1、Designation: E1826 11Standard Specification forLow Volatile Organic Compound (VOC) Corrosion-InhibitingAdhesive Primer for Aluminum Alloys to Be AdhesivelyBonded1This standard is issued under the fixed designation E1826; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense
3、.1. Scope1.1 This specification covers pigmented, sprayable, lowvolatile organic compound (VOC) corrosion-inhibiting adhe-sive primers for use on aluminum alloys that are to beadhesively bonded in the fabrication of panels for tacticalshelters. When applied to a properly prepared surface ofaluminum
4、alloy, the primer imparts corrosion resistance andforms a surface suitable for structural bonding and for coatingwith shelter paint finishes.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provi
5、ded for informa-tion only and are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bil
6、ity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray (Fog) ApparatusB209 Specification for Aluminum and Aluminum-AlloySheet and PlateD1002 Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Speci
7、mens by Ten-sion Loading (Metal-to-Metal)D3167 Test Method for Floating Roller Peel Resistance ofAdhesivesE864 Practice for Surface Preparation of Aluminum Alloysto Be Adhesively Bonded in Honeycomb Shelter PanelsE865 Specification for Structural Film Adhesives for Hon-eycomb Sandwich PanelsE874 Pra
8、ctice for Adhesive Bonding of Aluminum Facingsto Nonmetallic Honeycomb Core for Shelter Panels2.2 Federal Specifications:3QQ-A-250/8d Aluminum Alloy 5052 H34 Plate and SheetQQ-A-250/11d Aluminum Alloy 6061 T6 Plate and Sheet2.3 Government Document:4Rule 1124 Aerospace Assembly and Component Manufac-
9、turing Operations, South Coast Air Quality ManagementDistrict3. Materials and Manufacturer3.1 The primer shall be a pigmented liquid composed of amodified epoxy phenolic or other resin system compounded tobe spray-applied to produce a continuous, uniform coatingwithout dilution.4. Physical Propertie
10、s4.1 The uncured primer shall be tested as specified in 5.1and meet the requirement of Table 1.4.2 Properties of Cured FilmWhen applied and cured inaccordance with 5.1.8, the cured film shall meet the require-ments of Tables 2 and 3 when tested as specified in 5.2 and 5.3.4.3 Storage StabilityPrimer
11、 stored in accordance with5.1.3 shall meet the requirements for normal- and low-temperature floating roller peel in Table 3 when cured inaccordance with 5.1.8 and tested as specified in 5.3.7 and 5.3.8.4.4 Shelf LifeThe shelf life of the primer at 25 6 7C (776 12F) shall be at least four days.After
12、four days, when testedaccording to 5.1.4, the primer shall meet the requirements for1This specification is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.53on Materials and Processes for Durable Rigidwall Relocatable Struc
13、tures.Current edition approved May 1, 2011. Published May 2011. Originallyapproved in 1996. Last previous edition approved in 2005 as E1826 05. DOI:10.1520/E1826-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
14、ok of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.4Available from South Coast Air Quality Ma
15、nagement District, 21865 CopleyDr. Diamond Bar, CA 91765, http:/www.aqmd.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.normal- and low-temperature floating roller peel in Table 3when cured in accordance with 5.1.8 and tested as
16、 specified in5.3.7 and 5.3.8.4.5 Film ThicknessThe average, minimum, and maximumfilm thicknesses shall be between 0.0025 and 0.010 mm(0.0001 and 0.0004 in.) 615 % coefficient of variation.At leastfive thickness readings shall be made with no more than one inany 645 mm2(1 in.2) area.4.6 VOC ContentTh
17、e volatile organic compound (VOC)is any volatile compound containing the element of carbon,excluding methane, carbon monoxide, carbon dioxide, car-bonic acid, metallic carbides or carbonates, and ammoniumcarbonates, as stated in Rule 1124. The VOC content shallmeet the requirement in Table 1 when de
18、termined in accor-dance with 5.1.9.5. Test Methods5.1 Uncured Primer:5.1.1 Solids ContentDetermine the solids content by heat-ing a 2-g sample of thoroughly mixed primer in an ignition-losscrucible with cover at 121 6 5C (250 6 9F) for not less than90 min. Cool the crucible to room temperature in a
19、desiccator.Weighings before and after heating shall be accurate to 60.001g. Calculate the mass of solids remaining as a percentage of theinitial sample mass as follows:Percent solids content 5mass of nonvolatile residueinitial sample mass3 100 (1)5.1.2 Ash ContentPlace the crucibles containing the s
20、ol-ids content samples in a furnace at 565 6 28C (1050 6 82F)for not less than 60 min. Cool the crucible to room temperaturein a desiccator. Weighings before and after heating shall beaccurate to 60.001 g. Calculate the ash content remaining as apercentage of the solids content as follows:Percent as
21、h content 5mass of ash residuemass of nonvolatile residue3 100 (2)5.1.3 Storage StabilityStore a sample of the primer forthree months from the date of manufacture at a temperaturerecommended by the manufacturer. The stored sample shallmeet the requirements for normal- and low-temperature float-ing r
22、oller peel in Table 3 when cured in accordance with 5.1.8and tested as specified in 5.3.7 and 5.3.8.5.1.4 Shelf LifeStore a sample of the primer for four daysat 25 6 7C (77 6 13F). The aged sample shall meet therequirements for normal- and low-temperature floating rollerpeel in Table 3 when cured in
23、 accordance with 5.1.8 and testedas specified in 5.3.7 and 5.3.8.5.1.5 Film ThicknessThe cured primer film thicknessshall be determined with a eddy-current instrument as specifiedin 5.2.2.5.1.6 ColorDuring spray application, there shall be adiscernible color change for the primer thickness specified
24、 in4.5.5.1.7 SprayabilityThe primer shall be capable of beingreadily applied in accordance with the manufacturers instruc-tions to all test panels of either 6061 T6 or 5052 H34 aluminumalloy (Fed. Spec. QQ-A-250/11d or QQ-A-250/8d, respec-tively, or Specification B209) and cleaned in accordance with
25、Practice E864 for each of the tests described in 5.1.8-5.3.8.5.1.8 Curing PropertiesTest the cured film for the abilityto meet the requirements listed in Tables 2 and 3. Spray theprimer onto the test panels and air dry at least 20 min at 24 65C (77 6 9F); then heat in air for 65 6 5 min at 121 6 5C(
26、250 6 9F).5.1.9 VOC ContentThe grams of VOC per litre of primer,less water and exempt compounds per Rule 1124, shall bedetermined by the adhesive primer manufacturer in accordancewith Rule 1124 and meet the requirement for VOC content inTable 1.5.2 Cured Film:5.2.1 Test Panels and Panel PreparationT
27、est panels shallbe either 6061 T6 or 5052 H34 bare aluminum alloy (Fed.Spec. QQ-A-250/11d or QQ-A-250/8d, respectively, or Speci-fication B209) and cleaned in accordance with Practice E864.5.2.2 Smooth Uniform CoatingClean a 30- by 30-cm (12-by 12-in.) panel, spray to a primer thickness as specified
28、 in 4.5,and cure as specified in 5.1.8. Determine the primer thicknesswith a Fisher isoscope MP2-T3.3B (or equivalent) calibratedwith standards between 0.0025 and 0.010 mm (0.0001 and0.0004 in.). The primer thickness shall meet the requirementsin 4.5 and Table 2.5.2.3 Pencil HardnessDetermine the pe
29、ncil hardness ofthe cured film using the following procedure:5.2.3.1 Preparation of PencilsPrepare a set of drawingpencils ranging in hardness from 6B to 5H by stripping thewood away from the end approximately 10 mm (38 in.) withoutdamaging the lead. Square the tip of the lead by holding thepencil i
30、n a vertical position and moving the lead back and forthover 400-grit or finer abrasive paper. Square the tip of the leadafter each trial.5.2.3.2 ProcedurePlace a test panel with the cured primerapplied in a horizontal position. Push pencils of increasingTABLE 1 Physical Properties of Uncured Liquid
31、 PolymerTest RequirementSolids content,% Report onlyAsh content, % Report onlyColor Easily visible filmVOC content 250 g/L maxTABLE 2 Physical Property of Cured Film on Primed SurfacesTest RequirementSmooth uniform coating 0.0025 to 0.010 mm (0.0001 to 0.0004in.)6 15 % coefficient of variationTABLE
32、3 Physical Properties of Bonded SpecimensTestRequirements(min)Normal-temperature lap shear, 24C (77F), MPa (psi) 20.0 (2903)Low-temperature lap shear, 55C (67F), MPa (psi) 20.0 (2903)High-temperature lap shear, 93C (200F), MPa (psi) 13.0 (1890)Humidity exposure lap shear, 93C (200F), MPa (psi) 8.0 (
33、1161)Salt spray exposure lap shear, 35C (95F), MPa (psi) 16.0 (2322)Normal-temperature floating roller peel strength, 24C (75F),N/m (lbf/in.)4400 (25.1)Low-temperature floating roller peel strength, 55C (67F),N/m (lbf/in.)2625 (15.0)E1826 112hardness at a 45 angle into the coated surface of the pane
34、l untilone is found that will cut or scratch the coating. Use thenumber of this pencil to express the primer hardness.5.2.4 Environmental Resistance TestClean three test pan-els for each test described in 5.2.5-5.2.7 approximately 76 by127 mm (3 by 5 in.) in accordance with 5.2.1.Apply the primerand
35、 cure in accordance with 4.5 and 5.1.8. The primed panelsshall be subjected to the environments specified in 5.2.5-5.2.7and there shall be no cracking, no blistering, and a minimumpencil hardness of 4H.5.2.5 Water ResistanceImmerse the panels with the curedprimer coating in distilled water for seven
36、 days at 24 6 3C (756 5F) and then expose to 95 to 100 % relative humidity at 506 3C (121 6 5F) for 30 days.After exposure the panels shallmeet the requirements in 5.2.4, and there shall be no loss ofadhesion as described in 5.2.8.5.2.6 Heat ResistanceHeat test panels prepared as in 5.2.4at 120 6 3C
37、 (248 6 5F) for 70 h. After exposure the panelsshall meet the requirements in 5.2.4, and there shall be no lossof adhesion as described in 5.2.8.5.2.7 Corrosion ResistanceScribe test panels prepared inaccordance with 5.2.4 through the coating to the base metalwith two diagonal scribe marks extending
38、 from corner tocorner and then expose them to 5 % salt fog in accordance withPractice B117 for 40 days.After exposure the panels shall meetthe requirements in 5.2.4, and there shall be no undercutting ofthe primer along the scribe lines.5.2.8 Loss of Adhesion:5.2.8.1 Thoroughly dry the panel by wipi
39、ng with a clean drycheesecloth. Conduct the test at 20 to 27C (68 to 81F).5.2.8.2 Scribe two parallel scratches 25 mm (1 in.) apartthrough the coating down to the metal with a sharp edgedscribe.5.2.8.3 Apply a strip of 25-mm (1-in.) wide masking tape(not more than five months old from date of manufa
40、cture)across the scratches at 90 to the scribe lines in the panel areato be tested. Press the tape down using two passes of a 2-kg(4.4-lb) rubber-covered roller approximately 90 mm (3.5 in.) indiameter by 44.5 mm (1.75 in.) in width. The durometer of theroller surface shall be 70 to 80 Shore A.5.2.8
41、.4 As an alternative to 5.2.8.3, the tape shall be presseddown by rolling the tape roll along the strip of applied tapeusing a firm hand pressure of approximately 2 kg (4.4 lb).5.2.8.5 Remove the tape in one abrupt motion perpendicularto the panel. No primer shall be removed from the panel, othertha
42、n that previously removed during the scribing procedure in5.2.8.2.5.3 Bonding Property Tests:5.3.1 Preparation of Test SpecimensPrepare five speci-mens in accordance with Practice E864 for each of the tests inTable 3. The lap shear specimens shall be in accordance withTest Method D1002 and the peel
43、specimens in accordance withTest Method D3167. The adherents shall be of either 6061 T6or 5052 H34 aluminum alloy (Fed. Spec. QQ-A-250/11d orQQ-A-250/8d, respectively, or Specification B209). Apply theprimer and allow to air dry for not less than 20 min at 25 6 5C(78 6 9F); follow by heating at 121
44、6 5C (250 6 9F) for65 6 5 min. Bond and cure in accordance with SpecificationE865.5.3.2 Normal-Temperature Lap ShearSubject each speci-men to a lap shear test at 25 6 3C (77 6 5F) in accordancewith Test Method D1002.5.3.3 Low-Temperature Lap ShearTest each specimen inaccordance with Test Method D100
45、2 for low-temperature lapshear at 55 6 3C (66 6 5F). Bring the temperature of thespecimen to 55 6 3C (66 6 5F) as indicated by athermocouple at the bond area and stabilize for 10 min prior totest. The test chamber used to test the specimens shall bestabilized at the test temperature for at least 45
46、min prior totesting.5.3.4 High-Temperature Lap ShearTest each specimen inaccordance with Test Method D1002 for high-temperature lapshear at 93 6 3C (200 6 5F). Bring the temperature of thespecimen to 93 6 3C (200 6 5F) as indicated by athermocouple at the bond area and stabilize for 10 min prior tot
47、est. The test chamber used to test the specimens shall bestabilized at the test temperature for at least 45 min prior totesting.5.3.5 Humidity Exposure Lap ShearTest each specimen inaccordance with Test Method D1002 at 93 6 3C (200 6 5F)for lap shear strength after two weeks exposure at 95 6 5%relat
48、ive humidity at 71 6 3C (160 6 5F).After removing thespecimens from the humidity cabinet, place them and a wetpaper towel in a sealed plastic bag. Bring the temperature ofthe specimen to 93 6 3C (200 6 5F) as indicated by athermocouple at the bond area. Stabilize the specimen 2 minprior to test. Tes
49、t the specimens within 24 h after removal fromthe humidity cabinet. The test chamber used to test thespecimens shall be stabilized at the test temperature for at least45 min prior to testing.5.3.6 Salt Spray Exposure Lap Shear Test each specimenin accordance with Test Method D1002 after exposure for twoweeks to salt spray using 5 % NaCl solution at 35 6 1C (956 2F) in accordance with Practice B117.5.3.7 Normal-Temperature Floating Roller Peel StrengthTest each specimen in accordance w
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