Open Mill
Mixing
In some cases, mixing must be accomplished in a two-roller open mill. Roll speed ratio
1.25:1, slow (front) roll temperature
40°C, fast roll
55°C
< p>, the best results can be achieved. The following open mill mixing process is recommended:1.1.
Roll a portion of the polymer into a smooth continuous strip with a small rolled edge. It is best to leave a small amount of the previous batch of
chlorobutyl rubber
as a "primer" to help add new polymer and subsequent
Glue compound
Ingredients.
1.2.
Add
scorch
inhibitors, acid acceptors,
stearic acid
And gradually add a quarter of the filling in small amounts.
1.3.
Add the remaining polymer and widen the roller distance to retain less rolling accumulation glue.
1.4.
Gradually add filler in small amounts, and adjust the width of the roller spacing to retain less rolling accumulation glue as the weight of the material increases. Reinforcing fillers can be added before
plasticizer
. Plasticizers can be added gradually along with non-reinforcing pigments.
1.5.
Finally add the
vulcanizing agent
to ensure that the batch temperature is lower than
105° C. Exceeding
105°C
Rubber may appear
General Guidelines
1.
Recommended points Mix the chlorobutyl rubber compound in two stages. In the first non-production stage (masterbatch), addition of
zinc oxide
, other desulfurizing agents and
accelerators
.
2.
Compared with the use of general-purpose rubber compounds, the weight of the bicycle may be about
5% higher
to< /p>
10%. Be sure to use a high enough bike weight to avoid trapping air bubbles in the compound and to ensure good shear to disperse the compound ingredients.
3.
The temperature of the polymer during storage cannot be too low. The use of low temperature
polymers
may lead to poor
dispersion
of ingredients and polymerization in the materials. Things clump together. The minimum requirement is that the polymer should reach room temperature conditions before use, preferably preheated (e.g. at
40°C
24
hours). Caution should be exercised when preheating
halogenated butyl rubber
as polymer degradation may occur
31, 33.
For
Internal mixer mixing
1.
Zinc oxide is the vulcanizing agent of chlorobutyl rubber and can be used in Added in the final refining stage.
2.
Anti-scorch agent
(
Magnesia
) in the early stage of the first stage Add for best results.
3.
Plasticizer is added late to allow as much shear of the compound as possible early in the mixing cycle.
4.
Discharging temperature of masterbatch or non-production rubber exceeds
145°C
may cause polymer failure< /p>
Dehydrohalogenation reaction
, thereby reducing the vulcanization performance.
5.
The weight of the bicycle in the second step should be the standard weight of the internal mixer.
6.
To improve the dispersion of polymer and
carbon black
, the polymer in the internal mixer needs to be
Mash
about
30
seconds before adding other ingredients. This increases the rate at which the filler is incorporated into the polymer and generally reduces the overall mixing time.
7.
Higher discharging temperature can lead to reduced scorchability of the rubber material and damage to the viscosity and adhesion.
8.
The chlorobutyl rubber compound is usually left on the cold roll of the flake open mill. In order to minimize the rubber material wrapping the roller or sticking to the rear roller, the temperature of the front roller can be lower than the temperature of the rear roller (5°C
to
10°C
temperature difference).
9.
As with general
elastomer
mixing, the addition of plasticizers and oils can be delayed to promote carbon black incorporation , and a small amount of carbon black can be added together with the oil to prevent the rotor from slipping.
If variable drive speed is present, mastication is taking place.
From:
Li Xiuquan
Studio.