Rubber
Handbook
Struktol Rubber Handbook
Table of Contents
About Struktol Company of America
6
Introduction
7
Function of Processing Additives
8
What are Processing Additives?
9
History of Processing Additives
10
Classification of Processing Additives
12
Lubricants
14
Fatty Acids
14
Fatty Acid Esters
15
Metal Soaps
15
Fatty Alcohols
16
Fatty Acid Amides
16
Organosilicones
16
Polyethylene and Polypropylene Waxes
16
Other Products
16
Properties and Mode of Action of Lubricants
17
Processing with Lubricants
24
Struktol Products and their Use
25
Applications with STRUKTOL® ZB 47
Physical and Chemical Peptizers
25a
26
What are the Benefits of Peptizing Agents?
31
Low Viscosity Natural Rubber
32
Processing with Peptizing Agents
33
Struktol Products and their Use
33
Table of Contents
1
Homogenizing Agents
Hydrocarbon Resins
37
Coumarone Resins
38
Petroleum Resins
38
Copolymers
38
Terpene Resins
39
Asphalt and Bitumen
39
Rosins
40
Phenolic Resins
41
Lignin
41
Processing with Homogenizing Agents
42
Struktol Products and their Use
42
Dispersing Agents
43
Processing with Dispersing Agents
43
Struktol Products and their Use
43
Tackifiers
44
Processing with Tackifiers
45
Struktol Products and their Use
45
Plasticizers
46
Processing with Plasticizers
49
Struktol Products and their Use
49
Preparations
50
Struktol Products and their Use
52
Metal Oxide Preparation
52
Sulphur Preparations
52
Activators
Processing with Cure Activators
2
35
54
59
Table of Contents
Silane Coupling Agents
60a
Properties
60a
An Overview
60c
Rubber Industry Applications
60f
Parting Agents
61
Parting Agents for Uncured Compounds and In-process Materials
61
Mold Release Agents
62
Dusting Agents
63
Organic Mold Release Agents
64
Silicone Oils
65
Semi-permanent Mold Release Agents
65
Compound Lubricants
66
Struktol Products and their Use
67
Mandrel Release Agents
67
Semi-permanent Mold Release Agents
68
Struktol Permalease Grades
68
Silicone Oils
69
Mold Cleaning Compounds
70
The Influence of Processing Additives on Discoloration
70
Peroxide Disperisons
70a
Peroxide Demand
71
Rubber to Metal Adhesion
72
Test Methods – Assessment of Processing Additives
72
Dispersion and Homogeneity
73
Rheological Tests
73
Mooney Shearing Disc Viscosimeter
74
Defo Tester
74
Table of Contents
3
High Pressure Capillary Rheometer
74
Torsion Strain Rotorless Shear Rheometer
74
Rubber Processability Analyzer
75
Oscillating Disc Cure Meter
75
Laboratory Extruder
75
Plasticorder
75
Laboratory Open Mill and Spiked Roller
75
Rheo-vulcameter
76
Transfer Sprial Test
76
Building Tack
77
Mold Release
77
Processing Additives in Pharmaceutical Articles
78
Ecology and Toxicology of Processing Additives
82
Application of Processing Agents - Examples
4
Lubricants
84
Peptizers
86
Homogenizing and Tackifiers
88
Plasticizers
90
Metal Oxide Preparations
92
Sulphur Preparations
94
Vulcanization Activators
96
Mold Release Agents
98
Mold Release Agents / Shaped Hose Release Agents
100
Mold Cleaning Compounds
102
Lubricants in Selected Elastomers
104
Higher Extrusion Rates with STRUKTOL® WB 16
112
STRUKTOL® WS 280 Paste in FKM
114
STRUKTOL® WB 42 – Bloom Study
116
Table of Contents
STRUKTOL® ZP 1014 – Curative for XNBR
119
STRUKTOL® ZEH vs. Stearic Acid in NR
120
Homogenization Study
123
Mold Cleaning with STRUKTOL® MC-A
124
Additional Useful Information
Crazing
125
Frosting
126
Revision – Sept. 2004
STP0206
/rca
Table of Contents
5
About Struktol Company of America
Struktol Company of America is a member of the Schill & Seilacher family of companies, with
representation in over 100 countries around the world. A global organization with over a century
of specialty chemical expertise, Schill & Seilacher markets most of their polymer processing
products under the brand name STRUKTOL® - a name that has become synonymous with both
quality and performance. Struktol chemicals are found in rubber and plastics as well as manmade fibers, textiles and leather and paper products. Since the late 1970’s, Struktol has become
North America’s dominant force in performance additives for the polymer industry. Struktol has
committed its research and development, ISO Certification and premier customer service to
establishing a leadership role with engineered additives for the rubber and plastics compounder.
The Struktol approach to the polymer additive business is by no means typical or ordinary.
Chemistry is as the heart of everything we do. Providing Intelligent Additive Solutions for
polymers and compounds, Struktol products are designed to meet the challenges and exacting
demands of our customers. Our technical specialists, R&D chemists and compound laboratory
are dedicated to creating innovative solutions for the ever-changing polymer industry; solutions
that keep you ahead of your competition with increased productivity, better quality parts and
lower overall cost.
In addition to premium product performance, Struktol customer service initiatives have become
the industry benchmark.
www.struktol.com
6
About Struktol Company of America
Struktol Products and their Use
STRUKTOL® WB 222 is an ester of saturated fatty acids. It is a highly effective lubricant
and release agent predominantly used for polar elastomers.
STRUKTOL® WB 212 is based on high molecular, hydrophilic fatty acid ester. The
product serves as a dispersing agent for powdered materials and has excellent release
properties.
STRUKTOL® WB16 is an excellent lubricant mainly for non-polar rubbers. As a mixture
of calcium soaps and amides of saturated fatty acids it can exhibit an activating effect.
STRUKTOL® HPS 11 is composed of fatty acid derivatives, which have been designed and
selected to give maximum polymer to additive interactions. HPS 11 is effective in increasing
flow, promoting release, and improves overall processing.
STRUKTOL® WB 42, a blend of fatty acid derivatives, provides improved flow in a wide
range of elastomers.
STRUKTOL® W A 48 is successfully used in epichlorohydrin rubber as an effective release
agent and lubricant.
STRUKTOL® W 34 is a dispersing agent and lubricant for nearly all elastomers. Faster
filler incorporation and avoidance of filler agglomeration in highly filled compounds can be
achieved.
STRUKTOL® WS 180 and STRUKTOL® WS 280 are organosilicone compounds which
combine outstanding release performance with good flow properties.
STRUKTOL® WS 180 can drastically reduce mold contamination.
STRUKTOL® ZB 47 is a formulated zinc soap that can be used for masticating NR
compounds. Also offers heat stability (Reversion Resistance). Very effective in mineral
filled NR compounds.
STRUKTOL® A 50, and A 60 are zinc soaps of unsaturated fatty acids. They are mainly
used as physical peptizers in NR compounds
STRUKTOL® EF 44 A is a blend of fatty acid derivatives with zinc soaps predominating.
The product is especially suitable for extrusions. It acts as a cure activator.
STRUKTOL® HM 97 is a mixture of low viscosity polyethylene waxes. Due to their
special lubricating effect, HM 97 is highly recommended in EPMD compounds.
*For further information on ZB 47 contact Struktol for our new ZB 47 Brochure and CD.
Lubricants
25
Struktol Company of America
201 E. Steels Corners Road • P. O. Box 1649 • Stow, Ohio 44224-0649
Producers of Specialty Chemicals
Struktol Rubber Lab
Project 04003
February 3, 2004
(addition April 20, 2004)
Project: Evaluate STRUKTOL® ZB 47 in a black / silica natural rubber tread compound
with and without silane coupling agent.
Conclusion: The combination of 1 phr disulfide silane (added as STRUKTOL®SCA 985
PL) with ZB 47 (added at 2.5 and 5 phr) showed both processing and physical property
synergism. When the silane was added it was at a level of 5% of the silica.
The mixing curves show that most of the processing improvements came from the
addition of ZB 47. There is a faster incorporation and lower mixing torque. The
resulting Mooney viscosity of the compounds was significantly improved with a drop of
about 40 points with the initial viscosity, and 10-15 points with the ML (1+4). In
addition, the scorch delay shows significant improvements with the combined products.
The rheometer cure reflects the viscosity improvements as well as the cure delay. The
final T90 was increased about 1 to 2 minutes with the combination. There were only
minor shifts in max torque. The reversion resistance was the greatest for the
combination. Cured physicals showed an increase in modulus with the silane and even a
greater increase with the combination. The ZB 47 by itself gave a slight increase in state
of cure. On air aging the retention of physicals was good. The combination gave the
lowest % change. Tear resistance (Die C) was improved with all stocks over the noncoupled control.
The dynamic properties as measured by rebound, Firestone Flexometer, and tan delta
were all improved by the combination of additives. The biggest change is seen in the
long-term dynamic distortion on the Flexometer where the combination was shut off
before the sample failed.
The compounded stock was aged 11 weeks and then tested for processing as stored.
There was an increase in initial viscosity of 40 to 50 Mooney units for the ZB 47
containing stocks. The initial reading for the blank and the silane stock was off scale.
The ML (1+4) for these two stocks was higher than the initial readings for the ZB 47
stocks. The ZB 47 stocks showed only a 5-6 point increase for ML (1+4).
The extruder results also showed that the ZB 47/silane decreased the pressure and torque,
and increased the rate. The quality of the extrudate was the best with the combination of
ZB 47 and silane.
25a
Lubricants
Formulae
1
2
3
4
5
6
SMR 5
100
100
100
100
100
100
STRUKTOL A 86
.25
.25
.25
.25
.25
.25
N220
40
40
40
40
40
40
SILLCA VN3
20
20
20
20
20
20
STEARIC ACID
2.5
2.5
2.5
2.5
2.5
2.5
ZNO
4
4
4
4
4
4
6PPD
2.5
2.5
2.5
2.5
2.5
2.5
FLECTOL H
1
1
1
1
1
1
STRUKTOL 40 MS
6
6
6
6
6
6
STRUKTOL SCA 985PL
0
2
0
0
2
2
STRUKTOL ZB 47
0
0
2.5
5
2.5
5
TBBS
1.5
1.5
1.5
1.5
1.5
1.5
SULFUR
1.5
1.5
1.5
1.5
1.5
1.5
179.25
181.25
181.75
184.25
183.75
186.25
2ND PASS
TOTAL:
First Pass
Compound
Temperature (°C)
Energy (WH)
1 - Control 1
140
217
2 – SCA 985PL
137
197
3 – ZB47, 2.5
140
202
4 – ZB47, 5
136
183
5 – SCA985PL, ZB47, 2.5
139
190
6 – SCA985PL, ZB 47, 5
135
176
Note: 70% fill factor
Lubricants
25b
Rheometer Data
Compound
1 - Control 1
160°C; 3° arc; 100 Range; 30 minutes
Min
Max
Ts2
T50
Torque Torque
19.59
76.01
3.75
7.29
8.63
T-2
Reversion
13.29
T90
2 – SCA 985PL
18.92
80.45
4.00
7.08
8.33
13.71
3 – ZB47, 2.5
16.23
75.74
3.75
8.13
9.63
15.29
4 – ZB47, 5
15.75
72.98
3.83
8.58
10.29
18.00
5 – SCA985PL, ZB47, 2.5
16.29
78.16
4.08
8.00
9.50
18.00
6 – SCA985PL, ZB 47, 5
15.15
75.74
4.33
8.42
10.25
25.92
Mooney Viscosity
ML (1+4) @ 100°C
Initial
Viscosity
Initial Viscosity
aged 11 weeks
ML (1+4)
1 - Control 1
147.5
-
86.6
ML (1+4)
Aged 11
weeks
213.5
2 – SCA 985PL
150.7
-
85.8
218.4
3 – ZB47, 2.5
123.8
196.6
76.0
83.7
4 – ZB47, 5
113.2
154.5
74.0
79.4
5 – SCA985PL, ZB47, 2.5
125.5
177.4
74.5
80.7
6 – SCA985PL, ZB47, 5
113.6
161.4
70.7
75.4
Compound
Extruder Data
Brabender Plasti-Corder
Compound
Torque
Garvey Die, 3:1 Meeting Screw
Cold feed 19 mm roller feeder
Weight (g)
RPM Temp
PSI
10 inch
26
108
864
25.98
One minute
Extrudate
24.58
Surface
Rating
B
Edge
1 - Control 1
66.6
2 – SCA 985PL
54.3
26
108
726
25.44
26.29
B
#7
3 – ZB47, 2.5
56.0
26
117
736
26.93
26.76
A
#8
4 – ZB47, 5
54.2
26
115
733
27.06
27.41
A
#8
5 – SCA985PL, ZB47, 2.5
56.8
26
112
747
26.82
25.93
A
#9
6 – SCA985PL, ZB47, 5
51.0
27
107
690
25.64
26.47
A
#9
25c
Lubricants
#6
Mooney Scorch
ML @ 125°C
Compound
Min Torque
T5
T35
Cure Index
1 - Control 1
72.1
24.41
40.95
16.54
2 – SCA 985PL
72.5
29.95
38.24
8.29
3 – ZB47, 2.5
65.8
28.75
45.84
17.09
4 – ZB47, 5
63.9
33.41
49.19
15.78
5 – SCA985PL, ZB47, 2.5
64.3
33.72
46.23
12.51
6 – SCA985PL, ZB 47, 5
60.6
37.66
47.82
10.16
Tensile Data
Unaged
Cure Time
160°C
Shore A
Duro
Tensile
(MPa)
Elongation
(%)
100%
Mod.
(MPa)
200%
Mod.
(MPa)
300%
Mod.
(MPA)
1 - Control 1
9
62
24.0
635
1.6
4.0
8.1
2 – SCA 985PL
8
67
25.2
620
2.0
5.0
9.8
3 – ZB47, 2.5
10
65
22.9
597
1.8
4.2
8.3
4 – ZB47, 5
10
65
23.6
643
1.7
4.0
7.6
5 – SCA985PL, ZB47, 2.5
10
69
24.8
612
2.1
5.3
9.8
6 – SCA985PL, ZB 47, 5
10
67
26.6
605
2.3
5.6
10.2
Compound
Oven Aged 70 Hrs @ 100°C
Cmpd
1
Shore
Points
A
Change
Duro
71
+9
Tensile
(MPa)
Pct.
Change
Elong
(%)
Pct.
Change
21.7
-9.6
498
-21.6
100%
Mod.
(MPa)
3.3
Pct.
Change
106
200%
Pct.
Mod.
Change
(MPa)
8.1
103
300%
Mod.
(MPa)
13.7
Pct.
Change
69
2
76
+9
22.3
-11.5
477
-23.1
3.8
90
9.4
88
15.2
55
3
75
+10
23.8
3.9
495
-17.1
3.9
117
9.2
119
15.1
82
4
77
+12
19.8
-16.1
454
-29.4
3.4
100
8.0
100
13.1
72
5
75
+6
23.5
-5.2
510
-16.6
4.0
90
9.6
81
15.1
54
6
76
+9
22.5
-15.4
471
-22.1
4.1
78
9.5
70
15.0
47
Lubricants
25d
Firestone Flexometer
Heat Build-up
250 lb. Weight; 0.325” Throw; 45 min. test
Compound
Cure Time @ 160°C
Duro
Temp. °C
1 - Control 1
36
57
164
2 – SCA 985PL
32
64
129
3 – ZB47, 2.5
40
58
141
4 – ZB47, 5
40
61
139
5 – SCA985PL, ZB47, 2.5
40
63
133
6 – SCA985PL, ZB 47, 5
40
64
127
Blow Out
250 lb. Weight; 0.325” Throw; test until sample fails
Compound
1 - Control 1
Time
1 Hr 5 Min
2 – SCA 985PL
11 Hrs 20 Min
3 – ZB47, 2.5
3 Hrs 50 Min
4 – ZB47, 5
14 Hrs 42 Min
5 – SCA985PL, ZB47, 2.5
>103 Hrs
6 – SCA985PL, ZB 47, 5
> 143 Hrs 51 Min
Tear Strength
ASTM D-624 Die C
Compound
25e
Tear Strength (N/mm)
1 - Control 1
92.6
2 – SCA 985PL
132.5
3 – ZB47, 2.5
95.2
4 – ZB47, 5
102.2
5 – SCA985PL, ZB47, 2.5
113.3
6 – SCA985PL, ZB 47, 5
108.3
Lubricants
Rebound
Compound
0°C
Room Temp
100°C
1 - Control 1
18
35
50
2 – SCA 985PL
16
34
53
3 – ZB47, 2.5
16
33
51
4 – ZB47, 5
15
33
52
5 – SCA985PL, ZB47, 2.5
17
34
54
6 – SCA985PL, ZB 47, 5
15
32
55
MER / COMPRESSION / CYLINDRICAL / 1 HZ / 23°C
Compound
Complex Power
Loss Power
Tan Delta
Stiffness
1 - Control 1
.3198
.05150
.163
37.21
2 – SCA 985PL
.2016
.02703
.135
15.54
3 – ZB47, 2.5
.2556
.04223
.167
12.23
4 – ZB47, 5
.2145
.03164
.149
14.63
5 – SCA985PL, ZB47, 2.5
.2052
.02953
.145
15.35
6 – SCA985PL, ZB 47, 5
.1841
.02400
.131
16.94
MER / COMPRESSION / CYLINDRICAL / 1 HZ 100°C
Compound
Complex Power
Loss Power
Tan Delta
Stiffness
1 - Control 1
.1534
.0656
.131
6.118
2 – SCA 985PL
.4330
.0482
.112
7.219
3 – ZB47, 2.5
.5836
.0796
.152
5.403
4 – ZB47, 5
.5043
.0597
.119
6.18
5 – SCA985PL, ZB47, 2.5
.4400
.04452
.102
7.154
6 – SCA985PL, ZB 47, 5
.4257
.04041
.095
7.341
Lubricants
25f
Mix Data-Control/Si
10
350
Energy (KW)
9
Motor (KW) Si
Temperature (F°) Control
300
8
7
Temperature (F°) Si
250
6
200
5
150
4
3
100
Temperature (F°)
Motor (KW) Control
2
50
1
0
0
0
50
100
150
200
250
Time (Sec.)
Figure 1
Mix Data-Control/2.5ZB
10
350
Motor (KW)
9
Motor (KW) 2.5ZB
8
250
Temperature (F°) 2.5ZB
6
200
5
150
4
3
100
2
50
1
0
0
0
50
100
150
200
250
Time (Sec.)
Figure 2
25g
Lubricants
Temperature (F°)
Temperature (F°)
7
Energy (KW)
300
Mix Data-Control/5.0ZB
10
350
Motor (KW) Control
9
250
Temperature (F°) 5.0ZB
6
200
5
150
4
3
100
Temperature (F°)
Temperature (F°) Control
7
Energy (KW)
300
Motor (KW) 5.0ZB
8
2
50
1
0
0
50
100
150
200
0
250
Time (Sec.)
Figure 3
Mix Data-Control/2.5ZB, Si
10
350
Energy (KW)
9
Motor (KW) 2.5ZB, Si
Temperature (F°) Control
300
8
7
Temperature (F°) 2.5ZB, Si
250
6
200
5
150
4
3
100
2
50
1
0
0
0
50
100
150
200
250
Time (Sec.)
Figure 4
Lubricants
25h
Temperature (F°)
Motor (KW) Control
Mix Data-Control/5.0ZB, Si
10
350
Motor (KW) Control
9
300
Motor (KW) 5.0ZB, Si
Temperature (F°) Control
7
250
Temperature (F°) 5.0ZB, Si
6
200
5
150
4
3
100
2
50
1
0
0
0
50
100
150
200
250
Time (Sec.)
Figure 5
25i
Lubricants
Temperature (F°)
Energy (KW)
8
STRUKTOL® ZB 47
Developed for high natural rubber compounds, both black and mineral-filled, ZB 47
allows for:
•
Lower compound viscosity
•
Lower heat build-up
•
Higher compound modulus
•
Improved permanent set
•
Improved physical properties
•
Improved dynamic properties
•
Improved blowout resistance
•
Improved heat aged properties
•
Improved cut growth resistance
With STRUKTOL® ZB 47 you will have lower mixing temperatures, faster filler
incorporation, and faster mixing cycles!
Contact Struktol Company of America now for our new brochure on ZB 47.
Phone: 800-327-8649 or 330-928-5188
E-mail: customerservice@struktol.com
Lubricants
25j
Processing with Homogenizing Agents
The homogenizing agents are usually added at the beginning of the mixing cycle,
particularly when elastomer blends are used. They exhibit optimum effectiveness at
around their softening temperature.
The recommended dosage is between 4 and 5 phr. Difficult to blend elastomers will
require an addition of 7 to 10 phr.
Struktol Products and their Use
STRUKTOL® 40 MS FLAKES is a mixture of dark, aromatic hydrocarbon resin which
has a very good compatibility with most standard elastomers, such as SBR, NR, NBR,
CR, IIR, BIIR, EPDM and BR and is used in elastomer blends and homopolymer
compounds. Blending of elastomers with different polarities and/or viscosities are
significantly facilitated. In particular difficult to process tire tube and innerliner
compounds have been significantly improved with STRUKTOL 40 MS FLAKES.
STRUKTOL 60 NS FLAKES is a mixture of light-colored aliphatic hydrocarbon resin.
It is designed for light-colored compounds where non-staining is specified. Its action is
comparable with that of STRUKTOL 40 MS FLAKES. This product has proven its
value, particularly in compounds based on NBR/EPDM blends.
STRUKTOL TH 10 A is a mixture of aliphatic and aromatic resins. It is a processing
additive that gives good tack and homogeneity in row compounds. Due to the balanced
combination of the tackifying resins and homogenizing agent, an optimum dispersion of
the ingredients in the raw compound is achieved which maintains its greet tack for
several weeks under normal storage conditions.
STRUKTOL® TH 64 is a mixture of low molecular weight resins. It can be used as a
tackifier for natural and synthetic elastomers for improving long-term building tack.
STRUKTOL® STRUKREZ 110 is a polymeric resin blend. Blending of elastomers
with different polarities or viscosities are significantly facilitated.
STRUKTOL® STRUKREZ 220 is a molecular assembled resin designed for unique
qualities in polymer processing. Green tack is improved with STRUKREZ 220.
42
Homogenizing Agents
Silane Coupling Agents
Struktol Silane Coupling Agents are used in rubber compounding. They provide coupling of non-black pigments
to the polymer backbone allowing for: Improved abrasion resistance, Higher compound modulus, Lower hystersis,
Improved compression set, Improved rolling resistance in tire tread compounds.
Product name:
Chemical composition:
Features:
STRUKTOL® SCA 98
Bis (3-triethoxysilylpropyl)
tetrasulfide
• Improves reinforcing
capabilities of fillers with
silanol groups
Product
form:
Typical data:
Sulfur content:
21-23%
Yellow liquid
Specific gravity: 1.089
• Improves abrasion
resistance
• Provides higher compound
modulus
• Improves rolling resistance
in tread compounds
STRUKTOL® SCA 98CB
Same as SCA 98
• Same as SCA 98
Sulfur content:
10-12%
Black powder
Specific gravity: 1.34
STRUKTOL® SCA 98PL
Same as SCA 98
• Same as SCA 98
Sulfur content:
10-12%
Pale yellow
pastille
Specific gravity: 1.00
STRUKTOL® SCA 98WT
Same as SCA 98
• Same as SCA 98
Sulfur content:
7.5-16%
Off white
powder
Specific gravity: 1.43
STRUKTOL® SCA 984
STRUKTOL® SCA 985
3-Thiocyanatopropyltriethoxy
silane
Bis (3-triethoxysilylpropyl)
disulfide
• Improves compound
modulus
• Improves compression set
Sulfur content:
12%
• Improves abrasion
resistance
Specific gravity: 1.03
• Improves reinforcing
capabilities of fillers with
silanol groups
Sulfur content:
12-14%
Amber
colored
liquid
Yellow liquid
Specific gravity: 1.04
• Improves abrasion
resistance
• Provides higher compound
modulus
• Improves rolling resistance
in tread compounds
Silane Coupling Agents
60a
Silane Coupling Agents
Product name:
Chemical composition:
Features:
STRUKTOL® SCA 985PL
Bis (3-triethoxysilylpropyl)
disulfide
• Same as SCA 985
Product
form:
Typical data:
Sulfur content:
6-7%
Pale orange
pastille
Specific gravity: 1.00
STRUKTOL® SCA 989
3-Mercaptopropyltriethoxy
• Improves tensile strength
silane
• Improves tear strength
STRUKTOL® SCA 989 WT 3-Mercaptopropyltriethoxy
silane
MPTES content
≥95%
• Improves abrasion
resistance
Specific gravity: 0.98
• Same as SCA 989
SCA 989 content: 70%
Clear liquid
Light gray
powder
Specific gravity: 1.20
STRUKTOL® SCA 960
γ-Glycidyloxypropyl
trimethoxy silane
• Mainly used in glass
reinforced epoxy resin,
ABS, nylon and PBT
SCA 960 content: >95.0%
• Improves tensile strength
• Improves tear strength
Density:
Clear liquid
1.070+0.050
• Improves relative
extensibility
STRUKTOL® SCA 972
Vinyl tri(2-methoxyethoxy)
silane
• Improves the reinforcing
capability of fillers with
silanol groups in peroxide
cured compounds
SCA 972 content: >98.0%
Density:
Clear liquid
1.040+0.020
• Improves tensile strength
• Improves tear strength
• Improves abrasion
resistance
STRUKTOL® SCA 974
γ-Methacryloxypropyl
trimethoxy silane
STRUKTOL® SCA 974WT Same as SCA 974
• Improves coupling of fillers SCA 974 content: >97.0%
Clear liquid
with silanol groups, and
fiberglass in the resin/
1.040+0.020
Density:
polymer matrix
• Same as SCA 974
SCA 974 content: 70.0+2.0
Density:
STRUKTOL® SCA 1100
Aminopropyl triethoxy silane
Clear liquid
1.598+0.020
• Improves the reinforcing
Colorless
Min. purity:
98.0%
properties of fillers
liquid
containing hydroxyl groups Specific gravity: 0.941+0.01
(07/07/04)AAC/rca
60b
Silane Coupling Agents
STRUKTOL® SCA 98 & SCA 985
An Overview
STRUKTOL® SCA 98 and SCA 985 are silane coupling agents for use in rubber compounding.
When used in rubber compounding, they provide coupling of non-black pigments to the polymer
backbone allowing for:
Improved abrasion resistance
Higher compound modulus
Lower hysteresis
Improved compression set
Improved rolling resistance in tire tread compounds
The theory for their effectiveness is that the silane portion of the molecule couples with OH
groups on the silica and silicate surfaces in non-black pigments. The sulfur portion of the molecule is available for curing activity and can enter into the vulcanization mechanism. The SCA 98
is a tetra-sulfide silane while the SCA 985 is a di-sulfide silane. When the SCA 985 is used as a
1:1 replacement for the SCA 98, a reduction in the cured modulus and maximum tensile may be
noticed. This can usually be regained by increasing the sulfur level in the final mix pass.
THE REINFORCEMENT OF NON-BLACK FILLERS IS
ENHANCED BY STRUKTOL®SCA 98 & SCA 985
Silica, ppt
Clay
Suggested Dosage phr
Levels per 100 phr filler
3 – 13
0.3 – 1.0
Calcium Stearate
6–7
Magnesium Silicate (talc)
1–4
Fumed Silica
3 - 15
Silane Coupling Agents
60c
MIXING AND DUMP TEMPERATURE
Part or all of the non-black filler should be dispersed with the STRUKTOL® SCA 98/SCA 985
in the first mixing stage. The remaining ingredients should be added after the silane coupling
agent and the filler have been incorporated. Curatives should be added in the last mixing stage.
SUGGESTED TYPICAL MIX SCHEDULE
0'
Rubber
½'
½ to all non-black pigment STRUKTOL® SCA 98/SCA 985
2½'
Black, if present, oil, stearic acid, zinc oxide
3½'
AO2 , AO3
4½'
Clean
5'
Dump
Because of the sulfur present in the STRUKTOL® SCA 98/SCA 985, it is necessary to control
the maximum mixing temperature.
The following are recommended dump temperatures:
60d
Natural Rubber
150°C
SBR
150-160°C
NBR
140°C
Silane Coupling Agents
POLYMERS AND STRUKTOL® SCA 98/SCA 985 EFFECTIVENESS
ACM
IIR
CM
XNBR
EPDM
ECO
FKM
HIIR HALOBUTYL
CSM
NATURAL RUBBER
CR
NBR
BR
IR
SBR
URETHANTE
VAMAC
NDA
GOOD
GOOD
GOOD
EXCELLENT
EXCELLENT
NDA
GOOD
EXCELLENT
EXCELLENT
EXCELLENT
EXCELLENT
EXCELLENT
EXCELLENT
EXCELLENT
GOOD
GOOD
Excellent - STRUKTOL® SCA 98/SCA 985 favorably influences properties, producing
significant improvements in physical properties and state of cure.
Good - STRUKTOL® SCA 98/SCA 985 has an effect on physical properties producing enhanced
modulus and improved abrasion.
NDA - No data available in actual experience with STRUKTOL® SCA 98/SCA 985.
Silane Coupling Agents
60e
AREAS OF RUBBER INDUSTRY WHERE
STRUKTOL® SCA 98/SCA 985 WOULD BE BENEFICIAL
Footwear
- abrasion resistance
- cutting and chunking resistance
- flex life improvement
Rolls
- abrasion resistance
- aging resistance
- processing
- set reduction (better load bearing)
- reduced water swell
- lower hysteresis
Mechanical Molded
Goods
- increased modulus
- better heat aging
- compression set reduction
- dynamic property improvement
- reduced swell to polar liquids
- filler substitution (non-black for black)
Hose
- improved abrasion on cover
- better heat aging
- increased modulus
- lower compression set
- improved adhesion to reinforcing elements
Solid Tires
- improved abrasion
- lower hysteresis
- higher modulus
- improved processing
60f
Silane Coupling Agents
Tires
- treads for abrasion, hot tear, improved rolling resistance,
- lower hystersis
- carcass for adhesion and/or filler substitution
- breaker (belt) stocks for adhesion
Belts - Flat Belts
- increased abrasion
- improved reversion resistance
- reduced cost with clay substitution for black
- improved cord adhesion
- increased flex life and modulus
Belts - V Belts
- increased modulus
- improved abrasion
- longer flex life
- improved adhesion to reinforcing elements
Silane Coupling Agents
60g
Struktol Silane Coupling Agents
Struktol silane coupling agents are for use in rubber compounds, particularly mineral-filled, and
allow for:
•
Lower compound viscosity
•
Higher compound modulus
•
Improved abrasion resistance
•
Lower hysteresis
•
Improved compression set
•
Improved rolling resistance in tire tread compounds
•
Improved dispersibility
•
Faster incorporation
Contact Struktol Company of America now for our Silane Coupling Agents brochure with CD.
Phone: 800-327-8649 or 330-928-5188
E-mail: customerservice@struktol.com
60h
Silane Coupling Agents
Peroxide Dispersions
Struktol peroxide dispersions are widely used in crosslinking several polymers in the
rubber industry, as well as acting as a viscosity reducer in polypropylene. The
proprietary carriers aid in dispersing the peroxide and will reduce incorporation time.
Product name:
STRUKTOL®
Peroxide DCP 70
STRUKTOL®
Peroxide DBDB 60
Chemical composition:
70% active Dicumyl
60% active α,α’-bis
(tert-butylperoxy)diisopropylbenzene
Peroxide Dispersions
Features:
Product
form:
Typical data:
• Higher peroxide content
• FDA sanctioned
• Improved dispersion
• Easy handling
Melting point:
30-40 °C
Specific gravity:
1.071
• Higher peroxide content
• Improved dispersion
• Easy handling
Dropping point:
73-82 °C
Specific gravity:
0.955
70a
white
pastille
off-white
pastille
MOLD CLEANING WITH STRUKTOL® MC-A
Moving Die Rheometer Cavity
Press Mold
124
Examples for the Application of Processing Agents