Coating Composition Balancing Appearance and Scratch Resistance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing clear coating compositions face challenges in achieving a balance between improving the appearance and enhancing scratch resistance and acid resistance, often resulting in inferior properties when attempting to enhance one aspect at the expense of the other.

Innovation Solution

A coating composition comprising a hydroxyl group-containing acrylic resin, a melamine resin or an unblocked isocyanate compound, and a half-ester group-containing copolymer, with specific molecular weight and acid value ranges, along with a particulate additive, to form a coating film with improved appearance and balanced scratch and acid resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the blending amounts of melamine resin and plasticizer are adjusted to improve the appearance of the coating film, then the appearance and design are improved, but the scratch resistance and acid resistance are lowered

Engineering Contradiction:
ImproveappearanceVSAvoidscratch resistance
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent introduces a novel parameter - the acid value of the polyester resin component - and establishes specific ranges (50-400 mg KOH/g for high acid value polyester, and controlled total acid value) to simultaneously achieve good appearance, scratch resistance, and acid resistance. This parameter change enables balancing previously conflicting properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system combining multiple resin components (hydroxyl-containing polyester resin, high acid value polyester, melamine resin) with specifically controlled acid values and blending ratios. This composite approach allows the synergistic effect of different components to achieve balanced performance in appearance, scratch resistance, and acid resistance that single-component systems cannot achieve.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If the blending amounts of melamine resin and plasticizer are adjusted to improve the appearance of the coating film, then the brightness and smoothness are improved, but the acid resistance is lowered

Engineering Contradiction:
ImprovebrightnessVSAvoidacid resistance
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent controls the acid value parameter of the polyester resin components to simultaneously achieve good appearance (brightness, smoothness) and acid resistance. By specifying high acid value polyester (50-400 mg KOH/g) blended in controlled amounts, the patent finds an optimal parameter range that balances optical properties with chemical resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different functional components in specific proportions: the high acid value polyester provides acid resistance and contributes to appearance, while the melamine resin provides hardness and gloss. This local quality distribution of functions among components enables simultaneous achievement of brightness and acid resistance.

Inventive Principle:
Principle #3Local quality

3Strength

If the acid value of polyester resin is increased to enhance scratch resistance, then the scratch resistance improves, but the appearance quality deteriorates

Engineering Contradiction:
Improvescratch resistanceVSAvoidappearance quality
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent utilizes the acid value parameter as a key control variable, establishing that high acid value polyester (50-400 mg KOH/g) when blended in specific amounts (10-50 parts per 100 parts resin component) provides both scratch resistance and good appearance, contrary to conventional wisdom that high acid value degrades appearance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a multi-phase resin system with different acid value components that form a complex network structure upon curing. This structure provides both mechanical strength (scratch resistance) and optical quality (appearance) through the distributed functional properties of the composite resin system.

Inventive Principle:
Principle #31Porous materials

4Ease of operation

If conventional clear coating compositions are used, then the processability is maintained, but the balance between appearance, scratch resistance, and acid resistance cannot be achieved

Engineering Contradiction:
ImproveprocessabilityVSAvoidbalanced coating film properties
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent maintains processability by using conventional melamine resin curing agents and standard application methods, while achieving balanced coating film properties through controlled acid value parameters and specific blending ratios of resin components. The formulation remains compatible with existing manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal coating composition that simultaneously provides multiple functions: the hydroxyl-containing polyester resin provides adhesion and flexibility, the high acid value polyester provides scratch and acid resistance, and the melamine resin provides hardness and gloss. This multi-functional system maintains ease of operation while achieving reliable balanced performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 coating composition achieves superior scratch resistance, acid resistance, and appearance, including improved smoothness, sharpness, and brightness, while preventing color reversion, and can be used in a multilayer coating film formation process.

Implementation Method 1

a half-ester group-containing copolymer (C) that is a copolymer of a polymerizable unsaturated monomer (a) having a half-esterified acid anhydride group and another copolymerizable monomer (b)

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

a hydroxyl group-containing acrylic resin (A)

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS11732154B2Coating composition and method for forming multilayer coating film
Publication Date: 2023.08.22 NIPPON PAINT AUTOMOTIVE COATINGS

AI summary

The present invention provides a coating composition capable of forming a coating film having a good appearance and design of a coating film and having coating film properties such as scratch resistance with a good balance. Furthermore, the present invention provides a method for forming a multilayer coating film including forming a coating film using the coating composition of the present invention.