1、Designation: F 2468 05Standard Classification forSpecifying Silicone Adhesives and Sealants forTransportation Applications1This standard is issued under the fixed designation F 2468; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This classification covers silicone adhesives and seal-ants intended for but not limited to sealing and r
3、etainingmetallic and nonmetallic component assemblies in transporta-tion applications. The materials cure to an elastomeric state bytheir specified cure system and mechanism.NOTE 1The classification system may serve many of the needs ofindustries using silicone materials. This classification is subj
4、ect torevision, as the need requires; therefore, the latest revision should alwaysbe used.1.2 This classification is intended to be a means of classi-fying silicone materials. It is not intended for engineeringdesign purposes.1.3 It is not the intent of this classification to includepressure-sensiti
5、ve or hot-melt adhesives.1.4 In all cases in which the provisions of this classificationsystem would conflict with the referenced ASTM standard fora particular method, the latter shall take precedence.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parenthese
6、s are for informationonly.1.6 The following safety hazards caveat pertains only to thetest methods portion, Section 7, of this classification. Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to
7、establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C 679 Test Method for Tack-Free Time of ElastomericSealantsD 149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of
8、Solid Electrical Insulating Materialsat Commercial Power FrequenciesD 150 Test Methods for AC Loss Characteristics and Per-mittivity (Dielectric Constant) of Solid Electrical Insula-tionD 257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD 412 Test Methods for Vulcanized Rubber
9、 and Thermo-plastic ElastomersTensionD 471 Test Method for Rubber PropertyEffect of LiquidsD 573 Test Method for RubberDeterioration in an AirOvenD 618 Practice for Conditioning Plastics for TestingD 624 Test Method for Tear Strength of ConventionalVulcanized Rubber and Thermoplastic ElastomersD 792
10、 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD 907 Terminology of AdhesivesD 1002 Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Ten-sion Loading (Metal-to-Metal)D 1053 Test Methods for Rubber Property
11、Stiffening atLow Temperatures Flexible Polymers and Coated FabricsD 1084 Test Methods for Viscosity of AdhesivesD 1349 Practice for RubberStandard Temperature forTestingD 1415 Test Method for Rubber PropertyInternationalHardnessD 1566 Terminology Relating to RubberD 1898 Practice for Sampling of Pla
12、stics3D 2240 Test Method for Rubber PropertyDurometerHardnessD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized SheetsD 4800 Guide for Classifying and Specifying Adhesives1This classification is under the jurisdiction of AST
13、M Committee F03 onGaskets and is the direct responsibility of Subcommittee F03.30 on Classification.Current edition approved March 1, 2005. Published March 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book o
14、f ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.2 SAE Standard:4SAE J369 Flammability of Polymeric Interior MaterialsHor
15、izontal Test Method2.3 UL Standard:5UL 94 Flammability3. Terminology3.1 DefinitionsSome terms in this classification are de-fined in Terminiologies D 907 and D 1566.3.2 Definitions of Terms Specific to This Standard:3.2.1 cure mechanismthe method of initiating the cure fora silicone material.3.2.2 c
16、ure systemthe cross-linking mechanism the sili-cone material uses to transition to the elastomeric state.3.2.3 draw-downa method of sample preparation of vis-cous and sag-resistant sealants, in which the sealant is leveledusing a knife or tool to a specified thickness.3.2.4 formed in place gasket, f
17、ipga one- or two-component adhesive or sealant applied wet, uncured, to a jointsurface where the mating parts are assembled before the curingprocess is complete. When fully cured it forms a barrier tomedia migration across the joint.3.2.5 sag resistancea property of some adhesives andsealants that e
18、nables the applied or extruded material to retainits shape before curing or cross-linking.3.2.6 thixotropica rheological property of uncured seal-ants in which the sealant resists sagging or slumping unlessdisturbed by an external force or pressure.3.2.7 transportationany transportation venue involv
19、ingland, sea, or air, civilian or military, stationary and smallengines.3.2.8 volatileslow molecular weight components of anadhesive or sealant that can be extracted by the environment ofthe application.4. Significance and Use4.1 The purpose of this classification system is to provide amethod of ade
20、quately identifying silicone adhesives and seal-ants through the use of a line call-out designation.4.2 This classification system was designed to permit theaddition of property values for future silicone adhesives andsealants.5. Classification5.1 A ten-digit numbering system is used to classify asi
21、licone adhesive and sealant cure system, cure mechanism,application rate, tack free time; ultimate elongation, tensilestrength; blowout resistance, lap shear bond strength, specificgravity, and silicone volatile content as defined in Table 1. Thefirst column (left side of the table) indicates the di
22、git number ororder sequence required while the designation numbers foreach property are indicated on the top of the table. The ten-digitclassification number must also be separated with hyphensbetween the fourth and fifth digit, and the sixth and seventhdigit as seen in Example 1 (5.1.1).4Available
23、from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001.5Available from Underwriters Laboratories (UL), Corporate Progress, 333Pfingsten Rd., Northbrook, IL 60062.TABLE 1 Minimum Classification RequirementsSelectionOrderSequenceProperty Designation12 3 4 5 6 7891st
24、Digit Cure system(Cure by-product)Addition(no by-product)Acetoxy(aceticacid)Alkoxy(methanol,ethanol)Amine(cyclo-hexylamine)Enoxy(acetone)Oxime(methyl ethylketoxime)Freeradical. Asspecified2ndDigit Cure mechanism One-partmoisturecureTwo-partmoisturecureOne-partradiationcureAOne-partradiation-moisture
25、cureOne-partthermalcureTwo-partthermalcureRadiation . Asspecified3rdDigit Application rate, g/min 999 Asspecified4thDigit Test Method C 679,Tack free time, min60 Asspecified5thDigit Test Methods D 412 (Die C)Ultimate elongation, %999 . Asspecified6thDigit Test Methods D 412,Tensile strength, MPa14 A
26、sspecified7thDigit Blowout resistance,Bs 60 . Asspecified8thDigit Test Methods D 792,Specific gravity, g/cc1.5 Asspecified9thDigit Test Method D 1002,CLap shear bondstrength, MPa14 Asspecified10thDigit Silicone volatileContent, %10 AsspecifiedAUltraviolet light (UV), microwave, or visible light cure
27、.BResistance to blowout refers to the time to failure at a standardized internal pressure using a fixture as agreed upon between producer and user.CStandard test conditions: 5 cm (1.97 in.)/min cross head speed, 1 mm (0.039 in.) gap, 1.27 cm (0.50 in.) overlap, Q panel 20204T3 Aluminum (as received)
28、.F24680525.1.1 Example 1To specify a silicone adhesive or sealantwith an acetoxy cure system, two-part moisture cure mecha-nism, application rate of 150 g/min, tack free time of 8 min,400 % ultimate elongation, 1.2 MPa tensile strength, 15 sblowout resistance, 1.1 specific gravity, 2.0 MPa lap shear
29、bond strength, and 2.5 % silicone volatile, the line call-outwould be:ASTM F 2468, 223224422454where:2 = the acetoxy cure system,2 = the two-part moisture cure,3 = application rate between 100 and 199 g/min,2 = tack free time between 5 and 9.9 min,4 = ultimate elongation between 300 and 499 %,4 = te
30、nsile strength between 1.036 and 1.380 MPa,2 = blowout resistance between 10 and 20 s,4 = specific gravity between 1.06 and 1.15 g/cc,5 = lap shear strength between 1.381 and 3.45 MPa, and4 = silicone volatile content between 2.0 and 2.9 %.6. Line Call-Outs6.1 A “line call-out,” which is a specifica
31、tion, shall containthe ASTM classification number F 2468, a ten-digit prefixspecifying the cure system, cure mechanism, application rate,tack free time, ultimate elongation, tensile strength, blowoutresistance, specific gravity, lap shear bond strength, and sili-cone volatile content. This shall be
32、followed by appropriatesuffixes per Section 12 as agreed upon between producer anduser.7. General Requirements7.1 General requirements are properties that are inherent inevery lot of silicone produced but may be tested in accordancewith the line call-out at a frequency agreed on by the producerand u
33、ser to verify specification conformance.7.2 SuffxesWhen using the line call-out for materialscovered by this classification, the suffixes found in Table 2shall be used to detail specific requirements needed for theapplication intended and as agreed upon between producer anduser. In general, the suff
34、ix letter gives the test condition and thesecond digit gives the specific requirement.TABLE 2 Suffix Symbols and RequirementsSymbol CharacteristicA HEAT RESISTANCETest Method D 573First digitSee Table 3 for time designation.Second digitSee Table 3 for temperature designation.Third digitSee Table 4 f
35、or hardness change designation.Fourth digitSee Table 4 for tensile change designation.Fifth digitSee Table 4 for elongation change designation.Sixth digitSee Table 4 for volume change designation.C CORROSIVITYSecond letterA = CopperB=SteelC = AluminumThree-digit number001=0=testmethodtobespecified b
36、y user.1 = no permanent discoloration of the metals that does not buff off with anonabrasive cloth.D ELECTRICAL (dielectric/resistance properties)TABLE 2 ContinuedSymbol CharacteristicSecond letterA = dielectric strength (short time), Test Method D 149Three-digit number x factor of 0.1 = kV/mm, minB
37、 = dielectric strength (step by step), Test Method D 149Three-digit number x factor of 0.1 = kV/mm, minC = insulation resistance, Test Methods D 257Three-digit number x factor of 106= V,minD = dielectric constant at 1 MHz, Test Methods D 150, maxThree-digit number x factor of 0.1 = valueE = dissipat
38、ion factor at 1 MHz, Test Methods D 150, maxThree-digit number x factor of 0.0001 = valueE FLUID RESISTANCETest Method D 471Second letterA = ASTM #1 OilB = IRM 902 OilC = IRM 903 OilD = ASTM SF105E = ASTM B FuelF = ASTM C FuelQ = as specifiedFirst digitSee Table 3 for time designation.Second digitSe
39、e Table 3 for temperature designation.Third digitSee Table 4 for hardness change designation.Fourth digitSee Table 4 for tensile change designation.Fifth digitSee Table 4 for elongation change designation.Sixth digitSee Table 4 for volume change designation.F LOW TEMPERATURETest Methods D 1053G TEAR
40、 STRENGTHTest Method D 624Second letterB = Die “B”C = Die “C”First digitSee Table 3 for time designation.Second digitSee Table 3 for temperature designation.H HARDNESSSecond letterA = Test Method D 2240B = Test Method D 1415First digitSee Table 3 for time designation.Second digitSee Table 3 for temp
41、erature designation.L COLORSecond letterA = does not have to match a standardB = as agreed upon between producer and userM FLAME RETARDANTSecond letterA=UL 94First digit indicated minimum specimen thickness, mm0 to be specified1 0.252 0.403 0.804 1.605 2.506 3.007 6.008 12.709 12.70Second digit indi
42、cates type of flame test1 = vertical (94 V)2 = horizontal (94 H)3 = 125-mm flame (94 to 95 V)4 = vertical thin materials (94 VTM)Third digit indicates the flame rating0 = (94 V/94 VTM) 0 refer to UL 941 = (94 V/94 VTM) 1 refer to UL 942 = (94 V/94 VTM) 2 refer to UL 943 = (94HB) 1 burn rate, 15009 =
43、 As specifiedV VISCOSITYSecond letterA = Test Methods D 1084, Method B, using an RVT viscometerB = Test Methods D 1084, Method B, using an LVT viscometerFirst digit indicates spindle numberFor RVT(A) For LVT(B)0 = As specified 0 = As specified1 = RV spindle #1 1 = LV spindle #12 = RV spindle #2 2 =
44、LV spindle #23 = RV spindle #3 3 = LV spindle #34 = RV spindle #4 4 = LV spindle #45 = RV spindle #56 = RV spindle #67 = RV spindle #7Second digit indicates spindle speedFor RVT(A) For LVT(B)0 = As specified 0 = As specified1=RV0.5RPM 1=LV0.3RPM2=RV1.0RPM 2=LV0.6RPM3=RV2.0RPM 3=LV1.5RPM4=RV4.0RPM 4=
45、LV3.0RPM5=RV5.0RPM 5=LV6.0RPM6=RV10RPM 6=LV12RPM7=RV20RPM 7=LV30RPM8=RV50RPM 8=LV60RPM9 = RV 100 RPMThird digit indicates viscosity in centipoise (cP)0 = As specified1=$50 but 100 As specifiedATable 4 indicates a maximum change from an original test value and is not an absolute value.As such, when a “% maximum change” is indicated, this is the plus/minusrange of variation the user would anticipate from the initial value after timed exposure to the temperature or the fluid indicated, or both.F2468055
