Optical Brightener Salt Solutions for Storage Stability
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Solution Overview
Problem
The paper and board industry requires stable, concentrated aqueous solutions of optical brighteners without solubilizing auxiliaries, as existing solutions often contaminate effluent and lack storage stability across temperature ranges.
Innovation Solution
Aqueous solutions of specific salt forms of anilino-substituted bistriazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulphonic acid combined with small amounts of organic acids, such as citric, glycolic, or formic acid, create stable solutions without the need for solubilizing additives, and a process involving conversion of these compounds to mixed salt forms using 2-dimethylaminoethanol and organic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If solubilizing auxiliaries such as urea or ethylene glycol are added to provide stable aqueous solutions, then storage stability is improved, but contamination of effluent increases and environmental impact worsens
Solution Approach 1:
The patent extracts and eliminates the harmful solubilizing auxiliaries (urea, ethylene glycol) from the formulation while maintaining storage stability through the use of the optical brightener itself as a hydrate, which provides stability without environmental contamination
Solution Approach 2:
The optical brightener compound serves dual functions: it provides the whitening effect and simultaneously acts as its own solubilizing agent through hydrate formation, eliminating the need for separate solubilizing auxiliaries and their associated environmental problems
2Productivity
If concentrated aqueous solutions are prepared to improve ease of handling and metering, then productivity is improved, but storage stability across wide temperature ranges deteriorates
Solution Approach 1:
The patent changes the physical state parameter of the optical brightener by forming a hydrate structure, which allows the compound to remain stable in concentrated aqueous solutions across wide temperature ranges (4-50°C) without precipitation or degradation, thus maintaining both concentration and stability
3Stability of the object's composition
If solubilizing agents are added to maintain solution stability, then storage stability is improved, but device complexity increases due to multiple additives
Solution Approach 1:
The patent removes multiple solubilizing additives from the formulation and relies solely on the hydrate form of the optical brightener itself to provide stability, significantly simplifying the formulation while maintaining solution stability
Solution Approach 2:
The optical brightener compound performs multiple functions simultaneously: it provides the whitening effect, forms hydrates for stability, and eliminates the need for separate solubilizing agents, thereby reducing formulation complexity
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 solutions demonstrate improved storage stability and compatibility with cellulose fibers, maintaining effectiveness across temperature ranges and reducing contamination, as shown in examples where solutions remain stable for weeks without precipitating.
Implementation Method 1
certain hydrates of (A, including M=Na) may be used to produce stable liquid suspensions or slurries containing low amounts of formulation auxiliaries
Implementation Method 2
a specific salt form of (A) in combination with small amounts of organic acids enables stable concentrated solutions to be formed
Data Source
AI summary
The instant invention relates to storage stable solutions of optical brighteners based on certain salt forms of anilino-substituted bistriazinyl derivatives of 4,4'-diaminostilbene- 2,2'-disulphonic acid and of organic acids which do not need extra solubilising additives.