Note: Descriptions are shown in the official language in which they were submitted.
~5~3~
~lWC-203~
-- 1 --
FLAME RETARDANT WIRE WITH
HIGH INSUL~TION RESIST~NCE
.
BACKGROUND OF THE INVENTION
The present invention relates to compositions which
have .improved insulation resi~tance stability and to
methods of preparation thereofO More specifically, the
invention relates to compositions which have improved
i.nsulation .resistance stability in water so that compo-
sitions can be employed in forming insulation layers
which are thinner by a substantial amount than previous
i.nsulations and yet provide adequate or improved degrees
of insulation resistance stability.
A number of compositions are known which have
relatively high insulation resistance stability. Among
such compositions are the crosslinked polyethylene
compositions prepared generally according to the
teach.in~s oE the Gilbert and Procopio U.S. Patent No.
lS 3~079,370 dated Fehruary 26, 1963, and U.S. Patent No.
2,888,442 to Uraneck et al dated May 26, 1959.
It i.s known that particular properkies, such as
Elame xetardancy, electrical properties and moisture
resistivities, etc., are of great signi.ficance duri.ng
the actual course of application of polymeri.c materials
in the field. A number of compos.itions are known which
have relatively high flame retardancy properties. Among
such compositions are the ones which employ highly
effective commercial halogenated flame retardant additives.
6 ~
5~3~
41WC-2037
-- 2
However, the utili~ation of halogenated flame retardan-ts
in the polymeric materials introduces a high level of
polarity into the polymeric materials. The introduction
of highly polarized material into the insulating poly-
meric compositions has long been known to have severelydeterimental effects upon the electrical properties, such
as insulation resistances and dielectric strength. Such
detrimental e~fects have been accentuated where -the poly-
mer compositiolls containing highly polarized material
:L0 has been used in wet locations. This is because the
presence of the highly polaxized ingredient in a polymeric
composition has effectively induced absorbtion of moisture.
Accordingly, the presence of a highly polarized ingredient
in an insulating polymeric composition has precluded long
term use of such insulating composition in moist or wet
environments. Improvements in the insulation resistivity
and resistance to moist environment have been made over a
period of time for halogenated compositions. Among such
compositions are the ones prepared generally according to
the teachings of the ~etts and Holub U.S. patent number
No. 4,209,566 dated June 2~, 1980.
Although such compositions are highly satisfactory
and represent an advance in the art, as the needs of the
industry change with time, there comes times when still
Eurther improvements in the insulation resistance stability
o~ such insulating compositions are desired and needed.
Recently, in particular, there has been a need for
providing wire and cable with reduced volume of insulation
as the cost of the polymer ingredients have greatly
increased. Also~ as equipment iIl which wire has been
employed has grown smaller, the need for reducing the wire
volume in such equipment has increased.
For example, in a control cable; if a wire insulation
thickness is reduced from 30 mils to 20 mils~ then the
wire diameter is actually reduced ~y 20 mils due to the 10
3~
~l~C-2037
-- 3 --
mil reduction on each insulatiny sidewall of the wire.
~here a number of such wires are grouped in a control
cable, the 20 mil diameter reductions are added for
each wire across one diameter of the cable. For example,
where seYen wixes are bundled in a control cable there
are essentially three wires across one diameter of -the
cable, one wire at the center and six wires grouped
about the single center wire. For such as cable, the
reduction in diameter is about 60 mils for the diameter
of the ~ire bundle. In addition, an outer jacket will
have a smaller dia~eter because of the smaller diameter
bundle which it contains.
OBJECTS OF THE I~VENTION
. . . _
One object of the present in~ention is to provide
novel insulation compositions which make possible reduction
in the thickness of a deposited layer of insulation
without loss of important electrical properties such as
the insulation resistance stability~
Another object is to provide a ~ethod of forming such
novel wire and ca~le products insulated therewi-th.
Still another object of the invention is to provide
wire insulated with compositions which have improved in--
sulation resistance stability.
Another object is to provide insulate~ wires which
have relati~ely thinner layers of insulation but which
have properties which are equal to or superior to
insulation layers of thicker dimensions~
Another object of this invention is to pro~ide
methods for forming such insulated articles~
Another object is to provide a composi-tion particularly
suitable for use in insulating cables to be employed in
damp and wet locations, including wet locations which are
at elevated temperatures~
Another object is to provide a composition as in -the
prior object for insulating power cables for use in wet
~5~
41WC 2037
- 4
locations including use at elevated temperature in wet
locations.
Another object is to improve the insulation resistance
stability of compositions which contain highly polar
organic flame retardants.
~ nother object is to provide compositions having
improved insulation resistance stability.
Another object is to provide articles insulated with
compositions having improved insulation resistance stabi]ity.
Another object is to provide crosslinkable composi-tions
having improved insulation resistance stability.
Other objects will be in part apparent and in part
pointed out hereinafter.
BRIEF STATEMENT OF THE IN~IENTION
Objects of the present invention are achieved by
combining polyolefinbase polymer with polar organic
aditives and by including in the composition antioxidants
which cause surprising increase in the insulation resistance
and in the insulation resistance stability of the resultant
composition. The polar organic additives may be organic
halogenated flame retarclants such as decabromodiphenyl
oxide and the antioxidants may be a zinc salt oE a mer-
captoimidazole and a sterically hindered ditertiary butyl
phenol.
The composition may contain other conventional
additives.
The composition may also be crosslinked and such
crosslinking may be high eneryy radiation such as high
energy electrons or be conventional chemical crosslinking
agents such as organic peroxides.
:~RIEF DESC~IPTIO~l O~ THE FIGURE~
FIGURE 1 is a graph of the test data obtai~ed from
measurement of the insulation resistance of a number of
compositions measured in megaohms against -time indicatecl
as the abcissa in weeks.
3~
~lWC-2037
-- 5 --
FICURE 2 is a perspecti~e view of a wire formed
pursuant to the present inventlon having a central con~
ductor and an insulating layer about the conductor.
FIGURE 3 is a graph of the specific inductive
capacitance and the percent power factor against time in
weeks.
DESCRIPTION OF ~ PREFER.~D EMBODIM~NT
As indicated above, a novel feature of the present
invention is a composition which con-tains a highly polar
additive ~ut which also has a high insulation resistance
as well as a high insulation resistance stability.
The composition itself has a polyolefin base polymer
composition and other ingredients are combined with the
polyolefin base as set out below.
A first ingredient is an organic flame retarclant
which has been the subject of a special treatment pre~
paration procedure~
A treated flame retardant used and useful in practlce
of the present invention is a pretreated composition de-
scribed in essential details in the U.S. Patent Mo.4,209,566
to Betts et al dated June 24, 1980. Such flame retardant
includes both a set of ingredients and a treatment of the
ingredients including an ovenizing treatment. The set
c)f ingredients, as well as their proportionsr are set forth
in Table I below.
A first ingredient of the pretreated ~omposition is
an organic halogenated flame retardant. The organic halo-
genated flame retardant may preferably be the decabromo~
diphenyl oxide or decabromodiphenyl e-ther, but may also
be ethylene bis (tetrabromophthalimide~ sold commercially
under the designation BT 93 by Saytech Corporation, or a
brominated diphenyl oxide of a lower degree of brominationO
In a more general ~ense, the stable organic halogenated
flame retardant may be employed, such as the chlorinated
3~ flame retardant avallable commercially under the trade
5~3~
41WC-2037
-- 6 --
name Dechlorane of ~Iooker Chemical Corporation.
The treated flame retardant also contains antimony
oxide. The antimony oxide flame retardant used in the
treated flame retardant of the present in~ention is the
conventional or standard powdered compound.
The treated flame retardant used and useful in the
present invention also includes a fumed silica in-
gredientO One such fumed silica found useful in preparation
of a suitable trea-ted flame retardant is one sold com-
mercial]y under the designation Cabosil MS7 and available
~:rom C.L. Cabot Inc. of Boston, Ma.ssachusetts.
The treated flame retardant useful in the present
invention also includes a silicone fluid ingredient,
which is a reactive silicone such as is described in the
]5 U.S. Patent 4~209,566 assignea to the same assignee as
the subject application.
Lastly, the treated flame retardant useful in the
present invention is prepared by a heat treatment procedure
which may typically be a baking of the well-mixed ingre-
dients described above at a temperature of about 375F
for a period of 16 hours. Such -treatment and variations
thereof are more fully described in the issued U.S. Patent
~,209,566.
The foregoing is a descrip-tion of each of the ingre-
dient6 of Table I and the Table also sets forth the pro-
portions in which the ingredients may be used as well as
proportions in which they are preferably used.
T.~BLE I
INGREDIENTS IJSEFUI. RANGE PREFERRED R~NGE
Decabromodiphenyl oxide 100 100
Antimony oxide 10-70 20-50
Fumed silica 5-30 10-20
Reactive silicone fluid 0.1-10 3-5
(as descxibed in U.S.
Patent 4,209,566~.
5~3~
- 7 - 41WC-2Q37
The Table I above sets forth the ingredients and
makeup of a special flame retardant additive useful in
combination with polyethylene and other ingredien-ts in
carrying out the present invention.
Consideration is given next to the other ingredients
of the novel compositions of this invention.
Considering first the ingredients as listed in Table
II; the polyole~in as used herein refers to polyethylene
as a preferred component, but -the pol~olefin may also
be copolymers of ethylene, including but not limited to
ethylene ethyl acrylate, ethy].ene vinyl acetate copolymers,
ethylene-butene copolymers, ethylene-propylene copolymers,
terpolymers and ~uatrepolymers such as EPDM. Also, the
polyolefin may be either of the high density or the :low
density pol.yeth~-~lene or may be polyallomer.
Dibasic lead phthalate composition or ingredient may
be used in the composition of this lnvention and may be
any organic lead compound in which the lead proportion
is roughly equivalent to that of the dibasic lead phthal.ate
or greater. For example, other organic lead compounds
which have low volatility and which result in suitable
stabilization properties may be employed but -the dibasic
lead phthalate is the preferred compound for thi.s ingred:ient.
By stabilization is meant that the lead compound can scavenge
free halo~en fxom the composition.
Silicone gum can be used as an optional ingredient
and is accordingly incl.uded as such i.n Table II below, as
is the dibasic lead phthalate. The silicone gu~ useful
in the novel composition o~ this invention is described in
30 Canadian Patent No. 1,110,789, issued October 13, 1981
to Betts et al. The benefits pointed out in the above~
mentioned Canadian patent 1,110,789 will be obtained
in reference to the composition oE -the present invention.
The peroxide curing agent as indicated may be an
41WC-~037
8 --
organic peroxide which decomposes~ i.e. generates ~ree
radicals, at the elevated temperatures above -the basic
mixing temperatures and may be, as in the examples given,
dicumyl peroxide~ Alternatively, materials sold under the
commercial designation Vul-Cup R may be employed although
the cost is higher than that of the dicumyl peroxide.
Such organic peroxides are known in the art and in the
patent literature directed to this art and are described
in part in the patents referenced above.
The bromine containing treated flame retardant is as
described above.
Other additives conventionally used in polyolefin
base polymer composition used in wire insulation may also
be added and included. For e~ample, conventional fillers,
pigments, curing coagents, and other conventional additives
including preservatives such as modifying agents, mold
release ingxedients, processing aids or lubricants and
the like and commonly employed with polyolefins in addition
to the essential ingredients set forth above and herein-
after such as the pre processed flame retardant and thespecial combination of antioxidants, may be used.
The octamethyltetracyclosiloxane ingredien-t is a
reactive silicone fluid which is commercially available
from General Electric Company at Waterford~ New York,
under the trade designation SC 363~ and is an optional
ingredient in the compositions of -the subject application.
The lngredients o:E Table I are used as a single
pretreated ingred.ient in the combination of ingredients
as set out in Table II below.
~5~3~
~lWC-2037
g
I'ABLE I I
INGRED--IENTS USEFUL RANGE PREFERRED RANGE
Polyolefin 100 100
Bromine containing treated
flame retardant* 5-80 10-70
Dibasic lead phthalate 0-20 1-10
Silicone gum 0-20 1-10
Lead stearate 0-3 02
Octamethyltetracyclosiloxane 0-5 0-3
Triallyl cyanurate 0-5 0-3
Oryanic peroxide 0-8 1-5
Zinc salt of a mercapto-
imidazole** 0.5-15 1-10
Sterically hindered di-
tertiary butyl phenol** 0.5-15 1-10
* An ovenized blend as described above of decabromodiphenyl
oxi.de~ fumed silica and silicone fluid and as set
Eorth in U.5. Patent 4,209,566 to Betts et al dated
June 24, 1930.
* As set forth in U.S. Patent No. 4,260,661 to Walter
et al dated April 7, 1981 and commerciall.y available under
the designation Vulkanox ZM~-2.
*** As set forth in U.S. Patent ~,260,661 and commercially
ava.ilable under the designation Irganox. An example
of an Irganox is Irganox 1010 or Irganox 1035.
. ~...
The results obtained from practice of the present
invention are gi~en with reference to Example 1 and Figure
1.
~5~3~
41WC-Z037
-- 10 --
Where higher temperature insulating compositions are
desired or, in other words, where it is desired to employ
an insulating composition at a higher use temperature,
generally a larger amount o~ the an-tioxidant components
listed in Table II should be employed in the col~ination
of Table II for a higher projected use temperature.
To illustrate, if a use temperature of 125C is
sought, then the ratio or proportion o~ the ZMB-2 ingre-
dient and also the proportion of Irganox ingredient
substantially as set forth in lower ranges of values should
be employed. For still higher temperatures of use of the
insulating compound prepared pursuant to this invention,
employing the antioxidant ingredients o~ the U.S. Patent
4,260,661 at temperatures at and above the order of 150C
or above, some still higher concentration ranges set
forth for the Z~B and the Irganox antioxidants will permit
such higher use temperatures to be achieved.
The peroxide ingredients of the composition may be
omitted and high energy radiation, such as high energy
electrons, can be employed to cause crosslinking and
curing of the coating composition also by methods well
known in the art.
In Eigure 2 7 there is illustrated a central condllctor
12 about which has been formed an insulating layer l~
prepared pursuant to the present invention. The in-
sulating layer 14 may be in the curable state or may
be in the cured state. Also, the cured insulation may be
chemically cured or cured by high energy radiation. The
product illustrated is an insulated conduc-tor lO, the
conductor of which may be solid as illustrated or
stranded.
Refexring now to Figure 3, a set of da-ta resulting
from tests performed on the composition of a sample E of
Table III ~as obtained and the test results are plotted in
the Figure. The abscissa of the plot is time in weeks
3~
41WC-2037
-- 11 --
and it is eviden-t that the tests extended over a period
of about 66 weeksO
Two ordinates are shown. ~he ~irst is -the ~IC, or
specific inductive capacitance, and the second is -the
percent power factor at 80 volts per mil. The scales for
the t-~o sets of tes-ts are different so that al-though the
graphs are plotted relatively close to each other, they
actually correspond to di~ferent values which are values
used for the respective ordinates of the graph. As is
evident from the graphs, the samples were tested at
intervals represented by the dots and, prior to each
such test~ the wire sample being tested was subjected
to a so-called "high pot" test which involved the
imposition o~ a high voltage, of 2.4 kilovolts, to the
conductor of the wire as the insulated portion of -the
wire was immersed in a water bath at a temperature of
75C. The 2400 volt potential existed between the
conductor of the insulated wire immersed in the water and
an uninsulated copper wire which was also immersed in the
water.
From the results which are plotted in Figure 3, it
is evident that the specific inductive capacitance of the
insulation composition of the subject invention gives a
very stable performance with regard to the insulating
composition which insulates the wire and that there is
a rela-tivel~ small change in specific inductive capacitance
over the entire period of 66 weeks during which the
measurements were made. This is in addition to the fact
that the actual specific inductive capacitance overall
value was itsel~ uniquely low for the composition cor-
responding to Test E of Table III.
~ onsidering ne~t the actual graph data for the per-
centile factor~ at the 80 volt per mil potential~ here
again the graph data demonstrates that the power factor
was quite remarkably low for a flame retardant composition
and, in addition, that the power factor remained very stable
3:~
4lWC-2037
- 12 -
and showed essentially no increase overall during the
entire 66-week period of the test.
Based on the foregoing, it is eviaent that the
composition of the present invention is unique in
providing both Elame retardancy in combination with a
unique set of electrical properties of remarkable
stability for an insulating matexial which contains
the type of flame retardan-t which is present in the
subject material.
EXAMPI,E _
In Example 1, a single set o~ the first set of
ingredients, including all ingredients other than
antioxidants, was chosen and the quantities of these
ingredients was constant for all tests performed
including Tests, A, ~I C, D and E. ~he antio~idant
and the antioxidant content were varied. The changes
in antioxidant ingredients and amounts were the only
changes in the compositions A through E. The remarkable
differences in results obtained~ particularly differences
in insulation resistance stability for the relatively
mino:r changes in antioxidant content, are set forth in
graphical form in Figure 1, where individual plots are
labelled ~ through E. These results attest to the
uni~ueness and novelty of the compositions ancl articles of
the present invention.
.~ _ , _ ~ .. ,.. .. ..... _ ~ ... _ .. _ .. .. .. .. ... _ .. _.... , _ __ _ _ ;"
3~
~13~ 'C 2037
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3~
41WC-2037
-- 14 --
Tests of insula-tion resistance and of insulation
resistance stability were performed on each of the five
composition, A through E, listed in Table III abo~e. rrhe
results of the tests which were performed are plotted in
the graphs A through ~ in Figure 1 of the drawings. In
this ~lgure, time in weeks is plotted as the abscissa and
the reslstance in megaohms measured between the conductor
in the wire and the water for 1000 feet of wire in water
at 75C is plotted as the ordinate.
From the plot of the data in Figure 1, it is evident
that an unusual and completely unexpected improvement
in the insulation resistance and in the insulation
resistance stability has been discovered. The improvernent
is shown in the graphs fox the test compositions D and E
of the Example 1, Table III. The plots of Tests D and
E are compared to the graphs for Tests A, B and C which ha~e
the compositions as listed in Example 1, Table III. All
compositions had all ingredients other than the antioxidant
ingredi.ents within the range indicated u~d~r "Parts by
Weight" and precisely the same proportions and amounts
for each of the test samples A through E as indicated by
the designatlon "same". The signifiant diEference in
ingredient content involved only the use of different
ant~oxidants and combinations of antioxidants, and
2~ particularly, the combination of the Vul~anox ZMB and one
of the Irgallox antioxidants. It is evident that a very
dramatic impro~ement in insu:Lation resistance and insultation
resistance stability is demonstrated by Test plots A, B,C,
D and E of Figure 1.
It shouLd be emphasized that the remarkable gain in
i.nsulation resistance stability is the result of providing
a certain and unique con~ination of antioxidants in the
composition and not by inclusion of any ingredient which
might be expected to improve the insulation xesistance
or -the stability of the insulation resistance of -the
3~
41WC-2037
- 15 ~
resultant novel composition. To be more explicit about
the nature and extent of the novel results discovered in
connection with the subject composition, a more detailed
description of the results o~-tained is given here.
Referring now to Figure 1, the da-ta obtained from
tests of the compositions as set forth in Table III is
plotted with the insulation resistance in megaohms dis-
played on the ordinate scale and the time in weeks on
the abscissa scale. The individual curves oE plotted
data correspond to the individual compositions which
are set out in Table III~ In Table III, the test com-
position labelled A through E are marked with the letters
used ~t the head of the column for the data recorded ~ox
the compositions employed. It will ~e understood that
each composition was the same in its constituents and in
the proportions of the constituents, other than the
antioxidants. Specifically, the conventional Agerite and
Santowhite antio~idants as well as the zinc salt of a
me:rcaptoimidazole and the sterically hindered di-tertiary
butyl phenol, were changed as indicated but none of -the
proportions or concentrations of the other ingredients
varied ~rom the composition for Graph A through the
compositlon for Graph E. However, there was variat:ion in
the concentration proportions of the special antioxidants
which were employed and these are set forth in Table III.
The UI--test used in obtainin~ the test data is UL
est g3 ~or Thermoplastic Insulated Wires and Cables~ and
UL Test 44 for Rubber Insulated Wires and Cables.
Turnin~ now to Figure 1~ the insulation resistance
stability for a wire formed with a 1~ AWG internal conductor
and a 3Q mil wall thickness and tested at 75C in water with
60Q volts AC applied are given. The ~irst curve shows -that
the insulation resistance rose from a low value to a
maximum of approximately 13Q0 in a period of 30 to 35 weeks
and that thereafter the insulation resistance declined with
3~
41WC-2037
- 16
the passage of time.
Turning next to the plot for Graph B, the curve is
so marked on the drawing and it is evident that in a
period of about 25 ~eeks~ the curve reached a maximum
value of about 50Q0 megaohms and that thereafter there
was a fairly rapid decline in the value of the insulation
resistance measured. It will be noted that ~he composition
for which Graph A was plotted contained neither of the
special antioxidan~s~ but did contain a conventional
combination o~ antioxidants, namely, the Ageri-te ~ and
Santowhite Crystals, in t~e ratio of 1.5 for Agerite ~A
and 0.25 for the Santowhite Crystals, and that in Graph B
the value of the Agerite MA and Santowhite Crystals was
doubled from the values in Graph A. A significant increase
in the insulation resistance occured but there was also
a very rapid decline in the insulation resistance.
Considering next the Graph C, it is evident that 1.5
parts of ~gerite ~ were combined with 1.5 parts of the
ZMB-2~ or the zinc salt of a mercaptoimidazole. Here the
incxease in the insulati~n resistance was pronounced
for the first 20 weeks after which the curve essentially
levelled off at a value of about 2700 megaohms and after
that it declined gradually with further passage o~ time.
Considering next the Graph D, and the constituents
of the composition, it is evident that this composition
contained a combination of the æinc salt of a mercapto-
imidazole to the extent of 1.5 parts, and also contained
1.5 parts of the sterically hlndered di~tertiary butyl
phenol, sold commercially under the designation Irganox
1035. It is evident that this curve rose more xapidly
than in any of the others and to a much higher value than
any of the others, rising to a value of about 11,000
megaohms in a period of one year~ or about 52 weeks.
This is a unique and remarkable change in the insulation
resistance and in the stability of the insulation resis~
5C~3~
~lWC-2037
- 17 -
tance inasmuch as there is no decline in the insulating
resistance after a period of one year although there
was a very rapid increase in the insulation resistance
during approximately the entire year. Accordingly, it is
evident from this test tha~ a comparison of the graphed
results obtained for materials using the more conventional
antioxidants, and not using the combination of antioxidants
employed in the present invention, that the insulation resistance
an~ the insulation resistance stability are of a relatively
low order for compositions with such conventional antioxidants
although one would recognize tha-t the insulation resistance
values which were achieved for compositions of -tests A,B
and C were higher than the values achieved by flame resistant
compositions containing organic halogen flame retardants
previously known. Nevertheless, a very striking and unique
improvement in the insulation resistance and insulation
resistance sta~ility i.s found by the use of the combination
of the relatively small proportions of the two special
antioxidants i.n combination and, spec.ifically, the ZMB-2
and the Irganox 1035.
Considering next the tabulation of data for Graph
E in Table III, it is evident that the only difference
~om the tuhulat~on of data for Test D, Graph D is that
the Xrganox 1010 was used in place of the Irgano~ 1035
~nd it was a simple substitution in that the same quantity
of the Ir~anox 1010 was emp:Loyed as had been empl.oyed in
Test D, Graph D where Irganox 1035 was used. Please
not~ ~om the graph the totally remarkable plot of data
which was obtained from this experiment and that the
insulation resistance rose very rapidly and within a
per.iod of approximately 8 weeks, to a value of 12,500
megaohms and that it remained essentially constant for the
remainder~of the first full yearO
There is no e~planaticn by which the difference i.n
the insulation resistance property or in the s-tability
3~
41WC-2037
~ 18 -
of the insulation resistance property can be distinguished
from that found for the cornbination of Irganox 1035 and
ZMB-2 as sho~n in Graph D, but it is obvious from the
plot of data that Graph E is a most remarkable and
unique result to have been found for an insulation
resistance for the composition as set forth in Table III.
EXAMPLE 2
A comparison was also made between a wire prepared
w.ith a 30 mil wall having a composition corresponding
to test composi-tion A of Table III and a wire with a 20
mil wall prepared with a composition of the test compound
E of Table III. The data compiled in making this
eomparision is given in Table IV immediately below.
TABLE IV
_ _ _ _
30 mil20 mil
wall 7all
MECHANICAL lYOISTURE ABSORPTION
. _ . . ~
7 days at 70C, in mg/in2 1.51 0.93
EM-60 - UL and ICEA standard test.;
1 day: % Power Factor at 80v/mil0.36 0.38
Specific Inductive Capa-
citance (SIC~. 2.20 2.05
Stability Factor
7 days: % Power Factor at 80v/mil 0.280.30
SIC 2.20 2.06
14 days: % Power Factor at 80v/mil0.26 0.26
SIC 2.20 2.06
Stability Factor0.02 0.02
% SIC Increase:
1-14 days 0.00 0.49
7-14 days 0.00 0.00
FLAME RET~RDANCE
_
VW-l pass pass
UL-94 Vertical Flame pass pass
3~
41WC-2037
-- 19 --
TABLE IV (con't~
30 mil 20 mil
~all wall
Toluene Extraction; % 25.2 25.0
IEEE 383 and 323 Qualification* pass pass
Original Tensil, psi 1995 2071
Original Elongation, % 329 333
. .
*Heat aged -to simula-te 40-year thermal llfe, then received
220 megarads of gamma radia-tion prior to a 33-day
LOCA cycle and subsequently a Hipot to 2.4 kilovolts
per minute.
HEAT ~GING CHARACTERISTICS
at 158C a`ir oven
.
7 days: %RT** 87 92
-~RE~** 94 97
14 days: %RT 86 88
%RE 86 88
21 days: %RT 56 50
%~E 9 7
at 136 air oven (UI, requirement
for 125C rating)
30 Aays: % RT 100 89
% RE 92 90
60 Aays: % RT 93 84
%RE 88 84
4 hours at 70C - #2 AST~ oil
%RT 108 97
%RE gg 97
4 hours - air bomb
%RT 92 86
~RE 9~ 99
LOCA pass pass
~ ~3 5~3~
41WC~2037
- 20 -
**%RT is the percent of the oxiginal tensile retained
after heating for the indicated period.
***%~E is the percent of the original elongation retained
after the indicated heating.
From the content of Tahle IV, it is evident that
the orginal tensile of the 30 mil sample is approximately
the same as that of the 20 mil sample. In addition, the
elongation of the 30 mil sample is approximately equivalent
to that of the 20 mil sample.
Further, with regard to heat aging characteristics,
the heating at 158C in an air oven gave results which
are very comparable and demonstrate that the 20 mil wall
thickness of a wire product prepared with an insulation
coating of the composition E gives results which are the
equivalent of the 30 mil sample of composition A.
Further, with regard to the air oven heating at
136C, here again the results achieved show that the heat
aging characteristics for the 30 mil sample are a~out
e~uivalent to those of the 20 mil sample.
With ~urther regard to the 4-hour heating at 70C
in ~2 ~STM oil, the results obtained here again demonstrate
a substantial equivalency in performance of the 30 mil
sample as compared to the 20 mil sample.
With further regard to the 4-hour heating o:E the
samples in an air bomb, again a substantial equivalency
:is demonstrated between the two samples.
W;ith xegard to the mechanical moisture absorption Eor
1 days at 70C, the 30 mil sample absorbed more than 50%
more than the 20 mil sample.
~ series of tests known as the EM-60 tests were
performed on the two wire samples and as is evident in
Table IV, the results obtained are substantially the same
for the 3n mil sample and for the 20 mil sampleO
Concerning the percent of specific indictive capaci-
tance increase, the 20 mil sample showed a greater in-
3~
~lWC-2037
- 21 -
crease in the SIC measurement in the l to l~ day test,
but as a practical matter~ the difference ls not
significant in actual application of the wire products.
In the 7 to l~ da~vs period, there was no increase by
either the 30 or 20 mil sample.
Very significantly, both samples passed the UL-9~
vertical flame test. In addition, both samples passed
the VW-l test, the most difficult flame test procedure
used in the wire and cable field. The toluene extraction
percent for each of the two samples is essentially the
same. Both samples passed the IEEE 383 and 323 qualifi-
cation test. ~ll of the foregoing tests are standard
tests and descriptions thereof can be obtained from
standard references and from other patents which deal
with essentially the same subject matter as the subject
application.
The particular sample of wire which was used in each
of the tests was a #12/l9 tinned stranded conductor.
In other words, the wire had nineteen tinned strands.
Since numerous embodiments can be made of the
invention as described in the foregoing application, it
should be realized that the foregoing is given as
illustrative of the invention and i~ not to be inter-
preted as limiting except to the extent set forth
in the attached claims.
