WO2022215743A1 - Curable composition and cured product - Google Patents

Curable composition and cured product Download PDF

Info

Publication number
WO2022215743A1
WO2022215743A1 PCT/JP2022/017330 JP2022017330W WO2022215743A1 WO 2022215743 A1 WO2022215743 A1 WO 2022215743A1 JP 2022017330 W JP2022017330 W JP 2022017330W WO 2022215743 A1 WO2022215743 A1 WO 2022215743A1
Authority
WO
WIPO (PCT)
Prior art keywords
polyimide precursor
curable composition
oxazoline
absorption peak
polyimide
Prior art date
Application number
PCT/JP2022/017330
Other languages
French (fr)
Japanese (ja)
Inventor
慎治 宇都宮
Original Assignee
住友ファーマフード＆ケミカル株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友ファーマフード＆ケミカル株式会社 filed Critical 住友ファーマフード＆ケミカル株式会社
Priority to JP2023513053A priority Critical patent/JPWO2022215743A1/ja
Publication of WO2022215743A1 publication Critical patent/WO2022215743A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
    • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
    • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors

Definitions

  • the present invention relates to, for example, a curable composition that becomes a cured product by curing treatment, and a cured product obtained by curing the curable composition.
  • a curable composition that is cured by a curing treatment for example, a curable composition containing at least a polyimide precursor obtained by partially hydrolyzing the imide bonds of a polyimide resin is known.
  • the polyimide precursor has in its molecule a plurality of cyclic imide structures and a plurality of amic acid structures (carboxy groups and amide groups) capable of forming cyclic imide structures by imidization reaction.
  • the amic acid structure in the polyimide precursor is imidized (dehydration condensation reaction) to form an imide bond, thereby producing a cured product. Since the resulting cured product has heat resistance, electrical insulation, etc., this type of curable composition is used to form a cured product such as an insulating coating material by a curing treatment.
  • Examples of the curable composition as described above include an imide group-containing compound (polyimide precursor) obtained by partially hydrolyzing a polyimide molded article, an epoxy compound, and a blocked isocyanate compound.
  • Patent Document 1 The curable composition described in Patent Document 1 can be cured by a relatively low-temperature curing treatment, can improve the adhesion (adhesion) of the cured product to the adherend, and can improve the heat resistance of the cured product. .
  • an imide group-containing compound obtained by partially hydrolyzing a polyimide molded article, an aqueous solvent, and an amine compound having a boiling point of 85 to 145 ° C.
  • the imide group-containing compound has an absorption peak at a wave number of 1500 cm -1 derived from the benzene ring and an absorption peak at a wave number of 1375 cm -1 derived from the imide group in the infrared spectroscopy chart.
  • Patent Document 2 When the height of the absorption peak at a wave number of 1500 cm ⁇ 1 derived from a benzene ring is S1 and the height of an absorption peak at a wave number of 1375 cm ⁇ 1 derived from an imide group is S2, the ratio of S1/S2 A curable composition having a ratio in the range of 2 to 10 is known (Patent Document 2).
  • the curable composition described in Patent Document 2 has good stability while containing an aqueous solvent such as water, and can be cured by a relatively low-temperature curing treatment.
  • An object of the present invention is to provide a curable composition capable of producing a cured product having uniformity, flexibility, and adhesion to an adherend. .
  • the curable composition according to the present invention is a polyimide precursor in which a part of the imide bond of the polyimide resin is hydrolyzed, and an oxazoline compound having an oxazoline ring in the molecule,
  • the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
  • the oxazoline compound may be a polymer compound.
  • the curable composition according to the present invention may further contain an aqueous solvent.
  • the polyimide precursor has a benzene ring in the molecule, and the infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor has an absorption peak at a wave number of 1500 cm -1 due to the benzene ring.
  • the cured product according to the present invention is obtained by curing the above curable composition.
  • FIG. 2 is a diagram showing a schematic molecular structural formula of each example of polyimide resin before hydrolysis.
  • FIG. 3 is an IR chart of an example polyimide resin before hydrolysis.
  • the curable composition of the present embodiment includes a polyimide precursor in which a portion of the imide bond of the polyimide resin is hydrolyzed, and an oxazoline compound having an oxazoline ring in the molecule,
  • the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor. According to the curable composition of the present embodiment, a cured product having uniformity, flexibility, and adhesion to an adherend can be produced.
  • the polyimide precursor has multiple cyclic imide structures and multiple amic acid structures in the molecule.
  • Each amic acid structure contains a carboxy group and an amide group.
  • a carboxy group and an amide group in each amic acid structure can be imidized (dehydration condensation reaction) by curing treatment such as heating to form an imide bond (imide group).
  • imidization creates a new cyclic imide structure.
  • the amic acid structure is a structure obtained by hydrolyzing the imide bond that constitutes the cyclic imide structure
  • the cyclic imide structure is a structure obtained by imidization (dehydration condensation reaction) of the carboxy group and the amide group in the amic acid structure.
  • the polyimide precursor described above is a hydrolyzate of a polyimide resin, it may have a carboxy group at the molecular chain end.
  • a commercially available product can be used as the polyimide resin before hydrolysis.
  • polyimide resin products include the product name “Kapton” series (manufactured by Toray DuPont), the product name “Upilex” series (manufactured by Ube Industries, Ltd.), and the product name “Aurum” (manufactured by Mitsui Chemicals, Inc.). be able to. Specific examples of the molecular structures of these polyimide resins will be described in detail later (see FIG. 1).
  • As the polyimide resin before hydrolysis it is preferable to use a polyimide precursor obtained by hydrolyzing a polyimide resin film or the like, which has conventionally been discarded, from the viewpoint of protecting the global environment. As a result, the polyimide resin can be recycled more actively, and a cured product having uniformity, flexibility, and adhesion to the adherend can be produced.
  • the above polyimide precursor has, for example, a molecular structure represented by the following general formula (1).
  • Ar may include at least one of an aromatic structure, a cyclic saturated hydrocarbon structure, a linear or branched saturated hydrocarbon structure, an ether group, and the like.
  • Ar' may contain at least one of, for example, an aromatic structure, a cyclic saturated hydrocarbon structure, a branched saturated hydrocarbon structure, an ether group, and the like.
  • the repeating structural unit in the above polyimide precursor corresponds to the repeating structural unit in the polyimide resin before hydrolysis.
  • the polyimide resin before hydrolysis has a structure in which structural units of a reaction product of a diamine monomer and a tetracarboxylic acid (dianhydride) monomer are repeated in the molecule.
  • the above polyimide precursor also has similar repeating structural units in its molecule.
  • part of the cyclic imide structure is hydrolyzed to an amic acid structure, so the part in parentheses on the left side of general formula (1) is also represented by general formula (1)
  • the parts in parentheses on the right side of are also repeating structural units.
  • the number of moles of the repeating structural unit can be calculated as follows.
  • the repeating structural unit of the polyimide resin before hydrolysis is, for example, the portion in parentheses on the right side of the general formula (1).
  • the number of moles of the repeating structural unit can be calculated by dividing (dividing) the mass of the polyimide resin by the molecular weight of the portion inside the right parenthesis.
  • the number of nitrogen atoms in the repeating structural unit is two. Therefore, the amount of the oxazoline ring of the oxazoline compound with respect to 1 mol of the repeating structural unit of the polyimide precursor can also be expressed as the amount per 2 mol of nitrogen atoms in the polyimide precursor.
  • the above polyimide precursor is a hydrolyzate obtained by partially hydrolyzing a plurality of imide bonds in the polyimide resin, so the above polyimide precursor is represented on the left side of general formula (1)
  • the molecule has both the amic acid structure (portion indicated by ⁇ ) shown on the right side and the cyclic polyimide structure (portion indicated by ⁇ ) shown on the right side.
  • the above polyimide precursor preferably has an aromatic structure (particularly a benzene ring structure) in its molecule.
  • an aromatic structure particularly a benzene ring structure
  • the cured product can exhibit higher heat resistance.
  • the molar ratio of the number of nitrogen atoms to one benzene ring may be 0.2 or more and 1.0 or less, or 0.4 or more and 0.8 or less.
  • Such a molar ratio can be analyzed by infrared spectroscopic analysis, NMR measurement, or the like, which will be described later.
  • Ar may be Ar-1 (structure having one benzene ring) or Ar-2 (structure having two benzene rings), as shown below.
  • Ar' may be Ar'-1 (structure having two benzene rings) or Ar'-2 (structure having one benzene ring).
  • Ar may be Ar-1 (having one benzene ring) and Ar' may be Ar'-1 (having two benzene rings).
  • the polyimide precursor of this embodiment is a hydrolysis reaction product of polyimide resin.
  • the method for producing the above polyimide precursor will be described in detail later.
  • the average molecular weight (mass average molecular weight) of the polyimide precursor may be, for example, 1,000 or more and 100,000 or less.
  • the average molecular weight (weight average molecular weight) of the polyimide precursor is preferably 3,000 or more, more preferably 5,000 or more.
  • the average molecular weight (weight average molecular weight) is preferably 60,000 or less, more preferably 30,000 or less. When the weight average molecular weight of the polyimide precursor is within the above range, the solubility in the solvent described later becomes better.
  • the mass average molecular weight of the polyimide precursor is determined by gel permeation chromatography (GPC) measurement. Details of the GPC measurement conditions are as follows. Device name: Tosoh product name “HLC-8320GPC” Detector: Differential refractive index (RI) detector Column: Styrenedivinylbenzene (average particle size: 3 ⁇ m, average pore size: 2 nm) Column temperature: 40°C Standard substance for creating a calibration curve: polyethylene glycol Data processing software: software attached to the above equipment Eluent: N,N-dimethylacetamide (DMAc) [Number average molecular weight (Mn), mass average molecular weight (Mw), molecular weight distribution (Mw/Mn)]
  • DMAc N,N-dimethylacetamide
  • the Mw/Mn of the polyimide precursor determined by the GPC measurement is preferably 1.0 or more, more preferably 1.5 or more. Such Mw/Mn is preferably 3.0 or less, more preferably 2.5 or less. When the Mw/Mn of the polyimide precursor is 1.0 or more and 3.0 or less, there is an advantage that the physical properties of the cured product are made more uniform and stabilized. In the hydrolysis reaction product of the polyimide resin, that is, in the above-described polyimide precursor produced by hydrolysis of the polyimide resin, the Mw/Mn can fall within the above range.
  • each wavenumber shown below is a numerical value for defining the absorption peak in the vicinity of the wavenumber, as is commonly judged in the technical field of infrared spectroscopic analysis. In other words, each wavenumber shown below does not represent only an absorption peak having a peak apex at that wavenumber.
  • the infrared spectroscopic analysis of the polyimide precursor is carried out under the following measurement conditions. Infrared spectroscopic analysis can be performed using a commercially available measuring instrument under the following measurement conditions.
  • Device name Fourier transform infrared spectrophotometer (“FT/IR-4600” manufactured by JASCO Corporation) Analysis method: Attenuated Total Reflection (ATR) Measurement wavenumber range: 4000 cm -1 to 400 cm -1
  • the polyimide precursor of the present embodiment exhibits an absorption peak P1 due to a benzene ring at (near) 1500 cm -1 wavenumber in the infrared spectrum when analyzed by infrared spectroscopy, as shown in FIG. 5, for example.
  • the polyimide precursor in the present embodiment exhibits an absorption peak P2 due to the imide group at (near) 1375 cm -1 wavenumber in the infrared spectroscopic spectrum when analyzed by infrared spectroscopy, as shown in FIG. 5, for example. Since the polyimide precursor has an imide group in its molecule, a cured product produced by a curing treatment such as heating has good heat resistance.
  • the polyimide precursor in the present embodiment exhibits an absorption peak P3 due to an amide group (-NHCO-) at (near) 1600 cm -1 wavenumber, as shown in Fig. 5, for example. Since the polyimide precursor has an amide group in its molecule, it can be cured at a relatively low temperature.
  • the polyimide precursor in the present embodiment exhibits an absorption peak P4 due to a carboxy group (—COOH) at (near) 1413 cm ⁇ 1 wavenumber, as shown in FIG. 5, for example. Since the polyimide precursor has a carboxyl group in the molecule, it has good solubility in the solvent described later, and the cured product after curing treatment can have good adhesion.
  • the polyimide precursor in this embodiment exhibits an absorption peak P5 due to a carbonyl group (—CO—) at (near) 1710 cm ⁇ 1 wavenumber, as shown in FIG. 5, for example.
  • the polyimide precursor has a carbonyl group in its molecule, and thus has good solubility in the solvent described below.
  • the imide group amount (absorption peak height), the amide group amount (absorption peak height), and the carboxy group amount in the polyimide precursor can be an index indicating the degree of hydrolysis of the polyimide resin.
  • the degree of hydrolysis can be confirmed by determining the height of the absorption peak of each functional group with respect to the height of the absorption peak of the benzene ring whose chemical structure does not change even by hydrolysis.
  • the height of the absorption peak P2 due to the imide group, the height of the absorption peak P3 due to the amide group, and the absorption due to the carboxy group can be an index indicating the degree of hydrolysis of the polyimide resin.
  • the above height ratios P1/P2, P1/P3, P1/P4 can be employed.
  • each ratio of the heights of the absorption peaks described above is calculated as follows.
  • the horizontal axis is the wavenumber [cm -1 ]
  • the vertical axis is the transmittance [%] (upper side is 100% transmittance) Infrared spectrum spectrum (IR chart).
  • IR chart Infrared spectrum spectrum
  • the baseline height [%] is 90 [%]
  • the height of the absorption peak P1 is 70 [%]
  • the height of the absorption peak P2 is 80 [%]
  • ) 2.0
  • the ratio of the height of the absorption peak P1 due to the benzene ring to the height of the absorption peak P2 due to the imide group P1/P2
  • the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P2 at a wave number of 1375 cm -1 due to the imide group is preferably 2 or more, and may be 3 or more.
  • the ratio (P1/P2) is preferably 10 or less, more preferably 9 or less, and more preferably 5 or less.
  • the polyimide precursor can be cured at a lower temperature because the height ratio (P1/P2) is within the above range. Moreover, it can have better solubility in the solvent described later. In addition, the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
  • the ratio of the height of the absorption peak P1 due to the benzene ring to the height of the absorption peak P3 due to the amide group is preferably 2 or more, more preferably 3 or more. Also, the ratio (P1/P3) is preferably 20 or less, more preferably 12 or less, even more preferably 10 or less.
  • the polyimide precursor can have better solubility in the solvent described below.
  • the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
  • the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P4 at a wave number of 1413 cm -1 due to the carboxy group is preferably 2 or more, more preferably 3 or more. Also, the ratio (P1/P4) is preferably 20 or less, more preferably 12 or less, and even more preferably 11 or less. When the height ratio (P1/P4) is within the above range, the polyimide precursor can have better solubility in the solvent described below. In addition, the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
  • the benzene ring in the above polyimide precursor may be an unsubstituted benzene ring, or a substituted benzene ring in which hydrogen atoms respectively bonded to a plurality of carbon atoms constituting the benzene ring are substituted with substituents.
  • the substituent of the substituted benzene ring is, for example, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an alkoxysilyl group having 1 to 3 carbon atoms, or a trifluoromethyl group. There may be.
  • the benzene ring in the polyimide precursor is an unsubstituted benzene ring, a benzene ring substituted with an alkoxysilyl group having 1 to 3 carbon atoms, or a benzene ring substituted with a trifluoromethyl group. More preferably, the benzene ring in the polyimide precursor is an unsubstituted benzene ring.
  • a monovalent substituent such as a halogen atom
  • the monovalent group bonded to the carbon atoms constituting the benzene ring is preferably a hydrogen atom (--H).
  • polyimide precursor for example, a polyimide precursor represented by formula (3) described later can be used.
  • a partial hydrolyzate obtained by partially hydrolyzing the product name "Kapton H" manufactured by DuPont-Toray Co., Ltd.
  • the polyimide precursor in the present embodiment can be obtained by subjecting a discarded polyimide resin film to hydrolysis treatment.
  • the oxazoline compound contained in the curable composition of this embodiment is a compound containing one or more oxazoline rings in the molecule.
  • Oxazoline compounds include low-molecular-weight compounds and high-molecular-weight compounds.
  • the oxazoline compound may be a low-molecular-weight oxazoline compound with a molecular weight of less than 1,000, or a high-molecular-weight oxazoline compound with a molecular weight of 1,000 or more.
  • Examples of low-molecular-weight oxazoline compounds include compounds in which two oxazoline rings are directly bonded to each other, compounds in which two oxazoline rings are bonded via an organic group, or compounds having three oxazoline rings. be done.
  • Examples of compounds in which two oxazoline rings are directly bonded to each other include 2,2'-bis(2-oxazoline) and 2,2'-bis-4-benzyl-2-oxazoline.
  • Compounds in which two oxazoline rings are bonded via an organic group include 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, 1,3-bis(4,5-dihydro-2- oxazolyl)benzene, 2,6-bis(isopropyl-2-oxazolin-2-yl)pyridine, 2,2'-methylenebis(4-tert-butyl-2-oxazoline), 2,2'-methylenebis(4-phenyl -2-oxazoline) and the like.
  • Compounds having three oxazoline rings include 1,2,4-tris-(2-oxazoline-2-yl)benzene and the like.
  • the polymer oxazoline compound includes, for example, an oxazoline ring-containing acrylic polymer having an oxazoline ring at the end of a side chain and polymerized with at least an acrylic acid ester.
  • the oxazoline ring-containing acrylic polymer is a polymer compound obtained by polymerizing an acrylic acid ester monomer having an oxazoline ring as at least one of the monomers.
  • Such oxazoline ring-containing acrylic polymers may be homopolymers or copolymers.
  • oxazoline ring-containing acrylic polymer for example, the product name "Epocross WS” series (manufactured by Nippon Shokubai Co., Ltd.), “Epocross K-2000” series (manufactured by Nippon Shokubai Co., Ltd.), and the like can be used.
  • the monovalent group bonded to the carbon atoms constituting the oxazoline ring is preferably only a hydrogen atom (--H) as shown in formula (2) below.
  • oxazoline compound a high molecular weight oxazoline compound is preferable in terms of better reactivity with the polyimide precursor and better storage stability of the cured product after the curing treatment.
  • An oxazoline ring-containing acrylic polymer having an oxazoline ring at the end of is more preferable.
  • the oxazoline group content (oxazoline ring content) of the oxazoline compound is preferably 1 [mmol/g] or more and 10 [mmol/g] or less, more preferably 3 [mmol/g] or more.
  • the amount of oxazoline groups in the high-molecular-weight oxazoline compound can be calculated based on the quantitative ratio between the monomer unit having an oxazoline group and other monomer units constituting the high-molecular-weight oxazoline compound. Such a ratio can be determined, for example, based on the peak intensity derived from the oxazoline group and the peak intensity derived from other monomers in the 1 H-NMR analysis results by a nuclear magnetic resonance spectrometer (NMR). can.
  • oxazoline compound one type may be employed alone, or two or more types may be employed in combination.
  • the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
  • the amount of the oxazoline ring may be 0.30 mol or more, 0.35 mol or more, or 0.39 mol or more.
  • the amount of the oxazoline ring may be 1.50 mol or less, or may be 1.20 mol or less.
  • the polyimide precursor is preferably a partial hydrolyzate of a polyimide resin
  • the oxazoline compound is a polymeric oxazoline compound (for example, a oxazoline ring-containing acrylic polymer).
  • Partially hydrolyzed polyimide precursors have a higher amount of low-molecular-weight compounds than polyimide precursors composed of monomers, and therefore may be hard and brittle when cured.
  • the curable composition of the present embodiment further contains a high-molecular-weight oxazoline compound, the physical properties of being hard and brittle can be suppressed. Therefore, the adhesion of the cured product to the adherend can be improved.
  • the curable composition of the present embodiment preferably contains 5 parts by mass or more and 95 parts by mass or less of the oxazoline compound with respect to 100 parts by mass of the polyimide precursor.
  • the curable composition of the present embodiment may contain 8 parts by mass or more, or 10 parts by mass or more of the oxazoline compound based on 100 parts by mass of the polyimide precursor.
  • the curable composition of the present embodiment may contain 90 parts by mass or less, 80 parts by mass or less, or 70 parts by mass or less of the oxazoline compound with respect to 100 parts by mass of the polyimide precursor.
  • the curable composition of this embodiment may contain a solvent.
  • Solvents include non-polar solvents and polar solvents. Examples of non-polar solvents include hydrocarbon solvents containing only carbon atoms and hydrogen atoms in the molecule, chlorine solvents such as carbon tetrachloride, and the like.
  • the curable composition of the present embodiment preferably contains a polar solvent for dissolving both the polyimide precursor and the oxazoline compound.
  • a polar solvent is a compound that also contains atoms other than carbon atoms and hydrogen atoms (eg, oxygen atoms, nitrogen atoms) in the molecule.
  • both the polyimide precursor and the oxazoline compound are dissolved in a polar solvent.
  • Polar solvents include amine solvents, amide solvents, ketone solvents, ether solvents, pyrrolidone solvents, glycol ether solvents, ester solvents, alcohol solvents, polyhydric alcohol solvents, halogen solvents, water, etc. is mentioned.
  • amine-based solvents examples include ammonia (water), diethylamine, ethylethanolamine, diethanolamine, triethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, triethylamine, tributylamine, dimethylaminoethanol, diethylaminoethanol, and methylethanol.
  • amide solvents examples include N,N-dimethylformamide and N,N-dimethylacetamide.
  • Ketone solvents include, for example, methyl ethyl ketone, methyl isobutyl ketone, ⁇ -butyrolactone, cyclohexanone, cyclopentanone and the like.
  • ether solvents include tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, methylphenyl ether and the like.
  • pyrrolidone-based solvents include N-methyl-2-pyrrolidone and the like.
  • Glycol ether solvents include, for example, methyldiglyme, ethyldiglyme, methyltriglyme, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, 1-methoxy-2-propanol, ethylene glycol monoethyl ether, etc. Or those acetates etc. are mentioned.
  • ester solvents include ethyl acetate, butyl acetate, isopropyl acetate and the like.
  • alcohol solvents examples include methyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol and the like.
  • polyhydric alcohol solvents examples include glycerin.
  • halogen-based solvents include chloroform and dichloromethane.
  • Aqueous solvents are preferred as polar solvents.
  • Aqueous solvents are water or hydrophilic organic solvents that are soluble in water in any ratio relative to water.
  • the curable composition of the present embodiment more preferably contains an aqueous solvent among polar solvents, and more preferably contains at least water as an aqueous solvent.
  • hydrophilic organic solvents examples include amine solvents such as dimethylaminoethanol and diethanolamine, amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone, Alcohol solvents such as methyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether , 1-methoxy-2-propanol and propylene glycol monomethyl ether, and polyhydric alcohol solvents such as glycerin.
  • amine solvents such as dimethylaminoethanol and diethanolamine
  • amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide
  • pyrrolidone solvents such as N-methyl-2-pyr
  • Amine-based solvents have a high affinity for polyimide precursors and cured products of such polyimide precursors. Therefore, for the purpose of improving the solubility of the polyimide precursor in the curable composition, or for the purpose of forming a nearly uniform cured product, it is preferable that the curable composition contains an amine solvent.
  • dimethylaminoethanol and diethanolamine as amine-based solvents have relatively high boiling points, so they gradually volatilize when the curable composition is subjected to curing treatment by heating. As a result, the cured product in which curing has progressed can form a more uniform cured film.
  • a plurality of types of the above polar solvents may be used in combination.
  • the above aqueous solvents may also be used in combination of multiple types.
  • the curable composition of the present embodiment may contain 60% by mass or more of a polar solvent (particularly an aqueous solvent). Moreover, a polar solvent (especially an aqueous solvent) may be included in an amount of 99% by mass or less.
  • the total weight ratio of the polyimide precursor and the oxazoline compound may be 1% by weight or more. Moreover, such a ratio may be 40% by mass or less.
  • the above curing composition includes an imidization reaction catalyst, a surfactant, an antioxidant, a leveling agent, an antistatic agent, a dye or pigment, a viscosity modifier, an antifoaming agent, a stabilizer,
  • a resin other than the polyimide resin or a coupling agent may be further included.
  • the other resins include acrylic resins, fluorine resins, epoxy resins, phenol resins, silicone resins, olefin resins, polyester resins, polyamide resins, and hydrocarbon resins. These components can be blended for the purpose of improving good workability during application of the curable composition, or improving various properties of the cured product that has undergone curing treatment.
  • the properties of the curable composition of the present embodiment are not particularly limited, but are liquid, for example.
  • the curable composition of the present embodiment may be solid.
  • the curable composition of the present embodiment can be produced, for example, by mixing the above polyimide precursor, the oxazoline compound, and, if necessary, the above polar solvent.
  • a polyimide precursor can be obtained by partially hydrolyzing a polyimide resin.
  • a method for producing such a curable composition includes, for example, A hydrolysis step of preparing a polyimide precursor by hydrolyzing a polyimide resin in the presence of water and an alkaline compound; A curable composition is prepared by mixing the polyimide precursor and the oxazoline compound so that the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor. and a mixing step.
  • the polyimide resin before hydrolysis is not particularly limited as long as it produces the polyimide precursor represented by the above general formula (1), for example.
  • Specific examples of the molecular structure of the polyimide resin are shown in formulas (A) to (J) in FIG.
  • polyimide resin partially hydrolyzed in the hydrolysis step for example, discarded polyimide resin can be used.
  • polyimide resin molded articles, more specifically polyimide resin film waste, and the like can be used.
  • the polyimide resin can be hydrolyzed under temperature conditions of, for example, 50° C. or higher and 100° C. or lower.
  • the duration of the hydrolysis treatment is, for example, 1 hour or more and 24 hours or less.
  • sodium hydroxide or potassium hydroxide is used as an alkaline compound.
  • the hydrolysis treatment may be continued until the molecular weight of the polyimide precursor reaches the above-mentioned predetermined range. Further, for example, the hydrolysis treatment may be continued until the ratio of the heights of the absorption peaks in the infrared spectroscopy spectrum obtained by infrared absorption analysis of the polyimide precursor falls within the above-described predetermined range.
  • the hydrolysis treatment can be performed until the weight average molecular weight of the polyimide precursor reaches 1,000 or more and 100,000 or less. Further, in the hydrolysis step, for example, the hydrolysis treatment can be performed until the Mw/Mn of the polyimide precursor obtained by the GPC measurement described above becomes 1 or more and 4 or less.
  • the hydrolysis treatment in the infrared spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm due to the benzene ring to the height of the absorption peak P2 due to the imide group at a wave number of 1375 cm -1 ( The hydrolysis treatment can be carried out until P1/P2) becomes 2 or more and 10 or less.
  • the hydrolysis step in the infrared spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P3 at a wave number of 1600 cm -1 due to the amide group ( The hydrolysis treatment can be carried out until P1/P3) becomes 2 or more and 20 or less.
  • the hydrolysis treatment in the infrared spectroscopic spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P4 at a wave number of 1413 cm -1 due to the carboxy group ( The hydrolysis treatment can be carried out until P1/P4) becomes 2 or more and 20 or less.
  • the next mixing step may be performed with the polyimide precursor dissolved.
  • the solvent used in the hydrolysis treatment may be volatilized by drying treatment or the like.
  • the polyimide precursor obtained by the hydrolysis treatment as described above is represented, for example, by the following formula (3).
  • the polyimide precursor represented by formula (3) has a structural unit a and a structural unit b in its molecule.
  • Structural unit a has a portion where the imide group is hydrolyzed (a portion where the cyclic imide structure becomes an amic acid structure).
  • Structural unit b has a portion in which the imide group is not hydrolyzed and remains.
  • structural unit a (left portion) and structural unit b (right portion) correspond to the repeating structural units described above.
  • the polyimide precursor may have two carboxy groups at the terminal of the molecular chain. These carboxy groups can be generated by complete hydrolysis of the cyclic imide structure by hydrolysis treatment.
  • the hydrolysis step by increasing the temperature or increasing the pH of the reaction solution (making the reaction solution more alkaline), the weight average molecular weight of the polyimide precursor can be reduced, and the amic acid in the polyimide precursor The proportion of structure can be increased.
  • the aforementioned Mw/Mn can be reduced by lengthening the hydrolysis reaction time in the hydrolysis step.
  • the mixing step for example, the powdery polyimide precursor prepared as described above, the oxazoline compound, and the solvent are mixed.
  • a common device can be used for mixing. If necessary, they may be mixed and stirred while being heated.
  • the polyimide precursor and the oxazoline compound are mixed so that the oxazoline compound has a specific amount ratio as described above with respect to 100 parts by mass of the polyimide precursor.
  • the curable composition may be produced by mixing the powdery polyimide precursor and an aqueous solution in which the oxazoline compound is dissolved. It is preferable to dissolve the polyimide precursor and the oxazoline compound in the solvent in the mixing step to prepare a curable composition in the form of a solution, and more preferably to prepare the curable composition in the form of an aqueous solution. Due to the fact that the curable composition is in the form of a solution (particularly in the form of an aqueous solution), the curable composition can be applied in various ways. Therefore, there is an advantage that the application range of the curable composition is widened. In addition, since the curable composition is an aqueous solution, it is not flammable, so there is an advantage that safety is enhanced.
  • the curable composition described above is used by being applied to an adherend such as an electric wire, film, flexible circuit board, or semiconductor.
  • the applied curable composition is subjected to a curing treatment such as heating to form a cured product (specifically, a cured resin or the like).
  • the above-mentioned curing composition is, for example, a curing composition for fiber coating, a curing composition for resin film coating, a curing composition for resin molding coating, or a curing composition for metal coating may be either
  • the above-mentioned curable composition that becomes a cured product e.g., cured resin molded article
  • is used for example, as a film, as a paint, as an electrical insulating material, as a heat-resistant component, as a heat-resistant container, as a fiber, etc. may be used in
  • the method of using the curable composition is not particularly limited.
  • the above-described curing composition is applied onto an object to be coated (an adherend such as a substrate), or impregnated into the object and then cured to obtain a cured product. (such as a cured coating film) can be formed.
  • an adherend such as a substrate
  • a cured coating film can be formed.
  • general application methods such as spray coating, dip coating, spin coating, die coating, and gravure coating can be used.
  • the solvent contained in the curable composition can be volatilized by subjecting the curable composition applied to the substrate and the substrate to heat treatment.
  • the heat treatment is not particularly limited, and general methods such as hot air heat treatment and infrared heat treatment can be employed.
  • the heating conditions for the heat treatment are, for example, 60° C. to 100° C. for 30 minutes.
  • a heat treatment can then be performed at a higher temperature to further promote thermosetting.
  • Such a heat treatment at a higher temperature is not particularly limited, either, and can be carried out by a general method.
  • the temperature condition for the heat treatment at high temperature may be 200°C or higher, preferably 300°C to 400°C.
  • the heating time may be 10 minutes to 5 hours, preferably 10 to 60 minutes.
  • the heat treatment can be performed under an inert gas atmosphere or under reduced pressure conditions.
  • curable composition and cured product of the present invention are as exemplified above, but the present invention is not limited to the above-exemplified embodiments. Moreover, in the present invention, various forms employed in general curable compositions and the like can be employed as long as the effects of the present invention are not impaired.
  • Matters disclosed by this specification include the following. (1) A polyimide precursor in which a part of the imide bond of the polyimide resin is hydrolyzed, and an oxazoline compound having an oxazoline ring in the molecule, A curable composition, wherein the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor. (2) The curable composition according to (1) above, wherein the oxazoline compound is either a low-molecular-weight oxazoline compound having a molecular weight of less than 1,000 or a high-molecular-weight oxazoline compound having a molecular weight of 1,000 or more.
  • the polyimide precursor has a benzene ring in the molecule
  • An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm ⁇ 1 due to a benzene ring and an absorption peak P2 at a wave number of 1375 cm ⁇ 1 due to an imide group
  • the curable composition according to any one of (1) to (6) above, wherein the ratio (P1/P2) of the height of the absorption peak P1 to the height of the absorption peak P2 is 2 or more and 10 or less.
  • the polyimide precursor has a benzene ring in the molecule
  • An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm ⁇ 1 due to a benzene ring and an absorption peak P3 at a wave number of 1600 cm ⁇ 1 due to an amide group
  • the curable composition according to any one of (1) to (7) above, wherein the ratio (P1/P3) of the height of the absorption peak P1 to the height of the absorption peak P3 is 2 or more and 20 or less.
  • the polyimide precursor has a benzene ring in the molecule
  • An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm ⁇ 1 due to a benzene ring and an absorption peak P4 at a wave number of 1413 cm ⁇ 1 due to a carboxy group
  • the curable composition according to any one of (1) to (8) above, wherein the ratio (P1/P4) of the height of the absorption peak P1 to the height of the absorption peak P4 is 2 or more and 20 or less.
  • the above (1) which is any one of a curing composition for fiber coating, a curing composition for resin film coating, a curing composition for resin molding coating, or a curing composition for metal coating.
  • the curable composition according to any one of (9).
  • (11) A cured product obtained by curing the curable composition according to any one of (1) to (10) above.
  • (12) The cured product according to (11) above, which is used for film applications, paint applications, electrical insulating material applications, heat-resistant parts applications, heat-resistant container applications, or fiber applications.
  • (13) A curable composition for forming a cured product by applying the curable composition described in any one of the above (1) to (10) onto an object to be coated or impregnating the object and then curing the composition. how to use things.
  • an alkaline aqueous solution was prepared by dissolving 40 g of potassium hydroxide in 600 g of deionized water in a 1000 mL vessel equipped with a stirrer. 100 g of pulverized polyimide resin was added to this alkaline aqueous solution, and hydrolysis treatment was carried out at 80 to 90° C. for 3 hours to obtain a crude polyimide precursor solution. Subsequently, the crude polyimide precursor solution was neutralized to obtain a deposit. The precipitate was filtered and washed with deionized water. Furthermore, after removing neutralized salt compounds and excess acidic compounds, drying treatment was performed. In addition, pulverization treatment was performed so as to form a powder.
  • FIG. 2 shows a GPC chart when the polyimide precursor (A-1), which is a hydrolyzate of the polyimide resin, was measured under the above-described gel permeation chromatography (GPC) measurement conditions.
  • GPC gel permeation chromatography
  • FIG. 3 shows an infrared spectroscopic spectrum (IR chart) when the polyimide resin before hydrolysis of the polyimide precursor (A-1) was subjected to infrared spectroscopic analysis under the analysis conditions and analysis method described above.
  • FIG. 4 shows an infrared spectrum (IR chart) obtained by similarly analyzing the polyimide resin before hydrolysis of the polyimide precursor (A-3).
  • FIG. 5 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-1), which is a hydrolyzate of the polyimide resin, was subjected to infrared spectroscopic analysis under the analysis conditions and analysis method described above.
  • FIG. 6 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-2), which is a hydrolyzate of the polyimide resin, was similarly analyzed.
  • FIG. 7 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-3), which is a hydrolyzate of the polyimide resin, was similarly analyzed.
  • Example 1 (Examples 1 to 9, Comparative Examples 1 to 13)
  • the above raw materials were mixed in the amounts shown in the following tables, and (A-1) was dissolved to prepare the curable compositions of Examples and Comparative Examples.
  • Table 1 shows the composition of each curing composition.
  • Each curable composition was produced such that the total amount (solid content) of (A) and (B) was about 20% by mass. Specifically, 68.1 g of ion-exchanged water and 11.6 g of diethanolamine were placed in a container equipped with a stirrer and heated to 60°C. Next, 20 g of the polyimide precursor (A) was added and stirred for 60 minutes.
  • ⁇ Uniformity of cured coating> The curable composition of each example and each comparative example was applied onto an aluminum foil (manufactured by UACJ Foil Corporation) using a bar coater. After coating, the composition was pre-dried at 60° C. for 30 minutes, and then cured by heating at 300° C. for 30 minutes to prepare a cured coating film (cured product) having a thickness of 20 ⁇ m. The uniformity of the cured coating was determined by visual observation. Good ( ⁇ ): Brown transparent film Somewhat good ( ⁇ ): Slightly cloudy Poor ( ⁇ ): Cloudy
  • Adhesion of cured coating The adhesiveness of the cured coating film of each example and each comparative example was measured by making cuts in a grid pattern with a cutter knife and performing a peeling operation with the adhesive tape. The measurement was carried out according to JIS K5600-5-6:1999 General Test Methods for Paints, Part 5: Mechanical properties of coating film, Section 6: Adhesion (cross-cut method, so-called cross-cut test). A polyimide film and SUS were used as adherends. Adhesion was evaluated according to the following criteria. Good ( ⁇ ): Remaining number is 90 to 100/100 Somewhat good ( ⁇ ): The number of remaining is 50 to 90/100 Defective (x): Remaining number is 0 to 50/100
  • Table 2 shows the results of evaluating each of the above performances for each curing composition. It was confirmed that the uniformity of the cured coating films of Comparative Examples 4 to 7 was not good, so other evaluations (flexibility and adhesion) were not performed.
  • the reason why the cured product (cured coating film) of the curable composition of the example can exhibit good performance is considered as follows.
  • a curing treatment such as heating, at least part of the plurality of amic acid structures in the polyimide precursor is imidized.
  • a new cyclic polyimide structure is formed.
  • the carboxy group in the amic acid structure of a portion of the polyimide precursor and the carboxy group at the molecular chain end of the polyimide precursor can form an amide ester bond with the oxazoline ring of the oxazoline compound.
  • the polyimide precursor and a relatively large amount of the oxazoline compound can be bonded.
  • the cured product (cured resin, cured coating film, etc.) obtained by curing the curable composition is , can exhibit good adhesion to the adherend. Moreover, cracking of the cured product can be suppressed, and the cured product can have flexibility. In addition, the cured product is also excellent in terms of uniformity.
  • the cured coating films obtained by curing the curable compositions of Examples have good uniformity and good adhesion to adherends. , and was also good in terms of bendability (that is, flexibility). That is, the cured coating film obtained by curing the curable composition of the example had uniformity, flexibility, and adhesion to the adherend at the same time.
  • a curable composition that does not contain an oxazoline compound or a curable composition that contains less than a specific amount of an oxazoline compound the internal stress of the cured coating film cured by the curing treatment cannot be relaxed, and the adhesion of the cured coating film is reduced. This is thought to be due to the lower flexibility and flexibility.
  • each curing composition containing the above-mentioned polyimide precursors (A-2) and (A-3) shown as a reference can also form a good cured coating film.
  • the curable composition of the present invention is applied to, for example, metals, resin moldings, fibers, and films in order to produce cured products having properties such as heat resistance, electrical insulation, and chemical resistance. be.

Abstract

Provided are a curable composition and the like that include a polyimide precursor in which some of the imide bonds of a polyimide resin are hydrolyzed and an oxazoline compound having an oxazoline ring in the molecule thereof, and in which the quantity of oxazoline rings of the oxazoline compound relative to 1 mol of a repeating structural unit of the polyamide precursor is 0.20-1.60 mol.

Description

硬化用組成物及び硬化物Curing composition and cured product 関連出願の相互参照Cross-reference to related applications
　本願は、日本国特願２０２１－０６６６１１号の優先権を主張し、該出願が引用によって本願明細書の記載に組み込まれる。 This application claims priority from Japanese Patent Application No. 2021-066611, which is incorporated herein by reference.
　本発明は、例えば、硬化処理によって硬化物となる硬化用組成物、及び、該硬化用組成物が硬化した硬化物に関する。 The present invention relates to, for example, a curable composition that becomes a cured product by curing treatment, and a cured product obtained by curing the curable composition.
　従来、硬化処理によって硬化する硬化用組成物として、例えば、ポリイミド樹脂のイミド結合の一部が加水分解されたポリイミド前駆体を少なくとも含む硬化用組成物が知られている。
　この種の硬化用組成物において、ポリイミド前駆体は、複数の環状イミド構造と、イミド化反応によって環状イミド構造を形成できる複数のアミック酸構造（カルボキシ基及びアミド基）とを分子中に有する。この種の硬化用組成物は、硬化処理されることによって、ポリイミド前駆体中のアミック酸構造がイミド化（脱水縮合反応）してイミド結合を形成し、これにより硬化物を生成する。生成した硬化物が耐熱性及び電気絶縁性などを有することから、この種の硬化用組成物は、例えば絶縁被覆材といった硬化物を硬化処理によって形成させるために使用される。 Conventionally, as a curable composition that is cured by a curing treatment, for example, a curable composition containing at least a polyimide precursor obtained by partially hydrolyzing the imide bonds of a polyimide resin is known.
In this type of curable composition, the polyimide precursor has in its molecule a plurality of cyclic imide structures and a plurality of amic acid structures (carboxy groups and amide groups) capable of forming cyclic imide structures by imidization reaction. When this type of curable composition is cured, the amic acid structure in the polyimide precursor is imidized (dehydration condensation reaction) to form an imide bond, thereby producing a cured product. Since the resulting cured product has heat resistance, electrical insulation, etc., this type of curable composition is used to form a cured product such as an insulating coating material by a curing treatment.
　上記のごとき硬化用組成物としては、例えば、ポリイミド成形品を部分的に加水分解してなるイミド基含有化合物（ポリイミド前駆体）と、エポキシ化合物と、ブロック型イソシアネート化合物と、を含む硬化用組成物であって、ポリイミド前駆体１００質量部に対して、エポキシ化合物の配合量を１０～１００質量部の範囲内の値とし、ブロック型イソシアネート化合物の配合量を１０～１００質量部の範囲内の値とし、かつ、１２０℃×６０分の加熱条件で硬化させた場合に、熱天秤で測定される１０質量％減少温度が、２００℃以上の値となる、硬化用組成物が知られている（特許文献１）。
　特許文献１に記載された硬化用組成物は、比較的低温の硬化処理によって硬化でき、被着体に対する硬化物の接着性（密着性）を良好にでき、硬化物の耐熱性を良好にできる。 Examples of the curable composition as described above include an imide group-containing compound (polyimide precursor) obtained by partially hydrolyzing a polyimide molded article, an epoxy compound, and a blocked isocyanate compound. A product, with respect to 100 parts by mass of the polyimide precursor, the amount of the epoxy compound is set to a value within the range of 10 to 100 parts by mass, and the amount of the blocked isocyanate compound is set to a value within the range of 10 to 100 parts by mass. and when cured under heating conditions of 120 ° C. x 60 minutes, the 10 mass% reduction temperature measured with a thermobalance is a value of 200 ° C. or higher. (Patent Document 1).
The curable composition described in Patent Document 1 can be cured by a relatively low-temperature curing treatment, can improve the adhesion (adhesion) of the cured product to the adherend, and can improve the heat resistance of the cured product. .
　また、上記のごとき硬化用組成物としては、例えば、ポリイミド成形品を部分的に加水分解したイミド基含有化合物（ポリイミド前駆体）と、水性溶媒と、沸点が８５～１４５℃であるアミン化合物と、を含む硬化用組成物であって、イミド基含有化合物が、赤外分光チャートにおいて、ベンゼン環に由来した波数１５００ｃｍ－１における吸収ピークと、イミド基に由来した波数１３７５ｃｍ－１の吸収ピークと、を有し、ベンゼン環に由来した波数１５００ｃｍ－１における吸収ピークの高さをＳ１とし、イミド基に由来した波数１３７５ｃｍ－１の吸収ピークの高さをＳ２としたときに、Ｓ１／Ｓ２の比率が２～１０の範囲内の値である、硬化用組成物が知られている（特許文献２）。
　特許文献２に記載された硬化用組成物は、水などの水性溶媒を含みつつ安定性が良好であり、また、比較的低温の硬化処理によって硬化できる。 Further, as the above-mentioned curing composition, for example, an imide group-containing compound (polyimide precursor) obtained by partially hydrolyzing a polyimide molded article, an aqueous solvent, and an amine compound having a boiling point of 85 to 145 ° C. , wherein the imide group-containing compound has an absorption peak at a wave number of 1500 cm -1 derived from the benzene ring and an absorption peak at a wave number of 1375 cm -1 derived from the imide group in the infrared spectroscopy chart. , When the height of the absorption peak at a wave number of 1500 cm −1 derived from a benzene ring is S1 and the height of an absorption peak at a wave number of 1375 cm −1 derived from an imide group is S2, the ratio of S1/S2 A curable composition having a ratio in the range of 2 to 10 is known (Patent Document 2).
The curable composition described in Patent Document 2 has good stability while containing an aqueous solvent such as water, and can be cured by a relatively low-temperature curing treatment.
日本国特開２０１７－０１４３８６号公報Japanese Patent Application Laid-Open No. 2017-014386 日本国特許第６４０２２８３号公報Japanese Patent No. 6402283
　しかしながら、特許文献１に記載の硬化用組成物に硬化処理を施しても、生成された硬化物が、必ずしも良好な均一性を有しない。また、特許文献２の硬化用組成物に硬化処理を施しても、生成された硬化物が、必ずしも良好な柔軟性を有しない。
　このように、上述した硬化用組成物が硬化処理されて生成した硬化物は、均一性、柔軟性、及び、被着体への密着性といった性能を兼ね備えることが困難である。
　そこで、均一性と、柔軟性と、被着体に対する密着性と、を兼ね備えた硬化物を生成できる硬化用組成物が要望されている。 However, even if the curable composition described in Patent Document 1 is subjected to a curing treatment, the resulting cured product does not necessarily have good uniformity. Further, even if the curable composition of Patent Document 2 is subjected to a curing treatment, the resulting cured product does not necessarily have good flexibility.
Thus, it is difficult for the cured product produced by curing the above-described curable composition to have properties such as uniformity, flexibility, and adhesion to adherends.
Therefore, there is a demand for a curable composition capable of producing a cured product having uniformity, flexibility and adhesion to an adherend.
　本発明は、上記問題点、要望点等に鑑み、均一性と、柔軟性と、被着体に対する密着性と、を兼ね備えた硬化物を生成できる硬化用組成物を提供することを課題とする。 An object of the present invention is to provide a curable composition capable of producing a cured product having uniformity, flexibility, and adhesion to an adherend. .
　本発明に係る硬化用組成物は、ポリイミド樹脂のイミド結合の一部が加水分解されたポリイミド前駆体と、
　オキサゾリン環を分子中に有するオキサゾリン化合物とを含み、
　前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下であることを特徴とする。 The curable composition according to the present invention is a polyimide precursor in which a part of the imide bond of the polyimide resin is hydrolyzed,
and an oxazoline compound having an oxazoline ring in the molecule,
The amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
　本発明に係る硬化用組成物では、前記オキサゾリン化合物が高分子化合物であってもよい。また、本発明に係る硬化用組成物は、水性溶媒をさらに含んでもよい。
　本発明に係る硬化用組成物では、前記ポリイミド前駆体がベンゼン環を分子中に有し、前記ポリイミド前駆体を赤外分光分析した赤外分光スペクトルが、ベンゼン環による波数１５００ｃｍ－１の吸収ピークＰ１と、イミド基による波数１３７５ｃｍ－１の吸収ピークＰ２と、を示し、前記吸収ピークＰ２の高さに対する前記吸収ピークＰ１の高さの比（Ｐ１／Ｐ２）が、２以上１０以下であってもよい。 In the curable composition according to the present invention, the oxazoline compound may be a polymer compound. Moreover, the curable composition according to the present invention may further contain an aqueous solvent.
In the curable composition according to the present invention, the polyimide precursor has a benzene ring in the molecule, and the infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor has an absorption peak at a wave number of 1500 cm -1 due to the benzene ring. P1 and an absorption peak P2 at a wave number of 1375 cm −1 due to the imide group, and the ratio of the height of the absorption peak P1 to the height of the absorption peak P2 (P1/P2) is 2 or more and 10 or less good too.
　本発明に係る硬化物は、上記の硬化用組成物が硬化したものである。 The cured product according to the present invention is obtained by curing the above curable composition.
加水分解される前のポリイミド樹脂の各例の模式的分子構造式を表した図。FIG. 2 is a diagram showing a schematic molecular structural formula of each example of polyimide resin before hydrolysis. ポリイミド前駆体（加水分解物）のＧＰＣチャート図。The GPC chart figure of a polyimide precursor (hydrolyzate). 加水分解前の一例のポリイミド樹脂のＩＲチャート図。FIG. 3 is an IR chart of an example polyimide resin before hydrolysis. 加水分解前の他例のポリイミド樹脂のＩＲチャート図。IR chart figure of the polyimide resin of another example before hydrolysis. 一例のポリイミド前駆体（加水分解物）のＩＲチャート図。An IR chart of an example of a polyimide precursor (hydrolyzate). 別例のポリイミド前駆体（加水分解物）のＩＲチャート図。The IR chart figure of the polyimide precursor (hydrolyzate) of another example. 他例のポリイミド前駆体（加水分解物）のＩＲチャート図。IR chart figure of the polyimide precursor (hydrolyzate) of another example.
　本発明に係る硬化用組成物及び硬化物の実施形態について以下に説明する。 Embodiments of the curable composition and cured product according to the present invention are described below.
　本実施形態の硬化用組成物は、ポリイミド樹脂のイミド結合の一部が加水分解されたポリイミド前駆体と、
　オキサゾリン環を分子中に有するオキサゾリン化合物とを含み、
　前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下である。
　本実施形態の硬化用組成物によれば、均一性と、柔軟性と、被着体に対する密着性と、を兼ね備えた硬化物を生成できる。 The curable composition of the present embodiment includes a polyimide precursor in which a portion of the imide bond of the polyimide resin is hydrolyzed,
and an oxazoline compound having an oxazoline ring in the molecule,
The amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
According to the curable composition of the present embodiment, a cured product having uniformity, flexibility, and adhesion to an adherend can be produced.
　本実施形態において、上記のポリイミド前駆体は、複数の環状イミド構造と、複数のアミック酸構造とを分子中に有する。各アミック酸構造は、カルボキシ基及びアミド基を含む。各アミック酸構造におけるカルボキシ基とアミド基とは、加熱等の硬化処理によってイミド化（脱水縮合反応）してイミド結合（イミド基）を形成できる。斯かるイミド化によって環状イミド構造が新たに作り出される。
　アミック酸構造は、環状イミド構造を構成するイミド結合が加水分解された構造であり、環状イミド構造は、アミック酸構造におけるカルボキシ基及びアミド基がイミド化（脱水縮合反応）した構造である。
　また、上記のポリイミド前駆体は、ポリイミド樹脂の加水分解物であるため、分子鎖末端にカルボキシ基を有し得る。 In this embodiment, the polyimide precursor has multiple cyclic imide structures and multiple amic acid structures in the molecule. Each amic acid structure contains a carboxy group and an amide group. A carboxy group and an amide group in each amic acid structure can be imidized (dehydration condensation reaction) by curing treatment such as heating to form an imide bond (imide group). Such imidization creates a new cyclic imide structure.
The amic acid structure is a structure obtained by hydrolyzing the imide bond that constitutes the cyclic imide structure, and the cyclic imide structure is a structure obtained by imidization (dehydration condensation reaction) of the carboxy group and the amide group in the amic acid structure.
Moreover, since the polyimide precursor described above is a hydrolyzate of a polyimide resin, it may have a carboxy group at the molecular chain end.
　加水分解前のポリイミド樹脂としては、市販されている製品を用いることができる。ポリイミド樹脂の製品としては、例えば、製品名「カプトン」シリーズ（東レ・デュポン社製）、製品名「ユーピレックス」シリーズ（宇部興産社製）、製品名「Ａｕｒｕｍ」（三井化学社製）などを用いることができる。これらポリイミド樹脂の分子構造の具体例については、後に詳述する（図１を参照）。
　加水分解前のポリイミド樹脂としては、地球環境保護の観点から、従来廃棄されていたポリイミド樹脂フィルム等を加水分解したポリイミド前駆体を用いることが好ましい。これにより、ポリイミド樹脂のリサイクルを活発にすることができ、しかも、均一性と、柔軟性と、被着体に対する密着性と、を兼ね備えた硬化物を生成できる。 A commercially available product can be used as the polyimide resin before hydrolysis. Examples of polyimide resin products include the product name “Kapton” series (manufactured by Toray DuPont), the product name “Upilex” series (manufactured by Ube Industries, Ltd.), and the product name “Aurum” (manufactured by Mitsui Chemicals, Inc.). be able to. Specific examples of the molecular structures of these polyimide resins will be described in detail later (see FIG. 1).
As the polyimide resin before hydrolysis, it is preferable to use a polyimide precursor obtained by hydrolyzing a polyimide resin film or the like, which has conventionally been discarded, from the viewpoint of protecting the global environment. As a result, the polyimide resin can be recycled more actively, and a cured product having uniformity, flexibility, and adhesion to the adherend can be produced.
　上記のポリイミド前駆体は、例えば、下記一般式（１）で示される分子構造を有する。一般式（１）において、Ａｒは、例えば芳香族構造、環状飽和炭化水素構造、直鎖状若しくは分岐鎖状の飽和炭化水素構造、又は、エーテル基などの少なくともいずれかを含んでもよい。一方、Ａｒ’は、例えば芳香族構造、環状飽和炭化水素構造、若しくは分岐鎖状の飽和炭化水素構造、又は、エーテル基などの少なくともいずれかを含んでもよい。なお、一般式（１）において、ｍ及びｎは、それぞれ、分子中における比を表し（ｍ＋ｎ＝１０）、例えばｍが５以上９以下であり、ｎが１以上５以下であってもよい。 The above polyimide precursor has, for example, a molecular structure represented by the following general formula (1). In general formula (1), Ar may include at least one of an aromatic structure, a cyclic saturated hydrocarbon structure, a linear or branched saturated hydrocarbon structure, an ether group, and the like. On the other hand, Ar' may contain at least one of, for example, an aromatic structure, a cyclic saturated hydrocarbon structure, a branched saturated hydrocarbon structure, an ether group, and the like. In general formula (1), m and n each represent a ratio in the molecule (m+n=10). For example, m may be 5 or more and 9 or less, and n may be 1 or more and 5 or less.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　上記のポリイミド前駆体における繰り返し構造単位は、加水分解される前のポリイミド樹脂における繰り返し構造単位に相当する。詳しくは、加水分解前のポリイミド樹脂は、ジアミンモノマーとテトラカルボン酸（二無水物）モノマーとが反応した生成物の構造単位が分子中で繰り返された構成を有する。上記のポリイミド前駆体も、同様の繰り返し構造単位を分子中に有する。ただし、加水分解によって生じたポリイミド前駆体では、環状イミド構造の一部が加水分解によってアミック酸構造となっているため、一般式（１）の左側における括弧内の部分も、一般式（１）の右側における括弧内の部分も、それぞれ繰り返し構造単位である。
　例えば、上記の繰り返し構造単位のモル数は、以下のようにして算出できる。加水分解される前のポリイミド樹脂の繰り返し構造単位は、例えば上記一般式（１）の右側における括弧内の部分である。そのポリイミド樹脂の質量を、右側括弧内部分の分子量で割る（除する）ことによって、繰り返し構造単位のモル数を算出できる。
　なお、上記の繰り返し構造単位における窒素原子数は２である。そのため、前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量は、前記ポリイミド前駆体中の窒素原子２ｍｏｌあたりの量として表すこともできる。 The repeating structural unit in the above polyimide precursor corresponds to the repeating structural unit in the polyimide resin before hydrolysis. Specifically, the polyimide resin before hydrolysis has a structure in which structural units of a reaction product of a diamine monomer and a tetracarboxylic acid (dianhydride) monomer are repeated in the molecule. The above polyimide precursor also has similar repeating structural units in its molecule. However, in the polyimide precursor produced by hydrolysis, part of the cyclic imide structure is hydrolyzed to an amic acid structure, so the part in parentheses on the left side of general formula (1) is also represented by general formula (1) The parts in parentheses on the right side of are also repeating structural units.
For example, the number of moles of the repeating structural unit can be calculated as follows. The repeating structural unit of the polyimide resin before hydrolysis is, for example, the portion in parentheses on the right side of the general formula (1). The number of moles of the repeating structural unit can be calculated by dividing (dividing) the mass of the polyimide resin by the molecular weight of the portion inside the right parenthesis.
The number of nitrogen atoms in the repeating structural unit is two. Therefore, the amount of the oxazoline ring of the oxazoline compound with respect to 1 mol of the repeating structural unit of the polyimide precursor can also be expressed as the amount per 2 mol of nitrogen atoms in the polyimide precursor.
　上述したように、上記のポリイミド前駆体は、ポリイミド樹脂における複数のイミド結合の一部が加水分解された加水分解物であるため、上記のポリイミド前駆体は、一般式（１）の左側で表されるアミック酸構造（βで示される部分）と、右側で表される環状ポリイミド構造（αで示される部分）の両方を分子中に有する。 As described above, the above polyimide precursor is a hydrolyzate obtained by partially hydrolyzing a plurality of imide bonds in the polyimide resin, so the above polyimide precursor is represented on the left side of general formula (1) The molecule has both the amic acid structure (portion indicated by β) shown on the right side and the cyclic polyimide structure (portion indicated by α) shown on the right side.
　上記のポリイミド前駆体は、分子中に芳香族構造（特にベンゼン環構造）を有することが好ましい。ポリイミド前駆体が分子中にベンゼン環構造を有することにより、硬化物がより高い耐熱性を発揮できるという利点がある。 The above polyimide precursor preferably has an aromatic structure (particularly a benzene ring structure) in its molecule. By having a benzene ring structure in the molecule of the polyimide precursor, there is an advantage that the cured product can exhibit higher heat resistance.
　上記のポリイミド前駆体の分子中において、１つのベンゼン環に対する窒素原子数のモル比は、０．２以上１．０以下であってもよく、０．４以上０．８以下であってもよい。斯かるモル比は、後述する赤外分光分析、又は、ＮＭＲ測定などによって分析できる。 In the molecule of the above polyimide precursor, the molar ratio of the number of nitrogen atoms to one benzene ring may be 0.2 or more and 1.0 or less, or 0.4 or more and 0.8 or less. . Such a molar ratio can be analyzed by infrared spectroscopic analysis, NMR measurement, or the like, which will be described later.
　一般式（１）において、例えば下記に示すように、ＡｒがＡｒ－１（ベンゼン環を１つ有する構造）又はＡｒ－２（ベンゼン環を２つ有する構造）であってもよい。また、Ａｒ’がＡｒ’－１（ベンゼン環を２つ有する構造）又はＡｒ’－２（ベンゼン環を１つ有する構造）であってもよい。
　一般式（１）において、ＡｒがＡｒ－１（ベンゼン環を１つ有する）であり且つＡｒ’がＡｒ’－１（ベンゼン環を２つ有する）であってもよい。
Figure JPOXMLDOC01-appb-C000002
 In general formula (1), for example, Ar may be Ar-1 (structure having one benzene ring) or Ar-2 (structure having two benzene rings), as shown below. Ar' may be Ar'-1 (structure having two benzene rings) or Ar'-2 (structure having one benzene ring).
In general formula (1), Ar may be Ar-1 (having one benzene ring) and Ar' may be Ar'-1 (having two benzene rings).
Figure JPOXMLDOC01-appb-C000002
　本実施形態のポリイミド前駆体は、ポリイミド樹脂の加水分解反応生成物である。上記のポリイミド前駆体の製造方法については、後に詳述する。 The polyimide precursor of this embodiment is a hydrolysis reaction product of polyimide resin. The method for producing the above polyimide precursor will be described in detail later.
　ポリイミド前駆体の平均分子量（質量平均分子量）は、例えば１，０００以上１００，０００以下であってもよい。ポリイミド前駆体の平均分子量（質量平均分子量）は、３，０００以上であることが好ましく、５，０００以上であることがより好ましい。斯かる平均分子量（質量平均分子量）は、６０，０００以下であることが好ましく、３０，０００以下であることがより好ましい。ポリイミド前駆体の質量平均分子量が上記のごとき範囲内であることによって、後述する溶媒に対する溶解性がより良好となる。 The average molecular weight (mass average molecular weight) of the polyimide precursor may be, for example, 1,000 or more and 100,000 or less. The average molecular weight (weight average molecular weight) of the polyimide precursor is preferably 3,000 or more, more preferably 5,000 or more. The average molecular weight (weight average molecular weight) is preferably 60,000 or less, more preferably 30,000 or less. When the weight average molecular weight of the polyimide precursor is within the above range, the solubility in the solvent described later becomes better.
　ポリイミド前駆体の質量平均分子量は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）測定によって求められる。
　ＧＰＣ測定条件の詳細は、以下の通りである。
　　装置名：東ソー社製　製品名「ＨＬＣ－８３２０ＧＰＣ」
　　検出器：示差屈折率（ＲＩ）検出器
　　カラム：スチレンジビニルベンゼン（平均粒子径３μｍ　平均細孔径２ｎｍ）１本
　　カラム温度：４０℃
　　検量線作成のための標準物質：ポリエチレングルコール
　　データ処理ソフトウェア：上記装置に付属のソフトウェア
　　溶離液：Ｎ，Ｎ‐ジメチルアセトアミド（ＤＭＡｃ）
　　［数平均分子量（Ｍｎ）、質量平均分子量（Ｍｗ）、分子量分布（Ｍｗ／Ｍｎ）］ The mass average molecular weight of the polyimide precursor is determined by gel permeation chromatography (GPC) measurement.
Details of the GPC measurement conditions are as follows.
Device name: Tosoh product name “HLC-8320GPC”
Detector: Differential refractive index (RI) detector Column: Styrenedivinylbenzene (average particle size: 3 μm, average pore size: 2 nm) Column temperature: 40°C
Standard substance for creating a calibration curve: polyethylene glycol Data processing software: software attached to the above equipment Eluent: N,N-dimethylacetamide (DMAc)
[Number average molecular weight (Mn), mass average molecular weight (Mw), molecular weight distribution (Mw/Mn)]
　上記のＧＰＣ測定によって求められたポリイミド前駆体のＭｗ／Ｍｎは、１．０以上であることが好ましく、１．５以上であることがより好ましい。斯かるＭｗ／Ｍｎは、３．０以下であることが好ましく、２．５以下であることがより好ましい。
　ポリイミド前駆体のＭｗ／Ｍｎが１．０以上３．０以下であることによって、硬化物の物性がより均一化し、安定化するという利点がある。
　ポリイミド樹脂の加水分解反応生成物、即ち、ポリイミド樹脂が加水分解されて生じた上記のポリイミド前駆体では、Ｍｗ／Ｍｎが上記のごとき範囲となり得る。 The Mw/Mn of the polyimide precursor determined by the GPC measurement is preferably 1.0 or more, more preferably 1.5 or more. Such Mw/Mn is preferably 3.0 or less, more preferably 2.5 or less.
When the Mw/Mn of the polyimide precursor is 1.0 or more and 3.0 or less, there is an advantage that the physical properties of the cured product are made more uniform and stabilized.
In the hydrolysis reaction product of the polyimide resin, that is, in the above-described polyimide precursor produced by hydrolysis of the polyimide resin, the Mw/Mn can fall within the above range.
　ポリイミド前駆体を赤外分光分析したときの赤外分光（ＩＲ）スペクトル（チャート）において、例えば以下のような吸収ピークが確認される。例えば、ポリイミド樹脂の加水分解反応生成物、即ち、ポリイミド樹脂が加水分解されて生じたポリイミド前駆体において、以下のような吸収ピークが確認される。なお、赤外分光分析の技術分野で常識的に判断されるように、以下に示す各波数は、その波数付近における吸収ピークを規定するための数値である。換言すると、以下に示す各波数は、その波数にピーク頂点を有する吸収ピークだけを示すものではない。 In the infrared spectroscopy (IR) spectrum (chart) when the polyimide precursor is analyzed by infrared spectroscopy, for example, the following absorption peaks are confirmed. For example, the following absorption peaks are observed in a hydrolysis reaction product of a polyimide resin, that is, a polyimide precursor produced by hydrolysis of a polyimide resin. In addition, each wavenumber shown below is a numerical value for defining the absorption peak in the vicinity of the wavenumber, as is commonly judged in the technical field of infrared spectroscopic analysis. In other words, each wavenumber shown below does not represent only an absorption peak having a peak apex at that wavenumber.
　ポリイミド前駆体の赤外分光分析は、下記の測定条件で実施する。市販されている測定機器を用いて下記の測定条件にて赤外分光分析を実施できる。
装置名：フーリエ変換赤外分光光度計（日本分光社製「ＦＴ／ＩＲ－４６００」）
　　分析方法：全反射法（Attenuated Total Reflection：ＡＴＲ）
　　測定波数範囲：４０００ｃｍ－１～４００ｃｍ－１ The infrared spectroscopic analysis of the polyimide precursor is carried out under the following measurement conditions. Infrared spectroscopic analysis can be performed using a commercially available measuring instrument under the following measurement conditions.
Device name: Fourier transform infrared spectrophotometer (“FT/IR-4600” manufactured by JASCO Corporation)
Analysis method: Attenuated Total Reflection (ATR)
Measurement wavenumber range: 4000 cm -1 to 400 cm -1
・赤外分光スペクトル（ベンゼン環による吸収ピークＰ１）
　本実施形態におけるポリイミド前駆体は、赤外分光分析されたときの赤外分光スペクトルにおいて、例えば図５に示すように、波数１５００ｃｍ－１（付近）に、ベンゼン環による吸収ピークＰ１を示す。 ・Infrared spectrum (absorption peak P1 due to benzene ring)
The polyimide precursor of the present embodiment exhibits an absorption peak P1 due to a benzene ring at (near) 1500 cm -1 wavenumber in the infrared spectrum when analyzed by infrared spectroscopy, as shown in FIG. 5, for example.
・赤外分光スペクトル（イミド基による吸収ピークＰ２）
　本実施形態におけるポリイミド前駆体は、赤外分光分析されたときの赤外分光スペクトルにおいて、例えば図５に示すように、波数１３７５ｃｍ－１（付近）に、イミド基による吸収ピークＰ２を示す。
　上記ポリイミド前駆体は、イミド基を分子中に有することから、加熱などによる硬化処理によって生成した硬化物が良好な耐熱性を有する。 ・Infrared spectrum (absorption peak P2 due to imide group)
The polyimide precursor in the present embodiment exhibits an absorption peak P2 due to the imide group at (near) 1375 cm -1 wavenumber in the infrared spectroscopic spectrum when analyzed by infrared spectroscopy, as shown in FIG. 5, for example.
Since the polyimide precursor has an imide group in its molecule, a cured product produced by a curing treatment such as heating has good heat resistance.
・赤外分光スペクトル（アミド基による吸収ピークＰ３）
　本実施形態におけるポリイミド前駆体は、例えば図５に示すように、波数１６００ｃｍ－１（付近）に、アミド基（－ＮＨＣＯ－）による吸収ピークＰ３を示す。
　上記ポリイミド前駆体は、アミド基を分子中に有することから、比較的低温で硬化できる。 ・Infrared spectrum (absorption peak P3 due to amide group)
The polyimide precursor in the present embodiment exhibits an absorption peak P3 due to an amide group (-NHCO-) at (near) 1600 cm -1 wavenumber, as shown in Fig. 5, for example.
Since the polyimide precursor has an amide group in its molecule, it can be cured at a relatively low temperature.
・赤外分光スペクトル（カルボキシ基による吸収ピークＰ４）
　本実施形態におけるポリイミド前駆体は、例えば図５に示すように、波数１４１３ｃｍ－１（付近）に、カルボキシ基（－ＣＯＯＨ）による吸収ピークＰ４を示す。
　上記ポリイミド前駆体は、カルボキシ基を分子中に有することから、後述する溶媒に対して良好な溶解性を有し、また、硬化処理を経た硬化物が良好な密着性を有することができる。 ・Infrared spectroscopy spectrum (absorption peak P4 due to carboxy group)
The polyimide precursor in the present embodiment exhibits an absorption peak P4 due to a carboxy group (—COOH) at (near) 1413 cm −1 wavenumber, as shown in FIG. 5, for example.
Since the polyimide precursor has a carboxyl group in the molecule, it has good solubility in the solvent described later, and the cured product after curing treatment can have good adhesion.
・赤外分光スペクトル（カルボニル基による吸収ピークＰ５）
　本実施形態におけるポリイミド前駆体は、例えば図５に示すように、波数１７１０ｃｍ－１（付近）に、カルボニル基（－ＣＯ－）による吸収ピークＰ５を示す。
　本実施形態において、ポリイミド前駆体は、カルボニル基を分子中に有することから、後述する溶媒に対して良好な溶解性を有する。 ・Infrared spectrum (absorption peak P5 due to carbonyl group)
The polyimide precursor in this embodiment exhibits an absorption peak P5 due to a carbonyl group (—CO—) at (near) 1710 cm −1 wavenumber, as shown in FIG. 5, for example.
In the present embodiment, the polyimide precursor has a carbonyl group in its molecule, and thus has good solubility in the solvent described below.
　ポリイミド樹脂を部分的に加水分解させることによってポリイミド前駆体を得た場合、ポリイミド前駆体におけるイミド基量（吸収ピークの高さ）、アミド基量（吸収ピークの高さ）、及び、カルボキシ基量（吸収ピークの高さ）は、ポリイミド樹脂の加水分解の程度を示す指標となり得る。例えば、加水分解によっても化学構造が変化しないベンゼン環による吸収ピークの高さに対する、上記の各官能基の吸収ピークの高さを求めることで、加水分解の程度の大小を確認できる。
　換言すると、ポリイミド樹脂を部分的に加水分解させることによってポリイミド前駆体を得た場合、上記のイミド基による吸収ピークＰ２の高さ、アミド基による吸収ピークＰ３の高さ、及び、カルボキシ基による吸収ピークＰ４の高さは、それぞれ、ポリイミド樹脂の加水分解の程度を示す指標になり得る。加水分解の程度を示すより正確な指標としては、上記の高さの各比（Ｐ１／Ｐ２、Ｐ１／Ｐ３、Ｐ１／Ｐ４）が採用され得る。 When the polyimide precursor is obtained by partially hydrolyzing the polyimide resin, the imide group amount (absorption peak height), the amide group amount (absorption peak height), and the carboxy group amount in the polyimide precursor (Absorption peak height) can be an index indicating the degree of hydrolysis of the polyimide resin. For example, the degree of hydrolysis can be confirmed by determining the height of the absorption peak of each functional group with respect to the height of the absorption peak of the benzene ring whose chemical structure does not change even by hydrolysis.
In other words, when the polyimide precursor is obtained by partially hydrolyzing the polyimide resin, the height of the absorption peak P2 due to the imide group, the height of the absorption peak P3 due to the amide group, and the absorption due to the carboxy group The height of the peak P4 can be an index indicating the degree of hydrolysis of the polyimide resin. As a more accurate indicator of the degree of hydrolysis, the above height ratios (P1/P2, P1/P3, P1/P4) can be employed.
　上述した吸収ピークの高さの各比は、以下のようにして算出される。ポリイミド前駆体を赤外分光分析した結果として、横軸が波数［ｃｍ－１］、縦軸が透過率［％］（上側が透過率１００％）によって表された赤外分光スペクトル（ＩＲチャート）を用意する。１４００～１４３０ｃｍ－１付近に表れる上側に突出したピークの頂点を通る水平ラインを引き、この水平ラインをベースラインとする。そして、上記の各吸収ピークの高さ［％］と、ベースラインの高さ［％］との差の絶対値を求める。例えば、ベースラインの高さ［％］が９０［％］であり、吸収ピークＰ１の高さが７０［％］であり、吸収ピークＰ２の高さが８０［％］であった場合、吸収ピークの高さの比（Ｐ１／Ｐ２）は、下記式によって算出される。
（算出例）
　　　（Ｐ１／Ｐ２）＝（｜７０－９０｜／｜８０－９０｜）＝２．０ Each ratio of the heights of the absorption peaks described above is calculated as follows. As a result of infrared spectroscopic analysis of the polyimide precursor, the horizontal axis is the wavenumber [cm -1 ], and the vertical axis is the transmittance [%] (upper side is 100% transmittance) Infrared spectrum spectrum (IR chart). prepare. A horizontal line passing through the apex of the upwardly protruding peak appearing in the vicinity of 1400 to 1430 cm −1 is drawn, and this horizontal line is used as a baseline. Then, the absolute value of the difference between the height [%] of each absorption peak and the height [%] of the baseline is obtained. For example, the baseline height [%] is 90 [%], the height of the absorption peak P1 is 70 [%], and the height of the absorption peak P2 is 80 [%], the absorption peak The height ratio (P1/P2) of is calculated by the following formula.
(Calculation example)
(P1/P2)=(|70−90|/|80−90|)=2.0
・イミド基による吸収ピークＰ２の高さに対する、ベンゼン環による吸収ピークＰ１の高さの比：Ｐ１／Ｐ２
　本実施形態におけるポリイミド前駆体の赤外分光スペクトルにおいて、イミド基による波数１３７５ｃｍ－１の吸収ピークＰ２の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ２）は、２以上であることが好ましく、３以上であってもよい。また、斯かる比（Ｐ１／Ｐ２）は、１０以下であることが好ましく、９以下であることがより好ましく、５以下であることがより好ましい。
　上記ポリイミド前駆体は、上記の高さの比（Ｐ１／Ｐ２）が上記のごとき範囲にあることによって、より低温で硬化できる。また、後述する溶媒に対してより良好な溶解性を有することができる。また、硬化処理を経た硬化物がより良好な密着性、均一性、柔軟性を有することができる。 The ratio of the height of the absorption peak P1 due to the benzene ring to the height of the absorption peak P2 due to the imide group: P1/P2
In the infrared spectroscopic spectrum of the polyimide precursor in this embodiment, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P2 at a wave number of 1375 cm -1 due to the imide group (P1/P2 ) is preferably 2 or more, and may be 3 or more. Also, the ratio (P1/P2) is preferably 10 or less, more preferably 9 or less, and more preferably 5 or less.
The polyimide precursor can be cured at a lower temperature because the height ratio (P1/P2) is within the above range. Moreover, it can have better solubility in the solvent described later. In addition, the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
・アミド基による吸収ピークＰ３の高さに対する、ベンゼン環による吸収ピークＰ１の高さの比：Ｐ１／Ｐ３
　本実施形態におけるポリイミド前駆体の赤外分光スペクトルにおいて、アミド基による波数１６００ｃｍ－１の吸収ピークＰ３の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ３）は、２以上であることが好ましく、３以上であることがより好ましい。また、斯かる比（Ｐ１／Ｐ３）は、２０以下であることが好ましく、１２以下であることがより好ましく、１０以下であることがさらに好ましい。
　上記ポリイミド前駆体は、上記の高さの比（Ｐ１／Ｐ３）が上記のごとき範囲にあることによって、後述する溶媒に対してより良好な溶解性を有することができる。また、硬化処理を経た硬化物がより良好な密着性、均一性、柔軟性を有することができる。 The ratio of the height of the absorption peak P1 due to the benzene ring to the height of the absorption peak P3 due to the amide group: P1/P3
In the infrared spectroscopic spectrum of the polyimide precursor in this embodiment, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P3 at a wave number of 1600 cm -1 due to the amide group (P1/P3 ) is preferably 2 or more, more preferably 3 or more. Also, the ratio (P1/P3) is preferably 20 or less, more preferably 12 or less, even more preferably 10 or less.
When the height ratio (P1/P3) is within the above range, the polyimide precursor can have better solubility in the solvent described below. In addition, the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
・カルボキシ基による吸収ピークＰ４の高さに対する、ベンゼン環による吸収ピークＰ１の高さの比：Ｐ１／Ｐ４
　本実施形態におけるポリイミド前駆体の赤外分光スペクトルにおいて、カルボキシ基による波数１４１３ｃｍ－１の吸収ピークＰ４の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ４）は、２以上であることが好ましく、３以上であることがより好ましい。また、斯かる比（Ｐ１／Ｐ４）は、２０以下であることが好ましく、１２以下であることがより好ましく、１１以下であることがさらに好ましい。
　上記ポリイミド前駆体は、上記の高さの比（Ｐ１／Ｐ４）が上記のごとき範囲にあることによって、後述する溶媒に対してより良好な溶解性を有することができる。また、硬化処理を経た硬化物がより良好な密着性、均一性、柔軟性を有することができる。 -Ratio of the height of the absorption peak P1 due to the benzene ring to the height of the absorption peak P4 due to the carboxy group: P1/P4
In the infrared spectroscopy spectrum of the polyimide precursor in this embodiment, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P4 at a wave number of 1413 cm -1 due to the carboxy group (P1/P4 ) is preferably 2 or more, more preferably 3 or more. Also, the ratio (P1/P4) is preferably 20 or less, more preferably 12 or less, and even more preferably 11 or less.
When the height ratio (P1/P4) is within the above range, the polyimide precursor can have better solubility in the solvent described below. In addition, the cured product that has undergone the curing treatment can have better adhesion, uniformity and flexibility.
　上記のポリイミド前駆体におけるベンゼン環は、無置換のベンゼン環であってもよく、ベンゼン環を構成する複数の炭素原子にそれぞれ結合した水素が置換基に置き換わった、置換されたベンゼン環であってもよい。置換されたベンゼン環の置換基は、例えば、炭素数１以上３以下のアルキル基、炭素数１以上３以下のアルコキシ基、炭素数１以上３以下のアルコキシシリル基、又は、トリフルオロメチル基であってもよい。
　好ましくは、上記のポリイミド前駆体におけるベンゼン環は、無置換のベンゼン環、炭素数１以上３以下アルコキシシリル基で置換されたベンゼン環、又は、トリフルオロメチル基で置換されたベンゼン環である。
　より好ましくは、上記のポリイミド前駆体におけるベンゼン環は、無置換のベンゼン環である。換言すると、ポリイミド前駆体のベンゼン環を構成する炭素原子には、１価の置換基（ハロゲン原子など）が結合していないことが好ましい。さらに換言すると、ベンゼン環を構成する炭素原子に結合している１価の基は、水素原子（－Ｈ）であることが好ましい。 The benzene ring in the above polyimide precursor may be an unsubstituted benzene ring, or a substituted benzene ring in which hydrogen atoms respectively bonded to a plurality of carbon atoms constituting the benzene ring are substituted with substituents. good too. The substituent of the substituted benzene ring is, for example, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an alkoxysilyl group having 1 to 3 carbon atoms, or a trifluoromethyl group. There may be.
Preferably, the benzene ring in the polyimide precursor is an unsubstituted benzene ring, a benzene ring substituted with an alkoxysilyl group having 1 to 3 carbon atoms, or a benzene ring substituted with a trifluoromethyl group.
More preferably, the benzene ring in the polyimide precursor is an unsubstituted benzene ring. In other words, it is preferable that a monovalent substituent (such as a halogen atom) is not bonded to the carbon atoms constituting the benzene ring of the polyimide precursor. In other words, the monovalent group bonded to the carbon atoms constituting the benzene ring is preferably a hydrogen atom (--H).
　ポリイミド前駆体としては、例えば後述する式（３）で示されるポリイミド前駆体などを採用できる。具体的には、ポリイミド前駆体としては、製品名「カプトンＨ」（東レ・デュポン社製）を部分的に加水分解させた部分加水分解物を採用できる。
　例えば、廃棄されたポリイミド樹脂フィルムに対して加水分解処理を施すことによって、本実施形態におけるポリイミド前駆体を得ることができる。 As the polyimide precursor, for example, a polyimide precursor represented by formula (3) described later can be used. Specifically, as the polyimide precursor, a partial hydrolyzate obtained by partially hydrolyzing the product name "Kapton H" (manufactured by DuPont-Toray Co., Ltd.) can be used.
For example, the polyimide precursor in the present embodiment can be obtained by subjecting a discarded polyimide resin film to hydrolysis treatment.
　本実施形態の硬化用組成物に含まれるオキサゾリン化合物は、分子中に１つ又は複数のオキサゾリン環を含む化合物である。オキサゾリン化合物としては、低分子化合物又は高分子化合物が挙げられる。 The oxazoline compound contained in the curable composition of this embodiment is a compound containing one or more oxazoline rings in the molecule. Oxazoline compounds include low-molecular-weight compounds and high-molecular-weight compounds.
　オキサゾリン化合物は、分子量が１０００未満の低分子オキサゾリン化合物であってもよく、分子量が１０００以上の高分子オキサゾリン化合物であってもよい。 The oxazoline compound may be a low-molecular-weight oxazoline compound with a molecular weight of less than 1,000, or a high-molecular-weight oxazoline compound with a molecular weight of 1,000 or more.
　低分子オキサゾリン化合物としては、例えば、２つのオキサゾリン環同士が直接結合している化合物、２つのオキサゾリン環が有機基を介して結合している化合物、又は、３つのオキサゾリン環を有する化合物などが挙げられる。 Examples of low-molecular-weight oxazoline compounds include compounds in which two oxazoline rings are directly bonded to each other, compounds in which two oxazoline rings are bonded via an organic group, or compounds having three oxazoline rings. be done.
　２つのオキサゾリン環同士が直接結合している化合物としては、例えば２，２’－ビス（２－オキサゾリン）、２，２’－ビス－４－ベンジル－２－オキサゾリンなどが挙げられる。
　２つのオキサゾリン環が有機基を介して結合している化合物としては、１，４－ビス（４，５－ジヒドロ－２－オキサゾリル）ベンゼン、１，３－ビス（４，５－ジヒドロ－２－オキサゾリル）ベンゼン、２，６－ビス（イソプロピル－２－オキサゾリン－２－イル）ピリジン、２，２’－メチレンビス（４－ｔｅｒｔ－ブチル－２－オキサゾリン）、２，２’－メチレンビス（４－フェニル－２－オキサゾリン）などが挙げられる。
　３つのオキサゾリン環を有する化合物としては、１，２，４－トリス－（２－オキサゾリン－２－イル）ベンゼンなどが挙げられる。 Examples of compounds in which two oxazoline rings are directly bonded to each other include 2,2'-bis(2-oxazoline) and 2,2'-bis-4-benzyl-2-oxazoline.
Compounds in which two oxazoline rings are bonded via an organic group include 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, 1,3-bis(4,5-dihydro-2- oxazolyl)benzene, 2,6-bis(isopropyl-2-oxazolin-2-yl)pyridine, 2,2'-methylenebis(4-tert-butyl-2-oxazoline), 2,2'-methylenebis(4-phenyl -2-oxazoline) and the like.
Compounds having three oxazoline rings include 1,2,4-tris-(2-oxazoline-2-yl)benzene and the like.
　高分子オキサゾリン化合物としては、例えば、側鎖の末端にオキサゾリン環を有し且つ少なくともアクリル酸エステルが重合したオキサゾリン環含有アクリル系ポリマーなどが挙げられる。オキサゾリン環含有アクリル系ポリマーは、オキサゾリン環を有するアクリル酸エステルモノマーが少なくともモノマーの１種として重合した高分子化合物である。斯かるオキサゾリン環含有アクリル系ポリマーは、ホモポリマーであってもよく、コポリマーであってもよい。
　オキサゾリン環含有アクリル系ポリマーとしては、例えば、製品名「エポクロスＷＳ」シリーズ（日本触媒社製）、「エポクロスＫ－２０００」シリーズ（日本触媒社製）などを採用できる。 The polymer oxazoline compound includes, for example, an oxazoline ring-containing acrylic polymer having an oxazoline ring at the end of a side chain and polymerized with at least an acrylic acid ester. The oxazoline ring-containing acrylic polymer is a polymer compound obtained by polymerizing an acrylic acid ester monomer having an oxazoline ring as at least one of the monomers. Such oxazoline ring-containing acrylic polymers may be homopolymers or copolymers.
As the oxazoline ring-containing acrylic polymer, for example, the product name "Epocross WS" series (manufactured by Nippon Shokubai Co., Ltd.), "Epocross K-2000" series (manufactured by Nippon Shokubai Co., Ltd.), and the like can be used.
　オキサゾリン化合物において、オキサゾリン環を構成する炭素原子に結合している１価の基は、下記式（２）に示すように水素原子（－Ｈ）のみであることが好ましい。
Figure JPOXMLDOC01-appb-C000003
 In the oxazoline compound, the monovalent group bonded to the carbon atoms constituting the oxazoline ring is preferably only a hydrogen atom (--H) as shown in formula (2) below.
Figure JPOXMLDOC01-appb-C000003
　オキサゾリン化合物としては、ポリイミド前駆体との反応性がより良好である点、硬化処理後の硬化物がより良好な保存安定性を有し得る点で、高分子オキサゾリン化合物が好ましく、上述した側鎖の末端にオキサゾリン環を有するオキサゾリン環含有アクリル系ポリマーがより好ましい。 As the oxazoline compound, a high molecular weight oxazoline compound is preferable in terms of better reactivity with the polyimide precursor and better storage stability of the cured product after the curing treatment. An oxazoline ring-containing acrylic polymer having an oxazoline ring at the end of is more preferable.
　オキサゾリン化合物のオキサゾリン基量（オキサゾリン環量）は、１［ｍｍｏｌ／ｇ］以上１０［ｍｍｏｌ／ｇ］以下であることが好ましく、３［ｍｍｏｌ／ｇ］以上であることがより好ましい。
　高分子オキサゾリン化合物のオキサゾリン基量は、高分子オキサゾリン化合物を構成するオキサゾリン基を有するモノマー単位と、その他のモノマー単位との量比を基にして算出できる。斯かる量比は、例えば、核磁気共鳴分析計（ＮＭＲ）による１Ｈ－ＮＭＲ分析結果における、オキサゾリン基に由来するピーク強度と、その他のモノマーに由来するピーク強度とを基にして求めることができる。 The oxazoline group content (oxazoline ring content) of the oxazoline compound is preferably 1 [mmol/g] or more and 10 [mmol/g] or less, more preferably 3 [mmol/g] or more.
The amount of oxazoline groups in the high-molecular-weight oxazoline compound can be calculated based on the quantitative ratio between the monomer unit having an oxazoline group and other monomer units constituting the high-molecular-weight oxazoline compound. Such a ratio can be determined, for example, based on the peak intensity derived from the oxazoline group and the peak intensity derived from other monomers in the 1 H-NMR analysis results by a nuclear magnetic resonance spectrometer (NMR). can.
　なお、オキサゾリン化合物として、１種が単独で採用されてもよく、２種以上が組み合わされて採用されてもよい。 As the oxazoline compound, one type may be employed alone, or two or more types may be employed in combination.
　本実施形態の硬化用組成物において、上述したように、前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下である。
　上記のオキサゾリン環の量は、０．３０ｍｏｌ以上であってもよく、０．３５ｍｏｌ以上であってもよく、０．３９ｍｏｌ以上であってもよい。また、上記のオキサゾリン環の量は、１．５０ｍｏｌ以下であってもよく、１．２０ｍｏｌ以下であってもよい。 In the curable composition of the present embodiment, as described above, the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
The amount of the oxazoline ring may be 0.30 mol or more, 0.35 mol or more, or 0.39 mol or more. Moreover, the amount of the oxazoline ring may be 1.50 mol or less, or may be 1.20 mol or less.
　本実施形態の硬化用組成物において、ポリイミド前駆体は、ポリイミド樹脂の部分加水分解物であることが好ましく、且つ、オキサゾリン化合物は、高分子オキサゾリン化合物（例えば、側鎖の末端にオキサゾリン環を有するオキサゾリン環含有アクリル系ポリマー）であることが好ましい。
　部分加水分解物のポリイミド前駆体は、モノマーから構成したポリイミド前駆体よりも低分子化合物の量が多いため、硬化されたときに硬くてもろくなる場合がある。これに対して、本実施形態の硬化用組成物が高分子オキサゾリン化合物をさらに含むことによって、上記の硬くてもろいという物性を抑制できる。従って、硬化した硬化物の被着体に対する密着性をより良好にできる。 In the curable composition of the present embodiment, the polyimide precursor is preferably a partial hydrolyzate of a polyimide resin, and the oxazoline compound is a polymeric oxazoline compound (for example, a oxazoline ring-containing acrylic polymer).
Partially hydrolyzed polyimide precursors have a higher amount of low-molecular-weight compounds than polyimide precursors composed of monomers, and therefore may be hard and brittle when cured. In contrast, when the curable composition of the present embodiment further contains a high-molecular-weight oxazoline compound, the physical properties of being hard and brittle can be suppressed. Therefore, the adhesion of the cured product to the adherend can be improved.
　本実施形態の硬化用組成物は、ポリイミド前駆体１００質量部に対してオキサゾリン化合物を５質量部以上９５質量部以下含むことが好ましい。
　本実施形態の硬化用組成物は、ポリイミド前駆体１００質量部に対してオキサゾリン化合物を８質量部以上含んでもよく、１０質量部以上含んでもよい。
　本実施形態の硬化用組成物は、ポリイミド前駆体１００質量部に対してオキサゾリン化合物を９０質量部以下含んでもよく、８０質量部以下含んでもよく、７０質量部以下含んでもよい。 The curable composition of the present embodiment preferably contains 5 parts by mass or more and 95 parts by mass or less of the oxazoline compound with respect to 100 parts by mass of the polyimide precursor.
The curable composition of the present embodiment may contain 8 parts by mass or more, or 10 parts by mass or more of the oxazoline compound based on 100 parts by mass of the polyimide precursor.
The curable composition of the present embodiment may contain 90 parts by mass or less, 80 parts by mass or less, or 70 parts by mass or less of the oxazoline compound with respect to 100 parts by mass of the polyimide precursor.
　本実施形態の硬化用組成物は、溶媒を含んでもよい。溶媒としては、非極性溶媒、又は、極性溶媒が挙げられる。非極性溶媒としては炭素原子及び水素原子のみを分子中に含む炭化水素系溶媒、四塩化炭素などの塩素系溶媒等が挙げられる。本実施形態の硬化用組成物は、上記ポリイミド前駆体及び上記オキサゾリン化合物の両方を溶解させるための極性溶媒を含むことが好ましい。極性溶媒は、炭素原子及び水素原子以外の原子（例えば酸素原子、窒素原子）も分子中に含む化合物である。本実施形態の硬化用組成物において、ポリイミド前駆体及びオキサゾリン化合物は、いずれも極性溶媒に溶解している。 The curable composition of this embodiment may contain a solvent. Solvents include non-polar solvents and polar solvents. Examples of non-polar solvents include hydrocarbon solvents containing only carbon atoms and hydrogen atoms in the molecule, chlorine solvents such as carbon tetrachloride, and the like. The curable composition of the present embodiment preferably contains a polar solvent for dissolving both the polyimide precursor and the oxazoline compound. A polar solvent is a compound that also contains atoms other than carbon atoms and hydrogen atoms (eg, oxygen atoms, nitrogen atoms) in the molecule. In the curable composition of this embodiment, both the polyimide precursor and the oxazoline compound are dissolved in a polar solvent.
　極性溶媒としては、アミン系溶媒、アミド系溶媒、ケトン系溶媒、エーテル系溶媒、ピロリドン系溶媒、グリコールエーテル系溶媒、エステル系溶媒、アルコール系溶媒、多価アルコール系溶媒、ハロゲン系溶媒、水などが挙げられる。 Polar solvents include amine solvents, amide solvents, ketone solvents, ether solvents, pyrrolidone solvents, glycol ether solvents, ester solvents, alcohol solvents, polyhydric alcohol solvents, halogen solvents, water, etc. is mentioned.
　アミン系溶媒としては、例えば、アンモニア（水）、ジエチルアミン、エチルエタノールアミン、ジエタノールアミン、トリエタノールアミン、モノエタノールアミン、モノプロパノールアミン、イソプロパノールアミン、トリエチルアミン、トルブチルアミン、ジメチルアミノエタノール、ジエチルアミノエタノール、メチルエタノールアミン、メチルジエタノールアミン、エチルアミノエタノール、ジエタノールアミン等が挙げられる。
　アミド系溶媒としては、例えば、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド等が挙げられる。
　ケトン系溶媒としては、例えば、メチルエチルケトン、メチルイソブチルケトン、γ－ブチロラクトン、シクロヘキサノン、シクロペンタノン等が挙げられる。
　エーテル系溶媒としては、例えば、テトラヒドロフラン、１，３－ジオキソラン、１，４－ジオキサン、メチルフェニルエーテル等が挙げられる。
　ピロリドン系溶媒としては、例えば、Ｎ－メチル－２－ピロリドン等が挙げられる。
　グリコールエーテル系溶媒としては、例えば、メチルジグライム、エチルジグライム、メチルトリグライム、エチレングリコールモノブチルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、１－メトキシ－２－プロパノール、エチレングリコールモノエチルエーテル等、又はそれらのアセテート等が挙げられる。
　エステル系溶媒としては、例えば、酢酸エチル、酢酸ブチル、酢酸イソプロピル等が挙げられる。
　アルコール系溶媒としては、例えば、メチルアルコール、エチルアルコール、１－プロパノール、２－プロパノール、１－ブタノール、２－ブタノール、２－メチル－1－プロパノール、２－メチル－２－プロパノール等が挙げられる。
　多価アルコール系溶媒としては、例えば、グリセリン等が挙げられる。
　ハロゲン系溶媒としては、例えば、クロロホルム、ジクロロメタン等が挙げられる。 Examples of amine-based solvents include ammonia (water), diethylamine, ethylethanolamine, diethanolamine, triethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, triethylamine, tributylamine, dimethylaminoethanol, diethylaminoethanol, and methylethanol. amine, methyldiethanolamine, ethylaminoethanol, diethanolamine and the like.
Examples of amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide.
Ketone solvents include, for example, methyl ethyl ketone, methyl isobutyl ketone, γ-butyrolactone, cyclohexanone, cyclopentanone and the like.
Examples of ether solvents include tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, methylphenyl ether and the like.
Examples of pyrrolidone-based solvents include N-methyl-2-pyrrolidone and the like.
Glycol ether solvents include, for example, methyldiglyme, ethyldiglyme, methyltriglyme, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, 1-methoxy-2-propanol, ethylene glycol monoethyl ether, etc. Or those acetates etc. are mentioned.
Examples of ester solvents include ethyl acetate, butyl acetate, isopropyl acetate and the like.
Examples of alcohol solvents include methyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol and the like.
Examples of polyhydric alcohol solvents include glycerin.
Examples of halogen-based solvents include chloroform and dichloromethane.
　極性溶媒としては、水性溶媒が好ましい。水性溶媒は、水、又は、水に対していかなる量比でも水に溶解する親水性有機溶媒である。本実施形態の硬化用組成物は、極性溶媒のうちの水性溶媒を含むことがより好ましく、少なくとも水を水性溶媒として含むことがより好ましい。 Aqueous solvents are preferred as polar solvents. Aqueous solvents are water or hydrophilic organic solvents that are soluble in water in any ratio relative to water. The curable composition of the present embodiment more preferably contains an aqueous solvent among polar solvents, and more preferably contains at least water as an aqueous solvent.
　親水性有機溶媒としては、例えば、ジメチルアミノエタノール、ジエタノールアミンといったアミン系溶媒、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミドといったアミド系溶媒、Ｎ－メチル－２－ピロリドンなどのピロリドン系溶媒、メチルアルコール、エチルアルコール、１－プロパノール、２－プロパノール、１－ブタノール、２－ブタノール、２－メチル－1－プロパノール、２－メチル－２－プロパノールといったアルコール系溶媒、エチレングリコールモノブチルエーテル、ジエチレングリコールモノブチルエーテル、１－メトキシ－２－プロパノール、プロピレングリコールモノメチルエーテルといったアルコールエーテル系溶媒、グリセリンなどの多価アルコール系溶媒が挙げられる。 Examples of hydrophilic organic solvents include amine solvents such as dimethylaminoethanol and diethanolamine, amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone, Alcohol solvents such as methyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether , 1-methoxy-2-propanol and propylene glycol monomethyl ether, and polyhydric alcohol solvents such as glycerin.
　アミン系溶媒は、ポリイミド前駆体、及び、斯かるポリイミド前駆体の硬化物に対して高い親和性を有する。そのため、硬化性組成物におけるポリイミド前駆体の溶解性を向上させる目的、又は、均一に近い硬化物を形成させる目的で、硬化性組成物にアミン系溶媒が配合されていることが好ましい。
　特に、アミン系溶媒としてのジメチルアミノエタノール、ジエタノールアミンは、沸点が比較的高いため、上記の硬化性組成物に対して加熱による硬化処理を施すときに、徐々に揮発する。これにより、硬化が進行した硬化物がより均一に近い硬化膜を形成できる。 Amine-based solvents have a high affinity for polyimide precursors and cured products of such polyimide precursors. Therefore, for the purpose of improving the solubility of the polyimide precursor in the curable composition, or for the purpose of forming a nearly uniform cured product, it is preferable that the curable composition contains an amine solvent.
In particular, dimethylaminoethanol and diethanolamine as amine-based solvents have relatively high boiling points, so they gradually volatilize when the curable composition is subjected to curing treatment by heating. As a result, the cured product in which curing has progressed can form a more uniform cured film.
　上記の極性溶媒は、複数種が組み合わされて用いられてもよい。また、上記の水性溶媒も、複数種が組み合わされて用いられてもよい。 A plurality of types of the above polar solvents may be used in combination. In addition, the above aqueous solvents may also be used in combination of multiple types.
　本実施形態の硬化用組成物は、極性溶媒（特に水性溶媒）を６０質量％以上含んでもよい。また、極性溶媒（特に水性溶媒）を、９９質量％以下含んでもよい。
　本実施形態の硬化用組成物中では、ポリイミド前駆体及びオキサゾリン化合物の総量が占める質量割合は、１質量％以上であってもよい。また、斯かる割合は、４０質量％以下であってもよい。 The curable composition of the present embodiment may contain 60% by mass or more of a polar solvent (particularly an aqueous solvent). Moreover, a polar solvent (especially an aqueous solvent) may be included in an amount of 99% by mass or less.
In the curable composition of the present embodiment, the total weight ratio of the polyimide precursor and the oxazoline compound may be 1% by weight or more. Moreover, such a ratio may be 40% by mass or less.
　上記の硬化用組成物は、上述した成分の他に、イミド化反応触媒、界面活性剤、酸化防止剤、レベリング剤、帯電防止剤、染料若しくは顔料、粘度調整剤、消泡剤、安定剤、ポリイミド樹脂以外の他の樹脂、又は、カップリング剤などをさらに含んでもよい。
　上記他の樹脂としては、例えば、アクリル樹脂、フッ素樹脂、エポキシ樹脂、フェノール樹脂、シリコーン樹脂、オレフィン樹脂、ポリエステル樹脂、ポリアミド樹脂、炭化水素樹脂等が挙げられる。
　これら成分は、硬化用組成物の塗布時の良好な作業性の向上、又は、硬化処理を経た硬化物の各種性能の向上を目的として配合され得る。 In addition to the components described above, the above curing composition includes an imidization reaction catalyst, a surfactant, an antioxidant, a leveling agent, an antistatic agent, a dye or pigment, a viscosity modifier, an antifoaming agent, a stabilizer, A resin other than the polyimide resin or a coupling agent may be further included.
Examples of the other resins include acrylic resins, fluorine resins, epoxy resins, phenol resins, silicone resins, olefin resins, polyester resins, polyamide resins, and hydrocarbon resins.
These components can be blended for the purpose of improving good workability during application of the curable composition, or improving various properties of the cured product that has undergone curing treatment.
　本実施形態の硬化用組成物の性状は、特に限定されないが、例えば液状である。なお、本実施形態の硬化用組成物は、固形状であってもよい。 The properties of the curable composition of the present embodiment are not particularly limited, but are liquid, for example. In addition, the curable composition of the present embodiment may be solid.
　本実施形態の硬化用組成物は、例えば、上記のポリイミド前駆体と、オキサゾリン化合物と、必要に応じて上述した極性溶媒とを混合することによって製造できる。 The curable composition of the present embodiment can be produced, for example, by mixing the above polyimide precursor, the oxazoline compound, and, if necessary, the above polar solvent.
　上述したように、ポリイミド前駆体は、ポリイミド樹脂を部分的に加水分解させることによって得ることができる。斯かる硬化用組成物の製造方法は、例えば、
　水およびアルカリ化合物の存在下でポリイミド樹脂を加水分解処理することによってポリイミド前駆体を調製する加水分解工程と、
　ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、オキサゾリン化合物のオキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下となるように、ポリイミド前駆体とオキサゾリン化合物とを混合して、硬化用組成物を調製する混合工程と、を備える。 As described above, a polyimide precursor can be obtained by partially hydrolyzing a polyimide resin. A method for producing such a curable composition includes, for example,
A hydrolysis step of preparing a polyimide precursor by hydrolyzing a polyimide resin in the presence of water and an alkaline compound;
A curable composition is prepared by mixing the polyimide precursor and the oxazoline compound so that the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor. and a mixing step.
　加水分解させる前のポリイミド樹脂は、例えば上記の一般式（１）で表されるポリイミド前駆体を生じさせるものであれば特に限定されない。ポリイミド樹脂の分子構造の具体例を図１の式（Ａ）～式（Ｊ）に示す。 The polyimide resin before hydrolysis is not particularly limited as long as it produces the polyimide precursor represented by the above general formula (1), for example. Specific examples of the molecular structure of the polyimide resin are shown in formulas (A) to (J) in FIG.
・加水分解工程
　加水分解工程において部分的に加水分解されるポリイミド樹脂としては、例えば廃棄されたポリイミド樹脂を用いることができる。具体的には、ポリイミド樹脂の成形品、より具体的にはポリイミド樹脂フィルムの廃棄物などを用いることができる。 - Hydrolysis step As the polyimide resin partially hydrolyzed in the hydrolysis step, for example, discarded polyimide resin can be used. Specifically, polyimide resin molded articles, more specifically polyimide resin film waste, and the like can be used.
　加水分解工程において、例えば５０℃以上１００℃以下の温度条件において、ポリイミド樹脂を加水分解処理することができる。
　加水分解工程において、加水分解処理の継続時間は、例えば１時間以上２４時間以下である。
　加水分解工程において、例えば、水酸化ナトリウム又は水酸化カリウムなどをアルカリ化合物として用いる。 In the hydrolysis step, the polyimide resin can be hydrolyzed under temperature conditions of, for example, 50° C. or higher and 100° C. or lower.
In the hydrolysis step, the duration of the hydrolysis treatment is, for example, 1 hour or more and 24 hours or less.
In the hydrolysis step, for example, sodium hydroxide or potassium hydroxide is used as an alkaline compound.
　加水分解工程において、例えば、ポリイミド前駆体の分子量が上述した所定範囲の分子量となるまで加水分解処理を継続してもよい。また、例えば、ポリイミド前駆体の赤外吸収分析による赤外分光スペクトルにおける上述した各吸収ピークの高さの比が、上述した所定範囲内となるまで加水分解処理を継続してもよい。 In the hydrolysis step, for example, the hydrolysis treatment may be continued until the molecular weight of the polyimide precursor reaches the above-mentioned predetermined range. Further, for example, the hydrolysis treatment may be continued until the ratio of the heights of the absorption peaks in the infrared spectroscopy spectrum obtained by infrared absorption analysis of the polyimide precursor falls within the above-described predetermined range.
　加水分解工程では、例えば、ポリイミド前駆体の質量平均分子量が、１，０００以上１００，０００以下となるまで加水分解処理を実施することができる。
　また、加水分解工程では、例えば、上述したＧＰＣ測定によって求められたポリイミド前駆体のＭｗ／Ｍｎが、１以上４以下となるまで加水分解処理を実施することができる。 In the hydrolysis step, for example, the hydrolysis treatment can be performed until the weight average molecular weight of the polyimide precursor reaches 1,000 or more and 100,000 or less.
Further, in the hydrolysis step, for example, the hydrolysis treatment can be performed until the Mw/Mn of the polyimide precursor obtained by the GPC measurement described above becomes 1 or more and 4 or less.
　例えば、加水分解工程では、ポリイミド前駆体の赤外分光スペクトルにおいて、イミド基による波数１３７５ｃｍ－１の吸収ピークＰ２の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ２）が、２以上１０以下となるまで加水分解処理を実施することができる。
　また、加水分解工程では、ポリイミド前駆体の赤外分光スペクトルにおいて、アミド基による波数１６００ｃｍ－１の吸収ピークＰ３の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ３）が、２以上２０以下となるまで加水分解処理を実施することができる。
　また、加水分解工程では、ポリイミド前駆体の赤外分光スペクトルにおいて、カルボキシ基による波数１４１３ｃｍ－１の吸収ピークＰ４の高さに対する、ベンゼン環による波数１５００ｃｍ－１における吸収ピークＰ１の高さの比（Ｐ１／Ｐ４）が、２以上２０以下となるまで加水分解処理を実施することができる。 For example, in the hydrolysis step, in the infrared spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm due to the benzene ring to the height of the absorption peak P2 due to the imide group at a wave number of 1375 cm -1 ( The hydrolysis treatment can be carried out until P1/P2) becomes 2 or more and 10 or less.
In the hydrolysis step, in the infrared spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P3 at a wave number of 1600 cm -1 due to the amide group ( The hydrolysis treatment can be carried out until P1/P3) becomes 2 or more and 20 or less.
Further, in the hydrolysis step, in the infrared spectroscopic spectrum of the polyimide precursor, the ratio of the height of the absorption peak P1 at a wave number of 1500 cm -1 due to the benzene ring to the height of the absorption peak P4 at a wave number of 1413 cm -1 due to the carboxy group ( The hydrolysis treatment can be carried out until P1/P4) becomes 2 or more and 20 or less.
　なお、加水分解工程の後、ポリイミド前駆体を溶解させた状態で次の混合工程を実施してもよい。一方、加水分解工程の後、ポリイミド前駆体を粉末化するために、加水分解処理時に用いた溶媒を、乾燥処理等によって揮発させてもよい。 After the hydrolysis step, the next mixing step may be performed with the polyimide precursor dissolved. On the other hand, in order to pulverize the polyimide precursor after the hydrolysis step, the solvent used in the hydrolysis treatment may be volatilized by drying treatment or the like.
　上記のごとき加水分解処理によって得られたポリイミド前駆体は、例えば、下記式（３）で表される。式（３）で表されるポリイミド前駆体は、構造単位ａ及び構造単位ｂを分子中に有する。構造単位ａは、イミド基が加水分解された部分（環状イミド構造がアミック酸構造となった部分）を有する。構造単位ｂは、イミド基が加水分解されず残存した部分を有する。式（３）において、構造単位ａ（左側部分）及び構造単位ｂ（右側部分）は、上述した繰り返し構造単位にそれぞれ相当する。
　なお、ポリイミド前駆体は、分子鎖の末端にカルボキシ基を２つ有し得る。加水分解処理によって環状イミド構造が完全に加水分解されることによって、これらのカルボキシ基が生じ得る。
Figure JPOXMLDOC01-appb-C000004
 The polyimide precursor obtained by the hydrolysis treatment as described above is represented, for example, by the following formula (3). The polyimide precursor represented by formula (3) has a structural unit a and a structural unit b in its molecule. Structural unit a has a portion where the imide group is hydrolyzed (a portion where the cyclic imide structure becomes an amic acid structure). Structural unit b has a portion in which the imide group is not hydrolyzed and remains. In formula (3), structural unit a (left portion) and structural unit b (right portion) correspond to the repeating structural units described above.
In addition, the polyimide precursor may have two carboxy groups at the terminal of the molecular chain. These carboxy groups can be generated by complete hydrolysis of the cyclic imide structure by hydrolysis treatment.
Figure JPOXMLDOC01-appb-C000004
　加水分解工程において、温度を高めること、又は、反応液のｐＨを高める（反応液をよりアルカリ性にする）ことによって、ポリイミド前駆体の質量平均分子量を小さくすることができ、ポリイミド前駆体におけるアミック酸構造の割合を高めることができる。
　また、加水分解工程において、加水分解反応時間を長くすることによって、上述したＭｗ／Ｍｎを小さくすることができる。 In the hydrolysis step, by increasing the temperature or increasing the pH of the reaction solution (making the reaction solution more alkaline), the weight average molecular weight of the polyimide precursor can be reduced, and the amic acid in the polyimide precursor The proportion of structure can be increased.
In addition, the aforementioned Mw/Mn can be reduced by lengthening the hydrolysis reaction time in the hydrolysis step.
・混合工程
　混合工程において、例えば、上記のごとく調製した粉末状ポリイミド前駆体と、オキサゾリン化合物と、溶媒とを混合する。
　混合するための装置としては、一般的なものを使用できる。必要に応じて、加温しつつ混合撹拌してもよい。 Mixing step In the mixing step, for example, the powdery polyimide precursor prepared as described above, the oxazoline compound, and the solvent are mixed.
A common device can be used for mixing. If necessary, they may be mixed and stirred while being heated.
　混合工程において、ポリイミド前駆体１００質量部に対してオキサゾリン化合物が、上記のごとく特定の量比となるように、ポリイミド前駆体とオキサゾリン化合物とを混合する。 In the mixing step, the polyimide precursor and the oxazoline compound are mixed so that the oxazoline compound has a specific amount ratio as described above with respect to 100 parts by mass of the polyimide precursor.
　混合工程では、例えば、少なくとも水を含む溶媒と、上記のポリイミド前駆体と、オキサゾリン化合物とを含む溶液を調製する。また、例えば、上記の粉末状ポリイミド前駆体と、オキサゾリン化合物が溶解した水溶液とを混合することによって、硬化用組成物を製造してもよい。
　混合工程によってポリイミド前駆体及びオキサゾリン化合物を溶媒に溶解させて溶液状の硬化用組成物を調製することが好ましく、水溶液の状態の硬化用組成物を調製することがより好ましい。硬化用組成物が溶液状態（特に水溶液の状態）であることによって、硬化用組成物を様々な方法で塗布することができる。そのため、硬化用組成物の使用用途範囲が広くなるという利点がある。また、硬化用組成物が水溶液であることにより、可燃性を有しないことから、安全性が高くなるという利点がある。 In the mixing step, for example, a solution containing at least a water-containing solvent, the above polyimide precursor, and an oxazoline compound is prepared. Alternatively, for example, the curable composition may be produced by mixing the powdery polyimide precursor and an aqueous solution in which the oxazoline compound is dissolved.
It is preferable to dissolve the polyimide precursor and the oxazoline compound in the solvent in the mixing step to prepare a curable composition in the form of a solution, and more preferably to prepare the curable composition in the form of an aqueous solution. Due to the fact that the curable composition is in the form of a solution (particularly in the form of an aqueous solution), the curable composition can be applied in various ways. Therefore, there is an advantage that the application range of the curable composition is widened. In addition, since the curable composition is an aqueous solution, it is not flammable, so there is an advantage that safety is enhanced.
　上記の硬化用組成物は、例えば、電線、フィルム、フレキシブル回路基板、半導体などの被着体に塗布されて使用される。塗布された上記の硬化用組成物は、加熱等の硬化処理を施されることによって硬化物（具体的には硬化樹脂など）となる。
　上記の硬化用組成物は、例えば、繊維塗布用の硬化用組成物、樹脂フィルム塗布用の硬化用組成物、樹脂成形品塗布用の硬化用組成物、又は、金属塗布用の硬化用組成物のいずれかであってもよい。
　硬化物（例えば、硬化樹脂成形品）となる上記の硬化用組成物は、例えば、フィルムの用途、塗料の用途、電気絶縁材料の用途、耐熱部品の用途、耐熱容器の用途、繊維の用途などで使用されてもよい。 The curable composition described above is used by being applied to an adherend such as an electric wire, film, flexible circuit board, or semiconductor. The applied curable composition is subjected to a curing treatment such as heating to form a cured product (specifically, a cured resin or the like).
The above-mentioned curing composition is, for example, a curing composition for fiber coating, a curing composition for resin film coating, a curing composition for resin molding coating, or a curing composition for metal coating may be either
The above-mentioned curable composition that becomes a cured product (e.g., cured resin molded article) is used, for example, as a film, as a paint, as an electrical insulating material, as a heat-resistant component, as a heat-resistant container, as a fiber, etc. may be used in
　上記の硬化用組成物の使用方法（換言すると、上記の硬化用組成物を硬化させた硬化物の製造方法）は、特に限定されない。斯かる使用方法では、例えば、上記の硬化用組成物を被塗布物（基材などの被着体等）の上に塗布、又は、被塗布物に含浸させた後に硬化させることによって、硬化物（硬化塗膜など）を形成することができる。
　硬化用組成物の塗布方法としては、例えば、スプレー塗装法、ディップコーティング法、スピンコーティング法、ダイコーティング法、グラビアコーティング法等の一般的な塗布方法を採用できる。
　基材に塗布された硬化用組成物及び基材に加熱処理を施すことによって、硬化用組成物に含まれている溶媒を揮発させることができる。加熱処理としては、特に制限されず、熱風加熱処理、赤外線加熱処理等の一般的な方法を採用できる。加熱処理における加熱条件は、例えば６０℃～１００℃で３０分間などである。
　その後、より高い温度で加熱処理を実施して熱硬化をさらに進行させることができる。斯かるより高温での加熱処理も特に限定されず、一般的な方法で実施できる。高温での加熱処理の温度条件は、２００℃以上であってもよく、好ましくは３００℃～４００℃である。加熱時間は１０分間～５時間であってもよく、好ましくは１０～６０分である。この高温での加熱処理の間に、溶媒の揮発がさらに進行し、ポリイミド樹脂前駆体におけるイミド化がさらに進行し、硬化が進行した硬化膜が形成される。なお、加熱処理は、不活性ガス雰囲気下、又は、減圧条件下で実施することもできる。 The method of using the curable composition (in other words, the method of producing a cured product obtained by curing the curable composition) is not particularly limited. In such a method of use, for example, the above-described curing composition is applied onto an object to be coated (an adherend such as a substrate), or impregnated into the object and then cured to obtain a cured product. (such as a cured coating film) can be formed.
As a method for applying the curable composition, for example, general application methods such as spray coating, dip coating, spin coating, die coating, and gravure coating can be used.
The solvent contained in the curable composition can be volatilized by subjecting the curable composition applied to the substrate and the substrate to heat treatment. The heat treatment is not particularly limited, and general methods such as hot air heat treatment and infrared heat treatment can be employed. The heating conditions for the heat treatment are, for example, 60° C. to 100° C. for 30 minutes.
A heat treatment can then be performed at a higher temperature to further promote thermosetting. Such a heat treatment at a higher temperature is not particularly limited, either, and can be carried out by a general method. The temperature condition for the heat treatment at high temperature may be 200°C or higher, preferably 300°C to 400°C. The heating time may be 10 minutes to 5 hours, preferably 10 to 60 minutes. During this high-temperature heat treatment, the evaporation of the solvent further progresses, imidization in the polyimide resin precursor further progresses, and a cured film in which curing has progressed is formed. Note that the heat treatment can be performed under an inert gas atmosphere or under reduced pressure conditions.
　本発明の硬化用組成物及び硬化物は、上記例示の通りであるが、本発明は、上記例示の実施形態に限定されるものではない。また、本発明では、一般の硬化用組成物などにおいて採用される種々の形態を、本発明の効果を損ねない範囲で採用することができる。 The curable composition and cured product of the present invention are as exemplified above, but the present invention is not limited to the above-exemplified embodiments. Moreover, in the present invention, various forms employed in general curable compositions and the like can be employed as long as the effects of the present invention are not impaired.
　本明細書によって開示される事項は、以下のものを含む。
（１）
　ポリイミド樹脂のイミド結合の一部が加水分解されたポリイミド前駆体と、
　オキサゾリン環を分子中に有するオキサゾリン化合物とを含み、
　前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下である、硬化用組成物。
（２）
　前記オキサゾリン化合物が、分子量１０００未満の低分子オキサゾリン化合物、又は、分子量１０００以上の高分子オキサゾリン化合物のいずれかである、上記（１）に記載の硬化用組成物。
（３）
　水性溶媒をさらに含む、上記（１）又は（２）に記載の硬化用組成物。
（４）
　前記水性溶媒が、水と、水に対して任意の量比で水に溶解する親水性有機溶媒とを含む、上記（３）に記載の硬化用組成物。
（５）
　前記親水性有機溶媒が、ジメチルアミノエタノール及びジエタノールアミンのうち少なくとも一方を含む、上記（４）に記載の硬化用組成物。
（６）
　前記ポリイミド前駆体の分子中では、ベンゼン環１つに対する窒素原子数がモル比で０．２以上１．０以下である、上記（１）乃至（５）のいずれかに記載の硬化用組成物。
（７）
　前記ポリイミド前駆体がベンゼン環を分子中に有し、
　前記ポリイミド前駆体を赤外分光分析した赤外分光スペクトルが、ベンゼン環による波数１５００ｃｍ－１の吸収ピークＰ１と、イミド基による波数１３７５ｃｍ－１の吸収ピークＰ２と、を示し、
　前記吸収ピークＰ２の高さに対する前記吸収ピークＰ１の高さの比（Ｐ１／Ｐ２）が、２以上１０以下である、上記（１）乃至（６）のいずれかに記載の硬化用組成物。
（８）
　前記ポリイミド前駆体がベンゼン環を分子中に有し、
　前記ポリイミド前駆体を赤外分光分析した赤外分光スペクトルが、ベンゼン環による波数１５００ｃｍ－１の吸収ピークＰ１と、アミド基による波数１６００ｃｍ－１の吸収ピークＰ３と、を示し、
　前記吸収ピークＰ３の高さに対する前記吸収ピークＰ１の高さの比（Ｐ１／Ｐ３）が、２以上２０以下である、上記（１）乃至（７）のいずれかに記載の硬化用組成物。
（９）
　前記ポリイミド前駆体がベンゼン環を分子中に有し、
　前記ポリイミド前駆体を赤外分光分析した赤外分光スペクトルが、ベンゼン環による波数１５００ｃｍ－１の吸収ピークＰ１と、カルボキシ基による波数１４１３ｃｍ－１の吸収ピークＰ４と、を示し、
　前記吸収ピークＰ４の高さに対する前記吸収ピークＰ１の高さの比（Ｐ１／Ｐ４）が、２以上２０以下である、上記（１）乃至（８）のいずれかに記載の硬化用組成物。
（１０）
　繊維塗布用の硬化用組成物、樹脂フィルム塗布用の硬化用組成物、樹脂成形品塗布用の硬化用組成物、又は、金属塗布用の硬化用組成物のいずれかである、上記（１）乃至（９）のいずれかに記載の硬化用組成物。
（１１）
　上記（１）乃至（１０）のいずれかに記載された硬化用組成物が硬化した硬化物。
（１２）
　フィルムの用途、塗料の用途、電気絶縁材料の用途、耐熱部品の用途、耐熱容器の用途、又は、繊維の用途で使用される、上記（１１）に記載の硬化物。
（１３）
　上記（１）乃至（１０）のいずれかに記載された硬化用組成物を、被塗布物上に塗布又は被塗布物に含浸させた後に硬化させることによって、硬化物を形成する、硬化用組成物の使用方法。 Matters disclosed by this specification include the following.
(1)
A polyimide precursor in which a part of the imide bond of the polyimide resin is hydrolyzed,
and an oxazoline compound having an oxazoline ring in the molecule,
A curable composition, wherein the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
(2)
The curable composition according to (1) above, wherein the oxazoline compound is either a low-molecular-weight oxazoline compound having a molecular weight of less than 1,000 or a high-molecular-weight oxazoline compound having a molecular weight of 1,000 or more.
(3)
The curable composition according to (1) or (2) above, further comprising an aqueous solvent.
(4)
The curable composition according to (3) above, wherein the aqueous solvent contains water and a hydrophilic organic solvent that dissolves in water in an arbitrary amount ratio with respect to water.
(5)
The curable composition according to (4) above, wherein the hydrophilic organic solvent contains at least one of dimethylaminoethanol and diethanolamine.
(6)
The curable composition according to any one of (1) to (5) above, wherein the number of nitrogen atoms per benzene ring in the molecule of the polyimide precursor is 0.2 or more and 1.0 or less in molar ratio. .
(7)
The polyimide precursor has a benzene ring in the molecule,
An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm −1 due to a benzene ring and an absorption peak P2 at a wave number of 1375 cm −1 due to an imide group,
The curable composition according to any one of (1) to (6) above, wherein the ratio (P1/P2) of the height of the absorption peak P1 to the height of the absorption peak P2 is 2 or more and 10 or less.
(8)
The polyimide precursor has a benzene ring in the molecule,
An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm −1 due to a benzene ring and an absorption peak P3 at a wave number of 1600 cm −1 due to an amide group,
The curable composition according to any one of (1) to (7) above, wherein the ratio (P1/P3) of the height of the absorption peak P1 to the height of the absorption peak P3 is 2 or more and 20 or less.
(9)
The polyimide precursor has a benzene ring in the molecule,
An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm −1 due to a benzene ring and an absorption peak P4 at a wave number of 1413 cm −1 due to a carboxy group,
The curable composition according to any one of (1) to (8) above, wherein the ratio (P1/P4) of the height of the absorption peak P1 to the height of the absorption peak P4 is 2 or more and 20 or less.
(10)
The above (1), which is any one of a curing composition for fiber coating, a curing composition for resin film coating, a curing composition for resin molding coating, or a curing composition for metal coating. The curable composition according to any one of (9).
(11)
A cured product obtained by curing the curable composition according to any one of (1) to (10) above.
(12)
The cured product according to (11) above, which is used for film applications, paint applications, electrical insulating material applications, heat-resistant parts applications, heat-resistant container applications, or fiber applications.
(13)
A curable composition for forming a cured product by applying the curable composition described in any one of the above (1) to (10) onto an object to be coated or impregnating the object and then curing the composition. how to use things.
　次に実施例を挙げて本発明をさらに詳しく説明するが、本発明はこれらに限定されるものではない。 Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these.
　硬化用組成物を製造するための各原料について以下に説明する。
＜主な原料＞
（Ａ－１）ポリイミド前駆体（粉体状）
　・加水分解前のポリイミド樹脂成形品：
　　ポリイミド樹脂　製品名「カプトンＨ」（東レ・デュポン製）
　　　　　　　　　　　　　　図１の式（Ａ）に示す分子構造のポリイミド樹脂
　・加水分解後の質量平均分子量（Ｍｗ）：１１，０００
　・加水分解後のＭｗ／Ｍｎ：１．６
　上記（Ａ－１）は、以下のようにして調製した。まず、上記のポリイミド樹脂成形品を５ｍｍ角程度の大きさにハサミで細かく切断し、ポリイミド樹脂粉砕品を得た。一方、撹拌機付きの１０００ｍＬ容器内で、イオン交換水６００ｇに水酸化カリウム４０ｇを溶解させてアルカリ水溶液を調製した。このアルカリ水溶液にポリイミド樹脂粉砕品１００ｇを加え、８０～９０℃で３時間加水分解処理を行い、粗製ポリイミド前駆体溶液を得た。
　続いて、粗製ポリイミド前駆体溶液に中和処理を施し、析出物を得た。この析出物に対してろ過処理を行い、さらにイオン交換水で洗浄した。さらに、中和塩化合物、及び、余剰な酸性化合物を除去したうえで、乾燥処理を行った。また、粉末状となるように粉砕処理を行った。このようにして、粉体状のポリイミド前駆体を調製した。
　参考：
（Ａ－２）ポリイミド前駆体（粉体状）
　・加水分解前のポリイミド樹脂成形品：
　　ポリイミド樹脂　製品名「カプトンＨ」（東レ・デュポン製）
　・加水分解条件：上記の加水分解条件と異なる
　参考：
（Ａ－３）ポリイミド前駆体（粉体状）
　・加水分解前のポリイミド樹脂成形品：
　　ポリイミド樹脂　製品名「カプトンＥＮ」（東レ・デュポン製）
　　　　　　　　　　　　　　図１の式（Ｊ）に示す分子構造のポリイミド樹脂
　・加水分解条件：上記の加水分解条件と異なる
（Ｂ）オキサゾリン化合物
　（Ｂ－１）高分子オキサゾリン化合物（オキサゾリン構造含有アクリルポリマー）
　　　　製品名「エポクロス　ＷＳ－５００」（日本触媒社製）
　　　　１－メトキシ－２－プロパノールを含む水溶液に溶解（固形分３９質量％）
　　　　オキサゾリン基量：４．５［ｍｍｏｌ／ｇ，固形分あたり］
　　　　分子量：Ｍｎ＝２万、Ｍｗ＝７万、Ｍｗ／Ｍｎ＝３．５
　（Ｂ－２）高分子オキサゾリン化合物（オキサゾリン構造含有アクリルポリマー）
　　　　製品名「エポクロス　ＷＳ－７００」（日本触媒社製）
　　　　水に溶解（固形分２５質量％）
　　　　オキサゾリン基量：４．５［ｍｍｏｌ／ｇ，固形分あたり］
　　　　分子量：Ｍｎ＝２万、Ｍｗ＝４万、Ｍｗ／Ｍｎ＝２．０
　（Ｂ－３）高分子オキサゾリン化合物（オキサゾリン構造含有アクリルポリマー）
　　　　製品名「エポクロス　ＷＳ－３００」（日本触媒社製）
　　　　水に溶解（固形分１０質量％）
　　　　オキサゾリン基量：７．７［ｍｍｏｌ／ｇ，固形分あたり］
　　　　分子量：Ｍｎ＝４万、Ｍｗ＝１２万、Ｍｗ／Ｍｎ＝３．０
（Ｃ）上記（Ｂ）の代替化合物（比較用化合物）
　（Ｃ－１）ポリカルボジイミド（ポリカルボジイミドに親水性セグメントを付与）
　　　　製品名「カルボジライト　Ｖ－０２－Ｌ２」（日清紡ケミカル社製）
　　　　水系溶媒に溶解（固形分４０質量％）
　（Ｃ－２）ポリカルボジイミド（ポリカルボジイミドに親水性セグメントを付与）
　　　　製品名「カルボジライト　Ｖ－０２」（日清紡ケミカル社製）
　　　　水系溶媒に溶解（固形分４０質量％）
　（Ｃ－３）ポリカルボジイミド（ポリカルボジイミドに親水性セグメントを付与）
　　　　製品名「カルボジライト　Ｖ－０４」（日清紡ケミカル社製）
　　　　水系溶媒に溶解（固形分４０質量％）
　（Ｃ－４）エポキシ樹脂（乳化状態　固形分７０質量％）
　　　　製品名「ＪＥＲ　Ｗ２８２１Ｒ７０」（三菱ケミカル社製）
　（Ｃ－５）エポキシ樹脂（乳化状態　固形分６７質量％）
　　　　製品名「ＪＥＲ　Ｗ３４３５Ｒ６７」（三菱ケミカル社製） Each raw material for producing the curable composition is described below.
<Main raw materials>
(A-1) polyimide precursor (powder)
・Polyimide resin molded product before hydrolysis:
Polyimide resin Product name “Kapton H” (manufactured by Toray DuPont)
Polyimide resin having a molecular structure shown in formula (A) in FIG. 1 Mass average molecular weight (Mw) after hydrolysis: 11,000
・Mw/Mn after hydrolysis: 1.6
The above (A-1) was prepared as follows. First, the polyimide resin molded product was finely cut into pieces of about 5 mm square with scissors to obtain pulverized polyimide resin products. On the other hand, an alkaline aqueous solution was prepared by dissolving 40 g of potassium hydroxide in 600 g of deionized water in a 1000 mL vessel equipped with a stirrer. 100 g of pulverized polyimide resin was added to this alkaline aqueous solution, and hydrolysis treatment was carried out at 80 to 90° C. for 3 hours to obtain a crude polyimide precursor solution.
Subsequently, the crude polyimide precursor solution was neutralized to obtain a deposit. The precipitate was filtered and washed with deionized water. Furthermore, after removing neutralized salt compounds and excess acidic compounds, drying treatment was performed. In addition, pulverization treatment was performed so as to form a powder. Thus, a powdery polyimide precursor was prepared.
reference:
(A-2) Polyimide precursor (powder)
・Polyimide resin molded product before hydrolysis:
Polyimide resin Product name “Kapton H” (manufactured by Toray DuPont)
・Hydrolysis conditions: Different from the above hydrolysis conditions Reference:
(A-3) Polyimide precursor (powder)
・Polyimide resin molded product before hydrolysis:
Polyimide resin Product name “Kapton EN” (manufactured by Toray DuPont)
Polyimide resin having a molecular structure shown in formula (J) in FIG. 1 Hydrolysis conditions: (B) oxazoline compound different from the above hydrolysis conditions (B-1) polymeric oxazoline compound (oxazoline structure-containing acrylic polymer)
Product name “Epocross WS-500” (manufactured by Nippon Shokubai Co., Ltd.)
Dissolved in an aqueous solution containing 1-methoxy-2-propanol (solid content 39 mass%)
Oxazoline group amount: 4.5 [mmol/g, per solid content]
Molecular weight: Mn = 20,000, Mw = 70,000, Mw/Mn = 3.5
(B-2) Polymeric oxazoline compound (oxazoline structure-containing acrylic polymer)
Product name “Epocross WS-700” (manufactured by Nippon Shokubai Co., Ltd.)
Dissolved in water (solid content 25% by mass)
Oxazoline group amount: 4.5 [mmol/g, per solid content]
Molecular weight: Mn = 20,000, Mw = 40,000, Mw/Mn = 2.0
(B-3) Polymeric oxazoline compound (oxazoline structure-containing acrylic polymer)
Product name “Epocross WS-300” (manufactured by Nippon Shokubai Co., Ltd.)
Dissolved in water (solid content 10% by mass)
Oxazoline group amount: 7.7 [mmol/g, per solid content]
Molecular weight: Mn = 40,000, Mw = 120,000, Mw/Mn = 3.0
(C) Substitute compound (comparative compound) of (B) above
(C-1) Polycarbodiimide (adding a hydrophilic segment to polycarbodiimide)
Product name “Carbodilite V-02-L2” (manufactured by Nisshinbo Chemical Co., Ltd.)
Dissolved in aqueous solvent (solid content 40% by mass)
(C-2) Polycarbodiimide (adding a hydrophilic segment to polycarbodiimide)
Product name “Carbodilite V-02” (manufactured by Nisshinbo Chemical Co., Ltd.)
Dissolved in aqueous solvent (solid content 40% by mass)
(C-3) Polycarbodiimide (adding a hydrophilic segment to polycarbodiimide)
Product name “Carbodilite V-04” (manufactured by Nisshinbo Chemical Co., Ltd.)
Dissolved in aqueous solvent (solid content 40% by mass)
(C-4) Epoxy resin (emulsified solid content 70% by mass)
Product name “JER W2821R70” (manufactured by Mitsubishi Chemical Corporation)
(C-5) Epoxy resin (emulsified solid content 67% by mass)
Product name “JER W3435R67” (manufactured by Mitsubishi Chemical Corporation)
［加水分解されて生じたポリイミド前駆体のＧＰＣチャート］
　ポリイミド樹脂の加水分解物であるポリイミド前駆体（Ａ－１）を、上述したゲルパーミエーションクロマトグラフィー（ＧＰＣ）測定の測定条件で測定したときのＧＰＣチャートを図２に示す。 [GPC chart of polyimide precursor produced by hydrolysis]
FIG. 2 shows a GPC chart when the polyimide precursor (A-1), which is a hydrolyzate of the polyimide resin, was measured under the above-described gel permeation chromatography (GPC) measurement conditions.
［加水分解前のポリイミド樹脂のＩＲチャート］
　ポリイミド前駆体（Ａ－１）を加水分解する前のポリイミド樹脂を、上述した分析条件及び解析方法で赤外分光分析したときの赤外分光スペクトル（ＩＲチャート）を図３に示す。
　また、ポリイミド前駆体（Ａ－３）を加水分解する前のポリイミド樹脂を、同様に分析したときの赤外分光スペクトル（ＩＲチャート）を図４に示す。 [IR chart of polyimide resin before hydrolysis]
FIG. 3 shows an infrared spectroscopic spectrum (IR chart) when the polyimide resin before hydrolysis of the polyimide precursor (A-1) was subjected to infrared spectroscopic analysis under the analysis conditions and analysis method described above.
FIG. 4 shows an infrared spectrum (IR chart) obtained by similarly analyzing the polyimide resin before hydrolysis of the polyimide precursor (A-3).
［加水分解されて生じたポリイミド前駆体のＩＲチャート（参考）］
　ポリイミド樹脂の加水分解物であるポリイミド前駆体（Ａ－１）を、上述した分析条件及び解析方法で赤外分光分析したときの赤外分光スペクトル（ＩＲチャート）を図５に示す。
　ポリイミド樹脂の加水分解物であるポリイミド前駆体（Ａ－２）を、同様に分析したときの赤外分光スペクトル（ＩＲチャート）を図６に示す。
　ポリイミド樹脂の加水分解物であるポリイミド前駆体（Ａ－３）を、同様に分析したときの赤外分光スペクトル（ＩＲチャート）を図７に示す。 [IR chart of polyimide precursor produced by hydrolysis (reference)]
FIG. 5 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-1), which is a hydrolyzate of the polyimide resin, was subjected to infrared spectroscopic analysis under the analysis conditions and analysis method described above.
FIG. 6 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-2), which is a hydrolyzate of the polyimide resin, was similarly analyzed.
FIG. 7 shows an infrared spectroscopic spectrum (IR chart) when the polyimide precursor (A-3), which is a hydrolyzate of the polyimide resin, was similarly analyzed.
　図５を基にして、上述した各ピーク高さの比を算出した結果は、以下の通りであった。
　　（Ｐ１／Ｐ２）：４．０４
　　（Ｐ１／Ｐ３）：４．９５
　　（Ｐ１／Ｐ４）：５．３５
　図６を基にして、上述した各ピーク高さの比を算出した結果は、以下の通りであった。
　　（Ｐ１／Ｐ２）：　２．８９
　　（Ｐ１／Ｐ３）：　８．００
　　（Ｐ１／Ｐ４）：１０．４６
　図７を基にして、上述した各ピーク高さの比を算出した結果は、以下の通りであった。
　　（Ｐ１／Ｐ２）：２．２７
　　（Ｐ１／Ｐ３）：９．０８
　　（Ｐ１／Ｐ４）：５．８９ Based on FIG. 5, the results of calculating the above-described peak height ratios were as follows.
(P1/P2): 4.04
(P1/P3): 4.95
(P1/P4): 5.35
Based on FIG. 6, the results of calculating the above-described peak height ratios were as follows.
(P1/P2): 2.89
(P1/P3): 8.00
(P1/P4): 10.46
Based on FIG. 7, the results of calculating the above-described peak height ratios were as follows.
(P1/P2): 2.27
(P1/P3): 9.08
(P1/P4): 5.89
（実施例１～９、比較例１～１３）
　上述した各原料などを以下の各表に示す配合量で混合し、（Ａ－１）を溶解させることによって、各実施例及び各比較例の硬化用組成物を製造した。各硬化用組成物の配合組成を表１に示す。なお、（Ａ）及び（Ｂ）の総量（固形分）が２０質量％濃度程度となるように各硬化用組成物を製造した。
　具体的には、撹拌機付きの容器にイオン交換水６８．１ｇ、ジエタノールアミン１１．６ｇを入れ、６０℃に加熱した。次に、上記の（Ａ）ポリイミド前駆体２０ｇを加え、６０分間撹拌した。続いて、規定量の（Ｂ）オキサゾリン環含有化合物若しくは（Ｃ）比較用化合物、及び、添加剤（レベリング剤、安定剤）を加え、また、必要に応じてイオン交換水を加え、硬化用組成物を調製した。
　なお、各表において、（Ｂ）及び（Ｃ）の配合量は、固形分換算量で示されている。 (Examples 1 to 9, Comparative Examples 1 to 13)
The above raw materials were mixed in the amounts shown in the following tables, and (A-1) was dissolved to prepare the curable compositions of Examples and Comparative Examples. Table 1 shows the composition of each curing composition. Each curable composition was produced such that the total amount (solid content) of (A) and (B) was about 20% by mass.
Specifically, 68.1 g of ion-exchanged water and 11.6 g of diethanolamine were placed in a container equipped with a stirrer and heated to 60°C. Next, 20 g of the polyimide precursor (A) was added and stirred for 60 minutes. Subsequently, a prescribed amount of (B) oxazoline ring-containing compound or (C) comparative compound, and additives (leveling agent, stabilizer) are added, and if necessary, deionized water is added to form a curing composition. prepared the product.
In addition, in each table, the blending amounts of (B) and (C) are shown in terms of solid content.
＜組成物の溶液性状＞
　硬化用組成物の配合組成（表１）で混合した溶液を２日間室温で保管した。その後の組成物の溶液性状を確認した。 <Solution Properties of Composition>
The mixed solution of the curing composition formulation (Table 1) was stored at room temperature for 2 days. After that, the solution properties of the composition were confirmed.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
＜硬化処理＞
　各実施例および各比較例の硬化用組成物をバーコーターを用いて、ポリイミドフィルム（カプトンH、東レ・デュポン社製）、及び、ステンレス板（ＳＵＳ３０４、ＴＰ技研社製）にそれぞれ塗布した。塗布後に６０℃で３０分間予備乾燥処理を実施し、その後、３００℃で３０分間の加熱により硬化処理を実施することによって、膜厚２０μｍの硬化塗膜（硬化物）を作製した。 <Hardening treatment>
Using a bar coater, the curable composition of each example and each comparative example was applied to a polyimide film (Kapton H, manufactured by Toray DuPont) and a stainless steel plate (SUS304, manufactured by TP Giken). After coating, a pre-drying treatment was performed at 60° C. for 30 minutes, and then a curing treatment was performed by heating at 300° C. for 30 minutes to prepare a cured coating film (cured product) having a film thickness of 20 μm.
＜硬化塗膜の均一性＞
　各実施例および各比較例の硬化用組成物をアルミ箔（ＵＡＣＪ製箔製）の上にバーコーターを用いて塗布した。塗布後に６０℃で３０分間予備乾燥し、その後、３００℃で３０分間の加熱により硬化処理を実施することによって、膜厚２０μｍの硬化塗膜（硬化物）を作製した。目視で観察することによって硬化塗膜の均一性を判定した。
　　良（〇）　　：褐色透明膜である
　　やや良（△）：わずかに濁りがある
　　不良（×）　　：濁りがある <Uniformity of cured coating>
The curable composition of each example and each comparative example was applied onto an aluminum foil (manufactured by UACJ Foil Corporation) using a bar coater. After coating, the composition was pre-dried at 60° C. for 30 minutes, and then cured by heating at 300° C. for 30 minutes to prepare a cured coating film (cured product) having a thickness of 20 μm. The uniformity of the cured coating was determined by visual observation.
Good (○): Brown transparent film Somewhat good (△): Slightly cloudy Poor (×): Cloudy
＜硬化塗膜の屈曲性（柔軟性）＞
　各実施例および各比較例の硬化塗膜面を上側に配置し、硬化塗膜面が外側となるように１８０度に折り曲げた後、元のように硬化塗膜面を平らに戻した。折り曲げた部分の塗膜に粘着テープ（ニチバン社製「セロテープ（登録商標）ＣＴ４０５ＡＰ－２４」）を貼り付けて剥がした。剥がれた塗膜の巾を測ることによって屈曲性を測定し、これを硬化塗膜の柔軟性の指標とした。なお、被着体として、ポリイミドフィルムを用いた。
　　良（〇）　　：１ｍｍ以下
　　やや良（△）：１～２ｍｍ
　　不良（×）　　：２ｍｍ以上 <Flexibility (flexibility) of cured coating>
The cured coating film surface of each example and each comparative example was placed on the upper side, bent 180 degrees so that the cured coating film surface was on the outside, and then the cured coating film surface was flattened as before. An adhesive tape (“Cellotape (registered trademark) CT405AP-24” manufactured by Nichiban Co., Ltd.) was attached to the coating film at the bent portion and then peeled off. Flexibility was measured by measuring the width of the peeled coating film and used as an index of the flexibility of the cured coating film. A polyimide film was used as an adherend.
Good (○): 1 mm or less Fairly good (△): 1 to 2 mm
Defective (x): 2 mm or more
＜硬化塗膜の密着性＞
　各実施例および各比較例の硬化塗膜に対してカッターナイフで碁盤目に切り込みを入れ、上記粘着テープによる剥離操作を行うことによって硬化塗膜の密着性を測定した。測定は、ＪＩＳ　Ｋ５６００－５－６：１９９９　塗料一般試験方法　第５部：塗膜の機械的性質　第６節：付着性（クロスカット法　いわゆる碁盤目試験）に準じて実施した。なお、被着体として、ポリイミドフィルム、及び、ＳＵＳをそれぞれ用いた。
　下記の判断基準に準じて、密着性を評価した。
　　良（〇）　　：残存数が９０～１００／１００ 
　　やや良（△）：残存数が５０～９０／１００ 
　　不良（×）　　：残存数が０～５０／１００ <Adhesion of cured coating>
The adhesiveness of the cured coating film of each example and each comparative example was measured by making cuts in a grid pattern with a cutter knife and performing a peeling operation with the adhesive tape. The measurement was carried out according to JIS K5600-5-6:1999 General Test Methods for Paints, Part 5: Mechanical properties of coating film, Section 6: Adhesion (cross-cut method, so-called cross-cut test). A polyimide film and SUS were used as adherends.
Adhesion was evaluated according to the following criteria.
Good (○): Remaining number is 90 to 100/100
Somewhat good (△): The number of remaining is 50 to 90/100
Defective (x): Remaining number is 0 to 50/100
　各硬化用組成物について、上記の各性能を評価した結果を、表２に示す。なお、比較例４～７の硬化塗膜については、その均一性が良好でないことを確認したため、その他の評価（屈曲性、密着性）を実施しなかった。 Table 2 shows the results of evaluating each of the above performances for each curing composition. It was confirmed that the uniformity of the cured coating films of Comparative Examples 4 to 7 was not good, so other evaluations (flexibility and adhesion) were not performed.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　実施例の硬化用組成物の硬化物（硬化塗膜）が良好な性能を発揮できる理由は、以下のように考えられる。実施例の硬化用組成物に加熱などの硬化処理が施されることによって、ポリイミド前駆体における複数のアミック酸構造の少なくとも一部がイミド化する。これにより、新たに環状ポリイミド構造が形成される。また、ポリイミド前駆体の一部のアミック酸構造におけるカルボキシ基、及び、ポリイミド前駆体の分子鎖末端におけるカルボキシ基が、オキサゾリン化合物のオキサゾリン環とアミドエステル結合することができる。これにより、ポリイミド前駆体と比較的多量のオキサゾリン化合物とを結合させることができる。カルボキシ基と結合せずに残存したオキサゾリン環は、被着体の表面に存在する極性基と親和性を有することから、硬化用組成物が硬化した硬化物（硬化樹脂、硬化塗膜など）は、被着体に対して良好な密着性を発揮できる。また、硬化物の割れを抑制でき、硬化物が柔軟性を有することができる。なお、硬化物は、均一性の点でも良好となる。 The reason why the cured product (cured coating film) of the curable composition of the example can exhibit good performance is considered as follows. By subjecting the curable composition of the example to a curing treatment such as heating, at least part of the plurality of amic acid structures in the polyimide precursor is imidized. As a result, a new cyclic polyimide structure is formed. Moreover, the carboxy group in the amic acid structure of a portion of the polyimide precursor and the carboxy group at the molecular chain end of the polyimide precursor can form an amide ester bond with the oxazoline ring of the oxazoline compound. Thereby, the polyimide precursor and a relatively large amount of the oxazoline compound can be bonded. Since the oxazoline ring remaining without bonding to the carboxy group has affinity with the polar group present on the surface of the adherend, the cured product (cured resin, cured coating film, etc.) obtained by curing the curable composition is , can exhibit good adhesion to the adherend. Moreover, cracking of the cured product can be suppressed, and the cured product can have flexibility. In addition, the cured product is also excellent in terms of uniformity.
　表１及び表２などの結果から把握されるように、実施例の硬化用組成物を硬化させた硬化塗膜は、均一性の点で良好であり、また、被着体に対する密着性が良好であり、屈曲性（即ち、柔軟性）の点でも良好であった。即ち、実施例の硬化用組成物を硬化させた硬化塗膜は、均一性と、柔軟性と、被着体に対する密着性と、を同時に兼ね備えていた。
　オキサゾリン化合物を含まない硬化用組成物、又は、オキサゾリン化合物の含有量が特定量未満の硬化用組成物では、硬化処理によって硬化した硬化塗膜がその内部応力を緩和できず、硬化塗膜の密着性や屈曲性が低くなったと考えられる。また、オキサゾリン化合物の含有量が所定量よりも多くなると、ポリイミド前駆体とオキサゾリン化合物との相溶性が低くなり、その結果、硬化塗膜の均一性が低下したと考えられる。
　なお、参考として示した上記の（Ａ－２）及び（Ａ－３）のポリイミド前駆体をそれぞれ含む各硬化用組成物も、良好な硬化塗膜を生成できるといえる。 As can be seen from the results in Tables 1 and 2, etc., the cured coating films obtained by curing the curable compositions of Examples have good uniformity and good adhesion to adherends. , and was also good in terms of bendability (that is, flexibility). That is, the cured coating film obtained by curing the curable composition of the example had uniformity, flexibility, and adhesion to the adherend at the same time.
In a curable composition that does not contain an oxazoline compound or a curable composition that contains less than a specific amount of an oxazoline compound, the internal stress of the cured coating film cured by the curing treatment cannot be relaxed, and the adhesion of the cured coating film is reduced. This is thought to be due to the lower flexibility and flexibility. Moreover, it is thought that when the content of the oxazoline compound exceeds a predetermined amount, the compatibility between the polyimide precursor and the oxazoline compound is lowered, resulting in a decrease in the uniformity of the cured coating film.
Incidentally, it can be said that each curing composition containing the above-mentioned polyimide precursors (A-2) and (A-3) shown as a reference can also form a good cured coating film.
　本発明の硬化用組成物は、例えば、耐熱性、電気絶縁性、耐薬品性などの性能を有する硬化物を作製するために、例えば金属、樹脂成型品、繊維、フィルムに塗布されて使用される。 The curable composition of the present invention is applied to, for example, metals, resin moldings, fibers, and films in order to produce cured products having properties such as heat resistance, electrical insulation, and chemical resistance. be.

Claims (5)

  1. 　ポリイミド樹脂のイミド結合の一部が加水分解されたポリイミド前駆体と、
    　オキサゾリン環を分子中に有するオキサゾリン化合物とを含み、
    　前記ポリイミド前駆体の繰り返し構造単位１ｍｏｌに対する、前記オキサゾリン化合物の前記オキサゾリン環の量が、０．２０ｍｏｌ以上１．６０ｍｏｌ以下である、硬化用組成物。     A polyimide precursor in which a part of the imide bond of the polyimide resin is hydrolyzed,
    and an oxazoline compound having an oxazoline ring in the molecule,
    The curable composition, wherein the amount of the oxazoline ring of the oxazoline compound is 0.20 mol or more and 1.60 mol or less per 1 mol of the repeating structural unit of the polyimide precursor.
  2. 　前記オキサゾリン化合物が高分子化合物である、請求項１に記載の硬化用組成物。 The curable composition according to claim 1, wherein the oxazoline compound is a polymer compound.
  3. 　水性溶媒をさらに含む、請求項１又は２に記載の硬化用組成物。 The curable composition according to claim 1 or 2, further comprising an aqueous solvent.
  4. 　前記ポリイミド前駆体がベンゼン環を分子中に有し、
    　前記ポリイミド前駆体を赤外分光分析した赤外分光スペクトルが、ベンゼン環による波数１５００ｃｍ－１の吸収ピークＰ１と、イミド基による波数１３７５ｃｍ－１の吸収ピークＰ２と、を示し、
    　前記吸収ピークＰ２の高さに対する前記吸収ピークＰ１の高さの比（Ｐ１／Ｐ２）が、２以上１０以下である、請求項１乃至３のいずれか１項に記載の硬化用組成物。     The polyimide precursor has a benzene ring in the molecule,
    An infrared spectroscopic spectrum obtained by infrared spectroscopic analysis of the polyimide precursor shows an absorption peak P1 at a wave number of 1500 cm −1 due to a benzene ring and an absorption peak P2 at a wave number of 1375 cm −1 due to an imide group,
    The curable composition according to any one of claims 1 to 3, wherein the ratio (P1/P2) of the height of the absorption peak P1 to the height of the absorption peak P2 is 2 or more and 10 or less.
  5. 　請求項１乃至４のいずれか１項に記載された硬化用組成物が硬化した硬化物。 A cured product obtained by curing the curable composition according to any one of claims 1 to 4.
PCT/JP2022/017330 2021-04-09 2022-04-08 Curable composition and cured product WO2022215743A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2023513053A JPWO2022215743A1 (en) 2021-04-09 2022-04-08

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-066611 2021-04-09
JP2021066611 2021-04-09

Publications (1)

Publication Number Publication Date
WO2022215743A1 true WO2022215743A1 (en) 2022-10-13

Family

ID=83546166

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/017330 WO2022215743A1 (en) 2021-04-09 2022-04-08 Curable composition and cured product

Country Status (2)

Country Link
JP (1) JPWO2022215743A1 (en)
WO (1) WO2022215743A1 (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04506942A (en) * 1989-08-15 1992-12-03 フォスター―ミラー・インコーポレイテッド Film-based composite structures for ultralight SDI systems
JPH06324493A (en) * 1993-05-13 1994-11-25 Toray Ind Inc Positive photosensitive polyimide precursor composition
JP2008040473A (en) * 2006-07-10 2008-02-21 Chisso Corp Liquid crystal aligning agent, liquid crystal alignment layer, and liquid crystal display element
WO2012098734A1 (en) * 2011-01-18 2012-07-26 旭化成イーマテリアルズ株式会社 Resin composition, cured object, resin film, and wiring board
JP2014118519A (en) * 2012-12-18 2014-06-30 Kaneka Corp Polyimide resin solution
JP2016200798A (en) * 2015-04-08 2016-12-01 Jsr株式会社 Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, liquid crystal element, method for manufacturing liquid crystal element and compound
WO2017110976A1 (en) * 2015-12-25 2017-06-29 日産化学工業株式会社 Liquid crystal display element, liquid crystal optical element, and composition for liquid crystal structure stabilization film
JP2020123448A (en) * 2019-01-29 2020-08-13 三菱ケミカル株式会社 Resin composition for insulating coating material, and insulating coating material

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04506942A (en) * 1989-08-15 1992-12-03 フォスター―ミラー・インコーポレイテッド Film-based composite structures for ultralight SDI systems
JPH06324493A (en) * 1993-05-13 1994-11-25 Toray Ind Inc Positive photosensitive polyimide precursor composition
JP2008040473A (en) * 2006-07-10 2008-02-21 Chisso Corp Liquid crystal aligning agent, liquid crystal alignment layer, and liquid crystal display element
WO2012098734A1 (en) * 2011-01-18 2012-07-26 旭化成イーマテリアルズ株式会社 Resin composition, cured object, resin film, and wiring board
JP2014118519A (en) * 2012-12-18 2014-06-30 Kaneka Corp Polyimide resin solution
JP2016200798A (en) * 2015-04-08 2016-12-01 Jsr株式会社 Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, liquid crystal element, method for manufacturing liquid crystal element and compound
WO2017110976A1 (en) * 2015-12-25 2017-06-29 日産化学工業株式会社 Liquid crystal display element, liquid crystal optical element, and composition for liquid crystal structure stabilization film
JP2020123448A (en) * 2019-01-29 2020-08-13 三菱ケミカル株式会社 Resin composition for insulating coating material, and insulating coating material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HINO SEIICHI: "Heat resistant composite materials. 1. Addition type aromatic polyimide base composite materials", JOURNAL OF THERMOSETTING PLASTICS, vol. 10, no. 1, 10 March 1989 (1989-03-10), pages 39 - 41, XP055976095, ISSN: 0388-4384, DOI: 10.11364/networkpolymer1980.10.39 *

Also Published As

Publication number Publication date
JPWO2022215743A1 (en) 2022-10-13

Similar Documents

Publication Publication Date Title
US9339992B2 (en) Low-thermal-expansion block polyimide, precursor thereof, and use thereof
JP4957583B2 (en) Solvent-soluble polyimide copolymer and polyimide varnish containing the same
KR101505890B1 (en) Thermosetting resin composition and cured film
US10421881B2 (en) PAI-based coating composition
JP6413434B2 (en) Polyimide precursor composition, method for producing polyimide precursor, polyimide molded body, and method for producing polyimide molded body
JP2015117278A (en) Functionalized polyimide resin and epoxy resin composition including the same
WO2008041723A1 (en) Two-part thermocurable polyimide resin composition and cured product thereof
JP2016124956A (en) Polyamideimide precursor composition, polyamideimide molded article, and method for preparing polyamideimide molded article
JP2007246897A (en) Heat-resistant resin paste, method for producing heat-resistant resin paste and semiconductor device having insulation film or protection film derived from heat-resistant resin paste
JP5109374B2 (en) Polyamideimide resin solution and production method thereof, resin composition and coating composition
JP6496993B2 (en) Polyimide precursor composition, method for producing polyimide precursor, polyimide molded body, and method for producing polyimide molded body
TWI432487B (en) Flammable polyimide silicone resin composition
WO2022215743A1 (en) Curable composition and cured product
CN113166413B (en) Polyimide resin composition and polyimide film
JP2017145344A (en) Polyimide, polyimide solution, resin film, polyimide composition, crosslinked polyimide, coverlay film, and circuit board
JP2009286826A (en) Heat-resistant resin composition and paint containing the same as paint component
KR102261516B1 (en) Polyimide resin composition, adhesive composition, film-shaped adhesive material, adhesive sheet, copper foil with resin, copper clad laminate, printed wiring board and polyimide film
CN114940757A (en) Polyimide resin composition, adhesive composition, and related articles
JP2019026769A (en) Polyamide-imide resin liquid and method for producing the same
JP5477327B2 (en) Method for producing polyimide resin
JP7144182B2 (en) Curable resin composition, cured product, adhesive and adhesive film
JP5630651B2 (en) Articles having a heat-resistant paint and a film formed by curing the heat-resistant paint.
JP2021025031A (en) Heat-curable cyclic imide resin composition
JP2010037401A (en) Polyimide, production method of the same, and production method of polyimide film
CN113614173B (en) Polyamide-imide resin composition and process for producing polyamide-imide resin

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22784725

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2023513053

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22784725

Country of ref document: EP

Kind code of ref document: A1