Rubber, ethylene-propylene-diene (EPDM)

BS ISO 4097:2020 pdf free.Rubber, ethylene-propylene-diene (EPDM) – Evaluation procedure.
The mixing technique in each method can be modified to achieve a good dispersion of all the ingredients. The LIM conditions shall be the same during the preparation of a series of identical mixes for each batch mixed. At the beginning of each series of test mixes, a machine-conditioning batch shall be mixed using the same formulation as the mixes under test. The LIM shall be allowed to cool down to 60 °C between the end of one test batch and the start of the next. Temperature control condition shall not be altered during the mixing of a series of test.
6.3.2.2 Method Al — Single stage mixing with LIM
The final temperature of the batch discharged after mixing shall not exceed 120 °C. If necessary, adjust the batch mass, head temperature, or rotors speed, so that this condition is met.
Compounding materials other than rubber, carbon black, and oil can be added to LIM batches more precisely and with greater ease if they are previously blended together in the proportions required by the formulation. Such blends can be made using a mortar and pestle, by mixing for 10 mm in a biconical blender with intensifier bar turning, or by mixing in a blender for five 3 s-periods and scraping the inside of the blender to dislodge materials stuck to the sides after each 3 s-mix. A Waring’) blender has been found suitable for this method.
CAUTION一If mixed longer than 3 s, the stearic acid can melt and prevent good dispersion.
NOTE An example of mixing procedure for LIM is as follows.
a) Load the rubber, lower the ram and allow the rubber to be masticated.
b) Raise the ram and add the pre-blended zinc oxide, sulfur, stearic acid, and accelerators, taking care to avoid any loss. Then add the carbon black and oil, sweep the orifice, and lower the ram.
c) Allow the batch to mix.
d) Turn off the motor, raise the ram, remove the mixing chamber, and discharge the batch. Record the maximum batch temperature.
e) After discharging the mixed batch, immediately pass it through a laboratory mill with its mill opening set at 0,8 mm and at a temperature of 50 °C ± 5 °C.
1) Pass the rolled batch endwise through the rolls six times.
g) Sheet the batch to approximately 6mm. Check-weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than —1,5 % to +0,5 %, discard the batch and re-mix.
h) Remove sufficient material for cure testing.
I) Sheet the batch to approximately 2,2 mm for preparing test sheets or to the appropriate thickness for preparing ISO ring test pieces in accordance with ISO 37.
j) Leave the batch for 30 mm to 24 h after mixing, if possible, at standard temperature and humidity as defined in ISO 23529.
Method A2一Two-stage mixing with LIM
Initial mixing procedure
a) Adjust the temperature of the internal mixer to achieve a final mix temperature of 150 °C in about 5 min. Close the discharge door, set the rotor at 8 rad/s (77 r/min), start the rotor, and raise the ram.
b) Load the rubber, the zinc oxide, the carbon black, the oil, and the stearic acid. Lower the ram.
c) Allow the batch to mix.
d) Raise the ram and clean the mixer throat and the top of the ram.Lower the ram.
e) Discharge the batch when the temperature reaches 150 °C or after 5 min, whichever occurs first.
f) Immediately pass the batch three times through a laboratory mill with its mill opening set at 2,5 mm and at a temperature of 50 °C土5 °C. Check-weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than -1,5 % to +0,5 %, discard the batch and re-mix.
g) Leave the batch for 30 min to 24 h after mixing, if possible, at standard temperature and humidity as defined in ISO 23529.
Method A3一Two-stage mixing using a LIM for initial mixing and a mill for final mixing
Stage 1一Initial mixing procedure
a) Adjust the temperature of the internal mixer to achieve a final mix temperature of 150 °C in about 5 min. Close the discharge door, set the rotor at 8 rad/s (77 r/min), start the rotor, and raise the ram.
b) Load the rubber, the zinc oxide, the carbon black, the oil, and the stearic acid. Lower the ram.
c Allow the batch to mix.
d) Raise the ram and clean the mixer throat and the top of the ram.Lower the ram.
e) Discharge the batch when the temperature reaches 150。C or after 5 min, whichever occurs first.
f) Immediately pass the batch three times through a laboratory mill with its mill opening set at 2,5 mm and at a temperature of 50 °C土5 °C. Check-weigh the batch (see ISO 2393). If the mass of the batch differs from the theoretical value by more than -1,5 % to +0,5 %, discard the batch and re-mix.
g) Leave the batch for 30 min to 24 h after mixing, if possible, at standard temperature and humidity as defined in ISO 23529.
Stage 2一Final mill mixing procedure
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, small adjustments to the mill openings might be necessary.
The standard laboratory mill batch mass, in grams, shall be based on twice the formulation mass.
The standard laboratory mill batch mass, in grams, shall be based on twice the formulation mass. The surface temperature of the rolls shall be maintained at 50。C土5。C throughout the mixing.
Mix the zinc oxide, stearic acid, oil, and carbon black together in a suitable container before starting to mix.
NOTE 1 In formulations 1, 2, and 4, some of the oil can be withheld to be added at step 6.3.3 c.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 beiow, small adjustments to the mill openings might be necessary.
a) Band the rubber on the fast roll with the mill set at 50 °C 5 °C and a 0,7 mm opening.
b) Add the mixture of oil, carbon black, zinc oxide and stearic acid evenly across the mill with a spatula.
NOTE2 In formulations 1, 2, and 4, some of the oil can be withheld to be added at step c).
c When about half of the mixture is incorporated, open the mill to 1,3 mm and make one 3/4 cut from each side. Then add the remainder of the mixture, opening the mill to 1,8 mm. When all the mixture has been incorporated, make two 3/4 cuts from each side. Be sure to add any material that has fallen into the mill-pan.BS ISO 4097 pdf free download.Rubber, ethylene-propylene-diene (EPDM)