JP2003346563A - Flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat cable having sufficient flame retardancy and adhesiveness as well as excellent dielectric property. <P>SOLUTION: This flat cable is integrally formed by sandwiching insulating core wires 11 with adhesive films 14. An insulator 13 of the insulating core wire 11 is composed of a resin composition having a dielectric constant of 3 or less comprising nonpolar polymer such as polyethylene of 100 weight part, and a nonhalogen frame-retardant such as magnesium hydroxide of 10-50 weight part. An adhesive layer 16 of the adhesive film 14 is composed of a flame- retardant adhesive admixture comprising a polyester resin having a glass transition temperature of -70-10°C and a molecular weight of 5,000-40,000 of 100 weight part, a nonhalogen flame-retardant such as melamine cyanurate of 30-250 weight part, titanium oxide-coated red phosphorus of 1-50 weight part, and zinc hydroxystannate having a particle diameter of 10 μm or less of 1-50 weight part. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat cable used for internal wiring of electronic equipment, electric equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a flat cable as shown in FIG. 2 has been known. In FIG. 2, reference numeral 1 denotes a rectangular conductor. A plurality of the rectangular conductors 1 are sandwiched between two adhesive films 2 and 2 to be integrated into a flat cable. The adhesive film 2 is obtained by forming an adhesive layer 4 on one surface of a base film 3 made of a plastic film such as polyethylene terephthalate or polyimide.

In a flat cable having such a structure,
Because of high density wiring, it is widely used for high density wiring inside computer equipment, audio equipment, video equipment and the like. By the way, in such a flat cable, since the rectangular conductor 1 is surrounded by the adhesive layer 4, the adhesive layer 4 functions as an insulator of the rectangular conductor 1.

For the adhesive layer 4, an adhesive mixture containing a polyester resin such as a copolymerized polyester as a base polymer is mainly used from the viewpoint of adhesiveness. Normal,
Since the polyester resin contains many polar groups such as an ester group and a carboxyl group in the molecule, the dielectric constant is high, the dielectric constant of the adhesive layer 4 is also high, and the dielectric properties as a flat cable are reduced. Become.

[0005] In particular, when such a flat cable is required to have flame retardancy from the viewpoint of disaster prevention, the adhesive layer 4 is also required to have flame retardancy, and the polyester resin of the base polymer has various flame retardants. A mixture containing a flame retardant will be used. However, since all ordinary flame retardants have a polar group in the molecule, the dielectric constant of the flame-retarded adhesive layer 4 is further reduced, and the dielectric properties as a flat cable are also large. descend.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to obtain a flat cable exhibiting sufficient flame retardancy and adhesiveness and having excellent dielectric properties.

[0007]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 is a flat cable in which an insulated wire is sandwiched between adhesive films, wherein the insulator of the insulated wire is made of an insulator. A resin composition obtained by mixing 10 to 50 parts by weight of a non-halogen flame retardant with 100 parts by weight of a non-polar polymer, wherein the adhesive layer of the adhesive film comprises 100 parts by weight of a polyester resin and 30 to 250 parts by weight of a non-halogen flame retardant. A flat cable comprising a flame-retardant adhesive mixture containing 1 to 50 parts by weight of titanium oxide-coated red phosphorus and 1 to 50 parts by weight of zinc hydroxystannate.

According to a second aspect of the present invention, there is provided the flat cable according to the first aspect, wherein the resin composition forming the insulator of the insulated wire has a dielectric constant of 3 or less. According to a third aspect of the present invention, the polyester resin forming the flame-retardant adhesive mixture has a glass transition temperature of -70 to 10 ° C and a molecular weight of 5
The flat cable according to claim 1, wherein the number is from 000 to 40,000. The invention according to claim 4 is the flat cable according to claim 1, wherein the flame-retardant adhesive mixture contains silica.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on its embodiments. FIG. 1 shows an example of the flat cable of the present invention, and reference numeral 11 in the figure denotes an insulated wire core. The insulated wire core 11 includes a round conductor 12 and
And an insulator 13 covering the conductor 12.

[0010] As the conductor 12, a conductor having an outer diameter of about 0.3 mm, such as a soft copper stranded wire or a single copper wire, is mainly used.
The insulator 13 is made of a flame-retardant resin composition having the following composition, and has a thickness of about 0.15 mm in which the resin composition is coated on the conductor 12 by a known extrusion coating method.

As the resin composition, a resin composition containing a low-polarity polymer and a non-halogen flame retardant as essential components is used. Here, the low-polarity polymer refers to a polymer having a dielectric constant of 2.5 or less, specifically, a polymer having almost no polar group in the molecule, for example, high-density polyethylene, low-density polyethylene, and ultra-low-density polyethylene. Polyethylene such as polyethylene and linear low-density polyethylene, polypropylene, ethylene-propylene rubber, polystyrene-poly (ethylene-butylene) -polystyrene block copolymer, polystyrene-poly (ethylene-
One or more blend polymers such as thermoplastic elastomers such as propylene) / polystyrene block copolymer, hydrogenated styrene-butadiene rubber, and CEBC.

As the non-halogen flame retardant compounded in the low-polarity polymer, a nitrogen-containing organic flame retardant, a phosphorus-based flame retardant, a metal hydroxide, a boric acid compound and the like are used. Specific examples of the nitrogen-containing organic flame retardant include one or more of cyanuric acid triamide, cyanuric acid diamide, cyanuric acid monoamide, melam, melamine cyanurate, melamine resin, homoguanamine, benzoguanamine, acetoguanamine and the like. A mixture is used.

As the phosphorus-based flame retardant, one or a mixture of two or more of tricresyl phosphate, triphenyl fuphosphate, ammonium polyphosphate and the like is used. As the metal hydroxide, one kind or a mixture of two or more kinds such as magnesium hydroxide, aluminum hydroxide, and calcium hydroxide is used. As the boric acid compound, zinc borate or the like is used.

These non-halogen flame retardants are coated with a titanate coupling agent, a silane coupling agent such as vinyl silane, amino silane or mercapto silane, or a higher fatty acid such as stearic acid or oleic acid in order to enhance the affinity with a low-polarity polymer. It is preferable to use the treated one.

The compounding amount of the non-halogen flame retardant is 10 to 50 parts by weight based on 100 parts by weight of the low-polarity polymer. When the amount is less than 10 parts by weight, the flame retardancy is insufficient. Becomes large, the dielectric constant exceeds 3, and the dielectric properties of the insulated wire core 11 decrease. If necessary, a processing aid such as stearic acid may be added to the resin composition in an amount of about 0.5 to 1 part by weight based on 100 parts by weight of the low-polar polymer, and an anti-aging agent such as a phenolic anti-aging agent may be reduced. You may add about 0.1-0.3 weight part with respect to 100 weight part of polar polymers.

The resin composition having such a composition must have a dielectric constant of 3 or less as the resin composition. If the dielectric constant exceeds 3, the dielectric properties of the flat cable deteriorate. Dielectric constant of 3
The following can be achieved by appropriately selecting and using the types and blending amounts of the low-polarity polymer and the non-halogen flame retardant.

A plurality of the insulated wire cores 11 are sandwiched between two adhesive films 14 and 14 and are integrated under pressure to form a flat cable of this example. The adhesive film 14 has a thickness of 10 to 100 μm on one surface of a base film 15 having a thickness of 10 to 200 μm made of a plastic such as a saturated polyester such as polyethylene terephthalate and polyethylene naphthalate, polyimide, polyphenylene sulfide, polyethylene, polypropylene and polyamide. The adhesive layer 16 is formed.

The adhesive layer 16 comprises 100 parts by weight of a polyester resin and 30 to 25 non-halogen flame retardants.
0 part by weight, 1 to 50 parts by weight of titanium oxide-coated red phosphorus, and 1 to 50 parts by weight of zinc hydroxystannate as an essential component.

Hereinafter, the flame-retardant adhesive mixture will be described. As a polyester resin serving as a base resin in the flame-retardant adhesive mixture, for example, the glass transition temperature thereof is-
70 to 10 ° C. and a molecular weight of 5000 to 4000
A polyester resin containing at least one polyester resin having a glass transition temperature and a molecular weight other than 0 may be mixed. The molecular weight in the present invention is represented by a weight average molecular weight.

Specific examples of the polyester resin include acid components such as terephthalic acid, isophthalic acid, diphenylcarboxylic acid, adipic acid and sebacic acid;
Ethylene glycol, 1,4-butanediol, 1,4
Various saturated polyesters and saturated copolymerized polyesters obtained by a known condensation polymerization method using alcohol components such as dialcohols such as dicyclohexane dimethylol and diethylene glycol as raw materials are used.

The glass transition temperature of the polyester resin is such that the acid component and the alcohol component are each 1
By properly combining the species or more, this is -70 to
It can be adjusted to the range of 10 ° C. In addition, the molecular weight, various polymerization conditions during the polycondensation reaction of the acid component and the alcohol component, for example, polymerization temperature, polymerization time, polymerization pressure,
By properly adjusting the polymerization catalyst and the like,
It can be set in the range of 0 to 40000.

In this polyester resin, if the glass transition temperature is lower than -70 ° C., blocking tends to occur, and if it exceeds 10 ° C., the adhesive strength decreases. On the other hand, if the molecular weight is less than 5,000, it becomes brittle, and if it exceeds 40,000, it becomes hard and the flexibility deteriorates.

As the non-halogen flame retardant, a nitrogen-containing organic flame retardant or the like is used. This nitrogen-containing organic flame retardant is a non-halogen flame retardant and does not lower its electric resistance when used as an adhesive layer. Specific examples of such nitrogen-containing organic flame retardants include one or two of cyanuric acid triamide, cyanuric acid diamide, cyanuric acid monoamide, melam, melamine cyanurate, melamine resin, homoguanamine, benzoguanamine, acetoguanamine and the like. Mixtures of more than one species are used.

Of these, melamine cyanurate is particularly preferred from the viewpoints of dispersibility, mixing properties, adhesiveness, and the like with respect to a polyester resin. Furthermore, the surface is silica,
Nitrogen-containing organic flame retardants that have been surface-treated by coating with inorganic fine particles such as are preferred because of their high dispersibility in polyester resins.

The amount of such a non-halogen flame retardant is determined depending on the type of flame retardant to be used, the required flame retardancy, etc., but is usually 30 to 250 parts by weight based on 100 parts by weight of the polyester resin. When the amount is less than 30 parts by weight, the flame retardancy of the obtained flame-retardant adhesive mixture is insufficient, and when it exceeds 250 parts by weight, the adhesive strength is reduced, and the flexibility when the adhesive layer 16 is formed is also reduced.

Titanium oxide-coated red phosphorus means that the surface of red phosphorus particles having a particle size of 1 to 20 μm has a thickness of 1 nm.
One coated with a thin film of titanium oxide of 10 to 10 μm and having an average particle diameter of 1 to 25 μm is used. The proportion of red phosphorus in the titanium oxide-coated red phosphorus is 10 to 50% by weight, and if it is less than 10% by weight, the flame retardant effect is insufficient, and if it exceeds 50% by weight, coloring becomes severe.

The titanium oxide coating red phosphorus scatters the incident light by transmitting or refracting the light through the titanium oxide thin film on the surface due to the presence of the titanium oxide thin film on the surface, and disperses the light in the resin. In this case, light transmittance is exhibited. Also, when placed under high temperatures such as during combustion, red phosphorus inside volatilizes, destroys the coating film, and squirts and diffuses to the outside to exhibit the inherent flame retardancy of red phosphorus.

[0028] The compounding amount of the titanium oxide-coated red phosphorus is 1 to 5 with respect to 100 parts by weight of the polyester resin.
When the amount is less than 1 part by weight, the flame retardant effect is not obtained, and when the amount exceeds 50 parts by weight, the coloring of the adhesive layer 16 becomes intense. In addition, the titanium oxide-coated red phosphorus imparts good flame retardancy, so that by blending the same, the amount of the non-halogen flame retardant can be reduced, and the decrease in adhesive strength due to the non-halogen flame retardant can be suppressed. I can do it.

Zinc hydroxystannate used in the flame-retardant adhesive mixture functions as an adhesion promoter and a flame retardant aid, and has an average particle size of 1 in consideration of dispersibility.
Particles of 0 μm or less are used. The amount of the zinc hydroxystannate is 1 to 50 parts by weight with respect to 100 parts by weight of the polyester resin. When the amount is less than 1 part by weight, the effect of increasing the adhesive strength is not obtained. I do. In addition, since zinc hydroxystannate simultaneously imparts flame retardancy, by blending the same, the amount of the flame retardant can be reduced, and a decrease in adhesive strength due to the blend of the flame retardant can be suppressed.

Further, silica or the like can be added as a filler to the above flame-retardant adhesive mixture. By adding about 5 parts by weight of silica to 100 parts by weight of the polyester resin, the blocking property is improved. In addition, it is possible to prevent the adhesive layer 16 from remaining on the base film 15 due to the adhesive residue.

Further, within a range that does not impair the effects of the present invention,
The flame-retardant adhesive mixture further contains various additives such as an organic solvent, an antioxidant, a coloring agent, various coupling agents,
A crosslinking agent, a crosslinking assistant, and an antistatic agent may be appropriately added.
Examples of the organic solvent include ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, and aromatics such as toluene.

The flame-retardant adhesive mixture is composed of 100 parts by weight of a polyester resin, 30 to 250 parts by weight of a halogen-free flame retardant, 1 to 50 parts by weight of titanium oxide-coated red phosphorus, and 1 to 50 parts by weight of zinc hydroxystannate. If necessary, it can be produced by uniformly mixing with other additive components. The flame-retardant adhesive mixture preferably has an oxygen index of 25 or more, a volume resistivity of 1 × 10 ¹⁵ Ω · cm or more, and a polyethylene terephthalate film having a thickness of 25 μm. It is preferable that the mold peeling strength (peeling speed 300 mm / min) is 0.5 kgf / cm or more.

The form of the flame-retardant adhesive mixture may be in the form of a solution, paste, pellet, or the like. To form the adhesive layer 16 in the adhesive film 14 forming a flat cable, In general, pellets are extruded from an extruder onto the base film 15 and used to form a film, in addition to being applied to the base film 15.

The flat cable of the present invention uses the adhesive film 14 formed as described above,
It is manufactured by pressing the insulating wire core 11 with a pressing roll, a pressing press or the like, and simultaneously heating to a temperature of 80 to 200 ° C. at this time. Generally, a method of using a heating / pressing roll and continuously bonding is widely used in terms of workability and the like.

In such a flat cable,
Insulator 1 in which conductor 12 is made of a resin composition having a dielectric constant of 3 or less
3, so that it has good dielectric properties. For this reason, as the flame-retardant adhesive mixture forming the adhesive layer 16 of the adhesive film 14, a material having sufficient flame retardancy and adhesiveness irrespective of the dielectric properties can be used, and a highly difficult flat cable can be used. Flammability and adhesiveness can be obtained.

Since the adhesive layer 16 contains titanium oxide-coated red phosphorus as a flame retardant, the adhesive layer 16 can be provided with high flame retardancy and the adhesive layer 16 is colored deep red-brown. The inspection of the product of the flat cable using the optical sensor is not hindered.

Further, since the titanium oxide-coated red phosphorus imparts high flame retardancy, the amount of the non-halogen flame retardant can be reduced, and the decrease in adhesiveness can be suppressed. In addition, since zinc hydroxystannate is blended, good adhesiveness is obtained, and at the same time, since it has a flame retardant effect, the blending amount of the non-halogen flame retardant can be reduced, which also suppresses a decrease in adhesiveness. Furthermore, since the insulator 13 and the adhesive layer 16 do not contain a halogen element, even if this flat cable is incinerated, no harmful halogen-containing gas is generated. For this reason, this flat cable can be used for wiring of computer equipment and the like that require excellent dielectric properties, high adhesiveness, and good flame retardancy that meets UL standard HB class.

Hereinafter, specific examples will be described. A resin composition forming the insulator 13 and a flame-retardant adhesive mixture forming the adhesive layer 16 having the composition (parts by weight) shown in Tables 1 to 3 were prepared.
The resin composition constituting the insulator 13 was extruded with an outer diameter of 0.1 mm by an extruder.
It was extrusion-coated on a 3 mm soft copper stranded wire to obtain an insulated wire core 11 having an insulator 13 having a thickness of 0.15 mm.

On the other hand, the flame-retardant adhesive mixture forming the adhesive layer 16 was dissolved in a mixed solvent consisting of 1 part by volume of methyl ethyl ketone and 4 parts by volume of toluene to prepare a solution type adhesive having a resin content of 30 wt%. This solvent-type adhesive was applied on a 25 μm-thick polyethylene terephthalate film with a bar coater and dried to form an adhesive layer having a thickness of 35 μm, thereby forming an adhesive film 14.

Two adhesive films 14 were used, and five insulated wires 11 were sandwiched between them in a state of being parallel to each other. The bonding speed was 0.5 m / min, the temperature was 160 ° C., and the pressure was 1.
At 0 MPa, they were bonded to form a flat cable. The flat cable was evaluated for flame retardancy, dielectric constant of insulator, oxygen index of adhesive layer, adhesion, and hue.

The flame retardancy was evaluated by performing a flame retardancy test of the HB class of the UL standard.
And The dielectric constant of the insulator was measured by using a dielectric constant measuring device after removing the insulator by peeling it off. The oxygen index of the adhesive layer is measured by a flame retardant oxygen index measuring device,
Those with an oxygen index of 25 or more were rated as ○, and those with an oxygen index less than 25 were rated as x.

The T-peel strength of the flat cable was measured, and the adhesive strength was evaluated as ○ when the peel strength was 0.5 kgf / cm or more, and as × when the peel strength was less than 0.5 kgf / cm. When the flat cable was inspected with an optical sensor, the inspection light was transmitted through the flat cable and the hue was evaluated as good when the inspection was performed, and x when the inspection was not performed.

In Tables 1 to 3, "low-polarity polymer" refers to ultra-low-density polyethylene having a dielectric constant of 2.38, a density of 0.88 g / cm ³ , and a melt flow rate 1 (trade name "DFDA117" manufactured by Nippon Unicar Co., Ltd.). ")," Halogen-free flame retardant A "is magnesium hydroxide (manufactured by Kyowa Chemical Co., Ltd., trade name" Kisma 5A "), and" Anti-aging agent "is phenolic anti-aging agent (manufactured by Ciba Specialty Chemicals). , Trade name “Irganox 1010”).

The “polyester resin” has a glass transition point of 7
C., polyester resin having a molecular weight of 23,000 (manufactured by Toyobo Co., Ltd., trade name "Vylon 300"), "Non-halogen flame retardant B" is melamine cyanurate (Nissan Chemical Industries, trade name "MC610", "Red phosphorus" is 75w red phosphorus
t% (manufactured by Rin Kagaku Kogyo Co., Ltd., trade name “NOVARED 120UF”).

"Titanium oxide-coated red phosphorus" refers to a product having a red phosphorus content of 31.5% by weight (trade name "NOVA Red 280C" manufactured by Rin Kagaku Kogyo KK), and "zinc hydroxystannate" refers to a particle having a particle size of 5 μm. The product (manufactured by Nippon Chemical Industry Co., Ltd., trade name “Zinc Hydroxystannate”), and the “filler” refers to silica having a particle size of 1.8 μm (manufactured by Nippon Aerosil Co., Ltd., trade name “Aerosil 300”). The results are shown in Tables 1 to 3.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

From the results shown in these tables, 10 to 50 parts by weight of a non-halogen flame retardant such as magnesium hydroxide was mixed with 100 parts by weight of a low-polarity polymer such as polyethylene as the resin composition forming the insulator 13 of the insulated wire core 11. As a flame-retardant adhesive admixture forming the adhesive layer 16 of the adhesive film 14, 100 parts by weight of a polyester resin was used to prepare a non-halogen flame retardant such as melamine cyanurate.
By using a mixture of 50 parts by weight, 1 to 50 parts by weight of titanium oxide coated red phosphorus and 1 to 50 parts by weight of zinc hydroxystannate, a flat cable having excellent flame retardancy, adhesiveness, hue, and dielectric properties can be obtained. It can be seen that it can be obtained.

[0050]

As described above, the flat cable of the present invention exhibits a high adhesive strength, has excellent flame retardancy, exhibits good dielectric properties, and has a light color and transparent hue. Therefore, the product inspection can be performed by the optical sensor.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a flat cable according to the present invention.

FIG. 2 is a schematic sectional view showing an example of a conventional flat cable.

[Explanation of symbols]

11: Insulated wire core, 13: Insulator, 14: Adhesive film, 16: Adhesive layer.

Claims (4)

[Claims] 1. A flat cable in which an insulated wire core is sandwiched between adhesive films, wherein the insulator of the insulated wire wire is composed of 100 parts by weight of a nonpolar polymer and 10 to 50 parts by weight of a non-halogen flame retardant. The adhesive layer of the adhesive film is made of a polyester resin 100
Parts by weight, 30 to 250 parts by weight of a non-halogen flame retardant,
A flat cable comprising a flame-retardant adhesive mixture containing 1 to 50 parts by weight of red phosphorus containing titanium oxide and 1 to 50 parts by weight of zinc hydroxystannate. 2. The flat cable according to claim 1, wherein the resin composition forming the insulator of the insulated wire has a dielectric constant of 3 or less. 3. The polyester resin constituting the flame-retardant adhesive mixture has a glass transition temperature of -70 to 10 ° C. and a molecular weight of 5,000.
3. The method of claim 1, wherein
The described flat cable. 4. The flat cable according to claim 1, wherein the flame-retardant adhesive mixture contains silica.