JP5325066B2 - Cold shrink tube for cable connection and cable connection - Google Patents

Description

  The present invention relates to a normal temperature shrinkable tube used for connecting a cable such as a CV cable (crosslinked polyethylene insulating cable), and a cable connecting portion using such a cold shrinkable tube.

  Conventionally, a cold shrink tube is used for the purpose of waterproofing, protection, insulation reinforcement, and the like in intermediate connection portions and terminal connection portions of power cables such as CV cables, or connection portions in terminals of communication cables (for example, (See Patent Document 1).

  This normal temperature shrinkable tube is a cylindrical body made of an elastic rubber material such as ethylene propylene rubber and is in a contracted state at normal temperature. For this reason, when mounting, it is necessary to expand the cold shrink tube in advance (hereinafter referred to as diameter expansion), and in order to maintain this expanded state, a diameter expansion holding member called an inner core is provided in the cold shrink tube. (Normally, the inner core is stored inside, that is, stored as a normal temperature shrinkable tube with an inner core). And it is arrange | positioned in the location which should be mounted | worn with the inner core inserted, Then, by pulling out an inner core, a normal temperature shrinkable tube shrink | contracts and it is mounted | worn in a predetermined position.

  Such room-temperature shrinkable tubes have excellent elongation characteristics due to diameter expansion, and good permanent elongation characteristics and stress relaxation characteristics (compression permanent strain) to ensure adhesion to the mounted surface after the inner core is pulled out It is required to have excellent damage resistance during use and storage (expansion of diameter).

  However, the conventional cold-shrinkable tube does not always satisfy these required characteristics, and there is a problem in that it tends to break in the axial direction, especially when scratched in the expanded diameter expanded state during storage. . In order to prevent breakage during diameter expansion, it is sufficient to increase the tensile strength. However, if the tensile strength is increased, the permanent elongation characteristics and stress relaxation characteristics become poor. Protection function, waterproof function, etc. cannot be obtained.

JP 2007-87664 A

  The present invention has been made in order to solve the above-mentioned problems. For cable connection parts, which have good trauma resistance, are less likely to break in an expanded and elongated state, and are excellent in permanent elongation characteristics and stress relaxation characteristics. An object of the present invention is to provide a cold-shrinkable tube and a cable connection portion including such a cold-shrinkable tube.

To achieve the above object, the invention described in claim 1, ethylene-propylene-diene terpolymer 100 parts by weight, per, CTAB specific surface area 75~170m ² / g, BET specific surface area of 150 to 250 ² / It is a normal temperature shrinkable tube for a cable connection part, comprising a crosslinked product of a composition containing 40 to 55 parts by mass of g of highly dispersible silica.

  The invention described in claim 2 is characterized in that the diene component of the ethylene / propylene / diene ternary copolymer is ethylidene norbornene (ENB) in the cold-shrinkable tube for cable connection part of claim 1. To do.

  The invention described in claim 3 is the room temperature shrinkable tube according to claim 1 or 2, wherein the composition has a compression set of 15% or less, a permanent elongation of 10% or less, and a tensile strength of 10 MPa or more. It is characterized by being.

  The invention described in claim 4 is the room temperature shrinkable tube for cable connection part according to claim 1 or 2, wherein the composition has a compression set rate of 10-13%, a permanent elongation of 5-8%, and a tensile strength. It is characterized by being 12 to 15 MPa.

  The invention described in claim 5 is characterized in that in the cold-shrinkable tube for a cable connection part according to any one of claims 1 to 4, the cable connection part is used for a waterproof protective tube. To do.

  A sixth aspect of the present invention is a cable connection portion comprising the cold-shrinkable tube for a cable connection portion according to any one of the first to fifth aspects.

  According to the present invention, the normal temperature shrinkable tube for a cable connection part, which has good trauma resistance, is not easily broken in an expanded diameter state, and has excellent permanent elongation characteristics and stress relaxation characteristics, and such normal temperature shrinkage. A cable connection with a tube can be provided.

It is sectional drawing which shows the cable connection part which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be described below.

The normal temperature shrinkable tube for cable connection part of the present invention uses an ethylene / propylene / diene terpolymer as a base resin, and based on 100 parts by mass of the base resin, a CTAB specific surface area of 75 to 170 m ² / g, a BET specific surface area of 150 It is comprised from the crosslinked body of the composition which contains 40-55 mass parts of highly dispersible silica of -250m < ² > / g.

  The ethylene / propylene / diene terpolymer is not particularly limited, and known ones can be used. Specifically, for example, ethylene and propylene copolymerized with ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene or the like as a diene component is used. The ethylene / propylene / diene terpolymer may be used alone or in combination of two or more. Examples of commercially available products include Tarprene 3130S, Mitsui EPT 4070, Mitsui EPT9070E, Mitsui EPT4045, Mitsui EPT8070E, Mitsui EPT4095, Mitsui EPT4021, made by Mitsui Chemicals, NORDEL IP4570 made by Dow Chemical Japan, and Nippon Synthetic Rubber JSREP25, JSREP35, JSREP37C, JSREP65 (all are trade names) and the like. As the ethylene / propylene / diene terpolymer, it is preferable to use Tarprene 3130S manufactured by Mitsui Chemicals, NORDEL IP4570 manufactured by Dow Chemical Japan, and JSREP25 manufactured by Nippon Synthetic Rubber.

Furthermore, highly disperse silica, it shows a particularly high dispersibility among precipitated silicas, in the present invention, in particular, with a CTAB specific surface area of 75~170m ² / g, and a BET specific surface area of 150 to 250 ² / Use g. Preferred examples of the highly dispersible silica include, for example, Zeopole 8715, Zeopole 8745 manufactured by Hoover, Hisil 2000 manufactured by PPG, Zeosil 1165MP, Zeosil 1115MP manufactured by Rhodia, BV 3380 manufactured by Degussa, and Perkasil K1430 manufactured by Akzo. (All of the above are trade names). High dispersibility silica may be used individually by 1 type, and may mix and use 2 or more types.

  As the highly dispersible silica, use of Zeole 8715 and Zeole 8745 having the following physical properties is particularly preferable.

  In addition, the CTAB specific surface area and BET specific surface area of the said Zeopole 8715 and Zeopole 8745 are the values measured based on HUBER CHEMICALS TEST METHODS.

The content of the highly dispersible silica is 40 to 55 parts by mass per 100 parts by mass of the ethylene / propylene / diene terpolymer of the base resin. When the content is less than 40 parts by mass, fracture becomes Ku ease occur in expanded stretched state without effect is obtained according to the present invention. Moreover, when it exceeds 55 mass parts, a permanent elongation characteristic and a stress relaxation characteristic will fall. A more preferable range of the highly dispersible silica content is 44 to 52 parts by mass per 100 parts by mass of the ethylene / propylene / diene terpolymer.

  A crosslinking agent such as an organic peroxide can be blended in the composition forming the cold shrink tube. Examples of organic peroxides include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di -(Tert-butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n -Butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl oxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroylper Oxide, tert-butyl kumi Peroxide. These may be used individually by 1 type, and 2 or more types may be mixed and used for them. Among them, dicumyl peroxide is preferable as the crosslinking agent. The organic peroxide is usually blended in an amount of 2 to 6 parts by mass with respect to 100 parts by mass of the ethylene / propylene / diene terpolymer.

  Further, when an organic peroxide is used as the crosslinking agent, the damage resistance and stress relaxation characteristics can be further improved by adding a crosslinking aid. Examples of the crosslinking aid include zinc acrylate, zinc methacrylate, NN′-m-phenylene dimaleimide, triallyl isocyanurate, and polyfunctional methacrylate monomer.

  Furthermore, in the composition, processing aids, flame retardants, anti-aging agents, UV absorbers, colorants, softeners, plasticizers, lubricants, etc., which are usually blended in ethylene / propylene / diene terpolymers These additives can be blended within a range that does not impair the effects of the present invention. Moreover, you may use inorganic fillers other than the said highly dispersible silica in the range which does not inhibit the effect of this invention.

The composition forming the cold-shrinkable tube preferably has a Mooney viscosity ML ^{1 + 4 at} 100 ° C. of 45 or less, a Mooney viscosity ML ^{1 + 4 at} 125 ° C. of 40 or less, and a Mooney viscosity ML ^{1 + 4 at} 100 ° C. of 30 to 40, 125. More preferably, the Mooney viscosity ML ^{1 + 4} at 25 ° C. is 25 to 35. Mooney viscosity ML ^{1 + 4 at} 100 ° C. and 125 ° C. can be measured based on JIS K 6300-1 (unvulcanized rubber—physical properties—part 1: how to determine viscosity and scorch time using Mooney viscometer).

  The cold-shrinkable tube of the present invention is obtained by uniformly mixing the above components using a kneader or the like to obtain a rubber compound, molding this into a tube shape, and then crosslinking by a conventional method.

  The cold-shrinkable tube thus obtained has good trauma resistance, is not easily broken in the expanded and elongated state, and has excellent permanent elongation characteristics and stress relaxation characteristics. Therefore, a highly reliable cable connection part can be formed using this.

  The normal temperature shrinkable tube of the present invention preferably has a compression set of 15% or less, more preferably 10 to 13%. If the compression set exceeds 15%, the adhesion to the mounted surface after the inner core is pulled out at the time of diameter expansion is lowered. The compression set rate is measured according to JIS K 6262 (vulcanized rubber and thermoplastic rubber—how to obtain compression set at normal temperature, high temperature and low temperature).

The room temperature shrinkable tube of the present invention preferably has a permanent elongation of 10% or less,
More preferably, it is 5 to 8%. When permanent elongation exceeds 10%, the adhesiveness with respect to the to-be-mounted surface after inner core drawing will fall. Permanent elongation is measured in accordance with JIS K 6273 (vulcanized rubber and thermoplastic rubber-how to determine tensile permanent strain, elongation rate and creep rate).

  Furthermore, the normal temperature shrinkable tube of the present invention preferably has a tensile strength of 10 MPa or more, more preferably 12 to 15 MPa. When the tensile strength is less than 10 MPa, the normal temperature shrinkable tube is easily broken during diameter expansion. The tensile strength is measured in accordance with JIS K 6251 (vulcanized rubber and thermoplastic rubber—how to obtain tensile properties).

  Next, the cable connection part using the cold shrinkable tube of the present invention will be described.

  FIG. 1 is a longitudinal sectional view showing an example of a cable connecting portion using the cold shrinkable tube of the present invention. This example is an example in which the cold shrinkable tube of the present invention is used as a waterproof protective tube for a cable connection portion.

  In FIG. 1, reference numeral 1 indicates a pair of power cables to be connected. Each of these power cables 1, 1 is stepped off, and the cable conductor 2 and the cable insulator 3 are exposed, respectively. The cable conductors 2 are connected to each other by a conductor connecting pipe 4, and an insulating cylinder 5 is mounted on the conductor connecting pipe 4 across the cable insulators 3 and 3. The insulating cylinder 5 has a structure in which an inner electrode 5b and an outer electrode 5c having semiconductivity are provided on the inner peripheral surface and the outer peripheral surface of an insulating cylinder main body 5a having insulating properties, respectively. A braided mesh 6 is provided outside the insulating cylinder 5, and a room temperature shrinkable tube 7 of the present invention is attached so as to cover the braided mesh 6.

  Prior to use, the cold shrink tube 7 is inserted with a cylindrical expanded holding member called an inner core to maintain the expanded diameter, and the cable is passed through and placed at a predetermined position. It is attached by removing. By pulling out the support material, the cold shrink tube 7 is reduced in diameter and fixed at a predetermined position.

  An insulating tape 9 is wound around the cable 1 (cable sheath 8) at both ends of the cold shrink tube 7, and a semi-conductive layer such as an ACP tape is formed on the cable outer semiconductive layer (not shown). A conductive fusion tape 10 is wound.

In thus constructed cable connection, as a waterproof protective tube, ethylene-propylene-diene terpolymer 100 parts by weight, per, CTAB specific surface area 75~170m ² / g, BET specific surface area of 150 to 250 ² / Since the normal temperature shrinkable tube made of a crosslinked product of the composition containing 40 to 55 parts by mass of highly dispersible silica of g is used, the normal temperature shrinkable tube itself is prevented from being broken, and the normal temperature shrinkable tube and the insulating cylinder are The adhesion is also good. Therefore, excellent waterproof properties can be maintained.

  In addition, although the said embodiment is an example of the intermediate connection part which used the normal temperature shrinkable tube of this invention as a waterproofing protection tube, this invention is not limited to such an example, It mounts | wears on a conductor connection pipe | tube. It can also be used as an insulating reinforcing tube. Further, the connecting portion is not limited to the intermediate connecting portion, and can be applied to a cable terminal portion or the like. When used as an insulating reinforcing tube, a highly reliable insulating reinforcing body can be formed.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Example 1
Ethylene / propylene / diene terpolymer (EPDM; manufactured by Mitsui Chemicals, Inc.)
Tarprene 3130S) 147 parts by mass, highly dispersible silica (trade name Zeopole 8715 manufactured by Hoover, CTAB specific surface area 90 m ² / g, BET specific surface area 120 m ² / g; expressed as silica (i)) 15 parts by mass, process oil 60 parts by mass Parts, paraffinic preservatives (trade name PS-430, manufactured by Idemitsu Kosan Co., Ltd.), anti-aging agents (trade name Nocrack MB, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) 1.75 parts by mass, 1 part by mass of polyethylene glycol, lubricant (Schill and) Seiracher, Inc., trade name: Sractol WB-16) 2 parts by mass, 1 part by mass of stearic acid, 5 parts by mass of zinc oxide, 2.4 parts by mass of dicumyl peroxide, 2.5 parts by mass of zinc methacrylate as a crosslinking aid , And 2 parts by mass of carbon black were uniformly kneaded with a 75 L kneader and then rolled with an 8-inch roll. Extruding the bets shape by performing press-molding vulcanization 170 ° C. × 25 minutes to prepare a 2mm thick sheet.

(Examples 2-6, Comparative Examples 1 and 2)
In the same manner as in Example 1, a sheet having a thickness of 2 mm was produced using the components shown in Table 1 in the amounts shown in Table 1. Components other than the components used in Example 1 are as follows.
Silica (ii):
Product name Zeopole 8745; CTAB specific surface area 140 m ² / g, BET specific surface area 180 m ² / g
Silica (iii):
Product name Nippon Sil RS-150; CTAB specific surface area 70 m ² / g, BET specific surface area 85 m ² / g

  About the sheet | seat obtained by each Example and each comparative example, tensile stress, tensile strength, elongation, hardness, tear strength, compression set rate, and permanent elongation were measured. Further, the Mooney viscosity at 100 ° C. and 125 ° C. was measured for the kneaded product before molding. The measuring method is as follows.

[Mooney viscosity]
A Mooney viscometer (L-shaped rotor) was used, and measurement was performed based on JIS K 6300-1 with a preheating time of 1 minute and test temperatures of 100 ° C. and 125 ° C.
[Tensile stress]
Tensile stress at 100% elongation was measured based on JIS K 6251 (vulcanized rubber and thermoplastic rubber—how to obtain tensile properties).
[Tensile strength, elongation]
Measurement was performed based on JIS K 6251.
[Hardness]
It was measured with a type A durometer specified in JIS K 6253 (vulcanized rubber and thermoplastic rubber—how to obtain hardness).
[Tear strength]
Measured based on JIS K 6252 (vulcanized rubber and thermoplastic rubber—how to determine tear strength).
[Compression set rate]
In accordance with JIS K 6262 (vulcanized rubber and thermoplastic rubber—how to obtain compression set at normal temperature, high temperature and low temperature), the measurement was performed at 150 ° C. for 72 hours.
[Permanent elongation]
The dumbbell-shaped No. 3 test piece specified in JIS K 6251 is held in a constant temperature bath at 80 ° C. for 72 hours in an extended state and then opened. The rate of change of the distance between the marked lines after the extension with respect to the distance between the previous marked lines was obtained.

  These results are shown in the lower column of Table 1.

  As is apparent from Table 2, the sheets obtained in the examples have high tensile strength, elongation, and tear strength, but have good compression set characteristics and permanent elongation characteristics that are contrary to those characteristics. It was fully equipped with the properties required for cold shrink tubing.

  DESCRIPTION OF SYMBOLS 1 ... Electric power cable, 2 ... Cable conductor, 3 ... Cable insulator, 4 ... Conductor connection pipe, 5 ... Insulation cylinder, 6 ... Braided mesh, 7 ... Cold shrink tube, 8 ... Cable sheath, 9 ... Insulation tape, 10 ... Semi-conductive fusing tape.

Claims (6)

Ethylene-propylene-diene terpolymer 100 parts by weight, per, CTAB specific surface area 75~170m ² / g, the high dispersibility of silica containing 40 to 55 parts by weight composition of the BET specific surface area of 150 to 250 ² / g A cold-shrinkable tube for cable connection parts, characterized by comprising a crosslinked body.   The normal temperature shrinkable tube for a cable connection part according to claim 1, wherein the diene component of the ethylene / propylene / diene terpolymer is ethylidene norbornene. The normal temperature shrinkable tube for a cable connection part according to claim 1 or 2, wherein the composition has a compression set of 15% or less, a permanent elongation of 10% or less, and a tensile strength of 10 MPa or more. The normal temperature shrinkable tube for a cable connection part according to claim 1 or 2, wherein the composition has a compression set rate of 10 to 13%, a permanent elongation of 5 to 8%, and a tensile strength of 12 to 15 MPa.   The cold-shrinkable tube for a cable connection part according to any one of claims 1 to 4, wherein the tube is used for a waterproof protection tube in a cable connection part.   A cable connecting part comprising the cold-shrinkable tube for a cable connecting part according to any one of claims 1 to 5.

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