In The name of godThehran University

Faculty of Chemistry

Water-borne coatings

Presentation By :Saeed Iranpour

Supervisor :Dr.S.Khoei

OutlineThree Groups of Protective CoatingsOrganic coatingsPaint Composition vehicleA Few Words About SolventsA Few Words About BindersPigmentinorganic & organic pigmens.AdditivesCoating SubstitutesAlternative CoatingsWaterborne Coatings Types of Waterborne Coatings Water-soluble paintsWater-dispersible paintsWaterborne Two-Component Latex paintsBinders for Water borne paintDriers forWater-Borne Coatings Formation of EmulsionsEmulsion Paints Patent list of formulation (wB.Paint)The Manufacture of Water-Borne Coatings.Operation in paint MixingWaterborne coatings Applications refrences

Three Groups of Protective Coatings

• Inorganic Coatings– Produced by chemical and anodic treatments– Include chromates, phosphates, oxides, and

anodized coatings

• Metallic Coatings– Include electroplates, prayed metal coatings, and

hot-dip coatings

• Organic Coatings– Include paints, lacquers, enamels, and varnishes

Organic Coatings• Three basic functions include:

– Protection of surfaces– Perform special functional job (camouflage)– Serve as decorative coating

Organic Coatings (cont.)• Acrylic Resins

– Excellent resistance to water, acids, alkali, etc.• Alkyd Resins

– Economic, durable, flexible, adhesion, color retention, and high gloss retention

• Cellulose Polymers– Tough, hard, durable material with fast air-drying

properties• Epoxy Resins

– Chemical resistant, tough, and durable• Polyurethane Coatings

– Hard, resistant, and possessing exterior durability

Paint Composition

solvents binders pigments

60% 30%, 2 to 3%

additives

7 to 8%,

vehicle

• In paint, the combination of the binder and solvent is referred to as the paint "vehicle." Pigment and additives are dispersed within the vehicle .

A Few Words About Solvents

• Solvents are added to coatings to disperse the other constituents of the formulation and to reduce viscosity, thereby enabling application of the coating.

• Aliphatic Hydrocarbons,(ketones (methyl ethyl ketone (MEK) and methyl

isobutyl ketone (MIBK)), alcohols, esters, and glycol ethers.)

• Aromatic Hydrocarbons (toluene, xylene, and the trimethyl benzenes), • Water is the best solvent for man & environment

A Few Words About Binders

Binders are chosen based on what physical and chemical properties are desired of the finished film.

• In general, metal coatings binders are:alkyds; water-based acrylics, epoxies, polyurethanes and

polyesters.

• Other Binders:• silicones have high heat resistance and superior resistance to

weather and water. • Vinyls are another binder that can have a wide range of

flexibility.• They are used extensively in marine applications, interior

metal can liners (e.g., polyvinylchloride), or structural wood finishes (e.g., polyvinylacetate)

Pigment

Colored pigments•red/yellow/black iron oxide, blue/green phtalocyanine and gilsonite

White pigmentslithopone and

titanium dioxide

Metallic pigmentsvermiculite (texture), flake aluminum (sparkle/metallic appearance), and titania and surface-modified talc (pearlescence)

Functional pigmentslimestone and clay (fillers); barium metaborate (preservatives); lithopone and zinc sulfide (UV stabilizers); nickel/copper/silver powders and barium titanate (conductive ability); and carbon black, silica, Attapulgus clay and fibers (reinforcement)

inorganic & organic pigmens.

Colored pigments are available in both

inorganic & organic compounds.

Inorganic pigments have high thermal stability and ultraviolet (UV) light stability.

Organic pigments are brighter and clearer than inorganic pigments

Additives

• Additives are materials that improve the physical and chemical properties of the coating.  Additives include surfactants, colloids and thickeners, biocides and fungicides, freeze/thaw stabilizers, coalescing agents, defoamers, plasticizers, flattening agents, flow modifiers, stabilizers, catalysts and antiskinning agents .A coating's characteristics can change significantly depending on which additives

Coating Substitutes

• Organic Solvent-Based Paints– Most common– Contains approx. 40 percent solids– Low transfer efficiency– High VOC content

• High-Solids– Higher % solids and lower % VOC– Improved transfer efficiency– May require a paint heater

Coating Substitutes

• Water-Based– High solids content, water is solvent– Benefits– Drawbacks

• Catalyzed or Two-Component– One liquid contains resins– Other liquid contains catalyst to promote

polymerization– Cure at low temperatures

Coating Substitutes

• Radiation Cured– Low VOC content– High capital investment

• Powder Coatings– 100% resin in dry powdered form– Must be cured in an oven– Now VOC emissions– Can collect/reuse overspray– High transfer efficiency

Alternative Coatings

• Vendors have developed a number of alternative coating technologies. Environmental compliance remains the principal driver for the development of new technologies

• These new technologies include: a) High-solids coatings b) Waterborne coatings c) Powder coatings d) Radiation-cured coatings e) Emerging technologies such as vapor permeation of injection

coatings and supercritical carbon dioxide • These coating alternatives can reduce emissions of VOCs and,

in so doing, reduce the generation of hazardous wastes and decrease worker exposure to toxic air emissions

Waterborne CoatingsGeneral Description

The term waterborne refers to coating systems that primarily use water as the solvent to disperse the resin . Usually, they contain up to 80% water with small amounts of other solvents, such as glycol ethers .Most regulations require waterborne coatings to have a VOC content of less than 3.5 pounds per gallon less water .

TechnologyPollution Prevention

BenefitsReported Application Operational Benefits Limitations

Waterborne Eliminates or reduces

solvent in coating (little or no VOC)

Uses water for cleanup

Wide range Architectural trade

finishes Wood furniture Damp concrete

Can apply thick or thin coat

Has easy color blending or changing

Is compatible with conventional and electrostatic application equipment

Has coating flow properties and drying rates that can change with humidity, affecting coating application

Is sensitive to humidity; workplace humidity control required

May have poor flow characteristics due to high surface tension of water

Needs special equipment for electrostatic application

Has water in paint that can cause corrosion of storage tanks and transfer piping, and "flash rusting" of metal substrates

WaterborneCoating

Advantages and Disadvantages of Waterborne Coatings

Advantages Disadvantages

Reduces VOC and HAP emissions Can use conventional application processes Reduces toxicity and odor, resulting in improved worker safety and comfort Has good storage life Is easy to clean up Minimizes or eliminates disposal of hazardous waste Has good to excellent surface properties, including gloss, rub resistance, anti-sealing effects and non-yellowing film Can recover and reuse some waterborne paints, increasing transfer efficiency Some dried waterborne paint waste may be disposed of in a landfill as non-hazardous waste

Has tendency to foam Requires clean surface for high quality application; surface must be free of oil and dust Requires longer drying times or increased oven temperatures Has difficulty obtaining high gloss finish Has difficult cleanup once coating is cured Has higher cost per gallon on an equivalent solids basis compared with conventional coating Does not have many resins available for waterborne formulations Is complex to convert solvent-borne coating line, i.e., stainless steel, plastic lines, valves and other ancillary equipment are needed Has problems with atomization, i.e., reduces paint transfer efficiencies Increases runs and sags Requires good temperature/humidity control Requires storage area enclosure and heating (i.e., repeated freezing and thawing will damage the coating) Is difficult to refinish Has reduced temperature resistance Can have poor penetration and adhesion properties, particularly with emulsion coatings on porous surfaces

Annual Operating Cost Comparison for Waterborne Paint Application and Solvent Based Paint Application

  Waterborne Paint Solvent-Based Paint

Operational Costs:    

Paint: $31,200 $31,200

Solvent: $0 $780

Process Water: $1 $0

Wastewater Disposal: $2 $0

Waste Paint/ Solvent Disposal:

$0 $1,250

Total Operational Costs:

$31,203 $33,230

Total Recovered Income:

$0 $0

Net Annual Cost/Benefit:

-$31,203 -$33,230

Economic Analysis Summary: Annual Savings for Waterborne Paint Application: $2,027Capital Cost for Diversion Equipment/Process: $0Payback Period for Investment in Equipment/Process: Immediate

Types of Waterborne Coatings

• Waterborne coatings are classified based on how the resin is fluidized . The three main types are:

water-soluble/water-reducible (solutions), water-dispersible/colloidal (dispersions) Waterborne Two-Component and emulsions (latex) paints (the most commonly used

form) .• Within each category, physical properties and

performance depend on which resins are used.

Water-soluble paints

• Water-soluble paints are paints whose individual molecules of water-soluble resins dissolve completely in water.

• Water-soluble resins are generally produced via polycondensation or polymerization reactions in an organic medium.

• As a result, they generally contain organic co-solvents like alcohols, glycol ethers or other oxygen-containing solvents that are soluble or miscible with water (organic content less than 10 to 15%).

• Despite their sensitivity to water, water-soluble paints have a high gloss and a high level of corrosion protection, along with good pigment, wetting and stabilization

Water-dispersible paints

• Water-dispersible paints, or colloidal coatings, are paints that have small clusters of insoluble resin particles that are suspended in water. Mechanical agitation is sufficient to suspend the clusters .

• Small amounts of organic solvents (usually less than 5% by weight) are used as coalescing agents that evaporate on drying.

• Resins used in dispersion paints include vinyl acetate copolymers, vinyl propionate copolymers, acrylate-methacrylate copolymers, & styrene-butadiene copolymers and polymers . Colloidal dispersions are used mainly to coat porous materials such as paper or leather .

Waterborne Two-Component

• With this new technology, coatings manufacturers can formulate high-performance coatings without cosolvents and achieve the same appearance, properties and ease of use that manufacturers have with the solvent-borne analogs. For example, an epoxy curing agent for water-based epoxy coating formulations has been designed for use with solid epoxy dispersions. This epoxy curing agent provides corrosion resistance when used as a primer in general metal applications.

Latex paints

• Emulsions, or as they are more commonly known, latex paints, are similar to water-dispersibles. However, resin clusters in emulsions tend to be larger, and an emulsifier is required to keep the clusters in suspension .

• Emulsion paints are manufactured using a variety of resins including styrene-butadiene copolymers, polyvinyl acetate (the most common), acrylics, alkyds and polystyrene. Emulsion paints are widely used in the architectural market segment . The increased permeability of latex paints allows these coatings to "breathe," reducing the chances for blistering or peeling.

Binders for Water borne paint

• Almost all types of resins are available in a waterborne version, including

vinyls, two-component acrylics, epoxies, polyesters, styrene-butadiene, amine-solubilized, carboxyl-terminated alkyd and urethanes

Driers forWater-Borne Coatings

• Hydro-Cure® And Hydro-Cem® Driers are water-reducible driers were developed while working with major water-reducible resin manufacturers. These water-reducible driers represent a major innovation in driers for water-dispersible systems, overcoming the problems encountered with earlier water dispersible driers or conventional driers when used in aqueous systems HYDROCURE and HYDRO-CEM driers include:   • 5% COBALT HYDRO-CURE   • 5% COBALT HYDRO-CURE II   • 5% MANGANESE HYDRO-CURE   • 8% MANGANESE HYDRO-CURE II   • 9% MANGANESE HYDRO-CURE III   • 5% CALCIUM HYDRO-CEM   • 12% ZIRCONIUM HYDRO-CEM   • 10% CERIUM HYDRO-CEM   • 8% ZINC HYDRO-NAP   • 14% BISMUTH HYDRO-NAP

Formation of Emulsions1)Rapid Stirring of two liquid

2)By surface active agents (surfactants)

HLB

Emulsion Paints

• Vinyl emulsion paints

• Acrylic emulsion paints

Vinyle emulsion paint

Acrylic emulsion paint

Patent list

• PAT. NO. Title • 1 6,987,135 Photoactivatable water borne coating composition • 2 6,716,909 Water-borne coating composition and method of forming multilayer coating film • 3 6,627,316 Resin composition for water borne coatings and water borne coating composition • 4 6,420,474 Stain resistant water-borne coating composition • 5 6,248,819 Thermosetting water-borne coating composition, method of forming a coating film using same,

and method of forming a multilayer coating film • 6 6,106,896 Process for applying a water-borne coating to a substrate with compressed fluids • 7 6,034,160 Method for the preparation of water-borne coating compositions using thermoplastic

polyhydroxyether resins having narrow polydispersity • 8 5,760,128 Process for the production of a multi-layer finish and a water-borne coating • 9 5,574,079 Method for the preparation of water-borne coating compositions using thermoplastic

polyhydroxyether resins having narrow polydispersity • 10 5,376,704 Water-borne coating compositions comprising half esters of anhydride polymers crosslinked

by epoxies • 11 5,057,156 Metallic pigment composition and water borne coating composition thereof • 12 5,017,673 Nonionically stabilized polyester urethane resin for water-borne coating compositions • 13 4,981,901 Water-borne coating composition • 14 4,939,189 Water-borne coating composition • 15 4,423,165 Water-borne coating composition made from epoxy resin, first polymeric acid, tertiary amine

and second polymeric acid • 16 4,303,488 Electrocoating with water-borne coating composition made from epoxy resin, polymeric acid

and tertiary amine • 17 4,302,373 Water-borne coating composition made from modified epoxy resin, polymeric acid and

tertiary amine • 18 4,289,826 Water-borne coating for metal surfaces • 19 4,247,439 Water-borne coating composition made from epoxy resin, polymeric acid and tertiary amine • 20 4,233,197 Water-borne coating for metal surfaces

The Manufacture of Water-Borne Coatings.

• Production of paints usually in tree step:

• Wetting• 10%Pigment+1% Binder +3%Solvent

• Dispersion• 1%Binder +3%Solvent

• Mixing• 29%Binder +51%Solvent+1.5%Additives

Roll mill

Figure 22-18 Applied loads on a mixer shaft due to fluid forces.

Torque

Thrust

Bending

Shaft Vibration

Fluid Forces

Appliedloads

Ref: Handbook of Industrial Mixing: Science and Practice

By North American Mixing Forum Publisher:   Wiley-Interscience Number Of Publication Date:   2003-11-21

Figure 22-11 High-shear impeller: used when a fine dispersion is required: Np = 0.45.

Ref: Handbook of Industrial Mixing: Science and Practice

High shear disperser

Mixes paints completely utilizing three axis of motion, including orbital, side-to-side, and up/down

To achieve these multiple motions, the portable shaker spins and eccentric weight rather than using crankshafts, Light weight, only 24 lbs. Portable. 115 Volt motor

Blair 51000 - Paint Shaker Tornado II

Operation in paint Mixing

Waterborne coatings Applications

1-Car Painting:In the past twenty years, environmental and occupational safety concerns have put great pressure on the oil-based coatings industry. Many industries have seen the migration of coatings toward water-based formulations. These changes moved approximately 20% world's automotive industry to water borne coating by 1999. Since this change, there has been a lot of talk about the durability of these automotive paints.For Auto Manufactures such as Daimler/Chrysler Corporation, General Motors and BMW, the advantages for moving to water borne finishes are aimed at reducing VOC emissions during application, waterborne coatings also reduce risk of fire, are easier to clean up (creating less hazardous residues) and result in reduced worker exposure to organic vapors.

Retro-fitted air movement devices for curing and drying

Place in 4 corners of spray booth

3-Artist paint

2-Trafic paints

4-metal coating (water borne anti corresive primer

Refrence

• 1)W.M.MORGANS,OUTLINES OF PAINT TECHNOLOGY, Third edition

G.P.A. TURNER.Introduction to paint chemistry,

• 2)Handbook of industrial mixing

• 3) ( دكتر ( ترجمه رنگ تكنولوژي اصول رنگ شيمي بر اي مقدمه . آروين نشر آگاه هميرا و ترپوگوسيان

• عليرضا . ....(4 ترجمه تاليفو رنگ تجربي شيمياميركبير . انتشارات عظيمي

• 5) هاويلوكس رنگسازي كاتالوگهايشركت

اينترنتي.. منابع :و

• 5) WWW.USPTO.GOV

• 6)http://ep.espacenet.com

TANKS!