a comparative analysis of glove permeation resistance to paint stripping formulations jeffrey o....
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A Comparative Analysis of Glove Permeation Resistance to
Paint Stripping Formulations
Jeffrey O. Stull, International Personnel Protection, Inc.
Richard W. Thomas, TRI/Austin, Inc.
Lawrence E. James, BASF Corporation
Scope
• a multiphase study was undertaken to evaluate how several types of gloves resist multi-chemical based paint stripping formulations
Background
• Paint stripping involves prolonged, continuous contact with chemical solvent mixtures
• Conventional paint strippers include:– methylene chloride, methanol, isopropanol,
acetone and toluene
• New strippers include less volatile chemicals:– N-methylpyrrolidone, d-limonene, -butyrolactone,
and dibasic esters
Background
• Relatively little information is available to guide the end user in selecting the gloves against paint strippers
• Basing glove selection on individual mixture components does not account for possible synergistic mixture permeation
Approach
• 20 different glove styles evaluated
• 7 different surrogate formulations created
• 4 different phases– Phase I: degradation screening– Phase II: continuous contact permeation testing– Phase III: intermittent contact permeation testing– Phase IV: permeation testing against selected
actual paint stripping formulations
Surrogate Paint Strippers
(I) Methylene chloride based
Methylene chloride (80%), Acetone (10%), Toluene (4%),Methanol (3%), Isopropanol (3%)
(II) Methylene chloride/acetone/toluene/methanol based
Methylene chloride (30%), Toluene (26%), Acetone (22%),Methanol (22%)
(III) Acetone/methanol/toluene based
Acetone (46%), Toluene (35%), Methanol (19%)
(IV) N-methylpyrrolidone based
N-methylpyrrolidone (75%), d-Limonene (25%)
Surrogate Paint Strippers
(V) N-methylpyrrolidone (< 50%)
N-methylpyrrolidone (50%), -Butyrolactone (28%), Exxate600 Solvent (17%), Ektapro EEP (5%)
(VI) Dibasic ester/NMP based
Dibasic ester blend (55%), N-methylpyrrolidone (36%),Dipropylene glycol methyl ester (9%)
(VII) Dibasic ester based
Water (74%), Dimethyl adipate (23%),
Dimethyl glutarate (3%)
Commercial Paint Strippers
Formulation Commercial Paint Stripping Formulations
IKlean Strip KS-3 Premium StripperZip-Strip Paint & Varnish Remover
IISavogran Strypeeze OriginalNational Solvent Liquid Stripper
IIIKlean Strip Liquid RemoverParks Furnitute Remover
IVSavogran Biodegradable StrypeezeSpecialty Env. Tech. Citristrip
VNational Solvent Liquid Ultra Safe StripperKlean Strip Wood Finishers Pride Varnish Stripper
VIPyrox Safe StripperParks Pro Stripper II
VII 3M Safest Stripper
Glove Selection Criteria
• Variety of different glove polymers– Butyl rubber – Nitrile rubber– Natural rubber – PVC – Neoprene – Polymer combinations
• Permeation resistance against paint stripping formulation chemicals
• Unsupported gloves only• Some gloves available to consumers
Glove Selection
North Butyl Rubber Style B-161 Guardian Butyl-Standard
Comasec Butyl Plus(Butyl/Neoprene overdip)
Ansell-Edmont Snorkel PVC Style4-414
Boss PVC Style 1FP2714 Pioneer Disposable Vinyl
Ansell-Edmont Neoprene Style 29-845
Pioneer Neoprene Style N-44 Pioneer Technic Neoprene Style
NS401
Ansell-Edmont Nat.Rub. Style 392 Best Natural Rubber Value Master Thompson & Formby Refinishing
Gloves
Ansell-Edmont Nitrile Style 37-165 Wells Lamont Nitrile Style 178 Best Nitrile Nitrosolve Best N-Dex Style 9005 (thin nitrile)
Pioneer Strip&Stain Style E194(Nat/Neo/Nit )
Best Chem Master (Neop./Nat.Rub.)
Comasec Multiplus (PVC/Nitrile)
Degradation Testing
• Industry practice (no standard available)– One sided contact– 4-hour exposure– Measurement of weight/thickness changes– Visual observation ratings (swelling, discoloration,
curling, delamination, and deterioration)• “0” - no effect• “1” - mild or moderate effect• “2” - severe effect
Permeation Testing
• Standard Test Method– ASTM F 739 (continuous contact)– ASTM F 1383 (intermittent contact)
• Test Parameters– 4-hour duration– room temperature (25 + 2oC)– splash collection method– GC/FID for formulations I - III– GC/MS for formulations IV - VII
Permeation Testing
• Intermittent contact approach– 5 minutes chemical exposure– 10 minutes purge
• Test measurements– Breakthrough time (normalized)– Permeation rate– Determined for each mixture
component TimeP
erm
eatio
n R
ate
Overall Results
• 7 glove styles show best degradation resistance
• Continuous permeation testing shows longer BTs for plastic laminate and butyl gloves
• No improvement for intermittent permeation testing
• Permeation of gloves by commercial strippers consistent with surrogate strippers
Degradation screening
Continuous permeation testing
Intermittent permeation testing
Testing against commercial paint strippers
Degradation Criteria
• Acceptance criteria– Weight change
< 25%– Thickness change
< 25%– Overall rating < 3– No penetration of
test specimens
Degradation Weight Change
Degradation Test Results
• Gloves failing against one formulation– Glove E (4H glove); Glove J (North Butyl B-161),
Glove P (Comasec Butyl Plus)
• Gloves failing against two formulations– Glove S (Guardian Butyl-standard)
• Gloves failing against four formulations– Glove G (Pioneer Strip&Stain), Glove H (Pioneer
Neoprene NS 401), Glove K (Thompson & Formby Refinishing gloves)
Permeation Test Results
Lowest Breakthrough Time (minutes)
E - Safety 4; P - Comasec Butyl Plus; S - Guardian Butyl
K - North Butyl B-161, K - Thompson & Formby Refinishing
Comparison of Permeation
Actual Paint Stripper Results
Lowest Breakthrough Times (minutes)
Conclusions
• Multi-stage testing program useful for determining permeation resistance
• Glove permeation resistance did not always improve with decreasing exposure
• Surrogate paint strippers do not always emulate actual stripper permeation
• Paint strippers with volatile solvent permeate quicker than those containing NMP or dibasic esters
Acknowledgement
This work was supported by a grant from the N-Methylpyrrolidone Producers Group, Inc., Washington, D.C.
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