Modern Plastics Handbook 2011 Part 13 pptx

Electrical properties Physical characteristics -cm strength, Dielectric Dissipation service temp- Adhesion higher number Abrasion Coating type ASTM D 257 V/mil constant factor erature, °

Electrical properties Physical characteristics

-cm strength, Dielectric Dissipation service temp- Adhesion (higher number Abrasion Coating type (ASTM D 257) V/mil constant factor erature, °F to metals Flexibility is harder) resistance

Acrylic 10 14 –10 15 450–550 2.7–3.5 0.02–0.06 180 Good Good 12–24 Fair

Alkyd 10 14 300–350 4.5–5.0 0.003–0.06 200 Excellent Fair to good 3–13 (air dry) Fair

250 TS Low temperature—poor 10–24 (bake) Cellulosic

Low temperature—poor Chlorinated polyether

Epoxy-amine cure 10 14 at 30°C 400–550 3.5–5.0 0.02–0.03 at 30°C 350 Excellent Fair to good 26–36 Good to excellent

Epoxy-anhydride, dicy 650–730 3.4–3.8 0.01–0.03 400 Excellent Good to excellent 20 Good to excellent

Low temperature—poor Epoxy-polyamide 10 14 at 30°C 400–500 2.5–3.0 0.008–0.02 350 Excellent Good to excellent 20 Fair to good

Low temperature—fair Fluorocarbon TFE 10 18 430 2.0–2.1 0.0002 500 Can be excellent;

primers required Excellent

CTFE 10 18 500–600 2.3–2.8 0.003–0.004 400 Can be excellent;

primers required Excellent Parylene

(polyxylylenes) 10 16 –10 17 700 2.6–3.1 0.0002–0.02 240°F (air) Good Good

510°F (inert sphere) Phenolics 10 9 –10 12 100–300 4–8 0.005–0.5 350 Excellent Poor to good 30–38 Fair

atmo-Low temperature—poor

TABLE 10.6 Properties of Coatings by Polymer Type

Phenolic-oil varnish 250 Excellent Good Poor to fair

Low temperature—fair Phenoxy 10 13 –10 14 500 3.7–4.0 0.001 180 Excellent Excellent

Polyamide (nylon) 10 13 –10 15 400–500 2.8–3.6 0.01–0.1 225–250 Excellent

Polyester 10 12 –10 14 500 3.3–8.1 0.008–0.04 200 Good on rough surfaces; Fair to excellent 25–30 Good

poor to polished metals Chlorosulfonated 6–10 0.03–0.07 250 Good Elastomeric Less than 10

(polyethylene Hypalon)†

400 Polyimide 10 16 –10 18 3000 (10 mil) 3.4–3.8 0.003 500 Good Fair to excellent Good

Polystyrene 10 10 –10 19 500–700 2.4–2.6 0.0001–0.0005 140–180 Poor to fair

Polyurethane 10 12 –10 13 450–500 6.8 (1 kHz) 0.02–0.08 250 Often poor to metals Good to excellent 10–17 (castor oil)

3800 (1 mil) 4.4 (1 MHz) (excellent to most Low temperature—poor 50–60 (polyester)

nonmetals) Silicone 10 14 –10 16 550 3.0–4.2 0.001–0.008 500 Varies, but usually needs Excellent 12–16 Fair to

primer for good adhesion Low temperature—excellent excellent Vinyl chloride (poly-) 10 11 –10 15 300–800 3–9 0.04–0.14 150 Excellent, if so formulated Excellent 5–10

Low temperature—fair to good Vinyl chloride 10 9 –10 16 400 2.3–9 0.10–0.15 150 Requires adhesive primer Excellent 3–6

Vinyl fluoride 10 13 –10 14 260 6.4–8.4 0.05–0.15 300 Excellent, if fused Excellent

1200 (8 mil) on surface Low temperature—excellent Vinyl formal

(Formvar‡) 10 13 –10 15 850–1000 3.7 0.007–0.2 200 Excellent

*Trademark of Hercules Powder Co., Inc., Wilmington, Del.

†Trademark of E I du Pont de Nemours & Co., Wilmington, Del.

‡Trademark of Monsanto Co., St Louis, Mo.

Electrical properties Physical characteristics

-cm strength, Dielectric Dissipation service temp- Adhesion (higher number Abrasion Coating type (ASTM D 257) V/mil constant factor erature, °F to metals Flexibility is harder) resistance

TABLE 10.6 Properties of Coatings by Polymer Type (Continued)

Chemical and humidity to micro- Flamma- Method Cure Application Coating type solvent resistance resistance Weatherability organisms bility Repairability of cure schedule method Typical uses

Acrylic Good Excellent Good Medium Remove with Solvent Air dry or low- Spray, Coatings for circuit boards

resistance to solvent evaporation temperature bake brush, dip Quick dry protection

Alkyd Solvents—poor Poor Good to Poor Medium Poor Oxidation Air dry or Most common Painting of metal

Alkalies—poor excellent or heat baking types methods parts and hardware.

Dilute acids—

poor to fair Cellulosic Solvents—good Fair Poor to good High Remove Solvent Air dry or low- Spray, dip Lacquers for decoration

(nitrate Alkalies—good with solvents evaporation temperature bake and protection Hot-metal

Chlorinate Good Low Powder or High-temperature Spray, dip, Chemically resistant

Epoxy- Solvents—good to Good Pigmented— Good Medium No Cured by Air dry to Spray, dip, Coatings for circuit boards.

amine cure excellent fair; clear—poor catalyst medium bake fluid bed Corrosion-protective

Dilute acids—fair Epoxy- Solvents—good Good Good Medium No Cured by High bakes Spray, dip, fluid High-bake, high-temperature-

anhydride, Alkalies— chemical 300 to 400°F bed, impregnate resistant dielectric and

Epoxy- Solvents—fair Good Good Medium No Cured by Air dry or Spray, dip Coatings for

Epoxy- Solvents—excellent Excellent Pigmented— Good Medium No Cured by High bakes Spray, dip High-bake solvent

phenolic Alkalies—fair fair; clear—poor coreactant 300 to 400°F and chemical

Fluorocarbon Solvents—excellent Excellent Good None No Fusion from Approximately Spray, dip High-temperature

FEP Excellent Good None No Fusion from 500–600°F Spray, dip High-temperature-resistant

solvent dispersion Parylene Excellent None Vapor phase deposition and Very thin, pinhole-free

license from Union Carbide semiconductable coating.

Phenolics Solvents— Excellent Fair Poor to good Medium No Cured by heat Bake 350–500°F Spray, dip High-bake chemical and

Alkalies—poor Dilute acids—good

to excellent

Phenolic-oil varnish Solvents—poor Good Good Poor, Medium Poor Oxidation Spray, brush, dip- Impregnation of electronic

Alkalies—poor unless or heat impregnate modules, quick protective

solderable Polyester Solvents—poor Fair Very good Good Medium Poor Cured by heat Air dry or bake Spray, brush, dip

poor to fair

Dilute acids—good

Chlorosul- Good Good Low Solvent Air dry or low- Spray, brush Moisture and fungus

polyethylene

(Hypalon†)

Polyimide Solvents—excellent Good Good Good Low Poor Cured by heat High bake Dip, impregnate, Very high temperature

fair

Dilute acids—good

Polystyrene Good Good High Dissolve Solvent Spray, dip Coil coating, low

with solvents evaporation Air dry or low bake dielectric constant,

low loss in radar uses.

Polyurethane Solvents—good Good Poor to good Medium Excellent; melts, Coreactant or Air dry to Spray, brush, dip Conformal coating of

Dilute alkalies—fair solder-through moisture cure medium bake circuitry, solderable

Silicone Solvents—poor Excellent Excellent Good Very low Fair to excellent Cured by heat Air dry (RTV) Spray, brush, dip Heat-resistant coating for

Alkalies—good (except Cut and peel or catalyst to high bakes electronic circuitry

Dilute acids—good

Vinyl chloride (poly-) Solvents—alcohol, Good Pigmented— Poor to good Very low Dissolve Solvent Air dry or elevated Spray, dip, Wire insulation Metal

good fair to good (depends on with solvents evaporation temperature roller coat protection (especially

Vinyl chloride Good Poor to good Low Poor Fusion of Bake 250–350°F Spray, dip, Soft-to-hard thick coatings,

(plastisol, (depends on liquid to gel reverse roll electroplating racks,

Vinyl fluoride Good Excellent Good Very low Poor Fusion from Bake 400–500°F Spray, roller coat Coatings for circuitry

solvent Long-life exterior finish.

dispersion Vinyl formal Good Good Medium Poor Cured by heat Bake 300–500°F Roller coat, Wire insulation

coil impregnation.

*Trademark of Hercules Powder Co., Inc., Wilmington, Del.

†Trademark of E I du Pont de Nemours & Co., Wilmington, Del.

‡Trademark of Monsanto Co., St Louis, Mo.

SOURCE: This table has been reprinted from Machine Design, May 25, 1967 Copyright, 1967, by The Penton Publishing Company, Cleveland, Ohio.

Moisture

Chemical and humidity to micro- Flamma- Method Cure Application Coating type solvent resistance resistance Weatherability organisms bility Repairability of cure schedule method Typical uses

ties of the generic resin, can be greatly disappointed Instead, selectionsmust be made on the basis of performance data for specific coatings orfinish systems Performance data are generated by the paint and prod-uct manufacturing industries when conducting standard paint evalua-tion tests Test methods for coating material evaluation are listed inTable 10.7.

10.4.4 Selection by electrical properties

Electrical properties of organic coatings vary by resin (also referred to

as polymer) type When selecting insulating varnishes, insulatingenamels, and magnet wire enamels, the electrical properties and phys-ical properties determine the choice

Table 10.8 shows electric strengths, Table 10.9 shows volume tivities, Table 10.10 shows dielectric constants, and Table 10.11 showsdissipation factors for coatings using most of the available resins.Magnet wire insulation is an important use for organic coatings.National Electrical Manufacturer’s Association (NEMA) standardsand manufacturers’ trade names for various wire enamels are shown

resis-in Table 10.12 This resis-information can be used to guide the selection ofcoatings However, it is important to remember the aforementionedwarnings about blends of various resins and the effects on perfor-mance properties

10.5 Coating Materials

Since it is the resin in the coating’s vehicle that determines its mance properties, coatings can be classified by their resin types Themost widely used resins for manufacturing modern coatings areacrylics, alkyds, epoxies, polyesters, polyurethanes, and vinyls.3In thefollowing section, the resins used in coatings are described

perfor-10.5.1 Common coating resins

Acrylics. Acrylics are noted for color and gloss retention in outdoorexposure Acrylics are supplied as solvent-containing, high-solids,waterborne, and powder coatings They are formulated as lacquers,enamels, and emulsions Lacquers and baking enamels are used asautomotive and appliance finishes Both these industries use acrylics

as topcoats for multicoat finish systems Thermosetting acrylics havereplaced alkyds in applications requiring greater mar resistance such

as appliance finishes Acrylic lacquers are brittle and therefore havepoor impact resistance, but their outstanding weather resistanceallowed them to replace nitrocellulose lacquers in automotive finishes

TABLE 10.7 Specific Test Methods for Coatings

Federal STD MIL-STD- Federal STD

6161.1 (Outdoor Rack)

D 1310 4294 (Cleveland Open Cup) (Tag Open Cup)

D522 6222 (Conical Mandrel)

Test ASTM 141a, method 202, method 406, method Others

MIL-STD-810, 508.1 MIL-T-5422, 4.8

D 1474 6212 (Indentation) Heat resistance D 115

Condensation) Impact resistance D2794 6226 (G E Impact) 1074

MIL-T-5422, 4.1 MIL-STD-810, 504.1

(Cenco Fitch)

C 177 (Guarded Hot Plate)

Thermal shock 107 MIL-E-5272, 4.3

MIL-STD-810, 503.1 Thickness (dry film) D 1005 6181 (Magnetic Gage) 2111, 2121, Fed Std 151, 520, 521.1

Note: A more complete compilation of test methods is found in J J Licari, Plastic Coatings for

Electronics, McGraw-Hill, New York, 1970.

The major collection of complete test methods for coatings is Physical and Chemical Examination of

Paints, Varnishes, Lacquers, and Colors, by Gardner and Sward, Gardner Laboratory, Bethesda, Md This

has gone through many editions.

TABLE 10.7 Specific Test Methods for Coatings (Continued )

Federal STD MIL-STD- Federal STD

Dielectric strength,

Polymer coatings:

350–400 Step-by-step method a

1700–2500 2-mil-thick samples Columbia Technical

Corporation, Humiseal Coatings

Chlorinated polyether 400 Short-time method a

Chlorosulfonated polyethylene 500 Short-time method a

Diallyl isophthalate 422 Step-by-step method a

Depolymerized rubber (DPR) 360–380 H V Hardman Company,

DPR Subsidiary Epoxy 650–730 Cured with anhydride–castor Autonetics, Division of North

oil adduct American Rockwell

Epoxies, modified 1200–2000 2-mil-thick sample Columbia Technical

Corporation, Humiseal Coatings

560 Short-time method, 80 mils thick

400–600 Step-by-step method a

450 60-mil-thick sample c

(single component)

(two components)/castor

oil cured

Polyurethane 275 125-mil-thick sample Products Research &

Polyvinylidene fluoride 260 Short-time, 500-V/s, 1  8 -in sample h

1280 Short-time, 500-V/s, 8-mil sample h

950 Step by step (1-kV steps) h

Polyxylylenes:

Parylene N 6000 Step by step Union Carbide Corporation

6500 Short time Union Carbide Corporation

1200 Step by step Union Carbide Corporation

4500 Step by step Union Carbide Corporation

Silicone 550–650 RTV types General Electric & Stauffer

Chemical Company bulletins Silicone 800 Flexible dielectric gel Dow Corning Corporation Silicone 1500 2-mil-thick sample Columbia Technical

Corporation, Humiseal 1H34 TFE fluorocarbons 400 60-mil-thick sample c

Teflon TFE dispersion coating 3000–4500 1- to 4-mil-thick sample E I du Pont de Nemours &

Company Teflon FEP dispersion coating 4000 1.5-mil-thick sample E I du Pont de Nemours &

Company

for many years Acrylic and modified acrylic emulsions have been used

as architectural coatings and also on industrial products These um-priced resins can be formulated to have excellent hardness, adhe-sion, abrasion, chemical, and mar resistance When acrylic resins areused to modify other resins, their properties are often imparted to theresultant resin system

medi-Uses. Acrylics, both lacquers and enamels, were the topcoats of choicefor the automotive industry from the early 1960s to the middle 1980s.Thermosetting acrylics are still used by the major appliance industry.Acrylics are used in electrodeposition and have largely replacedalkyds The chemistry of acrylic-based resins allows them to be used inradiation curing applications alone or as monomeric modifiers for oth-

er resins Acrylic-modified polyurethane coatings have excellent rior durability

exte-Alkyds. Alkyd resin–based coatings were introduced in the 1930s asreplacements for nitrocellulose lacquers and oleoresinous coatings.They offer the advantage of good durability at relatively low cost.These low- to medium-priced coatings are still used for finishing awide variety of products, either alone or modified with oils or otherresins The degree and type of modification determine their perfor-mance properties They were used extensively by the automotive andappliance industries through the 1960s Although alkyds are used inoutdoor applications, they are not as durable in long-term exposure,and their color and gloss retention is inferior to that of acrylics

Uses. Once the mainstay of organic coatings, alkyds are still used forfinishing metal and wood products Their durability in interior expo-sures is generally good, but their exterior durability is only fair Alkydresins are used in fillers, sealers, and caulks for wood finishing

Coatings and Finishes 10.23

Dielectric strength,

*All samples are standard 125 mils thick unless otherwise specified.

a Insulation, Directory Encyclopedia Issue, no 7, June–July 1968.

b Material Engineering, Materials Selector Issue, vol 66, no 5, Chapman-Reinhold Publication, mid-October 1967–1968.

c W H Kohl, Handbook of Materials and Techniques for Vacuum Devices, p 586, Reinhold Publishing Corporation, New York,

1967, p 586.

d J R Learn and M P Seegers, “Teflon-Pyre-M L Wire Insulation System,” 13th Symposium on Technical Progress in Commun Wire and Cables, Atlantic City, NJ, December 2–4, 1964.

e J T Milek: Polyimide Plastics: A State of the Art Report, Hughes Aircraft Report, S-8, October, 1965.

f Hughson Chemical Co Bulletin 7030A.

g Spencer-Kellogg (Division of Textron, Inc.) Bulletin TS-6593.

h Pennsalt Chemicals Corp Prod Sheet KI-66a, Kynar Vinylidene Fluoride Resin, 1967.

TABLE 10.8 Electric Strengths of Coatings (Continued)

TABLE 10.9 Volume Resistivities of Coatings

832, & 833

Corporation Humiseal 1H34

a Materials Engineering, Materials Selector Issue, vol 66, no 5, Chapman-Reinhold

Publication, mid-October 1967–1968.

b Insulation, Directory Encyclopedia Issue, no 7, June–July 1968.

c H Lee and K Neville, Epoxy Resins, McGraw-Hill, New York, 1966.

d Tucker, Cooperman, and Franklin, Dielectric Properties of Casting Resins, Electronics

Equipment, July 1956.

e J H Freeman, “A New Concept in Flat Cable Systems,” 5th Annual Symposium on Advanced

Technology for Aircraft Electrical Systems, Washington, D.C., October 1964.

f J T Milek, “Polyimide Plastics: A State of the Art Report,” Hughes Aircraft Rep S-8, October

1965.

g L Hockenberger, Chem.-Ing Tech., vol 36, 1964.

h Hughson Chemical Company Technical Bulletin 7030A; Pennsalt Chemicals Corporation Product Sheet KI-66a, Kynar Vinylidene Fluoride Resin, 1967.

Coatings and Finishes 10.25

TABLE 10.10 Dielectric Constants of Coatings

Rockwell

TABLE 10.10 Dielectric Constants of Coatings (Continued)

castor oil cured)

(two components) Chemical Corporation (PR-1538)

Corporation

dielectric gel Corporation

de Nemours & Company

de Nemours & Company

*Trademark of General Mills, Inc., Kankakee, Ill.

†Trademark of E I du Pont de Nemours & Company, Wilmington, Del.

‡Trademark of Dow Corning Corporation, Midland, Mich.

a Materials Engineering, Materials Selector Issue, vol 66, no 5, Chapman-Reinhold Publication,

mid-October 1967–1968.

b M C Volk, J W Lefforge, and R Stetson, Electrical Encapsulation, Reinhold Publishing

Corporation, New York, 1962.

c Insulation, Directory Encyclopedia Issue, no 7, June–July 1968.

d C F Coombs, ed., Printed Circuits Handbook, McGraw-Hill, New York, 1967.

e H Lee and K Neville, Handbook of Epoxy Resins, McGraw-Hill, New York, 1967.

f J R Learn and M P Seeger, Teflon-Pyre-M.L Wire Insulation System, 13th Symposium

of Technical Progress in Communications Wire and Cable, Atlantic City, NJ, Dec 2–4, 1964.

g Du Pont Bulletin H65-4, Experimental Polyimide Insulating Varnishes, RC-B-24951 and

RC-5060, January 1965.

h L Hockenberger, Chem.-Ing Tech vol 36, 1964.

i Spencer-Kellogg (division of Textron, Inc.) Bull TS-6593.

jW S Barnhart, R A Ferren, and H Iserson, 17th ANTEC of SPE, January 1961.

k Pennsalt Chemicals Corporation Product Sheet KI-66a, Kynar

Vinylidene Fluoride Resin, 1967.

l A R Von Hippel, ed., Dielectric Materials and Applications, Technology Press of MIT and

John Wiley & Sons, Inc., New York, 1961.

TABLE 10.11 Dissipation Factors of Coatings

versamid 125, 60% epoxy)

Versamid 115, 50% epoxy)

Epoxy cured with anhydride– 0.0084 0.0165 0.0240 Autonetics, North American Rockwell

castor oil adduct

Polyurethane (two component, 0.016–0.036

castor oil cure)

Polyurethane (one component) 0.038–0.039 0.068–0.074 Conap Inc.

Coating 60–100 Hz 10 Hz 10 Hz Reference source

Polyxylylenes:

Teflon FEP dispersion coating 0.0002–0.0007 E I du Pont de Nemours & Company

a Machine Design, Plastics Reference Issue, vol 38, no 14, Penton Publishing Co., 1966.

b Insulation, Directory, Encyclopedia Issue, no 7, June–July 1968.

c H Lee and K Neville, Handbook of Epoxy Resins, McGraw-Hill, New York, 1967.

dK Mathes, Electrical Insulation Conference, 1967.

e Spencer-Kellogg (Division of Textron, Inc.) Technical Bulletin TS-6593.

fW S Barnhart, R A Ferren, and H Iserson, 17th ANTEC of SPE, January 1961.

g Pennsalt Chemicals Corporation Product Sheet KI-66a, Kynar Vinylidene Fluoride Resin, 1967.

h Machine Design, Design Guide, September 28, 1967.

because of their formulating flexibility Alkyds have also been used inelectrodeposition as replacements for the oleoresinous vehicles Theyare still used for finishing by the machine tool and other industries.Alkyds have also been widely used in architectural and trade salescoatings Alkyd-modified acrylic latex paints are excellent architec-tural finishes.

Epoxies. Epoxy resins can be formulated with a wide range of erties These medium- to high-priced resins are noted for their adhe-sion, make excellent primers, and are used widely in the appliance andautomotive industries Their heat resistance permits them to be usedfor electrical insulation When epoxy top coats are used outdoors, theytend to chalk and discolor because of inherently poor ultraviolet lightresistance Other resins modified with epoxies are used for outdoorexposure as topcoats, and properties of many other resins can beimproved by their addition Two-component epoxy coatings are used inenvironments with extreme corrosion and chemical conditions.Flexibility in formulating two-component epoxy resin–based coatingsresults in a wide range of physical properties

primers for most coatings over most substrates Epoxy coatings vide excellent chemical and corrosion resistance They are used aselectrical insulating coatings because of their high electric strength

pro-at elevpro-ated temperpro-atures Some of the original work with powdercoating was done using epoxy resins, and they are still applied usingthis method Many of the primers used for coil coating are epoxyresin based

Polyesters. Polyesters are used alone or modified with other resins toformulate coatings ranging from clear furniture finishes—replacinglacquers—to industrial finishes—replacing alkyds These moderatelypriced finishes permit the same formulating flexibility as alkyds butare tougher and more weather resistant There are basically two types

of polyesters: two-component and single-package Two-component polyesters are cured using peroxides which initiate free-radical poly- merization, while single-package polyesters, sometimes called oil-free alkyds, are self-curing, usually at elevated temperatures It is impor-

tant to realize that, in both cases, the resin formulator can adjustproperties to meet most exposure conditions Polyesters are alsoapplied as powder coatings

glass-reinforced plastic bathtubs, lavatories, boats, and automobiles.Figure 10.2 shows tub and shower units using a polyester gel coat

Coatings and Finishes 10.29

Polyvinyl Polyvinyl formal Polyvinyl formal with Plain Polyvinyl formal with nylon butyral Manufacturer enamel formal modified overcoat overcoat Polyamide Acrylic Epoxy

Thermal class 105°C 105°C 105°C 105°C 105°C 105°C 105°C 130°C

NEMA Standard* MW 1 MW 15 MW 27 MW 17 MW 19 MW 6 MW 4 MW 9

Anaconda Plain Formvar Hermetic Nyform Cement- ……… ……… Epoxy,

-coated Asco Enamel Formvar ……… Nyform Formbond Nylon Acrylic Epoxy

Wire & Cable

Chicago Plain Formvar ……… Nyform Bondable Nylon Acrylic Epoxy

Wire

Corporation

Essex Wire Plain Formvar Formetex Nyform Bondex ……… Ensolex/ Epoxy

General Plain Formvar Formetic Formlon Formese ……… Solder- Epoxy

Hudson Plain Formvar ……… Nyform Formvar Ezsol ……… ………

Company

Wire & Cable, enamel

Inc.

Phelps Dodge Enamel Formvar Hermeteze Nyform Bondeze ……… ……… ………

Magnet Wire

Corporation

Rea Magnet Plain Formvar Hermetic Nyform Koilset Nylon ……… Epoxy

Viking Wire Enamel Formvar ……… Nyform F-Bondall Nylon ……… ………

Company, Inc.

*National Electrical Manufacturers Association.

SOURCE : Courtesy of Rea Magnet Wire Company, Inc.

Insulation

Coatings and Finishes 10.31

Poly- with friction nylon with butyral and butyral with Poly- Polyester Teflon urethane surface overcoat overcoat overcoat Polyester overcoat imide polyimide silicon

ceramic-200°C 105°C 105°C 130°C 105°C 130°C 155°C 155°C 220°C 180°C 180°C

(PROP) (PROP) ……… Analac ……… Nylac Cement- Cement- ……… Anatherm AL 220 Anatherm

200 ……… Poly ……… Nypol Asco Asco Ascotherm Isotherm ML Anamid M

imide), ……… Beldure ……… Beldsol ……… ……… Isonel Polyther- ML Ascomid

.……… Soderex ……… Soderon Soder- Soder- Thermalex Polyther- Allex

bond bond N F malex/

PTX 200 ……… Enamel “G” ……… Genlon ……… ……… Gentherm Polyther-

maleze 200 ……… ……… ……… ……… ……… ……… Alkanex

Teflon ……… ……… ……… ……… ……… Isonel ………

Temprite

.……… Hudsol Gripon Nypoly Hudsol Nypoly Isonel Isonel ML Isomid

.……… Impsol ……… Impsolon ……… ……… ……… Imp-200 ……… ………

.……… Sodereze Gripeze Nyleze ……… S-Y Polyther- ML

Bondeze maleze

200 II ……… Solvar ……… Nylon Solvar ……… Isonel Polyther- Pyre Isomid Ceroc

.……… Polyure- ……… Polynylon P-Bondall ……… Isonel Iso-poly ML Isomid

High-quality one-package polyester finishes are used on furniture,appliances, automobiles, magnet wire, and industrial products.Polyester powder coatings are used as high-quality finishes in indoorand outdoor applications for anything from tables to trucks They arealso used as coil coatings.

Polyurethanes. Polyurethane resin–based coatings are extremely tile They are higher in price than alkyds but lower than epoxies.Polyurethane resins are available as oil-modified, moisture-curing,blocked, two-component, and lacquers Table 10.13 is a selection guidefor polyurethane coatings Two-component polyurethanes can be formu-lated in a wide range of hardnesses They can be abrasion-resistant,flexible, resilient, tough, chemical-resistant, and weather-resistant.Abrasion resistance of organic coatings is shown in Table 10.14.Polyurethanes can be combined with other resins to reinforce or adopttheir properties Urethane-modified acrylics have excellent outdoorweathering properties They can also be applied as air-drying, forced-dried, and baking liquid finishes as well as powder coatings

trans-portation industry, which includes aircraft, automobiles, railroads,

Figure 10.2 Polyester gel coats are used to give a decorative and protective surface

to tub shower units which are made out of glass fiber–reinforced plastics.

(Courtesy of Owens-Corning Fiberglas Corporation.)

TABLE 10.13 Guide to Selecting Polyurethane Coatings

One-component Property Urethane oil Moisture Blocked Two-component Lacquer

Abrasion Fair–good Excellent Good–excellent Excellent Fair

resistance

Hardness Medium Medium–hard Medium–hard Soft–very hard Soft–medium

Flexibility Fair–good Good–excellent Good Good–excellent Excellent

Weatherability

Cure temp Room temperature Room temperature 300–390°F 212°F 150–225°F

trucks, and ships Owing to their chemical resistance and ease of tamination from chemical, biological, and radiological warfare agents,they are widely used for painting military land vehicles, ships, and air-craft They are used on automobiles as coatings for plastic parts and asclear topcoats in the basecoat–clearcoat finish systems Low-tempera-ture baking polyurethanes are used as mar-resistant finishes for prod-ucts that must be packaged while still warm Polyurethanes are used

decon-in an decon-increasdecon-ing number of applications They are also used decon-in tion curable coatings

radia-Polyvinyl chloride. Polyvinyl chloride (PVC) coatings, commonly called vinyls, are noted for their toughness, chemical resistance, and

durability They are available as solutions, dispersions, and lattices.Properties of vinyl coatings are listed in Table 10.15 They areapplied as lacquers, plastisols, organisols, and lattices PVC coatingpowders have essentially the same properties as liquids PVC organ-isol, plastisol, and powder coatings have limited adhesion and

TABLE 10.14 Abrasion Resistance of Coatings

Taber ware index,

TABLE 10.15 Properties of Vinyl Coatings

Weatheringa

chemical resistance;

tasteless, odorless

abrasion resistance; can

be applied without solvents

excellent color, flexibility;

tasteless, odorless

aE  excellent; G  good; F  fair; P  poor.

bVinyl chloride acetate copolymers; resins vary widely in compatibility with other materials.

cVinyl chloride acetate copolymer and vinyl chloride resins.

dVinyl chloride acetate copolymers; require grinding for good dispersions.

eRequires primer for use on metal.

fPigmented.

require primers.

Uses. Vinyls have been used in various applications, including beverageand other can linings, automobile interiors, and office machine exteriors.They are also used as thick-film liquids and as powder coatings for elec-trical insulation Owing to their excellent chemical resistance, they areused as tank linings and as rack coatings in electroplating shops Typicalapplications for vinyl coatings are shown in Fig 10.3 Vinyl-modifiedacrylic latex trade sale paints are used as trim enamels for exterior appli-cations and as semigloss wall enamels for interior applications

10.5.2 Other coating resins

In addition to the aforementioned materials, there are a number ofother important resins used in formulating coatings These materials,used alone or as modifiers for other resins, provide coating vehicleswith diverse properties

melamine, are used in modifying other resins to increase their bility Notable among these modified resins are the superalkyds used

dura-in automotive and appliance fdura-inishes

for alkyds and other resins to increase hardness and accelerate cure

Figure 10.3 Vinyl plastisols and organisols are used extensively for dip coating of wire

products The coatings can be varied from very hard to very soft (Courtesy of M & T Chemicals.)

Cellulosics. Nitrocellulose lacquers are the most important of the lulosics They were introduced in the 1920s and used as fast-dryingfinishes for a number of manufactured products Applied at low solidsusing expensive solvents, they will not meet air-quality standards Bymodifying nitrocellulose with other resins such as alkyds and ureas,the VOC content can be lowered and performance properties can beincreased Other important cellulosic resins are cellulose acetatebutyrate and ethyl cellulose

industry, nitrocellulose lacquers are still used by the furnitureindustry because of their fast-drying and hand-rubbing properties.Cellulose acetate butyrate has been used for coating metal innumerous applications In 1959 one of the first conveyorized pow-der coating lines in the United States coated distribution trans-former lids and hand-hole covers with a cellulose acetate butyratepowder coating

Chlorinated rubber. Chlorinated rubber coatings are used as ming pool paints and traffic paints

swim-Fluorocarbons. These high-priced coatings require high processingtemperatures and therefore are limited in their usage They are notedfor their lubricity or nonstick properties due to low coefficients of fric-tion, and also for weatherability Table 10.16 gives the coefficients offriction of typical coatings

pro-cessing equipment They are also used as nonstick coatings for ware, friction-reducing coatings for tools, and dry lubricated surfaces

cook-in many other consumer and cook-industrial products, as shown cook-in Fig.10.4 Table 10.17 compares the properties of four fluorocarbons

Oleoresinous. Oleoresinous coatings, based on drying oils such as bean and linseed, are slow curing For many years prior to the introduc-tion of synthetic resins, they were used as the vehicles in most coatings.They still find application alone or as modifiers to other resins

for structural, marine, architectural, and, to a limited extent, trial product finishing

indus-Phenolics. Introduced in the early 1900s, phenolics were the firstcommercial synthetic resins They are available as 100% phenolic bak-ing resins, oil-modified, and phenolic dispersions Phenolic resins,used as modifiers, will improve the heat and chemical resistance of

Coatings and Finishes 10.37

Catalyzed epoxy air-dry

a F P Bowder, Endeavor, vol 16, no 61, 1957, p 5.

bProduct Techniques Incorporated, Bulletin on PT-401 TE, October 17, 1961.

cUnion Carbide data.

d DuPont Technical Bulletin 19, Pyre-ML Wire Enamel, August 1967.

eElectrofilm, Inc data.

Figure 10.4 Nonstick feature of fluorocarbon finishes

makes them useful for products such as saws, fan and

blower blades, door-lock parts, sliding- and folding-door

hardware, skis, and snow shovels (Courtesy of E I Du

Pont de Nemours & Company.)

TABLE 10.17 Properties of Four Fluorocarbons

Polytrifluoro- Polyvinyl-idene chloroethylene fluoroethylene Polyvinyl fluoride fluoride (PVF-2) (PTFC1) (PTFE) Property (PVF) (CH2-CHF)n (CH2-CF2)n (CC1F-CF2)n (CF2- CF2)n

Coefficient of linear expansion 2.8  10 5 8.5  10 5 15  10 5 8  10 5

Electrical properties:

Dielectric strength, V/mil 260 (0.125) 500 (0.063) 600 (0.060)

Short time, V/mil, in 3400 (0.002)

other resins Baked phenolic resin–based coatings are well known fortheir corrosion, chemical, moisture, and heat resistance.

Uses. Phenolic coatings are used on heavy-duty air-handling equipment,chemical equipment, and as insulating varnishes Phenolic resins arealso used as binders for electrical and decorative laminated plastics

Polyamides. One of the more notable polyamide resins is nylon, which

is tough, wear-resistant, and has a relatively low coefficient of friction

It can be applied as a powder coating by fluidized bed, electrostaticspray, or flame spray Table 10.18 compares the properties of threetypes of nylon polymers used in coatings Nylon coatings generallyrequire a primer Polyamide resins are also used as curing agents fortwo-component epoxy resin coatings Film properties can be variedwidely by polyamide selection

toughness and mechanical durability to office furniture Otherpolyamide resins are used as curing agents in two-component epoxyresin–based primers and topcoats, adhesives, and sealants

Polyolefins. These coatings, which can be applied by flame spraying,hot melt, or powder coating methods, have limited usage

TABLE 10.18 Properties of nylon coatings

Uses. Polyethylene is used for impregnating or coating packaging rials such as paper and aluminum foil Certain polyethylene-coatedcomposite packaging materials are virtually moisture-proof Table 10.19compares the moisture vapor transmission rates of various coatings andfilms Polyethylene powder coatings are used on chemical processingand food-handling equipment.

mate-Polyimides. Polyimide coatings have excellent long-term thermal bility, wear, mar and moisture resistance, as well as electrical proper-ties They are high in price

sta-Coatings and Finishes 10.41

TABLE 10.19 Moisture-Vapor Transmission Rates per 24-h Period of Coatings and Films in g/(mil)(in 2 )

(2-mil sample)

(2-mil sample)

*Trademark of Avisun Corporation, Philadelphia, Pa.

†Trademark of E I du Pont de Nemours & Company, Wilmington, Del.

Uses. Polyimide coatings are used in electrical applications as lating varnishes and magnet wire enamels in high-temperature,high-reliability applications They are also used as alternatives tofluorocarbon coatings on cookware, as shown in Fig 10.5.

insu-Silicones. Silicone resins are high in price and are used alone or asmodifiers to upgrade other resins They are noted for their high tem-perature resistance, moisture resistance, and weatherability They can

be hard or elastomeric with baking or room temperature curing

stacks, ovens, and space heaters Figure 10.6 shows silicone coatings

on fireplace equipment They are also used as conformal coatings forprinted wiring boards, moisture repellants for masonry, weather-resis-tant finishes for outdoors, and thermal control coatings for space vehi-cles The thermal conductivities of coatings are listed in Table 10.20

10.6 Application Methods

The selection of an application method is as important as the selection

of the coating itself Basically, the application methods for industrial uid coatings and finishes are dipping, flow coating, and spraying,although some coatings are applied by brushing, rolling, printing, andsilk screening The application methods for powder coatings and finish-

liq-es are fluidized beds, electrostatic fluidized beds, and electrostatic sprayoutfits In these times of environmental awareness, regulation, andcompliance, it is mandatory that coatings be applied in the most effi-cient manner.3 Not only will this help meet the air-quality standards,but it will also reduce material costs The advantages and disadvan-tages of various coating application methods are given in Table 10.21.Liquid spray coating equipment can be classified by its atomizingmethod: air, hydraulic, or centrifugal These can be subclassified intoair atomizing, airless, airless electrostatic, air-assisted airless electro-static, rotating electrostatic disks and bells, and high-volume, low-pressure types While liquid dip coating equipment is usually simple,electrocoating equipment is fairly complex using electrophoresis as thedriving force Other liquid coating methods include flow coating, whichcan be manual or automated, roller coating, curtain coating, and cen-trifugal coating Equipment for applying powder coatings is not asdiversified as for liquid coatings It can only be classified as fluidizedbed, electrostatic fluidized bed, and electrostatic spray

It is important to note that environmental and worker safety lations can be met, hazardous and nonhazardous wastes can bereduced, and money can be saved by using compliance coatings (those

regu-Figure 10.6 Silicone coatings are used as heat-stable

finishes for severe high-temperature applications such

as fireplace equipment, exhaust stacks, thermal

con-trol coatings for spacecraft, and wall and space

heaters (Courtesy of Copper Development Association.)

Figure 10.5 Polyimide coating is used as a protective finish on the

inside of aluminum, stainless steel, and other cookware (Courtesy

of Mirro Aluminum Company.)

TABLE 10.20 Thermal Conductivities of Coatings

Manufacturing, No 5133

and coatings)

Company

Research Company

Coatings and Finishes 10.45

TABLE 10.20 Thermal Conductivities of Coatings (Continued)

k value,*

cal/(s)(cm 2 )

Other materials used in

*All values are at room temperature unless otherwise specified.

†Trademark of Shell Chemical Company, New York, N.Y.

‡Trademark of Driver-Harris Company, Harrison, N.J.

a Materials Engineering, Materials Selector Issue, vol 66, no 5, Chapman-Reinhold

Publication, mid-October 1967.

b D C Wolf, Proceedings, National Electronics and Packaging Symposium, New York,

June 1964.

c H Lee and K Neville, Handbook of Epoxy Resins, McGraw-Hill, New York, 1966.

d R Davis, Reinforced Plastics, October 1962.

e DuPont Technical Bulletin 19, Pyre-ML Wire Enamel, August 1967.

f DuPont Technical Bulletin 1, Pyre-ML Varnish RK-692, April 1966.

g W C Teach and G C Kiessling, Polystyrene, Reinhold Publishing Corporation,

New York, 1960.

hW S Barnhart, R A Ferren, and H Iserson, 17th ANTEC of SPE, January 1961.

i A J Gershman and J R Andreotti, Insulation, September 1967.

j American Lava Corporation Chart 651.

k E B Shand, Glass Engineering Handbook, McGraw-Hill, 1958.

l W D Kingery, “Oxides for High Temperature Applications,” Proceedings, International Symposium, Asilomar, Calif., October 1959, McGraw-Hill, New York, 1960.

m W H Kohl, Handbook of Materials and Techniques for Vacuum Devices, Reinhold

Publishing Company, New York, 1967.

n Modern Plastics Encyclopedia, McGraw-Hill, New York, 1968.

Spray Fast, adaptable to varied

shapes and sizes

Equipment cost is low.

even on complex parts such

as tubes and high-density electronic modules.

good “wetting” of surface, resulting in good adhesion

Cost of equipment is lowest.

process; provides excellent control on thickness.

Impregnation Results in complete coverage

of intricate and closely spaced parts Seals fine leaks or pores.

Fluidized bed Thick coatings can be applied

in one dip Uniform coating thickness on exposed surfaces

Dry materials are used, saving cost of solvents.

Difficult to completely coat complex Motor frames and

Viscosity and pot life of dip must Small- and medium-sized

be monitored Speed of withdrawal parts, castings, moisture must be regulated for consistent and fungus proofing of

of finished machined parts.

Poor thickness control; not for Coating of individual components,

High labor cost.

Large runs of flat sheets or coil Metal decorating of

Equipment cost is high

cycling or both Special equipment field and armature windings,

of porous structures.

Requires preheating of part to Motor stators; heavy-duty electrical

coating This temperature may for circuit boards, heat sinks.

be too high for some parts.

TABLE 10.21 Application Methods for Coatings

Screen-on Deposits coating in selected

areas through a mask

Provides good pattern deposition and controlled thickness.

Electrocoating Provides good control of

thickness and uniformity

Parts wet from cleaning need not be dried before coating.

Vacuum

deposition Ultrathin, pinhole-free films

possible Selective deposition can be made through masks.

Electrostatic Highly efficient coverage and

Limited number of coating types Primers for frames and bodies, complex

be specially formulated ionic polymers

Often porous, sometimes nonadherent.

Thermal instability of most plastics; Experimental at present Potential use is decomposition occurs on products in microelectronics, capacitor dielectrics.

Vacuum control needed

High equipment cost Requires Heat dissipators, electronic enclosures,

TABLE 10.21 Application Methods for Coatings

(Continued)