Polyurethane-Acrylic Copolymer Pigment Paste
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Solution Overview
Problem
Current pigment pastes in the paint industry face challenges in achieving optimal pigment dispersion and application technology properties, particularly in aqueous basecoats, due to mismatched polymer binders, leading to issues like pinholes and reduced formulation freedom.
Innovation Solution
A pigment paste with a copolymer dispersion, specifically a polyurethane-poly(acrylic ester) copolymer, is developed, where the copolymer is produced by polymerizing olefinically unsaturated monomers in the presence of a polyurethane using a water-soluble initiator, maintaining a controlled monomer concentration and ratio, allowing the copolymer to serve as both a paste binder and main binder in aqueous basecoats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a specific polymer is used as paste binder to achieve optimal pigment dispersion, then pigment dispersion quality is improved, but formulation freedom is reduced and manufacturing complexity increases
Solution Approach 1:
The copolymer is designed to perform multiple functions simultaneously: it serves as both the paste binder for optimal pigment dispersion and the main binder in the final coating composition. This multi-functionality eliminates the need for separate paste binder and main binder components, thereby maintaining formulation freedom while achieving high pigment dispersion quality.
Solution Approach 2:
The invention merges the functions of paste binder and main binder into a single copolymer component. By combining these two previously separate roles into one universal binder, the patent resolves the contradiction between achieving optimal pigment dispersion (which requires specific paste binder properties) and maintaining formulation freedom (which is reduced when using dedicated paste binders).
2Adaptability or versatility
If a polymer corresponding to the main binder is used as paste binder to maintain formulation freedom, then formulation freedom is preserved, but application technology properties and stability against pinholes deteriorate
Solution Approach 1:
The copolymer's composition parameters are precisely controlled, with the proportion of polyurethane units ranging from 5-50% and acrylic ester units from 50-95%. By adjusting these compositional parameters, the patent achieves both good pigment dispersion properties (needed for reliability against pinholes) and compatibility with the main binder system (preserving formulation freedom).
Solution Approach 2:
The copolymer itself is a composite material combining polyurethane and acrylic ester segments in controlled ratios. This composite structure allows the single binder to exhibit both the pigment-dispersing properties of polyurethane and the film-forming and stability properties of acrylic esters, thereby achieving reliability against pinholes while maintaining formulation freedom.
3Manufacturing precision
If a different polymer is used as paste binder than the main binder, then optimal pigment dispersion is achieved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The copolymer serves as a universal binder that replaces both the traditional paste binder and main binder roles. This eliminates the need for separate polymer selection and compatibility testing processes, thereby reducing manufacturing process complexity while maintaining optimal pigment dispersion through the copolymer's tailored composition.
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
This approach enhances the application properties of the paint finish, including improved stability against pinholes and increased formulation freedom, allowing for better visual appearance and performance in multi-layer coatings.
Implementation Method 1
polymerizing a mixture of olefinically unsaturated monomers in the presence of the polyurethane from (i)
Data Source
AI summary
The invention relates to a pigment paste containing at least one aqueous dispersion that contains at least one mixed polymer, the mixed polymer being producible by i) providing an aqueous dispersion of at least one polyurethane, and then ii) polymerizing a mixture of olefinically unsaturated monomers in the presence of the polyurethane from step i), wherein a) a water-soluble initiator is used, b) the olefinically unsaturated monomers are added in a dosed manner such that the concentration in the reaction solution during the entire reaction time does not exceed 6.0 wt % in relation to the total amount of olefinically unsaturated monomers used for the polymerization process, and c) the mixture of the olefinically unsaturated monomers contains at least one polyolefinically unsaturated monomer. The pigment paste further contains a pigment, the weight ratio of the pigment to the the mixed polymer being at least 1.5. The invention also relates to the use of the mixed polymer for suspending pigments.