JPWO2020032143A1 - Insulated wire - Google Patents

Abstract

The total residual amount of the volatile organic compound and the quasi-volatile organic compound having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the insulating layer is 1500 ppm or less. In particular, when the insulating layer contains organopolysiloxane, the small molecule cyclic siloxanes D4 to D10 are reduced. Further, in the case of an insulated wire in which at least two insulating layers including a first insulating layer and a second insulating layer are coated around the conductor, the boiling point remaining in all the insulating layers is in the range of 150 ° C. to 360 ° C. The total residual amount of the volatile organic compound and the semi-volatile organic compound in the above is 1500 ppm or less.

Description

The present invention relates to an insulated wire, and is particularly suitable for a high voltage power cable used in an automobile.

Insulated electric wires used in vehicles such as automobiles are required to have various characteristics such as mechanical characteristics, flame retardancy, heat resistance, and cold resistance, and one of the required characteristics is smoke emission characteristics.

Recently, electric vehicles that use electric motor drive and hybrid vehicles that use both motor drive and conventional gasoline engine drive have appeared. An automobile using such a motor drive needs to supply a high voltage and a large current for the motor drive.
Insulated wires that supply high voltage and large current tend to reach high temperatures, and the smoke generation characteristics of insulated wires in a high temperature environment generally deteriorate.

One of the methods to improve the smoke generation characteristics is to increase the conductor cross-sectional area of the insulated wire and reduce the heat generation when energized. However, the insulated wire that supplies high voltage and large current has a large conductor cross-sectional area from the beginning. It is often designed, and further increase in conductor cross-sectional area leads to enlargement of the insulated wire, it is difficult to secure a space for arranging the insulated wire, and there are problems such as deterioration of fuel efficiency due to an increase in weight.

As a method for reducing the amount of smoke generated during combustion, a method in which halogen is not used as the insulating material used for the insulated electric wire (Patent Document 1) or a method obtained by polymerizing tetrafluoroethylene and an α-olefin having 2 to 4 carbon atoms is obtained. A method of using a fluoroelastomer composition containing a base polymer containing a tetrafluoroethylene-α-olefin copolymer (Patent Document 2) is known.

However, these methods are intended to reduce the amount of smoke generated in an emergency situation such as when an insulated wire is burned, and do not necessarily contribute to the improvement of smoke generation characteristics, which has a strong meaning as a safety index before combustion. ..

Further, as shown in FIG. 2, when there are a plurality of insulating layers, the smoke emitting characteristics tend to be deteriorated as compared with an insulated wire having only one insulating layer.

As shown in FIG. 4, some of the high-voltage power cables for automobiles are provided with a shield layer on the outer periphery of the first insulating layer and further provided with a second insulating layer. Improvement of smoke generation characteristics is also required for high-voltage power cables of such a mode.

Japanese Unexamined Patent Publication No. 2000-191845 Japanese Unexamined Patent Publication No. 2017-33784

An object of the present invention is to provide an insulated wire having improved smoke emitting characteristics without increasing the cross-sectional area of the conductor. Another object of the present invention is to provide an insulated electric wire having excellent smoke emitting characteristics even in a mode having a plurality of insulating layers.

As a result of detailed analysis of the smoke generation mechanism of the insulated wire, the present inventor has reduced the volatile components contained in the insulating layer and the behavior of the volatile organic compounds during the reduction treatment of the volatile organic compounds. By paying attention to the above and suppressing the phenomenon of re-adsorption to the insulating layer on the inner peripheral side, the conventional problem has been solved.

The present invention is an insulated wire in which an insulating layer is coated around a conductor, and the total residual amount of volatile organic compounds and quasi-volatile organic compounds having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the insulating layer is It is characterized by being 1500 ppm or less.

Further, the present invention is an insulated wire in which at least two insulating layers including a first insulating layer and a second insulating layer are coated around a conductor, and the boiling points remaining in all the insulating layers are 150 ° C. to 360 ° C. The total residual amount of the volatile organic compound and the quasi-volatile organic compound in the range of is 1500 ppm or less.

According to the present invention, the smoke emitting characteristics can be improved without increasing the cross-sectional area of the conductor, and good smoke emitting characteristics can be obtained even with an insulated wire having a plurality of insulating layers.

It is a figure which shows the basic structure of the insulated wire of this invention. It is an example of the insulated wire of this invention, and is the figure which shows the aspect which has a plurality of insulating layers. It is an example of the insulated wire of this invention, and is the figure which shows the aspect which has the transmission | transmission suppression layer. It is an example of the insulated wire of this invention, and is the figure which shows the aspect which has a shield layer. It is an example of the insulated wire of this invention, and is the figure which shows the aspect which has a transmission suppression layer and a shield layer.

Hereinafter, the basic configuration of the present invention will be described with reference to the accompanying drawings. In FIG. 1, 1 is an insulated wire of the present invention, 10 is a conductor, and 12 is an insulating layer. The configuration of the present invention is not limited to FIG. 1, and can be changed within the scope of the idea of the present invention.
What is characteristic of the present invention is that the total residual amount of the volatile organic compound and the quasi-volatile organic compound in which the boiling point remaining in the insulating layer 12 is in the range of 150 ° C. to 360 ° C. is 1500 ppm or less. be.

Volatile organic compounds (VOCs) are a general term for organic compounds that exist in the atmosphere as a gas and have a boiling point of about 50 to 260 ° C. Semi-volatile organic compounds (SVOCs) are organic compounds that exist in the atmosphere as a gas. It is a general term for those having a boiling point of about 260 to 400 ° C.
Hereinafter, unless otherwise specified, "VOC" is used as a term referring to both volatile organic compounds and semi-volatile organic compounds.

The smoke emitting characteristics of the insulated wire 1 are measured by the test described in the Japanese Automotive Standards Organization JASO D609. Specifically, an insulated wire 1 having a certain length is prepared as a sample and maintained horizontally in an environment set to a test temperature. Various types of direct current are passed through the sample by changing the current value, and the time until smoke is confirmed is measured. Several types of test temperatures are set, the relationship between the current value and the smoke emission start time is obtained for each test temperature, and the result is treated as the smoke emission characteristic of the insulated wire 1.

In the smoke generation characteristic test, a current is passed through the insulated wire 1 placed in a high temperature environment, the insulating layer 12 deteriorates due to heat generated by the high temperature and energization, and the deteriorated material of the insulating layer 12 evaporates as visible smoke. It is generated by scattering.

However, when the VOC remains in the insulating layer 12, the VOC starts to evaporate and scatter before reaching the heat resistant temperature of the insulating layer 12 and the short-time allowable temperature of the insulated wire 1, and the scattered VOC is visible. Since it becomes smoke, even if the insulating electric wire 1 and the insulating layer 12 have high heat resistance, there are situations where the smoke emitting characteristics deteriorate.

Therefore, by reducing the VOC remaining in the insulating layer 12, smoke generation derived from VOC is reduced, so that smoke generation characteristics corresponding to the heat resistance inherent in the insulating layer 12 can be obtained, and as a result, smoke generation of the insulating wire 1 can be obtained. The characteristics are improved.

Insulated electric wires 1 that are generally required to have smoke emitting characteristics are often required to have heat resistance, and the smoke emitting characteristics (smoke temperature) of an electric wire having a heat resistant temperature of about 150 to 200 ° C. are sufficiently higher than the heat resistant temperature. Is often required. Therefore, by reducing the VOC having a boiling point of 150 ° C. or higher, the smoke generation characteristics of the insulated wire 1 can be effectively improved.

Specifically, by setting the residual amount of VOCs having a boiling point in the range of 150 ° C. to 360 ° C. to 1500 ppm or less, most of the VOCs that cause smoke generated in the smoke emission characteristic test are removed, so that the smoke emission characteristics Is improved.

Since the smoke emission characteristics tend to improve as the residual amount of VOC decreases, it is more preferable that the residual amount of VOC having a boiling point in the range of 150 ° C. to 360 ° C. is 1000 ppm or less.

The present invention can be particularly preferably used when the material constituting the insulating layer 12 contains an organopolysiloxane.

As a typical example of an insulating material containing an organopolysiloxane, silicone rubber having excellent flexibility, insulating property, heat resistance, cold resistance and the like is known. Usually, silicone rubber is used by blending and kneading a vulcanizing agent, a pigment, etc. with a silicone rubber compound, heating and vulcanizing the silicone rubber under predetermined conditions, and then curing the silicone rubber.

The silicone rubber compound contains dimethylpolysiloxane obtained by ring-opening polymerization of cyclic dimethylsiloxane tetramer (D4) as a main component. However, since this ring-opening polymerization reaction is a reversible reaction, the silicone rubber compound So-called low molecular weight cyclic siloxane remains inside.

That is, when the material constituting the insulating layer 12 contains an organopolysiloxane, the small molecule cyclic siloxane remains in the insulating layer 12. The small molecule cyclic siloxane is a type of VOC and is one of the factors that lower the smoke generation characteristics of the insulated wire 1.

Generally, cyclic dimethylsiloxane trimers (D3) to cyclic dimethylsiloxane dequotes (D10) are treated as small molecule cyclic siloxanes. In cyclic dimethylsiloxane, the boiling point of D3 is 134 ° C. under atmospheric pressure, the boiling point of D4 is 175 ° C. under atmospheric pressure, and the boiling point increases as the molecular weight increases, such as D5, D6 ... It is estimated to be about 360 ° C under atmospheric pressure. Since the boiling point of D3 is relatively small, most of it evaporates in the manufacturing process of the insulated wire 1, and the residual amount is small, but the residual amount of D4 to D10 is larger than that of D3.

The small molecule cyclic siloxane, which is one of the factors that lower the smoke generation characteristics of the insulated wire 1, is not limited to the cyclic dimethylsiloxane. Examples of the organic substituent bonded to the silicon atom of the siloxane bond include not only a methyl group but also an ethyl group, a vinyl group, a phenyl group and the like, and a combination thereof is also arbitrary.
In addition to the small molecule cyclic siloxane, sublimable substances such as benzoic acid and derivatives of benzoic acid can be mentioned as factors that lower the smoke generation characteristics of the insulated wire 1.

Therefore, in the insulated wire 1 using the insulating layer 12 containing the organopolysiloxane, the total residual amount of the small molecule cyclic siloxanes D4 to D10, which are VOCs having a boiling point in the range of 150 ° C. to 360 ° C., is 1500 ppm or less. Therefore, the smoke generation characteristics of the insulated wire 1 can be improved.

As the material of the insulating layer 12 containing the organopolysiloxane, various silicone rubbers, a mixture of silicone rubber and other materials, and the like can be used.

When the insulating layer 12 is a mixture of silicone rubber and other materials, as the mixing ratio of silicone rubber increases, the residual amount of low-molecular-weight cyclic siloxane tends to increase and the smoking characteristics tend to deteriorate. Even if the ratio is high, the smoke generation characteristics can be improved by setting the total residual amount of low molecular weight cyclic siloxane in the range of 150 ° C. to 360 ° C. to 1500 ppm or less.

Originally, even in the insulating layer 12 composed of a single silicone rubber in which a particularly large amount of low-molecular-weight cyclic siloxane remains, the total residual amount of low-molecular-weight cyclic siloxane having a boiling point in the range of 150 ° C. to 360 ° C. is set to 1500 ppm or less. As a result, the smoke generation characteristics can be improved, so that the effect is particularly high when the insulating layer 12 is a single silicone rubber.

When the insulating electric wire 1 is constructed by using the insulating layer 12 containing the organopolysiloxane, the residual amount of at least one of the small molecule cyclic siloxanes D4 to D6 remaining in the insulating layer 12 is preferably 1000 ppm or less. ..

The small molecule cyclic siloxanes D4 to D6 belong to volatile organic compounds and have a high vapor pressure despite their high boiling points, so they tend to volatilize relatively easily even at room temperature and occupy most of the VOC remaining in the insulating layer 12. be. Smoke emission characteristics are improved by setting the residual amount of at least one of the small molecule cyclic siloxanes of D4 to D6 having such properties to 1000 ppm or less.

The effect of improving smoke emission characteristics can be obtained by setting the residual amount of at least one of the small molecule cyclic siloxanes D4 to D6 to 1000 ppm, but from the viewpoint of keeping the total residual amount of the small molecule cyclic siloxane to 1500 ppm or less, D6 The residual amount is preferably 100 ppm or less. More preferably, the total residual amount of the small molecule cyclic siloxanes D4 to D6 is 100 ppm or less.

Of the small molecule cyclic siloxanes D4 to D6, D6 tends to remain in the insulating layer 12 in a relatively large amount. Therefore, by intensively reducing the residual amount of D6, the smoke emission characteristics can be effectively improved. can. Further, as the residual amount of D6 is reduced, the residual amount of D4 and D5 tends to be reduced, and by setting the total residual amount of the small molecule cyclic siloxanes of D4 to D6 to 100 ppm or less, the smoke emitting characteristics are further improved. It will be improved.

When the insulating electric wire 1 is constructed by using the insulating layer 12 containing the organopolysiloxane, the total residual amount of the small molecule cyclic siloxanes D4 to D8 should be 500 ppm or less in consideration of the design in a practical range. Suitable.

In addition to the small molecule cyclic siloxanes D4 to D6, the VOCs are particularly prone to visible smoke in the D7 and D8 smoke emission characteristic tests, so the residual amount of D8 is intensively reduced, and the residual amount of D7 accompanies this. By reducing the amount, the smoke generation characteristics of the insulated wire 1 can be improved more effectively.
Desirably, the residual amount of the small molecule cyclic siloxane of D8 is preferably 300 ppm or less.

When the insulating electric wire 1 is constructed by using the insulating layer 12 containing the organopolysiloxane, it is more preferable that the total residual amount of the small molecule cyclic siloxanes D4 to D10 is 400 ppm or less.

The small molecule cyclic siloxanes of D9 and D10 tend to evaporate at around 300 ° C, which is the short-term allowable temperature of general silicone rubber-coated insulated wires defined by JCS (Japan Electric Wire Manufacturers Association) Standard No. 168, and in the high temperature range. Affects the smoke characteristics of. Considering the residual amount of D9 and D10, the total residual amount of the small molecule cyclic siloxane of D10 is set to 200 ppm or less, and the residual amount of D9 is also reduced accordingly, so that the smoke generation temperature of the insulated wire 1 is coated with silicone rubber. The short-term allowable temperature of the insulated wire can be approached, and the smoke generation characteristics can be further improved.
Desirably, the total residual amount of the small molecule cyclic siloxanes of D9 and D10 is preferably 300 ppm or less.

Examples of the method for reducing the residual amount of VOC remaining in the insulating layer 12 include the following methods.

(Method 1) The insulated wire 1 is heated at a predetermined temperature and time to forcibly evaporate the VOC in the insulating layer 12.

(Method 2) The insulated wire 1 is immersed in a solvent, and the VOC in the insulating layer 12 is eluted in the solvent.

(Method 3) A low VOC type insulating material is used for the insulating layer 12.

(Method 4) A material formed by mixing a material mainly composed of organopolysiloxane and a low VOC type insulating material is used for the insulating layer 12.

Of the methods described above, method 1 can be used most preferably. Method 1 is a method that can be used regardless of the type of insulating material, and can be performed by using a heating means such as a heating furnace that is industrially easy to handle.

Further, since the insulated wire 1 of the present invention may contain a substance having a property of evaporating and scattering due to a temperature rise in addition to the VOC, the residual amount of the substance other than the VOC is required to improve the smoke generation characteristics. It is also preferable to reduce.

Examples of substances other than VOCs that have the property of evaporating and scattering due to temperature rise include sublimable substances. Since the sublimable substance changes its state from a solid to a gas directly as the temperature rises, it easily evaporates and scatters, and causes visible smoke like VOC.

Examples of the sublimable substance that is likely to be contained in the insulating layer 12 in the insulated wire 1 as in the present invention include benzoic acid (boiling point: about 249 ° C.) and its derivative.

Benzoic acid and its derivatives are generated as decomposition products of organic peroxides used as reaction initiators when forming an insulating layer 12 made of silicone rubber using peroxide vulcanization having an excellent cross-linking rate. It is contained in the insulating layer 12. Examples of the main derivative include 2,4-dichlorobenzoic acid (boiling point: about 200 ° C.) and 4-methylbenzoic acid (boiling point: about 274 ° C.).

Benzoic acid and its derivatives have a boiling point equivalent to that of VOCs, and start sublimation at a temperature lower than the boiling point. Therefore, they are contained in the smoke generated in the smoke characteristic test and act in a direction of deteriorating the smoke characteristic.

Similar to VOC, by reducing the sublimable substance remaining in the insulating layer 12, the smoke generated from the sublimated substance is reduced, so that the smoke emitting characteristics according to the heat resistance inherent in the insulating layer 12 can be obtained, and as a result. As a result, the smoke generation characteristics of the insulated wire 1 are improved.

Normally, the residual amount of the sublimable substance remaining in the insulating layer 12 is smaller than the residual amount of VOC, and the total residual amount of VOC having a boiling point remaining in the insulating layer 12 in the range of 150 ° C. to 360 ° C. When the sum of the total residual amounts of the sublimable substances remaining in the insulating layer 12 is 1500 ppm or less, good smoke emitting characteristics can be obtained.

More preferably, the total residual amount of the sublimating substance remaining in the insulating layer 12 is 300 ppm or less.

Examples of the method for reducing the residual amount of the sublimable substance remaining in the insulating layer 12 include the following methods.

(Method 1) The insulating electric wire 1 is heated at a predetermined temperature and time to forcibly evaporate the sublimable substance in the insulating layer 12.

(Method 2) The insulating electric wire 1 is immersed in a solvent, and the sublimable substance in the insulating layer 12 is eluted in the solvent.

(Method 3) When the insulating layer 12 is made of silicone rubber, the insulating layer 12 made of silicone rubber is formed by using a vulcanization method (additional vulcanization or the like) that does not use an organic peroxide.

In addition, an embodiment having a plurality of insulating layers in the present invention will be described with reference to the accompanying drawings. In FIGS. 2 to 5, 2 to 5 are insulated wires of the present invention, 20 is a conductor, and 22 is an insulating layer. Of the insulating layers 22, 23 located on the inner peripheral side of the insulated wires 2 to 5 is the first insulating layer, and 24 located on the outer peripheral side of the first insulating layer 23 is the second insulating layer. The configuration of the present invention is not limited to FIGS. 2 to 5, and can be changed within the scope of the idea of the present invention. Although FIGS. 2 to 5 show the first insulating layer 23 and the second insulating layer 24 as at least two insulating layers 22, an insulating layer may be further provided.
Each of the first insulating layer 23 and the second insulating layer 24 may have uniform physical properties in each layer, or may have physical properties that change in the wall thickness direction and / or the length direction of the insulated wire.

What is characteristic of the present invention is that the insulated wires 2 to 5 cover the conductor 20 with at least two insulating layers 22 including the first insulating layer 23 and the second insulating layer 24, and the first insulation is provided. Volatile organic compounds and quasi-volatile compounds having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the layer 23 and the second insulating layer 24, and in the case of including the insulating layer, all the insulating layers 22 including those insulating layers. The total residual amount of the sex organic compounds is 1500 ppm or less. That is, the total residual amount of VOCs having a boiling point remaining in the first insulating layer 23 in the range of 150 ° C. to 360 ° C. and the remaining VOCs having a boiling point remaining in the second insulating layer 24 in the range of 150 ° C. to 360 ° C. The sum of the total amount and the total residual amount of each VOC whose boiling point remains in the range of 150 ° C. to 360 ° C. when the third insulating layer and the fourth insulating layer are included is 1500 ppm or less. That is.

By setting the sum of the residual amounts of VOCs having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the first insulating layer 23 and the second insulating layer 24 to 1500 ppm or less, the smoke generated in the smoke generation characteristic test can be used. Since most of the causative VOCs are removed, the smoke emission characteristics are improved.

Since the smoke emitting characteristics tend to improve as the residual amount of VOC decreases, the boiling point remaining in each of the first insulating layer 23 and the second insulating layer 24 tends to be in the range of 150 ° C. to 360 ° C. The sum of the residual amounts of a certain VOC should be 1000 ppm or less.

Further, in the present invention, as shown in FIG. 3, low permeability is provided between the first insulating layer 23 and the second insulating layer 24 for VOCs having a boiling point in the range of 150 ° C. to 360 ° C. It is preferable to provide the permeation suppressing layer 26 as shown.

When the VOC is reduced by using the above method 1 or 2 for the insulated wire 2 having two insulating layers, the VOC contained in the second insulating layer 24, which is the outermost layer, is reduced, but inside. It takes time for the VOC contained in the located first insulating layer 23 to be sufficiently reduced due to the presence of the second insulating layer 24 as an obstacle.

The above problem can be solved by providing the second insulating layer 24 after the first insulating layer 23 has been subjected to the VOC reduction treatment in advance. In this case, when the second insulating layer 24 is subjected to the VOC reduction treatment. In some cases, a part of the VOCs desorbed from the second insulating layer 24 is re-adsorbed to the first insulating layer 23, and the total amount of VOCs contained in the insulated wire 2 is not significantly reduced.

As shown in FIG. 3, the second insulating layer 24 is included by providing the permeation suppressing layer 26, which exhibits low permeability to VOC, between the first insulating layer 23 and the second insulating layer 24. The phenomenon that the VOCs have been re-adsorbed to the first insulating layer 23 is suppressed, which contributes to a reduction in the total amount of VOCs contained in the insulated wire 3.

The permeation suppressing layer 26 is selected from materials having low permeability to VOC contained in the insulating layer and suppressing VOC adsorption as much as possible, and various metal materials, polyethylene, PET (polyethylene terephthalate), and the like. Fluorine and the like can be preferably used.
From the viewpoint of suppressing the permeation of VOC, a crystalline material having a high barrier property to gas is particularly preferable, and PET in which a large number of crystalline regions are easily formed due to the molecular structure and a metal material for forming a metal crystal are used. Among the metal materials, copper and aluminum, which form a dense oxide film having a barrier property against gas, are particularly preferable.

As an example of how to provide the permeation suppressing layer 26, there is an embodiment in which a tape-shaped member such as a metal foil tape, a resin tape, or a metal-deposited resin tape is wound around the first insulating layer 23. As the winding method, the winding method used for electric wires / cables in which the tape is wound, such as horizontal winding or vertical attachment, may be appropriately selected.

When the tape-shaped member is wound around the first insulating layer 23 to provide the permeation suppressing layer 26, it is preferable to wind the tape-shaped member so as to wrap it with 1/6 wrap or more. By wrapping with 1/6 wrap or more, the generation of gaps in the wrap portion is suppressed, and the permeation suppressing function for VOC is improved. More preferably, it is wrapped with 1/4 wrap or more.

When a tape-shaped member is used as the permeation suppressing layer 26, it is preferable to use a member made of a solid material from the viewpoint of ensuring low permeability to VOC, but a range in which low permeability to VOC can be maintained. In, a porous material may be used.

When a tape-shaped member is used as the permeation suppressing layer 26, the thickness of the member is not particularly limited. A thick one is preferable from the viewpoint of ensuring low permeability to VOC, but a thin one may be used if low permeability is ensured by material selection, and a thin one is preferable from the viewpoint of suppressing the outer diameter of the insulated wire 3.

The members and modes used as the permeation suppressing layer 26 are not limited to those described above, and various members, materials, and modes can be selected and used within the scope of the technical idea of the present invention.
For example, a mode in which a coating layer exhibiting low permeability to VOC is provided, such as providing metal vapor deposition on the outer periphery of the first insulating layer 23, or a gap existing in the shield layer 28 of FIG. 5, which will be described later, is provided with respect to VOC. An embodiment in which the permeation suppressing layer 26 and the shield layer 28 are combined by filling with a material exhibiting low permeability can be mentioned.

The present invention is intended for use in high-voltage power cables for automobiles, but some insulated wires for this purpose have a shield layer 28 as shown in FIG. 4, and insulation in this aspect is provided. The electric wire 4 usually has a first insulating layer 23 and a second insulating layer 24.
The present invention can be particularly suitably used for improving the smoke generation characteristics of the insulated wire 4 having the shield layer 28 as shown in FIG.

When the insulation wire 5 of the present invention is formed by providing both the transmission suppression layer 26 and the shield layer 28, the mode in which the transmission suppression layer 26 is provided between the shield layer 28 and the second insulation layer 24 (FIG. 5), or An embodiment in which a permeation suppressing layer is provided between the first insulating layer and the shield layer (not shown) can be appropriately selected and used.

Further, the insulated wires 2 to 5 of the present invention can be particularly preferably used when the material constituting at least one of the first insulating layer 23 and the second insulating layer 24 contains an organopolysiloxane.

D4, which is a VOC having a boiling point in the range of 150 ° C. to 360 ° C. remaining in each of the first insulating layer 23 and the second insulating layer 24 in the insulated wires 2 to 5 using the insulating layer containing the organopolysiloxane. By setting the sum of the residual amounts of the small molecule cyclic siloxanes of ~ D10 to 1500 ppm or less, the smoke generation characteristics of the insulated wires 2 to 5 can be improved.

When the insulating layer 22 is a mixture of silicone rubber and other materials, as the mixing ratio of silicone rubber increases, the residual amount of low molecular weight cyclic siloxane tends to increase and the smoking characteristics tend to deteriorate. Even if the ratio is high, the sum of the residual amounts of low molecular weight cyclic siloxanes having boiling points remaining in the first insulating layer 23 and the second insulating layer 24 in the range of 150 ° C. to 360 ° C. is 1500 ppm or less. By doing so, the smoke generation characteristics can be improved.

Originally, even in an insulating layer composed of a single silicone rubber in which a particularly large amount of low molecular weight cyclic siloxane remains, the boiling point remaining in each of the first insulating layer 23 and the second insulating layer 24 is in the range of 150 ° C. to 360 ° C. By setting the sum of the residual amounts of the low molecular weight cyclic siloxanes in the above to 1500 ppm or less, the smoke generation characteristics can be improved, so that the effect is particularly high when the insulating layer 22 is a single silicone rubber.

When the insulating wires 2 to 5 are formed by using the insulating layer containing the organopolysiloxane, the total residual amount of the small molecule cyclic siloxanes D4 to D6 remaining in the insulating layer is preferably 100 ppm or less.

The small molecule cyclic siloxanes D4 to D6 belong to volatile organic compounds and have a high vapor pressure despite their high boiling points, so they have the property of being relatively volatile even at room temperature. By setting the total residual amount of the small molecule cyclic siloxanes D4 to D6 having such properties to 100 ppm or less, the smoke emitting characteristics are improved.

When the insulating wires 2 to 5 are constructed by using the insulating layer containing the organopolysiloxane, the total residual amount of the small molecule cyclic siloxanes D4 to D8 should be 500 ppm or less in consideration of the design in a practical range. Suitable for.

Since the small molecule cyclic siloxanes D4 to D8 are VOCs that are particularly liable to become visible smoke in the smoke emission characteristic test, the smoke emission characteristics of the insulated wires 2 to 5 can be improved by intensively reducing the residual amount of these VOCs. It can be improved more effectively.

When the insulating wires 2 to 5 are constructed by using the insulating layer containing the organopolysiloxane, the total residual amount of the small molecule cyclic siloxanes D4 to D10 is preferably 1000 ppm or less.

The small molecule cyclic siloxanes of D9 and D10 tend to evaporate at around 300 ° C, which is the short-term allowable temperature of general silicone rubber-coated insulated wires defined by JCS (Japan Electric Wire Manufacturers Association) Standard No. 168, and in the high temperature range. Affects the smoke characteristics of. Considering the residual amount of D9 and D10, by setting the total residual amount of small molecule cyclic siloxanes D4 to D10 to 1000 ppm or less, the smoke generation temperature of the insulated wires 2 to 5 is brought closer to the short-term allowable temperature of the silicone rubber-coated insulated wire. It is possible to further improve the smoke generation characteristics.

When the insulating layer containing the organopolysiloxane is only one layer, the preferable residual amount of the small molecule cyclic siloxane described above may be such that the insulating layer satisfies the preferable residual amount.

When there are a plurality of insulating layers containing organopolysiloxane, the sum of the total residual amounts of the small molecule cyclic siloxanes remaining in each layer, that is, the total amount of the small molecule cyclic siloxanes remaining in the entire insulated wire is preferable. Is preferable.

Although details are omitted, the effect of reducing the residual amount of substances other than VOC, for example, benzoic acid and its derivative sublimable substance, is expected even when there are a plurality of insulating layers (insulated wires 2 to 5). ..

The insulated wires 1 to 5 of the present invention described above have higher smoke emitting characteristics as compared with the conventional insulated wires, as will be described later.

Hereinafter, examples of the present invention will be shown.

[Example 1]
An insulated wire 1 having a single-layer insulating layer 12 as shown in FIG. 1 was produced.
Specifically, first, a child-twisted conductor in which nine annealed copper wires having a diameter of 0.32 mm are twisted is prepared, and 19 of these child-twisted conductors are twisted in a concentric twisted structure, and the cross-sectional area is ^{equivalent to 15 mm 2} and φ5. Conductor 10 of 1 was formed.
Next, using an extrusion molding machine, the outer periphery of the conductor 10 is coated with a silicone rubber to be an insulating layer 12 with a wall thickness of 1.0 mm, and then heat treatment is performed to crosslink the silicone rubber to insulate the conductor 10 with an outer diameter of 7.1 mm. Wire 1 was obtained.

Next, the insulated wire 1 is cut to a length of 2000 mm and heated in the order of 90 ° C. × 11 hours and 150 ° C. × 11 hours using a heating furnace to evaporate the VOC in the insulating layer 12 to evaporate the insulated wire of Example 1. I got 1-1. When the amount of VOC remaining in the insulating layer 12 was measured by the method described later, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 987 ppm, of which the total amount of D4 to D6 was 42 ppm, and the total amount of D7 and D8 was 42 ppm. The total amount of 324 ppm, D9 and D10 was 621 ppm.

[Example 2]
The same insulated wire 1 as in Example 1 is cut to a length of 2000 mm, immersed in acetone at room temperature for 3 hours, sufficiently dried at room temperature, and then heated under the same conditions as in Example 1 to be used in Example 2. Insulated wire 1-2 was obtained. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 359 ppm, of which the total amount of D4 to D6 is 25 ppm, the total amount of D7 and D8 is 138 ppm, and the total amount of D9 and D10 is. It was 196 ppm.

[Example 3]
An insulated wire 1 similar to that of Example 1 was prepared using a silicone rubber having reduced VOC by heat treatment at 90 ° C. for 5 hours in advance, and the same VOC reduction treatment as that of Example 2 was performed. Insulated electric wires 1-3 of 3 were obtained. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 198 ppm, of which the total amount of D4 to D6 is 31 ppm, the total amount of D7 and D8 is 33 ppm, and the total amount of D9 and D10 is 33 ppm. It was 134 ppm.

[Comparative Example 1]
The same insulated wire as in Example 1 was used as the insulated wire 1'-1 of Comparative Example 1 except that the VOC reduction treatment was not performed. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 10098 ppm, of which the total amount of D4 to D6 is 7430 ppm, the total amount of D7 and D8 is 1909 ppm, and the total amount of D9 and D10 is 1909 ppm. It was 759 ppm.

[Example 4]
A child-twisted conductor obtained by twisting 23 annealed copper wires having a diameter of 0.32 mm was prepared, and 19 of these child-twisted conductors were twisted in a concentric twisted structure to form a conductor 10 having ^{a cross-sectional area of 35 mm 2 and a diameter of 8.1.} ..
Next, using an extrusion molding machine, the outer periphery of the conductor 10 is coated with a silicone rubber to be an insulating layer 12 with a wall thickness of 1.3 mm, and then heat treatment is performed to crosslink the silicone rubber to insulate the conductor 10 with an outer diameter of 10.7 mm. Wire 1 was obtained.

Next, the insulated wire 1 was heated under the same conditions as in Example 1 to evaporate the VOC in the insulating layer 12 to obtain the insulated wires 1-4 of Example 4. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 951 ppm, of which the total amount of D4 to D6 is 19 ppm, the total amount of D7 and D8 is 318 ppm, and the total amount of D9 and D10 is 318 ppm. It is 614 ppm, which is the same residual amount as in Example 1.

[Example 5]
The same insulated wire 1 as in Example 4 was immersed in acetone and heated under the same conditions as in Example 2 to obtain an insulated wire 1-5 of Example 5. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 361 ppm, of which the total amount of D4 to D6 is 30 ppm, the total amount of D7 and D8 is 94 ppm, and the total amount of D9 and D10 is 94 ppm. It is 237 ppm, which is the same residual amount as in Example 2.

[Example 6]
An insulated wire 1 similar to that of Example 4 was prepared using silicone rubber having reduced VOC by heat treatment at 90 ° C. for 5 hours in advance, and the same VOC reduction treatment as that of Example 3 was performed. Insulated wire 1-6 of 6 was obtained. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 201 ppm, of which the total amount of D4 to D6 is 35 ppm, the total amount of D7 and D8 is 31 ppm, and the total amount of D9 and D10 is 31 ppm. It is 135 ppm, which is the same residual amount as in Example 3.

[Comparative Example 2]
The same insulated wire as in Example 3 was used as the insulated wire 1'-2 of Comparative Example 2 except that the VOC reduction treatment was not performed. As for the VOC remaining in the insulating layer 12, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 10142 ppm, of which the total amount of D4 to D6 is 7563 ppm, the total amount of D7 and D8 is 1843 ppm, and the total amount of D9 and D10 is. It is 736 ppm, which is the same residual amount as in Comparative Example 1.

[VOC residual amount measuring method]
The amount of VOC (small molecule cyclic siloxane) remaining in the insulating layer 12 of the insulated wire of each Example and Comparative Example was measured by a gas chromatograph method by extracting acetone. The specific method is shown below.

After shredding the insulating layer 12 collected from the insulated wire, weigh 0.5 mg into a 10 ml sample bottle.

5 ml of acetone was placed in a sample bottle so that the shredded insulating layer 12 was immersed, and ultrasonic treatment was performed for 30 minutes to elute VOC into the acetone.

1 μl of VOC-eluted acetone was collected, introduced into a gas chromatograph, heated, and compared with a calibration curve prepared using a standard sample having a known concentration in advance, and the amount of small molecule cyclic siloxanes of D4 to D10. Was measured.
The heating conditions for gas chromatography are to hold 40 ° C for 1 minute → heat up to 80 ° C at a heating rate of 10 ° C / min → heat up to 120 ° C at a heating rate of 20 ° C / min → 310 at a heating rate of 7 ° C / min. It was heated to ° C. and held for 10 minutes.

[Method for measuring residual sublimable substance]
For the insulated wires of Example 4 and Comparative Example 2, the amount of sublimable substances (benzoic acid and its derivatives) remaining in the insulating layer 12 was measured by a heat-removable gas chromatograph method. The specific method is shown below.

The insulating layer 12 is collected from the insulated wire and weighed 15 mg into the sample tube of the heat desorption device.

The heat desorption device is operated under the conditions shown in Table 1 to generate gas from the sample.

The generated gas was introduced into a gas chromatograph, and the amounts of benzoic acid and its derivatives were measured by comparing with a calibration curve prepared in advance using a standard sample having a known concentration.
The heating conditions for gas chromatography were as follows: 40 ° C. was maintained for 7 minutes → heated to 120 ° C. at a heating rate of 10 ° C./min → heated to 270 ° C. at a heating rate of 20 ° C./min and maintained for 30 minutes.

[Smoke characteristic test]
The smoke emission characteristics were confirmed with reference to the automobile standard JASO D609. Originally, the relationship between the current value at various temperatures and the smoke emission start time is treated as the smoke emission characteristic, but in the present application, the current is passed through the insulated wire 1 at room temperature, and the current value is gradually increased to emit smoke. The magnitude of the temperature and the current value of the insulated wire 1 at the time of occurrence of the above was used as an index of the smoke emission characteristic.
The specific test method is as follows.

(1. Preparation of sample)
A sample was obtained by cutting the insulated wire 1 to a length of 1000 mm and removing the insulating layers 12 at both ends by a length of 20 mm.
A thermocouple-based surface temperature measuring section of the insulating layer 12 was provided 50 mm to the left of the center of the sample, and a thermocouple-based conductor temperature measuring section was provided 50 mm to the right of the center of the sample.

(2. Measurement environment)
It was measured at room temperature (27 ± 5 ° C.).

(3. Current application and smoke temperature recording)
A constant voltage / constant current DC power supply device is connected to the removal portions of the insulating layer 12 provided at both ends of the insulated wire 1, and a predetermined initial current set according to the cross-sectional area of the conductor is energized to keep the conductor temperature constant. Leave it until it becomes.
After the conductor temperature becomes constant, the current value is increased by 10 A every 5 minutes. As the current value increased, the conductor temperature and the surface temperature of the insulating layer also increased, and the conductor temperature when smoke emission from the insulating layer 12 was confirmed was recorded as the smoke emission temperature.
Table 2 shows the results of each example and comparative example.

“<5” in Table 2 indicates that it was below the detection limit and is not included in the total residual amount.

The insulated wire 1'-1 of Comparative Example 1 in which the VOC reduction treatment was not performed emitted smoke at 220A and 210 ° C., whereas the VOC reduction treatment was performed and the total residual amount of VOC was 1500 ppm or less, especially D4. The insulated wire 1-1 of Example 1 in which the total residual amount of D6 is 100 ppm or less and the total residual amount of D7 and D8 is 500 ppm or less emits smoke at 250 A and 260 ° C. Improvement was confirmed.

The insulated wire 1-2 of Example 2 in which the total residual amount of D9 and D10 was reduced to 300 ppm or less by adding a VOC reduction treatment step smoked at 270 A and 300 ° C., and further improvement in smoke emitting characteristics was confirmed.

The insulated wire 1-3 of Example 3 in which the total residual amount of D4 to D10 was about 200 ppm by further adding a VOC reduction treatment step emits smoke at 270 A and 300 ° C., and has the same smoke emission characteristics as in Example 2. there were.
From the above results, it can be said that necessary and sufficient smoke emitting characteristics can be obtained by reducing the small molecule cyclic siloxane so that the total residual amount of D9 and D10 is 300 ppm or less.

The insulated wire 1'-2 of Comparative Example 2, which had not been subjected to the VOC reduction treatment and had a conductor cross-sectional area larger than that of the insulated wire 1'-1 of Comparative Example 1, smoked at 380 A and 200 ° C.
Since the conductor cross-sectional area is larger than that of Comparative Example 1, the temperature rise when the same current is applied is slower than that of Comparative Example 1, and as a result, the current value that can be energized until smoke is increased. It is probable that it was done.

On the other hand, the smoke emitting characteristics of the insulated wire 1'-2 of Comparative Example 2 were worse than those of the insulated wire 1'-1 of Comparative Example 1.
In a general insulated wire, the wall thickness required for the insulating layer 12 increases as the cross-sectional area of the conductor 10 increases.
Further, even when the wall thickness of the insulating layer 12 is designed to be the same, the amount of the insulating layer 12 increases because the outer diameter of the insulating layer 12 also increases as the cross-sectional area of the conductor 10 increases. In the case of the insulated wire 1'-2 of Comparative Example 2, the amount of the insulating layer 12 per unit length is about twice that of the insulated wire 1'-1 of Comparative Example 1.

Since the conductor temperature when smoke is visually confirmed is used as the smoke temperature, the larger the absolute amount of VOC remaining in the sample, the easier it is to visually check the smoke, which tends to be disadvantageous for the smoke characteristic test. Even if the amount of VOC remaining per unit weight of the insulating layer 12 is the same, the absolute amount of VOC remaining in the insulating layer 12 is proportional to the amount of the insulating layer 12, so that the insulated wire 1'-of Comparative Example 2 It is considered that the absolute amount of VOC remaining in 2 is about twice the remaining amount of the insulated wire 1'-1 of Comparative Example 1. As a result, it is considered that the insulated wire 1'-2 of Comparative Example 2 started to emit smoke at a low temperature in terms of measurement.

By performing the VOC reduction treatment on the insulated wire 1'-2 of Comparative Example 2, the total residual amount of VOC is 1500 ppm or less, particularly the total residual amount of D4 to D6 is 100 ppm or less, and the total residual amount of D7 and D8 is reduced. The insulated wires 1-4 of Example 4, which can be said to have a mode of 500 ppm or less, emit smoke at 440 A and 250 ° C., and it was confirmed that the smoke emission characteristics are improved by reducing VOC.

In addition, the amount of benzoic acid and its derivative remaining in the insulated wires 1-4 of Example 4 is significantly reduced as compared with the insulated wires 1'-2 of Comparative Example 2, and is combined with the total remaining amount of D4 to D10. The sum of is 1500 ppm or less. The total residual amount of benzoic acid and its derivatives is 300 ppm or less. It is considered that the insulated wires 1-4 of the fourth embodiment also reduce the sublimating substance benzoic acid and its derivatives during the VOC reduction treatment, which helps to improve the smoke emitting characteristics.

The insulated wire 1-5 of Example 5 in which the total residual amount of D9 and D10 was reduced to 300 ppm or less by adding a VOC reduction treatment step smoked at 520 A and 300 ° C., and further improvement in smoke emitting characteristics was confirmed.

Further, a VOC reduction treatment step was added, and the residual amount of D4 to D10 was set to about 200 ppm. The insulated wire 1-6 of Example 6 emitted smoke at 520 A and 300 ° C. It had the same smoking characteristics.
From the above results, even if the amount of the insulating layer 12 increases as the cross-sectional area of the conductor 10 increases, it is necessary and sufficient to reduce the small molecule cyclic siloxane so that the residual amount of D9 and D10 is 300 ppm or less. It can be said that excellent smoking characteristics can be obtained.

Although there is a difference in the current value that can be energized until smoke is generated due to the difference in the cross-sectional area of the conductor 10, the smoke generation temperature of the insulated wire 1-2 of Example 2 and the insulated wire 1-5 of Example 5 are the same. Met.
Since the insulated wires 1-5 of Example 5 had the same smoke generation temperature as the insulated wires 1-2 of Example 2 despite the increase in the amount of the insulating layer 12, D9 and D10 remained. By setting the total amount to 300 ppm or less, the concentration that can be visually recognized as smoke when VOCs are volatilized and scattered in the air is not reached, and the smoke generation temperature that does not depend on the residual amount of VOCs originally possessed by the insulated wire 1 is obtained. Conceivable.

Comparing Comparative Example 1 and Examples 1 to 3, it was confirmed that the smoke emission characteristics were improved by about 24-43%. This means that it is possible to improve the safety of the insulated wire 1 against heat generation without increasing the cross-sectional area of the conductor 10, and the present invention makes it possible to provide the highly reliable insulated wire 1. It can be said that it has become.

Further, since Example 1 has a higher smoking temperature than Comparative Example 2, it can be considered that the cross-sectional area of the conductor 10 is reduced without lowering the safety based on the smoking characteristics. According to the present invention, the insulated wire 1 It can be said that it has become possible to achieve both the smoke generation characteristics and the reduction in diameter.

The insulated wire 1 of the present invention is provided with various changes in the configuration and cross-sectional area of the conductor 10, the wall thickness and the outer diameter of the insulating layer 12, depending on the intended use and the place of use.

An embodiment of the present invention having two insulating layers 23 and 24 is shown below.

[Example 7]
A child-twisted conductor obtained by twisting 19 annealed copper wires having a diameter of 0.32 mm was prepared, and 53 of these child-twisted conductors were twisted in a concentric twisted structure to form a conductor 20 having ^{a cross-sectional area of 95 mm 2 and a diameter of 14 φ14.}
Next, using an extrusion molding machine, the outer periphery of the conductor 20 is coated with silicone rubber to be the first insulating layer 23 with a wall thickness of 1.2 mm, and then heat treatment is performed to crosslink the silicone rubber to have an outer diameter of 16.4 mm. The first insulating layer 23 of the above was obtained.

The conductor 20 coated with the first insulating layer 23 is immersed in acetone at room temperature for 3 hours, sufficiently dried at room temperature, and then a heating furnace is used in the order of 90 ° C. × 11 hours and 150 ° C. × 11 hours. The VOC in the first insulating layer 23 was evaporated.

Next, the shield layer 28 is provided on the outer periphery of the first insulating layer 23. The shield layer 28 has a braided structure, and a tin-plated annealed copper wire having an outer diameter of 0.2 mm is used as the shield wire.

Next, an aluminum-deposited PET tape was wrapped around the outer periphery of the shield layer 28 to form a permeation suppression layer 26.

Subsequently, using an extrusion molding machine, the outer periphery of the permeation suppression layer 26 is coated with silicone rubber to be the second insulating layer 24 with a wall thickness of 1.5 mm, and then heat treatment is performed to crosslink the silicone rubber to the second. By forming the insulating layer 24, the aspect of the insulated wire 5 is adopted. The outer diameter of the insulated wire 5 was finally 20 mm.

Finally, the insulated wire 5 provided up to the second insulating layer 24 is subjected to the same VOC reduction treatment as the first insulating layer 23 to reduce the VOC in the second insulating layer 24, and the present invention shown in FIG. The insulated wire 5 of the present invention has been completed.

When the amount of VOC remaining in the first insulating layer 23 was measured by the method described later, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 316 ppm, of which the total amount of D4 to D8 was 124 ppm and the total amount of D4 to D6. The amount was 39 ppm.

Similarly, when the amount of VOC remaining in the second insulating layer 24 was measured, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 402 ppm, of which the total amount of D4 to D8 was 166 ppm and the total amount of D4 to D6 was. It was 47 ppm.

That is, as for the total amount of VOCs remaining on the insulated wire 5, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 718 ppm, of which the total amount of D4 to D8 was 290 ppm and the total amount of D4 to D6 was 86 ppm.

[Reference Example]
In the insulated wire 5 of the seventh embodiment, the one obtained by omitting the VOC reduction treatment for the second insulating layer 24 was used as the insulated wire of the reference embodiment.
When the amount of VOC remaining in the second insulating layer 24 of the insulated wire of the reference example was measured, the total amount of small molecule cyclic dimethylsiloxanes of D4 to D10 was 2185 ppm, of which the total amount of D4 to D8 was 1420 ppm, and D4 to D4. The total amount of D6 was 347 ppm.

[Comparative Example 3]
The insulated wire produced by the same material and process as in Example 7 was used as the insulated wire of Comparative Example 3 except that the permeation suppressing layer 26 was not provided.
As for the VOC remaining in the first insulating layer 23 of the insulated wire of Comparative Example 3, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 1403 ppm, of which the total amount of D4 to D8 was 847 ppm and the total amount of D4 to D6 was The VOC remaining in the second insulating layer 24 was 221 ppm, and the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 1300 ppm, of which the total amount of D4 to D8 was 715 ppm and the total amount of D4 to D6 was 211 ppm. rice field.

[Reference comparison example]
In the insulated wire of Comparative Example 3, the one in which the VOC reduction treatment for the second insulating layer 24 was omitted was used as the insulated wire of the reference comparative example.
As for the VOC remaining in the first insulating layer 23 of the insulated wire of the reference comparative example, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 2277 ppm, of which the total amount of D4 to D8 is 1561 ppm and the total amount of D4 to D6 is. The VOC remaining in the second insulating layer 24 was 499 ppm, and the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 was 2434 ppm, of which the total amount of D4 to D8 was 1660 ppm and the total amount of D4 to D6 was 507 ppm. rice field.

[Reference example 1]
In the insulated wire 5 of Example 7, the insulated wire 5 of Reference Example 1 was obtained by completing the process up to the VOC reduction treatment of the first insulating layer 23.
As for the VOC remaining in the first insulating layer 23 of the insulated wire of Reference Example 1, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 359 ppm, of which the total amount of D4 to D8 is 163 ppm and the total amount of D4 to D6 is. It was 25 ppm.

[Reference example 2]
In the insulated wire 5 of Example 7, the one in which the process was completed up to the formation of the first insulating layer 23, that is, the one in which the VOC reduction treatment was omitted from Reference Example 1 was designated as the insulated wire of Reference Example 2.
As for the VOC remaining in the first insulating layer 23 of the insulated wire of Reference Example 2, the total amount of small molecule cyclic dimethylsiloxanes D4 to D10 is 2616 ppm, of which the total amount of D4 to D8 is 1732 ppm and the total amount of D4 to D6 is. It was 244 ppm.

[VOC residual amount measuring method]
The amount of VOC (small molecule cyclic siloxane) remaining in the insulating layer 22 (first insulating layer 23 or second insulating layer 24) of the insulated wires of each Example, Comparative Example, and Reference Example is determined by gas chromatography by extracting acetone. The amount of small molecule cyclic dimethylsiloxane of D3 to D10 was measured by. The specific method is the same as the measurement methods of Examples 1 to 6 and Comparative Examples 1 and 2.

[Smoke characteristic test]
The smoke emission characteristics were confirmed with reference to the automobile standard JASO D609. Originally, the relationship between the current value at various temperatures and the smoke emission start time is treated as the smoke emission characteristic, but in the present application, a constant value current is passed through the insulated wire 5 at room temperature to insulate when smoke is generated. The magnitude of the conductor temperature of the electric wire 5 was used as an index of the smoke emission characteristic. The specific test method is as follows.

(1. Preparation of sample)
An insulated wire 5 was cut to a length of 1000 mm, and the insulating layers 22 at both ends were removed by a length of 20 mm as a sample.
A conductor temperature measuring unit using a thermocouple was provided in the center of the sample.

(2. Measurement environment)
It was measured at room temperature (27 ± 5 ° C.).

(3. Current application and smoke temperature recording)
A constant voltage / constant current DC power supply device was connected to the removing portions of the insulating layer 22 provided at both ends of the insulated wire 5, and a current of 900 A was passed. The conductor temperature when smoke emission from the insulating layer 22 was confirmed was recorded as the smoke emission temperature.
Table 3 shows the results of each example, comparative example, and reference example.

“<5” in Table 3 indicates that it was below the detection limit and is not included in the total residual amount.

The VOCs remaining in the first insulating layer 23 and the second insulating layer 24 of the insulated wire 5 of Example 7 are both about the same as those in Reference Example 1, and the smoke generation temperature is also the insulating layer 22 subjected to the VOC reduction treatment. The result was equal to or higher than that of Reference Example 1, which is an insulated wire having one layer.
No smoke was confirmed in the insulated wire 5 of Example 7 at 280 ° C., and if the temperature was raised further, the temperature approached 300 ° C., which is the short-term allowable temperature, and smoke was generated due to thermal decomposition of the insulating layer itself. Since it was not possible to clearly distinguish it from VOC-derived smoke, the smoke temperature was set to 280 ° C or higher.

Further, when the VOC residual amount of Reference Example and Example 7 is compared, there is no change in the amount of VOC remaining in the first insulating layer 23 before and after the VOC reduction treatment for the second insulating layer 24, and the second insulation Only the amount of VOCs remaining in layer 24 is reduced. From this result, the presence of the permeation suppressing layer 26 suppresses the phenomenon that a part of the VOC desorbed from the second insulating layer 24 is re-adsorbed to the first insulating layer 23 during the VOC reduction treatment for the second insulating layer 24. It was confirmed that this contributed to the reduction of the total amount of VOC contained in the insulated wire.

On the other hand, the VOCs remaining in the first insulating layer 23 and the second insulating layer 24 of the insulated wire of Comparative Example 3 both exceed 1000 ppm, and the VOCs remaining in the first insulating layer 23 and the second insulating layer 24, respectively. Is less than that of Reference Example 2, but the total amount of VOCs remaining in the first insulating layer 23 and the second insulating layer 24 is about the same as that of Reference Example 2. The smoke generation temperature was 220 ° C., which was not much different from that of Reference Example 2, which is an insulated wire having one insulating layer 22 not subjected to VOC reduction treatment.

Further, looking at the results of the reference comparative example, although the first insulating layer 23 has been subjected to the VOC reduction treatment in advance, the first insulating layer 23 is at the stage where the second insulating layer 24 is provided. The amount of VOC remaining in the second insulating layer 24 is about the same as that of the second insulating layer 24.
From this, since the insulated wire of the reference comparative example does not have the permeation suppressing layer 26 between the first insulating layer 23 and the second insulating layer 24, the second insulation is performed in the process of coating the second insulating layer 24 to cross-linking. It is considered that the VOCs desorbed from the layer 24 have migrated to the first insulating layer 23, and the amount of VOCs remaining in the first insulating layer 23 has increased.

Comparing the VOC residual amount of the reference comparative example and the comparative example 3, it can be confirmed that the VOC residual amount of the insulated wire of the comparative example was reduced by the VOC reduction treatment for the insulated wire of the reference comparative example, but the smoke generation characteristics It is a decrease that does not contribute significantly to improvement.
From this, since the insulated wire of the reference comparative example does not have the permeation suppressing layer 26 between the first insulating layer 23 and the second insulating layer 24, the VOC is applied to the second insulating layer 24 in order to use the insulated wire of the comparative example. When the reduction treatment is performed, a phenomenon occurs in which a part of the VOC desorbed from the second insulating layer 24 is re-adsorbed to the first insulating layer 23, and the effect of reducing the total amount of VOC contained in the insulated wire is limited. It is thought that it has become.

The insulated wire of the present invention has the configuration and cross-sectional area of the conductor 20, the wall thickness and outer diameter of the first insulating layer 23 and the second insulating layer 24, and the aspects of the permeation suppressing layer 26 and the shield layer 28, depending on the application and the place of use. Is provided in various modifications.

This application is based on Japanese Patent Application No. 2018-150855 filed on August 9, 2018 and Japanese Patent Application Patent No. 2018-247461 filed on December 28, 2018. The specification, claims, and the entire drawings of Japanese Patent Application Japanese Patent Application No. 2018-150855 and Japanese Patent Application No. 2018-247461 shall be incorporated into this specification as a reference.

It goes without saying that the above examples are merely examples of the present invention, and various modifications and applications are possible within the scope of the idea of the present invention, and are appropriately modified and provided.
The present invention is particularly suitable for high-voltage power cables used in automobiles, electric and electronic devices, etc., but the intended use is not limited to these, and in situations where smoke generation characteristics are required. The present invention may be applied to low voltage cables, insulated wires, and the like.

1, 2, 3, 4, 5 Insulated wires 10, 20 Conductors 12, 22 Insulated layer 23 First insulating layer 24 Second insulating layer 26 Permeation suppression layer 28 Shield layer

Claims (20)

An insulated wire in which an insulating layer is coated around a conductor, and the total residual amount of volatile organic compounds and quasi-volatile organic compounds having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the insulating layer is 1500 ppm or less. An insulated wire characterized by being. The insulated wire according to claim 1, wherein the insulating layer contains an organopolysiloxane. The insulated wire according to claim 2, wherein the volatile organic compound and the quasi-volatile organic compound having a boiling point in the range of 150 ° C. to 360 ° C. are low molecular weight cyclic siloxanes of D4 to D10. The insulated wire according to claim 3, wherein at least one of the small molecule cyclic siloxanes D4 to D6 remaining in the insulating layer has a residual amount of 1000 ppm or less. The insulated wire according to claim 3 or 4, wherein the total residual amount of the small molecule cyclic siloxanes D4 to D8 remaining in the insulating layer is 500 ppm or less. The insulated wire according to any one of claims 3 to 5, wherein the total residual amount of the small molecule cyclic siloxanes D4 to D10 remaining in the insulating layer is 400 ppm or less. The insulated wire according to any one of claims 3 to 6, wherein the residual amount of the small molecule cyclic siloxane of D6 remaining in the insulating layer is 100 ppm or less. The insulated wire according to any one of claims 3 to 7, wherein the residual amount of the small molecule cyclic siloxane of D8 remaining in the insulating layer is 300 ppm or less. The insulated wire according to any one of claims 3 to 8, wherein the residual amount of the small molecule cyclic siloxane of D10 remaining in the insulating layer is 200 ppm or less. The sum of the total residual amount of volatile organic compounds and quasi-volatile organic compounds having a boiling point in the range of 150 ° C. to 360 ° C. remaining in the insulating layer and the total residual amount of sublimable substances remaining in the insulating layer is The insulated wire according to any one of claims 1 to 9, which remains in the insulating layer having an amount of 1500 ppm or less. The insulated wire according to claim 10, wherein the total residual amount of the sublimable substance remaining in the insulating layer is 300 ppm or less. The insulated wire according to claim 10 or 11, wherein the sublimable substance is benzoic acid or a derivative of benzoic acid. An insulated wire in which at least two insulating layers including a first insulating layer and a second insulating layer are coated around a conductor.
An insulated wire having a boiling point remaining in all the insulating layers in the range of 150 ° C. to 360 ° C. and a total residual amount of volatile organic compounds and quasi-volatile organic compounds of 1500 ppm or less. A permeation-suppressing layer between the first insulating layer and the second insulating layer, which exhibits low permeability to volatile organic compounds and quasi-volatile organic compounds having a boiling point in the range of 150 ° C. to 360 ° C. The insulated electric wire according to claim 13, wherein the insulated wire is provided. The insulated wire according to claim 13 or 14, wherein a shield layer is provided between the first insulating layer and the second insulating layer. The insulated wire according to any one of claims 13 to 15, wherein at least one of the first insulating layer and the second insulating layer contains an organopolysiloxane. The insulated wire according to claim 16, wherein the volatile organic compound and the quasi-volatile organic compound having a boiling point in the range of 150 ° C. to 360 ° C. are low molecular weight cyclic siloxanes of D4 to D10. The insulated wire according to claim 17, wherein the total residual amount of the small molecule cyclic siloxanes D4 to D6 remaining in the insulating layer containing the organopolysiloxane is 100 ppm or less. The insulated wire according to claim 17 or 18, wherein the total residual amount of the small molecule cyclic siloxanes D4 to D8 remaining in the insulating layer containing the organopolysiloxane is 500 ppm or less. The method according to any one of claims 17 to 19, wherein the total residual amount of the small molecule cyclic siloxanes D4 to D10 remaining in the insulating layer containing the organopolysiloxane is 1000 ppm or less. Insulated wire.

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