Clear Coating Composition for Low Viscosity and High Solid Content
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Solution Overview
Problem
High solidification in coating compositions increases viscosity, leading to deteriorated workability and smoothness of the resulting coating film, along with appearance abnormalities such as sagging on vertical or inclined surfaces, which fails to meet the performance and quality requirements for automobile components.
Innovation Solution
A clear coating composition is formulated with a combination of hydroxy group-containing acrylic resin, polyester resin, a polyol compound with specific hydroxyl value and molecular weight, polyisocyanate compound, organic dispersive particles, and a cellulose derivative, which maintains low viscosity even at high solid content, ensuring smoothness and hardness of the coating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high solidification is used to reduce VOC, then VOC reduction is achieved, but viscosity increases leading to deteriorated workability and smoothness
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol compound to a specific low range (100-10000) and controls the hydroxyl value parameter (>200 mg KOH/g), which allows the coating composition to maintain low viscosity even at high solid content (50% or more), thereby improving workability while reducing VOC
Solution Approach 2:
The patent creates a composite coating system by combining specific resins (acrylic resin with Tg 0-50°C, polyester resin), polyol compound, polyisocyanate compound, and additives in controlled proportions, achieving both high solid content and low viscosity through synergistic material composition
2Object-generated harmful factors
If high solidification is used to reduce VOC, then VOC reduction is achieved, but smoothness of coating film deteriorates
Solution Approach 1:
By controlling the molecular weight of polyol compound within 100-10000 and hydroxyl value above 200 mg KOH/g, the patent achieves low viscosity that prevents sagging and maintains smoothness, while simultaneously achieving high solid content for VOC reduction
Solution Approach 2:
The patent uses organic dispersive particles (average particle size 0.01-5 μm) to locally modify the coating composition, improving smoothness by preventing defects while maintaining the overall high solid content formulation
3Ease of operation
If molecular weight of resin component is reduced to decrease viscosity, then viscosity decreases, but hardness and water resistance deteriorate
Solution Approach 1:
The patent selects acrylic resin with glass transition temperature of 0-50°C and polyester resin with specific hydroxyl values, creating a balanced resin system that provides both low viscosity and high hardness through optimized molecular structure and crosslinking density
Solution Approach 2:
The patent combines multiple resin types (acrylic and polyester) with polyol compound and polyisocyanate to create a crosslinked coating film that achieves both low viscosity for ease of application and high hardness for durability, resolving the contradiction between viscosity and hardness
4Ease of operation
If molecular weight of resin component is reduced to decrease viscosity, then viscosity decreases, but water resistance deteriorates
Solution Approach 1:
The patent uses the combination of polyester resin and polyol compound with polyisocyanate to create a crosslinked network structure that provides excellent water resistance, while the low molecular weight polyol maintains low viscosity for ease of application
Solution Approach 2:
By controlling the hydroxyl value of polyol compound above 200 mg KOH/g and molecular weight between 100-10000, the patent achieves optimal balance between viscosity and water resistance through controlled crosslinking density and hydrophilicity
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 a clear coating film with good appearance and high performance, maintaining low viscosity over a long pot life, thus preventing rapid viscosity increase during film formation and enhancing workability and smoothness.
Implementation Method 1
a polyol compound (c) other than the hydroxy group-containing acrylic resin (a) and the hydroxy group-containing polyester resin (b)
Implementation Method 2
organic dispersive particles (e)
Data Source
AI summary
Provided is a clear coating composition having a sufficiently low viscosity even being highly solid from which a coating film having a good appearance and high performance can be obtained. A clear coating composition including a hydroxy group-containing acrylic resin (a), a hydroxy group-containing polyester resin (b), a polyol compound (c) other than the hydroxy group-containing acrylic resin (a) and the hydroxy group-containing polyester resin (b), a polyisocyanate compound (d), organic dispersive particles (e), and a cellulose derivative (f), in which the polyol compound (c) has a hydroxyl value of more than 200 mg KOH/g and 1000 mg KOH/g or less and a molecular weight of 100 or more and 1000 or less.