Aqueous Polymer Dispersion for High Gloss Coatings
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Solution Overview
Problem
Developing aqueous polymeric acrylic/alkyd hybrid emulsions that enhance compatibility between immiscible systems while meeting regulatory requirements for low VOC and cobalt-free coatings, and reducing the negative impact of high temperature processes on cost and carbon footprint.
Innovation Solution
A stepwise emulsion polymerization process producing a heterogeneous polymer dispersion with specific monomer compositions and chain transfer agents to create polymer phases with controlled glass transition temperatures, enhancing compatibility with alkyd resins and allowing for the production of decorative coatings with high gloss and low haze without drying agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stepwise emulsion polymerization process with chain transfer agents is used to create polymer phases with controlled glass transition temperatures, then compatibility with alkyd resins is enhanced and coating quality (gloss, haze) is improved, but the process complexity and manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the polymerization process into multiple stages (first stage polymerization, second stage polymerization) with different monomer compositions. This creates a heterogeneous polymer dispersion with distinct polymer phases having different glass transition temperatures, which enhances compatibility with alkyd resins while maintaining coating quality.
Solution Approach 2:
The patent employs parameter changes by systematically varying the composition of monomer mixes in different polymerization stages and using chain transfer agents to control the glass transition temperatures of resulting polymer phases. This allows precise tuning of polymer properties to achieve optimal compatibility with alkyd resins and desired coating characteristics.
2Stability of the object's composition
If high temperature processes are used to incorporate alkyd resin into the polymer dispersion, then the resin is properly integrated, but the carbon footprint and manufacturing costs increase
Solution Approach 1:
The patent changes the temperature parameter by conducting polymerization at controlled temperatures (e.g., 50-80°C) rather than high temperatures. This allows proper integration of alkyd resin through the stepwise polymerization process while significantly reducing energy consumption and carbon footprint compared to conventional high-temperature methods.
3Productivity
If drying agents are used in the coating formulation, then the coating dries properly, but the environmental compliance issues and regulatory restrictions increase
Solution Approach 1:
The patent applies self-service by formulating the coating with controlled glass transition temperatures through stepwise polymerization, enabling the coating to dry and cure through its own inherent properties without requiring external drying agents. This eliminates the need for cobalt driers and other regulated substances while maintaining proper drying performance.
4Ease of operation
If the glass transition temperature of the polymer is lowered to improve flow and application properties, then the coating applies smoothly, but the blocking resistance and early curing performance decrease
Solution Approach 1:
The patent segments the polymer system into multiple phases with different glass transition temperatures. The first polymer phase has a lower Tg for good flow and application properties, while the second polymer phase has a higher Tg to provide blocking resistance and early curing performance. This segmented structure allows both contradictory requirements to be satisfied simultaneously.
Solution Approach 2:
The patent creates a composite polymer system combining different polymer phases with complementary properties. The heterogeneous dispersion of polymer particles with varying Tg values allows the coating to exhibit both good application properties (from lower Tg phases) and adequate blocking resistance (from higher Tg phases).
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 process results in an aqueous polymer composition that achieves enhanced compatibility with alkyd resins, producing coatings with high gloss and improved blocking resistance without the use of drying agents, while reducing environmental impact and manufacturing burdens.
Implementation Method 1
the first polymerization stage is conducted in the presence of 0.05 to 3 wt%, preferably 0.5 to 2 wt%, based on the total weight of monomers in the first monomer composition, of a chain transfer agent (C) to produce a first polymer phase having a Tg less than or equal to 20°C
Implementation Method 2
a heterogeneous polymer dispersion prepared by a stepwise emulsion polymerization process comprising polymerizing in a first stage a first monomer composition
Implementation Method 3
The dispersion is obtained by free radical emulsion polymerization of at least one α, β,-ethylenically unsaturated monomer (M) and optionally at least one further monomer (M1)
Implementation Method 4
a heterogeneous polymer dispersion prepared by a stepwise emulsion polymerization process comprising polymerizing in a first stage a first monomer composition... and polymerizing in a second stage, and in the presence of the first polymer phase, a second monomer composition
Data Source
AI summary
An aqueous polymer composition is described comprising a homogeneous acrylic polymer dispersion produced by emulsion polymerization of a monomer mixture comprising: (A) from 85 to 99.9 wt%, based on the total weight of monomers in the mixture, of one or more main monomers selected from C1-C12-alkyl esters of acrylic acid or C5-C12-alkyl esters of methacrylic acid, styrene, and vinyl toluene in such a ratio as to produce a polymer having a Tg in the range of -20 to +65 °C; and (B) from 0.1 to 5 wt%, based on the total weight of monomers in the mixture, of at least one stabilising monomer selected from ethylenically unsaturated monocarboxylic acids or amides thereof, ethylenically unsaturated dicarboxylic acids or anhydrides or amides thereof, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphoric acids, and ethylenically unsaturated phosphonic acids. The emulsion polymerization is conducted in the presence of 0.05 to 3 wt%, based on the total weight of monomers in the monomer mixture, of a chain transfer agent (C). Also described are an aqueous polymer composition comprising a heterogeneous acrylic polymer dispersion and an aqueous polymeric acrylic/alkyd hybrid dispersion useful in the formulation of high gloss paints.