JPH054764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a water stop agent for optical cables and power cables. More specifically, it relates to a water-stopping agent that prevents salt water from moving inside the sheath and deteriorating the cable and various devices when highly concentrated salt water such as seawater intrudes into the sheath of an optical/power cable. be. (Prior art) When the sheath of an optical/power cable is damaged and water infiltrates into the sheath, there is a problem that the water quickly moves inside the sheath and deteriorates the optical fiber, power line, or various devices. . In order to solve this problem, a method has been proposed in which the inside of the sheath is filled with a water-absorbing resin. Examples of such water-absorbent resins include conventionally crosslinked sodium polyacrylates, neutralized starch-acrylic acid graft polymers, saponified vinyl acetate-acrylic acid ester copolymers, and isobutylene-acrylate copolymers.
Neutralized products of maleic anhydride copolymer crosslinked products have been used. However, these conventional water-absorbing resins irreversibly reduce their water-absorbing ability when they come into contact with polyvalent metal ions such as calcium and magnesium, so if seawater enters the sheath or low concentrations of calcium ions from groundwater etc. There was a problem in that even if the water contained therein penetrated for a long period of time, the water stopping effect would no longer be exhibited. (Problems to be Solved by the Invention) The present invention solves the above problems. Therefore, the object of the present invention is to provide a cable with excellent salt resistance that does not reduce its water absorption capacity even when it comes into contact with highly concentrated salt water that has entered the sheath of an optical/power cable, and exhibits a stable water-stopping effect over a long period of time. The purpose of the present invention is to provide water-stopping agents for optical and power cables. (Means and effects for solving the problems) The present invention provides 0.5mg of sulfonic acid group or its salt.
equivalent/g or more, and contains dissociable groups of 1.0 mg equivalent/g.
The object of the present invention is to provide a water stop agent for optical/power cables comprising a crosslinked polymer containing at least 100 g. The sulfonic acid groups or their salts contained in the crosslinked polymer used in the present invention include sulfonic acid groups and metal salts of sulfonic acid groups such as sodium salts, potassium salts, calcium salts, magnesium salts, and zinc salts; Examples include ammonium salts of sulfonic acid groups and organic amine salts of sulfonic acid groups. Furthermore, the dissociative groups contained in the crosslinked polymer used in the present invention include anionic dissociative groups such as sulfonic acid groups, carboxylic acid groups and their metal salts, ammonium salts, and organic amine salts, as well as amines and quaternary Includes cationic dissociative groups such as ammonium salts. The crosslinked polymer used in the present invention must contain 0.5 mg equivalent/g or more of sulfonic acid groups or their salts and 1.0 mg equivalent/g or more of dissociable groups. When the amount of dissociable groups is less than 1.0 mg equivalent/g, the water-blocking effect will not appear because the water-absorbing capacity of the crosslinked polymer will be small. Sulfonic acid group or its salt is 0.5
If the amount is less than mg equivalent/g, the crosslinked polymer becomes susceptible to the effects of polyvalent metal salts, making it impossible to obtain a stable water-stopping effect over a long period of time. The crosslinked polymer used in the present invention preferably has a water absorption capacity of 5 times or more of its own weight for deionized water. If it is less than 5 times, it will be difficult to maintain a sufficient water-stopping effect over a long period of time. The polymer crosslinking pair effective as a water stopper for optical/power cables of the present invention can be obtained, for example, by a method in which a sulfonic acid group-containing unsaturated monomer (A) is polymerized in the presence of a crosslinking agent (C) if necessary. , unsaturated monomer containing sulfonic acid group
A method of copolymerizing (A) and other polymerizable monomers (B) in the presence of a crosslinking agent (C) if necessary; A method of sulfonating the polymer crosslinked product obtained by polymerization with a sulfonating agent such as sulfuric acid, sulfuric anhydride, 1,3-propanesultone, 1,4-butasultone,
It can be produced by a method in which a linear polymer obtained by polymerizing the polymerizable monomer (B) is reacted with a crosslinking agent (C) and simultaneously sulfonated with a sulfonating agent. Examples of the sulfonic acid group-containing unsaturated monomer (A) that can be used in producing the crosslinked polymer in the present invention include vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, 2-sulfoethyl (meth)acrylate, 3-sulfopropyl (meth)acrylate, 1-sulfopropan-2-yl (meth) Unsaturated sulfonic acids such as acrylate, 2-sulfopropyl (meth)acrylate, 1-sulfobutan-2-yl (meth)acrylate, 2-sulfobutyl (meth)acrylate, 3-sulfobutan-2-yl (meth)acrylate; Examples include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium and magnesium, other metal salts such as zinc, ammonium salts, and organic amine salts, and one or two types from these. The above can be used. Other polymerizable monomers (B) that can be used in the present invention include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and citraconic acid; Carboxy group-containing unsaturated monomers such as alkali metal salts, alkaline earth metal salts, ammonium salts or organic amine salts; (meth)acrylamide, (meth)acrylonitrile, vinyl acetate,
Water-soluble unsaturated monomers such as N,N-dimethylaminoethyl (meth)acrylate, 2-(methacryloyloxyethyl)trimethylammonium chloride; hydroxyethyl (meth)acrylate,
Hydroxypropyl (meth)acrylate, polyethylene glycol mono(meth)acrylate,
Polypropylene glycol mono(meth)acrylate, polybutylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, methoxypolypropylene glycol mono(meth)acrylate, methoxypolybutylene glycol mono(meth)acrylate, ethoxypolyethylene glycol mono(meth)acrylate meth)acrylate, ethoxypolypropylene glycol mono(meth)acrylate, ethoxypolybutylene glycol mono(meth)acrylate,
Methoxypolyethylene glycol/polypropylene glycol mono(meth)acrylate, phenoxypolyethylene glycol mono(meth)acrylate, benzyloxypolyethylene glycol mono(meth)acrylate, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate and hydrophobic unsaturated monomers such as styrene, etc., and one or more of these can be used. Examples of the crosslinking agent (C) that can be used in the present invention include divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and propylene glycol di(meth)acrylate. , polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol di(meth)acrylate, N,N-methylenebisacrylamide, triallyl isocyanurate, trimethylolpropane diallyl Compounds having two or more ethylenically unsaturated groups in one molecule such as ether; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol,
polyvinyl alcohol, pentaerythritol,
Polyhydric alcohols such as sorbitol, sorbitan, glucose, mannitol, mannitan, sucrose, glucose; ethylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether , neopentyl glycol diglycidyl ether, 1,6-
Examples include polyepoxy compounds such as hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and glycerin triglycidyl ether, and one or more of these can be used. When a polyhydric alcohol is used as a crosslinking agent, it is preferable to carry out post-polymerization heat treatment at a temperature of 150°C to 250°C, and when a polyepoxy compound is used, a temperature of 50°C to 250°C is preferable. The use of crosslinking agents is
This is preferable because the crosslink density of the obtained crosslinked polymer can be freely controlled. The amount of the crosslinking agent used is preferably in a molar ratio to the monomer.
It ranges from 0.00001 to 0.3. If the molar ratio of the crosslinking agent exceeds 0.3, the crosslinking density of the crosslinked polymer obtained tends to be too high and the water absorption capacity tends to decrease.On the other hand, if the amount is less than 0.00001, the crosslinking density becomes small If too much is used, it becomes sticky after absorbing moisture, which may cause problems in handling. The polymerization method for obtaining a crosslinked polymer effective as a water stopper for optical/power cables according to the present invention may be any conventionally known method, such as a method using a radical polymerization catalyst, a method using a radiation/electron beam, etc.・Methods such as irradiation with ultraviolet rays etc. can be mentioned. Radical polymerization catalysts include hydrogen peroxide, peroxides such as benzoyl peroxide and kyumene hydroperoxide, azo compounds such as azobisisobutyronitrile, and radicals such as persulfates such as ammonium persulfate and potassium persulfate. Generating agents, these together with sodium bisulfite, L-ascorbic acid,
Redox initiators are used in combination with reducing agents such as ferrous salts. As the polymerization solvent, for example, water, methanol, ethanol, acetone, dimethylformamide, dimethyl sulfoxide, and mixtures thereof can be used.
The temperature during polymerization varies depending on the type of catalyst used, but a relatively low temperature is preferable because the molecular weight of the crosslinked polymer increases. However, in order to complete the polymerization, the temperature is preferably within the range of 20°C or higher and 100°C or lower. Although there is no particular restriction on the monomer concentration in the polymerization system, it is preferably in the range of 20 to 80% by weight, considering ease of control of the polymerization reaction, yield, and economy.
Various forms of polymerization can be adopted, including suspension polymerization, cast polymerization, and a method in which a gel-like hydrous polymer is polymerized while being fragmented using the shearing force of a double-arm kneader (Japanese Patent Laid-Open No. 57-34101). preferable. The water stop agent of the present invention may be used alone to fill the space inside the sheath of an optical/power cable, or it may be used to fill the space inside the sheath of an optical/power cable.
It may be filled by mixing with pulp, synthetic fibers, natural fibers, etc. Furthermore, by combining the water-stopping agent of the present invention with fibers, rubber, plastics, nonwoven fabrics, etc., it can be made into a water-stopping material with good workability during filling and a high water-stopping effect. Examples of these compounding methods include the following methods. A fibrous water-stopping material can be produced by adding a water-stopping agent to the spinning solution of synthetic fibers, etc., or by fixing the waterstopping material to a fibrous material such as synthetic fibers or natural fibers using an adhesive substance, etc. shall be. The fibrous water stop material may be filled into the sheath as it is, or may be used after being processed into a cloth shape. A water stop agent is kneaded into rubber or plastic, and processed using a roll or extruder to form a sheet or tape water stop material. Fix the water stop agent to a sheet or tape of non-woven fabric, paper, etc. using an adhesive substance, or
A sheet-like or tape-like water-stop material is obtained by sandwiching the water-stop agent between sheets of paper or tape. After applying a water-stopping agent mixed with an adhesive substance or paint to a plastic film or the like, the film is cut as necessary to form a sheet-like or tape-like waterstopping material. (Effects of the invention) If the water stopper of the present invention is used, even if seawater or groundwater enters the sheath of an optical/power cable, water will not move inside the sheath, and stable water stoppage will be achieved over a long period of time. Cables with excellent water performance and durability can be manufactured. Examples Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited only to these Examples. Example 1 21.6 g of sodium salt of 2-sulfoethyl methacrylate in a 500 ml cylindrical separable flask.
(0.10 mol), methacrylic acid 21.5 g (0.25 mol), sodium methacrylate 70.2 g (0.65 mol), N,
N-methylenebisacrylamide 0.92g (0.006
mol) and 170 g of water were added and stirred to uniformly dissolve. After purging with nitrogen, heat to 40°C in a hot water bath, add 1.0 g of 10% ammonium persulfate aqueous solution and 0.5 g of 1% L-ascorbic acid aqueous solution,
Stirring was stopped to allow polymerization. After polymerization starts, heat is generated,
The temperature rose to 95°C after 30 minutes. After confirming that the temperature of the polymerization system had begun to drop, the water bath was raised to 90°C and heated for an additional hour. The obtained water-containing gel of the crosslinked polymer was divided into small pieces, dried in a hot air dryer at 150°C for 3 hours, and pulverized to obtain the water-stopping agent (1) of the present invention. Example 2 In a 500 ml cylindrical separable flask, 157 g (0.70 mol) of ammonium 2-acrylamido-2-methylpropanesulfonate, 21.3 mol of acrylamide
(0.30 mol), 0.31 g (0.002 mol) of N,N-methylenebisacrylamide, and 270 g of water were stirred and uniformly dissolved. Thereafter, polymerization, drying, and pulverization were performed in the same manner as in Example 1 to obtain the water stop agent (2) of the present invention. Example 3 220 ml of n-hexane was charged into a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube, and 1.8 g of sorbitan monostearate was added and dissolved therein, and the flask was purged with nitrogen. In a dropping funnel, add 23.3 g (0.10 mol) of calcium salt of 3-sulfopropyl acrylate and 0.72 g of acrylic acid.
(0.01 mol), calcium acrylate 5.55g (0.05
mol), methacrylamide 4.25g (0.05mol), ethylene glycol diglycidyl ether 0.0174g
(0.0001 mol), 50 g of water and calcium persulfate
After adding and dissolving 0.05 g, nitrogen gas was blown into the aqueous solution to remove oxygen present in the aqueous solution. Then,
The contents of the dropping funnel were added to the four-necked flask and dispersed, and the polymerization reaction was continued for 3 hours by maintaining the temperature of the polymerization system at 60 to 65°C in a hot water bath while introducing a slight amount of nitrogen gas. After that, n-hexane was distilled off under reduced pressure, and the remaining hydrogel of the crosslinked polymer was heated to 90°C.
The water stop agent (3) of the present invention was obtained by drying under reduced pressure. Example 4 In a 1000 ml cylindrical separable flask, 51 g (0.2 mol) of monoethanolamine salt of 2-sulfoethyl methacrylate, 4.3 g (0.05 mol) methacrylic acid, 16.2 g (0.15 mol) sodium methacrylate, and methoxypolyethylene glycol mono 216 g (0.4 mol) of methacrylate (containing an average of 10 ethylene oxide units per molecule), N,
N-methylenebisacrylamide 0.154g (0.001
mol) and 250 g of water were added and stirred to uniformly dissolve. Thereafter, polymerization, drying, and pulverization were performed in the same manner as in Example 1 to obtain a water stop agent (4) of the present invention. Comparative Example 1 18 g (0.25 mol) of acrylic acid and 70.5 mol of sodium acrylate in a 500 ml cylindrical separable flask
(0.75 mol), 0.92 g (0.006 mol) of N,N-methylenebisacrylamide, and 135 g of water were charged and stirred to uniformly dissolve them. Thereafter, polymerization, drying, and pulverization were performed in the same manner as in Example 1, and a comparative water stopper was prepared.
I got (1). Examples 5 to 8 A diameter of 11 in a glass tube with a total of 15 mm and a length of 2000 mm.
A glass rod with a length of 2000 mm was inserted, and a gap of 2 mm was left between the inner wall of the glass tube and the surface of the glass rod. Into this gap, 18 g each of the water stoppers (1) to (4) of the present invention obtained in Examples 1 to 4 and 18 g of pulp were added.
A simulated cable was prepared by filling the mixture with g. Hold this simulated cable horizontally, and dissolve 37.6 g of Aqua Ocean (manufactured by Shin-Fuso Pharmaceutical Co., Ltd.) in deionized water on one end of the simulated cable.
Connect containers filled with artificial seawater obtained as
The liquid level in the container was maintained at a height of 1000 mm above the simulated cable. Next, we opened the lid at the bottom of the container, guided the artificial seawater into the simulated cable, and observed how the artificial seawater entered the simulated cable by measuring the distance from the end of the simulated cable to the tip where the artificial seawater had entered. evaluated. The results are shown in Table 1 along with the physical properties of the water stop agents (1) to (4) of the present invention used. Comparative Example 2 As a water stop agent, the comparative water stop agent obtained in Comparative Example 1
In the same manner as Examples 5 to 8 except for using (1),
A simulated cable was created and evaluated. The evaluation results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. 0.5 mg equivalent/g of sulfonic acid group or its salt
A water stop agent for optical/power cables comprising a crosslinked polymer containing the above and 1.0 mg equivalent/g or more of dissociative groups. 2. The water stop agent for optical/power cables according to claim 1, wherein the crosslinked polymer has a water absorption capacity for deionized water that is 5 times or more the weight of the crosslinked polymer. 3. The sulfonic acid group or its salt is one or more groups selected from the group consisting of sulfonic acid groups and sodium salts, potassium salts, calcium salts, magnesium salts, ammonium salts, and organic amine salts of sulfonic acid groups. A water stop agent for optical/power cables according to claim 1.