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Title:
POLISHING/LAPPING FILM WITH MICRO-ENCAPSULATED CHEMISTRIES PREVENTING DEBRIS ENTRAINMENT
Document Type and Number:
WIPO Patent Application WO/2018/222857
Kind Code:
A1
Abstract:
Embodiments of a polishing film are provided. The polishing film includes a substrate having a surface. Abrasive particles are attached to the surface of the substrate, and microcapsules are attached to the surface of the substrate at locations between the abrasive particles. Each of the microcapsules comprises at least one of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane. Further, methods of forming the polishing film and using the polishing film to polish an optical fiber connector are provided.

Inventors:
BOOKBINDER, Dana Craig (2675 Davis Road, Corning, New York, 14830, US)
EKWEJUNOR-ETCHIE, Ogbemi Joseph (18 Dresden Bay, Alameda, California, 94502, US)
HAMILTON, Karen Ann (210 Gray Lane, Painted Post, New York, 14870, US)
HUZINEC, Gary Michael (221 Meadow Drive, Horseheads, New York, 14845, US)
Application Number:
US2018/035370
Publication Date:
December 06, 2018
Filing Date:
May 31, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CORNING RESEARCH & DEVELOPMENT CORPORATION (1 Riverfront Plaza, Corning, New York, 14831, US)
International Classes:
B24B37/24; B24D3/34; B24D11/00; C09K3/14
Domestic Patent References:
WO2002038338A22002-05-16
Foreign References:
EP1078717A22001-02-28
US5725617A1998-03-10
US4112631A1978-09-12
US3502453A1970-03-24
EP0748659A21996-12-18
Other References:
DATABASE WPI Week 199249, Derwent World Patents Index; AN 1992-403093, XP002783620
None
Attorney, Agent or Firm:
WEEKS, Adam R. (CORNING OPTICAL COMMUNICATIONS LLC, Intellectual Property DepartmentSP-TI-3-, Corning New York, 14831, US)
Download PDF:
Claims:
What is claimed is:

1. A polishing film, comprising:

a substrate having a surface;

abrasive particles attached to the surface of the substrate; and

microcapsules attached to the surface of the substrate at locations between the abrasive particles, each of the microcapsules comprising at least one of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane.

2 The polishing film of claim 1, wherein at least some of the microcapsules comprise at least one silane, and wherein the at least one silane is represented by the general structural formula of:

wherein a + b + c + d = 4, and 1 < d < 4, and R1, R2, and R3 are each a hydrocarbon or fluorocarbon of an alkyl, a branced, an unbranched, a phenylated, or a cylic structure; and

wherein X is -OH, -halide, or -0-alkyl.

3. The polishing film of either claim 1 or 2, wherien at least some of the

microcapsules comprise at least one silicon-containing cationic ammonium compound, and wherein the at least one silicon-containing catioinic ammonium compound comprises a tetraalkylammonium chloride alkyltrialkoxysilane, octadecyldimethyl-(3-trimethoxysilyl- propyl) ammonium chloride, or N,N-didecyl-N-methyl-N-(3-trimethoxysilyl-propyl)ammonium chloride.

4. The polishing film of any of claims 1-3, wherein at least some of the microcapsules comprise at least one siloxane, and wherein the at least one siloxane is trimethylpolydimethylsiloxanol having from 6 to 50 repeating units.

5. The polishing film of any of claims 1-4, wherein the microcapsules are arranged on a majority area of the surface of the substrate such that the microcapsules comprise from 5 to 70 vol% of materials deposited on the majority area of the surface.

6. The polishing film of claim 5, wherein the abrasive particles are arranged on the majority area of the surface of the substrate such that the abrasive particles comprise from 5 to 70 vol% of the materials deposited on the majority area of the surface.

7. The polishing film of any of claims 1-6, further comprising:

a polymer bonding matrix adhered to the surface of the substrate, wherein the microcapsules and the abrasive particles are attached to the surface of the substrate by the polymer bonding matrix.

8. The polishing film of claim 7, wherein:

the microcapsules are arranged on a majority area of the surface of the substrate such that the microcapsules comprise from 5 to 70 vol% of materials deposited on the majority area of the surface;

the abrasive particles are arranged on the majority area of the surface of the substrate such that the abrasive particles comprise from 5 to 70 vol% of the materials deposited on the majority area of the surface; and

the polymer bonding matrix comprises a remainder vol% of the materials deposited on the majority area of the surface.

9. The polishing film of any of claims 1-8, wherein at least some of the microcapsules comprise at least one lubricant, and wherein the at least one lubricant comprises hexagonal boron nitride, molybdenum disulfide, polytetrafluoroethylene, or graphite.

10. The polishing film of any of claims 1-9, wherein at least a some of the microcapsules comprise at least one surfactant, and wherein the at least one surfactant comprises alkali alkyl sufate, ammonium alkyl sulfate, alkali alkylbenzene sulfonate, ammonium alkali alkylbenzene sulfonate, ammonium alkylbenzene sulfonate, C8-to-C2o alkyl ammonium chloride, C8-to-C2o alkyl ammonium bromide, C8-to-C2o alkyl ammonium hydroxide, C8-to-C2o alkyl ammonium acetate, C8-to-C2o alkyl ammonium sulfate, ethyloxylated- or propoxylated- alkyl phenols, ethyloxylated- or propoxylated- C8-to-C2o alcohols, or ethyloxylated- or propoxylated- C8-to-C2o acids.

11. The polishing film of any of claims 1-10, wherein the microcapsules have an average outer dimension of between 50 nm and 2 mm

12. The polishing film of any of claims 1-11, wherein the microcapsules each include a shell made from at least one of the following: alkyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, polyvinyl alcohol, gelatin, or sodium alginate.

13. The polishing film of any of claims 1-12, wherein the at least one of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane of at least some of the microcapsules is different than the at least one of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane of other of the microcapsules.

14. The polishing film of any of claims 1-13, wherein the microcapsules have on average a core volume of at least 500,000 nm3.

15. The polishing film of any of claims 1-14, wherein the substrate is made from at least one of the following: a polyethylene terephthalate, a polyester, biaxially-oriented polyethylene terephthalate, a polyolefm, a polycarbonate, a polyacrylate, a polyethylene, a polyurethane, or an epoxy.

16. A method of forming a polishing film, the method comprising the steps of:

depositing abrasive particles onto a substrate;

depositing microcapsules onto the substrate between the abrasive particles, the microcapsules comprising one or more of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane; and

binding the abrasive particles and the microcapsules to the substrate.

17. The method of claim 16, wherein the step of depositing microcapsules further comprises depositing the microcapsules such that the microcapsules comprise from 5 to 70 vol% of materials deposited onto a majority area of the substrate.

18. The method of claim 17, wherein the step of depositing abrasive particles further comprises depositing the abrasive particles such that the abrasive particles comprise from 5 to 70 vol% of the materials deposited onto the majority area of the substrate.

19. The method of any of claims 16-18, further comprising the step of including at least one of:

a silane that is represented by the general structural formula of:

wherein a + b + c + d = 4, and 1 < d < 4, and R1, R2, and R3 each is a hydrocarbon or fluorocarbon of either an alkyl, branced, unbranched, phenylated, or cylic structure; and

wherein X is -OH, -halide, or -O-alkyl; or a tetraalkylammonium chloride alkyltrialkoxysilane, octadecyldimethyl-(3- trimethoxysilyl-propyl)ammonium chloride, N,N-didecyl-N-methyl-N-(3-trimethoxysilyl- propyl) ammonium chloride, or trimethylpolydimethylsiloxanol having from 6 to 50 repeating units; or

hexagonal boron nitride, molybdenum disulfide, polytetrafluoroethylene, or graphite; or alkali alkyl sufate, ammonium alkyl sulfate, alkali alkylbenzene sulfonate, ammonium alkali alkylbenzene sulfonate, ammonium alkylbenzene sulfonate, C8-to-C2o alkyl ammonium chloride, C8-to-C2o alkyl ammonium bromide, C8-to-C2o alkyl ammonium hydroxide, C8-to-C2o alkyl ammonium acetate, C8-to-C2o alkyl ammonium sulfate, ethyloxylated- or propoxylated- alkyl phenols, ethyloxylated- or propoxylated- C8-to-C2o alcohols, or ethyloxylated- or propoxylated- C8-to-C2o acids.

20. The method of any of claims 16-19, wherein the microcapsules deposited onto the substrate have on average a maximum outer dimension of between 50 nm and 2 mm.

21. The method of any of claims 16-20, whereinat least some of the microcapsules deposited onto the substrate each comprise at least one different lubricant, surfactant, silane, silicon-containing cationic ammonium compound, or siloxane than a second portion of microcapsules on the film.

22. A method of polishing an optical fiber connector, wherein the optical fiber connector includes a ferrule through which at least one optical fiber extends, the method comprising the steps of:

positioning the ferrule relative to a surface of a polishing film such that an end face of the at least one optical fiber faces the polishing film, wherein the surface of the polishing film includes abrasive particles and microcapsules, and wherein each of the microcapsules comprises one or more of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane;

causing the polishing film to contact the ferrule and the optical fiber; and moving the ferrule and the optical fiber across the polishing film to abrade the ferrule, the optical fiber, or both the ferrule and the optical fiber, wherein the moving also causes a plurality of the microcapsules to rupture.

23. The method of claim 22, wherein the rupture of the microcapsules comprises releasing the one or more of the lubricant, the surfactant, the silane, the silicon-containing cationic ammonium compound, or the siloxane into an interface between the polishing film and both the ferrule and the optical fiber.

24. The method of claim 23, wherein the rupture of the microcapsules comprises coating grinding debris produced during the step of moving the ferrule and the optical fiber across the polishing film.

25. The method of any of claims 22-24, wherein the method does not include a step of spraying a polishing liquid onto the polishing film.

26. The method of any of claims 22-25, further comprising the step of using abrasive particles comprised of silica and having on average a size of between 0.1 μη and 0.01 μη to remove pits and scratches from the end face of the optical fiber that extends through the ferrule such that the end face is able to pass IEC 61300-3-35.

Description:
POLISHING/LAPPING FILM WITH MICRO-ENCAPSULATED CHEMISTRIES PREVENTING DEBRIS ENTRAINMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/513728, filed on June 1, 2017, and is incorporated herein by reference in its entirety.

BACKGROUND

[0002] The disclosure relates generally to polishing films and processes and more particularly to embodiments of abrading/polishing films containing microcapsules that increase lubricity and facilitate removal of grinding debris from the film when polishing an object, such as an optical fiber connector.

[0003] Optical fibers are useful in a wide variety of applications, including the

telecommunications industry for voice, video, and data transmissions. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables that carry the optical fibers connect to equipment or other fiber optic cables. To conveniently provide these connections, optical fiber connectors ("connectors") are often provided on the ends of fiber optic cables. The process of terminating individual optical fibers from a fiber optic cable with a connector is referred to as "connectorization." Connectorization can be done in a factory, resulting in a "pre-connectorized" or "pre-terminated" fiber optic cable, or the field (e.g., using a "field- installable" connector).

[0004] Regardless of where installation occurs, an optical fiber connector typically includes a ferrule with one or more bores that receive one or more optical fibers. The ferrule supports and positions the optical fiber(s) with respect to a housing of the fiber optic connector. Thus, when the housing of the fiber optic connector is mated with another connector (e.g., in an adapter), an optical fiber in the ferrule is positioned in a known, fixed location relative to the housing. This allows an optical connection to be established when the optical fiber is aligned with another optical fiber provided in the mating connector. [0005] The bore of the ferrule in an optical fiber connector may extend from a rear of the ferrule to a front of the ferrule. With such a design, an optical fiber can be passed through the ferrule so as to extend beyond an end face at the front of the ferrule. After securing the optical fiber relative to the ferrule (e.g., by using a bonding agent in the bore), an optical surface may be formed on the optical fiber. The optical surface is typically formed a precise distance from the end face of the ferrule according to very tight dimensional standards to reduce signal attenuation. For example, the optical surface of the optical fiber may need to be formed within a few microns of the end face of the ferrule.

[0006] One conventional method of forming an optical surface involves a cleaving step followed by several mechanical polishing steps. Such methods can be time-consuming and labor-intensive due to the number of polishing steps required to form the optical surface within a few microns of the end face of the ferrule. For example, it may be necessary to begin with coarse grit when mechanically polishing and switch to finer grits in subsequent polishing steps to carefully control the distance of the end of the optical fiber from the end face of the ferrule and to form an optical surface of high quality. Switching between polishing films may also be necessary because debris from the polishing process may become entrapped on the polishing film and/or between the polishing film and optical fiber, thereby reducing the polishing film's effectiveness (e.g., material removal rate). The debris also has the potential to scratch or otherwise damage the end face of the optical fiber and/or the end face of the ferrule.

SUMMARY

[0007] In one aspect, embodiments of a polishing film are provided. The polishing film includes a substrate having a surface. Abrasive particles are attached to the surface of the substrate, and microcapsules are attached to the surface of the substrate at locations between the abrasive particles. Each of the microcapsules comprises (e.g., contains) at least one of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane.

[0008] In another aspect, embodiments of a method of forming a polishing film are provided. The method includes the steps of depositing abrasive particles onto a substrate, depositing microcapsules onto the substrate between the abrasive particles, and binding the abrasive particles and the microcapsules to the substrate. The microcapsules comprise one or more of a lubricant, a surfactant, a silane, a silicon-containing cationic ammonium compound, or a siloxane.

[0009] In still another aspect, embodiments of a method of polishing an optical fiber connector are provided. The optical fiber connector includes a ferrule through which at least one optical fiber extends. The method includes a step of positioning the ferrule relative to a surface of a polishing film such that an end face of the at least one optical fiber faces the polishing film. The surface of the polishing film includes abrasive particles and microcapsules. Each of the microcapsules comprises one or more of a lubricant, a surfactant, a silane, a silicon- containing cationic ammonium compound, or a siloxane. The method also includes the steps of causing the polishing film to contact the ferrule and the optical fiber, and moving the ferrule and the optical fiber across the polishing film to abrade the ferrule, the optical fiber, or both the ferrule and the optical fiber. Further, the moving causes a plurality of the microcapsules to rupture.

[0010] Additional features and advantages will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

[0011] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.

[0012] The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0014] FIG. 1 is a perspective view an optical fiber connector that has been polished using a polishing film made according to an exemplary embodiment;

[0015] FIG. 2 is an exploded, perspective view of the optical fiber connector of FIG. 1 , according to an exemplary embodiment;

[0016] FIG. 3 is a close-up, schematic view of a ferrule of an optical fiber connector that has been polished using a polishing film made according to an exemplary embodiment;

[0017] FIG. 4 is a schematic, perspective view a polishing film with microcapsules, according to exemplary embodiments;

[0018] FIG. 5 is a schematic, cross-sectional view of the polishing film of FIG. 4, according to an exemplary embodiment; and

[0019] FIG. 6 is a schematic representation of a polishing method using a polishing film containing microcapsules, according to exemplary embodiments.

[0020] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

[0021] Various embodiments will be further clarified by examples in the description below. In general, the description relates polishing films and processes that may be used to polish objects such as optical fibers and optical fiber connectors. In embodiments of the polishing film, microcapsules comprising (e.g., containing) one or more lubricants, surfactants, silanes, silicon-containing cationic ammonium compounds, siloxanes, etc. are dispersed among abrasive particles on the polishing film. During an abrading/polishing process, the microcapsules rupture, releasing their contents in direct contact with the object being abraded/polished. In this way, the polishing film is lubricated, and grinding debris created during abrading/polishing is coated or otherwise lubricated so as to facilitate its removal from areas where it has embedded between the abrasive particles. Accordingly, in some

embodiments, the microcapsules may help to avoid clogging of the polishing film with grinding debris, thereby enhancing the effectiveness and reusability of the polishing film.

[0022] Polishing films according to this disclosure may be particularly applicable to the connectorization of optical fiber cables. Embodiments of the polishing film will be described below in the context of such connectorization merely to facilitate discussion, and the polishing film may be referred to as a "lapping film". However, the polishing film can be used in other applications in which a surface is abraded, including, for example, preparation of medical, optical, electronic, and aerospace components.

[0023] With this in mind, one example of an optical fiber connector 10 (also referred to as "fiber optic connector", "optical connector", "optical fiber connector", or simply "connector") is shown in FIG. 1, with an exploded view of the connector 10 being provided in FIG. 2.

Although the connector 10 is shown in the form of a SC-type connector, the polishing films and processes described below may be applicable to different connector designs (e.g., other single fiber connectors, such as ST and/or LC-type connectors, or multifiber connectors, such as MPO-type connectors). Even more generally, as previously mentioned, the polishing films and processes described below may be applicable to other objects requiring abrasion/polishing.

[0024] As shown in FIGS. 1 and 2, the connector 10 includes a ferrule 22, a ferrule holder 28 from which the ferrule 22 extends, a housing 12 having a cavity in which the ferrule holder 28 is received, and a connector body 14 configured to retain the ferrule holder 28 within the housing 12. The connector body 14 may also be referred to as "retention body 14" or "crimp body 14". One portion of the connector body 14 is received in the housing 12. Another portion of the connector body 14 is received by a crimp band 16 (also referred to as "crimp ring 16"). A strain relief assembly 18 is positioned over the crimp band 16, with the strain relief assembly 18 further receiving a fiber optic cable 20 (hereinafter "cable 20"). FIG. 2 shows various components of the connector 10 including (and spanning between) the connector body 14 and the housing 12, but omits the crimp band 16, the strain relief assembly 18, and the cable 20 for simplicity of illustration. Persons skilled in optical connectivity will appreciate how a cable 20 according to various different cable designs may be terminated with the connector 10.

[0025] Still referring to FIGS. 1 and 2, the ferrule 22 includes a ferrule bore 24 (or "micro- hole") configured to support an optical fiber 26, which is secured in the ferrule bore 24 using an adhesive (e.g., epoxy). The ferrule holder 28 includes a ferrule holder bore 30 from which the ferrule 22 extends. More specifically, a back end 34 of the ferrule 22 is received in the ferrule holder bore 30 defined in (at least) a first portion 36 of the ferrule holder 28, and is secured therein in a known manner (e.g., press-fit, adhesive, molding the ferrule holder 28 over the back end 34 of the ferrule 22, etc.). The ferrule 22 and ferrule holder 28 may even be a monolithic structure in some embodiments. Notably, FIG. 1 shows the ferrule 22 as being transparent in character to illustrate the ferrule bore 24, but it is to be understood that the ferrule 22 may be fabricated of an opaque material as shown in FIG. 2.

[0026] FIG. 3 depicts a closer view of the ferrule 22, including an end face 40 of the optical fiber 26 that extends past an end face 41 of the ferrule 22. Because cleaving the optical fiber 26 produces a rough end- face of the optical fiber 26, the end face 40 is abraded and polished until the end face 40 has a desired quality, geometry, and/or location relative to ferrule 22, e.g., until the optical fiber 26 is within a few microns (e.g., less than 15 microns) of the end face 41 of the ferrule 22. This allows the optical fiber 26 to make direct physical contact with an opposing optical fiber of a mating connector (not shown) or equipment into which the optical fiber connector 10 is inserted. Further, a spring 38 (as shown in FIG. 2) provides a constant spring force pushing the ferrule 22, and consequently the optical fiber 26, to also help ensure the mating optical fibers remain in physical contact. During abrading and polishing of the optical fiber 26, the ferrule 22 is also abraded and polished to a desired shape/finish. Common shapes/finishes ("polishing types") include physical contact (PC), ultra physical contact (UPC), and angled physical contact (APC). The abrading and polishing of the ferrule 22 typically creates a radius of curvature on the end face 41 of the ferrule 22 (e.g., proximate a rim or edge 48 of the end face 41). In some embodiments, the radius of curvature may be between 7 mm (solid line) and 25 mm (dashed line). The radius of curvature on the end face 41 helps ensure that the optical fiber 26 at the center of the ferrule 22 is the forward most part of the optical fiber connector 10 such that the direct physical contact can be made at the optical fiber 26 with the optical fiber of the equipment into which the optical fiber connector 10 is inserted. In this regard, the physical contact facilitates a high fidelity optical connection between opposing optical fibers.

[0027] The ferrule 22 and optical fiber 26 are abraded and polished using a polishing film 42 as shown in FIG. 4. On its surface, the polishing film 42 includes abrasive particles 44 as well as microcapsules 46. The abrasive particles 44 remove and polish the end face 40 of the optical fiber 26 that extends past the ferrule 22, and the microcapsules 46 provide lubrication during the abrading process and facilitate removal of grinding debris (including ferrule and optical fiber material) from the abrading area. In this way, the polishing film 42 does not become clogged with the grinding debris, which would otherwise reduce the effectiveness of the polishing film 42.

[0028] During abrading, polishing films 42 having abrasive particles 44 of different sizes are used to grind and then polish the optical fiber 26. For example, in an embodiment of a coarse polishing film, the polishing film 42 may have abrasive particles 44 with an average particle size of 60 microns (as used herein, "particle size" refers to the maximum outer dimension of a particle). In an example embodiment of a fine polishing film, the polishing film 42 may have abrasive particles 44 with an average particle size of 0.01 microns (μη ). During the abrading process, polishing films 42 having average particle sizes between 60 μη and 0.01 μη may be sequentially employed going from courser- to finer- sized abrasive particles 44.

[0029] In general, after a final polish using a polishing film 42 with an average particle size of 0.02 μη , the end face 40 of the optical fiber 26 that extends through the ferrule 22 will be substantially free from pits and scratches. In this regard, a polished end face 40 is considered to be substantially free from pits and scratches if it passes International Electrotechnical Commission (IEC) standard 61300-3-35.

[0030] Suitable materials for use as abrasive particles 44 include silica, silicon carbide, diamond, alumina, cerium oxide, cubic born nitride, zirconia, tungsten carbide, etc. However, this list of materials for the abrasive particles 44 is not exhaustive and is not intended to limit the type of abrasive particles 44 used on the polishing film 42 disclosed herein; other materials may also be suitable depending on the particular application and item being abraded/polished. [0031] The microcapsules 46 generally have a structure including an outer shell and a core. The outer shell may, for example, comprise alkyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, polyvinyl alcohol, gelatin, or sodium alginate. The core of the microcapsules 46 comprises one or more lubricants, surfactants, silanes, silicon-containing cationic ammonium compounds, or siloxanes, etc. that facilitate removal of grinding debris from the polishing film 42. In this way, the microcapsules 46 provide lubricity and/or the capacity to coat grinding debris, preventing the grinding debris from adhering to the polishing film 42. In some embodiments, the core of the microcapsules 46 may include a solid, liquid, or a dispersion of solids in a liquid. Further, the microcapsules 46 may be dispersed within a polymer bonding matrix adhered to the surface of the polishing film 42.

[0032] In some embodiments, the abrasive particles 44, microcapsules 46, and polymer bonding matrix are present on a majority area of the surface of the substrate 50 (i.e., on an area of the surface of the substrate 50 that represents at least 50% of the total area of the surface) in the following volume percentage (vol%) ranges: abrasive particles 5-70 vol%; polymer bonding matrix 25-90 vol%; and microcapsules 5-70 vol%. An exemplary composition having a minimum of abrasive particles, a minimum of microcapsules, and a maximum of polymer bonding matrix includes 5 vol% abrasive particles, 90 vol% polymer bonding matrix, and 5 vol% microcapsules. An exemplary composition having a minimum of polymer bonding matrix, a minimum of microcapsules, and a maximum of abrasive particles includes 70 vol% abrasive particles, 25 vol% polymer bonding matrix, and 5 vol% microcapsules. An exemplary composition having a minimum of abrasive particles, a minimum of polymer bonding matrix, and a maximum of microcapsules includes 5 vol% abrasive particles, 25 vol% polymer bonding matrix, and 70 vol% microcapsules. Other compositions falling within the recited ranges may also be used, and the composition can be optimized depending on the polishing application and desired end result.

[0033] During the abrading process, the action of moving an object over the polishing film 42 will rupture at least some of the microcapsules 46, thereby releasing the lubricants, surfactants, silanes, silicon-containing cationic ammonium compounds, siloxanes, etc.

Advantageously, because the surface of the object being abraded/polished is rupturing the microcapsules 46, the contents of the microcapsules 46 are released directly in the area where the grinding debris is being deposited. Accordingly, the effectiveness of the lubricants, surfactants, silanes, silicon-containing cationic ammonium compounds, siloxanes, etc. is enhanced, especially as compared to other polishing techniques that utilize a polishing liquid sprayed from outside the grinding interface.

[0034] In some embodiments, the microcapsules 46 have on average a maximum outer dimension of 50 nanometers (nm) to 2 millimeters (mm). In other embodiments, the microcapsules 46 have on average a maximum outer dimension of 100 nm to 500 nm. In still other embodiments, the microcapsules 46 are selected to have on average a maximum outer dimension that is within +/- 10% of the average size of the abrasive particles 44 on the particular polishing film 42 on which both are dispersed.

[0035] In some embodiments, the shell of the microcapsule 46 may be made of a natural or synthetic polymer and/or ceramic. Exemplary materials for the shell of the microcapsule 46 include alkyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, polyvinyl alcohol, gelatin, sodium alginate, etc. In some embodiments, the core of the microcapsules 46 may comprise one or more of the following: a polishing fluid, a surfactant, or a solid lubricant. As used herein, the term "polishing fluid" means a fluid designed to bind to grinding debris in order to facilitate its removal from a polishing area. In embodiments, the polishing fluid may be suspension of an additive, such as a silane, a silicon-containing cationic ammonium compound, and/or a siloxane, in a fluid, such as water (e.g., distilled or deionized water). The term "surfactant" as used herein is a compound that lowers the surface tension of a liquid and contains both hydrophobic groups and hydrophilic groups. Thus, the surfactant contains both a water insoluble component and a water soluble component. As used herein, the term "solid lubricant" means any solid used between two surfaces to provide protection from damage during relative movement and/or to reduce friction and wear.

[0036] In an exemplary embodiment in which the polishing fluid contains a silane, preferable silanes have the general structural formula:

[0037] wherein a+b+c+d = 4, and 1 < d < 4, and R 1 , R 2 , and R 3 are each a hydrocarbon or fluorocarbon of an alkyl, branched, unbranched, phenylated, or cyclic structure and X is selected from the following: -OH, -O-alkyl, or -halide. Specific examples of such silanes and siloxanes include n-decyldimethylchlorosilane, n-decylmethyldichlorosilane, n- decyltrichlorosilane, n-decyltriethyoxysilane, cyclohexyldimethylchlorosilane,

cyclohexylethyldimethoxysilane, cyclohexylmethyldichlorosilane,

cyclohexymethyldimethoxysilane, (cyclohexylmethyl)trichlorosilane,

cyclohexyltrichlorosilane, cyclohexyltrimethoxysilane, diethyldichlorosilane,

diethyldiethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, diphenylchlorosilane, diphenyldichlorosilane, diphenyldiethoxysilane, diphenyldimethoxysilane,

dodecyldimethylchlorosilane, dodecylmethyldichorlosilane, dodecylmethyldiethoxysilane, dodecyltrichlorosilane, dodecyltriethoxysilane, n-hexadecyltrichlorosilane,

hexadecyltrimethoxysilane, triethylsilane, trimethylmethoxysilane, 3-(p- methoxyphenyl)propyltrichlorosilane, 3-methoxypropyltrimethoxysilane,

2[methoxy(polyethyleneoxy)propyl]trimethoxysilane, 3-methoxypropyltrimethoxysilane, n- octadecylmethoxydichlorosilane, n-octadecylmethyldichlorosilane, n- octadecylmethyldiethoxysilane, n-oxtadecyldimethylchlorosilane, n-octadecyltrichlorosilane, n- octadecyltriethoxysilane, n-oxtadcyltrimethoxysilane, n-octadecyldimethylmethoxysilane, n- octadcyldimethyl-(dimethyl-(dimethylamino)-silane, or bis(2-hydroxyethyl)-3 -aminopropyl- triethoxysilane. In another exemplary polishing fluid, the polishing fluid comprises a cationic ammonium compound, such as a tetraalkylammonium chloride alkyltrialkoxysilane, octadecyldimethyl-(3-trimethoxysilyl-propyl)ammonium chloride, or N,N-didecyl-N-methyl- N-(3-trimethoxysilyl-propyl)ammonium chloride. In still another exemplary polishing fluid, the polishing fluid comprises a siloxane, such as trimethylpolydimethylsiloxanol [(CH3)3-Si-0- (Si-(CH3)2-0) n -Si-(CH3)-OH; where n = 6 to 50]. These examples of possible compounds are provided by way of example only and should not be considered limiting. A person of ordinary skill in the art, after considering the present disclosure, may recognize other suitable silanes, silicon-containing cationic ammonium compounds, and siloxanes.

[0038] In an exemplary embodiment, the lubricant may be hexagonal boron nitride, molybdenum disulfide, polytetrafluoroethylene, graphite, etc. These lubricants are provided by way of example only and should not be considered limiting. A person of ordinary skill in the art, after considering the present disclosure, may recognize other suitable lubricants. In another exemplary embodiment, the surfactant may be alkali alkyl sufate, ammonium alkyl sulfate, alkali alkylbenzene sulfonate, ammonium alkali alkylbenzene sulfonate, ammonium

alkylbenzene sulfonate, C8-to-C2o alkyl ammonium chloride, C8-to-C2o alkyl ammonium bromide, C8-to-C2o alkyl ammonium hydroxide, C8-to-C2o alkyl ammonium acetate, C8-to-C2o alkyl ammonium sulfate, ethyloxylated- or propoxylated- alkyl phenols, ethyloxylated- or propoxylated- C8-to-C2o alcohols, or ethyloxylated- or propoxylated- C8-to-C2o acids. These surfactants are provided by way of example only and should not be considered limiting. A person of ordinary skill in the art, after considering the present disclosure, may recognize other suitable surfactants.

[0039] The microcapsules 46 can be manufactured in a variety of suitable ways, including, for example, pan coating, air-suspension coating, centrifugal extrusion, vibrational nozzle, spray-drying, ionotripic gelation, coacervation-phase separation, interfacial polycondensation, interfacial cross-linking, in situ polymerization, and matrix polymerization.

[0040] Further, in one specific embodiment, all of the microcapsules 46 on a single polishing film 42 contain the same core material or combination of materials. However, in other embodiments, at some of microcapsules 46 on a single polishing film 42 contain a different material or combination of materials than the remaining microcapsules 46 on the lapping film. In this way, microcapsules 46 containing different materials can be mixed and matched to achieve a specific set of properties on a single polishing film 42, and a potentially wide variety of materials can be brought into direct contact with the object being abraded/polished.

Additionally, in some embodiments, the microcapsules 46 may have on average a minimum core volume of at least 500,000 nm 3 . In other embodiments, the microcapsules 46 have on average a minimum core volume between 500,000 nm 3 and 1 μη 3 or of at least 1 μη 3 , and in still other embodiments, the microcapsules 46 have on average a minimum core volume between 1 μη 3 and 10 mm 3 or of at least 10 mm 3 .

[0041] As shown in the schematic cross-sectional view of FIG. 5, the abrasive particles 44 are illustrated as black triangles whereas the microcapsules 46 are illustrated as white circles. As schematically illustrated in FIG. 5, the abrasive particles 44 and the microcapsules 46 are dispersed across the surface of the polishing film 42. In particular, the abrasive particles 44 and microcapsules 46 are bound to a surface of a substrate 50. The substrate 50 may comprise, for example, a polyethylene terephthalate, a polyester, biaxially-oriented polyethylene

terephthalate, a polyolefin, a polycarbonate, a polyacrylate, a polyethylene, a polyurethane, or an epoxy, and in some embodiments, the substrate 50 may have a thickness of 40 to 70 μη . Further, in some embodiments, the abrasive particles 44 and microcapsules 46 may be bound to the surface of the substrate 50 using a polymeric resin (i.e., the polymer bonding matrix), such as a polyester, a copolyester, an epoxy, etc. In embodiments of the polishing film 42 constructed with the previously described components, the polishing film 42 will may a total thickness of between 45 and 150 μη .

[0042] As discussed previously and as is shown schematically in FIG. 6, one particular application of the polishing film 42 is for polishing the optical fiber 26 of an optical fiber connector 10. In FIG. 6, the polishing film 42 is supported on a compliant pad 52, i.e., the pad 52 is has some give when a force is applied to it. Similar to FIG. 5, in FIG. 6 the abrasive particles 44 are illustrated as black triangles, while the microcapsules 46 are illustrated as white circles. After positioning the polishing film 42 on the pad 52, the end face 41 of the ferrule 22 and end face 40 of the optical fiber 26 are placed onto the polishing film 42. A force 54 normal or substantially normal to the plane of the polishing film 42 and pad 52 is applied to the optical fiber connector 10, and the optical fiber connector 10 is moved over the polishing film 42 in such a manner that the sum of the force vectors is zero or approximately zero. In some embodiments, a polishing fluid (represented by arrow 56) may be sprayed onto the polishing film 42 during the abrading/polishing process so as to further assist in the removal of grinding debris from the polishing film 42. As an example, the polishing fluid 56 may be deionized (DI) or distilled water in some embodiments, and in other embodiments, the polishing fluid 56 alternatively or additionally comprise tetraalkylammonium chloride alkyltrialkoxysilane. After the ferrule 22 is moved over a single polishing film 42 or a series of polishing films 42, the end face 40 of the optical fiber 26 in the ferrule 22 will become suitable for a satisfactory data transmission connection.

[0043] Embodiments of the polishing film 42 disclosed herein provide several advantages to abrading/polishing processes. In particular, the microcapsules 46 extend the life of the polishing film 42 by increasing lubricity and decreasing factional forces on the polishing film 42. Further, the microcapsules 46 extend the life of the polishing film 42 by helping to avoid the buildup of grinding debris on the polishing film 42. That is, in embodiments, the contents of the microcapsule 46 coat the grinding debris such that it can be washed away. Additionally, buildup of grinding debris between abrasive particles 44 reduces the exposure of the abrasive particles 44, thereby reducing the abrasion effectiveness and increasing the time required to abrade/polish the optical fiber 26. Still further, the coating effect of the microcapsule 46 also helps to avoid scratching of the optical fiber 26 by, e.g., the harder zirconia material of the ferrule 22 that is ground off the end face 41 during the abrading process. Moreover, the coating and lubrication effect is enhanced because the microcapsules 46 are located at the interface of the polishing film 42 and the object being abraded/polished. Contrarily, in some applications using only a polishing fluid, the polishing fluid is largely unable to reach this interface because the ferrule 22 is pressed into the compliant pad 52, effectively sealing off the end face 40 of the optical fiber 26 from the polishing fluid.

[0044] Overall, embodiments of the polishing film 42 with microcapsules 46 disclosed herein have increased usable life and enhance the speed with which an abrading/polishing process can be performed. Further, chemicals used in the polishing process are much less likely to become aerosolized as a result of the movement of the object being abraded/polished over the polishing film 42. Finally, as mentioned above, the microcapsules 46 can be included in other abrading/polishing films for use in lapping and finishing of electronic, medical, optical, and aerospace components, including components made of carbides, ceramics, hardened metals, exotic alloys, and/or composites.

[0045] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article "a" is intended to include one or more than one component or element, and is not intended to be construed as meaning only one. [0046] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.