Aqueous Polymer Latex Binder for Waterborne Coatings
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Solution Overview
Problem
Existing waterborne coating compositions with titanium dioxide (TiO2) pigments face challenges in achieving optimal hiding and opacifying efficacy due to agglomeration of TiO2 particles, leading to reduced light scattering efficiency and stability issues, often requiring expensive phosphorous-containing monomers or complex dispersant synthesis.
Innovation Solution
An aqueous polymer latex is used as a binder or co-binder in waterborne coating compositions, obtained by radical emulsion polymerization of a monomer composition comprising tert-butyl acrylate or methacrylate, n-butyl acrylate, mono-ethylenically unsaturated carboxylic acid, and acrylamide derivatives, promoting homogeneous TiO2 distribution and interaction without the need for expensive phosphorous-containing monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If higher levels of TiO2 are used to achieve desired hiding and whiteness, then hiding power is improved, but light scattering efficiency is reduced due to particle crowding and agglomeration
Solution Approach 1:
The patent introduces a polymer latex binder as an intermediary substance that mediates between TiO2 pigment particles and the coating matrix. This binder promotes homogeneous dispersion of TiO2 particles, preventing agglomeration and maintaining optimal spacing for light scattering even at higher pigment loadings. The binder acts as a spacer and stabilizing agent that prevents direct particle-particle contact and agglomeration.
Solution Approach 2:
The patent changes the chemical and physical parameters of the binder system by using a specific polymer latex composition with controlled molecular weight, glass transition temperature, and functional groups. These parameter changes enable the binder to optimize TiO2 particle spacing and interaction, maintaining light scattering efficiency while accommodating higher pigment concentrations.
2Reliability
If phosphorous-containing monomers are used to improve TiO2 particle distribution, then hiding power is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive phosphorous-containing monomers with cheaper alternative monomers that achieve the same functional effect. The invention uses conventional monomers (acrylic acid, methacrylic acid, carboxylic acid derivatives) that are less costly than phosphorous-containing monomers while still providing effective TiO2 particle stabilization and homogeneous distribution.
Solution Approach 2:
The patent changes the chemical composition parameters of the binder by substituting phosphorous-containing monomers with alternative carboxylic acid-based monomers. This parameter substitution maintains the essential function of TiO2 particle stabilization and distribution while significantly reducing material cost. The alternative monomers provide sufficient binding and dispersing capabilities without requiring expensive phosphorous compounds.
3Reliability
If complex dispersant synthesis is used to prevent TiO2 agglomeration, then particle distribution is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex dispersant synthesis step from the manufacturing process. Instead of using complex, multi-step synthesized dispersants, the invention employs a simpler polymer latex binder that is directly formed during emulsion polymerization. This extraction of the complex synthesis process simplifies manufacturing while maintaining effective TiO2 particle distribution and preventing agglomeration.
Solution Approach 2:
The patent creates a universal polymer latex binder that performs multiple functions simultaneously: it acts as the coating matrix, provides TiO2 particle stabilization, ensures homogeneous distribution, and maintains light scattering efficiency. This multi-functional approach eliminates the need for separate complex dispersant systems, reducing overall process complexity while achieving the desired particle distribution.
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 solution achieves improved hiding and opacifying efficacy while maintaining coating stability and preventing grit formation, providing excellent opacity to the coated surface without the use of costly phosphorous-containing monomers.
Implementation Method 1
promotes the interaction between binder and pigments
Implementation Method 2
promotes the homogeneity of the TiO2 particle distribution
Implementation Method 3
The opacifying capacity of a coating is maximized when the light scattering capability of the opacifying pigment, namely TiO2, is maximized
Data Source
AI summary
The presently claimed invention relates to use of an aqueous polymer latex as a binder or co-binder in a waterborne coating composition, wherein the aqueous polymer latex is obtained by polymerizing a monomer composition M, comprising at least one tert-butyl acrylate and/or tertbutyl methacrylate monomer, by radical emulsion polymerization.