining required.
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 resulting paper achieves high transmittance and grease resistance, meeting the requirements for food packaging without the need for extensive refining or additional machinery, while maintaining operational efficiency.
Implementation Method 1
after pressing and drying, the paper web is passed through a stack of alternating steel- and fiber-covered rolls of the supercalender at the end of the paper machine so that the paper fibers flatten facing in the same direction
Implementation Method 2
if the furnish comprising essentially only microfibrillated cellulose is deposited on the moving woven mesh of the paper machine to create a continuous web of microfibrillated cellulose, it is challenging to drain the furnish of its water
Data Source
AI summary
A translucent paper comprising a base paper layer, and optionally a coating layer adjacent to the base paper layer, wherein the base paper layer comprises a mixture of wood pulp fiber and microfibrillated cellulose, characterized in that the pulp fiber has a degree of Schopper-Riegler (SR) of more than or equal to 50 SR and that the microfibrillated cellulose is comprised in the mixture of pulp fiber and microfibrillated cellulose in an amount of 10 weight percent to about 50 weight percent, based on the weight of the mixture of pulp fiber and microfibrillated cellulose and wherein the mixture of pulp fiber and microfibrillated cellulose has a degree of Schopper-Riegler (SR) of between 65 SR and 95 SR, preferably of between 70 SR and 90 SR, as measured under ISO 5267-1.