Sartomer Products

For the Rubber and

Cable Industry

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 TABLE OF CONTENTS

Liquid polybutadienes KRASOL® - General information........................................................... 3

Characteristics of KRASOL® Grades for Rubber and Cable Industry...................................... 4
KRASOL® LB....................................................................................................................................4
KRASOL® PS-01............................................................................................................................... 4
Application of KRASOL® polybutadienes in rubber and cable compounds..............................5
Coagents in peroxidic cure of EPM and EPDM elastomers...............................................................5
Processing aid in rubber compounds..................................................................................................5
Effects of the application KRASOL® polybutadienes on the compounds and vulcanizate
properties...........................................................................................................................................6
Appendix............................................................................................................................................6
Examples of KRASOL® applications in EPM/EPDM compounds....................................................7
Cable jacketing compounds (Tables 3, 4, 5).......................................................................................7-10
Compounds for industrial applications:
construction profiles, rubber packing, membranes (Table 6).............................................................11-12
Compound for hard sealing profiles (Table 7)....................................................................................13
Examples of KRASOL® applications in rubber compounds..............................................................14
Tire compounds - sidewalls, treads, retreading compounds (Tables 8, 9)..........................................15
Rubber foam compounds - Shoe soles (Table 10)..............................................................................16
Compound for rubber-metal parts......................................................................................................17
 Liquid polybutadienes KRASOL® - General information

KRASOL ® polybutadienes are liquid low- terminal groups or of double bonds. The
molecular weight polymers of butadiene with outstanding features of liquid polybutadienes are
varied compositions. Chemically, they are either their easy handling and processing, high reactivity,
functionalized, i.e. contain terminal reactive special properties of crosslinked products and a
functional groups, or nonfunctionalized, i.e. great variety of possible applications.
without terminal reactive groups. Two basic types
are polybutadienes with terminal hydroxyl groups, Low molecular weight polybutadienes have been
KRASOL ® LBH, and nonfunctional poly- used for decades in rubber industry as special
butadienes, KRASOL® LB. Each of these two basic additives that can substantially affect the
types is available commercially in three molecular vulcanization process, as well as the properties of
weights: 2000, 3000 and 5000 g/mol. both the rubber compound and the vulcanizate.
They are used widely in compounds for cables,
Anionic polymerization technology that is used for where they act as coagents of peroxidic
the manufacture of KRASOL ® polybutadienes vulcanization in the electrical insulating
produces well defined linear polymeric products compounds based on EPM/EPDM elastomers.
with a specific microstructure and very narrow
molecular weight distribution. The relatively high The basic KRASOL® polybutadiene grade designed
vinyl double bonds content is significant for the for the use in rubber industry is KRASOL® LB. It
chemical reactivity, processing properties and the is a low molecular weight polybutadiene with about
properties of final products. 65 % vinyl (1,2-) structure, available in various
molecular weights. A dry liquid form of this grade
The KRASOL® liquid polybutadienes are colorless - liquid KRASOL® LB on dry powder silica carrier
viscous liquids of oil-like consistency at ambient – is manufactured and distributed as KRASOL®
temperatures. Solid elastomeric materials are PS-01. This form offers convenience in handling,
produced from them by chemical reactions of weighing, dispersibility and clean-up.

3
 Characteristics of KRASOL® Grades for Rubber and Cable Industry

KRASOL® LB KRASOL ® LB low molecular weight poly-

KRASOL® LB grades are polymers of butadiene butadienes can be utilized in rubber industry in
without terminal functional groups. Their chemical several different functions, based either on their
structure can be expressed by a simplified formula: physical nature or their chemical reactivity.

H - (- CH2 - CH = CH - CH2 -)n - H KRASOL® LB grades are used largely as effective

coagents for peroxide cured EPM and EPDM
At ambient temperatures they are clear viscous rubbers, where they also improve the processing
liquids, miscible with oils, bitumens and most characteristics of the EPM/EPDM compound.
organic solvents. They can be loaded with large
amounts of fillers and oils. Typical properties of KRASOL® LB grades can also be utilized as
KRASOL® LB liquid polybutadiene grades with processing aids in common rubber compounds.
molecular weights 2000, 3000 and 5000 g/mol are Generally, they can lower the viscosity of the
shown in Table 1. compounds and act as covulcanizable plasticizers,
enhancing product properties.

Table 1 Typical properties of KRASOL® LB polybutadiene grades

Parameters KRASOL® LB 2000 KRASOL® LB 3000 KRASO® LB 5000

Molecular weight, Mn (g/mol) 1800-2500 2500-3500 4500-5500
Polydispersity index, Mw/Mn About 1.1
Viscosity Brookfield 25 °C (Pa.s) 4-7 6-10 10-30
85 °C (Pa.s) 0.35-0.45 0.45-0.6 about 1.1
Microstructure 1,4-cis (%) Approx. 18
1,4-trans (%) Approx. 17
1,2- (vinyl) (%) Approx. 65
Water content (% wt.) Max. 0.04
Solids (% wt.) Min. 99.5
Density, 20 °C (g/cm3) Approx. 0.9

KRASOL® PS-01 handling and dosing of liquid polybutadienes. As

KRASOL® PS-01 is a mixture of low molecular a solid alternative of KRASOL® LB in the powder
weight KRASOL® LB 3000 polybutadiene and an dispersion form it is used mostly as a coagent of
active form of silica (silicon dioxide). This powder peroxidic vulcanization of ethylene-propylene
KRASOL ® grade is manufactured to aid the elastomers compounds. Typical properties of the
KRASOL® PS-01 are shown in Table 2.

Table 2 Typical properties of KRASOL® PS-01

Appearance White to grayish powder

Polybutadiene content (% wt.) 56-60
Ash (% wt.) 35-36
Bulk density (g/cm-3) 0.31-0.35

4
 Application of KRASOL® polybutadienes in rubber and cable compounds

Coagents in peroxidic cure of EPM and EPDM/EPM formulations containing KRASOL®

EPDM elastomers LB or KRASOL ® PS-01 as coagents can be
Saturated elastomers, like EPM, cannot be vulcanized in the usual way to yield final products
vulcanized by sulfur, due to a lack of double bonds. with enhanced properties. Simultaneously,
Use of these saturated elastomers requires using KRASOL LB polybutadienes can favorably affect
of peroxide cure agents. As the peroxide the flow properties of the composition.
vulcanization of such polymers is not highly
efficient, various coagents have to be used. Processing aid in rubber compounds
The use of KRASOL® LB grades as processing
In general, commonly utilized coagents are aids in common synthetic and natural rubber
polyfunctional, multi-unsaturated organic com- compounds is based on their liquid, low molecular
pounds which readily form free radicals. There are weight character and the high content of reactive
two groups of coagents: crosslinkable double bonds.

• One of them includes various acrylates, meth- KRASOL® LB polybutadienes can reduce the
acrylates, bismaleinimides and vinyl esters. viscosity of uncured stocks enabling better energy
• The other coagents group includes allylic efficiency and/or higher filler levels in the
compounds and high vinyl polymers. Allylic compound. They can be incorporated as
compounds used are usually cyanurates and nonextractable and nonmigrating plasticizers. Due
isocyanurates such as triallyl cyanurate (TAC) to the vinyl double bonds, they can covulcanize
or triallyl isocyanurate (TAIC). The most with the other rubbers in the compound, increasing
important vinyl polymers used are low the crosslink density of the vulcanizate. Enhanced
molecular weight high 1,2- (vinyl) crosslink density results in improved final
polybutadienes. elastomer properties, such as compression set,
hardness and modulus. The aging resistance of
Polybutadienes have proved to be the most effective vulcanizates is usually not affected, though in some
coagents of peroxidic cure in EPM/EPDM cases it was reported that high vinyl polybutadienes
compounds, increasing their scorch time and could have a favorable influence on the oxidative
crosslink density of the vulcanizates. They can also degradation of vulcanizates and their swelling in
give the products higher water resistance and organic solvents.
better electrical performance.

5
 Effects of the application of KRASOL® polybutadienes
on the compounds and vulcanizate properties

When properly used, KRASOL® polybutadienes • Electrical insulation properties of rubber

can resolve a whole range of specific technological vulcanizates are not negatively affected
problems, occurring in development and (significant in cable and wire jacketing
manufacture of rubber goods. The most frequent compounds)
uses are in peroxidic cure and as plasticizers.
In applications of liquid polybutadienes in rubber
The effects of the addition of KRASOL® LB compounds that are based on the reactivity of vinyl
polybutadienes on the properties of rubber double bonds, it is necessary to take into
compounds and vulcanizates can be summarized consideration the real content of the 1,2- structures
as follows: in a polybutadiene used. In case of KRASOL® LB
the vinyl content is about 65 %, i.e. if a
With increasing polybutadiene amount in a polybutadiene with a higher vinyl content is to be
compound replaced in an application, a proportionate amount
of the polybutadiene with a lower vinyl content
• Processing of the compound is improved as the should be used for attaining the same effect.
viscosity is decreasing
• Flow properties of a compound for extrusion KRASOL ® PS-01 has the same effect on
or injection molding are improved compounds and vulcanizates as KRASOL® LB -
• The power input for the compound mixing is only it is necessary to take into account a lower
lowered, mixing cycle can be shortened and the content of active polybutadiene component in the
compound temperature at the end of the cycle powder dispersion.
can be lower
• Problems with sticking of the compound to the Appendix
metal parts of the processing equipment can In the following part of this Manual, some practical
be eliminated examples of KRASOL® LB and KRASOL® PS-
• Minimum and maximum modulus of the 01 in EPM/EPDM as well as in common rubber
compound are lowered compounds are presented. Further testing of
• Scorch safety is increased, vulcanization rate KRASOL® polybutadienes in rubber and cable
can be higher applications is in progress.
• The polybutadiene double bonds, in particular
vinyl groups, can be incorporated into the Overview of the examples of KRASOL ®
vulcanizate network and increase its crosslink applications:
density. This effect can be utilized in some hard
compounds, where Krasol® in amounts about Examples of KRASOL® applications in
3 phr acts as a plasticizer so that the compound EPM/EPDM compounds
can be processed by extrusion, while after Cable jacketing compounds Tables 3, 4, 5
vulcanization the final hardness remains Compounds for industrial applications:
unchanged (corresponding to the rubber used) construction profiles, rubber packing, membranes
• Permanent set of vulcanizates is lowered Tables 6, 7
• The aging resistance of vulcanizates is not
affected

6
Examples of KRASOL® applications in Rubber foam compounds - Shoe soles Table 10
rubber compounds Compound for rubber-metal parts
Tire compounds - sidewalls, treads, retreading
compounds Tables 8, 9

Examples of KRASOL® applications in EPM/EPDM compounds

Cable jacket compounds (Tables 3, 4, 5)

Test conditions:
Mixing: Calender roll 160 mm x 320 mm, 30 min. 40-50 °C
Vulcanization: 163 °C, 10.3 Mpa, cure time for tests 40 min.,
Ethylene-propylene elastomers and coagents used:

DUTRAL CO 054
Ethylene-propylene copolymer (EPM), propylene content 41%, Unsaturation level: 0,
Mooney viscosity ML (1+4)@125 °C>44, product of EniChem

DUTRAL TER 4044

Ethylene-propylene-diene terpolymer (EPDM), propylene content 35%, Diene: Diene: ENB, Unsaturation level: Medium,
Mooney viscosity ML (1+4)@125°C>44, product of EniChem

SKEP-540D
Ethylene-propylene copolymer (EPM), propylene content 33-40%, Mooney viscosity ML (1+4)@100 °C> 36-45,
product of Neftechim, Nizhnekamsk, Russia

SKEPT-40D
Ethylene-propylene diene terpolymer (EPDM), propylene content 33-40%, Diene: ENB 3.0-5.0%,
Mooney viscosity ML (1+4)@100 °C> 36-45, product of Neftechim, Nizhnekamsk, Russia

Liquid polybutadiene
A commercial liquid polybutadiene, molecular weight (Mn) 1800, 40-50% 1,2-(vinyl) structures

TAC
Triallyl cyanurate (2,4,6-triallyloxy-1,3,5-triazine)

7
Table 3 …Continued

Components Compound No.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Dutral CO 054 100 100
Dutral TER 4044 100 100
SKEP-540D 100
SKEPT-40D 100
Peroximon F-40 7.0
Stearic acid 1.0
Zinc oxide 5.0
Paraffin 4.0
Dusantox 86
(Antioxidant, diphenyl 1.6
amine type)
Kaolin, dehydrated 75.0
Phenylethoxysiloxane 1.5
Chalk natural, treated 26.9 20.9 14.9 26.9 20.9 14.9 26.9 20.9 14.9 26.9 20.9 14.9 20.9 24.9 20.9 24.9
KRASOL® LB-3000 - 6.0 - - 6.0 - - 6.0 - - 6.0 - - - - -
KRASOL® PS-01 - - 12.0 - - 12.0 - - 12.0 - - 12.0 - - - -
Liquid Polybutadiene - - - - - - - - - - - - 6.0 - 6.0 -
TAC - - - - - - - - - - - - - 2.0 - 2.0
Vulcanizate properties
Modulus, M 100 (Mpa) 1.25 1.67 1.95 1.48 1.75 1.91
- 1.29 1.36 1.49 1.90 1.89 1.61 3.01 1.67 3.38
Tensile strength (Mpa) 4.07 3.86 4.07 4.72 4.13 4.10
- 3.62 3.73 4.56 4.66 4.94 3.98 5.30 4.67 5.23
Elongation at break (%) 780 570 462 652 416 428
- 623 584 656 434 405 562 394 490 318
Tension set (%) 77 47 36 50 30 31
- 39 36 54 32 31 44 19 38 14
Properties after aging After 7 days at 135 °C
Tensile strength (%) +7 +13 +6 +15 +28 +100 - +41 +26 +27 +28 +25 +9 +42 +43 +44
Elongation at break (%) +9 -6 -18 -5 +4 +37 - +2 -3 -1 -13 -11 -8 +24 +8 +7
After 15 days at 135 °C
Tensile strength (%) - +35 +40 - +29 +78 - +43 +29 - +64 +52 +34 +62 +35 +43
Elongation at break (%) - -14 -17 - -7 -1 - -2 -8 - -27 -32 -13 +14 -4 -7
After 30 days at 135 °C
Tensile strength (%) - +35 +35 - +35 +93 - - - - +87 +79 +29 +55 +24 +46
Elongation at break (%) - -32 -34 - -23 --6 - - - - -47 -53 -30 -18 -25 -22
Dielectric parameters before and after immersion in water at 20 °C, cured 40 min. at 163 °C
time (days)
Immersion

Parameter

Pv. 10-13 (Ω.m) 1.8 1.7 1.9 1.7 1.9 1.7 - - - 1.7 0.95 0.86 1.7 1./8 1.8 1.7
0 (Original

tg δ. 10-2
sample)

1.2 2.2 2.0 2.1 2.7 1.2 - - - 1.2 3.1 2.5 1.4 0.9 2.8 1.1
ε 2.7 3.0 2.8 2.9 2.7 2.9 - - - 2.7 3.1 3.0 2.8 2.8 3.3 2.9
Es (MV.m-1) 27.5 30.1 32.2 32.1 31.2 28.8 - - - 27.5 37.7 36.3 29.9 29.9 31.1 30.7
1 Pv. 10-13 (Ω.m) 1.8 1.7 1.9 1.7 1.9 1.7 - - - 1.7 1.3 1.7 1.7 1.8 1.8 1.7
tg δ. 10-2 1.2 1.7 1.9 2.0 2.8 1.3 - - - 2.0 2.2 1.7 1.6 0.9 2.8 1.6
ε 2.7 2.9 2.9 2.8 2.8 3.0 - - - 3.0 3.3 3.0 2.9 2.8 2.9 2.9
Es (MV.m-1) 28.5 33.3 31.8 32.0 32.2 30.7 - - - 29.2 25.6 28.7 35.9 33.8 31.2 30.8
14 Pv. 10-13 (Ω.m) 0.93 1.7 1.9 0.58 1.9 1.7 - - - -.75 1.6 1.7 1.7 1.8 1.8 1.7
tg δ. 10-2 1.8 2.5 2.2 2.3 1.9 2.3 - - - 2.3 2.7 1.7 2.3 1.4 2.1 1.7
ε 2.9 2.9 3.0 3.0 2.8 3.2 - - - 3.2 3.2 3.0 3.0 3.0 2.9 3.1
Es (MV.m-1) 29.3 27.9 30.4 30.0 30.5 29.7 - - - 31.6 29.6 29.2 30.4 28.8 30.3 30.9

Pv Volume resistivity, tg ä ...Dielectric loss, ε Permitivity, Es...Electric strength

Conclusions (Table 3) vinyl polybutadiene KRASOL® leads to a desirable

The addition of KRASOL® polybutadienes to EPM increase of the vulcanizate cross-link density. Thus,
or EPDM compounds results in increased modulus, liquid polybutadienes KRASOL® are effective
lower elongation and lower permanent set. These coagents of peroxidic vulcanization of EPM and
effects indicate that the use of low molecular high- EPDM compounds.

8
KRASOL® polybutadienes can be used as coagents the commonly used commercial liquid poly-
either in the basic liquid form (LB Grade) or dry butadienes of similar structure and properties. In
liquid (powder dispersion) form (PS-01 Grade). general, the application of all liquid high vinyl
Their application does not depend on the polybutadienes is less effective in comparison with
technology of EPM/EPDM manufacture or on the the use of triallyl cyanurate (TAC) as a coagent.
kind of the third comonomer in the EPDM used.
Thermal stability and dielectric characteristics of
Physical and mechanical properties of vulcanizates all rubber materials tested, including those with the
show that KRASOL® polybutadiene in both forms use of KRASOL ® polybutadienes, meet the
tested has a vulcanization activity comparable to requirements on insulation rubber materials for
cables and wires.

Table 4 KRASOL® LB in low-medium voltage cable EPM and EPDM compounds. A comparison
with the effect of another commercial liquid polybutadiene.

Compound No.
Components 1 1a 2 2a
Dutral CO 054 100 -
Dutral TER 4028 - 100
Zinc oxide 5 5
Stearic acid 1 1
Whitetex 120 150
Calcium carbonate, Omya BSH - 25
Paraffinc oil 25 40
Anox HB 1.5 1.5
A-172 1.5 1.5
Peroximon DC/40 9.6 9.6
Liquid polybutadiene 6 - 6 -
KRASOL® LB 3000 - 6 - 6
Uncured properties
ML(1+4) @100 °C 33 34 62 62
MDR @180 °C (Gap 2,Arc.2)
t1 (min.) 0.44 0.44 0.44 0.44
t90 (min.) 3.2 3.12 3.16 3.12
ML (Nm) 0.041 0.046 0.078 0.074
MH (Nm) 0.373 0.512 0.628 0.694
Cured properties Cured 30 min. at 165 °C
Tensile strength (Mpa) 6.5 7.5 11.5 12.0
Elongation at break (%) 360 250 280 230
Modulus M200 (Mpa) 4.5 7.0 8.0 10.0
Tension set at 200% (%) 6 6 15 24
Hardness Shore A (3”) 56 60 71 71
Compression set, 70h/100 °C (%) 18 11 12 10
Compression set, 70h/150 °C (%) 20 14 15 13
Aged properties 150 °C, 7 days
Tensile strength (% rtd.) 97 105 105 106
Elongation at break (% rtd.) 102 109 83 89
150 °C, 14 days
Tensile strength (% rtd.) 87 98 85 85
Elongation at break (% rtd.) 88 102 57 60

9
Table 4 ...Continued

Test conditions:
Internal mixing, upside-down (dump at 5 min.) coagents and peroxide added on open mill 5 min./100 °C

Polymers used:

DUTRAL TER 4028

Ethylene-propylene-diene terpolymer (EPDM), propylene content 25%, Diene: ENB, Unsaturation level: Medium,
ML (1+4)@ 125 °C = 44, product of EniChem

DUTRAL CO 054
Ethylene-propylene copolymer (EPM), propylene content 41%, unsaturation level: 0, Mooney viscosity
ML (1+4)@125 °C =44, product of Enichem

Liquid polybutadiene
A commercial liquid polybutadiene widely used as coagent of peroxidic cure in EPM/EPDM compounds.
Molecular weight min. 2600, Molecular weight distribution: broad, Microstructure: 40-50% 1,2- (vinyl), 15-25% 1,4-cis.

Table 5 KRASOL® PS-01 in an EPDM cable compound

Components Amount (phr)

Keltan 778 100
Kaolin, dehydrated 100
Paraffinic – naphthenic oil 10
Paraffin 5
Vinylsilane 1.5
Antioxidant – Chinolinic type 1.5
Stearic acid 1
Zinc oxide 5
Dicumylperoxide 50% 7
KRASOL® PS-01 6
Uncured properties
Mooney viscosity ML(1+4) @ 100 °C 72.5
MH – ML @180 °C (N.m) 73
t90 @180 °C (min.) 3.9
Cured properties Cured 10 min. 1 at 80 °C
M (200%) (Mpa) 8.72
Tensile strength (MPa) 11.86
Elongation at break (%) 315
Hardness Shore A (°Sh) 71
Aged properties 135 °C/7 days
Modulus M 200, Change in % +22
Tensile strength, Change in % +20
Elongation at break, Change in % -4
Hardness Shore A, Change in % +3
Dielectric properties At laboratory temperature
Pv. 10-13 (Ω.m) 11.0
tg δ. 10-2 6.0
ε 2.57
Es (MV.m-1) 26
Dielectric properties Water immersion
Pv. 10-13 (Ω.m) 1.8
tg δ. 10-2 7.59
ε 2.6
Es, (kV.mm-1) 27

10
Test conditions: Laboratory Bridge-Banbury mixer Conclusions (Table 5)
1.5 liter, 110 - 130 °C The addition of KRASOL® PS-01 coagent to an
Mixing procedure: EPDM compound results in improved
0’ rubber processability of the compound (ML 1+4),
2’ 1/2 filler, plasticizers, vinyl silane increased vulcanization rate (t90) and in a higher
5’ 1/2 filler, other components except cure cross-link density of the vulcanized rubber (MH -
system ML).
9’ discharge the compound
KRASOL® PS-01 has no adverse effect on the
Compounds were homogenized on two-roll mill thermooxidation stability of vulcanizates or on the
at ambient temperature and at the same time the electrical insulation characteristics.
vulcanization system was added.
KRASOL® PS-01 in an EPDM compound can
Elastomer used: Keltan 778 - EPDM, Mooney improve permanent set at low and high
viscosity ML (1+4)@125 °C = 63, ENB 4.5 %, temperatures.
product of DSM.

Compounds for industrial applications (Tables 6,7)

Table 6 KRASOL® PS-01 in EPDM compounds for various industrial applications

Compounds No. 1, 2: Construction profiles (High modulus)
Compounds No. 3, 4: Rubber sealing (Medium modulus)
Compounds No. 5, 6: Membranes (Low modulus)

Components Compound No.

1 2 3 4 5 6
VISTALON 7000 100 -
VISTALON 3666 - 175
SRF N 762 55 - - - -
FEF N 550 55 50 - -
HAF N 347 - - - - 90
Chalk 85 - - - -
Paraffinic oil 75 30 - -
Zinc oxide 4 3 5
Polyethylene glycol 2 - - - -
Stearic acid - - 0.5 - -
Sulfur - - 0.3 0.3
Perkadox 14/40 8 7 5
KRASOL® PS-01 - 12 - 12 - 12
Uncured properties
Mooney ML(1+4), 100 °C 66 51.5 71 60 78 73.5
Scorch ML 140 °C (min.) 4.5 5.08 5.33 5.67 9.83 9.67
Vulcanization rate
3.08 5.00 4.83 6.67 8.83 10.80
ML 140 °C (min.)
Curemeter 180 °C
M H (N.m) 9.2 9.70 8.85 8.80 4.90 4.95
M L (N.m) 2.65 2.55 2.75 2.35 2.75 2.65
ts ((min.) 1.20 0.85 1 1 1.50 1.40
t90 (min.) 4.75 4.75 4.50 6 6 6.50

11
Table 6 ...Continued

Physical and mechanical properties

Tensile strength (MPa) 12.1 10.9 17.2 15.3 19.0 18.3
Elongation at break (%) 220.0 154.0 367.5 266.0 588.0 672.0
Modulus M100 (MPa) 3.9 5.5 2.5 2.7 0.9 0.8
IRHD 75.2 79.0 71.0 70.6 52.0 50.1
Aged properties 100 °C, 72 h.
Tensile strength (Mpa) 11.8 10.8 16.2 16.5 19.5 18.1
Elongation at break (%) 132.0 110.0 157.5 138.0 188.0 232.0
Modulus M100 (MPa) 4.4 6.1 3.5 3.2 0.7 0.5
IRHD 38.2 45.7 43.4 46.5 17.6 17.6
Weight change (%) 69.2 55.9 115.9 103.1 132.5 147.6
Volume change (%) 99.2 79.6 132.8 118.8 153.4 172.2
Tear strength
34.6 26.67 68.07 59.31 48.65 26.7
Angle 23 °C (N/mm)
Compression set 100 °C,
15.0 14.2 23.40 5.37 44.8 26.7
24 h. (%)
Resilience (%) 51.0 52.0 70.0 69.3 53.5 52.3
Test conditions: Mixing according to the ISO 4097 EPDM
Elastomers used:
VISTALON 7000 - EPDM, Mooney viscosity ML (1+4)@125 °C = 58, Diene: ENB, Ethylene
content: High, product of Exxon.
VISTALON 3666 - EPDM, Mooney viscosity ML (1+4)@125 °C = 52, Diene ENB, Ethylene
content: Medium, product of Exxon.

Conclusions (Table 6) Compounds No. 3, 4 and 5, 6:

Compounds No. 1, 2: In the basic parameters the influence of KRASOL®
The addition of KRASOL® polybutadiene results is similar like in the compounds No. 1, 2. In
in decrease of Mooney viscosity, improved scorch addition, a very important effect is reducing of the
characteristics, increase of MH and extended compression set. This is the reason why the
vulcanization optimum. compounds are designed for the manufacture of
sealing profiles and membranes.

12
Table 7 EPDM compound for the extrusion of hard sealing profiles

Components phr
Keltan 378 (EPDM, DSM) 100
Bralen VA 2012 (LDPE, Slovnaft) 41.67
Zinc white L-5 7.04
Stearic acid III flakes 1.48
Struktol 40 MS 3.70
KRASOL® LB 3000 22.22
Sulfenax CBS/MG 2.22
Perkacit TMTD/WOB.THIUR./ 0.56
Sulfur, ground, Class 1 3.52
Calsec CH 4.63
Carbon black CORAX N550 134.26
Oil, bearing 100 12.04
Uncured properties
Mooney viscosity, ML (1+4), 120 °C 50
t1 (min.) 2.5
t90 (min.) 5.0
t5 (min.) 12.0
Cured properties 160 °C, 15 min.
Tensile strength (Mpa) 10
Elongation at break (%) 200
Compression set (%) 50
Hardness Shore A (°Sh) 85-94
IRHD 86-95

Mixing conditions:
Bridge-Banbury mixer, chamber volume 147 litre, 110 - 130 °C
Mixing procedure: 0’ rubber
2’ additives, oil1/2 filler, plasticizers, vinyl silane
after heating: Bralen LDPE
8’ discharge of the compound

13
Examples of KRASOL® applications in rubber compounds

Tire compounds - Sidewalls, treads, retreading compounds (Tables 8, 9)

Table 8 KRASOL® polybutadiene in tire compounds

Compounds No. 1, 2: Sidewall compounds
Compounds No. 3, 4, 5: Tread compounds

Compound No.
Components 1 2 3 4 5
SMR 10 60 100
Buna cis 132 30 -
Stearic acid 2 2.5
Paraffin 2 1
Rosin 2 -
Oil, Aromatic (Triumf) 4 4
Zinc oxide 5 5
Carbon Black HAF 50 -
Carbon black ISAF - 48
Flectol H 1.5 1
Dusantox IPPD Antioxidant (phenylene diamine type) 1.5 1.5
Sulfenax CB 30 1.2 -
Sulfur 2 1.5
TBBS - 1.4
KRASOL® PS-01 - 10 - 6 12
Uncured properties
ML (1+4), 100 °C 52 47 44 48 43.5
Scorch Mooney 140 °C (min) 7.58 8.58 7.67 7.83 8.00
Vulcanization rate Mooney 140 °C (min.) 0.92 0.92 1.25 1.17 1.17
Curemeter 180 °C
MH (Mpa) 6.4 6.15 6.10 5.70 5.30
ML (Mpa) 2.4 2.5 2.15 2.15 2.00
ts (min.) 3.0 3.15 2.75 3.00 3.00
t90 (min.) 5.25 5.50 4.75 4.50 5.00
Cured properties
Tensile strength (Mpa) 20.8 19.3 27.0 26.8 25.6
Elongation at break (%) 516 504 550 570 578
Modulus M100 (Mpa) 2.5 2.5 2.6 2.2 1.9
Modulus M300 (Mpa) 10.6 10.2 12.6 11.0 10.0
IRHD 66.0 65.0 67.0 64.0 61.0
Aged properties
Tensile strength (Mpa) 14.4 14.3 21.7 22.0 21.9
Elongation at break (%) 278 274 354 390 428
Modulus M100 (Mpa) 4.1 4.1 4.2 3.5 3.1
Modulus M300 (Mpa) - - 18.1 16.4 14.6
IRHD 73.0 73.0 75.0 75.0 69.0
Tear strength Angle 23 °C (N/mm) 62.7 94.9 92.6 109.5 115.2
Compression set (%) 23 °C, 24 h. 7.7 8.6 8.9 9.5 9.2
Rebound resilience ISO 4662, 23 °C (%) 58.0 52.7 55.3 54.3 54.0
Abrasion resistance ISO/DIS 4649 (mm3) - - 121.7 127.3 134.5
Flex resistance ISO 132 (kcykl) - - 23 161 215
Flexometer Goodrich
Temperature rise (°C) - - 39.0 38.8 35.3
Permanent set (%) - - 4.15 4.21 4.38
Dynamic flow (%) - - 2.17 3.22 2.57
Mixing method: According to the ISO/DIS 1658-NR

14
Conclusions (Table 8) • improved scorch resistance (at 140°C and
The effect of KRASOL® polybutadiene in tire com- 180°C)
pounds tested can be summarized as follows: • enhanced tear strength

Sidewall compounds No. 1, 2: Tread compounds No. 3, 4, 5:

The addition of KRASOL® polybutadiene resulted The addition of KRASOL® polybutadiene resulted
in in
• increase of elongation
• decrease of Mooney viscosity M(1+4) • enhanced tear strength
• improved processability • significant increase in flex resistance (up to
eight times)

Table 9 KRASOL® polybutadiene in retreading compounds

Compound No.
Components 1 2 3 4
SBR 1712 (SKMS-30ARKM-27) 100 100 100 100
Carbon black P 234
75 75 75 75
(Russian Standard GOST 7885-86)
Aromatic oil “Plastar” 32 29 27 22
Krasol® LB 2000 - 3 5 10
Processability of the compounds
Processability (degree) Internal method
3-4 4 4 4-5
(Evaluation on calender rolls)
-1
Cohesive strength (kN.m ) 10.2 21.2 17.2 19.0
Physical and mechanical properties of vulcanizates
Tensile strength (MPa) 14.0 12.1 14.3 12.4
Elongation at break (%) 724 791 756 766
Modulus M 300 % (Mpa) 4.2 3.1 4.2 3.4
Tear strength (kN/m) 50 49 49 47
Hardness Shore A @ 20 °C (°Sh) 52 51 53 51
Resilience at 20 °C (%) 16 14 14 13
Resilience at 100 °C (%) 30 32 33 27

Conclusions A partial substitution of processing oil by the liquid

Substitution of even small part (3 phr) of aromatic polybutadiene KRASOL® results in reduced tack
oil in the compound by KRASOL® LB brought a of the compound (lower cohesive strength) that can
substantial change of physical properties in the significantly improve processability of the
compounds, in particular, the cohesive strength was compound.
about doubled.

15
Rubber foam compounds - Shoe soles

Table 10 KRASOL® polybutadiene in rubber foam compounds

Compound No.
Components 1 2 3 4
SMR L 100
Zinc oxide S6 3
Stearic acid III 2.5
Paraffin 2.5
Chalk (CaCO3) Triton 98.5
Titanium white 15
Altax (MBTS) 1.125
Kaptax (MBT) 0.625
Denax (DPG) 0.156
Sulfur, ground oiled 2.25
KRASOL® LB 3000 3 7 15 30
Uncured properties
Initial Mooney viscosity (ML) 39.95 37.14 30.49 29.10
ML (1+4)@ 100 °C 28.90 26.47 21.82 20.80
MH (Nm) 3.45 3.10 2.68 2.07
ML (Nm) 0.47 0.43 0.38 0.38
t1 (min.) 3.1 3.2 4.0 4.8
t90 (min.) 7.0 7.8 8.1 9.5
Cured properties 145 °C, 24 min.
Modulus M 100 (Mpa) 1.63 1.50 1.26 0.89
Modulus M 300 (Mpa) 3.08 2.89 2.45 1.81
Tensile strength (MPa) 15.8 16.0 15.7 14.3
Elongation at break (%) 600 610 650 700
Hardness Shore A (°Sh) 51 48 43 34
Elasticity according to Schob (%) 62 60 58 53
Tension set (%) 36 34 34 30
Compression set…(%) 3 days, 70 °C 41 39 39 37
Vulcanizate properties after aging 70 °C, 14 days
Modulus M 100 (Mpa) 1.86 1.67 1.47 1.10
Modulus M 300 (Mpa) 3.47 3.09 2.65 2.00
Tensile strength (MPa) 10.3 11.2 10.9 10.7
Elongation at break (%) 480 500 530 580
Hardness Shore A (°Sh) 54 52 48 38
Elasticity according to Schob (%) 59 58 56 52
Tension set (%) 24 24 26 30
Change in properties after aging
Modulus M 100 (%) 114.1 111.3 116.7 123.6
Modulus M 300 (%) 112.7 106.9 108.2 110.5
Tensile strength (%) 65.2 70.0 69.4 74.8
Elongation at break (%) 80.0 83.6 81.5 82.9
Hardness Shore A (%) 105.9 108.3 111.6 111.8

Mixing conditions:
Pomini-Farrel laboratory internal mixer Chamber 1570 cm3
Initial temperature 50 °C
Speed 80 min -1
Mixing time 5 minutes
Mixing procedure: 0 min. Rubber SMR L, stearic acid, paraffin, ZnO, TiO2
0.5 min. Chalk 1/2 (CaCO3)
2.5 min. Chalk 1/2, KRASOL LB
5 min. Discharge
Additional mixing of the compound after cooling on laboratory two roll mill 150 x 400 mm.

16
Conclusions Compounds for rubber - metal parts
Increasing amount of KRASOL® polybutadiene in
the compound results in: Highly filled chloroprene rubber compounds
for coating of metal surfaces
• substantially reduced viscosity of the The use of KRASOL® LB liquid polybutadienes
compound can resolve some serious problems in industrial
• lowered minimum and maximum moduli rubber applications such as strong tack of
• moderately increased scorch resistance and compounds on mill rolls and consequent trouble
vulcanization optimum in the processing.

The good tack of the compound to the rolls remains An example:

unaffected by KRASOL®. A highly filled compound designed for coating of
metal rolls by a hard rubber compound based on
KRASOL® does not affect aged properties of chloroprene rubber with a very low content of
vulcanizates. crystalline phase (such as Neoprene GW, Skyprene
R 10, Europrene SC 10) filled with:
The compounds with KRASOL® LB (15 and 30
phr) were successfully tested in the manufacture • diantimony trioxide 10 phr
of soles for home shoes. • kaolin 65 phr
• carbon black 22 phr
• aromatic oil 13 phr

showed a very strong tack at mixing on water-

cooled two roll mills (550x1500 mm).

KRASOL® LB 2000 added to the compound in the

amount of 3 phr completely eliminated the tack. In
addition to that, it significantly improved further
processing of the compound: the surface of the
extruded band was smoother and could be perfectly
wound on the roll body.

17
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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
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1571 06/06