The document discusses compounding, which is the process of intimately mixing ingredients into a homogeneous mass. There are various criteria and factors that influence compounding, including selecting the appropriate polymer and ingredients based on requirements. Additives can be incorporated at different stages, and various mixing methods are used depending on the material properties and production needs, including dry mixing, batch mixing, continuous mixing, and screw extrusion. Key compounding methods include single and twin screw extruders, which efficiently mix ingredients using heating elements and intermeshing screw motions.

1. COMPOUNDINGCOMPOUNDING

2. DefinitionDefinition
The Process by which ingredients are
intimately mixed together into as nearly a
homogeneous mass is known as
compounding.

3. CRITERIA FOR COMPOUNDINGCRITERIA FOR COMPOUNDING
• Selection of polymer.Selection of polymer.
• Selection of compounding ingredients.Selection of compounding ingredients.

4. SELECTION OF POLYMERSELECTION OF POLYMER
 The performance requirement of the intendedThe performance requirement of the intended
end use.end use.
 The economic factors.The economic factors.
 The availability of suitable and processingThe availability of suitable and processing
equipment.equipment.

5. Selection of compounding ingredientsSelection of compounding ingredients
REQUIREMENT:-REQUIREMENT:-
•Their degree of effectiveness.Their degree of effectiveness.
•The efficiency of processing ingredients.The efficiency of processing ingredients.
•The condition of processingThe condition of processing
•The requirement of the end useThe requirement of the end use
•The environmental exposure to which theThe environmental exposure to which the
product will be subjected.product will be subjected.

6. FACTORS THAT INFLUENCEFACTORS THAT INFLUENCE
COMPOUNDINGCOMPOUNDING
• Physical form & melting characteristics of thePhysical form & melting characteristics of the
polymer considered .polymer considered .
•Degree of dispersion or solubilisation of theDegree of dispersion or solubilisation of the
additive in the final mixture.additive in the final mixture.
•Physical form of the plastics raw material orPhysical form of the plastics raw material or
compound to be produced.compound to be produced.

7. METHODS OF INCOPORATINGMETHODS OF INCOPORATING
ADDITIVESADDITIVES
• Added to the monomer is before or during theAdded to the monomer is before or during the
production of the polymer.production of the polymer.
•Added during the working up of the polymer.Added during the working up of the polymer.
•Added in a separate manufacturing step.Added in a separate manufacturing step.
•Incorporated directly before or during moldingIncorporated directly before or during molding
of a plastic to a semi-finished product orof a plastic to a semi-finished product or
finished article.finished article.

8. Addition of additives before or duringAddition of additives before or during
a polymerisation processa polymerisation process
•Additives should be inert.Additives should be inert.
•Used by the producer of the base resins.Used by the producer of the base resins.
Examples-Examples-
Stabilization of impact resistant PS and preStabilization of impact resistant PS and pre
stabilasation of PVC produced by suspentionstabilasation of PVC produced by suspention
polymerisation.(in both cases antioxidants arepolymerisation.(in both cases antioxidants are
added to the monomers)added to the monomers)

9. Addition of additives during theAddition of additives during the
working up of the polymerworking up of the polymer
•Used by polymer manufacturer.Used by polymer manufacturer.
•Additives used must satisfy specificAdditives used must satisfy specific
requirements determined by the process such asrequirements determined by the process such as
emulsifiability , solubility in certain solvents ,emulsifiability , solubility in certain solvents ,
low volatility or stability to hydrolysis.low volatility or stability to hydrolysis.
•Polymer must be in dispersed form.Polymer must be in dispersed form.
Example- In modification of styrene polymer,Example- In modification of styrene polymer,
such as ABS.such as ABS.

10. Methods of CompoundingMethods of Compounding
There are four basic methodsThere are four basic methods
– Dry mixing,Dry mixing,
– Batch mixing,Batch mixing,
– Continuous mixing,Continuous mixing,
– Compounding by Screw extruder.Compounding by Screw extruder.
The selection of the method determined byThe selection of the method determined by
–Condition of the material,Condition of the material,
–The volume of end product required,The volume of end product required,
–The sensitivity of the material to breakdownThe sensitivity of the material to breakdown

11. Dry MixingDry Mixing
 Dry mixing the plastic with its additives in aDry mixing the plastic with its additives in a
500 pound capacity paddle mixer.500 pound capacity paddle mixer.
 The paddles are turned at 30 to 90 seconds orThe paddles are turned at 30 to 90 seconds or
until the mix is homogeneous.until the mix is homogeneous.
 If the mix is too long, it will develop lumps ofIf the mix is too long, it will develop lumps of
glass, while too short a mix will produce anglass, while too short a mix will produce an
unequal dispersion of glass fibres.unequal dispersion of glass fibres.
 Dry mixer are preferred for powders, plasticDry mixer are preferred for powders, plastic
pellets with fibers and also for mixingpellets with fibers and also for mixing
plasticizers with PVC.plasticizers with PVC.

12. Types of Dry mixersTypes of Dry mixers
 There are four types of dry mixers:There are four types of dry mixers:
– High speed impellers,High speed impellers,
– Ribbon mixers,Ribbon mixers,
– Paddle mixers andPaddle mixers and
– Drum tumblersDrum tumblers..

13. Dry mixerDry mixer
 The mixer consists of an enclosed container withThe mixer consists of an enclosed container with
a higher speed impeller mounted at the bottom.a higher speed impeller mounted at the bottom.
 An impeller is similar to the rotating blades of aAn impeller is similar to the rotating blades of a
helicopter.helicopter.
 The impeller is capable of 80 to 3600 revolutionsThe impeller is capable of 80 to 3600 revolutions
per minute (RPM). Mixing is fast with materialsper minute (RPM). Mixing is fast with materials
blended within 2-4 minute cycles.blended within 2-4 minute cycles.
 Heat generated during the mixing process mustHeat generated during the mixing process must
be drawn off through a cooling jacket to retardbe drawn off through a cooling jacket to retard
decomposition of the material and to block thedecomposition of the material and to block the
development of lumps.development of lumps.

14. Drum TumblerDrum Tumbler
 Drum tumblers are popular with moldingDrum tumblers are popular with molding
operation for the dispersion of powderedoperation for the dispersion of powdered
colorants with the plastic pellets.colorants with the plastic pellets.
 In a drum tumbler, plastic pellets (withIn a drum tumbler, plastic pellets (with
approximately 1 to 2% colorant) areapproximately 1 to 2% colorant) are
placed in a 250 gallon drum and tumbledplaced in a 250 gallon drum and tumbled
dry for approximately 30 minutes.dry for approximately 30 minutes.
 Drum tumblers are used when the additivesDrum tumblers are used when the additives
disperse easily throughout the mixturedisperse easily throughout the mixture
without tending to lump or cluster together.without tending to lump or cluster together.

15. High Speed MixtureHigh Speed Mixture

16. Continue……Continue……
 High speed mixture is widely used for PVC dryHigh speed mixture is widely used for PVC dry
blending and for the dispersion of colorants,blending and for the dispersion of colorants,
pigments etc….pigments etc….
 And also it is using for mixing polymer powderAnd also it is using for mixing polymer powder
with pellets.with pellets.
 HSM is made of impellers mounted in theHSM is made of impellers mounted in the
bottom of stationary vessel.bottom of stationary vessel.
 Rotational speed of impellers is upto-1000rpm.Rotational speed of impellers is upto-1000rpm.
 The motors are using for rotating impellers.The motors are using for rotating impellers.

17. Two Roll MillTwo Roll Mill

18. Continue……Continue……
 Two roll mills are used mostly for mixingTwo roll mills are used mostly for mixing
materials with coarse particles.materials with coarse particles.
 In roll mills, the size reduction takes placeIn roll mills, the size reduction takes place
between two rolls can have either a smooth or abetween two rolls can have either a smooth or a
profiled surface.profiled surface.
 It is reducing the particles size from 1mm to˃ ˃It is reducing the particles size from 1mm to˃ ˃
0.010mm.0.010mm.
 Rolls are rotating as counter-rotating only.Rolls are rotating as counter-rotating only.
 Toll roll mill are mainly using in calenderingToll roll mill are mainly using in calendering

19. Banbury mixers :

20.  The Banbury mixer is a brand of
internal batch mixer, named for inventor Fernley
H. Banbury.
Banbury batch mixer consists of cylindrical
chamber or shell with in which materials to be
mixed are deformed by rotating blades or rotors.
The blade motion causes the mixture to be
shear between blade and tip and shell and
creating shuffling of material Cycle time 2-4 min
Size 50-75 kg Producing large shapeless lumps.
Banbury mixers

21. Cont……
Internal batch mixers such as the Banbury
mixer are used for mixing or
compounding rubber and plastics. Its invention
resulted in major labor and capital savings in
the tire industry.
It is also used for reinforcing fillers in a resin
system.

22. Ribbon BlenderRibbon Blender

23. Continue……Continue……
 Ribbon Blender is useful for convectiveRibbon Blender is useful for convective
mixing.mixing.
 In most of convective mixers, a mixing rotorIn most of convective mixers, a mixing rotor
within a static housing, moving groups ofwithin a static housing, moving groups of
particles from one region to another.particles from one region to another.
 Ribbon mixtures are available both as batchRibbon mixtures are available both as batch
mixture as well as continuous mixture.mixture as well as continuous mixture.
 The rotational speed in ribbon blender isThe rotational speed in ribbon blender is
typically in the range of 10 to 60 rpm.typically in the range of 10 to 60 rpm.


24. Planetary MixturePlanetary Mixture

25. Planetary MixturePlanetary Mixture
 The mixing blade is set off center and is carriedThe mixing blade is set off center and is carried
on a rotating arm. It therefore travels round theon a rotating arm. It therefore travels round the
circumference of the mixing bowl whilecircumference of the mixing bowl while
simultaneously rotating around its own axis.simultaneously rotating around its own axis.
 This is therefore a double rotation similar toThis is therefore a double rotation similar to
that of a spinning planet rotating around thethat of a spinning planet rotating around the
sun, hence the name.sun, hence the name.

26. Conti………..
 Planetary Mixers are used for dry mixing and
dough mixing.
 The homogenous mixing if various
lngredients of different densities in different
proportions for solid/solid, liquid/solid, and
liquld/Iiquid is achieved effectively by the use
of Planetary Mixer.

27. Continue…Continue…
 Planetary Mixers for the preparation ofPlanetary Mixers for the preparation of
ointment, toothpaste, creams.ointment, toothpaste, creams.
 The blades each rotate on their own axes, andThe blades each rotate on their own axes, and
at the same time on a common axis, therebyat the same time on a common axis, thereby
providing complete mixing in a very shortproviding complete mixing in a very short
timeframe.timeframe.

28. ExtrudersExtruders
 Screw extruders are the process tool used inScrew extruders are the process tool used in
compounding, injection molding, injectioncompounding, injection molding, injection
blow molding, extrusion, and extrusion blowblow molding, extrusion, and extrusion blow
molding.molding.
 Screw extrusion technology is used as theScrew extrusion technology is used as the
plastic mixing and melting device.plastic mixing and melting device.
 GF are efficiently compounded with plasticGF are efficiently compounded with plastic
using screw extruders.using screw extruders.
 Two TypesTwo Types
– Single Screw ExtruderSingle Screw Extruder
– Twin Screw ExtruderTwin Screw Extruder

29. A single screw extrudersA single screw extruders
 It classified by the ratio of the length of theIt classified by the ratio of the length of the
screw to the inside diameter of the screw.screw to the inside diameter of the screw.
Standard extruders have 30 to 1 ratios.Standard extruders have 30 to 1 ratios.
 The size of extruders range from smallThe size of extruders range from small
laboratory models with 1/2 inch diameters tolaboratory models with 1/2 inch diameters to
large production extruders with 8" diameterlarge production extruders with 8" diameter
barrels.barrels.
 Consist of long steel screw which rotates steelConsist of long steel screw which rotates steel
tube called barreltube called barrel
 Extruder outputs range from a few pounds anExtruder outputs range from a few pounds an
hour up to 1,000 pounds per hour.

30. Continue…Continue…
 Barrel, is wrapped with heating elements toBarrel, is wrapped with heating elements to
maintain the barrel at the melt temperature ofmaintain the barrel at the melt temperature of
the plasticthe plastic..
 The plastic is pumped from one end of theThe plastic is pumped from one end of the
screw to the other by rotating the screw.screw to the other by rotating the screw.
 The rate at which the plastic moves from oneThe rate at which the plastic moves from one
end of the extruder to the other is controlled byend of the extruder to the other is controlled by
the speed of the screw.the speed of the screw.

31. Feed Zone: Transport the material from hopper to
compression zone.
Compression Zone: Compacts, eliminates air gap
-Transport the material from
compression to metering zone.
- Softens the material
Metering zone: Melts, Mixes, the material
pressurizes and pumps the melt.
Zones of Extruder & its Functions

33. Twin Screw ExtruderTwin Screw Extruder
 The efficiency of the mixing action of theThe efficiency of the mixing action of the
single screw extruder compounder depends onsingle screw extruder compounder depends on
maintaining higher friction between the wall ofmaintaining higher friction between the wall of
the barrel and the material than between thethe barrel and the material than between the
materials and the screw surface.materials and the screw surface.
 If the friction is higher on the screw surface,If the friction is higher on the screw surface,
plastic will stick to the screw surface,plastic will stick to the screw surface,
decompose and clog the mixing process.decompose and clog the mixing process.

34. Conti……..
In a single screw, extruder's plastic pastes,
flakes. Sometimes low bulk density materials
tend to stick to the screw surface.
To overcome these restrictions, the twin screw
extruder was developed.
The twin screw extruder has two screws that
are arranged side by side and intermesh.
The intermeshing action of the two screws
constantly self-wipes the screw flights.

35. ContinueContinue
 It is impossible for plastics to stick to the screwIt is impossible for plastics to stick to the screw
surface. The positive pumping action of thesurface. The positive pumping action of the
intermeshing screws allows for theintermeshing screws allows for the
compounding of all forms of plastic materialscompounding of all forms of plastic materials
not possible with a single two stage extruder.not possible with a single two stage extruder.

36. Continue…Continue…
There are two type of rotatingThere are two type of rotating
1.1. Co-rotating.Co-rotating.
2.2. Counter –rotating.Counter –rotating.
Co-rotating:Co-rotating: When two screws rotates along
same side in a barrel then the phenomena is
called co-rotating

37. Continue…Continue…
Counter-Rotating:Counter-Rotating:
When the two screws rotates the different side
in a barrel, then the phenomena is called
counter-rotating.

38. Thank youThank you