Cost Effective Solutions: More Than Just Paint

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Dual Cure UV Sealer Review
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DynaSeal Sealer What is it?

• UV / Thermal Sealer for SMC
• UV portion of cure seals SMC surface before it is
  exposed to elevated temperatures
• Seals SMC surface to reduce paintability problems
• Porosity
• Outgassing
• Popping
• Improves first-run output at both part
  manufacturer and auto manufacturer

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UV / Thermal Sealer for SMC

• Prevents porosity-induced defects
• Thermal cure follows UV irradiation for final
  properties
• Conductive Non-conductive formulations
• Positive Enhancements
• Compliant VOC
• One coat coverage
• Excellent surface appearance
• Increased first run capability

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DynaSeal Sealer for SMC

• Two-component system
• Solution to porosity on SMC
• Initial sealing properties provided by the low
  temperature UV film formation
• Ultimate performance provided by the final
  thermal cure
• Without UV cure parts would still pass all
  automotive specifications

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DynaSeal Sealer Dual Cure Process
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Advantages of UV / Thermal Approach

• No need to mask or shield areas that get
  overspray
• Over spray will cure with a hybrid system
• Field Performance is still achieved without UV
  Cure
• Coating will accept other coating layers after
  cure
• UV light to seal porosity can be directed at
  critical areas only

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Composite Materials

• Recent advancements in SMC Sealers make usage
  more attractive.
• Upgraded materials make SMC more cost effective.
• Improved First Run Capabilities justify material
  equipment expenses.
• UV Sealers with improved SMC can exploit full
  potential of SMC usage on cars and trucks.
• New Flexible DynaSeal (UV Sealer) further
  enhances performance.

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Hybrid UV Sealer Process
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Performance ComparisonDynaSeal Sealer vs.
In-Mold Coating P225 Panel Comparison
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DynaSeal Sealer UV / Thermal Sealer for SMC
History Future

• Status
• ITW Ransburg trials Toledo Ohio summer and fall
  of 2000
• First customer Meridian (Kansas City)
• First production trials at Ford KC February 2001
• Ford KC plant launch September 2001 - P225 box
  side outers supplied to Ford plant with UV sealer
  (over 1100 trucks per day 2200 parts per day)
  
• Over 400,000 Ford F150 pickup truck on the road
  with DynaSeal
• Over 40,000 Ford Lincoln Aviator (80,000) Fenders
  for Ford St. Louis
• Successful trials with other automotive parts
• Approvals at other customers complete

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Current Production Parts With DynaSeal
Aviator
F150 Super Crew
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DynaSeal FX New Improved - Flexible

• SMC popping generated by microscopic porosity
  plus Pre Post Stressing of Parts
• DynaSeal Effective for pre-stressing
• Cracks or porosity from molding handling prior to
  sealer
• Sealer elongation 2-3
• DynaSeal Flexible Effective for both Pre Post
  stressing
• Post stressing occurring from handling after
  sealer application
• Sealer elongation 20

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DynaSeal Crack in SMC Post Crack
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SMC Crack at Knit line
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Porosity of panels stressed prior to Sealer
application
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Porosity of panels stressed after Sealer
application
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Elongation Versus Film Build
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Rigid vs. Flexible Sealer
Rigid
Flexible
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Following the Photoinitiator Decay
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This matches the published spectra of Lucirin
TPO-L which makes up 90 of the PI package
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Understanding standard curing conditions
Photoinitiator is 100 consumed under standard
curing conditions
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Understanding the Kinetics of PI Decay
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lnA -k(dose) lnA0 Integrated form for
first-order kinetics
PI decay is first order
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Photoinitiator / Post Cure Conclusions

• At a nominal cure of 3 J/cm2, the photoinitiator
  is 99.7 decomposed.
• There is little or no photoinitiator left after
  cure to impact UV transmittance or to impart any
  post reaction.
• Reaction of photoinitiator with UV light is a
  first order reaction with respect to light energy
  (number of photons)

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Bake/Dosage Window Definition

• How do Lamp Type, Irradiance Level, and Time
  impact the cure window? What failure modes would
  we expect with under or over exposure?

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UV Dosage Window Target 3.0 J/cm2 Range 2.5
to 6.0 J/cm2 Dosimeter EIT Power Puck (UVA
UVB) Bulb H or D type
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Irradiance Profile for UV Cure
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Dosage Variations for Dual Cure Clearcoat
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CC Cure for Dual Cure Clearcoat versus Dosage
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UV Dosage Window

• With high intensity lights, the cure mechanism
  depends on total UV dosage (J/cm2) only
• Peak Irradiance level (.5 to 2.8 W/cm2),
  time/line speed (6 to 50 ft/sec.) and number of
  passes can be varied without the cures
  dependence on total dosage changing.

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Oxygen Inhibition

• With high intensity lights radical are formed
  faster than oxygen can scavenge them.
• DynaSeal uses higher molecular weight
  constituents than a typical 100 UV cure system.
• This combined with the fact that 98 of the
  solvent has been flashed out means that oxygen
  diffusion into the film is very slow into the
  high viscosity (tacky) film that remains.

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UV Cure Mechanism

• Initiation
• PI UV ? PI
• PI ? R
• R CC ? R-C-C
• Propagation
• R-C-C CC ? R-C-C-C-C
• Termination
• R R ? R-R
• R O2 P ? R-O-O-P

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Acrylate Cure at Top of DynaSeal Film
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Acrylate Cure at Bottom of DynaSeal Film
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Film Properties vs. UV Dosage
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Film Properties vs. UV Dosage
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UV Cure Window

• We know that UV from sunlight contributes to the
  degradation and eventual failure of coatings in
  the field. Can prolonged exposure to UV lamps
  during the cure process initiate some of the same
  type of chemical bond breakages that eventually
  take place in the field?

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Overlay of Sunlight, WOM and H-Bulb Spectra
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Photo-oxidation of DynaSeal Primer with UV Cure
Dosage
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Short Time WOM Exposure of DynaSealPhoto-oxidatio
n
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Photo-oxidation of Clearcoats
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UV Cure Window

• Photo-oxidation does occur, but to a very limited
  extent
• Equivalent to about 2.7 hrs of WOM exposure
• Not enough to cause significant polymer
  degradation
• There is no observed failures with over exposure
  of UV up to 12 J/cm2
• Porosity will fail at less than 0.5-0.8 J/cm2.
  Other Physical properties will pass.
• UV Dosage Target and specification window
  provides a very robust process with a wide dosage
  range with no change in chemistry and physical
  properties.
• The Bake Window chart is applicable to all UV
  dosages in the specified range

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UV Absorbance/Transmittance Questions

• Does Dynaseal meet durability requirements in the
  absence of primer/surfacers?

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UV Transmission Spectrum of P35AM758
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UV Transmission Spectrum of P35AM758
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WOM Exposure SMC with DynaSeal, with and
without Primer Surfacer
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WOM Exposure Ecoat, DynaSeal, and Control SMC
primer w/out Primer Surfacer
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Durability Conclusions

• Light can be transmitted through sealer film
• Weak Film and Thin film Exposure data show that
  SMC with Sealer is at least as durable as SMC
  primer or primer surfacer and considerably better
  than E-coat
• With other substrates like RIM or carbon fiber
  there may be issues with exposure with thin or
  weak film topcoats.
• In general a minimum transmittance specification
  should be maintained for the topcoats

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Summary

• Dual Cure (UV Thermal) sealer provides a path
  to eliminate porosity-induced defects such as
  paint popping
• Two years production experience on 3D car parts
• Flexible version developed and trialed to
  eliminate defects from post-sealer stress
  cracking
• Laboratory data provide a scientific knowledge
  base for
• Dosage / Line speed recommendations
• Cure window recommendations
• Equipment choice
• Durability characterization