Table Of Contentइंटरनेट मानक
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Whereas the Parliament of India has set out to provide a practical regime of right to
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in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
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“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 6918 (2002): Mercaptobenzothiazole [PCD 13: Rubber and
Rubber Products]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
IS 6918:2002
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Indian Standard
MERCAPTOBENZOTHIAZOLE — SPECIFICATION
(First Revision )
ICS 83.040.01
0 BIS2002
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
April 2002 Price Group 7
Rubber Products Sectional Committee, PCD 13
FOREWORD
This Indian Standard (First Revision) wasadopted bythe Bureau of Indian Standards, after the draft finalized by
the Rubber Products Sectional Committee hadbeen approved bythePetroleum, CoalandRelated Products Division
Council.
Mercaptobenzothiazole isasemiultra nonstaining accelerator usedincompounding ofrubber.Mercaptobenzothiazole
is soluble in acetone, ethyl alcohol, chloroform and dilute alkalis, partially soluble in benzene and insoluble in
water and gasoline. Since itimparts bitter taste tothe vulcanizate, mercaptobenzothiazole should not be used for
those rubber parts which come in contact with the food products. Besides specifying chemical requirements, the
standard includes a recommended procedure for evaluating the material by means of a standard compounding
and vulcanizing procedure.
This standard was published in 1972. Inthis version ( first revision ) requirements for melting point and assay
have been increased. Residue on63micron and surface coating for coated grade have been added. Requirement
for loss on heating, sulphated ash and manganese have been tightened.
The composition ofthe Committee responsible for formulation ofthis standard isgiven inAnnex M.
For the purpose of deciding whether aparticular requirement ofthis standard iscomplied with, the final value,
observed or calculated, expressing the result of a test of analysis, shall be rounded off in accordance with
1S2:1960 ‘Rules forrounding offnumerical values (revised)’. Thenumber of significant places retained inthe
rounded off value should be the same as that of the specified value in this standard.
.,
&
IS 6918:2002
Indian Standard
MERCAPTOBENZOTHIAZOLE — SPECIFICATION
(First Revision )
1 SCOPE grade andpelletformfreefromanyvisible impurities.
This standard prescribes the requirements, methods
3.2 Chemical Requirements
of sampling and test for mercaptobenzothiazole
intended for use as an accelerator in rubber Thematerialshallcomplywiththechemicalrequirements
compounds. given inTable 1when tested according tothe quality
of water and chemicals as given inAnnex A.
2 REFERENCES
ThefollowingIndianStandardscontainprovisionwhich 3.3 Performance Requirement
through reference in this text, constitute provisions
ofthisstandard. Atthetimeofpublication, theeditions The material when compounded and tested asgiven
indicated were valid. All standards are subject to inAnnexKshallhave itspropertiescomparable,within
revision, and parties to agreements based on the thelimitsprescribed inK-4.1, withthoseofthesample
standard are encouraged to investigate thepossibility complying with the requirements of3.1 and 3.2 and
ofapplying the most recent editions ofthe standards approved previously by the purchaser.
indicated below:
4 PACKING AND MARKING
IS No. Title
4.1 Packing
1070:1992 Reagent grade water (third
revision )
Thematerial shallnormally bepacked in20or 25kg
1675:1971 Stearic acid, technical (first packs ofmultiwallpaperbagsorasagreed to between
revision ) the purchaser and the supplier. The material
should accompany with Materials Supply Data
1683:1994 Barytes forrubber industry (second
Sheet (MSDS ).
revision )
3399:1993 Zinc oxide for rubber industry 4.2 Marking
(second revision)
The packages shall be securely closed and legibly
3400 Methods of test for vulcanized marked withthefollowing information:
rubbers:
a) Name ofthematerial,
(Part 1): 1987 Tensile stress — Strain properties
(second revision ) b) Indication of source of manufacture,
(Part 2):1995 Hardness (second revision )
c) Net massofthe material,
3660 Methods oftest for natural rubber:
d) Lot/Batch reference number, and
(Part 7): 1989 Determination ofMooney viscosity
(NR :8 )(second revision ) e) Handling and storage precautions (ifany ).
(Part 8): 2000 Mixing andvulcanizing ofrubber in
standard compound (NR: 9) 4.2.1 BIS Certification Marking
(second revision)
The packages mayalso bemarked with the Standard
4588:1988 Rubber, raw, natural (third Mark.
revision )
4.2.1.1 The use of the Standard Mark is governed
7086(Part 1): Method of sampling and test for
bythe provisions oftheBureau ofZndian Standards
1973 rubber compounding ingredients
Act, 1986 and the Rules and Regulations made
3 REQUIREMENTS thereunder. The details of conditions under which
thelicencefortheuseofStandardMarkmaybe granted
3.1 Description
tomanufacturers or producers maybe obtained from
The material shall be inpowder — noncoatedorcoated the Bureau of Indian Standards.
1
IS 6918:2002
Table 1 Chemical Requirements ofMercaptobenzothiazole (MBT )
(Clause 3.2)
S1No. Characteristic Requirement MethodofTest,
Ref to Annex
(1) (2) (3) (4)
O Assay ( MBT content ),percent bymass, Min: B
a)Powder—noncoated grade 98.0
b)Powder—coated grade 96.0
c) Pellet 96.0
ii) Melting point, “C: c
a) Appearance of first droplet, &fin I70
b) Completion of melting 176-184
iii) Residue on 150micron ISSieve,percent bymass, 0.05 D
Max ( forpowders only )
iv) Residue on63 micron 1SSieve,percent bymass, 0.75 D
Max (for powders only)
v) Loss on heating for 2 h at 105”C,percent by 0.40 E
mass,Max
vi) Sulphated ash, percent bymass, Max 0.4 F
vii) Copper content, ppm, Max 20 G
viii) Manganese content, ppm, Max 40 H
ix) Surface coating ( for coated grade only )percent 2.2 J
bymass, Max
5 SAMPLING conducted on individual sample.
5.1 The representative samples ofthe material shall
be drawn asprescribed inAnnex L.
5.2 Number ofTests 5.2.2 Testforallothercharacteristicsshallbeconducted
on acomposite sample.
5.2.1 Test for copper content (see Table 1)shall be
ANNEX A
( Clause 3.2)
MERCAPTOBENZOTHIAZOLE (MBT )
A-1 QUALITY OF REAGENTS NOTE— ‘Pure chemicals’ shall mean chemicals that
do not contain impurities which affect the results of
Unless specifiedotherwise,purechemicalsanddistilled test or analysis.
water (see IS 1070 )shall beemployed intests.
IS 6918:2002
ANNEX B
[ Table 1, S1No. (i) ]
DETERMINATION OF ASSAY (MBT CONTENT )
B-1 GENERAL B-4 PROCEDURE
For routine work the method given below may be Weightothenearest 0.1mg,0.50+ 0.05 gofthe well
followed while for more accurate work methods mixed sample and transfer to a 500-ml dry conical
based onHigh Performance Liquid Chromatography flask (in case of pelleted products, crush a50gof
described inother overseas standards (for example representative sample, mix well and use
ASTM D5297-95) can beused. 0.50 + 0.05 g for the test ). Add 50-ml chloroform
solvent and dissolve the sample. Add 200 mlwater
B-2 ROUTINE METHOD and25-mlbuffersolutionpH 4.95.Add0.5-mlofstarch
indicator solution andtitrate against 0.10 Nstandard
This method determines mercaptobenzothiazole
iodine solution shaking the flask vigorously during
(MBT)asamajorconstituent incommercialproducts,
the titration until apermanent blue colour appears.
in solutions or in blends that do not contain other
Carryoutablankofrepeating steps2to4intheabsence
constituents capable of reacting with iodine.
ofthe sample.
B-3 REAGENTS
B-5 CALCULATION
B-3.1 Chloroform, LR Grade Assay ( MBT content),
B-3.2 Buffer Solution, pH 4.95 (V1-VZ)XI.672
percent by mass =
M
Dissolve 280 g of anhydrous sodium acetate and
280g(267-ml)ofglacialaceticacidinwateranddilute where
to 1000-ml.
v, = mlof 0.1 N iodine solution used by the
B-3.3 Iodine sample;
V*= ml of 0.1 N iodine solution used for the
0.10 N, standard volumetric solution.
blank titration; and
B-3.4 Starch Indicator Solution (freshlyprepared) M. mass of the sample taken ing.
ANNEX C
[Table 1,S1No. (ii)]
DETERMINATION OF MELTING POINT
C-1 GENERAL METHOD itwascalibrated.
Essentially it isacapillary tube method, though the C-1.1.3 Heating Medium
medium for heating can be the traditional liquid
Theliquidbathapparatus isshowninFig. 1. Itconsists
with astirrer or asolid metal block, heated bygasor
ofa500-ml borosilicateglassbeaker(tallform) closed
electricity.
withachloroprene rubber bungthrough which passes
C-1.1 Apparatus a central outer glass tube. The outer tube is fitted
withachloroprene rubber bungandastirrer onashaft
C-1.1.1 Melting Point Tubes
passing through inner tube. Outer tube has aring of
Glass capillary tubes approximately 10cmlongwith fourholesblowninittoallowcirculationofthe heating
wallthickness 0,1 to 0.15 mm,and internal diameter liquid. The chloroprene rubber bung isbored with a
0.1 to 1,1mm, closed atone end. holetoholdthethermometer andsmallholesoneither
sideofthis forthe meltingpointtubes. Ametalscreen
C-1.1.2 Thermometer
is necessary to protect the apparatus from drought.
The thermometer shall be calibrated and graduated The heat transfer fluid should be such that it is not
in 1“C divisions. During the determination the volatile below 300°C, is colorless at working
thermometer shall be immersed tothedepth atwhich temperatures, non-flammable anddoes not attack the
3
IS6918:2002
C-2 REFEREE METHOD
C-2.1 Apparatus
C-2.1.1 Heating Bath and Screen
Around-bottomed 150-ml heat-resistant glass flask
havinga neckabout 100mmlongand50mmdiameter
filled with pure concentrated sulphuric acid (or any
SECTIONXX
/’”- ‘“BE other suitable liquid, such as glycerine or paraffin
oil)toaboutthree-fourths ofits capacity. Atesttube
about150mmlongandofsuchdiameterastofitloosely
inthe neck ofthe flask isplaced inposition by glass
THERMOMETER beads fused on it near the top so that the bottom of
,---RUBBER thetubeisabout 12.5mmfromthebottom oftheflask.
BUNG This tube isalso filled with the same liquid, the level
ofwhichshouldbeslightlylowerthanthatoftheliquid
FOUR HOLES
inthe flask. The tube is closed by a cork carrying ‘a
L .1 thermometer and provided with a slit on one side to
allowthehotairtoescape. Ametalscreenis necessary
x x to protect the flame and heating bath from draught.
GIASS Asuitable screen ismade from sheet iron bent twice
/-’-’-
BEAKER at right angles, having aheight of about 45 cm with
sides and back about 20 cm in width and the front
open. Atadistance of20cmfrom thebottom there is
a edge 12.5 mm side on the inside. A sheet of iron
withacentral hole38 mmindiameter isplaced onthe
edge and a sheet of asbestos with a central hole
FIG. 1 APPARATUS FORDETERMINATIONOFMELTING POINT
38mmindiameterisplacedonthetopoftheironsheet.
rubber bung. Asilicon oilofsuitable low viscosity Atthebackofthescreen,immediately behindtheflask
is suggested. Alternatively anelectrically (or gas) when in position, there is ahole 38 mm in diameter
heated metal block may beusedastheheatingmedium. behind which asuitable source of illumination (say,
It is important that the rate of heating of the block electric lamp)isplaced. .-A-
--.
shall bereadily controlled.
C-2.1.2 MeltingPoint Tubes
C-1.2 Procedure
Readymade tubes ( 100mm long and approximately
Transfer asmall quantity ofthefinely ground sample 1.5mmexternal diameter) arerecommended. These
toeach ofthe capillary tube and cause ittofalltothe shall be sealed at both the ends as soon as they are
cIosed end by tapping on the bench. The quantity taken out from the package. Just before use, break
usedshould fill2.5to 3.5mmdepth ofthetube when off one end.
compacted. Heat the block ( or bath with the stirrer
C-2.1.3 Thermometer
incontinuous operation )rapidly to20to25°C below
the lower end ofthe expected melting range andthen Thethermometer usedshallbestandardized covering
adjust therate ofheating sothatthetemperature rises the approximate range, and graduated in 0.1“C
uniformly at a rate of 1OC/min. When the divisions. The bulb of the thermometer should be
temperature isabout 12°Cbelow the lowerendofthe about6.35mmlongand4.8mmindiameter. Immerse
specified melting range, the capillaries are inserted the thermometer to the depth at which it has been
intothe holes inthe metal block (orinserted through standardized.
the small holes in bung B and held at the desired
C-2.2 Procedure
immersionlevelbystickingasmallpaperflagKaround
each one ). C-2.2. 1 Preparationof TestSample
C-1.3 Report Itisessentialtoensurethatahighdegree ofuniformity
of the sample is attained on account of very small
Continuously observe the sample asthe temperature
amount of material taken for the test. Prepare the
rises and record the temperatures when there is:
sample asfollows:
a) the first appearance ofdrops orameniscus,
Grind2to5gofthewell-mixed sampleinasmall,
and
clean, dry glazed porcelain or glass mortar, then
b) complete melting.
grind finely aportion of this inan agate mortar.
IS 6918:2002
C-2.2.2 Transfer a small quantity of the prepared sealed end of the capillary tube must be on a level
materialtoacapillary tube,andcausetheportiontaken with the bottom of the bulb of the thermometer.
to fall to the sealed end by tapping on the bench. Carefully replace thethermometer with the adhering
Assemble the apparatus withthethermometer insuch capillary tube in the inner tube. Ifthis operation has
a way that the bottom of the bulb is not less than been carried out quickly, the material under test shall
6.35 mm from the bottom of the test tube. Heat the be introduced into the heating bath (thetemperature
bath rapidly toafewdegreesabovetheexpectedmelting of which is rising uniformly at the rate of
point, allowthetemperature tofallgradually toabout 10C/min ) when the bath temperature is about
15°Cbelow the expected melting point, then adjust 10°Cbelow the expected melting point.
the rate of heating so that the temperature rises
C-2.3 Report
uniformlyattherateof 10C/min.Whenthetemperature
is about 12°C below the expected melting point, Record the temperature when thc;e is:
withdraw the thermometer and quickly attach the
a) thefirstappearance ofdrops orofameniscus,
capillary tube to it,either bymeans of athin rubber
and
ring (cut from the end ofanarrow rubber tubing )or
bycausing itto adhere by capillary attraction. The b) complete melting.
ANNEX D
[Table 1,S1No. (iii) and(iv)]
RESIDUE ON (63 micron/150 micron) SIEVE
D-1 APPARATUS adjust the height ofthe central jet sothat the level of
water inthefunnel commences tofall.When thelevel
D-1.l Gailie-Porriti Sieve
hasfallenwithin50mmofthesieve,turnonsubsidiary
The apparatus (see Fig.2)consists ofametal funnel supply untilthe level iswithin COmm from thetop of
terminating at the foot inashort cylindrical outlet, the funnel and maintain there until the liquid appears
inwhich isinserted ashallow removable cup. Tothe clear and continue supply then for a further period
bottom ofthe cup, awire gauge (conforming to 63/ of 1min. Turn off the subsidiary supply and allow
150micron ISSieve) of25 mmdiameter issoldered. the leveltofall again. When funnel isempty, turn off
Waterunderpressure of 1.5to3.5 kgf/cm2is supplied the mainjet and allow todrain. Remove the cup and
by atube fitted with a nozzle desig n ed to discharge examine for any large soft agglomerates. Ifpresent,
aspreading jet throughout the wire gauze. The tube break up gently with the finger and replace the cup
isalso so arranged that the distance ofthe orifice in and wash with water from the subsidiary supply for
relation to the wire gauze can be adjusted. The tube 2min. Transfer thegrit onthe sieveto awatch glass,
isprovided withafilter toensure removal ofanysolid dryto 100”Candweigh. Theaboveoperation iscarried
particles from thewater. Asecond tubewhich isalso outwithremovable cupsprovided with63/150micron
provided withafilter isimprovised tosupply agentle provided with IS Sieve and 300 micron IS sieve and
stream of water for wetting the powder and for the grit onthe sieve isdried and weighed, each time
supplying morewatertothefunnelduringtheprogress separately.
oftest. The areaofthewiregauzeshallbesufficiently
D-2.2 Powders which are very light, are difficult to
large to prevent undue loss of pressure head in the
wetat onetime inaslargequantityas50g. Tofacilitate
case of first tube.
wetting of these powders, either a small amount of
D-2 PROCEDURE wetting agent may be added or the material should
be added in small quantities into the apparatus.
D-2.1 Weighaccurately about50+ 1gofthematerial.
Fill half ofthe funnel with water from the subsidiary D-3 CALCULATION
supply, then bring the central jet ( see Fig. 2 ) into
operation. Transfer theweighed meterial tothemetal Express the mass of residue as percentage of the
funnel inthe form of aslurry with asuitable wetting material taken for the test and the IS Sieve used for
agent.Turnoffthe subsidiary supplyand,ifnecessary, the test.
5
