JPH07320558A - Semiconductive cushion tape for power cable - Google Patents

Abstract

PURPOSE:To absorb thermal expansion/contraction of a core so as to prevent damage by impregnating a knitted or woven object of specific thickness with a semiconductive synthetic rubber composition solvent solution or by applying it dried and vulcanized, in an annular loop pile of synthetic fiber multifilament system. CONSTITUTION:In a knitted object of 0.3 to 3.0mm thickness having an annular loop pile (ring) 1 of synthetic fiber multifilament system in a thickness direction usable in a semiconductive cushion tape, a thread, which must be a pile, is protruded as a large loop (ring) on a ground surface during knitting. The semiconductive cushion tape is manufactured by impregnating a knitted and woven object with a semiconductive synthetic rubber composition organic solvent solution or applying it dried further vulcanized by high temperature hot air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-conductive cushion tape suitable for holding a rubber / plastic insulated power cable.

[0002]

2. Description of the Related Art Generally, rubber / plastic (for example, cross-linked polyethylene) having a metal sheath such as a corrugated aluminum sheath and a stainless sheath on the outside.
With insulated power cables, the insulating core expands and contracts in the radial direction up to a diameter of 2 to 4 mm due to temperature changes such as changes in the heat cycle of energization and power outage, or changes in the outside air temperature. (The thickness of the insulating layer depends on the thickness of the insulating layer, the temperature change width, etc.), whereas the inner diameter of the outer metal sheath changes only 100 μm or less in a normal temperature range.

Therefore, when the insulating core expands, the insulating core may come into contact with the inner surface of the metal sheath and be damaged or dented.

In order to prevent such a phenomenon, it is sufficient to previously provide a sufficient gap between the insulating core and the metal sheath. However, when such a gap is provided, when the cable is laid. Or, due to thermal behavior after installation, the metal sheath and the insulating core move differently, causing a shift. Further, when the metal sheath and the outermost semiconductive layer of the outermost layer of the insulating core need to be constantly in contact with each other, a large gap causes incomplete contact.

As a method for solving the above-mentioned problems, an insulating core formed by sequentially forming an inner semiconductive layer, a crosslinked polyethylene insulating layer and an outer semiconductive layer on a conductor by extrusion or the like has a long length on the outer periphery. There is a method of using an external semiconductive layer having a gear-shaped cross-sectional shape having a plurality of protrusions in the depth direction. However, when forming an insulating core having a gear-shaped outer semiconductive layer with protrusions on the outermost layer, the structure of the die during extrusion becomes complicated, especially when the insulating layer is crosslinked polyethylene The molded insulating core is cross-linked under high temperature and high pressure and then post-cooled.However, it is difficult to make the insulating core because it has a protrusion on the surface and it is difficult to make the insulating core, and it is difficult to secure the performance of the main insulation. There is a point.
Further, the external semiconductive layer formed by extrusion does not always have sufficient absorption characteristics of repeated thermal expansion / contraction because the material is selected mainly for workability and electric performance.

In order to solve the above-mentioned problems, a winding layer of a semiconductive cushion tape is provided between the insulating core and the metal sheath, and the thermal expansion / contraction of the insulating core is absorbed by the semiconductive cushion tape. A rubber and plastic insulated power cable having a metal sheath is disclosed in JP-A-64-12405.
It is proposed in Japanese Patent Publication No.

That is, FIG. 3 is a cross-sectional view of a concrete example of a rubber / plastic insulated power cable in which a semiconductive cushion tape is provided between an insulating core and a metal sheath.

In the drawing, (A) is an insulating core, which is an insulating layer (13) such as an inner semiconductive layer (12), crosslinked polyethylene, synthetic rubber, etc. on a conductor (11) such as a circular compressed conductor or a divided circular compressed conductor. ) And an external semiconductive layer (14) having a smooth surface are sequentially formed by extrusion or the like.

A winding layer (15) of semiconductive cushion tape is provided on the insulating core (A), and a shielding layer formed by combining winding layers such as copper wire woven semiconductive tape is provided on the winding layer (15). (16) is provided, and a corrugated metal sheath (18) of aluminum, stainless steel or the like is provided on the gap (17) with a diameter of about 1 mm.
On top of that, an anticorrosion layer (19) such as polyvinyl chloride or polyethylene is applied. The semi-conductive cushion tape is formed by abutting or open winding of two sheets each having a pitch shifted by ½. The semi-conductive cushion tape absorbs thermal expansion and contraction of the insulating core by its unique cushioning property, that is, elasticity, adheres closely to the insulating core, and behaves integrally with the insulating core for a long period of time, and is electrically connected to the metal sheath. Contact is obtained over a long period of time.

As the semiconductive cushion tape,
The texture of the weave is relatively coarse, 1 mm or more, the weaving directions of the warp and weft threads substantially match the length direction and width direction of the tape, and the transverse direction is the bias direction. A semi-conductive elastic body coated or attached (Japanese Patent Laid-Open No. 64-1)
2405) or a woven fabric of synthetic fibers, the semiconductive rubber composition is applied and dried, and the foamable semiconductive rubber composition is topped on one side and foamed and vulcanized (Japanese Patent Publication No.
7478).

[0011]

However, each of the conventional semiconductive cushion tapes has the following problems. As described in JP-A-64-12405,
When applying a semi-conductive elastic body to both sides of a coarsely textured base fabric, the texture is very rough, being 1 mm or more, so if the solvent solution of the semi-conductive elastic body is actually applied and dried, Innumerable pinholes are generated between the eyes, the thickness of the base cloth hardly increases,
It cannot play the role of the cushion layer, and as a result, the above problems cannot be solved. Therefore, on both sides of the textured base fabric,
There is no choice but to stick a sheet of a semiconductive elastic body to a thickness of 0.3 to 1.5 mm described in the patent publication. Therefore, for example, the warp thread has a diameter of 0.25 mm and the weft thread has a diameter of 0.25 mm.
When 0.30 mm thick semi-conductive elastic sheets are topped on both sides of a coarse base fabric of mm with a calendering device, the maximum thickness (the part where the warp and the weft of the base fabric intersect) Is about 1.10 mm and the minimum thickness (interwoven portion where warp and weft is not present) is about 0.60 mm. In this case, an expensive semiconductive elastic body having a total thickness of 0.60 mm on both sides of the base fabric (assuming the specific gravity of the elastic body is 1.2, a large amount of semiconductive elastic body with a unit mass of about 720 g / m ^2). The unit mass is very heavy and the unit mass is very heavy, and it is necessary to vulcanize the semiconductive elastic body in order to have better elasticity, and special vulcanization equipment, liner and Since it takes a long time, it is very expensive and economically disadvantageous. Conversely, if the thickness of the semi-conductive elastic body is reduced and the thickness of the base cloth is increased to make it lighter and cheaper, the unevenness of the surface becomes larger, making it difficult to bond the semi-conductive elastic body and the base cloth. Moreover, the elasticity of the elastic body is lost because the elastic body is too thin, and as a result, the role of the cushion layer cannot be fulfilled.

On the other hand, in the case of producing the semi-conductive cushion tape described in Japanese Patent Publication No. 43-7478, first, a woven fabric is impregnated with a solvent solution of a semi-conductive rubber composition, or coated and dried, and half-coated on one side. The conductive rubber composition must be topped and then vulcanized and foamed, which complicates the process. Further, the vulcanizable / foamable semi-conductive rubber composition that must be topped is a natural rubber or a synthetic rubber, a conductive agent (for example, acetylene black), a foaming agent, a softening agent, a vulcanizing agent, a vulcanization aid, It contains processing aids and requires a high degree of control over the timing of vulcanization and foaming, which is very delicate and may result in loss of the composition. In the vulcanization / foaming process, if a simple and inexpensive high temperature hot air vulcanization facility is used, the gas released from the foaming agent escapes from the surface and the foaming degree decreases, resulting in a foam structure of the vulcanized foam. Becomes continuous bubbles,
There is a problem that the foam is dented due to the expansion of the insulating core, and the dent does not return to the original state even if the insulating core contracts. Therefore, it has to be vulcanized and foamed by a very expensive continuous press vulcanizer simulating press vulcanization, for example, a rotocure equipment, the production speed is slow, and as a result, a very expensive tape is obtained. It is economically disadvantageous. Further, for example, a woven fabric having a thickness of 0.10 mm (a unit mass of about 70 g /
m ² ) is impregnated with a solvent solution of a semiconductive synthetic rubber composition at a unit mass of about 30 g / m ² , or is applied and dried, and one side thereof is vulcanized and foamed with a semiconductive property of about 0.45 mm. A synthetic rubber composition (for example, when the specific gravity of the composition is 1.2, a unit mass of about 540 g / m ² ) is topped, and the continuous press vulcanizer is used to vulcanize and foam to a foaming ratio of about 2 times. As a result, a semiconductive cushion tape having a thickness of 1.0 mm and a unit mass of about 640 g / m ² is obtained, but the vulcanizable / foamable composition is very expensive and the unit mass is heavy.

As described above, the present invention has various problems of the semi-conductive cushion tapes that have been proposed in the related art. Particularly, since a large amount of semi-conductive synthetic rubber composition is used, the unit mass is very heavy and the special (EN) Provided is a semi-conductive cushion tape which uses a topping step and a special vulcanization method and is very expensive because of its slow production rate.

The object of the present invention is that it can be used for a rubber / plastic insulated power cable having a structure as shown in FIG. 3, can be manufactured at high speed without complicated and special manufacturing process and equipment, and the repeated thermal expansion of the insulating core. -It has a sufficient absorption property of contraction and can effectively follow the expansion and contraction of the cable core due to power supply / power failure or temperature change of the outside air temperature, and does not damage the insulating core such as scratches or dents. Then, it is to provide an inexpensive semi-conductive cushion tape.

[0015]

The semi-conductive cushion tape for electric power cables of the present invention has an annular loop pile (ringna) of synthetic fiber multifilament yarn in the thickness direction and has a thickness of 0.3 mm to 3.0 mm. The semi-conductive synthetic rubber composition solvent solution is impregnated into the knitted fabric or the woven fabric, or is applied and dried, and then vulcanized.

In the above-mentioned semi-conductive cushion tape for electric power cables, the synthetic fiber multifilament yarn constituting the annular loop pile (ringna) of the knitted fabric or the woven fabric can be a textured yarn.

Furthermore, in the above-mentioned semi-conductive cushion tape for electric power cables, the knitted fabric or woven fabric is previously 150-2.
It may be heat set at a high temperature of 10 ° C.

As described above, the conventional semiconductive cushion tape requires the absorption characteristics of the repeated thermal expansion and contraction of the insulating core to the uneven elasticity and the foam structure elasticity of the semiconductive synthetic rubber composition. The semiconductive cushion tape of the invention is
We are looking for absorption characteristics in a entangled network structure of special fibers, therefore, it requires only a small amount of semiconductive synthetic rubber composition, can be simply impregnated, or can be manufactured at high speed by coating and drying and high temperature hot air vulcanization, Light weight, cheap and very economical.

0.3 mm to 3.0 having an annular loop pile (Wanna) of synthetic fiber multifilament yarn in the thickness direction which can be used for the semiconductive cushion tape of the present invention.
The mm knitted fabric is a fabric in which the yarn to be a pile is projected as a large loop (wanna) on the fabric surface during knitting, and the outer surface is covered with the pile, and is generally called a pile fabric.
For example, we knit a plain knit with a fine thread for the ground weaving yarn, weave a ground weaving thread with a thick yarn for the fleece yarn, weave a pile on the back side, and a pile yarn to be napped on the back yarn. There are napped knitting in which a pile is formed on one side of the fabric by splicing and knitting, and pile knitting in which a pile is formed in a ring shape on the surface of the knitted fabric, but the knitting methods are not limited to these.

The woven fabric having a thickness of 0.3 mm to 3.0 mm having an annular loop pile of synthetic fiber multifilament yarns in the thickness direction which can be used for the semi-conductive cushion tape of the present invention is a woven fabric having a pile on one side. Generally, it is called a pile fabric, for example, weft pile weave and warp pile weave, but the weaving methods are not limited to these.

The material of the above-mentioned knitted fabric of the semi-conductive cushion tape of the present invention or the ground yarn of the woven fabric, that is, the yarn that does not form the annular loop pile is synthetic fiber,
Any filament or spun yarn of natural fiber, chemical fiber, or a mixture thereof may be used as long as it does not shrink at a temperature of 100 ° C. or after heat setting, for example, polyester, nylon, cotton, rayon, high tenacity. Viscose rayon, vinylon, etc., the thickness of the thread,
It is determined by the gauge of the knitted fabric or the density of the woven fabric and the type of the knitting machine or the loom.
-120th place. Further, it is desirable that the ground yarn knitted fabric has a high tensile strength at 5% elongation in the longitudinal direction and a low tensile strength in the transverse direction. This is because if the tensile strength at the time of stretching in the longitudinal direction by 5% is low, the width of the tape becomes narrow during semi-conductivity / vulcanization and during use of the tape. If the tensile strength in the transverse direction is low at 5%, the tape is generally wound around the insulating core at an angle of 45 degrees, so that the tape follows the expansion and contraction well even when the insulating core thermally expands and contracts. . Pile woven fabrics can also have such characteristics by a combination of various processes, that is, by weaving using a high shrinkage yarn for the horizontal ground yarn and shrinking in the transverse direction at the time of heat setting, but it is expensive. Is more advantageous.

The material of the synthetic fiber multifilament yarn constituting the annular loop pile of the above-mentioned knitted fabric or woven fabric of the semiconductive cushion tape of the present invention includes polyester, nylon, aramid, polyarylate, and heterocyclic ring-containing aromatic polymer ( It is a filament yarn such as polybenzazole), and the thickness of the yarn is similar to that of the ground yarn. Fibers of aramid, polyarylate, and aromatic ring-containing aromatic polymers can be used as they are because they have heat resistance of 300 ° C or more by themselves, but polyester and nylon have considerably poor heat resistance, so at high temperatures of 150-210 ° C. It is desirable to heat set. That is, when the power cable is energized, it is about 9
This is because the conductor is heated to 0 ° C. and heat of about 70 ° C. is applied to the tape for a long period of time, and at that time, heat setting prevents the fiber yarn from shrinking. In addition, these yarns are used to form a loop loop pile in the thickness direction on a knitted fabric or woven fabric,
These yarns are given a elasticity that absorbs the thermal expansion and contraction of the insulating core. Therefore, these yarns are crimped into synthetic fiber multi-filament yarns and heat set to make them bulky, stretchable and elastic. Textured yarns are particularly suitable. These textured yarns are processed by the well-known false twist method, knit de knit method, indentation method, rubbing method, jet method, or the like.

The gauge of the above-mentioned knitted fabric of the semi-conductive cushion tape of the present invention (meaning the number of stitches in a unit section showing the needle density of a knitting machine, in this case, the number of stitches in 1 inch) is
The base yarn and the annular loop pile forming yarn may be changed, but they are generally almost the same, and it is preferable that the yarn is as large as possible, and 20 or more, particularly 25 or more is preferable. If it is less than 20, the structure is too coarse and the tensile strength at the time of 5% elongation in the longitudinal direction is low, and the width of the knitted fabric or tape becomes narrow at the time of semiconducting processing or winding on a cable. This is because the number of annular loop piles is small and sufficient elasticity cannot be obtained.

The thickness of the above-mentioned knitted fabric or woven fabric of the semiconductive cushion tape of the present invention is 0.3 mm to 3.0 mm, particularly preferably 0.5 mm to 1.5 mm. 0.
If it is less than 3 mm, it is too thin to obtain sufficient elasticity, that is, absorption characteristics, and if it is 3.0 mm or more, the height of the loop of the fiber thread becomes large and the insulating core remains dented when contracted after thermal expansion is sufficient. This is because no elastic recovery is obtained.

The knitted or woven fabric used for the semi-conductive cushion tape of the present invention is knitted or woven, then scoured and heat set at a high temperature of 150 to 210 ° C. for several tens of seconds. By this heat setting, the knitted fabric or the woven fabric is thermally fixed, the knitted fabric or the woven fabric is prevented from shrinking due to the high temperature during drying and vulcanization during the semiconductive treatment, and the cable is energized to the tape. This is because even if heat of 70 ° C. is applied for a long period of time, shrinkage of the loop loop pile of the synthetic fiber multifilament yarn in the thickness direction of the tape itself and the knitted fabric or the woven fabric, that is, the looper, is further prevented.

The semiconductive synthetic rubber composition impregnated or applied to the above-mentioned knitted fabric or woven fabric of the semiconductive cushion tape of the present invention is a butyl rubber or ethylene propylene terpolymer rubber having good aging resistance. , Acetylene black or conductive furnace black as a conductive agent, vulcanizing agent such as quinone and peroxide, vulcanization aids such as zinc white, red lead, organic and inorganic compounds, softening agents, tackifiers, anti-aging agents In general, it is 10 ¹ to 10 ³ Ω-c.
It has a volume resistivity of m. These compositions are kneaded in a Banbury mixer excluding the vulcanizing agent, added with a vulcanizing agent in an open roll at low temperature, and impregnated as an organic solvent solution dissolved in an organic solvent such as toluene or rubber volatile oil,
Used for coating.

The semiconductive cushion tape of the present invention is produced by impregnating or coating the above knitted fabric or woven fabric with the organic solvent solution of the semiconductive synthetic rubber composition, coating and drying, and further vulcanizing with high temperature hot air. This vulcanization vulcanizes the semiconductive synthetic rubber composition adhering to the fibers of the knitted fabric and the woven fabric so that the composition loses its tackiness, and the cable is energized to thermally expand the insulating core and cover the fiber yarn. When the composition is dented together with the annular loop pile of the synthetic fiber multifilament yarn of the knitted fabric / woven fabric, it does not stick to each other, and the property that the dent returns to its original state after shrinkage is imparted. The amount of the semiconductive synthetic rubber composition attached to a knitted fabric or a woven fabric varies depending on the structure, thickness or unit mass of the knitted fabric or the woven fabric, but is generally 1/4 of the unit mass of the knitted fabric or the woven fabric. 10 ⁶ Ω-c required for ~ 1/2
A volume resistivity of m or less is obtained.

[0028]

As shown in FIG. 1, the semiconductive cushion tape of the present invention has an annular loop pile (Wanna) 1 of synthetic fiber multifilament yarn coated with a vulcanized semiconductive synthetic rubber composition. Thickness in the direction 0.3 mm-3.0 mm
Of knitting or woven fabric, and the knitting or woven fabric has an annular loop pile of multifilament yarn entwined with the ground structure 2 in the thickness direction and has a mesh structure as if it were a foam. When this mesh structure is wound so as to contact the insulation core of the cable and the insulation core thermally expands due to energization, this mesh structure is compressed and absorbs expansion and contraction of the insulation core sufficiently, and the insulation core is not damaged or dented. It will not be damaged.

Further, the synthetic fiber multifilament yarn for imparting an annular loop pile (Ranna) in the thickness direction to a knitted fabric or woven fabric used for the semiconductive cushion tape of the present invention,
If the textured yarn shown in FIG. 2 is crimped, it gives a three-dimensional mesh structure to the pile surface,
The ability of the insulating core to absorb thermal expansion and contraction is further increased significantly.

Further, when the above-mentioned knitted fabric / fabric of the semiconductive cushion tape of the present invention is previously heat set at a high temperature of 150 to 210 ° C., shrinkage of the knitted fabric / fabric due to the high temperature during the semiconductive treatment is prevented. There is no shrinkage in width or length,
The knitted fabric or the woven fabric can be effectively used, and even after the tape is stored in the cable, the shrinkage of the width of the tape and the shrinkage of the annular loop pile of the synthetic fiber multifilament yarn due to the heat when the cable is energized are further prevented.

In the semiconductive cushion tape of the present invention, when the base material is a knitted fabric or a woven fabric which is processed so as to be stretched in the lateral direction, the tape is wound around a cable at an angle of 45 degrees and is housed in the insulating core. Even if it expands or contracts, it stretches and follows in the transverse direction like the woven fabric in the bias direction, and is not cut during the use of the cable. Further, since the semiconductive cushion tape of the present invention is coated with a vulcanized semiconductive synthetic rubber composition in which all the fibers of the above knitted fabric are vulcanized,
Even if the insulating core is thermally expanded and compressed and the insulating core subsequently contracts, the original thickness is restored, and since the insulating core has a volume resistivity of 10 ⁶ Ω-cm or less, it is suitable as a semiconductive tape. Be effective.

Further, the semi-conductive cushion tape of the present invention has high productivity because it can be processed at high speed by ordinary impregnation or coating / drying equipment and a high temperature hot air vulcanizer, like ordinary semi-conductive tape. It is inexpensive and economically advantageous, and the amount of the above-mentioned expensive semi-conductive synthetic rubber composition attached is significantly smaller than that of the conventional cushion tape, so that it is inexpensive and lightweight.

[0033]

EXAMPLE A 75 denier continuous filament yarn made of 30 polyester fibers as a base yarn, a 75 denier continuously textured yarn made of 24 polyester fibers as a pile forming yarn, and 50 polyester fibers as a splicing yarn. A continuous double sided knitting machine consisting of 75 denier is used to knit a fleece knitted fabric with a circular double-sided knitting machine in both length and width of 28 gauge, scouring, and a heat setting machine at a high temperature of 180 ° C for 40 seconds. Processed, thickness 1.0 mm,
A heat-set knitted fabric having loops of polyester fiber textured yarn with a unit mass of 325 g / m ² was obtained. Next, 100 parts by weight of butyl rubber, 15 parts by weight of process oil (softening agent), 3 parts by weight of stearic acid (processing aid), 5 parts by weight of coumarone resin (tackifier), 4 parts by weight of petrolatum (softening agent), zinc 5 parts by weight of flower, 3 parts by weight of dibenzothiazole disulfide (vulcanization accelerator) and 90 parts by weight of acetylene black were kneaded in a laboratory Banbury mixer, and after cooling, a paraquinone dioxime (quinone) was prepared with an open laboratory roll. System non-sulfur vulcanizing agent) and volume resistivity 2.5 × 10 ² Ω−
A uniform semiconductive synthetic rubber composition having a size of cm was obtained. This composition was cut into a chip state with a rubber cutting cutter, placed in a container together with 500 parts by weight of toluene (organic solvent), allowed to stand for 12 hours, and stirred to obtain a uniform semiconductive synthetic rubber composition solvent solution.

Subsequently, the knitted fabric was dipped in a solution of the semiconductive synthetic rubber composition in an organic solvent to obtain a dry adhesion amount of 150 g.
/ M ² attached, heated in an oven kept at 110 ° C. for 5 minutes to volatilize and dry the solvent, and further heated in an oven kept at 170 ° C. for 5 minutes to give a semiconductive synthetic rubber composition. Is vulcanized and cut in the longitudinal direction with a width of 50 mm,
A semiconductive cushion tape of the present invention was obtained. The tape has a thickness of 1.0 mm and a unit mass of 475 g / m ² ,
The volume resistivity was 5.1 × 10 ⁴ Ω-cm.

Next, in order to investigate the absorption characteristics of the thermal expansion and contraction of the insulating core, a part of the tape was compressed to a thickness of 0.5 mm, sandwiched between glass plates, and placed in an oven maintained at a temperature of 70 ° C. After heating for an hour, allowing to cool to room temperature and leaving for 5 hours without compression, the thickness was 1.0 mm.
This heat cycle of 70 ° C. compression heating → room temperature uncompressed cooling was repeated 10 times. The thickness of the tape was 0.95 mm, which was almost unchanged and maintained almost the initial thickness.
This proves that the semi-conductive cushion tape of the present invention has excellent insulation core thermal expansion / contraction absorption.

[0036]

The semi-conductive cushion tape of the present invention has the following effects.

(1) Annular loop pile of multifilament yarn in which a knitted or woven fabric is intertwined with the ground structure (Wanna)
This tape has a three-dimensional mesh structure in the thickness direction, so when this tape is wound and installed between the insulating core and the metal sheath of a rubber / plastic power cable having a metal sheath, the tape is entangled in three dimensions. The mesh structure of the fibers sufficiently absorbs the thermal expansion and contraction of the insulating core and prevents the insulating core from being damaged such as scratches and dents.

(2) Since it does not require expensive calendering equipment or expensive continuous press vulcanization equipment for seating and pasting the semiconductive synthetic rubber composition required for the conventional production of the semiconductive cushion tape, it is versatile. It can be manufactured at high speed with the same equipment as the semi-conductive tape of, and the amount of the composition deposited per unit area is very small, so it is highly productive, inexpensive, and lightweight, contributing to the reduction of cable mass and price. .

(3) Besides a rubber / plastic power cable having a metal sheath, it can be used for fixing a copper wire / metal shield layer of a rubber / plastic insulated high-voltage power cable, and its practical value is extremely large.

[Brief description of drawings]

FIG. 1 is an example of a knitting structure diagram and a model cross-sectional view of a knitted fabric having an annular loop pile (ringna) of synthetic fiber multifilament yarns in a thickness direction used for a semiconductive cushion tape of the present invention.

FIG. 2 is a schematic view of a textured yarn that can be used to form an annular loop pile (inna) of synthetic fiber multifilament yarn in the thickness direction of the knitted fabric used for the semiconductive cushion tape of the present invention. .

FIG. 3 is a cross-sectional view of a rubber / plastic insulated power cable having a metal sheath using the semiconductive cushion tape of the present invention.

[Explanation of symbols]

 1 Synthetic fiber filament yarn annular loop pile 2 Ground yarn 3 Textured yarn A Insulating core 11 Conductor 12 Inner semiconductive layer 13 Insulating layer 14 Outer semiconductive layer 15 Semiconductive cushion tape winding layer 16 Copper wire weave half Conductive tape winding layer 17 Gap 18 Corrugated metal sheath 19 Anticorrosion layer

Claims (3)

[Claims] 1. A synthetic fiber multifilament yarn having an annular loop pile in the thickness direction, and having a thickness of 0.3 mm to 3.0.
A semiconductive cushion tape for a power cable, which is obtained by impregnating or applying a solvent solution of a semiconductive synthetic rubber composition to a knitted or woven fabric of mm, drying and vulcanizing. 2. The semiconductive cushion tape for a power cable according to claim 1, wherein the synthetic fiber multifilament yarn having a loop loop pile of knitted or woven fabric is a textured yarn. 3. The semiconductive cushion tape for a power cable according to claim 1, wherein the knitted fabric or the woven fabric is heat-set at a high temperature of 150 to 210 ° C. in advance.