Sartomer Products
For Urethane Elastomers
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TABLE OF CONTENTS
INTRODUCTION.............................................................................................................4
POLY BD® RESIN PHYSICAL PROPERTIES..................................................................5
URETHANE CHEMISTRY- ONE STEP URETHANE REACTIONS
AND TWO STEP URETHANE AND UREA-URETHANE REACTIONS........................9
APPLICATIONS FOR POLY BD® RESIN SYSTEMS.....................................................17
APPENDIX A - CALCULATIONS FOR POLY BD URETHANE SYSTEMS..................18
APPENDIX B - PREPARATION OF ELASTOMERS......................................................19
APPENDIX C- PREPARATION OF PREPOLYMERS.....................................................20
APPENDIX D - PRODUCT IDENTIFICATION...............................................................21
APPENDIX E - PHYSICAL PROPERTIES TESTED........................................................21
INTRODUCTION
p oly bd Resins are liquid, hydroxyl-terminated homopolymers of butadiene. Through the use of an isocyanate
®
cure reaction to produce novel urethane products, they offer a route to castable, general-purpose elastomers.
They can be reinforced with various fillers, and extended with a variety of low cost process oils.
The unique structure of the Poly bd® Resins provides properties which surpass both conventional polyether and
polyester urethane systems, as well as conventional, general-purpose rubbers. These novel Poly bd® Resins can be
used in preparing castable elastomers, caulks, sealants, membranes, sponges, foams, adhesives, coatings, propellant
binders, potting and encapsulating compounds, as well as other rubber-fabricated materials.
Some of the outstanding features of Poly bd® urethane systems include:
1) The easy reaction of Poly bd® Resins with curing agents such as conventional di- and polyisocyanates provides
an economical liquid or semi-solid route to general purpose rubbery elastomers.
2) The molecular structure of Poly bd® liquid polymers resembles that of polybutadiene rubber, hence these
polymers can be reinforced with carbon black and other fillers in a similar manner.
3) Oil extendability is another outstanding feature of Poly bd® Resins. Poly bd® liquid Resins are compatible with
a wide variety of hydrocarbon oils and resins. Oil extension, therefore, provides formulation flexibility in
controlling properties of the uncured liquid systems such as pot life and gel time, as well as the properties of the
cured products; such as tensile and tear strengths and elongation.
Oil extension, in combination with filler reinforcement, provides unique formulation flexibility for preparing low
cost urethane products.
4) Improved low-temperature properties are also a feature. Many elastomeric products derived from Poly bd®
Resins have brittle points as low as -70°C.
5) Poly bd® resins have excellent hydrolytic stability. The hydrophobic backbone of Poly bd® Resins imparts
excellent hydrolytic stability to urethane products. Thus, elastomers, caulks, sealants, foams and other products
can be made which are resistant to hydrolysis, even in boiling water.
6) Excellent electrical insulation properties also result from the use of Poly bd® Resins. A discussion of the
benefits of Poly bd® Resins in electrical applications is found in a separate electrical applications bulletin.
7) Chemical resistance is imparted. Poly bd® Resins can be used to prepare polyurethane elastomers with excellent
resistance to aqueous inorganic acids and bases.
With these features, as well as others to be described, Poly bd® urethane systems combine the advantages of
general-purpose rubbers and urethane elastomers within the same polymer network.
4
Physical Properties of Poly bd® Resins
Low Temperature Behavior of Poly bd® Resin
Typical physical properties of two Poly bd® Resins
Based Urethanes
are summarized in Table 1. Their simplified structure
Polyurethane elastomers based on Poly bd® Resins
is represented in Figure 1. The polybutadiene
exhibit outstanding low temperature properties. This
microstructure of both homopolymers is analogous
characteristic is attributable to the “rubbery�
to that of diene polymers prepared by emulsion
polybutadiene backbone. Many polyurethane
techniques. In addition, these polymers possess
elastomers derived from Poly bd® Resins have brittle
predominantly primary, terminal hydroxyl groups of
points as low as -70 °C.
the allylic type. This structural combination accounts
for their high reactivity, especially with aromatic
To demonstrate this characteristic, the physical
diisocyanates. The hydroxyl functionality of Poly bd®
properties of a Poly bd® Resin prepolymer system
R-45M Resin is typically in the range of 2.2 to 2.4
prepared from a 15% free NCO Poly bd® R-45HTLO/
per chain, whereas that of Poly bd® R-45HTLO Resin
TDI prepolymer chain extended with equal
is somewhat higher, typically 2.4 to 2.6 per chain.
equivalents of Voranol 220-530 and Pluracol TP � 340
were measured over a temperature range of -30 ° to
Storage stability for both resins is excellent in the
+ 60 °C. Table 2 shows a nearly constant elongation
absence of air, and their low moisture content allows
over this temperature range, while other properties
them to be used directly from containers without further
behaved consistantly with usual polyurethane systems.
pretreatment in many systems. The typical viscosity-
An elongation of 130% at -30 °C demonstrates that
temperature relationship is given in Figure 2.
the Poly bd® based polyurethane elastomer is not brittle
and, indeed, still possesses elastomeric properties at
Figure 1: Poly bd® Resin Structure
this temperature.
®
Figure 2: Poly bd R-45HT LO Resin
Resin
OH
HO
Viscosity as a Function of Temperature
0.2 50
0.6 0.2
13 TEMPERATRUE VISCOSITY
12 C F mpa s
o o
-12.2 10 140,000
11
Table 1 Typical Properties of Poly bd® Resins
Broodfield Viscosity
-6.7 20 83000
10
Brookfield Viscosity
- 1.1 30 48000
9 4.4 40 32000
Poly bd® Resin
(mpa s x 10 )
R-45HTLO R-45M 8 10 50 24000
-4
15.6 60 14000
Nonvolatile Material, Wt. % 99.9 99.9 7 21.1 70 8800
Viscosity, mPa•s@ 30 oC 6
5000 4300 25 77 6500
5 30 86 5000
Hydroxyl Value, meq/g 0.86 0.73
4 36.1 97 3500
Hydroxyl Number, mg KOH/g 48.2 41 47.2 117 2000
3
Molecular Weight, No. Average 2800 2800 58.3 137 1200
2 69.4 157 800
Water, Wt% 0.03 0.03 1 80.6 177 500
Specific Gravity @ 30oC 0.901 0.899 0
Iodine Number, g/100g 400 400 -1
Polybutadiene Microstructure -10 0 10 20 30 40 50 60 70 80
cis - 20% o
Temperature ( C)
trans- 60%
vinyl- 20%
5
Retention of flexibility at low temperature is a prominent Hydrolytic Stability
feature of Poly bd® Resin based systems. This feature The hydrocarbon backbone in Poly bd® Resin imparts
allows for encapsulation of fragile electrical hydrolytic stability to the finished product, surpassing
components in a medium that retains cushioning that of any other type of polyurethane. Electrical
properties. Embedment stress at - 40°C is significantly insulation properties are maintained in the presence
lower than many competitive materials. This same of moisture, even at high temperatures. Poly bd® Resin
characteristic of the Poly bd® Resin also imparts systems far exceed the 28 day requirement of the Naval
excellent thermal cycling properties to components Avionics test. By measuring hardness vs. time at 100
potted or encapsulated with a Poly bd® Resin based °C and 95% relative humidity, it can be shown that
system. Figure 3 shows the elongation of the Poly Poly bd® based systems are essentially unaffected by
bd® polyurethane described in Table 2 to be essentially moisture at high temperature, whereas other typical
constant over a wide temperature range. urethanes actually liquify (revert) during the test period,
as shown in Figure 4.
Table 2 Elongation Over a Temperature Range
from -30o to 60 oC Hydrolytic Stability of Poly bd® Resins in
Combination with Polyether Polyols
Modulus (psi)
Polyurethane elastomers based on Poly bd® Resins
Temp., Tensile Elongation
exhibit outstanding hydrolytic stability. Again this
50% 100% Tear
o
C (psi) (%)
characteristic is inherent in the nature of the
60 2060 117 960 1775 --
hydrocarbon polybutadiene backbone of the Poly bd®
RT 3250 122 1748 2800 275
Resin. There are no ester or ether linkages to hydrolyze.
-15 5090 125 2800 4390 --
-30 6080 130 3500 5250 423
The addition of even moderate amounts of Poly bd®
Resins to polyether based polyurethanes markedly
Figure 3: Elongation vs. Temperature
improves the hydrolytic stability of the cured
elastomer. Figures 5, 6 and 7 show the test results on
140
two comparable elastomer systems. One contains 24.4
Elongation, %
120
weight percent Poly bd® Resin, whereas the other is
100
based only on the polyether polyol with no Poly bd®
80
Resin.
60
-30 -10 10 30 50 70
Temperature, oC
Figure 4: Comparative Hydrolytic Stability of Conventional vs. Polybutadiene Polyol Urethanes
Polybutadiene Polyol Urethane
.
Shore A - 2 Hardness (25oC)
80 Polyester urethane
60 Polycaprolactone
40 Polyether urethane
20 Polyether urethane
0 Polybutadiene polyol urethane
0 10 20 30 40 50 60
Polyester urethane
Exposure in Days at 100 oC, 95%RH
Ref: Gahimer, F. H., and Nieska, “Navy Investigates Reversion Phenomena of Two Ellastomers,� Insulation, August (1968), p 39 - 44
6
o
Figure 5: Hydrolytic Stability @ 75 C % Test specimens were immersed in water at 75 °C for
Change in Tensile Strength the period shown. Elastomers containing Poly bd®
40
30 Resin had excellent retention of all physical properties
% Change in Tensile
20
after 75 days. Note that hardness and tensile strength
10
are virtually unchanged after 50 days immersion.
Strength
0
-10
Chemical Resistance
-20
Poly bd® Resins can be used to prepare polyurethane
-30
-40 elastomers with excellent resistance to aqueous
-50
inorganic acids and bases. This characteristic is also
-60
attributable to the hydrophobic nature of the
0 10 20 30 40 50 60 70 80
polybutadiene backbone.
o
Days @ 75 C
To demonstrate this resistance, an elastomer prepared
Poly bd Polyether polyurethane
from a 9% free NCO Poly bd® R-45HTLO/TDI
Polyether Polyurethane
prepolymer cured with 2-ethyl-1, 3-hexanediol was
immersed in the test media shown for one week at
o
50 Figure 6: Hydrolic Stability @ 75 C
71°C. The results are summarized in Table 3. The
% Change in Hardness
40
physical properties showed minimal change after
30
exposure. Note also that there was no significant
20
dimensional or weight change.
% Change in Hardness
10
0
These data indicate that Poly bd® Resin can be used
-10
to formulate chemically resistant urethane elastomers.
-20
Physical properties of the elastomer can be varied by
-30
techniques discussed later in this bulletin. The added
-40
chemical resistance obtained from the hydrocarbon
-50
Poly bd® polymer will vary of course, depending upon
0 10 20 30 40 50 60 70
the concentration in a given formulation.
o
Days @ 75 C
Poly bd Polyether Polyurethane
Low Exotherm/ Ambient Temperature Cure
Polyether Polyurethane Poly bd® Resin based systems can be cured at ambient
temperatures by reaction with di- or polyisocyanates.
Pot life/cure time can be readily adjusted by using
o
Figure 7: Hydrolic Stability @ 75 C
typical urethane catalysts. Even when employing
% Change in Elongation
50
catalysts to increase reaction rates, exotherms are low,
% Change In Elongation .
40
usually in the range of 15 ° to 40 °C (300-g mass).
30
20
Minimal Shrinkage
10
Poly bd® Systems cured at ambient temperature exhibit
0
little or no shrinkage.
-10
-20
-30 Toxicity
-40
Poly bd® Resins are high molecular weight polymers
-50
and, therefore, are not expected to pose significant
0 10 20 30 40 50 60 70 80
toxicity/health risks during handling and use. However,
o
Days @ 75 C appropriate protective equipment and good personal
Poly bd/Polyether Polyurethane hygiene should be employed as with any chemical.
Polyether Polyurethane
7
Table 3: Chemical Resistance of Poly bd® Resin Based Urethanes
U ntreated 20% H 2 SO 4 20% N aO H
T ensile Strength, psi 1450 1420 1470
E longatio n, % 315 335 335
M odulus, psi
100% 775 765 770
200% 1020 1010 1020
300% 1340 1280 1350
T ear Strength, pli 224 227 228
H ardness, S hore A 89 89 89
D im ensio nal change, % -- + 0.1 0 + 0.40
W eight C hange, % -- + 0.1 8 0
Refer to MSDS for each Poly bd® resin before Formulating Flexibility
handling. Unlike preformulated potting and encapsulating
compounds, Poly bd® Resins provide fabricators or
For typical applications, low vapor pressure formulators a wide degree of flexibility to develop
polymeric isocyanates are recommended. Toxicity and products suitable for their particular needs. Desired
proper handling information on this component of the physical properties can be achieved by formulating
formulation can be obtained from the manufacturer. with short chain diols, fillers and extenders.
Material Safety Data Sheets should be obtained
from each manufacturer for all ingredients prior to
formulation.
8
Urethane Chemistry- One Step Urethane Reactions and
Two Step Urethane and Urea - Urethane
Poly bd® formulations can be divided into two Procedure for Reacting Poly bd® Liquid
categories � one-step urethanes and two-step Polymers with Isocyanates
urethanes. One-step systems are based upon the direct When producing simple, unfilled elastomers from
reaction of Poly bd® Resin with an isocyanate. The Poly bd® Resins and isocyanates, the liquid polymer
one-step systems offer the advantages of versatility, and the isocyanate are blended with good mixing. The
simplicity, and low cost fabrication techniques for mixture is poured into a mold or applied to a substrate
preparing urethanes having a wide range of physical and permitted to cure at ambient or elevated
properties. Such applications as caulks, sealants, temperature. To prepare castings which are bubble-
elastomers and foams are possible via these systems. free, vacuum degassing is recommended. Refer to
appendices for additional details concerning
Two-step Poly bd® Resin systems are based upon the calculations and procedures.
intermediate formulation of a prepolymer which can
be further chain-extended and crosslinked with Table 4 shows typical properties of unfilled gumstocks
additional diols and diamines to form the final prepared by reacting Poly bd® Resins with commercial
polyurethane. These systems usually provide higher isocyanates. The use of NCO/OH ratios lower than
performance urethanes and have the advantages of unity results in softer, lower modulus materials. At
lowering the overall toxicity of the system. Again, a NCO/OH ratio levels above 1.0 lower modulus
variety of products are possible. material my also be prepared. However, these materials
will gradually increase in hardness with time since the
One -Step Urethane Reactions free NCO groups can undergo further reaction with
Poly bd® liquid polymers offer distinct advantages in moisture to give urea structures, or can form allophanate
preparing one-step urethane products. The primary, crosslinks (especially at elevated temperatures).
allylic nature of the hydroxyl groups, combined with
their controlled functionality (hydroxyl functionality The properties of the unfilled urethanes in Table 4
estimated between 2.2 � 2.6 per chain depending upon resemble those of unreinforced SBR vulcanizate.
particular Poly bd® Resin grade) enables products to Whereas the tensile and tear strengths are low, the
be rapidly and completely cured at ambient or elevated gumstocks show good compression set, impact
temperatures. The cure reaction of Poly bd® Resin resilience and low temperature properties.
with 4, 4� methylenebis (phenyl isocyanate) is illustrated
in Figure 8.
Figure 8: One-Step Urethane Elastomers
H
NCO
C
OH CH2 CH CH CH2 OH + OCN
H
O H O
O(CH2 CH CH Ch2)n O C NH C NH C
X
H
9
Table 4: Properties of Typical One-Step Unfilled must be masterbatched into conventional elastomers
Urethanes Based on Poly bd® Resin with the aid of high-shear mixers for efficient
dispersion, they may be dispersed readily into liquid
Formulation (pbw) 1 2 Poly bd® Resins before curing with minimum energy
Poly bd® R-45HTLO resin 100 100
requirements. Thus, new lower cost fabrication
Toluene diisocyanate 70 - techniques are now offered to rubber goods
Isonate 143L - 12.5
manufacturers.
DBTDL 0.2 0.2
Physical Properties of Gumstocks
The properties of representative carbon black
Tensile Strength, psi 140 179
reinforced elastomers are shown in Table 5
Ultimate Elongation, % 120 101
(Formulations 1 and 2). Comparison of these data
Modulus, psi, 100% 90 179
Tensile Set, % 0 -- with those of Table 5 illustrates that tenfold increases
Hardness, Shore A 45 53 in tensile strengths are obtainable along with general
Tear Strength, pli 20 16
increases in elongation and other strength properties.
Compression Set, %
Method B, 22hrs. @ 158oF 5.5 --
A three roll mill was used to prepare the dispersions
Compression Set, %
in Table 5. The use of high shear compounding
Method B, 22hrs. @ 212oF 30 --
equipment, such as Hochmeier or Cowles mixers,
Impact Resilience Goodyear
results in the lowering of values at least 50%.
Haealey Rebound, % 71 --
Low Temperature Passed-F Passed
Brittleness (B) at -70oC Calcium Carbonate
Calcium carbonate is used quite extensively to extend
Chemical Resistance - Volume Change, +%
10% NaOH, 72hrs. @ 216oF 4.4 -- general-purpose elastomers. Common designations
o
10% HCL, 72 hrs. @ 216 F 3 -- for calcium carbonates include limestone, chalk,
whiting and ground oyster shell.
Unfilled urethane systems may be cured at ambient In general, calcium carbonates are quite soft and may
temperatures, but cure times can be up to 24 hours be used at rather high levels. In fact, addition of
when no catalyst is used. However, using either typical calcium carbonate enhances the extrusion properties
urethane catalysts and /or elevated temperatures, cure of general purpose goods. Elastomers prepared using
rates are greatly accelerated. Catalysts such as this filler are suitable for many caulk and sealant
dibutyltin dilaurate and 1, 4-diazo [2.2.2] bicyclooctane applications where high elongation and moderate tensile
have been used successfully with these systems. properties are required.
Catalyst concentrations are usually in the range of
0.05-0.5 weight %, depending upon the particular Various levels and types of calcium carbonates were
system. The tin catalysts are recommended for fast
investigated to determine the effects on Poly bd® Resin
cures at ambient temperatures in approximately 12 �
based elastomers. The results of this investigation are
16 hours, at 75 °C. in 8-12 hours, and at 125 °C. in
shown in Table 5, Formulations 3-7.
15-30 minutes.
Silica
Filled, One -Step Urethanes
In general, silicas contribute a greater increase in tensile
Poly bd® Resin based urethanes have a polymer
strength than other non-carbon black fillers. Silicas
structure similar to conventional diene rubbers. Just
also have a profound stiffening effect as indicated by
as those systems respond to carbon black
the increased modulus and hardness and the decrease
reinforcement, Poly bd® Resin based urethane systems
in ultimate elongation and tear strength shown in Table
can be reinforced with various carbon blacks, as well
5, Formulations 8 and 9.
as a variety of other fillers. Although carbon blacks
10
Clay effect of oil extension on the physical properties of
Clays, like calcium carbonates, are low cost, high zinc oxide reinforced Poly bd® Resin based elastomers
bulking fillers widely used in the rubber industry. In is discussed in the last section of this page
general, clays give only a moderate degree of
reinforcement, only fair abrasion resistance but a Combinations of Zinc Oxide and Carbon Black
relatively high stiffening effect. Clays are used as fillers Zinc oxide can be effectively employed as a reinforcing
in stocks requiring hardness and high modules; e.g., filler in conjunction with carbon black. There is a
shoe soles and heels, mats, and floor tiles. progressive increase in tensile, modulus, tear, and
hardness as the carbon black loading is increased.
The use of clays as non-black fillers for Poly bd® Resin However, at a constant carbon black level, increasing
based elastomers has been investigated. Data the concentrations of zinc oxide also increases tensile,
describing the use of clay in Poly bd® based elastomers tear, modulus and hardness until maximum values are
are shown in Table 5, Formulations 10 and 11. reached, after which there is a decrease in overall
physical properties. The abrasion resistance of
Zinc Oxide elastomers filled with combinations of zinc oxide and
In addition to reinforcement, zinc oxide also provides carbon black are generally superior to those filled
resilience and heat conductivity. Its use as a reinforcing using carbon black alone. It is important to note that
filler in general purpose elastomers is rather limited, at a constant carbon black level, increasing the
however, due to high density and cost. concentration of zinc oxide decreases the workable
pot life after the isocyanate component is added; i.e.,
The data in Table 5, Formulations 4 and 12, shows gelation occurs more rapidly.
zinc oxide to have a reinforcing effect on Poly bd®
Resin based elastomers. Increasing the zinc oxide In addition to carbon black, other fillers may be
content improves tensile and tear strength, increases incorporated into Poly bd® Resin urethane systems to
hardness and modulus but decreases elongation. The alter physical properties and reduce costs.
Table 5: Properties of Representative Filled Poly bd® Elastomers
Formulation (pbw) 1 2 3 4 5 6 7 8 9 10 11 12
Poly bd® R-45HTLO Resin 100 100 100 100 100 100 100 100 100 100 100 100
Toluene diisocyanate 7 7 7 7 7 7 7 7 7 7 7 7
DBTDL 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Elftex-5 (HAF-Fluffed) 30
Regal 600 (ISAF-L3) 50
Calcium Carbonate 100
Zinc Oxide 100 150
Calcene (CaCO3) 100
Calcene NC (CaCO3) 50
Calcene CO (CaCO3) 100
Silica Filler 100 50
Clay 50 100
Physical Properties
Tensile Strength, psi 1700 1740 350 510 510 680 560 1800 1100 520 560 770
Elongation, % 570 460 320 420 610 630 700 60 170 280 270 210
Modulus, psi
100% 210 280 240 190 330 210 260 800 310 430 470
200% 420 310 340 460 560 750
300% 777 1030 330 420 450 450 380
Tear Strength, pli 139 179 53 94 128 89 99 52 78 55 72 60
Hardness, Shore A 53 58 55 52 59 55 58 90 76 62 71 71
Note: All Poly bd systems used in thermal cycling conditions in air should contain 1 phr of an antioxidant such as
Rabox46 or Irganox 1076. The antioxidant should be added at a temperature above its melting point.
11
Although the degree of reinforcement using calcium The quantity of oil which can be incorporated into a
carbonate or zinc oxide fillers is not as great as with Poly bd® Resin system is a function of the type of oil
carbon black, the non-black systems can be more and the type of filler, if present. Cured Poly bd® Resin
highly loaded (300phr and higher is feasible), and in systems may be formulated which incorporate in excess
combination with oil extension (see Table 6) can of 100 parts oil per 100 parts Poly bd® Resin and do
provide starting points for a wide variety of low cost not “bleed� oil from the final product.
caulks, sealants, elastomers and foams. In addition, a
wide variety of fillers, including clays and talcs can be Table 6 illustrates the effect of oil extension on a zinc
employed with these systems either alone or in oxide-reinforced Poly bd® Resin system. With the
combination to provide the formulator versatility in addition of up to 50 parts oil, there is a moderate
compounding for specific properties. decrease in tensile strength and modulus, and elongation
is greatly improved while the tear strength is unaffected.
Conclusions No bleeding of oil was noted. This data demonstrates
In most cases, non-carbon black fillers contribute less that the combination of oil extension and filler
reinforcement to Poly bd® Resin based elastomers than reinforcement provides a means to improve overall
carbon black fillers. However, there are several properties of Poly bd® Resin based urethanes while
advantages inherent in using non-black fillers. Some reducing formulation cost.
of the more prominent advantages are:
Oil extension provides many other advantages such
Ease of dispersion as further improvement in hydrolytic stability, control
Lower viscosity build of premix viscosities, gel time, cure time, and the ability
Light color to attain higher filler loading. The use of materials such
High loadings � low cost. as chlorinated waxes and oils also provides fire
retardant properties to the finished product.
Oil Extension
Poly bd® Resins, because of their hydrocarbon The effect of oil extension on gel time is shown in
backbones, are compatible with conventional Figure 9 for an unfilled one-step urethane cured with
hydrocarbon oils, chlorinated oils, asphalts and other Isonate 143L. The addition of 60 parts oil extended
related low cost materials. Such mixture can be cured the gel time in an uncatalyzed reaction from 50 to 110
with conventional diisocyanates to yield oil-extended min. With a tin catalyzed system, the trend to lengthen
elastomers. gel time is maintained. However, the relative effect is
diminished.
Table 6: Effect of Oil-Extension on zinc Oxide
Reinforced Poly bd® Based Elastomers The addition of an electrical grade hydrocarbon oil or
ester plasticizer will serve to extend the formulation by
Formulation (pbw) 1 2 3
a dilution effect. These materials are generally utilized
Poly bd® R-45M resin 100 100 100
to reduce viscosity and lower cost. Increasing levels
NCO:OH 1:1 1:1 1:1
of oil or plasticizer will tend to increase elongation and
DBTDL 0.2 0.1 0
lower tensile and tear strengths. Very high levels of oil
Process Oil (A) 25 50
Zinc Oxide 300 300 300 or plasticizer (up to 80 parts per 20 parts by weight of
Physical Properties polymer) will result in a jelly-like cured material with
Tensile Strength, psi 1030 750 510 minimal physical properties but still retaining electrical
Ultimate Elongation, % 160 240 650
insulation characteristics. The addition of liquid
Modulus, psi
extenders will also extend pot life and cure times.
100% 890 570 220
200% -- 730 330
300% -- -- 370
Tear Strength, pli 93 89 92
Hardness, Shore A 82 73 49
(A) Naphthenic oil, viscosity 120cp @ 100 °F
12
Figure 2: Gel Time vs. Extender Oil
9: A list of generally compatible extenders for Poly bd®
Resin includes:
120
Dioctyl Phthalate
100
Diundecyl Phthalate
(Time to reach 100,000 cps)
Tricresyl Phosphate
80
Gel Time (min)
Chlorinated Paraffin
Aromatic Process Oil
60
Naphthenic Process Oil
40
Alkyl Naphthalenes
Asphalt
20
Coal Tar
Linseed Oil
0
Tung Oil
0 50 100 150
Naphthenic Extender Oil, phr Detergent Alkylate
0.05 phr Dibutyl Tin Dilaurate No Catalyst
Asphalt Extension
In addition to extender oils and fillers common to
rubber processing, asphalt modification provides the
The selection of the extender oil will depend on
basis for formulating many low-cost elastomeric caulks,
compatibility parameters as well as the viscosity and
sealants and coatings. Tables 7 and 8 show the
volatility characteristics desired. Hydrocarbon process
properties of a series of asphalt-extended products
oils of the aromatic and napthenic types are very
prepared by adding a mixture of carbon black, Poly
compatible and can be used at relatively high levels.
bd® R-45HTLO Resin and polymeric, PAPI 901
Process oils that have a high paraffinic component are
(f=2.6) or PAPI 27 (f=2.3), or modified MDI, Isonate
the least compatible.
143L, products to either AC-20 or AC-5 straight run
asphalt. The 1:1 NCO/OH ratio used includes the
Plasticizers are also effective as extenders for Poly bd®
isocyanate equivalency of the asphalt. This data
Resin and they tend to be lower in viscosity than
indicates that, while the tensile strengths of the
process oils. Aromatic ester plasticizers such as dioctyl
elastomers are only moderately affected, the
and diundecyl phthalate as well as triisononyl mellitate
elongations change significantly with the level of asphalt
can be used. Linear esters such as di-tridecyl adipate
and the functionality of the isocyanate.
are also useful.
Table 7 Poly bd® Resin/Asphalt AC - 20 Urethanes
Formulation (pbw) 1 2 3 4 5 6 7 8 9 10
Poly bd® R-45HTLO resin 100 100 100 100 100 100 100 100 100 100
Asphalt AC-20 100 200 300 300 200 200 300 400 100 400
Carbon Black Sterling R 6 9 12 15 6 9 12 15 6 15
DBTDL, drops 2 2 2 2 2 2 2 2 2 2
PAPI 27 13.26 14.73 16.2 17.67 -- -- -- -- -- --
PAPI 901 -- -- -- -- 13.02 14.46 15.91 17.36 -- --
Isonate 143L -- -- -- -- -- -- -- -- 14.21 18.94
Physical Properties
Tensile Strength, psi 189 222 319 226 224 340 354 309 265 256
Elongation, % 183 303 437 413 291 600 720 785 506 >800
Tensile Set, % 4 7 18 13 5 17 17 25 8 56
Modulus, psi
100% 158 132 108 89 158 127 100 80 125 72
200% -- 161 122 107 190 145 106 91 160 81
300% -- -- 169 145 220 164 122 101 185 88
Tear Strength, pli 34 44 46 35 42 54 48 40 54 42
Hardness, Shore A 49 48 50 43 44 49 45 45 41 25
13
noted when short chain diamines or mixed alcohol
Short Chain Reinforcing Diols
diamines are employed as auxiliary reactants with Poly
Physical properties of Poly bd® Resin based
bd® Resin.
elastomers can be improved by the addition of auxiliary
polyols to the formulation. A wide variety of short
The Voranol 220-530 chemically reinforces the cured
chain diols may be employed, however, Voranol 220-
Poly bd® elastomer, increasing hardness and improving
530 (phenyl diisopropanolamine) was found to be most
tensile and tear strengths. Table 9 shows the effect of
effective.
using increasing levels of Voranol 220-530 in a Poly
bd® system. Other effective short chain diols are 2-
The use of a short chain diol in conjunction with the
ethyl-1, 3- hexanediol and bis-hydroxyethyl dimerate.
required additional isocyanate increases the urethane
concentration in the final polymer backbone. This
Isocyanates such as PAPI27, PAPI 901 or others may
combination leads to increased hydrogen bonding
be used with Voranol 220-530 systems, but the
between polymer chains and thus higher strength
Isonate 143L produced elastomers with better
properties in the cured elastomer. The same effect is
physical properties.
Table 8 Poly bd® Resin/Asphalt AC -5 Urethanes
Formulation (pbw) 1 2 3 4 5 6 7 8 9 10
Poly bd® R-45HTLO resin 100 100 100 100 100 100 100 100 100 100
Asphalt AC-5 100 200 300 300 200 200 300 400 100 400
Carbon Black Sterling R 6 9 12 15 6 9 12 15 6 15
DBTDL, drops 2 2 2 2 2 2 2 2 2 2
PAPI 27 13.26 14.73 16.2 17.67 -- -- -- -- -- --
PAPI 901 -- -- -- -- 13.02 14.46 15.91 17.36 -- --
Isonate 143L -- -- -- -- -- -- -- -- 14.21 18.94
Physical Properties
Tensile Strength, psi 174 174 202 219 214 275 292 249 466 230
Elongation, % 170 287 403 570 300 562 688 650 593 930
Tensile Set, % 3 5 11 12 4 11 12 14 9 35
Modulus, psi
100% 140 105 76 59 133 111 79 60 111 56
200% -- 134 97 74 173 128 88 72 142 65
300% -- -- 134 97 207 146 100 90 165 75
Tear Strength, pli 34 33 35 29 207 146 100 90 165 75
Hardness, Shore A 43 41 39 34 42 56 39 34 37 25
Table 9 Effects of Voranol 220-530 Content NCO/OH ratio = 1.05
Formulation (pbw) 1 2 3 4 5 6 7 8
Poly bd® R-45HTLO resin, g 100 100 100 100 100 100 100 100
Voranol 220-530 -- 22.2 4.45 8.89 11.85 17.78 26.67 35.56
DBTDL, drops 4 4 4 4 4 4 4 4
Cyanox 2246, g 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Isonate 143L 12.76 15.45 19.14 25.53 29.78 38.29 51.05 63.81
Equivalent ratio - Poly bd®/Voranol 220-530 -- 4/1 2/1 1/1 3/4 1/2 1/3 1/4
Tensile Strength, psi 179 242 377 902 1192 2021 2695 3476
Tear Strength, pli 16 40 46 114 150 231 308 411
Elongation, % 101 151 195 238 245 300 325 297
Modulus, psi
100% 179 192 124 247 465 1073 1609 2182
200% -- -- 195 382 763 1492 2126 2814
300% -- -- -- -- -- 2010 2641 3784
Hardness, Shore A 53 56 62 75 82 -- -- --
Hardness, Shore D -- -- -- -- -- 43 51 53
14
Oil extension and filler reinforcement can be used in cross-linking occurs in these systems because the
combination with short chain reinforcing diols to allow functionality of the Poly bd® Resins is in excess of two.
maximum property and cost modification. Accordingly, when a diol extender is employed,
crosslinking occurs via urethane and allophanate
Two -Step Urethanes and Urea-Urethanes formation. With diamine extenders, further crosslinking
Previous sections described the preparation of one- is possible through urea and biuret formation.
step urethane and urea-urethane products based on
Poly bd® Resins. In many conventional urethane Two -Step Urethanes
applications, it is desirable or essential to utilize a two- Use of the prepolymer technique to prepare Poly bd®
step reaction sequence, wherein an isocyanate- Resin urethanes provides a method for preparing
terminated prepolymer is first formed and subsequently elastomers having improved physical properties over
converted to a high molecular weight elastomer by unmodified or unreinforced one-step Poly bd® Resin
further reaction with glycols, diamines, or other chain- systems. A wide variety of chain-extending diols can
extending agents. be employed and this choice will affect the cure rate
and the final physical properties of the urethane. Two
Isocyanate prepolymers are widely used to produce particularly good diols for use with Poly bd® Resin
high performance elastomers in castable, millable, and based prepolymers are 2-ethyl 1,3 hexanediol, and
moldable forms. Other applications include foams, and Voranol 220-530. Properties of some typical
one and two component coatings, caulks, and sealants. products are summarized in Tables 10 and 11.
The chemistry of Poly bd® Resin based prepolymer As can be seen from this data, maximum properties
systems is depicted in Figure 10. for both systems in tensile and tear strengths occur at
NCO/OH ratios of near unity. However, as the ratio
Prepolymers of Poly bd® Resins can be prepared with is changed, other properties such as elongation and
excellent storage characteristics when the hardness can be altered. Also, at decreased NCO/
recommended reaction and handling precautions are OH the degree of thermoplasticity of the system
observed. See Appendix C for further detailed increases so that production of thermoplastic or millable
information. gumstock is feasible.
Reaction of isocyanate-terminated prepolymers with Variation of the free NCO content of the prepolymer
diol or diamine extenders produces solid elastomers. provides a further means of changing the physical
In addition to the normal chain extension reaction, properties of the cured gumstocks.
Figure 10: Two-Step Urethanes and Urea-Urethanes
OH (CH2 CH CH CH2)n OH + 2OCN R NCO
O O
NCO R NH CO (CH2 CH CH CH2)nO C NH R NCO
Prepolymer
H2N R NH2
OH R OH
O O
O O
C NH Prepolymer NH C NH R NH
C NH Prepolymer NH COR O
15
Table 10 Two Step Urethane Elastomers From Poly bd® R-45M Resin -TDI Prepolymer and 2-Ethyl-1,
3-Hexandiol
Formulation (pbw) 1 2 3 4 5 6 7 8
Percent Free NCO of 6.39 6.56 6.56 6.56 8.71 8.71 8.71 8.71
prepolymer
Reaction NCO/OH Ratio 0.8 0.9 1 1.1 0.8 0.9 1 1.1
Formulation (pbw)
R-45M Prepolymer 100 100 100 100 100 100 100 100
2-Ethyl-1, 3-hexanediol 13.9 12.6 11.4 10.4 19 16.9 15.2 13.8
DBTDL 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Elastomer Properties
Tensile Strength, psi 310 550 1140 990 340 1300 2270 2200
Tear Strength, pli 55 105 140 145 90 230 215 210
Elongation, % 950+ 635 460 335 1130 615 470 410
Modulus, psi
100% 95 185 365 480 195 555 770 865
200% 110 235 495 665 220 680 1010 1145
300% 125 280 650 890 235 795 1270 1470
Hardness, Shore A 45 58 70 74 45 80 84 88
Table 11 Two Step Urethane Elastomers from Poly bd® R-45M Prepolymers and Voranol 220-530
Formulation (pbw) 1 2 3 4 5 6 7 8
Poly bd® R-45M 100 100 100 100 100 100 100 100
Prepolymer
Tinuvin 327 -- -- -- 1 -- -- -- --
Cyanox 2246, g -- -- -- 1 -- -- -- --
DBTDL Catalyst 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Voranol 220-530 15 21.3 29.6 36 26.7 24 21.3 19.3
NCO/OH ratio 1 1 1 1 0.83 0.94 1.04 1.15
Percent NCO of 6 8.9 11.9 14.5 8.9 8.9 8.9 8.9
Prepolymer
Physical Properties
Tensile Strength, psi 1280 3140 2970 1920 1090 3170 3140 2160
Tear Strength, pli 195 295 340 290 275 345 295 305
Elongation, % 400 495 400 400 705 595 495 575
Modulus, psi
100% 570 1040 1485 1690 805 990 1040 880
200% 765 1340 1950 1650 890 1235 1340 1120
300% 970 1685 2200 1670 910 1475 1685 1310
Hardness, Shore D 34 42 51 50 40 42 42 40
16
Applications For Poly bd Resin Systms
Applications for Poly bd® Resin Systems bd® Resin based systems can be mechanically frothed
A wide range of properties is attainable for Poly bd® to obtain medium density, closed cell, flexible and non-
Resin based urethanes. These features, combined with flexible products.
their versatility in formulating with compatible oils and
inexpensive fillers, enhance their value for many Potting and encapsulating compounds exhibit excellent
elastomer applications. General-purpose rubber parts electrical properties. Further information on the
can be easily and inexpensively processed from Poly electrical properties of these materials is available on
bd® Resin based formulations. These products can request.
vary from completely castable liquids to millable
gumstocks. Oil and asphalt-extended Poly bd® Resin The ability of Poly bd® Resins to accept high filler
based systems permit the manufacture of low-cost loadings and to be extended with asphalts and oils
systems for elastomer coatings, linings, adhesives, allows the formulation of many low-cost, good
caulks and sealants. performance caulks and sealants.
Compounding flexibility permits viscosity control for A list of applications where Poly bd® urethane
sprayable coatings and adhesives, with excellent elastomers are typically used includes:
moisture and chemical resistance. Other advantages
of Poly bd® Resin based 100% polymer systems over Electrical/Electronic Potting & Encapsulation
many conventional systems include the elimination of Construction
the use of solvents and solvent removal equipment and Asphalt Extended Membranes
capability for room temperature cures or very fast oven Waterproofing Membranes
cures. The liquid Poly bd® Resin prepolymer systems, Roofing
cured with Voranol 220-530, provide excellent high Mastics
performance coatings having good abrasion, impact Highway Sealants
and low temperature ductility properties. Architectural Sealants
Insulating Glass Sealants
Both rigid and flexible products can be produced by Adhesives
chemical blowing techniques identical to those used in Rubber Parts
foaming polyether and polyester urethanes. Foamed Military/Aerospace
products can be produced with blowing techniques Automotive
used in sponge rubber production. In addition, Poly Encapsulants
Sealants
17
Appendix A active H will react with one equivalent of NCO. In
In all urethane calculations the reactants should be general, an NCO/OH equivalent ratio of approximately
expressed in terms of equivalent weight. The basis for 1 will provide the best physical properties. The
this approach is that one equivalent of OH or other following relationships for equivalent weight (EW) will
be helpful in urethane calculations.
Molecular Weight
For Hydroxyl : EW = Functionality
Compounds 56100
EW = Hydroxyl Number
1000
MW of NCO Compound
EW =
Hydroxyl Value
For Isocyanate : EW = Functionality
1700
EW = Compounds
%Hydroxyl
4200
EW =
milliequivalent OH
Also: Hydroxyl Value = %NCO in compound
g
= Hydroxyl Number
56.1
Examples of Urethane Formulation Stoichiometry follow:
General Formula
Weight NCO Compound (Hydroxyl Value) (EW NCO compound) (NCO/OH ratio)
=
100 g Hydroxyl Compound 10
1. Find the weight of Isonate 143L (EW = 143) needed to prepare a gumstock from Poly bd R- 45HTLO Resin
(Hydroxyl Value = 0.83 meq/g) at an NCO/OH ratio of 1.1.
Weight Isonate 143L
= (0.83) (143) (1.1) = 13.0g
100g Poly bd R-45HTLO Resin 10
For each 100g of R-45HTLO Resin, 13.0g of Isonate 143L would be required.
2. Find the weight of Isonate 143L needed to make a Poly bd Resin system reinforced with
Voranol 220-530, at a Poly bd/Isonol equivalent of 0.5 and NCO/OH ratio of 1.1.
Weight Poly bd R-45HTLO Resin
Equivalents Poly bd R-45HTLO Resin =
EW Poly bd R-45HTLO Resin
100g
= = 0083 equivalents
1000/0.83 meq/g
Equivalents Voranol 220-530 = (2) (equivalents Poly bd R-45HTLO Resin) = (2) (0.083 eq)
= 0.166 equivalents
Weight Voranol 220-530 = (Equivalents Voranol 220-530) (EW Voranol 220-530)
= (0.166eq) (104.5g/eq) = 17.3g
Weight Isonate = (total OH equivalents) (EW Isonate 143L) (NCO/OH)
143L required = (0.083g + 0.166g ) (143 eq/g) (1.1) = 39.2g
Formula would be:
Poly bd R-45HTLO Resin 100g
Voranol 220-530 17.3g
Isonate 143L 39.2g
3. Prepolymers of Poly bd® Resins may be prepared at various % free NCO by use of the following equation:
weight isocyanate 100 (EW Isocyanate) 100(EW NCO) + (EW Poly bd Resin) (% Free NCO)
100g Poly bd Resin = X 100 (EW NCO) - (EW Isocyanate) (% Free NCO)
EW Poly bd Resin
18
Appendix B � Preparation of Elastomers Catalyst concentration and /or level of oil extension
permit wide latitude in pot lives and cure times of
1. One � Step Urethanes specific formulations as previously discussed.
A. Weigh out the components of the desired Moreover, the type of filler greatly affects workable
formulation; e.g., Poly bd® Resin, filler(s), pot life and cure time. For example, zinc oxide
extender oil, anti-oxidants, and catalyst. catalyzes the reaction and, therefore, shortens pot
life. But acids fillers such as silicas may have a
B. Charge the weighed components to a suitable retarding effect on pot life and ultimate cure time.
mixing device and mix until the ingredients are well
dispersed. Mixing time may vary with the efficiency 2. One –Step Urea- Urethanes
of the mixing device.
Procedure is identical as for the one –step urethanes,
It is advisable to degas the “masterbatch� during except that diamines are added to the Poly bd® Resin
the mixing steps under vacuum. It may also be formulation durning the initial mixing cycle.
necessary to dry fillers at elevated temperatures
to remove moisture. 3. Two � Step Urethanes
C. Add the calculated amount (See Appendix A) of The weighed prepolymer is mixed with weighed
di- or polyisocyanate to the mixture to give the amounts of catalyst, filler and polyol, such as Voranol
desired NCO/OH ratios between 1.0 and 1.1 220-530, or more Poly bd® Resin (or diamine if urea-
urethanes are desired) and cured at ambient or elevated
D. Mix the completed formulation until homogenous temperature.
and pour or pump into molds or apply to desired
substrate. *Note: A three-roll paint mill was used to prepare the
filled formulations presented in this bulletin. However,
E. If multi-component mixing-metering equipment is experimental work has shown that fillers can be
utilized, the filled Poly bd® Resins and isocyanate satisfactorily dispersed with conventional mixers.
components may be metered separately into the
mixing head of the metering device.
F. Permit the formulation to cure, Longer cure times
are required at lower temperatures. The
elastomers described in this bulletin were arbitrarily
cured at 80 � 100 oC for 1.5 hours unless
otherwise stated. No differences in properties
were noted between elastomers which were cured
at ambient or elevated temperatures.
19
Appendix C � Preparation of Prepolymers Procedure
Prepolymers from Poly bd® Resins can be prepared The Poly bd® Resin was charged to the autoclave,
with excellent shelf � life when the following reaction and the autoclave sealed. The agitator was turned on,
and storage precautions are observed: the vessel evacuated to 20 mm mercury absolute
pressure, and heating begun.
1. The Poly bd® Resin must be thoroughly degassed.
It is recommended that the resin is heated at About two hours time was required to heat the charge
100oC at low vacuum for a minimum of 30 minutes from 20 to 110 oC, with a maximum jacket
with efficient stirring. temperature of about 115 oC. The autoclave internal
pressure was 5 mm mercury absolute pressure at the
2. The addition of benzoyl chloride (0.03% based 110 oC internal temperature. The autoclave contents
on Poly bd® Resin) prior to the addition of the were degassed and sirred at 110 oC and 5 mm mercury
diisocyanate greatly enhances the stability of the absolute pressure for thirty minutes. The autoclave
preoplymer product. The same amount of benzoyl contents were then cooled to 40 oC over a two-hour
chloride may be added to the prepolymer at the period.
completion of the reaction to further insure shelf
stability. The autoclave internal pressure was increased to 55
mm mercury absolute pressure and benzoyl chloride
3. When storing the prepolymer, containers with added.
plastic lids should be avoided. Narrow-mouthed
solvent cans which can be plugged and then After stirring five minutes, the diisocyanate was
capped are the most satisfactory containers. The added. The addition required about three minutes. The
product should always be purged with nitrogen exothermic reaction increased the internal temerature
before sealing. from 40 oC to 50 oC over a twelve-minute time interval.
The procedure below has been employed successfully The autoclave contents were then heated to 60 oC
in preparing Poly bd® prepolymers. The equipment with stirring, at 50 mm mercury absolute pressure, over
used was a five- gallon 316 stainless steel jacketed a one hour period.
autoclave equipped with an anchor type stirrer,
thermowell, charging port, vacuum and nitrogen lines, The reactor contents were maintained at 60 oC/ 50
and a bottom flush valve. The autoclave was heated mm mercury, with stirring for two hours.
by circulating a lubricating oil heat transfer fluid
through a 6 kW electric heater and then through the A second portion of benzoyl chloride was then added
autoclave jacket. Cooling was effected by circulating with stirring, and the product withdrawn into three
the oil through a water cooled heat exchanger and two–gallon screw-top cans. The cans were thoroughly
through the autoclave jacket. flushed with purified nitrogen before sealing.
For low NCO pre-polymers (6% Free NCO) it is
recommended that 1% Ralex 46 also be added for
package stability.
20
Appendix D
Tradename Chemical Name Supplier
Voranol 220 - 530 (phenl diisopropanolamine) The Dow Chemical Company
Isonate 2143L Polyfunctional liquid isocyanate The Dow Chemical Company
PAPI Polymethylene polyphenyl isocyanate The Dow Chemical Company
Ralox 46 Antioxidant Raschiq Industries
Tinuvin 327 U.V. Stabilizer Ciba Corporation
Lead Octoate Catalyst Nudex Chemical Company
DBTDL Catalyst Dibutyltin Dilaurate Atofina Chemicals
Dabco Triethylene Diamine Air Products & Chemicals, Inc.
Pluracol TP - 340 Urethane Triol BASF Corporation
Appendix E
The following testss were used to determine properties of Poly bd® elastomers described in this brochure.
Physical Propertiy Tested Method
Tensile Strength ASTM D - 412 - 61T
Ulimate Elongation ASTM D - 412 - 61T
Tensile Modulus ASTM D - 412 - 61T
Tear Strength ASTM D - 642 - 51 (Die C)
Shore Hardness ASTM D - 676 - 59T
Flexural Cut Growth Resistance ASTM D - 1052 - 55
Low Temperature Brittleness ASTM D - 746
Compression Set ASTM D - 395
Oil and Solvent Resistance ASTM D - 471 - 64T
Abrasion Index ASTM D - 1630 - 61T
Impact Resilence ASTM D - 1054 -55
21
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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.
1560 08/05
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