Three-Component Acrylic Binder for Transparent Wood Primer
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Solution Overview
Problem
There is a need for a coating composition that combines low VOC, fast drying, good end-hardness, and early sandability without the use of inorganic fillers, suitable for use as a transparent or translucent wood primer.
Innovation Solution
An aqueous binder composition comprising three different dispersed polymers: an acrylic polymer with a glass transition temperature (Tg) between 80 and 120°C, an acrylic polymer with a Tg between 40 and 60°C, and a polyurethane modified acrylic polymer, which provides a fast-drying coating with high end-hardness and early sandability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic fillers are used to improve coating properties like tensile strength, hardness, and sandability, then the coating achieves good end-hardness and sandability, but the coating loses transparency and experiences high viscosity build-up
Solution Approach 1:
The patent changes the chemical composition parameters by using specific acrylic polymers with controlled glass transition temperatures (80-120°C and 40-60°C) and polyurethane modified acrylic polymers instead of inorganic fillers. This parameter change achieves the desired hardness and sandability while maintaining transparency, as the organic polymers do not cause the opacity and viscosity issues associated with inorganic fillers like CaCO3, clay, or quartz
Solution Approach 2:
The patent creates a composite binder system combining multiple acrylic polymers with different Tg values and polyurethane modified acrylic polymers. This composite organic material system provides the mechanical properties (hardness, sandability) traditionally achieved through inorganic fillers, while maintaining the transparency and low viscosity characteristics of organic polymer-based coatings
2Object-generated harmful factors
If water-based coating compositions are used to limit VOC content, then the coating achieves low VOC emissions, but the coating may have slower drying speed and reduced end-hardness
Solution Approach 1:
The patent changes the binder polymer parameters by selecting acrylic polymers with specific glass transition temperatures (80-120°C for high Tg component, 40-60°C for low Tg component) and incorporating polyurethane modified acrylic polymers. These parameter changes enable the water-based coating to achieve fast drying and high end-hardness while maintaining low VOC content, as the polymer composition itself provides the drying and hardness characteristics without requiring inorganic fillers
3Quantity of substance
If inorganic fillers are added to increase solids volume and improve covering capacity, then the coating achieves high solids volume and better filling, but the coating experiences high viscosity build-up and sedimentation
Solution Approach 1:
The patent changes the composition parameters by using organic polymer binders (acrylic and polyurethane modified acrylic) instead of inorganic fillers to achieve high solids volume. The polymer-based system maintains coating stability with minimal viscosity build-up and no sedimentation, as the polymers are dissolved or dispersed at the molecular level rather than forming separate inorganic particles that settle
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 composition achieves high end-hardness and early sandability without inorganic fillers, making it suitable for transparent or translucent wood coatings, with a high solids volume content and quick drying properties.
Implementation Method 1
an acrylic polymer with a Tg between 80 and 120° C.
Implementation Method 2
an acrylic polymer with a Tg between 40 and 60° C.
Implementation Method 3
a polyurethane modified acrylic polymer
Data Source
AI summary
The invention relates to an aqueous binder composition comprising three different dispersed polymers: an acrylic polymer a. with a Tg between 80 and 120° C.; an acrylic polymer b. with a Tg between 40 and 60° C.; and a polyurethane modified acrylic polymer c. The binder composition can be used in a coating composition, especially in a primer composition.