development of uv-cured sealing coatings for balsa ...€¦ · phil barker, matthew kennedy and...
TRANSCRIPT
-
DevelopmentofUV-curedsealingcoatingsforbalsa-minimisingpost-appliedresinabsorptioninwindturbineblademanufacture
Phil Barker, Matthew Kennedy and Peter Gillies
-
Program for today
• Project background • UV Curing background • Raw materials characterisation
– Quantitative 13C NMR • Balsa as a substrate • Understanding the real problem • Lab/line UV curing correlation • Possible solutions • New formulations and results • Impact on turbine blade manufacture • General information about co-operative funding for research
projects or product development.
SCAA 2019 2
-
So what did A&I want us to do??
SCAA 2019 3
-
Then….
SCAA 2019 4
UV cured coating to seal the balsa
www.diabgroup.com
Minimise finish resin uptake
Blades as light as possible
-
Plan
• Characterise coatings raw materials in current product offer • Characterise substrate • Understand UV curing production line in Moss Vale • Optimise photoinitiator package • Optimise new formulation • Proof of concept
• Line trial on UV curing production line in Moss Vale • Characterise product of line trial
SCAA 2019 5
-
Background Watching paint dry is fun……..seriously
SCAA 2019
-
Thermal curing Watching paint dry is fun……..there are so many ways of doing it
Exit Entry
150m/min line speed
SCAA 2019
-
Background Watching paint dry is fun……..seriously
SCAA 2019
-
UV curing Watching paint dry is fun……..there are so many ways of doing it
• Ambient temperature
• 100% solids – All components react – No solvents – Fewer OH&S issues
• Significant cost benefit vs thermal curing
– Operating costs – Maintenance
• Many and varied applications
Tom Slavinsky – www.metalfinishing.com
SCAA 2019
-
SCAA 2019 10
UV curing Many unique applications already
-
UV curing Many unique applications already
SCAA 2019 11
-
UV curing Many unique applications already
SCAA 2019 12
-
UV curing Many unique applications already
SCAA 2019 13
-
UV curing Overall process
• Photoinitiator – Type I, type II
• Reactive base resin – Diacrylate
• Other stuff – Reactive diluent
• Viscosity control • Reactivity
– Synergist (with type II PI) • Radical generation
SCAA 2019
-
Substrate Characterisation - balsa Density Variation
100 mm
610 mm
1220 mm
200 mm
SCAA 2019
-
Method UV Sealing coat applied
Coated with UV sealer
SCAA 2019
-
18
Method Resin application
SCAA 2019
-
Heart of the problem Resin bleed-through
SCAA 2019 19
Tracheids, rays and sap channels
-
Resin bleed through
— Each resin spot corresponds to an open sap channel
— The sealing coating does not seal !
— As the channels are 200µm (±50), the sealer cannot bridge this gap.
— This picture was a ‘good’one !!
The Problem Underneath after sealing and resin application
Balsa
Sealing coat
Post-applied resin
Sap Channel – Circular
150-250 µm Tracheids – Hexagonal – 30-70 µm
Ray Cells – Rectangular – 13 µm
SCAA 2019
-
Visually Differing coating masses (in duplicate)
Qualitatively, resin bleed-through shows that higher coating mass decreases resin absorption
Sealer coating mass
Resin bleed
From this background work, we developed two methods for estimating resin bleed
through…..
SCAA 2019
-
Method 1 Epoxy film build
Higher sealing coat mass shows increased epoxy DFT
100 mm
200 mm
Scrim
Film buildmeasurement
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
21 26.5 43.5 53.5
VC6 Standard Fi
lm B
uild
(mm
) Coating (g/m2)
SCAA 2019
-
Method 2 Resin absorption
Resin absorption calculated by mass gained shows higher coating mass decreases resin absorption
0
100
200
300
400
500
600
700
800
21 26.5 43.5 53.5
Standard Formulation R
esin
Abs
orpt
ion
(g/m
2 )
Coating (g/m2)
Blade manufacturer in-house method
— Weigh sealed balsa piece (a)
— Apply Epoxy and cure
— Carefully sand epoxy back to balsa surface
— Reweigh (b)
— b – a = absorbed resin mass
SCAA 2019
-
Novel formulation concepts Lab evaluation
• Base formulation : epoxy acrylate, diluent, synergist, PI package (BP + Irgacure 184) • Optimise PI concentration • Replace 184 with BAPO – type initiator
• New concept : employ UV-formulation compatible materials (some reactive, some not) – Matting agents – Texturing agents – At unusual concentrations – Block sap channels
SCAA 2019
-
Eureka moment ! Incomplete drawdown of #2+B
SCAA 2019
-
Microscopy Method development
Unsealed balsa Sap Channels clearly visible
Contrast is poor Which channels are filled? Which channels are empty?
Look closer
SCAA 2019
-
Microscopy Close up of the interface
SCAA 2019 30
-
Microscopy Method development
Platinum sputtering of whole surface
Contrast is improved Can see full and partially filled channels
Look closer
Now put on your 3D specs !!!
SCAA 2019
-
Microscopy Method development
SCAA 2019
-
#2 + B
SCAA 2019 33
Sealing coating applied
Post applied resin on top
Target no resin bleed-through
Sap channel should be EMPTY
Now put on your 3D specs !!!
-
#2 + B
SCAA 2019 34
-
No sealant
SCAA 2019 35
No sealing coating
Post applied resin on top
Resin bleed through
Sap channel should be FULL
-
No sealant
SCAA 2019 36
Top of column
Resin fills sap channel
Air bubble
Resin bleed through
-
No sealant
SCAA 2019 37
Bottom of column
Resin plugs sap channel
Resin bleed through
Sap channel is FULL
-
Sap Channels sealed (yippee!!) But these were laboratory prepared samples now we must scale up
20cm x 10cm 120cm x 60cm
50ml 10L
SCAA 2019
-
Limited by constraints and variables…
• Balsa Sheets 120mm x 60mm
• Only 20 sheets available !!!!
• Decided upon 4 formulations, to produce 5 sheets of each at different coating masses
• A&I base formulation, but with reduced photoinitiator (4%)
• Matt1 – A&I base (4% photoinitator) with 1% (mass basis) B (+ reduced reactive diluent)
• Matt2 – A&I base, 4% optimised photoinitiator package, 0.5% Additive B + 0.5% additive C
• Matt3 – A&I base, 4% optimised photoinitiator package, 1.0% Additive C
• Scale up all formulations from 50g to 10Kg
• Coated Sheets to go to composite company in Sweden for testing
Plan for line trial
SCAA 2019
-
Production line trial June 16th
SCAA 2019
-
Production line trial Line overview
SCAA 2019
-
Production line trial Applicator with nip feed
SCAA 2019 42
-
SCAA 2019 43
Production line trial Balsa sheet going from applicator to 1st UV station
-
Production line trial June 16th
Clear sample labelling on all 4 edges
18 sheets out of 20 for Sweden
We retained 2 for our testing
‘Matt 3’ 24g/m-2
SCAA 2019
-
Promising after resin application Comparison with VC6 at 40g.m-2
Original system shows considerable resin bleed
Clearly reduced resin bleed from ‘Matt 3’ at similar coating mass
Must do the microscopy to confirm
Original A&I system ‘Matt 3’ system
SCAA 2019
-
Promising after resin application Section and Pt sputter
Post-applied resin
‘Matt 3’ coating on both sides
Close up….
Now put on your 3D specs !!!
SCAA 2019
-
SCAA 2019
-
SCAA 2019
-
Blade manufacturing
Turbine blade construction
Balsa core
Resin infusion
Picture from Composites World June 2010
When our whole product sheets were tested under vacuum infusion conditions in Europe……
200g/m2
Order of magnitude improvement over uncoated balsa
SCAA 2019
-
• At least 2 reformulated systems which show no resin absorption/bleed and excellent production line application properties
• Improved photoinitiator package
• Detailed Report
• Recommendations for future work
• All in 7 months [official project timeline 6months (+2)]
What have we delivered ?
SCAA 2019
-
Significant result for blade development Research in USA
SCAA 2019 53
All-glass Baseline Blade: 114 ton weight
Carbon Design Studies: 74 ton weight
Advanced Core Material: 59 ton weight
-
Funding Innovation Connections Program
• Bruce Thomson Business Development Manager
• Professor Di Jolley
• Phil and Matt
SCAA 2019
-
Funding State government programs
Supporting business in New South Wales
Eligible businesses can use a TechVoucher to: • seed a research project in partnership with a BBIP delivery partner • support a research project that will lead to an application for an Entrepreneurs' Infrastructure Programme Research Connections or Accelerating Commercialisation, or other similar scheme • fund access to research facilities and equipment such as electron microscopes, medical imaging, e-research supercomputers, nanofabrication, marine and climate infrastructure, and other BBIP delivery partner facilities • fund product or process design activities, such as engineering or technical design expertise to determine prototype structure, function and/or materials • access technical assistance • trial production runs or processes to demonstrate technical concepts • validate or demonstrate technical capabilities of a product, process or technology • fund toxicology studies on materials you have invented, or wish to incorporate into a new product.
TechVouchers
www.industry.nsw.gov.au
SCAA 2019
-
Funding Australian Research Council Linkage Scheme
3-year funding for major research project arc.gov.au
• Must be in an area of national interest/priority • Rigorous selection process
SCAA 2019
-
• Enthusiasm and support of Peter and the team at A&I Coatings
• Professor Dianne Jolley (now UTS) for her astute mentorship, management and communication skills
• Head of School of Chemistry and Molecular Bioscience
• To all the Conference organisers for inviting me to speak
• To all you attendees – Thank you.
Acknowledgements
SCAA 2019