Sartomer Products
For Plastic Modification
Barrier Properties
Compatibility
Dielectric Properties
Compression Set
Impact Strength
Heat Resistance
Flexibility
Adhesion
TABLE OF CONTENTS
SARTOMER’S PRODUCTS FOR PLASTIC MODIFICATION................................................4
PRODUCT SELECTION FOR POLYMER MODIFICATION...................................................5
SMA® RESINS IN THE PLASTICS INDUSTRY........................................................................6
SMA® RESINS AS POLYMER ADDITIVES..............................................................................7
SMA® RESINS AS COUPLING AGENT IN FILLED POLYPROPYLENE COMPOUNDS...9
SMA® IMIDES IN POLYPROPYLENE - COATING ADHESION...........................................10
SMA ® RESINS AS POLYAMIDE MODIFIER..........................................................................12
THE VERSATILITY OF (METH)ACRYLATES IN PEROXIDE CURED THERMOPLASTIC
ELASTOMER VULCANIZATES...............................................................................................15
POLYBUTADIENE-BASED THERMOPLASTIC URETHANES: CHEMISTRY AND
APPLICATIONS........................................................................................................................23
HEALTH, SAFETY, AND ENVIRONMENTAL........................................................................29
Sartomer’s Products For Plastic Modification
Ricon® Resins Krasol® Resins
Ricon® resins, having a wide range of vinyl content on Krasol® resins comprise mainly liquid hydroxyl-
their polybutadiene or poly(butadiene-ran-styrene) terminated homopolymers of butadienes. The
hydroxyl-terminated Krasol® resins having 1.9
backbones, serve as high performance additives in the
plastic industry. The basic homopolymers based on functionalities per chain are ideal for making
polybutadienes and random copolymers based on thermoplastic polyurethanes (TPUs) and stable
butadiene and styrene along with their malenized prepolymers. The hydrogenated hydroxyl-terminated
Krasol® derivatives can improve the weatherability
derivatives can be used as a non-extractable process
aid and low temperature tackifier. However, the and thermal stability of the polyurethanes or other
maleinized derivatives can also be used as adhesion polymers derived from them. Although hydroxyl-
terminated Krasol® resins share many commonalities
promoters to take advantage of the interaction
with Poly bd® resins with respect to applications,
between the grafted anhydride functionality and polar
Krasol® resins stand out in the preparation of stable
surfaces of the substrates. They can also modify
prepolymers and TPUs. Acrylate-capped Krasol®
plastics, such as nylon, through reactive extrusion to
enhance its specific properties. Ricon® resins also resins are available commercially for photo-curing
possess very low dielectric constants and are excellent applications.
ingredients in laminating resins for printed wiring
board manufacturing. All Ricon® resins are available SMA® Resins
SMA® copolymer resins, having a wide range of
in liquid form. To facilitate handling, certain grades are
dispersed with solid carrier or packaged in preweighed styrene:maleic anhydride ratios, have been used as high
low-melt bags to customers� specifications. performance additives for the plastics industry. The
copolymers are an alternating styrene-maleic anhydride
Poly bd® Resins structure at 1:1 styrene:maleic anhydride ratio, and the
Poly bd® resins are liquid, hydroxyl-terminated styrene segments become longer as the ratio is
homopolymers of butadienes. The unique structure of increased to 8:1 styrene:maleic anhydride. As the
the Poly bd resins provides properties which surpass styrene content changes, the polarity of the copolymer
conventional polyether and polyester polyols in is varied from very polar (low styrene content) to less
polyurethane systems. These novel Poly bd® resins polar (high styrene content). This allow the products
having 2.5 functionalities per chain can be used in to be compatible with and used in combination with
different types of plastics. The SMA® products are
preparing castable elastomers, caulks, sealants,
membranes, sponges, foams, adhesives, coatings, highly heat resistant, with glass transition temperatures
propellant binders, potting and encapsulating ranging from 104 to 155°C. In addition there are ester
compounds, as well as other rubber-fabricated and imide derivatives that have been used in blends
materials. It can also modify poly(ethylene with other thermoplastics to promote the adhesion of
terephthalate) resin for packaging applications. Some coatings to articles made from the blends.
of the outstanding performance characteristics
provided by the Poly bd ®resins include: hydrolytic Acrylate and Methacrylate Monomers
stability, low moisture permeability, low temperature Sartomer offers a number of monomers that function
flexibility, resistance to aqueous acid and bases, low as chemical ly reactive additives or intermediates.
embedment stress, thermal cycling stability, and These monomers react with themselves or other
electrical insulation properties. Many derivatives monomers, oligomers, plasticizers, and resins to form
made from Poly bd® resins, such as acid-terminated polymers. These monomers can be 1) acrylate or
polybutadiene and epoxdized Poly bd® resins, are methacrylate functional 2) monofunctional up to
available commercially from Sartomer as well. multifunctional, etc. Sartomer’s specialty monomers
used as reactive additives for plastics, such as PVC,
4
PE, PP, polycarbonate and polyacrylic can enhance toughness of the compound. They can also be used as
many performance properties including melt flow, chemical intermediates in reactive extrusion processes,
impact, abrasion, chemical and heat resistance, and reactive injection molding, compression molding and
increased surface energy to promote adhesion. These cast polymer applications. Their reaction mechanisms
monomers can also be used in thermoplastic elastomers include free radical such as UV/EB or peroxide,
(TPEs) as coagents to improve the rate and degree of Michael addition reactions involving an amine, or
crosslinking, lower compression set, increase high reactions with an isocyanate if a hydroxyl group is
temperature performance and enhance the overall present.
Polymer Modification
Poly bd® /
SMA® SMA® Ricon® Liquid Metallic
Krasol®
TPUs
Resins Im ides Resins Monomers Monomers
Resins
+ + + + + + +
Adhesion
Barrier
+ + + + +
Properties
Compatibility + + + + + +
Heat
+ + + +
Resistance
Impact
+ + + + + +
Strength
Flexibility + + + + +
Dielectric
+ + + + +
Properties
Compression
+ + + + +
Set
Melt Flow
+ + + + + + +
Index
5
SMA® Resins in the Plastic Industry
SMA® use (at 0.5-5 weight percent) in plastic
Sartomer’s low Mw SMA® resins are used in many
compounds. The maximum temperature for making
plastic applications for miscellaneous purposes. The
blends is set at 230°C.
following table is showing non exhaustive examples of
Type of Plastic C pd R ole of SM A C haracteristic(s) Im proved
AB S H eat stabilizer Color (no yellowish) � M echanical properties
AB S/G lass fiber Coupling agent M echanical properties � T herm al stress -
Adhesion
AB S/P A -6 Coupling agent, Compatibilizer Impact Strength � Elongation at break
AB S/Flam e Retardant (Sb2O 3) Coupling agent Impact Strength � Elongation at break
AB S/PB T /Fiber G lass Coupling agent, Compatibilizer M echanical properties (T ensile Strength)
AB S/SB S/M etal powder (C u, Sn, Coupling agent, Compatibilizer Izod impact strength
Pb)
PA-6& 12/M agnetic filler Coupling agent, Processing aid M echanical properties � M old injection ability
PS/G lass fiber H eat stabilizer, Coupling agent Impact Strength � T hermal stress
PS/PolyetherA m ide Compatibilizer M echanical properties
PV C H eat stabilizer, Polar group T hermal stress � Impact strength � Paintability
PV C/Carbon B lack D ispersing agent Appearance � Electroconductivity
Chlorinated PV C Processing aid M old injection ability
PP/CaCO 3 Coupling agent, M echanical properties
D ispersing agent
PP/T alcum powder D ispersing agent Charpy im pact � Extrudability
PP/PS/B aSo 4 Coupling agent M echanical properties
PP/Clay Coupling agent M echanical properties
PP Polar group Paintability
H D PE/W ood Coupling agent Improved hydrolytic stability,
M echanical properties
6
SMA® Resins as Polymer Additives
â™?
General Description Improved mechanical properties
â™?
SMA® resins are copolymers of styrene and maleic Better dispersion
â™?
anhydride (Figure 1) produced by Sartomer Company. Reduced viscosity
â™?
They are supplied at several co-monomer ratios and Improved adhesion
are available in both anhydride and partial ester forms.
As a result, SMA® resins provide a broad range of Applications
chemical and physical properties.
Surface Modification of Fillers
The SMA® 1000, SMA® 2000 and SMA® 3000 The effect of SMA® resin addition to clay filled and
resins are unmodified copolymers with styrene-maleic fiber glass reinforced polypropylene was examined.
anhydride ratios of 1:1, 2:1 and 3:1, respectively. For clay filled polypropylene, significant increases in
Typical properties are shown in Table 1. SMA ®resins tensile strength and flexural modulus were observed
for each of three composites containing SMA® resins
are free-flowing solids with long-term storage stability.
They are thermally stable resins that are readily melt (see Table 2). In addition, the filler was incorporated
much more easily into the polypropylene when SMA®
blended with many thermoplastic polymers during
extrusion or high-shear mixing. In this regard, they can was used.
be used with filled thermoplastic composites to
provide:
Figure 1: SMA® Resins
Table 1: Typical Properties of SMA® Resins
Melt Viscosity Acid value mg
SMA® Ratio Tg (oC)
Product Mw Mn
(Poise) @ 200oC KOH/g sample
SMA® 1000 1:1 5,000 2,100 ~60,000 465-495 155
SMA® 2000 2:1 7,500 2,700 ~6,000 335-375 135
SMA® 3000 3:1 9,500 3,050 ~3,000 255-305 125
SMA® EF-40 4:1 11,000 3,600 ~750 195-235 115
SMA® EF-60 6:1 11,500 5,500 ~70 141-171 106
SMA® EF-80 8:1 14,400 7,500 ~100 105-135 104
(1) Non-volatile material
7
Table 2: Effect of SMA® Resin on Polypropylene/Clay Composites
Composite1
Tensile Strength (psi) Flex. Modulus (psi) Ult. Elongation %
PP/Clay2/SMA® resin
Yield Break
70/30/0 (3) 3340 374,000 4.6
70/30/1.3 SMA® 1000 4280 4020 423,000 4.4
70/30/1.3 SMA® 2000 4060 3600 426,000 5.3
70/30/1.3 SMA® 3000 4270 4160 451,000 4.1
1) Composites prepared by dilution with virgin PP of 70/30 Clay/PP concentrates containing 3.0 parts SMA® resin.
2) Hydride 10 (Georgia Kaolin Co.)
3) No yield
flexural modulus when the SMA® 2000 resin was
The effect of SMA ® 2000 resin addition to
added to the composite. As with the clay filled
polypropylene/glass composites of varying glass fiber
specimens, the SMA® resin addition was conducted
contents are given in Table 3. Significant improve-
concurrently with dispersion of the glass fibers.
ments were observed for both tensile strength and
Table 3: Effect of SMA® 2000 Resin on Polypropylene/Glass Composites
Composite1
Tensile Strength (psi) Flex. Modulus (psi)
(PP/Glass/SMA® resin)
90/10/0 4000 322,000
90/10/0.4 4400 405,000
70/30/0 2800 523,000
70/30/1.3 3500 545000
50/50/0 820 561,000
50/50/2.1 1900 690,000
1) Composites prepared by dilution with virgin PP of 70/30 Glass/PP concentrates containing 3.0 parts SMA® 2000 resin.
Promotion of Adhesion Table 4 indicates that adhesion to both substrates is
SMA® resin modified polyethylenes were compared improved by the addition of the appropriate SMA®
to unmodified resins in adhesion to aluminum and steel. resin.
Table 4: T-peel Strength of SMA® Resin Modified Polyethylene
T-peel, (lbs./in.)
SM A ® R esin (w t. % )
Substrate
A lum inum Steel
LD PE 1 --- 0.1 0.3
LD PE 1 1000 (10) 0.2 0.6-1.6
LD PE 1 3000 (10) 0.1-2.3 0.5-2.8
LD PE 2 --- 0.3 0.2
LD PE 2 1000 (10) 4.1-5.3 3.7
LD PE 2 3000 (10) 0.2 0.4
1) Dylan 2020F (ARCO polymers, Inc.)
2) Super Dylan SDP 640 (ARCO Polymers, Inc.)
Filler Dispersion trates. In clay filled polyolefins, the dispersion of the
SMA® resins are excellent pigment dispersants. This filler is noticeably improved in the presence of SMA®
resins. SMA® resins should also facilitate the disper-
has been demonstrated in solvent and aqueous base
coating systems as well as in pigment slurry concen- sion of pigments into polyethylene and polypropylene.
8
SMA® Resins as a Coupling Agent in Filled Polypropylene Compounds
SMA® 1000P is a low molecular weight styrene, maleic improvement brought on tubes (32x3) made on a
anhydride copolymer with an approximately 1:1 mole SAMAFOR 6 extruder (30D).
ratio in powder form. It is the Sartomer SMA® resin
SMA® 1000P decreases viscosity of PP/Talcum
with the highest maleic content. It forms low viscosity,
high solids solutions in aqueous bases. It is also used powder compounds. The following chart shows Melt
as a coupling agent in filled polypropylene compounds. Flow Index improvement on filled PP-based
compound for injection molding applications.
SMA® 1000P improves elongation at break of PP/
CaCO3 compounds. The following chart shows
SMA® 1000 Effect on
SMA® 1000 Effect on
PP/CaCO3 Compound
PP/CaCO3 Compound
1800
900
16
40 MFI (230°C, 2.16 kg)
Te nsile Strength at break(Mpa)
Flexion Modulus (Mpa)
Tensile strength at break (Mpa)
800 Flexion Modulus (Mpa)
Elongation st Break(%)
35 Elongation at break (%) 1600
MFI (230°C, 2.16 kg)
700
12
30
600
25 1400
500
8
20 400
1200
15 300
4
10 200
1000
5 100
0
0 PP-100% PP-80%, CaCO3 - PP-89%, CaCO3 -
PP-100% PP-80%, CaCO 3-20% PP-79%, CaCO 3 - 10%,
20% 10%, SMA1000-1%
SMA1000-1%
Type of Plastic Cpd Role of SMA Characteristic(s) Improved
PVC Heat stabilizer, Polar group Thermal stress, Impact strength, Paintability
PVC/Carbon Black Dispersing agent Appearance, Electroconductivity
Chlorinated PVC Processing aid Mold injection ability
PP/CaCO3 Coupling agent, Dispersing agent Mechanical properties
PP/Talcum powder Dispersing agent Charpy impact, Extrudability
PP/PS/BaSO4 Coupling agent Mechanical properties
PP/Clay Coupling agent Mechanical properties
PP Polar group Paintability
9
SMA® Imides in Polypropylene - Coating Adhesion
SMA® Imide resins are low molecular weight SMA® Imide Resins can function as polyimide or
copolymers of styrene and dimethylaminopropyl- polyamine additives, serving as curing catalysts or
amine (DMAPA) maleimide. These products have a surface modifying agents. Typical applications include
high level of tertiary amine functionality, good thermal alkali resistant coatings, adhesives and polymer
stability, low VOC content and form high solids modification.
solutions in organic solvents or, as their cationic salts,
in water.
10
SMA® Imides PP Compounds painting
� Paint used:
A new polyamine additive
� Range of amine indices: 1.6-3.2 BM GR ICEBERG 640 from HERBERTS
� High thermal stability: 5% wt. loss >325°C � Applied with a pneumatic gun after
� Low melt viscosity isopropanol cleaning
� Some miscibility with styrenics and � 3 layers:
polyolefins ¨ primer: 8 mm
� Modifies polymer surface energies ¨ base: 18 mm
¨ topcoat: 30 mm
� 1 week conditioning
SMA® Imides: Adhesion Promoters for Low
Energy Surfaces
PP compounds testing
PP Compounds Karcher Test according to Renault standard D25
PP compounds are modified: 2018
� By thermoplastic elastomer to improve � Temperature: 70°C
� Pressure: 65bars
the impact resistance
� By polar polymers to improve the paint � Time: 30 seconds
� Sample distance: 10
adhesion
Pass
PP plaques formulation and processing:
� PP copolymer+X% TPE+4% SMA-X 1000 I Aging test (24hrs/100°C)
� Mixed on double screw extruder Karcher Test according to Renault standard D25
� Plaques 100x100x3 mm by injection molding 2018
Pass
* Faurecia: Karcher Test (Renault Standard D25 2018)
11
SMA ® Resins as Polyamide Modifier
Interest In Using SMA® Resins
Introduction
Main interests in using SMA® resins in polyamides are:
Polyamides (PA) are one of the most important
� to decrease the MFI, which is of particular
families of thermoplastic polymers. They are used in
importance for many applications such as
many applications such as textile, engineering,
film extrusion or blow molding of polymers;
packaging, and coatings. Starting from various
monomer units and formulating with additives and fillers
� to improve the tensile strength, elongation at break,
enables more and more grades of PA to be tailor-
and impact resistance without the loss of regidity
made.
compromise with the modules in mineral filled
Polyamides.
However, PA producers and compounders are still
looking for improvements such as better processability,
Melt Flow Index Reduction
better thermal properties, better thermoforming
Influences of SMA® resins on the melt flow index
properties, reduced core shifting, reduced gauge
(MFI) are indicated in Tables 1 and 2.
thickness, higher tear strength, increased stability to
hydrolysis, better surface quality, etc.
Addition of SMA® resins to polyamides leads to a
This bulletin presents the effect of SMA® resins on the strong decrease of the MFI. This effect is more
pronounced with the SMA® 1000 grade than with the
melt flow index when they are added to a PA 6 and to
SMA ® 2625 grade. At 0.5 weight percent
a PA 6 filled with glass fibers, as well as the effect on
concentration, SMA® 1000 gives a lower MFI than
mechanical properties of the same PA 6 filled with 30
SMA® 2625. However, increasing the concentration
weight percent of Kaolin. The PA 6 we have used is a
of SMA® 2625 to 1.0 weight percent gives the same
product from ARKEMA, referenced “ORGAMIDE
MFI as 0.5 weight percent of SMA® 1000.
RMNO CD�. Its main characteristics are shown in
Appendix 1.
Main characteristics of SMA® Resins we have used
are summarized in Appendix 1.
Table 1: PA 6/SMA® Resin
°
SMA® Resin (weight %) MFI (2.16kg - 235°C)
PA 6 alone 0 Not measurable � high MFI (low viscosity)
PA 6 + SMA® 1000 0.5 5.0
PA 6 + SMA® 2625 0.5 8.5
PA 6 + SMA® 2625 1.0 4.9
Table 2: PA 6/Glass Fiber (30 wt. %)/SMA® Resin
°
SMA® Resin (weight %) MFI (2.16kg - 235°C)
PA 6 + glass fiber 0 6.6
PA 6 + SMA® 1000 0.5 2.9
PA 6 + SMA® 2000 0.5 2.9
PA 6 + SMA® 3000 0.5 2.9
0.5 weight percent of SMA® Resin 1000, 2000, or
For the same PA 6 filled with 30% by weight of glass
3000 is added.
fiber, the MFI is divided by more than 2 when only
12
Conclusion Multiaxial Impact: Maximum Strength (N)
Adding SMA® Resins to PA 6 enables an MFI Maximum strength Fmax is very low, with about 900 N
when no SMA® Resin is added. Such behavior is not
reduction to be made. This effect is especially
interesting whenever an increase of viscosity is desired. surprising as it has often been observed that the
Examples of such requests are film extrusion or blow introduction of mineral fillers is able to increase rigidity
molding of large components. but generally at the expense of the fracture toughness.
Addition of 1 weight percent of SMA® 1000 or 3000
Choosing the appropriate SMA® Resin and adjusting has brought Fmax value to a very high level: ~ 5700 N
(multiplied by 6) with SMA® 3000, and ~ 6600 N
its concentration in the PA system should help in the
(multiplied by 7) with SMA® 1000.
following:
� better flow control Multiaxial Impact: Energy (J)
� lower and better thickness control The same effect has been observed when considering
� higher productivity impact energy Emax instead of Fmax. Emax has been
increased from ~ 1 J (no SMA® Resin) to ~ 36 J with
1 weight percent SMA® 3000, and to ~ 45 J with 1
Improvement of Mechanical Properties
weight percent SMA® 1000.
Using a blend of PA 6 filled with 30 weight percent of
Kaolin, and incorporating 1 weight percent of SMA®
Charpy Impact (kJ/m2)
Resin system, we have investigated the following
properties: CHARPY impact resistance is largely improved
when adding SMA® Resins. It has been increased by
� tensile strength at break (ISO R 527); more than 70% when adding 1 weight percent of
� SMA® 1000, changing from 14 (no SMA® Resin) to
elongation at break (ISO R 527);
� maximum strength for multiaxial impact and 24 kJ/m2, and this increase reached 85% when using
1 weight percent of SMA® 3000, to 26 kJ/m2.
energy for multiaxial impact, at 23°C, 4.3 m/s,
20 mm impact diameter (ISO 6603-2);
� notched CHARPY impact (ISO 179-82); Flexural Modulus (MPa)
� notched flexural modulus (ISO 178). Addition of 30 weight percent of kaolin to PA 6 gives
a noticeable increase in flexural modulus, from 2100
The kaolin used is a silanized kaolin, “Polarite 102 A� MPa (PA 6 alone) to ~ 3750 MPa. The addition of 1
weight percent of SMA® 1000 to the PA6/ Kaolin
from EEC. Test conditions are indicated in the
Appendix 2. blend leads to a slight decrease of the flexural modulus,
changing from 3750 to 3000 MPa, but it still remains
Tensile Strength at Break (MPa) much above the modulus of the PA 6 alone which is
When adding SMA® 1000 or 3000 to the PA 6, tensile 2100 MPa. For equal SMA® Resin concentration (1
strength at break has been approximately multiplied weight percent), the loss of flexural modulus has been
by 2. It has been increased from 32 (no SMA® Resin) higher with SMA® 3000 (from 3750 to 2450 MPa)
to 61 MPa for SMA® 3000, and has reached 64 MPa than with SMA® 1000 (from 3750 to 3000 MPa).
when using SMA® 1000.
Conclusion
Addition of SMA® Resins to PA 6/Kaolin blends has
Elongation at Break %
Addition of SMA® 3000 increases elongation at break given a remarkable improvement of impact properties
from 20% (no SMA® Resin) to 30% (50% increase). whereas, by comparison, the loss of rigidity appears
This effect is even more spectacular with SMA® 1000 to be very small. In other words, the compromise
since elongation at break then has been changed from between impact strength and modulus is noticeably
20% to 46%, which represents a 130% increase. improved.
13
Appendix 1
Table 3: SMA® Resins Main Characteristics
SMA® Resin SMA® 1000 SMA® 2000 SMA® 3000 SMA® 2625
Styrene Styrene Maleic
Styrene Maleic Styrene Maleic
Maleic Anhydride
Chemical Nature Anhydride Anhydride
Anhydride Copolymer
Copolymer Copolymer
Copolymer Partial Ester
Glass Transition
155 135 125 110
Temperature (Tg) (°C)
Acid Value (mg KOH/g) 465-495 335-375 265-305 200-240
PA 6: “ORGAMIDE RMNO CD� of ARKEMA
Density at 23°C (ISO R 1183 D): 1.13
Tensile strength at yield point (ISO R 527): 70 MPa
Flexion modulus (ISO 178): 2100 MPa
18 kJ/m2
CHARPY impact, notched 23°C (ISO 179-82):
Heat distortion at 0.46 MPa (ISO 75): 193°C
Melting point (ASTM D 789): 218°C
GLASS FIBERS: P 337 from VETROTEX
KAOLIN: “Polarite 102 A� from E.C.C. (Silanized kaolin)
Appendix 2
Extrusion Conditions
Extruder: Ko-Nneader BUSS PR46170/15D
(Single Screw Extruder)
The filler is introduced through the inlet n° 2 in the
Products Introduction:
The matrix and the SMA® Resin are initially dry melting area, using a SODER T20 feeder;
blended, and introduced in the feed hooper using a
The inlet n° 3 is kept open for degasing.
SODER M40B feeder (the rotation speed of the
Cooling of the Extruded Material with Water
filling screw is 245 rpm);
Extrusion Conditions:
°
Area N° 1 2 3 4 5
Temperature (°C) 240 270 290 290 290
Rotation Speed (rpm) 33 33 33 33 33
Extrusion Flow (kg/h) 25 25 25 25 25
Test Pieces:
Mold injected at 240-260°C, the mold temperature being at 40°C
14
The Versatility of (Meth)acrylates in Peroxide Cured
Thermoplastic Elastomer Vulcanizates
Abstract corresponding sulfur accelerators. Coran, Patel, et al
This paper covers the chemistry, physical properties found that thermoplastic elastomers containing finely
and function of (meth)acrylate monomers as dispersed particles of high unsaturation diene rubber
crosslinkers or coagents for peroxide cured in combination with certain phenolic or sulfur-donor
thermoplastic elastomers (TPE’s) based on polyolefins vulcanizing agents yielded superior physical properties
and toughness due to a high state of cure .(6-8) Phenolic
and crosslinkable elastomers. Specifically, the paper
compares peroxide/coagent dynamic vulcanization of cure of TPE’s yields low oil swell and high tensile
TPE’s to phenolic dynamic vulcanization. Additionally, strength but also has drawbacks such as color
it covers the potential to minimize polymer degradation development, moisture sensitivity and toxicity due to
of the polyolefin continuous phase in heterophase formaldehyde emissions.
TPE’s during processing with peroxides by the use of
(meth)acrylate coagents. Free radical vulcanization initiators such as organic
peroxides are not typically used with polyolefin TPE’s
Introduction due to the tendency for the peroxide to either cross-
The use of (meth)acrylate functional monomers as link the polyolefin if it is polyethylene or degrade it due
coagents for peroxide vulcanization or crosslinking of to b-chain scission or vis-breaking if the polyolefin is
saturated and unsaturated ethylene-propylene based polyproylene. This degradation of polypropylene
elastomers during fabrication is well known in the results in lower molecular weight as described by the
literature and has been common practice in the industry mechanism of Figure 1.
since the 1960’s.(1) The combination of peroxide and
(meth)acrylate coagent has found utility as an Vis-breaking of PP with peroxides is done intention-
alternative to sulfur vulcanization of ethylene-propylene- ally in some applications to modify the rheology of the
diene terpolymer (EPDM) in many applications such melt or to initiate grafting of the backbone. However,
as automotive belts, hoses, gaskets, and seal such polymer degradation can result in poor melt
compounds.(2-4) Once these types of elastomers are strength and decreased physical properties.
crosslinked to form strong C-C bonds, however, they
exhibit thermoset behavior and cannot be reprocessed. Recent developments suggest that polymer
degradation can be minimized by the use of
Thermoplastic elastomers (TPE’s), on the other hand, (meth)acrylate coagents. U.S. Patent 6,774,186 cites
are elastomer-thermoplastic heterophase blends that the use of (meth)acrylate coagents with peroxide in
exhibit properties similar to conventional elastomers. rheology modified TPE’s comprised of ethylene a-olefin
The discontinuous elastomer phase in TPE’s can be polymer and polypropylene a-olefin polymer to
crosslinked by dynamic vulcanization in the melt with improve melt strength in calendaring and thermo-
forming applications.(9) In addition, U.S. Patent
the plastic phase to yield a reprocessable material.
These dynamically vulcanized TPE’s were first 6,890,990 cites the use of a combination of free radical
introduced in the 1980’s by Monsanto Company and coagents in a PP/EPDM TPE to optimize the gel
have grown rapidly in signifigance ever since. It has content or degree of crosslinking, yield low color, and
provide good oil swell resistance.(10) Finally, F.R. de
been demonstrated that if the elastomer phase is fully
vulcanized, enhanced performance such as better Risi and J.W.M. Noordermeer have evaluated
mechanical properties, lower compression set and (meth)acrylate coagents with peroxide in PP/EPDM
higher service temperatures can be achieved.(5) TPE’s and found that more stable free radicals are
formed by positioning of the radical on the coagent
Generally, dynamically vulcanized polyolefin-elastomer molecule. This more stable positioning limits chain
fragmentation of the polypropylene.11
TPE’s are prepared by the use of methylol-phenolic
resins catalyzed by a Lewis Acid or by sulfur and
15
Figure 1. b-Chain Scission of Polypropylene in the Presence of Peroxides
1) R � O � O- R R–O* *O–R Homolytic Cleavage
β - Scission
2) 2 R � O * + CH3 CH3 CH3 CH3 CH3 CH3
*
H
Coagents are commonly used with peroxides to materials such as bismaleimides or multifunctional
improve the efficiency of vulcanization of elastomers methacrylate and acrylate monomers which readily
as well as improve the resulting properties. Coagents hompolymerize free radically via addition but can also
for peroxide cure are typically classified as either Type copolymerize with the elastomer through hydrogen
I or Type II. Type II coagents are materials such as abstraction. Therefore, (meth)acrylate functional
trially cyanurate, triallyl isocyanurate, diallyl phthalate monomers can be thermally polymerized with organic
and 1,2-vinyl polybutadienes which are all effective peroxides and serve as crosslinking agents if
for improving the state of cure. Type I coagents are functionality f > 1 as described by the mechanism in
Fig 2.
Figure 2a. Chemistry of (Meth)acrylates
Where R1 = H for acrylates
R1
CH3 for methacrylates
R2 = alkane, cyclic, ester, ether moiety
C O hydroxy, epoxy, acid, amine functionality
H2C C R2
or additional (meth)acrylate functionality
providing crosslinking capability
O
Figure 2. Crosslinking Network Formation
O
O
O
O
R-O* *O-R
*
R-O-H O
O
O
O
Diacrylate
Diacrylate
O
(f > 1)
O
O
O
O O
O
O
O
O
O
O
O
O
O
O
monomers also differ in reactivity and elastic modulus
Methacrylate monomers generally exhibit higher glass
as depicted in Table 1 and Fig. 3.
transition temperature (Tg) and higher hardness than
acrylate monomers. Methacrylate and acrylate
16
Table 1. Acrylate vs. Methacrylate Coagent Reactivity and Mechanical Property Comparison
Coagent Peak Exotherm Time to Peak Elongation @Break Tensile Modulus
Temperature* (oC) Exotherm (oC) (%) (Mpa)
Diacrylate Coagent 301 7 0.6 1600
Dimethacrylate Coagent 43 63 0.7 2100
Triacrylate Coagent 305 12 1.1 1100
Trimethacrylate Coagent 40 22 0.1 3400
Figure 3. Comparison of Acrylate vs. Methacrylate Elastic Modulus
10
10
The dimethacrylate monomer exhibits higher
E'
Erubber modulus and better modulus retention
SR239 - HDDMA
cO
SR238 - HDDA
cO
)
� Since Erubber modulus correlates to
E' (c O
9
[Pa]
10 crosslink density, the dimethacrylate
monomer exhibits better heat/chemical
8
10
-100.0 -50.0 0.0 50.0 100.0 150.0 200.0
Temp [°C]
(Meth)acrylate functionality also affects reactivity and The intent of this paper is to report on the findings of
mechanical properties as depicted in Table 1. Higher an initial evaluation of (meth)acrylate coagents in
functionally also typically results in higher hardness, peroxide cured polyolefin based TPE’s and to discuss
crosslink density, and solvent/fluid resistance. the potential benefits resulting from this work. The
objective was to address several questions regarding
(Meth)acrylate monomers most commonly are liquid their versatility such as: 1) How much coagent can be
resins ranging in viscosity from very low to very used before the TPE properties are reduced and the
viscous. They yield covalent crosslinks when material is no longer processable? 2) What crosslink
polymerized free radically. However, (meth)acrylate density is required to improve compression set and
monomers can also be metallic based fine granular raise Tg enough to increase the TPE’s service
powders which yield ionic crosslinks when temperature? 3) Does peroxide/coagent vulcanization
polymerized. Ionic crosslinking is unique in that the offer improved color and higher modulus/hardness
crosslinks are reversible through high shear or high than conventional methylol-phenolic vulcanization of
temperature as depicted in Fig. 4. This characteristic TPE’s? Finally, the most importantl question is: 4) Can
presents some unique rheological performance in proper selection of methacrylate coagent result in
conventional thermoset elastomers and results in very minimal polypropylene degradation in the TPE to yield
good high temperature flex properties. More recently, good processability and optimal performance?
metallic containing (meth)acrylate functional oligomers
have been developed which have increased organic
solubility and can be provided as viscous liquids.
17
Figure 4. Thermal “Reversibility� of Ionic Crosslinks
ACRYLIC BACKBONE
-
++
++ - ++
++
- ++
HEATING
IONIC
++
DOMAINS
-
++
- COOLING
++ ++
++
CROSSLINKED THERMOSET FLOWING THERMOPLASTIC
The EPDM elastomer utilized had an E/P ratio of 70/
Experimental
30 and contained 4.5% ethylene- norbornene. It had
a Mooney viscosity = 48 ML(1+4)/125oC. The
The Effect of Crosslinking Agent Type on
competitive methylol phenolic curative used was a
Degradation of Polypropylene
brominated octylphenol/formaldehyde resin in flake
Prior to preparation of dynamically vulcanized TPE
form which had a softening point = 90oC and a
compounds, a study was designed to determine the
methylol content of 10%. The peroxide initiator used
effect of the crosslinking agent on degradation of
was a dialkyl peroxide (2,5-Dimethyl-2,5-di-(t-
polypropylene by measuring the melt flow rate. PP
butylperoxy)hexane) having 10% active oxygen and 1
homopolymer was compounded with phenolic cura-
hr T1/2 = 140oC. A bismaleimide derivative was used
tive, peroxide alone and peroxide/(meth)acrylate
as a comparative Type I coagent. This product is a
coagent, respectively, in a Brabender internal mixer at
powder which melts at 195oC and has MW=268. The
160oC and 60 rpm until the torque stabilized. Then,
the temperature was raised to 190oC and speed to (meth)acrylate coagents evaluated were a
developmental long chain diol diacrylate, and
92 rpm. The mixing time did not exceed 8 minutes in
commercially available high performance triacrylate,
the mixer. The compounded formulations are listed in
high performance trimethacrylate, metallic
Table 2 along with the resulting melt flow rates.
(meth)acrylate functional oligomer and a poly-
butadiene diacrylate. The long chain diol diacrylate is
Melt Flow Rate was determined by using a Kayeness
a low viscosity liquid with MW= 266. The high
Melt Indexer following ASTM D1236, Procedure A.
The conditions of the test were 230oC melt tempera- performance triacrylate and trimethacrylate coagents
contain a low color, low volatility non-nitroso amine
ture and 2160 gram piston weight after purging.
scorch retarder to maintain stability during initial
charge to the mixer. The triacrylate MW=298, and
Materials Used for Evaluation
the trimethacrylate MW=340. The metallic coagent is
The formulations prepared in this study are listed in
a viscous diacrylate functional polyester oligomer
Table 3. The polypropylene resin utilized was an
containing Zn with MW= approx. 1200. The
isotactic homopolymer having density = 0.897 and an
polybutadiene diacrylate is a viscous resin prepared
experimental melt flow rate MFR = 9 gms/10 min.
from a high vinyl polybutadiene diol with MW= 2,000.
18
Preparation of Dynamically Vulcanized Once the torque stabilized the peroxide initiator was
added and the temperature was raised to 190oC and
Thermoplastic Elastomers
The preparation of crosslinked TPE’s based on the speed to 92 rpm. The torque and temperature were
polypropylene and ethylene-propylene-diene (EPDM) then monitored for an increase to indicate a measure
elastomer was conducted in a laboratory Brabender of cure. The total cycle time in the mixer for each
internal mixer equipped with roller blades and a torque compound did not exceed 8 minutes. The crosslinked
rheometer for following the polymerization of the TPE compounds prepared were then discharged into
(meth)acrylate coagent. The PP/EPDM weight ratio a pre-heated 10� x 10� stainless steel two-piece cavity
and the peroxide concentration were kept constant. mold with aluminum panel inserts to control the
The bis-maleimide and the (meth)acrylate coagents thickness. The mold was placed into a hydraulic Carver
laboratory press @ 190o for 5 minutes to produce
were evaluated at 0.4 and 4.0% by weight,
respectively. The polypropylene and EPDM polymers plaques for further testing. Thickness of the cured
were charged to the mixer at 160oC and 60 rpm. The plaques varied from 0.75 mm to 1.8 mm depending
additives, including the coagent were then added. on the test parameters.
Table 2. The Effect of Crosslinking Agent on Degradation of Polypropylene
Compound 1 2 3 4 5 6
Polypropylene Homopolymer 200 200 200 200 200 200
Peroxide Initiator 0.45 0.45 0.45 0.45 0.45
Phenolic Curative Package 7.3
High Performance Triacrylate Coagent 0.4 4.0
High Performance Trimethacrylate Coagent 0.4 4.0
Melt Flow Rate (gms/10 mins) 24.8 12.0 17.3 14.9 16.0 10.7
19
Table 3. Summary of Dynamically Vulcanized PP/EPDM Thermoplastic Elastomers
Compound Formulation 1 2 3 4 5 6 7 8
135 135 135 135 135 135 135 135
EPDM
PP Homopolymer 23 23 23 23 23 23 23 23
0.45 0.45 0.45 0.45 0.45 0.45 0.45
Peroxide Initiator
Magnesium Oxide 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30
Antioxidant 0.30 0.40 0.30 0.30 0.30 0.30 0.30 0.30
Stearic Acid 0.60
Zinc Oxide 1.3
Methylol Phenolic Resin 5.4
Diacrylate Coagent 0.4 4.0
Triacrylate Coagent 0.4 4.0
4.0
Trimethacrylate Coagent 0.4
Shore A Hardness 49 50 48 43 53 49 43 48
Mechanical Properties
Tensile Strength (Mpa) 3.0 3.3 4.3 3.4 3.9 2.6 3.3 3.2
Elongation @ Break (%) 553 203 470 218 385 173 637 607
Modulus @ 100% (Mpa) 3.0 2.9 1.9 2.3 1.9 1.9 1.3 1.3
Compression Set (%)
22 hrs @100C Cb 58.0 27.9 55.1 14.5 35.5 29.8 67.0 76.3
Swelling (%)
48 hrs. in Cyclohexane 346 129 252 177 232 185 315 271
48 hrs. in Toluene 263 99 191 136 157 142 232 229
Compound Formulation 9 10 11 12 13 14
EPDM 135 135 135 135 135 135
PP Homopolymer 23 23 23 23 23 23
Peroxide Initiator 0.45 0.45 0.45 0.45 0.45 0.45
Magnesium Oxide 0.30 0.30 0.30 0.30 0.30 0.30
Antioxidant 0.30 0.30 0.30 0.30 0.30 0.30
Metallic Acrylate Coagent 0.4 4.0
PolyBd Diacrylate Coagent 0.4 4.0
Bis-maleimide Coagent 0.4 4.0
Shore A Hardness 47 41 46 48 43 48
Mechanical Properties
Tensile Strength (Mpa) 3.6 3.5 3.7 5.8 2.2 5.6
Elongation @ Break (%) 648 593 561 531 158 342
Modulus @ 100% (Mpa) 1.5 1.7 1.5 2.1 1.7 2.4
Compression Set (%)
22 hrs @100C Cb 63.7 81.8 76.3 56.2 17.1 27.2
Swelling (%)
48 hrs. in Cyclohexane 354 276 318 271 232 130
48 hrs. in Toluene 263 226 247 178 157 105
Evaluation of TPE-V Properties Compression set was measured following ASTM
Physical properties of the vulcanized TPE’s are D395 Method B using stacked 1/2� diameter die-cut
specimens compressed 20�25% at 100oC for 22
reported in Table 3 and were measured as follows:
hours.
Hardness measurements were made with a Shore “A�
durometer following ASTM D2240. The relative crosslink density was determined by
degree of swell on a weight gain basis after immersion
in cyclohexane and toluene, respectively,. at 25oC.
Mechanical properties including tensile strength,
elongation at break and tensile modulus were
measured from die-cut dogbone samples following
ASTM D412.
20
Results and Discussion compounds exhibited better tensile strength and
elongation at lower concentrations but higher modulus
Polymer Degradation from MFR at the higher concentrations. This result may be
The melt flow rate (MFR) results from the attributed to better miscibility in the elastomer phase.
The metallic oligomer coagent and the poly bd®
polypropylene homopolymer compounded with
peroxide, peroxide/(meth)acrylate coagent, and diacrylate coagent both exhibit good tensile strength
phenolic curatives indicate a significant increase. and high elongations but low modulus.
Peroxide alone showed the highest melt flow rate due
to polymer degradation. The high performance The compression set values for the (meth)acrylate
trimethacrylate coagent, which gives a more stable coagent compounds indicate that acrylate coagents
radical, exhibited a melt flow rate similar to the phenolic are more effective at reducing compression set than
curatives. The higher the coagent concentration the methacrylates due to more efficient crosslinking. In
lower the increase in melt flow rate. addition, higher acrylate functionality and higher
acrylate coagent concentration yields better
Vulcanized TPE’s � Physical Properties compression set. The methacrylate coagent, the
The TPE compound vulcanized with the phenolic metallic coagent and the polybd acrylate coagent all
curatives exhibits slightly increased hardness and yielded poor compression set at both concentrations.
tensile strength. This compound exhibits good
compression set and the lowest degree of swell. The percent swell values for the (meth)acrylate
However, the elongation at break was significantly coagents show similar results to the compression set
reduced in this compound due to a high crosslink data in relation to theoretical crosslink density. All of
density. In addition, the resulting TPE was very dark them show lower percent swell in both solvents at the
in color. higher coagent concentration. The metallic oligomer
coagent and the polybd diacrylate coagent, having the
The bismaleimide coagent compound at low lowest acrylate functionality, yielded the highest degree
concentration exhibits reduced hardness and tensile of swell. Although, the percentage of swell observed
properties but good tensile strength, modulus and was still an improvement over peroxide alone. The tri-
elongation at the higher concentration. At low levels methacrylate coagent also gave higher swell values than
the bismaleimide does not get dispersed well enough the triacrylate due to the bulkier methyl group and
in the elastomer phase and does not efficiently lower crosslink density. The diacrylate coagent
crossslink the elastomer. Therefore, it acts as a filler, exhibited the least amount of swell even though it has
resulting in reduced properties. This compound yields a lower theoretical crosslink density than the triacrylate.
better compression set at the low concentration and This result could be explained by the fact that the longer
very good swell resistance at the higher coagent alkane chain has better compatibility and miscibility in
concentration. The higher tensile properties and better the elastomer phase.
compression set at the higher concentration suggest
that some crosslinking of the elastomer phase is Conclusions
occurring. This paper represents an initial study of the utility of
(meth)acrylate coagents in peroxide curable
The high performance trimethacrylate coagent heterophase thermoplastic elastomers based on
compounds exhibit reduced hardness and modulus but polyolefins and high unsaturation diene elastomers. It
increased elongation at both concentrations. The high has been demonstrated that acrylate and methacrylate
performance triacrylate coagent compounds exhibit functional coagents can provide enhanced cross-
slightly higher hardness and modulus at low linking of the elastomer phase to improve such
concentration but poor tensile properties at the higher properties as compression set and solvent resistance
concentration. The long chain diol diacrylate coagent while maintaining good mechanical properties without
color development.
21
It has also been demonstrated that coagent 4. Costin, C. R.; Nagel, W., Coagent Selection for
concentration, coagent type (acrylate or methacrylate) Peroxide-Cured Elastomers, ACS Rubber
and coagent functionality can have an effect on the Division Symposium, Chicago, IL , May 1998
final properties of the vulcanized TPE. In general,
higher coagent levels enhance crosslink density but the 5. Holden, G.; Kricheldorf, H.R.; Quirk, R.P.
kinetics of the reaction, phase compatibility and Thermoplastic Elastomers Third Edition, Hanser
rheology of the melt during mixing and after curing has pps. 143-154.
yet to be studied in detail. Acrylate coagents have also
demonstrated higher crosslink densities from swell 6. Coran, A.Y.; Patel, R.P. Monsanto Company,
data than methacrylates. This can be explained by U.S. Patent 4,104,210.
the fact that acrylates form a less thermally stable
radical which in turn, generates more crosslinking at 7. Coran, A.Y.; Das, B.; Patel, R.P. Monsanto
the mixing temperatures used in this study. Most Company U.S. Patent 4,130,535.
importantly, it has been shown that (meth)acrylate
coagents can help to overcome the deficiencies of 8. Coran, A.Y.; Patel, R.P. Monsanto Company,
peroxide only vulcanization (i.e., PP degradation) and U.S. Patent 4,271,049.
provide compounded TPE’s having similar or
improved performance over conventional phenolic 9. Walton, K.L. Dupont-Dow Elastomers, U.S.
vulcanized systems. Patent 6,774,186.
References 10. Cai, K.; Colvin, H.; Reid, C.; Tran, H. Solvay
1. Dikland, H. Coagents in Peroxide Engineered Polymers, U.S. Patent 6,890,990
Vulcanisations of EPDM, pps. 2, 63 Copyright
1992. 11. de Risi, F.R.; Noordermeer, J.W.M. University
of Twente, Peroxide Cured Ethylene-
2. Morton, M. Rubber Technology, Third Propylene-Diene/Polypropylene (PP/EPDM)
Edition, Van Nostrand Reinhold, pg 297 Thermoplastic Vulcanizates: Effects of
Methacrylate Co-agents on Properties, 167th
3. Costin, C.R.; Nagel, W. , Selecting Acrylic Technical Meeting of the ACS Rubber Division,
Coagents for Hose-Belt Applications, ACS Spring 2005, San Antonio, TX.
Rubber Division Symposium, Paper #53,
Indianapolis, IN April 1999 September 1998,
p.563
22
Polybutadiene-Based Thermoplastic
Urethanes: Chemistry and Applications
Abstract step with a chain extender at 100° C for 10 minutes.
Thermoplastic polyurethanes (TPUs) based on The resulting material was poured into a mold and left
hydroxyl-terminated polybutadiene resins have been to cure at 100°C for 20 hours. Post-curing of the TPU
made and one of them commercialized for the first proceeded at laboratory temperature for seven days.
time. The synthesis and properties are described. The Under these conditions, the addition of a catalyst was
TPU blends with polypropylene have been investi- not necessary, but sometimes dibutyltin dilaurate
gated briefly. (DBTDL) catalyst was added to accelerate the curing.
Introduction In the case of the one-shot procedure, the reaction
vessel was charged with Krasol® LBH or LBH-P, chain
Development of TPUs possessing hardness ranging
from 70-90 Shore A has been reported in the TPU extender and Tinuvin B75, and the mixture was heated
market with researchers being focused on the polyol to 80°C-90°C. Then, Suprasec MPR (preheated to
component[1]. Polyurethanes based on polybutadiene about 45°C) or pure 4,4�-MDI was added. After 3-5
are known for excellent hydrophobicity, hydrolytic and minutes of agitation, the TPU was discharged into a
chemical resistance, electrical insulation properties, and mold and left to cure as described above.
low-temperature elasticity[2-4]. However, until recently,
hydroxyl-terminated polybutadienes available The polyurethane sheets thus prepared were used for
commercially were manufactured by a free-radical the determination of mechanical and physical proper-
polymerization technology (e.g., the Poly bd® resins ties and for the resistance study.
of Sartomer). This technology yields polyols with
functionalities higher than 2.0 that are not applicable Evaluation of Elastomer Properties
for use in TPU systems[5]. Physical and mechanical properties of polyurethane
elastomers were evaluated by the following test
Krasol® LBH and LBH-P polybutadiene diols, methods:
� Shore hardness (ISO 868:1985),
manufactured by Sartomer Czech are anionically
� Tensile stress-strain properties (ISO 37:1994),
polymerized products with very narrow molecular-
weight distributions containing no species with and
� Compression set (ISO 815:1991)
functionality higher than 2.0[6]. Krasol® diols are
available in the molecular weight range from 2,000 to
10,000. The Krasol® LBH resins are terminated by The glass transition temperature (Tg) and the soften-
secondary OH groups and Krasol® LBH-P resins are ing temperature values of TPUs were measured by
terminated by primary OH groups. thermomechanical analysis (TMA).
Experimental Results and Discussion
The following parameters of the formulation were
Preparation of Thermoplastic Polyurethanes tested in order to determine the structure-property
relationship of the Krasol®-based TPUs:
The synthesis of TPUs was performed in a one-liter
� Type of OH groups (primary or secondary) of
glass reactor at normal pressure under a nitrogen
blanket with vigorous agitation. The NCO/OH ratio the polybutadiene diol and its molecular weight,
� Method of synthesis (one-shot or prepolymer
of all formulations was 1.03-1.05. In the case of the
prepolymer procedure, Krasol® LBH diol was reacted procedure),
� Selection of the chain extender, and
with a diisocyanate at 80°C for one hour to yield a
� Hard-segment content.
prepolymer. The prepolymer was mixed in the second
23
The first syntheses were performed using Krasol® The best results with good reproducibility were
LBH 3000 having secondary hydroxyl groups and achieved with EHD and DIPA. The main difference
adopting the prepolymer approach. The formulations between these two extenders is in processing since
numbered 1 through 4 in Table 1 show the comparison DIPA is a solid at ambient temperature. Based on these
of 2-ethyl-1,3-hexanediol (EHD), 2,2,4-trimethyl data, EHD was chosen for further development.
pentane-1,3-diol (TMPD), N,N-diisopropanol aniline
(DIPA), and 1,4-butanediol (BDO) as chain In an attempt to obtain even softer TPUs, a series of
extenders. The use of EHD, DIPA or TMPD led to samples with decreasing hard-phase content was
polyurethanes with Shore hardness of about 80 A, synthesized (Table 1, Formulations 5-8). By decreas-
which may be classified as soft-grade TPUs. Their ing the hard segment content, it was possible to prepare
mechanical properties are comparable with those of TPUs with hardness as low as 55 Shore A. However,
good-quality, general-purpose rubber materials. heat resistance of TPUs using EHD as a chain extender
and having 25% or lower hard-phase content is rather
The use of BDO as an extender in Krasol®-based poor.
TPUs with 35% hard-segment content cannot be
Preparations of the TPU Krasol® LBH 3000/MDI/
recommended with this lab procedure due to serious
problems with demolding, which may be caused by EHD with 35% hard-segment content (Table 1,
the limited miscibility of polybutadiene diols with 1,4- Formulation 1) were carried out repeatedly to check
butanediol (BDO)[7]. However, successful syntheses the reproducibility of the synthesis. The typical
of TPUs based on hydrocarbon polyols have been characteristics of the elastomer were as follows: Shore
reported when using BDO at relatively low hard- A hardness 78-82, tensile strength 15-18 MPa,
segment content (20-23%)[7, 8]. This composition for elongation 500-700%, compression set (70° C, 22
Krasol®-based TPUs was also verified later in one- hours) 50%, softening temperature about 110°C, and
shot formulations. Tg from -39° to -43°C.
With regard to thermal characteristics, the melting Some of the batches were prepared with the addition
point of hard segments formed by MDI and non-linear (1.0%) of Tinuvin B75, a complex polyurethane
chain extenders is significantly lower than that of MDI/ stabilizer. The addition of Tinuvin B75 did not affect
BDO domains[9]. Therefore, the softening temperature the measured elastomer properties.
of TPUs in Table 1 is relatively low. The Tg, on the
other hand, corresponds to the medium-vinyl-type
polybutadiene in the elastomers� soft segments.
Table 1. Characterization of Thermoplastic Polyurethanes Prepared by Prepolymer Procedure: Krasol® LBH 3000/MDI/
Extender
4a
Formulation 1 2 3 5 6 7 8
Extender EHD DIPA TMPD BDO EHD EHD EHD EHD
Hard segment, % 35 35 35 35 30 25 20 15
Hardness, Shore A 77 78 77 - 74 66 55 -
Tensile strength, MPa 18.2 17.2 17.5 - - - - -
Elongation at break, % 410 490 400 - - - - -
Softening temperature, °C 110 110 110 - 100 70 60 50
Glass transition temperature, °C -42 - - - -43 -43 -42 -40
a
Demolding of the sample after 20 hours cure at 100°C was not possible.
24
Thermoplastic Polyurethanes Prepared by One- (Formulations 9 through 11). All of these elastomers
have similar properties; however, the use of Krasol®
Shot Procedure
The Krasol® LBH polybutadiene polyols, although LBH 2000 resulted in a small increase of Shore hard-
having secondary-OH groups, can be used with EHD ness and a slight change in softening and glass transi-
as a chain extender in the preparation of TPUs using a tion temperature.
one-shot procedure. The effect of the synthetic
procedure on the elastomer properties is shown by As mentioned earlier, only a limited amount of BDO
comparing Formulation 1 in Table 1 with Formulation can be added to the formulation. As a result, TPUs
9 in Table 2. A one-shot TPU based on Krasol® LBH could not be prepared in the laboratory with hard-
3000 exhibited somewhat lower hardness, as well as segment content exceeding about 25%. The higher
lower tensile properties, compared with the reactivity of BDO requires the use of the more reactive
Krasol® LBH-P in one-shot systems. A formulation
polyurethane prepared by the prepolymer method.
with Krasol® LBH-P 3000 and BDO yielded a very
Thermal characteristics of both products were
equivalent. soft TPU product with hardness 60 Shore A, good
elongation and relatively high softening temperature
The role of polyol molecular weight and of the type of (Table 2, Formulation 12).
OH groups can also be seen from Table 2
Table 2. Thermoplastic Polyurethanes Prepared by One-Shot Procedure
Formulation 9 10 11 12
Composition
Krasol® LBH 3000, pbw 100 - - -
Krasol® LBH 2000, pbw - 100 - -
Krasol® LBH-P 3000, pbw - - 100 100
EHD, pbw 16.5 15.1 17.0 -
BDO, pbw - - - 6.5
Tinuvin B75, pbw 1.6 1.6 1.6 1.3
MDI, pbw 37.4 39.1 38.2 26.9
Hard segment content, % 35 35 35 25
Physical Properties
Hardness, Shore A 73 76 73 60
Tensile strength, MPa 14.4 15.2 15.9 6.8
Modulus 100%, MPa 7.0 6.5 8.7 2.6
Elongation at break, % 390 460 470 890
Softening temperature, °C 110 90 110 150
Glass transition temperature, °C -40 -35 -41 -44
Molecular Weight Effect on TPU Hardness and 5. Formulation 22 (Table 5) appears to be a good
To determine the relationship between hardness and candidate for the TPU of 90 Shore A hardness. It has
hard segment content with respect to different Krasol® 38% hard segment and good flow under compression
LBH molecular weights, several compositions were molding conditions. The plot of hardness vs. hard
prepared and the hardness values are listed in Table 4 segment is shown in Fig. 1.
25
Table 4. Characterization of Thermoplastic Polyurethanes Prepared by Prepolymer Procedure:
Krasol® LBH 3000/MDI/Extender
Formulation 13 14 15 16 17
Krasol® LBH 3000, pbw 100 100 100 100 100
EHD, pbw 10.36 23.54 37.67 51.79 61.21
MDI, pbw 27.07 50.76 76.14 101.52 118.44
DBTDL (drop) 1 1 1 1 1
Eqs ratio of LBH / EHD / MDI 1 / 2.2 / 3.36 1 / 5 /6.3 1 / 8 / 9.45 1 / 11 / 12.6 1 / 13 / 14.7
Hard segment content (%) 27.2 42.63 53.2 60.52 64.24
NCO% of prepolymer 5.0 9.5 12.97 15.57 16.96
NCO index (eqs ratio of NCO / OH) 1.05 1.05 1.05 1.05 1.05
Hardness (shore A) of cured sheet 69 79 85 90 93
Table 5. Characterization of Thermoplastic Polyurethanes Prepared by Prepolymer Procedure:
Krasol® LBH 2000/MDI/Extender
Formulation 18 19 20 21 22
Krasol® LBH 2000, pbw 100 100 100 100 100
EHD, pbw 45.3 38.82 29.77 23.29 18.12
MDI, pbw 93.02 81.39 65.11 53.48 44.18
DBTDL (drop) 1 1 1 1 1
Eqs ratio of LBH / EHD / MDI 1 / 7 /8.4 1 / 6 /7.35 1 / 4.6 / 5.88 1 / 3.6 / 4.83 1 / 2.8 / 3.99
Hard segment content (%) 58.04 54.59 48.69 43.43 38.39
NCO% of prepolymer 11.54 13.01 10.99 9.28 7.70
NCO index (Eqs ratio of NCO / OH) 1.05 1.05 1.05 1.05 1.05
Hardness (shore A) of cured sheet 96 95 96 94 90
Fig. 1. Hardness data of TPUs from various amount of hard segment using the prepolymer method
TPU Hardness vs Hard Segment Content
100
Krasol LBH 3000
Krasol LBH 2000
90
80
70
60
50
10 20 30 40 50 60 70
Hard Segment (%)
26
Poly bd® 2035 TPU and afflication in polyolefin representative properties are listed in Table 3. It was
blends also successfully produced by the prepolymer method
Poly bd® 2035 TPU is Sartomer’s first commercially in a reactive extrusion process.
available thermoplastic polyurethane based on a
hydroxyl terminated poly butadiene resin. Some of the Other TPU grades of higher and lower hardness will
be developed in the near future.
Table 3. Poly bd® 2035 TPU Typical Physical Properties
Elongation at break, % 559
Hardness Shore A (initial) 86
Modulus, psi 946
Vicat softening point, ºC 52
Specific gravity @ 25 ºC 0.96
Tensile strength at break, psi 1711
Tg, ºC -35
Melt Flow Rate, g/10min @ 190 ºC, 21 N load 8.26
Water vapor transmission (WVT), g/h·m2 0.018
Permeance, g/Pa· S· m2 4.56x 10-9
Poly bd® 2035 TPU/Polyolefin Blends compression molding at 190ºC for testing. The
Syndiotactic polypropylene (Finaplas®) was mixed hardness of the blends decreased from Shore D 55 to
with the Poly bd® 2035 TPU in a Brabender mixing 32 when the TPU content was increased from 2 to
bowl with roller blades at 150ºC. The objective of the 75%. The mechanical properties are listed in Table 6.
experiment was to prepare a soft-feel material. Five The blends appeared to be compatible without
compositions containing 2, 10, 25, 50, and 75% TPU indication of delamination. Microscopic work is in
were prepared and the plaques were made by progress.
Table 6. Physical Properties of Polyolefin/Polybutadiene TPU Blends
Flexural Flexural
Poly bd® 2035 Tensile Elongation @ Tensile
strength** Modulus**
Content (%) strength* (MPa) break* Modulus* (MPa)
(MPa) (MPa)
0 17.3 16 NA NT 379.0
2 13.4 100 7.0 14.7 374.6
10 15.0 228 9.0 12.2 299.0
25 16.1 252 8.7 9.8 249.8
50 7.4 203 6.6 8.9 171.7
75 7.6 422 4.5 1.8 27.3
100 14.0 550 5.6 NT NT
*ASTM D412; **ASTM D790
NA: Not Applicable; NT: Not Tested
Conclusions 2-Ethyl-1,3-hexanediol (EHD) was found to be a
Polybutadiene diols Krasol® LBH (secondary-OH suitable chain extender for Krasol-based TPUs. The
groups) and LBH-P (primary-OH groups) were used TPU of 80 Shore A hardness is available commercially.
in the preparation of thermoplastic polyurethanes 1,4-Butanediol can also be used in polybutadiene-
(TPUs) employing either a one-shot or a prepolymer urethanes. However, reactive extrusion was needed
procedure. to make polyurethanes with high content of hard
segment.
27
5. Poly bd® Resins in Urethane Elastomers,
The polybutadiene backbone provides an exceptional
resistance against aqueous solutions of strong mineral Atochem Technical Bulletin, Atochem North
acids (sulfuric acid, nitric acid) or bases � far superior America, October 1990.
to that of polyether or polyester-based elastomers. 6. Pytela J. and Sufcak, M. “New Anionic
These TPU systems are ideal candidates for adhesive Polybutadiene Diols for Polyurethane
and sealant applications requiring resistance to Systems�, Proceedings of the Polyurethanes
aggressive protic media or the ability to ensure long World Congress 1997, Amsterdam, The
service in humid conditions. Netherlands, September 1997, p. 704.
7. Frisch, K. C., Sendijarevic,A., Sendijarevic, V.,
References Yokelson, H. B., and Nubel, P. O.
1. Lee, S. Thermoplastic Polyurethane Markets “Polyurethane Elastomers Based Upon Novel
in the EU: Production, Technology, Hydrocarbon-Based Diols�, Conference
Applications and Trends, Rapra Technology UTECH 96, The Hague, The Netherlands,
Limited, February 1998. March 1996, Book of Papers, Paper 42.
2. PolyBd®, the Best of Two Worlds, Arco 8. Gerard, E. J. and Schneider, J. K. L. “Non-Polar
Technical. Bulletin, Arco Chemical Co., Div. Long Chain Hydroxyl Compounds Extending
of Atlantic Richfield Co. the Range for Polyurethanes in CASE and
3. Pytela, J., Sufcak, M., Cermak, J. and Drobny, Foam Applications�, Proceedings of the
J. G. “Novel Isocyanate Prepolymers Based on Polyurethanes World Congress 1997,
Polybutadiene Diols for Composite Binders and Amsterdam, The Netherlands, September 1997,
Cast Elastomers�, Proceedings of the p. 552.
Polyurethanes EXPO98, Dallas, September 9. Meckel, W., Goyert, W., and Wieder, W. in
1998, p. 563 Thermoplastic Elastomers: A Comprehensive
4. Pytela J. and Sufcak, M. “Polybutadiene- Review, Legge, N. R., Holden, G. and
Urethane Elastomers with Outstanding Schroeder, H. E. editors, Hanser Publishers
Resistance to Aggressive Aqueous Media�, (1987), p.21.
UTECH 2000 Conference, The Hague, The
Netherlands, March 2000. Conference
Proceedings, Coatings, Adhesives, Sealants and
Elastomers Session, Paper 9.
28
Health, Safety, and Environmental Information
TOXICOLOGY INFORMATION Styrene-Maleic Anhydride Resins:
Some Styrene-Maleic Anhydride (SMA®) products
As with any chemical, the potential health and safety
hazards associated with Sartomer products should be are supplied in powdered or flake form � inhalation
understood to ensure that they are used safely. Review of dust from handling or processing these products
each product’s Material Safety Data Sheet (MSDS), may cause irritation of the respiratory tract and other
which includes specific hazard and precautionary mucous membranes. These materials may also cause
information, prior to working with these materials. eye and skin irritation. The degree of irritation varies
with each product and ranges from slightly irritating
Should you require assistance in an emergency to severely irritating as demonstrated in animal tests.
situation involving a Sartomer Company product, call Some products elicited no irritation response in these
us at 610-692-8401, twenty-four hours a day. tests. Refer to the product’s MSDS for specific
information. In addition, due to their higher molecular
LIQUID (METH)ACRYLIC MONOMERS: weights, these resins are not expected to be ingestion
These products range from minimally irritating to or skin absorption hazards.
corrosive in acute animal skin and eye irritation tests.
Monomers may cause redness or rash, swelling and, SMA® resins supplied as salts in a water solution may
in severe cases, blistering (burns) if skin contact occurs also be irritating to the eyes and skin. In addition,
- the skin irritation response will depend on the respiratory tract irritation may occur upon exposure
conditions of exposure and the irritation potential of to vapors that are generated during the processing of
the product. Symptoms of skin irritation may be these materials.
delayed. Liquid monomers typically do not pose an
inhalation hazard at room temperature. However, Some SMA® resins are reacted with an alcohol to
aerosols or vapors which can be generated from form an ester. Due to their higher molecular weights,
spraying or heating these materials, respectively, may these SMA® esters are not expected to be ingestion
cause upper respiratory tract irritation if inhaled. Some or skin absorption hazards. However, SMA® esters
of these products have been shown to be skin may cause eye, skin and respiratory tract irritation.
sensitizers (substances which cause an allergic skin Hazards of the alcohol(s) used to manufacture these
reaction in susceptible individuals after repeated esters must also be considered –the alcohols may be
exposure) in animal tests. Cases of sensitization in present in small amounts in the final product(s) and
workers have been reported in the published literature vapors from the alcohol(s) may be released during
for a limited number of products. It is important that processing. Refer to the product’s MSDS for specific
skin contact with these products be prevented to information.
ensure that skin sensitization does not occur.
Poly bd®/Ricon®/Krasol® Products
Metallic Coagents: These products are polybutadiene and polybutadiene-
Metallic coagents may cause skin irritation, based polymers. Due to their higher molecular
particularly if skin contact is prolonged. Skin weights, these resins are not expected to be ingestion,
sensitization may also occur. Most metallic coagents inhalation or skin absorption hazards. They may cause
are supplied as powders—dust from these products, slight eye and skin irritation. In addition, respiratory
or vapors created by thermal processing, may cause tract irritation may occur upon exposure to vapors
irritation of the respiratory tract and other mucous that may be generated during processing.
membranes. These products may also cause severe
eye irritation or may be corrosive to the eyes as Some Krasol® products are diisocyanate-based
demonstrated in animal tests. They are typically low polybutadiene polymers. These products often contain
ingestion hazards. free residual diisocyanate at very low concentrations.
29
Diisocyanates are known eye, skin and respiratory All products should be used according the
tract irritants and, more notably, they are skin and manufacturer’s instructions including adherence to
respiratory sensitizers. Refer to the product’s MSDS shelf-life recommendations.
to review the hazards of a particular product and
protective measures that can be implemented to handle Refer to the MSDSs for specific storage recommen-
the product safely. dations for all Sartomer products.
GENERAL HANDLING PROCEDURES & FIRE HAZARDS & PRECAUTIONS
PRECAUTIONS In the event of a fire, chemical products can become
As with all industrial chemicals, it is important to inhalation hazards � they can be carried by smoke;
prevent exposure through the use of protective vapors and combustion products from burning
equipment, proper work practices and engineering materials may be extremely irritating. In the case of
controls. monomer and oligomer products, amine acrylates and
M-Cure products, heat from a fire may also initiate
The following precautions should be observed for an uncontrolled polymerization, which can cause
general handling practices: closed containers of these products to rupture,
- ensure a clean, well ventilated work environment; possibly spreading the fire.
- avoid skin contact by wearing impervious gloves;
- wear eye protection such as goggles; Fire fighters should wear self-contained breathing
- wear other protective equipment as appropriate; apparatus in addition to eye, face and body protection.
- review the MSDS prior to working with a material. Extinguish fires with dry chemical, foam, carbon
� If skin contact does occur, wash affected areas dioxide, or water fog and spray from a safe distance
immediately with soap and water. Rinse thoroughly. or protected location. Extinguishing media should be
If eye contact occurs, immediately flush the eye(s) applied gently to styrene-maleic anhydride resins and
with clean water for at least 15-20 minutes. Seek metallic coagents to avoid raising dust clouds, which
medical attention. can create an explosion risk. Cool fire or heat exposed
containers with water fog or spray from a safe distance.
� Minimize the potential for dust explosion, which
can be associated with handling organic powders, GENERAL DISPOSAL PROCEDURES
such as the styrene-maleic anhydride resins, and Persons handling empty product containers should
metallic coagents. Eliminate and control ignition wear protective equipment and handle containers in
sources and use good housekeeping practices an area away from ignition sources because they may
during storage, transfer and handling of these contain residual product. Recommended cleaning
products. procedures for empty steel drums include washing the
containers with a strong soap and water solution,
GENERAL STORAGE INFORMATION followed by a thorough water rinse. If necessary, a
All products should be stored indoors, out of direct 15% caustic solution followed by a water rinse can be
sunlight, under room temperature conditions unless used to further clean containers. All wash and rinse
noted on the MSDS. Products should be stored away solutions must be disposed of in accordance with
from incompatible materials such as oxidizers and federal, state and local regulations.
acids and away from heat, sparks, open flame and
other ignition sources. Contamination with foreign Properly inhibited monomers, oligomers, metallic
materials, such as iron or copper must be avoided coagents, amine acrylates, and M-Cure products are
particularly when working with monomers and generally not RCRA hazardous wastes. In addition,
oligomers. Contact with moisture should also be pelletized styrene-maleic anhydride products and
prevented. polybutadiene products are generally not RCRA
hazardous wastes. However, it is the responsibility of
30
the waste generator to determine if the product meets A few Sartomer products are considered RCRA
the criteria of a hazardous waste at the time of disposal hazardous wastes. For these materials, the waste
(see 40 CFR 261). Disposal options for these classification is listed on the product’s MSDS. Refer
products include landfilling solids at permitted sites, to the MSDS for a product to determine its waste
fuel blending or incinerating liquids. Disposal must classification. Contact Sartomer if you need additional
comply with federal, state and local regulations. Metal information.
recovery should be considered for metallic coagents.
31
Sales Offices
Sartomer Company, Inc.
Oaklands Corporate Center
502 Thomas Jones Way
Exton, PA 19341
Tel: 610-363-4100
Fax: 610-363-4140
E-mail: contact@sartomer.com
Cust. Serv.: 800-SARTOMER
Web: www.sartomer.com
For updated contact information world wide, please refer to Sartomer's web-site at:
http://www.sartomer.com/sales.asp
The information in this bulletin is believed to be accurate, but all recommendations are made without warranty since the conditions of use are beyond SARTOMER Company's
control. The listed properties are illustrative only, and not product specifications. SARTOMER Company disclaims any liability in connection with the use of the information,
and does not warrant against infringement by reason of the use of its products in combination with other material or in any process.
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