53741251 Fiberglass Composites Application Guide

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A WORD TO OUR VALUED CUSTOMERS . . .

As your partner in the composites products industry, CCP is committed tosupporting your success by providing the latest in composites technology.

We believe that commitment goes beyond researching, developing, and

making the best products on the market. By publishing this tenth edition o theCCP Composites Application Guide, our technical sta also provides thosecritical how tosthat is, expert advice and inormation to assist you withproduct selection, application techniques, processes, equipment, trouble-shooting, and environmental regulations, as well as other considerations.

Over these ten editions o the Application Guide, the products we makeand the products you makehave seen many changes.

With the implementation o new standards and regulations, you are chal-lenged with making the transition to new processes and new materials. Wewant that experience to be smooth and trouble-ree or you. From low HAP

materials to no-HAP processes, this manual will provide you with detailedinormation on emerging markets and technologies.

Customer satisaction and product quality are the highest priority at CCP. It isour goal to more than meet the expectations o our customers. We hope thismanual will serve you not only as a tool in support o the products you make,but as an important element in our ongoing business relationship.

As always, we welcome your comments and suggestions.

ABOUT CCPS WEBSITE . . .

Please pay a visit to CCPs website, www.ccponline.com, where you will nd a wealth ovaluable inormation, any day, any time. Composites product data sheets and MSDSs areall available in printable PDF ormat. Youll also nd a handy interactive map with contactinormation or product distributors in your area. And, under Whats New, you can trackCCPs participation in industry trade shows, and keep up with other announcements per-tinent to your business operations.

As always, we value your input regarding our website and appreciate your ideas on howwe may make the site even more useul to you. E-mail your comments to [email protected].

2005, Cook Composites and Polymers Co. www.ccponline.com 1
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TABLE OFCONTENTS

Part OneIntroductionA Word About our Company .................................1About CCPs Website ...............................................1Table of Contents .....................................................2CCP Trademarks ......................................................3

Part TwoHealth, Safety, and the Environment .........4

Part ThreeFRP CompositesI Introduction .......................................................... 11

II General Chemistry of FRP Composites Resins ..12III General Properties of FRP Composites Resins...16IV Fabrication of FRP Composites ...........................18

Part FourOpen Molding I Introduction ..........................................................21II Conventional Gel Coat II.1 Materials ....................................................22 II.2 Color ...........................................................24

II.3 Spray Equipment .......................................29 II.4 Application .................................................46 II.5 Troubleshooting Guide...............................51III Specialty Gel Coats III.1 Conductive Sanding...................................61 III.2 Metalflake ..................................................62 III.3 Metallic.......................................................66 III.4 Enamels .....................................................68IV Vinyl Ester Barrier Coats ..................................... 70V Lamination V.1 Laminating Resins .....................................72 V.2 Fiber Reinforcements ................................74

V.3 Catalysts .....................................................76 V.4 Equipment/Application Methods............. 77 V.5 Secondary Bonding...................................84 V.6 Acrylic Bonding..........................................86 V.7 Troubleshooting .........................................89VI Sprayable Print Blockers .....................................92VII Field Service VII.1 Cosmetics...................................................93 VII.2 Weathering .................................................95 VII.3 Cracking.................................................... 105 VII.4 Swimming Pool Recommendations........107 VII.5 Blisters and Boil Tests .............................. 109

VII.6 Patching.....................................................113

Part FiveLow Volume Closed MoldingI Introduction ....................................................... 120

II Materials ............................................................ 121 III Preform Constructions for Closed Molding .... 123 IV Process Features and Variations .................... 125 V Converting from Open Molding ...................... 140

Part SixCompression MoldingI Introduction .......................................................... 151

II Materials/Typical Compound Formulations .....152 III Compounding Processes and Equipment .......155 IV Molding Processes and Equipment ..................157

V Troubleshooting ..................................................159

Part SevenCastingI Introduction .........................................................162

II Cast Polymer .......................................................163 III Solid Surface ........................................................179 IV Flexible Casting Resins ....................................... 181 V Thermal Shock Testing Request .........................184

Part EightPolyester ToolingI Introduction .........................................................187

II The Master Model ..............................................188 III Master Model Preparation ................................189

IV Applying Release Wax .......................................190 V Building a Mold ..................................................192 VI Mold Surface Distortion .....................................200VII Mold Break-In Procedures ................................202VIII Mold Maintenance ............................................204 IX Mold Resurfacing ...............................................205 X Mold Storage ......................................................206 XI Special Precautions ..........................................207

Part NineThermaCleanProducts ......................209

Part TenAppendices I Appendix A: Quality Control Lab/Test Methods 211

II Appendix B: Polyester Resin Bulk Storage ......223 III Appendix C: Definitions of Terms .....................226 IV Appendix D: Painting Polyester Gel Coats ......238 V Appendix E: Additional Information

V.1 Useful Conversion Factors ........................239 V.2 Drums (Stick Measurement) ......................241 V.3 Conversion Table/Materials Coverage ...242 V.4 Comparison of Sizes .................................243 V.5 Temperature Conversion Table ................244 V.6 Record of Current Products ......................245 V.7 Gel Coat Spray Test Sheet .........................246 V.8 Mixing......................................................... 247

V.9 Catalyst Levels ...........................................248 V.10 Application Helpful Hints..........................249 V.11 Wet-to-Cured .............................................250 V.12 Service Kit Items..........................................251 V.13 Equipment Maintenance/Cleanup..........252 V.14 Catalyst Precautions .................................253

Contact Information ..................................................254

Inside Back Cover Partners in Composites Warranty, Disclaimer, and Limitation of Liability

2 www.ccponline.com 2005, Cook Composites and Polymers Co.
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CCP TRADEMARKS

ACPOLacrylic modied polymers.

AQUACLEANmachine-designed or cleaning tools usedin composite parts manuacturing.

AQUAWASHwater-based resin emulsier cleaner.

ArmorCastcasting resins designed or a wide variety ocasting applications.

ArmorClearlower emission gel coat with improved fex-ibility and good weathering resistance.

ARMORCOTEin-mold coating with durability that ar ex-

ceeds basic gel coat.ArmorFlexgel coat with improved fexibility over stan-dard gel coats.

ArmorGuardvinyl ester barrier coat designed or reduc-ing osmotic blistering.

ArmorShield PBsyntactic oam designed to reduce -ber print in a bulk laminate.

ArmorStarepoxy-modied skin and bulk-laminatingresins designed or the marine industry.

BUFFBACKgel coat with excellent gloss recovery in therepair process.

EASYCLEANmachine designed or cleaning tools usedin composites parts manuacturing.

MARBLECLEANcleaning machine or cultured marble

and solid surace.MARBLEWASHnon-hazardous solvent-based cleaneror use in MARBLECLEAN machine.

NUPOLthermosetting acrylic resin.

OPTIMOLDmold construction system that includes alled tooling resin mix or rapid mold production.

OptiPLUSmold construction system or non-lled shrinkcontrolled tooling resin.

PATCHAIDadditive designed or gel coat and in-mold

coating to improve patching results.POLYCORproducts o UPR, gel coats, and polymer sys-tems.

REPLACETONEwater-based resin emulsier.

STYPOLproducts o UPR, gel coats, and polymer sys-tems.

THERMACLEANnon-hazardous cleaning products.

UNISOLVEuniversal solvent.

UNIWIPElow NVR surace cleaner.

Wipe-Brightsurace cleaner.

XYCONamily o hybrid polymers based on polyester(or other unsaturated polymers) and urethane chemistries;also considered an inter-penetrating polymers network.

Listed below are trademarked CCP products designed spe-cically or the composites market. The CCP logo and trade-

marked product name assure optimum quality backed by atradition o commitment to research.


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HEALTH, SAFETY, and the ENVIRONMENT


1. INTRODUCTIONHealth, saety and the environmentare o prime importance to all manuacturers, especiallythose handling hazardous materials and chemicals. Thishas become a very complex issue with numerous Federal,

State and Local regulations. Each user o a chemical prod-uct, such as polyester resin and gel coat, must comply withFederal, State and Local laws that regulate production, em-ployee exposure, emissions, and shipping hazardous ma-terials and waste.

The ollowing inormation is o a general nature only. Com-pliance requirements must be determined by the user o theproduct. Inormation concerning the hazards o these prod-ucts can be ound in the Material Saety Data Sheet (MSDS)and label or each product. These documents must be read.Polyester resins and gel coats can be handled saely whenproper precautions are taken to protect workers, acilities,and the environment.

CCP products are intended or industrial users only. Salesto private individuals and home consumers is not recom-mended nor endorsed. CCP does not sell products (norrecommend that they be sold) to private individuals or re-pairing their boats, tubs/showers, lawn urniture, swimmingpools, spas or saunas, arm implements or equipment, au-tomobiles, etc. There are plastic supply rms and automo-tive retail outlets that have products available or berglassrepair.

Inormation concerning health and saety regulations can beobtained rom OSHA, EPA, State and Local governing ocesor their websites. At the end o this chapter is a list o reer-ences including websites where more detailed inormationcan be obtained.

2. REGULATIONS

A. Federal RegulationsThe OSHA Hazard Commu-nication Standard, 29 CFR 1910.1200, requires employersto evaluate chemicals used in their workplaces to deter-mine i they are hazardous and to transmit inormationon hazardous chemicals to employees by means o a

comprehensive training and in-plant hazard communi-cation program.

OSHA establishes permissible exposure limits (PELs) orcertain chemicals, such as styrene, which has an indus-try voluntary standard or permissible exposure o 50ppm, and an OSHA PEL o 100 ppm.

SARA TITLE III (EPA, 40 CFR 355) requires emergency plan-ning, chemicals inventory reporting and toxic chemical

release reporting.The Resource Conservation Recovery Act (RCRA) in-cludes cradle to the grave regulations, governing thegeneration o storage, treatment, and disposal o haz-ardous waste.

The Clean Air Act Amendments o 1990 (CAAA) regulateemissions o hazardous air pollutants (HAP) and volatileorganic compounds (VOCs).

The Department o Transportation regulates shipment ohazardous materials and wastes.

B. State RegulationsState and/or Local regulations

must be at least as stringent as the Federal require-ments.

Caliornia regulations place limits on VOC emissions oresins and gel coats by limiting monomer content andrequiring specic application methods.

Caliornia also requires the label or data sheet to statethe amount o any VOCs in that product.

Caliornia Proposition #65 prohibits releases o certainchemicals into drinking water and requires clear andreasonable warning to persons potentially exposed tocarcinogens and reproductive toxins.

Other states, such as New Jersey and Pennsylvania,have regulations concerning hazardous materials.

Federal, State and Local regulations are constantly chang-ing. Publications and trade organizations, such as theACMA or NMMA, are good sources or tracking regulatoryinormation.

3. SAFETYCCP encourages its customers to develop aSaety Management System. Saety is the responsibility oevery employee. Fire losses and worker illnesses and in-juries have occurred where good work practices were notestablished or enorced.

The Saety Management System should designate theperson(s) responsible or the written saety programs (Haz-ard Communication, Personal Protective Equipment, Lock-out/Tagout, Conned Space Entry, Exposure Control, DisasterControl, etc.) and employee training. Supervisors and em-ployees should be aware o hazards (see MSDS), necessaryprecautions, and incident reporting responsibilities.

Periodic saety inspections are recommended. Material Sae-ty Data Sheets (MSDS) and other saety data or all hazard-ous materials ound in the work place must be kept on-site.All employees, supervisors and workers, should be aware o

proper handling and cleanup directions when handling anyhazardous material.

Part Two

In This Section1. Introduction2. Regulations3. Saety

4. Fire Hazards5. General Hazards o Materials Used6. Health Hazards

7. Electrical Hazards8. Equipment Hazards9. HSE Inormation


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HEALTH, SAFETY, and the ENVIRONMENTCCP strongly recommends that its customers establish anEmergency Action Plan or Emergency Response Plan oreach acility.

4. FIRE HAZARDSA re is dangerous, destructive andcostly. It can start rom a simple cause or a complicated one.Knowing how res start is the oundation to knowing how to

prevent one.

To sustain a re, there must be:

Fuel Oxygen Heat or an ignition source.

I you remove any one o these actors, a re cannot occur.

A. FuelQuantities o a uel source are required or are. Resins or gel coats, in the liquid state, are famma-ble uel sources. Resins or gel coats can also be com-bustible uel sources when cured, or as a dust. Most

cleanup solvents, catalysts, and waxes are uel sourc-es. Composites plants have the usual uel sources opaper, rags, wood, cardboard boxes, trash, etc. All uelsources must be careully controlled and minimized.

Resins and gel coats are ound in our states in a plant:

Liquid Vapor Solid Dust.

Vapors and dust are typically the most dangerous. Ex-cess vapors and dusts must be avoided. Keep contain-

ers closed or covered when not in use. Controlled dustshould be reduced and not allowed to accumulate.

Vapors are created rom spraying, heating rom curingparts, evaporation, etc. Vapors rom resin and gel coatare heavier than air (sink to the foor) and may collect inlow spots. Vapors and dust can normally be removedrom a plant by eective mechanical ventilation.

NOTE: Check or Federal, State, and Local codes on ex-hausting and/or discharging any materials directly intooutside air. These regulations must be ollowed.

Flammable liquid resin and gel coat are also danger-ous. It is essential to keep uncatalyzed resin and gelcoat in closed containers when not in use, and stored ina separate area away rom the work area until needed.Do not store in direct sunlight or where excess heat ispresent. Wipe up or remove all spills or over spray assoon as possible.

Liquid catalysts (peroxides) must be handled accordingto the manuacturers recommendations. Organic per-oxides can be explosive and are the most dangerousuel in a plant, because they provide oxygen and uelto a re. They should be kept in their original contain-

ers, out o direct sunlight, not exposed to heat, ree romcontamination, and closed when not in use.

Catalysts are oxidizing materials which will react (attimes explosively) with reducing agents, such as cobaltaccelerators, metals, and strong acid. A catalyst shouldnever be diluted with acetone. I a diluted catalyst is nec-essary, use catalysts obtained rom a catalyst manuac-turer or those diluents recommended by the catalysts

manuacturer.Catalyst must always be kept or used in containerswhich will not react with the catalyst. See the catalystmanuacturers MSDS or specic recommendations.Over-spray and catalyst mist must be minimized. Over-spray must be wiped up and removed immediately ac-cording to the manuacturers recommendations.

Special care must be taken with catalyzed resin or gelcoat (e.g., over sprays and gun fushings, as these mix-tures have the individual hazards o all the combinedmaterials o resins or gel coats, catalyst, solvent, etc.).In addition, the chemical reaction between the resin or

gel coat and catalyst produces heat which can possiblycause ignition o solvents, unmixed or high concentra-tions o catalyst, and other fammable materials. Theamount o heat generated will depend on the amounto catalyst, the degree o mixing, the temperature, themass, and the reactivity.

Catalyzed resin or gel coat must not be allowed to ac-cumulate. Gelled masses and sanding dust should beremoved at once or temporarily immersed in water untilthey can be removed.

Plant solid waste must be handled careully. Trimmings,

over-spray and trash have thin ragged sections whichcan be ignited. Trash should not be allowed to accumu-late. The cured parts are harder to ignite, but will burn.

Likewise, any nely divided solid material may presenta re or explosion hazard when dispersed and ignitedin air i the ollowing conditions are met:

The dust is combustible. A cloud is ormed exceeding the minimum

explosive concentration. A source o ignition is present. Dusts should

be minimized and not allowed to accumu-

late.Wax mold release agents are also uel sources. Careand caution must be used with these materials and thematerials used in their application and removal. See themanuacturers MSDS or instructions or handling, useand storage.

B. OxygenOxygen is necessary or any re. Thereare two main sources o oxygen: air and chemicallycombined oxygen in the material itsel. All volatile ma-terials must be within certain ratios with air or oxygento burn or explode. With polyesters (resins or gel coats),

good mechanical ventilation can dilute the uel below itsexplosive limit.



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HEALTH, SAFETY, and the ENVIRONMENTPeroxides are a special case. Peroxides contain chemi-cally combined oxygen which can be easily liberated orcombustion by heat, chemical reaction, decomposition,contamination, etc. Since peroxides are also uels, allthat remains or a re is heat or a source o ignition.

Because o this, peroxides require additional care to

be used saely. Storage should be separate rom otherfammable or combustible materials. Close containerswhen not in use. Spills, gun fushings, and over-spraysshould be removed immediately. See the manuactur-ers MSDS or recommendations.

C. HeatHeat or a source o ignition is necessary ora re. This can be a match, cigarette, fame, hot la-ment, exotherming resin or gel coat, heater, pilot light,spark (metal or hard surace or static), arcing o an elec-tric motor or wires, etc.

Dusts and vapors require a smaller ignition source than

liquids or cured parts to start a re.

To avoid these hazards, ignition sources must be re-moved rom spray areas, working and storage areas.

One source o heat that must not be overlooked is romthe chemical reaction o resin or gel coat and/or perox-ides. Polyesters produce heat when they gel and cure.The amount o heat produced depends on the amounto catalyst and its degree o mixing, the temperature,the mass, the resin to ller ratio, and the reactivity.

Trimmings, over-spray, fushed material rom sprayguns, and dust rom sanding and grinding should beremoved at once or temporarily dispersed in water untilthey can be removed.

A good saety program works to remove, control orminimize all three elements.

The ollowing results indicate that closed cup fashpoints are lower than open cup fash points. This dataalso shows that the addition o acetone to a gel coatsignicantly lowers the fash point.

FLASH POINT DATA

Material Closed Cup & FlashPoint (Approx.)

Acetone ................................ 0F

Methyl Ethyl Ketone ............. 20F

Ethyl Acetate ......................... 24F

Styrene .................................. 88F

Polyester Gel Coats ............ 79 to 88F

Methyl Methacrylate ............ 51F

CCP does not recommend the addition o acetone orany other solvent to resins or gel coats.

The ollowing extinguishing agents may be used onresin or gel coat res:

Foam Dry chemical Water og Carbon dioxide.

I electrical equipment is involved, the use o oam orwater should be avoided.

NOTE: Direct streams o water may spread a re involv-ing solvents or monomers due to incompatibilities anddensity dierences. The burning material oten foats onwater.

By properly handling catalysts and accelerators, control-ling vapors, and keeping the shop saely clean, muchcan be done to reduce the risk o re. With these actorscontrolled, a composites operation is relatively sae.

5. GENERAL HAZARDS OF MATERIALS USEDA. Catalysts (Initiators)Read the MSDS or all cata-lyst products. The catalysts required or curing resinsand gel coats are usually organic peroxides, such asmethyl ethyl ketone peroxide (MEKP) and benzoyl per-oxide. By their nature, organic peroxides are usuallyhighly fammable and may decompose explosively.

Initiators are tested or heat sensitivity, shock sensitivity,burning rate, fash point, storage stability, and reactionto blasting caps to determine their relative hazards.

Obtain the manuacturers MSDS and product inorma-

tion to learn more about how to saely dispose o un-wanted or old initiators.

According to NFPA 43B, incompatible materials (suchas accelerators) and fammable liquids should not bestored within 25 eet o organic peroxides. The eec-tive separation distance should be maintained by foorslope, drains, dikes, two-hour re wall, or detachedstorage building to prevent fammable liquid leaks romentering the organic peroxide storage area.

Only closed containers should be permitted in the stor-age areas. No more than a one day inventory quantity

o initiator should be brought rom storage into the workarea.

Initiators should never be added or allowed to contactaccelerator which has not been added and well mixedwith large, diluting quantities o resin or gel coat. Thebest procedure is to rst mix accelerator in the resin untila homogenous mix is obtained, then add the initiator.See manuacturers handling precautions.

A very small amount o peroxide initiator can make dras-tic changes in the physical properties o a resin or gelcoat. CCP emphasizes the importance o ollowing the

proper procedures in handling the commercial ormso these products. Failure to do so can lead not only to



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11) Do not let organic peroxides come in contactwith easily oxidized metals such as copper,brass, and mild or galvanized steel.

12) Most organic peroxide suppliers have saetyprograms available (including videos or CDs).Contact the supplier to request a Product Stew-

ardship visit.13) Always store organic peroxides at or below the

recommended temperature as specied by themanuacturer.

14) Red organic peroxides are believed by someto be less stable than clear. Rotate inventory ored organic peroxides requently.

15) These saety considerations are not all inclu-sive. The organic peroxides supplier shouldbe contacted or specic saety recommenda-tions.

B. AcceleratorsRead the MSDS. Some o the acceler-ators commonly used are extremely hazardous. Diethyl-analine (DEA) and dimethylanaline (DMA) are particularlyhazardous since even small splashes may be absorbedthrough the skin, resulting in contact dermatitis. Head-ache, nausea, breathing irregularities, or ainting mayoccur soon ater breathing vapors o these materials. Iexcessive quantities are inhaled, even more severe reac-tions, including poisoning or death, may occur.

C. Styrene and SolventsRead the MSDS. Somemonomers and cleanup solvents used may have healtheects. Physiological health problems may occur romoverexposure. For specic inormation regarding thehealth hazards o specic products, consult the manu-acturers Material Saety Data Sheet.

The accumulation o styrene and solvent vapors pro-vides one o the conditions or an explosion or fash re.A static charge or simple spark ignition source is all thatis needed. Vapors should be immediately removed bya good ventilation system.

Caliornia Air Quality Management District rules requirethat the maximum loss o volatile organic compounds(VOCs) o all VOC-containing products packaged in

quarts or larger be reported. This includes CCPs gelcoat and resin product lines.

As a result, a series o tests were perormed accordingto the Standard Method or Static Volatile Emissions oncatalyzed polyester resins and gel coats. The maximumquantity o VOCs not consumed during polymerizationwas ound to be 40 grams per liter (or 230 grams permeter considering surace area exposed to air) or allcatalyzed CCP resins and gel coats measured in a gal-lon can lid. For all uncatalyzed CCP resins and gel coats,the maximum VOC content is 600 grams/liter.

Copies o this VOC content inormation should be re-tained and available or compliance inspections.

Depending on the application equipment, the temper-ature, and gel time, gel coats may lose 20 to 25 per-cent o the pounds sprayed, or up to 65 percent o themonomer(s) present.

Styrene, a typical monomer, can be lost rom gel coatsin two ways. When gel coat is atomized, styrene evapo-

rates as the gel coat travels rom the end o the gun tothe mold. The loss o styrene at this point is controlledby temperature, method o atomization, spray distance,and the degree o breakup (atomization).

The second loss occurs as the gel coat cures on themold. During this time period, the loss is governed bythe evaporation rate o styrene. Once the surace lm isgelled, the evaporation rate drops o dramatically. Thisloss o styrene is infuenced by the gel time, tempera-ture, lm thickness, surace area, mold conguration,and air movement.

Styrene monomer is fammable and orms explosivemixtures with air:

The lower explosive limit is: 1.1 percent. The upper limit is: 6.1 percent (percent by

volume).When styrene vapor is present in concentrations be-tween these limits, any source o ignition can cause anexplosion.

Styrene Ignition Temperatures

Flash point is the lowest temp-

erature at which a substancegives o enough vapors toorm a fammable or ignitablemixture with air near the suraceo the substance being tested.

Flash point o

styrene is 31C(87.8F)

Fire point is the lowest temp-erature at which a liquid in anopen container will give oenough vapors to continue toburn when ignited. Fire pointsare generally slightly abovefash points.

Fire point o styreneis 34C (93.2F).

Auto-ignition temperature is thelowest temperature required toinitiate or cause sel-sustainedcombustion in the absence o aspark or a fame.

Auto-ignition temp-erature o styrene is490C (914F).

Adequate ventilation (especially the use o ume hoods)is recommended. Open fames, local hot spots, riction,and static electricity must be avoided.

D. Disposal o Cured Unsaturated PolyesterDis-carded solid plastic materials rom a manuacturingprocess utilizing unsaturated resins or gel coats cured

with organic peroxides, like methyl ethyl ketone per-oxide, constitute an industrial solid waste. As required




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by 40 CFR 262.11 (and corresponding applicable stateregulations), the generator o this waste is required todetermine i it is a hazardous waste.

This process would involve the determination i the solidwaste is classied as a listed hazardous waste, eitheras a discarded commercial product (40 CFR 261.33), as

a specic source waste (40 CFR 261.32), or as a nonspe-cic source waste (40 CFR 261.31). The generator mustthen determine whether the waste meets the charac-teristics o hazardous waste dened in 40 CFR 261, Sub-part C. These dened characteristics are:

Since the waste is not a liquid with a fash point o lessthan 140F, a non-liquid which may ignite spontane-

ously or by riction, an ignitable compressed gas, or anoxidizer, it does not exhibit the characteristics o Ignit-ability. Likewise, the waste does not exhibit the char-acteristics o Corrosivity (aqueous pH less than two orgreater than 12.5 or corrodes steel) or o Reactivity (i.e.,normally unstable, violently water reactive, or capableo generating toxic gases, vapors or umes in contactwith water). Depending on the level o methyl ethyl ke-tone peroxide used, the solid waste may be classiedas hazardous because o toxicity. Methyl ethyl ketone islisted in Table 1 o 20 CFR 261.24.

All generators o solid wastes o this nature should re-

tain a written determination in their records with docu-mented data or generator knowledge on waste prolesor all wastes which they generate. This is required byFederal and State regulations.

6. HEALTH HAZARDSRead the MSDS or health hazardwarning inormation or all materials used in the workplace.Most materials used in a manuacturing acility may be haz-ardous i not properly or careully handled. Each chemicalshould be considered separately, and looked at in reerenceto other chemicals with which it can come in contact or reactwith to produce new chemicals. Chemicals may enter the

body through several routes o entry including inhalation, in-gestion, absorption, or injection. Consult the MSDS (MaterialSaety Data Sheet) to determine acceptable exposure levelsand emergency response procedures.

Both the OSHA Hazard Communication Standard and cer-tain state regulations require that manuacturers place pre-caution labels on containers o manuactured products, andprovide to each customer Material Saety Data Sheets thatlist the acute (immediate) and chronic (delayed) hazards otheir products.

Contact with hazardous materials must be minimized. Res-

ins, gel coats, solvents, initiators, etc., should not come incontact with the body. Where contact is unavoidable, protec-

tive equipment (clothing, gloves, etc.) should be used and allspills cleaned up at once.

Saety glasses or goggles must be worn at all times in allworking areas.

I the possibility o vapor or dust is present, adequate ven-tilation is necessary. NIOSH-approved hood type supplied

air respirators are recommended or applications with highvapor or dust levels. NOTE: Air supplied to the hood mustbe absolutely clean and separateno exhaust vapors orcompressor oil. All dusts should be removed by adequateventilation and with an adequate ace mask being worn. Donot use air to blow dust o a person. Remove by washingwith cool water.

Pigments used by some gel coat suppliers may contain leadand hexavalent chromium compounds. OSHA regulationsrequire workplaces with lead containing materials to moni-tor worker exposure. Because o the number o recognizedhealth hazards associated with the use o lead and heavymetal pigments, CCP does not use lead or heavy metal pig-ments in its resin or gel coat products.

Two types o lead/chromium pigments used by some gelcoat suppliers are described as:

CHROME YELLOW

Classied as Light and Primrose Contains Lead Chromate Lead is a reproductive toxin and aects various

body systems and organs adversely. Hexavalent Chromate is considered a respira-

tory carcinogen.

MOLY ORANGE

Bright Orange and Scarlet shades Is a compound o Lead Chromate, Lead Molyb-

date and Lead Sulate Has the same lead and chromate hazards as

Chrome Yellow.

Many states have regulations to control the use and wastedisposal o mixtures containing lead and hexavalent chro-mate. The OSHA Occupational Exposure to Lead Standard,29 CFR 1910.1025, denes requirements o workplaces with

employees who may be exposed to lead. Compliance pro-cedures required by this standard include:

A. Make an initial determination o employee expo-sure by monitoring the work space in which lead maybe present.

B. Employee exposure is that exposure which wouldoccur i the employee were not using a respirator.

C. Notiy employees within ve days o the receipt omonitoring results that represent that employees expo-sure.

D. I monitoring results showemployee exposure to

be at or above the action level o 30 micrograms o leadper cubic meter, additional monitoring is required.



Dened Characteristics o Hazardous Waste

Ignitability Corrosivity Reactivity Toxicity


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E. I monitoring results showemployees are exposedto lead above the permissible exposure level o 50 mi-crograms per cubic meter, periodic monitoring, medicalsurveillance, engineering controls, employee notica-tion and respirators may be required.

I the decision is made to monitor or lead or chromium,

qualied industrial hygiene consultants or monitoringand testing services may be obtained by contacting:

American Industrial Hygiene Association2700 Prosperity Ave., Suite #250Fairax, VA 22031Ph: 703-849-8888Fax: 703-207-3561www.aiha.org

7. ELECTRICAL HAZARDSThe two main hazards romelectrical equipment are sparks and shock. All equipment,power lines, lights and connectors should be explosion-

proo and eectively grounded.All possible sources o static discharge should be eliminatedthrough adequate grounding or other measures. This in-cludes spray guns, holding tanks, transer lines, etc.

8. EQUIPMENT HAZARDSA composites operation mayuse many power tools. All tools which have exposed turn-ing parts should have guards to prevent hands and clothingrom being caught in them. All persons should be properlytrained in the use o power tools. Spray guns should begrounded, worn ttings and hoses replaced.

NOTE: Airless spray equipment develops enough pressureto orce material through the skin. Saeguards must be takento prevent this. Any person who sprays, regardless o equip-ment type, must be adequately trained and be made awareo how to protect himsel and others rom these hazards.

Beore starting repairs on spray equipment or any equip-ment with moving parts or internal pressure, turn o anddisconnect all power sources and bleed o ALL internalpressures. Care must be taken with chopper guns becausecutting blades and glass roving cut anything with which theycome in contact.

Well-run housekeeping and order programs that includetrash removal, spill cleanup, and regular equipment andbuilding maintenance, will reduce re and health hazardsin the workplace. Such programs save money, promote e-ciency, and increase job satisaction.

9. HEALTH, SAFETY, AND ENVIRONMENTAL INFORMA-TIONThe reerences listed below are given as a guideonly. This is not meant as a recommendation or endorse-ment o any o these reerences or services. They are listedas a sample o the type o inormation that is available.

There are many sources o inormation and guidance on

health, saety and environmental matters, or example:

Company insurance carrier Local Fire Marshall Suppliers (product stewardship)

Other sources o inormation are:

REGULATIONS/COMPLIANCE

United States Environmental Protection Agency (EPA)

www.epa.gov

United States Department o Transportation (DOT)www.dot.gov

Occupational Saety and Health Administration (OSHA)www.osha.gov

American Composites Manuacturing Association1010 Glebe Rd., Ste 450Arlington, VA 22201Ph: 703-525-0511Fax: 703-525-0743www.acma.org

National Marine Manuacturers Association (NMMA)

200 E. Randolph Drive, Ste 5100Chicago, IL 60601Ph: 312-946-6200www.nmma.org

FIRE SAFETY

National Fire Protection Association (NFPA)www.npa.org

No. 13 Sprinkler SystemsNo. 30 Flammable and Combustible

Liquids CodeNo. 68 Explosion Venting GuideNo. 69 Explosion Prevention SystemNo. 70 Electric Code

No. 77 Static ElectricityNo. 91 Blower and Exhaust SystemNo. 654 Prevention o Dust Explosions

in the Plastics Industry

CHEMICAL HEALTH HAZARDS

National Toxicology Program (NTP)National Institutes o Healthwww.nih.gov

Styrene Inormation Research Center (SIRC)www.styrene.org

International Agency or Cancer Research (IARC)World Health Organization

www.iarc.rCOMPLIANCE GUIDES

J. J. Keller and Associates, Inc.Ph: 800-327-6868

LabelmasterPh: 800-621-5808

Thompson Publishing Co.Ph: 800-677-3789

Business & Legal Reports, Inc.Ph: 800-727-5257www.blr.com

Summit Training Source, Inc.

Ph: 800-842-0466




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FRP COMPOSITES: IntroductionPart Three, Chapter I

In Part Three:Chapter I: IntroductionChapter II: General Chemistry o FRP Com-

posites ResinsChapter III: General Properties o FRP Com-

posites ResinsChapter IV: Fabrication o FRP Composites

A composite material is an engineered product made bycombining dissimilar materials that remain separate anddistinct rom each other on a macroscopic level. The result-ing material has a unique set o characteristics and quali-ties that is more useul than any o its individual constituentmaterials.

Any composite consists o a matrix material and a reinorc-ing material. The matrix surrounds the reinorcement, main-taining the relative positions o the reinorcements. The ma-trix serves to transer loads rom the surace o the part intothe reinorcement material and between reinorcements. Al-most any material can ulll the matrix role. A ew exampleso broad categories o matrix are:

Mud Cement Pitch Rubber Plastic Ceramic Carbon Metal. Glass

The reinorcement can take numerous orms such as:

Powdered or aggregate minerals Whiskers (very short bers) Chopped bers Continuous bers.

Fibers can be ashioned into textile products such as eltsor cloths, or abrics o various constructions. Fiber materi-als can be composed o a wide variety o materials such asglass, carbon, silicone carbide, boron, mixed ceramics, anumber o dierent polymers, and naturally occurring mate-rials such as hemp.

Composite materials are dierent rom conventional ma-terials in many ways. Most signicantly, they achieve theirproperties and characteristics only ater being successullyprocessed in the manuacturing acility. They are composedo truly raw materials. Age o materials, their storage, andprocessing temperatures are only three o the variables thatmust be managed and controlled.

In contrast, a so-called raw material such as aluminumsheet arrives on a skid with all o its properties and charac-teristics intact, and it keeps them indenitely, barring somevery extreme exposure conditions. The handling and usage

o composite materials is not unlike the handling and usageo ood items. Quality requires reshness, while consistencyrequires adherence to the recipes and attention to processdetails. It is no surprise that this application guide has be-come known throughout the world as the Cook Book.

Composite materials consisting o Glass Fiber ReinorcedPolyester (GFRP) resin are in widespread use throughoutthe world. These are generally considered commodity typecomposite materials. Applications range rom berglass

bathware to solid-surace counter tops to decorative statuesto vehicular body parts to windmill blades and more. Almostanything can be molded using GFRP.

Glass bers are composed o a mixture o inorganic met-al oxides. The principle constituent is silicone dioxide withsmaller amounts o aluminum oxide, calcium oxide, mag-nesium oxide, boron oxide, and zirconium oxide. Exactcomposition determines the end-use perormance. Thereare at least seven commercially available glass types withthe most common being E glass, ollowed by A glass andthen C and S glass. Quartz ber is essentially pure silicone

dioxide and eatures one o the lowest dielectric constants ocommercial materials.

The class o resin chemistry determines the end-use suit-ability or any application. Unsaturated polyester resins pro-vide a good balance o properties or a modest cost. Vinylester resins oer improvements in certain properties such asstrength and heat resistance, but at a cost premium.

Fiber Reinorced Plastic (FRP) parts are molded to the designshape by using a cure tool and a molding protocol. Mostcure tools are called molds, although not all molds are cur-ing tools. The most common exception is a ber pre-ormingmold. A cure tool can consist o several elements. At its veryminimum, a cure tool consists o a mold skin which mirrorsthe cured part about its external surace. Larger molds in-corporate bracing to reinorce local areas and raming todistribute the mold weight onto concentrated load pointssuch as casters, which also provide or mobility.

This guide pertains to one specic type o composite knownas Fiber Reinorced Plastic (FRP). The major subcategory oFRP is Glass Fiber Reinorced Plastic (GFRP or GRP). All threeterms are sometimes used interchangeably.



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FRP COMPOSITES: General Chemistry oFRP Composites ResinsPart Three, Chapter II

1. INTRODUCTIONThermoset polyester and vinyl esterpolymers are the starting point or most CCP resins and gelcoats. They are the basis or RTM, marble, casting, laminat-ing and molding resins.

These resins are very versatile and are used in a broadspectrum o applications, including:

Building and construction

Corrugated and fat paneling

As reinorcement or acrylic sheet

In shower stalls, tubs and marble vanities

In both interior and exterior auto body panels

In polymer concrete and mine bolts

In electrical components

In boat and other marine laminates

In corrosion-resistant tanks and components.

They are the major component in buttons, simulated wood

castings and bowling balls. They can be ormulated romrigid to fexible (or anywhere in between) and can be corro-sion and water resistant. They can be used unlled, lled, re-inorced, or pigmented. Fabricators can cure polyester resinsat temperatures that range rom ambient up to 400F.

When armed with a knowledge o how polyester and vinylester resins are made and how they cure, the abricator willmore readily understand some o the things that aect them.This will support good use techniques with ewer problems.Knowledge and experience together provide the oundationor ecient production methods and high quality parts.

This chapter o the Applications Guide oers a brie descrip-tion o the chemistry o thermoset polyester and vinyl esterresins. It is a guide to how they are made and how theycure. Further inormation is available in the reerences listedat the end o this chapter.

2. SYNTHESIS OF POLYESTER AND VINYL ESTER POLY-MERSThe building blocks or synthesis o polyester andvinyl ester polymers generally come rom the petrochemicalindustry. Their ultimate source is oil and/or natural gas. Theyare primarily composed o carbon, hydrogen and oxygen.For unsaturated polyesters, they all into three types o com-pounds: dibasic acids, glycols, and monomers/diluents. For

vinyl esters, the building blocks are diepoxides, monounc-tional acids, and monomers or diluents.

For polyester chemistry, the acids and glycols join togetherunder heat to orm a long chain called a polymer. Becausethe acids and glycols react together to orm an ester in whatis called an esterication reaction, the resulting polymer iscalled a polyester (literally many esters). Some o the diba-

sic acids are unsaturated and or this reason the polyesteris said to be an unsaturated polyester. To orm the polymer,the acids and glycols are cooked together in a kettle. Cook-ing time can vary rom 14 to 24 hours at temperatures up to430F. The progress o the cooking processor cookisollowed by measuring the reduction in acidity and the in-crease in viscosity. A by-product o the reaction is water thatboils out o the reaction kettle as it is ormed.

Vinyl esters also orm similar unsaturated esters via an ad-dition reaction between the epoxy unction and acids. Theunsaturated part typically comes rom the methacrylic acid

rather than maleic acid as is the case with unsaturated poly-esters. Processing conditions are typically eight to 14 hoursat temperatures up to about 246F. Processing parametersare very similar to unsaturated polyesters, however, no wa-ter is eliminated as this is an addition rather than condensa-tion reaction.

The polyester or vinyl ester polymer is generally a hard sol-id, similar to a chunk o glass. To make it readily usable bythe abricator, it is dissolved in a monomer, usually styrene,which also has an unsaturated portion. When the abrica-tor adds a peroxide catalyst, the unsaturated portion o themonomer reacts with the unsaturated portion o the poly-

mer. The resulting material is a hard solid that will not sotenor melt even when heated to very high temperatures. Forthis reason, the resin is said to be a thermoset resin.

3. TYPES OF POLYESTER AND VINYL ESTER RESINSThenal properties o the polyester resin depend on the acids,glycols, and amount o unsaturated acid used in making thepolyester polymer. The most common unsaturated acid ismaleic anhydride. Maleic anhydride converts to maleic acidand then nally to umaric acid during the cooking process.Saturated acids include phthalic anhydride, isophthalic acid,and adipic acid. Glycols include ethylene glycol, diethyleneglycol, propylene glycol, dipropylene glycol, and neopentylglycol.

Styrene monomer is nearly always used, but other mono-mers that can be used are vinyl toluene, alpha-methyl sty-rene, and methyl methacrylate. The structures o some othese components are shown on the ollowing page.

Each o these components contributes to the nal propertieso the resin. Isophthalic acid and neopentyl glycol increasemoisture, chemical and corrosion resistance. To improve re-sistance to weathering, neopentyl glycol, methyl methacry-late, and stabilizing additives that protect against ultravioletrays o the sun, are used. Addition o adipic acid plus re-

ducing the amount o unsaturated acid results in a soterresin with increased fexibility. In contrast, to increase rigidity,

In This Chapter1. Introduction2. Synthesis o Polyester and Vinyl Ester Poly-

mers3. Types o Polyester and Vinyl Ester Resins

4. Curing Mechanism5. Peroxide Catalysts6. Accelerators

7. Suggested Reerences



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higher amounts o unsaturated acid are used, sometimeswith higher-unctionality monomers such as divinylbenzene.These materials result in greater hardness and rigidity byincreasing the number o chemical bonds o the resin asit cures. To alter the fammability characteristics o a resin,acids such as chlorendic anhydride and tetrabromophthalic

anhydride are used.

Another building block, generally used in laminating resins,is dicyclopentadiene (DCPD). It replaces some o the glycoland contributes a aster tack ree time with lower apparentshrinkage and a smoother surace on cure. These resinsare primarily used in structural applications which requirean excellent cosmetic appearance and reduced ber print-through.

As with unsaturated polyester, the nal properties o vinylester resins are very dependent on the choice o polymerconstituents. The most common and basic vinyl ester resinsemploy the diglycidyl ether o bisphenol-A as the diepoxy,and methacrylic acid as the unsaturated mono-acid. Thestructures o these components are shown below:

Modications o this basic structure may include using a no-valac epoxy (a multi-unctional epoxy), maleic acid, bisphe-nol-A or other monounctional acids in addition to the basicingredients. The modications can impart either increasedstrength, increased fexibility, or modied cure behaviors de-pending on the choices made.

The choice o monomers or vinyl esters is very similar to thato unsaturated polyesters. Vinyl esters are selected or ap-plication where mechanical strength, and/or chemical or

water resistance demands are greater than can typically beobtained by conventional unsaturated polyester resins.

In addition to unsaturated polyester and vinyl ester resins,CCP markets resin systems that are a combination o bothpolyester and urethane; that is, the CCP XYCON hybrids.The properties o these hybrids refect these two chemistries.They have excellent toughness, adhesion, water resistance,and speed o cure. They are used as a barrier coat in marine

applications to reduce ber print-through and increase blis-ter resistance. In addition, they can be ormulated or use instructural applications.

4. CURING MECHANISMAs previously noted, ater thepolyester or vinyl ester polymer is cooked, it is dissolved inmonomer (usually styrene) so that it is a readily pourablefuid that can be easily used by the abricator. The ratio opolyester polymer to monomer ranges rom 75:25 to 50:50parts by weight. At this point, additives called inhibitors areadded to the solution to prevent the monomer and the un-saturated acid in the polymer rom reacting together untilthe abricator adds a peroxide catalyst.

Gel and cure o a polyester or vinyl ester solution takes placeby a ree radical reaction. In this procedure, a peroxide cata-lyst is added to the polymer solution. The peroxide catalystsplits apart into highly energized ree radicals which attackthe unsaturated portions o the polymer and monomer. Thepresence o the ree radicals together with the unsaturatedunctionalities o the polymer and monomer permit the orma-tion o new chemical bonds to crosslink the resin system.

Once crosslinking starts, movement o the solution is highlyrestricted. Ater a small raction o the unsaturated groupshave linked together, the solution is gelled. Eventually the

polymer chains are crosslinked by the monomer into onesolid, inusible mass that will not soten or melt on exposureto heat. Typically in laminating and casting applications, 80to 90% o the unsaturated groups (which ultimately react)will have joined together by the time the part is demolded.The parts will reach 95 to 97 percent cure in two to ourmonths i kept above 70F. Curing is accompanied by thedevelopment o large amounts o heat, commonly reerredto as exotherm. This is the result o the new chemical bondsorming and makes the reaction proceed even aster.

Inhibitors are used to delay crosslinking until the appropriateperoxide catalyst is added. Free radicals can orm naturally

in the resin, and can orm aster i the polymer solution isexposed to heat and/or sunlight, or is contaminated withmetals or other materials. The inhibitors seek out the reeradicals and destroy them. For this reason it is important tostore polyester resins in a cool, dark place as recommendedon CCP data sheets.

Factors that aect the curing reaction are:

Temperature o the resinthe rate o gel andcure will double with each increase in tem-perature o 18F. Conversely, it will halve i thetemperature decreases by 18F. I the tempera-

ture is too low, the polyester may never cureproperly.


FRP COMPOSITES: General Chemistry o FRP Composites Resins


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Massthe amount (mass) o resin and itsshape will aect the rate o cure. A large, thickcasting will cure aster than a thin laminate be-cause the casting will hold the exothermic heatbetter than the laminate. Very thin laminatesmay require a source o external heat to cure

properly. Catalystthe type and amount o peroxide cat-

alyst are based on the resin and curing condi-tions. CCP data sheets speciy recommendedtypes and amounts. Peroxide catalysts are dis-cussed in the ollowing section.

Acceleratorsaddition o accelerators speedsup the curing mechanism greatly. CCP addsaccelerators (promoters) to its resins. Accel-erators are discussed in a ollowing section.

5. PEROXIDE CATALYSTSThe unction o the peroxide

catalyst is to crosslink the resin, at rst causing a gel andthen a complete cure. When a peroxide catalyst is addedto a resin, heat and/or the accelerators in the resin splitthe peroxide catalyst into ree radicals. The ree radicalsrst consume the inhibitor present in the resin and then at-tack the unsaturated portions o the polyester polymer andmonomer. These activated unsaturated groups become reeradicals themselves, and then add onto other unsaturatedgroups until long polymer chains are ormed. The wholeprocess stops when the ree radicals are no longer mobileenough to contact other unsaturated groups. This happenswhen the viscosity o the curing system becomes very high.

The remaining groups slowly crosslink as the part ages orwhen it is heated in a postcure step by the abricator.

The catalysts used with polyesters and vinyl ester resins arecalled peroxides. Some are very unstable at room tempera-ture and must be stored under rerigeration. Because per-oxides and accelerators react explosively, they should neverbe mixed together directly. For this reason, resins or use atroom temperature generally come pre-accelerated (or pre-promoted). I additional accelerator or promoter is needed, itshould be mixed thoroughly into the resin beore the perox-ide catalyst is added. The precautions listed in the MaterialSaety Data Sheet or the peroxide catalyst should be strictlyobserved.

Curing o polyester and vinyl ester resins can be divided intotwo groups: room temperature (65 to 95F) and elevatedtemperatures. Curing at elevated temperatures gener-ally takes place in heated tools or molds at temperatureso 180F to 320F. Peroxides chosen or use at these tem-peratures include t-butyl perbenzoate, t-butyl peroctoate,benzoyl peroxide, peroxyketals, and other specialty perox-ides designed by catalyst manuacturers. Accelerators arenot generally needed to activate these peroxides. Heat isenough to break them down into ree radicals. These per-

oxides are generally liquids or are dissolved in diluents tomake them easy to use.

Room temperature is generally used in casting and lami-nating applications. Methyl ethyl ketone peroxide (MEKP);cumene hydroperoxides (CHP); 2,4-pentanedione perox-ide (2,4-P); or combinations o these peroxides are gener-ally used. To make them usable, they are diluted with vari-ous plasticizers to an active oxygen content o our to nine

percent. Accelerators in the resins split these catalysts intothe ree radicals necessary or the gel and cure process.

MEKP is made rom methyl ethyl ketone and hydrogenperoxide. These materials can combine to orm dierentperoxides called isomers. The MEKP supplied by mostmanuacturers is a mixture o these isomers and dependson the manuacturing process. Thus MEKPs rom dierentmanuacturers react dierently and should be checked be-ore switching rom one to another. There are also smallamounts o water and hydrogen peroxide in MEKP. Thesecan also change the reactivity o the MEKP.

Some o the actors governing peroxide catalyst usageare:

AmountAn adequate amount o peroxidemust be used to start the process and bringit to nal cure. Resins and peroxide catalystsare ormulated so that rom 0.75 to three per-cent catalyst solution is enough to generatethe ree radicals needed. I too much catalystis used, too many polymer chains will startgrowing. In addition, they will all be shortchains and the cured resin will be weak and

have poor physical properties. I too little per-oxide catalyst is used, the gel time will be verylong and the growing polymer chains may dieout beore all the unsaturated groups are re-acted. The resin may never cure properly eveni post cured. It will tend to be physically weakand possibly rubbery.

HeatEnough heat must be supplied to prop-erly cure the resin. It can come rom an ex-ternal source such as an oven, heat lampsor a heated mold. The heat can also comerom the exotherm o the resin itsel. Exothermis the heat given o as the resin cures. I theexotherm is more concentrated, such as in athick casting, the part will get hotter and cureaster. I the part is a thin laminate the exother-mic heat will be dissipated through the largesurace area o the laminate and cure will beslower.

Shop conditions are very important. I temperatures arebelow 60F, cure will be greatly extended. However, i thetemperature is in the 90s, gel and cure will be aster. Cut-ting back on the peroxide catalyst may result in enough

working time, but there may not be enough ree radicals toproperly cure the resin.




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6. ACCELERATORSResins ormulated or cure at roomtemperature contain accelerators (also called promoters).They increase the breakdown rate o the peroxide catalystinto ree radicals. The amount o both accelerators and per-oxide catalyst must be such that the abricator has enoughworking time to orm the part, and, at the same time, enough

speed o cure to make the process economically practical.CCP adds accelerators to its gel coats and resins (i.e., pre-promotes them). Gel coat and resin data sheets containinormation on the type and amount o peroxide catalyst touse. CCPs resins are tailored to meet abricators needs; i.e.,ast gel and cure, ast gel with slower cure or longer trimtime, longer gel with ast cure, etc.

Accelerators used in CCP products are generally metal salts(sometimes called metal soaps) and amines. They includecobalt, calcium, copper and potassium salts and aminessuch as dimethyl aniline and diethyl aniline.

Some o these accelerators are described as ollows: CobaltSolutions o cobalt contain rom six to

percent metal. They impart a pink to red color

to the resin depending on the amount used.Cobalt acts on most peroxide catalysts to ormree radicals. Cobalt also aects perbenzoateand peroctoate catalysts that are used at inter-mediate temperatures (140F to 180F). Cobaltdoes not act as an accelerator or benzoyl per-

oxide. AminesAmines generally color polyester res-

ins yellow to brown depending on the amountpresent. They also can cause accelerated yel-lowing o cured parts. Dimethyl aniline (DMA)and diethyl aniline (DEA) do not act directly onMEKP or on 2,4-P. They increase the ability ocobalt to split these peroxides into ree radicals.They are very eective in shortening the curetime and hardness development o MEKP-cata-lyzed resins.

DMA and DEA act directly with benzoyl peroxide so that this

catalyst can be used at room temperature. Without an aminepresent, BPO is too slow in generating ree radicals at ambi-ent temperatures or use in polyester or vinyl ester resins.


BOOKSPlastics Engineering Handbook othe Society o the Plastics IndustrySociety o the Plastics Industry, Inc.(SPI)1667 K Street NW, Ste 1000

Washington, DC 20006Ph: 202-974-5200Fax: 202-296-7005www.socplas.org

Plastics HandbookMcGraw-Hill, Inc.2 Penn PlazaNew York, New York 10121-2298Ph: 877-833-5524www.books.mcgraw-hill.com

Reinorced Plastics HandbookElsevier Science Customer Service11830 Westline Industrial DriveSt. Louis, MO 63146 USAPh: 800-545-2522Fax: 800- 535-9935www.books.elsevier.com

PAPERS

Annual Conerence ProceedingsAmerican Composites Manuac-turing Association1010 North Glebe Road, Ste 450Arlington, VA 22201

Ph: 703-525-0511Fax: 703-525-0743www.acmanet.org

Annual ProceedingsComposites Institute ConerenceSociety o the Plastics Industry, Inc.(SPI)1667 K Street NW, Ste 1000Washington, DC 20006Ph: 202-974-5200Fax: 202-296-7005www.socplas.org

PERIODICALS

Composites Manuacturing1010 North Glebe Road, Ste 450Arlington, VA 22201Ph: 703-525-0511Fax: 703-525-0743

www.cmmagazine.org

Composites Technology4891 Independence Street, Ste 270Wheat Ridge, CO 80033Ph: 303-467-1776www.compositesworld.comModern PlasticsCanon Communications LLC11444 W. Olympic Blvd., Ste 900Los Angeles, CA 90064Ph: 310-445-4200www.modplas.com

Proessional BoatbuilderNaskeag RoadP.O. Box 78Brooklin, ME 04616Ph: 207-359-4651Fax: 207-359-8920www.proboat.com

7. SUGGESTED REFERENCES



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FRP COMPOSITES: General Properties oFRPComposites Resins

1. INTRODUCTIONFiber Reinorced Plastic (or Glass Re-inorced Plastic) is an adaptable material. The uses o FRPcover a broad range o applications. This chapter oers abrie outline o the properties that make FRP such a useulmaterial.

In the past, the comparison o physical properties o onemanuacturers laminating resin to another, based on sup-pliers data sheets, has been used to make many materialselections. This practice, though common, is fawed and canlead to poor material selection decisions.

In general, most manuacturers report the physical prop-erties o products as measured in both a casting and alaminate. ASTM methods are ollowed during the prepara-tion and testing o the sample at all resin manuacturers.However, within ASTM guidelines, variations are allowed in

the construction o the samples (e.g., catalyst type and level,post-cure cycle, and the use o glass panels versus Mylar).These variations can cause airly drastic dierences in theproperties reported on the data sheets.

In addition, other variances can occur while testing the ma-terials. I the test samples are not prepared in the same way,dierences can occur. CCP participated in a double blindround robin study where liquid samples o ve competitorswere provided to one another. Each company made cast-ings and laminates based on their own protocols or ollow-ing ASTM methods. Then, each company ran physical prop-erties and reported results. In general, relative perormance

dierences between the materials were discernible by alllaboratories involved. In addition, in comparison o resultsor any given material it was observed that some laborato-ries tend to report higher physical properties than others.

Thereore, comparing physical properties as listed on datasheets can lead to incorrect assumptions that one material isbetter than another. To avoid such inaccurate comparisons,it is advisable to prepare and run side-by-side samples onthe same piece o equipment in the same laboratory. Thiswill narrow the number o variances and yield numbers thatcan be compared.

In general, data sheets should only be used as generalguidelines or suitability o a material or a given applica-

tion, and to compare materials manuactured by a single

supplier.

2. MECHANICAL PROPERTIESThe tensile, compressiveand fexural properties depend on the reinorcement ma-terial (cloth, roving, woven roving, mat, etc.), the reinorce-ment to resin ratio, and how the reinorcement is orientedto the direction o the stress. The reinorcement bers canbe arranged, during abrication, in the direction o knownstresses so that the strength o the reinorcement is usedmore economically and better perormance is achieved.

For instance, reinorcement roving can be used in areas

where direct tension occurs, and reinorcement mat whereisotropic (random) compression stresses occur. A rod madeo parallel glass roving strands can have a tensile strength o150,000 psi whereas a sprayup laminate (made o choppedglass bers) may have a tensile strength o 15,000 psi. Acombination mat and woven laminate will have tensile andfexural strengths rom 30,000 to 50,000 psi.

Impact strength o FRP is high because it has no yield point(as contrasted with metal). This property eliminates denting,gives the structure dimensional integrity and makes it easy torepair (since it does not lose shape, even when ruptured).

3. PHYSICAL PROPERTIESThe specic gravity o FRP is lowin relation to other structural materials (about 1.7 dependingon glass-to-resin ratio). An extremely high strength-to-weightratio is available (important to the aircrat industry).

The thermal conductivity is very low or a solid material(2BTU/(hr/t2)F/t) which is not only important to insulatedstructures, but makes the surace pleasing to the touch inhot or cold ambient conditions.

A Barcol 934-1 Impressor is used in measuring hardnesso an FRP laminate. A Barcol 934 Impressor should show areading o 35 to 45 when the laminate has cured. More rigidresins will give a higher Barcol reading while resilient andfexible resins, o course, will give a lower reading.

Because o thin and inconsistent gel coat lms, the use o theBarcol Impressor is not recommended.

The heat distortion point o the laminate depends on the typeo resin and reinorcement used. General purpose polyestersrun about 200F where a high heat distortion polyester runsup to 275F. Continuous operating temperatures should notexceed 160F or general purpose room-temperature-curedpolyester resins.

The thermal coecient o expansion is slightly higher thansteel and about the same as aluminum: 13 x 10-6in./in/F.

In This Chapter 1. Introduction

2. Mechanical Properties3. Physical Properties

4. Chemical Properties

5. Electrical Properties 6. Fire Resistance 7. Optical Properties 8. Weathering Properties 9. Polyester Shrinkage

Part Three, Chapter III



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4. CHEMICAL PROPERTIESAlthough some chemicalscan attack FRP rather rapidly, FRP has excellent resistance toaqueous solutions (salts, acids, etc.). General purpose poly-esters have poor resistance to strong alkalies and do notstand up to certain strong acids (such as nitric) or high tem-perature solutions (over 140F). Special polyesters are used

in these applications.This generally high degree o chemical resistance o FRPmakes it particularly useul or tanks, hoods, covers, pipes,ducts and other structures in paper, textile, ertilizer, sewagedisposal and petroleum chemical plants.

Certain solvents such as ketones (acetone) and those hav-ing chlorine (carbon tetrachloride and chloroorm) solvate allpolyester resins rapidly.

5. ELECTRICAL PROPERTIESA unique property o FRP isthat it is electrically transparent. This is particularly useul inthe manuacture o radomes, Doppler systems, etc. Polyes-

ter resins generally have a low dielectric constant makingthem good potting materials or capacitors and other electri-cal equipment. FRP is an exceptionally good insulator, hav-ing a dielectric strength o 300 to 500 volts/mil. Polyesterscan be made (i desired) to be electrically conductive.

6. FIRE RESISTANCEAll resins, being organic, will burn.However, most re codes call or a certain maximum burn-

ing rate or certain characteristics which are available in spe-cial halogenated polyester resins or through the addition oalumina trihydrate.

7. OPTICAL PROPERTIESMost general purpose polyesterberglass laminates are translucent, although up to 90 per-

cent light transmission can be achieved in a 1/16 inch to 1/8inch FRP laminate through the use o special resins and mat.

However, an opaque laminate can also be made by in-corporating pigments and llers in the resin. Color can bemolded into the product so that painting is unnecessary.

8. WEATHERING PROPERTIESThe outdoor weatheringproperties o FRP are generally good. However, there is acertain susceptibility to ultra violet rays which require thatultra violet absorber be specied or translucent laminates.Normally, UV absorbers are not required or gel coat be-cause the pigments and llers act as absorbers. In addition,

all exposed laminates should either have a gel coat or aglass suracing mat specied or the exposed suraces toprevent ber blooming or surace exposure o the bers.See also the chapter on Weathering.

9. POLYESTER SHRINKAGEPolyesters will shrink ap-proximately six to nine percent by volume. A glass reinorcedlaminate may have only 0.25 percent linear shrinkage.

FRP COMPOSITES: General Properties o FRP Composites Resins



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FRP COMPOSITES: Fabrication oFRPComposites

1. INTRODUCTIONFiber reinorced plastics can be ab-ricated using a number o processes. Some examples areas ollows:

Hand layup lamination Sprayup lamination Continuous lamination Resin transer molding and numerous varia-

tions o this process Inusion Pultrusion Fiber placement Spin casting

Filament winding Compression molding Injection molding.

This book will not cover each o these processes in depth.However, three main categories o these processes will beexamined urther. These categories are:

Open molding Low volume closed molding Compression molding.

A brie description o each o these process categories ol-lows. Table 1 shows a comparison o the major eatures o

each category.2. PROCESS DESCRIPTIONS

A. Open MoldingOpen molding is the simplest andmost widely used process to produce FRP parts. Openmolding is done in ambient shop conditions. The molditsel is generally abricated rom FRP and is one-sided.It can be male (part is molded onto) or emale (part ismolded into). The cosmetic surace o the part is abricat-ed next to the mold. The back side o the mold is open.

In contrast to many other abrication processes wherethe exterior coating is applied ater the main structure othe part has been built, open mold parts are built romthe exterior to the interior. The rst step in open moldingis to apply the gel coat (the exterior coating o the part) tothe mold. The remaining layers o the laminate design,which will include some but not all o the ollowing, backthe gel coat:

1) Barrier CoatAn additional coating that is ap-plied behind the gel coat. A barrier coat im-proves part cosmetics, reduces cracking andimproves osmotic blister resistance in marineparts.

2) Skin LaminateA relatively thin glass berreinorced laminate abricated behind the gel

coat. Skin laminates improve cosmetics andosmotic blister resistance.

3) Print BlockerA sprayable syntactic oam ma-terial used behind a skin coat to improve lami-nate cosmetics.

4) Coring MaterialsLight weight materials usedto build part thickness and stiness withoutadding weight.

5) Bulk LaminateThe main portion o the lami-nate that provides most o the structural prop-erties.

Glass ber reinorcement used in skin and bulk lami-nates can be applied by hand layup or sprayup. Handlayup is used when applying roll good reinorcementssuch as chopped strand mats, and textile constructionsthat are stitched or woven. Brushes, rollers or wetoutguns can be used to apply the resin.

Sprayup is used when the laminate reinorcement ischopped roving. Chopped roving and catalyzed resinare sprayed onto the lamination surace with a choppergun. The glass is wet out and compacted with lamina-

In This Chapter1. Introduction2. Process Descriptions

3. Process Selection

Part Three, Chapter IV

Table 1. PROCESS COMPARISONPart Characteristic Open Molding Low Volume

Closed Molding

Compression Molding

Maximum Part Size Any Size Any Size Up to 100 Square Feet

Factors Limiting Part Size Mold and Part Handling Mold and Part Handling Press Size

Part Surace One Side Two-Sided, Smooth or Textured Two-Sided, Smooth or Textured

Part to Part Consistency Fair Good to Excellent Excellent

Cross Section Completely Variable Better i Uniorm Easily Varied

Number o Parts Per Year


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FRP COMPOSITES: Fabrication o FRP Composites

tion rollers. Hand layup and sprayup can be combinedwithin the same part or laminate.

The part size or open molding is restricted only by partand mold handling considerations. Open molding is la-bor intensive in comparison to some other processes.Part-to-part consistency is dependent on operator skill

and is generally variable. Emissions rom open moldprocesses are signicant and are regulated by FederalNESHAP standards and, in some cases, State and Localregulations.

More detailed inormation on open molding can beound in Part Four o this book.

B. Low Volume Closed MoldingThe category olow volume closed molding processes includes pro-cesses in which liquid resin is transerred into a closedcavity mold containing reinorcing materials. Over time,many variations o low volume closed molding process-

es have evolved. Some examples are:

Vacuum inusion

Seamann Composites Resin Inusion Man-uacturing Process (SCRIMP)

Conventional RTM

Light RTM (shell laminate RTM)

Silicone bag RTM

Closed Cavity Bag Molding (CCBM)

Multiple Insert Tooling (MIT) RTM

Zero Injection Pressure (ZIP) RTM.

Parts abricated using these processes may or may not

have gel coat on the exterior surace. For parts abri-cated with gel coat, the gel coat is applied to one hal othe mold using the same techniques as used or openmolding. The mold is then loaded with reinorcing ma-terials and closed. Catalyzed resin is transerred intothe mold. Ater the part is suciently cured, the mold isopened and the part demolded.

The part size or these processes is limited by mold andpart handling considerations. Part-to-part consistencyis better than with open molding due to less depen-dence on operator skill. Also, two-sided cosmetic parts

can be produced. Emissions rom these processes arestill regulated; however, they are much lower than withopen molding due to the closed portion o the process.Emissions rom the gel coat application, i used, are thesame as or open molding.

More detailed inormation on low volume closed mold-ing can be ound in Part Five o this book.

C. Compression MoldingCompression molding isanother closed molding process that uses clampingorce during mold closure to fow a pre-manuacturedcompound through a mold cavity. A hydraulic press

generally provides the clamping orce. Compressionmolds are generally made rom chrome plated tool

steel. Sheet molding compound, bulk molding com-pound and wet molding compound are examples opre-manuactured compounds.

I an external coating is needed on a compressionmolded part, it is generally post applied; however, in-mold coatings are available. Part size is limited by press

platen size. Part-to-part consistency is excellent. Emis-sions rom compression molding are still regulated;however, they are much lower than with open moldingdue to the closed nature o the process.

More detailed inormation on compression moldingcan be ound in Part Six o this book.

3. PROCESS SELECTIONThe best process to use or ab-rication o a specic part may be obvious. However, whenthe best process is not obvious, process selection is best ac-complished through a process trade study.

A process trade study involves comparing the part abrica-

tion costs and part perormance actors or a specic partabricated by various processes. Part abrication costs in-clude but are not limited to equipment costs, tooling costs,material costs, and labor costs. Part perormance actorsare dependent on the specic part being studied but caninclude, weight, strength requirements, and appearance re-quirements. Emissions o Hazardous Air Pollutants (HAP) orother regulated materials vary by process and may also ac-tor into process selection. An example trade study ollows.

The subject part is rom the deck o a run-about boat. It is ahinged hatch cover that provides access to an under-deckstorage compartment or cooler. The step ace eatures anon-skid prole on the external surace. The step ace com-prises glass skins over oam lled honeycomb core. Thepart measures 11 inches by 25 inches with a 1.5-inch tallperimeter fange. The design criteria include an impact o300 pounds rom a three-oot elevation. The part is shownin Figure 3/IV.1.

Processes considered in the trade study were open mold-ing and several low volume closed molding processes in-cluding vacuum inusion, silicone bag RTM, light RTM, andconventional RTM. Equipment costs, tooling costs, materialcosts and labor costs were calculated or each process on a

per part basis. Costs are based on typical values in the year2005, and are presented as relative costs with open mold-ing at 100 parts produced as the baseline.

The number o parts to be produced varied rom 10 to 9,000.Parts were to be produced over a three-year time rame withan equal number o parts per year. Process trade study costresults are shown in Figure 3/IV.2 on the ollowing page. Thecost per part decreases as the number o parts producedincreases. However, the amount o decrease depends onthe process, meaning that dierent processes are the mostcost-eective at dierent production rates.

Conventional RTM is not a cost-eective option or hatchcover production at production run sizes o less than 1000



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parts. For production run sizes greater than 1,000 parts thisprocess becomes competitive with light RTM, but does notbecome cheaper than light RTM even at production run siz-es o 9,000 parts due to the need or a gel coated surace.

The cost comparison could be dierent or large productionruns o a non-gel coated part.

While competitive with light RTM, silicone bag RTM is neverthe cost-eective process or hatch cover production. This isdue to the cost o the materials needed to abricate the sili-

cone bags. However, silicone bag RTM can be an excellentprocess selection or parts with closed contours that are noteasily abricated by other processes.

Light RTM is the low cost process or hatch cover productionat production run sizes greater than 100 parts.

Vacuum inusion is competitive with open molding as thelow cost process or hatch cover production runs o less than100 parts. At higher production rates vacuum inusion is notcost-eective due to the cost o the consumable materials(vacuum bag lm, sealant tape, etc.) needed or each part.

Open molding is the low cost process or hatch cover pro-duction runs o less than 100 parts. But is not cost-eectiveor production runs greater than 100 parts.

Overall process trade study results including part appear-ance, strength, cost and emissions, or the hatch cover areshown in Table 2.

Use o closed a closed molding process reduces emissionsby 50 percent in comparison to open molding with low VOCmaterials. The emissions dierences as well dierences inpart appearance could infuence process selection or hatchcover production.

This trade study is provided as an example o the type oevaluation that can be done to make an inormed decisionon process selection. The conclusions reached are not validor all part types, sizes, complexity and specic combina-tions o labor, material and capital costs.

FRP COMPOSITES: Fabrication o FRP Composites

Figure 3/IV.1Trade Study Hatch Cover

Table 2. COMPARISON OF RTM PROCESSESProperty Open Molding Vacuum Inusion Light RTM Silicone Bag RTM Conventional

RTM

Part Appearance Part back side isrough

Part back side ismatte

Part back side issmooth

Part back side ismatte

Part back side issmooth

Strength Acceptable Comparable toopen molding

Comparable toopen molding



Cost EectiveProduction Run Size


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OPEN MOLDING: Introduction

In Part FourChapter I: IntroductionChapter II: Conventional Gel CoatChapter III: Specialty Gel CoatsChapter IV: Vinyl Ester Barrier Coats

Chapter V: LaminationChapter VI: Sprayable Print BlockersChapter VII: Field Service

Open molding is the most widely used process or abrica-tion o FRP parts. The basic open molding process involvesapplying gel coat to a one-sided mold, and then backing thegel coat with the remainder o the laminate design. Openmolding is generally done in ambient conditions. Some othe materials commonly used in open molding are:

Gel CoatThe exterior coating o the part,the gel coat serves several purposes. Duringmanuacturing, the gel coat protects the moldrom abrasion and chemical attack. It also pro-vides a releasable coating. Ater manuacture,the gel coat becomes the exterior cosmeticcoating o the part, and also provides protec-tion against water exposure and weathering.Most, though not all, open-molded parts aregel coated. Examples o non-gel coated openmolded parts include spas, bathtubs, andshower stalls where acrylic or ABS is used inplace o gel coat as the exterior coating.

Barrier CoatAn additional coating that is ap-plied behind the gel coat, the barrier coat im-proves part cosmetics, reduces cracking, and

improves osmotic blister resistance in marineparts.

Skin LaminateA relatively thin glass berreinorced laminate abricated behind the gelcoat, the skin laminate is specially ormulatedto cure completely as a thin laminate and toimprove part cosmetics. Skin laminate resinsare also typically ormulated with high peror-mance polyester or vinyl ester polymers to im-prove osmotic blister resistance.

Print BlockerA sprayable syntactic oam ma-terial, the print blocker is used behind a skinlaminate to improve laminate cosmetics.

Coring MaterialsThese light-weight materi-als are used to build part thickness and sti-ness without adding weight.

Bulk LaminateThis component is the mainportion o the laminate that provides most othe structural properties.

The ollowing chapters cover the various gel coat and resin

materials used in open molding, application techniques,troubleshooting guidelines, and eld service issues.


Part Four, Chapter I


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OPEN MOLDING: Conventional Gel CoatMaterials

In This Chapter1. Introduction2. Materials3. Quality Control

Part Four, Chapter II.1

1. INTRODUCTIONA conventional gel coat is a pigment-ed, polyester coating that is ormulated or use in ambienttemperature, open mold processes. The gel coat is appliedto the mold surace and becomes an integral part o the n-ished product. The gel coat provides a durable, cosmeticallyappealing nish and also protects the part rom environmen-tal exposure.

2. MATERIALSConventional gel coats are ormulatedrom several components including the polymer, reactivemonomer, pigments, llers, thixotropic agents, promoters,inhibitors, and specialty additives. Proper selection o rawmaterials and the amounts o those materials will result in a

gel coat that has good spray characteristics and will not sagon the mold when applied at the recommended lm thick-ness, typically 18 2 mils wet. The gel coat should cure in areasonably short period o time to meet production require-ments andwhen properly curedwill oer good color re-tention with resistance to water, weathering and other envi-ronments.

A. PolymerPolyester polymers can have a widerange o properties depending on the raw materials(acids and glycols) used to produce them. All polyesterpolymers have an unsaturated acid component, typically

maleic anhydride. The unsaturation in the polymer pro-vides a site or reaction with the monomer, also knownas cross-linking. Polyester polymers used in gel coatsalso have a saturated acid component. In some casesthe saturated acid has been orthophthalic acid, but themost commonly saturated acid is isophthalic. Polyesterpolymers containing orthophthalic acid have been usedin gel coats or general purpose applications. Polyesterpol

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53741251 Fiberglass Composites Application Guide