Copolymer Thickener Reduces Laundry Graying in Liquid Detergents
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Solution Overview
Problem
Existing thickeners for liquid textile detergents often cause graying of laundry due to light reflectance issues and fail to provide high thickening effect with simultaneous high shear thinning and transparency.
Innovation Solution
A copolymer is used as a thickener, comprising at least 15% ethylenically unsaturated carboxylic acid, 15% to 85% C4-C8 alkyl acrylate, less than 5% methyl methacrylate, and a nonionic ethylenically unsaturated surfactant monomer, which is produced through emulsion polymerization with specific initiators and conditions to achieve high transparency and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thickeners are used to increase viscosity and provide high thickening effect, then the detergent achieves high viscosity at rest and shear thinning, but graying of laundry occurs due to light reflectance issues
Solution Approach 1:
The patent changes the chemical composition parameters of the thickener by specifying exact proportions of carboxylic acid units (15-50%), C4-C8 alkyl acrylate units (20-80%), and methyl methacrylate units (0.1-10%). This precise parameter control optimizes the thickening effect while minimizing light reflectance issues that cause graying, resolving the contradiction between thickening performance and laundry appearance.
Solution Approach 2:
The patent uses a composite polymer structure combining multiple monomer units (carboxylic acid, C4-C8 alkyl acrylate, and methyl methacrylate) in specific ratios. This composite approach allows the thickener to achieve high viscosity and shear thinning properties while controlling light reflectance, thereby preventing graying of laundry during the wash process.
2Strength
If high proportion of C1-C2 alkyl methacrylate units are used in thickeners, then thickening effect is enhanced, but light reflectance of washed laundry deteriorates
Solution Approach 1:
The patent optimizes the parameter of methyl methacrylate unit content to a specific range (0.1-10% by weight), balancing the thickening effect with light reflectance properties. This parameter optimization ensures sufficient viscosity enhancement while preventing excessive light absorption that would reduce laundry brightness and cause graying.
3Illumination intensity
If transparent viscous liquid detergent is formulated, then consumer appeal increases, but clouding occurs when thickeners are incorporated into surfactant-containing formulations
Solution Approach 1:
The patent controls the chemical composition parameters of the thickener, specifically the ratio of hydrophilic carboxylic acid units to hydrophobic C4-C8 alkyl acrylate units, to ensure compatibility with surfactant formulations. This parameter control maintains transparency and prevents clouding while preserving the desired viscous texture and thickening effect in the final detergent product.
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 copolymer significantly reduces laundry graying, maintains high thickening effect, and ensures high transparency and viscosity, even under shear forces, while minimizing light reflectance issues.
Implementation Method 1
Associative thickeners are water-soluble polymers and have surfactant-like hydrophobic components which are able to associate, i.e. interact, with themselves as well as with other hydrophobic substances in a hydrophilic, especially aqueous medium. The resulting associative network causes the medium to thicken or gel.
Implementation Method 2
thickeners are desirable that give the thickened medium a very high viscosity when at rest and a low viscosity when exposed to high shear forces
Data Source
AI summary
The invention relates to copolymers which contain a) at least 15% by weight units of an ethylenically unsaturated carboxylic acid, b) at least 15% by weight units of a C4-C8-alkylacrylats, c) less than 5% by weight units of methyl methacrylate, and are used as thickeners in liquid textile detergents. The copolymers can additionally contain units of a non-ionic ethylenically unsaturated surfactant monomer that are incorporated by polymerization. The thickeners are characterized by high thickening action, high shear thinning and low graying of the laundry after the washing process.