Multi-stage Polymer Grinding Additive for Paint Viscosity
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Solution Overview
Problem
Current paint formulations using Hydroxyethyl Cellulose (HEC) and polyacid dispersants face challenges in achieving long-term viscosity stability and pigment dispersion, particularly when replaced by Hydrophobically-modified Alkali Soluble Emulsion (HASE) in the letdown stage, which compromises scrub resistance and dispersion efficiency.
Innovation Solution
A multi-stage polymer comprising a first stage HASE polymer and a second stage hydrophobic polymer dispersant, with specific monomer compositions and molecular weight ranges, is used as a grinding additive to enhance pigment dispersion and viscosity stability, formulated through sequential emulsion polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HASE is added in the letdown stage to replace HEC for cost saving and better flow/leveling, then flow and leveling are improved, but scrub resistance (washability) is significantly reduced
Solution Approach 1:
The patent combines HASE polymer and hydrophobic copolymer dispersant into a single multi-stage polymer particle system. The HASE polymer (first stage) provides flow and leveling properties, while the hydrophobic copolymer dispersant (second stage) maintains scrub resistance through its hydrophobic character. This merging allows both contradictory requirements to be satisfied simultaneously within one integrated additive system.
Solution Approach 2:
The multi-stage polymer particle is a composite structure consisting of HASE polymer matrix with incorporated hydrophobic copolymer dispersant. This composite material structure allows the system to exhibit both the hydrophilic properties of HASE (for flow/leveling) and the hydrophobic properties of the dispersant (for scrub resistance), resolving the contradiction between these opposing requirements.
2Reliability
If hydrophobic copolymer dispersant is used to replace polyacid dispersant to make the paint film more hydrophobic, then scrub resistance is improved, but dispersion of pigment and long term viscosity stability are insufficient
Solution Approach 1:
The patent merges the thickening function of HASE polymer with the dispersant function of hydrophobic copolymer into a single multi-stage polymer particle. The HASE component provides viscosity stability and flow properties, while the hydrophobic copolymer component ensures effective pigment dispersion and maintains scrub resistance. This combination resolves the contradiction between hydrophobicity and dispersion stability.
3Stability of the object's composition
If HEC and polyacid dispersant are used in the grinding stage to deliver dispersion and viscosity, then pigment dispersion and viscosity are achieved, but cost is higher and flow/leveling are inferior compared to HASE replacement
Solution Approach 1:
The multi-stage polymer particle serves multiple functions simultaneously: it acts as a thickener (providing viscosity), a dispersant (ensuring pigment dispersion), and a flow/leveling agent. This multi-functionality replaces the need for separate HEC and polyacid dispersant additives, reducing material costs while maintaining or improving performance characteristics.
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 multi-stage polymer effectively improves pigment dispersion and long-term viscosity stability, maintaining paint film properties and scrub resistance, even after heat-age storage, compared to conventional formulations.
Implementation Method 1
formulated through sequential emulsion polymerization
Implementation Method 2
a multi-stage polymer comprising a first stage HASE polymer and a second stage hydrophobic polymer dispersant
Data Source
Figure 1
AI summary
This invention generally relates to a multi-stage polymer suitable for a grinding additive, a method for producing the multi-stage polymer, a composition and a paint composition comprising the multi-stage polymer and a use of the multi-stage polymer for a grinding additive of a paint composition.