KR20180036601A - Polyimide film - Google Patents

Abstract

Provided is a polyimide film with low nonuniformity in dimensional change. To this end, in the polyimide film, a coefficient of linear expansion (αMD) of the film a machine direction (MD) and a coefficient of linear expansion (αTD) in a width direction (TD) are all set to 7 ppm/°C or less, and an anisotropy index (AI) value over the whole width represented by an equation below (in the case of measuring the propagation velocity (V) of the ultrasonic pulses) is set to be 15 or less, wherein the equation is represented by AI = (VMAX^2-VMIN^2) / (VMAX^2+VMIN^2). In the equation, VMAX^2 is the square of the maximum value of the pulse propagation velocity, and VMIN^2 is the square of the minimum value of the pulse propagation velocity.

Description

Polyimide film [0002]

The present invention relates to a polyimide film and a manufacturing method thereof. Further, the present invention relates to a flexible metal laminate including the polyimide film and the metal foil.

[0003] Flexible printed circuits (FPCs) are generally formed by a variety of insulating materials, and flexible insulating insulating films are used as a substrate, and a metal foil is heated and pressed on the surface of the substrate, . As the insulating film, a polyimide film having excellent heat resistance and electrical insulation is preferably used.

In recent years, in order to achieve miniaturization and weight reduction of electronic devices, the wiring provided on the substrate is becoming finer, and the parts to be mounted are also miniaturized and densified. Therefore, if the dimensional change after the fine wiring is formed becomes large, there arises a problem that the component and the substrate are not properly connected to each other, deviating from the component mounting position in the designing stage.

Attempts have been made to reduce the dimensional change of such a polyimide film. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2015-10107) discloses a film having a film thickness of 1 m or more and a film orientation angle? Of 45 degrees and 135 degrees The values of the orientation coefficients AI (45, 135) in the diagonal lines (45, 135) were 12 or less over the entire width, and the dimensional change rates before and after the etching treatment of the flexible metal laminate plates in the diagonal To 0.05% by weight, and the dimensional change is reduced by a polyimide film having a thermoplastic polyimide layer having a thickness of 0.5 to 20 占 퐉 on at least one side.

Thus, improvement of a new polyimide film is required.

Patent Document 1: JP-A-2015-10107

It is an object of the present invention to provide a polyimide film having a small variation in dimensional change in the film thickness direction and a flexible metal laminate including the polyimide film.

Another object of the present invention is to provide a polyimide film having a small elongation after heat treatment and a flexible metal laminate including the polyimide film.

It is still another object of the present invention to provide a method for producing a polyimide film having the above properties with good film-forming properties.

According to the investigations of the present inventors, it has been found that the film of the Patent Document 1 improves the dimensional change to some extent, but the film has unevenness in dimensional change as a whole or causes a flat elongation phenomenon due to heat treatment. In addition, although it has been studied to adjust the imidization on the support so as to make both of the reduction in the dimensional change unevenness and the reduction in the elongation at break possible, it has been difficult to achieve compatibility between the film and the film due to tearing .

Among these, the inventors of the present invention have found that, in the polyimide film, as in Patent Document 1, the present inventors have found that not only a specific angle but also the orientation of all angles are defined as a specific AI value, It has been found that the combination of the coefficient of linear expansion can not only reduce the dimensional change but also suppress the unevenness and further reduce the elongation after heat treatment. In order to adjust the coefficient of linear expansion, it has been found that it is necessary to adjust the imidization rate and the like of a gel film which is a precursor film of a polyimide film. Based on this finding, further research has been conducted and the present invention has been completed.

That is, the present invention relates to the following inventions:

[1] An anisotropy index AI expressed by the following equation when the propagation velocity V of the ultrasonic pulse is measured and both the coefficient of linear expansion? MD of the film in the machine direction MD and the coefficient of linear expansion? TD in the width direction TD are 7 ppm / Wherein the value is 15 or less over the entire width.

AI = (VMAX ^ 2-VMIN ^ 2) / (VMAX ^ 2 + VMIN ^ 2)

(Where VMAX ^ 2 is the square of the maximum pulse propagation velocity and VMIN ^ 2 is the square of the pulse propagation velocity minimum).

[2] The polyimide film according to [1], wherein the film-forming width is 1000 mm or more and the difference (difference between the maximum value and the minimum value) of the linear expansion coefficient in the film width direction of? MD is 2 ppm / 占 폚 or less.

[3] A polyimide film according to [1] or [2], wherein the film-forming width is 1000 mm or more and the difference (difference between the maximum value and the minimum value) of the coefficient of linear expansion in the film width direction of? TD is 2 ppm /

[4] The polyimide film according to any one of [1] to [4], wherein the polyimide film is at least one selected from the group consisting of an aromatic diamine component containing paraphenylenediamine, pyromellitic dianhydride and 3,3'-4,4'-diphenyltetracarboxylic acid dianhydride The polyimide film according to any one of [1] to [3], wherein the polyimide film comprises a polyimide having an acid anhydride component as a polymerization component.

[5] A method for producing a polyimide precursor solution by applying a polyimide precursor solution on a support to prepare a gel film (in particular, a gel film having partially self-supporting properties by drying and curing) A method for producing a polyimide film according to any one of [1] to [4], wherein heat treatment (drying and heat treatment) is performed while passing both ends in a direction while passing through a heating furnace.

[6] The production method according to [5], wherein the imidization rate of the gel film (gel film peeled from the support) is 55 to 75%.

[7] A flexible metal laminate comprising the polyimide film described in any one of [1] to [4] and a metal foil.

The polyimide film of the present invention is less uneven in dimensional change in the film-film width direction. Further, the polyimide film of the present invention has a small shear elongation after heat treatment. In the flexible metal laminate obtained by using the polyimide film of the present invention, the dimensional change before and after the removal of the metal foil is small in the width direction of the polyimide film.

Therefore, it can be suitably used for a flexible metal laminate (FPC) in which fine wiring is formed.

Further, according to the production method of the present invention, a polyimide film having excellent properties as described above can be produced with excellent film-forming properties by adjusting the imidization rate of the gel film.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

[Polyimide film]

The polyimide film of the present invention has a specific linear expansion coefficient and anisotropy index (AI value). By having such a combination of the specific linear expansion coefficient and the specific AI value, it is possible to efficiently produce a film with less nonuniformity in dimensional change and little afterglow elongation.

The coefficient of linear expansion and the AI value are determined by, for example, the composition of the polyimide constituting the film, the production conditions of the film (the imidization rate of the gel film, the stretching condition, the temperature of the support, the imidization rate, And so on.

First, in the polyimide film of the present invention, both the linear expansion coefficient? MD of the film in the machine direction (MD) and the linear expansion coefficient? TD in the width direction (TD) are 7 ppm / ° C or less, preferably 6 ppm / / RTI > or less, especially 4.5 ppm / C or less.

In the polyimide film of the present invention, the difference in coefficient of linear expansion in the film width direction of? MD is, for example, 3 ppm / ° C or less, preferably 2 ppm or less, more preferably 1.5 ppm or less.

In the polyimide film of the present invention, the difference in coefficient of linear expansion in the film width direction of? TD may be, for example, 3 ppm / ° C or less, preferably 2 ppm / ° C or less, more preferably 1.5 ppm or less.

The coefficient of linear expansion can be measured using, for example, TMA-50 (manufactured by Shimadzu Corporation) under the conditions of a measurement temperature range of 50 to 200 DEG C and a temperature increase rate of 10 DEG C / min.

The coefficient of linear expansion is, for example, two points selected 200 mm inward from the both ends of the film width in the film width direction, and within a range of a straight line connecting the two points, And the other arbitrary two points are selected and the coefficient of linear expansion is measured at least at these five points and obtained as an average value of the obtained measurement values.

The difference (unevenness) in the coefficient of linear expansion in the film width direction can be obtained by, for example, selecting two points that are 200 mm inward from both ends of the film forming width in the film width direction, One point within the central portion of 200 mm on the straight line including two points and another arbitrary two points are selected and the linear expansion coefficient is measured at least at these five points to obtain the difference between the maximum value and the minimum value among the obtained measurement values.

In the polyimide film of the present invention, the anisotropy index AI value expressed by the following formula when the propagation speed V of the ultrasonic pulse is measured is 15 or less (for example, 0 to 15 (for example, (For example, 1 to 14.2), more preferably 14 or less (for example, 2 to 13.8), particularly 13.5 or less (for example, 3 to 13.2)) .

AI = (VMAX ^ 2-VMIN ^ 2) / (VMAX ^ 2 + VMIN ^ 2)

(Where VMAX ^ 2 is the square of the maximum pulse propagation velocity and VMIN ^ 2 is the square of the pulse propagation velocity minimum).

The AI value can be measured, for example, in the following manner: two points that are 200 mm inward from both ends of the film forming width in the film width direction are selected, and within the range of the straight line connecting the two points One point within the center of the straight line including the two points within 200 mm and another arbitrary two points are selected and AI is measured at least at these five points. AI can be measured using SOM-2500 manufactured by Nomura. With the SST-2500, ultrasonic velocities in 16 directions are automatically measured every 11.25 ° with respect to the film plane direction 0 to 180 ° (0 ° parallel to MD). The angle (orientation angle) means the direction of the orientation axis, and the machine direction MD of the film is set to 0 deg., Which is a reference line, and is expressed by an angle on the side rotated clockwise. The largest pulse propagation velocity among the obtained velocities in each direction is VMAX, and the smallest pulse propagation velocity among the obtained velocities in each direction is VMIN. From these values, AI is obtained.

The width (film-forming width) of the polyimide film of the present invention is not particularly limited, but is preferably 1000 mm or more (for example, 1200 to 2500 mm), more preferably 1500 mm or more (for example, 1700 to 2500 mm ), More preferably not less than 2000 mm (for example, 2000 to 2500 mm).

In the present invention, even with such a relatively wide film, it is possible to satisfy the above-mentioned specific linear expansion coefficient and anisotropy index (AI value), and it is possible to reduce nonuniformity in dimensional change (heat shrinkage) and short elongation after heat treatment.

The thickness (average thickness) of the polyimide film of the present invention is not particularly limited and may be appropriately selected depending on the application, and may be, for example, 1 탆 or more (for example, 1 to 300 탆) And more preferably 3 to 150 占 퐉 (for example, 5 to 100 占 퐉).

As described above, the polyimide film of the present invention has a small dimensional change (heat shrinkage) in the film thickness direction and a small uneven elongation after heat treatment. In addition, the flexible metal laminate obtained by using the polyimide film of the present invention has a small dimensional change rate non-uniformity in the film-coating width direction.

For example, the polyimide film of the present invention may be 0.05% or less, preferably 0.04% or less, in the variation of the dimensional change ratio in the film film width direction before and after removing the metal foil of the flexible metal laminate plate.

In the polyimide film of the present invention, the heat shrinkage difference at 200 占 폚 in the width direction may be 0.05% or less, preferably 0.04% or less, more preferably 0.02% or less.

The non-uniformity of the rate of dimensional change and the difference in heat shrinkage in the film width direction can be measured by, for example, selecting two points that are 200 mm inward from both ends of the film width in the film width direction, A point within a range of ± 200 mm on the straight line including the two points and other arbitrary two points are selected and the dimensional change rate and the heat shrinkage ratio are measured by at least these five points and the maximum and minimum values Can be obtained as a difference.

Further, the polyimide film of the present invention has a width of 508 mm and a length of 6.5 m, and has a half-elongation (length of a in Fig. 1 described later) when treated at 200 캜 for 30 minutes, May be 4 mm or less, more preferably 3.5 mm or less.

The film of the present invention is composed (or formed) of polyimide. Hereinafter, the polyimide will be described together with the film production method.

[Production method of polyimide and polyimide film]

The polyimide (or polyamic acid) contains an aromatic diamine component and an acid anhydride component as polymerization components.

Specifically, when producing a polyimide (or polyimide film), first, a polyamic acid (polyimide precursor) solution is obtained by polymerizing an aromatic diamine component and an acid anhydride component in an organic solvent.

The aromatic diamine component usually contains at least paraphenylenediamine (PPD). The aromatic diamine component may include a compound other than para-phenylenediamine, and specific examples of the aromatic diamine component other than paraphenylenediamine include metaphenylenediamine, benzidine, para-xylylenediamine, 4,4'-di Aminodiphenyl 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-aminophenyl) benzene and amide-forming derivatives thereof.

These may be used alone or in combination of two or more.

The aromatic diamine component is preferably a combination of paraphenylenediamine (PPD), 4,4'-diaminodiphenyl ether and / or 3,4'-diaminodiphenyl ether (DPE) (PPD), 4,4'-diaminodiphenyl ether and / or 3, 4'-diaminodiphenyl ether (DPE) are preferable, and paraphenylenediamine (PPD) 4,4'-diaminodiphenyl ether (DPE) is preferred.

When the aromatic diamine component contains p-phenylenediamine, the proportion of p-phenylenediamine to the aromatic diamine component is, for example, 20 mol% or more (for example, 25 to 100 mol%), preferably 30 mol (For example, 31 to 80 mol%), more preferably 35 mol% or more (for example, 37 to 70 mol%), and usually 30 to 50 mol% Mole%).

When PPD / DPE (molar ratio) is combined with paraphenylenediamine (PPD) and / or 4,4'-diaminodiphenyl ether and / or 3,4'- diaminodiphenyl ether (DPE) May be about 80/20 to 30/70, preferably 75/25 to 35/65 (for example, 70/30 to 35/65), and usually about 60/40 to 30/70 (for example, / 50 to 35/65, preferably 45/55 to 37/63).

Examples of the acid anhydride component (or an amide-forming derivative of an acid) include pyromellitic acid, 3,3 ', 4,4'-diphenyltetracarboxylic acid, 2,3', 3,4'- (3, 4-dicarboxyphenyl) ether, pyridine-2, 3, 4, 5-benzophenone tetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, , 5,6-tetracarboxylic acid, and the like. These may be used alone or in combination of two or more. Among these, pyromellitic dianhydride (PMPA) and 3,3 ', 4,4'-diphenyltetracarboxylic dianhydride (BPDA) are preferable, and it is particularly preferable to combine them.

When the acid anhydride component contains BPDA, the ratio of BPDA to the acid anhydride component is, for example, not less than 15 mol% (for example, 15 to 100 mol%), preferably not less than 20 mol% , Preferably 22 to 90 mol%), preferably 25 mol% or more (for example, 28 to 80 mol%) and more preferably 30 mol% or more (for example, 32 to 60 mol% 25 to 45 mol% (for example, 30 to 40 mol%).

In the case of combining pyromellitic dianhydride (PMPA) with 3,3 ', 4,4'-diphenyltetracarboxylic dianhydride (BPDA), these ratios are PMPA / BPDA (molar ratio) = 90 / (For example, 75/25 to 40/60), preferably 70/30 to 50/50 (for example, about 70/30 to 80/80, preferably 85/15 to 30/70 and more preferably 80/20 to 35/65 For example, 70/30 to 55/45, preferably 69/31 to 60/40).

Examples of the organic solvent used for forming the polyamic acid solution include sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide, and organic solvents such as N, N-dimethylformamide, N, N-diethylformamide Acetamide solvents such as amide solvents, N, N-dimethylacetamide and N, N-diethylacetamide, N-methyl-2-pyrrolidone and N-vinyl- Phenol solvents such as phenol solvents, phenol solvents, o-, m-, or phenol solvents such as p-cresol, xylenol, halogenated phenol and catechol, or aprotic polar solvents such as hexamethylphosphoramide and? And it is preferable to use them alone or as a mixture using two or more kinds of them, but also aromatic hydrocarbons such as xylene, toluene and the like can be used.

The polymerization method can be carried out by any known method, and for example,

(1) First, all the aromatic diamine component is added to the solvent, and then the acid anhydride component is added to the total amount of the aromatic diamine component (equivalent) to effect polymerization.

(2) First, the entire amount of the acid anhydride component is added to the solvent, and then the aromatic diamine component is added so as to be equivalent to the acid anhydride component.

(3) After adding some of the aromatic diamine component (a1) to the solvent, the mixture is stirred for a period of time required for the reaction to 95 to 105 mol% of the acid anhydride component (b1) (a2) is added, and then the other part of the acid anhydride component (b2) is added in such a manner that the wholly aromatic diamine component and the total anhydride component are almost equivalent.

(4) After adding some acid anhydride component (b1) into the solvent, the reaction mixture is mixed with the reaction component in such a ratio that some of the aromatic diamine component (a1) becomes 95 to 105 mol% (b2), and then adding the other aromatic diamine component (a2) so that the wholly aromatic diamine component and the total anhydride component are substantially equivalent.

(5) reacting the aromatic diamine component and the acid anhydride component in the solvent so that one of the aromatic diamine component and the acid anhydride component is excessive to adjust the polyamic acid solution (A), and the other aromatic diamine component and the acid anhydride component The polyamic acid solution (B) is adjusted. The polyamic acid solutions (A) and (B) thus obtained are mixed to complete the polymerization. When the aromatic diamine component is excessive at the time of adjusting the polyamic acid solution (A), the acid anhydride component is excessively used in the polyamic acid solution (B), or when the acid anhydride component is excessive in the polyamic acid solution (A) In the polyamic acid solution (B), the aromatic diamine component is excessively mixed, and the polyamic acid solution (A) and the polyamic acid solution (B) are mixed so that the wholly aromatic diamine component and the total anhydride component used in these reactions are adjusted to be approximately equivalent. The polymerization method is not limited to these, and other known methods can be used.

The polyamic acid solution may also contain a chemically inert organic filler such as titanium oxide, fine silica, calcium carbonate, calcium phosphate, calcium hydrogenphosphate, polyimide filler and the like in order to obtain the lubricity of the film. Or an inorganic filler.

The polyamic acid solution usually contains about 5 to 40% by weight of solids, preferably about 10 to 30% by weight of solids. In addition, the viscosity may be about 10 to 2000 Pa · s, as measured by a Brookfield viscometer, and it may be about 100 to 1000 Pa · s, for stable liquefaction. In addition, the polyamic acid in the organic solvent solution may be partially imidized.

Next, a method for producing a polyimide film will be described. The film formation (preparation) of the polyimide film is carried out, for example, by a step (1) of obtaining a gel film by subjecting a polyamic acid solution to a cyclization reaction, a step (2) of heating (and desolvation) the obtained gel film . In addition, drying and imidization proceeds by the heat treatment.

In the step (1), the method for carrying out the cyclization reaction of the polyamic acid solution is not particularly limited, but specifically, (i) a polyamic acid solution is cast into a film form and thermally dehydrated and cyclized to obtain a gel film (Heat cycling method), or (ii) a method in which a gelation film is obtained by mixing a polyamic acid solution with a cyclization catalyst and a dialytic agent (dehydrating agent) to chemically dechromate the gel film to obtain a gel film A ring-closing method), and the latter method is particularly preferable. The polyamic acid solution may contain a gelling retarder or the like. The gelling retarder is not particularly limited, and acetylacetone and the like can be used.

Examples of the cyclization catalyst include amines such as aliphatic tertiary amines (trimethylamine, triethylenediamine, etc.), aromatic tertiary amines (such as dimethylaniline), heterocyclic tertiary amines (such as isoquinoline , Pyridine,? -Picoline, etc.). These may be used alone or in combination of two or more. Of these, heterocyclic tertiary amines such as? -Picoline are preferable.

Examples of the dehydrating agent include acid anhydrides such as aliphatic carboxylic anhydrides (for example, acetic anhydride, propionic anhydride, butyric anhydride, etc.) and aromatic carboxylic acid anhydrides (for example, benzoic anhydride). These may be used alone or in combination of two or more. Of these, acetic anhydride and / or benzoic anhydride are preferable, and acetic anhydride is particularly preferable.

The amount of the cyclization catalyst and the dehydrating agent to be used is not particularly limited and may be, for example, 1 mole or more (for example, 1.5 or less) per mole of the amide group (or carboxyl group) of the polyamic acid (For example, about 2.7 to about 5 moles), more preferably about 2 to about 4 moles (for example, about 2 to about 10 moles), preferably about 2 moles For example, 2.5 to 3.3 moles).

The gel film (gel film having self-supporting property) is usually formed by partially applying a polyamic acid solution (in particular, a polyamic acid solution obtained by mixing a cyclization catalyst and a dialytic agent) onto a support (coating) ).

More specifically, in the gel film, a polyamic acid solution is formed into a film shape by flowing on a support from a slit-attaching inlet, and heated by heat from a support such as hydrothermal, hot air or electric heat sources Subjecting the resultant mixture to a ring-closing reaction, and evaporating a volatile component such as an organic solvent, thereby forming a gel film having self-supporting properties and then peeling off the support.

The support is not particularly limited, and examples thereof include a rotary drum made of metal (e.g., stainless steel), an endless belt, and the like. The temperature of the support is not particularly limited and may be, for example, 30 to 200 占 폚, preferably 40 to 150 占 폚, more preferably 50 to 120 占 폚, particularly 70 to 100 占 폚 (for example, 95 ° C).

Further, the temperature of the support can be controlled by (i) a heating medium of liquid or gas, (ii) radiation heat of an electric heater or the like.

The imidization rate of the gel film (the gel film provided for the heat treatment and the gel film peeled from the support) is, for example, 50 to 80%, preferably 52 to 78%, more preferably 55 to 75% For example, 57 to 73%).

In addition, the imidization ratio is, by using the FT-IR 1375cm ^- indicates by means of the following to obtain, depending on the ratio of the peak height of the ^first and 1500cm ^-1 expression.

Imidization rate (%) = A / B x 100

[Wherein, A is (peak height of 1375cm ^-1 in the measurement target film) / (the peak height of the measurement target film 1500cm ^-1), B is (by peak height of 1375cm ^-1 of the polyimide film that is) / (The peak height of 1500 cm ^-1 of the reference film).

By setting the imidization ratio of the gel film within the above range, it is easy to efficiently obtain the polyimide film of the present invention.

In the step (2), the gel film is heated (and desiccated). Usually, the step (2) may include a step of passing the gel film while grasping the both ends in the width direction (holding) of the gel film through a heating furnace (tenter heating furnace), and performing heat treatment (and drying).

Concretely, the gel film peeled off from the support is not particularly limited, but it can be stretched in the machine direction while regulating the traveling speed by a rotary roll. Stretching in the machine direction can be carried out at a temperature of 140 캜 or lower. The draw ratio MDX thereof is generally 1.05 to 1.9 times, preferably 1.1 to 1.6 times, and more preferably 1.1 to 1.5 times (for example, 1.15 to 1.3 times).

Further, the gel film (in particular, the gel film stretched in the machine direction) is introduced into the tenter device, and both ends in the width direction are held tight by the tenter clip, and can be stretched by the width method while traveling together with the tenter clip.

The stretching in the width direction can be carried out at a temperature of 200 캜 or more. The draw ratio (TDX) may be 1.1 to 1.5 times, for example, 1.2 to 1.45 times the MDX. The specific draw ratio (TDX) may be, for example, 1.1 to 2 times, preferably 1.3 to 1.8 times, more preferably 1.35 to 1.7 times (for example, 1.4 to 1.6 times).

The polyimide film thus obtained can be obtained. The obtained polyimide film can be subjected to further annealing treatment or reverse adhesion treatment (for example, electric treatment such as corona treatment or plasma treatment or blast treatment).

[ flexible  metal Laminates ]

The polyimide film of the present invention can be used, for example, as an insulating film of a flexible metal laminate plate (flexible printed wiring board).

Therefore, the present invention includes a flexible metal laminate comprising the polyimide film of the present invention. Such a flexible metal laminate plate usually comprises a polyimide film and a metal foil.

The kind of the metal constituting the metal foil is not particularly limited, and examples thereof include copper and copper alloys, stainless steel and alloys thereof, nickel and nickel alloys (including 42 alloys), aluminum and aluminum alloys. Preferably copper and copper alloys. It is also possible to use those obtained by forming a waterproof layer or a heat resistant layer (for example, a plating treatment of chrome, zinc or the like), a silane coupling or the like on these metal surfaces. Preferably at least one of copper and / or nickel, zinc, iron, chromium, cobalt, molybdenum, tungsten, vanadium, beryllium, titanium, tin, manganese, aluminum, phosphorus, Alloy, which are preferably used for circuit processing. A particularly preferable metal foil is a copper foil formed by a rolling or electrolytic plating method, and its thickness is preferably 3 to 150 mu m, more preferably 3 to 35 mu m.

The metal foil may be either one which has neither been subjected to any roughening treatment on both sides or one which has been roughened on both sides.

The form of the lamination is not particularly limited as long as the flexible metal laminated plate is provided with a polyimide film and a metal foil. For example, the polyimide film and the metal foil can be directly laminated, The mid film and the metal foil may be laminated.

The adhesive component constituting the adhesive layer is not particularly limited and may be, for example, either a thermosetting resin or a thermoplastic resin. In particular, the adhesive layer may be composed of a thermoplastic polyimide.

Therefore, the present invention also includes an adhesive film (laminated film) having a thermoplastic polyimide layer (an adhesive layer composed of thermoplastic polyimide) on at least one side of the polyimide film.

The thermoplastic polyimide can be obtained by imidizing a polyamic acid which is a precursor. The precursor of the thermoplastic polyimide is not particularly limited, and all known polyamic acids can be used. Also, with respect to the production thereof, well-known raw materials and reaction conditions can be used. In addition, inorganic or organic fillers may be added as needed.

The glass transition temperature of the thermoplastic polyimide may be, for example, about 150 캜 to 350 캜.

The adhesive film can be obtained by providing an adhesive layer containing a thermoplastic polyimide on at least one surface of the polyimide film (non-thermoplastic polyimide film). Specific examples of the production method include a method of forming an adhesive layer on a polyimide film to be a base film, a method of forming an adhesive layer on a sheet, and attaching the adhesive layer to the polyimide film. Among them, when the former method is selected, in view of the fact that imidization of the polyamic acid which is a precursor of the thermoplastic polyimide contained in the adhesive layer may lower the solubility in the organic solvent, It may be difficult to provide an adhesive layer. Therefore, from the above viewpoint, it is more preferable to prepare a solution containing a polyamic acid which is a precursor of the thermoplastic polyimide, apply the solution to the base film, and then imidize the solution.

The method of pouring (coating) and applying the polyamic acid solution to the polyimide film is not particularly limited, and conventional methods such as die coater, reverse coater, and blade coater can be used. When the adhesive layer is continuously formed, the effect of the invention becomes remarkable. That is, the polyimide film obtained as described above is wound and unwound, and a solution containing polyamic acid, which is a precursor of thermoplastic polyimide, is continuously applied. In addition, the polyamic acid solution may contain other materials such as fillers, depending on the application. Further, the thickness of each layer of the heat-resistant adhesive film can be appropriately adjusted to the total thickness depending on the application.

As the imidization method, any of the heat imidization method and the chemical imidization method can be used. In any imidization sequence, the heating is carried out in order to proceed the imidization efficiently. The temperature at that time is preferably from (glass transition temperature -100 ° C) to (glass transition temperature + 200 ° C) of the thermoplastic polyimide (Glass transition temperature of the thermoplastic polyimide: -50 占 폚) to (glass transition temperature + 150 占 폚). If the heating temperature is higher, the imidization is likely to occur, and therefore the imidization speed can be increased, which is preferable from the viewpoint of productivity. However, if it is too high, the thermoplastic polyimide may thermally decompose in some cases. On the other hand, if the heating temperature is too low, the imidization does not progress even under chemical imidization, and the time required for the imidation process becomes long.

Regarding the imidization time, it is not particularly limited if there is a sufficient time to substantially complete imidation and drying.

The thickness of the thermoplastic polyimide is preferably 0.1 탆 or more and 30 탆 or less, more preferably 0.5 탆 or more and 20 탆 or less.

As a method of heat-pressing the non-thermoplastic polyimide and the metal, a polyamic acid and / or a polyimide solution of a thermoplastic polyimide precursor may be applied to the non-thermoplastic polyimide film and dried and then adhered to the metal. A thermoplastic polyimide film is formed by the same method and then adhered to the non-thermoplastic polyimide film, and a hot pressing method and / or a continuous lamination method can be used. As the hot pressing method, for example, a metal foil cut in a predetermined size of a press machine and a polyimide may be overlapped and thermocompression-bonded by a hot press.

The continuous lamination method is not particularly limited, and for example, there is a method of sandwiching and pasting between rolls. The roll may be a metal roll, a rubber roll, or the like. There is no limitation on the material, but a steel material or a stainless material is used as the metal roll. It is preferable to use a treatment roll having a surface hardness such as hard chromium plating and tungsten carbide on its surface. As the rubber roll, it is preferable to use heat-resistant silicone rubber or fluorine rubber on the surface of the metal roll.

In addition, two upper and lower metal rolls, which are called belt laminates, are arranged in pairs and upper and lower seamless rollers in which at least one pair of upper and lower metal rolls are arranged in series are disposed between the two upper and lower seamless rollers. And the laminate can be continuously laminated by heating with a metal roll or other heat source.

As the lamination temperature, a temperature range of 200 to 400 캜 is preferable. It is also preferable to carry out heating annealing after hot press and / or continuous lamination.

The flexible metal laminated sheet of the present invention can be used as a flexible wiring board in which various miniaturized and high-density components are mounted when a desired pattern wiring is formed by etching a metal foil. Needless to say, the use of the present invention is not limited to this, and it goes without saying that the laminated body including the metal foil can be used for various purposes.

The present invention includes various combinations of the above configurations within the technical scope of the present invention as long as the effects of the present invention are exhibited.

[ Example ]

The present invention will now be described more specifically with reference to Examples. However, 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 >

Methods for measuring various characteristics in the present invention are described below.

( Imidization rate )

The imidization rate is relatively indicative of the presence of the imide groups of the object film on the polyimide film of the product. Using a FT-IR 1375cm ^- represented by the ratio of the peak height to obtain by the formula ¹ and 1500cm ^-1.

Imidization rate (%) = A / B x 100

[Wherein, A is (peak height of 1375cm ^-1 in the measurement target film) / (the peak height of the measurement target film 1500cm ^-1), B is (peak height of 1375cm-1 of the polyimide film serving as a reference) / (The peak height of 1500 cm ^-1 of the reference film).

The polyimide film to be used as the reference was a film obtained by drying and heat treatment.

( AI value )

The propagation speed V of the ultrasonic pulse was measured using the following SOM-2500 (Sonic Sheet Tester) manufactured by Nomura. With the SST-2500, ultrasonic velocities in 16 directions are automatically measured every 11.25 ° with respect to the film plane direction 0 to 180 degrees (0 degrees parallel to the MD direction). Anisotoropy Index (AI) is obtained from the maximum speed (MAX) and the minimum speed (MIN) in the obtained directions. Using the films produced by the following examples and comparative examples, measurements were made in the following measurement ranges.

(1): AI = (VMAX ^ 2-VMIN ^ 2) / (VMAX ^ 2 + VMIN ^ 2)

(Where VMAX ^ 2 is the square of the maximum pulse propagation velocity and VMIN ^ 2 is the square of the pulse propagation velocity minimum).

Two points which are 200 mm inward from the both ends of the film width direction in the film width direction (TD direction) are selected, and one point within the central part within ± 200 mm on the straight line including the two points within the range of the straight line connecting the two points Another arbitrary two points are selected, and at least these five points are measured.

The AI value is measured at least five points on a straight line in the film width direction, and the largest AI value (AI value MAX) among the measurement points is shown in the table. In other words, when the anisotropy in the film width direction is maximized, the AI value becomes MAX (indicating the AI value MAX, whereby the AI value is less than the AI value MAX over the entire film width). If the AI value MAX (or the AI value over the entire width) is large, the elongation after the film heat treatment deteriorates, and defects such as wrinkles occur during winding. Further, the dimensional change ratio of the flexible metal laminate obtained by using the polyimide film before and after the removal of the metal foil is disturbed in the film film width direction.

(Thermal expansion coefficient CTE ) And CTE  film Widthwise  Heterogeneity)

TMA-50 (manufactured by Shimadzu Corporation) under the following measurement ranges under the conditions of a measurement temperature range of 50 to 200 占 폚 and a temperature increase rate of 10 占 폚 / min.

Two points which are 200 mm inward from the both ends of the film width direction in the film width direction (TD direction) are selected, and one point within the central part within ± 200 mm on the straight line including the two points within the range of the straight line connecting the two points Other arbitrary two points were selected and measured at least at these five points.

CTE (ppm / DEG C) in the MD direction and CTE (ppm / DEG C) in the TD direction were obtained as average values from the values of the respective measurement points.

CTE (ppm / 占 폚) in the MD direction and CTE (ppm / 占 폚) in the TD direction among the values of the respective measurement points are the difference between the maximum value and the minimum value, And the TD-CTE difference in the width direction (ppm / 占 폚).

(film Widthwise  Ten Shrinkage  Heterogeneity)

The film was cut into 200 mm in the film machine direction (MD direction) and 200 mm in the film width direction (TD direction), and the film dimension (L1) after being left in a room adjusted at 25 캜 and 60% RH for 2 days was measured, After heating at 200 DEG C for 60 minutes, the film was again left in a room adjusted to 25 DEG C and 60RH% for 2 days to measure the film dimension (L2), and the heat shrinkage ratio was determined by the following formula.

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

In addition, unevenness of the heat shrinkage ratio in the film width direction can be obtained by selecting two points that are 200 mm inward from both ends of the film forming width in the film width direction (TD direction), and calculating the two points within the range of the straight line connecting the two points (Center) within ± 200 mm on the straight line including the center, and arbitrary two points different from each other are selected, and at least the film including each of these five points is cut (measured with respect to the center) And the difference between the maximum value and the minimum value.

(film Widthwise  Variation in dimensional change rate)

Based on JIS C6481 5.16, four holes were formed on the center and the diagonal line of the adhesive film of the sample, and the distance from the center to each hole was measured. Subsequently, the metal foil was removed from the flexible metal laminate by attaching a copper foil and an etching process, and then the distance between the four holes was measured in the same manner as before the etching process. The measured value of the distance to each hole before the metal foil removal is D1 and the measured value of the distance to each hole after the metal foil removal is taken as D2 and the dimensional change rate before and after etching Average value).

Dimensional change ratio (%) = {(D2-D1) / D1} 100

Such a dimensional change ratio is obtained by selecting two points which are 200 mm inward from both ends of the film forming width in the film width direction (TD direction) and measuring the center part of the straight line including the two points within the range of the straight line connecting the two points. And the other arbitrary two points were selected and measured at least for these five points, and the difference between the maximum value and the minimum value was determined as the non-uniformity of the dimensional change rate in the film width direction.

The metal laminate plate was produced by laminating an adhesive layer (thermoplastic polyimide layer) on one side of a polyimide film, and then rolling a copper foil on the adhesive layer side. Specifically, a polyamic acid solution of thermoplastic polyimide [1, 3-bis- (4-aminophenoxy) benzene was added to a solvent in dimethylacetamide and stirred until the solution was dissolved. Thereafter, the polyamic acid solution obtained by adding 4,4'-dioxydiphthalic anhydride and stirring was applied so as to have a thickness of 2 占 퐉 after drying, and the resultant was heated at 150 占 폚 for 10 minutes and at 350 占 폚 for 1 minute (Made of an adhesive film). Thereafter, a copper foil was stuck to the thermoplastic polyimide side at 350 DEG C for 30 minutes to produce a flexible metal laminate.

( Heel height  value)

In the following procedure, the elongation value (mm) shown in Fig. 1 (a) was measured. The polyimide film is slit into a rectangular shape having a length of 508 mm and a length of 6.5 m.

This rectangular film was heated in a hot air oven at 200 캜 for 30 minutes in a state in which no external force was applied, and then taken out of the oven.

Unfold the sample on a flat bottom and measure the curvature arc and the maximum distance of the string (tightening extension) when tightened.

(Examples 1 to 5)

(BPDA, molecular weight 294.22) / 4,4'-diaminodiphenyl ether (DPE, molecular weight 200.24) / 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride ) / Para-phenylenediamine (PPD, molecular weight: 108.14) at a molar ratio of 65/35/60/40 and polymerizing to 20 wt% in DMAC (N, N-dimethylacetamide) Azine polyamic acid solution was obtained.

Picoline and anhydrous acetic acid were added to the polyamide solution so that the molar ratio of polyamic acid to polyamic acid was 3.0, and the solution was flowed from the inlet to a stainless steel support at 90 ° C (flexible) A midgel film was obtained.

The gel film was peeled off from the support and conveyed and longitudinally stretched through a nip roll. After longitudinal stretching, both ends of the film were held tightly, and the film was dried in a tenter while being transversely stretched. After drying, heat treatment was performed using an electric heater to obtain a polyimide film.

The thickness of the polyimide film was changed by controlling the ratio of the inlet discharge speed / support rotation speed to obtain a polyimide film having an average thickness of 7.5 to 38 μm.

(Reference Example 1)

4,4'-biphenyltetracarboxylic dianhydride (BPDA, molecular weight 294.22) / 4, 4'-diaminodiphenyl ether (DPE, molecular weight 200.24 ) / Para-phenylenediamine (PPD, molecular weight: 108.14) at a molar ratio of 75/25/60/40 and polymerizing to 20 wt% in DMAC (N, N-dimethylacetamide) Azine polyamic acid solution was obtained.

Picoline and anhydrous acetic acid were added to the polyamide solution so that the molar ratio of polyamic acid to polyamic acid was 3.3, and the solution was allowed to flow on a stainless steel support at 75 DEG C to obtain a self-supporting polyimide gel film .

The gel film was peeled off from the support and conveyed and longitudinally stretched through a nip roll. After longitudinal stretching, both ends of the film were held tightly, and the film was dried in a tenter while being transversely stretched. After drying, heat treatment was performed using an electric heater to obtain a polyimide film.

(Reference Example 2)

(BPDA, molecular weight: 294.22) / 4, 4'-diaminodiphenyl ether (DPE, molecular weight: 200.24) having a molecular weight of 218.12 / 3,3'4,4'-biphenyltetracarboxylic dianhydride ) / Para-phenylenediamine (PPD, molecular weight: 108.14) at a molar ratio of 75/25/60/40 and polymerizing to 20 wt% in DMAC (N, N-dimethylacetamide) Azine polyamic acid solution was obtained.

Picoline and anhydrous acetic acid were added to the polyamide solution so that the molar ratio to the polyamic acid was 2.8, and the solution was flowed (softened) on a stainless steel support at 75 DEG C to prepare a polyimide gel A film was obtained.

The gel film was peeled off from the support and conveyed and longitudinally stretched through a nip roll. After longitudinal stretching, both ends of the film were held tightly, and the film was dried in a tenter while being transversely stretched. After drying, heat treatment was performed using an electric heater to obtain a polyimide film.

(Reference Example 3)

4,4'-biphenyltetracarboxylic dianhydride (BPDA, molecular weight 294.22) / 4, 4'-diaminodiphenyl ether (DPE, molecular weight 200.24 ) / Para-phenylenediamine (PPD, molecular weight 108.14) at a molar ratio of 75/25/60/40 and polymerizing to 20% by weight in DMAC (N, N-dimethylacetamide) Azine polyamic acid solution was obtained.

Picoline and anhydrous acetic acid were added to the polyamide solution so that the molar ratio with respect to the polyamic acid was 2.5, and the solution was flowed (softened) on a stainless steel support at 75 DEG C to prepare a polyimide gel A film was obtained.

The gel film was peeled off from the support and conveyed and longitudinally stretched through a nip roll. After longitudinal stretching, both ends of the film were held tightly, and the film was dried in a tenter while being transversely stretched. After drying, heat treatment was performed using an electric heater to obtain a polyimide film.

(Reference Example 4)

4,4'-biphenyltetracarboxylic dianhydride (BPDA, molecular weight 294.22) / 4, 4'-diaminodiphenyl ether (DPE, molecular weight 200.24 ) / Para-phenylenediamine (PPD, molecular weight: 108.14) at a molar ratio of 65/35/82/18 and polymerizing to 20 wt% in DMAC (N, N-dimethylacetamide) Azine polyamic acid solution was obtained.

To the polyamide solution, β-picoline and anhydrous acetic acid were added so as to have a molar ratio of 2.8 to the polyamic acid, respectively, and then flowed on a stainless steel support at 95 ° C. to give a polyimide gel A film was obtained.

The gel film was peeled off from the support and conveyed and longitudinally stretched through a nip roll. After longitudinal stretching, both ends of the film were held tightly, and the film was dried in a tenter while being transversely stretched. After drying, heat treatment was performed using an electric heater to obtain a polyimide film.

The composition of the polyimide, preparation conditions of the polyimide film, and various physical properties of the polyimide film are summarized in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Reference Example 1 Reference Example 2 Reference Example 3 Reference Example 4 PMPA / BPDA / DPE / PPD (molar ratio) 65/35/60/40 65/35/60/40 65/35/60/40 65/35/60/40 65/35/60/40 75/25/60/40 75/25/60/40 75/25/60/40 65/35/82/18 The molar ratio of? -Picoline and anhydrous acetic acid to polyamic acid 3.0 3.0 3.0 3.0 3.0 3.3 2.8 2.5 2.8 Temperature of support (℃) 90 90 90 90 90 75 75 75 95 Imidization rate (%) of the gel film after peeling from the support 62 59 62 65 70 52 39 35 64 Drawing magnification (MD direction) 1.23 1.25 1.20 1.23 1.23 1.22 1.22 1.13 1.27 The stretching magnification (TD direction) 1.50 1.55 1.50 1.50 1.50 1.50 1.50 1.30 1.55 Film thickness (탆) 20.5 7.5 12.6 24.8 37.8 24.6 37.6 49.4 17.1 Film width (mm) 2000 2000 2000 2000 2000 2000 2000 2000 2000 AI Value MAX 9.4 11.5 7.9 13.1 12.6 29.9 18.8 21 7.2 CT in the MD direction (ppm / ° C, average value) 3.2 2.7 4.1 3.3 3.6 3.5 3 5.2 12.7 CTE in the TD direction (ppm / DEG C, average value) 3.4 2.5 3.8 3.2 3.1 3.6 3.6 4.4 14.2 MD-CTE difference in film width direction (ppm / ° C, difference between maximum value and minimum value) 0.5 0.6 1.4 1.2 1.4 0.5 0.6 0.2 0.5 TD-CTE difference in film width direction (ppm / ° C, difference between maximum value and minimum value) 1.5 0.6 1.6 0.9 0.7 1.5 0.6 0.2 2.1 Imidization rate (%) of the gel film after peeling from the support 62 59 62 65 70 52 39 35 64 Difference in heat shrinkage at 200 ℃ in film width direction (%, difference between maximum value and minimum value) 0.01 0.02 0.02 0.02 0.02 0.06 0.06 0.05 0.05 The half-elongation value (mm) 3 One 3 3 0 5 5 6 10 Non-uniformity of dimensional change in film width direction (%, difference between maximum value and minimum value) 0.03 0.03 0.02 0.04 0.04 0.08 0.06 0.07 0.06

From the above results, it was confirmed that the polyimide film of the present invention had small nonuniformity in dimensional change in the film width direction and little deviation.

The polyimide film of the present invention is useful for flexible printed wiring boards and the like.

1: rectangular shape film
2: Film end
a: the elongation value

Claims (7)

The anisotropy index AI value in the following equation when measuring the propagation velocity V of the ultrasonic pulse is not more than 7 ppm / DEG C both in the machine direction (MD) of the film and in the width direction (TD) Polyimide film having a width of 15 or less:
AI = (VMAX ^ 2-VMIN ^ 2) / (VMAX ^ 2 + VMIN ^ 2)
In the above equation, VMAX ^ 2 is the square of the pulse propagation velocity maximum value, and VMIN ^ 2 is the square of the pulse propagation velocity minimum value.
The polyimide film according to claim 1, wherein the film-forming width is 1000 mm or more and the difference in coefficient of linear expansion in the film width direction of? MD is 2 ppm / 占 폚 or less.
The polyimide film according to claim 1 or 2, wherein the film-forming width is 1000 mm or more and the difference in coefficient of linear expansion in the film width direction of? TD is 2 ppm / 占 폚 or less.
The polyimide film according to any one of claims 1 to 3, wherein the polyimide film comprises an aromatic diamine component containing p-phenylenediamine, pyromellitic dianhydride and 3,3'-4,4'-diphenyltetracarboxylic dianhydride And a polyimide having at least one acid anhydride component selected from the group consisting of a polyimide as a polymerization component.
A polyimide precursor solution was applied on the support to prepare a gel film having a self-supporting property partially dried and cured,
The method for producing a polyimide film according to any one of claims 1 to 4, wherein the gel film is held tightly at both ends in the width direction, and is subjected to drying and heat treatment through a heating furnace.
The production method according to claim 5, wherein the imidization ratio of the gel film is 55% to 75%.
A flexible metal laminate comprising the polyimide film according to any one of claims 1 to 4 and a metal foil.

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