1、Designation:D 3192-97Standard Test Methods forCarbon Black Evaluation in NR(Natural Rubber)1This standard is issued under the fixed designation D3192:the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number
2、in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scopecarbon black production.They may also be used for the1.1 These test methods cover the standard materials,testpreparation of reference compounds,to co
3、nfirm the day-to-dayformulation,mixing procedure,and test methods for thereliability of testing operations used in the rubber industry,forevaluation and production control of carbon blacks in naturalthe evaluation of experimental compounds,and quality controlrubber(NR).of production compounds.1.2 Th
4、e values stated in SI units are to be regarded as the4.Standard Test Formulastandard.The values in parentheses are for information only.1.3 This standard does not purport to address all of the4.1 Standard Formula:safety concerns,if any,associated with its use.It is theNIST SRM/IRMQuantity.responsibi
5、lity of the user of this standard to establish appro-MaterialNo.4Parts by Masspriate safety and health practices and determine the applica-Natural rubber,SMR L100.00bility of regulatory limitations prior to use.Stearic acid3723.00Zinc oxideIRM 915.002.Referenced DocumentsBenzothiazyl disulfideIRM 20
6、.60Sulfur3712.502.1 ASTM Standards:Carbon black50.00D 412 Test Methods for Vulcanized Rubber and Thermo-Total161.10plastic Rubbers and Thermoplastic Elastomers-Tension2Batch factor:cTest Method AMill4.00D 1799 Practice for Carbon Black-Sampling PackagedTest Method B-Internal Mixer6.00Shipments2Test
7、Method C-Miniature Internal0.40D 1900 Practice for Carbon Black-Sampling Bulk Ship-Mixerments2D 2084 Test Method for Rubber Property-VulcanizationANIST Rubber Compounding Chemicals are available from:Office of StandardReference Materials,National Institute of Standards and Technology,Room B311,Using
8、 Oscillating Disk Cure Meter2Chemistry Bldg.,Gaithersburg,MD 20899.IRM 91 is available from R.E.Carroll,D3182 Practice for Rubber-Materials,Equipment,andInc.,1570 North Olden Ave.,Trenton,NJ 08638.IRM 2 is available from ForcovenProducts Ind.P.O.Box 1556,Humble.TX 77338.Procedures for Mixing Standar
9、d Compounds and Prepar-Use 75.00 parts by mass of carbon blacks in the N-800 and N-900 series.ing Standard Vulcanized Sheets2CWeigh rubber and carbon black to the nearest 1 g,sulfur and accelerator to theD 4483 Practice for Determining Precision for Test Methodnearest 0.02 g,and all other compoundin
10、g materials to the nearest 0.1 g.Standards in the Rubber and Carbon Black Industries25.Sampling and Sample Preparation3.Significance and Use5.1 Samples shall be taken in accordance with Practice3.1 The major portion of carbon black consumed by theD 1799 or Practice D 1900.rubber industry is used to
11、improve the physical properties,life5.2 The carbon black shall be conditioned before weighingexpectancy,and utility of rubber products.These test methodsand mixing by heating for I h in an oven set at 125+1C.Theprovide a natural rubber formulation and directions for evalu-black shall be placed in an
12、 open vessel of suitable dimensionsso that the depth of black is no more than 10 mm duringating carbon black intended for use in rubber products.3.2 These test methods may be used to characterize carbonconditioning.The black conditioned as above shall be stored inblack in terms of specific propertie
13、s of the standard compound.a closed moisture-proof container until ready for mixing.These test methods are useful for the quality assurance of6.Mixing Procedures6.1 For general mixing procedure refer to Practice D 3182.These test methods are under the jurisdiction of ASTM Committee D-24 onThe follow
14、ing mixing procedures are acceptable in testingCarbon Black and are the direct responsibility of Subcommittee D24.71 on Carboncarbon black:/Test Method A-Mill Mix,2)Test MethodBlack Testing in Rubber.Current edition approved May 10,1997.Published April 1998.OriginallyB-Internal Mixer,and 3)Test Meth
15、od C-Miniature Internalpublished as D3192-73.Last previous edition D3192-96a.Mixer.2 Annual Book of ASTM Standards,Vol 9.01.Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.D31926.2 Mill Mix-Test Method A:Duration,minAccumulativemin6.2.1 Set the mill opening at 1.4
16、mm(0.055 in.)and adjust and maintain roll temperature at 705C.006.2.2 Add rubber and band on the front roll.Make two ycuts from each side.2.02.06.2.3 Set mill opening at 1.65 mm(0.065 in.).Add stearic acid.Make one cut from each side.2.54.56.2.4 Add sulfur,accelerator,and zinc oxide.Make two y cuts
17、from each side.2.06.56.2.5 Add all the black.When that portion of the carbon black that was added has dropped through to the mill pan and thebank is dry,make two cuts from each side.Open the mill to 1.9 mm(0.075 in.)and add the carbon black from the mill panuntil all is incorporated.Make three 3 cut
18、s from each side.7.514.0Note-Do not cut any stock while free carbon black is evident in the bank or on the milling surface.Be certain to return anypigments that drop through the mill to the milling stock.6.2.6 Set the mill opening at 0.80 mm(0.032 in.)and pass the rolled batch endwise through the mi
19、ll six times.2.016.06.2.7 Open the mill to give a minimum stock thickness of 6 mm(0.25 in.)and pass the stock through the rolls four times.folding it back on itself each time.1.017.0Total Time17.06.2.8 Check the batch mass and record.If outside of the range from 641.2 to 647.6 g,reject the batch.Fro
20、m this stock,cutenough sample to allow testing of or curing characteristics in accordance with Test Method D 2084.if desired.6.2.9 Open the mill and sheet off to produce a thickness of 2.2 mm(0.085 in.).6.2.10 Cool on a flat,dry metal surface,at a temperature of 23 3C for 1 to 24 h.Unless the relati
21、ve humidity of thelaboratory is controlled at 505%,the sheeted stock should be cooled and stored in a closed container to prevent moistureabsorption.6.3 Internal Mixer-Test Method B:6.3.1 Adjust the internal mixer temperature to create in 6.3.8 a dump temperature between 110 and 125C.Close the dis-c
22、harge gate,start the rotor,raise the ram,and charge the materials as described.Lower the ram after each operation.006.3.2 Add the rubber.0.50.56.3.3 Add the benzothiazyl disulfide.0.51.06.3.4 Add the stearic acid.1.02.06.3.5 Add the zinc oxide and one-half the carbon black153.56.3.6 Add the remainde
23、r of the carbon black.1.55.06.3.7 Add the sulfur.Clean the mixer throat and the top of the ram.1.06.06.3.8 Dump at 7 min.1.070Subtotal7.06.3.9 Set the mill opening at 0.80 mm(0.032 in.)and maintain the roll temperature at 70+5C.Pass the rolled batch end-wise through the mill six times.2.09.06.3.10 O
24、pen the mill to give a minimum stock thickness of 6 mm(0.25 in.)and pass the stock through the rolls four times.folding it back on itself each time.1.010.0Total Time10.06.3.11 Check the batch mass and record.If outside of the range from 961.8 to 971.4 g,reject the batch.From this stock,cut enough sa
25、mple to allow testing of curing characteristics in accordance with Test Method D 2084,if desired.6.3.12 Open the mill and sheet off to produce a stock thickness of 2.2 mm(0.085 in.).6.3.13 Cool on a flat,dry metal surface,at a temperature of 233C for 1 to 24 h.Unless the relative humidity of thelabo
26、ratory is controlled at 50+5%,the sheeted stock should be cooled and stored in a closed container to prevent moistureabsorption.6.4 Miniature Internal Mixer-Test Method C:6.4.1 Pigment Masterbatch Preparation-Mill Mix:(Batch Factor 4.00)Set the mill opening at 1.4 mm(0.055 in.)and adjustand maintain
27、 roll temperature at705.0.00.06.4.2 Add rubber and band on the front roll.Make two 3cuts from each side2.02.06.4.3 Set mill opening at 1.65 mm(0.065 in.).Add stearic acid.Make one cut from each side.2.54.56.4.4 Add sulfur,accelerator,and zinc oxide.Make two y cuts from each side.2.06.56.4.5 Set the
28、mill opening at 0.80 mm(0.032 in.),and pass the rolled batch endwise through the mill six times.2.08.56.4.6 Check the batch mass and if outside of the range from 442.2 to 446.6 g.reject the batch.09.06.4.7 Set the mill opening to 1.5 mm(0.060 in.),band the stock.Sheet off.1.010.0Total Time10.06.4.8
29、Cool on a flat,dry metal surface,at a temperature of 23+3C.Unless the relative humidity of the laboratory is con-trolled at 50+5%,this masterbatch should be cooled and stored in a closed container to prevent moisture absorptionNote-This pigment masterbatch should be used within 6 weeks or discarded
30、and a new batch prepared.6.4.9 Carbon Black-Miniature Intema/Mixer:Mix with the head temperature of the miniature internal mixer maintained at60 3C and the unloaded slow rotor speed at 6.3 to 6.6 rad/s(60 to 63 r/min).6.4.10 Cut the pigment masterbatch prepared in 6.4.1 into strips approximately 20-
31、mm(0.75-in.)wide and weigh out 44.446.4.11 Weigh out 20.00 g of carbon black sample.6.4.12 Charge the mixing chamber with the masterbatch strips,and start the timer.0.00.06.4.13 Masticate the masterbatch.0.50.56.4.14 Add carbon black,use ram to work all of sample into chamber,sweep down orifice and
32、lower ram.1.01.56.4.15 Allow the batch to mix.1.53.0Total Time3.06.4.16 Turn off the motor,raise the ram,remove the mixing chamber and unload the batch.Record the batch temperature ifdesired.6.4.17 With the mill at room temperature,pass the batch through the mill set at 0.80 mm(0.032 in.).Fold it on
33、 itself andfeed it back through the mill five more times,always keeping the grain in the same direction and folding it on itself each time.6.4.18 Check the batch mass and record.If outside of the range from 64.12 to 64.76 g,reject the batch.6.4.19 For testing of stress-strain,pass the batch through
34、the mill to produce a stock thickness of 2.2 mm(0.085 in.).6.4.20 For testing of curing characteristics in accordance with Test Method D 2084,pass the batch through the mill to produce a minimum stock thickness of 6 mm(0.25 in.).D31926.4.21 Cool on a flat,dry metal surface,at a temperature of 23+3C
35、for 1 to 24 h.Unless the relative humidity of thelaboratory is controlled at 505%the sheeted stock should be cooled and stored in a closed container to prevent moistureabsorption7.Preparation and Testing of Vulcanizatesfrom different sample populations.Such a decision dictates that7.1 For stress-str
36、ain testing,prepare test slabs and vulcanizesome appropriate action be taken.them in accordance with Practice D 31828.3.1.2 Tensile Strength-The pooled repeatability of Test7.1.1 The recommended standard cures are 30 min at 145CMethods D 3192 Method A(using Test Methods D 412 Methodfor ASTM N-type c
37、arbon black,and 30 and 50 min at 145CA)tensile strength has been established as 1.70 MPa(246 psi).for ASTM S-type carbon black.Two single test results(or determinations)that differ by more7.1.2 Condition the cured sheets for I to 96 h at a tempera-than 1.70 MPa(246 psi)must be considered suspect,tha
38、t is,toture of233C.have come from different sample populations.Such a decision7.1.3 Prepare test specimens in accordance with Practicedictates that some appropriate action be taken.D 3182 and obtain tensile stress at 300%elongation,tensile8.3.1.3 Ultimate Elongation-The pooled repeatability ofstreng
39、th,and ultimate elongation parameters in accordanceTest Methods D 3192 Method A(using Test Methods D 412with Test Methods D 412.Method A)ultimate elongation has been established as 28.2%7.2 For measuring vulcanization parameters by the cureme-Two single test results(or determinations)that differ by
40、moreter in accordance with Test Method D 2084,use the 6-mmthan 28.2 must be considered suspect,that is,to have come(0.25-in.)thickness samples that were previously prepared.from different sample populations.Such a decision dictates that7.2.1 The recommended standard test conditions are 1.7 Hzsome ap
41、propriate action be taken.(100 cpm)oscillation frequency,1 0.03 amplitude of8.3.2 Reproducibility:oscillation,and 160+0.3C die temperature using the micro8.3.2.1 Tensile Stress at 300 Elongation-The pooleddie system.reproducibility of Test Methods D 3192 Method A(using Test7.2.2 The recommended stan
42、dard test parameters are M,Methods D412 Method A)tensile stress at 300 elongationM.ts,t(50)and t(90).has been established as 1.09 MPa(158 psi).Two single testresults(or determinations)produced in separate laboratories8.Precision and Bias 3that differ by more than 1.09 MPa(158 psi)must be considered8
43、.1 This precision and bias statement has been prepared insuspect,that is,that they represent different sample popula-accordance with Practice D 4483.Refer to Practice D 4483 fortions.Such a decision dictates that appropriate investigative orterminology and other statistical details.technical or comm
44、ercial actions,or both,be taken.8.2 Precision-The precision results in this precision and8.3.2.2 Tensile Strength-The pooled reproducibility ofbias section give an estimate of the precision of this testTest Methods D 3192 Method A(using Test Methods D 412method with the materials(rubbers,carbon blac
45、ks,etc.used inMethod A)tensile strength has been established as 2.07 MPathe particular interlaboratory program described in 8.3 through(300 psi).Two single test results(or determinations)produced8.5.2.3.The precision parameters should not be used forin separate laboratories that differ by more than
46、2.07 MPa(300acceptance or rejection testing of any group of materialspsi)must be considered suspect,that is,that they representwithout documentation that they are applicable to those par-different sample populations.Such a decision dictates thatticular materials and the specific testing protocols of
47、 the testappropriate investigative or technical or commercial actions,ormethod.both,be taken.8.3 Mill Mix-Test Method A-A Type 2 interlaboratory8.3.2.3 Ultimate Elongation-The pooled reproducibility ofprecision program was conducted in 1990.Both repeatabilityTest Methods D3192 Method A(using Test Me
48、thods D 412and reproducibility represent short-term testing conditionsMethod A)ultimate elongation has been established as 42.4%Nine laboratories tested four carbon blacks(SRBs A-4,B-4,Two single test results(or determinations)produced in separateD-4,and F-4)once on each of two different days.Test r
49、esultslaboratories that differ by more than 42.4%must be consideredwere obtained in accordance with Test Method D 412 and aresuspect,that is,that they represent different sample popula-expressed as differences from IRB 6.A test result is the valuetions.Such a decision dictates that appropriate inves
50、tigative orobtained from a single determination.Acceptable differencetechnical or commercial actions,or both,be taken.values were not measured(see Table 1).8.4 Internal Mixer-Test Method B-A Type 2 interlabora-8.3.1 Repeatability:tory precision program was conducted in 1990.Both repeat-8.3.1.1 Tensi
51、le Stress at 300 Elongation-The pooledrepeatability of Test Methods D3192 Method A(using Testability and reproducibility represent short-term testing condi-Methods D412 Method A)tensile stress at 300 elongationtions.Four laboratories tested four carbon blacks(SRBs A-4,B-4,D-4,and F-4)once on each of
52、 two different days.Testhas been established as 1.01 MPa(146 psi).Two single testresults were obtained in accordance with Test Method D 412results(or determinations)that differ by more than 1.01 MPaand are expressed as differences from IRB 6.A test result is the(146 psi)must be considered suspect,th
53、at is,to have comevalue obtained from a single determination.Acceptable differ-ence values were not measured(see Table 2).Supporting data for this precision evaluation are available from ASTM8.4.1 Repeatability:Headquarters.Request RR:D24-1031.8.4.1.1 Tensile Stress at 300 Elongation-The pooledD3192
54、TABLE 1 Test Methods D3192 Test Method Precision-Type 2(Mill Mix-Method A(Using Test Methods D 412 Method A)Tensile Stress at 300%Elongation,MPa(psi)Within LaboratoriesBetween LaboratorieseMaterialMean LevelSSRRD-4-2.79(-404)0.40(58)1.13(164)0.40(58)1.13(164)A-4-0.63(-92)0.38(55)1.07(155)0.41(59)1.1
55、5(166)B-4-0.28(-40)0.29(43)0.83(120)0.39(56)1.10(159)F-43.23(468)0.34(50)0.97(141)0.35(50)0.98(142)Average-0.08(-12)Pooled values0.36(52)1.01(146)0.39(56)1.09(158)Tensile Strength,MPa(psi)Within LaboratoriesBetween LaboratoriesMaterialMean LevelSrSRRD-4-2.08(-301)0.67(97)1.88(273)0.67(97)1.88(273)F-
56、4-2.01(-292)0.79(114)2.23(323)0.99(143)2.79(405)B-4-0.21(-31)0.33(48)0.93(135)0.65(95)1.85(268)A-42.93(424)0.52(75)1.47(213)0.54(78)1.53(221)Average-0.34(-49)Pooled values0.60(87)1.70(246)0.73(106)2.07(300)Ultimate Elongation.%Within LaboratoriesBetween LaboratorieseMaterialMean LevelSrSRRF-4-948.22
57、3.314.541.1B-411.432.214.340.5D-42112.134.312.836.3A-4347.220.417.850.5Average-9Pooled values10.028.215.042.4This is short-term precision(days)with outliers removed from the data set.BSymbols are defined as follows:S,=within-laboratory standard deviation.r=repeatability(in measurement units).S=stand
58、ard deviation for total between-laboratory variability,andR=reproducibility(in measurement units).repeatability of Test Methods D 3192 Method B(using Testthat differ by more than 1.37 MPa(198 psi)must be consideredMethods D 412 Method A)tensile stress at 300%elongationsuspect,that is,that they repre
59、sent different sample popula-has been established as 0.68 MPa(99 psi).Two single testtions.Such a decision dictates that appropriate investigative orresults(or determinations)that differ by more than 0.68 MPatechnical or commercial actions,or both,be taken.(99 psi)must be considered suspect,that is,
60、to have come from8.4.2.2 Tensile Strength-The pooled reproducibility ofdifferent sample populations.Such a decision dictates thatTest Methods D 3192 Method B(using Test Methods D 412some appropriate action be taken.Method A)tensile strength has been established as 1.67 MPa8.4.1.2 Tensile Strength-Th
61、e pooled repeatability of Test(242 psi).Two single test results(or determinations)producedMethods D 3192 Method B(using Test Methods D 412in separate laboratories that differ by more than 1.67 MPa(242Method A)tensile strength has been established as 0.88 MPapsi)must be considered suspect,that is,tha
62、t they represent(128 psi).Two single test results(or determinations)that differdifferent sample populations.Such a decision dictates thatby more than 0.88 MPa(128 psi)must be considered suspect.appropriate investigative or technical or commercial actions,orthat is,to have come from different sample
63、populations.Suchboth,be taken.a decision dictates that some appropriate action be taken.8.4.2.3 Ultimate Elongation-The pooled reproducibility of8.4.1.3 Ultimate Elongation-The pooled repeatability ofTest Methods D 3192 Method B(using Test Methods D 412Test Methods D 3192 Method B(using Test Methods
64、 D 412Method A)ultimate elongation has been established as 45.9%.Method A)ultimate elongation has been established as 34.1%Two single test results(or determinations)produced in separateTwo single test results(or determinations)that differ by morelaboratories that differ by more than 45.9%must be con
65、sideredthan 34.1%must be considered suspect,that is,to have comesuspect,that is,that they represent different sample popula-from different sample populations.Such a decision dictates thattions.Such a decision dictates that appropriate investigative orsome appropriate action be taken.technical or com
66、mercial actions,or both,be taken.8.4.2 Reproducibility:8.5 Miniature Internal Mixer-Test Method C-A Type 28.4.2.1 Tensile Stress at 300%Elongation-The pooledinterlaboratory precision program was conducted in 1990.Bothreproducibility of Test Methods D 3192 Method B(using Testrepeatability and reprodu
67、cibility represent short-term testingMethods D 412 Method A)tensile stress at 300%elongationconditions.Two laboratories tested four carbon blacks(SRBshas been established as 1.37 MPa(198 psi).Two single testA-4,B-4,D-4,and F-4)once on each of two different days.results(or determinations)produced in
68、separate laboratoriesTest results were obtained in accordance with Test Method4D3192TABLE 2 Test Methods D 3192 Test Method Precision-Type 2(Internal Mixer-Method B(Using Test Methods D 412 Method A)Tensile Stress at 300%Elongation,MPa(psi)Within LaboratoriesBetween LaboratorieseMaterialMean LevelSS
69、RRD-4-2.72(-395)0.16(23)0.45(65)0.34(49)0.95(138)A-4-0.64(-92)0.25(36)0.71(103)0.67(98)1.91(277)B-4-0.53(-76)0.15(21)0.42(61)0.49(71)1.39(201)F-42.95(428)0.35(51)1.00(145)0.35(51)1.00(145)Average-0.24(-34)Pooled values0.24(35)0.68(99)0.48(70)1.37(198)Tensile Strength,MPa(psi)Within LaboratoriesBetwe
70、en LaboratoriesMaterialMean LevelSrSRRF-4-2.69(-390)0.22(32)0.62(90)0.81(118)2.30(334)D-4-1.75(-254)0.52(75)1.46(212)0.52(75)1.46(212)B-4-0.32(-47)0.08(12)0.24(34)0.45(65)1.28(185)A-42.43(353)0.26(37)0.72(105)0.51(74)1.44(209)Average-0.58(-84)Pooled values0.31(45)0.88(128)0.59(86)1.67(242)Ultimate E
71、longation,%Within LaboratoriesBetween LaboratorieseMaterialMean LevelSrSRRF-4-10014.340.515.243.0B-414.211.810.630.0D-4138.524.18.524.1A-41616.947.825.271.4Average-13Pooled values12.034.116.2045.9This is short-term precision(days)with outliers removed from the data set.Symbols are defined as follows
72、:S.=within-laboratory standard deviation,r=repeatability(in measurement units).S=standard deviation for total between-laboratory variability,andR=reproducibility(in measurement units).D412 and are expressed as differences from IRB 6.A test8.5.2 Reproducibility:result is the value obtained from a sin
73、gle determination.8.5.2.1 Tensile Stress at 300%Elongation-The pooledAcceptable difference values were not measured(see Table 3).reproducibility of Test Methods D 3192 Method C(using Test8.5.1 Repeatability:Methods D 412 Method A)tensile stress at 300%elongation8.5.1.1 Tensile Stress at 300%Elongati
74、on-The pooledhas been established as 1.07 MPa(156 psi).Two single testrepeatability of Test Methods D 3192 Method C(using Testresults(or determinations)produced in separate laboratoriesMethods D 412 Method A)tensile stress at 300%elongationthat differ by more than 1.07 MPa(156 psi)must be considered
75、has been established as 0.64 MPa(93 psi).Two single testsuspect,that is,that they represent different sample popula-results(or determinations)that differ by more than 0.64 MPations.Such a decision dictates that appropriate investigative or(93 psi)must be considered suspect,that is,to have come fromt
76、echnical or commercial actions,or both,be taken.different sample populations.Such a decision dictates that8.5.2.2 Tensile Strength-The pooled reproducibility ofsome appropriate action be taken.Test Methods D 3192 Method C(using Test Methods D 4128.5.1.2 Tensile Strength-The pooled repeatability of T
77、estMethod A)tensile strength has been established as 3.02 MPaMethods D 3192 Method C(using Test Methods D 412(438 psi).Two single test results(or determinations)producedMethod A)tensile strength has been established as 0.62 MPain separate laboratories that differ by more than 3.02 MPa(438(90 psi).Tw
78、o single test results(or determinations)that differpsi)must be considered suspect,that is,that they representby more than 0.62 MPa(90 psi)must be considered suspectdifferent sample populations.Such a decision dictates thatthat is,to have come from different sample populations.Suchappropriate investi
79、gative or technical or commercial actions,ora decision dictates that some appropriate action be taken.both,be taken.8.5.1.3 Ultimate Elongation-The pooled repeatability of8.5.2.3 Ultimate Elongation-The pooled reproducibility ofTest Methods D 3192 Method C(using Test Methods D 412Test Methods D 3192
80、 Method C(using Test Methods D 412Method A)ultimate elongation has been established as 28.7%Method A)ultimate elongation has been established as 86.4%.Two single test results(or determinations)that differ by moreTwo single test results(or determinations)produced in separatethan 28.7%must be consider
81、ed suspect,that is,to have comelaboratories that differ by more than 86.4%must be consideredfrom different sample populations.Such a decision dictates thatsuspect,that is,that they represent different sample popula-some appropriate action be taken.tions.Such a decision dictates that appropriate investigative or5
