KR20100048474A - Flexible metal-clad laminate and a method of manufacturing the same - Google Patents

Abstract

PURPOSE: A flexible metal-clad laminate and a method of manufacturing the same are provided to obtain an excellent outer shape after an imides reaction, to prevent the metal-clad laminate from being bent, and to obtain excellent adhesive force with a metal film. CONSTITUTION: A flexible metal-clad laminate comprises: a first polyimide layer which is located on the one side of a metal film and has a glass transition temperature of 300~500; a second polyimide layer which is located on one side of the first polyimide layer and has a coefficient of linear thermal expansion of 1~20ppm / K; and a thermoplastic polyimide layer which is located on one side of the second polyimide layer.

Description

Flexible metal-clad laminate and a method of manufacturing the same

The present invention relates to a flexible metal laminate and a method for manufacturing the same, and more particularly, to a flexible metal laminate and a method for manufacturing the same.

Flexible Metal Clad Laminate, used in the manufacture of Flexible Printed Ciruit Board, is a laminate of conductive metal foil and insulating resin, which enables fine circuit processing and Flexibility is possible, and the use of electronic devices is increasing along with the trend of miniaturization and light weight.

Such flexible metal laminates are divided into two-layer and three-layer methods, and the three-layer method using an adhesive is inferior in heat resistance and flame retardancy compared to the two-layer method, and has a large problem in dimensional change during the heat treatment process. For this reason, in the manufacture of flexible printed circuit boards, the recent trend is to use flexible metal laminates of two-layer type rather than three-layer type.

Recently, the use of double-sided metal laminates is increasing due to the light and short circuit trend of circuits. The double-sided metal foil laminate is generally manufactured by laminating a thermoplastic polyimide of the outermost layer of a polyimide resin used as an insulating resin with a metal foil. In this case, the flexible copper foil laminate before and after etching due to the presence of the thermoplastic polyimide resin ( curling) occurred.

Accordingly, in Korean Patent Publication Nos. 10-2004-0084028, 2006-0129081, or 2003-0079991, a polyimide precursor solution is used to control the warp before and after the etching of the double-sided metal foil laminate and to improve adhesion to the metal foil. A method of applying and drying a plurality of times has been proposed. However, the proposed methods use thermoplastic polyimide (TPI, Thermoplastic Polyimide) as a polyimide resin directly applied to the metal foil, and thus can maintain a high adhesive strength with the metal foil to be coated, but the Republic of Korea Patent Publication No. 10-2004-0084028 Since the thermoplastic polyimide resin in contact with the metal foil generally has a low glass transition temperature of 200 ° C to 250 ° C, blistering of the surface of the polyimide during the imidization process, between the polyimide resin layers or at the polyimide resin and the metal foil interface Appearance defects such as delamination are easy to occur, and Korean Patent Publication No. 2006-0129081 requires thinning of the thermoplastic polyimide layer to match the coefficient of thermal expansion of the polyimide resin with that of metal. , Korean Patent Publication No. 2003-0079991 shows that the amount of expensive thermoplastic polyimide There was a growing problem.

In order to solve the above problems, an object of the present invention is to provide a flexible metal laminate having excellent appearance after imidization, no bending before and after etching, and excellent adhesion to metal foil and dimensional stability after etching. To provide.

In addition, another object of the present invention is to provide a metal foil laminate and a method for manufacturing the same, which can be used as a double-sided metal foil laminate by producing a metal foil through a laminating (Laminating) process.

In order to achieve the above object, the present invention is located on one surface of the metal foil, the first polyimide layer having a glass transition temperature of 300 ~ 500 ℃; A second polyimide layer positioned on one surface of the first polyimide layer and having a linear thermal expansion coefficient of 1 to 20 ppm / K; It provides a flexible metal laminate comprising a; a thermoplastic polyimide layer located on one surface of the second polyimide layer.

The present invention comprises the steps of (a) applying a polyamic acid solution located on one surface of the metal foil and the glass transition temperature after the imidization is 300 ~ 500 ℃ to form a first polyimide layer after drying; (b) applying a polyamic acid solution having a linear thermal expansion coefficient of 1 to 20 ppm / K after imidization to one surface of the formed first polyimide layer to form a second polyimide layer after drying; (c) Applying a thermoplastic polyamic acid solution having a glass transition temperature of 200 ° C. ≦ Tg ≦ 300 ° C. and a thermal expansion coefficient of 30 to 200 ppm / K after imidization is applied to one surface of the formed second polyimide layer, the thermoplastic poly Forming a mid layer; And (d) imidizing the prepared laminate by heat treatment at 0 to 500 ° C .; It provides a method for producing a flexible metal laminate comprising a.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In the business card for describing the present invention, detailed descriptions of related known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

The terms " about ", " substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation to or in the numerical value of the manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The present invention is ① polyimide layer having a glass transition temperature (Tg) of 300 ~ 500 ℃ (hereinafter referred to as 'first polyimide layer'), ② is located on the other side of the first polyimide layer described above and the coefficient of linear thermal expansion 1 to 20 ppm / K polyimide layer (hereinafter referred to as 'second polyimide layer'), ③ thermoplastic polyimide resin layer present on the other side of the second polyimide layer (hereinafter referred to as 'thermoplastic polyimide layer') It relates to a flexible metal laminate and a double-sided flexible metal laminate obtained by laminating it.

The laminate according to the present invention is excellent in appearance after thermal imidization, no curling before and after etching, and excellent in adhesive strength with metal foil and dimensional stability after etching. In addition, the laminate manufactured according to the present invention may be manufactured by double-sided metal laminate by laminating another metal foil on one surface of the thermoplastic polyimide layer.

The first polyimide layer located on one surface of the metal foil has a linear thermal expansion coefficient of 5 to 40 ppm / K. In particular, it is preferable that the first polyimide layer has a higher coefficient of linear thermal expansion in the range of 5 to 25 ppm / K as compared with the second polyimide layer. In this case, a stable adhesion of 1.0 kgf / cm or more, more preferably 1.0 kgf / cm to 3.0kgf / cm, may be maintained with the applied metal foil, and the metal foil may be moved inward due to the difference in coefficient of thermal expansion with the second polyimide layer. Since the bending stress is formed, the bending of the laminate by the thermoplastic polyimide layer having a high coefficient of thermal expansion can be eliminated.

The first polyimide layer in contact with the metal foil is more preferably 300 ° C to 500 ° C although a resin having a glass transition temperature of 300 ° C or higher is used. It is common to use thermoplastic polyimide resin as the first polyimide layer, but in this case, due to the low glass transition temperature, blistering of the surface during the imidization process, between the polyimide resin layers or between the polyimide resin and the metal foil interface There is a problem in that appearance defects such as delamination occur. Therefore, in order to prevent appearance defects during the imidization process, the first polyimide layer in contact with the metal foil should use a low thermal expansion polyimide resin having a glass transition temperature of 300 ° C. or higher.

The second polyimide layer located on one surface of the first polyimide layer has a linear thermal expansion coefficient of 20 ppm / K or less, and more preferably 1 to 20 ppm / K. The use of a low thermal expansion coefficient polyimide resin as the second polyimide layer overcomes the high coefficient of thermal expansion of the thermoplastic polyimide layer and adjusts the coefficient of thermal expansion of the entire polyimide resin to be similar to that of the metal foil. to be. This prevents the warping of the laminate before and after etching, and can control the dimensional change rate after etching from -0.1 to + 0.1%, more preferably from -0.05% to + 0.05%.

If the 1st polyimide layer or the 2nd polyimide layer expresses normal low thermal expansion property, there will be no restriction | limiting in a composition.

As the material forming the polyimide layer, tetracarboxylic anhydride and a diamino compound may be commonly used, but are not limited thereto.

As tetracarboxylic acid anhydride for expressing low thermal expansion, pyromellitic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride (3,3', 4,4'- biphenyltetracarboxylic acid dianhydride), 3,3 ', 4,4'-benzophenonetetracarboxylic acid dianhydride (3,3', 4,4'-benzophenonetetracarboxylic acid dianhydride), and the like.

Also preferred as diamino compounds are 4,4'-diaminophenyl ether, p-phenylenediamine, 4,4'-thiobisbenzeneamine (4,4). '-thiobisbenzenamine)' is useful.

The low thermally expandable polyimide resin of the present patent includes a polyimide resin of the following [Formula 1].

[Formula 1]

In all the components of the above [Formula 1], 0.5 ≦ m ≦ 1.0, 0 ≦ n ≦ 0.5, and m + n = 1.

X and Y included in [Formula 1] are each independently an aromatic dianhydride compound selected from the following.

On the other hand, as long as the thermoplastic polyimide resin has sufficient fluidity at the glass transition temperature or higher, the composition is not limited, and the thermoplastic polyimide resin may be fluidized by pressurization. Also included are those prepared using a single dianhydride monomer and a single diamine monomer, as well as those prepared by copolymerizing two or more dianhydrides and two or more diamine monomers.

The thermoplastic polyimide layer of the present invention may have a glass transition temperature of 200 ° C. ≦ Tg ≦ 300 ° C. and a thermal expansion coefficient of 30 to 200 ppm / K. More specifically, the thermoplastic polyimide resin constituting the thermoplastic polyimide layer of the present invention may include 30 to 100% by weight of a repeating unit (hereinafter referred to as a thermoplastic repeating unit) including W and Z in the following [Formula 2]. It is suitable. When the fraction of the thermoplastic repeating unit is less than 30%, there is a problem in that the thermoplastic polyimide layer has insufficient fluidity, and thus, thermal compression is impossible in manufacturing double-sided products, or the adhesive strength with the metal to be compressed is lowered. Therefore, the fraction of the thermoplastic repeating unit needs to be carefully controlled in consideration of the glass transition temperature of the thermoplastic polyimide layer. Considering the laminating process for the production of double-sided products, the glass transition temperature of the thermoplastic polyimide resin is appropriate level of 200 ℃ ~ 300 ℃.

[Formula 2]

Wherein m, n are real numbers where m + n = 1, 0.3 ≦ m ≦ 1, 0 ≦ n ≦ 0.7.

W contained in the above [Formula 2] is an aromatic diamino compound selected from, and these may be used alone or copolymerized.

W ₁ is selected from-(CH ₂ )-,-(CH ₂ ) n-, -CH ₂ -C (CH ₂ ) ₂ -CH _2- ,

W ₂ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- Become,

W ₃ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- Become,

W ₄ is selected from -O-, -CO-,

W ₅ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- Become,

W ₆ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- do.

More preferably, W contained in [Formula 2] is an aromatic diamino compound selected from the following, and these may be used alone or in copolymerization.

W ₃ , W ₅ , W ₆ are -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-( CH ₂ )-.

Z contained in [Formula 2] is an aromatic dianhydride selected from the following, and these may be used alone or copolymerized.

P contained in the above [Formula 2] may be used alone or copolymerized as an aromatic diamino compound selected from the following.

P ₁ is a compound selected from -O-, -CONH-,

P ₂ is a compound selected from -H, -CH ₃ , -CF ₃ ,

Q contained in the above [Formula 2] is an aromatic dianhydride selected from, and can be used alone or copolymerized.

The polyimide resin mentioned in the present invention includes all resins having an imide ring as shown in the following [Formula 3], and examples thereof include polyimide, polyamideimide, polyesterimide, and the like.

(3)

Ar and Ar ₂ in the above [Formula 3] is a (C6-C20) aryl group, n = 1 ~ 10,000,000 is a real number selected.

However, as long as it has the desired properties in the present invention, no particular limitation is imposed on the composition of the polyimide resin, and the polyimide resin alone, derivatives thereof, or a mixture of two or more of the foregoing alone and derivatives may be used. In addition, curing accelerators such as pyridine and quinoline, silane coupling agents, titanate coupling agents, adhesion imparting agents such as epoxy compounds, defoamers to facilitate the application process, and leveling You may use other additives, such as an agent.

The present invention comprises the steps of (a) applying a polyamic acid solution located on one surface of the metal foil and the glass transition temperature after the imidization is 300 ~ 500 ℃ to form a first polyimide layer after drying; (b) applying a polyamic acid solution having a linear thermal expansion coefficient of 1 to 20 ppm / K after imidization to one surface of the formed first polyimide layer to form a second polyimide layer after drying; (c) Applying a thermoplastic polyamic acid solution having a glass transition temperature of 200 ° C. ≦ Tg ≦ 300 ° C. and a thermal expansion coefficient of 30 to 200 ppm / K after imidization is applied to one surface of the formed second polyimide layer, the thermoplastic poly Forming a mid layer; And (d) imidizing the prepared laminate by heat treatment at 0 to 500 ° C .; It provides a method for producing a flexible metal laminate comprising a.

The drying temperature after application of the polyamic acid solution, which is a precursor resin of the polyimide, in step (a) to (c) is not limited, but is preferably 80 to 220 ° C. The polyamic acid passed through the steps (a) to (c) becomes a gel film in a solid state having self-supportability coated on the copper foil. When the drying temperature of the polyamic acid is less than 80 ° C., the solvent volatilization rate is insignificant, so that it is difficult to exert a substantial drying effect. If the drying temperature is higher than 220 ° C., the coating layer may be excessively cured, thereby deteriorating physical properties or exhibiting stable physical properties. .

According to the present invention, each of the first polyimide layer, the second polyimide layer, and the thermoplastic polyimide layer present on one surface of the metal foil is coated with a convertible polyimide precursor resin a plurality of times and dried, and then converted into a polyimide resin through infrared heat treatment. Provided is a converted flexible metal laminate.

The polyimide resin included in each layer may be applied directly onto the metal foil of the polyimide resin itself or the semi-cured polyimide resin, but in general, after the application of the polyimide precursor solution, thermal or chemical conversion is performed. It is common to convert to polyimide resin via. As a heat treatment method, any method may be applied, but after forming a gel film by applying and drying a semi-cured polyimide resin or polyimide precursor resin, it is allowed to stand for a predetermined time in a drying furnace at a predetermined temperature. It is common to heat treatment by moving the inside of the drying or for a predetermined time continuously. Heat processing temperature is 300 degreeC or more normally, More preferably, high temperature processing of 300-500 degreeC is performed.

As the heat treatment method, a known heating method can be applied as long as the object of the present invention is satisfied. It is common to use the hot air heating furnace of nitrogen atmosphere normally. However, in this case, a difference in curing history occurs in the thickness direction of the film, so that uniform heat treatment is impossible, and in the case of a thick film film, it is difficult to remove the solvent present in the film, thereby deteriorating dimensional stability. Therefore, in order to heat-treat the laminate of the present invention, it is preferable to use an infrared heating furnace capable of uniform heat treatment in the thickness direction of the film. Through this, the dimensional change rate after etching is -0.1 to + 0.1%, and preferably a ductile metal laminate having excellent dimensional stability of -0.05 to + 0.05% can be produced.

Coating methods applicable to the application of each layer of the present invention include knife coating, roll coating, die coating, curtain coating, and the like. There is no limit to the method as long as it satisfies the purpose pursued.

The double-sided metal laminate described in the present invention can be produced by laminating a new metal foil in addition to the thermoplastic polyimide layer of the laminate of the metal foil, the first polyimide layer, the second polyimide layer and the thermoplastic polyimide. No particular limitation is imposed on the laminating temperature, but it is necessary to heat it to a temperature above the glass transition temperature of the thermoplastic polyimide resin. When the heating temperature of the thermoplastic polyimide resin is not sufficient, sufficient fluidity necessary for pressing with the metal foil cannot be secured, and thus, it is impossible to secure stable adhesive force. It is appropriate that the heating temperature at the time of pressing is usually 30 to 100 ° C. higher than the glass transition temperature (Tg) of the thermoplastic polyimide resin. In addition, about laminating pressure, 50-200 kgf / cm is suitable as a line pressure. If the pressure is high, it is advantageous to lower the laminating temperature, so it is advantageous to work at the higher pressure possible.

The present invention provides a flexible metal laminate having a peel strength of 1.0 to 3.0 kgf / cm at a first polyimide layer and a metal foil interface. In addition, the present invention can maintain a stable adhesive strength by providing a flexible metal foil laminate having a peel strength (Peel Strength) of 1.0 ~ 3.0kgf / cm at the laminated metal foil interface further laminated with the thermoplastic polyimide.

As described above, the flexible metal foil laminate according to the present invention has an excellent appearance after imidization, no curling before and after etching, and excellent adhesion to the metal foil.

In addition, the laminate produced according to the present invention may be produced as a double-sided metal laminate through a laminating process.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereto.

Abbreviations used in the following examples are as follows.

-DMAc: N, N-dimethylacetamide

-BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-biphenyltetracarboxylic acid dianhydride)

-PDA: para-phenylenediamine

-ODA: 4,4'-diaminodiphenylether

-TPE-R: 1,3-bis (4-aminophenoxy) benzene

-BAPB: 4,4'-bis (4-aminophenoxy) biphenyl (4,4'-bis (4-aminophenoxy) biphenyl)

The physical properties mentioned in the present invention were followed by the following measurement method.

1. Measurement of coefficient of thermal linear expansion (CTE) and glass transition temperature (Tg)

 The coefficient of linear thermal expansion was obtained by averaging between 100 ° C and 250 ° C of the measured thermal expansion using TMA (Thermomechanical Analyzer) at a rate of 5 ° / min. In addition, the inflection point of the thermal expansion curve measured through the above process was defined as the glass transition temperature (Tg).

2. Curing before and after etching

In order to measure the curl of the laminate before and after etching, the samples were cut into squares each having a width of 30 cm and a length of 30 cm, and then the heights of the corners were measured and averaged. When the average value did not exceed 1 cm, it looked as the flat laminated body.

3. Adhesion between polyimide resin and metal foil

In order to measure the peel strength of the polyimide resin and the metal layer, the metal layer of the laminate was patterned to a width of 1 mm, and then 180 ° peeling strength was measured using a universal testing machine (UTM).

4. Observation of appearance of polyimide resin

The shape of the surface was observed after cutting the laminate into squares having a width of 30 cm and a length of 30 cm, respectively.

5. Dimensional change rate after etching

Method B of IPC-TM-650, 2.2.4 was followed. Holes for position recognition were drilled at four vertices of square specimens with MD and TD of 275 × 255 mm, respectively, and stored at 23 ° C. and 50% RH for 24 hours. The distance between the holes was averaged three times. After that, the metal foil was etched, and stored at a constant temperature and humidity chamber at 23 ° C. and 50% RH for 24 hours, and then the distance between the holes was measured again. The rate of change of the measured values in the MD and TD directions was calculated.

[Production Example 1]

12,312 g of PDA and 2,533 g of diamine were dissolved in 211,378 g of DMAc solution under a nitrogen atmosphere and completely dissolved, and then 38,000 g of BPDA was added several times as dianhydride. Thereafter, stirring was continued for about 24 hours to prepare a polyamic acid solution. The polyamic acid solution thus prepared was cast to a film having a thickness of 20 μm, and then heated to 350 ° C. for 60 minutes and held for 30 minutes to cure. The measured glass transition temperature and coefficient of thermal expansion were 12.0 ° C. and 342 ppm / K, respectively.

[Production Examples 2 to 8]

It was prepared using the composition and content of [Table 1] in the same manner as in Preparation Example 1.

Table 1

division Dianhydride Diamine 1 Diamine 2 DMAc Coefficient of thermal expansion (C.T.E, ppm / K) Tg (℃) Preparation Example 1 BPDA, 38,000 g PDA, 12,312g ODA, 2,533 g 211,378 g 12.0 342 Production Example 2 BPDA, 12,000g PDA, 3,063 g ODA, 2,431 g 117,072 g 24.1 323 Production Example 3 BPDA, 7,000 g PDA, 2380g ODA, 232 g 33,108g 9.8 351 Preparation Example 4 BPDA, 14,000g PDA, 4,032 g ODA, 1,866 g 82,063 g 13.3 321 Preparation Example 5 BPDA, 3300 g PDA, 606g TPE-R, 1,639 g 38,227 g 40.7 234 Preparation Example 6 BPDA, 757 g BAPB 948 - 11,572g 65.11 259 Preparation Example 7 BPDA, 2800 g TPE-R 2,782 g - 38,475 g 50.8 232 Preparation Example 8 BPDA, 1500 g ODA, 1,021 g - 22,688 g 47.3 281

Example 1

The polyamic acid solution prepared through [Preparation Example 2] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 12 μm was applied so as to have a thickness of 5 μm after final curing, followed by drying at 130 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 3] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 13 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. After that, the thermoplastic polyamic acid solution prepared by [Production Example 8] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 3.5 μm after the final curing, and dried at 150 ° C., and the polyamic acid precursor laminated on the copper foil. A film was prepared. The laminate thus prepared was heat treated for 9 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize. The results are shown in [Table 2].

Example 2

The polyamic acid solution prepared through [Preparation Example 2] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 12 μm was applied so as to have a thickness of 5 μm after final curing, followed by drying at 160 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 3] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 13 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. Thereafter, the thermoplastic polyamic acid solution prepared through [Preparation Example 7] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 3 μm after the final curing, and then dried at 150 ° C., and the polyamic acid precursor laminated on the copper foil. A film was prepared. The laminate thus prepared was heat treated for 9 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize. The results are shown in [Table 2].

Example 3

The polyamic acid solution prepared through [Preparation Example 2] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 12 μm was applied so as to have a thickness of 5 μm after final curing, followed by drying at 160 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 3] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 13 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. After that, the thermoplastic polyamic acid solution prepared through [Preparation Example 6] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 3 μm after the final curing, and dried at 160 ° C., and the polyamic acid precursor laminated on the copper foil. A film was prepared. The laminate thus prepared was heat treated for 10 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize. The results are shown in [Table 2].

Example 4

The polyamic acid solution prepared through [Preparation Example 2] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 18 μm was applied so as to have a thickness of 5 μm after final curing, followed by drying at 160 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 1] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 18 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. After that, the thermoplastic polyamic acid solution prepared through [Preparation Example 5] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 3 μm after final curing, and then dried at 150 ° C., and the polyamic acid laminated on the copper foil. A precursor film was prepared. The laminate thus prepared was heat treated for 10 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize. The results are shown in [Table 2].

Comparative Example 1

The polyamic acid solution prepared through [Preparation Example 2] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 12 μm was applied so as to have a thickness of 5 μm after final curing, followed by drying at 130 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 3] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 13 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. The laminate thus prepared was heat treated for 9 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize. The results are shown in [Table 3].

Comparative Example 2

The polyamic acid solution prepared through [Production Example 4] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 18 μm was applied so as to have a thickness of 18 μm after final curing, and then dried at 150 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 7] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 3 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. The laminate thus prepared was heat treated for 7 minutes from 150 ° C. to 395 ° C. under a nitrogen atmosphere to completely imidize the laminate. The results are shown in [Table 3].

Comparative Example 3

The polyamic acid solution prepared through [Preparation Example 7] was applied on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 18 μm so as to have a thickness of 2 μm after final curing, and then dried at 180 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 3] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 22 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. After that, the thermoplastic polyamic acid solution prepared through [Preparation Example 7] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 2 μm after final curing, and then dried at 150 ° C., and the polyamic acid precursor laminated on the copper foil. A film was prepared. The laminate thus prepared was heat treated for 9 minutes from 150 ° C. to 395 ° C. under nitrogen atmosphere to completely imidize the laminate. The results are shown in [Table 3].

Comparative Example 4

The polyamic acid solution prepared through [Preparation Example 8] on an electrolytic copper foil (roughness Rz = 2.0 μm) having a thickness of 18 μm was applied so as to have a thickness of 2.5 μm after final curing, and then dried at 130 ° C. to form a first polyimide precursor layer. Formed. The polyamic acid solution prepared through [Preparation Example 1] was applied to one surface of the first polyimide precursor layer so as to have a thickness of 20 μm after final curing, and then dried at 150 ° C. to form a second polyimide precursor layer. Thereafter, the thermoplastic polyamic acid solution prepared through [Preparation Example 8] was applied to one surface of the second polyimide precursor layer so as to have a thickness of 3 μm after final curing, and dried at 180 ° C., and the polyamic acid precursor laminated on the copper foil. A film was prepared. The laminate thus prepared was heat treated for 24 minutes from 230 ° C. to 385 ° C. under nitrogen atmosphere to completely imidize the laminate. The results are shown in [Table 3].

TABLE 2

division Example 1 Example 2 Example 3 Example 4 Metal foil and roughness (Rz) Electrolytic Copper Foil Thickness 12㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 12㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 12㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 18㎛ Roughness 2㎛ Composition (thickness, μm) Preparation Example 2 / Preparation Example 3 / Preparation Example 8 (5/13 / 3.5) Preparation Example 2 / Preparation Example 3 / Preparation Example 7 (5/13/3) Preparation Example 2 / Preparation Example 3 / Preparation Example 6 (5/13/3) Preparation Example 2 / Preparation Example 1 / Preparation Example 5 (5/18/3) Curling Before Etching Good Good Good Good Curing After Etching Good Good Good Good Exterior after imidization Good Good Good Good Adhesion with Copper Foil (kgf / cm) 1.0 1.1 1.0 1.0 Dimensional change rate after etching (MD / TD,%) 0.04 / 0.03 0.00 / 0.01 -0.01 / -0.01 -0.01 / -0.01

[Table 3]

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Metal foil and roughness (Rz) Electrolytic Copper Foil Thickness 12㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 18㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 12㎛ Roughness 2㎛ Electrolytic Copper Foil Thickness 18㎛ Roughness 2㎛ Composition (thickness, μm) Preparation Example 2 / Preparation Example 3 / (5/13) Preparation Example 4 / Preparation Example 7 (18/3) Preparation Example 7 / Preparation Example 3 / Preparation Example 7 (2/22/2) Preparation Example 8 / Preparation Example 1 / Preparation Example 8 (2.5 / 20/3) Curling Before Etching Copper foil bent inward Resin bent inward - - Curing After Etching Copper foil bent inward Resin bent inward - - Exterior after imidization Good Good Bad Bad

1 is an external appearance photograph of the metal foil surface of Example 1 of the present invention. Referring to FIG. 1, the appearance of the metal foil of the present invention was satisfactorily shown without bubble formation, swelling, and delamination between the metal foil and the polyimide resin or the polyimide resin, whereas FIG. 2, by using a resin having a glass transition temperature of 232 ° C. lower than 300 ° C. in the first polyimide layer, bubbles may be generated on the surface of the metal foil, resulting in poor appearance.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

1 is a photograph of the surface appearance of the metal foil of Example 1 of the present invention.

Figure 2 is a photograph of the surface appearance of the metal foil of Comparative Example 3.

Claims (15)

A first polyimide layer positioned on one surface of the metal foil and having a glass transition temperature of 300 to 500 ° C; A second polyimide layer positioned on one surface of the first polyimide layer and having a linear thermal expansion coefficient of 1 to 20 ppm / K; And A thermoplastic polyimide layer located on one surface of the second polyimide layer; Flexible metal laminate comprising a. The method of claim 1, A flexible metal foil laminate in which metal foil is further laminated on one surface of the thermoplastic polyimide layer. The method of claim 2, Peel strength at the interface between the thermoplastic polyimide and the metal foil (Peel Strength) is 1.0 ~ 3.0kgf / cm soft metal laminate. The method of claim 1, Each of the first polyimide layer, the second polyimide layer, and the thermoplastic polyimide layer on one surface of the metal foil is coated with a convertible polyimide precursor resin a plurality of times and dried, and then converted into a polyimide resin through infrared heat treatment. sieve. The method of claim 1, The first polyimide layer is a flexible metal laminate having a linear thermal expansion coefficient of 5 ~ 40ppm / K. The method of claim 1, The thermoplastic polyimide layer has a glass transition temperature of 200 ° C. ≦ Tg ≦ 300 ° C. and a thermal expansion coefficient of 30 to 200 ppm / K. The method of claim 1, Peel strength at the interface between the first polyimide layer and the metal foil (Peel Strength) is 1.0 ~ 3.0kgf / cm soft metal laminate. The method of claim 1, The flexible metal laminate is A ductile metal laminate with dimensional change after etching of -0.05% to + 0.05%. The method of claim 5, The flexible metal foil laminate according to claim 1, wherein the resin forming the first polyimide layer or the second polyimide layer is represented by the following [Formula 1]. [Formula 1]

Among all the components of [Formula 1], 0.5 ≦ m ≦ 1.0, 0 ≦ n ≦ 0.5, and m + n = 1; X and Y contained in the above [Formula 1] are each independently the same or different as the aromatic dianhydride compound selected from the following structure.

The method of claim 6, The thermoplastic polyimide layer is a flexible metal foil laminate, which is a resin represented by the following [Formula 2]. [Formula 2]

Wherein m, n are real numbers where m + n = 1, 0.3 ≦ m ≦ 1, 0 ≦ n ≦ 0.7. W contained in the above [Formula 2] is an aromatic diamino compound selected from, and these may be used alone or copolymerized.

W ₁ is selected from-(CH ₂ )-,-(CH ₂ ) n-, -CH ₂ -C (CH ₂ ) ₂ -CH _2- , W ₂ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- Become, W ₃ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH3) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- , W ₄ is selected from -O-, -CO-, W ₅ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- Become, W ₆ is selected from -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,-(CH ₂ )- do. Z contained in [Formula 2] is an aromatic dianhydride selected from the following, and these may be used alone or copolymerized.

P contained in the above [Formula 2] may be used alone or copolymerized as an aromatic diamino compound selected from the following.

P ₁ is a compound selected from -O-, -CONH-, P ₂ is a compound selected from -H, -CH ₃ , -CF ₃ , Q contained in the above [Formula 2] is an aromatic dianhydride selected from, and can be used alone or copolymerized.

The method of claim 10, W contained in the above [Formula 2] is an aromatic diamino compound selected from, and these may be used alone or copolymerized.

W ₃ , W ₅ , W ₆ are -O-, -CO-, -S-, -SO _2- , -C (CH ₃ ) _2- , -CONH-, -C (CF ₃ ) ₂ -,- (CH ₂ )-. (a) applying a polyamic acid solution located on one surface of the metal foil and having a glass transition temperature of 300 ° C. to 500 ° C. after imidization to form a first polyimide layer after drying; (b) applying a polyamic acid solution having a linear thermal expansion coefficient of 1 to 20 ppm / K after imidization to one surface of the formed first polyimide layer to form a second polyimide layer after drying; (c) Applying a thermoplastic polyamic acid solution having a glass transition temperature of 200 ° C. ≦ Tg ≦ 300 ° C. and a thermal expansion coefficient of 30 to 200 ppm / K after imidization is applied to one surface of the formed second polyimide layer, the thermoplastic poly Forming a mid layer; And (d) imidating the prepared laminate by heat treatment at 0 to 500 ° C .; Method for producing a flexible metal laminate comprising a. The method of claim 12, Method for producing a flexible metal laminate of the drying temperature in the step (a) is 80 ~ 220 ℃. The method of claim 12, The coating method of each layer is ductile using a method selected from the group consisting of knife coating, roll coating, die coating, curtain coating, and mixing thereof Method for producing a metal laminate. The method of claim 12, The heat treatment of step (d) is a method of producing a flexible metal laminate using an infrared heating furnace in a nitrogen atmosphere.

Images