MG Kraft Paper Stretchability via Cylinder Speed Differential
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Solution Overview
Problem
There is a need for a paper-based material that can replace plastics in packaging sharp-edged products while providing sufficient puncture resistance and flexibility.
Innovation Solution
A method of producing machine-glazed (MG) kraft paper with specific rotational speed differences between cylinders in the paper machine, resulting in high stretchability and grammage, enhancing resistance to sharp-edged objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional plastic packaging is replaced with paper-based materials, then environmental concerns are addressed, but puncture resistance and suitability for sharp-edged products deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the stretchability of the paper in the machine direction (MD) to 1.8-2.8% and setting grammage to 40-65 g/m². These specific parameter ranges optimize the balance between flexibility and puncture resistance, enabling the paper to withstand sharp-edged products while maintaining environmental benefits.
Solution Approach 2:
The invention uses composite material structure by combining specific kraft paper composition with controlled mechanical properties. The paper integrates fibrous structure with optimized bonding characteristics to achieve both the required stretchability and puncture resistance, creating a composite-like performance in a single material layer.
2Strength
If paper stretchability in machine direction is increased to improve puncture resistance, then resistance to sharp-edged objects improves, but folding properties and flexibility may deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter changes by limiting the MD stretchability to a narrow range of 1.8-2.8%. This controlled parameter ensures sufficient puncture resistance while preventing excessive stiffness that would compromise folding properties. The grammage parameter (40-65 g/m²) is simultaneously optimized to maintain flexibility.
3Strength
If paper grammage is increased to improve puncture resistance, then strength against sharp edges improves, but material consumption and cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing grammage to a specific range of 40-65 g/m². This parameter optimization achieves the necessary puncture resistance for sharp-edged products while minimizing material consumption. The combination of this grammage range with controlled stretchability (1.8-2.8%) ensures efficient material usage without sacrificing strength.
Data Source
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AI summary
There is provided method of producing a machine-glazed (MG) kraft paper in a paper machine, wherein the paper is having a stretchability according to ISO 1924-3:2011 of 1.8-2.8 % in the machine direction (MD) and a grammage of 40-65 g/m2 according to ISO 536:2020, wherein - the paper machine comprises a press section and a drying section; - the press section as well as the drying section comprises cylinders; - the paper machine comprises a first open draw between a first and a second cylinder; - the first cylinder is arranged upstream of the second cylinder; and - the second cylinder rotates with a relative speed being 0.5-2.5 % faster than the first cylinder.