Specialty Additives for Architectural Coatings PNWSCT Coatings Fest 2014 Rocky Prior, Charlie Hegedus, Ingrid Meier Copyright © Air Products and Chemicals, Inc. 2014 Objective • Provide guidance for selection of specialty additives for architectural coatings • Discuss a variety of different additive types • Provide general chemistry descriptions • Describe unique properties and benefits • Provide performance examples and guidelines for additive selection Copyright © Air Products and Chemicals, Inc. 2014 Multi-Functional Surfactants • Improve substrate and pigment wetting. Increase coating flow and leveling • Can affect other properties such as adhesion, foam, rheology, minimum film formation temperature, etc. Traditional Surfactants Low Foam Dynamic Wetting Agents Superwetting Surfactants Coalescing Surfactants Copyright © Air Products and Chemicals, Inc. 2014 Traditional Surfactants Used in Architectural Coatings • Provide surface tension reduction to wet both pigment and substrate; can improve color development and color acceptance • Also can improve other properties such as viscosity stability, freeze-thaw stability, scrub resistance • Tend to stabilize foam, requiring defoamer • Primarily nonionic surfactants that range in HLB • Originally, alkylphenol ethoxylates (APEs) and modified APEs dominated • Non-APE alcohol ethoxylates are replacing APEs - Comparable or improved performance to APE surfactants - Can often be “drop in” replacements Copyright © Air Products and Chemicals, Inc. 2014 Low Foam Dynamic Wetting Agents • Gemini structures that contain two amphiphilic groups linked with a short “spacer” hydrophile hydrophobe • Unique molecular structures do not stabilize foam and prevent these surfactants from interacting strongly with other system components • This feature makes these wetting agents ideal for use in Architectural Coatings because they can perform their intended function without adversely affecting other properties Copyright © Air Products and Chemicals, Inc. 2014 Low Foam Dynamic Wetting Agent: No Adverse Viscosity Effects in Vinyl Acrylic Wall Paint 105 White semi-gloss wall and trim vinyl acrylic interior paint with 0.5% by weight surfactants. VOC = 35 g/L. Stormer viscosity (KU) 100 95 90 85 80 75 70 65 60 No added surfactant Surfynol 420 NPE OPE-1 OPE-2 OPE-3 OPE-4 Surfynol® 420 surfactant does not affect paint viscosity. Other surfactants such as nonyl phenol ethoxylates (NPE) and octyl phenol ethoxylates (OPE-1 through 4) dramatically reduce viscosity which can cause pigment settling and poor application with defects such as sags. Copyright © Air Products and Chemicals, Inc. 2014 Superwetting Surfactants Rapidly wet extremely low surface energy substrates (e.g., wood, old paint, contaminated surfaces, plastics, etc.) - Very low dynamic surface tensions - Extremely fast wetting rates and low contact angles Copyright © Air Products and Chemicals, Inc. 2014 Superwetting Surfactants Commercial paint 0.9% Dynol™ 360 0.9% Dynol™ 800 Vinyl acrylic interior paint applied to a contaminated surface crawls and has major film defects. The same paint with 0.9% Dynol™ 360 surfactant and Dynol™ 800 surfactant wets the contaminated surface perfectly. Copyright © Air Products and Chemicals, Inc. 2014 Coalescing Surfactants • Unique surfactant structures - Enable surface tension reduction at <1 wt.% - Dynol™ 360 and Surfynol® AD01 surfactants provide low foam dynamic wetting - As coalescing surfactants, they also assist in latex coalescence and film formation (very unique property) • Can be used to replace and reduce co-solvent - Reduce MFFT and / or VOC while maintaining other properties (e.g., hardness, scrub resistance, etc.) - NOT A PLASTICIZER – does not reduce hardness Copyright © Air Products and Chemicals, Inc. 2014 Coalescing Surfactants Coalescence and film formation of a polyurethaneacrylic latex topcoat. Adding 0.9% Dynol™ 360 surfactant eliminates the need for a solvent based coalescing aid. Copyright © Air Products and Chemicals, Inc. 2014 Lowering MFFT with Coalescing Surfactant – Dynol™ 360 Surfactant Minimum Film Formation Temperature (oC) 9 8 7 6 5 4 3 2 1 0 0 0.5 0.8 Weight Percent Coalescing Surfactant 1 Acrylic-polyurethane clear wood coating, 40% volume solids, VOC = 95 g/L. Copyright © Air Products and Chemicals, Inc. 2014 Wetting Agent Selection Guidelines for Architectural Coatings Superwetting Strongest Wetting Lower water solubility Strong dynamic wetting Dry pigment wetting No foam Moderate water solubility Moderate dynamic wetting Minimal foam Higher water solubility Stronger wetting, Lower Water Solubility, Greater foam control Efficient wetting, Higher HLB, Less foam control Dynol™ 800, 980 360 (*) Surfynol® 104, 420, 440, AD01 (*) (*) Coalescing surfactants Copyright © Air Products and Chemicals, Inc. 2014 Carbowet® GA-210 Surfynol 465, 485, PSA336 Wetting Agent Selection Guidelines • Match coating requirements to wetting agent properties: - Surface tension reduction (type of substrate) - Dynamic surface tension (application process) - Foam generation (or defoaming) performance - Compatibility (solubility and HLB) - Water resistance (HLB) - Minimum film formation temperature (MFFT) coalescing surfactant - Viscosity effects (e.g., interactions with pigment dispersants, rheology modifiers) - Environment, health, and safety requirements (e.g., low/no VOC, HAPs, APE, etc.) Copyright © Air Products and Chemicals, Inc. 2014 Dispersants and Surfactants in Pigment Grinds and Dispersions Used in Architectural Coatings Improve pigment dispersion process, pigment wetting, grinding, color development, dispersion stability, rheology Dispersants Low Foam Dynamic Wetting Agents Grind Aids Stabilizing Surfactants (Co-Dispersants) Copyright © Air Products and Chemicals, Inc. 2014 Dispersants in Architectural Coatings • Dispersants are surface active molecules that orient on the pigment surface and prevents agglomeration and flocculation through stabilizing mechanisms - Specially designed polymers (high performance dispersants) - Commodity polymers (acrylic acids, styrene-acrylics, EO/PO block copolymers) – often used to disperse TiO2 - Some surfactant chemistries (alkylphenol ethoxylate types, alkyl ethoxylates, alkyl sulfonates, phosphates, etc.) • A variety of chemistries can be combined to create an optimally stabilized dispersion 15 Copyright © Air Products and Chemicals, Inc. 2014 Optimum Dispersant Provides Maximum Color Development and Viscosity Stability Carbon Black Dispersion Benchmark A Viscosity: 9350 cps Benchmark B Viscosity: gel Benchmark C Viscosity: 30 cps 15.0 parts Raven 5000 Ultra III, 31.3 parts Dispersant, 1.0 parts Surfynol DF 75, 52.7 parts water 16 Copyright © Air Products andand Chemicals, Inc.Inc. 2014 Copyright © Air Products Chemicals, 2014 ZetaSperse 3100 Dispersant Viscosity: 26cps F.A.Z.T. Formulator Assisting ZetaSperse Tool • Use F.A.Z.T. or Selector Guide to Choose Optimal Dispersant for Pigments or Fillers • An online tool that provides specific dispersant recommendations and starting point formulations • Accessible from mobile and desktop devices • Based on a database of >1500 global pigments • Formulas calculated from pigment properties, dispersant attributes and our own extensive testing and experience www.FAZT.com Copyright © Air Products and Chemicals, Inc. 2014 Surfactant Usage in Grinds and Dispersions in Architectural Coatings • Surfactants can enhance dispersion attributes and improve processing in the three dispersion steps: 1. Wetting Dry Particles 2. Milling/Grinding to Disperse Particles 3. Stabilizing Dispersed Particles • A variety of benefits can be achieved - Dry pigment wetting and deaeration - Milling efficiency and color development - Letdown compatibility and resistance to shock and flocculation - Dispersion viscosity and color stability 18 Copyright © Air Products and Chemicals, Inc. 2014 Dry Pigment Wetting and Deaeration • Dynamic wetting agents enable complete wetting and deaeration of pigments/particles during dispersion - Improves cut-in time - Enables a more efficienct milling process - Reduces microfoam and optimizes milling density 19 Copyright © Air Products and Chemicals, Inc. 2014 Dry Pigment Wetting and Deaeration 10 g of P.B. 15:3 added to surface of additive solutions Styrene-Acrylic Polymeric Dispersant Only Same Polymeric Dispersant + 0.3% Dynamic Wetting Agent 20 Copyright © Air Products and Chemicals, Inc. 2014 Milling/Grinding of the Pigment • Pigments agglomerate during the drying process, lowering performance • Milling is the process by which pigments are returned to an optimal particle size milling process Requires energy grinding, shearing, impacting additives optimize process 21 Copyright © Air Products and Chemicals, Inc. 2014 Grind Aids Improve Milling Efficiency • Grind aids can improve milling efficiency through optimal wetting and dynamic stabilization - Increased color development, gloss and hiding power - Reduced milling time; improved energy use - Dispersion stability and letdown benefits • Carbowet® GA-series surfactants are designed for these performance improvements With Grind Aid Greater milling effectiveness Without Grind Aid Greater milling efficiency Jumpstart from proper deaeration Copyright © Air Products and Chemicals, Inc. 2014 Grind Aid Surfactant Can Shorten Milling Time 0.3 wt.% Surfactant in an acrylic interior flat paint, 100 mm thick film 18 Particle size (D50, microns) 16 14 12 10 No Grind Aid 8 Carbowet GA-210 6 4 2 0 0 5 10 15 20 25 Milling time (minutes) 30 Copyright © Air Products and Chemicals, Inc. 2014 35 Grind Aid Surfactant Can Enable Replacement of TiO2 with CaCO3 0.3 wt.% Surfactant in an acrylic Interior Flat Paint, 100 mm thick film 0.98 0.975 Opacity 0.97 0.965 0.96 Control 0.955 0.95 Carbowet GA-100 0.945 Carbowet GA-210 0.94 0.935 0.93 0.925 0 10 20 30 40 50 Ratio of Replaced CaCO3 (%) Copyright © Air Products and Chemicals, Inc. 2014 60 Stabilizing Surfactant Dispersants for Resin-Containing Systems (Co-Dispersants) • ZetaSperse® 100-series dispersants are designed to enhance the stabilization and performance properties of ionic dispersants - Enhances letdown compatibility - Improves dispersion viscosity stability - Can lower dispersion viscosity allowing higher loadings • ZetaSperse 170 dispersant - Amine alkoxylate designed for acidic pigments such as some carbon blacks and mineral oxides • ZetaSperse 179 and 182 dispersants - Specialty high-HLB alcohol alkoxylates 25 Copyright © Air Products and Chemicals, Inc. 2014 Shock and Letdown Compatibility • The dispersant plays a large role in preventing issues when the pigment grind is let down • Surface tension gradients can drive exchange between dispersions prior to equilibrium - This can cause the molecules stabilizing the colorant to leave the pigment surface and migrate into the white base paint and vice versa • Surfactants may “buffer” the system by providing dynamic stabilization similar to benefits seen in milling - Balancing pigment-dispersant differences between the grind and the letdown formulations 26 Copyright © Air Products and Chemicals, Inc. 2014 Surfactant Selection Guidelines for Pigment Grinds and Dispersions Dry pigment wetting Faster milling Color development Letdown compatibility Color stability improvement Viscosity reduction Stabilization enhancement Stronger stabilization characteristics; Higher water solubility Efficient wetting and surface tension reduction; Lower water solubility Dynamic Wetting Agents Dynol™ 360 Surfynol® 420,104, AD01 Grind Aids Carbowet® GA100, GA210, GA211, GA221 Copyright © Air Products and Chemicals, Inc. 2014 Co-Dispersants ZetaSperse® 170, 179, 182 Surfactant Selection Guidelines for Pigment Grinds and Dispersions • With any dispersion, the stabilizing dispersant is identified first - F.A.Z.T. and ZetaSperse selectors • Other additives are selected to optimize the dispersion properties and process: - Dynamic wetting for incorporation and milling - Dynamic stabilization for milling and letdown compatibility - Equilibrium stabilization for robust dispersion, color, and viscosity stability 28 Copyright © Air Products and Chemicals, Inc. 2014 Defoamers and Deaerators • Reduce or eliminate foam at surface or in bulk of coating • Can affect other properties such as wetting Conventional defoamers Molecular defoamers Deaeators Copyright © Air Products and Chemicals, Inc. 2014 Conventional Defoamers • Organic oils or siloxane. May contain hydrophobic particles (silica, wax or polyurea) • Work by an incompatibility mechanism - Wet across bubble wall surface, weaken wall, bubble breaks - More incompatible -> stronger defoaming - More compatible -> weaker defoaming but less chance for craters Air phase Liquid phase Incompatible Defoamer Droplet Copyright © Air Products and Chemicals, Inc. 2014 Defoaming Siloxane Defoamer in Exterior Flat Paint: Optimized Defoaming Strength and Compatibility Silcone A Defoamer Airase® 5400 Defoamer Copyright © Air Products and Chemicals, Inc. 2014 Silcone B Defoamer Molecular Defoamers • Specific Gemini (twin) surfactant structures • Work by molecular displacement of surfactants stabilizing foam - Eliminate microfoam and macrofoam • “Wetting defoamers” – also providing wetting agent function B B Spacer Copyright © Air Products and Chemicals, Inc. 2014 Deaerators vs. Defoamers Defoaming Air phase Liquid phase Deaeration • Defoamers eliminate macrofoam – bubbles present on the surface of the paint • Deaerators eliminate microfoam (tiny air bubbles in bulk coating). Are less prone to diffuse to coating surface and difficult to remove. Copyright © Air Products and Chemicals, Inc. 2014 Siloxane Deaerator in an AirAssisted Spray Applied coating 100 micron 100 micron blank Organic def oamer 100 micron 100 micron Airase 8070 Traditional PES def oamer Copyright © Air Products and Chemicals, Inc. 2014 Defoamer and Deaerator Selection Guidelines Pigment Grinds High PVC High viscosity High shear Thick films Letdown Moderate PVC Moderate shear Clear coats Low PVC Low viscosity Thin films Stronger defoaming, less compatible More compatible, weaker defoaming Airase® 5100, 5200 Surfynol® DF58 Airase 4500, 5400, 5500 Surfynol DF-58 Copyright © Air Products and Chemicals, Inc. 2014 Surfynol MD20 Airase 5600, 5700 Defoamer and Deaerator Selection Guidelines • Match formulation and application requirements to defoamer properties and benefits - What are the paint characteristics: • Binder, PVC, viscosity, thickness, dry time, gloss - What surfactants are being used? Are they stabilizing foam? - Where and how does foam occur (grind, mixing, shaking, application); amount of agitation? - How is the paint produced? - How is the coating applied? - Macrofoam or microfoam? - Are silicones acceptable? Copyright © Air Products and Chemicals, Inc. 2014 Thank you tell me more www.airproducts.com Copyright © Air Products and Chemicals, Inc. 2014