Improving the Cosmetic Quality and Finished Durability of Glass Fiber Reinforced Composites

ARMORCOTE®ArmorGuard®

-

Cosmetic Quality

Products with the best cosmetics are perceived to be higher qualityare more likely to be purchasedcommand a higher selling price

Consumers expectations continue to evolve

This issue effects all composite manufacturers Open Molding Closed Molding

RTM, Infusion can have greater surface distortion than open molding Across Markets

Marine Transportation General

-

Defining Cosmetic Quality

Cosmetic surface flaws go by many different names: Print-though, glass print, woven roving checksDistortion, waviness, wrinklesHeat lines, heat distortion Orange peel, dimples, Pock marksCore print, balsa print

All of these terms describe a visible flaw in the smoothness of the surface of a finished fiberglass part.

These flaws are usually only cosmetic in nature and rarely disrupt the underlying structure integrity.

-

Sources of Cosmetic Flaws

ToolingEvery flaw in the tooling is transferred to the part.

ShrinkageResins and gel coats shrink when they cureThermal Contraction

Thermal Distortion

-

Linear Shrink Mold Linear Shrink Mold with Uncured UPR

Linear Shrink Mold with Cured UPR

UPR has significant shrinkage.

Shrinkage of Neat Unsaturated Polyester Resin

-

Cure Shrinkage

While the gel coat stays in contact with the mold the shrinkage is driven to the back side.

If cure continues when the gel coat is off the mold shrinkage occurs on both front and back sides.

Pre-releasePost cure

Fibers do not shrink

Resin shrinks around fibersGel Coat shrinks

Reinforced layers and unreinforced layers shrinkage different amountsDifferential shrinkage can result in warpage

-

Thermal Shrinkage

All items expand and contract with changes in temperature.

Rates of expansion or contraction are different for different materials.

Temperature changes cause stresses.

The temperature at which the resin solidifies has no thermal stress, or the stress-free temperature.

High exotherm causes high stress-free temperatures.High stress-free temperatures cause high thermal stresses and contraction (shrinkage) when it cools to ambient temperature.

Worst thermal case is outdoor winter storage.Low exotherm minimizes thermal stress, contraction (shrinkage).

-

Thermal Distortion:

Polymers used in resins and gel coats have a glass transition temperature (Tg)

Near and above the Tg polymers lose some of their stiffness and may warp/distort due to stress relaxation.

Happens even when fully cured

The higher the Tg of the polymer the higher the temperature must be for the stress relaxation to occur.

-

Improving Cosmetics

Minimize ShrinkageLong, slow cureLow exotherm to minimize thermal stresses.Complete cure to avoid post-cure

Long hold times on moldsThinner is better

Multiple cure steps to reach laminate thickness

ReworkAir-filing, block sanding, fairing, post-finishing, repairs, QC work, buffing, patching, re-sprays, P.I. All these have defined labor dollars in the manufacturing process.

-

The Cost of Cosmetic Quality

Example: Ski Boat Manufacturer Boats per Day 12.00 Work week, days 5.00 Number of 25 ft. boats per day 2.40 20%Number of 18-19 ft boats per day 9.60 80%

Per Boat Per Day Per Week Per Year Finish and Repair

Repair Labor Cost / Hr 25.00$

Hours Repair for Air / Distortion per Boat 6.00 $150 $1,800 $9,000 $450,000

Warranty Repair

Average Warranty Repair Cost due to Distortion per month 5,000.00$ $417 $1,000 $1,250 $60,000

Total Cost of Print and Distortion $567 $2,800 $10,250 $510,000

-

Vinyl Ester Barrier Gel Coat

Improves Cosmetics

Tough, Crack Resistant

Reduces Osmotic Blistering

Excellent Temperature Resistance

Increased Production Rate = More Parts / Day

ArmorGuard®

-

Applied Directly behind gel coat

Conventional Gel Coat Spray Equipment

MEKP Catalyst

Typical gel coat thickness (16-20 mils wet)

ArmorGuard®

-

Isolates the gel coat surface from glass fibers

Reduces/Eliminates Small-term distortionsGlass printHeat distortion Orange peel, dimplesWill not affect large issues such as warpage

ArmorGuard®

Barrier Coat

ArmorGuard® Cosmetic Improvements

-

Quantifying Cosmetics

Byk Gardner Wavescan Plus

Measures light reflectance to quantify surface quality

ResultsLong Term WavinessShort Term WavinessOverall Surface RatingDOI (Distinctness of Image)

-

Gel Coat Thickness Typical

(~15 mils) Thick

(~30 mils) Gel Coat Only 6.7 8.4 Gel Coat with ArmorGuard®

9.1 9.4

Gel Coat with VE Skin 7.9 9.3

Surface Cosmetics of Laminates With

and Without ArmorGuard®

The surface rating has the scale of 0 to 10.5. The higher the rating, the better the surface profile. Surface rating is based on the BYK-Gardner Wave-Scan ACTTM orange peel standards.

-

ArmorGuard® Tough, Crack Resistant

Comparison of Mechanical Properties for a Typical Gel Coat and a VE Barrier Coat

Typical Gel Coat ArmorGuard®Barrier Coat

Tensile Strength (psi) 7,000 11,400 Tensile Modulus (psi) 600,000 527,000 Elongation (%) 1.6 3.7 Flexural Strength (psi) 13,000 17,700 Flexural Modulus (psi) 550,000 553,000 HDT (°C) 72 105 * The test was not done at the same time. Some variations may occur due to the sample preparation.

-

0

2

4

6

8

10

12

14

16

Tou

ghne

ss, (

in.-l

b,/in

³)

Flexural Toughness at First Crack

Gel Coat (40mil) Gel Coat (20 mil) Gel Coat (20 mil) / ArmorGuard (20 mil)

ArmorGuard® Tough, Crack Resistant

Tested on gel coated laminates using typical laminating resin and 30% glass.

Gel Coat (in tension)

Load

Load Load

Flexure to First Crack Test Schematic

-

ArmorGuard® Vinyl Ester Chemistry Improves Water

Resistance

Low Water Absorption

Structure Resistant to Hydrolysis

VE’s have fewer Ester Groups

Standard Isophthalic Resin

Bisphenol-A base VE

Ester linkage shielded by methyl group

-

THIC

K SE

C TIO

NTH

IN S

ECT I

ON

46 52 92

0.5 0.5 0.1

2.0 1.2 0.0

Hours @ 100 C

Blister Rating(Thick)

Blister Rating(Thin)

92

0.2

0.0

STANDARD GEL COAT

NO BARRIER VE BARRIERVE SKIN with FIBER BARRIER + SKIN

ArmorGuard® Blister Resistance

-

ArmorGuard® Heat Resistance

Applicable to Mold Fabrication

Excellent initial cosmeticsResistant to surface changes during mold lifeTough, crack resistant

Also recommended for Closed Molding applications

Vinyl Ester Chemistry – Excellent Heat Resistance

Resistant to Thermal DistortionLimited surface change during part life

Mold Build

-

ArmorGuard® Increased Production Rate

ArmorGuard®

barrier coat can replace the skin laminate.

Faster applicationArmorGuard® Sprays on Skin laminate – Hand lay or spray application followed by rolling

Less MaterialArmorGuard® Only 20 mils needs for great protectionSkin laminate – 60-90 mils

Reduced Cure Wait TimesArmorGuard® can be applied wet-on-wet with gel coat

ArmorGuard® cures as fast as a gel coat Skin Laminate must wait for barcol development prior to bulk lamination

-

60 00 40 120 0 60

15 10 60 40 0 30 60

0 50 100 150 200 250 300

Time, Minutes

Curent Production withSkin Coat

With ArmorGard BarrierCoat

Typical (High Volume) Boat Manufacturing

Cycle Time Comparison Gelcoat Cure Stage Barrier Coat ApplicationBarrier Coat Cure Skin Coat Application and Gel Skin Coat Cure ( 20 Barcol ) Skin Coat Peak Interval (no Barcol)Bulk Lamination

Over a One Hour Time Savings per UnitUsing a Barrier Coat

Time-Zero After Gel Application

ArmorGuard® Increased Production Rate

-

ARMORCOTE® 951 SeriesAdvanced technology polyesters based gel coats

Superior weathering resistanceMinimize surface weathering and chalking

Designed for use in markets were exterior durability is criticalMarineTransportationConstruction

Good blister resistance as a stand alone gel coat. Outstanding blister resistance when used in combination with ArmorGuard®

Good flexibility for cracking resistance

-

ARMORCOTE® 951 Series Weathering

South Florida Exposure

0

20

40

60

80

100

0 3 6 9 12 Post-Buffed

Months

Glo

ss (6

0 de

g.)

ARMORCOTE 951 POLYCOR 944

White

-

ARMORCOTE® 951 Series Weathering

South Florida Exposure

0

1

2

3

4

0 3 6 9 12 Post-Buffed

Months

Tota

l Col

or C

hang

e (D

elta

E)

ARMORCOTE 951 POLYCOR 944

White

-

Summary Meet Customer Expectations for Cosmetics and Durability

Maintain Tooling

Minimize Shrinkage Low exotherm to minimize thermal stresses.Complete cure in-mold to avoid post-cure

ArmorGuard®

Vinyl Ester Barrier Gel CoatImproves CosmeticsTough, Crack ResistantReduces Osmotic BlisteringExcellent Temperature ResistanceIncreased Production Rate = More Parts / Day

ARMORCOTE® 951 SeriesAdvanced technology polyesters based gel coatsSuperior weathering resistanceGood blister resistance as a stand alone gel coat. Outstanding blister resistance when used in combination with ArmorGuard®Good flexibility for cracking resistance

-

Additional Information Sources

11 Courses Scheduled for 2011English - book, CD or on www.ccponline.com

Spanish – book or CD

Applications Guide (Cook Book)