JP6210433B2 - Earphone cord and earphone - Google Patents

Description

  The present invention relates to an earphone cord and an earphone.

Conventionally, a soft polyvinyl chloride resin has been mainly used for an insulating layer of an earphone cord (see, for example, paragraph [0006] of Patent Document 1).

Japanese Patent Laid-Open No. 5-347109 (paragraph [0006])

However, soft polyvinyl chloride resin has a problem of yellowing with time because of poor light resistance. The light-resistant stability of transparent soft polyvinyl chloride resin can be improved by adding a benzotriazole-based light stabilizer or a hindered amine-based light stabilizer, but this is a trade-off relationship that impairs transparency. there were.

Since the earphone cord is easily used and easily damaged, the conductor is likely to be disconnected. However, if a covering material having a high elastic modulus is used in order to prevent the earphone cord from being damaged, a problem occurs in handling.

With the above-mentioned earphone cord that has been yellowed over time, an earphone cord with a color that is not transparent, and an earphone cord that has been scratched and has lost transparency, it cannot be visually confirmed whether or not the conductor is disconnected.

SUMMARY OF THE INVENTION An object of the present invention is to provide an earphone cord that has excellent light resistance stability and is not easily damaged, and an earphone including the earphone cord.

In order to achieve the above object, the present invention provides the following earphone cord and earphone. In the present invention, the term “earphone” includes all sound listening devices including cords such as earphones, headphones, and neckphones. The earphone cord is a cord provided in the earphone.

[1] An earphone cord comprising a conductor and a first outer layer using an ionomer resin coated around the conductor.
[2] The earphone cord according to [1], wherein the ionomer resin has a flexural modulus of 30 to 50 MPa.
[3] The earphone cord according to [1] or [2], wherein the metal ion species contributing to the intermolecular bond in the ionomer resin is Zn.
[4] A second outer layer that covers the first outer layer, wherein the second outer layer is selected from ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-α olefin copolymer, and polyamide 1 The earphone cord according to any one of [1] to [3], wherein the earphone cord is formed using seeds or more.
[5] The earphone cord according to [4], wherein the thickness of the second outer layer is 100 μm or less.
[6] An inner layer covering the conductor is provided on the inner side of the first outer layer, and the inner layer is one or more selected from ethylene-tetrafluoroethylene copolymer (ETFE) and ethylene-α olefin copolymer. The earphone cord according to any one of [1] to [5], wherein the earphone cord is formed using
[7] An earphone comprising the earphone cord according to any one of [1] to [6].

According to the present invention, it is possible to provide an earphone cord that has excellent light resistance stability and is not easily damaged, and an earphone including the earphone cord.

It is a cross-sectional view showing an example of an earphone cord according to an embodiment of the present invention. It is the schematic which shows an example of the earphone which concerns on embodiment of this invention.

[Earphone cord]
FIG. 1 is a cross-sectional view showing an example of an earphone cord according to an embodiment of the present invention.
The earphone cord 10 according to the embodiment of the present invention includes a conductor 2 and a first outer layer 4 made of an ionomer resin and coated around the conductor 2. For example, as shown in FIG. 1, an earphone cord 10 uses a plurality of conductors 2 wound around an aramid fiber 1, an inner layer 3 that covers the plurality of conductors 2, and an ionomer resin that covers the inner layer 3. 1 outer layer 4 and a second outer layer 5 covering the first outer layer 4.

(Conductor 2)
The conductor 2 is not particularly limited, but a plurality of conductors are preferably used. For example, as shown in FIG. 1, six conductors 2 are wound around a linear aramid fiber 1 and further 12
Used by wrapping the book. It is preferable to wind it around an aramid fiber or the like in terms of durability.

As the material of the conductor 2, soft copper or the like can be used. Those plated with nickel, gold, silver, tin or the like may be used, and those plated with silver are preferred.

(First outer layer 4)
The earphone cord 10 has a first outer layer (insulating layer) 4 using an ionomer resin.

The above-mentioned ionomer resin has a flexural modulus of 30 to 50M in terms of light resistance and disconnection visibility.
Pa is preferable, and 35 to 45 MPa is more preferable. In addition, the metal ion species contributing to the intermolecular bond in the ionomer resin is Zn in terms of light stability and electrical characteristics.
It is preferable that Na or K may be used, but the electrical characteristics tend to deteriorate.
Zn is preferred.

As the ionomer resin, for example, a ternary ionomer resin (ternary copolymer) or a binary ionomer resin (binary copolymer) can be used. A ternary ionomer resin is preferable from the viewpoint of flexibility and interfacial adhesion with the second outer layer. As the ternary ionomer resin, for example, an ethylene / methacrylic acid / ester ionomer resin can be suitably used.

Examples of ethylene / methacrylic acid / ester ionomer resins include ethylene-
Preferred examples include a methacrylic acid-butyl acrylate terpolymer, an ethylene-methacrylic acid-isobutyl acrylate terpolymer, and an ethylene-methacrylic acid-ethyl acrylate terpolymer.

The methacrylic acid / ester content in the ethylene / methacrylic acid / ester ionomer resin is preferably 10% by mass or more from the viewpoint of light resistance (weather resistance). If the amount is less than 10% by mass, the ethylene portion increases, and thus sufficient light stability (weather resistance) may not be obtained. Further, the higher the methacrylic acid / ester content, the better. However, if it exceeds 30% by mass, it becomes difficult to control the metal ion cross-linked part, and therefore it is preferably 30% by mass or less.

As what is marketed, the following can be used, for example.
High Milan (registered trademark) AM7327, 185 manufactured by Mitsui DuPont Polychemical Co., Ltd.
5, 1856, 1554, 1555, 1557, 1605, 1706, 1707, AM7
311, AM7329, Iotech (registered trademark) 70 manufactured by ExxonMobil Chemical Co., Ltd.
10, 7030, 7510, 7520, 8000, 8030 and the like. They are,
It can be used alone or in combination of two or more.

The thickness of the first outer layer 4 is not particularly limited, but the thickness of the thinnest portion is 0.0.
It is preferably 9 mm or more, and more preferably 0.1 to 0.15 mm.

The first outer layer (insulating layer) 4 is most preferably formed using only an ionomer resin. However, as long as the effects of the present invention are exhibited, a resin composition in which other resins are added and mixed may be used. A resin composition containing 80% by mass or more of an ionomer resin is preferable, a resin composition containing 90% by mass or more is more preferable, and a resin composition containing 95% by mass or more is more preferable.

(Inner layer 3)
As shown in FIG. 1, the earphone cord 10 preferably has an inner layer (insulating layer) 3 that covers the conductor 2 inside the first outer layer 4. If the ionomer resin is coated directly on the conductor 2, the adhesion is too strong and it becomes difficult to peel the resin from the conductor 2.
It is preferable to provide the inner layer 3.

As the material of the inner layer 3, it is preferable to use a transparent or translucent resin so that the disconnection of the conductor 2 can be visually recognized from the outside. An ethylene-tetrafluoroethylene copolymer (ETFE)
In addition, it is preferable to use one or more selected from ethylene-α-olefin copolymers, and it is particularly preferable to use an ethylene-tetrafluoroethylene copolymer (ETFE) in terms of cost and transparency.

The thickness of the inner layer 3 is not particularly limited, but the thickness of the thinnest part is 0.05 mm.
It is preferable that it is above, and it is more preferable that it is 0.08-0.15 mm.

(Second outer layer 5)
As shown in FIG. 1, the earphone cord 10 preferably has a second outer layer (insulating layer) 5 that covers the first outer layer 4 in terms of human skin contact.

As the material of the second outer layer 5, it is preferable to use a transparent or translucent resin so that the disconnection of the conductor 2 can be visually recognized from the outside, and an ethylene-tetrafluoroethylene copolymer (ET
It is preferable to use one or more selected from FE), ethylene-α olefin copolymer and polyamide. The use of ethylene-tetrafluoroethylene copolymer (ETFE) is particularly preferable from the viewpoint of transparency, the ethylene-α olefin copolymer is excellent from the viewpoint of cost, and the polyamide is excellent from the viewpoint of flexibility. As the polyamide, for example, polyamide 6, polyamide 66, or an alloy thereof can be used.

The thickness (thickness) of the second outer layer 5 is preferably thin in terms of cost, and is 100 μm.
Or less, more preferably 10 to 80 μm, and more preferably 20 to 60 μm.
More preferably.

In addition, flame retardants, fillers, cross-linking agents, cross-linking aids, lubricants, antioxidants, plasticizers, etc. are appropriately added to the resin or resin composition that is the material of the inner layer and the first and second outer layers. May be.

〔earphone〕
An earphone according to an embodiment of the present invention includes the earphone cord according to the above-described embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of the earphone according to the embodiment of the present invention.
An earphone 100 according to an embodiment of the present invention includes an earphone cord 10 according to the above-described embodiment, an ear insertion portion 11 provided at one end of the earphone cord 10, and an earphone cord 10.
And a plug 12 provided at the other end. Various parts of known earphones can be adopted for portions other than the earphone cord 10.

[Effect of the embodiment of the present invention]
According to the present embodiment, by using an ionomer resin as the first outer layer, the earphone cord excellent in light resistance stability (particularly maintaining transparency with respect to visible light) and not easily scratched is provided. The provided earphone can be provided. Therefore, it is possible to provide an earphone cord excellent in disconnection visibility and an earphone including the earphone cord.

Moreover, according to the present embodiment, it is possible to provide an earphone cord with good human skin contact and an earphone provided with the earphone cord.

Conventionally, the polyvinyl chloride resin used for the insulating layer has a problem of generating a toxic gas such as hydrogen chloride at the time of combustion, but in this embodiment, it is not necessary to use the polyvinyl chloride resin. Therefore, it is possible to provide an earphone cord having no problem and an earphone including the earphone cord.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[Manufacture of earphone cords]
Linear aramid fiber (manufactured by Toray DuPont Co., Ltd., trade name: Kevlar (registered trademark) ((29
) 400D)), after winding 6 silver-plated annealed copper wires or tin-plated annealed copper wires with a diameter of 0.08 mm, 12 windings of the same annealed copper wire were wound on the outer circumference. Conductor 2
A conductor core made of

Next, ethylene-tetrafluoroethylene copolymer (ETFE) (manufactured by Asahi Glass Co., Ltd., trade name: ETFE C-88AXM) having a thickness of 0.09 mm (average minimum thickness 0.09 mm, partial minimum thickness 0. 085 mm) and an outer diameter of 0.65 mm, and the outer layer of conductor 2 (conductor core) was extrusion coated to form inner layer 3. Two of these were prepared and twisted with a pitch of 8 (mm) as a guide.

Next, for Examples 1 to 6 and Comparative Examples 1 and 2, the resins described in Tables 1 to 3 were average thickness 0.11 mm, partial minimum thickness 0.1 mm, outer diameter 1. The outer circumference of the inner layer 3 was adjusted to 6 mm and extrusion coated with a 40 mm extruder to form the first outer layer 4.

For Examples 7 to 10, the outer diameter was adjusted so that the average thickness of the first outer layer 4 was 0.11 mm and the thickness of the second outer layer 5 was 30 to 200 μm by a solid extrusion method using a two-layer head. Then, the following resin was extrusion coated on the outer periphery of the inner layer 3 with a 40 mm extruder to form the first outer layer 4 and the second outer layer 5.
First outer layer 4: Resins described in Tables 1 and 2. Second outer layer 5: Examples 7 to 9 are ethylene-tetrafluoroethylene copolymer (ETFE) (Asahi Glass Co., Ltd., trade name: ETFE C-88AXM), Example 10 is a polyamide-based resin (manufactured by EMS-CHAMIE, trade name: Grilon CF-6S)

  Material No. 1 of the first outer layer 4 The flexural modulus of 2 to 5 was measured using JISK7106.

The working conditions for coating the first outer layer 4 are as follows.
Cylinder 1: 130 ° C
Cylinder 2: 165 ° C
Cylinder 3: 180 ° C
Head: 180 ° C, Die: 180 ° C
Rotation speed: 20rpm, Linear speed: 12m / min

The working conditions for coating the second outer layer 5 are as follows.
Cylinder 1: 280 ° C
Cylinder 2: 290 ° C
Cylinder 3: 300 ° C
Head: 310 ° C, Die: 310 ° C
Rotation speed: 0-20rpm, Linear speed: 12m / min

[Evaluation of earphone cord]
The manufactured earphone cord and the resin cord described later were evaluated by the following method.
The evaluation results are shown in Tables 2-3.

(Light resistance)
Using a metal halide lamp type weather resistance tester, 40 ° C., humidity 50%, illuminance 1.5 KW / m
Irradiate the earphone cord under the condition of ² and expose it for 72 hours or more, then visually change the hue (yellowing)
The presence or absence of was observed. No change in hue (yellowing) and the initial transparency maintained as ◎, no change in hue (yellowing) but very slight change in transparency as ○, hue change (yellowing) What existed was made into x.

(Disconnection visibility)
A 150 mm long sample is made from the manufactured earphone cord, and this is room temperature, 200 m
The device was stopped when it was pulled and disconnected. ◎ indicates that the conductor has been visually confirmed from the outside, and ◎ indicates that the conductor has been disconnected from the outside using a 5x magnifier, and ○ indicates that the conductor is disconnected even if a 5x magnifier is used. Was not confirmed from outside.

(Scratch property)
Using a wear tester with a file length of 25 mm / count, a 150-count test was performed with a 450 g load on the resin string produced as described below, and scratch resistance was determined. When the value of [diameter of resin string after test / diameter of resin string before test] is 0.6 or more, ◎, 0.5 or more and 0
. Those less than 6 were rated as ◯, and those less than 0.5 as x.
<Resin string>
Using the resins described in Tables 1 to 3, the outer diameter (diameter) is 2.2 mm under the same temperature condition (rotation speed: 20 rpm) as in the case of coating the second outer layer 5 with a 20 mm extruder. By working at an extrusion speed of 5 m / min, resin strings of Examples 1 to 9 and Comparative Examples 1 and 2 were produced.

(Human skin contact)
A 60 cm long sample was cut from the resin string produced as described above, and both ends were connected with vinyl tape, and a circular shape was put on the neck and exposed to human skin at 23 ° C. and 50% humidity for 72 hours. . If itchy or no skin redness is judged as ○,
Or the thing with redness of the skin was determined as x. Among those determined to be ○, even in the summer (30 ° C, humidity 80% average), in an environment with sweating, for 1 hour continuously,
A sample that did not feel uncomfortable and had no change in the gloss of the resin surface was marked with ◎. Further, among those judged as ◯, △ was given to the neck and felt uncomfortable due to hardness.

Examples 1-10 satisfied all the performances. As can be seen from a comparison between Examples 1-2 and 3-6, the material No. having a flexural modulus in the range of 30-50 MPa was used. 2 using material No. 2 which is out of the same range. The light-resistant stability was more excellent than that using 3-5. Further, as can be seen from the comparison between Examples 4 and 5, in the case where the conductor plating was made of silver, the disconnection visibility was easier to judge than in the case of plating with tin. It is considered that metal ion species are also affecting the difference in the above effects, and Zn is presumed to be preferable.

Regarding the human skin contact properties of Examples 3, 6 and 9, itching and redness of the skin were not seen, but a slight sense of incongruity due to hardness was felt. This is considered to be due to the bending elastic modulus of the ionomer resin for Examples 3 and 6 and the thickness of the second outer layer 5 of the ionomer resin for Example 9. On the other hand, about Example 10, the human skin contact property which is inferior to Examples 7 and 8 was obtained. This is presumably because polyamide was excellent in flexibility, so that it was not uncomfortable even when it was thick.

On the other hand, Comparative Examples 1 and 2 using PVC as the material of the first outer layer 4 did not provide satisfactory results in light resistance stability, disconnection visibility, and scratch resistance.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible.

1: aramid fiber, 2: conductor, 3: inner layer 4: first outer layer, 5: second outer layer 10: earphone cord, 11: ear insertion portion, 12: plug 100: earphone

Claims (6)

And the conductor, covered around the conductor, a first outer layer using an ionomer resin possess,
The flexural modulus of the ionomer resin is 30-50 MPa,
An earphone cord capable of confirming the conductor from the outside . Ri metal ionic species Zn der contributes to intermolecular bonding of the ionomer resin,
The earphone cord according to claim 1, wherein the conductor is a silver-plated conductor . A second outer layer covering the first outer layer, wherein the second outer layer comprises at least one selected from an ethylene-tetrafluoroethylene copolymer (ETFE), an ethylene-α-olefin copolymer, and a polyamide ; The earphone cord according to claim 1 , wherein the earphone cord is formed by using the earphone cord. The earphone cord according to claim 3 , wherein a thickness of the second outer layer is 100 µm or less. Has an inner layer covering the conductor on the inner side of the said first outer layer, the inner layer is an ethylene - with tetrafluoroethylene copolymer (ETFE), and one or more selected ethylene -α-olefin copolymer or al The earphone cord according to any one of claims 1 to 4 , wherein the earphone cord is formed. An earphone comprising the earphone cord according to any one of claims 1 to 5 .