Alkyl-Modified Copolymer Thickener for Electrolyte Stability
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Solution Overview
Problem
Conventional copolymers of (meth)acrylic acid and alkyl (meth)acrylate ester exhibit poor water solubility and significant viscosity changes in the presence of electrolytes, making it difficult to maintain consistent viscosity and transparency in cosmetic applications.
Innovation Solution
A copolymer comprising 100 parts by mass of (meth)acrylic acid, 1.5 to 4.5 parts by mass of alkyl (meth)acrylate ester with 18 to 24 carbon atoms, and 0 to 0.1 parts by mass of a compound with two or more ethylenically unsaturated groups, along with 1.5 to 4.5 parts by mass of a nonionic surfactant, which is copolymerized to produce a neutralized viscous liquid with improved dispersibility and stability in the presence of electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copolymers of (meth)acrylic acid and alkyl (meth)acrylate ester are used, then they can provide thickening function in cosmetics, but they exhibit poor water solubility and significant viscosity changes in the presence of electrolytes
Solution Approach 1:
The patent creates a composite polymer structure by copolymerizing three components: (meth)acrylic acid (provides carboxyl groups for thickening), alkyl (meth)acrylate ester with 18-24 carbon atoms (improves water solubility and prevents precipitation), and a compound with two or more ethylenically unsaturated groups (enhances structural stability). This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both viscosity stability and water solubility.
Solution Approach 2:
The patent optimizes specific compositional parameters: the alkyl group is restricted to 18-24 carbon atoms (narrowing the range from conventional 8-30 carbons), the electrolyte concentration is controlled at 0.1-10 mass%, and the polymer concentration is maintained at 0.1-1 mass%. These parameter changes ensure the copolymer maintains stable viscosity and solubility across varying conditions.
2Strength
If the copolymer concentration is increased to maintain viscosity, then thickening effect is improved, but light transmittance decreases and the liquid becomes less transparent
Solution Approach 1:
The patent optimizes the polymer concentration parameter to 0.1-1 mass%, which is a relatively low concentration range. Within this optimized parameter range, the copolymer achieves effective thickening while maintaining high light transmittance and transparency, resolving the contradiction between thickening effect and transparency.
3Adaptability or versatility
If electrolyte concentration is increased to improve product formulation, then functional ingredients can be added, but copolymer precipitation occurs and viscosity decreases
Solution Approach 1:
The copolymer's composite structure, particularly the inclusion of alkyl (meth)acrylate ester with 18-24 carbon atoms, provides electrolyte resistance that prevents precipitation. This allows the formulation to maintain flexibility for adding functional ingredients while preserving viscosity stability even at electrolyte concentrations of 0.1-10 mass%.
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 copolymer produces a neutralized viscous liquid with excellent water dispersibility, stable viscosity, and high transparency, even in the presence of electrolytes, suitable for use as a thickener in cosmetics.
Implementation Method 1
reacting a specified amount of an olefinic unsaturated carboxylic acid monomer, a specified amount of an alkyl (meth)acrylate ester, and a crosslinking agent
Implementation Method 2
1.5 to 4.5 parts by mass of a nonionic surfactant
Data Source
AI summary
Provided is an alkyl-modified carboxyl group-containing copolymer with which a neutralized viscous liquid can be prepared which has excellent dispersibility in water, has a viscosity that does not change greatly regardless of addition of an electrolyte, and has high transparency in the presence of an electrolyte. This alkyl-modified carboxyl group-containing copolymer contains: 100 parts by mass of a (meth)acrylic acid; 1.5-4.5 parts by mass of a (meth)acrylic acid alkyl ester, in which an alkyl group has 18-24 carbon atoms; and 0-0.1 parts by mass of a compound having two or more ethylenically unsaturated groups, wherein the copolymer contains 1.5-4.5 parts by mass of a nonionic surfactant.