KR20170141817A - Multilayer resin sheet for high-speed transmission flexible flat cable, and high-speed transmission flexible cable - Google Patents

Abstract

It is an object of the present invention to provide a multilayer resin sheet for a high-speed transfer flexible flat cable capable of forming a high-speed transfer flexible flat cable having a desired characteristic impedance and less dielectric loss. A multilayer resin sheet for a high-speed transfer flexible flat cable laminated between a conductor layer disposed in a predetermined pattern and a shield layer laminated on at least one outer surface side of the conductor layer, the multilayer resin sheet comprising: a base film; Layered resin sheet for a high-speed transfer flexible flat cable, which has a flame-retardant layer laminated on the side of the flame-retardant layer and a conductor base layer laminated on the inner surface side of the flame-retardant layer and containing no flame retardant. The average thickness of the flame-retardant layer is preferably 10 탆 or more and 300 탆 or less. The average thickness of the flame-retardant layer is preferably 25% or more and 90% or less of the total average thickness.

Description

[0001] MULTILAYER RESIN SHEET FOR HIGH-SPEED TRANSMISSION FLEXIBLE FLAT CABLE, AND HIGH-SPEED TRANSMISSION FLEXIBLE CABLE [0002]

The present invention relates to a multilayer resin sheet for a high-speed transmission flexible flat cable and a high-speed transmission flexible flat cable.

A flexible flat cable of a multi-core flat type is used as a wire for internal wiring of electronic equipment. This flexible flat cable is manufactured by sandwiching a plurality of strip-shaped conductors in parallel between two sheets of insulating resin sheets and integrating them in a pressurizing and heating process such as a thermal lamination process.

Particularly, in a digital device or the like, a flexible flat cable is used to transmit a digital signal. When a digital signal is transmitted, it is preferable to block the electromagnetic noise from the outside. Therefore, a flexible flat cable in which a conductive shield layer is laminated on the outer surface of a resin sheet is often used. Further, in order to accurately transmit the high-frequency signal, it is necessary to match the characteristic impedance between the circuit and the flexible flat cable.

To this end, it has been proposed to increase the characteristic impedance between the conductor and the shield layer by interposing a low dielectric constant layer mainly composed of polyolefin between the shielding layer and the insulating resin sheet containing polyester as its main component Japanese Patent Application Laid-Open No. 2008-047505).

A resin sheet (insulating tape) for a flexible flat cable that increases the characteristic impedance by laminating an adhesive layer made of a foamed resin to be bonded to a conductor to an insulating resin film has also been proposed (Japanese Patent Application Laid- 251261).

Japanese Patent Application Laid-Open No. 2008-047505 Japanese Patent Application Laid-Open No. 2008-251261

Since the flexible flat cable is required to have flame retardancy, the resin sheet for a flat cable needs to contain a flame retardant. Therefore, in the structure of the conventional resin sheet for a flexible flat cable as disclosed in Japanese Patent Laid-Open Publication No. 2008-047505, since the resin disposed around the conductor contains the flame retardant, the dielectric constant can not be sufficiently lowered, Transmitting a signal can generate genetic hand.

Further, in the structure of Japanese Patent Application Laid-Open No. 2008-251261, the dielectric constant of the resin in the vicinity of the conductor is changed by bending the resin in the vicinity of the conductor by the thermal compression during the formation of the flat cable or the bending during use of the flat cable , It is not easy to adjust the characteristic impedance of the flat cable.

The present invention has been made based on the above-described circumstances, and it is an object of the present invention to provide a multilayer resin sheet for a high-speed transfer flexible flat cable and a high-speed transfer flexible flat cable capable of forming a high-speed transfer flexible flat cable having a desired characteristic impedance, And the like.

The present invention made to solve the above problems is a multilayer resin sheet for a high-speed transfer flexible flat cable laminated between a conductor layer disposed (arranged) in a predetermined pattern and a shield layer laminated on at least one outer surface side of the conductor layer A base film; a flame retardant layer laminated on the inner surface side of the base film, the flame retardant layer containing a flame retardant; and a conductor surrounding layer laminated on the inner surface side of the flame retardant layer and containing no flame retardant.

The multilayer resin sheet for a high-speed transmission flexible flat cable of the present invention can form a high-speed transmission flexible flat cable having a desired characteristic impedance because the permittivity and dielectric tangent of the conductor base layer around the conductor layer is low and constant, It is possible to reduce the dielectric hand of the flexible flat cable.

1 is a schematic cross-sectional view showing a multilayer resin sheet for a high-speed flexible flat cable according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a high-speed transmission flexible flat cable including a multilayer resin sheet for a high-speed transmission flexible flat cable of FIG.
3 is a schematic cross-sectional view of a high-speed transmission flexible flat cable of a different embodiment from that of Fig.

[Description of Embodiments of the Present Invention]

A multilayer resin sheet for a high-speed transfer flexible flat cable laminated between a conductor layer disposed in a predetermined pattern and a shield layer laminated on at least one outer surface side of the conductor layer, the multilayer resin sheet comprising: a base film; Layered resin sheet for a high-speed transfer flexible flat cable, which has a flame-retardant layer laminated on the side of the flame-retardant layer and a conductor base layer laminated on the inner surface side of the flame-retardant layer and containing no flame retardant.

The multilayer resin sheet for the high-speed transmission flexible flat cable is laminated on the outer surface side of the conductor layer to form a high-speed flexible flat cable. Since the conductor ground layer adjacent to the conductor layer does not contain any flame retardant, The characteristic impedance of the formed high-speed transmission flexible flat cable can be easily adjusted to a desired value. Further, in the multilayer resin sheet for a high-speed transmission flexible flat cable, since the conductive base layer does not contain a flame retardant as described above, the dielectric constant and dielectric tangent of this layer are small. As a result, since the distance between the conductor layer and the shield layer can be reduced, the high-speed transmission flexible flat cable can be thinned, and even when the conductor layer transmits a high-frequency signal in the formed high- Do not.

The average thickness of the flame-retardant layer is preferably 10 탆 or more and 300 탆 or less. By setting the average thickness of the flame-retardant layer within the above range, sufficient flame retardancy and sufficient flexibility can be ensured.

The average thickness of the flame-retardant layer is preferably 25% or more and 90% or less of the total average thickness.

By setting the average thickness of the flame-retardant layer within the above-mentioned range, sufficient flame retardancy can be ensured and a sufficient thickness of the base film and the conductor base layer can be ensured.

The main resin component of the base film may be polyethylene terephthalate or polyphenylene sulfide, and the main resin component of the flame retardant layer may be polypropylene. By using the above material as the main component of the resin of the base film and the flame-retardant layer as described above, good workability and economy can be obtained.

An adhesive layer may be further provided between the base film and the flame retardant layer. By providing the adhesive layer in this way, the adhesion between the base film and the flame retardant layer is improved, and reliability can be improved.

It is preferable that the adhesive layer does not contain a flame retardant. In this manner, the characteristic impedance between the conductor layer and the shield layer can be made smaller by not adding the flame retardant to the adhesive layer, and the adhesion between the base film and the flame retardant layer can be further improved. Further, when the adhesive layer is extrusion-molded, the flame retardant gas is not added to the opening portion of the die, so that the productivity can be improved.

The main resin component of the adhesive layer may be an acid-modified polypropylene. By thus forming the main resin component of the adhesive layer with acid-modified polypropylene, the adhesion between the base film and the flame retardant layer can be further improved.

The present invention also provides a high-speed transfer flexible flat plate having a conductor layer arranged in a predetermined pattern, a shield layer laminated on at least one outer surface side of the conductor layer, and an insulating layer laminated between the conductor layer and the shield layer, Wherein the insulating layer is a multilayer resin sheet for the high-speed transmission flexible flat cable and includes a high-speed transmission flexible flat cable in which the conductor ground layer and the conductor layer are in contact with each other.

In the high-speed transmission flexible flat cable, since the multilayer resin sheet for the high-speed transmission flexible flat cable has a constant and small dielectric constant, the error of characteristic impedance is small and the dielectric loss at the time of high frequency signal transmission is small.

The average thickness of the conductive base layer between the predetermined patterns of the conductor layers is preferably 50% or more of the average thickness of the conductor layers. By setting the average thickness of the conductive base layer to be equal to or more than the lower limit described above, the conductive base layer is filled between the conductors of the conductive layer, so that the dielectric loss can be further reduced.

The flame-retardant layer of the multilayer resin sheet for the high-speed transmission flexible flat cable may not be filled between predetermined patterns of the conductor layer. Thereby, it is possible to more effectively prevent the dielectric loss near the conductor layer from being reduced and the dielectric loss to be increased.

Here, the term " outer side " and " inner side " refer to a side closer to the conductor layer in the high-speed transmission flexible flat cable, and " The " main resin component " refers to a resin component having the highest mass content among the resin components, and preferably refers to a resin component containing 50 mass% or more. The phrase " the flame-retardant layer is filled between predetermined patterns of the conductor layer " means a state in which the flame-retardant layer is present in the space between the pattern conductors of the conductor layer. The " average thickness of the conductive base layer between predetermined patterns of the conductor layer " refers to the average thickness of the conductor base layer between the pattern conductors of the conductive layer.

[Detailed Description of Embodiments of the Present Invention]

Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.

[Multilayer resin sheet for high-speed transmission flexible flat cable]

The multilayer resin sheet 1 for a high-speed flexible flat cable of Fig. 1 comprises a base film 2, an adhesive layer 3 laminated on the inner surface of the base film 2, and an adhesive layer 3 laminated on the inner surface of the adhesive layer 3 , A flame retardant layer (4) containing a flame retardant, and a conductor base layer (5) laminated on the inner surface of the flame retardant layer (4) and containing no flame retardant.

<Base film>

As the base film 2, a film mainly composed of an insulating resin is used. As the insulating resin of the base film 2, for example, polyester, polyphenylene sulfide, polyimide and the like can be mentioned. Of these, polyesters or polyphenylene sulfides having general versatility are preferable. Here, the main component means a component having the largest mass content, and preferably refers to a component having a mass content of 50 mass% or more.

Examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, polystyrene terephthalate, polystyrene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate and polycyclohexane dimethyl terephthalate . Of the polyesters, polyethylene terephthalate is preferable from the standpoints of electrical characteristics, mechanical properties, cost, and the like.

The base film 2 may be one having an inner surface subjected to a surface treatment in order to improve the adhesiveness. The surface treatment may be corona treatment, for example. By performing such corona treatment, a polar functional group such as a hydroxyl group or a carbonyl group is introduced to the inner surface side of the base film 2 to impart hydrophilicity. Corona treatment is effective when polyphenylene sulfide is used as an insulating resin. The surface treatment may be carried out by other methods such as chemical treatment. Of course, the surface treatment such as the corona treatment is not limited to the case of using polyphenylene sulfide as an insulating resin, and may be arbitrarily performed even when another insulating resin is used. Further, in order to improve the adhesiveness, a known anchor coating agent may be applied to the inner surface side of the base film 2.

The length dimension and the width dimension of the base film 2 may be appropriately set in accordance with the use or the like. The lower limit of the average thickness of the base film 2 is preferably 6 占 퐉, more preferably 9 占 퐉, and further preferably 12 占 퐉. On the other hand, the upper limit of the average thickness of the base film 2 is preferably 75 占 퐉, more preferably 50 占 퐉, and further preferably 40 占 퐉. If the average thickness is less than the lower limit, sufficient rigidity may not be ensured. If the average thickness exceeds the upper limit, sufficient flexibility may not be ensured.

<Adhesive Layer>

The adhesive layer 3 comprises a resin component. Examples of the main resin component of the adhesive layer 3 include polyolefins. Examples of the polyolefin include a homopolymer of each olefin such as ethylene, propylene, butene, and hexene, a copolymer of these monomers, and a copolymer of these monomers and non-olefin monomers. Specific examples of the polyolefin include ethylene based resins such as low density polyethylene, linear polyethylene (ethylene -? - olefin copolymer) and high density polyethylene, propylene resins such as polypropylene and ethylene-propylene copolymer, ), Poly (butene-1), an ethylene-vinyl acetate copolymer, and an acid-modified polyolefin-based resin obtained by modifying maleic anhydride with these resins (treated). Particularly, as the main resin component of the adhesive layer 3, an acid-modified polyolefin is preferable in order to improve the adhesive force between the base film 2 and the flame-retardant layer 4, more preferably an acid-modified polypropylene. On the other hand, the entire resin component may be composed of only the main resin component.

The lower limit of the average thickness of the adhesive layer 3 is preferably 1 m, more preferably 2 m. On the other hand, the upper limit of the average thickness of the adhesive layer 3 is preferably 50 占 퐉, more preferably 30 占 퐉.

If the average thickness of the adhesive layer 3 is less than the lower limit described above, it is not easy to form a uniform layer and the effect of bonding the base film 2 and the flame retardant layer 4 may not be sufficiently exhibited. If the average thickness of the adhesive layer 3 exceeds the upper limit, the multilayer resin sheet 1 for a high-speed flexible flat cable may be unnecessarily thickened.

The adhesive layer 3 may contain other additives as required, but preferably does not contain a flame retardant. Since the adhesive layer 3 does not contain a flame retardant, the dielectric constant in the vicinity of the surface of the multilayer resin sheet 1 for the high-speed flexible flat cable is reduced, and the multilayer resin sheet 1 for high- The characteristic impedance of the conductor layer and the shield layer can be reduced when the high-speed transmission flexible flat cable is formed. When the adhesive layer 3 is formed by co-extrusion with the flame retardant layer 4 and the conductor base layer 5, the flame retardant is not exposed on the surface of the film, and adhesion to the base film 2 is enhanced. Further, since the flame retardant gas is not added to the opening portion of the die at the time of extrusion molding, the productivity can be improved.

<Flame Retardant Layer>

The flame retarding layer 4 includes a resin component and a flame retardant.

(Resin component)

As the resin component of the flame-retardant layer 4, for example, polyolefin can be mentioned. Examples of the polyolefin include a homopolymer of each olefin such as ethylene, propylene, butene, and hexene, a copolymer of these monomers, and a copolymer of these monomers and non-olefin monomers. Specific examples of the polyolefin include ethylene based resins such as low density polyethylene, linear polyethylene (ethylene -? - olefin copolymer) and high density polyethylene, propylene resins such as polypropylene and ethylene-propylene copolymer, ), Poly (butene-1), an ethylene-vinyl acetate copolymer, and an acid-modified polyolefin-based resin obtained by modifying maleic anhydride with these resins (treated). Particularly, it is preferable to use polypropylene as the main resin component of the flame-retardant layer 4 in view of heat resistance, low dielectric constant, and cost.

(Flame retardant)

Examples of the flame retardant contained in the flame retarding layer 4 include a metal hydrate flame retardant, a halogen flame retardant, and an antimony flame retardant, and these may be used alone or in combination of two or more.

Examples of the metal hydrate-based flame retardant include magnesium hydroxide [Mg (OH) ₂ ], aluminum hydroxide [Al (OH) ₃ ], hydrotalcite, etc. These are used alone or in combination of two or more.

Examples of the halogen-based flame retardant include chlorinated compounds such as chlorinated paraffin, chlorinated polyethylene, chlorinated polyphenyl, perchloropentacyclodecane, anhydrous hic acid and chlorinated acid, tetrabromoethane, tetrabromobisphenol A, hexabromo Bromine compounds such as benzene, decabromobiphenyl ether, tetrabromophthalic anhydride, polydibromophenylene oxide, hexabromocyclododecane, and ammonium bromide; and organic or inorganic compounds containing halogen elements They are used alone or in combination of two or more.

Examples of the antimony-based flame retardant include antimony trioxide, antimony trichloride, antimony pentoxide, antimony borate and antimony molybdate. These antimony flame retardants may be used alone or in combination of two or more.

The lower limit of the content of the flame retardant is preferably 20 parts by mass, more preferably 40 parts by mass, per 100 parts by mass of the resin component of the flame-retardant layer (4). On the other hand, the upper limit of the content of the flame retardant is preferably 200 parts by mass, more preferably 150 parts by mass, per 100 parts by mass of the resin component of the flame-retardant layer (4). If the content of the flame retardant is less than the above lower limit, there is a possibility that sufficient flame retardancy can not be imparted. If the content of the flame retardant exceeds the upper limit, the strength of the flame retardant layer 4 may be insufficient, and the cost may be excessively high.

The flame-retardant layer 4 may contain a flame-retardant additive in order to enhance the effect of the flame-retardant agent. Examples of the flame retarding auxiliary include antimony oxide and the like.

The lower limit of the average thickness of the flame-retardant layer 4 is preferably 10 占 퐉, more preferably 20 占 퐉.

On the other hand, the upper limit of the average thickness of the flame-retardant layer 4 is preferably 300 占 퐉, more preferably 200 占 퐉. If the average thickness of the flame retardant layer 4 is less than the above lower limit, there is a possibility that sufficient flame retardancy can not be imparted to the multilayer resin sheet 1 for the high-speed flexible flat cable. If the average thickness of the flame retardant layer 4 exceeds the upper limit, flexibility of the multilayer resin sheet 1 for the high-speed flexible flat cable may be insufficient.

The lower limit of the ratio of the average thickness of the flame retardant layer 4 to the average thickness of the multilayer resin sheet 1 for a high-speed flexible flat cable is preferably 25%, more preferably 40%. On the other hand, the upper limit of the ratio of the average thickness of the flame-retardant layer 4 is preferably 90%, more preferably 80%. If the ratio of the average thickness of the flame retardant layer 4 is less than the lower limit described above, there is a possibility that sufficient flame retardancy can not be imparted to the multilayer resin sheet 1 for the high-speed flexible flat cable. If the ratio of the average thickness of the flame retardant layer 4 exceeds the upper limit, the dielectric constant in the vicinity of the conductor in the high-speed transmission flexible flat cable becomes high, and the dielectric loss tends to increase.

<Conductor base layer>

The conductive base layer 5 contains resin as a main component and substantially no flame retardant. As the resin to be the main resin component of the conductor ground layer 5, for example, polyolefin can be mentioned. Examples of the polyolefin include a homopolymer of each olefin such as ethylene, propylene, butene, and hexene, a copolymer of these monomers, and a copolymer of these monomers and non-olefin monomers. Specific examples of the polyolefin include ethylene based resins such as low density polyethylene, linear polyethylene (ethylene -? - olefin copolymer) and high density polyethylene, propylene resins such as polypropylene and ethylene-propylene copolymer, ), Poly (butene-1), an ethylene-vinyl acetate copolymer, and acid-modified polyolefin-based resins obtained by modifying (treating) maleic anhydride with these resins, epoxy-modified polyolefins, and silane-modified polyolefins. Particularly, as the main component of the conductive base layer 5, acid-modified polyolefins or epoxy-modified polyolefins are preferable from the viewpoints of adhesiveness to a conductor, lowering of the dielectric constant and cost. Among them, acid-modified polypropylene and epoxy- More preferable.

The lower limit of the average thickness of the conductive base layer 5 is preferably 1 占 퐉, more preferably 3 占 퐉.

On the other hand, the upper limit of the average thickness of the conductive base layer 5 is preferably 100 占 퐉, more preferably 50 占 퐉. If the average thickness of the conductor ground layer 5 is less than the lower limit described above, the proximity of the flame retardant to the conductor layer may increase dielectric loss in the high-speed flexible flat cable. If the average thickness of the conductor ground layer 5 exceeds the upper limit, the flexibility of the multilayer resin sheet 1 for the high-speed transmission flexible flat cable may be insufficient.

<Manufacturing Method>

The method for producing the multilayer resin sheet 1 for a high-speed transfer flexible flat cable includes the steps of adjusting a resin composition for forming the adhesive layer 3, the flame retardant layer 4 and the conductor base layer 5, A step of forming a film constituting the adhesive layer 3, the flame-retardant layer 4 and the conductive base layer 5 by the composition and the step of forming the adhesive layer 3, the flame-retardant layer 4 and the conductive base layer 5 And a step of laminating the film on the base film (2) and integrating the film by thermocompression bonding.

(Resin composition adjusting step)

The resin composition for forming the adhesive layer 3, the flame retardant layer 4 and the conductor base layer 5 can be prepared by kneading a composition containing other components such as a resin component and a flame retardant by a kneader.

Examples of the kneader include an open roll, a kneader, and a twin screw extruder.

(Film Forming Process)

The adhesive layer 3, the flame retardant layer 4 and the conductor base layer 5 can be formed by a melt extrusion method such as a T-die method or an inflation method. The adhesive layer 3, the flame retardant layer 4 and the conductor base layer 5 may be separately formed as independent films or may be formed as an integral three-layer film by coextrusion.

(Thermocompression process)

The multilayer resin sheet 1 for the high-speed transfer flexible flat cable can be formed by laminating the three films or the three-layer films thus formed on the base film 2 and integrating them by thermocompression bonding . The thermocompression bonding can be performed using, for example, a heating laminator equipped with a heating roller, a heating press machine or the like. The heating temperature is, for example, about 80 to 200 占 폚.

[High Speed Transfer Flexible Flat Cable]

The high-speed transmission flexible flat cable shown in Fig. 2 has a conductor layer 6 arranged in a stripe pattern and an insulating layer 7 and a conductor layer 6 laminated on the surface of the conductor layer 6, And a shield layer (9) laminated on the outer surface of the insulating layer (7) on the table side.

The average thickness of the high-speed transmission flexible flat cable may be, for example, 200 占 퐉 or more and 900 占 퐉 or less.

<Conductor Layer>

The conductor layer 6 is formed in a layer shape and has a stripe pattern in which a plurality of band-shaped pattern conductors 6a are arranged in parallel with each other. The conductor layer 6 is made of a conductive metal such as copper, tin-plated interlocking, or nickel-plated interlocking. The conductor layer 6 is preferably formed of a thin conductive metal.

The lower limit of the average thickness of the conductor layer 6 is preferably 10 占 퐉, more preferably 20 占 퐉.

On the other hand, the upper limit of the average thickness of the conductor layer 6 is preferably 100 占 퐉, more preferably 50 占 퐉. If the average thickness of the conductor layer 6 is less than the lower limit described above, the mechanical strength of the conductor layer 6 may be insufficient and the conductor layer 6 may be broken. If the average thickness of the conductor layer 6 exceeds the upper limit, the high-speed transmission flexible flat cable may be unnecessarily thickened, but the flexibility may be insufficient.

The average thickness of the conductive base layer 5 between the pattern conductors 6a of the conductor layer 6 of the multilayer resin sheet 1 for a high-speed transmission flexible flat cable is preferably 50 Or more, more preferably 70% or more. If the average thickness of the conductive base layer 5 is less than the lower limit described above, the conductive base layer 5 alone can not fill between the pattern conductors 6a of the conductor layer 6, The dielectric constant between the pattern conductors 6a is increased because the flame retarding layer 4 is pierced and the loss at the time of transmitting the high frequency signal of the pattern conductor 6a may increase.

&Lt; Insulating layer &

The insulating layers 7 and 8 are each formed by the multilayer resin sheet 1 for high-speed transfer flexible flat cable shown in Fig. These two multilayer resin sheets 1 for high-speed transmission flexible flat cables are laminated on both sides of the conductor layer 6 so that the conductor base layer 5 abuts against the conductor layer 6 and thermally bonded. By this thermocompression bonding, the conductor basis layer 5 of the multilayer resin sheet 1 for two high-speed transmission flexible flat cables is filled between the pattern conductors 6a and welded to each other to be integrated. As described above, the multilayer resin sheets 1 for the two high-speed flexible flat cables constituting the insulating layers 7 and 8 may be the same, or the materials and thicknesses of the respective layers may be different from each other.

<Shield Layer>

The shield layer 9 is for reducing electromagnetic interference and noise, and may be a layer formed of a conductive material. Such a shield layer 9 can be formed, for example, by adhering commercially available shield tape.

As the shielding tape for forming the shielding layer 9, a conductive metal such as silver is deposited on the inner surface of an insulating resin film 10 of, for example, polyethylene terephthalate resin having a thickness of 9 탆 to form a metal deposition layer 11 And a conductive adhesive agent such as silver paste is applied to the inner surface of the metal vapor deposition layer 11 with a thickness of 20 m to form the conductive adhesive agent layer 12. Alternatively, the shield layer 9 may be formed by applying a conductive paint or by adhering a metal foil.

<Manufacturing Method>

The manufacturing method of the high-speed transfer flexible flat cable includes a step of bonding the multilayer resin sheet 1 for high-speed transfer flexible flat cable to both surfaces of the conductor layer 6 to form insulating layers 7 and 8, And a step of forming a shield layer (9) by bonding a shield tape to the outer surface of the insulating layer (7).

(Insulating layer forming step)

In the insulating layer forming step, the multilayer resin sheet 1 for the high-speed transfer flexible flat cable is laminated on the front surface and the back surface of the conductor layer 6, respectively, and the laminate is thermally bonded. The multilayer resin sheet 1 for the high-speed transmission flexible flat cable has a structure in which the conductor base layer 5 is laminated so as to be in contact with the conductor layer 6 and is thermally bonded to the pattern conductor 6a of the conductor layer 6 The conductive base layer 5 of the multilayer resin sheet 1 for the high-speed transfer flexible flat cable on the front and back sides is welded to each other. Thereby, the insulating layer 7 on the front side and the insulating layer 8 on the back side are integrated with the conductor layer 6. The thermocompression bonding can be performed using, for example, a heating laminator equipped with a heating roller, a heating press machine or the like. The heating temperature is, for example, about 80 占 폚 to 200 占 폚.

(Shield layer forming step)

In the shield layer forming step, the shield layer 9 is formed by adhering a shield tape to the outer surface of the insulating layer 7 on the front surface side.

[advantage]

When the high-speed transfer flexible flat cable is formed by using the multilayer resin sheet 1 for the high-speed transfer flexible flat cable, the flame-retardant layer 4 and the conductor basis layer 5 are laminated on the multilayer resin sheet for high- The insulating layer 7 having a small dielectric constant can be formed between the shield layer 9 laminated on the outer surface side of the substrate 1 and the conductor layer 6 laminated on the inner side. Therefore, the characteristic impedance of the high-speed transmission flexible flat cable can be set to a desired value without stacking other films or the like.

Further, in the high-speed transmission flexible flat cable using the multilayer resin sheet 1 for the high-speed transmission flexible flat cable, since the conductor ground layer 5 having a particularly small dielectric constant is disposed around the conductor layer 6, When the genetic hand is small.

[Other Embodiments of High Speed Transfer Flexible Flat Cable]

The high-speed transmission flexible flat cable of Fig. 3 comprises a conductor layer 6, insulating layers 7a and 8a laminated on the front and back surfaces of the conductor layer 6, And a shield layer (9). 3, the conductor layer 6 and the shield layer 9 are the same as the conductor layer 6 and the shield layer 9 of the high-speed transfer flexible flat cable of Fig. 2, And the description thereof will be omitted.

The insulating layers 7a and 8a are formed by a multilayer resin sheet 1a for a high-speed transmission flexible flat cable.

The multilayer resin sheet 1a for a high-speed transmission flexible flat cable has a base film 2, an adhesive layer 3 laminated on the inner surface of the base film 2, And a conductive base layer 5a laminated on the inner surface of the flame-retardant layer 4a and containing no flame retardant.

The structure of the base film 2 and the adhesive layer 3 of the multilayer resin sheet 1a for the high-speed transmission flexible flat cable is the same as that of the base film 2 of the multilayer resin sheet 1 for high- Since they are the same as those of the adhesive layer 3, they are denoted by the same reference numerals and the description thereof is omitted. The flame-retardant layer 4a and the conductor surrounding layer 5a of the multi-layer resin sheet 1a for a high-speed transmission flexible flat cable are the same as those of the multilayer resin sheet 1 for a high- The flame retardant layer 4 and the conductor base layer 5 are the same.

3, the average thickness of the conductor basis layer 5a in the multilayer resin sheet 1a for a high-speed transmission flexible flat cable before lamination to the conductor layer 6 is larger than the average thickness of the conductor layer 6 Is less than 50% of the average thickness so that the conductive base layer 5a does not fill the entire space between the predetermined patterns of the conductor layer 6. That is, the average thickness of the conductor base layer 5a between the pattern conductors 6a in the high-speed transmission flexible flat cable of Fig. 3 is smaller than 50% of the average thickness of the conductor layer 6. [ Even in the case where the flame retardant is not contained only in the thin layer-shaped portion which directly contacts the pattern conductor 6a and generates dielectric hand, as in the multilayer resin sheet 1 for high-speed transfer flexible flat cable in Fig. 1, Can be reduced.

[Other Embodiments]

It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in all respects. The scope of the present invention is not limited to the configuration of the above-described embodiments, but is defined by the claims, and it is intended that all modifications within the scope and meaning equivalent to the claims of the claims are included.

For example, in the multilayer resin sheet for the high-speed flexible flat cable, the adhesive layer may be omitted.

The high-speed transmission flexible flat cable may have not only a shield layer but also a shield layer on both outer sides.

The multilayer resin sheet for high-speed transfer flexible flat cable can be produced by dissolving the resin composition constituting the adhesive layer, the flame-retardant layer and the conductor base layer in a solvent, sequentially coating the inner surface of the base film and drying .

Example

Hereinafter, the present invention will be described on the basis of examples. It should be noted that the present invention is not limited to these examples, and these examples can be modified or changed based on the object of the present invention, and they are not excluded from the scope of the present invention.

<Multilayer Resin Sheet for High Speed Transfer Flexible Flat Cable>

In order to verify the present invention, the multi-layered resin sheet for high-speed transmission flexible flat cable No. 3 was prepared. 1 to 10 were produced.

First, the multilayer resin sheet No. 3 for high-speed transfer flexible flat cable No. 3 was prepared. In order to form the adhesive layers 1 to 10, the flame-retardant layer and the conductive base layer, the following materials A to F were adjusted.

(Material A)

To 100 parts by mass of the acid-modified polypropylene was added 1 part by mass of an antioxidant.

(Material B)

40 parts by mass of a flame retardant, 10 parts by mass of a flame retardant auxiliary and 1 part by mass of an antioxidant were added to 100 parts by mass of an acid-modified polypropylene.

(Material C)

110 parts by mass of a flame retardant, 30 parts by mass of a flame retarding auxiliary and 1 part by mass of an antioxidant were added to 100 parts by mass of polypropylene.

(Material D)

80 parts by mass of a flame retardant, 10 parts by mass of a flame retardant auxiliary and 1 part by mass of an antioxidant were added to 100 parts by mass of polypropylene.

(Material E)

To 100 parts by mass of polypropylene was added 1 part by mass of an antioxidant.

(Material F)

1 part by mass of an antioxidant was added to 100 parts by mass of a resin composition comprising 90 parts by mass of an epoxy-modified polyolefin and 10 parts by mass of an olefinic elastomer.

As the above-mentioned acid-modified polypropylene, "Admer QE060" manufactured by Mitsui Chemicals, Inc., "WELNEX RFG4 VA" manufactured by Nippon Polypropylene was used as the polypropylene, and "Bond Fast E" manufactured by Sumitomo Chemical Co., DYNARON 6200P "manufactured by JSR Corporation is used as the olefin elastomer," SAYTEX 8010 "is used as the flame retarder, antimony oxide is used as the flame retarding aid, and as the antioxidant, BASF's "Igarox 1076" was used.

The adhesive layer, the flame-retardant layer and the conductive base layer were simultaneously formed by co-extrusion using materials selected from the above materials A to F using a multi-layer T-die to obtain a three-layer film in which these layers were integrated. By applying an anchor coating agent to the base film and bonding the three-layer film, the multilayer resin sheet No. 3 for high-speed transfer flexible flat cable was obtained. 1 to 10 were obtained.

As the base film, a film made of polyethylene terephthalate having an average thickness of 12 占 퐉 was used. As an anchor coating agent, a mixture of Takeka A-310 and Takenate A-3 of Mitsui Chemicals, Inc. was used.

Multilayer resin sheet for high-speed flexible flat cable. The adhesive layers 1 to 10, the flame-retardant layer and the conductor surrounding layer were adjusted to have an average thickness shown in Table 1 using the materials shown in Table 1, respectively.

<High speed transmission flexible flat cable>

As shown in Table 2, the multi-layered resin sheet for high-speed transfer flexible flat cable No. 3 was used. 1 to 10 are used to form an insulating layer, and a high-speed transfer flexible flat cable No. 1 to 10 is formed. 11 to 18 were produced. On the other hand, the high-speed transmission flexible flat cable No. 1. 11 to 18, the target value of the characteristic impedance was set to 100?, And the thickness of each layer and the like were selected.

As the conductor layer, a rolled copper foil having a thickness of 35 mu m and a width of 0.3 mm was used. The multi-layer resin sheet for the high-speed transmission flexible flat cable was placed on the front and back of the metal foil so that the conductive base layer came in contact with the conductor layer and thermally bonded. For the thermocompression bonding, a heat roll having a temperature of 140 캜 to 160 캜 was used. By this thermocompression bonding, the conductive base layer of the multilayer resin sheet for high-speed transfer flexible flat cables on the front and back sides was softened to fill the gaps between the conductors of the conductor layers and bonded to each other.

The high-speed transfer flexible flat cable No. 1 obtained in this way is referred to as &quot; Vertical combustion tests were conducted for 11 to 18. Here, &quot; vertical combustion test &quot; means a vertical combustion test specified by the UL (American Insurer Safety Test Laboratory) standard. The results of this test are shown together in Table 2. This test result indicates that satisfying the criteria of the vertical combustion test specified by VW-1 of UL is good (G), and that which does not satisfy the above criteria is shown as bad (NG).

Next, the high-speed transmission flexible flat cable No. 1 is used. 11 to 15, 17, and 18, the high-speed transfer flexible flat cable No. 1 to the outer surface of the insulating layer on the table side. 16, a shield tape was bonded to the outer surfaces of the insulating layers on both sides of the front and back sides.

As the shield tape, silver was deposited on the inner surface side of a polyethylene terephthalate film having a thickness of 9 占 퐉, and silver paste having a thickness of 20 占 퐉 was coated on the silver deposition surface.

A high-speed transfer flexible flat cable No. 1 having a shield tape adhered thereto as described above. The characteristic impedances between the conductor layers 11 to 18 and the shield layer on the front surface side are measured and the results are shown in Table 2. Herein, the characteristic impedance is a value measured using "Network Analyzer E8362B" manufactured by Agilent Technologies Inc. and "S Parameter Test Set N4419B" manufactured by Agilent Technologies.

As described above, these high-speed transfer flexible flat cables have a multilayer resin sheet for a high-speed transfer flexible flat cable having a low flame retardant layer thickness. 9 Flexible Flat Cable with High Speed Transmission No. Except for 17, it had flammability equivalent to VW-1 of UL standard. On the other hand, since the VW-1 test of the UL standard is carried out in a state in which the shield tape is not adhered, the test result is different from the flame retardancy in the actually used state (state in which the shield tape is adhered).

With respect to the error of the characteristic impedance, All 11 to 18 high-speed flexible flat cables were within 5% of the permissible range.

These no. The high-speed transmission flexible flat cables 11 to 18 all have a conductor ground layer not containing a flame retardant around the conductor layer, so that the dielectric loss at the time of transmitting a high-frequency signal was small. For example, 15 has a loss of about 12 dB at a high frequency signal of 8 GHz and is sufficiently low in loss compared to the loss (17 to 25 dB) of a conventional flexible flat cable.

1, 1a: Multilayer resin sheet for high-speed flexible cable
2: base film
3: Adhesive layer
4, 4a: Flame retardant layer
5, 5a: conductor upper layer
6: conductor layer
6a: pattern conductor
7, 7a, 8, 8a: insulating layer
9: Shield layer (shield tape)
10: Resin film
11: Metal deposition layer
12: Conductive adhesive layer

Claims (9)

A multilayer resin sheet for a high-speed transfer flexible flat cable laminated between a conductor layer disposed in a predetermined pattern and a shield layer laminated on at least one outer surface side of the conductor layer,
A base film,
A flame retardant layer laminated on the inner surface side of the base film,
And a conductor surrounding layer which is laminated on the inner surface side of the flame retardant layer and contains no flame retardant,
And,
The average thickness of the conductive base layer is 25 占 퐉 or more and 50 占 퐉 or less,
Wherein the average thickness of the conductive base layer between the predetermined patterns of the conductive layers is 50% or more of the average thickness of the conductive layers. The method according to claim 1,
Wherein the average thickness of the flame-retardant layer is not less than 10 占 퐉 and not more than 300 占 퐉. 3. The method according to claim 1 or 2,
Wherein the average thickness of the flame-retardant layer is 25% to 90% of the average thickness of the entire multilayer resin sheet. 3. The method according to claim 1 or 2,
Wherein the main resin component of the base film is polyethylene terephthalate or polyphenylene sulfide, and the main resin component of the flame retardant layer is polypropylene. 3. The method according to claim 1 or 2,
Further comprising an adhesive layer laminated between the base film and the flame retardant layer. 6. The method of claim 5,
Layer resin sheet for a high-speed transmission flexible flat cable, wherein the adhesive layer does not contain a flame retardant. 6. The method of claim 5,
Wherein the main resin component of the adhesive layer is an acid-modified polypropylene. A conductor layer disposed in a predetermined pattern,
A shield layer laminated on at least one outer surface side of the conductor layer,
An insulating layer laminated between the conductor layer and the shield layer;
Wherein the flexible flat cable comprises:
The high-speed transfer flexible flat cable in which the insulating layer is a multilayer resin sheet for a high-speed transmission flexible flat cable according to claim 1, wherein the conductor ground layer and the conductor layer are in contact with each other. 9. The method of claim 8,
Wherein the flame retardant layer of the multilayer resin sheet for the high-speed transmission flexible flat cable is not filled between predetermined patterns of the conductor layer.

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