Multi-Stage Polymer Grind Additive for Paint Scrub Resistance
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Solution Overview
Problem
Current paint formulations using Hydrophobically-modified Alkali Soluble Emulsion (HASE) and hydrophobic dispersants face compatibility issues, leading to compromised scrub resistance and washability, while existing solutions either increase paint film hydrophilicity or cause processing problems.
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 developed to enhance compatibility and performance, allowing for improved washability and opacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HASE is added in the letdown stage to reach target viscosity, then viscosity is improved, but scrub resistance (washability) deteriorates due to increased hydrophilicity
Solution Approach 1:
The invention creates a composite polymer structure by grafting hydrophobic side chains onto a HASE backbone. This composite structure combines the viscosity-providing capability of HASE with the hydrophobicity of side chains, achieving both high viscosity and improved scrub resistance simultaneously.
Solution Approach 2:
The polymer structure exhibits local quality differentiation: the backbone provides hydrophilic character for water solubility and viscosity, while the grafted side chains provide localized hydrophobic regions that enhance scrub resistance. This spatial distribution of properties resolves the contradiction between viscosity and washability.
2Reliability
If hydrophobic copolymer dispersant is used to replace polyacid dispersant to make paint film more hydrophobic, then scrub resistance is improved, but compatibility with HASE deteriorates causing grid formation
Solution Approach 1:
The invention merges the characteristics of HASE (hydrophilic backbone for compatibility) and hydrophobic dispersants (side chains for scrub resistance) into a single unified polymer structure. This eliminates the compatibility issues between separate HASE and hydrophobic dispersant components while maintaining both functions.
Solution Approach 2:
The grafted copolymer creates a composite material where the HASE backbone ensures compatibility and solubility, while the hydrophobic side chains provide dispersant functionality and scrub resistance, resolving the contradiction between compatibility and performance.
3Stability of the object's composition
If polyacid dispersant is used in the grinding stage, then dispersion is achieved, but scrub resistance deteriorates due to hydrophilic paint film
Solution Approach 1:
The invention changes the chemical parameters of the dispersant by introducing hydrophobic side chains onto the polymer backbone. This parameter modification transforms a purely hydrophilic dispersant into an amphiphilic structure that maintains dispersion capability while adding hydrophobic character for improved scrub resistance.
Data Source
AI summary
Provided are a multi-stage polymer comprising a first stage and second stage polymer as a grinding additive and the preparation process thereof. The first stage polymer is prepared from a mixture of : a) 0.1-50 wt% of a nonionic macro-monomer; b) 30-70 wt% an α, β - ethylenicallyβ unsaturated carboxylic acid monomer; and c) 30-70 wt% α, β - ethylenically unsaturated nonionic monomer. The polymerization units of the second stage polymer comprise: e) 10-70 wt% of a α, β - ethylenically unsaturated carboxylic acid monomer; and f) 30-90 wt% nonionic α, β - ethylenically unsaturated monomer.