Powder Coating Composition Bilayer Formation via Phase Separation
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Solution Overview
Problem
Current powder coating materials, such as acrylic and epoxy resin types, lack sufficient weather resistance, and while blending polyester and fluorinated resins can improve this, achieving a fluorinated resin layer and polyester layer with single coating operation is challenging, especially in forming a bilayer structure with excellent water, chemical, and weather resistance.
Innovation Solution
A powder coating composition comprising a fluorinated resin, a polyester polymer, a curing agent, and an ultraviolet absorber, where the polyester polymer is derived from C8-15 aromatic polybasic carboxylic acid compounds and C2-10 polyhydric alcohols, and the fluorinated resin is hydroxy group-containing, allowing for a single coating operation to form a bilayer structure with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyester resin and a fluorinated resin are blended to improve weather resistance, then weather resistance is improved, but the bilayer structure with distinct fluorinated resin layer and polyester layer cannot be formed with single coating operation
Solution Approach 1:
The patent changes the molecular weight parameters of the polyester polymer to a specific range (500-5,000 number average molecular weight) to control the phase separation behavior during curing. This parameter adjustment enables the formation of a distinct bilayer structure with a fluorinated resin layer and a polyester layer from a single coating application, resolving the contradiction between achieving weather resistance and forming the proper bilayer structure.
2Ease of manufacture
If conventional powder coating materials (acrylic, polyester, epoxy) are used, then ease of manufacture is maintained, but weather resistance is poor
Solution Approach 1:
The patent creates a composite powder coating material consisting of a fluorinated resin (A) and a specifically designed polyester polymer (B) with controlled molecular weight. This composite structure combines the excellent weather resistance of fluorinated resins with the manufacturability and film-forming properties of polyester resins, achieving both ease of manufacture and superior weather resistance.
3Reliability
If double coating is performed to form fluorinated resin layer and polyester resin layer, then weather resistance is improved, but process complexity increases
Solution Approach 1:
The patent merges the application of fluorinated resin and polyester resin into a single coating operation. By formulating a powder coating composition containing both resins with specific molecular weight characteristics, the system automatically phase-separates during curing to form the desired bilayer structure, eliminating the need for separate coating steps and reducing process complexity while maintaining weather resistance.
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 enables the formation of a cured film with excellent water resistance, chemical resistance, and weather resistance through single coating, with the fluorinated resin layer and polyester layer being layer-separated, improving durability and performance.
Implementation Method 1
a polyester polymer (B) which is a polyester polymer comprising units derived from a C8-15 aromatic polybasic carboxylic acid compound and units derived from a C2-10 a polyhydric alcohol compound
Implementation Method 2
a polyester polymer (B) which is a polyester polymer comprising units derived from a C8-15 aromatic polybasic carboxylic acid compound and units derived from a C2-10 a polyhydric alcohol compound
Implementation Method 3
the fluorinated resin (A) is a hydroxy group-containing fluorinated polymer (A1)
Implementation Method 4
a curing agent (C)... reacting reactive components in the powder coating composition
Implementation Method 5
an ultraviolet absorber (D)... which is selected from the group consisting of an inorganic ultraviolet absorber and an organic ultraviolet absorber
Implementation Method 6
a cured film which has a fluorinated resin layer and a polyester layer... the fluorinated resin layer and the polyester layer are layer-separated
Data Source
AI summary
Provided is a powder coating composition, whereby a cured film excellent in water resistance, chemical resistance and weather resistance, can be formed by single coating operation, wherein a fluorinated resin layer and a polyester layer are layer-separated in the process of melting and curing the powder coating composition. A powder coating composition comprising a fluorinated resin (A), a polyester polymer (B), a curing agent (C) and an ultraviolet absorber (D), wherein the polyester polymer (B) is a polyester polymer comprising units derived from a C8-15 aromatic polybasic carboxylic acid compound and units derived from a C2-10 a polyhydric alcohol compound.