Phosphorylated Ultrafine Cellulose Fibers With Low Yellowing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing ultrafine cellulose fibers with phosphorous acid groups face issues of yellowing and reduced transparency due to prolonged phosphorylation treatments, leading to unintentional dissociation of phosphorous acid groups.
Innovation Solution
A method involving multiple phosphorylation steps with controlled urea decomposition percentage, heat treatment times, and molar ratios to introduce phosphorous acid groups effectively, enhancing transparency while suppressing yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the phosphorylation treatment time is extended to introduce a large number of phosphorous acid groups into cellulose fibers, then the amount of phosphorous acid groups increases, but the phosphorous acid groups dissociate unintentionally and the fibers turn yellow
Solution Approach 1:
The phosphorylation treatment is divided into multiple sequential steps rather than one prolonged treatment. Each step introduces phosphorous acid groups in a controlled manner, preventing dissociation while achieving the desired total amount of groups on the fibers
Solution Approach 2:
Urea is applied as a preliminary action before phosphorylation treatment. Urea forms inclusion complexes with phosphorous acid, stabilizing it during the treatment process and preventing unwanted dissociation, thereby allowing extended treatment time without losing the phosphorous acid groups
2Quantity of substance
If the phosphorylation treatment time is extended to introduce phosphorous acid groups, then the functional groups are introduced, but the transparency of the composition decreases
Solution Approach 1:
Dividing the phosphorylation into multiple steps prevents excessive treatment that would cause yellowing, thereby maintaining the transparency of the final composition while still achieving sufficient functional group introduction
Solution Approach 2:
Urea treatment as a preliminary step stabilizes phosphorous acid and enables controlled introduction of functional groups without the side effects of prolonged treatment, preserving optical properties
3Productivity
If mechanical treatment is performed to produce ultrafine cellulose fibers, then the fibers are obtained, but enormous energy is required due to strong hydrogen bonding between fibers
Solution Approach 1:
Chemical treatment with phosphorous acid and urea is performed as a preliminary action before mechanical treatment. This pre-treatment modifies the fiber surface and weakens hydrogen bonding, thereby reducing the energy required for subsequent mechanical fibrillation
Solution Approach 2:
The chemical composition and surface properties of the cellulose fibers are changed through phosphorylation treatment, altering the intermolecular forces and making the fibers easier to separate mechanically with lower energy input
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 method achieves enhanced transparency and suppresses yellowing of ultrafine cellulose fibers by optimizing the phosphorylation process, resulting in high transparency and stability of compositions containing these fibers.
Implementation Method 1
a step of mixing a compound having a phosphorous acid group and/or a salt thereof and urea and/or a urea derivative into a cellulose raw material so as to introduce the phosphorous acid group into the cellulose raw material
Implementation Method 2
it has become clear that, in order to stably maintain the phosphorous acid groups, it is effective to use urea and/or a urea derivative which form an inclusion complex with phosphorous acid
Implementation Method 3
electrical repulsion is generated between ions and also, the ions are hydrated, so that dispersibility in an aqueous solvent can be significantly improved
Implementation Method 4
electrical repulsion is generated between ions and also, the ions are hydrated, so that dispersibility in an aqueous solvent can be significantly improved
Data Source
Figure 1
AI summary
The present invention is intended to enhance the transparency of a composition obtained using ultrafine cellulose fibers having phosphorous acid groups, while suppressing the yellowing of the ultrafine cellulose fibers. The present invention relates to cellulose fibers having a fiber width of 1000 nm or less and having a phosphorus oxoacid group or a phosphorus oxoacid group-derived substituent, wherein when a first amount of dissociated acid in the cellulose fibers is set to be A1 and a total amount of dissociated acid in the cellulose fibers is set to be A2, A1 is 1.35 mmol/g or more, and the value of A1/A2 is 0.51 or more, and when a sheet is formed under a predetermined condition, the YI value of the sheet is 6.0 or less.