Release Paper Using Nano-Fibrillated Cellulose for Low Air Permeability
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Solution Overview
Problem
The manufacturing of release base papers requires high energy usage and costs due to the need for low freeness pulps, which slow down paper machine productivity and increase energy consumption, and the use of petrochemical-based coatings that are costly and not easily recyclable.
Innovation Solution
Incorporating nano-fibrillated cellulose into the paper-making furnish or coating process, with concentrations ranging from 10 to 400 lbs/ton, to produce release base papers with improved strength, smoothness, and low air permeability, reducing the need for extensive refining and petrochemical coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low freeness pulps are used to produce release base papers with low air permeability, then air permeability is reduced, but paper machine productivity decreases and energy consumption increases
Solution Approach 1:
The patent applies parameter changes by modifying the freeness of the pulp furnish from conventional low values (100-200 ml) to high values (300-600 ml or higher), fundamentally changing the processing parameters to achieve both high productivity and low air permeability through the synergistic effect of high freeness pulp combined with nano-fibrillated cellulose and/or plasticizer coatings
Solution Approach 2:
The patent uses composite materials by combining high freeness pulp with nano-fibrillated cellulose (NF) and/or plasticizer coatings to create a composite structure that achieves low air permeability without requiring heavy refining. The NF particles and plasticizers work together with the high freeness pulp fibers to fill voids and reduce permeability while maintaining drainage efficiency
2Reliability
If low freeness pulps are used to achieve low air permeability, then air permeability is reduced, but energy consumption increases
Solution Approach 1:
The patent changes the freeness parameter from conventional low values to high values (300-600+ ml), eliminating the need for energy-intensive heavy refining operations. The high freeness pulp combined with NF and plasticizer coatings achieves low air permeability without the energy penalty of extensive mechanical refining
Solution Approach 2:
The patent employs cost-effective nano-fibrillated cellulose and plasticizer coatings as additive materials that can be applied in controlled amounts to high freeness pulp. These additives provide the air permeability control function without requiring expensive, energy-intensive heavy refining processes
3Manufacturing precision
If petrochemical-based coatings are used to achieve smooth finish and coating holdout, then surface quality is improved, but manufacturing cost increases and recyclability decreases
Solution Approach 1:
The patent changes the material composition parameter by replacing petrochemical-based coatings with bio-based alternatives including nano-fibrillated cellulose and plasticizers derived from renewable resources. This substitution maintains surface quality and coating holdout properties while reducing manufacturing costs and improving environmental performance
Solution Approach 2:
The patent achieves homogeneous surface properties by combining NF particles with plasticizer coatings on high freeness pulp, creating a uniform surface structure that provides consistent smoothness and coating holdout. The homogeneous distribution of NF and plasticizer ensures uniform performance across the paper surface
4Reliability
If heavily refined pulps are used to achieve low air permeability, then air permeability is reduced, but dimensional stability decreases
Solution Approach 1:
The patent fundamentally changes the freeness parameter from low (conventional) to high (300-600+ ml), which preserves fiber length and bonding capacity. This parameter change, combined with NF and plasticizer additives, achieves low air permeability while maintaining excellent dimensional stability that is lost in heavily refined pulps
Data Source
AI summary
Release base papers with improved surface properties and more efficient manufacturing potential are made using cellulose nanofibrils (CNF) along with high freeness, less refined pulp. Release papers serve as the backing for common adhesive labels, for industrial film coatings, and also for certain food processing uses. The CNF may be added to the furnish and processed to paper, or the CNF may be added as a coating onto a partially dried web of paper. The CNF may optionally be combined with a starch and a starch crosslinker.