Function of rubber internal mixer:
The purpose of rubber plasticization is to shorten the
macromolecular chain of rubber under mechanical, thermal, chemical
and other effects, so that the rubber temporarily loses its
elasticity and increases its plasticity to meet the process
requirements in the manufacturing process.
For example: to make the compounding agent easy to mix, easy to
calender and press out, the molded pattern is clear, the shape is
stable, increase the fluidity of the pressed and injected rubber,
make the rubber easy to penetrate into the fiber, and improve the
solubility and adhesion of the rubber.
Of course, some low-viscosity and constant-viscosity rubbers are
sometimes not necessarily plasticized, domestic standard granular
rubber, standard Malaysian rubber (SMR).
The plasticization of raw rubber by internal mixer belongs to
high-temperature plasticization, with the lowest temperature above
120℃, generally between 155℃-165℃.
Raw rubber is subjected to high temperature and strong mechanical
action in the internal mixer cavity, which causes severe oxidation
and can obtain ideal plasticity in a short time. Therefore, the
main factors affecting the internal mixer for raw rubber
plasticization are:
1. Equipment technical performance, such as rotation speed, etc.,
2. Process conditions, such as time, temperature, wind pressure and
capacity, etc.
The plasticization of rubber is closely related to its chemical
composition, molecular structure, molecular weight and molecular
weight distribution. Due to the different characteristics of
natural rubber and synthetic rubber in structure and performance,
it is generally easier to plasticize natural rubber, while it is
more difficult to plasticize synthetic rubber. As for synthetic
rubber, isoprene rubber and chloroprene rubber are close to natural
rubber, followed by styrene-butadiene rubber and butyl rubber, and
nitrile rubber is the most difficult.
The plasticity of raw rubber is related to the difficulty of the
entire manufacturing process of the product, and directly affects
the physical and mechanical properties of the vulcanized rubber and
the performance of the product.
If the plasticity of raw rubber is too high, the physical and
mechanical properties of the vulcanized rubber will be reduced. If
the plasticity of the raw rubber is too low, it will cause
difficulties in the subsequent processing, making it difficult to
mix the rubber evenly, and the semi-finished product surface is not
smooth when calendering and extruding, and the shrinkage rate is
large. It is difficult to control the size of the semi-finished
product. During calendering, the rubber is also difficult to rub
into the fabric, causing the rubber curtain fabric to peel off,
which greatly reduces the adhesion between the fabric layers.
Uneven plasticity will cause inconsistency in the process
performance and physical and mechanical properties of the rubber,
and even affect the inconsistent performance of the product.
Therefore, correctly mastering the plasticity of raw rubber is an
issue that cannot be ignored.
75L Rubber Kneader Mixer Banbury Kneader Dispersion Kneader Machine
