Optical Brightener Salt Formulation for Stable Aqueous Solutions
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Solution Overview
Problem
The paper and board industry requires stable, concentrated aqueous solutions of optical brighteners for improved whiteness and handling, but existing solutions often rely on solubilizing auxiliaries that contaminate effluent and lack storage stability without these additives.
Innovation Solution
A specific salt form of anilino-substituted bistriazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulphonic acid is used to create stable, concentrated solutions without additional solubilizing agents, achieved through a process involving conversion to a mixed salt form using 2-dimethylaminoethanol and mineral acids, followed by membrane filtration to remove excess salts and alkanolamines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solubilising auxiliaries such as urea or ethylene glycol are added to optical brightener solutions, then storage stability is improved, but effluent contamination increases and the solution contains substances with no affinity for cellulose
Solution Approach 1:
The invention extracts and eliminates the need for solubilising auxiliaries from the optical brightener solution. By formulating a solution of the optical brightener in water without adding urea, ethylene glycol, or other solubilising agents, the patent removes the source of effluent contamination while maintaining storage stability through proper salt selection and concentration control.
Solution Approach 2:
The invention changes the chemical parameters of the solution by selecting specific salt forms of the optical brightener (sodium, ammonium, or organic amine salts) and controlling the concentration and pH. This parameter optimization allows the solution to achieve storage stability without requiring additional solubilising additives that would contaminate effluent.
2Ease of operation
If optical brighteners are supplied as concentrated aqueous solutions, then ease of handling and metering is improved, but storage stability over wide temperature ranges becomes difficult to achieve without solubilising additives
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: salt type (sodium, ammonium, or organic amine), salt concentration, pH level, and temperature range. By carefully balancing these parameters, the solution achieves both concentrated formulation (for ease of handling) and storage stability (for reliability) without requiring additional solubilising agents.
Solution Approach 2:
The invention creates a composite aqueous solution system where the optical brightener exists in a specific salt form that combines the properties of water solubility and thermal stability. This composite formulation integrates the brightener molecule with appropriate counter-ions to achieve both ease of handling as a concentrated solution and storage stability across wide temperature ranges.
3Adaptability or versatility
If anilino-substituted bistriazinyl derivatives with high cellulose affinity are used, then suitability for wet-end application is improved, but ability to form stable concentrated aqueous solutions without solubilising auxiliaries deteriorates
Solution Approach 1:
The invention changes the ionization state and salt form parameters of the anilino-substituted bistriazinyl derivative. By converting the brightener to specific salt forms (particularly organic amine salts like triethanolamine or diethanolamine salts) and controlling the pH and concentration, the patent enables these high-affinity compounds to form stable concentrated aqueous solutions without requiring additional solubilising auxiliaries.
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 resulting solutions exhibit high storage stability and ease of application, maintaining whiteness and compatibility with cellulose-based products, as demonstrated by examples showing stability over wide temperature ranges and effective whitening performance in paper and board applications.
Implementation Method 1
a specific salt form of anilino-substituted bistriazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulphonic acid is used to create stable, concentrated solutions without additional solubilizing agents
Implementation Method 2
followed by membrane filtration to remove excess salts and alkanolamines
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 of formula (I) wherein R , R1 , R2 , M+ and n are as defined in the description, which do not need extra solubilising additives.