CA2132992C - Strippable coating for optical fiber - Google Patents
Strippable coating for optical fiberInfo
- Publication number
- CA2132992C CA2132992C CA002132992A CA2132992A CA2132992C CA 2132992 C CA2132992 C CA 2132992C CA 002132992 A CA002132992 A CA 002132992A CA 2132992 A CA2132992 A CA 2132992A CA 2132992 C CA2132992 C CA 2132992C
- Authority
- CA
- Canada
- Prior art keywords
- optical fiber
- oligomer
- weight
- coating material
- coated optical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/4403—Optical cables with ribbon structure
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
- C03C25/10—Coating
- C03C25/104—Coating to obtain optical fibres
- C03C25/106—Single coatings
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
- C03C25/10—Coating
- C03C25/104—Coating to obtain optical fibres
- C03C25/1065—Multiple coatings
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/245—Removing protective coverings of light guides before coupling
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/4429—Means specially adapted for strengthening or protecting the cables
- G02B6/443—Protective covering
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2913—Rod, strand, filament or fiber
- Y10T428/2933—Coated or with bond, impregnation or core
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2913—Rod, strand, filament or fiber
- Y10T428/2933—Coated or with bond, impregnation or core
- Y10T428/2964—Artificial fiber or filament
Abstract
A coating system for individual glass fibers 12 of a lightwave communications system has improved strippability, particularly in situations where a group of such fibers are arrayed together in what is known as a ribbon 20. A preferred embodiment includes two layers (primary 14 and secondary 15) of polymeric materials surrounding the glass fiber 12. The primary layer 14 comprises an oligomer (50-80% by weight), a diluent (15-40% by weight), and additives (5-35% by weight).
The oligomer comprises polyol "A," diisocyanate "B," and a hydroxy-terminated alkyl acrylate "C" having the structure C-BA-B-C. At least one of the additives contains a non-crosslinked hydrocarbon component (1-20% by weight) having a structure R1 - (R)n - R2; where R1, R2 comprises an alkyl group or an OH group, and R is acombination of C, H or C, H, O. In an alternative embodiment, the need for a diluent is substantially eliminated by using an oligomer having the structure E-D-E where "D"
represents a carboxy-terminated polyol, and "E" represents a glycidyl acrylate.
The oligomer comprises polyol "A," diisocyanate "B," and a hydroxy-terminated alkyl acrylate "C" having the structure C-BA-B-C. At least one of the additives contains a non-crosslinked hydrocarbon component (1-20% by weight) having a structure R1 - (R)n - R2; where R1, R2 comprises an alkyl group or an OH group, and R is acombination of C, H or C, H, O. In an alternative embodiment, the need for a diluent is substantially eliminated by using an oligomer having the structure E-D-E where "D"
represents a carboxy-terminated polyol, and "E" represents a glycidyl acrylate.
Description
STRIPPABLE COATING FOR OPTICAL FIBER
Technical Field This invention relates generally to a protective coating for an optical fiber, and more particularly to a coating which can be easily removed from the optical fiber.
Back~r~nd of the Invention In the manufacture of optical fiber, a glass preform rod is suspended vertically and moved into a furnace at a controlled rate. The plero~ softens in the furnace and a glass fiber (also referred to as an optical fiber) is drawn freely from the molten end of the preform rod by a capstan located at the base of a draw tower.
o Because the surface of the glass fiber is susceptible to damage caused by abrasion, it is necessary to coat the fiber after it is drawn but before it comes into contact with any surface. Inasmuch as the application of a coating material must not damage the glass surface, the coating material is applied in a liquid state. Once applied, the coating material must solidify before the glass fiber reaches the capstan. This is typically accomplished within a brief time interval by photocuring -- a process in which the liquid coating material is converted to a solid by exposure to electromagnetic radiation.
Because the fibers are thin and flexible, they are readily bent when subjected to mechanical stresses such as those encountered during h~nt11ing or exposure to varying temperature environments. Such bends in the fiber frequentlyresult in loss that is much greater than the intrinsic loss of the fiber itself, and it has been found desirable to protect the glass fiber against such bending. Accordingly, the coating material is required to cushion the glass fiber against bends and two layers of coating materials are typically applied to the drawn optical fiber. An inner (primary) coating, having a relatively low modulus, is applied directly to the glass fiber; and an outer (secondary) coating, having a relatively high modulus, surrounds the primary coating. Together, these coatings desirably protect the inherently high tensile strength of the glass fiber so long as the primar.,v coating material remains bonded to the glass.
However, in what appears to be a contradictory requirement, it is also desirable to be able to easily strip the coating(s) from the glass fiber -- particularly when a number of fibers are bonded together in an array such as shown in U. S. Patent 4,900,126 which leads to yet another performance attribute that coating materials need to possess.
Indeed, if the coating materials cannot be cleanly and easily stripped, then splicing and connectorizing operations will be seriously hampered.
U. S. patent 4,472,021 discloses a strippable coating for an optical fiber which comprises from about 2% to about 20% of an organic polysiloxane additive having a plurality of hydroxy-termin~tçd groups which are joined to some of the silicon atoms in the polysiloxane chain by a carbon-to-silicon bond. This particular additive, however, exhibits low adhesion to the glass fiber which adversely affects the handling propcillies of the coated optical fiber during the manufacturing process. Low adhesion is a problem which, in the worst case, leads to "del~min~tion"
and the ensuing incursion of water, particularly upon exposure to high humidity,which attacks the glass surface and reduces tensile strength.
What is needed, and seemingly what is not disclosed in the prior art, is an additive for use in a coating for optical fibers which improves st~ippability while still m~int~ining a&esion to the glass fiber.
Summa~ of the Invention An optical fiber comprises a glass portion for guiding lightwaves which is covered by one or more layers of a coating material to protect the glass from abrasion. The coating material is improved by adding 1-20% by weight of a non-crosslinked hydrocarbon component to a formulation comprising: an oligomer (50-80% by weight); a diluent (less than 50% by weight); and other additives (5-35% by weight). The improved coating material is easily removed from the glass portion while m~ g good adhesion thereto during normal use and h~n~11in~.
In a plefelled embodiment of the invention, the oligomer has an overall structure C-B-A-B-C in which "A" represents a polyol, "B" represents diisocyanate, and "C" represents hydroxy-termin~ted alkyl acrylate. The hydrocarbon component has the structure Rl - (R)n - R2; where Rl, R2 comprises an aL~yl group or an OH group, and R is a combination of C, H or C, H, O.
In an alternate embodiment of the invention, the need for a diluent is substantially elimin~ted by using an oligomer having the structure E-D-E where "D"
represents a carboxy-tennin~te~l polyol, and "E" represents a glycidyl acrylate.Brief Description of the D. ~. in~
The invention and its mode of operation will be more clearly understood from the following detailed description when read with the appended drawing in which:
FIG. 1 is an end view, in cross section, of an optical fiber which includes a coating system;
FIG. 2 is a perspective view of an optical fiber ribbon showing a group of coated glass fibers bonded together with a matrix material;
FIG. 3A-3C illustrate the use of a ribbon-stripping tool showing three progressive stages in the removal of matlix and coating materials from a group of glass fibers;
FIG. 4A-4C illustrate various outcomes of the ribbon-stripping 3 213~992 -procedure; and FIG. 5 is a graph which illustrates the effect of aging on pullout force for dual-coated fiber.
Detailed Description FIG. 1 shows an end view, in cross section, of a coated optical fiber 10 comprising a glass fiber 12 surrounded by a protective coating system comprisinglayers 14, 15. It is well known to draw glassy optical fiber from a specially prepared, cylindrical preform which has been locally and symmetrically heated to a temperature of about 2000~C. As the preform is fed into and through a furnace, glass fiber 12 is 0 drawn from the molten material. A protective coating system is applied to the glass fiber 12 after it has been drawn from the preform which preferably comprises twolayers of radiation-cured polymeric m~teri~l~. An inner layer 14 contacts the glass fiber 12 at a glass-coating interface 13 and is referred to as a primary coating material.
An outer layer 15, which is referred to as a secondary coating material, surrounds the inner layer. One method of applying dual layers of coating materials to a movingglass fiber is disclosed in U.S. Patent 4,474,830 which issued on Oct. 2, 1984 to C. R.
Taylor. Another method for applying dual layers of coating materials onto glass fiber is disclosed in U.S. Patent 4,851,165 which issued on July 25, 1989 to J. A. Rennell and C. R. Taylor. By way of illustration, the typical diameter of glass fiber 12 is about 125 micrometers, while the diameter of its core 11 is generally less than 10 micrometers for single mode fibers. (Core 11 is the region where light is substantially confined during its propagation along the glass fiber's longitudinal axis by therefractive index profile of the glass fiber.) And finally, each layer of coating material has a thickness of about 30 micrometers so that the overall diameter of coated fiber 10 is approximately 250 rnicrometers.
Referring now to FIG. 2, there is shown a perspective view of an optical fiber ribbon 20 showing a group of coated glass fibers 10-10 that are held together with an ultraviolet (UV)-curable matrix bonding material 21. The group of optical fibers are disposed in a coplanar parallel array, and while only four (4) fibers are shown, such arrays typically comprise twelve (12) individual fibers. The modulus of the matrix material has a value less than that of the outer coating layer of the fiber but greater than the modulus of the inner coating layer. The matrix material 21 fills the interstices, bonds together the optical fibers, and extends to the outside boundary of the ribbon. A typical UV-curable matrix material 21 is a mixture comprising aresin, a diluent and a photoinitiator. The resin may include a diethylenic-termin~ted resin svnthesized from a reaction of a hydroxy-termin~te~l alkyl acrylate with the reaction product of a polyester of polyether polyol of molecular weight of 1000 to 6000 Dalton with an aliphatic or aromatic diisoctyanate, or a diethylenic-termin~ted -4-- ~32992 resin synthesized from the reaction of glycidyl acrylate with a carboxylic-tennin~ted polymer or polyether of molecular weight 1000 to 6000 Dalton. The diluent may comprise monofunctional or multifunctional acrylic acid esters having a molecular weight of 100 to 1000 Dalton or N-vinylpyrrolidinone. For the photoinitiator, the s composition may include ketonic compounds such as diethoxyacetophenone, acetophenone, benzophenone, benzoin, anthraquinone, and benzil dimethyl ketal. In a typical composition, the bonding matrix may include a resin (50-90%), diluents (5-40%), and a photoinitiator (1-10%). All percentages are by weight unless otherwise noted. Other bonding matrices may include a methacrylate, a UV-curing epoxide oran unsaturated polyester. More detailed information regarding bonded arrays of optical fibers is available in the aforementioned U.S. Patent 4,900,126.
Bonded arrays of optical fibers, as discussed above, are commercially available from AT&T under the tr~dçm~rk of AccuRibbon~) lightguide cable, and isespecially useful for high fiber count installations in the loop and metropolitan area networks where splicing and in~t~ tion productivity are paramount. Each ribbon comprises 12 color-coded fibers for easy identification, and as many as 12 ribbons are stacked together for high density. The ribbon stack is surrounded by a core tubewhich may also contain a filler that prevents the incursion of water in outside plant applications.
Ribbon Slri~irlg Reference is made to FIG. 3A-3C which illustrate the use of a ribbon-stripping tool such as used by splicing technicians for mass fusion splicing. FIG. 3A
shows the principal elements of the ribbon stripping tool and associated appalalus.
Ribbon 20 is placed within fiber holder 30 to facilitate h~nclling of the fiber during the 2s stripping process. The stripping tool comprises holder grip 40 and main body 50 which are used for removing the various layers that surround a bonded fiber array.
Lid 53 is closed during the stripping operation and includes an inner surface 54 which cooperates with a heated platen 51 to frictionally hold the outside jacket material surrounding the glass fibers within ribbon 20.
Referring first to F~G. 3A, fiber holder 30 is shown in its closed position around ribbon 20 which about to be inserted into the ribbon-stripping tool.
The portion of ribbon 20 which is to have its coating layers removed extends beyond the forward end of the fiber holder so that it can be captured between platen 51 and the inside surface 54 of lid 53 when the lid is closed onto the main body 50. Upon 3s closure, opposing blades 55, 56 are positioned to cut partially into opposite sides ribbon 20 so that a well-defined break in the coating material can be made. The particular tool used is electrically heated from an AC power source which is converted to 12 volts DC for use by a heater element within the main body 50. Holder grip 40 is ~ 5 - 21 3~92 adapted to capture fiber holder 30 therein when its lid 43 is closed.
FIG. 3B illustrates the movement of holder grip 40 away from the main body 50 of the ribbon-stripping tool. Guide rails 45-45 allow the holder grip to slide into engagement with the main body in a controlled manner. A heater (not shown) within the main body raises the temperature of platen 51 to a predetermined level which weakens/breaks the adhesive bond at the interface 13 between primary coating 14 and glass fiber 12 (see FIG. 1 or 2) of the various coated fibers. Illustratively, a temperature of 100~C for about 2 minutes provides acceptable results. Once the bond is weakened/broken the rest of the operation involves sliding the primary coating lo along the glass fiber surface. The ability of the primary coating to slide will depend on it sliding friction with the glass fiber. This action will determine how easily the composite (matrix 21 and coatings 14, 15) can be removed and the amount of residue that remains on the bare glass fibers. Therefore, a non-crosslinking and non-reactive additive is incorporated into the primary coating formulation which remains mobile (i.e., free to diffuse) in the primary coating after cure so that when the stripping operation is pclrolllled the additive will be present at the surface of glass fiber 12 to thereby reduce sliding friction.
Finally, FIG. 3C shows end results of the ribbon stripping process in which glass fibers 12-12 protrude from ribbon 20 which is still held within the fiber holder 30. And matrix material 21 which has just been stripped away remains on the heated platen 51 of the main body 50. Having stripped the matrix and coating materials away from the glass fibers 12-12, FIG. 4A-4C are used for illustrating the various possible results of the stripping process and for discussing their acceptability.
For example, FIG. 4A shows an ideal condition wherein the matrix 21 and coating materials 14, 15 are fully removed from the glass fibers 12-12. Such results arefrequently possible with the present invention although the presence of some residues 16-16, as shown in FIG. 4B, is also acceptable provided they can be removed by gentle wiping with an alcohol-moistened cotton swab. However, FIG. 4C illustrates an unacceptable condition in which the coating materials have clung to the glass fibers so tenaciously that either breakage occurs or large patches remain that cannot be easily removed.
Coating Materials Coating materials not only protect the glass fiber from abrasion and cushion it against microbending loss, but they also help preserve its tensile strength.
However, in order to preserve tensile strength, the coating materials must stay bonded to the glass -- at least until they are stripped off, and then it is desirable that they be fully removable without leaving a residue on the glass. More specifically, the -6- 2132~92 interface between the primary coating material and the glass fiber must be characterized by suitable strength to prevent del~min~tion, and must be such that the coating system can be stripped from the optical fiber without tenacious residues being left on the fiber surface. On the other hand, the surface of the secondary coating 5 material must be such that tacking does not occur between adjacent convolutions of the fiber, resulting in a jerky payoff from a process spool.
Typical coating materials comprise urethane acrylate liquids whose molecules become crosslinked when exposed to ultraviolet light. Various additives are also present that enhance one or more properties of the coating. For example, lo photoinitiators are added to accelerate the curing process which is important because coated optical fiber is wrapped around spools for storage as soon as it is cured, and manufacturing speed is critical to profitability.
Curing is the conversion of the liquid coating material to a solid. In the present system this process is known as free radical cure wherein, upon absorption of 1S light, the photoinitiator components cleave to form free radical pairs which diffuse away from each other and react with acrylate-terrnin~tecl components to initiate a chain polymerization process. In addition to photoinitiators, coating materials further include diluents, antioxidants, adhesion promoters and, in some cases, additives to improve strippability. However, before addressing strippability, it is important to first 20 discuss the composition of the primary coating material which makes contact with the glass surface, and whose properties are the subject of the present invention.
In the prer~-led embodiment of the invention, primary coating 14 comprises a 30 micron-thick layer of a material that surrounds glass fiber 12. It has a low modulus (e.g., 106 Pa) to cushion the glass fiber against sharp bends that cause 25 loss to a lightwave signal. The primary coating illustratively comprises an oligomer (50-80%), a diluent (15-40%), and additives (5-35%). The oligomer is derived from polyol ("A") which has been reacted with diisocyanate ("B"), and capped with hydroxy-termin~te~ alkyl acrylate ("C"). The resulting structure is of the form C-B-A-B-C where:
"A" ~ (R1) - (R)n - (R2);
where: Rl, R2 is an OH group;
R is a combination of C, H or C, H, O;
and2<n<1000 B" ~ O=C=N-(R3~-N=C=) where: R3 is an alkyl or aromatic group ~ _ 2l 3299~
o "C"~ HO - (R4) - O - C - CH = CH2 where: R4 is an alkyl group with 2-6 carbon atoms;
Illustratively, phenoxyethylacrylate is a suitable diluent for use in the optical fiber coating of the present invention which serves to decrease the viscosity of the oligomer resin. However, decreased viscosity can also be achieved through use of an epoxy acrylate oligomer having the general structure E-D-E, inwhich case the amount of diluent used can be reduced to less than 15%. In this situation, a carboxy-tennin~ted polyol, design~ted "D", comprises the following 0 structure:
O O
Il 11 " D"~ OH - C - (R)n -C - OH
where: R is a combination of C, H or C, H, O;
and 2 S n < 1000 and a glycidyl acrylate, desi~n~tecl "E," comprises the following structure:
O O
"E"~ C - C - (Rs) - OC CH2 CH2 where: (Rs) is an alkyl group Various polyols (alcohols containing plural hydroxyl groups) may be used in the oligomer chain including:
(i) polycarbonate;
(ii) polyester;
(iii) polyether;
(iv) polybutadiene; or (v) hydrogenated polybutadiene.
Additives Selection of the proper additive to facilitate removal of the primary coating from a glass fiber without severely limiting its adhesion thereto is a non-trivial problem, particularly because both properties are required and appear to be mutually exclusive. However, as with so many such problems, cOlllplolllises are possible because there exists a region where both removability and adhesion are acceptable.
This is to say that the adhesive force need not be much greater than the highest force -8- 21329~2 _ expected during handling; nor should it be much less than the lowest force expected when the coating is being intentionally stripped from the fiber. And whereas the prior art discloses the addition of polysiloxane to enhance strippability, it has beendiscovered, much to our surprise, that the addition of hydrocarbon components to the 5 coating material, in an amount from about 1-20%, appear to cover the above-mentioned region. For example, maximum acceptable adhesion is provided when only 1% of the hydrocarbon component is added, and minimum acceptable adhesion is provided when 20% of the hydrocarbon component is added. The use of hydrocarbon components to achieve these desired results is surprising because lo formulators historically have avoided the use of non-crosslink~ble components due to anticipated and/or obseNed detrimental properties in the cured form. Additives blended into the coating material either bind to the coating material, bind to the glass after the coating material is applied, or are free to migrate. The latter type are sometimes called fugitive because they do not 15 form crosslinks. Unfortunately, many of the fugitive additives cause loss of adhesion or increased surface tack.
Among the additives, an antioxidant is present in an illustrative amount of about 0.5%, an adhesion promoter is present in an illustrative amount of 0.5-2.0%, and a photoinitiator is present in an illustrative amount of about 2%. Most 20 importantly, hydrocarbon component additives have been found to provide surprisingly beneficial effects on ribbon strippability, with an app1~p1iate degree of adhesion, when they are present in an amount 1-20%.
In a preferred embodiment of the invention, polytetrahydrofurandiol (a polyether), having the following structure, is used in forming the oligomer:
HO - (O CH2 CH2 CH2 CH2 )n ~ OH
Further, in the ~1cf~11ed embodiment of the invention, polytetrahydrofurandiol is used as the hydrocarbon component. Indeed, although not required in the present 30 invention, the preferred hydrocarbon component additive comprises the same polyol used in forming the oligomer.
Reference is now made to FIG. 5 which is a graph that illustrates the effect of aging on pullout force for a dual-coated fiber. In particular, the region which is designated as being "ACCEPTABLE" defines the amount of force needed to 35 remove the coating from a dual-coated fiber without problem. When adhesion between the coating material and the glass fiber becomes too great, as indicated by curve I, it is most difficult to remove the coating from the glass fiber withoutbreakage. Frequently, the fiber does not break, and yet some coating material remains 9 21 329~92 -attached to the glass after a portion has been removed (see e.g., FIG. 4C). Whenadhesion between the coating material and the glass fiber becomes too little, asindicated by curve III, the above-described problem of del~tnin~tion occurs which may lead to the incursion of water and consequent weakening of the glass fiber'ss tensile strength. Finally, curve II illustrates the beneficial result of adding hydrocarbon components in an amount 1-20% to the coating material. In this situation, the stripping force of the coating material is sufficiently low so that tenacious residues do not remain on the glass fiber, yet sufficiently high that del~min~tion is not a problem.
The ACCEPTABLE region is quanlitali~/ely shown in FIG. 5 based on measurements 0 of the ~llip~ g force required to remove coating materials from a dual-coated fiber as a function of time for various coating materials.
It has been observed that migration of the added hydrocarbon components is such that they may also be used in the secondary coating, albeit with reduced effectiveness. And while various embodiments of the invention have been 15 shown and described, it is recognized that modifications may be made by those of ordinary skill which are within the spirit and scope of the present invention.
Technical Field This invention relates generally to a protective coating for an optical fiber, and more particularly to a coating which can be easily removed from the optical fiber.
Back~r~nd of the Invention In the manufacture of optical fiber, a glass preform rod is suspended vertically and moved into a furnace at a controlled rate. The plero~ softens in the furnace and a glass fiber (also referred to as an optical fiber) is drawn freely from the molten end of the preform rod by a capstan located at the base of a draw tower.
o Because the surface of the glass fiber is susceptible to damage caused by abrasion, it is necessary to coat the fiber after it is drawn but before it comes into contact with any surface. Inasmuch as the application of a coating material must not damage the glass surface, the coating material is applied in a liquid state. Once applied, the coating material must solidify before the glass fiber reaches the capstan. This is typically accomplished within a brief time interval by photocuring -- a process in which the liquid coating material is converted to a solid by exposure to electromagnetic radiation.
Because the fibers are thin and flexible, they are readily bent when subjected to mechanical stresses such as those encountered during h~nt11ing or exposure to varying temperature environments. Such bends in the fiber frequentlyresult in loss that is much greater than the intrinsic loss of the fiber itself, and it has been found desirable to protect the glass fiber against such bending. Accordingly, the coating material is required to cushion the glass fiber against bends and two layers of coating materials are typically applied to the drawn optical fiber. An inner (primary) coating, having a relatively low modulus, is applied directly to the glass fiber; and an outer (secondary) coating, having a relatively high modulus, surrounds the primary coating. Together, these coatings desirably protect the inherently high tensile strength of the glass fiber so long as the primar.,v coating material remains bonded to the glass.
However, in what appears to be a contradictory requirement, it is also desirable to be able to easily strip the coating(s) from the glass fiber -- particularly when a number of fibers are bonded together in an array such as shown in U. S. Patent 4,900,126 which leads to yet another performance attribute that coating materials need to possess.
Indeed, if the coating materials cannot be cleanly and easily stripped, then splicing and connectorizing operations will be seriously hampered.
U. S. patent 4,472,021 discloses a strippable coating for an optical fiber which comprises from about 2% to about 20% of an organic polysiloxane additive having a plurality of hydroxy-termin~tçd groups which are joined to some of the silicon atoms in the polysiloxane chain by a carbon-to-silicon bond. This particular additive, however, exhibits low adhesion to the glass fiber which adversely affects the handling propcillies of the coated optical fiber during the manufacturing process. Low adhesion is a problem which, in the worst case, leads to "del~min~tion"
and the ensuing incursion of water, particularly upon exposure to high humidity,which attacks the glass surface and reduces tensile strength.
What is needed, and seemingly what is not disclosed in the prior art, is an additive for use in a coating for optical fibers which improves st~ippability while still m~int~ining a&esion to the glass fiber.
Summa~ of the Invention An optical fiber comprises a glass portion for guiding lightwaves which is covered by one or more layers of a coating material to protect the glass from abrasion. The coating material is improved by adding 1-20% by weight of a non-crosslinked hydrocarbon component to a formulation comprising: an oligomer (50-80% by weight); a diluent (less than 50% by weight); and other additives (5-35% by weight). The improved coating material is easily removed from the glass portion while m~ g good adhesion thereto during normal use and h~n~11in~.
In a plefelled embodiment of the invention, the oligomer has an overall structure C-B-A-B-C in which "A" represents a polyol, "B" represents diisocyanate, and "C" represents hydroxy-termin~ted alkyl acrylate. The hydrocarbon component has the structure Rl - (R)n - R2; where Rl, R2 comprises an aL~yl group or an OH group, and R is a combination of C, H or C, H, O.
In an alternate embodiment of the invention, the need for a diluent is substantially elimin~ted by using an oligomer having the structure E-D-E where "D"
represents a carboxy-tennin~te~l polyol, and "E" represents a glycidyl acrylate.Brief Description of the D. ~. in~
The invention and its mode of operation will be more clearly understood from the following detailed description when read with the appended drawing in which:
FIG. 1 is an end view, in cross section, of an optical fiber which includes a coating system;
FIG. 2 is a perspective view of an optical fiber ribbon showing a group of coated glass fibers bonded together with a matrix material;
FIG. 3A-3C illustrate the use of a ribbon-stripping tool showing three progressive stages in the removal of matlix and coating materials from a group of glass fibers;
FIG. 4A-4C illustrate various outcomes of the ribbon-stripping 3 213~992 -procedure; and FIG. 5 is a graph which illustrates the effect of aging on pullout force for dual-coated fiber.
Detailed Description FIG. 1 shows an end view, in cross section, of a coated optical fiber 10 comprising a glass fiber 12 surrounded by a protective coating system comprisinglayers 14, 15. It is well known to draw glassy optical fiber from a specially prepared, cylindrical preform which has been locally and symmetrically heated to a temperature of about 2000~C. As the preform is fed into and through a furnace, glass fiber 12 is 0 drawn from the molten material. A protective coating system is applied to the glass fiber 12 after it has been drawn from the preform which preferably comprises twolayers of radiation-cured polymeric m~teri~l~. An inner layer 14 contacts the glass fiber 12 at a glass-coating interface 13 and is referred to as a primary coating material.
An outer layer 15, which is referred to as a secondary coating material, surrounds the inner layer. One method of applying dual layers of coating materials to a movingglass fiber is disclosed in U.S. Patent 4,474,830 which issued on Oct. 2, 1984 to C. R.
Taylor. Another method for applying dual layers of coating materials onto glass fiber is disclosed in U.S. Patent 4,851,165 which issued on July 25, 1989 to J. A. Rennell and C. R. Taylor. By way of illustration, the typical diameter of glass fiber 12 is about 125 micrometers, while the diameter of its core 11 is generally less than 10 micrometers for single mode fibers. (Core 11 is the region where light is substantially confined during its propagation along the glass fiber's longitudinal axis by therefractive index profile of the glass fiber.) And finally, each layer of coating material has a thickness of about 30 micrometers so that the overall diameter of coated fiber 10 is approximately 250 rnicrometers.
Referring now to FIG. 2, there is shown a perspective view of an optical fiber ribbon 20 showing a group of coated glass fibers 10-10 that are held together with an ultraviolet (UV)-curable matrix bonding material 21. The group of optical fibers are disposed in a coplanar parallel array, and while only four (4) fibers are shown, such arrays typically comprise twelve (12) individual fibers. The modulus of the matrix material has a value less than that of the outer coating layer of the fiber but greater than the modulus of the inner coating layer. The matrix material 21 fills the interstices, bonds together the optical fibers, and extends to the outside boundary of the ribbon. A typical UV-curable matrix material 21 is a mixture comprising aresin, a diluent and a photoinitiator. The resin may include a diethylenic-termin~ted resin svnthesized from a reaction of a hydroxy-termin~te~l alkyl acrylate with the reaction product of a polyester of polyether polyol of molecular weight of 1000 to 6000 Dalton with an aliphatic or aromatic diisoctyanate, or a diethylenic-termin~ted -4-- ~32992 resin synthesized from the reaction of glycidyl acrylate with a carboxylic-tennin~ted polymer or polyether of molecular weight 1000 to 6000 Dalton. The diluent may comprise monofunctional or multifunctional acrylic acid esters having a molecular weight of 100 to 1000 Dalton or N-vinylpyrrolidinone. For the photoinitiator, the s composition may include ketonic compounds such as diethoxyacetophenone, acetophenone, benzophenone, benzoin, anthraquinone, and benzil dimethyl ketal. In a typical composition, the bonding matrix may include a resin (50-90%), diluents (5-40%), and a photoinitiator (1-10%). All percentages are by weight unless otherwise noted. Other bonding matrices may include a methacrylate, a UV-curing epoxide oran unsaturated polyester. More detailed information regarding bonded arrays of optical fibers is available in the aforementioned U.S. Patent 4,900,126.
Bonded arrays of optical fibers, as discussed above, are commercially available from AT&T under the tr~dçm~rk of AccuRibbon~) lightguide cable, and isespecially useful for high fiber count installations in the loop and metropolitan area networks where splicing and in~t~ tion productivity are paramount. Each ribbon comprises 12 color-coded fibers for easy identification, and as many as 12 ribbons are stacked together for high density. The ribbon stack is surrounded by a core tubewhich may also contain a filler that prevents the incursion of water in outside plant applications.
Ribbon Slri~irlg Reference is made to FIG. 3A-3C which illustrate the use of a ribbon-stripping tool such as used by splicing technicians for mass fusion splicing. FIG. 3A
shows the principal elements of the ribbon stripping tool and associated appalalus.
Ribbon 20 is placed within fiber holder 30 to facilitate h~nclling of the fiber during the 2s stripping process. The stripping tool comprises holder grip 40 and main body 50 which are used for removing the various layers that surround a bonded fiber array.
Lid 53 is closed during the stripping operation and includes an inner surface 54 which cooperates with a heated platen 51 to frictionally hold the outside jacket material surrounding the glass fibers within ribbon 20.
Referring first to F~G. 3A, fiber holder 30 is shown in its closed position around ribbon 20 which about to be inserted into the ribbon-stripping tool.
The portion of ribbon 20 which is to have its coating layers removed extends beyond the forward end of the fiber holder so that it can be captured between platen 51 and the inside surface 54 of lid 53 when the lid is closed onto the main body 50. Upon 3s closure, opposing blades 55, 56 are positioned to cut partially into opposite sides ribbon 20 so that a well-defined break in the coating material can be made. The particular tool used is electrically heated from an AC power source which is converted to 12 volts DC for use by a heater element within the main body 50. Holder grip 40 is ~ 5 - 21 3~92 adapted to capture fiber holder 30 therein when its lid 43 is closed.
FIG. 3B illustrates the movement of holder grip 40 away from the main body 50 of the ribbon-stripping tool. Guide rails 45-45 allow the holder grip to slide into engagement with the main body in a controlled manner. A heater (not shown) within the main body raises the temperature of platen 51 to a predetermined level which weakens/breaks the adhesive bond at the interface 13 between primary coating 14 and glass fiber 12 (see FIG. 1 or 2) of the various coated fibers. Illustratively, a temperature of 100~C for about 2 minutes provides acceptable results. Once the bond is weakened/broken the rest of the operation involves sliding the primary coating lo along the glass fiber surface. The ability of the primary coating to slide will depend on it sliding friction with the glass fiber. This action will determine how easily the composite (matrix 21 and coatings 14, 15) can be removed and the amount of residue that remains on the bare glass fibers. Therefore, a non-crosslinking and non-reactive additive is incorporated into the primary coating formulation which remains mobile (i.e., free to diffuse) in the primary coating after cure so that when the stripping operation is pclrolllled the additive will be present at the surface of glass fiber 12 to thereby reduce sliding friction.
Finally, FIG. 3C shows end results of the ribbon stripping process in which glass fibers 12-12 protrude from ribbon 20 which is still held within the fiber holder 30. And matrix material 21 which has just been stripped away remains on the heated platen 51 of the main body 50. Having stripped the matrix and coating materials away from the glass fibers 12-12, FIG. 4A-4C are used for illustrating the various possible results of the stripping process and for discussing their acceptability.
For example, FIG. 4A shows an ideal condition wherein the matrix 21 and coating materials 14, 15 are fully removed from the glass fibers 12-12. Such results arefrequently possible with the present invention although the presence of some residues 16-16, as shown in FIG. 4B, is also acceptable provided they can be removed by gentle wiping with an alcohol-moistened cotton swab. However, FIG. 4C illustrates an unacceptable condition in which the coating materials have clung to the glass fibers so tenaciously that either breakage occurs or large patches remain that cannot be easily removed.
Coating Materials Coating materials not only protect the glass fiber from abrasion and cushion it against microbending loss, but they also help preserve its tensile strength.
However, in order to preserve tensile strength, the coating materials must stay bonded to the glass -- at least until they are stripped off, and then it is desirable that they be fully removable without leaving a residue on the glass. More specifically, the -6- 2132~92 interface between the primary coating material and the glass fiber must be characterized by suitable strength to prevent del~min~tion, and must be such that the coating system can be stripped from the optical fiber without tenacious residues being left on the fiber surface. On the other hand, the surface of the secondary coating 5 material must be such that tacking does not occur between adjacent convolutions of the fiber, resulting in a jerky payoff from a process spool.
Typical coating materials comprise urethane acrylate liquids whose molecules become crosslinked when exposed to ultraviolet light. Various additives are also present that enhance one or more properties of the coating. For example, lo photoinitiators are added to accelerate the curing process which is important because coated optical fiber is wrapped around spools for storage as soon as it is cured, and manufacturing speed is critical to profitability.
Curing is the conversion of the liquid coating material to a solid. In the present system this process is known as free radical cure wherein, upon absorption of 1S light, the photoinitiator components cleave to form free radical pairs which diffuse away from each other and react with acrylate-terrnin~tecl components to initiate a chain polymerization process. In addition to photoinitiators, coating materials further include diluents, antioxidants, adhesion promoters and, in some cases, additives to improve strippability. However, before addressing strippability, it is important to first 20 discuss the composition of the primary coating material which makes contact with the glass surface, and whose properties are the subject of the present invention.
In the prer~-led embodiment of the invention, primary coating 14 comprises a 30 micron-thick layer of a material that surrounds glass fiber 12. It has a low modulus (e.g., 106 Pa) to cushion the glass fiber against sharp bends that cause 25 loss to a lightwave signal. The primary coating illustratively comprises an oligomer (50-80%), a diluent (15-40%), and additives (5-35%). The oligomer is derived from polyol ("A") which has been reacted with diisocyanate ("B"), and capped with hydroxy-termin~te~ alkyl acrylate ("C"). The resulting structure is of the form C-B-A-B-C where:
"A" ~ (R1) - (R)n - (R2);
where: Rl, R2 is an OH group;
R is a combination of C, H or C, H, O;
and2<n<1000 B" ~ O=C=N-(R3~-N=C=) where: R3 is an alkyl or aromatic group ~ _ 2l 3299~
o "C"~ HO - (R4) - O - C - CH = CH2 where: R4 is an alkyl group with 2-6 carbon atoms;
Illustratively, phenoxyethylacrylate is a suitable diluent for use in the optical fiber coating of the present invention which serves to decrease the viscosity of the oligomer resin. However, decreased viscosity can also be achieved through use of an epoxy acrylate oligomer having the general structure E-D-E, inwhich case the amount of diluent used can be reduced to less than 15%. In this situation, a carboxy-tennin~ted polyol, design~ted "D", comprises the following 0 structure:
O O
Il 11 " D"~ OH - C - (R)n -C - OH
where: R is a combination of C, H or C, H, O;
and 2 S n < 1000 and a glycidyl acrylate, desi~n~tecl "E," comprises the following structure:
O O
"E"~ C - C - (Rs) - OC CH2 CH2 where: (Rs) is an alkyl group Various polyols (alcohols containing plural hydroxyl groups) may be used in the oligomer chain including:
(i) polycarbonate;
(ii) polyester;
(iii) polyether;
(iv) polybutadiene; or (v) hydrogenated polybutadiene.
Additives Selection of the proper additive to facilitate removal of the primary coating from a glass fiber without severely limiting its adhesion thereto is a non-trivial problem, particularly because both properties are required and appear to be mutually exclusive. However, as with so many such problems, cOlllplolllises are possible because there exists a region where both removability and adhesion are acceptable.
This is to say that the adhesive force need not be much greater than the highest force -8- 21329~2 _ expected during handling; nor should it be much less than the lowest force expected when the coating is being intentionally stripped from the fiber. And whereas the prior art discloses the addition of polysiloxane to enhance strippability, it has beendiscovered, much to our surprise, that the addition of hydrocarbon components to the 5 coating material, in an amount from about 1-20%, appear to cover the above-mentioned region. For example, maximum acceptable adhesion is provided when only 1% of the hydrocarbon component is added, and minimum acceptable adhesion is provided when 20% of the hydrocarbon component is added. The use of hydrocarbon components to achieve these desired results is surprising because lo formulators historically have avoided the use of non-crosslink~ble components due to anticipated and/or obseNed detrimental properties in the cured form. Additives blended into the coating material either bind to the coating material, bind to the glass after the coating material is applied, or are free to migrate. The latter type are sometimes called fugitive because they do not 15 form crosslinks. Unfortunately, many of the fugitive additives cause loss of adhesion or increased surface tack.
Among the additives, an antioxidant is present in an illustrative amount of about 0.5%, an adhesion promoter is present in an illustrative amount of 0.5-2.0%, and a photoinitiator is present in an illustrative amount of about 2%. Most 20 importantly, hydrocarbon component additives have been found to provide surprisingly beneficial effects on ribbon strippability, with an app1~p1iate degree of adhesion, when they are present in an amount 1-20%.
In a preferred embodiment of the invention, polytetrahydrofurandiol (a polyether), having the following structure, is used in forming the oligomer:
HO - (O CH2 CH2 CH2 CH2 )n ~ OH
Further, in the ~1cf~11ed embodiment of the invention, polytetrahydrofurandiol is used as the hydrocarbon component. Indeed, although not required in the present 30 invention, the preferred hydrocarbon component additive comprises the same polyol used in forming the oligomer.
Reference is now made to FIG. 5 which is a graph that illustrates the effect of aging on pullout force for a dual-coated fiber. In particular, the region which is designated as being "ACCEPTABLE" defines the amount of force needed to 35 remove the coating from a dual-coated fiber without problem. When adhesion between the coating material and the glass fiber becomes too great, as indicated by curve I, it is most difficult to remove the coating from the glass fiber withoutbreakage. Frequently, the fiber does not break, and yet some coating material remains 9 21 329~92 -attached to the glass after a portion has been removed (see e.g., FIG. 4C). Whenadhesion between the coating material and the glass fiber becomes too little, asindicated by curve III, the above-described problem of del~tnin~tion occurs which may lead to the incursion of water and consequent weakening of the glass fiber'ss tensile strength. Finally, curve II illustrates the beneficial result of adding hydrocarbon components in an amount 1-20% to the coating material. In this situation, the stripping force of the coating material is sufficiently low so that tenacious residues do not remain on the glass fiber, yet sufficiently high that del~min~tion is not a problem.
The ACCEPTABLE region is quanlitali~/ely shown in FIG. 5 based on measurements 0 of the ~llip~ g force required to remove coating materials from a dual-coated fiber as a function of time for various coating materials.
It has been observed that migration of the added hydrocarbon components is such that they may also be used in the secondary coating, albeit with reduced effectiveness. And while various embodiments of the invention have been 15 shown and described, it is recognized that modifications may be made by those of ordinary skill which are within the spirit and scope of the present invention.
Claims (10)
1. A coated optical fiber 10 comprising an optical glass 12 for guiding lightwaves and an enhanced coating material 14, disposed about the optical glass, the enhanced coating material comprising 50-80% by weight of an oligomer, less than 50% by weight of a diluent, and 5-35% by weight of additives; said additives including a stabilizer, an adhesion promoter, a photoinitiator, and a non-crosslinked hydrocarbon component for improving strippability; said hydrocarbon component being present in an amount equal to 1-20% by weight..
2. The coated optical fiber 10 of claim 1 wherein the optical fiber 12includes a primary 14 and a secondary 15 layer of coating material disposed about the optical glass, the primary layer being in immediate contact with the optical glass and comprising the enhanced coating material.
3. The coated optical fiber of claim 1 wherein the enhanced coating material 14 comprises 15-40% by weight of a diluent.
4. The coated optical fiber 10of claim 3 wherein the hydrocarbon component comprises the following structure:
R1 - (R)n - R2 where: R1, R2 is an alkyl group or an OH group; and R is a combination of C, H or C, H, O; and 2~n~1000
R1 - (R)n - R2 where: R1, R2 is an alkyl group or an OH group; and R is a combination of C, H or C, H, O; and 2~n~1000
5. The coated optical fiber of claim 1 wherein the oligomer comprises the reaction product of a polyol component "A," a diisocyanate component "B," and a hydroxy-terminated alkyl acrylate "C", said oligomer having the following structure:
C-B-A-B-C.
C-B-A-B-C.
6. The coated optical fiber 10 of claim 5 wherein the polyol component of the oligomer is selected from one of the following:
(i) polyester;
(ii) polyether;
(iii) polycarbonate;
(iv) polybutadiene;
(v) hydrogenated polybutadiene.
(i) polyester;
(ii) polyether;
(iii) polycarbonate;
(iv) polybutadiene;
(v) hydrogenated polybutadiene.
7. The coated optical fiber 10 of claim 6 wherein the polyol component of the oligomer comprises polytetrahydrofurandiol.
8. The coated optical fiber 10 of claim 1 wherein the hydrocarbon component is the polyol used in forming the oligomer.
9. The coated optical fiber 10 of claim 1 wherein the enhanced coating material comprises less than 15% by weight of a diluent.
10. The coated optical fiber 10 of claim 9 wherein the oligomer comprises a carboxy-terminated polyol "D" and a glycidyl acrylate "E" having thefollowing structure: E-D-E.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US170,885 | 1993-12-21 | ||
| US08/170,885 US5373578A (en) | 1993-12-21 | 1993-12-21 | Strippable coating for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2132992A1 CA2132992A1 (en) | 1995-06-22 |
| CA2132992C true CA2132992C (en) | 1997-10-28 |
Family
ID=22621676
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002132992A Expired - Fee Related CA2132992C (en) | 1993-12-21 | 1994-09-27 | Strippable coating for optical fiber |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5373578A (en) |
| EP (1) | EP0659701B1 (en) |
| JP (1) | JP2883828B2 (en) |
| CA (1) | CA2132992C (en) |
| DE (1) | DE69405525T2 (en) |
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| CA2082614A1 (en) * | 1992-04-24 | 1993-10-25 | Paul J. Shustack | Organic solvent and water resistant, thermally, oxidatively and hydrolytically stable radiation-curable coatings for optical fibers, optical fibers coated therewith and processes for making same |
| AU712024B2 (en) * | 1995-09-07 | 1999-10-28 | Dsm N.V. | Optical glass fiber ribbon assembly and radiation curable matrix forming composition |
| US6052503A (en) * | 1995-09-07 | 2000-04-18 | Dsm N.V. | Optical glass fiber ribbon assembly and radiation curable matrix forming composition |
| US5908873A (en) * | 1995-12-20 | 1999-06-01 | Borden Chemicals, Inc. | Peelable bonded ribbon matrix material; optical fiber bonded ribbon arrays containing same; and process for preparing said optical fiber bonded ribbon arrays |
| JP2000508287A (en) * | 1996-04-10 | 2000-07-04 | デー エス エム エヌ．ヴェー． | Method for increasing the adhesion between a radiation cured inner first coating and an optical glass fiber |
| AU4969697A (en) * | 1996-11-08 | 1998-06-03 | Dsm N.V. | Radiation-curable optical glass fiber coating compositions, coated optical glass fibers, and optical glass fiber assemblies |
| US6130980A (en) * | 1997-05-06 | 2000-10-10 | Dsm N.V. | Ribbon assemblies and ink coating compositions for use in forming the ribbon assemblies |
| US6197422B1 (en) | 1997-05-06 | 2001-03-06 | Dsm, N.V. | Ribbon assemblies and radiation-curable ink compositions for use in forming the ribbon assemblies |
| US6085010A (en) * | 1997-06-11 | 2000-07-04 | Dsm N.V. | Optical glass fiber ribbon assemblies and radiation-curable compositions for use in forming ribbon assemblies |
| WO1998057209A1 (en) * | 1997-06-11 | 1998-12-17 | Dsm N.V. | Optical glass fiber ribbon assemblies, matrix forming compositions and ink coating compositions for use in forming ribbon assemblies |
| US6301415B1 (en) | 1997-08-14 | 2001-10-09 | Dsm N.V | Optical glass fiber ribbon assemblies, matrix forming compositions radiation-curable compositions |
| US5977202A (en) * | 1997-09-22 | 1999-11-02 | Dsm N.V. | Radiation-curable compositions having fast cure speed and good adhesion to glass |
| US5946986A (en) * | 1997-10-23 | 1999-09-07 | Amherst International, Inc. | Optical fiber preparation unit |
| US6391936B1 (en) | 1997-12-22 | 2002-05-21 | Dsm N.V. | Radiation-curable oligomers radiation-curable compositions, coated optical glass fibers, and ribbon assemblies |
| US6042943A (en) * | 1998-03-23 | 2000-03-28 | Alvin C. Levy & Associates, Inc. | Optical fiber containing a radiation curable primary coating composition |
| US5985952A (en) * | 1998-03-23 | 1999-11-16 | Alvin C. Levy & Associates, Inc. | Radiation curable primary coating composition for an optical fiber |
| US6110593A (en) * | 1998-05-21 | 2000-08-29 | Dsm N.V. | Radiation-curable optical fiber primary coating system |
| US6040357A (en) * | 1998-05-28 | 2000-03-21 | Dsm N.V. | Method of making a radiation-curable ink composition, radiation-curable ink composition and ribbon assembly |
| US6215934B1 (en) * | 1998-10-01 | 2001-04-10 | Lucent Technologies, Inc. | Coated optical fiber with improved strippability |
| US6253013B1 (en) * | 1999-03-29 | 2001-06-26 | Siecor Operations, Llc | Optical fiber arrays |
| US6381390B1 (en) | 1999-04-06 | 2002-04-30 | Alcatel | Color-coded optical fiber ribbon and die for making the same |
| WO2000067350A1 (en) * | 1999-04-30 | 2000-11-09 | University Of Southampton | An optical fibre arrangement |
| US6261006B1 (en) | 1999-09-24 | 2001-07-17 | Amphenol Corporation | Environmental sealing for fiber optic cable assemblies |
| US6289158B1 (en) * | 1999-11-18 | 2001-09-11 | Lucent Technologies Inc. | Coated optical fiber with enhanced delamination resistance and thermally enhanced strippability |
| US6876799B2 (en) | 2001-05-09 | 2005-04-05 | Alcatel | Gel-swellable layers on fibers, fiber ribbons and buffer tubes |
| US6714713B2 (en) * | 2002-03-15 | 2004-03-30 | Corning Cable Systems Llc | Optical fiber having a low-shrink buffer layer and methods of manufacturing the same |
| US7108431B2 (en) | 2003-04-17 | 2006-09-19 | 3M Innovative Properties Company | Ferrule for use in fiber optic connectors |
| US6973242B2 (en) | 2003-04-17 | 2005-12-06 | 3M Innovative Properties Company | Apparatus useful for guiding fiber optic ribbons into ferrules |
| US20050135763A1 (en) * | 2003-12-17 | 2005-06-23 | Gary Drenzek | Optical fiber with a mechanically strippable coating and methods of making the same |
| JP2008090040A (en) * | 2006-10-03 | 2008-04-17 | Furukawa Electric Co Ltd:The | Coated optical fiber ribbon |
| WO2019172443A1 (en) | 2018-03-08 | 2019-09-12 | 古河電気工業株式会社 | Optical fiber ribbon and optical fiber cable |
| US10689544B2 (en) | 2018-05-03 | 2020-06-23 | Corning Incorporated | Fiber coatings with low pullout force |
| US10775557B2 (en) | 2018-05-03 | 2020-09-15 | Corning Incorporated | Fiber coatings with low pullout force |
| US11105973B2 (en) | 2019-01-11 | 2021-08-31 | Schott Corporation | Optically enhanced high resolution image guides |
| EP4028811A1 (en) * | 2019-09-09 | 2022-07-20 | 3M Innovative Properties Company | Optical connector and methods of modifying optical connector |
| US11822117B2 (en) * | 2019-10-08 | 2023-11-21 | Corning Incorporated | Primary coating compositions with improved microbending performance |
| US20230193073A1 (en) * | 2020-06-24 | 2023-06-22 | Sumitomo Electric Industries, Ltd. | Resin composition, optical fiber, and method for producing optical fiber |
| JPWO2022264873A1 (en) * | 2021-06-14 | 2022-12-22 |
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| JPS58115402A (en) * | 1981-12-28 | 1983-07-09 | Nippon Telegr & Teleph Corp <Ntt> | Optical fiber core |
| US4472021A (en) * | 1982-12-10 | 1984-09-18 | Desoto, Inc. | Strippable radiation-cured coatings for optical fiber and method |
| US4474830A (en) * | 1982-12-29 | 1984-10-02 | At&T Bell Laboratories | Multiple coating of fibers |
| JPS6071550A (en) * | 1983-09-26 | 1985-04-23 | Nitto Electric Ind Co Ltd | Cladding material for optical glass fiber |
| JPS61215236A (en) * | 1985-03-15 | 1986-09-25 | Nippon Paint Co Ltd | Composition for coating optical fiber |
| US5136679A (en) * | 1985-07-23 | 1992-08-04 | U.S. Philips Corp. | Optical glass fibre having a synthetic resin coating and curable elastomer forming material |
| DE3710240A1 (en) * | 1987-03-27 | 1988-10-06 | Siemens Ag | OPTICAL GLASS FIBER WITH A PRIMARY COATING FROM ORGANOPOLYSILOXANES CONTAINING ACRYLIC ACID ESTER GROUPS |
| US4851165A (en) * | 1987-09-02 | 1989-07-25 | American Telephone And Telegraph Company At&T Bell Laboratories | Methods of and apparatus for coating optical fiber |
| US4900126A (en) * | 1988-06-30 | 1990-02-13 | American Telephone & Telegraph Co. | Bonded array of transmission media |
| CA1321671C (en) * | 1989-05-11 | 1993-08-24 | Paul J. Shustack | Ultraviolet radiation-curable coatings for optical fibers and optical fibers coated therewith |
| US5352712A (en) * | 1989-05-11 | 1994-10-04 | Borden, Inc. | Ultraviolet radiation-curable coatings for optical fibers |
| US5011260A (en) * | 1989-07-26 | 1991-04-30 | At&T Bell Laboratories | Buffered optical fiber having a strippable buffer layer |
| US5062685A (en) * | 1989-10-11 | 1991-11-05 | Corning Incorporated | Coated optical fibers and cables and method |
| US5015068A (en) * | 1990-02-15 | 1991-05-14 | At&T Bell Laboratories | Coated optical fiber and methods of making |
| US5181269A (en) * | 1991-09-17 | 1993-01-19 | At&T Bell Laboratories | Optical fiber including acidic coating system |
| JP3220221B2 (en) * | 1992-04-20 | 2001-10-22 | ジェイエスアール株式会社 | Liquid curable resin composition |
| CA2082614A1 (en) * | 1992-04-24 | 1993-10-25 | Paul J. Shustack | Organic solvent and water resistant, thermally, oxidatively and hydrolytically stable radiation-curable coatings for optical fibers, optical fibers coated therewith and processes for making same |
-
1993
- 1993-12-21 US US08/170,885 patent/US5373578A/en not_active Expired - Lifetime
-
1994
- 1994-09-27 CA CA002132992A patent/CA2132992C/en not_active Expired - Fee Related
- 1994-12-01 DE DE69405525T patent/DE69405525T2/en not_active Expired - Fee Related
- 1994-12-01 EP EP94308907A patent/EP0659701B1/en not_active Expired - Lifetime
- 1994-12-21 JP JP6335123A patent/JP2883828B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07215737A (en) | 1995-08-15 |
| CA2132992A1 (en) | 1995-06-22 |
| DE69405525T2 (en) | 1998-03-26 |
| DE69405525D1 (en) | 1997-10-16 |
| US5373578A (en) | 1994-12-13 |
| EP0659701B1 (en) | 1997-09-10 |
| JP2883828B2 (en) | 1999-04-19 |
| EP0659701A1 (en) | 1995-06-28 |
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