Introduction To Polymers
And Compounds
In TPE’s
Polymers
• If we think of atoms, for example Carbon (C)
and Hydrogen (H) as building blocks we can
make many different structures by piecing
different blocks (atoms) together.
• Not all atoms go together but if we can build a
stable structure we can make bigger building
blocks called Monomers.
Polymers
• So if we take Carbon (C) and Hydrogen (H)
we can make the simple monomer Ethylene.
Polymers
• If we join lots of these “monomer” building
blocks together we then make a “polymer”,
this word comes from Poly meaning many
and mer which means unit as in Monomer
(One Unit) , hence “many Monomers” (or
many units).
Polymers
• If we think of a polymer as a chain we can think of
each monomer as a link in that chain. The more links
we have the longer the chain is, this is known as the
molecular weight (Mw) of the polymer and can greatly
affect properties such as strength, recovery and melt
flow.
Low Mw
High Mw
(e.g. Kraton 1651 has a higher Mw than Kraton 1654)
Polymers
• The polymer chains form entanglements between
each other and this influences properties
• The longer the chains the more entanglements, this
increases properties such as strength and recovery
but decreases properties like the melt flow rate.
Polymers
• Different Monomers can be produced and attached
together to make different polymers, but also we can
start to combine more than one Monomer to form
more complicated polymers. These are known as
Block Copolymers
• SBS (Calprene 419) is a Block Copolymer made from
Styrene Monomer and Butadiene Monomer
Formulations
• Our formulations at VTP are based upon
combinations of polymers
• Although we add other non-polymer ingredients it is
the polymers that influence the main properties of the
compound
• Typically we would combine at least one “rubbery”
material with at least one “plastic” material
• The benefit of this is that we have a material that
shows properties of rubber at room temperatures but
can moulded or extruded like a plastic
SBS
[Styrene] – [Butadiene] – [Styrene]
• “Rubbery” Material
• Fina 409, Calprene 419, Calprene 411, Kraton D-1101 are all
SBS.
• Used in lower cost compounds but has lower performance.
• Degrades quite easily above 200°C, especially if left at this
temperature.
• Sometimes difficult to disperse (i.e. nibs – Europrene)
• Poor resistance to UV.
• Medium capacity for retaining oil
SBS
[Styrene] – [Butadiene] – [Styrene]
Different SBS grades are made by:
• Using different ratio’s of [Styrene] to
[Butadiene]
• Making the chains longer or shorter (Mw)
• Altering the structure of the chains
• Extending with different amounts of oil
SEBS
[Styrene] – [Ethylene] – [Butylene] – [Styrene]
• Rubbery Material
• Kraton 1650, Kraton 1651, Kraton 1654, Calprene C6174S,
Septon 4055
• More expensive material than SBS but has superior properties
• Stable over 230°C and can remain at high temperatures for
reasonable periods of time without any or much degredation
• Can be difficult to disperse but easier than some SBS
• Very Good resistance to UV
• Extremely high capacity for retaining oil
SEBS
[Styrene] – [Ethylene] – [Butylene] – [Styrene]
Different grades of SEBS are made by:
• Using different ratios of the monomer blocks
• Mw (Chain Length) is usually the biggest
difference between grades
EPDM
[Ethylene] - [Propylene] - [Diene] Modified
• EPDM is a synthetic rubber
• Nordel IP3745, Royalene 694 and Royalene 539 are EPDM
rubbers
• EPDM is slightly more expensive than SBS but not as expensive
as SEBS
• EPDM is stable up to around 230°C but if left at temperatures
above 200°C for any length of time can begin to degrade
• Fairly easy to disperse in normal TPE style compounds. More
complicated in TPV (XL) compounds
• Very good resistance to UV
EPDM
[Ethylene] [Propylene] [Diene] Modified
Different grades of EPDM are made by:
• Using different Ethylene to Propylene ratio’s
• Using different Diene’s for modification
• Extending with different oil amounts
Polypropylene (PP)
[Propylene]n
• Plastic material
• Novolen 1100N, BP 100GA12, Moplen HP500N are all grades
of PP
• Plastics we use at VTP tend to be more economical than
“rubbery” materials
• PP is very stable and would not degrade until well above SBS
and SEBS degradation temps, even after prolonged periods
• Dispersion is not usually an issue with plastics
• We have to make sure PP melts though, this happens at 160 165°C but we usually need to go higher than this to ensure that
all of the material gets to this temperature
• PP has no real issues with UV attack
Polypropylene (PP)
[Propylene]n
Different PP grades are usually made by:
• Using different structures
• Different Mw
• Provide different melt flow materials
Polyethylene (PE)
[Ethylene]n
• Plastic material
• Flexirene CM50, Flexirene MR50 and Eraclene MP94
are all types of PE
• Again PE is more Economical than the “Rubbery”
materials we use
• As with PP, PE is very stable from degradation
• Dispersion is not really an issue as long as we melt
the PE. The melt temp of PE is around 135 to 145°C
(this varies depending on type of PE)
• PE has no real issues with UV
Polyethylene (PE)
[Ethylene]n
Polyethylene's are a bit more complicated in the
types available, typical variants are:
• Based on densities (due to varying amounts
of crystallisation) this can give quite different
materials
• Different Mw materials
• Different melt flow materials
Polystyrene (PS)
[Styrene]n
• Plastic Material
• Empera 116 is a PS material
• PS is more economical than “rubbery” materials but is more
expensive than PP or PE
• PS is quite stable but is more prone to problems than PP or PE
• Dispersion again is not much of an issue but we have to soften
material enough to compound in properly. PS doesn’t actually
melt like PP or PE but softens enough around 145 - 155°C
• PS can have some issues with UV
Polystyrene (PS)
[Styrene]n
Different grades of PS are made by:
• The amount of styrene in the polymer chain
• The Mw of the grade
• Different rubber types and amounts added to
improve impact resistance (HIPS)
Compounds
400 Series (SBS)
• Example “Dryflex 400601”
• Based on SBS (Kraton D-1101C)
• Can be used for Injection Moulding and
Extrusion
• Would be used for general purpose low cost
mouldings typically
Compounds
400 Series (SBS)
Dryflex 400601 Formulation:
• SBS – Main Polymer Base – Main Influence on compound
properties
• PP – Plastic Phase – Influences compound properties and helps
to process efficiently
• Oil (Edelex) – This oil suits SBS the best. Used to soften the
material and improve flow and process efficiency
• Filler – Calcium Carbonate (e.g. Calmote UF) – Main use is to
extend the compound and hence “cheapen” it as this material is
significantly lower in cost than polymer
Compounds
500 Series (SEBS)
• Example “Dryflex 500600”
• These grades are unfilled
• Based on SEBS (Kraton G1651)
• Can be used for Injection Moulding and Extrusion
• Would be typically used for general purpose more
demanding mouldings that require very easy
colouring or a clean/transparent appearance
• These would be used over the 400 Series if the
application is for outdoors
Compounds
500 Series (SEBS)
Dryflex 500600 Formulation:
• SEBS – Main Polymer Base – Main Influence on compound
properties
• PP – Plastic Phase – Influences compound properties and helps
to process efficiently
• Oil (Primol) – This oil suits SEBS the best and is medically
approved (also suitable for food contact materials). Used to
soften the material and improve flow and process efficiency
• Stabilisers – Antioxidants and UV stabilisers (e.g.
Irganox/Tinuvin or Polyad which is a pre-blend) – The use of
these is to prevent or slow down the degradation from heat and
oxygen when processing and UV rays during service.
Compounds
600 and 660 Series (SEBS)
• Example “Dryflex 600600 or 660600”
• These grades are filled and semi-filled respectively
• Based on SEBS (Kraton G1651)
• Can be used for Injection Moulding and Extrusion
• Would be typically used for general purpose more demanding
mouldings
• These would be used over the 400 Series if the application is for
outdoors and the 500 series if a higher density is required or if
the clean/transparent nature of the 500 series is not required
and for cost purposes these grades are suitable
Compounds
600 and 660 Series
Dryflex 600600 or 660600 Formulation:
•
SEBS – Main Polymer Base – Main Influence on compound properties
•
PP – Plastic Phase – Influences compound properties and helps to
process efficiently
•
Oil (Primol) – This oil suits SEBS the best and is medically approved
(also suitable for food contact materials). Used to soften the material
and improve flow and process efficiency
•
Stabilisers – Antioxidants and UV stabilisers (e.g. Irganox/Tinuvin or
Polyad which is a pre-blend) – The use of these is to prevent or slow
down the degradation from heat and oxygen when processing and UV
rays during service.
•
Filler – Calcium Carbonate (e.g. Calmote UF) – Main use is to extend
the compound and hence “cheapen” it as this material is significantly
lower in cost than polymer
Compounds
9000 Series (TPO)
• Example “Dryflex 9012-001”
• These grades are based on EPDM Rubber mixed
with a PP plastic
• These grades can be filled or unfilled
• These can be used for injection moulding or extrusion
• Usually used for economical injection moulding,
especially in automotive. Car bumpers are the
biggest usage for this material (not from VTP
material)
Compounds
9000 Series (TPO)
• EPDM – One of the main polymer bases – Big influence on
product properties
• PP – Plastic phase and one of the main polymer bases – Big
influence on product properties and processing
• Calcium Stearate – Process Aid – Acts an internal lubricant to
aid processing both when compounding and moulding/extruding
• Stabilisers – Antioxidants and UV stabilisers (e.g.
Irganox/Tinuvin or Polyad which is a pre-blend) – The use of
these is to prevent or slow down the degradation from heat and
oxygen when processing and UV rays during service.
Compounds
XL Series (TPV)
• Example “Dryflex XL60100-001”
• These grades are based on EPDM Rubber mixed with a PP
plastic like a TPO, but the Rubber phase is vulcanised.
• These grades can be filled or unfilled but usually conatin a small
amount of filler
• These can be used for injection moulding or extrusion
depending on the actual grade
• Usually used for higher end mouldings or extrusions that require
better temperature resistance or better aggressive fluid
resistance (Automotive under bonnet)
Compounds
XL Series (TPV)
•
EPDM – One of the main polymer bases – Big influence on product properties
•
PP – Plastic phase and one of the main polymer bases – Big influence on
product properties and processing
•
Oil (Primol) – This oil suits EPDM the best and is medically approved (also
suitable for food contact materials). Used to soften the material and improve flow
and process efficiency
•
Cure Package – Provides the chemical reaction that vulcanises the EPDM
rubber
•
Stabilisers – Antioxidants and UV stabilisers (e.g. Irganox/Tinuvin or Polyad
which is a pre-blend) – The use of these is to prevent or slow down the
degradation from heat and oxygen when processing and UV rays during service
•
Process Aid – Fatty Acid (e.g. Crodamide E) – Works as an internal lubricant
when compounding and moulding/extruding. Also migrates to the surface to form
a greasy layer that helps with de-moulding and helps material flow through the
die when extruding
Compounds
4000 Series (Glazing)
• Example “Vitaprene 4058-101”
• These grades are based on SBS mixed with a PE
plastic (LLDPE) (Also other polymers incorporated)
• These grades are usually reasonably well filled to
reduce raw material costs
• These grades are predominantly for extrusion
• Usually used for glazing gaskets and seals
Compounds
4000 Series (Glazing)
•
SBS – The main base polymer – used for cost purposes
•
EPDM – Also used in relatively high amount, improves properties such as UV resistance
without using lots of expensive SEBS
•
PE – The main plastic component for processing and properties
•
SEBS – Used in small amount to improve some of the poorer properties of the other
polymers
•
PP – Used in small amounts to influence specific properties and processing
•
Oil (Combination) – Used for softening, cost reduction and property/processing influence
•
Stabilisers – Essential with these grades due to nature of SBS for heat and UV and the fact
that service of these materials is typically outdoors in the direct view of the sun
•
Fillers – Essential for lowering raw material costs due to competitive market and low
margins
•
Black M/B – Contains Carbon Black which is used to provide the black colouration
•
Process aid – Fatty Acid – Essential to help flow through the die and help prevent build up of
die dross or shark-skin effects
Compounds
Obviously there are many more polymers and
additives we use, but what we have covered is
the main bread and butter of VTP compounds
and raw materials.
We have only covered very basics of polymers
as well but the concepts we have looked at
should help to show why we use the different
materials and how to some degree the
formulations are developed