KR20180035715A - Polyimide film having adhesives attached thereto - Google Patents

Abstract

Provided is a polyimide film which is useful for producing flat cables and ensures excellent flame retardance even when having an adhesive layer. To this end, an adhesive is attached to the polyimide film while an oxygen index is set to 30% or more. The polyimide film is attached with an adhesive, and the oxygen index is set to 30% or more. In the adhesive-attached polyimide film, the adhesive layer satisfies a needle insertion rate of 10% or less at 100°C, and/or 20% or more at 140°C, regarding the needle insertion rate for thickness of the adhesive layer in measuring a TMA needle insertion mode.

Description

[0001] The present invention relates to a polyimide film having adhesives attached thereto,

The present invention relates to an adhesive-attached polyimide film useful for producing a flat cable produced by sandwiching a conductor between two substrates having an adhesive layer and an insulator layer, and a flat cable composed of the adhesive-loaded polyimide film.

Flat cables are widely used in electric devices such as televisions, mobile phones, tablets, and hard disks of personal computers. In the flat cable, a conductor such as a copper foil formed in a wiring shape is arranged between a substrate having an insulator layer and an adhesive layer (or simply referred to as " substrate for flat cable " .

Such a flat cable is required to have high flame retardancy, and a technique for improving flame retardancy in a flat cable has been developed.

Patent Literature 1 discloses a flat cable in which a plurality of conductors are placed in parallel with each adhesive layer interposed between two insulating substrates having an insulating film layer and an adhesive layer and thermally fused, Wherein the film layer is formed by an aromatic polymer (polyimide or the like) having an aromatic ring in the molecular skeleton, not containing halogen, and having a limiting oxygen index of 30% or more, A non-halogen flame retardant flat cable comprising a composition containing 50 to 200 parts by weight of a metal hydrate and containing no halide is disclosed.

Patent Document 1: JP-A-5-217430

An object of the present invention is to provide a polyimide film (substrate) with an adhesive excellent in flame retardancy and a flat cable composed of the polyimide film.

Another object of the present invention is to provide an adhesive-attached polyimide film excellent in heat resistance (also, dimensional stability by heat) and a flat cable composed of the polyimide film.

It is still another object of the present invention to provide a polyimide film with an adhesive capable of effectively suppressing or preventing bubble generation and a flat cable composed of the polyimide film.

Among the base films used in flat cables, the present inventors paid attention to polyimide films and studied new methods of smearing the flame retardant in a polyimide film provided with an adhesive layer. However, 1 metal hydrate or the like) is not used, and it is difficult to improve the flame retardancy.

Among them, the inventors of the present invention have conducted intensive and new investigations, and as a result, they have found that a polyimide film and an adhesive layer can be selected from a prescription or a treatment of a polyimide film or a needle insertion amount in a TMA needle insertion mode measurement of an adhesive layer (Or even non-halogen-based) is not used in the adhesive layer even though the adhesive layer is provided by adjusting the thickness ratio of the polyimide film and the adhesive layer, (That is, a high flame retardancy) adhesive-coated polyimide film, and that the adhesive-attached polyimide film is excellent in heat resistance and dimensional stability due to heat.

In addition, when a flat cable is formed by inserting a conductor with a base material for a flat cable and a thermosetting resin (for example, epoxy resin or the like) is used for the adhesive layer of the base material for a flat cable, The present inventors have found that voids are hardly generated between the conductors of the flat cable by defining the amount of needle insertion of the adhesive layer in the TMA needle insertion mode measurement to be within a specific range. Based on these findings, further research has been conducted and the present invention has been completed.

The present invention relates to the following polyimide films with adhesives and the like.

[1] An adhesive polyimide film having an oxygen index of 30% or more.

[2] The adhesive-attached polyimide film according to [1], wherein the thickness of the adhesive layer is 0.25 to 2.3 times the thickness of the polyimide film.

[3] The needle insertion amount at 100 캜 of the TMA needle insertion mode measurement of the adhesive layer is 10% or less of the thickness of the adhesive layer, and / or the needle insertion amount at 140 캜 of the TMA needle insertion mode measurement of the adhesive layer, The adhesive-attached polyimide film according to [1] or [2], wherein the adhesive layer has a thickness of 20% or more.

[4] The adhesive-attached polyimide film according to any one of [1] to [3], wherein the needle insertion amount at 180 ° C. of the TMA needle insertion mode measurement of the adhesive layer is 40% or more of the thickness of the adhesive layer.

[5] The method according to any one of [1] to [4], wherein the polyimide film comprises at least one aromatic diamine component selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether and 3,4'- diaminodiphenyl ether and pyromellitic dianhydride The adhesive-attached polyimide film according to any one of [1] to [4], wherein the raw material contains an aromatic acid anhydride component of water and / or 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride.

[6] The adhesive-attached polyimide film according to any one of [1] to [5], wherein the adhesive layer contains an adhesive component containing an epoxy resin and an additive containing another resin.

[7] The adhesive-attached polyimide film according to any one of [1] to [6], wherein the adhesive layer does not substantially contain a flame retardant.

[8] An adhesive-attached polyimide film according to any one of [1] to [7], which is used for manufacturing a flat cable.

[9] A flat cable in which conductors are sandwiched by a polyimide film with an adhesive as described in any one of [1] to [8].

The polyimide film (polyimide film with adhesive) of the present invention is excellent in flame retardancy despite having an adhesive layer. Particularly, such a polyimide film exhibits high flame retardancy even when the adhesive layer does not substantially contain a flame retardant or a flame retarding additive (for example, a metal hydrate, an antimony compound, a halogen compound, etc.). In addition, even when halogen is not substantially contained, excellent flame retardancy can be realized. Therefore, it is possible to soften the polyimide film with an adhesive with a non-halogen (halogen-free) without impairing the physical properties such as the dielectric constant, and is very useful.

Further, the adhesive-attached polyimide film of the present invention is excellent in heat resistance and dimensional stability due to heat. Therefore, it can be used efficiently even at a high temperature (for example, 180 ° C or more) which can not be used for a PET film or the like.

Further, in the polyimide film with an adhesive of the present invention, bubble generation can be effectively suppressed or prevented. Therefore, for example, it is possible to effectively suppress or prevent the gap generated between the conductors.

As described above, the polyimide film with adhesive of the present invention has the above-described excellent properties, and in particular, when used in a flat cable (base material for a flat cable), a flat cable of high performance can be obtained. The flat cable is used, for example, for various electric devices (for example, a television, a mobile phone, a tablet, a personal computer), and particularly, for a FPD (flat panel display).

Hereinafter, the present invention will be described in more detail. The adhesive-attached polyimide film of the present invention is a polyimide film having an adhesive layer, and has a specific oxygen index. Such an adhesive-attached polyimide film usually has an adhesive layer on one side of the polyimide film. Further, the adhesive-attached polyimide film may have another layer on the side of the polyimide film side (the side where the adhesive layer is not provided on the polyimide film side).

[Polyimide film]

To obtain the polyimide film, first, a polyamic acid solution (hereinafter also referred to as a polyamic acid solution) is obtained by polymerizing an aromatic diamine component and an aromatic acid anhydride component in an organic solvent.

The polyamic acid solution can be obtained by polymerizing a chemical substance containing an aromatic diamine component and an aromatic acid anhydride component as main components in an organic solvent.

Examples of the aromatic diamine component include para-phenylenediamine, metaphenylenediamine, benzidine, para-xylenediamine, 4,4'-diaminodiphenyl ether, 3,4'- diaminodiphenyl ether, Diaminodiphenylmethane, 1,4-diaminodiphenylmethane, 1,5-diaminodiphenylmethane, 1,5-diaminodiphenylmethane, 1,4-diaminodiphenylmethane, Dimethoxybenzidine, 1,4-bis (3-methyl-5-aminophenyl) benzene, and amide-forming derivatives thereof. These may be used alone or in combination of two or more.

As the aromatic diamine component, from the viewpoints of excellent heat resistance of the adhesive-attached polyimide film and excellent dimensional stability by heat resistance and heat when a flat cable is formed, paraphenylenediamine, 4,4'-diaminodiphenyl ether And 3, 4'-diaminodiphenyl ether, and a combination of paraphenylenediamine and 4,4'-diaminodiphenyl ether is more preferable.

The raw materials used for forming the polyamic acid solution may contain diamine components other than the aromatic diamine component within the range not hindering the effect of the present invention. Examples of other diamine components include 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylpropane, 3,4'-diaminodiphenylpropane, 3,3'-diaminodi Phenylpropane, 3, 4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, Diaminodiphenylsulfone, 2,6-diaminopyridine, bis- (4-aminophenyl) diethylsilane, bis- (4-aminophenyl) (4-aminophenyl) phenylphosphine oxide, bis- (4-aminophenyl) -N-phenylamine, bis Diaminobiphenyl, 3,4'-dimethyl-3 ', 5'-dimethyl-3', 5'-diaminobiphenyl, Bis (p-? -Amino-t-butylphenyl) ether, bis (p-? -Amino-t-butyl (1, 1-dimethyl-5-aminopentyl) benzene, m-xylenediamine, p-xylenediamine, p-bis Diaminocycloheptane, diaminoamantane, 3,3'-diamino-1,1'-diaminoamantane, 3,3'-diaminomethyl-1,1'-diadamantane, bis (p- aminocyclohexyl) But are not limited to, methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 3-methylheptamethylenediamine, 4,4'-dimethylheptamethylenediamine, 2-ethylhexylamine, 2-ethylhexylamine, 2-bis (3-aminopropoxy) ethane, Diaminocyclohexane, 1,2-diaminooctadecane, 2,5-diamino-1,3,4-oxadiazole, 2,2-bis (4-aminophenyl) hexa Fluoropropane, N- (3-aminophenyl) -4-aminobenzo Amide, 4-aminophenyl-3-aminobenzoate, and the like. These may be used alone or in combination of two or more.

Specific examples of the aromatic acid anhydride component include pyromellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3', 3,4'-biphenyltetracarboxylic acid, 3,3 ' , 2,4,4-benzophenonetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5,6-tetra Acid anhydride components of aromatic tetracarboxylic acids such as carboxylic acids and their amide-forming derivatives. These may be used alone or in combination of two or more.

As the aromatic acid anhydride component, pyromellitic acid dianhydride and / or 3, 3 ', 4', 4 ', 4'- , 4'-biphenyltetracarboxylic acid dianhydride is preferable.

In the present invention, the raw material used for forming the polyamic acid solution may contain an acid anhydride component other than the aromatic acid anhydride component, so long as the effect of the present invention is not hindered. Other acid anhydride components include, for example, 1,2,4,5-naphthalenetetracarboxylic acid dianhydride, 1,4,8-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-decahydronaphthalenetetra Carboxylic acid dianhydride, 2,4,8-dimethyl-1,2,5,6-hexahydronaphthalenetetracarboxylic acid dianhydride, 2,6-dichloro-1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2,7- 1, 4, 5, 8-naphthalenetetracarboxylic acid dianhydride, 1,2,3,6,7-tetrachloro-1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,8,9,10- (2, 3-dicarboxyphenyl) propane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1- Bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, bis Water, benzene-1,2,3,4-tetracarboxylic Acid dianhydride, and 3,4, 3 ', 4'-benzophenone tetracarboxylic acid dianhydride. These may be used alone or in combination of two or more.

Further, the aromatic diamine component and / or the aromatic acid anhydride component may be a non-halogen component (component not containing a halogen).

In the present invention, examples of the combination of the aromatic diamine component and the acid anhydride component include at least one compound selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 3,4'- diaminodiphenyl ether Particularly preferred are combinations of aromatic diamine components, pyromellitic dianhydride and / or aromatic acid anhydride components of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride.

When the aromatic diamine component comprises para-phenylenediamine and 4, 4'-diaminodiphenyl ether, the molar ratio of paraphenylenediamine to 4,4'-diaminodiphenyl ether is 50/50 to 0/100 , More preferably from 40/60 to 0/100.

When the aromatic acid anhydride component contains pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, the pyromellitic dianhydride and the 3,3', 4,4'-biphenyltetra The molar ratio of the carboxylic acid dianhydride is preferably 100/0 to 50/50, more preferably 100/0 to 60/40.

Specific examples of the organic solvent used for forming the polyamic acid solution include sulfoxide-based solvents such as dimethylsulfoxide and diethylsulfoxide, N, N-dimethylformamide, N, N-diethylformamide Amide and the like, acetamide-based solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, N-methyl-2-pyrrolidone, N- , Phenol solvents such as phenol, o-, m- or p-cresol, xylenol, halogenated phenol and catechol, non-proton such as hexamethylphosphoramide and? -Butylolactone, A polar solvent, and the like. These may be used alone or in combination of two or more, and may be used in combination with aromatic hydrocarbons such as xylene and toluene.

The polymerization of the polyamic acid solution can be carried out by any known method. For example,

(1) a method in which all the aromatic diamine components are added to a solvent, and then an aromatic acid anhydride component is added so as to be equivalent to the total amount of the aromatic diamine components,

(2) a method in which all the components of the aromatic acid anhydride are first added to a solvent and then an aromatic diamine component is added so as to be equivalent to the aromatic acid anhydride component,

(3) a part of the aromatic diamine component is added to the solvent, and then the aromatic diamine component is added to the reaction component in such a ratio that the aromatic acid anhydride component is 95 to 105 mol% And then adding a part of the other aromatic acid anhydride component so that the wholly aromatic diamine component and the wholly aromatic acid anhydride component are almost equivalent,

(4) After adding a part of the aromatic acid anhydride component to the solvent, the reaction mixture is mixed for a time required for the reaction in such a proportion that a part of the aromatic diamine component accounts for 95 to 105 mol%, and then a part of the aromatic acid anhydride component Followed by addition of another aromatic diamine component such that the wholly aromatic diamine component and the wholly aromatic anhydride component are almost equivalent,

(5) The polyamic acid solution (A) is adjusted by reacting a part of the aromatic diamine component and the aromatic acid anhydride component in the solvent so as to be excessive, and the aromatic diamine component and the aromatic acid anhydride component Is reacted with excess to adjust the polyamic acid solution (B). The polyamic acid solutions (A) and (B) thus obtained are mixed to complete the polymerization. In this case, when the aromatic diamine component is excessive in the preparation of the polyamic acid solution (A), the aromatic acid anhydride component is excessively used in the polyamic acid solution (B) and the aromatic acid anhydride component is excessively used in the polyamic acid solution (A) , The polyamic acid solution (B) is made to have an excess of the aromatic diamine component and the polyamic acid solution (A) and the polyamic acid solution (B) are mixed to adjust the wholly aromatic diamine component and the wholly aromatic acid anhydride component , And the like. The polymerization method is not limited to these, and other known methods may be used.

In the present invention, the aromatic acid anhydride component and the aromatic diamine component constituting the polyamic acid are polymerized in such a ratio that the molar numbers of the aromatic acid anhydride and the aromatic diamine are approximately equal to each other, but one of them is contained in an amount of 10 mol% May be blended in excess.

The polymerization reaction is preferably carried out while stirring in an organic solvent. The polymerization temperature is not particularly limited, but is usually carried out at an internal temperature of the reaction solution at 0 to 80 캜. The polymerization time is not particularly limited, but it is preferably carried out continuously for 10 minutes to 30 hours. The polymerization reaction may be carried out by dividing the polymerization reaction or raising or lowering the temperature if necessary. The order of adding the two reactants is not particularly limited, but it is preferable to add an aromatic acid anhydride to the solution of the aromatic diamine component. Vacuum defoaming during the polymerization reaction is an effective method for producing an organic solvent solution of high quality polyamic acid. Further, it is also possible to control the polymerization reaction by adding a small amount of end-capping agent to the aromatic diamines before the polymerization reaction. The terminal sealing agent is not particularly limited and a known one can be used.

The polyamic acid solution thus obtained contains 5 to 40% by weight, preferably 10 to 30% by weight, of the solid content. The viscosity is a value measured by a Brookfield clay system, and is not particularly limited, but is usually from 10 to 2000 Pa · s (100 to 20000 poise), and preferably from 100 to 1000 Pa · s )to be. Moreover, the polyamic acid of the organic solvent solution may be partially imidized.

By heating the polyamic acid solution, a polyimide film can be produced.

As a method for producing the polyimide film, for example, there are a method of casting a polyamic acid solution into a film form and thermally depolarizing and desolvating the polyimide film, a method of mixing a polyamic acid solution with a cyclization catalyst and a dehydrating agent, To prepare a gel film and subjecting it to a thermal desolvation to obtain a polyimide film. The latter method is preferable.

In the method of chemically de-catalyzing, the polyamic acid solution is first prepared. The polyamic acid solution may contain a cyclization catalyst (imidization catalyst), a dehydrating agent and a gelling retarder.

Specific examples of the cyclization catalyst include aliphatic tertiary amines such as trimethylamine and triethylenediamine; aromatic tertiary amines such as dimethylaniline; and heterocyclic tertiary amines such as isoquinoline, pyridine and? -Picoline. These may be used alone or in combination of two or more. Among them, it is preferable to use at least one heterocyclic tertiary amine.

Specific examples of the dehydrating agent include an aliphatic carboxylic acid anhydride such as anhydrous acetic acid, anhydrous propionic acid and anhydrous lactic acid, and an aromatic carboxylic acid anhydride such as anhydrous benzoic acid. Of these, acetic anhydride and / or benzoic anhydride are preferable.

As a method for producing a polyimide film from a polyamic acid solution, for example, a polyamic acid solution containing a cyclization catalyst and a dehydrating agent is flowed (flexible) into a film form on a support from a slit attachment inlet or the like, Imidization is partially proceeded to form a gel film having self-supporting property, then the film is peeled off from the support and subjected to a heat treatment to obtain a polyimide film.

The polyamic acid solution flows on a heated support and undergoes a ring-closing reaction on the support to form a gel film having self-supporting properties and peeled from the support.

The support is a metal rotary drum or an endless belt, the temperature of which is controlled by the heat of the liquid or gas, and / or the radiant heat of an electric heater or the like.

The gel film is heated to a temperature of usually 30 to 200 ° C, preferably 40 to 150 ° C due to hydrothermal heat from a support and / or heat from a heat source such as hot air or an electric heater to cause a ring-closing reaction, By drying the volatile matter, it becomes self-supporting and is peeled from the support.

The gel film peeled off from the support is usually stretched in the running direction while regulating the traveling speed by a rotating roll. Stretching is usually carried out at a temperature of 140 DEG C or lower at a magnification of 1.01 to 1.90, preferably 1.05 to 1.60, and more preferably 1.10 to 1.50. The gel film stretched in the running direction is introduced into a tenter device, and both ends in the width direction are gripped on the tenter clip, and are stretched by the width method while traveling together with the tenter clip.

The stretched gel film is usually heated by wind, infrared heater or the like for 15 seconds to 30 minutes. Next, heat treatment is usually performed at a temperature of 250 to 500 占 폚 for 15 seconds to 30 minutes by hot air and / or an electric heater.

The thickness of the polyimide film can be adjusted by the running speed. The thickness of the polyimide film can be appropriately selected in accordance with the thickness of the intended laminated film, the number of polyimide films to be used, and the like.

The polyimide film thus obtained is preferably subjected to a coarse annealing treatment. The heat shrinkage is easily reduced effectively by the annealing treatment (concretely, for example, the heat shrinkage after heating at 200 DEG C for 60 minutes can be made 0.2% or less). The method of the annealing treatment is not particularly limited, and may be performed according to a conventional method. The temperature of the annealing treatment is not particularly limited, but is preferably 200 to 500 占 폚, more preferably 200 to 370 占 폚, and particularly preferably 210 to 350 占 폚. Specifically, it is preferable that the film is run under a storage force in the furnace heated to the above-mentioned temperature range, and annealing treatment is carried out. The time required for the film to stay in the furnace is the processing time, but it is controlled by changing the running speed, and it is preferable that the processing time is 5 seconds to 5 minutes. The film tension during running is preferably 10 to 50 N / m, more preferably 20 to 30 N / m.

The polyimide film may contain a filler (e.g., an inorganic particle, an organic filler or the like), and preferably contains an inorganic particle.

The content of the filler in the polyimide film is not particularly limited, but may be, for example, about 0.03 to 1% by weight, preferably about 0.05 to 0.8% by weight.

The method of adding the filler to the polyimide film is not particularly limited, but a filler may be added to the polyamic acid solution. The filler may be added to the pre-polymerized polyamic acid solution, or the polyamic acid solution may be polymerized in the presence of the filler.

In the polyimide film, the heat shrinkage ratio after heating at 200 캜 for 60 minutes is not particularly limited, but may be, for example, 0.2% or less (for example, 0.01 to 0.15%), preferably 0.15% , 0.01 to 0.1%), more preferably not more than 0.1% (for example, 0.01 to 0.07%). By using such a polyimide film, the heat shrinkage of the polyimide film with an adhesive can be easily reduced effectively. The heat shrinkage ratio of the polyimide film after heating at 200 캜 for 60 minutes was measured by using a CNC image processing apparatus system NEXIV VM-250 (Nikon Corporation) The film size (L2) after heating at 200 ° C for 60 minutes and then left in a room adjusted to 25 ° C and 60% RH for one day was measured using the CNC image processing apparatus system , It can be calculated by the following equation.

Heat shrinkage percentage (%) = - (L2-L1) / L1} x 100

The average linear expansion coefficient of the polyimide film is not particularly limited, but may be, for example, 0 to 100 ppm / ° C, preferably 0 to 50 ppm / ° C, more preferably 3 to 35 ppm / ° C. The thermal expansion coefficient can be measured using a TMA-50 manufactured by Shimadzu Corporation under the conditions of a measurement temperature range of 50 to 200 占 폚 and a temperature increase rate of 10 占 폚 / min.

The surface roughness Rmax of the polyimide film is preferably 0.6 占 퐉 or more (for example, 0.6 to 2 占 퐉), for example, from the viewpoint of improving the adhesiveness between the adhesive layer and the reinforcing plate which is opposite to the adhesive layer, ). The surface roughness Rz of the polyimide film is preferably 0.3 mu m or more (for example, 0.3 to 1.2 mu m) in view of improvement in adhesion with the adhesive layer and the like. The measurement of the surface roughness of the polyimide film may be in accordance with JIS B 0601 (2001).

The method for obtaining the polyimide film having such a surface roughness is not particularly limited, and for example, a known surface treatment (for example, wet blast treatment, sand mat treatment, resin mat treatment, plasma treatment or the like) Can be obtained. Furthermore, the surface treatment may be performed on one side or both sides of the polyimide film.

In the adhesive-attached polyimide film, the polyimide film may be substantially a non-halogen-based polyimide film (a halogen-free polyimide film), and substantially the same as the adhesive layer described later, Or a polyimide film containing no polyimide.

[Adhesive layer]

The adhesive is not particularly limited as long as it can form an adhesive layer, but usually includes an adhesive component.

As the adhesive component, for example, a thermoplastic resin (for example, a polyamide resin or the like), a thermosetting resin (for example, an unsaturated polyester resin, an epoxy resin or the like) .

The adhesive layer may contain additives insofar as the adhesiveness is not impaired. As the additive, for example, a resin which is not included in the category of a flame retardant (or a flame retarder), an antioxidant, a crosslinking agent, and an adhesive component (hereinafter also referred to simply as "another resin"). (For example, a styrene-based linear raster, etc.)}, and the like. In particular, although the adhesive layer may contain a flame retardant (including a flame retardant auxiliary), it may be substantially free of a flame retardant. In the present invention, excellent flame retardancy can be exhibited even if the flame retardant is not substantially contained in the adhesive layer.

Examples of the flame retardant (including the flame retardant auxiliary) include general-purpose components such as metal hydrates (for example, metal hydroxides such as magnesium hydroxide, aluminum hydroxide, calcium hydroxide, barium hydroxide, Alkaline magnesium carbonate, etc.], halogen compounds (e.g., halogen-containing low-molecular compounds (decabromodiphenyl ether, halogenated bisphenol A and the like), halogen-containing resins (for example, epoxy resins ), Antimony compounds (e.g., antimony trioxide), phosphorus compounds (e.g., phosphorus-containing oligomers, ammonium phosphate, and trisdiphenylphosphinic acid aluminum).

The adhesive layer may contain a solvent (for example, an aromatic hydrocarbon solvent such as toluene or xylene, a ketone solvent such as methyl ethyl ketone or dimethyl ketone).

In the adhesive layer, the additive (particularly, an additive that is not a flame retardant) is added in an amount of, for example, 1.5 to 200 parts by weight (for example, 2 to 170 parts by weight) (For example, 3 to 140 parts by weight), more preferably 3 to 120 parts by weight (for example, 5 to 100 parts by weight).

Particularly, with respect to the flame retardant, it is preferable that the level of the flame retardant is not substantially contained even if the adhesive layer contains the flame retardant. For example, the proportion of the flame retarder is preferably 20% Or less, preferably 10 wt% or less, more preferably 5 wt% or less, particularly preferably 3 wt% or less.

Further, the adhesive layer may be substantially non-halogen-based (halogen-free, halogen-free).

[Adhesive Polyimide Film]

In the adhesive-attached polyimide film, the thickness (average thickness) of the polyimide film is, for example, 1 to 150 μm (for example, 3 to 125 μm), preferably 5 to 120 μm To 100 탆), and more preferably 10 to 80 탆 (for example, 15 to 50 탆).

In the adhesive-bonded polyimide film, the thickness (average thickness) of the adhesive layer is not particularly limited, but may be, for example, 300 탆 or less (for example, 1 to 250 탆) (For example, 2 to 180 탆), more preferably 150 탆 or less (for example, 3 to 120 탆), particularly 100 탆 or less (for example 5 to 80 탆) For example, 3 to 40 占 퐉, preferably 5 to 35 占 퐉, and more preferably 10 to 30 占 퐉.

In particular, the thickness (average thickness) of the adhesive layer is preferably not too large with respect to the total thickness of the adhesive-attached polyimide film. For example, the thickness of the polyimide film (polyimide film without the adhesive layer) (For example, 0.05 to 2.4 times), preferably not more than 2.3 times (for example, 0.05 to 2.4 times), for example, (For example, 0.1 to 2.2 times), more preferably twice or less (for example, 0.15 to 1.8 times), particularly 1.5 times or less (for example, 0.2 to 1.2 times) It is okay to ship.

By adjusting the thickness of the adhesive layer as described above, it is easy to obtain a polyimide film with an adhesive excellent in flame retardance and the like.

The thickness (average thickness) of the adhesive layer may be more than 1/2 of the thickness of the conductor in consideration of the embeddability of the conductor. In this case, it is preferable from the viewpoint that the embedding of the conductor becomes sufficient, and a gap is not easily generated between the conductors.

The adhesive-attached polyimide film of the present invention is excellent in flame retardancy.

For example, the oxygen index of the adhesive-loaded polyimide film of the present invention can be selected from a range of 25% or more (for example, 27 to 90%), for example, 30% or more (For example, 42 to 70%), particularly 45% or more (for example, 46% to 80%), preferably 35% ~ 65%).

The oxygen index can be measured in accordance with, for example, JIS K7201-2.

The adhesive layer of the adhesive-attached polyimide film can adjust the needle insertion amount in the TMA needle insertion mode measurement to a specific range.

For example, the adhesive layer of the adhesive-attached polyimide film has a needle insertion amount (invasion ratio) of 100% or less of the thickness of the adhesive layer in the TMA needle insertion mode measurement of 10% or less , 0 to 8%), preferably not more than 7% (for example, from 0.1 to 6%), more preferably not more than 6% (for example, from 0.3 to 5.5% , 0.5 to 5%).

The needle insertion amount (invasion ratio) with respect to the thickness of the adhesive layer is represented by (B / A) x 100 (%) when the thickness of the adhesive layer is A (占 퐉) and the penetration amount is B .

The adhesive layer of the adhesive-attached polyimide film is preferably such that the needle insertion amount (invasion ratio) at 140 캜 with respect to the thickness of the adhesive layer in the TMA needle insertion mode measurement is 5% or more (for example, 7 (For example, 15 to 88%), preferably 20% or more (for example, 20 to 85%), and more preferably, 25% or more (for example, 26 to 80%) may be satisfied.

The adhesive layer of the adhesive-bonded polyimide film has a needle insertion amount (invasion ratio) at 180 캜 of 20% or more (for example, 22 to 95 %) (For example, 27 to 92%), preferably 30% or more (for example, 35 to 90%), more preferably 40% (For example, 42 to 88%), particularly 45% or more (for example, 50 to 85%).

By adjusting the amount of needle insertion at each temperature as described above, flame retardancy, heat resistance, dimensional stability, bubble generation amount between conductors, and the like can be efficiently adjusted.

In addition, the needle insertion amount at each temperature (100 DEG C, 140 DEG C, 180 DEG C) of the TMA needle insertion mode measurement was measured using a TMA measuring apparatus at a heating rate of 10 DEG C / minute to 200 DEG C (100 ° C., 140 ° C., 180 ° C.) with respect to the thickness of the adhesive layer, and the penetration depth (penetration amount, unit: μm) of the indenter was read to each temperature (100 ° C., 140 ° C., 180 ° C.) Of the penetration depth of the indenter. As the TMA measuring device, a thermal analyzer (TMA-60) manufactured by Shimadzu Corporation can be used.

The adhesive-attached polyimide film can be obtained, for example, by applying an adhesive to one side or both sides of a polyimide film and drying it. The method of application and drying is not particularly limited.

[Flat cable]

The adhesive-attached polyimide film of the present invention can be used particularly in the production of a flat cable.

The method of producing the flat cable is not particularly limited, and may be a method in which the conductor is sandwiched (sandwiched) with two (a pair of) adhesive-adhered polyimide films. In a flat cable, a conductor is usually sandwiched between adhesive layers of a polyimide film with an adhesive. The flat cable can be produced, for example, by inserting a conductor row in which a plurality of conductors are arranged in the same plane, with the adhesive layers of the adhesive-attached polyimide film interposed therebetween. Further, when the conductor is sandwiched between the adhesive-attached polyimide films, heating, pressing, and the like may be performed.

Examples of the conductor include, but are not particularly limited to, flat copper foil of a conductive metal, a round wire, a rectangular conductor having a rectangular cross section, and an organic conductor. The conductive metal is not particularly limited, and copper, silver, tin, indium, aluminum, molybdenum, an alloy thereof, or the like may be used. The width and thickness of the conductor are not particularly limited.

The flat cable may have a reinforcing plate. As the reinforcing plate, for example, a polyimide film or a laminate of a plurality of (for example, two to three) polyimide films may be used. A method of laminating a plurality of polyimide films is not specified, but a method of laminating only a polyimide film or a method of laminating a polyimide film through another layer (for example, an adhesive layer or the like) may be used. The constitution and physical properties of the polyimide film in this case are not particularly limited. The thickness of the reinforcing plate may be, for example, about 50 to 500 占 퐉 (for example, 75 to 300 占 퐉 or the like). Further, the reinforcing plate may be laminated on one side of the flat cable or on both sides thereof.

The flat cable of the present invention is excellent in dimensional stability due to heat and has a heat shrinkage rate (dimensional change ratio) of 0.2% or less (for example, 0.01 to 0.15%) after heating at 180 ° C for 10 minutes, 0.15% or less (for example, 0.01 to 0.13%).

[Example]

The present invention will now be described more specifically with reference to Examples, but it should be understood that the present invention is not limited to these Examples, and many variations are possible within the technical scope of the present invention, Lt; / RTI >

[Polyamic acid Synthesis Example A]

(Molecular weight: 218.12) / 4,4'-diaminodiphenyl ether (molecular weight: 200.24) in a molar ratio of 1: 1, and 20% by weight of DMAc (N, N-dimethylacetamide) Solution to obtain a polyamic acid solution of 4000 poise.

[Polyamic acid Synthesis Example B]

Biphenyltetracarboxylic dianhydride (molecular weight: 294.22) / 4,4'-diaminodiphenyl ether (molecular weight: 200.24) / p-phenylenediamine (Molecular weight: 108.14) was prepared at a molar ratio of 60/40/80/20 and polymerized with a 20 wt% solution in DMAc (N, N-dimethylacetamide) to obtain a polyamic acid solution of 4000 poise.

[Measurement of Oxygen Index]

And measured according to JIS K7201-2. The adhesive-attached polyimide film was cut into a size of 150 mm x 20 mm and burned using an oxygen index type flammability tester manufactured by Suga Tester Co., Ltd.

[Heat shrinkage of polyimide film]

The heat shrinkage ratio of the polyimide film after heating at 200 DEG C for 60 minutes was measured by using a CNC image processing apparatus system NEXIVVM-250 (manufactured by Nikon Corporation) after the film was left in a room adjusted to 25 DEG C and 60% ), Then measuring the film size (L2) after heating at 200 占 폚 for 60 minutes and then left in a room adjusted to 25 占 폚 and 60% RH for one day, using the CNC image processing apparatus system, Was calculated by the following formula.

Heat shrinkage percentage (%) = - (L2-L1) / L1} x 100

[Surface roughness of polyimide film]

The surface roughness of the polyimide film was measured according to JIS B 0601 (2001). Surface roughnesses Rmax and Rz were measured under the following conditions using a contact type surface roughness meter.

Cut-off value: 0.25 mm, measurement length: 2 mm, radius of tip of stylus tip: 2 m

[Needle insertion rate]

The adhesive-loaded polyimide film was cut into a size of 10 mm x 10 mm, and the penetration mode was measured at a heating rate of 10 캜 / minute to 200 캜 at a constant load of 50 gf using a thermal analyzer (TMA-60) manufactured by Shimadzu Corporation And the penetration depth (insertion amount, unit: 占 퐉) of the indenter up to 100 占 폚, 140 占 폚 and 180 占 폚 was read. The ratio of the thickness of the adhesive layer to the thickness of the adhesive layer was calculated from the read values. The indenter used was a cylindrical shape with a tip diameter of 0.5 mm, and the surface of the adhesive was used as an indentation surface.

[Purchase property]

The presence of air bubbles between the flat cable conductors was checked visually, and the length of the air bubbles was measured. The ratio of the length of the position where the bubbles were generated to the length of the flat cable was calculated to be the bubble generation rate.

[Heat shrinkage of flat cable (rate of dimensional change)]

The produced flat cable was heated at 180 DEG C for 10 minutes and the inter-conductor dimension L3 before heating and the inter-conductor dimension L4 after heating were measured using a CNC image processor system NEXIV VM-250 (manufactured by Nikon Corporation) , And calculated according to the following formula.

Heat shrinkage percentage (%) = - (L4-L3) / L3} 100

[Formation of polyimide film A]

N, N-dimethylacetamide slurry of calcium phosphate of 81.5% by volume of particles having an average particle diameter of 0.87 mu m and a particle diameter of 0.5 to 2.5 mu m, Was added to the polyamic acid solution obtained in Synthesis Example A in an amount of 0.15% by weight based on the weight of the resin, and sufficiently stirred and dispersed. To the polyamic acid solution was added 2.0 molar equivalents of a dialcoholic anhydride (molecular weight: 102.09) and a dialking agent composed of? -Picoline to the polyamic acid, and the mixture was stirred. The obtained mixture was cast from the inlet onto a rotatable stainless steel drum at 65 DEG C to obtain a gel film having magnetic supportability. The gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 250 캜 for 30 seconds, 400 캜 for 30 seconds, and then at 550 캜 for 30 seconds. The obtained film was annealed in a heating furnace at 300 占 폚 for 1 minute to obtain a polyimide film having a thickness of 25 占 퐉, Rmax of 0.8 占 퐉 and Rz of 0.5 占 퐉.

[Formation of polyimide film B]

One surface of the polyimide film A was subjected to a sand matting treatment to obtain a polyimide film B having a thickness of 25 占 퐉, a Rmax of 1.4 占 퐉 and a Rz of 1.0 占 퐉 on the sand matte-treated surface. The sand matting treatment was carried out by attaching particles having a sand particle diameter distribution of 80 to 200 mu m in diameter to the surface of the film.

[Formation of polyimide film C]

A polyimide film C was produced in the same manner as the polyimide film A except that the polyamic acid solution obtained in Synthesis Example B was used instead of the polyamic acid solution obtained in Synthesis Example A. [ The thickness of the obtained polyimide film C was 25 占 퐉, Rmax was 0.8 占 퐉 and Rz was 0.5 占 퐉.

Example 1

[glue]

10 parts by weight of EPICLON HP-7200 (dicyclopentadiene skeleton-containing epoxy resin, manufactured by DIC Co., Ltd.), 100 parts by weight of Tuftec M1913 (Asahi Chemical Industry Co., Ltd., maleic acid-modified styrene ethylene block copolymer) (Manufactured by Shikoku Kasei Co., Ltd.) and 420 parts by weight of toluene were mixed to prepare an adhesive.

[Adhesive Polyimide Film]

The above-mentioned adhesive was applied to one side of the obtained polyimide film A and dried at 90 DEG C for 3 minutes to obtain an adhesive-attached polyimide film. In the adhesive-attached polyimide film, the thickness of the adhesive layer was 25 占 퐉.

[Fabrication of Flat Cable Samples]

51 conductors having a width of 0.30 mm and a thickness of 0.035 mm were arranged at an inter-conductor pitch of 0.50 mm at the adhesive layer side of the polyimide film with adhesive and another adhesive layer side of another polyimide film with adhesive And pressed at 180 DEG C and 0.5 MPa with a heat roll to produce a flat cable.

Example 2

A flat cable was produced in the same manner as in Example 1 except that the polyimide film B was used in place of the polyimide film A and the adhesive was applied to the sand matte surface of the polyimide film B.

Example 3

In the adhesive, jER828 (Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation) was used instead of EPICLON HP-7200, TD773 (Novolac type phenol resin, manufactured by DIC Co., Ltd.) was used instead of Tuftec M1913, Was made to have a thickness of 20 탆, a flat cable was produced in the same manner as in Example 1.

Example 4

YDCN-700-3 (cresol novolak epoxy resin, manufactured by Shin-Nitetsu Sumiken Chemical Co., Ltd.) was used instead of EPICLON HP-7200, and Nipol 1072J (manufactured by Nippon Zeon Co., And a thickness of the polyimide film was adjusted to be 12.5 占 퐉. In the same manner as in Example 1, a flat cable was produced.

Example 5

A flat cable was produced in the same manner as in Example 1, except that the drying conditions for applying and drying an adhesive on one side of the polyimide film were changed to 130 占 폚 for 10 minutes.

Example 6

An adhesive-attached polyimide film and a flat cable were produced in the same manner as in Example 1 except that the polyimide film C was used instead of the polyimide film A.

Reference Example 1

A flat cable was produced in the same manner as in Example 1 except that the adhesive layer had a thickness of 60 탆.

Table 1 shows the physical properties of the polyimide film and the flat cable obtained in the respective Examples and Reference Examples.

Polyimide film Adhesive layer Adhesive-attached polyimide film Thickness (㎛)
Heat shrinkage (%) Thickness (㎛)
Thickness (times)
Needle insertion ratio (%) to adhesive layer thickness Oxygen Index (%) Heat shrinkage (%)
Bubble generation rate (%)
100 ℃ 140 ° C 180 DEG C Example 1 25 0.03 25 One 2 52 72 48 0.05 One Example 2 25 0.06 25 One 2 52 72 50 0.08 One Example 3 25 0.03 20 0.8 5 75 80 53 0.05 2 Example 4 12.5 0.03 25 2 0.8 28 52 37 0.05 3 Example 5 25 0.03 25 One 0 8 28 48 0.05 30 Example 6 25 0.01 25 One 2 52 72 53 0.02 One Reference Example 1 25 0.03 60 2.4 8.3 77 83 20 0.05 One

The adhesive-attached polyimide film of the examples had an oxygen index of at least 37%. In addition, the heat shrinkage ratio (dimensional change ratio) at 180 ° C could be made as small as 0.08% at the maximum. Further, in Examples 1 to 4 and 6, generation of air bubbles between conductors was reduced.

On the other hand, the adhesive-attached polyimide film of Reference Example 1 had an oxygen index of 20% and a low flame retardancy.

The adhesive-attached polyimide film of the present invention has excellent flame retardancy and can be preferably used as a flat cable.

Claims (9)

An adhesive index polyimide film having an oxygen index of 30% or more.
The adhesive-attached polyimide film according to claim 1, wherein the thickness of the adhesive layer is 0.25 to 2.3 times the thickness of the polyimide film.
The method of claim 1 or 2, wherein the needle insertion amount at 100 캜 of the TMA needle insertion mode measurement of the adhesive layer is 10% or less of the thickness of the adhesive layer and / or the TMA needle insertion mode measurement at 140 캜 of the TMA needle insertion mode measurement of the adhesive layer Wherein the needle insertion amount is 20% or more of the thickness of the adhesive layer.
The adhesive-attached polyimide film according to any one of claims 1 to 3, wherein the needle insertion amount at 180 캜 of the TMA needle insertion mode measurement of the adhesive layer is 40% or more of the thickness of the adhesive layer.
The polyimide film according to any one of claims 1 to 4, wherein the polyimide film is at least one selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 3,4'- diaminodiphenyl ether An adhesive-attached polyimide film comprising an aromatic diamine component and pyromellitic dianhydride and / or an aromatic acid anhydride component of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride in a raw material.
The adhesive polyimide film according to any one of claims 1 to 5, wherein the adhesive layer comprises an adhesive component containing an epoxy resin and an additive containing another resin.
The adhesive polyimide film according to any one of claims 1 to 6, wherein the adhesive layer substantially contains no flame retardant.
The adhesive-coated polyimide film according to any one of claims 1 to 7, for use in the production of a flat cable.
A flat cable in which conductors are sandwiched between a pair of polyimide films with an adhesive according to any one of claims 1 to 8.