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AATCC TM112 2020 1 1 Purpose and Scope 1 1 This test method is applicable to textile fabrics that may release formalde hyde particularly fabrics finished with chemicals containing formaldehyde It provides accelerated storage conditions and an analytical means for determining the amount of formaldehyde released un der the conditions of accelerated storage see Section 5 and 10 1 This test method determines free and hydrolyzed formal dehyde and any additional formaldehyde which may be generated under acceler ated storage conditions 1 2 An optional accelerated incubation procedure is available see 13 6 1 3 An optional submersion method which approximates the amount of hy drolyzed formaldehyde while closely simulating normal user conditions is AATCC TM 206 2 Principle 2 1 A weighed fabric specimen is sus pended over water in a sealed jar The jar is placed in an oven at a controlled tem perature for a specified length of time see 13 5 The amount of formaldehyde absorbed by the water is then determined colorimetrically 3 Terminology 3 1 formaldehyde release n That formaldehyde exuded from textiles under the accelerated storage conditions of this test including that which is free un bound or occluded from unreacted chemicals or from finish degradation as a result of this test 3 2 free formaldehyde n Formal dehyde that is not bonded to a finish or a fabric is considered to be free formalde hyde In this form formaldehyde can be readily extracted from the fabric by im mersion in water 3 3 hydrolyzed formaldehyde n Although originally part of a larger chemical structure such as a crosslinking reactant during the course of this test the formaldehyde is cleaved from the larger molecule and dissolved into water 4 Safety Precautions NOTE These safety precautions are for information purposes only The pre cautions are ancillary to the testing proce dures and are not intended to be all inclu sive It is the user s responsibility to use safe and proper techniques in handling materials in this test method Manufac turers MUST be consulted for specific details such as material safety data sheets and other manufacturer s recommenda tions All OSHA standards and rules must also be consulted and followed 4 1 Good laboratory practice should be followed Wear safety glasses in all labo ratory areas 4 2 When handling glacial acetic acid to prepare Nash reagent use chemical goggles or face shield impervious gloves and an impervious apron during prepara tion Concentrated acids should be han dled only in an adequately ventilated lab oratory hood CAUTION Always add acid to water 4 3 Formaldehyde is a sensory irritant and potential sensitizer Its chronic toxic ity has not been fully established Use in an adequately ventilated laboratory hood Avoid inhalation or skin contact Use chemical goggles or face shield impervi ous gloves and an impervious apron when working with formaldehyde see 8 1 4 4 An eyewash safety shower should be located nearby and a self contained breathing apparatus should be readily available for emergency use 4 5 Exposure to chemicals used in this procedure must be controlled at or below levels set by governmental authorities e g Occupational Safety and Health Administration s OSHA permissible exposure limits PEL as found in 29 CFR 1910 1000 see web site www osha gov for latest version In ad dition the American Conference of Gov ernmental Industrial Hygienists ACGIH Threshold Limit Values TLVs com prised of time weighted averages TLV TWA short term exposure limits TLV STEL and ceiling limits TLV C are recommended as a general guide for air contaminant exposure which should be met see 13 7 5 Uses and Limitations 5 1 The procedure is intended for use in the range of releasable formaldehyde on hydrophobic and non hydrophobic fabrics up to about 3500 g g The upper limits are 500 g g if a 1 1 ratio of Nash reagent to sample solution is used in the analytical portion of the test and 3500 g g if a 10 1 ratio is used The procedure promotes formaldehyde release from odor free fully cured durable press fab rics that have been afterwashed Vail S L and B A K Andrews Textile Chemist and Colorist Vol 11 No 1 January 1979 p48 For these reasons the proce dure should not be used to estimate g g formaldehyde in air for compliance with any mandated or voluntary standards The procedure was originally developed to measure the propensity of a resin treated fabric to liberate an excessive amount of formaldehyde under hot hu mid conditions Nuessle A C Ameri can Dyestuff Reporter Vol 55 No 17 1966 pp48 50 also Reid J D R L Ar cenaux R M Reinhardt and J A Harris American Dyestuff Reporter Vol 49 No 14 1960 pp29 34 5 2 Alternatively Test Method 206 Free and Hydrolyzed Formaldehyde De termination of Water Extraction Method determines free and hydrolyzed formal dehyde on the fabric from 20 g g up to about 3500 g g This method approxi mates hydrolyzed formaldehyde and closely simulates normal user condi tions The appropriate test should be based on that distinction However since TM 206 is an aqueous immersion method fabrics with a propensity for dye bleeding could be of concern if the dye has an absorbance in the range of 412 nm it could interfere with the spectro photometer measurement TM 112 does not use aqueous immersion therefore there is less chance for dye contamination interfering with the spectrophotometer measurement 6 Apparatus and Materials 6 1 Clear glass jars Mason or equiva lent canning jars 0 95 L 1 qt and gas sealing caps These are clear square glass jars with approximate dimensions of 9 cm wide 17 cm tall contain approxi mately 1L and have a screw on lid 6 2 Small wire mesh baskets or other suitable means for suspending fabric above the water level inside the jars see 13 2 As an alternative to the wire mesh baskets a double strand of sewing thread may be used to make a loop in the fabric that has been folded in half twice sus pended above the water level The two double thread ends are draped over the top of the jar and held securely by the jar cap 6 3 Weighing balance with minimum AATCC TM112 2020 Test Method for Formaldehyde Release from Fabric Sealed Jar 30 2 AATCC TM112 2020 sensitivity of 0 01 g 6 4 Thermostatically controlled oven 49 1 C 120 2 F see 13 6 6 5 Nash reagent prepared from ammo nium acetate acetic acid and acetylace tone and water see 7 1 6 6 Formaldehyde solution approxi mately 37 6 7 Volumetric flasks 50 250 500 and 1000 mL Class A 6 8 Volumetric pipettes 5 10 15 20 25 30 and 50 mL volumetric pipettes all meeting Class A volume accuracy and flow time requirements see 13 3 Or a digital variable volume pipette capable of meeting Class A requirements 6 9 A 1 L clean brown glass bottle with lid 6 10 Spectrophotometer capable of reading absorbance to minimum of three decimal places at wavelength of 412 nm see 10 6 6 11 Test tubes see 13 3 6 11 Water bath general purpose and temperature controlled see 10 5 6 12 Distilled or deionized water Hereafter referred to as deionized water 7 Preparation of Nash Reagent 7 1 In a 1000 mL volumetric flask dis solve 150 0 0 1 g of ammonium acetate in about 800 mL of deionized water add 3 0 0 1 mL of glacial acetic acid and 2 0 0 1 mL of acetylacetone Make up to the mark with deionized water and mix Store in a capped brown bottle 7 2 The reagent darkens in color slightly on standing over the first 12 h For this reason the reagent should be held 12 h before use Otherwise the reagent is usable over a considerable period of time at least 6 8 weeks However since the sensitivity may change slightly over a long period of time it is good practice to run a calibration curve weekly to correct for slight changes in the standard curve 8 Preparation of Standard Solution and Calibration Caution 8 1 Prepare an approximately 1500 g mL stock solution of formaldehyde by di luting 3 8 0 1 mL of reagent grade formaldehyde solution approximately 37 to 1 0 liter with deionized water Equilibrate the stock solution for at least 24 h before standardization Determine the concentration of formaldehyde in the stock solution by a standard method see 13 5 or any other suitable procedure such as sodium sulfite titration using 0 1 N HCl Reference J Frederick Walker Formaldehyde 3rd Ed Reinhold Publ Co New York 1964 p486 An alter nate reference is the Analytical Methods for a Textile Laboratory Third Edition Record the actual concentration of this standardized stock solution This stock solution will keep for at least four weeks and is used to prepare standard dilutions A 1 10 dilution of the standardized form aldehyde stock solution is prepared by pi petting 25 0 0 03 mL of the standard ized stock solution into a 250 mL volumetric flask and diluting to the mark with deionized water When the stock so lution is titrated the concentration is de termined in g mL prepare the calibra tion curves by 8 1 1 Pipette 5 0 10 0 15 0 20 0 and 30 0 mL of the 1 10 dilution into a 500 mL volumetric flask and dilute to mark with deionized water If for example the standardized stock solution were found to be 1470 g mL by titration cal culate new values for the calibration curve abscissa i e 1 47 2 94 4 41 5 88 8 82 g mL using linear regression anal ysis 8 2 When 5 0 10 0 15 0 20 0 and 30 0 mL aliquots of the 1 10 dilution of the standardized stock solution from 8 1 are diluted with deionized water in 500 mL volumetric flasks formaldehyde so lutions containing approximately 1 5 3 0 4 5 6 0 and 9 0 g mL formaldehyde re spectively will be obtained Record accu rately the concentration of solutions The equivalent concentrations of the formal dehyde in the test fabric based on the weight of 1 0 g of the test fabric and 50 0 mL of water in the test jars will be 50 times the accurate concentrations of these standard solutions 8 3 Use 5 0 mL aliquots of each of the standard solutions and the procedure de scribed in 10 4 10 7 to prepare a calibra tion chart in which g mL formaldehyde are plotted against absorbance 9 Test Specimens 9 1 Samples should immediately be placed into separate zipper type closure plastic bags when sampled or cut from rolls As an extra precaution for main taining their original state the samples may be wrapped in aluminum foil before being placed in the plastic bags 9 2 Cut approximately 1 g specimens weigh each one to 0 01 g Perform in duplicate for each sample If there is a de lay in testing the 1 g specimens once they are cut they should be put back into the zipper type closure plastic bags and re wrapped in foil if previously done until testing commences 10 Procedures 10 1 Pipette 50 0 mL of deionized wa ter in the bottom of each jar Suspend one fabric specimen above the water in each jar using a wire mesh basket or other means see Fig 1 Seal the jars and place them in the oven at 49 1 C 120 2 F for 20 h 10 min see 13 6 A control of an empty basket no fabric in a jar with 50 mL of deionized water may also be used 10 2 Remove and cool the jars for at least 30 min 10 3 Remove the fabric and baskets or other support from the jars Recap the jars and shake them to mix any condensa tion formed on the jar sides 10 4 Pipette 5 0 mL of Nash reagent into a suitable number of test tubes then add 5 0 mL aliquots from each of the sample incubation jars to the tubes also Fig 1 The wire mesh basket detailed on the left is suspended in a sealed jar with one fabric specimen as shown on the right 31 AATCC TM112 2020 3 and 5 0 mL of deionized water to a tube and used as a reagent blank Perform du plicate solutions of each jar 10 5 Mix and place the tubes in a 58 1 C 136 2 F water bath for 6 min 15 sec Remove and cool 10 6 Read the absorbance in the spec trophotometer against the reagent blank using a wavelength of 412 nm CAUTION Exposure of the developed yellow color to direct sunlight for a period of time will cause some fading If there is appreciable delay in reading the tubes after color de velopment and strong sunlight is present care should be exercised to protect the tubes from light Otherwise the color is stable for considerable time at least overnight and reading may be delayed 10 7 Determine the g mL formalde hyde HCHO in the sample solutions us ing the prepared calibration curve see 8 3 and 13 3 11 Calculation 11 1 Calculate the amount of formalde hyde released for each specimen to the nearest g g using the following equation F C 50 W where F concentration of formaldehyde g g C concentration of formaldehyde in solution as read from the calibra tion curve and W weight of the test specimen g 12 Precision and Bias 12 1 Precision 12 1 1 Interlaboratory tests Two inter laboratory studies ILS of AATCC TM112 were conducted in 1990 and 1991 with a 20 h incubation at 49 C and a 5 5 sample to Nash solution ratio Single operators in each participating laboratory ran triplicate determinations on each fab ric In the first ILS results from nine labo ratories testing one fabric each at three low formaldehyde levels in the range of 100 400 g g were analyzed by analysis of variance ANOV A In the second ILS results from eight laboratories testing ten fabrics of nominal 0 g g were analyzed by ANOVA The analyses have been de posited for reference in the RA68 com mittee files 12 1 2 Critical differences were calcu lated for zero formaldehyde fabrics shown in Table I and for low level form aldehyde fabrics shown in Table II 12 1 3 When two or more laboratories wish to compare test results it is recom mended that laboratory level be estab lished between them prior to beginning test comparisons 12 1 4 If comparisons are made be tween laboratories on a single fabric level of formaldehyde release the critical dif ferences in the column single level in Table II should be used 12 1 5 If comparisons are made be tween laboratories on a series of fabrics of a range of formaldehyde levels the critical differences in the column multi ple levels in Table II should be used 12 1 6 The number of determinations per laboratory average det avg also de termines the critical difference 12 2 Bias 12 2 1 The formaldehyde release of a fabric can be defined only in terms of a test method There is no independent method for determining the true value As a means of estimating formaldehyde re leased from a fabric under the conditions of accelerated storage in AATCC TM112 the method has no known bias 12 2 2 AATCC TM112 generally is ac cepted by the textile and apparel indus tries as a referee method 13 Notes 13 1 Formaldehyde is a component of or precursor to many fabric finishes As part of the application the finish is cured resulting in self crosslinking of the finish and or crosslink ing of the finish with the fabric Incomplete crosslinking or hydrolysis in later storage can result in the presence of hydrolyzed formalde hyde on the fabric Warm moist conditions can further hydrolyze cross linked finishes and release more formaldehyde Test Method 112 determines free and hydrolyzed formalde hyde and additional formaldehyde collectively referred to as released formaldehyde as gen erate
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