Continuous Glassine Paper Manufacturing With Inline Calendering

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Solution Overview

Problem

The existing method for manufacturing glassine paper requires separate machines and processes, consumes time and resources, and is inefficient due to the need for moisture stabilization and multiple calendering steps, increasing space and investment costs.

Innovation Solution

A continuous manufacturing process that integrates paper web formation, drying, film-forming product application, and on-line calendering, with adjustable heat control in the cross-direction to manage moisture and thickness profiles, using multi-nip calenders and controlled web tension to achieve desired glassine properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the base paper is dried and then re-moisturized to evening out moisture content, then the cross directional moisture profile becomes uniform, but the process consumes additional time and requires storage of machine rolls for at least 2 hours

Engineering Contradiction:
Improvemoisture content uniformityVSAvoidstorage time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by controlling the moisture content profile during the paper formation and drying stages before the paper leaves the paper machine. The cross-directional moisture profile is adjusted in the press section and pre-drying section to achieve uniform moisture distribution before calendering, eliminating the need for subsequent storage and re-moisturizing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts the moisture stabilization function from the separate offline process and integrates it into the paper machine's drying and pressing sections. By taking out the moisture control function and placing it upstream in the process, the patent eliminates the need for separate storage and re-moisturizing operations.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If separate offline supercalender machines are used to treat the base paper, then the desired glassine properties are achieved, but space requirements and investment costs increase

Engineering Contradiction:
Improveglassine paper propertiesVSAvoidspace requirement
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent merges the calendering function with the paper machine by integrating an online calendering section directly into the paper production line. This combination eliminates the need for separate offline supercalender machines and their associated storage facilities, reducing both space requirements and investment costs while maintaining the ability to produce glassine paper with desired properties.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated paper machine is designed to perform multiple functions: forming, drying, moisture profile control, and calendering all in one continuous process. This multi-functionality replaces the need for separate specialized machines, achieving space savings while maintaining manufacturing precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If multiple separate processes and machines are used for paper production and calendering, then the glassine paper properties can be achieved, but the process complexity and human resources required increase

Engineering Contradiction:
Improvepaper propertiesVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple separate processes (paper formation, drying, moisture control, and calendering) into a single integrated online process within one paper machine. This merging reduces process complexity and eliminates the need for multiple separate machines and intermediate handling operations, while still achieving the required glassine paper properties.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If the calendering speed is lower than the paper machine speed, then adequate calendering treatment can be applied, but it requires multiple separate supercalenders per paper machine

Engineering Contradiction:
Improvecalendering treatment qualityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs dynamic speed adjustment capabilities in the integrated calendering section, allowing the calendering rolls to operate at optimized speeds independent of the paper machine's line speed. This dynamic control enables adequate calendering treatment to be applied in a single inline operation, matching the paper production speed and eliminating the need for multiple separate supercalenders.

Inventive Principle:
Principle #15Dynamics

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 reduces energy consumption, eliminates the need for separate machines and storage, and achieves superior glassine paper properties with lower calendering activity, resulting in denser, smoother, and more transparent paper with improved siliconability.

Implementation Method 1

a heat transfer system capable of heating a roll surface locally and in adjustable manner in cross direction of the machine

Methodology Applied
Scientific EffectLocal heating: Heating

Implementation Method 2

application of water by condensing steam onto the web before passing the web to anyone of the calendering sections

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

drying the web in a press section and in a pre-drying section; removing moisture from the film-forming product in an after-drying section

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2931972B1A method of manufacturing of glassine paper
Publication Date: 2025.09.24 AHLSTROM OYJ
  • EP2931972B1 patent drawingFigure 1
  • EP2931972B1 patent drawingFigure 2
  • EP2931972B1 patent drawingFigure 3

AI summary

Invention relates to a method of manufacturing of glassine paper comprising following steps of producing paper by forming a pa- per web in a forming section (12) and drying the web in a press section (14) and in a pre-drying section (16); applying film- forming product on both sides of the web (18); removing moisture from the film-forming product in an after-drying section (20); passing the web having film-forming product on its surfaces through an on-line calendering process (22); and reeling up the glassine paper (24).