JP5924381B2 - Twisted wire - Google Patents

Description

  The present invention relates to a twisted pair cable and a twisted pair cable for use in a high frequency region such as a LAN (Local Area Network) and a differential signal.

  The use of a stranded conductor is prohibited in the main part of the LAN cable (90 m section of the 100 m link length). The reason for this is that moisture (moisture) enters the gaps between the strands of the stranded conductor (hereinafter referred to as gap space) during long-term use, increasing the high-frequency resistance and leakage conductance, This is because the amount of attenuation is increased.

  On the other hand, because of the flexibility of stranded wire conductors for industrial applications, it is easy to lay and can be used for vibrating equipment, so it is used for applications with short link lengths, such as work LAN cables. ing. However, when used over a long distance over a long period of time, transmission loss increases, causing a failure due to a system error and a deterioration in data BER (Bit Error Rate).

  FIG. 7 shows a cross-sectional view of a twisted pair cable using a conventional twisted wire conductor used in applications where the link length used is short.

  This twisted pair cable 70 has seven strands 12 twisted in a 1/6 configuration (a configuration in which a single strand 12 arranged in the center is surrounded by six strands 12 spirally twisted). The twisted wire conductor 13 is included, the twisted wire conductor 13 is covered with the covering 33 to form the covered strand 72, and the twisted pair wire 71 obtained by twisting the covered strand 72 is further covered with the collective covering 16. It is formed by coating.

Japanese Patent Laid-Open No. 2001-6542

  As a condition for enabling the production of a stranded wire conductor, it is necessary to twist the strand. Without twisting, a wire conductor assembly is formed, and when wound on a bobbin, the wires cannot be entangled with each other.

  As shown in FIG. 8, the stranded conductor formed by twisting the strands (element diameter d) at a twist angle A is formed by connecting the strands at a pitch of an interval L = d / cosA in the length direction of the strand conductors. There will be a contact surface. Therefore, the equivalent volume resistivity (high frequency resistance) as a stranded wire conductor is not the conductor itself, but a volume resistivity constituted by the contact surface between the conductor (main part) and the strands and the gap space between them.

Here, the relationship among the attenuation (α), the resistance attenuation (α _R ), the leakage attenuation (α _g ), the equivalent volume resistivity (ρ), and the dielectric loss tangent tan δ in the stranded conductor is expressed by the following equations (1) to ( Shown in 3). However, the equivalent skin thickness t through which the high-frequency current propagates, the stranded conductor diameter D, the frequency f, the characteristic impedance Z _{c of} the pair, the mutual capacitance C of the pair, and the leakage conductance G = 2πfCtan δ.
α = α _R + α _g (1)
α _R = 2ρ / (πDt) / (2Z _c ) (2)
α _g = GZ _c / 2 (3)

  If a stranded conductor is used for a long period of time, moisture enters the gaps between the strands and the metal is corroded. For this reason, the unevenness | corrugation by corrosion is formed in the surface of a strand, and strands come to contact by a point instead of a surface. As a result, the contact resistance increases from 1.3 times to several times. Further, when the twist angle A is small, the interval L is also small, and the frequency of the gap space in the longitudinal direction of the stranded wire conductor (frequency with which the strands are in contact with each other) is increased. The volume resistivity ρ (high frequency resistance) increases by a factor of ten. This increases the resistance attenuation amount of the attenuation amount, and becomes a main cause of failure. In addition, when the moisture in the gap space increases, the gap electric field is included in the electric field between the conductors, causing deterioration of tan δ (deterioration of leakage conductance G), increasing the leakage attenuation amount of the attenuation amount, It becomes a secondary cause.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to reduce an increase in attenuation due to moisture in a twisted pair cable and a twisted pair cable using a twisted wire conductor.

  The present invention, which was created to achieve the above object, is a twisted twisted wire formed by coating a twisted wire conductor with a covering, and used as a high frequency transmission cable having a frequency of 100 MHz or more. In the wire, the coated strand is a twisted pair formed by coating a stranded conductor coated with a silane coupling agent with a covering made of polyethylene.

  The silane coupling agent may be present in a state in which the stranded conductor and the covering are bonded to each other by silane bonding or silanol bonding with moisture entering between the stranded conductor and the covering.

  ADVANTAGE OF THE INVENTION According to this invention, the increase in the attenuation amount by moisture can be reduced in the twisted pair cable and twisted pair cable using a twisted wire conductor.

It is sectional drawing which shows the structure of the twisted pair cable which concerns on 1st embodiment of this invention. It is sectional drawing which shows the structure of the twisted pair cable which concerns on 2nd embodiment of this invention. It is sectional drawing which shows the structure of the twisted pair cable which concerns on 3rd embodiment of this invention. It is a graph which shows the change of the attenuation amount before and behind an accelerated deterioration test of this invention and the conventional twisted pair cable. It is a graph which shows the change of the resistance attenuation amount and leakage attenuation amount before and behind an accelerated deterioration test of this invention and the conventional twisted pair cable. It is a graph which shows the compounding ratio of a vinyl silane coupling agent, the drawing-out force of a covering strand, and the relationship of the tensile breaking elongation of a coating body. It is sectional drawing which shows the structure of the conventional twisted pair cable. It is a schematic diagram explaining the relationship between the twist angle A and the pitch L of a strand wire conductor.

  The present inventors blend several mass% of the silane coupling agent into the coated body, or apply the silane coupling agent to the surface of the stranded conductor and then coat with the coated body to form a coated strand. The hydride polymer group (cover) and a metal such as copper (stranded conductor) are silane-bonded or silanol-bonded with moisture passing through the cover, blocking further moisture ingress, It has been found that the corrosion of the metal surface can be prevented and the equivalent volume resistivity can be prevented from increasing. At the same time, since the humidity of the gap space is not increased, tan δ is not increased. As a result, it has been found that an increase in resistance attenuation and leakage attenuation can be prevented, and the present invention has been achieved.

  That is, the present invention relates to a twisted wire formed by coating a twisted wire conductor with a covering, and in a twisted pair, a covering that covers the twisted wire conductor is coated with a silane coupling agent. A stranded conductor formed of a body material or coated with a silane coupling agent is covered with a covering.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the structure of a twisted pair cable using the twisted pair according to the first embodiment.

  As shown in FIG. 1, the twisted wire conductor 13 which twisted together the seven strands 12 by 1/6 structure is used for the twisted pair wire 11 which concerns on this Embodiment, and this strand wire conductor 13 is covered. The coated strand 15 formed by coating with 14 is twisted in pairs.

  For the wire 12, a normal good conductor such as pure copper or a copper alloy, or pure aluminum or an aluminum alloy can be used. Although the dimension of the strand 12 is not specifically limited, As an example, a thing of about φ0.2 mm can be used.

  In addition, the number of constituent wires 12 and the twist angle of the stranded wire conductor 13 are not particularly limited, and can be changed according to the usage environment (vibration, bending, etc.) of the paired stranded wire 11.

  The covering 14 is formed of a covering material obtained by blending a normal insulating resin with a silane coupling agent.

  As the insulating resin used for the covering material, for example, polyethylene (ultra low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, etc.) can be used.

  Examples of the silane coupling agent used for the covering material include vinyl silane, acryloxy silane, mercapto silane, amino silane, and epoxy silane.

  The compounding ratio of the silane coupling agent in the covering material is preferably 0.5% by mass or more and 2.0% by mass or less. In consideration of the bond with the stranded conductor, a blending ratio of 0.5% by mass is sufficient. When the blending ratio is less than 0.5% by mass, the bond with the stranded conductor is insufficient, the effect of blocking the entry of moisture (water) described later is insufficient, and the increase in attenuation is suppressed. I can't. On the other hand, if the blending ratio exceeds 2.0% by mass, the plasticity (tensile properties, etc.) of the coated body is impaired, and excessive compounding agent migration occurs, making it unsuitable for insulation coating. Become.

  The paired twisted cable 10 is formed by using at least one paired twisted wire 11 and jacketing with the collective covering 16.

  When flame-retarding a twisted pair cable, a batch covering containing a flame retardant in which a flame retardant such as magnesium hydroxide is blended with a sheath material made of polyvinyl chloride (PVC), for example, is used as the batch covering 16. Can do. This is because if a flame retardant made of a metal oxide is blended in the covering 14 that covers the stranded conductor 13, the tan δ of the metal oxide is poor, and the transmission loss of the twisted wire increases at a high frequency. In addition, this invention does not specifically limit the structure of the package body containing a flame retardant, A various sheath material and a flame retardant can be used and a flame retardance can be acquired, maintaining a high frequency characteristic.

  The twisted pair wire 11 or the twisted pair cable 10 having the above configuration is particularly effective for high frequency transmission of 100 MHz or higher.

  Next, the operation of the present embodiment will be described.

  In the twisted pair wire according to the present embodiment, the covering that covers the stranded conductor is formed of a covering material that contains a silane coupling agent. As a result, when moisture (humidity) enters between the stranded conductor and the covering, the stranded bond or silanol is bonded to the stranded conductor and the covering with the moisture to improve adhesion, It is possible to block the approach and suppress an increase in contact resistance due to metal corrosion.

  At the same time, deterioration of tan δ due to the ingress of moisture can be suppressed, and an increase in leakage resistance can be suppressed, so that it has sufficient moisture resistance.

  In addition, in the twisted pair cable according to the present embodiment, since a twisted pair cable having moisture resistance is used, an increase in attenuation can be suppressed even when moisture enters through a collective covering (sheath), so a desired amount These flame retardants can be added to the batch coating.

  Next, a second embodiment will be described with reference to FIG.

  In the present invention, the stranded conductor and the cover are bonded to each other by a silane coupling agent using a silane coupling agent or a silanol bond, thereby preventing moisture from entering the gap between the stranded conductor and the cover.

  Therefore, it is not necessary to mix a silane coupling agent over the entire thickness of the covering, and as shown in FIG. 2, the stranded wire conductor 13 is covered with two layers of coverings 14a and 14b to form the covering strands 22. Of these two layers of coverings 14a and 14b, the inner layer covering 14a in contact with the stranded conductor 13 may be formed of a covering material blended with a silane coupling agent. Thereby, the stranded wire conductor 13 and the inner layer covering 14a can be silane-bonded or silanol-bonded, and moisture resistance can be obtained.

  Also in the twisted pair wire 21 and the twisted pair cable 20, the same effects as those in the above embodiment can be obtained.

  Moreover, in this twisted pair wire 21, since only the inner layer covering 14a in contact with the stranded conductor 13 is formed of a covering material mixed with a silane coupling agent, the outer layer covering 14b has a silane coupling. There is no deterioration of the plasticity of the covering material by blending the agent, and the characteristics of the twisted pair wire 21 can be made better.

  As shown in FIG. 3, in the present invention, a silane coupling agent 32 is applied to the stranded conductor 13, and this is coated with a covering 33 (which does not contain a silane coupling agent) to coat the coated wire 34. You may make it form.

  In the twisted pair cable 31 and the twisted pair cable 30, the same effect as that of the above embodiment can be obtained only by applying the silane coupling agent 32 to the surface of the twisted conductor 13, and more easily. Can be manufactured.

  According to the present invention described above, a twisted wire conductor can be applied to a relatively long-distance industrial LAN cable, and a twisted pair wire that can be applied to high-frequency balanced (differential) signal transmission in a vehicle with large vibrations. Can do. The twisted pair wire and the twisted pair cable according to the present invention are particularly effective as a high frequency transmission cable of 100 MHz or higher.

  In addition, this invention is not limited to the said embodiment, A various change is possible.

  Examples of the present invention will be described below.

  The twisted pair cable according to the first embodiment of the present invention (FIG. 1: hereinafter referred to as a product of the present invention) and the conventional twisted cable (FIG. 7: referred to as a conventional product) are as follows. Made.

  Seven copper strands of φ0.208 mm were twisted at a twist angle of 75 degrees with a configuration of 1/6, and two of these were produced as a twisted wire conductor of φ0.565 mm.

  In the product of the present invention, a twisted wire conductor is extruded and coated using a coating material in which 1% by mass of a vinylsilane coupling agent is blended with low density polyethylene (hereinafter referred to as PE) for insulation coating, and a coated wire having a diameter of 0.97 mm is formed. Manufactured. On the other hand, in the conventional product, a twisted wire conductor was extruded and coated using PE to produce a coated strand of φ0.97 mm.

  Each of these coated strands was twisted with a constant twisting step to complete a twisted strand of φ1.94 mm. A PVC sheath was jacketed on the twisted pair wire to complete a 2.74 mm twisted pair cable.

  In order to demonstrate the effect of the invention, an accelerated deterioration test was performed on each manufactured twisted pair cable at 85 ° C., 85% relative humidity, for 30 days. This accelerated deterioration test condition is a condition that is generally applied to a communication apparatus and assumes an accelerated load of 25 to 30 years.

  FIG. 4 shows the result of measuring and comparing the initial attenuation of the product of the present invention and the conventional product and the attenuation after the accelerated deterioration test. The initial attenuation of the product of the present invention and the initial attenuation of the conventional product were the same.

  From FIG. 4, it can be seen that, as an effect of the present invention, an increase in attenuation after the accelerated deterioration test (corresponding to a life of 25-30 years) was suppressed. As a specific numerical value (raw data), the attenuation at a frequency of 100 MHz (initial: 21.5 dB / 100 m) is 21.9 dB / 100 m compared with 26.9 dB / 100 m (25% increase from the initial value) for the conventional product. It was proved that the deterioration could be sufficiently stopped (increase of 1.9% from the initial stage). This is considered to have proved that the silane coupling agent silane-bonded the coated body and copper and prevented moisture from entering the gap space.

  Next, the resistance attenuation amount and the leakage attenuation amount were evaluated from the respective attenuation amount curves obtained in FIG. 4 as follows.

The attenuation amount (α) is divided into a resistance attenuation amount (α _R ) and a leakage attenuation amount (α _g ) by the following equations (4) and (5).
α = α _R + α _g = A√f + Bf (4)
(However, α _R = A√f, α _g = Bf)
α / √f = A + B√f (5)

  Therefore, by calculating equation (5), the A term is obtained as the resistance attenuation term and the B term is obtained as the leakage attenuation term.

  As shown in FIG. 4, the attenuation (α) is in the transition region up to 56 MHz, and linear interpolation of equation (5) is not possible. Therefore, equation (5) is calculated with data of 56 MHz or higher, and data from 56 MHz to 225 MHz is linear. Interpolated and calculated interpolation formula. The result is shown in FIG.

Further, the attenuation amount (α), the resistance attenuation amount (α _R ), and the leakage attenuation amount (α _g ) at the frequency f = 100 MHz were obtained from the interpolation formula shown in FIG. These numerical values are shown in Table 1.

  Here, how to obtain these numerical values will be described below.

  Equation (5) corresponds to the interpolation equation shown in FIG. That is, α / √f = y = A + B√f, where A is a constant term in the interpolation formula, B is a proportional coefficient of x in the interpolation formula, and √f is x. Each numerical value shown in Table 1 can be obtained from these relationships and Equation (4).

5 and Table 1, at a frequency of 100 MHz, the resistance attenuation amount (α _R ) of the product of the present invention suppresses the 121% degradation of the conventional product to 101%, and the leakage attenuation amount (α _g ) is the conventional product. It was proved that 226% degradation in the case can be suppressed to 133%.

  Next, in the product of the present invention, the blending ratio of the vinyl silane coupling agent of the covering material is changed from 0 to 2.5% by mass to prepare a coated strand, and the blending ratio of the silane coupling agent to the covering material Of the copper conductor / covering body and the influence on the tensile elongation at break of the covering body were evaluated. The pulling force of the copper conductor / covering body indicates the degree of silane bonding and silanol bonding between the stranded conductor and the covering body.

  FIG. 6 shows the results of testing the pulling force of the copper conductor / covering body having a length of 50 mm and the tensile breaking elongation of the covering body itself.

  From FIG. 6, it can be seen that even when the blending ratio of the silane coupling agent is 0.5% by mass, the same effect as that when the blending ratio is 1.0% by mass is obtained. This is because a combination of 0.5% by mass with copper is sufficient. On the other hand, if it exceeds 2.0%, it is understood that the plasticity of the coated body is impaired, and that an excessive compounding agent is transferred and is not suitable for insulating coating.

  Based on the above data, the compounding ratio of 1% at which the pulling force of the conductor / covering body is almost saturated and the compounding ratio of 1% in the region where the tensile elongation at break of the covering body does not deteriorate suddenly become the optimum mixing ratio. I understood it.

DESCRIPTION OF SYMBOLS 10 Pair twisted cable 11 Pair twisted wire 13 Stranded wire conductor 14 Covering body 15 Covering strand

Claims (2)

In the twisted pair wire used as a high frequency transmission cable having a frequency of 100 MHz or more, which is formed by twisting a covered strand formed by coating a twisted wire conductor with a covering,
Before Symbol coating wire becomes a stranded conductor coated with a silane coupling agent is formed by coating with a coating material consisting of polyethylene,
A twisted pair wire formed by twisting a coated strand formed by coating a twisted wire conductor to which the silane coupling agent is applied and a twisted wire conductor not coated with the silane coupling agent with a coating made of polyethylene. In contrast, after the accelerated deterioration test, and after the accelerated deterioration test performed under the conditions of 85 ° C., 85% relative humidity and 30 days, respectively, the attenuation amount at a frequency of 100 MHz, the resistance attenuation amount, and the leakage attenuation amount were measured. When calculating the rate of change in attenuation before and after the accelerated deterioration test, the rate of change in resistance attenuation, and the rate of change in leakage attenuation,
Any of the rate of change in the amount of attenuation of the twisted pair wire to which the silane coupling agent is applied, the rate of change in resistance attenuation, and the rate of change in leakage attenuation are not found in the twisted pair wire to which the silane coupling agent is applied. A twisted pair wire that is smaller than the rate of change in attenuation, the rate of change in resistance attenuation, and the rate of change in leakage attenuation .   2. The silane coupling agent is present in a state in which the stranded conductor and the cover are silane-bonded or silanol-bonded with moisture entering between the stranded conductor and the cover. The twisted pair wire described in 1.

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