Cellulose fibre-based support containing a modified PVA layer, and a method for its production and use

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Solution Overview

Problem

Existing cellulose fibre-based supports for siliconizing face challenges in achieving optimal silicone anchorage and cross-linking while minimizing silicone penetration and catalyst usage, particularly with low-temperature curing silicones, which often result in low anchorage and high costs.

Innovation Solution

Functionalizing a water-soluble polymer with vinylic and aldehyde functionalities through an acetalization reaction before coating it on the cellulose support, enabling better silicone anchorage and cross-linking, and reducing the amount of silicone and catalyst required during the siliconization process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If low-temperature curing silicones are used to reduce energy consumption and simplify the process, then curing temperature is reduced, but silicone anchorage on the support deteriorates

Engineering Contradiction:
Improvecuring temperatureVSAvoidsilicone anchorage
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The support surface is pre-modified with silane coupling agents before silicone application. This preliminary action creates reactive sites on the support surface that enable strong chemical bonding with the silicone, ensuring good anchorage even when curing is performed at low temperatures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The chemical composition and surface properties of the support are modified by introducing silane functional groups. This parameter change in the support's surface chemistry enables it to form strong bonds with low-temperature curing silicones, resolving the anchorage problem associated with reduced curing temperatures.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the support structure is modified to improve silicone anchorage, then anchorage is enhanced, but the complexity of the support structure increases

Engineering Contradiction:
Improvesilicone anchorageVSAvoidsupport structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The modification is applied locally to the support surface rather than throughout the entire support structure. Only the surface layer is treated with silane coupling agents, which provides the necessary anchorage functionality without altering the bulk properties or overall simplicity of the support structure.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional coating methods are used to apply the binding agent layer, then the process is simple, but the surface regularity and homogeneity are insufficient for optimal silicone application

Engineering Contradiction:
Improvecoating process simplicityVSAvoidsurface regularity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A size press is introduced as an intermediary device between the coating process and the final support product. The size press passes the coated support through rollers that apply controlled pressure, ensuring uniform surface regularity and homogeneity without significantly complicating the overall manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enhances silicone anchorage and cross-linking, allowing for a significant reduction in silicone and catalyst usage, improving the support's barrier properties and maintaining anchorage even in hot, humid conditions, while maintaining effective silicone coverage and stability.

Implementation Method 1

Functionalizing a water-soluble polymer with vinylic and aldehyde functionalities through an acetalization reaction before coating it on the cellulose support

Methodology Applied
Scientific EffectAcetalization reaction: Chemical Bonding

Implementation Method 2

enabling better silicone anchorage and cross-linking

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Data Source

PatentEP2539505B2Cellulose fibre-based support containing a modified PVA layer, and a method for its production and use
Publication Date: 2021.09.01 AHLSTROM OYJ
  • EP2539505B2 patent drawingFigure 1
  • EP2539505B2 patent drawingFigure 2~3
  • EP2539505B2 patent drawingFigure 4~5

AI summary

A cellulose fibre-based support of which at least one surface is coated with a layer containing at least one water-soluble polymer having hydroxyl functions, at least some of which have been reacted beforehand with at least one organic molecule that contains at least one vinylic function, characterized in that said organic molecule also has an aldehyde function. Method for production thereof.