ISO 2476:1996 download.Rubber , butadiene ( BR ) Solution-polymerized types-Evaluation ocedures.
e) DiscNirge the batch at a temperature of 170 °C or after a total time of 6 mm, whichever occurs first. 2,0 6,0
f) Immediately pass the batch three times through a laboratory mdl with a mill opening of 5,0 mm and a temperature of 50°C ± 5°C. Check-weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than + 0,5 % or — 1,5 %, discard the batch and remix.
5.2.2.1.2 Stage 2— FInal mixing procedure
Dura- Cumulat
tion lye time
(mm) (mm)
a) Cool the internal mixer to
a temperature of
40 °C ±5°C with full cooling water on the rotors.
Start the motor and raise
the ram.
b) Leave the cooling water on and the steam off. Roll all the sulfur and the TBBS into one-half of the masterbatch and load Into the mixer Add the remaining portion of the maaterbetch
Lowertheram. 0,5 0,5
c) Allow the batch to mix until
a temperature of 110 °C or
a total time of 3 mm is
reached, whichever occurs
first. 2.5 3.0
d) Immediately pass the batch through a laboratory mill with a mill opening set at 0,8 mm and at a temperature of 50 °C ± 5 °C.
e) Pass the rolled batch endwise through the rolls six times.
f) Shoot tho batch to approximately 6 mm Check- weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than + 0,5 % or — 1,5 %, discard the batch and re-mix. Remove sufficient material for cure- meter testing.
g) Sheet the batch to approximately 2,2 mm for preparing test sheets or to the appropriate thickness for preparing ISO ring specimens in accordance with ISO 37.
5.2.2.2 Method B — Internal mixer for initial and
mill for final mixing
5.2.2.2.1 Stage 1 — Initial mixing procedure
Proceed in accordance with 5.2 2.1 .1.
5.2.2.2.2 Stage 2 — Final mill mixing procedure
Cut 720,0 g (in the case of non-oil-extended rubber) or
660,0 g (in the case of oil-extended rubber containing
37,5 % oil) from the masterbatch. Weigh out four
times the formula mass of the curatives (i.e. 60 g of
sulfur, 3,6 g of TBBS, etc.).
A good rolling bank at the nip of the rolls shall be maintained during mixing. If this is not obtained with the nip settings specified hereunder, make small adjustrnents to the mill openings.
Dura- Cumulattion ive time
(mm) (mm)
a) Set and maintain the mill roll temperature at 35°C±5°C and the mill opening at 1,5 mm. Band the masterbatch around
the front roll. 1,0 1,0
b) Add the sulfur and the TBBS slowly to the batch. Sweep up any material which has fallen into the mill pan and add it to the
mix. 1,0 2,0
c) Make six 3/4 cuts from
each side. 1,5 3,5
d) Cut the batch from the mill. Set the mill opening to 0,8 mm and pass the rolled batch endwise through the
rolls six times. 1,5 5,0
e) Sheet the batch to approximately 6 mm. Check- weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than + 0,5 % or —1,5 %, discard the batch and re-mix. Remove sufficient material for cure- meter testing.
1) Sheet the batch to appfoxilnately 2,2 mm for preparing test sheets or to the appropriate thickness for preparing ISO ring spocimons in accord ance with ISO 37.
5.2.2.3 Methods Cl and C2 — Mill mixing procedures
Solution-polymerized butadiene rubbers are difficult to process on a mill. Methods A and B, which give better dispersion of the ingredients, are preferred if an internal mixer is available. If this is not the case, two mill mixing procedures may be used:
— method Cl, which may be used for solutionpolymerized but8diene rubbers, whether oil- extended or not;
— method C2, which is limited to non-oil-extended rubbers but gives easier mixing and leads to better dispersion of the ingredients
Methods Cl and C2 will not necessarily give identical results for non-oil-extended solution-polymerized butadiene rubbers. In laboratory cross-checks or in a series of evaluations, the same procedure shall therefore be used in all cases.
5.2.2.3.1 Method Cl
The standard laboratory batch mass, in grams, shall be based on three times the formulation mass (i.e 3×182,40g=547,20g or 3×167,40g=502,20g). Adjust the mill roll cooling conditions to maintain a temperature of 35 °C ± 5 °C throughout the mixing
A good rolling bank at the nip of the rolls shall be maintained during mixing. If this is not obtained with the nip settings specified hereunder, make small adjustments to the mill openings.
Dura- Cumulattion ive time
(mm) (mm)
a) Band the rubber with the
mill opening set at 1,3 mm. 1.0 1,0
NOTE 3 Non-oil-extended rubbers may require longer milling to achieve a good band
b) Add the zinc oxide and the
stearic acid evenly across
the rolls Make two 3/4
cuts from each side 2.0 3.0
c) Add the carbon black
evenly across the rolls at a
uniform rate. When about
half the black has been in
corporated, open the rolls
to 1.8 mm and then add
the remainder of the black.
Make two 3/4 cuts from
each side, allowing 30 s
between each cut. Be cer
tain to add the black that
has dropped into the mill 15,0 to 18.0 to
pan. 18,0 21,0
d) Add the oil (omit from oil- extended BR) very slowly 8,0 to 26.0 to
drop by drop. 10,0 31,0
e) Add the sulfur and the
TBBS. Sweep up any ma
terial which has fallen into
the mill pan and add it to 28,0 to
the mix. 2,0 33,0
the 17 laboratories that participated in the programme, on each of two days approximately one week apart Formula 1 contained a non-oil-extended BR, while formula 2 contained an oil-extended BR.
Only method Cl of this International Standard (mill mixing) was used for preparing the mixes.
The mixes were prepared from special samples of all the necessary materials, sent to e8ch laboratory prior to the actual testing. For each material, the samples woro drawn from a uniform and homogeneous lot. Stress-strain tests were conducted on cured sheets of each nf th mixes or compounds as specified by the test programme
9.2.2 Determinations of modulus (stress at 300 %), tensile strength and percent elongation were made, taking as the result the median of five individual determinations, as specified in ISO 37. All 17 laboratories pertorrned the test using dumb-bell test pieces Five of the laboratories also performed the test using iiiiy test pieces. The precision thus evaluated is a type 2 precision, and the time period for repeatability and reproducibility is on a scale of days.
9.3 Precision results
9.3.1 The precision results are given in table 2 for dumb-bell test pieces and in table 3 for ring test pieces.
The symbols used in tables 2 and 3 are defined as follows:
r = repeatability, in measurement units. This is the vdlue below which the absolute difference between two “within-laboratory” test results may be expected to ho with a specified probability.
(r) = repeatability, in percent (mLative).
The two test results are obtained with the same method on nominally identical test material under the same conditions (same operator, apparatus and laboratory) and within a specified time period: unless stated otherwise, the probability is 95 %.
R = reproducibility, in measurement units. This is the value below which the absolute difference between two “between-laboratory” test results may be expected to lie with a specified probability
(R) reproducibility, in percent (relative).
The two test results are obtained with the same method on nominally identical test material under different conditions (different laboratories.