KR20070105692A - Monomer for synthesizing polyimide, and polyimide precursor and flexible metal clad laminate including the same - Google Patents

Abstract

A monomer of 4,4'-oxybis[N-(4-amino-2-alkoxyphenyl)benzamide] is provided to have high flex resistance and a low coefficient of thermal expansion, and give high bonding force between polyimide film and metal film. A monomer of 4,4'-oxybis[N-(4-amino-2-alkoxyphenyl)benzamide] has a structure represented by the following formula 1, wherein R is CnH2n+1 and n is an integer of 1-12. A polyimide precursor composition comprises a reaction product prepared by a condensation reaction of a dianhydride compound and a diamine compound including 4,4'-oxybis[N-(4-amino-2-alkoxyphenyl)benzamide]. The dianhydride compound and diamine compound are used in a molar ratio of 95:100-105:100.

Description

Monomers for synthesizing polyimide, and polyimide precursor compositions and flexible metal foil laminates including the same {monomer for synthesizing polyimide, and polyimide precursor and flexible metal clad laminate including the same}

1 is a schematic cross-sectional view of a polyimide metal foil laminate.

※ Explanation of code about main part of drawing ※

11: polyimide film

12: metal film

The present invention relates to a monomer for polyimide synthesis, and a polyimide precursor composition and a flexible metal foil laminate including the same. More specifically, the present invention is to produce a polyimide metal foil laminate useful for a flexible printed circuit board (FPCB), a novel monomer having excellent flex resistance and adhesion among the monomers for making a polyimide precursor 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] and its application.

In general, polyimides having aromatics have been widely used in electrical wiring coatings and electrical insulation materials because of their high mechanical strength and high heat resistance compared to other polymer materials. In particular, recently, due to the development of the electronic industry and the tendency to reduce the weight of electronic products, It is widely used in various applications such as interlayer insulating films for module substrates, chip carrier tapes, flexible printed circuit boards, liquid crystal alignment films, and heat resistant adhesives.

In particular, flexible printed circuit boards are flexible printed circuit boards used to mount electrical components and semiconductors used in electronic products. In addition to mobile phones, cameras, flat panel displays, computers, video, DVDs, camcorders, satellite equipment, military equipment, etc. It is a core part that is widely used in medical equipment, etc.

Polyimide is a main raw material of a flexible metal foil laminate such as a flexible copper clad laminate (FCCL) used as a raw material of such a flexible printed circuit board. Polyimide substrates are used in the form of composites of aromatic polyimide films / sheets, metal films (eg copper films, aluminum films), or adhesives such as epoxy.

For example, as a method of manufacturing FCCL, the method of hardening | curing after apply | coating the polyamic acid which is a precursor of a polyimide on copper foil is known. By the way, since a curl generate | occur | produces in a polyimide at a process, it is necessary to manufacture the thermal expansion coefficient (CTE) of a polyimide like copper foil.

If there is a difference in coefficient of thermal expansion between the polyimide film and the metal film, tension will occur at the hard interface, causing the FCCL to decay and affect dimensional stability and planarity. Therefore, the difference in coefficient of thermal expansion between polyimide and metal should be reduced. To this end, when preparing a polyamic acid solution, there is a method of adjusting the molar ratio of diamine and dianhydride or adding an inorganic additive.

However, lowering the coefficient of thermal expansion lowers the flexibility of the polyimide copper foil laminate. In this regard, Japanese Patent Application Laid-open No. Hei 6-93537 introduces an amide derivative to prevent such a problem, but it is still required to develop a polyimide having a low coefficient of thermal expansion and an excellent bending resistance because of its poor flexibility.

The main object of the present invention is 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] which is a novel monomer having high flex resistance (4,4'-oxybis [N- (4- amino-2-alkoxyphenyl) benzamide]) and its application method.

Another object of the present invention is to provide high flex resistance, high adhesion between the polyimide film and the metal film while lowering the coefficient of thermal expansion (CTE) of 4,4'-oxybis [N]. -(4-amino-2-alkoxyphenyl) benzamide] and its application method.

It is still another object of the present invention to provide excellent properties with respect to planarity after curing and etching using the polyimide precursor composition containing 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide]. It is to provide a flexible metal foil laminate having the same.

Another object of the present invention is to apply a polyimide precursor composition comprising 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] onto a metal film / metal foil. It is to provide a flexible metal foil laminate which can improve flex resistance and planarity to efficiently perform circuit work.

In order to achieve the above and other purposes,

According to one aspect of the invention,

4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by the following formula (1) (4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] Is provided:

Formula 1

Wherein R is C _n H _{2n + 1} and n is an integer from 1 to 12.

According to another aspect of the present invention,

To include a reaction product by a condensation reaction of a diamine compound and a dianhydride compound containing 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by the formula (1) There is provided a polyimide precursor composition characterized by:

Formula 1

Wherein R is C _n H _{2n + 1} and n is an integer from 1 to 12.

Here, the dianhydride compound may be preferably a compound represented by the following formula (2):

Formula 2

Wherein A is;

It is selected from the group consisting of.

The diamine compound may also preferably further comprise 4,4'-diaminodiphenyl ether, phenylenediamine or mixtures thereof.

In this case, the dianhydride compound and the diamine compound may be preferably used in a molar ratio of 95: 100 to 105: 100.

On the other hand, the polyimide precursor composition may preferably have a solid content of 5 to 30% by weight.

According to another aspect of the present invention,

The flexible metal foil laminate is provided by applying the polyimide precursor composition to at least one surface of a conductive metal film and then curing the polyimide precursor composition.

Here, the conductive metal may be preferably selected from the group consisting of copper, silver, gold, platinum, palladium, nickel, iron, aluminum, molybdenum, tungsten, alloys and mixtures thereof.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by Formula 1, which is a monomer for synthesizing polyimide according to the present invention, may be synthesized according to the following method It is not specifically limited to this.

Amidation with, for example, 2-alkoxy-4-nitroaniline and 4,4'-oxybisbenzoyl chloride (4,4'-oxybis (benzoyl chloride)) as starting material Reaction gave 4,4'-oxybis [N- (4-nitro-2-alkoxyphenyl) benzamide] (4,4'-oxybis [N- (4-nitro-2-alkoxyphenyl) benzamide]) After this, it is possible to obtain a monomer represented by the formula (1) of the present invention through a nitro group reduction reaction.

In particular, the method for reducing the nitro group is not particularly limited as long as it is known in the art, and examples thereof include metal catalysts such as platinum, palladium, nickel, copper, iron, and zinc, and reducing agents such as hydrogen gas. And a method of using NaBH ₄ , LiAlH ₄ , and the like. In this case, the metal catalyst used may be either a metal precursor catalyst or a catalyst supported on a carrier such as carbon, alumina, silica, titania, zirconia, zeolite, or the like. In addition, the reduction reaction may be carried out in a batch or continuous reaction form.

According to the present invention, a polyimide film on a metal film using 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by Formula 1 as a monomer for polyimide synthesis A polyimide precursor composition for laminating the same is constituted.

In general, polyimide is not well dissolved in a solvent, so in order to produce a flexible metal foil laminate composed of a polyimide film / metal film, a polyamic acid solution, which is a polyimide precursor composition, must first be prepared. Polyamic acid solutions are generally prepared by condensation reaction by dissolving dianhydride compounds and diamine compounds in polar solvents.

In the present invention, a diamine compound containing 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by Chemical Formula 1 as an essential component is used as the diamine compound.

The diamine compound may include, in addition to the compound of Formula 1, diamine compounds generally used in the art as needed, for example, 4,4'-diaminodiphenyl ether, phenylenediamine, or a compound thereof. It may be, but is not particularly limited thereto.

Although the dianhydride compound used for the polyimide precursor composition of this invention is not specifically limited, Preferably, the compound represented by following formula (2) can be used.

Formula 2

Wherein A is;

It is selected from the group consisting of.

Here, the amount of the dianhydride compound and the diamine compound used is not particularly limited, but it is preferable to make the reaction in a 95: 100 to 105: 100 molar ratio.

In addition, the total amount of the diamine compound containing the above-mentioned dianhydride compound and 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] of Formula 1 can be adjusted according to the viscosity Preferably, the polyimide precursor composition is adjusted to have a solid content of 5 to 30% by weight.

The organic solvent usable in the present invention is not particularly limited and may be anything known in the art. As one example, polar solvents such as N-methylpyrrolidone, N, N'-dimethylacetamide, metacresol and the like can be used.

As described above, the dianhydride compound and the diamine compound are dissolved in a polar solvent and then reacted under the usual condensation reaction conditions to obtain a polyimide precursor composition, that is, a polyamic acid solution. The condensation reaction is preferably carried out in a nitrogen atmosphere, it can be carried out by increasing the temperature as necessary (for example, 50 ℃) to proceed at room temperature or to increase the reaction rate.

Hereinafter, a method of preparing a polyamic acid solution through a condensation reaction as shown in Scheme 1 using the compound of Formula 1 as a diamine compound and the compound of Formula 2 as a dianhydride compound will be described. It will be apparent to those skilled in the art that the method for preparing the polyimide precursor composition of the present invention is not particularly limited thereto as it is merely to more specifically describe the present invention.

Wherein A is;

It is selected from the group consisting of, R is C _n H _{2n + 1} , n is an integer of 1 to 12, m is a natural number of 10 to 500.

That is, 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by Formula 1 and dianhydride of Formula 2 are dissolved in the above-described organic solvent, and then, It condenses at the temperature of and the polyamic-acid solution which is a polyimide precursor is obtained.

The polyimide precursor composition of the present invention is a conductive film selected from the group consisting of film substrates made of conventional conductive metals, namely copper, silver, gold, platinum, palladium, nickel, iron, aluminum, molybdenum, tungsten, alloys and mixtures thereof The metal film 12 is applied onto the metal film substrate and thermally imidated by heating stepwise, for example, in a temperature range of about 80 to 400 ° C. according to curing methods known in the art. The polyimide film 11 may be laminated on the) to implement a polyimide flexible metal foil laminate.

In the following Examples and Comparative Examples, in order to illustrate the effects of the present invention, a novel monomer, 4,4'-diaminodiphenyl ether (ODA) and N- (4-amino-2-methoxyphenyl) benzamide alone After the polyamic acid solution was prepared using a mixture, or coated on a metal film and thermally imidized to form a flexible metal foil laminate in which the polyimide film was laminated.

However, this invention is not limited to the following example.

The symbols used in the following refer to the following compounds:

OBMA: 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide]

ODA: 4.4'-diaminodiphenyl ether

NBA: N- (4-amino-2-methoxyphenyl) benzamide

PDA: Phenylenediamine

PMDA: pyromellitic acid dianhydride

BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride

BTDA: Benzophenonetetracarboxylic acid dianhydride

DMAc: N, N-dimethylacetamide

NMP: N-methylpyrrolidone

<Example 1>

-Synthesis of 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide]

(1) Synthesis of 4,4'-oxybis (benzoyl chloride)

21.7 g (0.084 mol) of 4,4'-oxybis (benzoic acid) and NMP 130g were added to a 500 ml flask, and the mixture was stirred at room temperature. After cooling using an ice bath, 20.0 g (0.168 mol) of thionyl chloride was slowly added dropwise for 30 minutes, followed by stirring at room temperature for 3 hours.

(2) Synthesis of 4,4'-oxybis [N- (2-methoxy-4-nitrophenyl) benzamide]

A 2-liter 4-methoxy-4-nitroaniline, 28.3 g (0.168 mol) of NMP, 100 g of pyridine and 26.6 g of pyridine were added to a 1 L flask equipped with a mechanical stirring device. 160 ml of the 4,4'-oxybis (benzoyl chloride) solution obtained in (1) was added dropwise while keeping the internal temperature at 10 ° C or lower using an ice bath. All were added dropwise and stirred at room temperature for 3 hours. After the reaction was completed, 500 ml of distilled water was added and the product was filtered.

(3) Synthesis of 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide]

10 g (0.018 mol) of 4,4'-oxybis [N- (2-methoxy-4-nitrophenyl) benzamide] obtained in (2) in a 300 cc high-pressure batch reactor, 0.4 g of 5% Pd / C, dimethyla 190 g of cetamide (DMAc) was added thereto, and the mixture was stirred at 100 ° C. and 30 atmospheres of hydrogen for 5 hours to react. After the reaction, the catalyst was filtered off and crystallized in DMF to obtain 7.1 g of 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide].

Hereinafter, the polyimide film and polyimide which were produced by the 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide] of this invention in Examples 2-5 and Comparative Examples 1-5 The FCCL characteristics of the copper foil are compared with the case of the FCCL according to the prior art.

Since the novel monomer of this invention is a raw material of the polyimide used as an insulating material in an electrical circuit diagram, planarity (curl before and after etching) and bending resistance are important for reducing a circuit defective rate. In addition, the properties of the polyimide resin using 4,4'-oxybis [N- (4-amino-2-methoxyphenyl) benzamide] were measured by measuring the thermal constant coefficient (CTE) and elongation. Compared with resin.

The measurement items are as follows.

-Planarity: Comparison of curl characteristics of the polyimide copper foil laminate before and after etching

Curl properties are evaluated as follows:

1) The curl characteristic of the polyimide copper foil laminated body obtained by hardening is observed.

2) The polyimide copper foil laminate of 1) is cut into squares and 5 cm x 5 cm in size and etched in a FeCl ₃ solution for 30 minutes. The etched polyimide film pieces are washed with distilled water and dried at 80 to 100 ° C for 30 minutes. The curling properties of the dry polyimide film are observed.

Thermal expansion coefficient (CTE): TMA analysis

Flexibility: Japanese Industrial Standard (JIS) C 6471

             : Resistance to folding

Peeling strength: measuring adhesion between polyimide film and metal foil

 Japanese Industrial Standard (JIS) C 6471

             : Peeling strength of copper foil (Method B)

Elongation: IPC-TM-650, Method 2.4.19

<Example 2>

56.6 g of DMAc and 6.704 g of OBMA were added to the reaction vessel, and the mixture was stirred at room temperature at 300 rpm until a uniform diamine solution was formed. It is preferable to proceed with the reaction in a nitrogen atmosphere. PMDA 2.222g and BTDA 1.094g were added to the solution and the mixture was stirred at 300 rpm for 3 hours or more to prepare a high viscosity polyamic acid solution.

The solution was taken out of the reactor to allow sufficient time for bubbles to be removed, and then coated on copper foil. After the drying process for 1 hour from 80 ℃ to 185 ℃ and proceeded to 350 ℃ heat imidization. FCCL of the polyimide / copper film was obtained from the thus-coated polyamic acid.

The physical properties of the polyimide resin obtained in Example 2 were measured by the above measuring method.

The planarity of polyimide resin laminates is an important factor in post-processing and increases the accuracy of circuit boards. The curl after etching was measured by the method of confirming planarity. The FCCL obtained in Example 2 slightly curled in the polyimide direction, but there was no problem in use. After the etching, the resultant polyimide film was flat.

The coefficient of thermal expansion (CTE) was 26 ppm / 占 폚 and the flex resistance was 381 times. The adhesive strength between the copper foil and the polyimide of this example was 0.7 kg / cm.

And the polyimide resin laminated body was etched and only the polyimide film was left and the mechanical characteristic was measured. The elongation of the polyimide film having a thickness of about 20 μm was measured, and the mechanical strain was 6.2%.

In summary, the FCCL prepared in Example 2 has good flatness, bendability, adhesive strength, and elongation before and after etching, so that the flexible circuit board may be manufactured.

Comparative Example 1

In Example 2 an ODA mole fraction 100% diamine solution was used instead of OBMA and ODA instead. Other than that is the same as Example 2.

The physical properties of the polyimide resin using ODA relative to the novel monomers are as follows.

In the polyimide copper foil laminate obtained by curing, curls appeared strongly in the polyimide direction and curled in the opposite direction after etching. A clear difference in curl characteristics was shown when compared to Example 2. As a result of the CTE measurement, it can be inferred that curl was strong because it was 33 ppm / ° C. On the other hand, the flex resistance was relatively higher than that of Example 2, indicating 536 times.

The elongation of the polyimide film was 13.7%, which showed high mechanical strain and 0.8kg / cm of peeling strength, which showed similar adhesion.However, since the curls before and after etching appeared strongly, post-processing of the substrate was difficult and the accuracy of the circuit was reduced. .

<Example 3>

68.1 g of DMAc, 1.378 g of PDA and 2.118 g of OBMA were added to the reaction vessel, and the mixture was stirred at room temperature at 300 rpm until a uniform diamine solution was formed. It is preferable to proceed with the reaction in a nitrogen atmosphere. 5.050 g of BPDA was added to the solution and the mixture was stirred at 300 rpm for at least 3 hours to prepare a high viscosity polyamic acid solution. Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

Physical properties of the polyimide resin copper foil laminate obtained in Example 3 were measured in the same manner as in Example 2.

The polyimide copper foil laminated body obtained in Example 3 did not generate curl. The polyimide film also showed perfect planarity after etching. No curling can be observed at all, which is expected because the copper and CTEs are similar, with a CTE of 11 ppm / ° C. If the polyimide film has excellent planarity, post-working becomes flat and the accuracy of the circuit increases.

It showed high bending resistance of 761 times and the peeling strength was also high as 0.9kg / cm, which showed very excellent physical properties. It is a material of flexible copper foil laminate that is not only high in accuracy of circuit but also excellent in life of circuit board, and can be used directly. The mechanical strain is also low at 4.6%, which is stable.

Comparative Example 2

In Example 3, an ODA 25%, PDA 75% mole fraction diamine solution was used in place of ODA without using OBMA. Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

The physical properties of the polyimide resin using ODA relative to the novel monomers are as follows.

The polyimide film before and after the etching showed planarity. As a result of the CTE measurement, it was similar to the copper foil CTE at 15 ppm / ° C. Compared with Example 3, the CTE exhibited planarity because of its similarity to copper foil, but the flex resistance was reduced by 60% compared with Example 3 in 299 cycles.

The elongation of the polyimide film is 12.1%, the mechanical strain is high, and the adhesion is 0.7 kg / cm, which is lower than that of Example 3.

Since it shows a CTE similar to copper foil, the planarity is excellent in Example 3 and Comparative Example 2, but the bending resistance, the adhesion between copper foil / polyimide, and the mechanical properties are excellent in Example 3, so that the new monomer OBMA has great utility in actual production. Has

Comparative Example 3

In Example 3, an NBA 25%, PDA 75% mole fraction of diamine solution was used in place of NBA without using OBMA.

Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

The physical properties of the polyimide resin using NBA compared to the new monomer are as follows.

In Example 3, curling did not appear at all before and after etching, but the polyimide film of Comparative Example 3 before etching was weakly curled. And after etching, the curls appeared stronger. As a result of the CTE measurement, it was much lower than the copper foil CTE at 5 ppm / ° C. Because of the low CTE, the flex resistance was measured 169 times, which was reduced by 80% compared to Example 3.

The polyimide film elongation of Comparative Example 3 was 5.3%, and the mechanical strain was similar, but the adhesion was very low, 0.5 kg / cm.

In Comparative Examples 2-3, using ODA or NBA instead of the new monomer OBMA, the planar-curl characteristics for the accuracy and workability of the circuit are similar, but the flex resistance is reduced by 60 to 80%, and the adhesion is also up to 45% in Comparative Example 3. Decreased.

<Example 4>

44.1 g of DMAc and 4.774 g of OBMA were added to the reaction vessel, and the mixture was stirred at room temperature at 300 rpm until a uniform diamine solution was formed. It is preferable to proceed with the reaction in a nitrogen atmosphere. 3.000 g of BPDA was added to the solution and the mixture was stirred at 300 rpm for at least 3 hours to prepare a high viscosity polyamic acid solution. Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

The physical properties of the polyimide resin obtained in Example 4 were measured by the above method.

The FCCL of Example 4 showed curl in the polyimide direction, but after etching, the curl of the polyimide film was reduced, resulting in weak curl. As a result of the CTE measurement, it was similar to the CTE of copper foil at 21 ppm / ° C.

It showed 337 times of flex resistance and relatively high adhesive strength of 0.8kg / cm, indicating good physical properties. And the mechanical strain is as low as 3.5%.

<Comparative Example 4>

NBA was used instead of OBMA of Example 4 to use a diamine solution of 100% NBA mole fraction. Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

The polyimide resin physical properties of Comparative Example 4 are as follows.

After curing, strong curls could be seen and after etching the polyimide film showed a relatively flat curl with a slight decrease in curl. As a result of the CTE measurement, it was similar to the copper foil CTE at 14 ppm / ° C, and the flex resistance was 221 times, which was reduced by 100 times or more compared with Example 4. The polyimide film elongation is 4.8%, the mechanical strain is similar and the adhesion is very low, 0.4kg / cm.

In comparison with Example 4, FCCL of Comparative Example 4 has a 50% reduction in adhesion and 100 times or less in adhesion, so that only the curl characteristics are similar.

<Example 5>

126.0 g of DMAc, 1.836 g of ODA, and 4.571 g of OBMA were added to the reaction vessel, and the mixture was stirred at room temperature at 300 rpm until a uniform diamine solution was formed. It is preferable to react in a nitrogen atmosphere. 4.040 g of PMDA was added to the solution and the mixture was stirred at 300 rpm for at least 3 hours to prepare a polyamic acid solution.

Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

Physical properties of the polyimide resin were measured by the above method.

Weak curls appeared in the polyimide direction before etching and weak curls appeared in the opposite direction after etching. In addition, the CTE was 32ppm / ℃, and the flex resistance measurement resulted in 528 excellent flex resistance and the adhesion was very high as 1.2kg / cm, which showed good physical properties in terms of the life of the substrate. The mechanical strain is high at 8.8%.

Comparative Example 5

NBA was used in place of the OBMA of Example 5 to use an ODA 50%, NBA 50% mole fraction diamine solution.

Other experimental procedures were the same as in Example 2 to obtain a polyimide resin laminate.

Curing did not appear before etching, but after etching, the curl of the polyimide was so severe that the film itself dried. As a result of CTE measurement, it was found to be 12ppm / ° C, which showed a similar CTE to copper foil, but the curl characteristics were very poor. In contrast to Example 5, the CTE of the polyimide film was small from the copper foil, but curled strongly.

Flexural resistance was 66% compared to Example 5 in 349 cycles, and the adhesive force was 0.6kg / cm, which was reduced by half. In comparison, the mechanical strain was 11.1%, which is higher than that of Example 5.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the polyimide monomer according to the present invention, and the polyimide precursor composition and the flexible metal foil laminate including the same are not limited thereto. It is apparent that modifications and improvements can be made by those skilled in the art within the technical idea of the present invention.

Advantages of the polyimide resin copper foil laminate using the novel monomer 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] according to the embodiment are as follows.

In comparison to ODA or NBA, the curl properties of polyimide films using novel monomers were improved. As mentioned earlier, the planarity of the polyimide resin laminate is an important factor in the post-production process. Even in the composition where curl occurs due to the use of ODA or NBA, the CTE is lowered and replaced with copper CTE when it is replaced with 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide]. Because of the reduction, the flatness of the film is improved. In Comparative Example 5, although the CTE was similar to the copper foil, the curl property of the film using the new monomer was excellent. Therefore, when using a new monomer, there is an advantage that the post-fabrication work is convenient and the accuracy of the circuit board is increased.

As is known, ODA-containing polyimide films exhibit excellent adhesion to copper foil. However, even when the new monomer was used, it had excellent adhesion similar to ODA and showed a maximum of 1.2 kg / cm. In addition, it shows superior adhesiveness compared to polyimide resin compared to NBA, showing the superiority of the novel monomer.

In the case of ODA and 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide], a compound connected by an ether bond has a structural advantage in terms of flex resistance. However, when ODA is used, CTE is increased and the curling properties are deteriorated. Therefore, a large amount cannot be used, and the NBA has a low CTE, so it is possible to control the curling properties, but there are disadvantages in that physical properties such as adhesion and flex resistance are poor.

However, using the OBMA of the present invention compared to ODA in the same composition, the flex resistance was similar or increased. Polyimide resin using OBMA compared to NBA had better adhesion and curling properties as well as excellent flex resistance. This is a property directly related to the life of the circuit board, and using OBMA, it was possible to produce a polyimide laminate having excellent curling properties and adhesive properties and excellent durability.

When Examples 2-5 are compared with Comparative Examples 1-5, elongation of OBMA polyimide shows 9% or less. This is the numerical value which measured about 20 micrometers polyimide film, and there was little mechanical strain of the polyimide film copper foil laminated body which used OBMA compared with ODA or NBA.

In summary, the novel monomer OBMA of the present invention is excellent in planarity because the curling resistance is lower than that of ODA or NBA because the coefficient of thermal expansion is lower than that of ODA and the coefficient of thermal expansion is low. In addition, OBMA polyimide resin exhibits adhesion similar to or greater than that of ODA, which is known to have high peel strength, and has low mechanical strain. Therefore, the polyimide resin copper foil laminate using OBMA has the advantage of increasing the work efficiency of the circuit board and increasing the life of the circuit board.

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

Claims (8)

4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by the following formula (1) (4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] ): Formula 1

Wherein R is C _n H _{2n + 1} and n is an integer from 1 to 12. To include a reaction product by a condensation reaction of a diamine compound and a dianhydride compound containing 4,4'-oxybis [N- (4-amino-2-alkoxyphenyl) benzamide] represented by the formula (1) Characterized polyimide precursor composition: Formula 1

Wherein R is C _n H _{2n + 1} and n is an integer from 1 to 12. The polyimide precursor composition according to claim 2, wherein the dianhydride compound is a compound represented by the following Chemical Formula 2: Formula 2

Wherein A is;

Selected from the group consisting of: The polyimide precursor composition of claim 2, wherein the diamine compound further comprises 4,4′-diaminodiphenyl ether, phenylenediamine, or mixtures thereof. The polyimide precursor composition according to claim 2, wherein the dianhydride compound and the diamine compound are used in a molar ratio of 95: 100 to 105: 100. The polyimide precursor composition of claim 2, wherein the polyimide precursor composition has a solids content of 5 to 30% by weight. A flexible metal foil laminate, wherein the polyimide precursor composition according to any one of claims 2 to 6 is applied to at least one surface of a conductive metal film and then cured. The flexible metal foil laminate according to claim 7, wherein the conductive metal is selected from the group consisting of copper, silver, gold, platinum, palladium, nickel, iron, aluminum, molybdenum, tungsten, alloys and mixtures thereof.

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