Note: Descriptions are shown in the official language in which they were submitted.
` 1~2128~
METAL AND COMPOSITE MATERIAL
MADE OF THE METAL AND RUBBER
The present invention relates to a metal and a
composite material made of the metal and rubber for tires,
hoses, conveyor belts, or the like and more specifically a
metal and a composite material which exhibit a high adhesion
between metal and rubber.
It is a well-known practice to embed various kinds of
reinforcing materials in rubber to improve its strength and
durability. A composite material made of rubber and metal
is particularly applied to automotive tires, high-pressure
rubber hoses, conveyor belts or the like and is expected to
meet many quality requirements. Among them, it is a very
important requirement to increase the adhesion between the
rubber and the metal in a composite material to improve its
durability.
This requirement is particularly strong with a steel
radial tire in which are used steel cords plated with
copper-zinc (brass) binary alloy as a reinforcing metal.
With the expansion of highway, such a tire is expected to
reveal high durability and high stability while running at
high speed. For this purpose, it is very important to
improve the adhesion between steel cord and rubber. In
particular, a large-sized steel radial tire for trucks and
3~
,~
., , -,-,, . :
.... .
" 1~2128~
buses is strongly required to maintain good adhesion for a
prolonged period of time, since such a tire is used ater
repairing its tread portion once or even twice.
When the rubber in a composite material is vulcanized,
the copper in the plating on the steel cords reacts with the
sulfur in the rubber to form a sulfide at the interface
between the steel cords and the rubber, thus adhering them
together. Various trials have been made to improve the
plating on the metal and the rubber in the composite
material to increase the adhesion between the metal and the
rubber. As a result, the adhesion after vulcanization, that
is, the initial adhesion is being improved. But the initial
adhesion tends to decrease gradually as the material is
exposed to severe conditions during the service life. Thus,
the adhesion durability has not yet reached a sufficient
level. Therefore, the prior art composite materials have
still much to be improved.
If the adhesion between the rubber and the steel cords is
insufficient, the adhesion might be broken owing to heat
accumulation due to hysteresis loss of rubber while the tire
is rotating, causing what is called the separation between
the steel cords and the rubber, thus prohibiting the tire
from rotating any more.
Further, if the tire gets damaged in its tread or side
wall and the damage is so deep as to reach the steel cords,
.
132128~
moisture might infiltrate into the tire through the damaged
portion, vaporize by heat generated while the tire is
rotating, and invade into between the filaments of the steel
cords to break the adhesion between the steel cords and the
rubber, inducing the aforementioned separation. If the air
in the tire contains moisture, it might infiltrate the inner
liner to attack the steel cords, thus causing separation in
the same manner as described above.
Various methods have been proposed to increase the
adhesion between the rubber and the steel cords in a radial
tire in order to avoid such a phenomenon.
One of such methods is to modify the composition of the
rubber covering the steel cords. It was found out in 1950's
that the adhesion between the rubber and the steel cords can
be improved by adding a cobalt salt of an organic acid into
the rubber. The optimum type and quantity of the cobalt
salt have been investigated in various trials since then.
Japanese Unexamined Patent Publication No. 60-424g0 teaches
to optimize the quantities of sulfur and cobalt salt of an
organic salt in order to improve the adh`esion. Another
approach has been to use an HRH series composition
containing silica, resorcin and hexamethylenetetramine.
However, if the rubber material contains an excessive
amount of cobalt salt of organic acid, the quality of
unvulcanized rubber might deteriorate and the adhesion might
degrade as a result of long or h~ e~e~rature vulcanization
or heat aging after long operation. Especially with an HRH
series rubber composition, there might arise such problems as
environmental contamination or rubber scorching in the
production.
Another method is to improve the plating on the
steel cords. For example, Japanese unexamined patent
Publication No. 55-050486 published April 12, 1980 and
Japanese unexamined patent Publication No. 55-105548 published
August 13, 1980 and U.S. Patent No. 4,226,918 propose to use a
ternary alloy plating comprising brass and nickel. However,
the ternary alloy plating on the steel cords tends to get
damaged during wire drawing because oE its poor workability.
Also, the addition of nickel decreases the initial adhesion
between the rubber and the steel cordsO Thus, this method has
not yet been put into practical use. On the other hand, if
the content of additives in the rubber such as cobalt salt of
organic acid, silica, resorcin and hexamethylenetetramine is
reduced to a small amount or zero in order to improve the
quality of characteristics of the rubber or to avoid the
production problems, the decrease in the initial adhesion due
to the addition of nickel to the plating will be marked.
The problem with the drawing of tbe steel cords
rnight be solved by improving the drawing conditions such as
the shape of a dice and the lubricant used. But no
countermeasure has been taken to the problem of decrease in
- . . ~ ,: . .
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1~2128~
the initial adhesion due to the addition of nickel to the
plating. The problem has to be attacked from the viewpoint
of the compositions of both the plating and the rubber.
It is an object of the present invention to provide a
composite material comprising metal and rubber which is
improved in the adhesion after wet heat aging and adhesion
after heat aging (hereinafter referred to as "wet heat
resistance" and "heat resistance", respectively) without
impairing the initial adhesion or the quality
characteristics of the rubber or causing any production
problems.
In accordance with one aspect of the present invention,
there is provided a metal plated with a copper/zinc/nickel
ternary alloy plating comprising 60 to 75 per cent by weight
of copper, 4 to 14 per cent by weight of nickel and the
remainder of zinc, and the content of nickel being not more
than 4 per cent by weight at the outer surface of the
plating, increasing gradually with depth from the outer
surface to the depth of 50 angstroms, and being about 4 to
14 per cent by weight in the deeper area.
In accordance with another aspect of the present
invention, there is provided a composite material produced
by vulcanizing to adhere to the metal as claimed in claim l
a rubber comprising lO0 parts by weight of natural rubber or
synthetic isoprene rubber, l to 8 parts by weight of sulfur,
.
., ~ . .
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. .
~2~28~
and either not more than 6 parts by weight of a cobalt salt
o an organic acid or not more than 20 parts by weight of
silica, not more than 5 parts by weight of resorcin and not
more than 5 parts by weight of hexamethylenetetramine as
an adhesion accelerator.
In accordance with a further aspect of the present
invention, there is provided a composite material produced
by vulcanizing to adhere to the metal as claimed in claim 1
a rubber comprising 100 parts by weight of natural rubber or
synthetic isoprene rubber, 3 to 6 parts by weight of sulfur,
not more than 0.5 part by weight of a cobalt salt of an
organic acid as an adhesion accelerator, and 0.5 to 2 parts
by weight of N-tert-buthyl-2-benzothiazolil sulfenamide or
N-oxydiethylene-2-benzothiazolil sulfenamide as a
vulcanization accelerator.
Other features and objects of the present invention
will become apparent from the following description taken
with reference to the accompanying drawings, in which:
Fig. 1 is a graph showing the range of nickel content
in the copper/zinc/nickel ternary alloy platiny according to
the present invention; and
Fig. 2 is a graph showing the results of measurement of
the nickel contents in various kinds of copper/zinc/nickel
ternary alloy platings.
A: present invention (specimen 3)
,., ~ : :
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132~28~
B: comparative example (specimen 4)
C: present invention (specimen 10)
D: comparative example (specimen 11)
The copper/zinc/nickel ternary alloy plating formed on
a metallic material improves the surface layer of the
plating to prevent the initial adhesion from dropping due to
the addition of nickel and to improve the heat resistance
and the wet heat resistance. The entire plating is composed
of 60-75 per cent by weight of copper, 4-14 per cent by
weight of nickel and the remainder being zinc. The plating
and heat-diffusing conditions are optimized and the plated
metal is subjected to wire drawing so that the nickel
content will be minimum at the outer surface of the plating
and increase gradually with depth. Specifically, the nickel
content is controlled so that it will be not more than 4 per
cent by weight at the outermost surface of the plating,
increase gradually with depth up to the depth of 50 A, and
be kept within the range of about 4-14 per cent by weight in
the deeper area.
According to the present invention, the nickel content
at the surface layer of the plating is limited within the
range as shown by the shadowed area in Fig. l. This is the
result of analysis by the Electron Spectroscopy for Chemical
Analysis (ESCA) in which the plating is sputtered with argon
ions to analyze the content distribution of copper, zinc and
- - ~ ,, .
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! . . . ~ . ~ . '
~32128~
nickel in the plating in the direction of its depth. The
feature of the present invention consists in that as shown
in Fig. 1, the nickel content in the outer surface area of
the plating gradually increases with depth. In the area
deeper than 50 A from the plating surface, the nickel
content is set at about 4-14 per cent by weight and may be
distributed uniformly or may increase or decrease with
depth. The nickel content as used herein is indicated in
weight per cent, converted from the atomic per cent which
is calculated from the analysis intensity of copper, zinc
and nickel.
There was a problem that the addition of nickel to the
conventional brass plating decreases the adhesion reaction
with rubber and thus the initial adhesion. On the other
hand, it has an advantage of increasing the wet heat
resistance and the heat resistance. It follows from this
fact that in order to improve the initial adhesion as well
as the wet heat resistance and the heat resistance, one
solution is to form the surface layer of the plating, which
has an influence on the initial adhesion reaction, of
nickel-free brass and form the inner layer of ternary alloy
comprising copper, zinc and nickel. But it is difficult to
produce a metallic material having two different kinds of
plating layers.
The copper/zinc/nickel ternary alloy plating produced
. . :
.. . . .
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~32128~
by the method described below has a good initial adhesion
because the nickel content at the surface layer having an
effect on the initial adhesion reaction between metal and
rubber is small due to the fact that the nickel content in
the plating surface layer has such a gradient as defined in
the present invention and that the rubber according to the
present invention is combined with the plating. Although
the wet heat resistance and the heat resistance are affected
by the corrosion reaction in the plating layer and the
progress of adhesion reaction, since the plating layer
contains a fairy large amount of nickel, the corrosion
reaction and the adhesion reaction can be effectively
suppresed, thereby improving the wet heat resistance and the
heat resistance.
One feature of the present invention consists in that
the surface layer of the copper/zinc/nickel ternary alloy
plating is improved to increase the initial adhesion as well
as the wet heat resistance and the heat resistance. The
prior art ternary alloy plating technique fails to disclose
the concept of increasing the initial adhesion by improving
the composition of the surface layer of the plating.
It will be described below why the composition of the
plating is defined. The nickel content in the surface area
of the plating is limited to not more than 4 per cent by
weight because if over 4 per cent the initial adhesion will be
,- ...
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,
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1~2i28~
low. Further, the range where the nickel content gradually
increases with depth from the plating surface is limited to
o o
the depth of 50 A. If less than 50 A, the initial adhesion
would be unfavorably affected.
The copper content in the plating is limited within the
range of 60-75 per cent by weight. If it is less that 60
per cent by weight, the adhesion reaction between the copper
in the plating and the sulfur in the rubber will be too
scarce to obtain a high initial adhesion. If over 75 per
cent by weight, the reaction would progress excessively
especially during use of the tire, thereby considerably
lowering the wet heat resistance and the heat resistance.
The nickel content is limited within the range of 4-14
per cent by weight. If less than 4 per cent by weight, the
nickel would be insufficient to increase the heat resistance
and the wet heat resistance, though the initial adhesion is
good. If more than 14 per cent by weight, the nickel
content in the surface area could not be suppressed to less
than 4 per cent by weight. This will unduely affect the
initial adhesion.
Next, it will be described how the metal covered by the
copper/zinc/nickel ternary alloy plating according to the
present invention is produced. There are two ways for
orming the plating layer. One is to put a plating of one
layer upon another in any of the orders listed below,
~321~8~
followed by heat diffusion.
copper plating ~ nickel plating ~ zinc plating
copper plating t zinc plating ~ nickel plating
zinc plating ~ nickel plating ~ copper plating
copper plating ~ zinc/nickel binary alloy plating
The other way is to perform a copper/zinc/nickel
ternary alloy plating in which three elements are deposited
simultaneously, without heat diffusing~ -
In the latter method, the control of the plating bath
is very difficult in order to stably obtain a desired
composition of the plating. Such a method is thus not
practical Also, since the composition of the plating
obtained in this method is uniform from its surface to deep
inside, if the nickel content is over 4 per cent by weight,
the initial adhesion will be poor.
In the former method in which plating and heat
diffusion are combined, it is important that each element be
readily diffused to adjacent layers to form a ternary alloy
plating. But heat diffusion is more difficult to occur
between copper and nickel than between copper and zinc or
between nickel and zinc. Thus if the copper layer and the
nickel layer are adjacent to each other, the heat diffusion
at high temperature or for a long time will be required.
Such a method is therefore not practical, either. Further,
if a zinc plating is directly formed on a steel wire, a hard
11
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.
.;
~2~2~
and brittle iron-zinc alloy phase tends to form at the
interface between the steel wire and the zinc layer during
heat diffusion. This phase might cause the plating to peel
off the steel wire during the wire drawing after plating and
heat diffusion.
Thus, in order to form a copper/zinc/nickel ternary
alloy plating layer, any of the following steps, followed by
heat diffusion; should be taken:
copper plating ~ zinc plating ~ nickel plating
nickel plating ~ zinc plating ~ copper plating
copper/nickel binary alloy plating ~ zinc plating
copper plating ~ zinc/nickel binary alloy plating
zinc/nickel binary alloy plating ~ copper plating
nickel plating ~ copper/zinc binary alloy plating
copper/zinc binary alloy plating ~ nickel plating
Among them, the methods using copper/nickel or
copper/zinc binary alloy plating are not preferable because
not only is it difficult to suitably control the plating
bath, but also a cyanide bath has to be used which can cause
a public pollution problem. Thus, the first, second, fourth
and fifth methods ar preferable.
Next, we shall discuss the method of forming a ternary
alloy plating having such a nickel content grandient at the
surface layer as to increase gradually with depth from the
surface of the plating. With the second and fifth methods,
" . , . , , , ~ .
. . , . . j . . . . .
~3~2~
the plating according to the present invention can be
obtained by suitably setting the heat-diffusing temperature
and time. With the first and fourth methods, the ternary
alloy layer is formed by heat diffusion and simultaneously,
the zinc and nickel in the outer surface layer tend to be
oxidized, thus forming an oxide layer. But, because of its
poor workability, most part of the oxidized layer will peel
off by subjecting the metallic material to wire drawing
after heat diffusion. The nickel content at the surface
layer of plating after wire drawing can be adjusted so as to
decrease from the inside of plating toward surface and have
a content gradient by controlling the heat diffusion
conditions to form an oxidized layer at the surface and by
controlling the wire drawing conditions to peel the oxidized
layer. Thus, the plating layer according to the present
invention is obtained by optimizing the heat diffusion
conditions and the wire drawing conditions. These
conditions depend on the plating method and the thickness
and composition of the plating.
According to the present invention, the metallic
material plated with the copper/zinc/nickel ternary alloy
should have a diameter of 0.1-l.O mm after wire drawing with
the plating layer having a thickness of 0.05-0.50 micron.
The drawn wire may be used as it is or may be shaped into a
cord, wire gauze or fabric. When stranding a plurality of
13
'
132~ 285
such drawn wires into a double-layer cord having a core
layer and an outer layer or into a triple-layer cord having
a core layer, an intermediate layer and an outer layer in
such a manner that some of the wires are in contact with the
surrounding rubber while the others are not, only those in
contact with the rubber may be plated with copper/zinc/nickel
ternary alloy layer according to the present invention while
plating the others with copper, zinc or copper/zinc binary
alloy.
Next, the composition of rubber used in the present
invention will be described. The adhesion between rubber
and metal is influenced not only by the composition of the
plating on the metal but also by that of the rubber.
Therefore, the composition of rubber is important for good
adhesion therebetween.
Natural rubber or synthetic isoprene rubber is used as
the basic component of rubber and sulfur is added to
vulcanize the rubber and also improve the adhesion with the
plating layer covered on the metal surface. The content of
sulfur should be 1-8 parts by weight in relation to 100
parts by weight of natuxal rubber or synthetic isoprene
rubber. If it is less than 1 part by weight, the adhesion
reaction with the plating layer will be too scarce to obtain
a satisfactory initial adhesion. If over 8 parts by weight,
the rubber will react excessively with the plating layer.
14
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132~28~
This will lower the adhesion, especially the heat
resistance, and unfavorably affect the physical properties
of the rubber.
As an adhesion accelerator, a cobalt salt of organic
acid, or silica, resorcin and hexamethylenetetramine may be
added. As a cobalt salt of organic acid, cobalt
naphtherate, cobalt stearate, cobalt oleate, and cobalt
maleate may be used. The cobalt cotent should preferably be
8-10 per cent by weight in cobalt salt of organic acid. The
content of the cobalt salt of organic acid should be less
than 6 parts by weight. If it is more than 6 parts by
weight, it will have a remarkably bad effect on the physical
properties of the rubber after heat aging during use. When
adding silica, resorcin and hexamethylenetetramine, the
upper limits of their contents are defined because too much
amount over the upper limit will decrease the wet heat
resistance and have a bad effect on the physical properties
of rubber.
However, preferably, such adhesion accelerators should
not be added at all or limited to a small amount because not
only the addition tends to lower the quality characteristics
of the rubber and cause production problems but also
increase the production cost of the rubber product. As to a
cobalt salt of organic acid, it has heretofore been believed
to be necessary to add over 0.5 part by weight to o`otain a
,, .
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~, ,
~32128~
good initial adhesion. With the copper/zinc/nickel ternary
alloy plating according to the present invention, the
initial adhesion is improved even if a cobalt salt of
organic acid exists a little or does not exist at all in the
rubber. In order to further improve the initial adhesion,
the rubber composition has been improved.
Namely, the rubber should contain no more than 0.5 part
by weight of cobalt salt of organic acid to 100 parts by
weight of natural rubber or synthetic isoprene rubber. This
rubber material also contains 3 to 6 parts by weight of
sulfur and 0.5 to 2 parts by weight of a vulcanization
accelerator such as N-tert-buthyl-2-benzothiazolylsulfenamide
or N-oxydiethylene--2-benzothiazolylsulfenamide. If the
content of the vulcanization accelerator is less than 0.5
parts by weight, the vulcanizing speed will be slow, thus
deteriorating the adhesion. If it is over 2 parts by
weight, the modulus of the rubber will grow excessively,
thus lowering the adhesion and the breaking strength of the
rubber itself.
The copper/zinc/nickel ternary alloy plating layer has
such a nickel contefft as to gradually increase with depth
from its outer surface. ~-ith this arrangement, when the
plating is adhered by vulcanization to the rubber material
made of natural rubber or synthetic isoprene rubber and
containing or not containing a cobalt salt of organic acid,
16
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: , : .: : . . .
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~32128~
or silica, resorcin and hexamethylenetetramine, the initial
adhesion will not be impaired and the adhesion after long
use will be kept high. Thus, the composite material
according to the present invention, which comprises metal
plated with copper/zinc/nickel ternary alloy and adhered to
rubber, has an excellent wet heat resistance and heat
resistance while keeping a good initial adhesion.
In the following Examples, reference numbers without
dash are used for steel cords to designate Comparative
Examples and Examples according to the present invention and
reference numbers with dash are used for combinations of
rubber and steel cords, that is, tires to designate their
Comparative Examples and Examples according to the present
invention.
EXAMPLE 1
A plurality of 1 x 5 x 0.25 mm dia steel cords plated
with copper/zinc/nickel ternary alloys and steel cords (of
the same sizel plated with copper/zinc binary alloys were
used. Their average compositions of plating are shown in
Table 1. The nickel content distributions for Examples 3
and 10 according to the present invention and Comparison
Examples 4 and 11 were measured by means of ESCA. The
results are shown in Fig. 2. Table 2 shows the compositions
17
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'. . ~ .; :
'
~ 32~ 28~
of three rubber materials used in this example.
The steel cords and the rubber materials were adhered
together by vulcanizing at 150 C for 30 minutes and the
composite materials were tested for adhesion in accordance
with ASTM D2229-80. The pull-out length was 10 ~m and the
pull-out force was the average value of 15 pull-outs. The
examples were tested for the initial adhesion and the wet
heat resistance which was determined after subjecting them
to wet heat aging at 80 C and 95 ~ RH for 10 days or at 120
C steam for one day. The results are shown in Table 3.
As shown in Table 3, the steel cords in Examples 3, 5,
6, 10, 12 and 13 according to the present invention, which
are plated with copper/zinc/nickel ternary alloys, exhibited
far better initial adhesion than the steel cords in
Comparison Examples 4, 7, 11 and 14 which are plated with
copper/zinc/nickel ternary alloys. It is apparent from
Table 3 that the steel cords according to the present
invention has much better wet heat resistance than the steel
cords in the Comparison Examples 1 and 8 which are plated
with copper/zinc binary alloys.
EXAMPLE 2
The rubber materials having a basic composition shown
in Table 4 were adhered to 1.5 x 5 x 0.25 mm dia. steel
18
. ~, . . .
. : - , -
"
.
~32~2~5
cords having average plating compositions shown in Table 5
to test the adhesion. Test specimens were made by adhering
the rubber materials and the steel cords shown in Tests 1 to
4 by vulcanizing in predetermined conditions. They were
tested for peelability after subjecting them to an aging
under the conditions indicated in Table 6. In these tests,
the peeling force was measured by mechanically peeling the
rubber material from the respective steel cords. Also, how
much rubber is left on the steel cords was evaluated by eye
check and marked on the basis of 10 points~ Larger numbers
indicate better results. In Test 5, tire examples were put
to a running test to check their quality characteristics.
In Test 1, the vulcanizing conditions were examined.
The test results in Test 1 are shown in Table 7. The
adhesion between the rubber materials and the steel cords
according to the present invention were good in terms of
initial adhesion, wet heat resistance and heat resistance in
spite of the fact that the rubber materials contained no
cobalt salt of organic acid.
In Test 2, the relationship between the adhesion
and the vulcanization accelerator in the rubber materials
was evaluated~ The results are shown in Table 8, which
shows that the test specimens containing the vulcanization
accelerator according to the present invention reveals a
good adhesion.
19
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~32~2~
In Test 3, the relationship between the adhesion and
the contents of the cobalt stearate and sulfur in the rubber
materials was evaluated. The results are shown in Table 9,
which shows that the initial adhesion as well as the wet
heat resistance and the heat resistance are good if the
content of cobalt salt of organic acid is less than 0.5 part
by weight and the sulfur content is 3-6 parts by weight.
In Test 4, the relationshlp between the adhesion and
the contents of the nickel in the plating and the
vulcanization accelerator in the rubber was evaluated. The
results are shown in Table 10. When the nickel content is 4
to 14 per cent by weight and the content of the
vulcanization accelerator is 0.5 to 2 parts by weight, the
initial adhesion, wet heat resistance and heat resistance
were good.
In Test 5, the composite materials according to the
present invention and those in the Comparison Examples were
made into tires and subjected to a running test to check
their quality characteristics. The results are shown in
Table 11, which reveals that the tires according to the
present invention having a steel breaker made of the steel
cords and the rubber materials containing no or less amount
of cobalt salt of organic acid has extremely good quality
characteristics.
. . : :, , . ~: " ,
- . : . ,". " .......
.
132~28~
TABLE I
\ Component r Copper ¦ Zlnc r Nickel
steel cord \ ¦ (wt %) ¦ (wt %) ¦ (wt %)
.
COM. EX. 1 65 3
COM. ex. ¦ 2 ¦ 65 ¦ 33 ¦ 2
EX. 3 ¦ 63 ¦ 31 ¦ 6
COM. EX-. ¦ 4 ¦ 63 31 ¦ 6
EX. ¦ 5 ¦ 63 ¦ 27 ¦ 10
¦ EX. ¦ 6 ¦ 63 ¦ 23 ¦ 14
COM. EX. ¦ 7 ¦ 64 ¦ 18 ¦ 18
COM. EX. ¦ 8 ¦ 70 ¦ ~0 ¦ O
COM. EX.¦ 9 ¦ 70 ¦ 28 ¦ 2
¦EX. ¦10¦ 71 ¦ 23 ¦ 6
!COM. EX-~11¦ 70 ¦ 24 ¦ 6
EX. ¦ 12 ¦ 71 ¦ 19 ¦ 10
EX. 113l 71 1 15 L 14
¦ COM. EX. ¦14~
EX. stands for Example of present invention.
COM. EX. stands for Comparative Examp]e.
. ~
13~12~
TABLE 2
.
_ _
Kind of
\ rubber A B C
Component
. ..
Natural rubber 100 by wt ¦ 100 bPyartt ¦ 100 PbartS
Zinc oxide 10 ~ 0 ~r ¦ 10
_.
Stearic acid 1 ~
Carbon blac~ (HAF) ¦ 50 ~ ¦ 40 ~ ¦ 50 ~
..
Antioxidant (*1) 2 ~ 2 ~ 2 ~
_
Sulfur 5 ~ ¦ 5 ~ ¦ 5 ~
_
Vulcanization (*2)
accelera~or DZ
. .. . . ..
Cobalt naphthenate 2 ~ " ¦ "
Resorcin ¦ O ~ ¦ 2 ~
I Silica ! o lo o
¦ Hexame~
*1) 2, 2, 4-trimethyl-1, 2-dihydroquinoline polymer
*2) UZ:N, N'-dicyclohexyl-2-benzoth~azolylsulfenamide
22
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X' _ r~ ~i C`~ ~ ~ ~ ~ 1 ~3 C7
_ o o
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I ox ~
. o _ e e c e e t O ¦ O
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. . . _ c c e e
0'~ 1 cn ~
, ___ _ I _ I I
I ~ ¦ e ~ ¦ e
OX I C" I O I1 ~3 1 ~3 1 1 1 1 1
e j e
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E-~ ~ I t ~ I _ _
3 O O
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132128~
TA~LE 4
Componen~ ¦ Part
Natural rubber 100
Carbon black (HAF) 50
Zinc oxide 8
Antioxidant (*5) 2
Cobalt stearate (*6) Variable
(Stearic acid) (1. 23
Sulfur Variable
Vulcanization accelerator Variable
*5) 2, 2, 4-trimethyl-1, 2-dihydroquinoline polymer
*6) Cobalt content 9~
24
,, - , ~ ~ ,
,: : -
- , , ~ ~ :
, . . .
~32~
TABLE 5
~ \ o~ponent ~ Copper 1 Zinc ¦ Nicke1
Kind of ~ (wt %) (w~ %) (wt %)
steel cord \ I
COM. EX. ¦15 1 6~ ¦ 35 0
COM. EX. ¦ 16 ¦ 6~ ¦ 33 ¦ 2
EX. Il7L6~ 1 31 1 4
. EX. ¦ 18 ¦ 6~ ¦ 29 ¦ 6
COM. EX. ¦19 ¦ 6~ ¦ 29 ¦ 6
EX. I 20 1 65 ! 27 1 8
EX. ¦ 2~ ¦ 6~ ¦ 25 ¦ 10
ex. ¦ 22 1 6~ ¦ 23 ¦ 12
EX. ¦ 23 ¦ 6~ 21 ¦ 14
COM. EX. ¦ 2~ 1 6 19 1 '6
COM. EX. ¦ 25 1 6~ 17 ¦ 18
COM. EX. ¦ 26 ¦ 6~ ¦ 15 ¦ 20
COK. EX. ¦ 21 ¦ 6~ ¦ 13 ¦ 22
..
.. . ~ ~ ~ . . .
i ' ;'' ':~'; '' ' '' ''' '` ` ' ' '
~, ; , ,. :.
" . . ..
" . ~ :
132~ 28~
TABLE 6
i . Aging Agin8 . Aging
` \ Item temperature (relat-ve time
Aging \ humidity)
conditions \ ~ C~ ________~ ~h r~
(a) _ _ ¦ O
_ _ ._ . _
tb) 80 95 400
. _ . .. _ _ _ . _ . .
(c) 120 lU0 24
__ ... __ .
I (d) 120 ___ _
26
: . ;
, , ,
~32128~
(Tes~ 1) Evaluation of Vulcanizing Condieions
Rubber composition Steel cord conditions
Part
by wt
Natural rubber 100 EX. 1~ 170 c - 10 min.
Carbon black (HAF) 50 COM. EX. 19 lS0 c - 30 min.
Zinc oxide 8
Antioxidant 2
Cobalt stearate O
Stearic acid 1.2
Sulfur 5
Vulcanization accelerator NS (*7)
*7) NS : N-tert-buthyl-2-benzothiazolylsulfenamide
TABLE 7
Kind of _
\ \ steel cord
Vulcan- \ \EX. 18 COM. EX. 19
izing \ Aging
conditions `~onditions ~ _
170C-10 min. (a) 10 pointS 10 points
(b) 10 " 10 ~
(c) 10 ~ 9
(d) 10 " 10
150'C-30 min. (a) 9 ~ 6 ~
9" 7
(c) 10 ~ 7 ~
(d) 10 " 7 ~ ¦
.. _ _ 1
27
,:. ., : ,. - :
..
. , :
, ~ - : ~ :
.
~32~28~
(Test 2) Evaluation of Vulcanization Accelerator in Rubber
Rubber composition Steel Vulcanizing
cord condition
Part
by wt
Natural rubber 100 EX. 18 150 c - 30 min.
Carbon black (HAF) 50
Zinc oxide 8
Antio~idant 2
Cobalt stearate
Stearic acid 1. 2
Sulfur 5
Vulcanization accelerator
(Kind changed)
TABLE 8
nd of vulca- _ _ _ _ _ .
Aging ~ aCcie~e- COM. EX. EX. EX. COM. EX.
conditions ~ DZ MOR (*8) NS CZ (*9)
.... __ .. ... ___ ---
(a) 6 poln~s¦ 10 poines ¦ 9 points 7 points
(b) 6 points¦ 9 points 9 points ¦ 8 points
. . .
(c) 8 points¦ 9 points lo points 8 points
(d) 7 poiDes¦ 10 points ¦~o points ¦ 7 poi~ts
*8) MOR : N-oxidiethylene-2-benzothiazolylsulfenamide
*9) CZ : N-cyclohexyl~2-benzothiazolylsulfenamide
-, . : . : . . ' ,, : '
~321285
(Test 3) Evaluation of Contents of Cobalt Stearate and Sulfur in Rubber
Rubber composition cor3l condition g
Part
by wt
Natural rubber 100 E~. 18 150 ~ - 30 min.
Carbon black (HAF) 50
Zinc oxide 8
Antioxidant 2
Cobalt stearate Variable
( Stearic acid Variable)
Sulfur Variable
Vulcanization accelerator NS or NOR
Combination for Composite Naterials
7 ~ 3' 9' 15'
6 ~ 6' 12'
~5 -2' 8' ld~'
o~
~ 4-- S' 11'
-
3 1 7 13
,
u~ 2-- 4' 10'
l L ~
0 0 ~ 2 . 0
Cobalt stearate (parts by wt)
: . ::. : ~ ~ :
.,
: . . .: .: :
,
~2128~
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:, . !.
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'~ ; , , , . ' :
~32128~
(Test 4) Evaluation of Content of Nickel in Plating and Content of Vulcanization
Accelerator in Rubber
Rubber composition Steel cord Vulcanizing
Part condition
by wt
Natural rubber 100 EX. 17~ 18~ 20~23 150 c - 30 min.Carbon black (HAF) 50 CO~.E~ 16~ 24-~27
Zinc oxide 8
Antioxidant 2
Cobalt stearate 0
Stearic acid 1.2
Sulfur 5
Vulcanization accelerator NS or ~OR Variable
Combination of Nickel Content and
Vulcanization Accelerator Content
D
3 . 0 - 18' 24~ 30' 36~ 42' 48~ :
2.5 ~ 21' 27' 33' 39' ~15' ~1'
2 . O 17' 23' 29' 35' ~1 ' 47'
~a 1 . 5 ~ 2~' 26 ' 32' 38 ' 44 ' 50
~,
1 . 0 ~ 16 22 28 34 40 46
, O . ~ - 19' 2~' 31 ' 3 ~ 3 ' 49'
I ' ' I
0 2 4 6 8 10 12 14 16 1~ 20 ~
Nickel content (wt ~)
31
/
. : : - : : .. :
- : . . :
.
~32128~
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