JP2023111788A - conductive fiber material - Google Patents

Abstract

To provide a conductive fiber material having fire retardancy.SOLUTION: A conductive fiber material includes: a fabric having first and second surfaces; a metal layer covered on the thread of the fabric; a first fire retardancy layer laminated on a first surface side of the fabric and including a fire retardant; and a second fire retardancy layer laminated on a second surface side of the fabric and including the fire retardant. Some threads of the fabric are exposed from each fire-resistant layer; in both surfaces of the fabric, either one of the warp or the weft are embossed rather than the other; and at least one of the warp and the weft is not twisted yarn.SELECTED DRAWING: Figure 1

Description

The present invention relates to conductive fiber materials.

BACKGROUND ART Conventionally, there has been proposed a conductive fiber material that is used as a conductive material such as an electromagnetic wave shielding material or a grounding material, in which a metal film is formed on the surface of a synthetic fiber. For example, Patent Document 1 discloses a conductive fiber material in which a metal coating is formed on a fabric using a thermoplastic synthetic fiber multifilament yarn having a non-circular cross section with an average oblateness of 1.5 to 5. ing.

Utility Model Registration No. 3070467

By the way, the conductive fiber material as described above may burn due to heat depending on the usage environment, and therefore it has been desired to have flame retardancy. The present invention has been made to solve the above problems, and an object of the present invention is to provide a flame-retardant conductive fiber material.

Section 1. A conductive fiber material,
a fabric having a first side and a second side;
a metal layer coated on the threads of the fabric;
A first flame retardant layer laminated on the first surface side of the fabric and containing a flame retardant;
A second flame retardant layer laminated on the second surface side of the fabric and containing a flame retardant;
with
Part of the thread of the fabric is exposed from each flame-retardant layer,
Either one of the warp and the weft is more raised than the other on both sides of the fabric,
A conductive fiber material, wherein at least one of the warp and the weft is not twisted.

Section 2. Item 2. The conductive fiber material according to item 1, wherein the amount of each flame-retardant layer applied is 15 to 80 g/m ² .

Item 3. Item 3. The conductive fiber material according to Item 1 or 2, wherein both the warp yarn and the weft yarn are not twisted yarns.

Section 4. 4. The conductive fiber material according to any one of Items 1 to 3, wherein the height of one of the warp yarns and the weft yarns is 20 to 50 μm above the other.

Item 5. Item 5. The conductive fiber material according to any one of Items 1 to 4, wherein one of the warp yarn and the weft yarn has a higher waviness height than the other.

According to the present invention, a conductive fiber material having flame retardancy can be provided.

1 is a cross-sectional view of one embodiment of a conductive fiber material according to the present invention; FIG. 2 is an enlarged sectional view of FIG. 1; FIG. 3 is an enlarged cross-sectional view of a cross section different from FIG. 2 by 90 degrees; FIG. 1 is a photograph of the surface of Example 1. FIG. 1 is a photograph of a cross section of Example 1. FIG. 6 is a photograph of a cross section of Example 1 different from FIG. 5. FIG. It is a photograph of a cross section different from FIG. 6 by 90 degrees.

An embodiment of the conductive fiber material according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the conductive fiber material according to this embodiment. As shown in FIG. 1, the conductive fiber material comprises a fabric 1 having a first side and a second side, a metal layer coated on the threads of the fabric 1, and a metal layer laminated on the first side of the fabric 1. and a second flame-retardant layer 3 laminated on the second surface side of the fabric 1 . In addition, FIG. 1 schematically shows a form in which a part of the fabric 1 is exposed, and does not strictly show the shape of both the flame-retardant layers 2 and 3 . These members will be described in detail below.

<1. Textile>
The yarn used for the woven fabric 1 of the present invention is preferably yarn mainly composed of polyester filaments in consideration of workability and durability. All yarns may be made of polyester, but synthetic fibers such as polyamide, acrylic and polyolefin, regenerated fibers such as rayon, and semi-synthetic fibers such as acetate may also be used. Alternatively, a plurality of fibers among the fibers described above may be processed by blending, entangling, twisting, or the like. Although the yarn used is not particularly limited, for example, it is preferable to use a multifilament with a total fineness of 33 to 220 dtex, more preferably a multifilament of 56 to 84 dtex.

Although the thickness of the woven fabric 1 is not particularly limited, it is preferably, for example, 40 to 250 μm, more preferably 60 to 200 μm. If the thickness of the woven fabric 1 is less than 40 µm, the strength may not be sufficient. I don't like it either. Moreover, if the thickness of the woven fabric 1 is large, there is a possibility that the bending resistance, which will be described later, is also affected. The thickness of the cloth material can be measured with a thickness meter (eg Peacock G-6 manufactured by Ozaki Seisakusho Co., Ltd.). Also, the thickness is obtained by performing measurements at 10 locations and calculating the average value at the remaining 8 locations excluding the maximum and minimum values.

In general, woven fabrics do not have a structure in which one of the warp and weft threads sinks and the other floats, and the floating height is often close to zero. However, in the present invention, as shown in FIG. 2, it is preferable to set the floating height X to 20 μm to 70 μm, particularly 30 to 50 μm. If the floating height is less than 20 μm, the amount of the flame retardant-containing resin that can be applied is reduced, and if the floating height is greater than 70 μm, the weavability of the fabric may deteriorate. Note that the floating height is determined by measuring 10 points and calculating the average value of the remaining 8 points excluding the maximum and minimum values.

As shown in FIG. 2, the floating height X is obtained by cutting the fabric 1 in the direction perpendicular to the surface and measuring the warp (floating here) 12 and the weft (sinking here) when viewed from the cross-sectional direction. It refers to the difference in surface height of each of the 11. In order to produce the woven fabric 1 having such a floating height X, the tension during weaving, scouring, and heat setting treatment, and the thickness of the warp and weft, etc., are changed, and in the same manner one yarn is made stronger than the other. Floating height can also be created by shrinking more or by making the thread thicker. For example, the scouring process is performed by scouring while pulling the fabric of the fabric, and if the tension is increased during heat setting after that, the floating height will be reduced, and the reverse method, that is, either one of the wefts and wefts will be used. Scouring and heat setting without pulling as much as possible can produce a woven fabric with a large floating height. Further, the floating height X can be further increased by combining two or more of the above three methods (high tension, high shrinkage, thick yarn). There is no particular limitation on which of the warp 12 and the weft 11 is used as the floating thread or the sinking thread, and any of them may be used.

Further, in the woven fabric 1 according to the present embodiment, the difference in waviness between the warp yarns 12 and the weft yarns 11 can be increased. FIG. 3 is a cross-sectional view of a plane that intersects FIG. 2 by 90°. As shown in FIGS. 2 and 3, in this embodiment, the thickness (waviness height) A of the warp yarns 12 of the fabric 1 and the thickness (waviness height) B of the weft yarns 11 are different. In this example, the waviness height of the warp yarns 12 is greater than the waviness height of the weft yarns 11 . The difference in undulation height (|AB|) is, for example, preferably 20 to 140 μm, more preferably 50 to 130 μm, even more preferably 65 to 120 μm. In order to provide such a difference in swell height, the same method as the method for providing the floating height X described above can be used. Also, the measurement method can be the same as that for the floating height.

<2. Metal layer>
Examples of metals forming the metal layer include gold, silver, copper, zinc, nickel, and alloys thereof. Among them, copper and nickel are preferable in consideration of conductivity and manufacturing cost. The metal layer formed of these metals is preferably configured by stacking one or two metal layers. Laminating three or more metal layers may increase the thickness of the metal layers and make the conductive fiber material hard. Moreover, there is also a problem that the processing cost increases. When the metal layer is composed of two layers, the same kind of metal may be used as two layers, or different metals may be laminated. These can be appropriately set in consideration of required shielding properties and durability.

The metal layer can be applied to the threads of the fabric 1 by vapor deposition, sputtering, electroplating, electroless plating or the like. Among these methods, the electroless plating method or a combination of the electroless plating method and the electroplating method is preferably used from the viewpoint of uniformity of the formed metal layer and productivity. The coating amount of the metal layer is, for example, preferably 5 to 50 g/m ² , more preferably 10 to 40 g/m ² , particularly preferably 15 to 30 g/m ² . If the coating amount is less than 5 g/m ² , the surface conductivity and electromagnetic wave shielding properties may be impaired. On the other hand, if the coating amount is more than 50 g/m ² , the texture may become hard and the cost may increase.

For example, when the fabric 1 is coated with metal on each side by sputtering or the like, the metals coated on the first side and the second side may be the same or different.

<3. Flame-retardant layer>
The first flame-retardant layer 2 and the second flame-retardant layer 3 contain a thermoplastic resin and a flame retardant. Examples of thermoplastic resins include urethane resins, acrylic resins, and ester resins. Among these resins, urethane resins are preferred because they are superior to acrylic resins and ester resins in terms of flame retardancy, friction strength, and flexibility. Among urethane resins, non-yellowing ester-based urethanes are preferable in terms of durability and economy. In these urethane resins, aromatic isocyanates such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI) are preferably used as isocyanates, and polyester-based diols composed of aliphatic carboxylic acids and glycol components are preferably used as polyols. .

Flame retardants that can be used in the present invention include halogen-based flame retardants, phosphorus-based flame retardants, antimony trioxide, and the like. Combined use of a halogen-based flame retardant and a phosphorus-based flame retardant exhibits an excellent flame-retardant effect due to synergistic action, and antimony trioxide enhances this synergistic effect. is preferably used.

Halogen-based flame retardants that can be used in the present invention are roughly classified into bromine-based flame retardants and chloro-based flame retardants. In the present invention, it is preferable to use bromine-based flame retardants. Furthermore, bromine-based flame retardants are classified into organic bromine compounds and inorganic bromine compounds, and it is particularly preferable to use organic bromine compounds in the present invention. An organic bromine compound refers to an organic compound substituted with one or more bromine atoms. However, phosphate esters containing one or more bromine atoms are excluded. Examples of organic bromine compounds include hexabromobenzene, hexabromobisphenyl ether, tribromophenol, decabromodiphenylethane, Pigarol SR103 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and Pigarol SR700 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). etc. are exemplified. In the present invention, hexabromobenzene and hexabromobisphenol are preferred organic bromine compounds.

Further, in consideration of recent environmental measures, the above organic bromine compounds other than decabromodiphenylethane are more preferable.

Phosphorus-based flame retardants are classified into inorganic phosphates, nitrogen-containing phosphorus compounds, non-halogen phosphates, halogen-containing phosphates, and the like. Examples of inorganic phosphate include ammonium polyphosphate. Examples of nitrogen-containing phosphorus compounds include phosphonitrile chloride derivatives and phosphonoamide compounds.

Non-halogen phosphates include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, and the like. A halogen-containing phosphate ester is a phosphate ester containing one or more halogen atoms (including a bromine atom) in one molecule. A bromine atom or a chlorine atom is preferable as the halogen atom. Halogen atoms and phosphorus atoms work synergistically with each other to exhibit a strong flame retardant effect. Halogen-containing phosphates include tris(chloroethyl) phosphate, tris(dichloropropyl) phosphate, tris(chloropropyl) phosphate, bis(2,3-dibromopropyl) 2,3-dichloropropyl phosphate, tris(2,3 -dibromopropyl)phosphate, bis(chloropropyl)monooctylphosphate and the like.

In the present invention, tris(chloroethyl) phosphate and bis(chloropropyl) monooctyl phosphate are preferably used. In the present invention, phosphates substituted with one or more bromine atoms are classified as halogen-containing phosphates. In the present invention, it is preferable to use a non-halogen phosphate or a halogen-containing phosphate as the phosphate.

The weight ratio of the flame retardant to the thermoplastic resin is 200 to 400%, preferably 300 to 350%, of the organic bromine compound, 50 to 150%, preferably 80 to 120%, of the phosphate ester, and 60% of antimony trioxide. ~170%, preferably 100-150%. If the ratio is higher than this, the resin film becomes brittle, and if the ratio is lower, sufficient flame retardancy cannot be obtained. Remarkable flame retardancy can be obtained by combining three kinds of flame retardants: an organic bromine compound, a phosphate ester, and antimony trioxide. This is because a particularly excellent synergistic effect can be obtained by using these three flame retardants in combination.

Other additives may be added to the flame-retardant layers 2 and 3 for the purpose of imparting functionality such as coloring, touch adjustment, and insulating properties, as long as they do not impair their performance. Specific examples of such additives include elastomers such as silicone rubbers, olefin copolymers, modified nitrile rubbers and modified polybutadiene rubbers, thermoplastic resins such as polyethylene, and pigments.

The amount of each flame-retardant layer 2, 3 applied is preferably 15 to 80 g/m ² , more preferably 20 to 60 g/m ² . If the applied amount is less than 15 g/m ² , sufficient flame retardancy may not be obtained. On the other hand, if the amount applied is more than 80 g/m ² , the surface conductivity may be impaired and the cost may increase.

Although the method of laminating the flame-retardant layers 2 and 3 is not particularly limited, examples thereof include a padding method, a coating method, and a lamination method. By such a method, the viscosity of each flame-retardant layer 2, 3 can be appropriately adjusted. Also, the first flame-retardant layer 2 and the second flame-retardant layer 3 may be made of the same material, or may be made of different materials.

<4. Applications of the conductive fiber material>
The conductive fiber material according to this embodiment can be used for cable covers, shield covers, shield cases, shield curtains, shield tapes, and the like for electronic equipment.

<5. Features>
The conductive fiber material according to this embodiment can obtain the following effects.
(1) Since at least one of the warp yarns 12 and the weft yarns 11 of the fabric 1 is not twisted, the flame-retardant layers 2 and 3 can penetrate between the fibers constituting the yarns. Therefore, high flame retardancy can be obtained.

(2) Since at least one of the warp yarns 12 and the weft yarns 11 of the fabric 1 is not twisted, the flexibility of the fabric 1 is increased. Therefore, for example, as will be described later, it becomes easier to wind the conductive fiber material around the cable, and workability is improved.

(3) The flame-retardant layers 2 and 3 are laminated such that a part of the fabric 1 is exposed to the outside. That is, since the entire surface of the fabric 1 is not covered with the flame-retardant layers 2 and 3, flexibility can be ensured. On the other hand, unevenness is formed on the surface of the fabric 1 so that the flame-retardant layers 2 and 3 are firmly laminated on the surface of the fabric 1, and the flame-retardant layers 2 and 3 are laminated on the concave portions. . The unevenness is obtained by forming the floating height X described above. In addition to this, unevenness can be formed by forming a difference in undulation height.

The ratio of the exposed area of the warp yarns 12 and the weft yarns 11 of the fabric 1 to the surface of the conductive fiber material is preferably 20 to 60%, for example. As a method for obtaining the ratio of the exposed area, for example, a photograph may be printed and cut into the flame-retardant layers 2 and 3 and the uncoated portion, and the ratio may be obtained from the weight ratio. The ratio of the portion where 3 is not laminated may be obtained. Also, the ratio of the areas on the first surface side and the second surface side of the conductive fiber material is obtained, and the average thereof is taken as the ratio of the exposed area.

Examples of the present invention will be described below. However, the present invention is not limited to the following examples.

<1. Preparation of Examples and Comparative Examples>
Conductive fiber materials according to Examples 1 to 3 and Comparative Examples were prepared as follows.

(Example 1)
84dtex/36f polyester textured yarn was used for the warp of the fabric, and 84dtex/36f polyester textured yarn was used for the weft. At this time, the textured yarn used was a two-heater untwisted yarn, and the warp yarn was subjected to sizing before warping. As a result, a plain weave having a warp density of 86/25.4 mm, a weft density of 82/25.4 mm and a fabric thickness of 85 μm was obtained. A scouring, drying and heat-treated fabric was then obtained. In addition, the floating height and waviness height of the fabric were adjusted as described in Table 1 below. This fabric was then immersed in an aqueous solution containing 0.3 g/L of palladium chloride, 30 g/L of stannous chloride and 300 ml/L of 36% hydrochloric acid at 40° C. for 2 minutes and then washed with water.

Subsequently, it was immersed in borofluoric acid at an acid concentration of 0.1 N and 30° C. for 5 minutes and then washed with water. Next, it was immersed in an electroless copper plating solution containing 7.5 g/L of copper sulfate, 30 ml/L of 37% formalin, and 85 g/L of Rochelle salt at 30° C. for 5 minutes and then washed with water. Subsequently, it was immersed in a nickel electroplating solution containing 300 g/L of nickel sulfamate, 30 g/L of boric acid, and 15 g/L of nickel chloride at pH 3.7 and 35° C. for 10 minutes at a current density of 5 A/dm ² to deposit nickel. It was washed with water after lamination.

The fabric threads were plated with 10 g/m ² of copper and 4 g/m ² of nickel in that order. The threads of the fabric were thus coated with a metal layer. The basis weight of the metal-coated fabric obtained was 64 g/m ² . Next, both sides of this metal-coated fabric were coated with a mixed treatment solution of formulation 1 below using a knife and dried at 130° C. for 2 minutes to form a flame-retardant layer. The total amount applied to each surface was 50 g/m ² in terms of solid content.

(Prescription 1)
Crisbon 2016EL (urethane resin manufactured by DIC Corporation) 100 parts Bigol Bui-854 (bromine-based compound, antimony trioxide, chlorine-based compound phosphate ester manufactured by Daikyo Chemical Co., Ltd.) 160 parts N,N-dimethylformamide is added to the above. viscosity was adjusted to 8000 mPa·s. As a viscometer, a B-type viscometer manufactured by Tokyo Keiki Seisakusho was used (rotor number: 4, number of revolutions: 30 rpm). This point also applies to viscosity, which will be described later.

(Example 2)
Example 2 differs from Example 1 in that the floating height and waviness height of the fabric shown in Table 1, the amount of flame-retardant layer applied, and the warp twist are the same. Description is omitted. In Example 2, the amount of the flame-retardant layer applied was set to 40 g/m ² in terms of solid content.

(Example 3)
Example 3 differs from Example 1 in that the floating height and waviness height of the fabric shown in Table 1 and the twist in the warp are the same.

(Comparative example)
The comparative example differs from Example 1 in that the floating height and waviness height of the fabric shown in Table 1, the amount of flame-retardant layer applied, and the use of twisted yarns for the warp and weft are the same. Therefore, the description is omitted. In the comparative example, the amount of the flame-retardant layer applied was 13 g/m ² in terms of solid content.

<2. Evaluation of Examples and Comparative Examples>
The following evaluations were performed on the examples and comparative examples produced as described above.
(1) Bending resistance Measured according to JIS-L-1096:2010 (8.21.1 A method (45° cantilever method)). Here, the measurement was performed with the first surface facing up and with the second surface facing down.

(2) Flame retardancy Evaluation was made according to the UL94 VTM-0 method.

(3) Conductivity Using a resistance value measuring instrument (Mitsubishi Chemical Analytic Tech Co., Ltd. Lorestar MP), according to the probe four-terminal four-probe measurement method (JIS-K-7194), the first surface side and the second surface side was measured (unit: Ω/□). If the surface resistance value was 1Ω/□ or less, it was judged to have conductivity.

(4) Back leakage of resin When resin was applied to one side of the conductive fiber material, the degree of resin back leakage from the other side of the conductive fiber material was judged visually.
1: No back leakage of resin 2: Slight back leakage 3: Much back leakage of resin

(5) Flexibility A piece of each of Examples 1 to 3 and Comparative Example was cut to 1 m in the warp direction and 20 cm in the weft direction. Ten cables each having a diameter of 5 mm and a length of 1.2 m were prepared, and the cables of Examples 1 to 3 and Comparative Example were placed parallel to the warp direction and wound in the weft direction to confirm the winding workability.
1: Easy to wrap, no return of fabric at all 2: Easy to wrap, but slight return of fabric 3: Difficult to wrap, fabric tries to return flat

(6) Exposed Area The ratio of the area of the warp and weft exposed from the flame-retardant layer to the surface area of the conductive fiber material was determined. The method for calculating the ratio of the exposed area is as described above.

The results of the above evaluation are as follows.

According to Table 1, in Examples 1 to 3, since at least one of the warp and weft yarns is not twisted, the flame-retardant layer can penetrate the fibers of the fabric. Therefore, flame retardancy can be reliably ensured. In addition, in Examples 1 to 3, the difference in floating height and waviness height of the fabric is formed, and this also allows the flame-retardant layer to be held on the surface of the fabric. On the other hand, in the comparative example, the threads of the fabric were twisted, and the difference in floating height and waviness height was not formed, so the amount of the flame-retardant layer applied was small. As a result, flame retardancy is rejected. In addition, since twisted yarn is used, there are gaps between the yarns of the fabric, causing resin leakage.

The back leakage of the resin is mainly caused by the density and thickness of the warp and weft of the conductive fiber material, but is also caused by the presence or absence of twist of the yarn as described above. The present inventors have confirmed that yarn gaps are more likely to occur in yarns with the same density structure and twisted yarns than in yarns without twists, and resin leakage (back leakage) tends to occur from these gaps.

The yarns of the fabric of the comparative example are twisted and therefore have low flexibility. In addition, since Example 1 uses untwisted yarns for both the warp and weft, the flexibility is lower than in Examples 2 and 3 and the comparative examples.

Since Example 3 has a larger floating height than Example 2, even if the amount of the flame-retardant layer applied is the same, the resin forming the flame-retardant layer is easily caught on uneven steps on the surface of the fabric. As a result, the exposed area is large.

4 is a photograph of the surface of Example 1. FIG. According to this figure, the surface of the fabric coated with the metal layer is exposed, but the flame-retardant layer is laminated near the boundary between the floating threads and the sinking threads.

5 is a photograph of a cross section of Example 1. FIG. According to FIG. 5, the height difference between the floating threads and the sinking threads of the fabric can be confirmed.

6 is a photograph of a cross section of Example 1 different from FIG. 5, and FIG. 7 is a photograph of a cross section different from FIG. 6 by 90 degrees. 6 and 7, the difference in waviness between the warp and the weft can be clearly confirmed.

In Examples 2 and 3, as in Example 1, the difference in height between the floating yarn and the sinking yarn of the fabric and the difference in waviness can be confirmed.

1 Textile 2 First flame-retardant layer 3 Second flame-retardant layer

Claims (5)

A conductive fiber material,
a fabric having a first side and a second side;
a metal layer coated on the threads of the fabric;
A first flame retardant layer laminated on the first surface side of the fabric and containing a flame retardant;
A second flame retardant layer laminated on the second surface side of the fabric and containing a flame retardant;
with
Part of the thread of the fabric is exposed from each flame-retardant layer,
Either one of the warp and the weft is more raised than the other on both sides of the fabric,
An electrically conductive fiber material, wherein at least one of the warp yarns and the weft yarns is not a twisted yarn. The conductive fiber material according to claim 1, wherein the application amount of each flame retardant layer is 15-80 g/m ² . 3. Conductive fiber material according to claim 1 or 2, wherein both the warp yarns and the weft yarns are non-twisted yarns. The conductive fiber material according to any one of claims 1 to 3, wherein one of the warp and the weft has a height of 20 to 50 µm above the other. The conductive fiber material according to any one of claims 1 to 4, wherein the height of waviness of one of said warp yarns and said weft yarns is greater than the height of waviness of the other yarn.