JPH10323954A - Film for flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fire resistance on the external surface, and at the same time, manufacture a film for flat cable by an easier process by a method wherein as the outermost layer, a fire-resistant insulating resin layer comprising a polycarbonate based resin to which fire-resistance is imparted, is used, and as the innermost layer, a heat-bondable resin layer is used. SOLUTION: A co-extrusion film forming by a feed block T die is performed. The outermost layer is formed as a fire-resistant insulating resin layer (a thickness of 60 μm) wherein 40 pts.wt. of ammonium polyphosphate as a fire-resistant agent, and 5 pts.wt. of silicon dioxide as a fire-resistant assistant are blended based on 100 pts.wt. of polycarbonate. This film for flat cable is obtained by laminating a heat-bondable, resin layer (a thickness of 90 μm) comprising maleate denatured polyolefin on the internal surface of the outermost layer. Thus, the film forming can be performed without a drawing, and the flexibility of them film can be increased. In addition, since a resin which is comparatively stable against a temperature variation is used, the heat resistance and the workability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a covering film for a flat cable used for internal wiring of various communication devices, home appliances, computers, houses and the like.

[0002]

2. Description of the Related Art In a flat cable, a plurality of linear conductors are sandwiched between a pair of films, and the inner surfaces of these films are adhered to each other to cover the conductors. Conventionally, as such a film for a flat cable, a film obtained by laminating a heat-adhesive layer provided with flame retardancy on a non-flame retardant base layer has been generally used. Therefore, in such a film for a flat cable, the inner heat bonding layer has flame retardancy, and the outer surface of the coated cable does not have flame retardancy, which makes the cable insusceptible to external combustion. was there.

JP-A-53-65886 discloses a flat cable film in which a flame-retardant coating film or the like is formed on a polyester base material layer. Since the outermost layer of such a film for a flat cable has flame retardancy, it can cope with external combustion, but a flame retardant coating film is formed on the base material layer. This requires a complicated process, which complicates the manufacturing process.

A polyester resin is used for the base material layer. When a polyethylene terephthalate-based resin is used as the polyester resin, the polyethylene terephthalate-based resin has excellent mechanical properties and electrical properties, but has a high rigidity. And the flexibility is not good. Recently, a film for a flat cable using a polybutylene terephthalate resin having the flame retardancy of a base material layer is known. However, when the base material layer is thermally bonded to a cable in a secondary process, the base material layer is thermally deformed. However, there is a problem that the dimensional stability of the product is not good. Further, polybutylene terephthalate-based resin is inherently hard and brittle, and such a tendency is further increased at a low temperature, so that there is a limit in flexibility and a use temperature range.

[0005] Further, polybutylene terephthalate resin has a problem that a hydrolysis reaction is caused by contact with moisture or moisture, and the reaction is rapidly degraded, resulting in poor water resistance.

In the conventional production of a film for a flat cable, a primer layer is applied to a base material layer, a flame-retardant adhesive is applied by a roll coater or the like, and then dried to form an adhesive layer. The extrusion lamination method of directly extruding a flame-retardant adhesive resin from a mold to form an adhesive layer, and the dry lamination method of adhering a flame-retardant film to a substrate layer have been adopted. In this method, a process of applying a primer to the base material layer, a lead time for curing the adhesive, and the like are required, and there is a problem that the manufacturing process is complicated.

An object of the present invention is to solve these conventional problems, improve the flame retardancy on the outer surface, and provide a film for a flat cable which can be manufactured by a simpler process. .

[0008]

SUMMARY OF THE INVENTION The present invention provides a film for a flat cable for sandwiching a linear conductor between a pair of films and bonding the inner surfaces of the pair of films to cover the conductor to form a flat cable. And characterized in that a flame-retardant insulating resin layer made of polycarbonate resin having flame retardancy is used as the outermost layer, and a heat-adhesive resin layer is used as the innermost layer.

In the present specification, the "outermost layer" is the outermost layer in a state where the cable is covered with the film of the present invention, and the "innermost layer" is the state where the linear conductor is sandwiched. Refers to the innermost layer opposed to the innermost layer.

[0010] In the present invention, the polycarbonate resin having the flame retardancy, which constitutes the flame retardant insulating resin layer used as the outermost layer, can be prepared, for example, by blending a flame retardant with the polycarbonate resin. . Examples of the flame retardant used include halogen-based tetrabromoxylene, phosphorus-based tri-phenylphosphite, inorganic-based antimony trioxide, aluminum oxide, and magnesium oxide. From the viewpoint of improving the flame retardant effect, it is particularly preferable to use a halogen-based flame retardant and antimony trioxide in combination. The compounding amount of the flame retardant is preferably 5 to 200 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the polycarbonate resin. If the compounding amount of the flame retardant is less than 5 parts by weight, the flame retarding effect becomes insufficient, and if it exceeds 200 parts by weight, although the flame retardancy is very good, the dispersibility of the flame retardant becomes poor and the film is formed. May be difficult.

In the present invention, the thickness of the flame-retardant insulating resin layer is preferably 25 to 500 μm, more preferably 50 to 500 μm.
１００100 μm. If the thickness of the flame-retardant insulating resin layer is too thin, the flame-retardant effect may be insufficient or deformation due to weakness of the waist may occur. Also, if the thickness is too thick,
There is a possibility that the waist is too strong and lacks flexibility.

The heat-adhesive resin layer used as the innermost layer in the present invention may be any layer that can be heat-adhered to the covering linear conductor, that is, the cable. For example, maleic acid-modified polyolefin, ethylene-acrylic An acid copolymer or the like can be used.

The thickness of the heat-adhesive resin layer may be a thickness that can cover the cable, and is 50 to 500 μm.
m is preferable, and more preferably 60 to 100 μm. For example, when covering a cable having a diameter of 120 μm, which is a general type, the thickness of the heat-adhesive resin layer is 6 μm.
It is preferably about 5 to 90 μm.

Preferably, a metal deactivator is added to the heat-adhesive resin layer to prevent the heat-adhesive resin from deteriorating. Further, by using an antioxidant together with a metal deactivator, deterioration can be more effectively prevented.

Examples of the metal deactivator include hydrazines such as N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and benzotriazoles.

Examples of the antioxidant include hindered phenols such as pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propineato].

The film of the present invention may be a laminated film having at least two layers having a flame-retardant insulating resin layer as an outermost layer and a heat-adhesive resin layer as an innermost layer. Another layer may be formed between them.

The method for producing the flat cable film of the present invention is not particularly limited, and it can be produced by the above-mentioned conventional coating method, extrusion laminating method, dry laminating method or the like. The cable film can also be manufactured by a co-extrusion method. Therefore, a step of applying a primer and a lead time for curing an adhesive as in the related art are not required, and the production can be simplified.

As the coextrusion method, for example, any of the inflation method and the T-die method can be applied. Also,
It is also possible to extrude a three-layer film having an adhesive resin layer between the flame-retardant insulating resin layer and the heat-adhesive resin layer at a time. Further, according to the T-die method, since the surface can be roughened, it is possible to easily prevent blocking of the heat-adhesive resin layer.

The action in the flat cable film of the present invention, the outermost layer,
A flame-retardant insulating resin layer made of a polycarbonate resin having flame retardancy is provided. The polycarbonate-based resin inherently has flame retardancy, and the present invention further imparts flame retardancy. Therefore, an insulating resin layer having excellent flame retardancy is provided as the outermost layer. Therefore, it is possible to sufficiently cope with combustion from the outer layer surface side.

Further, since the polycarbonate resin is used, there is little change in toughness even at ordinary temperature and low temperature.
The operating temperature range can be widened. Therefore, it can also be used for applications with large temperature changes.

Further, the polycarbonate resin has a low molding shrinkage, is excellent in dimensional stability, and has a glass transition temperature (Tg) of about 140 ° C., so that it can be used even in the secondary processing for heat bonding with a cable. It is not adversely affected by the heat of processing.

Further, the polycarbonate resin has an advantage that it is hardly affected by moisture or moisture since it has a low water content and excellent water resistance. Further, as described above, since the film for a flat cable of the present invention can be manufactured by a co-extrusion film forming method, the number of steps required for the production can be reduced and the production can be performed at low cost. .

Further, since the flame-retardant insulating resin layer used in the present invention can be formed in a non-stretched state, the flexibility can be improved as compared with a conventional film using polyethylene terephthalate as a base layer. Further, since the density is relatively low, the weight can be reduced as compared with the conventional film.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to specific examples. (Example 1) By co-extrusion film formation using a feed block T-die, the outermost layer was made up of 100 parts by weight of polycarbonate (hereinafter abbreviated as PC), 40 parts by weight of ammonium polyphosphate as a flame retardant, and carbon dioxide as a flame retardant auxiliary. 5 silicon
Flame-retardant insulating resin layer mixed with parts by weight (60 μm thick)
And a film for a flat cable in which a heat-adhesive resin layer (thickness: 90 μm) made of maleic acid-modified polyolefin was laminated on the inner surface thereof.

Example 2 By co-extrusion film formation using a feed block T die, the outermost layer was 100 parts by weight of PC, 5 parts by weight of ammonium polyphosphate as a flame retardant,
A flame-retardant insulating resin layer (thickness: 60 μm) containing 5 parts by weight of silicon dioxide as a flame-retardant aid, and a heat-adhesive resin layer (thickness: 90 μm) made of maleic acid-modified polyolefin on the inner surface of these layers Were laminated to obtain a film for a flat cable.

Example 3 By coextrusion film formation using a feed block T-die, the outermost layer was 80 parts by weight of ammonium polyphosphate as a flame retardant and 10 parts by weight of silicon dioxide as a flame retardant, based on 100 parts by weight of PC. A flame retardant insulating resin layer (thickness: 60 μm) was blended to form a flat cable film in which a thermoadhesive resin layer (thickness: 90 μm) made of maleic acid-modified polyolefin was laminated on the inner surface.

(Comparative Example 1) By coextrusion film formation using a feed block T die, the outermost layer was made of polybutylene terephthalate (hereinafter abbreviated as PBT) 100 parts by weight, and ammonium polyphosphate 40 parts by weight as a flame retardant. A flame-retardant insulating resin layer (thickness: 60 μm) containing 5 parts by weight of silicon dioxide as a combustion aid is formed, and a heat-adhesive resin layer (male: 90 μm) made of maleic acid-modified polyolefin is formed on the inner surface of these layers. A laminated flat cable film was obtained.

(Comparative Example 2) By co-extrusion film formation using a feed block T die, the outermost layer was 5 parts by weight of ammonium polyphosphate as a flame retardant and 5 parts by weight of silicon dioxide as a flame retardant, based on 100 parts by weight of PBT. A flame retardant insulating resin layer (thickness: 60 μm) was blended to form a flat cable film in which a thermoadhesive resin layer (thickness: 90 μm) made of maleic acid-modified polyolefin was laminated on the inner surface.

(Comparative Example 3) A urethane-based primer was applied to biaxially stretched polyethylene terephthalate having a thickness of 50 μm, and then a flame-retardant heat-adhesive resin having a thickness of 80 μm (a terpolymer of ethylene, glycidyl methacrylate and vinyl acetate was used). After dry laminating (halogen-based flame retardant and antimony trioxide are added), lead time is 3 days and total thickness is 1
A 30 μm film for a flat cable was obtained.

Table 1 summarizes the layer structure, the amount (parts by weight) of the flame retardant, and the manufacturing method of the flat cable films of Examples 1 to 3 and Comparative Examples 1 to 3 obtained as described above.

[0032]

[Table 1]

With respect to the samples of Examples and Comparative Examples obtained as described above, the molding shrinkage, flame retardancy, water resistance,
The bending strength and the flexibility (flexural modulus) were evaluated. The evaluation method is as follows.

(1) Flame retardancy JIS C 3005-28 (A sample having a length of about 300 mm is held horizontally, and an oxidizing flame of an alcohol lamp having a length of about 5
0mm or Bunsen burner oxidation flame length about 130
After applying the tip of a reducing flame of mm to the center of the sample until it burns from the lower side within 30 seconds, the flame is gently removed, and the time until it disappears naturally is measured. ) Was evaluated for samples in which the adhesive layers were laminated. (Practically 30 after ignition
A level that extinguishes spontaneously within seconds is required. )

(2) Flexibility (Flexural Modulus) Measured in accordance with JIS K 7171-1994 “Flexural Modulus”. (3) Water resistance Measured in accordance with JIS K 7209-1984 "Test Method for Water Absorption of Plastics and Water Absorption of Boiling Water".

(4) Molding Shrinkage Measured in accordance with JIS K 6911-1979 "General Test Method for Thermosetting Plastics".

(5) Bending strength Measured according to JIS K 7116-1987 "Bending strength". Table 2 shows the evaluation results.

[0038]

[Table 2]

As is clear from Table 2, the film for a flat cable according to the present invention is excellent in flame retardancy and has good flexibility.

[0040]

In the flat cable film of the present invention, the outermost layer is provided with a flame-retardant insulating resin layer made of polycarbonate resin having flame retardancy. For this reason, the flame resistance of the covered cable against external combustion can be significantly improved.

Further, since the polycarbonate resin is used, the film can be formed without stretching, and the flexibility of the film can be enhanced. Further, since a polycarbonate resin that is relatively stable against temperature changes is used, heat resistance and workability can be improved. Further, since the resin has a relatively low density, the weight can be reduced.

The film for a flat cable of the present invention comprises:
Since a film can be formed by a co-extrusion method, the number of steps required for production can be reduced, and production can be performed with high production efficiency.

Claims (1)

[Claims] 1. A flat cable film for sandwiching a linear conductor between a pair of films and bonding the inner surfaces thereof to cover the conductor to form a flat cable. A film for a flat cable, characterized by using a flame-retardant insulating resin layer made of a polycarbonate-based resin provided with a resin, and using a heat-adhesive resin layer as an innermost layer.