Base Coating Composition with High Solid Content and Viscosity Recovery

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Solution Overview

Problem

Existing base coating compositions face challenges in achieving high design properties, adhesion, and water resistance while maintaining environmental considerations, particularly in terms of energy efficiency and facility load, as they often require energy for drying and have limitations in incorporating environmental considerations effectively.

Innovation Solution

A base coating composition comprising a pigment, hydroxy group-containing acrylic resin, blocked isocyanate compound, and crosslinked polymer fine particles, with a high solid content and specific viscosity recovery properties, which enhances adhesion and design properties while reducing energy consumption and facility burden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an aqueous base coating composition is used, then environmental consideration is improved, but energy consumption for drying and facility load increase

Engineering Contradiction:
Improveenvironmental considerationVSAvoidenergy consumption for drying
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The invention changes the parameter of solid content from conventional levels to 35% or higher, and controls the viscosity recovery rate to be 90% or more. This allows the use of a solvent-based composition with high solid content that reduces energy consumption while maintaining environmental considerations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite resin system combining hydroxy group-containing acrylic resin (B) and acrylic resin (E) with different weight average molecular weights. This composite approach enables high solid content (35% or more) while achieving the required viscosity recovery rate of 90% or more, resolving the contradiction between environmental consideration and energy consumption.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If a high-solid-content solvent-based coating material is used, then energy consumption is reduced, but control of coating film quality and design properties becomes difficult

Engineering Contradiction:
Improveenergy consumptionVSAvoidcoating film quality control
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The invention precisely controls the parameters of weight average molecular weight for both resins (B) and (E), and the viscosity recovery rate (90% or more). These parameter controls enable high solid content formulation while maintaining excellent coating film quality and design properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite resin system of hydroxy group-containing acrylic resin (B) and acrylic resin (E) with different molecular weights provides synergistic effects that enable both high solid content and precise control of coating film quality, resolving the contradiction between energy reduction and manufacturing precision.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the weight average molecular weight of the hydroxy group-containing acrylic resin is increased, then adhesion and water resistance are improved, but viscosity and ease of coating work deteriorate

Engineering Contradiction:
Improveadhesion and water resistanceVSAvoidease of coating work
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention segments the resin system into two components with different molecular weights: hydroxy group-containing acrylic resin (B) with weight average molecular weight of 10,000 or more and 20,000 or less for adhesion and water resistance, and acrylic resin (E) with weight average molecular weight of 3,000 or more and 7,500 or less for flow and ease of coating work. This segmentation resolves the contradiction between reliability and ease of operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The composite resin system combines high molecular weight hydroxy group-containing acrylic resin (B) for adhesion and water resistance with lower molecular weight acrylic resin (E) for ease of coating work, achieving both improved reliability and operational ease simultaneously.

Inventive Principle:
Principle #40Composite materials

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 superior adhesion, water resistance, and design properties with reduced energy consumption and facility burden, forming a coating film with improved appearance and reduced defects like peeling, while maintaining high solid content and environmental considerations.

Implementation Method 1

a base coating composition comprising a pigment (A); a hydroxy group-containing acrylic resin (B); a blocked isocyanate compound (C); crosslinked polymer fine particles (D)

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

aqueous base coating compositions inevitably need energy to evaporate water for drying or curing, and have a large load on facilities

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a viscosity recovery rate V21V1, which is a ratio of V2 to V1, is 90% or more

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS20230374339A1Base coating material composition and coated article
Publication Date: 2023.11.23 NIPPON PAINT AUTOMOTIVE COATINGS

AI summary

The present invention provides a base coating composition capable of forming a base coating film superior in design property (e.g., unevenness of a luster pigment), adhesion, and water resistance while satisfying environmental considerations such as shortening of drying time, and also provides a coated article obtained from the base coating composition. The present invention provides a base coating composition comprising a pigment (A), a hydroxy group-containing acrylic resin (B), a blocked isocyanate compound (C), crosslinked polymer fine particles (D) insoluble and stably dispersed in a solution of the hydroxy group-containing acrylic resin (B), and an acrylic resin (E) having a weight average molecular weight different from that of the hydroxy group-containing acrylic resin (B), wherein the specific hydroxy group-containing acrylic resin (B) is used and a viscosity recovery rate is adjusted. The present invention also provides a coated article formed using a base coating composition.