Epoxy-Functional Silane Modification of Aqueous Polymer Latex at 60°C
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Solution Overview
Problem
Existing aqueous polymer latex-based coatings lack sufficient chemical resistance, especially against water and household chemicals, and require improvements in durability and storage stability, particularly for use in industrial varnishes for furniture and doors.
Innovation Solution
Modify carboxyl group-bearing polymer latexes by adding an epoxy functional silane compound at elevated temperatures during polymerization, forming stable siloxane bonds and enhancing adhesion and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy functional silane compound is added at ambient temperature to carboxyl-functionalized polymer latex, then adhesion to mineral substrates is enhanced, but chemical resistance against water and household chemicals deteriorates
Solution Approach 1:
The patent changes the temperature parameter from ambient to elevated (60-90°C) during the mixing of epoxy functional silane with carboxyl-functionalized polymer latex. This parameter change transforms the reaction mechanism, enabling simultaneous achievement of adhesion enhancement and chemical resistance that cannot be obtained at ambient temperature.
Solution Approach 2:
The patent creates a composite modified polymer latex by combining carboxyl-functionalized polymer latex with epoxy functional silane compound at elevated temperatures. The resulting composite material exhibits synergistic properties where the silane-modified polymer particles provide both adhesion enhancement and chemical resistance.
2Reliability
If epoxy functional silane is added to improve chemical resistance, then storage stability deteriorates due to coagulum formation and viscosity increase
Solution Approach 1:
The patent applies parameter changes by conducting the silane modification at elevated temperatures (60-90°C) rather than ambient temperature. This temperature parameter change prevents premature coagulum formation and viscosity increase, maintaining storage stability while achieving chemical resistance.
Solution Approach 2:
The patent performs preliminary action by pre-heating the carboxyl-functionalized polymer latex to elevated temperature before adding the epoxy functional silane compound. This preliminary heating prepares the system for optimal silane reaction, preventing subsequent storage stability issues.
3Ease of manufacture
If silane modification is performed at ambient temperature, then process simplicity is maintained, but coating durability deteriorates
Solution Approach 1:
The patent changes the temperature parameter from ambient to elevated (60-90°C) to achieve proper silane reaction kinetics. This parameter change ensures complete reaction between silane and carboxyl groups, resulting in durable coatings with enhanced chemical resistance and adhesion.
Solution Approach 2:
The patent employs periodic action by heating the mixture to elevated temperature for a specific reaction period, then cooling and neutralizing. This controlled periodic process ensures complete reaction while managing the complexity of the manufacturing process.
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 modified polymer latexes exhibit improved chemical resistance, durability, and storage stability, making them suitable as binders for coatings that resist water, household chemicals, and environmental factors.
Implementation Method 1
forming stable siloxane bonds and enhancing adhesion and mechanical strength
Implementation Method 2
adding at least one silane compound of the formula (I) at a temperature of at least 60°C
Data Source
AI summary
The present invention relates to a process for modifying an aqueous polymer latex of polymer particles that bear carboxyl groups comprising the mixing of the aqueous polymer latex with at least one silane compound of formula (1) at a temperature of at least 60°C: (RO)3-nR1 nSiR2X (1) wherein R is C1-C10-alkyl, C3-C10-cycloalkyl, C6-C10-aryl, C1-C10-alkoxy-C1-C10-alkyl, C2-C10-alkenyl, C1-C4-alkyl-C6-C10-aryl or C6-C10-aryl-C1-C4-alkyl, R1 is C1-C10-alkyl, C3-C10-cycloalkyl, C6-C10-aryl, C2-C10-alkenyl, C1-C4-alkyl-C6-C10-aryl or C6-C10-aryl-C1-C4-alkyl, R2 is a covalent chemical bond or a C1-C20-alkylene, in which non-adjacent methylene units can be replaced by O-groups, n is 0, 1, 2 or 3, and X is a radical having 3 to 10 carbon atoms and bearing an oxirane group. The present invention also relates to modified aqueous polymer latexes obtainable by such process and to the use of these polymer latexes as binders or co-binders for industrial varnishes.