JPH05217430A - Non-halogen flame retardant flat cable - Google Patents

Abstract

PURPOSE:To provide flame retardation capable of passing the test VW-1 of UL standard by using for an insulating film a film made of aromatic polymer which contains an aromatic ring in the molecular structure without containing halogen and has a critical oxygen index of not less than a specific value. CONSTITUTION:A plurality of conductors 3 is put in parallel between a couple of insulating base materials 4 including an insulating film layer 1 and an adhesive layer 2 and thermal fusion is carried out to form a flat cable. In the non- halogen flame retardant flat cable, the insulating film layer 1 is formed out of an aromatic polymer which contains an aromatic ring in the molecular structure without containing halogen and has a critical oxygen index of not less than 30%. In this cable, the adhesive layer consists of a composition which contains metal hydrate of 50 to 200 pts.wt. relative to base polymer of 100 pts.wt. without containing halogen compounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat cable (flat electric wire) used for wiring of electric / electronic devices, and more particularly to a non-halogen flame-retardant flat cable having excellent flame retardancy and containing no halogen. ..

[0002]

2. Description of the Related Art In response to the complicated wiring in various devices due to the recent development of the semiconductor industry, video equipment, audio equipment, office automation equipment, and computers are used to save wiring work and prevent miswiring. A flat multi-core cable is used as an electric wire for internal wiring of devices, robots, ultrasonic diagnostic equipment, and the like.

A flat cable is generally manufactured by sandwiching a plurality of conductors in parallel between two insulating base materials, heat-sealing the insulating base materials, and integrating them.
As the insulating substrate, a two-layer structure having a biaxially stretched polyethylene terephthalate (PET) film layer having excellent mechanical properties and electrical properties and an adhesive layer for heat-sealing it has been widely used. It was As the base polymer of the adhesive layer, polyethylene (PE), polyvinyl chloride (PV
C), thermoplastic saturated copolyester, thermosetting polyester and the like are widely used.

Such a flat cable has an application requiring a high degree of flame retardancy, and a flame retardancy test such as the vertical flame retardancy test of the UL standard in the United States is defined. Conventionally,
In order to satisfy these flame-retardant standards, it has been carried out to add flame retardants containing halogens such as bromine and chlorine in the molecule such as decabromodiphenyl ether and hexabromodiphenyl ether to the base polymer of the adhesive layer. ing. However, when a flat cable containing a flame retardant containing halogen burns due to a fire or the like, a toxic gas containing halogen is generated, which may hinder evacuation or fire extinguishing activities.

In order to produce a flame-retardant flat cable using an insulating substrate containing no halogen,
It is conceivable to use a highly flame-retardant engineering plastic such as polyimide as the insulating film.
However, a flat cable using polyimide as an insulating film has an extremely thick insulating film (exceeding 50 μm).
In some cases, or the thickness of the adhesive layer is extremely thin (25 μm
However, in other cases, there was a problem that it did not pass the judgment level VW-1 (hereinafter abbreviated as VW-1 test) of the UL standard vertical flame retardancy test. .. If the insulating film is too thick, the flexibility may be impaired, and if the adhesive layer is too thin, it is difficult to sufficiently heat-bond a plurality of conductors.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flame-retardant flat cable which passes the VW-1 test by using an insulating base material containing no halogen. As a result of diligent research, the inventors of the present invention have an aromatic ring in the molecular skeleton, do not contain halogen, and have a limiting oxygen index of 3
By using a film formed of 0% or more of an aromatic polymer as an insulating film and using an adhesive composition in which a large amount of a metal hydrate is mixed with a base polymer for an adhesive layer, halogen-free Nevertheless V
It has been found that a flat cable excellent in flame retardance that passes the W-1 test can be obtained. The present invention has been completed based on these findings.

[0007]

Thus, according to the present invention, a plurality of conductors are arranged in parallel between two insulating base materials having an insulating film layer and an adhesive layer, with each adhesive layer inside. In the flat cable formed by sandwiching and heat-sealing, the insulating film layer of the insulating base material has an aromatic ring in the molecular skeleton, does not contain halogen, and has an oxygen index of 30% or more. And a adhesive layer containing a metal hydrate in an amount of 50 to 200 parts by weight based on 100 parts by weight of a base polymer and comprising a halide-free composition. A featured non-halogen flame retardant flat cable is provided.

The present invention will be described in detail below. In the present invention, a film made of an aromatic polymer having an aromatic ring in the molecular skeleton, containing no halogen, and having a limiting oxygen index of 30% or more is used as the insulating film of the flat cable. The limiting oxygen index is the minimum concentration (% by volume) of oxygen required for an ignited sample to continue burning in a mixed air flow of oxygen and nitrogen. ASTM D2863-
It means the value measured by the test method specified in 87. A material having a larger limiting oxygen index is evaluated to be a material that is less likely to burn, and when the value is 30% or more, the material has high flame retardancy.

As such an aromatic polymer, those known as engineering plastics can be used, and specifically, polyimide, polyparabanic acid, wholly aromatic holamide, wholly aromatic polyester, polyether ether ketone, polyether. Examples thereof include ketones, polyphenylene sulfides, polyether sulfones, polyether imides, polysulfones, and polyarylates.

The base polymer used in the adhesive layer is, for example, polyethylene, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, or polyolefin hot polymer obtained by graft-copolymerizing a monomer having a functional group. Thermoplastic resins such as melt resins, saturated copolyesters, polyester elastomers, polyurethane elastomers; thermosetting resins such as epoxy resins, urethane resins, unsaturated polyesters, phenol resins and the like can be mentioned.

Examples of metal hydrates added to these base polymers include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, barium hydroxide,
Examples thereof include tin oxide hydrate and basic magnesium carbonate. The addition ratio of metal hydrate is 100% based on the base polymer.
50 to 200 parts by weight, preferably 80 to 200 parts by weight
It is 150 parts by weight. If this ratio is less than 50 parts by weight, sufficient flame retardancy cannot be imparted, and if it exceeds 200 parts by weight, the elongation of the resin composition decreases, so that bending tends to cause cracking.

If necessary, a halogen-free antioxidant, a filler, a coloring agent, a crosslinking agent, a crosslinking auxiliary agent, etc. can be appropriately added to the resin composition of the adhesive layer of the present invention. ..

Further, when the base polymer used for the adhesive layer is a thermoplastic resin, a plurality of conductors are sandwiched between two insulating base materials and laminated, and then the resin composition is cured by irradiation with ionizing radiation. If so, a flat cable having higher heat resistance can be obtained. The type of ionizing radiation is α
Rays, β rays (electron rays), γ rays, ultraviolet rays, X rays and the like can be used, but from the viewpoint of industrial use, it is preferable to use β rays or γ rays. Generally, the irradiation dose of ionizing radiation is preferably about 1 to 50 Mrad.

In the present invention, as a method for producing an insulating base material, for example, there is a method of laminating an adhesive composition on an insulating film made of an aromatic polymer by an extrusion coating method. The thickness of the insulating film is 10-5
About 0 μm is preferable. The thickness of the adhesive layer is usually 25
˜150 μm, preferably about 50 to 100 μm.

In order to produce a flat cable using the insulating base material of the present invention, a plurality of conductors are arranged in parallel between two insulating base materials with each adhesive layer inside, by a conventional method. It may be sandwiched and heat-sealed. The flat cable of the present invention is
Since neither the insulating film nor the adhesive layer contains halogen, there is no possibility of producing toxic hydrogen halide even when burned by a fire or the like, and it is highly flame-retardant.

[0016]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Examples 1 to 11 and Comparative Examples 1 to 4] A method for producing a flat cable sample will be described with reference to FIGS. 1 and 2. Using the materials shown in Table 1,
The adhesive layer (2) was coated on the insulating film (1) with a T-die extruder to prepare an insulating base material (4).
On the adhesive layer of the obtained insulating base material, a width of 1 mm and a thickness of 0.
Ten 5 mm tin-plated soft conductors (3) were arranged in parallel at 0.5 mm intervals, and another insulating base material was placed on top of it so that the adhesive layers were joined together, and this was thermocompression bonded. To produce a flat cable having a cross section as shown in FIG. In addition, from both sides of these flat cables,
An electron beam with an accelerating voltage of 1.0 MeV was irradiated at 10 Mrad.

The flat cable sample thus obtained was evaluated as follows. The results are shown in Table 1. (1) Flame retardancy Flame retardancy was tested and evaluated according to UL standard (VW-1 test). (2) Generation of Halogen The gas generated during combustion was qualitatively analyzed by gas chromatography to check whether halogen gas was generated. (3) Bending at 180 ° The presence or absence of cracks when the insulating substrate was bent at 180 ° was examined.

[0019]

[Table 1]

(Footnote) PI: Polyimide (limit oxygen index 53%) PEI: Polyetherimide (limit oxygen index 47%) PES: Polyether sulfone (limit oxygen index 38)
%) PPS: polyphenylene sulfide (limit oxygen index 4)
4%) PET: biaxially oriented polyethylene terephthalate EEA: ethylene / ethyl acrylate copolymer (ethyl acrylate content = 19% by weight, MI = 25)

As is clear from Table 1, the flat cables of the present invention (Examples 1 to 11) all passed the UL standard VW-1 test, no halogen gas was generated, and after bending 180 °. There was no crack. On the other hand, when the flame retardant is not used (Comparative Example 1) and the addition ratio of magnesium hydroxide is small (Comparative Example 2)
All failed the VW-1 test. When a large amount of magnesium hydroxide is added (Comparative Example 3), V
Although it passed the W-1 test, cracking occurred when the insulating base material was bent. PET is used for the insulating film,
When decabromodiphenyl ether was added as a flame retardant (Comparative Example 4), the VW-1 test was passed, and 180
There was no cracking of the insulating substrate due to bending, but halogen gas was generated during combustion.

[0022]

Industrial Applicability According to the present invention, it is possible to provide a flat cable which has flame retardance capable of passing the UL standard VW-1 test and which does not generate halogen gas during combustion. Therefore, it is effective in preventing the generation of toxic gas when a fire occurs.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating a method for laminating a non-halogen flame-retardant flat cable according to the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of a halogen-free flame-retardant flat cable of the present invention.

[Explanation of symbols]

 1 Insulating film 2 Adhesive layer 3 Conductor (plural) 4 Insulating base material

Claims (1)

[Claims] 1. A flat cable in which a plurality of conductors are sandwiched in parallel with each adhesive layer inside and sandwiched between two insulating base materials having an insulating film layer and an adhesive layer and heat-sealed. In the above, the insulating film layer of the insulating base material is a film formed of an aromatic polymer having an aromatic ring in the molecular skeleton, containing no halogen, and having a limiting oxygen index of 30% or more, A non-halogen flame-retardant flat cable, characterized in that the agent layer comprises a halide-free composition containing 50 to 200 parts by weight of a metal hydrate with respect to 100 parts by weight of a base polymer.