JP2007169585A - Polyesterimide having low liner thermal expansion coefficient and precursor thereof, and method for producing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyesterimide having a low liner thermal expansion coefficient, a high glass transition temperature, a low water absorption, film toughness sufficient for various applications, and etching characteristics, and useful as an electric insulation film or the like in various kinds of electronic devices; and to provide a precursor thereof, and a method for producing them. <P>SOLUTION: The polyesterimide comprises a repeating unit represented by formula (2) (wherein, X is a divalent aromatic or alicyclic group; the bonding position relation of the divalent group is a para-position or a position corresponding thereto; Y is a 1-12C linear or branched alkyl group or alkoxy group; and Z is a hydrogen atom, a silyl group or a 1-12C linear or branched alkyl group). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyesterimide having a low linear thermal expansion coefficient, a precursor thereof, and a method for producing them.

  Polyimide has not only excellent heat resistance but also chemical resistance, radiation resistance, electrical insulation, excellent mechanical properties, etc., so it can be used for flexible printed circuit boards, tape automation bonding substrates, and semiconductors. Currently, it is widely used in various electronic devices such as protective films for elements and interlayer insulating films for integrated circuits. Polyimide is also a very useful material in terms of simplicity of production method, high film purity, and ease of improving physical properties, and functional polyimide material designs suitable for various applications have been made in recent years.

  Many polyimides are insoluble in organic solvents and do not melt above the glass transition temperature, so it is usually not easy to mold the polyimide itself. For this reason, polyimide is generally obtained by reacting an aromatic tetracarboxylic dianhydride such as pyromellitic anhydride and an aromatic diamine such as diaminodiphenyl ether in an equimolar polar organic solvent such as N, N-dimethylacetamide. First, a polyimide precursor having a high degree of polymerization is polymerized, this solution is formed into a film or the like, and heated and dehydrated (imidized) at 250 ° C. to 350 ° C. to form a film.

  Thermal stress generated in the process of cooling the polyimide / metal substrate laminate from the imidization temperature to room temperature often causes serious problems such as curling, film peeling and cracking. Recently, with the increasing density of electronic circuits, multilayer wiring boards have come to be used. However, even if film peeling or cracking does not occur, residual stress in the multilayer board significantly increases device reliability. Reduce.

  As a measure for reducing thermal stress, it is effective to reduce the thermal expansion of polyimide itself as an insulating film. Most polyimides have a linear thermal expansion coefficient in the range of 50-100 ppm / K, which is much higher than the linear thermal expansion coefficient of 17 ppm / K for metal substrates such as copper, so it is close to the value of copper, approximately 20 ppm / K or less. Research and development of a low thermal expansion polyimide exhibiting

  In general, it has been reported that lowering the thermal expansion of polyimide is a necessary condition that the main chain structure is linear and the internal rotation is constrained and rigid (see Non-Patent Document 1, for example). Polyimide obtained from pyromellitic anhydride and 4,4'-diaminodiphenyl ether exhibits high film toughness due to the ether bond present in the main chain, but its linear thermal expansion coefficient is as high as 40 to 50 ppm / K and exhibits low thermal expansion characteristics. Not shown.

  As a practically low thermal expansion polyimide material, a polyimide formed from 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine is most well known. This polyimide film is known to exhibit a very low linear thermal expansion coefficient of 5 to 10 ppm / K depending on the film thickness and production conditions (see, for example, Non-Patent Document 2).

  However, since polyimides exhibiting a low linear thermal expansion coefficient have a rigid and linear main chain structure without exception, most of them are insoluble in organic solvents. Therefore, polyimide film formation requires a heat curing step at a high temperature after the film is formed at the stage of a polyimide precursor soluble in a solvent.

  On the other hand, when polyimide is soluble in an organic solvent, the polyimide film is formed by applying a polyimide organic solvent solution (varnish) on a metal substrate and then evaporating and drying the solvent at a temperature much lower than the thermal imidization temperature. Therefore, it is possible to reduce the thermal stress in the metal substrate / insulating film laminate.

  In addition, polyimide is generally known to have a high water absorption rate. Water absorption in the insulating layer causes serious problems such as dimensional change of the insulating film and deterioration of electrical characteristics. As a molecular design for realizing a low water absorption rate, it has been reported that introduction of an ester bond into a polyimide skeleton is effective (for example, see Non-Patent Document 3).

  In recent years, increasing the calculation speed of microprocessors and shortening the rise time of clock signals have become important issues in the information processing and communication fields. It is necessary to lower the dielectric constant. Also, for high-density wiring and a multilayer substrate for shortening the electrical wiring length, the lower the dielectric constant of the insulating film is advantageous in that the insulating layer can be made thinner.

  However, for example, the above polyimide obtained from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine described above exhibits excellent low thermal expansion properties, but the dielectric constant is 3. As high as 5, it is insufficient in terms of dielectric constant.

  In general, introduction of a fluorine substituent into a skeleton is effective for reducing the dielectric constant and water absorption of polyimide (see, for example, Non-Patent Document 4). However, the use of fluorinated monomers is disadvantageous in terms of cost. In addition, replacing aromatic units with alicyclic units to reduce π electrons is an effective means for reducing the dielectric constant (see, for example, Non-Patent Document 5).

  However, the use of alicyclic monomers often causes significant problems during polymerization. When an alicyclic diamine is used, salt formation occurs in the initial stage of polymerization, and not only the reproducibility of the polymerization reaction is lowered, but in an extreme case, polymerization does not proceed at all. The types of alicyclic tetracarboxylic dianhydrides having a sufficiently high polymerization reactivity in practical use are very limited.

  Thus, it is easy in terms of molecular design to obtain a polyimide having a low linear thermal expansion coefficient (20 ppm / K), a low water absorption (1.0% or less), and a low dielectric constant (3.2 or less). However, practical materials that satisfy such required properties are hardly known at present, except for fluorinated polyimide, which is disadvantageous in terms of cost. Low dielectric constant polymer materials and inorganic materials other than polyimide are also being studied, but at present the required characteristics are not sufficiently satisfied in terms of dielectric constant, heat resistance and toughness.

  Furthermore, in recent years, a photosensitive polyimide system in which photosensitive performance is imparted to polyimide or its precursor itself has been actively studied for the purpose of through-hole formation and fine processing on polyimide as an insulating layer. On the other hand, etching is performed on polyimide itself using a base to form through holes. However, in the latter, since the etching rate of the polyimide film with alkali is usually slow, the etching solution is limited to a special base such as ethanolamine, and even if ethanolamine is used, it cannot be applied to all polyimides.

  Therefore, in addition to the above required characteristics, if it can be easily etched with a general-purpose base such as an aqueous potassium hydroxide solution, an extremely useful material can be provided in the industrial field, but such a material is not known at present. is there.

Polymer, 28,228 (1987) Macromolecules, 29, 7897 (1996) Polymer Proceedings, 53, 4115 (2004) Macromolecules, 24, 5001 (1991) Macromolecules, 32, 4933 (1999)

  The present invention relates to an electrical insulating film in various electronic devices, a flexible printed wiring board, and a display substrate, having a low linear thermal expansion coefficient, a high glass transition temperature, a low water absorption rate, a film toughness sufficient for various applications, and etching characteristics. The present invention provides a polyesterimide, a precursor thereof, and a production method thereof, useful as an electronic paper substrate, a solar cell substrate, and a photosensitive material.

  In view of the above problems, as a result of intensive research, it has been found that the polyesterimide and its precursor composed of the repeating unit represented by the formula (2) of the present invention are useful materials in the industrial field. The invention has been completed.

That is, the present invention is as follows.
1. Formula (1):

(In the formula, X represents a divalent aromatic group or alicyclic group, and the bonding positional relationship of the divalent group is in the para position or a relationship corresponding thereto; In which Z represents a hydrogen atom, a silyl group, or a linear or branched alkyl group having 1 to 12 carbon atoms). A polyesterimide precursor.
2. The polyesterimide precursor which consists of a repeating unit represented by Formula (1) whose intrinsic viscosity is the range of 0.1-8.0 dL / g.
3. A polyesterimide precursor comprising a repeating unit represented by the formula (1), wherein X is a 1,4-phenylene group optionally substituted with one or more alkyl groups having 1 to 4 carbon atoms.
4). Formula (2):

(Wherein X and Y are the same as those in formula (1)), a polyesterimide.
5. A polyesterimide consisting of repeating units represented by formula (2), wherein X is a 1,4-phenylene group optionally substituted with one or more alkyl groups having 1 to 4 carbon atoms.
6). A process for producing a polyesterimide of formula (2), wherein the polyesterimide precursor of formula (1) is subjected to a cyclization reaction (imidation) using heating or a dehydrating reagent.
7). Formula (3), which is a raw material for the polyesterimide precursor:

(Wherein X is the same as in formula (1))
A tetracarboxylic dianhydride represented by formula (4):

(Wherein Y is the same as in formula (1))
A process for producing a polyesterimide of the formula (2), wherein a polycondensation reaction is carried out with a diamine represented by the formula (2) in a solvent at a high temperature.
8). The photosensitive resin composition containing the polyesterimide precursor which consists of a repeating unit represented by Formula (1), and a diazo naphthoquinone type photosensitive agent.
9. The said photosensitive resin composition in which the polyesterimide precursor which consists of a repeating unit represented by Formula (1) contains the structural unit induced | guided | derived from the diamine containing a fluorine and / or an imide group.
10. A pattern forming method using a positive photosensitive resin,
(A) Step of applying a solution of the photosensitive resin composition to a substrate and drying to obtain a photosensitive film (b) Exposing the film obtained in (a) above through a photomask, A method comprising developing with an aqueous solution to form a pattern, and (c) imidating the resulting pattern with heating or using a dehydrating cyclization reagent.

  In general, in order for a polymer film to exhibit sufficient film toughness, entanglement between polymer chains is necessary, and the degree of entanglement increases with an increase in the degree of polymerization of the polymer. In addition, even if the molecular weight is high, if the main chain does not contain any bendable bond that can rotate internally, the polymer chain cannot be entangled and the membrane becomes fragile. Excessive introduction of ether bonds into the polyimide skeleton greatly contributes to the improvement of the film toughness, but on the other hand, the rigidity and linearity of the main chain are lowered, which may hinder the expression of low thermal expansion characteristics.

  According to the present invention, it is possible to provide a resin having a low linear thermal expansion coefficient, a low water absorption rate, a high glass transition temperature, sufficient film toughness, and alkali etching characteristics. In order to achieve both low thermal expansion characteristics and film toughness, the present invention has focused on para-ester bonds. The para-ester bond is considered to have a higher internal rotation barrier than the ether bond, relatively prevent the conformational change, and also impart some flexibility to the main chain, giving a flexible film.

  Since ester bonds have a lower polarizability per unit volume than amide bonds and imide bonds, introduction of ester bonds into polyimide is advantageous for lowering the dielectric constant. In view of the fact that polyester generally exhibits a low water absorption rate compared to polyimide and polyamide, it is considered that introduction of ester groups contributes to a decrease in the amount of adsorbed water (water absorption rate) that greatly affects the dielectric constant.

  Moreover, since the polyesterimide of this invention does not contain a fluorine group in the repeating unit, it can maintain a comparatively high glass transition temperature. On the other hand, the ester bond in the polyesterimide of the present invention enables alkali etching by hydrolysis when fine processing such as through-hole formation is required.

  In the polyesterimide comprising the repeating unit represented by the formula (2) of the present invention, the paraester bond is included not only in the tetracarboxylic dianhydride structural unit but also in the diamine structural unit. In this case, the paraester group is contained at a high concentration, and it is expected that the effect of introducing the paraester group as described above is enhanced.

  In the polymerization of the polyesterimide precursor of the present invention, the diamine represented by the formula (4) is used, and the characteristic of the diamine is the presence of a substituent represented by Y in the formula. When this substituent is not present (Y = hydrogen atom), the polymerization reaction is carried out in combination with a tetracarboxylic dianhydride having a rigid structure, so that the resulting polyimide precursor has an extremely rigid skeleton, so that the polymerization solution Among them, lyotropic liquid crystallinity is exhibited, and there is a possibility that a high polymer cannot be obtained due to non-uniformity of the polymerization solution, gelation, precipitation of the polyimide precursor, and the like. It is considered that the presence of the substituent Y moderately weakens the aggregation of the polyimide precursor chains and can avoid the above serious problems.

  The bonding position of the substituent Y is also important. If the substituent Y is present at the ortho position (3 position) with respect to the amino group, the polymerization reactivity may be lowered due to steric hindrance. In the diamine represented by the formula (4) according to the present invention, since the substituent Y is present at the meta position (2 position) with respect to the amino group, there is no problem of a decrease in polymerization reactivity due to steric hindrance.

  Further, it is considered that the presence of the bulky substituent Y reduces the polarizability per unit volume and contributes to the low dielectric constant of the polyimide film. Moreover, it is thought that the substituent Y disturbs the packing of polyimide chains, and contributes to preventing the clouding and weakening of the film accompanying the crystallization of polyimide.

  Moreover, the tetracarboxylic dianhydride represented by the said Formula (3) or its derivative (s) is used in the polyesterimide precursor polymerization of this invention. Since the polyesterimide of the present invention contains a paraester group at a high concentration, it has a structure similar to that of a wholly aromatic polyester composed of para bonds, but the film forming processability is greatly different. Normally, wholly aromatic polyesters composed of para bonds are insoluble and infusible, and the molding processability is very poor. However, in the polyesterimide of the present invention, the precursor is dissolved in an organic solvent, and the storage stability of the varnish is also high. Therefore, the film forming processability is good.

  Thus, the present invention can provide an industrially very useful polyesterimide. Due to the structural characteristics such as rigidity, low polarizability, hydrophobicity, alkali hydrolyzability, and steric bulk of the substituents in the paraester group in the raw material, a low linear thermal expansion coefficient, low A material having physical properties that cannot be obtained by conventional materials such as water absorption, high glass transition temperature, low dielectric constant, and etching characteristics can be obtained.

  Embodiments of the present invention will be described in detail below, but these are examples of the embodiments of the present invention and the present invention is not limited to these contents.

<Method for producing polyesterimide precursor>
The method for producing the polyesterimide precursor of the present invention is not particularly limited, and a known method can be applied. More specifically, it is obtained by the following method. First, the diamine represented by the formula (4) is dissolved in a dehydrated polymerization solvent, and substantially equimolar ester group-containing tetracarboxylic dianhydride powder represented by the formula (3) is gradually added thereto. Stir at room temperature for 0.5 to 100 hours using a mechanical stirrer. In this case, the monomer concentration is 5 to 50% by weight, preferably 10 to 40% by weight.

  The ester group-containing tetracarboxylic dianhydride used in this case has the formula (3):

It is represented by In the formula, X represents a divalent aromatic group or an alicyclic group, and the bonding positional relationship of the divalent group is in the para position or a relationship corresponding thereto.

  In the present invention, the “para position or a relationship corresponding thereto” means a relationship in which the other coupling position is point-symmetric or line-symmetric with respect to one coupling position. For example, in the case of a 6-membered ring such as benzene or cyclohexane, it means 1,4-. In the case of a 10-membered ring such as a naphthalene ring, 2,6-, 1,5- or 1,4- means. (Note that the number representing the substitution position varies depending on the order of priority in the nomenclature, but the relationship between the two is maintained regardless of the number.) In the present invention, the divalent group X Since the bonding positional relationship is in the para position or a relationship corresponding thereto, a linear and rigid structure is given.

  Although it does not specifically limit as a bivalent aromatic group, For example, it is a C6-C24 monocyclic and condensed polycyclic hydrocarbon group, These are mutually or directly by a bridge member depending on the case. It may be connected. The bridging member is a spacer group having 1 to 6 atoms, and may be, for example, alkylene, —O—, —NH—, carbonyl, sulfinyl, sulfonyl or a combination thereof. Furthermore, they may optionally be substituted with one or more halogens, hydroxyl, or alkyl, halogenated alkyl or alkoxy having 1 to 4 carbon atoms.

  Preferable specific examples of the divalent aromatic group include a 1,4-phenylene group and a 2,6-naphthylene group, which are optionally substituted with one or more alkyls having 1 to 4 carbon atoms. . A particularly preferred embodiment is a 1,4-phenylene group optionally substituted with one or more alkyls having 1 to 4 carbon atoms.

  Although it does not specifically limit as a bivalent alicyclic group, For example, it is a C6-C24 monocyclic and polycyclic hydrocarbon group, These are mutually or directly by a bridge member depending on the case. It may be connected. The bridging member is a spacer group having 1 to 6 atoms, and may be, for example, alkylene, —O—, —NH—, carbonyl, sulfinyl, sulfonyl or a combination thereof. Furthermore, they may optionally be substituted with one or more halogens, hydroxyl, or alkyl having 1 to 4 carbon atoms, alkyl halides or alkoxy and / or one or more —O—, —NH. It may be interrupted by-, carbonyl, sulfinyl, or sulfonyl.

  Preferable specific examples of the divalent alicyclic group include 1,4-cyclohexylene, 4,4'-bicyclohexylene group and the like.

  In the present invention, from the viewpoint of production cost and monomer purity, the formula (5) or the formula (6):

It is desirable to use an ester group-containing tetracarboxylic dianhydride represented by the formula (X = 1,4-phenylene group or 2-methyl-1,4-phenylene group).

  In addition, the synthesis | combination of the tetracarboxylic dianhydride monomer represented by Formula (3) can be performed by a conventional method. For example, a desired diol that gives the corresponding X is dissolved in a dehydrated organic solvent such as tetrahydrofuran or N, N-dimethylformamide, and a tertiary amine such as pyridine or triethylamine is added thereto as a deoxidizer. To this solution, a solution of trimellitic anhydride chloride in an amount of 2 moles with respect to the diol used was gradually added dropwise while cooling with ice, and stirred at room temperature for 24 hours, thereby being represented by the formula (3). A tetracarboxylic dianhydride monomer can be obtained.

  On the other hand, the ester group-containing diamine used in the production of the polyesterimide precursor has the formula (4):

It is represented by In the formula, Y represents a linear or branched alkyl group having 1 to 12 carbon atoms or an alkoxy group. Examples of these include straight groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, and n-dodecyl. A linear or branched alkyl group, or an alkoxy group in which the alkyl group part is the linear or branched alkyl group, such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butyloxy group, a tert -Butyloxy group, n-hexyloxy group, n-octyloxy group, n-dodecyloxy group and the like.

  Preferable specific examples of the substituent Y are a linear or branched alkyl group having 1 to 6 carbon atoms or an alkoxy group, particularly a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, In addition to linear or branched alkyl groups such as isobutyl group and tert-butyl group, alkoxy groups such as methoxy group, ethoxy group, n-propoxy group and isopropoxy group can be mentioned. In the present invention, from the viewpoint of production cost and monomer purity, preferably the formula (7):

An ester group-containing diamine represented by the formula (Y = methyl group) is used.

  The polyesterimide precursor of the present invention is known from tetracarboxylic acid dialkyl ester dichloride which is a derivative of an ester group-containing tetracarboxylic dianhydride represented by the formula (3) and a diamine represented by the formula (4). It is also possible to perform low-temperature solution polycondensation according to the method (High Performance Polymers, 10, 11 (1998)). Specifically, first, an ester group-containing diamine represented by the formula (4) is dissolved in a polymerization solvent, and then an appropriate amount of a tertiary amine such as pyridine or triethylamine is added to the solution as a deoxidizer. Next, a diamine and a substantially equimolar amount of a tetracarboxylic acid dialkyl ester dichloride are gradually added to the solution, and the mixture is stirred in an ice bath or at room temperature for 0.5 to 72 hours using a mechanical stirrer. In this case, the monomer concentration is 5 to 50% by weight, preferably 10 to 40% by weight.

  A similar polymerization reaction can also be performed by an interfacial polycondensation method. That is, the diamine is dissolved in an aqueous solution in which a base is dissolved as a deoxidizer. On the other hand, tetracarboxylic acid diester dichloride is dissolved in a nonpolar organic solvent that does not dissolve in water such as toluene or cyclohexane. Then, these two solutions are mixed and vigorously stirred with a mechanical stirrer to obtain the polyesterimide precursor of the present invention. In this case, there is no problem even if the amounts of diamine and tetracarboxylic acid diester dichloride are not equimolar.

  The polyesterimide precursor of the present invention can be directly polycondensed from tetracarboxylic acid dialkyl ester and equimolar diamine using diamine and equimolar triphenyl phosphite as a condensing agent in the presence of pyridine. It is. Further, even when N, N-dicyclohexylcarbodiimide is used as a condensing agent, direct polycondensation can be similarly performed.

  Further, the polyesterimide precursor of the present invention is obtained by converting a diamine disilylate and a tetracarboxylic dianhydride or a tetracarboxylic acid dialkyl ester dichloride according to a known method (Preliminary Proceedings of the Polymeric Discussion Society, 49, 1917 (2000)). It is also possible to perform low-temperature solution polycondensation as in

  Thus, by applying a known method, preferably by applying any of the methods described above, the formula (1) of the present invention:

(In the formula, X represents a divalent aromatic group or alicyclic group, and the bonding positional relationship of the divalent group is in the para position or a relationship corresponding thereto; In which Z represents a hydrogen atom, a silyl group, or a linear or branched alkyl group having 1 to 12 carbon atoms). A polyesterimide precursor can be obtained.

  It will be understood that, in the formula, Z depends on the starting material selected depending on the production method of the polyesterimide precursor to be applied. For example, when starting from an ester group-containing tetracarboxylic dianhydride represented by the formula (3) and a diamine represented by the formula (4), a polyester comprising a repeating unit represented by the formula (1) is obtained. In the imide precursor, Z is a hydrogen atom. Further, for example, when starting from a tetracarboxylic acid dialkyl ester dichloride which is a derivative of an ester group-containing tetracarboxylic dianhydride represented by the formula (3) and a diamine represented by the formula (4), the formula obtained In the polyesterimide precursor composed of repeating units represented by (1), Z is alkyl.

  Hereinafter, as a preferred specific example, a polyesteramide that is a polyesterimide precursor is obtained by reacting an ester group-containing tetracarboxylic dianhydride represented by the formula (3) with an ester group-containing diamine represented by the formula (4). A method for producing an acid will be described. First, the diamine is dissolved in a polymerization solvent, tetracarboxylic dianhydride powder is gradually added thereto, and a mechanical stirrer is used, and 0 to 100 ° C., preferably 5 to 60 ° C., most preferably at room temperature, 0. Stir for 5 to 100 hours, preferably 1 to 50 hours. In this case, the monomer concentration is 5 to 50% by weight, preferably 10 to 40% by weight. By carrying out the polymerization in this monomer concentration range, a polyesterimide precursor solution having a uniform and high degree of polymerization can be obtained. From the viewpoint of the film toughness of the polyesterimide, it is desirable that the degree of polymerization of the polyesterimide precursor is as high as possible. When the polymerization is performed at a concentration lower than the above monomer concentration range, the degree of polymerization of the polyimide precursor is not sufficiently high, and the finally obtained polyimide film may be brittle, which is not preferable. In addition, when polymerization is performed at a high concentration, there is a fear that the monomer and the polymer to be produced are not sufficiently dissolved.

  The polyesterimide precursor comprising the repeating unit represented by the formula (1) and the polyesterimide comprising the repeating unit represented by the formula (2) are only composed of the repeating unit represented by the formula (1). This means not only the polyesterimide precursor and the polyesterimide consisting only of the repeating unit represented by the formula (2), but also includes those each containing such a repeating unit as a main constituent unit. Therefore, the ester group-containing tetracarboxylic dianhydride represented by the formula (3) is used in the polymerization of the polyesterimide precursor within a range not impairing the required characteristics of the polyesterimide of the present invention and the polymerization reactivity of the polyesterimide precursor. Tetracarboxylic dianhydrides other than those can be partially used.

  Such a partially usable tetracarboxylic dianhydride is not particularly limited, but pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3, 3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylsulfone tetracarboxylic acid Dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propane dianhydride, 1,4, 5,8-naphthalenetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, etc. It is. These may be used alone or in combination of two or more as copolymerization components.

  In order to satisfy the required characteristics of the polyesterimide of the present invention, it is preferable to use 60 mol% or more of the ester group-containing tetracarboxylic dianhydride represented by the formula (3) in the tetracarboxylic dianhydride component, It is more preferable to use 70 mol% or more.

  Similarly, a diamine other than the diamine represented by the formula (4) is added in the polymerization of the polyesterimide precursor within the range where the required properties of the polyesterimide according to the present invention and the polymerization reactivity of the polyesterimide precursor are not impaired. Can be used in part. Examples of such partially usable aromatic diamines include, but are not limited to, for example, 3,3′-bistrifluoromethyl-4,4′-diaminobiphenyl, 3,3′-bistrifluoromethyl-5,5. '-Diaminobiphenyl, bis (trifluoromethyl) -4,4'-diaminodiphenyl, bis (fluorinated alkyl) -4,4'-diaminodiphenyl, dichloro-4,4'-diaminodiphenyl, dibromo-4,4 '-Diaminodiphenyl, bis (fluorinated alkoxy) -4,4'-diaminodiphenyl, diphenyl-4,4'-diaminodiphenyl, 4,4'-bis (4-aminotetrafluorophenoxy) tetrafluorobenzene, 4, 4′-bis (4-aminotetrafluorophenoxy) octafluorobiphenyl, 4,4′-bi Phthylamine, o-, m- or p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, diaminodurene, diaminoisodurene, dimethyl-4,4'- Diaminodiphenyl, dimethoxy-4,4′-diaminodiphenyl, diethoxy-4,4′-diaminodiphenyl, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4 '-Diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis ( 4-aminophenoxy) benzene, 1,4-bis (4- Minophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2 -Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) Phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (4-amino-2-trifluoromethylphenoxy] phenyl) hexafluoropropane 2,2-bis [4- (3-amino-5-trifluoromethylphenoxy) phenyl] hexafluoropropane, 2,2 -Bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2 -Bis (3-amino-4-methylphenyl) hexafluoropropane, 4,4'-bis (4-aminophenoxy) octafluorobiphenyl, 4,4'-diaminobenzanilide, etc. It can also be used in combination.

  Similarly, the aliphatic diamine that can be partially used is not particularly limited. For example, 4,4′-methylenebis (cyclohexylamine), isophoronediamine, trans-1,4-diaminocyclohexane, cis-1,4- Diaminocyclohexane, 1,4-cyclohexanebis (methylamine), 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) bicyclo [2.2.1] Heptane, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] decane, 1,3-diaminoadamantane, 2,2-bis (4-aminocyclohexyl) propane, 2,2-bis (4 -Aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pen Diamine, 1,6-hexamethylene diamine, 1,7-heptamethylene diamine, 1,8-octamethylene diamine, 1,9-nonamethylenediamine, and the like. Two or more of these may be used in combination.

  For example, as will be described later, when the polyesterimide precursor of the present invention is used in combination with a photosensitive agent, fluorine and / or an imide group, which is known as a structural unit having an alkali dissolution inhibiting effect, as a copolymerization component, etc. It is preferred to use a diamine containing Such components have been reported in known literature (for example, Masatoshi Hasegawa, Azumi Tominaga, Photopolymer Science and Technology, Vol. 18, 307-312 (2005)), and the like, for example, the following formula (8):

Can be mentioned.

  In order to satisfy the required characteristics of the polyesterimide, the ester group-containing diamine represented by the formula (4) is preferably used in an amount of 60 mol% or more, more preferably 70 mol% or more in the diamine component.

  The solvent used in the polymerization reaction is preferably an aprotic solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, etc., but the raw material monomer and the resulting polyester There is no problem if the imide precursor is dissolved, and the structure is not particularly limited. Specifically, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ- Cyclic ester solvents such as caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol Phenol solvents such as 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. In addition, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxy Add ethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpenes, mineral spirits, petroleum naphtha solvents, etc. Can be used.

  The polyesterimide precursor of the present invention may be used as it is as a varnish. Further, if desired, the precipitated polyesterimide precursor can be filtered and dried and isolated as a powder by dropping it into a large amount of poor solvent such as water or methanol. The polyesterimide precursor powder thus obtained can be redissolved in the polymerization solvent to obtain a polyesterimide precursor varnish.

  The polyesterimide precursor of the present invention has an intrinsic viscosity measured in N, N-dimethylacetamide at 30 ° C. and a concentration of 0.5% by weight in the range of 0.1 to 8.0 dL / g. Depending on the application, it is preferably in the range of 0.3 to 6.0 dL / g.

<Method for producing polyesterimide>
The polyesterimide of the present invention can be produced by subjecting the polyesterimide precursor obtained by the above method to a dehydration ring-closing reaction (imidation reaction). At this time, usable forms of the polyesterimide are a film, a powder, a molded article and a solution.

  First, a method for producing a polyesterimide film will be described. A polymerization solution (varnish) of a polyesterimide precursor is cast on a glass, copper, aluminum, silicon, or other substrate and dried in an oven at 40 to 180 ° C, preferably 50 to 150 ° C. The obtained polyesterimide precursor film is heated on a substrate in a vacuum, in an inert gas such as nitrogen, or in air at 200 to 430 ° C, preferably 250 to 400 ° C. An imide film can be produced. When the heating temperature is lower than this, the imidization ring-closing reaction is incomplete, which is not preferable. When the heating temperature is too high, the produced polyesterimide film may be partially thermally decomposed. The imidization is preferably performed in a vacuum or in an inert gas, but if the imidization temperature is not too high, it may be performed in air.

  Further, the imidization reaction can be carried out by immersing the polyesterimide precursor film in a solution containing a dehydrating reagent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine instead of the heat treatment.

  In addition, a polyesterimide can be obtained by heating the polymerization solution of the polyesterimide precursor as it is or after appropriately diluting with the same solvent to 150 to 200 ° C.

  Furthermore, the polyesterimide of this invention is a raw material of the polyesterimide precursor of this invention, Formula (3):

(Wherein X is the same as in formula (1))
A tetracarboxylic dianhydride represented by formula (4):

(Wherein Y is the same as in formula (1))
It can also be directly produced by polycondensation reaction in the polymerization solvent at a high temperature of 100 to 250 ° C., preferably 150 to 200 ° C.

  In these reactions, when the produced polyesterimide itself is soluble in the solvent used, the solution may be used as it is as the varnish of the polyesterimide of the present invention. Moreover, the polyesterimide can also be isolated as a powder by dripping the obtained solution in a large amount of poor solvents such as water and methanol, filtering and drying. The polyesterimide powder thus obtained can be redissolved in the polymerization solvent to obtain a polyesterimide varnish. On the other hand, when insoluble in a solvent, crystalline polyesterimide powder can be obtained as a precipitate. At this time, benzene, toluene, xylene or the like may be added in order to azeotropically distill off water or the like as a by-product of imidization. Further, a base such as γ-picoline can be added as a catalyst.

  The polyesterimide film can also be formed by applying the varnish of polyesterimide on a substrate and drying at 40 to 400 ° C., preferably 100 to 250 ° C.

  A polyesterimide molded body can be produced by heating and compressing the polyesterimide powder obtained as described above at 200 to 450 ° C., preferably 250 to 430 ° C.

  Furthermore, by adding and stirring a dehydrating reagent such as N, N-dicyclohexylcarbodiimide or trifluoroacetic anhydride in the polyesterimide precursor solution and reacting at 0 to 100 ° C, preferably 0 to 60 ° C, An isomeric polyisoimide is formed. The isoimidization reaction can also be performed by immersing the polyesterimide precursor film in a solution containing the dehydrating reagent. The polyisoimide varnish can be easily converted into a polyesterimide by heat treatment at 250 to 450 ° C., preferably 270 to 400 ° C., after film formation in the same procedure as described above.

  Additives such as an oxidation stabilizer, a filler, a silane coupling agent, a photosensitizer, a photopolymerization initiator, and a sensitizer can be added to the polyesterimide of the present invention and its precursor as necessary.

  Accordingly, the present invention also relates to a photosensitive resin composition comprising a polyesterimide precursor and a diazonaphthoquinone photosensitizer, each comprising a repeating unit represented by formula (1). Such a photosensitive resin composition can be prepared by adding and dissolving a diazonaphthoquinone photosensitizer in the varnish of the polyesterimide precursor described above.

  Specific examples of the diazonaphthoquinone photosensitizer include 1,2-naphthoquinone-2-diazide-5-sulfonic acid, 1,2-naphthoquinone-2-diazide-4-sulfonic acid, and esters of low molecular hydroxy compounds, such as Esters with low molecular weight hydroxy compounds such as 2,3,4-trihydroxybenzophenone, 1,3,5-trihydroxybenzene, 2- or 4-methyl-phenol, 4,4′-hydroxy-propane, typically Can include 2,3,4-tris (1-oxo-2-diazonaphthoquinone-5-sulfoxy) benzophenone. The blending ratio of the diazonaphthoquinone photosensitizer in the photosensitive resin composition of the present invention is 10 to 40% by weight, more preferably 20 to 30% by weight, based on the polyesterimide precursor. If the amount is too small, the difference in solubility between the exposed and unexposed portions is too small to allow pattern formation by development. If the amount is too large, the film properties of the polyesterimide (toughness, linear thermal expansion coefficient, glass transition temperature, heat resistance) And other serious problems such as a large film loss after imidization.

  This varnish is applied onto a substrate such as copper, silicon or glass using a spin coater or bar coater, and is preferably dried in warm air at 40 to 120 ° C. for 0.1 to 3 hours under light shielding to obtain a film thickness. A photosensitive film of 1 to 10 μm can be obtained. The polyesterimide precursor of the present invention is originally soluble in alkali, but the one formed into a film containing a diazonaphthoquinone photosensitizer is a film in which the diazonaphthoquinone photosensitizer acts as a dissolution inhibitor. It itself becomes alkali insoluble. On the other hand, when this film is exposed to light through a photomask, for example, with ultraviolet light, the diazonaphthoquinone photosensitizer in the exposed area is changed to alkali-soluble indenecarboxylic acid by a photoreaction, so that only the exposed area can be converted into an alkaline aqueous solution. It becomes melted. Therefore, a positive pattern can be formed.

  It is preferable to perform the said photosensitive film formation process at 120 degrees C or less. Above this temperature, the diazonaphthoquinone photosensitizer may start to thermally decompose. On the other hand, when a film is formed at a low temperature, for example, 60 ° C., a large amount of solvent may remain. In such a case, the film may be prebaked at 80 to 120 ° C. for 1 to 30 minutes prior to the exposure operation, but it is also effective to immerse the film in water for 1 to 5 minutes. The residual solvent may cause swelling of the film and pattern collapse during development, and it is preferable to sufficiently remove the residual solvent in order to obtain a clear pattern.

  The photosensitive film is exposed through a photomask, for example, irradiated with i-line of a high-pressure mercury lamp at room temperature for 10 seconds to 1 hour, and then alkaline aqueous solution, for example, 0.05 to 10% by weight, preferably 0.1 to 5%. A clear positive fine pattern can be obtained by developing for 10 seconds to 10 minutes at room temperature using an aqueous tetramethylammonium hydroxide solution in weight%, and further rinsing with pure water.

  When developing with an alkaline aqueous solution, if the difference in solubility between the exposed area and the unexposed area is insufficient, a clear relief pattern may be difficult to obtain. In this case, it is possible to control the solubility in an aqueous alkali solution by synthesizing a copolymer using an appropriate monomer other than the monomer constituting the polyesterimide precursor of the present invention. Although it does not specifically limit as a monomer which can be used in this case, The monomer containing specific functional groups, such as a fluorine group and an imide group known as a structural unit which has an alkaline dissolution inhibitory effect, is used suitably, and said formula ( The compound 8) is particularly preferably used. That is, in the case of the photosensitive resin composition containing the diazonaphthoquinone photosensitizer of the present invention described above, the polyesterimide precursor of the present invention is a structural unit derived from a diamine containing fluorine and / or an imide group, particularly a formula ( It is preferable that the structural unit derived from the compound of 8) is included.

  By heat-treating the fine pattern of the polyimide precursor formed on the substrate in air, in an inert gas atmosphere such as nitrogen or in vacuum, at a temperature of 200 ° C. to 430 ° C., preferably 250 ° C. to 400 ° C. A clear polyimide film pattern is obtained. Imidization can also be performed chemically using a dehydrating cyclization reagent. That is, a polyimide film can also be obtained by a method in which an imide group-containing polyimide precursor film formed on a substrate is immersed in acetic anhydride containing a basic catalyst such as pyridine or triethylamine at room temperature for 1 minute to several hours.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical property values in the following examples were measured by the following methods.

<Infrared absorption spectrum>
Using a Fourier transform infrared spectrophotometer (FT-IR5300 manufactured by JASCO Corporation), the infrared absorption spectrum of the polyesterimide precursor and the polyesterimide thin film was measured by the transmission method, and the ester group-containing tetracarboxylic acid diester was measured by the KBr method. The infrared absorption spectrum of the anhydride was measured.
^<1 H-NMR spectrum>
A ¹ H-NMR spectrum of an ester group-containing tetracarboxylic dianhydride was measured in deuterated dimethyl sulfoxide using an JEOL NMR spectrophotometer (ECP400).
<Differential scanning calorimetry (melting point and melting curve)>
The melting point and melting curve of the ester group-containing tetracarboxylic dianhydride were measured using a differential scanning calorimeter (DSC3100) manufactured by Bruker Ax in a nitrogen atmosphere at a heating rate of 2 ° C./min. The higher the melting point and the sharper the melting peak, the higher the purity of the compound.
<Intrinsic viscosity>
An N, N-dimethylacetamide solution of 0.5% by weight polyesterimide precursor was measured at 30 ° C. using an Ostwald viscometer.
<Glass transition temperature: Tg>
The glass transition temperature of the polyesterimide film was determined from a loss peak at a frequency of 0.1 Hz and a heating rate of 5 ° C./min by dynamic viscoelasticity measurement using a thermomechanical analyzer (TMA4000) manufactured by Bruker Ax.
<Linear thermal expansion coefficient: CTE>
The range of 100 to 200 ° C. from the elongation of the test piece at a load of 0.5 g / film thickness of 1 μm and a heating rate of 5 ° C./min by thermomechanical analysis using a Bruker Ax thermomechanical analyzer (TMA4000). The linear thermal expansion coefficient of the polyesterimide film was determined as an average value at.
<5% weight loss temperature: T _d ⁵ >
When the initial weight of the polyesterimide film is reduced by 5% in the temperature rising process at a heating rate of 10 ° C./min in nitrogen or air using a thermogravimetric analyzer (TG-DTA2000) manufactured by Bruker Ax The temperature of was measured. Higher values indicate higher thermal stability.
<Light transmittance (transparency)>
The light transmittance at 365, 400, and 435 nm was measured using an ultraviolet-visible spectrophotometer (V-530) manufactured by JASCO Corporation. Higher transmittance means better transparency of the film.
<Cutoff wavelength (transparency)>
Using a UV-visible spectrophotometer (V-530) manufactured by JASCO Corporation, the visible / ultraviolet transmittance from 200 nm to 900 nm was measured. The wavelength (cutoff wavelength) at which the transmittance was 0.5% or less was used as an index of transparency. The shorter the cutoff wavelength, the better the transparency of the film.
<Birefringence>
The refractive index _{in the} direction parallel to the polyesterimide film (n _in ) and _{in the} direction perpendicular to (n _out ) was measured with an Abbe refractometer (Abago refractometer (Abbe 4T), sodium lamp used, wavelength 589 nm). The birefringence (Δn = n _in −n _out ) was determined from the difference in refractive index.
<Dielectric constant>
Based on the average refractive index [n _av = (2n _in + n _out ) / 3] of the polyesterimide film using an Abbe refractometer (Abbe 4T) manufactured by Atago Co., according to the following formula: ε _cal = 1.1 × n _av ² The dielectric constant (ε _cal ) of the polyesterimide film at 1 MHz was calculated.
<Water absorption rate>
Polyesterimide (film thickness: 20 to 30 μm) that had been vacuum-dried at 50 ° C. for 24 hours was immersed in water at 25 ° C. for 24 hours, and then excess water was wiped off, and the water absorption (%) was determined from the weight increase.
<Elastic modulus, elongation at break>
Using a tensile tester (Tensilon UTM-2) manufactured by Toyo Baldwin, a tensile test (stretching speed: 8 mm / min) was performed on a test piece (3 mm × 30 mm) of a polyesterimide film, and the initial stress-strain curve The elastic modulus was determined from the gradient, and the elongation at break (%) was determined from the elongation at the time the film was broken. Higher elongation at break means higher film toughness.

(Synthesis Example 1)
<Synthesis of ester group-containing tetracarboxylic dianhydride>
In a well-dried three-necked flask with a stirrer, 40 mmol of hydroquinone was dissolved in a mixed solvent of 20 mL of anhydrous tetrahydrofuran and 16 mL of anhydrous pyridine, and the reaction vessel was sealed with a septum cap. While cooling in an ice bath, a solution of 80 mmol of trimellitic anhydride chloride in anhydrous tetrahydrofuran (76 mL) was gradually added dropwise to this solution with a syringe. Stir. After completion of the reaction, the desired product and a mixture of white pyridine hydrochloride as a by-product were filtered off. In order to remove the water-soluble pyridine hydrochloride, this was washed with water and washed with a 1% silver nitrate solution until no chlorine component in the washing solution could be confirmed. By this operation, the target product is partially hydrolyzed to open the ring. Therefore, the crude product obtained for ring closure is vacuum-dried at 200 ° C. for 24 hours and then recrystallized from anhydrous 1,4-dioxane. did. The crystals separated by filtration were further vacuum-dried at 200 ° C. for 24 hours. Higher purity ester group-containing tetracarboxylic dianhydride (formula (5)) from infrared absorption spectrum (FIG. 1), ¹ H-NMR spectrum (FIG. 2), and differential scanning calorimetry (melting curve, FIG. 3) Compound) was obtained.

(Synthesis Example 2)
In a well-dried three-necked flask with a stirrer, 40 mmol of methylhydroquinone was dissolved in a mixed solvent of anhydrous tetrahydrofuran, 20 mL, and anhydrous pyridine 16 mL, and the reaction vessel was sealed with a septum cap. While cooling in an ice bath, a solution of 80 mmol of trimellitic anhydride chloride in anhydrous tetrahydrofuran (76 mL) was gradually added dropwise to this solution with a syringe. Stir for hours. After completion of the reaction, the desired product and a mixture of white pyridine hydrochloride as a by-product were filtered off. In order to remove the water-soluble pyridine hydrochloride, this was washed with water and washed with a 1% silver nitrate solution until no chlorine component in the washing solution could be confirmed. By this operation, the target product is partially hydrolyzed to open the ring. Therefore, the crude product obtained for ring closure is vacuum-dried at 200 ° C. for 24 hours and then recrystallized from anhydrous 1,4-dioxane. did. The crystals separated by filtration were further vacuum-dried at 200 ° C. for 24 hours. Higher purity ester group-containing tetracarboxylic dianhydride (formula (6)) than infrared absorption spectrum (FIG. 4), ¹ H-NMR spectrum (FIG. 5), and differential scanning calorimetry (melting curve, FIG. 6) Compound) was obtained.

Example 1
<Polymerization of polyesterimide precursor, imidization and evaluation of polyesterimide film characteristics>
N in which the ester group-containing diamine represented by the formula (7) (4-amino-2-methylphenyl 4′-aminobenzoate) 5 mmol was put in a well-closed sealed reaction vessel with a stirrer and sufficiently dehydrated with molecular sieves 4A , N-dimethylacetamide was dissolved in 7 mL, and 5 mmol of an ester group-containing tetracarboxylic dianhydride powder represented by the formula (5) was gradually added to this solution. After 10 minutes, the solution viscosity increased rapidly, so the solvent was gradually added to dilute, and finally a total of 18 mL of solvent was added. Further, the mixture was stirred at room temperature for 24 hours to obtain a transparent, uniform and viscous polyimide precursor solution. This polyesterimide precursor solution did not precipitate or gel at all even when allowed to stand at room temperature and −20 ° C. for one month, and showed extremely high solution storage stability. The intrinsic viscosity of the polyimide precursor measured with an Ostwald viscometer at 30 ° C. and a concentration of 0.5% by weight in N, N-dimethylacetamide was 2.06 dL / g.

  The polyimide precursor solution obtained by applying this polyimide precursor solution to a glass substrate and drying at 60 ° C. for 2 hours was subjected to thermal imidization on the substrate at 250 ° C. under reduced pressure for 2 hours, and then the residual stress was reduced. In order to remove it, it was peeled off from the substrate and further heat treated at 300 ° C. for 1 hour to obtain a transparent polyimide film having a thickness of 20 μm. This polyimide film did not break even in the 180 ° bending test and showed flexibility. Moreover, it did not show any solubility in any organic solvent. As a result of dynamic viscoelasticity measurement of this polyimide film, a clear glass transition point (determined from the loss peak in the dynamic viscoelastic curve) was not observed, but a broad loss peak that seems to be a glass transition was observed around 380 ° C. Although it was seen, it did not show any thermoplasticity. This shows that this polyimide film has extremely high dimensional stability. Further, the linear thermal expansion coefficient (average value between 100 ° C. and 200 ° C.) showed a very low linear thermal expansion coefficient of 6.8 ppm / K. Judging from the very large birefringence value (Δn = 0.181), this is considered to be due to the high in-plane orientation of the polyimide chain. The dielectric constant estimated from the average refractive index is 3.17. The dielectric constant of a typical wholly aromatic low thermal expansion polyimide composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine is used. The value was lower than the rate (3.5). This result is the effect of introducing an ester group into the polyimide skeleton. The 5% weight loss temperature was high at 472 ° C. in nitrogen and 449 ° C. in air. Further, the water absorption was an extremely low value of 0.6%. This is the effect of introducing a paraester group. The mechanical properties were tensile strength (Young's modulus) 7.03 GPa, breaking strength 0.256 GPa, high strength and high elasticity, and breaking elongation was 10%, indicating a certain degree of toughness as a high modulus film. Thus, this polyesterimide exhibited a very low linear thermal expansion coefficient, low water absorption, excellent dimensional stability, high thermal stability, relatively low dielectric constant and sufficient film toughness. Table 1 summarizes the physical property values. Infrared absorption spectra of the obtained polyesterimide precursor thin film and polyesterimide thin film are shown in FIGS. 7 and 8, respectively.

(Example 2)
In addition to 4-amino-2-methylphenyl 4'-aminobenzoate, a polyesterimide precursor was prepared according to the method described in Example 1 except that 4,4'-oxydianiline was used as the other copolymerized diamine component. Was polymerized, and film formation, thermal imidization, and heat treatment were performed to produce a polyesterimide film having a thickness of 20 μm, and physical properties were similarly evaluated. The copolymer composition is 4-amino-2-methylphenyl 4′-aminobenzoate: 4,4′-oxydianiline = 70: 30. The physical property values are shown in Table 1. It exhibited linear thermal expansion coefficient close to copper, low water absorption, excellent dimensional stability, high thermal stability, and relatively low dielectric constant. In particular, much higher film toughness (elongation at break) was obtained than the polyesterimide of Example 1. This is because a flexible ether bond is introduced into the main chain.

(Example 3)
Implemented except that the ester group-containing tetracarboxylic dianhydride represented by the formula (6) is used in place of the ester group-containing tetracarboxylic dianhydride represented by the formula (5) as the tetracarboxylic dianhydride component. A polyesterimide precursor was polymerized in the same manner as described in Example 1 to form a polyesterimide film having a thickness of 20 μm by film formation, thermal imidization, and heat treatment, and physical properties were similarly evaluated. The physical property values are shown in Table 1. It exhibited a very low coefficient of linear thermal expansion, low water absorption, excellent dimensional stability, high thermal stability, and a relatively low dielectric constant.

Example 4
Implemented except that the ester group-containing tetracarboxylic dianhydride represented by the formula (6) is used in place of the ester group-containing tetracarboxylic dianhydride represented by the formula (5) as the tetracarboxylic dianhydride component. A polyesterimide precursor was polymerized in the same manner as described in Example 2, and film formation, thermal imidization, and heat treatment were performed to produce a 20 μm-thick polyesterimide copolymer film, and physical properties were similarly evaluated. The physical property values are shown in Table 1. It exhibited linear thermal expansion coefficient close to copper, low water absorption, excellent dimensional stability, high thermal stability, and relatively low dielectric constant. In particular, much higher film toughness (elongation at break) was obtained than the polyesterimide of Example 3. This is because a flexible ether bond is introduced into the main chain.

(Example 5)
Positive pattern formation 4-amino-2-methylphenyl 4'-aminobenzoate (14 mmol) and diamine (3 mmol) represented by the above formula (8) as another copolymerization component, and formula (5) A polyesterimide precursor was polymerized from the ester group-containing tetracarboxylic dianhydride powder (17 mmol) according to the method described in Example 1. The intrinsic viscosity was 0.617 dL / g. The light transmittance of this polyesterimide precursor film (film thickness: 30 μm) was 9.2% at 365 nm, 78.2% at 400 nm, 86.6% at 435 nm, and the cutoff wavelength was 354 nm.

  In the polymerization solution, 2,3,4-tris (1-oxo-2-diazonaphthoquinone-5-sulfoxy) benzophenone as a diazonaphthoquinone photosensitizer is added to 30% by weight based on the mass of the polyesterimide precursor. Was added and dissolved. This was apply | coated on the glass substrate surface-treated with the silane coupling agent, and it was made to dry in a hot air dryer at 60 degreeC for 2 hours, and the photosensitive film with a film thickness of 8 micrometers was obtained. This film was pre-baked at 100 ° C. for 10 minutes, and then irradiated with i-line (365 nm, irradiation light intensity = about 150 mW / cm 2) of an epi-illumination type high-pressure mercury lamp (Harrison Toshiba Lighting Co., Ltd. Toscure 251) for 5 seconds through a photomask. . This was developed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide at 20 ° C. for 5 minutes, rinsed with water, and then dried at 60 ° C. for several minutes. Thermal imidization was carried out by raising the temperature stepwise in vacuum at 250 ° C. for 1 hour and further at 300 ° C. for 1 hour, and a clear relief pattern having a line width of 20 μm was obtained. The light transmittance of the polyesterimide film (thickness: 21 μm) containing no photosensitizer was 0.1% at 365 nm, 23.2% at 400 nm, and 63.7% at 435 nm. The cutoff wavelength was 373 nm. Other film properties are a glass transition temperature of 340 ° C. and a linear thermal expansion coefficient of 13.7 ppm / K, and are shown in Table 1 together with other physical properties such as birefringence and dielectric constant.

(Example 6)
4-amino-2-methylphenyl 4′-aminobenzoate (12 mmol) and a diamine (4 mmol) represented by the formula (8) as another copolymerization component, and an ester group-containing tetracarboxylic acid represented by the formula (5) A polyesterimide precursor was polymerized from acid dianhydride powder (16 mmol) according to the method described in Example 1. The intrinsic viscosity was 0.591 dL / g. The light transmittance of this polyesterimide precursor film (film thickness: 18 μm) was 22.0% at 365 nm, 79.6% at 400 nm, 86.2% at 435 nm, and the cutoff wavelength was 350 nm.

  2,3,4-tris (1-oxo-2-diazonaphthoquinone-5-sulfoxy) benzophenone as a diazonaphthoquinone photosensitizer in the polymerization solution is 30% by weight based on the mass of the polyesterimide precursor. Were added and dissolved. This was apply | coated on the glass substrate surface-treated with the silane coupling agent, and it was made to dry in a hot air dryer at 60 degreeC for 2 hours, and the photosensitive film with a film thickness of 8 micrometers was obtained. This film was pre-baked at 100 ° C. for 10 minutes, and then irradiated with i-line (365 nm, irradiation light intensity = about 150 mW / cm 2) of an epi-illumination type high-pressure mercury lamp (Harrison Toshiba Lighting Co., Ltd. Toscure 251) for 5 seconds through a photomask. . This was developed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide at 20 ° C. for 5 minutes, rinsed with water, and then dried at 60 ° C. for several minutes. Thermal imidization was carried out by raising the temperature stepwise in vacuum at 250 ° C. for 1 hour and further at 300 ° C. for 1 hour, and a clear relief pattern having a line width of 20 μm was obtained. The light transmittance of the polyesterimide film (film thickness: 24 μm) not containing a photosensitizer was 0.3% at 365 nm, 33.5% at 400 nm, and 70.0% at 435 nm. The cutoff wavelength was 367 nm. Other film properties are a glass transition temperature of 380 ° C. and a linear thermal expansion coefficient of 19.6 ppm / K, and are shown in Table 1 together with other physical properties such as birefringence and dielectric constant.

(Comparative Example 1)
A polyimide precursor was polymerized according to the method described in Example 1 except that p-phenylenediamine was used instead of 4-amino-2-methylphenyl 4′-aminobenzoate. The intrinsic viscosity of the polyimide precursor measured with an Ostwald viscometer in N, N-dimethylacetamide at a concentration of 0.5% by weight at 30 ° C. was 5.19 dL / g. According to the method described in Example 1, film formation, thermal imidization, and heat treatment were performed, and the physical properties of the obtained film (film thickness = 20 μm) were evaluated. The physical property values are summarized in Table 1. Like the polyesterimide described in Example 1, it exhibited an extremely low coefficient of linear thermal expansion, excellent dimensional stability, and high thermal stability, but the water absorption was 1.6%, which is higher than that of the polyesterimide described in Example 1. Value. The elongation at break was also a low value of 5.4%. These are caused by not using an ester group-containing diamine for the diamine component.

(Comparative Example 2)
The polyesterimide precursor was polymerized according to the method described in Example 1 except that 4-aminophenyl 4'-aminobenzoate having no substituent was used instead of 4-amino-2-methylphenyl 4'-aminobenzoate. . The intrinsic viscosity of the polyimide precursor measured with an Ostwald viscometer in N, N-dimethylacetamide at a concentration of 0.5% by weight at 30 ° C. was 2.81 dL / g. According to the method described in Example 1, film formation, thermal imidization, and heat treatment were performed, and the physical properties of the obtained film (film thickness = 20 μm) were evaluated. The physical property values are shown in Table 1. Similar to the polyesterimide described in Example 1, it exhibited a very low coefficient of linear thermal expansion, high dimensional stability, high thermal stability, and sufficient film toughness, but had a dielectric constant of 3.26 and a water absorption of 0. It was a value higher than the polyesterimide film described in Example 1 together with .8%. This is because an ester-containing diamine containing no substituent is used as the diamine component.

  Since the polyesterimide of the present invention has a low linear thermal expansion coefficient, a low water absorption, a high glass transition temperature, a low dielectric constant, a sufficient film toughness and an alkali etching property, an electrical insulating film and a flexible printed wiring board in various electronic devices, It can be used for display substrates, electronic paper substrates, solar cell substrates, photosensitive materials, and the like.

2 is an infrared absorption spectrum of an ester group-containing tetracarboxylic dianhydride (compound of formula (5)) described in Synthesis Example 1. 2 is a ¹ H-NMR spectrum of an ester group-containing tetracarboxylic dianhydride (compound of formula (5)) described in Synthesis Example 1. FIG. 2 is a differential scanning calorimetric analysis (melting curve) of the ester group-containing tetracarboxylic dianhydride (compound of formula (5)) described in Synthesis Example 1. 3 is an infrared absorption spectrum of an ester group-containing tetracarboxylic dianhydride (compound of formula (6)) described in Synthesis Example 2. 2 is a ¹ H-NMR spectrum of an ester group-containing tetracarboxylic dianhydride (compound of formula (6)) described in Synthesis Example 2. FIG. 3 is a differential scanning calorimetry analysis (melting curve) of the ester group-containing tetracarboxylic dianhydride (compound of formula (6)) described in Synthesis Example 2. 2 is an infrared absorption spectrum of the polyesterimide precursor film described in Example 1. 2 is an infrared absorption spectrum of the polyesterimide film described in Example 1.

Claims (10)

Formula (1):

(Where
X represents a divalent aromatic group or an alicyclic group, and the bonding positional relationship of the divalent group is in the para position or a relationship corresponding thereto,
Y represents a linear or branched alkyl group having 1 to 12 carbon atoms or an alkoxy group, and Z represents a hydrogen atom, a silyl group, or a linear or branched alkyl group having 1 to 12 carbon atoms. Polyesterimide precursor consisting of repeating units represented by   The polyesterimide precursor according to claim 1, comprising a repeating unit represented by formula (1) having an intrinsic viscosity of 0.1 to 8.0 dL / g.   X consists of a repeating unit represented by formula (1), which is a 1,4-phenylene group optionally substituted with one or more alkyl having 1 to 4 carbon atoms. The polyesterimide precursor described. Formula (2):

(Wherein X and Y are the same as those in formula (1)), a polyesterimide.   5. The repeating unit according to claim 4, wherein X is a 1,4-phenylene group optionally substituted with one or more alkyls having 1 to 4 carbon atoms. Polyesterimide.   The method for producing a polyesterimide according to claim 4, wherein the polyesterimide precursor according to claim 1 is subjected to a cyclization reaction (imidization) using heating or a dehydrating reagent. Formula (3), which is a raw material for the polyesterimide precursor:

(Wherein X is the same as in formula (1))
A tetracarboxylic dianhydride represented by formula (4):

(Wherein Y is the same as in formula (1))
5. The method for producing a polyesterimide according to claim 4, wherein a polycondensation reaction is performed with a diamine represented by the formula below in a solvent at a high temperature.   The photosensitive resin composition containing the polyesterimide precursor in any one of Claims 1-3, and a diazo naphthoquinone type photosensitive agent.   The photosensitive resin composition of Claim 8 in which the polyesterimide precursor in any one of Claims 1-3 contains the structural unit induced | guided | derived from the diamine containing a fluorine and / or an imide group. A pattern forming method using a positive photosensitive resin,
(A) The process of apply | coating the solution of the photosensitive resin composition of Claim 8 or 9 to a board | substrate, and drying and obtaining a photosensitive film (b) The film obtained by said (a) is used as a photomask. And a step of forming a pattern by exposure with an alkaline aqueous solution, and (c) imidating the obtained pattern with a heating or dehydrating cyclization reagent.

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