Specialty Additives for Architectural Coatings PNWSCT Coatings Fest 2014 Rocky Prior, Charlie Hegedus, Ingrid Meier Copyright © Air Products and Chemicals,

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


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


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


Low Foam Dynamic Wetting Agents

• Gemini structures that contain two amphiphilic groups linked with a short “spacer”

• 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

hydrophile

hydrophobe


Low Foam Dynamic Wetting Agent: No Adverse Viscosity Effects in Vinyl Acrylic Wall Paint

No added surfactant

Surfynol 420 NPE OPE-1 OPE-2 OPE-3 OPE-460

65

70

75

80

85

90

95

100

105

Sto

rmer

vis

cosit

y (

KU

)

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.


White semi-gloss wall and trim vinyl acrylic interior paint with 0.5% by weight surfactants. VOC = 35 g/L.

Superwetting SurfactantsRapidly 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


0.9% Dynol™ 360Commercial paint 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.

Superwetting Surfactants


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


Coalescing Surfactants

Coalescence and film formation of a polyurethane-acrylic latex topcoat. Adding 0.9% Dynol™ 360 surfactant eliminates the need for a solvent based coalescing aid.


Lowering MFFT with Coalescing Surfactant – Dynol™ 360 Surfactant

0 0.5 0.8 10

1

2

3

4

5

6

7

8

9M

inim

um

Film

Form

ati

on

Te

mpera

ture

(oC

)

Weight Percent Coalescing Surfactant


Acrylic-polyurethane clear wood coating, 40% volume solids, VOC = 95 g/L.

Wetting Agent Selection Guidelines for Architectural Coatings

Moderate dynamic wetting

Minimal foam

Strong dynamic wetting

Superwetting

Carbowet® GA-210Surfynol 465, 485, PSA336

Surfynol® 104, 420, 440, AD01 (*)

Dynol™ 800, 980360 (*)

Higher water solubility

No foam

Lower water solubility

Moderate water solubility

(*) Coalescing surfactants

Dry pigment wetting

Strongest Wetting

Stronger wetting, Lower Water Solubility, Greater foam control

Efficient wetting, Higher HLB, Less foam control


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.)


Dispersants and Surfactants in Pigment Grinds and Dispersions Used in Architectural Coatings

Improve pigment dispersion process, pigment wetting, grinding, color development, dispersion stability, rheology

DispersantsLow Foam Dynamic Wetting AgentsGrind AidsStabilizing Surfactants (Co-Dispersants)


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

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ZetaSperse 3100 Dispersant

Viscosity: 26cps

Benchmark BViscosity: gel

Benchmark AViscosity: 9350 cps

Benchmark CViscosity: 30 cps

Carbon Black Dispersion

16 Copyright © Air Products and Chemicals, Inc. 2014

Optimum Dispersant Provides Maximum Color Development and Viscosity Stability

15.0 parts Raven 5000 Ultra III, 31.3 parts Dispersant, 1.0 parts Surfynol DF 75, 52.7 parts water


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


http://www.fazt.com/

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 Particles2. Milling/Grinding to Disperse Particles3. 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

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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

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Dry Pigment Wetting and Deaeration

Styrene-Acrylic Polymeric Dispersant Only

Same Polymeric Dispersant + 0.3% Dynamic Wetting Agent

10 g of P.B. 15:3 added to surface of additive solutions

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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

millingprocess

Requires energygrinding, shearing, impacting

additives optimize process

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Grind Aids Improve Milling Efficiency

Greater milling efficiency

With Grind Aid

Without Grind Aid

Jumpstart from proper de-aeration

Greater milling effectiveness

• 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


Grind Aid Surfactant Can Shorten Milling Time 0.3 wt.% Surfactant in an acrylic interior flat paint, 100 mm thick film

0 5 10 15 20 25 30 350

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4

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No Grind AidCarbowet GA-210

Milling time (minutes)

Part

icle

siz

e (

D50,

mic

rons)


Grind Aid Surfactant Can Enable Replacement of TiO2 with CaCO3

0.3 wt.% Surfactant in an acrylic Interior Flat Paint, 100 mm thick film

0.9250.93

0.9350.94

0.9450.95

0.9550.96

0.9650.97

0.9750.98

0 10 20 30 40 50 60

Control

Carbowet GA-100

Carbowet GA-210

Ratio of Replaced CaCO3 (%)

Op

acit

y


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

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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

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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 AgentsDynol™ 360

Surfynol® 420,104, AD01

Grind AidsCarbowet®

GA100, GA210,GA211, GA221

Co-DispersantsZetaSperse® 170, 179, 182

Surfactant Selection Guidelines for Pigment Grinds and Dispersions


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

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Defoamers and Deaerators

• Reduce or eliminate foam at surface or in bulk of coating

• Can affect other properties such as wetting

Conventional defoamersMolecular defoamersDeaeators


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 phaseI ncompatible

Defoamer Droplet Defoaming


Siloxane Defoamer in Exterior Flat Paint: Optimized Defoaming Strength and Compatibility

Silcone ADefoamer

Silcone BDefoamer

Airase® 5400Defoamer


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

A ASpacer

B B


Deaerators vs. Defoamers

• 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.

Air phase

Liquid phase

Defoaming

Deaeration


Organic defoamerblank

100 micron 100 micron

Airase 8070

100 micron

Traditional PES defoamer

100 micron

Siloxane Deaerator in an Air- Assisted Spray Applied coating


Low viscosity

Letdown

Pigment GrindsHigh PVC

Stronger defoaming, less compatible

More compatible, weaker defoaming

Surfynol MD20Airase 5600, 5700

Airase 4500, 5400, 5500

Surfynol DF-58

Airase® 5100, 5200Surfynol® DF58

Thin films

Moderate PVCModerate shear

High viscosityHigh shear

Low PVC

Thick films

Clear coats


Defoamer and Deaerator Selection Guidelines

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?


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Documents

Specialty Additives for Architectural Coatings PNWSCT Coatings Fest 2014 Rocky Prior, Charlie Hegedus, Ingrid Meier Copyright © Air Products and Chemicals,