This book discusses the diverse array of particles that are found in coatings from both a physical and a performance standpoint. It also describes the fundamentals of particle behavior and shows how these affect the performance and properties of their end-use applications. It consists of nineteen chapters, demonstrating the wide range of types of particles found in coatings as well as the diversity of the important attributes they hold. The authors also present a forward looking view of current issues and trends in the coatings industry. In addition, a chapter on the use of particles in paper laminate, a closely aligned field, is included. This book is of interest to formulators of any type of coatings as well as researchers in aligned fields that use high volumes of small particles, such as the plastics and paper industries.
Author(s): Michael Diebold, Steven De Backer, Philipp M. Niedenzu, Brett R. Hester, Frank A. C. Vanhecke
Publisher: Springer
Year: 2022
Language: English
Pages: 717
City: Cham
Preface
Contents
Part I Introduction to Small Particles
1 The Behavior of Small Particles
Introduction
Physical Laws Governing Small Particles
The Forces of Nature
The Nature of Forces
The Balance of Forces in Large and Small Particles
Properties of Small Particles
Shape
True Density and Bulking Value
Surface Properties
Interactions with Light
Summary
References
2 The Physical Properties of Small Particles
Introduction
Particle Size and Size Distribution
Defining a Particle
Defining a Particle Size
Particle Size Distributions
Analytic Techniques
Gas Absorption Measurements
Surface Area
Pore Characterization
Surface Energy, Contact Angle, and Wettability
Bulk Density, Bulk Flow, and Powder Compressibility
Particle Packing
Measurement
Oil Absorption
Thermal Techniques
TGA
DSC
Elemental Analysis
Crystalline Phase Composition
Microscopy
Surface Charge
Controlling Surface Charge
Measuring Surface Charge
pH and Acid/Base Capacity
Optical Properties
Summary
References
Part II Optical Properties
3 Light Scattering 1—The Physics of Light Scattering
Introduction
Light and Light Scattering
Light Scattering Mechanisms
The Scattering Cross Section
Light Scattering by a Single Particle—Mie Scattering
Mie Analysis of Light Scattered by a Single Particle in a Polymer Matrix
The Scattering Volume
Scattering Direction
Scattering by Groups of Particles—Multiple and Dependent Light Scattering
Summary
References
4 Light Scattering 2—Light Scattering in Crowded Systems
Introduction
Particle Volume in Paints—The PVC
Measuring Particle Concentration
The Critical Pigment Volume Concentration (CPVC)
Particle Packing in Crowded Systems
The Opacity Versus PVC Curve
Visualizing the Loss of Scattering Efficiency Due to Dependent Light Scattering
Quantifying the Loss of Scattering Efficiency Due to Dependent Light Scattering
Making the Opacity Versus PVC Curve
Significance of the Curve Maximum
Curve Shape Below the CPVC
Mathematical Analysis
Examples of Opacity Versus PVC Curves
Quantifying the Opacity Loss Due to Scattering Volume Overlap
The Effective TiO2 PVC
The Effect of Large Extender Particles on TiO2 Crowding
The Effect of Small Extender Particles on TiO2 Crowding
Using the Opacity Versus PVC Curve to Measure the Effective TiO2 PVC
Measuring the CPVC
Opacity Above the CPVC
Dry Hide
Porosity Index
Specialized TiO2 Grades for Paints Formulated Above the CPVC
Oiled Hide
Wet Hide
Particle Size for Optimal Light Scattering
Light Scattering in Paper Laminates
Summary
Appendix
References
5 Color 1—Seeing Color
Introduction
The Nature of Light
The Nature of Color
Primary Colors and Color Mixing
Color as a Property
Hue, Lightness, and Saturation
The Achromatic “Colors”—Black, White, and Gray
Components of Color Vision
The Eye
Sources and Illuminates
The Reflectance Spectra
The Stimulus Spectrum
Metamerism
Physiological Factors
Summary
References
6 Color 2—Measuring Color
Introduction
Characterizing Colors
Systems Based on Cataloging Colors
Quantifying Colors Instrumentally
Describing Spectral Colors
Describing Complex Colors
The 1931 Standard Observer
x, y, and z Chromaticity Coordinates and the 1931 CIE xy Chromaticity Diagram
Perceptual Uniformity
Perceptually Uniform Color Spaces
CIE L*a*b*
Miscellany
Color Blindness
Color Vision in Non-humans
Are There Colors That We Cannot See?
Summary
References
Part III Particle Types
7 White Pigments
Introduction
Pigment Manufacture
Sulfate Process
Chloride Process
Property Differences
Surface Treatment
Finishing
Pigment Design
Particle Size
Durability
Dispersibility
Gloss
Opacity
Highly Treated Grades
Alternative White Pigments
Alternative Particles
Entrained Air
Summary
References
8 Color Pigments
Introduction
Light Absorption
The Electronic Nature of Atoms and Molecules
Simultaneous Light Absorption and Light Scattering
Pigment Families
Comparing Pigments to Dyes
Organic Pigments
Inorganic Pigments
Comparison Between Organic and Inorganic Pigments
Special Effects Pigments
Important Pigment Properties
Color
Transparency and Opacity
Lightfastness
Crystal Structure
Particle Size
Dispersibility
Pigment Manufacture
Organic Pigments
Inorganic Pigments
Pigment Concentrates
Pigment Nomenclature
Summary
References
9 Extender Particles
Introduction
Important Extender Properties
Classification of Extenders
The Carbonates
Silicates
Silicas
Barium Sulfate
Calcium Sulfate
Production of Mineral Extenders
Natural Extenders
Synthetic Extenders
Surface Treatment of Extenders
Summary
References
10 Resin Particles
Introduction
Comparison of Solvent-Borne and Water-Borne Coatings
Coalescence
Factors Affecting Coalescence and Film Formation
Tg and MFFT
Coalescing Agents
Binding Power Index
Specialized Resin Particles for Improved Opacity
Hollow Sphere Opaque Polymer
Reactive Resin and Resin/TiO2 Composite Particles
Summary
References
Part IV Aspects of Formulation
11 Dispersion of Small Particles in Liquid Paints
Introduction
The Importance of Good Particle Dispersion
Impacts on Paint Quality
The Dispersion Process
Wetting
Particle Separation and Dispersion
Particle Stabilization
Dispersants
Dispersant Architecture
Small Ions
Dispersant Demand
Dispersant Selection
Summary
References
12 Dispersion of Small Particles in Plastics
Introduction
Particle–Particle Attractive Forces
Dry Blending
Particle Wetting
Disruption of the Agglomerate Structure Using Shear
Examples of Particle Dispersion into Plastic Resin
Dispersive/Distributive Mixing with a Two-roll Mill
Dispersive/Distributive Mixing with an Internal Batch Mixer
Dispersive/Distributive Mixing with a Single-Screw Extruder
Summary
References
13 Measurement of the Optical Properties of Paints and Plastics
Introduction
Contrast Ratio
Concept
Limitations
Spread Rate
Kubelka–Munk Framework
Application of the Kubelka–Munk Equations to Spread Rate
Application Rate as Drawndown
Calculation of SX and KX
Reflectance of a Film at “Infinite” Thickness—R∞
The Judd Graph
Calculation of Spread Rate
Spread Rate at Another Value of R∞
R∞ Values Greater Than 1.0
Examples and Commentary
Applied Hide
Traditional Methods to Assess the Applied Hiding of an Architectural Coating
An Alternative Method for Applied Hide
Applied Hide Example
Factors Affecting Applied Hide
Paint Rheology
Tinting Strength
Tinting Strength of the White Pigment
Tinting Strength of the Color Pigment
Color Development and Shear Strength Uniformity
Undertone
Summary
References
14 Durability of Paints, Plastics, and Paper Laminates
Introduction
The Electronic Structure of Network Solids
Degradation Pathways
The TiO2 Photocatalytic Cycle
The Effect of TiO2 on Direct Degradation
Thermal Degradation
Ultimate Durability
The Concept of “Ultimate” TiO2 Pigment Durability
Manifestations of Degradation
Changes at the Film Surface—Erosion and Contraction
Gloss Loss
Chalking
Color Shift
Plastics Yellowing
Photodegradation of Polyvinyl Chloride
Photodegradation in Polyolefin
Paper Laminate Photo-Graying
Paper Laminate Durability in Compact Board Applications
Factors that Determine the Effect of TiO2 Pigment on Polymer Durability
Encapsulating Surface Coating
The Effect of TiO2 Dispersion on Chalking
The Effect of TiO2 Dispersion on Gloss Retention
The Two-Component Approach to Gloss Retention
The Effect of Relative Degradation Rates on Gloss Retention
Measuring Degradation
Natural Test Methods
Accelerated Test Methods
Methods Based on Early Results from Natural Weathering Exposures
Methods Based on Increased Exposure Intensity
“Reversals” and the Difficulty of Accelerated Weathering Tests
TiO2 Lab Tests
Measurement of Reaction Products
TiO2 Photocatalytic Rate of a Simple Redox Reaction
Indirect Tests for TiO2 Durability
Summary
References
Part V Formulation
15 Formulating with Color
Introduction
Comparing Additive and Subtractive Mixing
The Principles of Simple Light Absorption
Quantifying Light Absorption
Light Absorption by Non-Scattering Mixtures
Subtractive Primaries
Metamerism Revisited
Application to Paints
Colored Paints
Color Matching
One-Constant Kubelka–Munk Theory and Practice
Calculating the Colors of Paint Mixtures
The Saunderson Correction
Worked Examples
Two-Constant Kubelka–Munk Theory
Limitations of the Kubelka–Munk Analysis of Color Matching
Inks
Summary
References
16 Formulating Paints with Small Particles
Introduction
Composition of Paints
Important Paint Properties
Opacity, Color, and Brightness
Gloss
Mudcracking
Scrub Resistance
Degree of Dispersion
Durability
Substrate Protection
Rheology
Environmental Footprint
Strategies for Optimizing Hiding Power
Principles of Reformulation
Conventional Extenders
Nano-Spacer Extenders
Resin Particles
Composite Particles
Encapsulated Air
Light Absorption
Cost Optimization
Considerations When Formulating Above the CPVC
The Consequences of Air Pores
Cost Optimization Above the CPVC
Semi-Empirical Approach to Optimization
Development and Optimization of Paint Formulas
An Example of a DOE
Summary
References
17 Formulating Plastics with Small Particles
Introduction
Description of Solids in Plastics
Formulation with Solid Particles
Additives that Influence Viscosity at High Solids Volume
Mixing Particles of Different Chemical Composition (Calcium Carbonate with Titanium Dioxide)
Example of Formulation Using Particle Size for Optical Properties
Miscellaneous Properties Affected by Particles
Summary
References
18 Application to Décor Paper for Use in Laminates
Introduction
Décor Paper Properties and the Impact of TiO2
The Role of Décor Paper in the Lamination Process
Comparing TiO2 Crowding in Laminates to Crowding in Coatings and Plastics
Appearance Uniformity and Formation
Laminate Grade TiO2 Pigments
Surface Chemistry
TiO2 Dispersion
TiO2 Retention
Tools for Analyzing Décor Paper and Laminate Panels
Opacity and TiO2 Efficiency
Formation
Nano Computer Tomographic Analysis
Application of Nano CT
Study 1—Effect of Microstructure on Formation
Study 2—Development of Structure Through the Production Process
Study 3—Effect of TiO2 Level on Formation and Pore Content
An Alternative Method to Quantify TiO2 Clustering
Case Histories
Impact of TiO2 and Pore Content on Impregnation Behavior
Impact of TiO2 and Pores on Print Quality and Resin Impregnation Speed
Summary
References
Part VI Future Looking
19 Issues and Emerging Trends
Introduction
Nanoparticles
Photocatalytic Destruction of Pollutants
Digitization, Machine Learning, Artificial Intelligence, and Industry 4.0
Sustainability Challenges
Legislative and Regulatory Considerations
Life Cycle Assessment
Reduce
Re-Use
Recycle
Lower VOC Paints
Biocide-Free Coatings
Heat Reflective Coatings
Brighter Interiors for Reduced Electricity Usage
Summary
References
