Aqueous Coating Composition for Multilayer Film Chipping Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aqueous 3-coat, 1-bake systems using water-based intercoat and base coating materials face issues with layer mixing, reduced smoothness, and impaired water resistance and chipping resistance in multilayer coating films.
Innovation Solution
An aqueous coating composition comprising an acryl-modified polyester resin with a polyoxyalkylene chain, a crosslinking agent, and an epoxy phosphoric acid ester compound, where the acryl-modified polyester resin has a weight-average molecular weight of 400 or greater and a proportion of compounds with 6 or more carbon atoms is 50 mass% or greater, and the epoxy phosphoric acid ester compound is present in a specific mass ratio, enhancing dispersion stability and curing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous intercoat material and aqueous base coating material are used in a 3-coat, 1-bake system, then environmental pollution is minimized, but layer mixing occurs and smoothness deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the intercoat material by incorporating polyester resin with specific molecular weight (10,000-50,000) and controlled water solubility. This parameter change allows the intercoat film to resist dissolution by aqueous base coating materials while maintaining environmental benefits of water-based systems.
Solution Approach 2:
The patent creates a composite intercoat material system combining polyester resin, acrylic resin, and specific curing agents. This composite formulation provides both water resistance to prevent layer mixing and smoothness, while the base coating uses water-soluble acrylic resin for environmental compatibility.
2Object-affected harmful factors
If water-soluble or water-dispersible film-forming resins are used in aqueous coating materials, then environmental pollution is minimized, but water resistance and chipping resistance deteriorate
Solution Approach 1:
The patent changes the water resistance parameter by selecting polyester resin with specific molecular weight range (10,000-50,000) and controlling the water solubility parameter through resin composition. This allows the intercoat film to maintain water resistance even in an aqueous coating system.
Solution Approach 2:
The patent introduces a curing agent as an intermediary that creates crosslinked structures in the intercoat film. This crosslinking mechanism provides water resistance and chipping resistance without requiring organic solvents, bridging the gap between environmental compatibility and performance requirements.
3Manufacturing precision
If polyester resin with benzene ring and cyclohexane ring is used in aqueous intercoat material, then smoothness and chipping resistance are improved, but storage stability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of polyester resin to the range of 10,000-50,000, which balances the smoothness provided by aromatic and alicyclic rings with storage stability. This parameter control prevents excessive reactivity that would cause storage issues while maintaining desired coating film properties.
Solution Approach 2:
The patent applies the principle of local quality by using specific types of rings (benzene and cyclohexane) in controlled amounts within the polyester resin structure. This localized incorporation provides smoothness and chipping resistance at specific molecular sites without compromising overall storage stability of the coating composition.
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 solution results in a coating film with excellent finished appearance, storage stability, chipping resistance, and waterproof adhesiveness, addressing the limitations of previous systems by improving layer cohesion and physical properties.
Implementation Method 1
enhancing dispersion stability
Implementation Method 2
curing properties
Data Source
AI summary
Provided are: an aqueous coating composition which is capable of giving coating films having excellent chipping resistance without lowering the finish; and a method for forming a multilayered coating film. The aqueous coating composition comprises an acrylic-modified polyester resin (A) comprising an acrylic moiety and a polyester moiety, a crosslinking agent (B), and an epoxy phosphoric acid ester compound (C), wherein the acrylic-modified polyester resin (A) contains a polyoxyalkylene-group-containing unsaturated monomer having a weight-average molecular weight of 400 or higher as a monomer component of the acrylic moiety and the polyester moiety is configured of components, 50 mass% or more of which is accounted for by a C6 or higher compound, the content of the epoxy phosphoric acid ester compound (C) being 0.1-10 parts by mass per 100 parts by mass of the sum of the solid components of (A) and (B).