1、Designation: D3184 11 (Reapproved 2018)Standard Practice forRubberEvaluation of NR (Natural Rubber)1This standard is issued under the fixed designation D3184; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the standard materials, testformulas, mixing procedures, and test methods for the evalu-ation and production
3、control of natural rubber (NR).1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.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
4、 this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the
5、Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD
6、1485 Practice for Rubber from Natural SourcesSampling and Sample PreparationD1646 Test Methods for RubberViscosity, StressRelaxation, and Pre-Vulcanization Characteristics(Mooney Viscometer)D2084 Test Method for Rubber PropertyVulcanizationUsing Oscillating Disk Cure MeterD3182 Practice for RubberMa
7、terials, Equipment, and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Significance and Use3.1 This practice is mainly intended for referee purp
8、oses butmay be used for quality control of rubber production. It mayalso be used in research and development work and forcomparison of different rubber samples in a standard formula.4. Standard Test Formulas4.1 Standard Formulas:Quantity, Parts by Mass, and Formula No.MaterialIndustryReferenceMateri
9、al No.1A Gum 2A BlackFilled3AAGumNatural rubber . 100.00 100.00 100.00Zinc oxide 091 6.00 5.00 6.00Sulfur 031 3.50 2.25 3.50Stearic acid 021 0.50 2.00 0.50Oil furnaceblackBIRB#7 . 35.00 .Mercaptobenzothiazole 002 0.50 . .TBBSC003 . 0. 70 0.70Total 110.50 144.95 110.70Batch factor:DMill 3.0 3.0 3.0Mi
10、niature internalmixer:ECam Head 0.57 0.48 0.57Banbury Head 0.50 0.42 0.50ARecommended formula for Test Method D2084 vulcanization characteristicsusing oscillating disk cure meter.BThe current Industry Reference Black may be used in place of NIST 378,although slightly different results may be obtaine
11、d.CN-tert-butyl-2-benzothiazole sulfenamide.DFor mill mixes, weigh the rubber and carbon black to the nearest 1.0 g, the sulfurand accelerators to the nearest 0.02 g, and all other compounding materials to thenearest 0.1 g.EFor MIM batches weigh the rubber carbon black to the nearest 0.1 g, thecompo
12、unding material blend to the nearest 0.01 g, and individual compoundingmaterials, if used, to the nearest 0.001 g. For the MIM procedure, it is recom-mended that a blend of compounding materials, including black, be prepared toimprove accuracy in the weighing of these materials. This material blend
13、is pre-pared by blending a proportional mass of each material in a dry powder such as abiconical blender or vee blender. A mortar and pestle may be used for blendingsmall quantities.5. Sample Preparation5.1 For tests intended for referee purposes obtain andprepare the samples in accordance with Test
14、 Methods D1485.1This practice is under the jurisdiction of ASTM Committee D11 on Rubber andRubber-like Materials and are the direct responsibility of Subcommittee D11.22 onNatural Rubber.Current edition approved June 1, 2018. Published August 2018. Originallyapproved in 1973. Last previous edition a
15、pproved in 2011 as D3184 11. DOI:10.1520/D3184-11R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyrigh
16、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International
17、 Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16. Mixing Procedures6.1 The following three mixing procedures are offered asfollows:6.1.1 Mill Method AFor gum formulas 1A and 3A.6.1.2 Mill Method BFor black formula 2A.6.1.3 M
18、IM Method CFor formula 1A, 2A, and 3A.NOTE 1It is not implied that comparable results will be obtained bythese test methods.6.2 Mill Method A:6.2.1 For general mixing procedures, refer to PracticeD3182.6.2.2 Mixing shall be done with the mill roll temperaturemaintained at 70 6 5C (158 6 9F). The ind
19、icated millopenings are desired and should be maintained insofar aspossible to provide a standard for uniform breakdown of therubber due to milling.6.2.3 Mixing CycleGum Compound:Dura-tion,minAccumu-lative,minSet the mill opening at 0.20 mm (0.008 in.) and pass therubber through the rolls twice with
20、out banding.11Band with the mill opening at 1.40 mm (0.055 in.) andbreak down, opening the mill to 1.90 mm (0.075 in.) asthe band becomes smooth.45Add the stearic acid. 2 7Add the zinc oxide, sulfur, and accelerator. 4 11Make three34 cuts from each side. 2 13Cut the stock from the mill. Set the open
21、ing at 0.80 mm(0.032 in.) and pass the rolled stock endwise through themill six times.215Open the mill to give a minimum stock thickness of 6mm (0.25 in.) and pass the stock through the rolls fourtimes, folding it back on itself each time.318_ _Total Time 186.2.3.1 Check the batch mass and record. I
22、f it differs fromthe theoretical value by more than 0.5 %, reject the batch.6.2.3.2 From this stock, cut enough sample to allow testingof compounded viscosity in accordance with Test MethodsD1646 or curing characteristics in accordance with TestMethod D2084, or both, if these are desired. Sheet off
23、the stockfrom the mill at a setting to give an approximate finish gage of2.2 mm (0.085 in.). Cool on a flat, dry metal surface.6.2.3.3 For routine laboratory testing, condition the sheetedcompound for 1 to 24 h at 23 6 2C (73.4 6 3.6F) and arelative humidity not greater than 55 %. For maximumprecisi
24、on, condition for 1 to 24 h in a closed container toprevent absorption of moisture from the air or in an areacontrolled at 35 6 5 % relative humidity.6.3 Mill Method B:6.3.1 For general mixing procedures, refer to PracticeD3182.6.3.2 Mixing shall be done with the mill roll temperaturemaintained at 7
25、0 6 5C (158 6 9F). The indicated millopenings are desired and should be maintained insofar aspossible to provide a standard for uniform breakdown of therubber due to milling.6.3.3 Mixing CycleBlack-Filled Compound:Dura-tion,minAccumu-lative,minSet the mill opening at 0.20 mm (0.008 in.) and pass the
26、rubber through the rolls twice without banding.11Band the rubber on the front roll with the mill opening at1.40 mm (0.055 in.). Make two34 cuts from each side.23NOTE 1Do not cut any stock while free carbon black is evident in thebank or on the milling surface. Be certain to run any pigments that dro
27、pthrough the mill to the milling stock.Dura-tion,minAccumu-lative,minSet the mill opening at 1.70 mm (0.067 in.). Add zincoxide. Make one34 cut from each side.25Add the carbon black evenly across the mill at a uniformrate. When about half the black is incorporated, add thestearic acid and open the m
28、ill to 1.90 mm (0.075 in.).Make one34 cut from each side then add the remainderof the carbon black.14 19Add the accelerator, taking care to avoid any loss.Sweep the mill pan and add until all the pigment is in thebatch. Make three34 cuts from each side.221Add the sulfur and that which falls into the
29、 mill pan.Make one34 cut from each side.324Cut the stock from the mill. Set the opening at 0.80 mm(0.032 in.) and pass the rolled stock endwise through themill six times.226Open the mill to give a minimum stock thickness of 6mm (0.25 in.) and pass the stock through the rolls fourtimes, folding it ba
30、ck on itself each time.329_ _Total Time 296.3.3.1 Check the batch mass and record. If it differs fromthe theoretical value by more than 0.5 % reject the batch.6.3.3.2 From this stock, cut enough sample to allow testingof compounded viscosity in accordance with Test MethodsD1646, or curing characteri
31、stics in accordance with TestMethod D2084, or both, if these are desired. Sheet off the stockfrom the mill at a setting to give an approximate finish gage of2.20 mm (0.085 in.). Cool on a flat, dry metal surface.6.3.3.3 For routine laboratory testing, condition the sheetedcompound for 1 to 24 h at 2
32、3 6 2C (73.4 6 3.6F) and arelative humidity not greater than 55 %. For maximumprecision, condition for 1 to 24 h in a closed container toprevent absorption of moisture from the air or in an areacontrolled at 35 6 5 % relative humidity.6.4 Method CMiniature Internal Mixer Mix:6.4.1 For general mixing
33、 procedure, refer to PracticeD3182. Mix with the head temperature of the miniatureinternal mixer maintained at 60 6 3C (140 6 5F) and theunloaded rotor speed at 6.3 to 6.6 rad/s (60 to 63 rpm).6.4.2 Prepare the rubber by passing it through a mill onetime with the temperature set at 50 6 5C (122 6 9F
34、) and anopening of 0.5 mm (0.02 in.) thick. Cut the sheet into strips thatare approximately 25 mm (1 in.) wide if desired.6.4.3 Mixing Cycle:Dura-tion,minAccumu-lative,minCharge the mixing chamber with the rubber strips and theblended materials, lower the ram, and start the timer.00Allow to mix. 1 1
35、Raise the ram, add carbon black, sweep the orifice, andlower the ram.12Allow the batch to mix, raising the ram momentarily tosweep down the materials, if necessary.35D3184 11 (2018)26.4.3.1 Turn off the motor, raise the ram, remove the headand discharge the batch. Measure and record the maximumbatch
36、 temperature if desired.6.4.3.2 Immediately pass the batch twice through a labora-tory mill maintained at 50 6 5C (122 6 9F) and with the rollseparation of 3 mm (0.125 in.).6.4.3.3 Check the batch mass and record. If it differs fromthe theoretical value by more than 0.5 %, discard the batch.6.4.3.4
37、Cut a specimen for testing vulcanization character-istics in accordance with Test Method D2084, if required.Condition the specimen for 1 to 24 h at 23 6 3C (73.4 65.4F) before testing.6.4.3.5 If either compound viscosity or stress-strain testingis required, pass the rolled compound end-wise through
38、themill six times with the mill rolls set at 50 6 5C (122 6 9F)and 0.8 mm (0.032 in.).6.4.3.6 Cut a specimen to allow testing for compoundviscosity in accordance with Test Methods D1646, if required.6.4.3.7 If tensile stress is required, sheet off the compoundfrom the mill at a setting to give a fin
39、ished gage of approxi-mately 2.2 mm (0.085 in.) by passing the folded stock betweenthe rolls set at 50 6 5C (122 6 9F) four times always in thesame direction to obtain the effects of mill direction. Cool ona flat, dry metal surface.6.4.3.8 For routine laboratory testing, condition the sheetedcompoun
40、d for 1 to 24 h at 23 6 3C (73.4 6 5.4F) and arelative humidity not greater than 55 %. For maximumprecision, condition for 1 to 24 h in a closed container toprevent absorption of moisture from the air or in an areacontrolled at 35 6 5 % relative humidity.7. Preparation and Testing of Vulcanizates7.1
41、 For stress-strain testing, prepare test slabs and vulcanizethem in accordance with Practice D3182.7.1.1 The recommended standard cure times are 10, 20, 40,and 80 min at 140C (284F).7.1.2 Condition the cure sheets for 16 to 96 h at a tempera-ture of 23 6 2C (73.4 6 3.6F).NOTE 2Quality control of pro
42、duction may require testing within 1 to6 h, to provide close surveillance of the plant operations; however, slightlydifferent results may be obtained.7.1.3 Prepare test specimens in accordance with PracticeD3182 and obtain modulus, tensile, and elongation parametersin accordance with Test Methods D4
43、12.7.2 An alternative to measuring stress-strain properties ofvulcanizates is the cure meter measurement of vulcanizationparameters in accordance with Test Method D2084.7.2.1 The recommended standard test conditions are 1.7 Hz(100 cpm) oscillation frequency, 1 6 0.03 amplitude ofoscillation, and 160
44、 6 0.3C (320 6 0.5F) die temperature.7.2.2 The recommended standard test parameters are ML,MH, tS1, t (50), and t (90). For formula 3A, use MHFinstead ofMH.8. Keywords8.1 mill method; miniature mixer; mixing procedures; natu-ral rubber; sample preparation; test methodsASTM International takes no pos
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