Fluorine-Containing Polymer Aqueous Dispersion for Weather-Resistant Coatings
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Solution Overview
Problem
Existing aqueous fluororesin compositions for weather-resistant coatings lack optimal balance of weather resistance, hardness, and dispersion stability, particularly in salt water environments.
Innovation Solution
An aqueous dispersion containing a fluorine-containing polymer with specific monomer units, including fluorine-containing, carboxy group-containing, and hydroxy group-containing monomers, optimized in molecular composition and structure to enhance weather resistance, hardness, and dispersion stability, along with a surfactant for improved stability and film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous fluororesin compositions are used, then weather resistance is improved, but hardness and dispersion stability are insufficient
Solution Approach 1:
The patent uses a composite fluorine-containing polymer comprising multiple polymerized units (fluorine-containing, carboxy group-containing, and hydroxy group-containing monomers) to achieve both weather resistance and hardness. The specific composition ratios (carboxy group-containing: 4.0-14.0 mol %, hydroxy group-containing: 14.0-35.0 mol %) create a synergistic effect where each component contributes specific properties to the final coating film.
Solution Approach 2:
The patent optimizes the molecular composition parameters of the fluorine-containing polymer by controlling the amounts of different polymerized units within specific ranges. This parameter optimization ensures that the coating film achieves both excellent weather resistance and hardness, resolving the contradiction between these two properties.
2Reliability
If conventional aqueous fluororesin compositions are used, then weather resistance is improved, but dispersion stability is insufficient
Solution Approach 1:
The patent employs a composite polymer structure where the hydroxy group-containing polymerized unit (14.0-35.0 mol %) provides hydrophilic characteristics that enhance dispersion stability in aqueous environments, while the fluorine-containing unit (20-60 mol %) provides weather resistance. This composite approach allows simultaneous achievement of both properties.
Solution Approach 2:
By controlling the ratio of hydroxy group-containing to fluorine-containing polymerized units within specific ranges, the patent optimizes both dispersion stability and weather resistance. The specific parameter ranges ensure that the polymer maintains stability in aqueous dispersions while providing the required weather resistance properties.
3Reliability
If fluorine-containing polymer with high fluorine content is used, then weather resistance is improved, but dispersion stability deteriorates
Solution Approach 1:
The patent optimizes the parameter of fluorine content by controlling it within a specific range (20-60 mol % of total polymerized units). This optimized parameter range ensures that the polymer provides sufficient weather resistance while maintaining dispersion stability in aqueous environments, preventing the deterioration that would occur with excessive fluorine content.
Solution Approach 2:
The patent creates a composite polymer system where the hydroxy group-containing unit (14.0-35.0 mol %) acts as a stabilizing component that prevents aggregation and maintains dispersion stability, while the fluorine-containing unit (20-60 mol %) provides weather resistance. This composite structure resolves the contradiction between fluorine content and dispersion stability.
Data Source
AI summary
The disclosure provides an aqueous dispersion that can provide a film having excellent weather resistance and excellent hardness and that has excellent dispersion stability. The aqueous dispersion contains a fluorine-containing polymer that contains: a polymerized unit (a) based on a fluorine-containing monomer; a polymerized unit (b) based on a carboxy group-containing monomer; and a polymerized unit (c) based on a hydroxy group-containing monomer. The polymerized unit (b) is contained in an amount of 4.0 to 14.0 mol % of all polymerized units and the polymerized unit (c) is contained in an amount of 14.0 to 35.0 mol % of all polymerized units.