Spray-Dried Detergent Particle Neutralization Process
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Solution Overview
Problem
Existing laundry detergent compositions are harsh on the skin due to excess alkalinity and suffer from reduced cleaning performance and powder properties when attempting to minimize alkaline ingredients like sodium carbonate and sodium silicate, which are essential for buffering and builder functions.
Innovation Solution
A process involving partial neutralization of anionic surfactant acid precursors with alkali metal hydroxide followed by further neutralization with a silicate agent, balancing the neutralization to achieve 10-98% of the anionic surfactant content, reducing unreacted sodium hydroxide and maintaining alkaline builder levels, thereby achieving lower reserve alkalinity and improved skin gentleness without compromising cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If alkaline ingredients such as sodium carbonate and sodium silicate are significantly reduced or completely removed to provide mildness to the skin, then skin mildness is improved, but cleaning performance and powder properties such as free-flowability and storage stability deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific mildness-providing ingredients (glycine, alanine, or serine) at controlled concentrations (0.1-5% w/w) to reduce skin harshness while maintaining cleaning performance. It also optimizes the pH range (9.0-11.0) and controls the content of alkaline builders to achieve the desired balance between mildness and effectiveness.
Solution Approach 2:
The patent creates a composite detergent formulation that combines multiple functional components: anionic surfactants (40-70% w/w), mildness-providing ingredients (glycine/alanine/serine) at 0.1-5% w/w, controlled amounts of alkaline builders, and optional auxiliary ingredients. This composite approach allows the detergent to simultaneously provide cleaning performance, skin mildness, and stable powder properties.
2Object-affected harmful factors
If alkaline ingredients are reduced to provide mildness, then skin gentleness is improved, but buffering capacity and builder functions deteriorate
Solution Approach 1:
The patent carefully controls the pH parameter within the range of 9.0-11.0 and limits alkaline builder content to 1-20% w/w, which provides sufficient buffering capacity while reducing skin harshness. The introduction of amino acids (glycine, alanine, or serine) at 0.1-5% w/w contributes to pH stabilization and buffering without the harsh effects of high alkaline content.
3Reliability
If unreacted sodium hydroxide is present in the spray-dried particle, then neutralization completeness is improved, but skin harshness increases
Solution Approach 1:
The patent controls the neutralization process to achieve complete reaction of sodium hydroxide with acid precursors, ensuring no unreacted NaOH remains in the final product. The pH is maintained within 9.0-11.0, which indicates complete neutralization while providing sufficient alkalinity for cleaning performance without the harshness associated with excess unreacted base.
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 process results in a spray-dried detergent particle with reduced harshness on hands, maintained cleaning performance, and improved powder properties, including reduced caking tendency and extended shelf life, while maintaining a pH between 10.5 and 11.5.
Implementation Method 1
mixing an acid precursor of an anionic surfactant and an alkali metal hydroxide neutralizing agent in an aqueous medium to form a partially neutralized solution, wherein the partially neutralised solution comprises an anionic surfactant salt formed in-situ by the reaction of a portion of acid anionic surfactant precursor with the alkali metal hydroxide neutralizing agent
Implementation Method 2
spray-drying the aqueous detergent slurry to form a spray-dried detergent particle
Data Source
AI summary
The present invention relates to a process for preparing of a particulate, free flowing detergent particle by a slurry making and spray drying technique. It is an object of the present invention to provide a process for preparing a detergent solution which upon spray-drying provides a spray-dried particle having lower reserve alkalinity and which is less harsh on hands and provides good fabric care performance. The present inventors have found a way to provide a free-flowing spray-dried detergent particle which is gentle on hand, gives good fabric care performance, good fabric cleaning performance and which also retains good powder properties by providing a process of preparing a detergent solution which yields lower reserve alkalinity in the spray-dried particle and has a pH preferably from 10.5 to 11.5 and preferably without impacting the current level of alkaline builders such as sodium carbonate and sodium silicate in the composition.