Cellulose Ether Surface Sizing for Humidity-Resistant Board Strength
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Solution Overview
Problem
Fibrous packaging materials, such as corrugated board, suffer from poor moisture resistance and compression strength, especially in humid conditions, limiting their use in packaging applications.
Innovation Solution
Applying a surface size composition containing cellulose ethers, excluding carboxyalkyl celluloses, to enhance the compression strength and moisture resistance of fibrous webs like paper and board, particularly in high humidity environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If starch-based surface sizing is used to enhance mechanical strength of board, then compression strength is improved, but moisture resistance deteriorates in humid conditions
Solution Approach 1:
The patent changes the chemical parameters of the surface sizing agent from starch to cellulose derivative, specifically modifying the hydrophilic-hydrophobic balance through controlled substitution. This parameter change allows the material to maintain compression strength while improving moisture resistance in humid conditions.
Solution Approach 2:
The patent creates a composite surface sizing material by combining cellulose derivative with specific hydrophobic groups. This composite structure integrates the strength-providing capability of cellulose with the moisture-resistant properties of hydrophobic groups, resolving the contradiction between compression strength and moisture resistance.
2Reliability
If protective polyethylene film is applied to board surface, then moisture resistance is improved, but cost efficiency and recyclability deteriorate
Solution Approach 1:
The patent extracts the essential function of the polyethylene film (moisture resistance) and transfers it to a cellulose-based surface sizing agent that can be applied directly to the board surface. This eliminates the need for separate protective films, reducing cost and improving recyclability while maintaining moisture resistance.
Solution Approach 2:
The cellulose derivative surface sizing agent performs multiple functions simultaneously: it provides mechanical strength enhancement, moisture resistance, and maintains recyclability. This multi-functionality replaces the need for separate protective films, improving cost efficiency while maintaining reliability.
3Adaptability or versatility
If cellulose-based fibres are used to provide mechanical strength, then renewable origin and recyclability are improved, but water and moisture resistance deteriorates due to hydrophilic hydroxyl groups
Solution Approach 1:
The patent applies local quality modification by introducing hydrophobic groups at specific locations on the cellulose derivative molecules. This allows the bulk cellulose structure to maintain its renewable and recyclable properties while the modified regions provide the necessary moisture resistance.
Data Source
AI summary
The invention relates to the use of a surface size composition comprising at least one cellulose derivative selected from cellulose ethers, excluding carboxyalkyl celluloses, for providing compression strength for a fibrous web, such as paper, board or the like, preferably comprising recycled cellulosic fibres. The invention relates also to a method for surface sizing of paper, board or the like.