Effect Pigment Dispersion for Multilayer Coating Film

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Solution Overview

Problem

Existing paint technologies fail to provide a stable and water-resistant effect pigment dispersion that effectively forms metallic or pearly luster in coatings, especially after storage, and do not achieve satisfactory results in terms of gloss and graininess.

Innovation Solution

An effect pigment dispersion containing water, a wetting agent, and a phosphate-group-containing cellulose-based rheology control agent, with specific solids content and viscosity ranges, is used to form a multilayer coating film by applying the dispersion to a colored coating film and then a clear paint, achieving a 60-degree specular gloss of 90 to 240.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional aqueous paint compositions containing flake-effect pigment are used, then the paint can be applied to substrates, but the coating film lacks satisfactory metallic or pearly luster

Engineering Contradiction:
Improvemetallic or pearly lusterVSAvoidcoating quality
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention changes the viscosity parameter of the aqueous paint composition to a specific range (500 to 5000 cP at 6 rpm) and controls the solids content (0.1 to 10 parts by mass per 100 parts by mass of all components), which enables the flake-effect pigment to achieve proper orientation and arrangement on the substrate, thereby producing satisfactory metallic or pearly luster

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces a specific type of rheology control agent (cellulose-based with phosphate group, carboxyl group, or sulfate group) as an intermediary substance that mediates between the flake-effect pigment and the aqueous medium, enabling stable dispersion and proper flow characteristics that lead to excellent metallic or pearly luster in the coating film

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If effect pigment dispersion is stored for a predetermined period before application, then storage stability is required, but existing dispersions show degradation in metallic luster and water resistance

Engineering Contradiction:
Improvestorage stabilityVSAvoidwater resistance and metallic luster retention
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention optimizes the viscosity parameter (500 to 5000 cP at 6 rpm) and solids content (0.1 to 10 parts by mass per 100 parts by mass of all components) of the effect pigment dispersion, which prevents pigment aggregation and maintains dispersion stability during storage, ensuring retention of metallic luster and water resistance properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a specifically designed rheology control agent (cellulose-based with phosphate, carboxyl, or sulfate groups) as an intermediary that stabilizes the dispersion system during storage and maintains the performance characteristics (metallic luster and water resistance) even after predetermined storage periods

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the coating film is applied with standard viscosity, then application is straightforward, but the resulting film has poor water resistance and graininess

Engineering Contradiction:
Improveapplication simplicityVSAvoidwater resistance and surface smoothness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention specifies a particular viscosity range (500 to 5000 cP at 6 rpm) for the aqueous paint composition, which optimizes the flow and leveling characteristics during application, enabling the coating to form a smooth, grain-free film with excellent water resistance while remaining easy to apply

Inventive Principle:
Principle #35Parameter changes

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 provides a stable and water-resistant effect pigment dispersion that forms a multilayer coating film with excellent metallic or pearly luster and improved storage stability, achieving the desired gloss and reducing graininess.

Implementation Method 1

a phosphate-group-containing cellulose-based rheology control agent (C), with the effect pigment dispersion having a viscosity of 100 to 10000 mPa·sec as measured with a Brookfield viscometer at a rotational speed of 6 revolutions per minute

Methodology Applied
Scientific EffectRheology control:

Implementation Method 2

a wetting agent (A)

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentUS12054631B2Bright pigment dispersion and method for forming multilayer coating film
Publication Date: 2024.08.06 KANSAI PAINT CO LTD

AI summary

The problem to be solved by the present invention is to provide an effect pigment dispersion that exhibits excellent water resistance, that can form metallic or pearly luster, and that further exhibits high stability; and to provide a method for forming a multilayer coating film. The present invention provides an effect pigment dispersion that contains water, a wetting agent (A), a flake-effect pigment (B), and a phosphate-group-containing cellulose-based rheology control agent (C). The effect pigment dispersion has a solids content of 0.1 to 10 parts by mass, per 100 parts by mass of all of the components of the effect pigment dispersion; and has a viscosity of 100 to 10000 mPa·sec as measured with a Brookfield viscometer at a rotational speed of 6 revolutions per minute.