a comparative analysis of glove permeation resistance to paint stripping formulations jeffrey o....

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.