JPS5879202A - Waterproof mixture for optical fiber cable - Google Patents

Abstract

PURPOSE:To prevent the transmission loss of optical fibers by blending naphthene or paraffin oil with low mol.wt. polyethylene or petroleum wax to prepare a waterproof mixture to be filled into a cable contg. the optical fibers at ordinary temp. CONSTITUTION:When optial fibers are bundled and set in a cable, a hollow part is left. By filling a waterproof mixture into the hollow part, the fibers are made waterproof and protected. The mixture is a greasy mixture which is viscous at ordinary temp. and is prepared by mixing 100pts.wt. of naphthene or paraffin oil with 5-25pts. low mol.wt. polyethylene or petroleum wax, 10-50pts. inorg. filler such as clay and 0.1-1pt. antioxidant. The grease is filled into the hollow part at ordinary temp. without applying a strain to the optical fibers in the cable. The mixture is waterproof and flexible, maintains the mechanical strength of the optical fibers and prevents an increase in the transmission loss.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to waterproofing admixtures for use in waterproof fiber optic cables.

Waterproof optical fiber cables completely fill the spaces between the optical fibers in the cable and between the units that bundle them with a waterproofing compound to prevent water from entering from the outside and reduce the mechanical strength of the fibers due to water absorption. In addition to suppressing the decrease in transmission loss and increase in transmission loss, it also provides inter-fiber and unit 6 properties and gives the cable more flexibility.
The mixture used for this is a petrolatum-based mixture that is used for general Shelly cables, and in Japan, a polybutene-based mixture is used.

(Trollatum-based mixtures are made by adding low-molecular-weight polyethylene, petroleum wax, and antioxidants to 4-trolatam after petroleum refinement, and polybutene-based mixtures are made by adding petroleum wax, antioxidants, etc. to polybutene. These mixtures are heated to a fluid state and injected into the cable sheath, but when these mixtures are used as mixtures for optical fiber cables, the temperature during injection into the cable is Heating the mixture to about 80 to 100°C causes strain in the fiber, increasing transmission loss;
When the injected mixture cools and solidifies, the volume shrinks, creating gaps in the mixture that allow water to penetrate, resulting in insufficient waterproofing.Furthermore, these mixtures are sticky, making it difficult to connect cables. There were drawbacks such as the fact that it took a lot of time to wipe and comb.

The present invention is a mixture for waterproof optical fiber cables consisting of naphthene:%C, paraffinic oil, low molecular weight polyethylene or petroleum wax, an inorganic filler, and an antioxidant added as necessary. To provide a waterproofing mixture with excellent performance, which can be injected without heating, prevents water permeability due to shrinkage, and is easy to wipe off during connection.

That is, the mixture for waterproof optical fiber cables according to the present invention is obtained by mixing the above-mentioned components, and is in the form of a viscous grease at room temperature, and can be easily injected into cables at room temperature. . Therefore, no distortion is applied to the fibers in the cable, and no increase in transmission loss due to distortion occurs. In addition, since the injection into the cable is carried out at room temperature, there is no volumetric shrinkage due to cooling and solidification of the admixture.Therefore, there are no gaps in the admixture within the cable, and the waterproof properties are not impaired. Nor.

In addition, when connecting waterproof cables, the waterproof mixture adhering to the connection parts and terminal parts can be easily wiped off and removed because the mixture of the present invention is based on oil. The work is sieved.

1. On the other hand, since the mixture of the present invention has a high dropping point by adding low-i polyethylene or petroleum wax and an inorganic filler, the mixture does not drip down from the end of the cable.

To explain the mixture of the present invention in more detail, the oil in the mixture is used as a base binder, but the naphthenic or paraffinic mineral oil has good electrical properties and is a connector material often used for cable connections. It is less likely to cause stress cracks even with polycarbonate, and is low in cost and friction. On the other hand, aromatic mineral oils are not preferred because they tend to cause stress cracks in polycargenate and have poor electrical properties.

In addition, low molecular weight polyethylene or petroleum wax is added to adjust the viscosity of the mixture and increase the dropping point. There are microcrystalline waxes, etc.

Additionally, inorganic fillers are added to the mixture for the purpose of controlling viscosity and increasing the dropping point, which is not sufficient when adding low molecular weight polyethylene or petroleum wax alone.Specifically, inorganic fillers include clay, calcium carbonate, silica, and Magnesium, talc, etc.

Further, the antioxidant acts to prevent oxidation of the mixture. For example, as a phenol-based stabilizer, tetrakis[methylene-3(3,5t-butyl-4-hydroxyphenyl)gropione-?] )/tan...Product name: Irganoss 1010 or 4,4'-thio-bis(3-methyl-6-t-butylphenol)...Product name: Santo-Nox R or 2,6-di-t-butyl-p -Cresol・
...Product names such as BHT may be mentioned, but most of them are defined by this.

The preferred composition of the mixture of the present invention is as follows.

Oil 100 parts by weight Low molecular weight polyethylene or petroleum wax 5-25
〃・Inorganic filling side 10 to 5σ I antioxidant 0.1 to 1 〃In the mixture of the present invention・Low molecular weight polyester per 100 parts by weight of oil)
If the ethylene or petroleum wax is less than 5 parts by weight, the wax will lack viscosity and will become drippy at room temperature, which is undesirable. If it exceeds 25 parts by weight, the wax will not have fluidity at room temperature, which is undesirable.

If the amount exceeds 1 part by weight, the room temperature fluidity will be inhibited, which is not preferable.

Next, if we compare the mixture of the present invention and a conventional waterproof mixture, we will see the following.

JP-A-58-79202 (3) Umbrella 1: JIB K 2524% m constant temperature 2
5℃ Umbrella 2: JIB K 2561 Monkey 3-4: JIB C2101, IM
klx agent: JIB Czxoi Junior high school 6: IIPOM-142C Umbrella 7: RIA Pie-39 Patent applicant Nippon Telegraph and Telephone Public Corporation Fujikura, Dens Corporation agent Mamoru Takeuchi

Claims (1)

[Claims] 1. A mixture for waterproof optical fiber kesol, characterized in that it is made by adding naphthenic or graphene oil, low molecular weight polyethylene or petroleum wax, an inorganic filler and, if necessary, an antioxidant.