DE102005052045A1 - Optical cable, has transmission element and optical fiber enclosed by cylindrical cable wall - Google Patents

Abstract

An optical cable has at least one optical transmission element (10) comprising at least one optical fiber (11), a cable wall (300) enclosing the optical transmission element (10), and in which the cable wall material contains a polymer and dry water-glass. An independent claim is given for a method for fabricating an optical cable.

Description

The The invention relates to an optical cable and a method of manufacturing an optical cable in which an optical transmission element of a Cable sheath is surrounded.

One Optical cable generally has at least one optical transmission element on, which contains one or more optical fibers. At a optical cables with loose tubes a plurality of optical fibers are arranged as a bundle, by a tubular cover are surrounded. Inside a cable core of the optical cable there are several such loose tubes. With a solid-core optical cable, the cable core becomes off formed of a plurality of optical waveguides, each of a fixed cover are surrounded. The cable core will generally work on both types of cable protected by a cable sheath.

Either for the Cable sheath as well for the tubular ones Covers the loose tubes and the protective covers The hard cores use thermoplastic materials. The Fire behavior of such thermoplastic materials, in particular the sheath materials of optical cables used as indoor cables in buildings used, is subject to high and complex testing requirements. These are based on the fire hazard, the development of fire, the fire expansion and the combustion products and residues resulting from the fire in severe Standards and measuring methods.

Around to improve the fire behavior of thermoplastic materials In general, mineral flame retardants are used. The thermoplastic materials are doing with mineral flame retardant fillers enriched. Aluminum hydroxide and magnesium hydroxide provide by far the largest share on such mineral flame-retardant fillers. The above Minerals belong to the active flame retardants. In a fire, the aluminum hydroxide or the magnesium hydroxide releases water vapor which dilutes the fumes. By the enthalpy of vaporization is deprived of heat to the system, causing the fire is reduced.

Next Aluminum hydroxide and magnesium hydroxide are also used in special cases so-called Huntite, such as magnesium carbonates or calcium carbonates, and hydromagnesites, such as magnesium hydroxycarbonates. Such mineral fillers are non-flammable and serve the thermoplastic combustible To dilute materials.

Around when using mineral fillers a flame retardant Effect is for this fillers a very high proportion of filler necessary. For example, to meet the high fire requirements Mass proportions from 50% to 60% filler be present in the thermoplastic materials. The higher the Mass fraction of the filler in a polymer material, the harder the thermoplastic ones become Materials. When using highly filled polymers, the mechanical properties of the polymer material, such as melt index, Impact resistance, Elongation at break and general processability negatively affected.

The The object of the present invention is to specify an optical cable in which a shell material a shell has good processing and fire retardant properties. A Another object of the present invention is a method to provide for the production of an optical cable, in which a shell material a shell has good processing and fire retardant properties.

The The optical cable problem is solved by an optical cable with at least one optical transmission element, which comprises at least one optical waveguide, and with a shell, the the optical transmission element surrounds. The case has a shell material containing a polymer and a dry water glass.

According to one Development of the optical cable is a mass fraction of the dry water glass on a total mass of the wrapping material more than 5%. According to another feature of the optical cable is the mass fraction of the dry water glass to the total mass of the shell material less than 70 %. Preferably the mass fraction of the dry water glass on the total mass of the shell material between 20% and 40%.

In one embodiment of the optical cable, it is provided that the dry water glass contains sodium silicate. The sodium silicate may have a molar mass ratio of SiO ₂ : Na ₂ O of 3.0: 3.2. The sodium silicate may also have a molar mass ratio of SiO ₂ : Na ₂ O of 1.9: 2.1.

According to another embodiment of the optical cable, the dry water glass contains potassium silicate. The potassium silicate preferably has a molar mass ratio of SiO ₂ : K ₂ O of 3.0: 3.3.

A refinement of the optical cable provides that the polymer is polyethylene, polypropy len, polybutylene terephthalate, polycarbonate, acrylic-butadiene-styrene copolymer, polyamide, polyvinyl chloride, polyurethane, ethylene tetrafluoroethylene or elastomers.

According to one another embodiment contains the wrapping material a mineral. The shell material preferably contains Aluminum hydroxide or magnesium hydroxide. The wrapping material may also contain Huntite. Preferably contains the wrapping material Magnesium carbonate or calcium carbonate. Furthermore, the shell material Hydromagnesites included. As another possibility, the shell material magnesium hydroxycarbonate contain.

The Cover of the optical cable is preferably as a cable sheath of the optical Cable is formed.

According to one Further development is the at least one optical transmission element as a loose tube formed in which several optical fibers from another Shell surrounded are the shell material contains. The further shell the loose tube is surrounded by the cable sheath.

According to one another embodiment of the optical cable is the at least an optical transmission element formed as a solid core, in which exactly one optical fiber from a protective cover surrounded, which is the wrapping material contains. The protective cover the rigid core is surrounded by the cable sheath.

The at least one optical transmission element can also be designed as a fiber ribbon be, which comprises several Lichtwel waveguide. The fiber ribbon is in this embodiment of surrounded by the cable sheath.

in the Following is a method of making an optical cable specified. The method provides for providing a mixture, containing a polymer and a dry water glass. This mixture is heated. Furthermore, at least one optical transmission element is provided, which contains at least one optical waveguide. The heated mixture is at least one optical transmission element extruded to form a cable sheath.

at a further embodiment the process is intended that the mixture by mixing a Powder of the dry water glass is provided with the polymer.

A another possibility to provide the mixture is a carrier mixture by Predispersing a powder of dry water glass with a to provide further polymer, wherein the further polymer is less viscous than the polymer is and the carrier mixture to mix with the polymer.

at an embodiment of the method a mass fraction of the dry water glass in a total mass of Mixture between 20% and 40%.

According to one another embodiment of the method is provided that as dry water glass sodium silicate or potassium silicate is used.

The sodium silicate with a molar mass ratio of SiO ₂ : Na ₂ O of 3.0: 3.2 or SiO ₂ : Na ₂ O of 1.9: 2.1 is preferably used in the process according to the invention. Potassium silicate is preferably used with a molar mass ratio of SiO ₂ : K ₂ O of 3.0: 3.3.

at In one embodiment of the method, the at least one optical transmission element in Shape of a loose tube provided. For this purpose, several optical fibers become one bunch arranged. The heated Mixture is applied around the multiple optical fibers to form a cover the loose tube extruded.

at In a further embodiment of the method, the at least an optical transmission element provided in the form of a tight vein. This is an optical fiber provided to the heated Mixture extruded to form a protective cover of the hard core becomes.

A another embodiment of the method provides that providing the at least one optical transmission element by arranging a plurality of optical fibers into a fiber ribbon.

The Invention will be described below with reference to figures, the embodiments of the present invention, explained in more detail.

It demonstrate:

1 an embodiment of a layer-stranded optical cable with loose tubes,

2 an embodiment of a optical cable with hard cores,

3 an embodiment of an optical cable used as a connection cable

4 an embodiment of an optical cable as a ribbon cable,

5 a device for producing a optical cable,

6 an apparatus for producing a mixture of a shell material.

According to the invention, it is proposed to add polymers, which are generally used as materials for a cable jacket of an optical cable, to so-called dry water glasses. The 1 to 4 show cable constructions in which especially for the cable sheaths thermoplastic materials can be used with blended dry water glasses.

1 shows a layered optical cable with loose tubes. A cable soul 100 has a strain relief element 1 on to the multiple optical transmission elements 10 are arranged. The optical transmission elements 10 are designed as loose tubes and include multiple optical fibers 11 that of a tubular protective cover 12 are surrounded. The cable core 100 is from a cable sheath 300 protected.

According to the invention in particular contains the cable sheath 300 a polymer in which dry water glasses are mixed. Such a flame-retardant mixture of a polymer and a dry water glass can also be used for the casings 12 the loose tubes are used. The polymer used may be one of the following materials, such as PE (polyethylene), PP (polypropylene), PBT (polybutylene terephthalate), PC (polycarbonate), ABS (acyl-butadiene-styrene copolymer), PA (polyamide), PVC (polyvinyl chloride) , PU (polyurethane), ETFE (ethylene tetrafluoroethylene) and elastomers, or a combination thereof. As dry water glasses, sodium silicates or potassium silicates are used. The sodium silicates preferably have a molar mass ratio of SiO ₂ : Na ₂ O of 3.0 3.2 or SiO ₂ : Na ₂ O of 1.9: 2.1. Potassium silicates are preferably used with a molar mass ratio of SiO ₂ K ₂ O of 3.0: 3.3. Cupanone type dry water glasses such as Cupanon TR, Cupanon DI and Cupanon POT are available, for example, from Silinwerk van Baerle & Co. GmbH, Woellner-Werke GmbH & Co. KG, Cognis Deutschland GmbH & Co. KG or PQ Germany GmbH.

The mentioned dry water glasses can easily find use in thermoplastic polymers. The mass fraction The mentioned silicates can vary between 5% and 70 depending on the application %, it is but preferably between 20 and 40%. When using Dry water glasses remain in a polymer with the above indicated proportions by weight the mechanical properties of the polymer into which the dry water glasses are mixed be preserved as far as possible.

Of Furthermore, such a material mixture is particularly fire-retardant Properties on. In case of fire in mixtures of this kind are the Glass components at temperatures above 600 degrees Celsius soft and the salts increase their Surface. The plastic components on the surface burn partially and begin with the glass layer a closed carbide layer or Thermal protection layer form. There are thus inorganic ceramic products that are no longer flammable. The thermal Protective layer dissolves only at about 900 degrees Celsius by a flow of the Glass layer gradually on. However, it is prevented by the carbide layer from flowing away.

The causes flame retardant according to the invention thus a stable charring, encrustation or glazing of the burnt material. This will cause an up or down Chipping the forming protective layer avoided. Furthermore are used in the decomposition of flame retardant materials that the mentioned dry water glasses contained, the combustion process of the plastic considerable Heat removed. The thermoplastic material is characterized by a fast thermal Protected degradation. The formation of combustible decomposition products is inhibited and the emerging water vapor displaced the oxygen and thus acts as a protective gas. Thus, the fire spread be reduced.

Next the use of thermoplastic materials mixed with Dry water glasses let the dry water glasses also with conventional Flame retardants, for example with mineral flame retardants, combine.

2 shows an optical cable, in which the cable core 100 several optical transmission elements 20 includes, which are designed as hard cores. An optical fiber 21 is from a protective cover 22 surround. The cable core 100 is from a cable sheath 300 protected. The inside of the cable sheath is by a swelling fleece 200 disconnected from the cable core. When water penetrates into the cable, the nonwoven material swells and seals the filling compound-free cable core. Furthermore, the nonwoven material keeps the resulting high temperatures of the cable core when extruding the cable sheath. In addition to the use of the mixture of a polymer according to the invention and a dry water glass for the cable sheath, such a mixture can also be used for the protective sheath 21 to use the solid lines. The mixture can be in The above embodiments are used.

3 shows two cable ends of a connection cable. The two cable ends are via a web connection 500 connected with each other. Each of the two cable ends contains a sturdy core inside 20 that is an optical fiber 21 and a protective cover 22 includes. Between the solid line 20 and a cable sheath 300 there is a strain relief 400 containing, for example, aramid. In particular, the cable sheath 300 but also the protective cover 22 the solid core contain the inventive fire retardant mixture of a polymer and a dry water glass, in the above-mentioned embodiments.

4 shows an optical cable, which is designed as a ribbon cable. optical fiber 31 are arranged side by side in a row and by a strain relief element 400 surround. To the strain relief element is a cable sheath 300 extruded. In this arrangement, only the cable sheath comprises the mixture according to the invention of a polymer and a dry water glass which can be used in the abovementioned embodiments.

Next Dry water glasses still have the good fire protection properties more benefits. This allows the dry water glasses to be light in the usual Mix in plastics. They provide a cost-effective material with a high utility value. Furthermore, the dry water glasses as fillers for any use thermoplastic materials. They are environmentally friendly and recyclable and above also not corrosive.

5 shows an arrangement for producing the optical cable according to the invention with a bundled or rigid wire. For the sake of simplicity, in the 5 only the two extruders E1 and E2 shown, with which a protective sheath is extruded around the optical waveguide or a cable sheath is extruded around the optical transmission elements.

One container B1 and a container B2 are connected to an extruder E1 and an extruder E2. The two containers contain a mixture of a polymer P1 and a dry water glass T. As dry water glasses Sodium or potassium silicates are used, the polymer as Be mixed with powder. The mixing ratio is chosen so that the mass fraction of said silicates between 5% and 70%, preferably however, between 20% and 40% of the total mass of the mixture G1 is. The mixture G1 is heated in both containers, so that in the containers B1 and B2 forms a polymer melt.

The extruder E1 is an optical waveguide for producing a loose tube 11 or for producing a solid wire an optical waveguide 21 fed. When producing a loose tube, several of the optical fibers are used 11 arranged in a bundle. Within the extruder E1, a shell having the mixture G1 is extruded around the optical fiber bundle. When making a tightrope in the extruder E1 to the hard core 21 extruded a protective sheath containing the mixture G1.

The loose tube 10 or the solid line 20 are then fed to the extruder E2. In the extruder E2, the cable sheath is extruded around the buffer tube or around the rigid core. As jacket material, the mixture G1 present in the container B2 is used. The mixture G1 in turn represents a mixture of a polymer with a dry water glass, wherein the proportion of the dry water glass in the total mass of the mixture is more than 5% and less than 70%. Preferably, the mass fraction of the dry water glass in the total mass of the mixture G1 is between 20% and 40%.

6 shows a further possibility for producing a mixture G2, which is used in particular as a sheath material but also as a sheath material for the sheath of a loose tube or as a sheath material for the protective cover of a hard core. A container B2 is connected to a container B3. In the container B2, the dry water glass T is predispersed with a polymer P2. The polymer P2 thus serves as a carrier material (batch). The polymer P2 is very low viscosity compared to the polymer P1, so that the sodium or potassium silicates of the dry water glass T distribute well in the mixture G2. The mixture G2 is then added to the actual shell or shell polymer P1. The mass fraction of the sodium or potassium silicates in the total mass of the mixture is between 5% and 70% and preferably between 20% and 40%.

1

strain relief

10

Loose Tube

11

optical fiber

12

buffer tube

20

Tight buffer

21

optical fiber

22

cover

30

slivers

31

optical fiber

100

cable core

200

swelling tape

300

cable sheath

400

strain relief

500

web connection

B

container

e

extruder

G

mixture

P

polymer

T

Dry water glass

Claims (30)

Optical cable - with at least one optical transmission element ( 10 . 20 . 30 ), the at least one optical waveguide ( 11 . 21 . 31 ), - with a shell ( 300 ), the optical transmission element ( 10 . 20 . 30 ), - in which the envelope ( 300 ) comprises a shell material containing a polymer and a dry water glass. An optical cable according to claim 1, wherein a mass fraction of the dry water glass to a total mass of the wrapping material more than 5%. Optical cable according to one of claims 1 or 2, wherein the mass fraction of dry water glass to the total mass of the wrapping material less than 70%. Optical cable according to one of claims 1 to 3, in which the mass fraction of dry water glass to the total mass of the wrapping material between 20% and 40%. Optical cable according to one of claims 1 to 4, in which the dry water glass contains sodium silicate. An optical cable according to claim 5, wherein the sodium silicate has a molar mass ratio of SiO ₂ Na ₂ O of 3.0: 3.2. An optical cable according to claim 5, wherein the sodium silicate has a molar mass ratio of SiO ₂ Na ₂ O of 1.9: 2.1. Optical cable according to one of claims 1 to 4, in which the dry water glass contains potassium silicate. An optical cable according to claim 8, wherein the potassium silicate has a molar mass ratio of SiO ₂ K ₂ O of 3.0: 3.3. Optical cable according to one of claims 1 to 9, wherein the polymer is polyethylene, polypropylene, polybutylene terephthalate, Polycarbonate, acrylic-butadiene-styrene copolymer, polyamide, polyvinyl chloride, polyurethane, Contains ethylene tetrafluoroethylene or elastomers. Optical cable according to one of claims 1 to 10, in which the shell material contains a mineral. Optical cable according to one of claims 1 to 11, in which the shell material Contains aluminum hydroxide or magnesium hydroxide. Optical cable according to one of claims 1 to 10, in which the shell material Huntite contains. An optical cable according to claim 13, wherein the sheath material Magnesium carbonate or calcium carbonate contains. Optical cable according to one of claims 1 to 14, in which the shell material Hydromagnesite contains. Optical cable according to one of claims 1 to 15, in which the shell material Magnesiumhydroxycarbonat contains. Optical cable according to one of Claims 1 to 16, in which the sheath is used as a cable sheath ( 300 ) of the optical cable is formed. Optical cable according to one of Claims 1 to 17, in which the at least one optical transmission element is in the form of a loose tube ( 10 ) is formed, in which a plurality of optical waveguides ( 11 ) of another envelope ( 12 ), which contains the shell material, - in which the further shell ( 12 ) of the loose tube from the cable sheath ( 300 ) is surrounded. Optical cable according to one of Claims 1 to 17, - in which the at least one optical transmission element is used as a solid core ( 20 ) is formed, in which exactly one optical waveguide ( 21 ) of a protective cover ( 22 ), which contains the wrapping material, - in which the protective cover ( 22 ) the hard core ( 20 ) of the cable sheath ( 300 ) is surrounded. Optical cable according to one of Claims 1 to 17, - in which the at least one optical transmission element is designed as a fiber ribbon ( 30 ) is formed, the plurality of optical fibers ( 31 ), in which the fiber ribbon ( 30 ) of the cable sheath ( 300 ) is surrounded. A process for producing an optical cable, comprising the steps of: providing a mixture (G1, G2) containing a polymer (P1) and a dry water glass (T), heating the mixture (G1, G2), Providing at least one optical transmission element ( 10 . 20 . 30 ), the at least one optical waveguide ( 11 . 21 . 31 ), - extruding the heated mixture (G1, G2) around the at least one optical transmission element ( 10 . 20 . 30 ) for forming a cable sheath ( 300 ). The method of claim 21, comprising the following Steps: Providing the mixture (G1) by mixing a Powder of dry water glass (T) with the polymer (P1). The method of claim 21, wherein providing of the mixture (G2) comprises the following steps: - Provide a carrier mixture (G3) by predispersing a powder of the dry water glass (T) with a further polymer (P2), wherein the further polymer is less viscous when the polymer is (P1), - Mix of the carrier mixture (G3) with the polymer (P1). Method according to one of claims 22 or 23, wherein a Mass fraction of the dry water glass to a total mass of the mixture (G1, G2) is between 20% and 40%. Method according to one of claims 21 to 24, in which as Dry water glass sodium silicate or potassium silicate is used. A process according to claim 25, wherein the sodium silicate having a molar mass ratio of SiO ₂ : Na ₂ O of 3.0: 3.2 or SiO ₂ : Na ₂ O of 1.9: 2.1 is used. The method of claim 25, wherein potassium silicate having a molar mass ratio of SiO ₂ K ₂ O of 3.0: 3.3 is used. Method according to one of claims 21 to 27, comprising providing the at least one optical transmission element in the form of a loose tube ( 10 ) by performing the following steps: arranging a plurality of optical fibers ( 11 ) into a bundle, - extruding the heated mixture (G1, G2) around the plurality of optical waveguides ( 11 ) for forming a protective cover ( 12 ) of the loose tube. Method according to one of claims 21 to 27, comprising providing the at least one optical transmission element in the form of a solid core ( 20 ) by performing the following steps: - providing an optical waveguide ( 21 ), - extruding the heated mixture (G1, G2) around the optical waveguide ( 21 ) for forming a protective cover ( 22 ) the hard core. Method according to one of claims 21 to 27, comprising providing the at least one optical transmission element by arranging a plurality of optical waveguides ( 31 ) to a fiber ribbon ( 30 ).