Epoxies and Plastics in the ITK--safety issues--

Project Engineer ITK-Strips: Marcel Vreeswijk

Use of Epoxies in the Itk-StripsProblem and context• epoxies (and plastics) turn out not to comply with CERN safety rules for use in the ATLAS pit.

• Triggered by check of materials by Sigi and now Laetitia based on document IS41 https://edms.cern.ch/ui/#!master/navigator/document?D:1070560327:1070560327:subDocs

• Document last revision Nov. 2005 !!! It is not easy to use. No details on modern materials. Cyanate Ester based adhesives not described at all. These are usually intrinsically fire retardant; unclear if these comply.

• NO recent use case: for instance, IBL materials appear never to have been reported to ATLAS safety crew.

Consequences:• NOW: this affects directly the strip Endcap (pass PRR june 2019). Nikhef stopped the production of CF rings.

Company for EC Inner Cylinder jumped out: ‘’come back when you know what you want; we start other project now till summer 2020’’ delay, sofar mild and I think still OK (because overall schedule moved)

• All commercial available epoxy CF elements (pultruded and woven ribs, rods, sheets) need to be made from scratch. Winding of CF rings for EC Wheels need to be redesigned (and tested/validated!!!) for autoclave curing. >>1 year delay + costs

• Several parts of stave/petals also use ‘normal’ epoxies Delay+costs.• If even cyanate esters need to be formally tested on flammability, smoke-toxicity and smoke-density costs (small

delay, provided that these pass)

Marcel Vreeswijk, 23 Oct 2019

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Where in the ITK-strips are flammable materials applied?

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Bulkhead

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Strip endcap bare structure6 wheels ~25kg CF(60%)/Epoxy (40%) 1 Inner Cylinder ~3kg CF/Epoxy1 Stiffener disk CF foam(12kg) with CF facesheet+epoxy (5kg)Spacer Rods: ~1 kg CF/EpoxyService Trays: ~4kg CF/Cyanide Ester or Hysol 93962 Beams with rollers ~4kg CF/EpoxyTorlon items (1kg) fixed with Epoxy (0kg)

Petals:Facesheets CF/Cyanite Ester est 10kgCF Foam/Honeycomb/ + 6kg Epoxy Torlon itemsTitanium tubes inside2 Cupper tubes each 72mm, Mass = 3,3 gram. 1kgC channels of CF/Epoxy (40%)

Wheels:Rings contain Epoxy Resin L: Epoxy resin with as reaction product bisphenol AEpoxy harder W300: slow curing harder product polypropylenediamineBlades: Bisphenol Epoxy with honeycomb of Nomex.

Stiffener Disk:Carbon Fiber foam (brand: CFOAM) or Airex foamCF facesheet + epoxy bisphenol

Service trays

Petals

Blades

Wheels(=rings+blades)

Rings inner/outer

Stiff Disk

Inner cylinder

NOTE: the EC CF structure is not in contact with electronics. No power cables are in enclosed modules or whatsoever.

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Strip Barrel4 shells CF/Cyanide ester estimate 30kgInterlinks CF/Cyanide ester est 2kgBrackets fixed with Epoxy???Supports to OC CF/Epoxy???Titanium bolts

Staves:Facesheets CF/Cyanide Ester est 10kgCF Foam/Honeycomb/ and 10kg Epoxy Titanium tubes inside.Locking points Torlon???C channels with 40% epoxy

InterlinksCylinders(staves not shown)

brackets

OC supports

staves

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Summary of Epoxies/Plastics and their use in Itk-stripsAdhesive Flammable? Where/what Typical ITK

strips (rough est.)

ResinL/W300 Yes, tested at Nikhef Rings of of EC wheels 10kg

ResinL/+??hardener Yes, tested at Nikhef Stiff. Disk. And EC inner cylinder 15kg

General (Bisphenol) epoxy Yes, tested at Nikhef Spacer rods. Face sheet blades. C channelblades/petals, roller-beams

20kg

Hysol AE 9396 Yes, tested at Nikhef Inside petals/Staves 10kg

Polaris PF7006A / Hardener 3-Diethylaminoproplymin

Unknown Powerboard to sensors 1kg

SE4445 gel Unknown Modules to petals 1kg

EX1515 (cyanite ester) Not easy? based on literature

Facesheet petals/staves 20kg

RS3 (cyanite ester) No, based on test at Nikhef Outer Cylinder and Barrel Cylinders. (perhaps swith to EX1515

150kg

PolyEthylene Yes (also dripping) Outer Cylinder inside 300, outside 800 1100kg

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If Epoxies are not allowed in the Itk EC strips,• Solution for Epoxy in CF-EC strips could be: continuously flush ITk volume with Nitrogen. Also

during shutdowns. (oxygen deficiency should be monitored). OR, forbid any electronic components are on, when flushing with dry air in shutdowns.

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To put epoxy use in CF laminates in perspective:• There is <100kg Epoxy foreseen in CF structures• There >1000kg polyethylene on the Outer Cylinder.• The muon chambers contain 500kg (or more) epoxy• The current IBL/SCT detector is full with epoxies. We just replace those epoxies

Why focus on <100kg epoxy in CF, while surrounding area contains >1000kg of similar materials?

We need a sensible budget on Epoxy-adhesives to continue the Itk effort.

PART II:

search for fire resistant epoxiesrequirements EC strips:

-cure at Room Temperature;-low viscosity.

requirements IS41:-contains fire retardant;-no halogens.

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Fire retardant epoxies at room temperatureSeveral experts and companies (Araldite, Huntsman, Lijmacademie) were contacted by mail/phone showstopper is: NO HALOGEN FREE fire retardant

Several long days were spend on the product websites, mostly aerospace application see next page with some candidates

Conclusion: all room temperature curing epoxies have high viscocity or contain halogen showstopper

Note: even if alternative fire save Epoxy is found, delays are unavoidable:• Redo irradition tests;• Remake some prototypes, redo some mechanical and cooling tests. >1year

work

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Epoxy Tempcure

time cure time open Tg or Tservice FR or FST Visco Strength-shear

LOCTITE EA 9364FR AERO(ALSO KNOWN AS Hysol EA 9364FR)

20 1day handling5days

90 Up to 70 FST 8000 35MPA

EPIBOND® 8000 FR A/B Adhesiv

20 >days 70 Up to 70 FSR very low halo. Thixotropic 26 Alsofor extrusion

Araldite® 1570 FST A/B 20 2days 140 -55 to 60 FST 2000?Thixotropic

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DUOPOX AB8390 20 1day/7days 1h 50g30min 100g

92 FST Pasty/high visco

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Epibond® 1559 A/B 20 day 10min high FST 80000? 20

Araldite® FST 40002 / 40003 100 100min long FST 65

Sicomin SR1126 + 8202 (instelbaar)

20C+30C 4dagen 30min-2uur >60 FST 1250 25

FlameX 9600 150

Cellobond_Resins_Phencat 60

Coating SC FW 16 - FireWall16

20 day - hi FST Thixotropic

Coating cellobond ULF GC84-500_D

20 day FST

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Cyanate esters

Most have good fire properties uptorelatively high temperatures.

Disadvantage for many applications: cure at high temperatures ~150degC.

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