1
HOW TO CHOOSE THE BEST VULCANIZATION SYSTEM WHEN USING A NITRIFLEX N-615B
COMPOSITION.
Nitrile Rubbers(NBR) are commonly used in industry, due to
its good resistance to oils and solvents.
Normally, it is necessary to stress some important property,
according to the end use of the artifact. Those properties
are influenced by type and amount of: carbon black filler,
mineral fillers, and plasticizers.
However, there is another influence less studied, the
vulcanization system. Below follows a study of different
vulcanization systems used in fractions of the same rubber
compound, where the influences of each special vulcanization
system are analyzed.
COMPONENT
PHR
N-615B
ZnO
Estearina
Polylite E
FEF 550
SRF
CaCO3
Viernol XH-8
DOP
Santoflex 13
100,0
5,0
0,5
1,0
10,0
80,0
20,0
12,0
5,0
2,0
Vanox ZMTI
1,0
AA
E
AMAX#1
CBS
CZ
DPG
MBT
MBTS
Peróxido
DC 40%
S
Santocure
Santocure
MOR
Santocure
NS
Santogard
PVI
Sulfazan R
TMTD
TMTM
ZDEC
TABLE 01 BASIC FORMULATION
DESCRIPTION
PRODUCER
NBR
Zinc oxide
Stearic acid
Nonylated diphenylamine
Carbon black
Carbon black
Calcium carbonate
Liquid Polyester blend
Dioctylphtalate
N-(1,3-dimethylbutyl)-N’-fenyl-pfenylenediamine
Zinc 2-mercaptotolylimidazol
NITRIFLEX
Rubberox
Cia. Paranaense
Uniroyal
Cabot do Brasil
Cabot do Brasil
Barra do Piraí
Scandiflex
Ipiranga Química
Flexys
R.T. Vanderbilt
TABLE 2 VULCANIZATION SYSTEMS
AB AC AD AE AF AG AH AI AJ AK AL
E
E
S
E
S
E
S
P
E
E
S
AM AN AO AP
AQ
E
S
C
C
E
0,4
1,0
1,2
2,0
1,5
0,4
1,0
2,5
1,5
2,0
1,5
0,5
0,5
2,0
1,0
1,5
3,0
0,5
0,4
2,0
0,4
1,5
1,5
0,2
0,4
0,5
1,5
1,5
2,0
0,8
1,0
1,0
0,7
0,1
2,0
2,0
2,0
1,0
1,5
1,0
2,5
0,2
2,0
1,2
1,2
2,0
0,5
2,0
2,0
E-EFFICIENT ; S-SEMI EFFICIENT ; P-PEROXYDIC; C-CONVENTIONAL
NITRIFLEX S.A. INDÚSTRIA E COMÉRCIO – Based on a paper presented at :
EXPOBOR 96- October, 15 to 18 1996 - São Paulo - SP- BRASIL
0,2
2,0
2
TABLE
Commercial name
AMAX#1
CBS
CZ
DPG
MBT
MBTS
Peróxido DC 40%
S
Santocure
Santocure MOR
Santocure NS
Santogard PVI
Sulfazan R
TMTD
TMTM
ZDEC
3 – COMPONENTS DESCRIPTION
Description
90% of 2-morfolinatiobenzotiazol-2-sulfenamide + 10% of 2,2’mercaptobenzotiazoldisulfide
N-ciclohexylbenzotiazol-2-sulfenamide
N-ciclohexylbenzotiazol-2-sulfenamide
difenyl-guanidine
2-mercaptobenzotiazol
2,2’mercaptobenzotiazol disulfide
Cumyl peroxide @ 40%
Sulfur
N-ciclohexylbenzotiazol-2-sulfenamide
2-morfolinatiobenzotiazol-2-sulfenamide
N-t-butylbenzotiazol-2-sulfenamide
Ciclohexyltioftalimide
4,4’-ditiomorfoline
Tetramethyltiuram disulfide
tetramethyltiuram monosulfide
Zinc diethylditiocarbamate
The compounds were accelerated and vulcanized until T90,
according to figure 1 and let rest for 48 hours before
physical tests.
FIGURE 1
min.
20
18
16
14
12
10
8
6
4
2
0
T90%
Ts1
AA AB AC AD AE AF AG AH
AI
AJ AK AL AM AN AO AP AQ
RHEOMETRY – VULCANIZATION TIMES
NITRIFLEX S.A. INDÚSTRIA E COMÉRCIO – Based on a paper presented at :
EXPOBOR 96- October, 15 to 18 1996 - São Paulo - SP- BRASIL
3
ORIGINAL
AIR
FIGURE 2
2
N/mm
OIL
21
19
17
15
13
11
9
7
AA
AB
AC
AD
AE
AF
AG AH
AI
AJ
AK
AL
AM AN
AO AP
AQ
Variation of TENSILE STRENGTH prior and after aging
ORIGINAL
AIR
FIGURE 3
2
N/mm
OIL
480
430
380
330
280
230
180
130
80
AA AB
AC AD
AE
AF
AG AH
AI
AJ
AK
AL
AM AN AO AP AQ
Variation of ELONGATION AT BREAK prior and after aging
ORIGINAL
AIR
FIGURE 4
2
N/mm
OIL
90
85
80
75
70
65
60
AA
AB
AC
AD
AE
AF
AG AH
AI
AJ
AK
AL
AM AN
AO AP
Variation of HARDNESS prior and after aging
NITRIFLEX S.A. INDÚSTRIA E COMÉRCIO – Based on a paper presented at :
EXPOBOR 96- October, 15 to 18 1996 - São Paulo - SP- BRASIL
AQ
4
FIGURE 5
%
90
74,1
80
71,4
70
55,9
60
60,4
58,6
45,9 45,9 43,5
45,1 42,6
50
35,5
40
39,7
35
27
30
20 15,5
20,3
13,4
10
0
AA AB AC AD AE
AF AG AH
AI
AJ AK
AL AM AN AO AP AQ
COMPRESSION SET
FIGURE 6
%
AA AB AC AD
AE AF AG AH
AI
AJ AK
AL AM AN AO AP AQ
8
6,5
7
6
5
4
3
1,7
2
1
0
-1
-2
-2,1 -2,1 -2,3
-3 -2,4 -2,5
-2,5
-2,6
-2,7
-2,8 -2,6 -3,0 -2,8 -2,6 -2,6 -2,5
-4
OIL SWELL - ASTM 3 OIL
COMMENTS.
Vulcanization times - the fastest system was AL.
Tensile strength - several systems presented maximum
value in the original compound. However, formulation AH
was able to keep its good original properties after
aging.
Elongation at break - in the original formulation, the
best result was for the peroxide system(AI). Formulation
AC presented the narrowest variation of properties after
aging.
Hardness - formulation
variation after aging.
AD
presented
the
narrowest
Compression set - AP was the lowest(best) result.
Oil swell – AF presented the best result.
As it can be seen on the above comments, there is not
such thing as “the best vulcanization system”. However, on
trying to extract from all this database, which system
performs better in general, a system of points were created.
Every analyzed property was ordered and points were added to
NITRIFLEX S.A. INDÚSTRIA E COMÉRCIO – Based on a paper presented at :
EXPOBOR 96- October, 15 to 18 1996 - São Paulo - SP- BRASIL
5
each item on a crescent scale. After that a total was
calculated for each formulation and plotted on figure 7.
FIGURE 7
Points
ORIGINAL
AIR
OIL
36
30
24
18
12
6
AA
AB
AC
AD
AE
AF
AG AH
AI
AJ
AK
AL
AM AN
AO AP
AQ
POINTS - PRIOR & AFTER AGING
Considering we assumed crescent points, the smallest the
total points the better are the overall properties of the
vulcanization system formulation. Even though, it is still
difficult to notice in figure 7 which is the “best” result.
On figure 8 is plotted the sum of the 3 curves in figure 7.
FIGURE 8
130
Points
120
110
100
90
80
AA AB AC AD AE AF AG AH AI
AJ AK AL AM AN AO AP AQ
TOTAL POINTS - ORIGINAL & AFTER AGING
CONCLUSIONS
• There is not a single system that is able to maximize all
the important properties at the same time.
• The AC system, composed of MBTS-SULFUR-TMTD (2,0-0,4-1,0),
presented the best properties, according to the point system
created.
• The system with peroxide, presented a high elongation at
break.
• It is important to stress, that the vulcanization system
is not the only item responsible for the properties of the
final artifact. Therefore, with different formulations the
results may differ from those herein presented, however, the
trend should be the same.
NITRIFLEX S.A. INDÚSTRIA E COMÉRCIO – Based on a paper presented at :
EXPOBOR 96- October, 15 to 18 1996 - São Paulo - SP- BRASIL