Document 6wjV0RRrLe39Y0azJ7R2G2y03

IXmiilo.HL.it by |l > IIP A Uhi.uy j .11 tu 54 Is Xmiii-o 2! AIHA Journal 63:62-71 (2002) Ms, #305 A uthors Jeffrey O. Stull' R ic h a rd W. T h o m a s 1' Lawrence E. Jam es' 'IntcraaLioiial Personae! Protection Inc,, 10907 Wareham C ourt, Austin, TX 78739; 'T R I/E nvironrnenlal Inc., 9063 Bee Caves Road, Austin. Texas 78733; 'Research Services U nit, BASF Corporation, Wvandotte, M l 48192 A Comparative Analysis of Glove Permeation Resistance to Paint Stripping Formulations Although there is a wide variety of work gloves available to users of commercial paint stripping products, there are no published studies examining which type of gloves provide the best protection. To address this need, a multiphase study was undertaken to evaluate how several types of gloves resist multichemical-based paint stripping formulations. Due to the wide range of commercial paint stripping formulations available, seven categories of surrogate paint stripper formulations were created to evaluate glove performance initially. Twenty different glove types were identified for initial evaluation. Degradation resistance screening was carried out for each glove style and paint stripping formulation. Screening results were used to identify those glove styles least affected by the surrogate paint strippers. Those gloves were then evaluated for their resistance to permeation using continuous contact testing based on ASTM Test Method F 739. Glove styles showing extensive permeation with early breakthrough were then evaluated to see how they performed with only intermittent contact with the surrogate paint strippers using a modified form of ASTM Test Method F 1383. These results were used to select glove styles to be tested using commercially available paint stripping products. Gloves made of plastic laminate and butyl rubber were the most effective against the majority of paint strippers. More glove styles resisted permeation by N-methylpyrrolidone and dibasic ester-based paint strippers than conventional solvent products such as methylene chloride, methanol, isopropanol, acetone, and toluene. The study also found that decreased contact time caused relatively little change in permeation resistance and that the surrogate paint stripper data did not always accurately predict resistance to the commercial paint stripper formulations. Keywords: chemical degradation resistance, chemical permeation resistance, glove testing, N-methylpyrrolidone (NMP), paint strippers, protective gloves this 'iurk was supported bv a grani fono the NXkimiptn-olkfone Producers Ciroup Inc., Washington, D.C. Consumers and industry alike commonly use paint strippers, varnish removers, and similar compounds to remove paint and other finishes from wood and other sur faces. Traditional paint strippers contain a variety of different volatile chemical compounds, includ ing methylene chloride, methanol, isopropanol, acetone, and toluene. More recently, less volatile chemicals, such as N-methylpyrrolidone, d-limonene, y-butyrolactone, and dibasic esters have been used in new paint stripper formulations. Paint stripping often involves intimate and prolonged contact between the user's hands and the chemicals used. Although some paint stripper manufacturers provide gloves with their prod ucts, relatively7 little information is available to guide the end user in selecting gloves that pro vide the best protection for specific strippers. Se lecting gloves based on individual components in specific paint stripper formulations may7not ac count' for synergistic permeation behavior ob served. for many different chemical mixtures.''" To determine which types o f gloves afford the greatest protection against contact with paint strippers, an extensive program was designed to evaluate the resistance of gloves to permeation by paint stripper mixtures. 62 AIHA Journal (63) JanuaryyTe binary 2002 Copyright 2002, American Industrial Hygiene Association Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00001 Downloaded by [US EPA Library] at 06:54 18 August 2017 GENERAL APPROACH The glove testing program was designed to evaluate several gloves styles for resistance to paint strippers to identify the best gloves for wearer protection against specific paint stripper for mulations. This work, as originally defined, was divided into four major phases. Phase I identified suitable candidate gloves and performed deg radation resistance screening of 20 commercially available gloves by seven laboratory surrogates of paint strippers sold in local hard ware or home center stores. Seven of the 20 gloves tested did not exhibit severe degradation. In Phase II the seven gloves that did not exhibit severe degra dation were subjected to continuous contact permeation testing against the seven surrogate paint strippers. For gloves that showed permeation of the surrogate mixtures, breakthrough times and permeation rates were determ ined for individual chemical compounds. In Phase III those glove styles that exhibited rapid permeation of the surrogate paint stripper formulations in Phase II were tested using intermittent contact permeation testing. Phase IV consisted of permeation testing of the three "most successful" glove types with actual commercial paint strippers cor responding to the seven surrogate paint stripping formulations. METHODS Selection of Test Chemicals Surrogate Paint Stripper Formulations For the purpose of minimizing testing for representing a wide range of commercial paint strippers, surrogate paint stripper for mulations were devised to represent the range in commercial paint stripper composition. These surrogate paint stripper formulations were based on a review' of the marketplace using paint stripper composition information provided by the Consumer Product Safe ty Commission and the U.S. Environmental Protection Agency (EPA) together with input from a chemical manufacturer trade group. Seven different surrogate paint stripper formulations were then created using various combinations of methylene chloride; methanol; isopropanol; acetone; toluene; N-methylpyrrolidone; dliraonene; y-butyrolactone; Exxate 600 solvent (oxo-hexyl ace tate); Ektapro EEP (ethyl 3-ethoxy propionate); dimethyl adipate; dimethyl glutarate; dipropylene glycol methyl ester; and water. These surrogate paint stripper formulations, listed in Table I, were intended to represent both conventional solvent-based paint strip pers as well as N-methylpyrrolidone or dibasic ester-based paint strippers. Specific Commercial P aint Strippers The original information from the Consumer Product Safety Commission and EPA was used to select two commercial paint strippers in each of the seven categories represented by the sur rogate paint stripper formulations. This was accomplished for all but formulation Category VII, for which only' one commercial paint stripper could be identified. The resulting list of paint strip pers and their reported composition appear in Table II. The re ported composition was taken from either information provided hyTthe manufacturer or from a study performed by EPA. A quantitative analysis of the composition of each commercial paint stripper was performed to determine which permeants TABLE I, Paint Stripping Surrogate Formulations (I) Methylene chloride based Methylene chloride (80%), acetone (10%), toluene (4%), methanol (3%), Isopropanol (3%) (IIj Methylene chloride/acetoneitoluene/methanol based Methylene chloride (30%), toluene (26%), acetone (22%), methanol (22%) (III) Acetone/methanolitoluene based Acetone (46%), toluene (35%), methanol (19%) (IV) N-methylpyrrolidone based N-methylpyrrolidone (75%), d-llmonene (25%) (V) N-methylpyrrolidone (^50%) N-methylpyrrolidone (50%), y-butyrolactone (28%), Exxate 600 solvent (17%), Ektapro EEP (5%) (VI) Dibasic ester/NMP based Dibasic ester blend (55%),A N-methylpyrrolidone (36%), dipropylene glycol methyl ester (9%) (VII) Dibasic ester based Water (74%), dimethyl adipate (23%), dimethyl glutarate (3%) Mote: Composition reported as weight percentage. ?The dibasic ester blend is Formulation VII. should be quantified in the permeation testing. In some cases these analyses provided results chat, did not match the reported composition of the product. Glove Selection Selection o f Gloves for Degradation Screening A multistage process was used initially' to select a relatively' large number of gloves for chemical degradation resistance screening and to use the data from each phase to select the " most, success ful" gloves for each successive phase. Initial selection of candidate gloves was based on a number of factors. Review's of chemical resistance databases and manufactur ers' data identified glove materials that appeared to offer " ade quate" resistance to the various chemicals used in the seven dif ferent surrogate paint stripping formulations.*2 41 The inclusion of several different types of glove materials and the ready availability of the gloves to consumers were also factors. All of the existing chemical resistance data for gloves 'were for neat chemicals only; there were no data on mixtures that approx imated any of the seven surrogate paint stripping formulations. In addition, there were no data at all for some of the chemicals listed in these formulations. The final list of 20 glove styles, appearing in Table III, was created by selecting two to three glove types from selected generic classes of gloves found to offer some degree of chemical perme ation resistance as determined by' an examination of the two da tabases, discussions with glove manufacturers, and preliminary glove survey' information provided by paint stripper manufactur ers. Some consideration was given to glove expense; Viton and other fluoropofymer gloves were not considered due to their pro hibitive cost. Other materials were eliminated from consideration based on known performance problems. Polyvinyl alcohol gloves, for example, cannot be used around water even though they' have outstanding chemical resistance against several solvents. Selection o f Gloves for Continuous and Interm ittent Contact Permeation Testing Seven different gloves w'ere selected for continuous contact per meation testing against each surrogate paint stripper formulation. Six of these gloves were selected based on their ranking in Phase I degradation resistance screening tests. These included the same AIHA Journal (63) January/February 2002 63 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00002 TABLE II. Selected Commercial Paint Strippers and Identified Compositions Formulation Paint Stripper Identified Composition' IA IB A MB IMA ms IVA IVB VA VB VIA VIB VI IA Klean Strip KS-3 Premium Stripper Zip-Strip Paint & Varnish Remover Savogran Strypeeze Original National Solvent Liquid Stripper Klean Strip Liquid Remover Parks Furniture Remover Savogran Biodegradable Strypeeze Specialty Env. Tech. Citristrip National Solvent Liquid Ultra Safe Stripper Klean Strip Wood Finishers Pride Varnish Stripper Pyrox Safe Stripper Parks Pro Stripper II 3M Safest Stripper 76% methylene chloride, 5% isopropanol, 3% methanol, 3% butyl cellosolve 75% methylene chloride, 8% ethanol, 3% methanol, <1% decane 35% toluene, 22% methanol, 20% acetone, 14% methylene chloride 87% methylene chloride, 5% methanol <1% acetone, <1% toluene 46% acetone, 42% ethyl acetate, <1% iso-octane 34% acetone, 25% isopropanol, 21% methanol, 17% toluene, <1% methylene chloride 67% NMP, 5% d-limonene, 25% dimethyl adipate, 3% dimethyl glutarate 37% NMP, 23% d-iimonene 22% NMP, 17% ethylene glycol, 61% Exxate 20% NMP, 37% y-butyrolactone, 20% ethyl-3ethyoxyproplonate 15% NMP, 5% dimethyl adipate, 1% dimethyl glutarate, 50% propylene carbonate 40% NMP, 5% dimethyl adipate, 11% dimethyl glutarate, 44% ethyl-3-ethyoxypropionate 18.7% dimethyl adipate, 1.8% dimethyl glutarate balance primarily water 'Composition reported as weight percentage. four gloves for each surrogate paint stripper formulation, the plas tic laminate glove (Style E), and the three butyl rubber glove styles (Styles f, P, and S) (see Table III). The remaining two gloves selected varied depending on the formulation. The seventh glove selected was the next best performing commercially available glovestyle (distributed through the hardware retail business). Intermit tent contact permeation testing was conducted on those, gloves that showed normalized permeation breakthrough times of less than 2 hr for one or more formulation components. Gloves se lected for continuous and intermittent contact permeation testing arc shown in Table IV. Selection o f Gloves for Permeation Testing Against Commercial Paint Strippers Three different gloves were chosen for evaluation against each of the. selected commercial paint strippers. Glove Style E consistently outperformed, all ocher gloves in terms of degradation and per meation resistance. The next "best" performing group of gloves (Styles J, P, and S) were those containing butyl rubber. O f these, Glove Style J demonstrated longer breakthrough times and lower permeation rates overall. Therefore, Glove Styles E and } were chosen as the first two gloves to be tested against the commercial paint stripper in each formulation category. The third glove style was selected based on continuous contact permeation data show ing the longest nonbutyl rubber glove permeation breakthrough time. This selection process permitted the inclusion of three rel atively different glove styles: Glove Style E is a highly chemical resistant, inexpensive glove; it is not, however, a traditional glove design and does not fit as well as rubber gloves. Butyl rubber gloves, although comfortable to wear, are rela tively expensive. The third glove style was a less expensive rubber glove. For all surrogate, formulations, except for Surrogate Formulation VII, the. third glove style chosen was Style K. For Surrogate Formulation VII, Style F was selected. Glove Chemical Degradation Screening General Approach In the chemical degradation resistance screening, one side, of the. test material was exposed to the chemical for 4 hr and changes in weight, thickness, and appearance were recorded. A one-sided ex posure was considered important because many candidate gloves were, not homogeneous or had specific linings that absorb chem icals differently than the normal exposure surface. The 4-hr ex posure period is commonly used by the. glove industry for rating glove degradation resistance and provides adequate time for mea suring changes in glove condition. Weight change and changes in thickness are generally coupled with visual observations as consis tent and useful measures of glove performance against chemicals for degradation testing. Specimen Preparation Fisher Septa~Jar (Chicago, 111.) wide-mouth containers (60 mL) with Teflon fluorocarbon resin/silicone septa were, used as the. exposure container. The septa were removed from each bottle be cause the glove specimen would act as the gasket material between the bottle and the. lid. The lid of the jar contained an 18 mm diameter hole, which allowed any evidence of severe degradation in the form of dripping or seepage to be observed. Glove material disks of 50 mm diameter were, taken from foe glove palms, backs, and sides for evaluation. Removal of specimens from nonhomogeneous areas of foe glove was avoided. A total of three specimens was used for each glove type/paint stripping formulation combi nation. The weight and. thickness of each specimen was deter mined and recorded prior to evaluation. An Ohaus model CT200-S (Pinebrook, N.J.) balance was used to weigh each specimen 64 AIHA Journal (63) January/February 2002 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00003 TABLE III. Glove Candidates for Degradation Resistance Testing Style A B C D E F G H I J K L M N 0 P Q R S V 'Consumer product. Manufacturer Ansel! Edmont (Conshocton, Ohio) Ansei! Edmont Ansell Edmont Ansell Edmont Safety 4 (Lenexa, Kan.) Pioneer (Willard, Ohio) Pioneer Pioneer Pioneer North (Charleston, S.C.) Thompson & Formby (Cleveland, Ohio) Wells Lament (Niles, III.) Best Manufacturing (Menlo, Ga.) Best Manufacturing Comasec (Enfield, Conn.) Comasec Best Manufacturing Best Manufacturing Guardian (Willard, Ohio) Boss (Kewanec, 111.) Glove Identification natural rubber style 392 neoprene style 29-845 nitrile style 37-165 Snorkel PVC style 4-414 4H plastic laminate neoprene style N-44A Strip&Staln style E194 (nat/neo/nit)A Technic neoprene style NS401A disposable vinylA butyl rubber style B-161 refinishing gloves* nitrile style 178A Chem Master (neoprene/nat. rub.) N-Dex style 9005 (thin nitriie) Multiplus (PVC/NBR nitrile) Butyl Plus (butyi/neoprene overdip) Nitrile Nitrosoive Natural Rubber Value Master Butyl-Standard PVC style 1FP2714* Thickness (mil) 22 17 22 65 2.7 22 19 22 5 16 30 15 26 6 65 25 15 18 15 54 Downloaded by [US EPA Library] at 06:54 18 August 2017 to the nearest 0.01 g, whereas an Ames Series 27-2 (Waltham, Mass.) thickness gauge was used to measure specimen thickness to the nearest millimeter. Exposure Period Investigators placed 20 mL of a formulation in an exposure jar. A glove specimen was then inserted into the lid of the jar, and the jar lid was firmly secured to the jar. The exposure period was be gun by inverting the jar and bringing the liquid into contact with the glove material. The inverted jars were placed on a ventilated rack 25 mm above a piece of blotting paper. At the end of the 4hr period, the blotter paper and jar lid were examined for evidence of chemical dripping or seepage. Measurement o f Weight and Thickness Change Specimens were carefully removed from the jar lid and placed be tween two sheets o f blotting paper (Georgia Pacific style HM 9201, two-ply towels). A weight was then placed on top of the blotting paper to achieve a 3.4 kPa pressure on the specimen for a period of 10 sec. The specimen wras then turned over and reblotted for another 10 sec using die same procedure. Immedi ately following the blotting procedure, the weight of the exposed specimen was measured and recorded to the nearest 0.01 g fol lowed by measuring the specimen's thickness to the nearest mil limeter. To prevent variation in experimental technique, the same test operator performed all determinations. Visual Evaluation o f Specimen Condition Ratings o f the specimen's condition were made in the following categories: swelling, discoloration, curling, delamination, and deterioration. Three choices were provided to rate these material conditions: 0--no effect; 1--mild or moderate effect; and 2--severe effect. In addition to visual ratings, photographs were taken for comparing a "pristine" specimen to representative specimens exposed to each of the seven different formulations. Continuous Contact Permeation Testing Glove Specimen Preparation Die cut samples (25 mm diameter) were taken from the glove palms, backs, and sides for evaluation. Removal of specimens from nonhomogeneous areas o f the glove was avoided. Three specimens TABLE IV. Selected Glove Styles for Permeation Testing Surrogate Paint Selected Glove Styles* Stripper Formulation 1 2 3 4 s 6 1 I E P S J K N V II E P S J K V H III E P s J K I R IV E P s J K A G V E P s J K H M VI E P s J K M H VII E P s J K F AG!ove styles correspond to gloves listed in Table Ml; glove styles In boldface type indicate glove styles that were also evaluated for intermittent contact permeation resistance testing. Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ASHA Journal (63) January/Febmaty 2002 65 ED 002061 00050587-00004 IXmiilo.HL.it h\ |l > IIP A Uhi.uy j .11 tu 54 Is Xuu'i^! were used for each glove type/paint stripping formulation com bination. The weight and thickness of each specimen was deter mined and recorded, prior to evaluation. An Ohaus model CT200-S balance was used to weigh each specimen to the nearest 0.01 g for computing specimen unit area weight, whereas an Ames series 27-2 thickness gauge was used to measure specimen thick ness to the nearest 0.001 inch or mil. Specimens were edge-sealed between two Teflon gaskets with the glove material acting as a barrier between the challenge and collection sides of the perme ation cell. Permeation Test M ethod Permeation testing was performed in accordance with a modified version o f ASTM F 739-95, Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases, The modification of the test method was to use a smaller diameter test cell. Use of the smaller test cell has been shown to be equiv alent through previous studies and reduces the volume of test chemical consumed in testing.15'6*Although the standard specifies procedures for conducting the test, a number of test parameters arc left to tire discretion of the test laboratory. These primarily include the configuration of the permeation system and detector. The selection of the detector affects how the system is set up and the operating conditions for the test. It also greatly affects the reported permeation breakthrough time, because insensitive de tectors will yield longer breakthrough times. Permeant Collection Technique A splash-type collection was used for this testing. This approach was adopted primarily because Formulations IV through VII con tained relatively nonvolatile components, which could not be eas ily captured using conventional permeation collection techniques. Splash-type collection has previously been demonstrated as an ef fective means for collecting permeant of relatively nonvolatile chemicals.<7_9) This method employed 2-ethoxyethanol or metha nol as the collection solvent. The choice of solvent was based on ensuring broad solubility of formulation components while mini mizing leaching of glove material additives. The solvent rinse con sisted. of applying 2.0 ml. of 2-ethoxyethanol (or methanol) for a residence time o f 2-3 sec on the collection surface o f the test specimen. Solvent rinses were individually applied and collected at 15-min intervals over die 4-hr test period. Detection Methods for Conventional Solvent-Based Formulations Gas chromatography was used for separating and quantifying for mulation components for Formulations I through III, which con tained primarily volatile solvents. Gas chromatography was per formed with an HP 5890 (I'alo Alto, Calif.) gas chromatograph (GC) equipped with a flame ionization detector and 30 m HP-1 column. A temperature program of 40C for 6 min with a 20 C / min ramp to 100C with no hold time was used. This procedure yielded a 2.5 p g /m L detection limit for all compounds. Detection Methods for N-Methylpyrrolidone (NMP)-Based Formulations Because of the relatively nonvolatile components of Formulations IV through VII, a more sophisticated analytical technique was re quired: use of a GC combined with a mass spectral detector (Per kin Elmer Automated System GC with auto injector). The specific procedure used was injection of 1 xL into a Perkin Elmer (Nor walk, Conn.) Autosystem GC with auto injector equipped, with a 60-rn ] and W Scientific (Palo Alto, Calif.) DB-VRX column and Perkin Elmer Q-Mass 910 quadrapole rod detector. An injector temperature of 250"C was used with an initial oven temperature of 100C for 5 min and ramp temperature of 10C/min to 24QC, Helium was used at a flow rate of 1.12 m l,/m in with no split. Mass spectral identification and quantification was performed using selected ion masses for each respective formulation com ponent. External standardization was used in calculating the ana lytical results. Established detection limits were calculated to be 0.1 n g /p L . The detection Limits were determined by using the lowest response factor and multiplying that factor by a verified response of 1000 area counts. Quality assurance and quality con trol were accomplished by running a standard with every batch run (20 samples) to verify the five-point cali bration curve. All tests were run in triplicate for a period of 4 hr at room temperature (25 -r 2C). Temperature control was managed by placing the test ceils in a permeation testing box that had a ther mostat and series of lamps and a fan to control temperature with in the chamber. In addition to three replicates, a blank consisting o f test glove material without challenge chemicals was run. Mea surements o f the blank were used to establish baseline measurements. The measured concentration of each component wets deter mined for each solvent-rinse and reported at the end time of the interval evaluated. For example, when a solvent rinse collection was performed at the end of 30 min, the resulting concentrations of formulation components were reported for 30 min but actually included all permeant that passed through the material from 15 to 30 min. In determining actual breakthrough time, the time preceding the reported time when chemical was first detected be came the actual breakthrough time for the specific component using the limit of detection for the particular analytical approach. Normalized breakthrough time was based on the time preceding the reported time where a permeation rate equal to or greater than 0.1 p,g/cm2min was determined. Intermittent Contact Permeation Testing The same specimen preparation, collection technique, and. detec tion strategies were used for intermittent contact permeation test ing as for continuous contact permeation tests. Differences in per meation testing for intermittent contact tests were based, on the selected test method. Permeation testing wets instead performed, in accordance with a modified version o f ASTM F 1383-92, Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases Under Conditions of Intermittent Contact using Condition B. Condition B involves cycling the formulation's ex posure to tire glove specimen oxer die duration of the test (4 hr) using the following technique: 5 min of chemical (formulation) exposure; and removal of the chemical (formulation) from the test cell (by pouring it out) and purging of the test cell with ``dry" air for 10 min. Normalized breakthrough time was based on the time preced ing die reported time where a cumulative permeation equal to or greater than 0,05 jxg/cm3 wras determined. RESULTS AND DISCUSSION Degradation Resistance Screening Testing Results for degradation resistance screening testing are summa rized in Table V, which compares percentage changes in weight 66 AIHA Journal (63) January/February 2002 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00005 TABLE V. Summary of Degradation Resistance Testing Results Percentage Weight Change by Surrogate Paint Stripper Formulation Style* I II 111 IV V A 96.2 B 105.8 C 120.5 D 49.0 E 0.0 F 57.7 G 72.2 H 64.9 I 47.1 J 30.2 K 70.1 L 295.2 M 51.4 N 12.7 0 52.4 P 32.0 Q 110.4 R 98.1 S 26.2 V 29.8 39.1 50.9 139.0 45.9 2.4 34.0 34.5 33.9 -5.0 13.9 36.4 137.2 49.9 138.4 33.9 16.2 97.3 43.0 14.7 10.0 32.7 44.1 101.4 45.0 2.4 36.8 35.4 37.2 23.1 8.7 27.9 142.5 33.0 152.7 38.2 8.6 113.4 27.7 8.3 34.7 58.6 210.0 258.0 80.2 0.0 105.0 70.0 83.0 -100.0s 23.4 49.9 229.8 65.3 456.6 63.4 17.2 308.8 84.4 31.6 97.5 22.5 109.7 188.7 78.4 0.0 37.3 22.7 14.4 -100.0B 0.8 11.7 296.8 20.6 434.8 72.5 1.6 205.7 22.9 2.3 83.5 "See Tabie Hi for definitions of glove styles. BGlove dissolved completely during chemical exposure. VI 9.5 58.7 122.4 80.1 0.0 26.6 12.0 10.3 - - 100.0s 0.7 6.7 153.0 8.4 268.2 52.2 0.6 159.8 11.4 1.1 76.0 Vil 6.4 23.2 46.4 14.3 0.0 5.9 7.2 7.9 48.2 0.8 5.2 82.6 7.5 86.0 22.5 0.0 51.6 10.2 0.7 37.1 Downloaded by [US EPA Library] at 06:54 18 August 2017 and thickness, overall degradation rating, and pass/fail perfor mance relative to proposed acceptance criteria. Gray boxes indicate results falling outside those criteria. Study acceptance criteria con sisted of die following: Percentage weight change 25% Percentage thickness change <25% Overall rating 3 No dripping (as die result of degradation) These degradation test results showed that no glove met all the performance criteria for every surrogate paint stripping for mulation. The "`better" performing gloves included gloves fail ing against one formulation--Glove Style E (Safety 4 4H plastic laminate glove), Glove Style ] (North Butyl Rubber style B-161), and Glove Style P (Comasec Butyl Plus); gloves failing against two formulations--Glove Style S (Guardian Butyl-Standard); and gloves failing against four formulations--Glove Style G (Pi oneer Strip&Stain), Glove Style H (Pioneer Technic neoprene style NS 401), and Glove Style K (Thompson & Formby Refin ishing Gloves). The majority o f failures were due to weight gains in excess of 25%. O f the seven formulations, Formulations 1 (methylene chlo ride, methanol, isopropanol, and toluene) and IV (>50% NMPbased) were found to be the most " aggressive." The greatest weight gains were generally observed for formulations containing NMP. This is likely due to the lower volatility of NMP and dibasic esters as compared with organic solvents used in other formula tions, such as methylene chloride, acetone, toluene, methanol, and isopropanol, which have higher vapor pressures. Fewer failures were observed on the basis of thickness; however, large weight gains were usually accompanied by swelling and significant chang es in thickness. Visible changes were also useful in rating the gloves' resistance. Swelling and curling were most often reported, whereas many gloves showed various stages of deterioration. Few gloves exhib ited dlamination owing to their homogeneous composition. Overall ratings were used to assess material performance. In nearly all cases high cumulative ratings (those greater than 3) indicating poor resistance were observed when significant weight and thick ness changes were measured. Evidence of dripping was coupled with visual ratings to deter mine glove material performance. Several gloves deteriorated to the point at which liquid penetrated. Other glove styles degraded to an extent chat caused failure of the seal in the exposure jar, resulting in chemical seepage. Although only a few gloves of the same representative glove material were evaluated in this study, it was apparent that certain glove types were wholly unsuitable against these formulations. Both nitrile and PVC gloves exhibited severe degradation to more mixtures. Differences were noted in the performance of the three neoprene gloves, which illustrates how performance of nominally the same generic glove material is affected by glove compound formulation differences. Continuous Contact Permeation Testing Table VI summarizes continuous contact permeation resistance testing as determined by a combination o f actual breakthrough time, normalized breakthrough time, and permeation race for each surrogate formulation. Tests in which no breakthrough was detected are indicated by a normalized breakthrough time of >240 min and a permeation rate of <0.1 p g /c m 2/m in . Only three replicates were performed, so no attempt was made to av erage results. The shortest breakthrough time and highest per meation rate are used to represent a particular glove-formulation permeation test. The test results showed a number of formulation (mixture) components that permeated many of the selected glove styles. In general, glove permeation resistance closely followed the findings from Phase I: gloves that demonstrated the best degradation re sistance also showed longer breakthrough times and lower per meation rates. Only one glove style (Style E, 4H plastic laminate) AIHA Journal (63) January/February 2002 67 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00006 TABLE VI. Summary of Permeation Resistance Data for Continuous Contact Tests Against Surrogate Paint Stripper Formulations* Permeation Resistance Test Data by Glove Style'8 _ Fo iaiion rm Glove E Glove P Glove S Glove J Glove K u - ____________________________________________________________________________________________ Chemical NBT PR MET PR NBT PR NBT PR NBT PR I methylene chloride >240 <0.1 30 85 30 35 60 61 15 60 methanol >240 <0.1 30 3.0 45 1.2 60 1.4 15 3.9 isopropanol >240 <0.1 60 0.7 60 1.4 120 0.9 30 10 acetone >240 <0.1 30 9.2 45 2.4 60 4.6 15 19 toluene >240 <0.1 30 6.8 45 2.9 60 4.3 15 12 II methylene chloride >240 <0.1 150 26 120 50 150 11 <15 27 methanol >240 <0.1 150 34 60 22 150 14 15 63 acetone >240 <0.1 150 7.2 120 3.9 180 2.5 <15 16 toluene >240 <0.1 150 5.4 90 3.8 150 1.8 15 17 m acetone >240 <0.1 180 7.9 150 13 >240 <0.1 15 190 toluene >240 <0.1 180 61 180 7.9 >240 <0.1 15 110 methanol >240 <0.1 180 0.8 180 1.2 >240 <0.1 15 23 V NMPC >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 60 94 d-limonene >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 90 275 V NMP >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 90 7.7 -y-butyrolactone >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 90 1.4 Exxate 600 solvent >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 120 1.5 Ektapro EEP >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 90 1.4 VI dibasic ester biendD >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 NMP >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 180 0.19 DPGMEE >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 90 10 VII water >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 dimethyl adipate >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 210 0.1 dimethyl glutarate >240 <0.1 >240 <0.1 >240 <0.1 >240 <0.1 210 1.3 Note: Permeation resistance test data are provided for the same five giove styies evaluated against each of the seven surrogate paint stripper formulations. 'Permeation resistance test data include normalized breakthrough time (NET) reported in minutes and permeation rate (PR) reported in micrograms per square centimeter per minute. The normalized breakthrough time Is defined as the time at which the permeation rate equals 0.1 p.g/cm2/min. The reported permeation rate is the maximum permeation rate observed over the duration of the test (4 hr). 3The reported normalized breakthrough time is the shortest of the three measured breakthrough times. The reported permeation rate is the largest of the three measured permeation rates. CNMP = N-methylpyrro!idone. The dibasic ester blend is Formulation Vli, EDPGME = dipropylene glycol methyl ester. showed resistance to permeation by all chemicals with the excep tion of two replicates showing 150-min actual breakthrough times against, methanol for Formulation I. The three butyl gloves (Styles P, S, and J) demonstrated the next best permeation resistance. In neatly all cases, permeation resistance of the other glove styles was relatively poor for all formulations, with the exception, of For mulation VII. Gloves generally performed better against Formulations IV to VTI as compared with Formulations I to III, which contained, principally volatile compounds. Selected glove candidates per formed best against Formulation VII, the water-based surrogate paint stripping formulation. For the majority o f tests, results were consistent in terms of both breakthrough times and permeation rates for the three rep licates tested. However, there were some combinations where wide ranges of permeation behavior were observed; it is believed that these variances are due to differences in glove thickness and composition. Intermittent Contact Permeation Resistance Data All of the selected glove-surrogate formulation combinations that had demonstrated rapid breakthrough under continuous contact test conditions also showed intermittent permeation breakthrough times of less than 2 hr for all components. Table VII provides a comparison of normalized breakthrough times for both continuous contact and. intermittent contact per meation resistance tests for selected glove styies and surrogate for mulation chemicals. In many cases there were no changes in nor malized breakthrough time for continuous contact and intermittent contact tests; however, a number of test results showed both shorter and longer normalized breakthrough times. Many of the longer intermittent testing breakthrough times were measured for the surrogate formulations containing volatile chem icals, whereas many of the shorter breakthrough, times were mea sured for NMP and other less volatile chemicals. Permeation rates were measured, at the time of breakthrough for intermittent contact tests, so these rates were generally high compared with continuous contact data. However, the data pre sented in continuous contact tests were based on the steady state or ending permeation rates recorded at the end of the 4-hr tests. When continuous and intermittent contact data are presented on the same basis, performance was equivalent, as shown in the ex amples in Table VIII. These examples demonstrate how much permeation rates can vary. The reasons for these variations are based on the overall permeation behavior for all glove styles with the exception of Glove Style E (Safety 4 4.H. plastic laminate glove). This per meation behavior is classified as Type D, as defined in ASTM F 739 (permeation that goes through a maximum and then levels off at some steady-state rate). Type D permeation behavior is 68 AIHA Journal (63) January/February 2002 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00007 Downloaded by [US EPA Library] at 06:54 18 August 2017 TABLE VII, Comparison of Normalized Breakthrough Times for Continuous and Intermittent Contact Permeation Resistance Tests for Selected Glove Style Surrogate Formulation Combinations Normalized Breakthrough Time (min) Chemical Glove Formulation Style Continuous Intermittent Contact Contact Methylene chloride Acetone Toluene NMP I P 30 60 S 30 30 J 60 75 K 15 15 n S 120 75 K <15 15 V <15 15 i P 30 60 S 45 45 J 60 75 K 15 15 n S 60 90 K 15 15 V <15 15 IV K 60 15 A 30 15 V K 90 45 H 45 15 M 30 30 VI H 60 15 M 90 45 attributed to exposures in which there is moderate to heavyswelling o f the material specimen, during which time the per meation rate achieves a maximum level and then stabilizes as the amount of swelling stays constant.'-9' The degradation test data bear out this phenomenon because some swelling was noted with all rubber glove styles. The overall finding for tills phase is that glove performance was no better for intermittent exposure than for continuous exposure; that is, the same relative amount of permeation can be expected to occur with repetitive 5-min exposures every 15 min as with continuous chemical contact. This is likely the result of chemical driving forces chat remain in effect due to wetting of the gloves' outer surfaces by the formulation itself. This phenomenon has been reported by other researchers in this field/10-12) As a conse quence of this testing, no other glove styles were qualified as " ac ceptable" from applying the 2-br breakthrough time to intermit tent contact permeation test" results. Permeation Testing Against Commercial Paint Strippers Tables IX and X provide a comparison o f the normalized break through times and permeation rates by chemical for two of the surrogate formulations and the representative commercial paint strippers. For the most part, permeation test results for evaluation of the three selected gloves against each commercial paint stripper showed performance consistent with continuous contact perme ation testing with surrogate paint stripper formulations. Glove per formance was ranked similarly: Glove Style E (the 4H glove) provided the " best" permeation resistance for commercial paint strippers tested. No permeation was detected for any commercial paint strippers except for those that contained relatively high levels of methylene chloride (For mulation I). Composition analysis of Commercial Paint Stripper II-B shows relatively high levels of methylene chloride. This com mercial paint stripper would have been more appropriately classi fied as a Formulation I paint stripper. The next " best" glove was a butyl rubber glove (Glove Style }). This particular glove did well against most NMP-based paint strippers and paint strippers with relatively' low levels of methylene chloride. The third glove, usually' the Thompson & Formby natural rub ber glove, generally' showed, rapid permeation for solvent-based commercial paint strippers and only' -achieved breakthrough times greater than 2 hrs for the dibasic ester-based paint stripper. All of the volatile solvent-based paint strippers permeated, at or before 15 min. In many cases the permeation rates of the three glove styles differed by an order of magnitude. This was particularly' evident in examining commercial paint strippers corresponding to For mulations I--III. In comparing glove performance against commercial paint strippers with performance against the surrogate formulations, poorer permeation resistance was generally noted for gloves in the commercial paint stripper permeation tests against surrogate For mulations I--III. Permeation resistance testing o f gloves against the commercial NMP-based and dibasic ester formulations showed performance in line with surrogate formulation testing. Differences in results between surrogate formulations and cor responding commercial paint stripper formulations are believed to be caused by deviations in the composition of commercial paint strippers compared with the surrogate formulations or to the syn ergistic effects of additional mixture components not accounted for in the surrogate formulations. TABLE VIII. Comparison of Continuous and Intermittent Contact Permeation Rates for Selected Glove Style Surrogate Formulation Combinations Methylene Chloride Permeation Rate i^g/cm2/rnm} Glove Style Rep. Continuous Continuous Intermittent No, Steady State Maximum Maximum Glove K, Thompson & 1 60 421 400 Formby Refinishing Glove 2 57 381 360 3 34 486 480 Glove V, Boss PVC Style 1 130 671 310 1FP2714 2 190 579 380 3 180 1052 372 Note: Both the steady-state and maximum permeation rate are reported for continuous contact permeation resistance tests, whereas the maximum permeation rate is reported only for intermittent contact permeation resistance tests. Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 A!HA Journal (63) January/Febmaty 2002 69 ED 002061 00050587-00008 TABLE IX. Comparison of Permeation Test Results for Surrogate Formulation I and Representative Commercial Paint Strippers Challenge* Mixture Component Percentage Normalized Breakthrough Time3 (min) Glove E (Plastic) Glove J (Butyl) Glove K (N. Rub.) Glove E (Plastic) Permeation Rate0 (gg/enti/min) Glove J (Butyl) Methylene chloride Formulation I 80 Stripper i-A 76 Stripper i-B 75 M ethanol >240 60 15 <0.1 61 15 <15 <15 3.9 91 15 15 <15 3.4 160 Formulation i 3 Stripper i-A 3 Stripper i-B 3 Isopropanol (IPA) or ethanol 150 60 15 0.06 1.4 30 <15 <15 0.45 2.8 >240 30 15 <0.1 2.6 Formulation i Stripper i-A Stripper i-B 3 (IPA) >240 120 30 <0.1 0.9 5 (IPA) 120 15 <15 0.15 3.3 8 (ethanol) 180 15 <15 0.07 1.8 AThree chemicals from the formulation were seiected for comparison purposes. "Shortest of three normalized breakthrough times recorded. 'Largest of three reported permeation rates. Glove K (N. Rub.) 60 520 380 3.9 25 14 20 35 4.4 IJim iilo.H L.it h\ |l > IIP A Uhi.uv j .11 tu 54 Is Xuu'i^! CONCLUSIONS This testing has demonstrated the usefulness of a multistage ap proach to evaluating glove permeation resistance against paint strippers. The use of surrogate paint stripper formulations repre senting categories of commercially available paint strippers allowed for screening tests chat identify suitable gloves types for a wider range of commercial products. This study further showed the val ue of degradation testing for eliminating unsuitable glove types. However, paint stripper formulations represent varying multichemical mixtures and, ultimately, commercial paint strippers must be individually evaluated for permeation resistance against selected gloves. These results show that the relatively small-molecule, volatile, chemical-based solvents cause somewhat more degradation and considerably more permeation of glove types as compared with NMP and dibasic ester-containing formulations against the same gloves. Most rubber gloves appear to show relatively rapid per meation by volatile solvent mixtures as represented by surrogatepaint stripper formulations. Only a plastic laminate glove, resisted permeation by the majority of surrogate formulations arid com mercial paint strippers. Butyl rubber gloves provide the next best level of permeation resistance, but still showed rapid permeation for some mixture components, notably methylene chloride. On the other hand, formulations containing NMP an d /o r dibasic es ters showed less rapid permeation of butyl gloves and in many cases showed no detectable permeation for the seiected butyl and natural rubber glove styles. An important finding of this study is that glove permeation did not improve with intermittent contact time. As long as the contact is repetitive and sustained over the same period of time as used in continuous contact tests, permeation results will be similar. This type of permeation performance indicates that wetting of cite glove surface by the paint stripper will provide a sufficient driving force to continue permeation, even when the bulk of liquid is removed. Therefore, shortened exposures may nor be an acceptable practice for extending glove service life or for improving the marginal chem ical resistance offered by some glove types. The data provided in this study should be useful for establishing appropriate glow, types for different commercial paint strippers by matching cite composi tion of the nearest surrogate formulation with the composition of TABLE X. Comparison of Permeation Test Results for Surrogate Formulation IV and Representative Commercial Paint Strippers Challenge* Mixture Component Percentage Normalized Breakthrough Time6 (min) Glove E (Plastic) Glove J (Butyl) Glove K (N. Rub.) Glove E (Plastic) Permeation Ratec (gg/cm:/min) Glove J (Butyl) NMP Formulation IV Stripper iV-A Stripper iV-B d -llm o n e n e Formulation IV Stripper iV-A Stripper iV-B 75 >240 >240 60 <0.1 <0.1 67 >240 >240 90 <0.1 <0.1 37 >240 180 60 <0.1 0.3 25 >240 >240 90 <0.1 <0.1 5 >240 >240 90 <0.1 <0.1 23 >240 180 60 <0.1 0.6 "Three chemicals from the formulation were seiected for comparison purposes. "Shortest of three normalized breakthrough times recorded. cLargest of three reported permeation rates. Glove K (N. Rub.) 94 6.6 14 280 3.8 17 70 AJHA Journal (63) January/Fehruaiy 2002 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 ED 002061 00050587-00009 the respective commercia! paint stripper. Nevertheless, because of several potential synergistic effects well established in the literature and in this study for mixture permeation, it is highly recommended that glove selection decisions be based on testing of the commercial paint stripper against die specific glove in question. REFERENCES 1. Mickelsen, ILL*, and R.C. Hall: A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. A m . Ind. Hyg. Assoc. J. 45:941-947 (1987). 2. Forsberg, K,, and L .H . Keith: Chemical Protective Clothing: .Per meation and Degradation Compendium. Eoca Raton, Fla.: Louis Publishers/CRC "Press, 1995, 3. Schwope, A.D, IIP. Costas, J'.O. Jackson, J.O . Stull, and D.J. Weitzman: Guidelinesfor the Selection of Chemical Protective Clothing\ 3rd ed. Cincinnati, Ohio: AGGIH, 1987. 4. M ansdorf, S.Z., and K. Forsberg: Quick Selection Guide to Chemical Protective Clothing, 2nd ed. New York: Van Nostrand, 1993. 5. Henry, N .: Comparative evaluation of a small version o f the ASTM permeation test cell versus the standard cell. In S. Mansdorf, R. Sager, and A. Nielsen, editors, Performance of Protective Clothing: 2nd Sym posium, A STM STP 989 (pp. 236-242). Philadelphia: ASTM, 1988. 6. Berardinelli, S.P., ILL. Mickelsen, an d M .M . 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Nelson, G .O ., B.Y. Lum, G.J. Carlson, C. Wong, and J.S. Jo h n son: Glove permeation by organic solvents. Am. Ind. Hyg. Assoc. J. 42:217-225 (1981). 11. Schwope, A .D ., IL Goydan, T. C arroll, and M , Royer: Test meth ods development for assessing the barrier effectiveness of protective clothing materials. In Proceedings of the Third Scandinavian Sympo sium on- Protective Clothing Against Chemicals and Other Heath Risks (pp. 15-23). Gausdal, Norway: Norwegian Defence Research Estab lishment, .1989. 12. M an, V.L., V. Bastecki, G. Vandal, and .P. Bentz: Permeation of protective clothing materials: Comparison of Liquid contact, liquid splashes, and vapors on breakthrough times. Am. Ind. Hyg. Assoc. J. 48:551-559 (1987). Downloaded by [US EPA Library] at 06:54 18 August 2017 Sierra Club v. EPA 18cv3472 NDCA Tier 3/4 AIHA Journal (63) January/Febmaty 2002 71 ED 002061 00050587-00010