pH-Independent Microcapsule Shell via Monomer Blend
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Solution Overview
Problem
Existing microcapsules fail to display satisfactory pH-independent shell properties, leading to high leakage levels and loss of olfactive properties, especially in liquid household, laundry, and cosmetic products with varying pH ranges.
Innovation Solution
A microcapsule with a polymeric shell comprising a blend of monomers, including 2-hydroxyethyl methacrylate, methyl methacrylate, and a polyethylenically unsaturated monomer, which provides pH-independent shell properties and reduced fragrance leakage, even in acidic and alkaline conditions, through a free radical polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing microcapsules are used in liquid products with varying pH ranges, then they can be applied in diverse consumer products, but they exhibit high leakage levels and loss of olfactive properties due to unsatisfactory pH-independent shell properties
Solution Approach 1:
The patent applies composite materials by creating a polymeric shell composed of a specific copolymer blend containing at least 50-90 wt% neutral monomethacrylate monomer (Ia), 0-50 wt% neutral monoethylenically unsaturated monomer (Ib), 0-15 wt% ionized or ionizable monoethylenically unsaturated monomer (Ic), and 5-90 wt% polyethylenically unsaturated monomer (II). This composite polymer structure combines materials with different pH response characteristics to achieve overall pH independence, resolving the contradiction between adaptability to diverse pH conditions and maintenance of shell integrity.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the composition ratios of multiple monomer components in the copolymer shell. Specifically, it optimizes the weight percentages of neutral monomers (Ia, Ib), ionized monomers (Ic), and polyethylenically unsaturated monomers (II) to create a shell whose physical and chemical properties remain stable across pH 2-12. This compositional parameter optimization enables the shell to maintain its integrity while adapting to varying pH environments.
2Reliability
If the polymeric shell composition is optimized for pH independence, then fragrance leakage is reduced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing all required monomer components (Ia, Ib, Ic, and II) in the precise weight ratios specified before initiating polymerization. The monomers are combined with the fragrance composition and emulsifier in advance to form a homogeneous monomer blend, which simplifies the manufacturing process by eliminating the need for complex stepwise addition or post-polymerization adjustments. This preliminary preparation ensures the correct copolymer composition is achieved while maintaining manufacturing simplicity.
3Strength
If a higher proportion of crosslinking monomer is used, then shell strength increases, but fragrance leakage increases due to reduced pH independence
Solution Approach 1:
The patent applies parameter changes by precisely controlling the proportion of polyethylenically unsaturated monomer (II) within 5-90 wt% of the total copolymer composition, and further optimizing the ratios of neutral monomers (Ia, Ib) and ionized monomers (Ic) within their specified ranges. This multi-parameter optimization ensures that sufficient crosslinking density is achieved for adequate shell strength while maintaining the pH-independent properties through the balanced composition of neutral and ionized monomers.
Solution Approach 2:
The patent uses composite materials by combining polyethylenically unsaturated monomer (II) which provides crosslinking and strength, with neutral monomers (Ia, Ib) and ionized monomers (Ic) which provide pH stability. The synergistic interaction between these different functional monomer components creates a composite polymer structure that simultaneously achieves both shell strength and pH-independent properties, resolving the contradiction between these two requirements.
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 microcapsule achieves reduced fragrance leakage and maintains olfactive properties over time, even in extreme pH conditions, ensuring consistent performance in diverse consumer products.
Implementation Method 1
a process for the manufacture of that microcapsule which is a free radical polymerization process
Data Source
AI summary
The present disclosure discloses a novel microcapsule which is endowed for example with reduced leakage of encapsulated materials. The microcapsule contains one or more fragrances and is suitable for inclusion in non-edible consumer goods products, laundry products, personal care products and cosmetic products. The microcapsule can be obtained in an economic and efficient manner by polymerizing an emulsion so that emulsion droplets are encapsulated into a subsequently cured polymeric shell.