WO2012081763A1

WO2012081763A1 - Polyimide film

Info

Publication number: WO2012081763A1
Application number: PCT/KR2010/009622
Authority: WO
Inventors: 이길남; 원동영; 안찬재; 김성원; 명범영
Original assignee: 에스케이씨코오롱피아이주식회사
Priority date: 2010-12-16
Filing date: 2010-12-31
Publication date: 2012-06-21
Also published as: KR20120067645A; KR101558621B1

Abstract

The present invention relates to a polyimide film, and relates to a polyimide film which has outstanding dimensional stability and tear strength, and which is used as a base film for products where high reliability is required.

Description

Polyimide film

The present invention relates to a polyimide film excellent in dimensional stability and tear strength.

Polyimide films are widely used in electrical / electronic materials, aerospace / aviation and telecommunications because of their excellent mechanical and thermal dimensional stability and chemical stability.

In particular, the polyimide film has been widely used as a flexible printed circuit board material having a fine pattern, for example, a base film such as TAB or COF due to light and small size of the component.

TAB or COF technology is a kind of technology for sealing IC chip or LSI chip. Specifically, TAB or COF technology is used to make a conductive pattern on a flexible tape and seal it by mounting the chip on it. It is advantageous to reduce the thickness of the product.

In order to use a polyimide film as a base film for TAB or COF, high dimensional stability is required. This is because a dimensional change may occur due to heat shrinkage or a dimensional change may occur due to residual stress after an etching process in a TAB or COF manufacturing process for bonding a polyimide film in a heated state or a cooling process after a sputtering process. As a result of the dimensional change, a position error may occur during the process of bonding the IC or LSI chip to the TAB or COF.

In addition, as the polyimide film undergoes a high temperature treatment process, expansion occurs due to heat, and a coefficient of thermal expansion (CTE) is measured. If the coefficient of thermal expansion is large, the polyimide film shrinks more than the semiconductor while cooling after the semiconductor bonding at a high temperature, which is not good to stress the bonding site.

The present invention is to provide a polyimide film with improved dimensional stability and tear strength by the network structure of the polymer.

Polyimide film according to an embodiment of the present invention is an aromatic tetracarboxylic dianhydride component containing biphenyltetracarboxylic dianhydride or a functional derivative thereof, p-phenylenediamine, diaminodiphenyl ether and Obtained by imidizing a polyamic acid comprising an aromatic diamine component comprising diamino benzoic acid; Dimensional stability, measured according to IPC ™ 650 2.2.4A, is 0.02% or less; Tear strength measured according to ASTM D 1004 standard may be more than 3.0kgf.

In the above embodiment, the aromatic diamine component may include at least 3 mol% of diamine benzoic acid in the total aromatic diamine component.

In the above embodiment, the biphenyl tetracarboxylic dianhydride or a functional derivative thereof may be 90 mol% or more of the total aromatic tetracarboxylic dianhydride component.

100 mole% of an aromatic tetracarboxylic dianhydride component comprising biphenyltetracarboxylic dianhydride; It can be obtained by imidizing the polyamic acid which becomes 100 mol% of 55-75 mol% of p-phenylenediamine, 20-40 mol% of diamino phenyl ether, and 3-5 mol% of diamine benzoic acid.

In the above embodiment, the imidization may be accompanied by chemical conversion by a conversion agent comprising an imidization catalyst and a dehydrating agent.

The present invention will be described in more detail as follows.

The present invention provides an aromatic tetracarboxylic dianhydride component comprising a biphenyltetracarboxylic dianhydride or a functional derivative thereof, and an aromatic diamine component containing p-phenylenediamine, diaminodiphenylether and diamino benzoic acid. It relates to the polyimide film obtained by imidating the polyamic acid derived from it, Especially a dimensional stability is 0.02% or less; It relates to a polyimide film having a tear strength of 3.0 kgf or more.

Here, the dimensional stability is performed according to IPC TM 650 2.2.4A, and after 2 hours at the temperature of 200 ℃ to measure the MD (Mechanical Direction) / TD (Transverse Direction) dimensional change rate, the dimensional change rate is a three-dimensional measuring equipment Measure

In addition, the tear strength is in accordance with the ASTM D 1004 standard and measured in the MD / TD direction. The cross head speed is 51mm / min.

In general, the polyimide film is subjected to a wet process and a high temperature process in order to use a base film for TAB and COF. In this process, the polyimide film may have a minute dimensional change due to moisture, heat, etc. In the present invention, it is to provide a polyimide film with improved dimensional stability and tear strength by strengthening the interpolymer network.

Thus, in one embodiment of the present invention provides a polyimide film having a tear strength of 3.5 kgf or more, while the dimensional stability defined as described above is 0.02% or less.

When the polyimide film according to one embodiment of the present invention is applied to a flexible circuit board, particularly a base film for TAB or COF, which is a semiconductor mounted flexible circuit board, dimensional change or separation of an adhesive layer in a severe flexible circuit board manufacturing process, etc. May not occur.

In this regard, the polyimide film according to one embodiment of the present invention may have a moisture absorption rate of 1.4% or less in particular.

At this time, the moisture absorption is measured by cutting a portion of the film in a chamber (Chamber) at 100% RH (relative humidity) atmosphere for 48 hours and then analyzing it by using a thermal gravimetric analysis. The temperature can be calculated by analyzing the change in weight by heating the temperature from 35 ° C to 250 ° C at 10 ° C / min.

During the manufacturing process of flexible circuit board using polyimide film, if the film absorbs moisture during the wet process, volume expansion occurs, distorting the dimensions of the flexible circuit board, and due to vapor evaporated in high temperature process This may cause delamination.

In this regard, the polyimide film according to the embodiment of the present invention may preferably have a moisture absorption of 1.3% or less.

The method for satisfying the dimensional stability and tear strength within the above range is not limited, but the method contemplated by the present invention is biphenyltetracar as the aromatic tetracarboxylic dianhydride component used to prepare the polyamic acid. A method containing an acid dianhydride or a functional derivative thereof, and containing p-phenylenediamine, diaminophenyl ether and diamino benzoic acid as an aromatic diamine component is mentioned.

Particularly preferably, the aromatic diamine component contains at least 3 mol% of diamine benzoic acid in the total aromatic diamine component, thereby improving dimensional stability and tear strength by strengthening the network structure of the polymer while allowing viscosity control.

Also preferably, the aromatic tetracarboxylic dianhydride component includes biphenyltetracarboxylic dianhydride or a functional derivative thereof in an amount of 90 mol% or more in the total aromatic tetracarboxylic dianhydride component to improve chemical resistance. You can.

In view of satisfying the above dimensional stability and tear strength, the most preferred polyimide film is 100 mol% of an aromatic tetracarboxylic dianhydride component comprising biphenyltetracarboxylic dianhydride; It may be obtained by imidizing a polyamic acid consisting of 100 mol% of an aromatic diamine component comprising 55 to 75 mol% of p-phenylenediamine, 20 to 40 mol% of diaminodiphenyl ether, and 3 to 5 mol% of diamino benzoic acid. .

Another method that can be considered to satisfy the above dimensional stability and tear strength is that imidization may involve chemical conversion by a conversion agent comprising an imidization catalyst and a dehydrating agent.

In order to facilitate understanding of the preparation of the polyimide film for achieving the present invention, the composition and the film forming method are specifically described below, but are not limited thereto.

[Aromatic Tetracarboxylic Anhydride]

The aromatic tetracarboxylic dianhydride that can be used in the present invention is biphenyltetracarboxylic dianhydride or functional derivatives thereof, such as 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, pyromelli Benzophenonetetracarboxylic dianhydride or its functional derivative, such as 3,3 ', 4,4'-benzophenonetetracarboxylic anhydride or p-phenylene-bis trimellis thereof Although an acid dianhydride etc. can be used, it is preferable to use biphenyl tetracarboxylic dianhydride in 90 mol% or more of all aromatic tetracarboxylic dianhydride as mentioned above.

A polyimide film containing an excess of biphenyltetracarboxylic dianhydride units has a high modulus of elasticity, low moisture absorption and excellent chemical resistance.

[Aromatic Diamine Component]

Diamines usable in the present invention include p-phenylene diamine, diaminophenyl ethers such as 4,4'-diaminophenyl ether, 3,4-diaminophenyl ether, 2,4-diaminophenyl ether, And diamino benzoic acid such as 3,5-diamino benzoic acid.

Preferably the proportion of p-phenylene diamine in the total diamine is at least 55 mol%, more preferably 55 to 75 mol% in the total aromatic diamine component. p-phenylene diamine is a monomer having a linearity compared to diamino phenyl ether serves to lower the coefficient of thermal expansion of the film (Coefficient of thermal expansion). On the other hand, if the content of p-phenylene diamine is high, the flexibility of the film may be reduced and the film forming ability may be lost.

In this aspect, the content of diaminophenyl ether used in combination may be 40 mol% or less, preferably 20 to 40 mol% of the total aromatic diamine components.

In addition, the content of diamino benzoic acid used in combination may be 3 mol% or more, preferably 3 to 5 mol% in the total aromatic diamine component. Diamino benzoic acid can improve the physical properties such as dimensional stability, tear strength by strengthening the intermolecular network structure at the same time to control the viscosity.

[Polyimide Film Film Forming Method]

In general, the method for forming a polyimide film is not particularly noticeable to those skilled in the art, but provides an example; First, the aromatic tetracarboxylic dianhydride and the aromatic diamine component are reacted with an organic solvent to obtain a polyamic acid solution. In this case, the solvent is generally preferably an aprotic polar solvent (Aprotic solvent) as the amide solvent, for example, N, N'- dimethylformamide, N, N'- dimethylacetamide, N-methyl- Pyrrolidone etc. can be mentioned and can also be used in combination of 2 types as needed.

The input form of the monomer may be added in the form of powder, lump, and solution. In the initial stage of the reaction, the monomer may be added in the form of powder, and the reaction may be performed in the form of a solution to control the polymerization viscosity.

The weight of the monomer added in the total polyamic acid solution in the state in which the equimolar amount of the aromatic diamine component and the aromatic tetracarboxylic dianhydride is added is called solid content, and the solid content is between 10-30%, preferably between 14-20% The polymerization may be performed in the range of. In particular, it is preferable to proceed block polymerization.

In addition, the order of monomer addition may be controlled so that the polyamic acid as described above contains a large amount of a molecular chain whose terminal is an amine.

On the other hand, a filler may be added to the polyimide film to improve various properties such as sliding properties, thermal conductivity, conductivity, and corona resistance. Although the type of filler may not be limited, preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like.

The particle size of the filler depends on the thickness or type of the film and may be a modified surface of the filler. 0.1-100 micrometers is preferable and, as for the average particle diameter of a filler, 0.1-3 micrometers is more preferable.

The addition amount of the filler is also not particularly limited and may vary depending on the film to be modified, the type and particle size of the particles, the particle surface, and the like. The addition amount of the filler is preferably used in the range of 0.04 to 3% based on the solids content of the polymerized polyamic acid solution. If the amount of the filler is used in the above range, the physical properties of the polyimide film may be impaired. If the filler is used in the range below, the modification effect is hardly seen.

The dosing method can be added at the beginning of the reactants or after the reaction is over. Alternatively, in order to prevent contamination of the reactor, it may be added in a catalyst mixing step, and the addition method and timing are not particularly limited.

The obtained polyamic acid solution may be applied to the support by mixing with a converting agent, preferably an imidization catalyst and a dehydrating agent. Examples of the catalyst used may include tertiary amines, and anhydrides may be cited as the dehydrating agent. Examples of anhydrous acid include acetic anhydride, and tertiary amines include isoquinoline, β-picolin, pyridine and the like.

The amount of anhydrous acid can be calculated by the molar ratio of o-carboxylic amide functional group in the polyamic acid solution, and it is preferable to use 1.0-5.0 molar ratio.

The amount of tertiary amine can be calculated by the molar ratio of o-carboxylic amide groups in the polyamic acid solution, and it is appropriate to add between 0.2 and 3.0 molar ratios.

The conversion agent may be used in the form of a mixture of anhydrous acid / amines or anhydrous acid / amine / solvent mixture.

The film applied on the support is gelled on the support by dry air and heat treatment. The gelation temperature of the coated film is preferably 100 ~ 250 ℃ and may be used as a support, such as glass plate, aluminum foil, circulating stainless belt or stainless drum, but is not limited thereto.

The treatment time required for gelation depends on the temperature, the type of the support, the amount of the polyamic acid solution applied, and the mixing conditions of the conversion agent, and is not limited to a certain time, but is preferably performed within a range of 5 minutes to 30 minutes. It is good.

The gelled film is separated from the support and heat treated to complete drying and imidization. Heat treatment temperature is between 100 ~ 600 ℃ and treatment time is between 1 ~ 30 minutes. The gelled film proceeds by being fixed to a support during heat treatment. Gel film can be fixed using a pin type frame or a clip type.

The residual volatile content of the film after heat treatment is 5% or less and preferably 3% or less.

After the heat treatment, the film is heat treated under a constant tension to remove residual stress in the film. Since the tension and temperature conditions are correlated with each other, the tension conditions may vary with temperature. Temperature is preferably maintained between 100 ~ 600 ℃, the tension is preferably 50N or less, the time is preferably maintained for 1 minute to 1 hour.

Hereinafter, the present invention will be described in detail with reference to the following Examples, the present invention is not limited by the Examples.

실시예 1Example 1

820 g of N, N'-dimethylformamide (DMF) was added to the 2L jacket reactor as a solvent. The temperature was 30 degreeC, 20.5 g of p-phenylenediamine (p-PDA), and biphenyl tetracarboxylic dianhydride (BPDA) were added. After stirring for about 30 minutes to confirm that the reaction was completed by changing the temperature inside the reactor was added diaminophenyl ether (ODA). After completion of the reaction, p-phenylenediamine (p-PDA) was added. After the addition, block polymerization was carried out for 1 hour while maintaining the temperature at 30 ℃.

Then, diamino benzoic acid (DABA) solution was added and stirred. In this case, the diamino benzoic acid solution was prepared at 5% concentration using DMF as a solvent.

The completed polyamic acid solution had a solid content of 15 wt% and a viscosity of 2,000 poise. The molar ratio of the injected monomer is BPDA 100%, ODA 35%, PDA 62%, DABA 3%.

100 g of this polyamic acid solution and 30 g of a conversion pharmaceutical solution (5.9 g of isoquinoline, 14 g of anhydrous acetic acid, 10.1 g of DMF) were uniformly stirred, applied to a stainless plate, cast at 250 μm, dried for 5 minutes with 150 ° C. hot air The film was peeled off the stainless plate and pinned to the frame.

The film on which the film was fixed was placed in a vacuum oven, heated slowly from 100 ° C. to 350 ° C. for 30 minutes, and then slowly cooled to separate the film from the frame. The thickness of the film finally obtained is 38 micrometers.

실시예 2 내지 실시예 6Examples 2-6

The polyimide film was prepared in the same manner as in Example 1, except that the polyimide film was prepared by varying the monomer composition ratio as shown in Table 1 during the polyamic acid polymerization.

실시예 7Example 7

850 g of N, N'-dimethylformamide (DMF) was added to the 2 L jacket reactor as a solvent. The temperature was 35 degreeC, 20.6g of p-phenylenediamine (p-PDA), biphenyl tetracarboxylic dianhydride (BPDA), and pyromellitic dianhydride (PMDA) were added. After stirring for about 30 minutes to confirm that the reaction was completed by changing the temperature inside the reactor was added diaminophenyl ether (ODA). After completion of the reaction, p-phenylenediamine (p-PDA) was added. After the addition, block polymerization was carried out for 2 hours while maintaining the temperature at 40 ℃.

The completed polyamic acid solution had a solid content of 15 wt% and a viscosity of 1,800 poise. The molar ratio of the injected monomer is 95 mol% BPDA, 5 mol% PMDA, 35 mol% ODA, 62 mol% PDA, and 3 mol% DABA.

The film on which the film was fixed was placed in a vacuum oven, heated slowly from 100 ° C. to 350 ° C. for 30 minutes, and then slowly cooled to separate the film from the frame.

비교예 1Comparative Example 1

A polyimide film was prepared in the same manner as in Example 1, except that paraphenylenediamine (PPD) was used instead of diamino benzoic acid (DABA) in polyamic acid polymerization.

비교예 2Comparative Example 2

830 g of N, N'-dimethylformamide (DMF) was added to the 2L jacket reactor as a solvent. The temperature was set to 30 ° C., and 23.1 g of p-phenylenediamine (p-PDA) and 24.2 g of diaminophenyl ether (ODA) were added. Then, the resultant was dissolved. Biphenyl-tetracarboxylic dianhydride (BPDA) 101.6 g was added. After stirring for about 30 minutes to confirm that the reaction was completed by the change in the temperature inside the reactor, the polymerization was stirred for 1 hour while maintaining the temperature at 30 ℃.

Thereafter, 22.4 g of a paraphenylenediamine (PPD) solution was added to the mixture, followed by stirring. In this case, the paraphenylenediamine (PPD) solution was prepared in 5% concentration using DMF as a solvent.

The reaction solution of the polyamic acid has a solid content of 15 wt% and a viscosity of 1800 poise. The molar ratio of the injected monomer is 100% BPDA, 35% ODA, 65% PDA.

The polyamic acid solution was applied to a stainless plate, cast at 250 μm, dried for 10 minutes with hot air at 120 ° C., and the film was peeled off from the stainless plate to fix the pin to the frame.

For the films prepared in Examples and Comparative Examples, the tensile modulus, linear expansion coefficient and tear strength were measured as follows, and the results are shown in Table 2.

(1) Tensile modulus

Tensile modulus was averaged by testing three times in accordance with ASTM D 882 using a standard instron testing apparatus.

(2) coefficient of linear expansion

A portion of the finished film was cut into a width of 4 mm and a width of 30 mm, and the coefficient of thermal expansion was measured using a TA company thermal mechanical apparatus Q400. The sample was hooked to a quartz hook and subjected to a force of 0.010 N and then heated at 10 ° C./min from 30 ° C. to 420 ° C. in a nitrogen atmosphere. The coefficient of thermal expansion was obtained within the range of 50 ° C to 200 ° C.

(3) tear strength

Tear strength was measured by ASTM D 1004 method.

Table 1

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7	Comparative Example 1	Comparative Example 2
BPDA	100	100	100	100	100	100	95	100	100
PMDA	-	-	-	-	-	-	5	-	-
PDA	62	67	69	72	65	70	62	65	65
ODA	35	30	28	25	30	25	35	35	35
DABA	3	3	3	3	5	5	3	-	-

TABLE 2

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7	Comparative Example 1	Comparative Example 2
Tensile Modulus (GPa)	5.4	5.7	6.0	6.2	5.5	6.2	5.5	5.4	5.1
Coefficient of linear expansion (ppm /)	14	13	10	9	14	9	14	14	18
Tear strength (kgf)	3.0	3.1	3.0	3.1	3.5	3.2	3.1	2.8	2.7

From the results of Table 2, it can be seen that the polyimide films obtained in Examples 1 to 7 have excellent tensile modulus, low linear expansion coefficient, and excellent tear strength.

On the other hand, the polyimide film obtained by Comparative Examples 1 to 2 was found to have a lower tensile modulus and tear strength and a higher coefficient of linear expansion than the polyimide film obtained by Examples 1 to 7.

Claims

Aromatic tetracarboxylic dianhydride component containing biphenyl tetracarboxylic dianhydride or its functional derivative, and polya which consists of aromatic diamine component containing p-phenylenediamine, diamino diphenyl ether, and diamino benzoic acid. Obtained by imidizing the mic acid;

Dimensional stability, measured according to IPC ™ 650 2.2.4A, is 0.02% or less;

Polyimide film with a tear strength of at least 3.0 kgf measured according to ASTM D 1004 specifications.
The polyimide film of claim 1, wherein the aromatic diamine component comprises at least 3 mol% of diamine benzoic acid in the total aromatic diamine component.
The polyimide film according to claim 1 or 2, comprising biphenyltetracarboxylic dianhydride or a functional derivative thereof in an amount of 90 mol% or more in the total aromatic tetracarboxylic dianhydride component.
100 mol% of an aromatic tetracarboxylic dianhydride component according to claim 1, comprising biphenyltetracarboxylic dianhydride; Polyimide obtained by imidating a polyamic acid consisting of 100 mol% of an aromatic diamine component comprising 55 to 75 mol% of p-phenylenediamine, 20 to 40 mol% of diaminophenyl ether, and 3 to 5 mol% of diamine benzoic acid. Mid film.
The polyimide film of claim 1, wherein the imidation involves chemical conversion by a conversion agent comprising an imidization catalyst and a dehydrating agent.