JP2018059060A - Polyimide film with adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide film excellent in fire retardancy and useful for manufacturing of a flat cable or the like even having an adhesive layer.SOLUTION: A polyimide film has an adhesive and oxygen index of 30% or more. The polyimide film with adhesive has an adhesive layer which satisfies needle penetration amount at 100°C of 10% or less and/or needle penetration amount at 140°C of 20% or more, in the needle penetration amount to thickness of the adhesive layer in a TMA needle penetration mode measurement.SELECTED DRAWING: None

Description

  The present invention provides a polyimide film with an adhesive useful for manufacturing a flat cable manufactured by sandwiching a conductor between two substrates having an adhesive layer and an insulator layer, and the polyimide film with an adhesive. The constructed flat cable is related.

  Flat cables are widely used in electrical devices such as televisions, mobile phones and tablets, and hard disks for personal computers. In a flat cable, a conductor such as a copper foil formed in a wiring shape is arranged between a base material having an insulator layer and an adhesive layer (or simply referred to as a “flat cable base material”), and the base material. It is manufactured by sandwiching with an adhesive layer.

  Such a flat cable is required to have high flame retardancy, and a technique for improving the flame retardance of the flat cable is being developed.

  Patent Document 1 discloses a flat cable formed by sandwiching a plurality of conductors in parallel between two insulating substrates each having an insulating film layer and an adhesive layer, with each adhesive layer inside, and heat-sealing. In the film, the insulating film layer of the insulating substrate has an aromatic ring in the molecular skeleton, does not contain halogen, and is formed of an aromatic polymer (such as polyimide) having a critical oxygen index of 30% or more. And the halogen-free flame retardant flat cable which the adhesive bond layer contains metal hydrate 50-200 weight part with respect to 100 weight part of base polymers, and consists of a halide-free composition is disclosed.

JP-A-5-217430

  The objective of this invention is providing the flat cable comprised with the polyimide film (base material) with an adhesive agent excellent in the flame retardance, and this polyimide film.

  Another object of the present invention is to provide a polyimide film with an adhesive having excellent heat resistance (and dimensional stability due to heat) and a flat cable made of the polyimide film.

  Still another object of the present invention is to provide a polyimide film with an adhesive capable of efficiently suppressing or preventing the generation of bubbles and a flat cable composed of the polyimide film.

  Among the base film used for the flat cable, the present inventors focused on the polyimide film and examined a further flame retardant method in the polyimide film provided with the adhesive layer. It has been difficult to improve flame retardancy without using (for example, the metal hydrate of Patent Document 1).

  Under these circumstances, the present inventors have conducted further earnest studies, and as a result, regarding the polyimide film and the adhesive layer, the prescription and processing of the polyimide film can be selected, or the adhesive layer can be used for measuring the TMA needle mode. Despite having an adhesive layer by adjusting the amount of intrusion or adjusting the thickness ratio between the polyimide film and the adhesive layer, the adhesive layer is substantially free of flame retardants and flame retardant aids. Even if it is not used (even if it is non-halogen type), a polyimide film with an adhesive having a high oxygen index (that is, high flame retardancy) can be obtained. Has found that it has excellent heat resistance and dimensional stability due to heat.

Also, when a flat cable is formed by sandwiching a conductor with a flat cable base material and heating it, if a thermosetting resin (for example, epoxy resin) is used for the adhesive layer of the flat cable base material, the flat cable Although the air gap is likely to be generated between the conductors of the cable, the present inventors define the adhesive layer so that the amount of penetration into the needle of the TMA needle entering mode measurement is in a specific range, thereby preventing the gap between the conductors of the flat cable. It has been found that voids are less likely to occur.
Based on these findings, further research has been conducted and the present invention has been completed.

The present invention relates to the following polyimide film with an adhesive and the like.
[1] A polyimide film with an adhesive having an oxygen index of 30% or more.
[2] The polyimide film with an adhesive 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 amount of penetration into the needle at 100 ° C. of the adhesive layer in the TMA needle entering mode measurement is 10% or less of the thickness of the adhesive layer and / or the measurement of the adhesive layer in the TMA needle entering mode at 140 ° C. The polyimide film with an adhesive according to [1] or [2], wherein the penetration amount with a needle is 20% or more of the thickness of the adhesive layer.
[4] The polyimide with adhesive according to any one of [1] to [3], wherein the amount of penetration with a needle at 180 ° C. in the TMA needle entering mode measurement of the adhesive layer is 40% or more of the thickness of the adhesive layer. the film.
[5] The polyimide film is one or more aromatic diamine components selected from the group consisting of paraphenylenediamine, 4,4′-diaminodiphenyl ether and 3,4′-diaminodiphenyl ether, pyromellitic dianhydride and / or The polyimide film with an adhesive according to any one of [1] to [4], which contains, as a raw material, an aromatic acid anhydride component of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride.
[6] The polyimide film with an adhesive according to any one of [1] to [5], wherein the adhesive layer includes an adhesive component containing an epoxy resin and an additive containing another resin.
[7] The polyimide film with an adhesive according to any one of [1] to [6], wherein the adhesive layer does not substantially contain a flame retardant.
[8] The polyimide film with an adhesive according to any one of [1] to [7] for use in production of a flat cable.
[9] A flat cable in which a conductor is sandwiched between a pair of polyimide films with an adhesive according to any one of [1] to [8].

  The polyimide film (polyimide film with an adhesive) of the present invention is excellent in flame retardancy despite having an adhesive layer. In particular, such a polyimide film is highly difficult even if the adhesive layer does not substantially contain a flame retardant or a flame retardant aid (for example, metal hydrate, antimony compound, halogen compound, etc.). Shows flammability. Moreover, even if it does not contain a halogen substantially, the outstanding flame retardance is realizable. Therefore, it is possible to make the polyimide film with adhesive non-halogen (halogen-free) flame retardant without impairing physical properties such as dielectric constant, and is extremely useful.

  Moreover, the polyimide film with an adhesive of the present invention is excellent in heat resistance and dimensional stability due to heat. Therefore, for example, it can be used efficiently even at high temperatures (eg, 180 ° C. or higher) that cannot be used with PET films.

  Furthermore, in the polyimide film with an adhesive of the present invention, the generation of bubbles can be efficiently suppressed or prevented. Therefore, for example, the effect that the space generated between the conductors can be efficiently suppressed or prevented can be obtained.

Thus, the polyimide film with an adhesive of the present invention has excellent characteristics as described above. In particular, when used for a flat cable (a substrate for a flat cable), a high-performance flat cable is obtained. Can do.
As a flat cable, for example, it is used for various electric appliances (for example, a television, a mobile phone, a tablet, a personal computer), and may be used for an FPD (flat panel display).

Hereinafter, the present invention will be described in more detail.
The polyimide film with an adhesive of the present invention is a polyimide film provided with an adhesive layer and has a specific oxygen index. Such a polyimide film with an adhesive usually has an adhesive layer on one side of the polyimide film. In addition, the polyimide film with an adhesive may further include another layer on the polyimide film surface (the surface of the polyimide film where the adhesive layer is not provided).

[Polyimide film]
In obtaining a polyimide film, first, an aromatic diamine component and an aromatic acid anhydride component are polymerized in an organic solvent to obtain a polyamic acid solution (hereinafter also referred to as a polyamic acid solution).
The polyamic acid solution can be obtained by polymerizing a chemical substance mainly composed of an aromatic diamine component and an aromatic acid anhydride component in an organic solvent.

  Examples of the aromatic diamine component include paraphenylene diamine, metaphenylene diamine, benzidine, paraxylylene diamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 4, 4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 1,5-diaminonaphthalene, 3,3'-dimethoxybenzidine, 1,4-bis (3-methyl-5-amino Phenyl) benzene and their amide-forming derivatives. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As the aromatic diamine component, paraphenylenediamine, 4,4′-diamino is used from the viewpoint that the polyimide film with an adhesive is excellent in heat resistance and has excellent heat resistance and dimensional stability due to heat when a flat cable is formed. One or more selected from the group consisting of diphenyl ether and 3,4'-diaminodiphenyl ether is preferable, and a combination of paraphenylenediamine and 4,4'-diaminodiphenyl ether is more preferable.

As a raw material used for formation of a polyamic acid solution, you may contain other diamine components other than the said aromatic diamine component in the range which does not prevent the effect of this invention.
Examples of other diamine components include 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenylpropane, 3,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane, and 3,4′-diamino. Diphenylmethane, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenylsulfone, 3,3 ′ -Diaminodiphenylsulfone, 2,6-diaminopyridine, bis- (4-aminophenyl) diethylsilane, 3,3'-dichlorobenzidine, bis- (4-aminophenyl) ethylphosphinoxide, bis- (4- Aminophenyl) phenylphosphinoxide, bis- (4- Minophenyl) -N-phenylamine, bis- (4-aminophenyl) -N-methylamine, 1,5-diaminonaphthalene, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,4′-dimethyl -3 ′, 4-diaminobiphenyl-3,3′-dimethoxybenzidine, 2,4-bis (p-β-amino-t-butylphenyl) ether, bis (p-β-amino-t-butylphenyl) Ether, p-bis (2-methyl-4-aminopentyl) benzene, p-bis- (1,1-dimethyl-5-aminopentyl) benzene, m-xylylenediamine, p-xylylenediamine, 1,3 -Diaminoadamantane, 3,3'-diamino-1,1'-diaminoadamantane, 3,3'-diaminomethyl-1,1'-diadamantane, bis (p-aminocyclohexyl) ) Methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 3-methylheptamethylenediamine, 4,4'-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2 -Bis (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine, 3-methoxyhexaethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 5-methylnonamethylenediamine, 1 , 4-diaminocyclohexane, 1,12-diaminooctadecane, 2,5-diamino-1,3,4-oxadiazole, 2,2-bis (4-aminophenyl) hexafluoropropane, N- (3-amino Phenyl) -4-amino Nzuamido, 4-aminophenyl-3-aminobenzoate, and the like. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  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 ′, 4,4′-benzophenonetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5 Examples thereof include acid anhydride components of aromatic tetracarboxylic acids such as 6-tetracarboxylic acid and amide-forming derivatives thereof. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As an aromatic acid anhydride component, pyromellitic dianhydride and / or pyromellitic acid dianhydride and / or from the viewpoint of excellent heat resistance of a polyimide film with an adhesive and excellent heat resistance and dimensional stability due to heat when a flat cable is formed. Alternatively, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is preferable.

In this invention, as a raw material used for formation of a polyamic acid solution, you may contain other acid anhydride components other than the said aromatic acid anhydride component in the range which does not prevent the effect of this invention.
Examples of other acid anhydride components include 1,2,4,5-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,4,5,8, and the like. -Decahydronaphthalene tetracarboxylic dianhydride, 4,8-dimethyl-1,2,5,6-hexahydronaphthalene tetracarboxylic dianhydride, 2,6-dichloro-1,4,5,8-naphthalene Tetracarboxylic dianhydride, 2,7-dichloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-tetrachloro-1,4,5,8-naphthalenetetra Carboxylic dianhydride, 1,8,9,10-phenanthrenetetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1,1-bis (3,4 -Dicarboxyphenyl Ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane Dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ′, 4′-benzophenonetetracarboxylic acid A dianhydride etc. are mentioned. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

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

  In the present invention, the combination of the aromatic diamine component and the acid anhydride component includes at least one aromatic diamine component selected from the group consisting of paraphenylenediamine, 4,4′-diaminodiphenyl ether and 3,4′-diaminodiphenyl ether. And a combination of pyromellitic dianhydride and / or an aromatic acid anhydride component of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is particularly preferable.

  When the aromatic diamine component contains paraphenylene diamine and 4,4′-diaminodiphenyl ether, the molar ratio of paraphenylene diamine to 4,4′-diaminodiphenyl ether is preferably 50/50 to 0/100, More preferably, it is / 60 to 0/100.

  When the aromatic acid anhydride component comprises pyromellitic dianhydride and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride and 3,3 ′, 4,4 The molar ratio of '-biphenyltetracarboxylic 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 solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide. Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m-, or Examples thereof include phenolic solvents such as p-cresol, xylenol, halogenated phenol and catechol, and aprotic polar solvents such as hexamethylphosphoramide and γ-butyrolactone. These can be used singly or in combination of two or more, and further can be used in combination with aromatic hydrocarbons such as xylene and toluene.

The polymerization method of the polyamic acid solution may be performed by any known method, for example,
(1) A method in which an aromatic diamine component total amount is first put in a solvent, and then an aromatic acid anhydride component is added so as to be equivalent to the aromatic diamine component total amount, followed by polymerization,
(2) A method in which the entire amount of the aromatic acid anhydride component is first put in a solvent, and then the aromatic diamine component is added so as to be equivalent to the aromatic acid anhydride component for polymerization.
(3) After one aromatic diamine component is put in a solvent, after mixing for a time required for the reaction at a ratio of 95 to 105 mol% of one aromatic acid anhydride component with respect to the reaction component, A method in which one aromatic diamine component is added, and then the other aromatic acid anhydride component is added and polymerized so that the total aromatic diamine component and the total aromatic acid anhydride component are approximately equivalent,
(4) After one aromatic acid anhydride component is placed in a solvent, after mixing for one reaction time at a ratio of 95 to 105 mol% of one aromatic diamine component with respect to the reaction component, A method in which one aromatic acid anhydride component is added, and then the other aromatic diamine component is added and polymerized so that the wholly aromatic diamine component and the wholly aromatic acid anhydride component are approximately equivalent,
(5) A polyamic acid solution (A) is prepared by reacting one aromatic diamine component and an aromatic acid anhydride component in a solvent so that either one becomes excessive, and the other aromatic diamine component in another solvent. The polyamic acid solution (B) is prepared by reacting either the diamine component or the aromatic acid anhydride component so as to be excessive. A method in which the polyamic acid solutions (A) and (B) thus obtained are mixed to complete the polymerization. At this time, when adjusting the polyamic acid solution (A), if the aromatic diamine component is excessive, the polyamic acid solution (B) has excessive aromatic acid anhydride component, and the polyamic acid solution (A) has aromatic acid anhydride. When the component is excessive, in the polyamic acid solution (B), the aromatic diamine component is excessive, and the polyamic acid solutions (A) and (B) are mixed and the wholly aromatic diamine component and wholly aromatic used in these reactions. The method of adjusting so that an acid anhydride component may become substantially equivalent, etc. are mentioned.
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 at a ratio in which the respective mole numbers are approximately equal, and one of them is 10 mol%, preferably 5 mol%. You may mix | blend excessively with respect to the other within the range.

  The polymerization reaction is preferably performed with 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 of 0 to 80 ° C. The polymerization time is not particularly limited, but it is preferably performed continuously for 10 minutes to 30 hours. In the polymerization reaction, the polymerization reaction may be divided or the temperature may be increased or decreased as necessary. Although there is no restriction | limiting in particular in the addition order of both reactants, It is preferable to add an aromatic acid anhydride in the solution of an aromatic diamine component. Vacuum degassing during the polymerization reaction is an effective method for producing a high-quality organic solvent solution of polyamic acid. Further, the polymerization reaction may be controlled by adding a small amount of an end-capping agent to the aromatic diamine before the polymerization reaction. The end-capping agent is not particularly limited, and a known one can be used.

  The polyamic acid solution thus obtained contains a solid content of usually 5 to 40% by weight, preferably 10 to 30% by weight. The viscosity is a value measured by a Brookfield viscometer and is not particularly limited, but is usually 10 to 2000 Pa · s (100 to 20000 poise), and preferably 100 to 1000 Pa · s for stable liquid feeding. (1000-10000 poise). In addition, the polyamic acid in the organic solvent solution may be partially imidized.

A polyimide film can be produced by heating the polyamic acid solution.
As a method for producing a polyimide film, for example, a method in which a polyamic acid solution is cast into a film and thermally decyclized and desolvated to obtain a polyimide film, a cyclization catalyst and a dehydrating agent are mixed in the polyamic acid solution, and a chemical is obtained. A method of obtaining a polyimide film by preparing a gel film by decyclizing it and heating and desolvating it is preferred, but the latter is preferred.

  In the method of chemically decyclizing, first, the polyamic acid solution is prepared. The polyamic acid solution can contain a cyclization catalyst (imidization catalyst), a dehydrating agent, a gelation retarder, and the like.

  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 β-picoline. These may be used alone or in combination of two or more. Among these, an embodiment in which at least one heterocyclic tertiary amine is used is preferable.

  Specific examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. Among them, acetic anhydride and / or Benzoic anhydride is preferred.

  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 cast on a support from a base with a slit and formed into a film shape. There is a method of obtaining a polyimide film by partly proceeding imidization to obtain a gel film having self-supporting property, and then performing heat treatment after peeling from the support.

  The polyamic acid solution is cast on a heated support, undergoes a ring-closing reaction on the support, and becomes a gel film having self-supporting properties and is peeled off from the support.

  The support is a metal rotating drum or an endless belt, and its temperature is controlled by radiant heat from a liquid or gaseous heat medium and / or an electric heater.

  The gel film is usually heated to 30 to 200 ° C., preferably 40 to 150 ° C. by receiving heat from the support and / or receiving heat from a heat source such as hot air or an electric heater. It becomes self-supporting by drying the volatile matter of and is peeled from the support.

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

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

  Moreover, the thickness of a polyimide film can be adjusted with a running speed. What is necessary is just to select the thickness of a polyimide film suitably according to the thickness of the target laminated | multilayer film, the number of sheets of the polyimide film to be used, etc.

  It is preferable to further anneal the polyimide film thus obtained. By annealing, the thermal shrinkage rate can be easily reduced efficiently (specifically, for example, the thermal shrinkage rate after heating at 200 ° C. for 60 minutes can be 0.2% or less). The method of annealing treatment is not particularly limited, and may be according to a conventional method. Although it does not specifically limit as temperature of annealing treatment, 200-500 degreeC is preferable, 200-370 degreeC is more preferable, 210-350 degreeC is especially preferable. Specifically, it is preferable to carry out the annealing treatment by running the film in a furnace heated to the above temperature range under low tension. The time during which the film stays in the furnace is the processing time, but it is controlled by changing the running speed, and the processing time is preferably 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 (for example, inorganic particles, organic filler, etc.), and preferably contains inorganic particles.
Although content of the filler in a polyimide film is not specifically limited, For example, it may be 0.03-1 weight%, Preferably it may be about 0.05-0.8 weight%.

  Although the method of making a polyimide film contain a filler is not specifically limited, You may add a filler to an above described polyamic acid solution. The filler may be added to a previously 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 ° C. for 60 minutes is not particularly limited, but is, for example, 0.2% or less (for example, 0.01 to 0.15%), preferably 0.15% or less ( For example, it may be 0.01 to 0.1%), more preferably 0.1% or less (for example, 0.01 to 0.07%). By using such a polyimide film, it is easy to efficiently reduce the thermal shrinkage rate in the polyimide film with an adhesive.
The heat shrinkage rate after heating the polyimide film at 200 ° C. for 60 minutes is the CNC image processing system NEXIV VM- after the film size (L1) after being left in a room adjusted to 25 ° C. and 60% RH for 2 hours or more. The film dimensions (L2) after measurement using a 250 (Nikon), followed by heating at 200 ° C. for 60 minutes and then leaving again in a room adjusted to 25 ° C. and 60% RH for one day are measured with the CNC image. It can be measured using a processing apparatus system and calculated by the following formula.
Thermal contraction rate (%) = − {(L2−L1) / L1} × 100

  Although the average linear expansion coefficient of a polyimide film is not specifically limited, For example, 0-100 ppm / degrees C, Preferably it is 0-50 ppm / degrees C, More preferably, 3-35 ppm / degrees C may be sufficient. The thermal expansion coefficient can be measured using TMA-50 manufactured by Shimadzu Corporation under the conditions of a measurement temperature range: 50 to 200 ° C. and a temperature increase rate: 10 ° C./min.

The surface roughness Rmax of the polyimide film is preferably 0.6 μm or more (for example, 0.6 to 0.6 μm or more from the viewpoint of improving the adhesiveness between the adhesive layer and the reinforcing plate bonded to the surface opposite to the adhesive layer). 2 μm). Further, the surface roughness Rz of the polyimide film is preferably about 0.3 μm or more (for example, 0.3 to 1.2 μm) from the viewpoint of improving the adhesiveness with the adhesive layer. The measurement of the surface roughness of the polyimide film may be in accordance with JIS B 0601 (2001).
A method for obtaining a polyimide film having such a surface roughness is not particularly limited. For example, it can be obtained by a known surface treatment (for example, wet blast treatment, sand mat treatment, resin mat treatment, plasma treatment, etc.). it can. The surface treatment may be performed on one side or both sides of the polyimide film.

  In addition, in the polyimide film with an adhesive, the polyimide film may be a substantially non-halogen-based polyimide film (a polyimide film not containing a halogen). A polyimide film containing no flame retardant aid may be used.

[Adhesive layer]
The adhesive is not particularly limited as long as it can form an adhesive layer, but usually contains an adhesive component.
Examples of the adhesive component include thermoplastic resins (for example, polyamide resins), thermosetting resins (for example, unsaturated polyester resins, epoxy resins), and the like, and thermosetting resins are preferable.

The adhesive layer may contain an additive as long as the adhesiveness is not impaired. As the additive, for example, a flame retardant (or a flame retardant aid), an antioxidant, a crosslinking agent, a resin not included in the category of an adhesive component (hereinafter also simply referred to as “other resin”). For example, an elastomer (for example, a styrene-based elastomer)} or the like can be given.
In particular, the adhesive layer may contain a flame retardant (including a flame retardant aid), but may not substantially contain a flame retardant. In the present invention, excellent flame retardancy can be exhibited even if the adhesive layer does not substantially contain a flame retardant.

  Flame retardants (including flame retardant aids) include general-purpose components such as metal hydrates [for example, metal hydroxides (eg, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, barium hydroxide, etc.) , Tin oxide hydrate, basic magnesium carbonate, etc.], halogen compounds {eg, halogen-containing low molecular weight compounds (decabromodiphenyl ether, halogenated bisphenol A, etc.), halogen-containing resins [eg, epoxy resins (brominated epoxy resins) Etc.], etc.], antimony compounds (eg, antimony trioxide, etc.), phosphorus compounds (eg, phosphorus-containing oligomers, ammonium phosphate, aluminum trisdiphenylphosphinate), and the like.

  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, for example, 1.5 to 200 parts by weight (for example, 2 to 170 parts by weight), preferably 2 to 1 part by weight of the adhesive component. It may be about 150 parts by weight (for example, 3 to 140 parts by weight), more preferably about 3 to 120 parts by weight (for example, 5 to 100 parts by weight).

  In particular, for the flame retardant, even if the adhesive layer contains a flame retardant, it is preferably at a level that does not substantially contain the flame retardant, and the ratio of the flame retardant is, for example, a component of the adhesive layer (solid content ) 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 3% by weight or less based on the whole.

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

[Polyimide film with adhesive]
In the polyimide film with an adhesive, 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 (for example, 7 to 100 μm), and more preferably 10 to 80 μm. (For example, about 15-50 micrometers) may be sufficient.

  In the polyimide film with an adhesive, the thickness (average thickness) of the adhesive layer is not particularly limited, but is, for example, 300 μm or less (for example, 1 to 250 μm), preferably 200 μm or less (for example, 2 to 180 μm), It may be preferably 150 μm or less (for example, 3 to 120 μm), particularly 100 μm or less (for example, 5 to 80 μm), and usually 1 to 50 μm (for example, 3 to 40 μm, preferably 5 to 35 μm, more preferably 10 to 10 μm). 30 μm).

  In particular, the thickness of the adhesive layer (average thickness) is preferably not too large relative to the total thickness of the polyimide film with adhesive, for example, a polyimide film (a polyimide film without an adhesive layer) ) Thickness (average thickness) of 3 times or less (for example, 0.01 to 2.8 times), for example, 2.5 times or less (for example, 0.05 to 2. 4 times), preferably 2.3 times or less (for example, 0.1 to 2.2 times), more preferably 2 times or less (for example, 0.15 to 1.8 times), particularly 1.5 times or less ( For example, it may be 0.2 to 1.2 times), and may be usually 0.25 to 2.3 times.

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

  Further, the thickness (average thickness) of the adhesive layer may be 1/2 or more of the thickness of the conductor in consideration of the embedding property of the conductor. In this case, it is preferable from the viewpoint of sufficient embedding of the conductors and less likelihood of voids between the conductors.

The polyimide film with an adhesive of the present invention is excellent in flame retardancy.
For example, the oxygen index of the polyimide film with an adhesive 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, 32 to 80%), preferably 35%. It may be more (for example, 37 to 75%), more preferably 40% or more (for example, 42 to 70%), particularly 45% or more (for example, 46 to 65%).

  In addition, an oxygen index can be measured based on JISK7201-2, for example.

  The adhesive layer of the polyimide film with an adhesive may adjust the penetration amount with needles in the TMA needle mode measurement to a specific range.

  For example, the adhesive layer of the polyimide film with adhesive has a needle penetration amount (penetration ratio) at 100 ° C. of 10% or less (for example, 0 to 8%) with respect to the thickness of the adhesive layer in the TMA needle penetration mode measurement. ), Preferably 7% or less (for example, 0.1 to 6%), more preferably 6% or less (for example, 0.3 to 5.5%), particularly 5% or less (for example, 0.5 to 5%) ) May be satisfied.

  In addition, the penetration amount (penetration ratio) into the needle with respect to the thickness of the adhesive layer is (B / A) × 100 (%) when the thickness of the adhesive layer is A (μm) and the penetration amount into the needle is B (μm). ).

  Further, the adhesive layer of the polyimide film with adhesive has a needle penetration amount (penetration ratio) at 140 ° C. of 5% or more (for example, 7 to 90%) with respect to the thickness of the adhesive layer in the TMA needle penetration mode measurement. 10% or more (for example, 15 to 88%), preferably 20% or more (for example, 20 to 85%), more preferably 25% or more (for example, 26 to 80%). You may be satisfied.

  The adhesive layer of the polyimide film with the adhesive has a penetration amount (penetration rate) of the needle at 180 ° C. of 20% or more (for example, 22 to 95%) with respect to the thickness of the adhesive layer in the TMA needle entering mode measurement. The range can be selected, for example, 25% or more (for example, 27 to 92%), preferably 30% or more (for example, 35 to 90%), more preferably 40% or more (for example, 42 to 88%), particularly 45 % Or more (for example, 50 to 85%) may be satisfied.

  By adjusting the penetration with a needle at each temperature as described above, it is easy to efficiently adjust flame retardancy, heat resistance, dimensional stability, the amount of bubbles generated between conductors, and the like.

  In addition, the penetration amount into the needle at each temperature (100 ° C., 140 ° C., 180 ° C.) of the TMA needle entering mode measurement is measured up to 200 ° C. at a temperature rising rate of 10 ° C./min using a TMA measuring device. The indenter penetration depth (penetration amount, unit: μm) is read up to each temperature (100 ° C., 140 ° C., 180 ° C.), and each temperature with respect to the thickness of the adhesive layer (100 ° C., 140 ° C., 180 ° C.) Can be determined by the ratio of the penetration depth of the indenter. As the TMA measuring device, a thermal analyzer (TMA-60) manufactured by Shimadzu Corporation may be used.

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

[Flat cable]
Especially the polyimide film with an adhesive agent of this invention can be used for manufacture of a flat cable.
The method for producing the flat cable is not particularly limited as long as it is a method of sandwiching (clamping) the conductor between two (a pair of) adhesive-attached polyimide films. In a flat cable, a conductor is usually sandwiched between adhesive layers of a polyimide film with an adhesive. A flat cable can be manufactured by, for example, sandwiching a conductor row in which a plurality of conductors are arranged in the same plane between adhesive layers of a polyimide film with an adhesive. In addition, you may perform a heating, pressurization, etc., when a conductor is inserted | pinched between the polyimide films with an adhesive agent.

  Although it does not specifically limit as a conductor, For example, the flat metal foil of a conductive metal, a round wire, a flat conductor with a rectangular cross section, an organic conductor, etc. are mentioned. Although it does not specifically limit as a conductive metal, You may use copper, silver, tin, an indium, aluminum, molybdenum, these alloys, etc. Further, the width and thickness of the conductor are not particularly limited.

The flat cable may further have a reinforcing plate.
The reinforcing plate is, for example, a polyimide film alone or a laminate of a plurality of polyimide films (for example, 2 to 3 sheets). Although there is no designation for a method of laminating a plurality of polyimide films, there are a method of laminating only a polyimide film, a method of laminating other layers (for example, an adhesive layer) between polyimide films, and the like. The structure 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 μm (for example, 75 to 300 μm).
Moreover, the reinforcing plate may be laminated | stacked on the single side | surface of the flat cable, and may be laminated | stacked on both surfaces.

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

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples at all, and many variations are within the technical idea of the present invention. This is possible by those with ordinary knowledge.

[Polyamic acid synthesis example A]
Pyromellitic dianhydride (molecular weight 218.12) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) was prepared at a molar ratio of 1: 1, and 20 in DMAc (N, N-dimethylacetamide). Polymerization was performed in a weight% solution to obtain a 4000 poise polyamic acid solution.

[Polyamic acid synthesis example B]
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) is prepared in a molar ratio of 60/40/80/20, polymerized in a 20 wt% solution in DMAc (N, N-dimethylacetamide), and polymerized to 4000 poise An acid solution was obtained.

[Oxygen index measurement]
It measured based on JISK7201-2. The polyimide film with an adhesive was cut into a size of 150 mm × 20 mm and burned using an oxygen index method flammability tester manufactured by Suga Test Instruments Co., Ltd.

[Thermal shrinkage of polyimide film]
The heat shrinkage rate after heating the polyimide film at 200 ° C. for 60 minutes is the CNC image processing system NEXIV VM- after the film size (L1) after being left in a room adjusted to 25 ° C. and 60% RH for 2 hours or more. The film dimensions (L2) after measurement using a 250 (Nikon), followed by heating at 200 ° C. for 60 minutes and then leaving again in a room adjusted to 25 ° C. and 60% RH for one day are measured with the CNC image. It measured using the processing apparatus system, and computed by the following formula.
Thermal contraction rate (%) = − {(L2−L1) / L1} × 100

[Surface roughness of polyimide film]
The surface roughness of the polyimide film was measured according to JIS B 0601 (2001). Surface roughness Rmax and Rz were measured under the following conditions using a contact-type surface roughness measuring instrument.
Cut-off value: 0.25 mm, measurement length: 2 mm, stylus tip half radius: 2 μm

[Intrusion rate with needle]
A polyimide film with an adhesive is cut into a size of 10 mm × 10 mm, and a constant load of 50 gf is applied up to 200 ° C. at a heating rate of 10 ° C./min using a Shimadzu thermal analyzer (TMA-60). The indenter penetration depth (penetration amount, unit: μm) was read up to 100 ° C., 140 ° C., and 180 ° C. And the ratio with respect to the thickness of an adhesive bond layer was computed from the read numerical value.
The indenter used was a cylindrical shape with a tip diameter of 0.5 mm, and the surface of the adhesive was the indenter entry surface.

[Embeddability]
The presence or absence of air bubbles between the flat cable conductors was visually confirmed, and the length of the location where air bubbles were generated was measured. The ratio of the length of the bubble generation location to the length of the flat cable was calculated and used as the bubble generation rate.

[Heat shrinkage of flat cable (dimensional change rate)]
The produced flat cable is heated at 180 ° C. for 10 minutes, and the inter-conductor dimension (L3) before heating and the inter-conductor dimension (L4) after heating are measured using a CNC image processing system NEXIV VM-250 (made by Nikon). Measured and calculated according to the following formula.
Thermal contraction rate (%) =-{(L4-L3) / L3} × 100

[Film formation of polyimide film A]
The total particle size of the inorganic particles is 0.01 μm or more and 6.0 μm or less, and the average particle size is 0.87 μm, and the particle size is 0.5 to 2.5 μm. N, N-dimethylacetamide slurry of calcium oxyhydrogen was added to the polyamic acid solution obtained in Synthesis Example A by 0.15% by weight per resin weight, and sufficiently stirred and dispersed. The polyamic acid solution was mixed and stirred with a conversion agent composed of acetic anhydride (molecular weight 102.09) and β-picoline at a ratio of 2.0 molar equivalents with respect to the polyamic acid. The obtained mixture was cast from a die onto a rotating 65 ° C. stainless steel drum to obtain a gel film having self-supporting properties. The gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 250 ° C. for 30 seconds, 400 ° C. for 30 seconds, and then 550 ° C. for 30 seconds. The obtained film was annealed in a heating furnace at 300 ° C. for 1 minute to obtain a polyimide film having a thickness of 25 μm, Rmax 0.8 μm, and Rz 0.5 μm.

[Film formation of polyimide film B]
One surface of the polyimide film A was sand-matted to obtain a polyimide film B having a thickness of 25 μm, a sand mat-treated surface of Rmax 1.4 μm, and Rz 1.0 μm. The sand mat treatment was performed by hitting particles having a sand particle size distribution with a sand diameter of 80 to 200 μm on the film surface.

[Film formation of polyimide film C]
In forming the polyimide film A, a polyimide film C was prepared in the same manner 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 μm, Rmax was 0.8 μm, and Rz was 0.5 μm.

Example 1
[adhesive]
EPICLON HP-7200 (manufactured by DIC Corporation, dicyclopentadiene skeleton-containing epoxy resin) 10 parts by weight, Tuftec M1913 (Asahi Kasei Chemicals Corporation, maleic acid-modified styrene ethylene block copolymer) 100 parts by weight, Curesol C11-Z (Shikoku) 0.3 parts by weight (made by Kasei Co., Ltd.) and 420 parts by weight of toluene were mixed to prepare an adhesive.

[Polyimide film with adhesive]
The said adhesive agent was apply | coated to the single side | surface of the polyimide film A obtained above, and it was made to dry at 90 degreeC for 3 minutes, and the polyimide film with an adhesive agent was obtained. In the polyimide film with an adhesive, the thickness of the adhesive layer was 25 μm.

[Flat cable sample preparation]
51 conductors with a width of 0.30 mm and a thickness of 0.035 mm are arranged on the adhesive layer side of the polyimide film with adhesive at a pitch of 0.50 mm between the conductors, and another polyimide with adhesive is further formed thereon. A flat cable was prepared by pressing the adhesive layer side of the film on top of each other and pressing with a hot roll at 180 ° C. and 0.5 MPa.

Example 2
A flat cable was produced in the same manner as in Example 1 except that polyimide film B was used instead of polyimide film A, and an adhesive was applied to the sand mat-treated surface of polyimide film B.

Example 3
In the adhesive, jER828 (Mitsubishi Chemical Corporation, bisphenol A type epoxy resin) is used instead of EPICLON HP-7200, and TD773 (DIC Corporation, novolak type phenol resin) is used instead of Tuftec M1913. A flat cable was produced in the same manner as in Example 1 except that the thickness of the adhesive layer was 20 μm.

Example 4
In the adhesive, YDCN-700-3 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., cresol novolac epoxy resin) was used instead of EPICLON HP-7200, and Nipol 1072J (manufactured by Nippon Zeon Co., Ltd., carboxyl group-containing acrylonitrile) instead of Tuftec M1913 A flat cable was produced in the same manner as in Example 1 except that the thickness of the polyimide film was adjusted to 12.5 μm.

Example 5
A flat cable was produced in the same manner as in Example 1 except that the drying condition for applying and drying the adhesive on one side of the polyimide film was 130 ° C. for 10 minutes.

Example 6
A polyimide film with an adhesive 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 thickness of the adhesive layer was 60 μm.

  Table 1 shows the physical properties of the polyimide film and flat cable obtained in each example and reference example.

  The polyimide film with adhesive of the example had a large oxygen index of at least 37%. Further, the heat shrinkage rate (dimensional change rate) at 180 ° C. was as small as 0.08% at the maximum. Furthermore, in Examples 1 to 4 and 6, it was possible to reduce the generation of bubbles between conductors.

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

  The polyimide film with an adhesive of the present invention is excellent in flame retardancy and can be suitably used for flat cables and the like.

Claims (9)

  A polyimide film with an adhesive having an oxygen index of 30% or more.   The polyimide film with an adhesive 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 amount of penetration into the adhesive layer at 100 ° C. in the TMA needle entering mode measurement is 10% or less of the thickness of the adhesive layer, and / or the penetration into the needle layer at 140 ° C. in the TMA needle entering mode measurement of the adhesive layer. The polyimide film with an adhesive according to claim 1 or 2, wherein the amount is 20% or more of the thickness of the adhesive layer.   The polyimide film with an adhesive according to any one of claims 1 to 3, wherein an amount of penetration with a needle at 180 ° C in a TMA needle entry mode measurement of the adhesive layer is 40% or more of the thickness of the adhesive layer.   The polyimide film is one or more aromatic diamine components selected from the group consisting of paraphenylenediamine, 4,4′-diaminodiphenyl ether and 3,4′-diaminodiphenyl ether, pyromellitic dianhydride and / or 3,3. The polyimide film with an adhesive according to any one of claims 1 to 4, comprising an aromatic acid anhydride component of ', 4,4'-biphenyltetracarboxylic dianhydride as a raw material.   The polyimide film with an adhesive in any one of Claims 1-5 in which an adhesive bond layer contains the adhesive component containing an epoxy resin, and the additive containing other resin.   The adhesive-attached polyimide film according to claim 1, wherein the adhesive layer does not substantially contain a flame retardant.   The polyimide film with an adhesive according to any one of claims 1 to 7, which is used for producing a flat cable.   The flat cable which pinched | interposed the conductor with the polyimide film with an adhesive in any one of a pair of Claims 1-8.