CA1277653C

CA1277653C - Optical wave guide compounds

Info

Publication number: CA1277653C
Application number: CA000485284A
Authority: CA
Inventors: Sal Randisi
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-09-10
Filing date: 1985-06-26
Publication date: 1990-12-11
Anticipated expiration: 2007-12-11
Also published as: JPS6184614A; AU4696685A; BR8504329A; JPH0644090B2

Abstract

OPTICAL WAVE GUIDE COMPOUNDS
ABSTRACT OF THE DISCLOSURE
Compositions are provided which are water resistant;
soft at both ends of a wide temperature spectrum, i.e., -75°F to 650°F, compatible with the materials of which fiber optic units are formed, and are made from a mixture of a lubricating fluid, particularly a natural or synthetic hydrocarbon petroleum distillate, approximately 1% polybetene, a silicon dioxide thickener, and, optionally, polytetrafluoroethylene.
Other materials, such as coloring agents, can also be employed.

Description

~ 53 27319~10 OPTICAL WAVE GUIDE COMPOUNDS
FIELD OF T~E INVENTION
Increasingly in modern day technology, especially in the technology employing beams of light for the transmis-sion of data, or other communications, fiber optics are being employed. Since the fiber optic element, itself, is generally relatively fragile, in order to employ it, one or more such fiber optic elements are held together in a bundle and the bundle is inserted into a protective tube, such as a poly-ethylene jacket.
The fiber optic elements, however, cannot be merely allowed to remain loose in a jacket of the type referred to.
If such were to be the case, then almost any kind of mechanical shock or bending could result in damage to or breakage of the fiber optic element. In view of the substan-tial length of many of these presently used fiber optic data transmission cables, replacement or repair to the fiber optic elements would be both difficult and expensive.
Accordingly, means must be provided for cushioning o~ the fiber optic elements within the jacket in which such elements are carried from one point to another.
In providing lubrication for or cushioning of the fiber optic elernents which are carried in a jacket or sheath, care must be taken to assure that the optical qualities of the fiber optic elements are not diminished. Thus, in formulat-ing a lubricant or cushioning agent for use with fiber optic elements carried in a sheathr the formulation must provide, not only, the necessary lubrication or cushiGning, but must also not deleteriously affect the optical qualities of the element.

., 1 ,~

2731g-10 77~;5:~

" Compounds used with fiber optics should be also compatible with sea water immersion t fresh water immersion, and alkali immersion to pH13.
These compounds must also be free of air entrap-ment, and exhibit excellent adhesion - cohesion char-acteristics.
These compounds must remain soft at bo-th ends of the temperature spectrum, and afford e~tremely low attenuation.
These compounds must also be waterproof and be suitable for use as a moisture barrier. These compounds must also be good dielectrics."
composition of matter which will satisfy all of these various requirements, is thus the object of the present invention.
DESCRI.PTION OF THE INVENTION
-In accordance with the present invention, an optical wave guiae compound has been developed which satisfies the various requirements for such a material, including the pro-vision of sufficient lubricity or cushioning for a fiber optic element, or series of such elements, placed ~ithin a jacket, minimal or no interference with the optical properties of the optical fiber elements so contained, and a material which is both non-toxic and non-melting.
The composition of the material of the present invention, which will hereinafter be referred to as a Eiber optic lubricating composition, includes, as the major compon-ent, a lubricating fluid, such as a natural or synthetic petroleum distillate. Included in the composition is a thickening agent, particularly, a silicon dioxide po~der, such ~L~771Ei53 as a fumed silica. Further, the composition can contain a finely divided, polymeric fluorocarbon powder, such as poly-tetrafluoroethylene (for example, of the type sold under the trademark Teflon), and may contain various additives, such as coloring agents, etc.
While the materials just recited are important to the composition, and, to a great extent, are set forth in applicant's prior United States Patent, United States 4,396,514, issued August 2, 1983, and entitled "Lubricating Composition and Method of Making," the critical component of the composition of the present invention is polybutene, particularly, a polybutene oil of moderate to high viscosity and tackiness. The inclusion of this material having the formula:
CH3 / IH3 ~ CIH3 I t I t CH2-- c CH2 CH3 \ CH3J n wherein n is from about 15 to 35, provides the necessary lubricity and cushioning for use in connection with the fiber optic elements. The amount of the polybutene contained in the formulation should be approximately 1~, with a permissible variation of approximately 10%. While the value of n in the formulation set forth above has been given as from 15 to 35, the preferable value of n is from about 20 to 25.
It has been found that the method of forming the lubricant and cushioning composition of the present invention is preferably that set forth in the afore-referenced United States Patent 4,396,514.

, ~ 7319-10 "DESCRIPTION OF DRA~INGS
Figure l shows a typical construction of a cable employing fiber optics.
Figure 2 shows a schematic of an extrusion process".
DESCRI TION OF THE PREFERRED EMBODIMENT
In accordance with the present invention, a fiber optic lubricating composition for use with optical fiber elements contained in a jacket includes the following:
a. a hydrocarbon lubricating liquid;
b. a silicon dioxide in the form of a finely divided silica powder with particles ranging from about 7 to about 40 millimicrons in size, said silicon dioxide comprising from about 2 to 10% of said composition;
and c. an oily polybutene having the forrnula:
IH3 ~ IH3 ~ IH3 t H~ CM2 c CH2 CH3 C 3 n where n is from about 15 to about 35, preferably from about 20 to 25, said polybutene comprising approximately 1~, by weight of the total composition.
" Said fiber optic composition may also contain a finely divided, polymeric, fluorocarbon powder com-prising polytetrafluoroethylene in the form of ~r ~ S3 27319-lO

particles ranging from 0.1 to lOO microns in size and having a melting temperature above 450F, said polymeric fluorocarbon powder comprising from about O to about 3% of said composition."
Aspreviously indicated, the preerred method for forming the composition of the present invention is through use of a disc impeller at elevated temperatures as set forth in the afore-referenced United States Patent 4,396,514.
The lubricating fluid employed in this invention may comprise a natural petroleum distillate including various ~rades of grease and oil and/or may also comprise a synthet.ic petroleum distillate or synthesized hydrocarbon.
The synthesized hydrocarbons preferred for use in this inven-tion are low molecular wei~ht saturated polyalphaolefins and hydrogenated oligomers of short chain normal alphalolefins.
These synthetic hydrocarbon lubricating fluids are readily available commercial commodities. They are marketed by Uniroyal under the trade name "Uniroyal PAO" and by Gulf Petrochemicals under the tradename "Synfluid"; both fluids ~0 are available in different grades or weights. It is preferred for this invention that a blend of about 6 and ~0 weight oil be used. It i.s also contemplated that these synthetic hydro-carbons may be used in the practice of this invention either purely by themselves or intermixed with natural petroleum distillates.
The use of these synthetic fluids insures a highly pure lubricating fluid which additionally helps conserve shrinking world supplies of natural petroleum reserves.

~Z77~3 27319-10 Any polymeric fluorocarbon powder can be used in this invention provided it is characterized by a high melting point, i.e., above 450F, and consis~s of finely divided particles whose average size ranges from submicron (e.g. about 0.1 micron) to 100-micron size. Preferably, these particles will have an average particle size of about 0.7 micron. Preferred are the polymeric fluorocarbons selected from the group consisting of polytetrafluoroethylene (TFE) and fluorinated ethylene propylene (FEP) copolymer. The polymeric fluorocarbon compounds operable in this invention may be purchased as readily available commercial commodities under such trade names as"TFE Teflon"
and "FEP Teflon." The polytetrafluoroethylene is a polymer of a fully fluorinated hydrocarbon of the basic chemical formula (~CF2 - CF2-) containing 71 percent by weight of fluorinated ethylene. The propylene copolymer is a fully fluorinated resin prepared by polymerization of tetrafluoroethylene and hexa~
fluoropropylene to form a copolymer containing about 5 to about 50 weight percent hexafluoropropylene and about 95 to about 50 weight percent tetrafluoroethylene. These copolymers have respective melting points ranging from about 480F to about 560F. Especially preferred for use in this invention is poly-tetrafluoroethylene ~PTFE).
It is preferable that the polymeric fluorocarbon comprises up to about 3% of the lubricating composition. It is also contemplated that higher percentages can be used in the practice of the invention.
The silicon dioxide or fumed silica of the disclosed invention is produced from silicon tetrachloride in a flame hydrolysis process with oxygen-hydrogen gas. This process produces highly dispersed silicon dioxide of amorphous structure and great purity with controlled particle size. The finely ,~

~2~5;`3 divided fumed silica powder has particles which may range from about 7 to 40 millimicrons in size. It has also surprisingly been found that silicon dioxide particulates of such small size do not have abrasive characteristics. The preferred size particle for this invention ranges from 12-16 millimicrons.
Particles of various sizes may be intermixed in the lubricating composition or may all be of approximately the same size. The fumed silica powder is a readily available commerical product of the Degussa Corporation and is marketed under the trade name "Aerosil."
The extreme thixotropic filler action of the f~ed silica powder is a function of the silanol groups present on the surface of the particles in optimal density and their propensity to form hydrogen bonds. This characteristic may, in large part, account ~or the great stability of the dispersion comprising the lubricating composition and thereby prevent the settling out or separating of the polymeric fluorocarbon powder from the lubricating fluid. Furthermore, the electrical conductivity of the fumed silica is very poor and qualifies it in effect as an insulator. Even under adverse conditions (i.e., an exceptionally high moisture content), the electrical resistivity of the fumed silica is still about 10 X 1012 Ohm X cm at packed densities of 50-60 g/l. This property greatly contributes to the high eleetrical resistanee of the lubricating eomposition of whieh it is an integral part. It is preferred that the silieon dioxide or fumed siliea particles eomprise from about 2~ to about 10% of the lubricating composition.

f,'~' ~,~

.

¦ The polybutene employed ~n ~ccordance with the ~ I present invention, in amounts of about 1% based upon th~ to~al : ¦ weight, is an inert oil of moderate to high v~6co~ity and tackiness. The amount of polybute~e which can be incorporated can vary within ~ lOX of the preferred amount. The polybutene has the formula:
. ,, : l 3 / IH3 ~ CH3 ~o ~ c I-~u2--L~C!!2_c cu2 `~ ~ . . .
~............... , . . .
where n is from 15 to 35, preferably from nbout 20 to 25.
, , The average ~olecular weight of the mater~al i~ thus between about l,000 and 2jO00, preferably in the range of about ~,500.
. A preferred ma~erlal for use in connection.with the present inven~ion i9 the materlal sold by Chevron Chemical Company under the designation polyb~tene grade 32.
: The propertie~ of thi~ polybutene are a8 ollows:
Properties TestM~ Value Physical n Vl ~ 1 *
~lor, ~ dner ASDM D l544 Specific Gr ~ ~ ~t 15/15C ASTM D 287 0.905 P ~ ~/Gallon a~ . I

N~ber Average mol. wt. ;
Me~olab O~ter ~l180-6 1.400 . . , . ''';. ' ' '' ~2~6~3.i :

Properties Test ~ethod .Value Mblecular W~ Dlspersion Index SM 1~0-6 ~8 Viscosity 40-C SUS ~SDM D 445 108.500 Viscoslty 40-C cSl ~nd D 446 23.400 Viscoslty 100-C SUS ASIM D.445 2.820 Viscosity lOO~C cSl and D ;b6 604 Viscosity Index . ~I D 567 118 . . Flash Point C ASTM D 92 224 ....
Fire Point C A5~nM D 92 271 Pour Point C ~STM D 97 b Loss on Heatin~ O
(Five Hr. 1~0~) ASDM D.6 0.4 Cbefficient of Thermal . Expansion per C
. (15C-100C) S~ 15-23 0.00066 CheI~cal BrcnL~le No. g/lOOg 5M 20-28 13 Neut Value, ~g K~HIg ASIM ~ 664 ~.01 Organic Chloride as Chlor.~ne, Wt~ SM 205-12 Ø003 Inorganic Chlorides and Sulfates ~ D 878 . Nbne ~, ... ......
Total ,Sulfur, X A~nM D 1S52 0.01 Carb~n Residue, % ASTM D 189 Nbne .: Water Ccntent, ppn . ASTM D 1533 40 . . ....
. I . ' ' ,' ,.
., . * Clear, brlght and free ~rom ~edimen of suspended ~tter.
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7~ 53 -The compositions formed in accordance wlth the present invention are thixotropic and are operable over ~n extremely wide temperature ran~e, i.e., from about -75~F to ~650F. They are water resistant, remain soft at both ends of the temperature spectrum, and afford zero attenuation. Some of the compounds are compatible with sea water i~mer~ion, fresh water immerslon, alkall i~mersion to pH 13, and to mlld ~cid immer~ion for short durations. They are compatlble with a variety of jacket materials, including polypropylene, polyethylene, and poly-0 Icarbonate materials. ~," Fig. 1 illustrates a fiber optlc structure. In the center of the structure a tencion member or support rod is placed, constructed of a strong material such as steel rod. Surrounding this member ¦ are optical fiber elements 2 constructed of fiber '¦ optic material. A buffer layer of the-composition of ¦I this invention is placed between the fiber optic and , ¦ the tension member to properly buffer and support the fiber optics. These are placed in a protective tube 6 which is placed within a stronger protective tube S
with the composition 3 of this invention placed be~ween them. The materials of this invention axe also placed around the individual fibers 2 and protective casing 6 to support the fiber and also to prevent attenuation of the light beam. The composition 3 placed between the fiber optic and the first protective tuber and placed between a plurality of first protective tubes and a second prvtective tube may be the same or different dependlng on the requirements of support and also depending on the dielectric qualities needed. An example would be where the composition 3 between the fibex opti~ and first protective tube is a compositlon for use wlth fiber optic elemen~s comprising a stable di~per~ion of:

~2 ~ 3 . . a. a hydrocarbon lubricating liquid;
b. a silicon dioxide in the form of a finely divided ,l . ~ilica powder with partioles ranging from about 7 to about 40 millimicrons in size, said silicon dioscide ¦ comprising from about 2 to }0% of said composition;
. c. an oily polybutene having the ~ormula:
.: . ' ,.

. CH3 ~ CH3 ~ CH3 CH3 ----- C~ ;2 -- j iCH~ -- C = CH2 . CH3 ~3 .
where n is form about 15 to about 35, said polyhu~ene comprising approxlmately 1%, by w2ight, of said composition, and the ~omposition 3 between the plurality of first protective tubes and a second protective tube is a composlti-on for use with fiber optic elements comprising,a stable dispersion . of: .
. a. a hydrocarbon lubricat~ng l~quid;
:¦ b. a silicon dioxlde in the form of a inely divided silica powder with particles ranging from about 7 to about 40 millimicrons in size, said silicon dioxide . . comprising from about 2 to 10~ of said composition;
c. an oily polybutene having the formula:
,1 IH3 ! l3~ T3 ~H3 -f ~ CH~-- C--;T C~2--C ~ CH2 ~H3 \ C~3/
n .
11 , ' ' . .
, where n ls from abou~ 15 to about 3S, ~aid polybutene com~risina a~Droximatelv 1~ bv welaht. o~ 9ai~

composition, including a finely divl~de~ plymeric, flurocarbon poweder comprising polytetrafuoroethylene in the form of particles ranging from O.l to lOO microns in size and having a melting temperature above 450 F, said polymeric flurocarbon powder comprising from about O to about 3~ of said composition.
It will be understood that the composition may be used with the fiber optic structure shown in Fig. l or any other flber optic or similar structure.
Fig. 2 illustrates schematic of the extrusion process and shows the structure forming.
As shown~ in FigO l and 2, Figure l illustrating the fiber optic unit and Figure 2 illustrating the extrusion process. As shown in Figs. l and 2, to employ the compositions of the present invention, they are generally introduced-into the extrusion die head lO of an extruder 9 which also carries the'optical fiber elements as shown in Fig. l and the molten polymer which is used to form the jacket 5. By employment in this way, the composition encases the optical fiber elements and flood inner portion of the jacket that is the area 3 with dielectric n!at.erial o~ this inver.tion. The ~cmposition thus redvces t~.e movement of the o~tical flber elements ~.~ithin 1;h~
~acket , so as to control any attentuatlon'that may arise due to rnovement, permitting control of attentuation to less than ~ dB/km, an industry requirement. It also creates a moisture barrier and discourages moisture accumulation within the jacket.
If moisture accumulation is not prevented, the moisture may'attack the acrylate claddîng which is generally formed on the optical fiber'elements, causing signal distortion and attentuation. Thus~ the waterproofing properties of the composition of the present invention are essential to the integrity of the overall optical fibe'r construction and to signal stability.

~ 53 , ' .' . .. .~.

. Particùlarly ~hen more than one cptlcal f~ber : element is included ln the overall c~ble construetion, the compositlons of the present invention act as lubricants. Thu~, the compositions ~ushion and reduce the amplltude of movement within the ~acket of the multi-fllamPnt construction.
The composl~ions of the present invention mee~ the specificat~ons listed below: -~ Value Speciflcation~:
Operatin~ temperature (-60C ~o 345C) -75F to 650F
Viscosity - (Penetrometer) Fro~ 275~ 10 to 33G~ 10 Dropp m g Point (F ~U~ ~-566 in Heat Ch~mb~r) N~ ~elt : Color ~hite Tr~nslucent to Ollve Green Texture 9mooth - ~uttery Odor - Nbne pH (Base Fluid) 7.5 i RLst test ~Inhibited - xust ~nd corrosion) ASIM D-1743 ~a88 ,. , Cxidaticn ~Inhibited~(AS~DM D~942) 0 ~ter Resistance ~ASDM D~1264) lOOX water res~stant Effect on copper tASDMD-1261) O
Effect on Fiber c~t ~ 8 (Con~g Test~ O
Oil ~paration S~M D-1742 &
FIM-781-B) Le~s ~n 1110 of 1%
: D. C. Resist~vi~ a~ 25C ~hm-cm 1700 x 1 2S ~ ation Resis~ce (o~m~on 1 . ........ at 100 volts) 1-2 x 10 .,',.. . ' ' ."' ''`.

.. . w 13 - j, .
. , .~

~27~6~;3 , 27319-10 Property (Test Method) Value Dielectric constant at lmHz 2.10 Compound life (encapsulated) undetermined - over 10 years Evaporation Loss, wgt% (22 hrs.
at 149C) (300F) Less than 0.3%
Gamma radiation 2X108 RAD
Dissipation Factor at ambient F .00064 Density/gallon 8.725 Dielectric dissipation factor of P.T.F.E. at 106 2.0-2.1 Polyethylene stress cracking test MS-17000 sec. 1078 Pass Air entrapment None Pumpability 100%
Dry Heat Aging 0 Slump 0 Non Toxic The com~positions set forth below are illustrative of the various embodiments of lubricating compositions falling within the present invention:
Example 1 Polyalphaolefin Oil 69.00%
Mineral Oil U.S.P. 17.00%
PTFE 3-00%
Fumed Silica 9.00%
Polyethylene Glycol 1.00%
Polybutene Grade 32 1.00%
100. 00%
Example 2 Polyalphaolefin Oil 72.00%
Mineral Oil U.S.P. 17.00%
Fumed Silica 9,00%
Polyethylene Glycol 1.00%
Polybutene Grade 32 1~00%
100 . 00%
Color Polychrome Orange (Trace to Sample) ,~

~12~3 :`
-.-. l . .......

' 1-- . . . .,.., i It ls alsQ wlthln the contempLation of this ~nvention ¦ to lnclude smal~ amounts of other compos~tions ~o a~ to ¦ complement or further increase the iubricat~ng compositlvns ¦ desirable characteristics as was detailed in ~he examples.
¦ Contempla~ed compositions include dye~, antioxidan~s, cationic ... ¦surfactants, rust inhibi~ors, emulsifier6, a~tapulgite ~elling :~ : ¦agents, and ~mida~oline oleate.
. ¦ As indlca~ed, the composi~ions of ~he present ¦ in~ention are partieularly useul in con3unc~ion with flber ¦ optic constructlons.. Xspecially, these compositlons are useful . ¦ for ~he lubr~cation and cushioning of fiber 9p~iC elements .... ..
heId wlthin a polymeric ~cke~.
While specific embodiments of he in~en~ion have been shown and de8crlbed, ~he lnven~lon shou~d not be considered as limited except as ~ndlcated in the appended . .. cla~ms.
., ',' ,. . ' , ', . , ., . ' ' ,' ''', .. ' , ,..','. , , " ', ""'' "','' ,', '', .' . , ', ,.
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.' . . .,; ,,, '-' ~',,., -', ''', . ' . ' ,''"`'.1',, , 1 . . ' ' ' ,,.,,'~' '' ` '`, . ~ . ' ~ , ~ . . ' . !

Claims

CLAIM 1 ( amended ):
1. A composition for use with fiber optic elements comprising a stable dispersion of:
a. a hydrocarbon lubricating liquid;
b. a silicon dioxide in the form. of a finely divided silica powder with particles ranging from about 7 to about 40 millimicrons in size, said silicon dioxide comprising from about. 2 to 10% of said composition;
2. an oily polybutene having the formula:
where n is from about 15 to about 35, said polybutene comprising approximately 1X, by weight, of said composition.

2. The composition of Claim 1, wherein the lubricating liquid is a petroleum distillate.
3. The composition of Claim 1, wherein the lubricating liquid is synthesized hydrocarbon.
4. The composition of Claim 1, wherein the lubricating liquid comprises a petroleum distillate and a synthesized hydrocarbon.
5. The composition of Claim 1, wherein n is from about 20 to 25.
6. The composition of Claim 1 including a finely divided, polymeric, fluorocarbon powder comprising polytetrafluoroethylene in the form of particles ranging from 0.1 to 100 microns in size and having a melting temperature above 450°F, said polymeric fluorocarbon powder comprising from about 0 to about 3% of said composition.
7. The composition of Claim 6, wherein the lubricating liquid is a petroleum distillate.
8. The composition of Claim 6, wherein the lubricating liquid is synthesized hydrocarbon.
9. The composition of Claim 6, wherein the lubricating liquid comprises a petroleum distillate and a synthesized hydrocarbon.
10. The composition of Claim 6, wherein n is from about 20 to 25.
11. A fiber optic unit comprising:
(a) a plurality of fiber optics, (b) a plurality of first protective tubes, whereby each of said tubes surrounds each fiber optic, (c) a composition between the fiber optic and the first protective tube, and between the plurality of first protective tubes and a second protective tube for supporting the fiber optic and substantially maintaining the optical characteristics of the fiber optic, said composition being dielectric and as defined in Claim 1.
12. The fiber optic unit of Claim 11, wherein the hydrocarbon lubricating liquid is a petroleum distillate.
13. The fiber optic unit of Claim 12, wherein the hydrocarbon lubricating liquid is synthesized hydrocarbon.
14. The fiber optic unit of Claim 12, wherein the hydrocarbon lubricating liquid comprises a petroleum distillate and a synthesized hydrocarbon.
15. The fiber optic unit of Claim 12, 13 or 14, wherein is from 20 to 25.
16. A method of fabricating a fiber optic unit and including:
(a) providing an extrusion die, (b) providing a plurality of optical fibers to said die, (c) providing to said die materials to form a plurality of first protective tubes and a second protective tube, (d) providing a dielectric composition as defined in Claim 1 to said die, for use in said fiber optic unit to substantially maintain its optical characteristics, and (e) extruding a fiber optic unit from said die with said composition between the first protective tube and the fiber optic, and between the plurality of first protective tubes and a second protective tube.
17. A method of Claim 16, wherein the composition between the first protective tubes and the second protective tube is the composition of Claim 6 and the composition between the fiber optic and the first protective tube is other than the compound of Claim 6.
18. A method of Claim 16, wherein the composition between the fiber optic and the first protective tube is the compound of Claim 6, and the composition between the first protective tubes and the second protective tube is other than the composition of Claim 6.
19. A method of Claim 16, where composition between the fiber optic and the first protective tube is the compound of Claim 6, and the composition between the first protective tubes and the second protective tube is the composition of Claim 6.
20. The method of Claim 16, 17 or 18, wherein the hydrocarbon lubricating liquid is a petroleum distillate.
21. The method of Claim 16, 17, or 18, wherein the hydrocarbon lubricating liquid is synthesized hydrocarbon.
22. The method of Claim 16, 17 or 18, wherein the hydrocarbon lubricating liquid comprises a petroleum distillate and a synthesized hydrocarbon.
23. The method of Claim 16, 17 or 18, wherein n is from 20 to 25.
24. A fiber optic unit comprising:
(a) a plurality of fiber optics, (b) a plurality of first protective tubes, whereby each of said tubes surrounds each fiber optic;
(c) a composition between the fiber optic and the first protective tube supporting the fiber optic and substantially maintaining the optical characteristics of the fiber optic, said composition being dielectric and as defined in Claim 1, and (d) a second protective tube surrounding said plurality of first protective tubes.
25. A fiber optic unit comprising:
(a) a plurality of fiber optics, (b) a plurality of first protective tubes, whereby each of said tubes surround each fiber optic, (c) a second protective tube surrounding said plurality of first protective tubes, (d) a composition between the said plurality of first protective tubes and said second protective tube substantially maintaining the optical characteristics of the fiber optic, said composition being dielectric.
26. A fiber optic unit of Claim 24 wherein said composition is the composition of Claim 6.
27. A fiber optic unit of Claim 25 wherein said composition is the composition of Claim 6.
28. A fiber optic unit of Claim 11, wherein the composition between the plurality of the first protective tubes and the second protective tube is the composition of Claim 6 and the composition between the fiber optic and the first protective tube is other than the compound of Claim 6.
29. A fiber optic unit of Claim 11, wherein the composition between the fiber optic and the first protective tube is the compound of Claim 6, and the composition between the plurality of the first protective tubes and the second protective tube is other than the composition of Claim 6.
30. A fiber optic unit of Claim 11, where composition between the fiber optic and the first protective tube is the compound of Claim 6, and the composition between the plurality the first protective tubes and the second protective tube is the composition of Claim 6.
31. A method of fabricating a fiber optic unit and including:
(a) providing an extrusion die, (b) providing a plurality of optical fibres to said die, (c) providing materials to said die to form a plurality of first protective tubes and a second protective tube, (d) providing to said die a dielectric composition for use in said fiber optic unit to substantially maintain its optical characteristics, said dielectric composition being as defined in Claim 1, and (e) extruding a fiber optic unit from said die with said composition between the first protective tube and the fiber optic.
32. A method of fabricating a fiber optic unit and including:
(a) providing an extrusion die, (b) providing a plurality of optical fibers to said die, (c) providing to said die materials to form a plurality of first protective tubes and a second protective tube, (d) providing to said die a dielectrical composition for use in said fiber optic unit to substantially maintain its optical characteristics, said dielectric composition being as defined in Claim 1, and (e) extruding a fiber optic unit from said die with said composition between the plurality of first protective tubes and the second protective tube.
33. A method of Claim 31 wherein said composition is the composition of Claim 6.
34. A method of Claim 32 wherein said composition is the composition of Claim 6.