IS 10016-6: Methods of Test for Polybutadiene Rubbers, Part 6: Evaluation of Vulcanization Characteristics of Polybutadiene Rubbers (BR : 2)

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IS 10016-6 (2000) : Methods of Test for Polybutadiene
Rubbers, Part 6: Evaluation of Vulcanization
Characteristics of Polybutadiene Rubbers (BR : 2) [PCD 13:
Rubber and Rubber Products]

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IS 10016 (Part 6) : 2000

Indian Standard
METHOD-SOFTESTFORPOLYBUTADIENERUBBERS

PART 6 EVALUATION OF VULCANIZATION CHARACTERISTICS OF
POLYBUTADIENE RUBBERS (BR : 2)

ICS 83.060

©BIS 2000

BUREAU OF INDIAN STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

May 2000 Price Group 2

Rubber Sectional Committee, PCD 14

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Rubber
Sectional Committee had been approved by the Petroleum, Coal and Related Products Division Council.

In this series methods of test for polybutadiene rubbers are given. Various other methods of test for
polybutadiene rubbers are covered in following parts:

Parti Method of taking out test portions from sample bales

Part 2 Determination of ash

Part 4 Determination of CIS, Trans and Vinyl structure

Part5 Determination of gel content

The committee has decided to prepare common methods of test for synthetic rubber under SR (synthetic tubber)
series and will be applicable to all types of synthetic rubbers being produced indigenously. After preparation of
common methods of test, Part 1 , Part 2 and Part 5 would be withdrawn.

In preparation of this standard assistance has been drawn from ISO 2476 : 1996 'Rubber, butadiene (BR) —
Solution-polymerized types — Evaluation procedure' published by International Organization for
Standardization (ISO) and ASTM D 3189 Rubber-Evaluation Solution BR (Polybutadiene Rubber),
published by American Standards for Testing and Materials.

In reporting the result of a test or analysis made in accordance with this standard, if the final value, observed or
calculated, is to be rounded off, it shall be done in accordance with IS 2 : 1960 'Rules for rounding off
numerical values (revised)'.

IS 10016 (Part 6): 2000

Indian Standard
METHODSOFTESTFORPOLYBUTADIENERUBBERS

PART 6 EVALUATION OF VULCANIZATION CHARACTERISTICS OF
POLYBUTADIENE RUBBERS (BR : 2)

1 SCOPE

This standard prescribes standard materials,
equipment and processing methods for evaluating
vulcanization characteristics of solution-polymerized
butadiene rubbers (BR), including oil-extended types
(OEBR).

2 NORMATIVE REFERENCES

The following standards contain provisions which
through reference in this text, constitute provisions of
this standard. At the time of publication the editions
indicated were valid. All standards are subject to
revision, and parties to agreements based on this
standard are encouraged to investigate the possibility
of applying the most recent editions of the standards
indicated below:

Title
Stearic acid, technical (first
revision)

Methods of test for vulcanized
rubbers: Part 1 Tensile stress-strain
properties (second revision)
Zinc oxide for rubber industry
(second revision)
Methods of test for natural rubber:
Determination of ash (NR:3)
(second revision)

Determination of total copper
(NR:4) (second revision)
Determination of manganese
(NR:5) (second revision)
Determination of rubber hydro-
carbon (NR:7) (second revision)
Determination of Mooney viscosity
(NR: 8)

Mixing and vulcanizing of rubber
in standard compound (second
revision)

Rubber — Raw, natural and
synthetic — Methods for sampling
and sample preparation (first
revision)

Benzothiazyi-2-cyclohexyl sulphe-
namide (first revision)
High abrasion furnace (HAP)
carbon black (first revision)
Sulphur for rubber industry (first
revision)

11720

IS No.
1675: 1971

3400 (Part 1) :

1987

3399 : 1993

3660
(Part 3) :

1988

(Part 4) :

1988

(Part 5) :

1988

(Part 6) :

1988

(Part 7) :

1988

(Part 8) :

1999

5599 : 1999

7069 : 1986
7497 : 1985
8851 : 1994

(Part 2)

(Part 3)
(Part 4)
13867 : 1993

Methods of test for synthetic

rubber:
1989 Measurement of vulcanization

characteristics with oscillating disc

curemeter (SR:2)
1993 Determination of Mooney viscosity
1993 Determination of volatile matter

Rubber standard temperature,

humidities and times for the

conditioning and testing of test

pieces

3 TEST RECIPE FOR EVALUATION OF
VULCANIZATION CHARACTERISTICS

3.1 Standard Test Formula

The standard test formula is given below:

SI Material
No.

Parts b)

> Mass

Non-oil
Extended

Oil
Extended

i) Butadiene rubber (BR)

100.00

100.00

ii) Zinc oxide (see IS 3399)

3.00

3.00

iii) Oil furnace black (HAP)"

(No. 330) (see IS 7497)

60.00

60.00

iv) Stearic acid (see IS 1675)

2.00

2.00

v) Petroleum oil
(naphthenic) 2 ' (see
ASTM Type 103)

15.00

vi) Sulphur (see IS 885 1)

1.50

1.50

vii) CBS (see IS 7069) or
TBBS 3) (for method D)
(min)

0.90

0.90

viii) Calculated density,
mg/m 3

1.11

1.14 to
1.16 4)

l> The current Industry Reference Black may be used in place
of HAF carbon black but this may give slightly different
results.

2) ASTM Type 103 oil has the following characteristics:

Kinematic viscosity at 100°C, 16.8 ± 1.2 mm 2 /s

Viscosity gravity constant, 0.889 ± 0.002

The Viscosity Gravity Constant (VGC) is calculated from
the Say bolt Universal viscosity at 37.8°C and the relative
density at 15.5/15.5°C. Use the following equation to
calculate the VGC from the measured properties:

IS 10016 (Part 6) : 2000

VGC-

10rf-1.07521og 10 (v-38)

10»log l0 (v-38)
where

d = relative density at 15.5/15.5°C;

v = Saybolt Universal Viscosity at 7.8°C.

3) N-ter-butyl-2-benzothiaziIe sulphenamide as per Material
Reference No. 384.

4> Based on 37.5 percent oil-extended BR.

3.2 Procedure

3.2.1 Equipment and Procedure

Equipment and procedure for the preparation, mixing
and vulcanization shall be in accordance with
different parts of IS 3660 (Part 8) wherever
applicable.

NOTE — Details of a suitable internal mixer are given in
Annex A.

3.2.2 Mixing Procedure

The following four mixing procedures are specified:

M ethod A Internal mixer for initial and final
mixing;

M ethod B Internal mixer for initial and mill
for final mixing;

M ethod C Mill mixing; and

Method D Miniature internal mixing.

NOTE — These procedures may give different results.

The mill handling of solution butadiene rubbers is more
difficult than for other rubbers and mixing is best accomplished
by using an internal mixer. Because of the difficulty of mill
mixing butadiene rubber, it is recommended that one of the
internal mixer procedures (methods A, B or D) be used where
such equipment is available. With some types of butadiene
rubber it is not possible to get a satisfactory mix using the mill
mixing procedure.

3.2.2.1 Method A

Internal Mixer for initial and final mixing
Stage 1 — Initial mixing procedure

Duration Cumu-

(min) lative
(min)

a) Adjust the temperature, speed
and ram pressure of the internal

mixer to achieve the condition
outlined in 3.2.2.1(e). Close the
discharge gate, start the rotor
and raise the ram.

b) Charge one-half of the tubber, the 0.5 0.5
zinc oxide, the carbon black, the oil

(omit from Formula 2 for OEBR),
the stearic acid and the balance of
the rubber. Lower the ram.

Duration Cumu-

(min) lative

(min)

c) Allow the batch to mix. 3.0 3.5

d) Raise the ram and clean the 0.5 4.0
mixer throat and the top of the

ram. Lower the ram.

e) Discharge the batch at a 2.0 6.0
temperature of 170°C or after a

total time of 6 min, whichever
occurs first.

f) Immediately pass the batch three times through a
laboratory mill with a mill opening of 5.0 mm
and a temperature of 50 ± 5°C. Check, weigh the
batch. If the batch weight differs from the
theoretical value by more than 0.5 percent,
discard the batch.

g) Rest the batch for at least 30 minutes and up to
24 h.

Stage 2 — Final mixing procedure

Duration Cumu-

(min) lative

(min)

a) Cool the internal mixer to a
temperature of 40 ± 5°C with

full cooling water on the rotors.
Start the motor and raise the
ram.

b) Leave the cooling water on and 0.5 0.5
the steam off. Roll all the

sulphur and the CBS into one-
half of the masterbatch and
charge into the mixer. Add the
remaining portion of the
masterbatch. Lower the ram:

c) Allow the batch to mix until a 2.5 3.0
temperature of 110°C or a total

time of 3 min is reached,
whichever occurs first.

d) Immediately pass the batch through a laboratory
mill with a mill opening set at 0.3 mm and at a
temperature of 50 ± 5°C.

e) Pass the rolled batch endwise through the rolls
six times.

f) Sheet the batch to approximately 6 mm and
check, weigh. Remove sufficient sample for
curemeter testing, if required.

g) Sheet the batch to approximately 2.2 mm for
preparing test slabs or to the appropriate
thickness for preparing ring specimen.

3.2.2.2 Method B

Internal mixer for initial and mill for final mixing
Stage 1 — Initial mixing procedure

IS 10016 (Part 6) : 2000

Prepare the initial mix in accordance with procedure
outlined in3.2.2X (Stage 1)

Stage 2 — Final mill mixing procedure

Adjust the mass of all material (that is masterbatch,
sulphur and CBS) to give a final batch mass of four
times the formula mass,

NOTE — AU null openings should be adjusted to maintain a
good rolling bank at the nip of the rolls mixing. If this is not
obtained with the settings specified hereunder, small
adjustments to mill openings may be necessary:

Dura- Cumu-
tion lative

(min) (min)

a) Set and maintain the mill roll 1.0 1.0
temperature at 40 ± 5°C and the mill

opening at 1.5 mm. Band the
masterbatch and band round the front
roll.

b) Add the sulphur and the CBS slowly to 1.0 2.0
the batch.

c) Make six 3/4 cuts from each side. 1.5 3.5

d) Cut the batch from the mill. Set tbe mill \J5 5.0
opening to 0.8 mm and .pass the rolled

batch end-wise through the rolls six
times.

e) Sheet the batch to approximately 6 mm and check, weigh.
Remove sufficient sample for curemeter testing, if required. If
the weight differs more than 0.5 percent from the theoretical
value, discard the batch.

Sheet the batch to approximately 2.2 mm for preparing test
slabs or to the appropriate thickness for preparing specimens.
Cool the compound on a flat dry metal surface at 23 ± 3°C for
1 6 h and RH £ 55 percent.

3.2.23 MethedC — Mill mixing procedure

The standard laboratory batch mass, in grams, shah
be based on four times the formula mass. Adjust the
mill roll cooling conditions to maintain a temperature
of 35 ± 5°C throughout the mixing operations.

NOTES

1 Methods A and B, which give better diipension of the
ingredients, are to be preferred if an internal mixer is available.

2 All mill openings should be adjusted to maintain a good
rolling bank at the nip of the rolls during mixing. If this is not
obtained with the settings specified hereunder, small
adjustments to mill openings may be necessary:

a)

b) Add the zinc oxide and the stearic acid 2 3
evenly across the rolls. Make two -3/4

cuts from each side.

c) Add the carbon black evenly across the 15 to 18 18 to 21

rolls at a uniform rate. When about half
the black has been incorporated, open the
rolls to 1.8 mm and then add the
remainder of the black. Make hvo 3/4 cuts
from each side, allowing 30 s between
each cut. Be certain to add the black that
has dropped into the mill pan.

Duration

Cumu-

(min)

lative

(min)

Band the rubber with the mill opening 1

1

set at 1.3 mm.

Dumtion Cumu-

(min) latjve

(min)

d) Add the oil (omit from Formula 2 for 8 to 10 26 to 31
OEBR) very slowly drop by drop.

e) Add the sulphur and the CBS. 2 28 to 33

f) Make six successive 3/4 cuts from each 2 30 to 35
side.

g) Cut the batch from the mill, set the mill 2 32 to 37
opening to 0.8 mm and pass the rolled

batch end-wise through the rolls six
times.

h) Sheet the batch to approximately 6 mm and check, weigh the
batch. Remove sufficient sample for curemeter testing if re-
quired. The weight should not differ more than 0.5 percent
from the theoretical value, if more discard the batch.

j) Sheet the batch to approximately 2.2 mm for preparing teat
slabs or to the appropriate thickness for preparing ring speci-
mens. Cool the compound on a flat dry metal surface at 23 *
3°C for 1-24 h and RH < 55 percent.

NOTE — It is sometimes easier and mote practical to combine
steps 3.2.23(c) and 3.2.2.3(d) above, either by premixing the
oil and black together-and then adding the oiled black directly
to the rubber on the mill as described in 4JL23(c) and
thus omitting 4.2.23(d) or by adding carbon black and oil
alternately.

3.2.2.4 Method D — Miniature Internal Mixer (MM)
procedure

a) For general mixing procedure.

b) Mix with the head temperature of the

miniature internal mixer maintained at
60 ± 3°C and the rotor speed set at 6.3 to
63 rpm.

c) Prepare the rubber by passing it through a

mill one time with the temperature set at
40 ±3°C and an opening that would give
approximately 5 mm thick sheet. Cut the
sheet into strips that are approximately
2 5 mm wide.

Dura- Cumu-
tion lative

(min) (min)

a) Charge the mixing chamber with 0.0 0.0
the rubber strips lower the ram,

and start timer.

b) Masticate the rubber. 0.5 0.5
c) Raise the ram, add zinc oxide, 1.0 7.5

sulphur, stearic acid and TBBS
that have previously been blended
taking cam to avoid any loss.

d) Add portions of carbon black 1 2.5
and oil alternately sweep the

orifice and lower the ram.

e) Allow the batch to mix, raising 6.5 9.0
the ram momentarily to sweep

down if necessary.

f) Turn off the motor, raise the ram, remove the mixing
chamber, and discharge the batch. Record the
maximum batch temperature indicated if desired.

IS 10016 (Part 6) : 2000

g) Pass the batch through a mill at 40 ± 5°C and

0.5 mm opening once then twice at 3 mm

opening,
h) Check the batch mass and record. If it differs from

the theoretical value by more than 0.5 percent,

discard the batch.

4 CONDITIONING OF COMPOUNDS

Conditioning all batches produced by methods A, B,
C or D at a standard laboratory temperature for 1 to
24 h after mixing and prior to vulcanizing as per
IS 13867.

5 EVALUATION OF WLCANIZATION
CHARACTERISTICS

5.1 Evaluation According to. Stress-Strain
Properties

5.1.1 Vulcanize sheets at r45°C for 25, 35 and 50
min.

Alternatively, vulcanize sheet at 150°C for 20, 30 and
50 min. The recommended cure time for the
miniature internal mixture compound if 35 min at
M5°C.

5.1.2 Condition the vulcanized sheets for 16 to 96 h
at a standard laboratory temperature and humidity
defined in IS 13867.

5.13 Measure the stress-strain properties in
accordance with IS 3400 (Part 1).

5.2 Evaluation According to Oscillating Disc
Curemeter Test

Measure the following standard test parameters:

M u A/ H , ts\, f c (50) and f c = (90)

in accordance with IS 11720 (Part 2) t using the
following test conditions:

Oscillation frequency : 1.7 Hz (100 cycles/

min)
Amplitude of oscillation : 1°C arc

Selectivity.

: To be selected to give
at least 75 percent full
scale deflection

NOTE — With some
rubber, 75 percent may not
be attainable.

Die temperature

:160±1°C

Pre-heat time

:None

ANNEX A

. (Clause 3.2.1)

INTERNAL MIXER

A-l The internal mixer should have a nominal

capacity of approximately 1000 CC.

A-2 The rotor speed(s), ram pressure and coolant
<- flow of the internal mixer should be such that the
conditions specified in 3.2.2.1(e), 3.2.2.2(c) and
3.233(e) will be accomplished.

A-3 The batch size should be the nominal capacity of
the internal mixer measured in cubic centimetres,
multiplied by the density (+ 0, - 10 percent).

NOTE — If an old or worn internal mixer is used, the batch
muss should be increased accordingly.

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote
harmonious development of the activities of stardardization, marking and quality certification of goods and
attending to connected matters in the country.

Copyright

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without the prior permission in writing of BIS. This does not preclude the free use, in the course of
implementing the standard, of necessary details, such as symbols and sizes, type or grade designations.
Enquiries relating to copyright be addressed to the Director (Publication), BIS

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed
periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are
needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards
should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue
of 'BIS Handbook' and 'Standards: Monthly Additions'.

This Indian Standard has been developed from Doc: No. PCD 14 (1058).

Amendments Issued Since Publication

Amend No.

Date of Issue

Text Affected

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