JP5362752B2 - Polyamic acid composition, polyimide, polyimide film and method for producing them - Google Patents

Description

  The present invention relates to a polyamic acid composition using a specific diamine component and a specific tetracarboxylic acid component in a specific ratio, and a polyimide obtained by curing it.

  Polyimide composition obtained by condensation polymerization and curing of aromatic tetracarboxylic dianhydride and aromatic diamine, and in particular polyimide film is excellent in electrical insulation and heat resistance. In the following, it is widely used in applications of electronic substrate materials such as FPC). FPC is manufactured by bonding a polyimide film and a copper foil with an adhesive such as an epoxy resin to produce a copper-clad laminate (hereinafter referred to as CCL) and applying a circuit to the copper foil. Recently, as electronic devices are becoming thinner, smaller, finer, and more advanced, there is an increasing demand for high workability and high precision of substrate materials. There are demands for stability, low thermal expansion, low water absorption, and the like. As means for improving the characteristics of such polyimide, there are cases where the components of polyimide monomers and their arrangement (random, block, etc.) are controlled, and various studies have been made so far.

  FPC is manufactured by bonding a polyimide film and a copper foil with an adhesive such as an epoxy resin to produce a CCL, and applying an electronic circuit to the copper foil by etching. In recent years, a chip-on-film (hereinafter referred to as COF) system in which an IC chip or the like is directly mounted on an FPC via a gold bump or the like is often used due to the demand for fine pitch electronic circuits. In the COF method, when an IC chip is mounted, there is a processing step at a high temperature, such as directly crimping to CCL at a high temperature. If the coefficient of thermal expansion of the polyimide film in the high temperature range is different from that of the copper foil, there arises a problem that wrinkles or curls occur in the CCL. Moreover, when Tg of a polyimide film is low, there exists a problem which a polyimide film softens at the time of mounting, and a circuit and an IC chip sink. For this reason, in COF applications involving IC chip mounting, the polyimide film is required to have a thermal expansion coefficient equivalent to that of a copper foil even in a high temperature region, and to have a high Tg and not be softened during high temperature pressure bonding. However, pyromellitic dianhydride (hereinafter, pyromellitic acid or its anhydride may be abbreviated as PMDA) and 4,4′-diaminodiphenyl ether (hereinafter, abbreviated as ODA), which are existing polyimide films. Or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter, the carboxylic acid or its anhydride may be abbreviated as BPDA) and paraphenylenediamine (hereinafter abbreviated as PDA). In the two-component system consisting of a combination with the copper foil, there is a problem that the coefficient of thermal expansion in the high temperature range is too large or too small compared to the copper foil. In the case of ternary or quaternary multi-component systems that combine them, the coefficient of thermal expansion can be controlled by adjusting the monomer ratio, but if there is a flexible skeleton such as BPDA-ODA, the Tg of the polyimide film There is a problem that decreases.

For example, Patent Document 1 describes that a varnish for producing an enameled wire was obtained from a polyamic acid composition containing a block copolymer part of ODA-BPDA or a block copolymer part of ODA-PMDA.
Patent Document 2 describes a method for producing a polyimide film by mixing and polymerizing PMDA, ODA, BPDA and PDA as a combination of monomer components to obtain a polyamic acid composition.

Patent Document 3 describes that a polyimide copolymer film is obtained from a polyamic acid copolymer solution containing a block copolymer portion of ODA-PMDA and a block copolymer portion of ODA-dimethylbenzidine.
Patent Document 4 describes that a polyamic acid of PDA-BPDA and a polyamic acid of ODA-PMDA are obtained and heated to produce polyimide.

Patent Document 5 describes a polyamic acid having a block copolymerized portion of PDA-PMDA, a polyamic acid having a block copolymerized portion of ODA-BPDA, and a polyamic acid composition obtained by polymerizing PMDA thereon.
In Patent Document 6, a polyimide film was obtained from a polyamic acid mixture obtained by further polymerizing PMDA in a polyamic acid composition having a block copolymerization portion of PDA-PMDA and a polyamic acid composition having a block copolymerization portion of ODA-BPDA. It is described.

Patent Documents 1, 2, 3, and 5 do not describe polyamic acid having a PDA-BPDA block copolymer moiety. On the other hand, in a composition having a polyamic acid having a PDA-PMDA block copolymer moiety, the Tg of the resulting polyamide may be reduced, resulting in poor heat resistance.
In Patent Document 2, since PDA, ODA, BPDA, and PMDA are mixed and polymerized, there is a problem that the heat resistance is lowered and the molecular weight is not so high.
In Patent Document 4, a mixture of polyamic acid of PDA-BPDA and polyamic acid of ODA-PMDA is described, and there is no description of a copolymer. In addition, only examples in which all the components of the monomer are equimolar are described, and the obtained polyimide film is described as having a fine concave structure formed on the surface, and characteristics such as heat resistance are unknown. is there. Since the polyamic acid of PDA-BPDA and the polyamic acid of ODA-PMDA take several days to mix at room temperature, uniform mixing is difficult, and even if they can be mixed, there is a problem that the molecular weight decreases.
In Patent Document 6, a polyamic acid having a PDA-BPDA block copolymer portion is obtained, but an improvement in the relationship between the composition ratio of each component and the elastic modulus is desired.

JP 59-164328 A JP 61-111359 A JP 63-314242 A JP-A-6-313055 Japanese Patent No. 3687044 JP 2007-162005 A

  An object of this invention is to provide the polyamic-acid composition which can improve the problem of a prior art and can obtain the polyimide film which has the outstanding characteristic. The polyimide film obtained using the polyamic acid composition of the present invention has a thermal expansion characteristic equivalent to that of a copper foil even in a high temperature range, and has high heat resistance.

As means for solving the above-mentioned problems, the present invention is obtained by curing a polyamic acid composition in which a block component composed of ODA and PMDA and a block component composed of PDA and BPDA are copolymerized at a certain ratio. Developed polyimide.
That is, the present invention provides the following.
(1) Paraphenylenediamine: more than 50 mol% to 90 mol% or less and 4,4′-diaminodiphenyl ether: a diamine component consisting of less than 50 mol% to 10 mol% or more, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid A polyamic acid composition comprising a tetracarboxylic acid component consisting of an anhydride: 45-87 mol% and pyromellitic dianhydride: 55-13 mol%,
A block component composed of a copolymer of the paraphenylenediamine and the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, a co-polymer of the 4,4′-diaminodiphenyl ether and the pyromellitic dianhydride. A polyamic acid composition comprising a block component made of a polymer.
(2) A polyimide obtained by curing the polyamic acid composition according to (1) above.
(3) The polyimide whose polyimide as described in said (2) is a film.
(4) The coefficient of thermal expansion in the temperature lowering process from 400 ° C. to 50 ° C. is −18 to −25 ppm / ° C., the glass transition temperature is 350 ° C. or more, and the tensile modulus is 5.8 GPa or less. The polyimide film according to claim 3.
(5) A method for producing the polyamic acid composition according to (1) above,
The 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is mixed in a solvent at a ratio of 90 to 100 mol% with respect to 100 mol% of the paraphenylenediamine, and the paraphenylenediamine is reacted. And a block copolymerized part of the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride,
The 4,4'-diaminodiphenyl ether is added, and then the pyromellitic dianhydride is added and reacted to cause a block copolymer part of the 4,4'-diaminodiphenyl ether and the pyromellitic dianhydride. A process for producing a polyamic acid composition, characterized in that
(6) The manufacturing method of the polyimide which hardens the polyamic-acid composition manufactured by said (5), and obtains a polyimide.
(7) A polyimide film produced by applying the polyamic acid composition produced in (5) above to a substrate, drying to produce a gel film, and then heating the gel film to obtain a polyimide film. Method.

  The polyamic acid composition of the present invention is a polyamic acid composition that can improve the problems of the prior art and obtain a polyimide film having excellent characteristics. The polyimide film obtained using the polyamic acid composition of the present invention has a thermal expansion characteristic equivalent to that of a copper foil even in a high temperature range, and has high heat resistance. Preferably, it has the outstanding characteristic that an elasticity modulus is an appropriate range.

As means for solving the above problems, a polyamic acid composition in which a block component composed of ODA and PMDA and a block component composed of PDA and BPDA are copolymerized at a certain ratio, and a polyimide composition obtained by curing the polyamic acid composition Developed.
The present invention relates to a block component comprising a copolymer of paraphenylenediamine (PDA) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (ODA). And a polyamic acid composition containing a block component made of a copolymer of pyromellitic dianhydride (PMDA). The component ratio is such that PDA in the wholly aromatic diamine component is more than 50 mol% to 90 mol% or more, ODA is less than 50 mol%, 10 mol% or more, and PMDA is 13 to 55 mol% in the wholly aromatic tetracarboxylic acid component, and BPDA is 45 to 45 mol%. 87 mol%.
The polyamic acid composition of the present invention in an organic solvent is included in the composition of the present invention even if there is a partially imidized portion.

In the aromatic diamine component, if the proportion of PDA is less than the above and the proportion of ODA is too large, the resulting polyimide composition will have an excessively low elastic modulus or an excessively high thermal expansion coefficient, which is not preferable. If the elastic modulus is too high, the polyimide film is likely to be broken or cracked in the production process or used for a long time, and a certain degree of flexibility is required for use particularly in COF applications. On the other hand, if the elastic modulus is too low, the handling of the film is deteriorated in the production process and the processing process.
The reason is that the elastic modulus and the coefficient of thermal expansion are both suitable, preferably, PDA is 51 to 90 mol%, ODA is 10 to 49 mol%, and more preferably, PDA is 70 to 90 mol% and ODA is 10 to 10 mol%. 30 mol%.
Further, if the proportion of PDA is larger than the above and the proportion of ODA is too small, the water absorption rate of the resulting polyimide increases, the thermal expansion coefficient decreases too much, or the elastic modulus becomes too high and the moldability is impaired. Absent.

  In the aromatic tetracarboxylic acid component, if the ratio of BPDA is less than the above ratio and the PMDA is excessive, the resulting polyimide has a low elastic modulus or an increased water absorption rate. More than the above ratio, if PMDA becomes too small, the gas permeability of the resulting polyimide is lowered, and it is preferable because bubbles are generated on the surface of the polyamic acid composition or the adhesive strength is reduced during heat curing. Absent. Preferably, BPDA is 50 to 87 mol% and PMDA is less than 13 to 50 mol%.

The polyimide obtained by curing the polyamic acid composition of the present invention preferably has the following characteristics.
The thermal expansion coefficient in the temperature lowering process from 400 ° C. to 50 ° C. is −18 to −25 ppm / ° C., the glass transition temperature is 350 ° C. or higher, and the tensile modulus is 5.8 GPa or lower.
More preferably, the thermal expansion coefficient in the temperature lowering process from 400 ° C. to 50 ° C. is −18 to −24 ppm / ° C., the glass transition temperature is 350 ° C. to 400 ° C., and the tensile elastic modulus is 5 to 5.8 GPa.
The polyimide film obtained by molding this polyimide into a film preferably has an elongation of 50% or more. More preferably, the elongation is 50 to 100%.

  PMDA and BPDA forming the polyamic acid composition may contain an aromatic tetracarboxylic acid component other than these as long as the object of the present invention is not impaired, and specific examples thereof include 2,3 ′, 3, 4'-biphenyltetracarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 2,3,6,7-naphthalenedicarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) ether Pyridine-2,3,5,6-tetracarboxylic acid and amide-forming derivatives thereof. In producing the polyamic acid composition, a small amount of these aromatic tetracarboxylic acid anhydrides may be added.

  The paraphenylene diamine and 4,4′-diaminodiphenyl ether forming the polyamic acid composition can contain an aromatic diamine component other than these as long as they do not impair the object of the present invention. Phenylenediamine, benzidine, paraxylylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, Examples include 1,5-diaminonaphthalene, 3,3′-dimethoxybenzidine, 1,4-bis (3methyl-5aminophenyl) benzene, and amide-forming derivatives thereof. In producing the polyamic acid composition, a small amount of these aromatic diamines may be added.

In the method for producing the polyamic acid composition of the present invention, in a solvent, BPDA is mixed with PDA at a ratio of preferably 90 to 100 mol%, and after mixing and reacting, ODA is added, and then PMDA is completely added. The aromatic tetracarboxylic acid component and the wholly aromatic diamine component are added in an amount that is approximately equimolar, and are mixed and reacted.
The aromatic tetracarboxylic acid component and the aromatic diamine component constituting the polyamic acid are polymerized at a ratio in which the number of moles thereof is approximately equal. This is because when the BPDA is used in a ratio of 90 to 100 mol% with respect to the PDA, there is an advantage that the degree of polymerization can be controlled. More preferably, the BPDA is used in a ratio of 95 to 100 mol% with respect to the PDA.
The polymerization reaction is preferably allowed to proceed for 10 minutes to 30 hours in the temperature range of 0 to 80 ° C. with stirring and / or mixing in an organic solvent. If within the above order, the polymerization reaction is necessary. May be divided or the temperature may be raised or lowered. Vacuum degassing during the polymerization reaction is an effective method for producing an organic solvent solution of a good quality polyamic acid composition.

As the solvent used in the above production method, N, N-dimethylacetamide (hereinafter sometimes abbreviated as DMAc), dimethyl sulfoxide, N-methyl-2-pyrrolidone, N, N-diethylacetamide, N, N- Examples thereof include dimethylformamide, N, N-diethylformamide and dimethylsulfone, and these are preferably used alone or in combination.
The polyamic acid composition obtained by the above production method is preferably prepared in a proportion of 10 to 30% by weight in the solvent.

  When the copolymerized polyamic acid composition obtained by the above production method is cyclized into a copolymerized polyimide, either a chemical cyclization method in which dehydration is performed using a dehydrating agent and a catalyst, or a thermal cyclization method in which thermal dehydration is performed is performed. However, the chemical ring closure method is preferable from the viewpoint of improving the strength of the polyimide film and improving productivity. Examples of the dehydrating agent used in the chemical ring closure method include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as phthalic anhydride, and these are preferably used alone or in combination. Examples of the catalyst include heterocyclic tertiary amines such as pyridine, picoline and quinoline, aliphatic tertiary amines such as triethylamine, and aromatic tertiary amines such as N, N-dimethylaniline. These are preferably used alone or in combination.

  In the above polyimide film production method, when the film is stretched, the polyamic acid composition obtained by a series of reactions is first chemically cyclized using a cyclization catalyst and a dehydrating agent, or is thermally circulated by heat treatment. The ends of the polyimide gel film obtained by crystallization are fixed and biaxial stretching is performed, and the ratio of the stretching ratio in the transverse direction (TD) to the longitudinal direction (MD) (TD / MD) is 0.95-1. It is preferable to adjust to 05. When such a biaxial stretching operation is performed, the mechanical properties of the resulting polyimide film are improved, and the isotropic property is improved.

  In the mechanical properties of the polyimide film, it is preferable to adjust the tensile modulus to 5.8 GPa or less and the elongation to 50% or more. If the mechanical properties are out of the above range, the polyimide film is likely to be broken or cracked during the manufacturing process or long-time use. In addition, in the COF application, the polyimide film becomes too hard and difficult to handle in use.

Hereinafter, the present invention will be described by way of specific examples using Examples and Comparative Examples. The present invention is not limited to the following examples.
Each characteristic of an Example and a comparative example was evaluated with the following method.
(1) Thermal expansion coefficient (thermal expansion coefficient in the temperature lowering process)
Equipment: TMA-50 manufactured by Shimadzu Corporation
Measurement temperature range: 400 ° C to 50 ° C
Temperature increase rate: −10 ° C./min
(2) Tensile modulus and elongation rate In accordance with JISK7113, the following apparatus was used under the following conditions to obtain a stress-strain curve, and the tensile modulus was determined from the gradient of the initial rising portion.
Equipment: AGS-J manufactured by Shimadzu Corporation
Tensile speed: 51 mm / min
Load range: 400 MPa
(3) Glass transition temperature equipment: DMAQ800 manufactured by TA Instruments
Temperature increase rate: 3 ° C / min
Temperature range: 50-450 ° C
Frequency: 1Hz

Example 1
Into a 500 ml separable flask, 255.0 g of DMAc was added, and 10.95 g (0.10 mol) of PDA and 28.12 g (0.096 mol) of BPDA were added thereto and reacted at room temperature and normal pressure for 1 hour. It was. Next, 2.25 g (0.011 mol) of ODA was added and stirred until uniform, then 3.68 g (0.017 mol) of PMDA was added and reacted for 1 hour to obtain a polyamic acid solution. In addition, 15g was taken from this polyamic-acid solution, and it apply | coated to the glass plate using the applicator, and after heat-drying for 20 minutes at 100 degreeC, the gel film was peeled from the glass plate. The ends of the gel film were pinned and biaxially stretched in the MD direction and the TD direction at the stretch ratios shown in Table 1. Then, after heating and drying at 200 ° C. for 20 minutes, 300 ° C. for 20 minutes, and subsequently at 400 ° C. for 20 minutes, pinning was removed to obtain a polyimide film having a thickness of about 30 μm. Each characteristic of this film was evaluated, and the results are shown in Table 1.

(Example 2)
In the same procedure as in Example 1, the aromatic diamine component and the aromatic tetracarboxylic acid component were polymerized with polyamic acid in the molar ratio, the order of addition, and the stretch ratio shown in Table 1, respectively, and a polyimide film was prepared, and each characteristic was evaluated. Table 1 shows the results. In addition, let each component molar ratio be the molar ratio in a wholly aromatic diamine component and a wholly aromatic tetracarboxylic acid component.

(Comparative Examples 1-3)
In the same procedure as in Example 1, the aromatic diamine component and the aromatic tetracarboxylic acid component were polymerized with the polyamic acid composition in the molar ratio, the order of addition, and the stretch ratio shown in Table 1, respectively, and a polyimide film was prepared. Table 1 shows the results. In addition, each component molar ratio was made into the molar ratio in a wholly aromatic diamine component and a wholly aromatic tetracarboxylic acid component.

(Comparative Example 4)
239.1 g of DMAc was used, and 1.870 g (0.0173 mol) of PDA and 3.659 g (0.0168 mol) of PMDA were added thereto and reacted at room temperature and normal pressure for 1 hour. Next, ODA25.398g (0.1268mol) was thrown here and it stirred until it became uniform, Then, BPDA8.481g (0.0288mol) was added, and it was made to react for 1 hour. Subsequently, 21.491 g (0.0985 mol) of PMDA was added thereto, and the mixture was further reacted for 1 hour to obtain a polyamic acid solution. In this polymerization, the addition molar ratio of each raw material was carried out at the ratio shown in Table 2, and a polyimide film having a thickness of about 25 μm was obtained from this polyamic acid solution. The properties of this film were evaluated and are shown in Table 2.

(Comparative Example 5)
The same raw materials as in Example 1, except that 3.27 g (30.2 mmol) of PDA and 223.58 g of N, N-dimethylacetamide were added, and 6.54 g (30.0 mmol) of PMDA was added in several portions. Stir for 1 hour at room temperature under atmosphere. Next, 24.25 g (121.1 mmol) of ODA was added to this and stirred for 30 minutes, and then BPDA and 1.34 g (4.5 mmol) were added in several portions, and after stirring for another 30 minutes, PMDA, 24.51 g (112.4 mmol) was added in several portions. After stirring for 1 hour, 12.68 g of an N, N′-dimethylacetamide solution (6 wt%) of PMDA was added dropwise over 30 minutes, and the mixture was further stirred for 1 hour. From the obtained polyamic acid composition, a polyimide film (average film thickness 30 μm) was obtained using the same method as in Example 1 without stretching.

(Comparative Example 6)
Similar to Comparative Example 7, except that the polyamic acid composition was polymerized at the monomer molar ratio shown in Table 2. From the obtained polyamic acid composition, a polyimide film (average film thickness 30 μm) was obtained in the same manner as in Comparative Example 7.

  The obtained polyimide film was measured for Young's modulus, linear expansion coefficient, and glass transition temperature. Table 2 shows the results.

  The polyimide film of the present invention has a suitable BPDA-ODA block component having excellent physical properties such as elasticity and flexibility suitable for COF applications, thermal expansion equivalent to copper foil even in a high temperature range, and having a lower Tg. Therefore, the film has a Tg of 350 ° C. or higher, so that softening of the film due to high-temperature heat treatment can be reduced.

Claims (7)

Paraphenylenediamine: more than 50 mol% to 90 mol% or less and 4,4′-diaminodiphenyl ether: a diamine component consisting of less than 50 mol% to 10 mol% or more and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride: A polyamic acid composition comprising a tetracarboxylic acid component comprising 45 to 87 mol% and pyromellitic dianhydride: 55 to 13 mol%,
A block component composed of a copolymer of the paraphenylenediamine and the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, a co-polymer of the 4,4′-diaminodiphenyl ether and the pyromellitic dianhydride. A polyamic acid composition comprising a block component made of a polymer.   A polyimide obtained by curing the polyamic acid composition according to claim 1.   The polyimide whose polyimide of Claim 2 is a film. The coefficient of thermal expansion in the temperature lowering process from 400 ° C. to 50 ° C. is −18 to −25 ppm / ° C.
The glass transition temperature is 350 ° C. or higher,
The polyimide according to claim 2 or 3, wherein the tensile elastic modulus is 5.8 GPa or less. A method for producing the polyamic acid composition according to claim 1,
The 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is mixed in a solvent at a ratio of 90 to 100 mol% with respect to 100 mol% of the paraphenylenediamine, and the paraphenylenediamine is reacted. And a block copolymerized part of the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride,
The 4,4'-diaminodiphenyl ether is added, and then the pyromellitic dianhydride is added and reacted to cause a block copolymer part of the 4,4'-diaminodiphenyl ether and the pyromellitic dianhydride. A process for producing a polyamic acid composition, characterized in that   A method for producing a polyimide, comprising: curing the polyamic acid composition produced in claim 5 to obtain a polyimide.   A method for producing a polyimide film comprising applying the polyamic acid composition produced in claim 5 to a substrate and drying to obtain a gel film, and then heating the gel film to obtain a polyimide film.