Urea Formaldehyde Scavenger Microcapsule Colour Stability
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Solution Overview
Problem
Treatment compositions containing perfume microcapsules often exhibit poor colour stability due to residual formaldehyde and its slow release, leading to discoloration, especially when using formaldehyde scavengers with activated methylene groups that form coloured complexes with perfume aldehydes and ketones.
Innovation Solution
The use of urea as a formaldehyde scavenger in microcapsule formulations, which does not contain an activated methylene group, to prevent discoloration by scavenging free formaldehyde and reducing the porosity of microcapsule walls, thereby maintaining colour stability and extending the odour benefit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If formaldehyde scavengers with activated methylene groups are used to control formaldehyde levels, then formaldehyde release is reduced, but discoloration occurs due to coloured complex formation with perfume aldehydes and ketones
Solution Approach 1:
The patent introduces urea as an intermediary substance that mediates between formaldehyde control and colour stability. Urea scavenges formaldehyde through a different mechanism that does not involve activated methylene groups, thereby preventing the formation of coloured complexes with perfume aldehydes and ketones while still maintaining acceptable formaldehyde levels.
Solution Approach 2:
The patent changes the chemical parameter of the formaldehyde scavenger from compounds with activated methylene groups to urea, which has different chemical properties. This parameter change allows formaldehyde scavenging to occur without the side reaction of forming coloured complexes, thus resolving the contradiction between formaldehyde control and colour stability.
2Duration of action of moving object
If microcapsules are used to encapsulate perfume raw materials, then long-lasting odour benefit is achieved, but residual formaldehyde slowly releases causing poor colour stability
Solution Approach 1:
Urea acts as an intermediary within the treatment composition that addresses the formaldehyde release issue from microcapsules. By scavenging the slowly released formaldehyde without forming coloured complexes, urea allows the microcapsules to maintain their long-lasting odour benefit while preventing the associated colour instability.
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 use of urea as a formaldehyde scavenger in microcapsule formulations enhances colour stability and maintains the aesthetic appearance of treatment compositions over time, while providing a long-lasting woody, floral, fruity, or citrus character to treated substrates without significant discoloration.
Implementation Method 1
a formaldehyde scavenger wherein the formaldehyde scavenger is urea
Implementation Method 2
reducing the porosity of microcapsule walls
Implementation Method 3
the microcapsule wall is formed by cross-linking formaldehyde with at least one other monomer
Data Source
AI summary
The need for a treatment composition which provides a pleasant odour to a treated situs, particularly one having a long-lasting woody, floral, fruity or citrus character, and which does not discolour over time, is met by formulating the treatment composition with microcapsules comprising a microcapsule wall formed from cross-linked formaldehyde, and a core comprising an aldehyde or ketone containing perfume, in combination with a formaldehyde scavenger which does not complex with the aldehyde and/or ketone and amine, to form complexes that result in discoloration.