Title of Invention

PREMISES CABLE WITH GLASS FIBER REINFORCEMENT AND METHOD OF MAKING THEREOF

Abstract

It is thus an object of the present invention to provide a method for reducing or eliminating the possibility of fire or smoke generation in reinforcement fibers used in premises cables while maintaining the structural and protection attributes of the reinforcement fibers used in indoor communication cables. The above object is accomplished by replacing the polyaramid fibers typically found in premises cables with a sized glass reinforcement fiber. As the glass fibers are inorganic, not organic, these fibers would reduce the possibility of fire or smoke generation within the premises cable. This is especially beneficial for indoor communication cables such as a premises cable that are used in commercial or residential buildings.

Full Text

PREMISES CABLE GIVE SPACE WITH GLASS FIBER REINFORCEMENT AND METHOD OF MAKING THEREOF TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION The present invention relates generally to indoor communication cables and more specifically to glass fiber reinforced premises cables. BACKGROUND OF THE INVENTION Fiberoptic cables are commonly used to provide electronic communication in a wide variety of indoor and outdoor communication systems. One type of indoor fiberoptic cables, typically referred to as premises, plenum, or riser cables, are comprised of buffered optical fibers and loose reinforcement polyaramid fibers contained within a fire resistant polymer jacket. The polyaramid fibers are typically coated with a coating that prevents abraiding during fiber generation. Polyaramid fibers have many important functions within premises cables. First, the polyaramid fibers provide some tensile strength during the installation process. Second, the polyaramid fibers act as a cushion and space filler to protect and suspend the loose fiberoptic fibers within the polymer jacket. Third, the polyaramid fibers prevent the adhesion of the fiberoptic fibers to the polymer jacket wall. One problem with the use of polyaramid fibers in premises cable is that the aramid fiber may add additional fuel for fire and smoke generation in certain flammable situations. This is due to the fact that aramid fibers are organic fibers. It is therefore highly desirable to provide a method for reducing or eliminating the possibility of fire or smoke generation in reinforcement fibers used in premises cables while maintaining the structural and protection attributes of the reinforcement fiber. It is also highly desirable that the reinforcement fibers used in premises cable do not ribbonize, or form bundles, that bend the fiberoptic fibers within the polymer jacket. This bending may lead to attenuation of the fiberoptic fibers, which can limit the ability of the fiber to transmit a light signal. SUMMARY OF THE INVENTION It is thus an object of the present invention to provide a method for reducing or eliminating the possibility of fire or smoke generation in reinforcement fibers used in premises cables while maintaining the structural and protection attributes of the reinforcement fibers used in indoor communication cables. The above object is accomplished by replacing the polyaramid fibers typically found in premises cables with a sized glass reinforcement fiber. As the glass fibers are inorganic, not organic, these fibers would reduce the possibility of fire or smoke generation within the premises cable. This is especially beneficial for indoor communication cables such as a premises cable that are used in commercial or residential buildings. In addition, the glass fibers provide similar structural and protection characteristics as compared with polyaramid fibers. First, the glass fibers provide some tensile strength during the installation process. Second, the glass fibers act as a cushion and space filler to protect and suspend the loose fiberoptic fibers within the polymer jacket, thereby minimizing attenuation of the fiberoptic fibers. Third, the glass fibers prevent the adhesion of the fiberoptic fibers to the polymer jacket wall. Fourth, as the glass fibers are non-ribbonized (individually sized strands, not bundle or bunched), they tend to provide uniform insulation throughout the interior of the premises cable and around the loose fiberoptic fibers. Fifth, installation of the glass fiber reinforced cable is preferred, as the polyaramid fibers do not cut as well using installation tooling. Other objects and advantages of the present invention will become apparent upon considering the following detailed description and appended claims, and upon reference to the accompanying drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 is a perspective view of a premises cable according to a preferred embodiment of the present invention; Figure 2 is a sectional view of the premises cable of Figure 1 taken along line 2-2; and Figure 3 is a logic flow diagram for forming a premises cable according to one preferred embodiment of the present invention. DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION Referring now to Figures 1 and 2, a premises cable for use in indoor communications systems is shown generally as 10. The premises cable 10 consists essentially of a plurality of randomly placed, tight buffered optical fibers 12 and a plurality of loose glass fibers 14 contained within a fire resistant polymer jacket 16. The optical fibers 12 are comprised of long, thin flexible fibers made of glass, plastic, or other transparent material that are well known in the art. Preferably, the fibers 12 are made of fused silica and are used as a pathway to transmit informational images in the form of light. The fibers 12 preferably are tight buffered and coated with a layer of acrylic coating. The fire resistant polymer jacket 16 is similarly well known in the art, and may be comprised of a wide variety of polymers that are both water and fire resistant. Preferably, the jacket 16 is formed of a thin layer of polyvinyl chloride (PVC). In alternative embodiments, the jacket 16 may be formed of a thin layer of polyethylene having a non-halogenated fire retardant such as a metal hydrate. One example of a metal hydrate that may be used in alumina trihydratc. The loose glass fibers 14 have many important functions. First, the glass fibers 14 provide some tensile strength during the installation process. Second, the glass fibers 14 act as a cushion and space filler to protect and suspend the loose fiberoptic fibers 12 within the polymer jacket 16. Third, the glass fibers prevent the adhesion of the fiberoptic fibers to the polymer jacket wall. Fourth, because glass fibers are inorganic, they does not generate smoke or fire in the presence of heat or electrical spark as does traditional organic fibers such as polyaramid fibers. As such, it acts as a fire barrier. This is especially important in that the premises cable 10 of the present invention is most likely to be used in an indoor setting, such as in a residential or commercial building. The glass fibers 14 arc preferably single end E-glass roving fibers, or Type 30® roving fibers, that can be wound in a format that is commonly used to feed cable manufacturing equipment. However, other types of glass fibers may be used as well. These include substatnially boron-free glass fibers (such Advantex® glass fibers, available from Owens Coming), S-glass or other high strength glass fibers (such as ZenTron® glass fibers, manufactured by Advanced Glassfiber Yams, LLC), E-CR glass, or any other type of glass as long as it meets the ultimate tensile strength, crush, impact, and fire resistance of the cable. The fibers 14 are protected with a sizing that has many important functions. First, the sizing allows the fibers 14 to feed through the cabling process without abraiding the glass fiber 14, commonly known as fuzzing. Also, the sizing aids in minimizing the formation of glass fibers 14 ribbons which may cause attenuation, or kinking, of the optical fibers 12, thereby preventing or limiting transmission of their respective light signals. This also allows a more uniform distribution of glass fibers 14 around the optical fibers and within the polymer jacket 16, which further helps to protect the optical fibers 12. The sizing that is used on the glass fibers 14 contains at least one film former and at least one lubricant material, preferably in a ratio of between approximately 1:1 and approximately 1:6 film former to lubricant by weight. The coating level of the sizing preferably does not exceed approximately 2.0 percent by weight of the sizing and glass fiber 14 combined, and is ideally between approximately 0.2 and 0.9 percent by weight of the of the sizing and glass fiber. This is done to limit smoking and fire that may occur, as the sizing is a potential fuel for such an occurrence. Preferably, the film former comprises a water-resistant thermoplastic or thermosetting flexible polymer. The film former functions to protect and toughen the glass fibers 14. The film former also acts as a processing aid. The film former is applied by any number of different applications that are well known in the art for adding sizing to a fiberglass roving such as dipping or spraying. The film former must be able to be emulsified, dissolved or otherwise suspendable in an aqueous medium. One such preferred film former is an epoxy-based film former. However, other polymer materials such as polyurethanes and polyethylenes are also contemplated. In the case of polyethylene, another film former such as polyvinyl pyrilidone (PVP) is typically added to prevent tackiness of the polyethylene polymer in solution. The lubricant material is typically a non-ionic material and functions to plasticize the film former. The lubricant material may consist of one material or a combination of commercially known lubricating materials known in the sizing compositions. For example, stearates and oleates of polyethylene glycol and other non-ionic petroleum-based lubricants are typically used. In addition, other additives may be added to the sizing composition to aid in processability. For example, silanes or methacryloxysilanes may be added that function to toughen the glass fiber 14 surface and provide reactive sites for bonding the glass fibers 14 to the sizing. To help hydrolyze the silane, an acid such as acetic acid may be added, wherein the pH is adjusted to around 4.5. In addition, PVP may be added in non-polyethylene-based sizings to protect and toughen the glass fibers 14, to increase glass fiber 14 strand integrity and stiffness, and/or to reduce or eliminate filament to filament bonding. An example of a preferred sizing composition for use on the glass fibers 14 in a preferred embodiment of the present invention is shown below in Table 1. To form the sizing composition as shown in Table 1, six premixes are made. In the first premix, a portion of the deionized water is mixed with the acetic acid and methacryloxysilane. In a second premix, the film former resin, here an epoxy resin, is prepared. In a third premix, a portion of the deionized number is mixed with the monooleate polyethylene glycol and the monoisostearate polyethylene glycol. While PEG 400 is listed in Table 1, of course other molecular weights of polyethylene glycol may be used, including PEG 200, 600, or 800. In a fourth premix, another portion of the deionized water is mixed with the non-ionic petroleum lubricant. In a fifth premix, a portion of the deionized water is mixed with the polyvinyl pyrilidone. In a sixth premix, a portion of the deionized water is mixed with the silane. The six premixes are then added together in order to form the sizing composition. The sizing composition as in Table 1 has a film former to lubricant ratio of strand solids of 1:4.7S. The premises cable 10 may be formed by many different methods. One preferred method is described in Figure 3. First, in Step 100, the sizing composition is applied to the glass fibers 14. The sizing may be applied using either a traditional roller applicator or through a continuous pumped head applicator. In either method, the sizing is essentially wiped onto the glass fiber as it is drawn through the applicator. Metering is done by controlling the roller speed when using a roller applicator or by pump rate when using a continuous pumped head applicator. Next, in Step 110, the sized glass fiber 14 is wound, dried and formed into a tightly wound square edged or tapered cone package on a core device such as a tube, cone, spool or bobbin. This is accomplished in one of two ways. In one method, the sized glass fiber 14 is wound onto a tightly wound square edged or tapered cone package on a core device such as a tube, cone, spool or bobbin and subsequently dried. In an alternative method, the sized glass fiber 14 is wound into a traditional forming package, dried, and later wound into a tightly wound square edged or tapered cone package on a core device such as a tube, cone, spool or bobbin. Next, in Step 120, the cabling package, or premises cable 10, is formed. This is accomplished in multiple steps. First, a first plurality of sized glass fibers 14 are applied using a linear feed or server. Next, the optical fibers 12 are applied in an S-Z stranding pattern, in which the optical fibers 12 are twisted clockwise on one rotation and counterclockwise on the next rotation. This process is repeated until a sufficient amount of optical fiber 12 is added to negate the effect of contraction or expansion of the finished premises cable 10. Next, another plurality of sized glass fibers 14 is applied using either a linear feed or a server. Finally, the polymer jacket 16 is applied using a tube extrusion process to form the premises cable 10. The present invention offers an alternative reinforcement material for use in indoor communication cables such as a premises cable. These new premises cables having glass finer reinforcement are ideally suited for use in commercial or residential buildings. As glass fibers are inorganic, unlike polyaramid fibers, these fibers would reduce the possibility of fire or smoke generation within the premises cable. In addition, the glass fibers provide similar structural and protection characteristics as compared with polyaramid fibers. Also, the glass fibers provide some tensile strength during the installation process. Further, the glass fibers act as a cushion and space filler to protect and suspend the loose fiberoptic fibers within the polymer jacket. Finally, the glass fibers prevent the adhesion of the fiberoptic fibers to the polymer jacket wall. While the invention has been described in terms of preferred embodiments, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. WE CLAIM : 1. A premises cable (10) comprising: a fire resistant polymer jacket (16) having an inner wall; and a plurality of optical fibres (12) and a plurality of loose, non-ribbonised inorganic fibres (14), both received within said jacket (16), wherein each of said inorganic fibres (14) is encased within a sizing composition that comprises at least one film former and at least one lubricant material; and said inorganic fibres (14) are distributed uniform!) throughout the interior of the jacket (16) about each of said plurality of optical fibres (12) so as to fill the space in said interior and to space said optical fibres (12) from one another and from the inner wall of the jacket (16), the arrangement being such that said plurality of optical fibres (12) are suspended, cushioned and protected by said plurality of inorganic fibres (14) within said fire resistant polymer jacket (16). 2. A premises cable as claimed in Claim I. wherein said sizing composition comprises between 0.1 and 2.0 percent of the strand weight of said plurality of inorganic fibres. 3. A premises cable as claimed in Claim 1 or Claim 2, wherein a ratio of said at least one film former to said at least one lubricant is between 1: 1 and 1: 6 of strand solids deposited on said plurality of inorganic fibres. 4. A premises cable as claimed in any preceding claim, wherein said fire resistant polymer jacket is selected from the group consisting of a polyvinyl chloride jacket and a polyethylene jacket having a non-halogenated fire retardant additive. 5. A premises cable as claimed in any preceding claim, wherein said plurality of inorganic fibres is selected from the group consisting of a plurality of E-glass fibres, a plurality of E-CR glass fibres, a plurality of substantially boron-free glass fibres, and a plurality of S-glass glass fibres. 6. A premises cable as claimed in any preceding claim, w herein said at least one film former comprises an epoxy resin. 7. A premises cable as claimed in any preceding claim, wherein said at least one film former comprises a polyvinyl pyrrolidone resin. 8. A premises cable according to any preceding claim, wherein said at least one lubricant material is selected from the group consisting of a non-ionic petroleum lubricant, a monooleate polyethylene glycol, a monoisostearatc polyethylene glycol, and combinations thereof. 9. A premises cable according to any preceding claim, wherein said sizing composition further comprises at least one additive material. 10. A premises cable according to Claim 9, wherein said at least one additive material is selected from the group consisting of a methacryloxysilane material and a silane material. 11. A method of forming a premises cable (10) according to any of Claims I to 10, the method comprising the steps of: preparing a sizing composition, said sizing composition comprising at least one film former and at least one lubricant material; applying said sizing composition to a plurality of loose inorganic fibres (14) using an applicator to form a plurality of non-ribbonised inorganic fibres; wrapping a first amount of said plurality of loose inorganic fibres (14) on a mounting apparatus; introducing a plurality of optical fibres (12) around said first amount of plurality of inorganic fibres in an s-z stranding pattern in such a way that said optical fibres (12) are spaced from one another; wrapping a second amount of said loose inorganic fibres around said plurality of optical fibres; and applying a fire resistant polymer jacket (16) around said second amount of the inorganic fibres to form a premises cable, said jacket having an inner wall; the arrangement being such that said plurality of loose inorganic fibres (14) are received and distributed uniformly throughout the interior of said jacket (16) about each of said plurality of optical fibres (12) so as to fill the space in said interior and to space said optical fibres (12) from one another and from the inner wall of the jacket (16), whereby said plurality of optical fibres (12) are suspended, cushioned and protected by said plurality of inorganic fibres (14) within said fire resistant polymer jacket (16). 12. A method according to Claim 11, wherein the step of applying said sizing composition to a plurality of inorganic fibres (14) using an applicator comprises using a roller applicator or a continuous pump head applicator to apply said sizing composition to said plurality of inorganic fibres. 13. A method according to Claim II or 12, wherein the step of wrapping a first amount of said plurality of inorganic fibres on a mounting apparatus comprises the steps of wrapping a first amount of said plurality of inorganic fibres on a server or a linear feeder. 14. A method according to any of Claims 11 to 13; wherein sizing composition comprises at least one film former and at least one lubricant material, wherein a ratio of said at least one film former to said at least one lubricant material is between 1:1 and 1:6 of strand solids deposited on said plurality of inorganic fibres. 15. A method according to any of Claims 11 to 14, wherein said sizing composition comprises between 0.1 and 2.0 percent of the strand weight of said plurality of inorganic fibres. It is thus an object of the present invention to provide a method for reducing or eliminating the possibility of fire or smoke generation in reinforcement fibers used in premises cables while maintaining the structural and protection attributes of the reinforcement fibers used in indoor communication cables. The above object is accomplished by replacing the polyaramid fibers typically found in premises cables with a sized glass reinforcement fiber. As the glass fibers are inorganic, not organic, these fibers would reduce the possibility of fire or smoke generation within the premises cable. This is especially beneficial for indoor communication cables such as a premises cable that are used in commercial or residential buildings.

Documents:

1401-kolnp-2003-abstract.pdf

1401-kolnp-2003-assignment 1.1.pdf

1401-kolnp-2003-assignment.pdf

1401-kolnp-2003-claims.pdf

1401-kolnp-2003-correspondence 1.1.pdf

1401-kolnp-2003-correspondence.pdf

1401-kolnp-2003-description (complete).pdf

1401-kolnp-2003-drawings.pdf

1401-kolnp-2003-examination report 1.1.pdf

1401-kolnp-2003-examination report.pdf

1401-kolnp-2003-form 1.1.pdf

1401-kolnp-2003-form 1.pdf

1401-kolnp-2003-form 18.1.pdf

1401-kolnp-2003-form 18.pdf

1401-kolnp-2003-form 2.1.pdf

1401-kolnp-2003-form 2.pdf

1401-kolnp-2003-form 26.1.pdf

1401-kolnp-2003-form 3.1.pdf

1401-kolnp-2003-form 3.2.pdf

1401-kolnp-2003-form 3.pdf

1401-kolnp-2003-form 5.1.pdf

1401-kolnp-2003-form 5.pdf

1401-kolnp-2003-form 6.1.pdf

1401-kolnp-2003-form 6.pdf

1401-kolnp-2003-granted-abstract 1.1.pdf

1401-kolnp-2003-granted-claims 1.1.pdf

1401-kolnp-2003-granted-description (complete) 1.1.pdf

1401-kolnp-2003-granted-drawings 1.1.pdf

1401-kolnp-2003-granted-form 1.1.pdf

1401-kolnp-2003-granted-form 2.1.pdf

1401-kolnp-2003-granted-specification 1.1.pdf

1401-kolnp-2003-others1.1.pdf

1401-kolnp-2003-pa.pdf

1401-kolnp-2003-reply to examination report 1.1.pdf

1401-kolnp-2003-reply to examination report.pdf

1401-kolnp-2003-specification.pdf