Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
  • C08G73/14—Polyamide-imides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2379/00—Characterised by the use 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 C08J2361/00 - C08J2377/00
  • C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors

Definitions

• the present invention relates to a method for producing a polyimide film.
• polyimide resin Various uses of polyimide resin are being considered in fields such as electrical and electronic parts. For example, it is desired to replace glass substrates used in image display devices such as liquid crystal displays and OLED displays with plastic substrates for the purpose of making the devices lighter and more flexible, and polyimide films are suitable as plastic substrates. Research is underway. Polyimide films for such uses are required to have various performances.
• Patent Document 1 describes two types of specific amic acid structures for the purpose of obtaining a polyimide film with low residual stress, little warpage, low yellowness, and high elongation.
• Polyimide precursors are disclosed that are characterized by containing units in specific proportions.
• polyimide films for specific uses are required to have colorless transparency, high tensile elongation, and low residual stress.
• the TFT device type is LTPS (Low Temperature Polysilicon TFT)
• the process temperature exceeds 400°C
• the polyimide substrate is required to have the heat resistance to withstand multiple treatments at high temperatures of 400°C or higher. It is required to maintain colorless transparency and high tensile elongation even under a long thermal history.
• polyimide precursors develop high elongation and heat resistance through thermal imidization and molecular weight increase during drying.
• Patent Document 1 discloses a technique for reducing residual stress and yellowness, but it is still insufficient as a method for stably producing such a polyimide film, especially due to its low transparency. It has not been possible to obtain a polyimide film that maintains yellowness and has excellent heat resistance.
• the present invention was made in view of these circumstances, and an object of the present invention is to sufficiently achieve the imidization reaction and increase in molecular weight of a polyimide precursor, and to achieve high colorless transparency and high elongation rate. It is an object of the present invention to provide a method for producing a polyimide film which can obtain a polyimide film having the following characteristics and excellent heat resistance.
• the present inventors have found that the above problems can be solved by removing the solvent from a polyimide precursor varnish having a diamine-derived structural unit with a specific ionization potential, and holding it stepwise at multiple temperatures to imidize it. He discovered this and completed his invention.
• Step 1 of removing the solvent from a varnish containing a polyimide precursor having a polyamic acid moiety and a solvent at 50 to 120 °C, and drying it at 300 to 400 °C for 10 to 120 minutes, and then drying at 420 to 500 °C.
• step 2 of imidizing by holding at °C, the polyamic acid portion has a structural unit derived from a tetracarboxylic dianhydride and a structural unit derived from a diamine, and the polyamic acid portion has a structural unit derived from a diamine.
• a method for producing a polyimide film wherein the provided diamine contains a diamine having an ionization potential of 7.10 eV or more.
• the tetracarboxylic dianhydride providing the structural unit derived from the tetracarboxylic dianhydride includes a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less.
• a 1 is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO 2 -, -CO-, -CH 2 -, -C( It may have at least one selected from the group consisting of CH 3 ) 2 -, -C 2 H 4 O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S-.
• B 1 is a group represented by the above general formula (2)
• X 1 and X 2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.
• Y 1 and Y 2 each independently represent a single bond, a group represented by -COO-, or a group represented by -OCO-.
• R 1 , R 2 and R 3 each independently represent an organic group having 1 to 20 carbon atoms.
• h, i, j, and k are integers from 0 to 4.
• the yellow index of the polyimide film is less than 30 when the thickness is 10 ⁇ m, and the tensile strength when a 10 ⁇ m thick polyimide film is subjected to a tensile test with a test piece size of 10 mm x 70 mm and a distance between chucks of 50 mm.
• a polyimide film that can sufficiently achieve the imidization reaction and increase the molecular weight of a polyimide precursor, and obtain a polyimide film that has high colorless transparency, high elongation rate, and excellent heat resistance.
• a manufacturing method can be provided.
• the method for producing a polyimide film of the present invention includes Step 1 of removing the solvent from a varnish containing a polyimide precursor having a polyamic acid moiety and a solvent at 50 to 120°C, and drying it at 300 to 400°C for 10 to 120 minutes.
• the polyamic acid part After holding, it has a step 2 of imidizing by holding at 420 to 500 ° C., the polyamic acid part has a structural unit derived from a tetracarboxylic dianhydride and a structural unit derived from a diamine,
• the present invention is a method for producing a polyimide film containing a diamine that provides a structural unit derived from a diamine and has an ionization potential of 7.10 eV or more.
• Step 1 is a step of removing the solvent from a varnish containing a polyimide precursor having a polyamic acid moiety and a solvent at 50 to 120°C, and drying the varnish, in which the polyamic acid moiety is derived from tetracarboxylic dianhydride.
• the diamine that has a unit and a structural unit derived from a diamine and provides the structural unit derived from the diamine includes a diamine having an ionization potential of 7.10 eV or more.
• the polyimide precursor having a polyamic acid moiety contained in the varnish used in Step 1 has a polyamic acid moiety, and the polyamic acid moiety has a structural unit derived from a tetracarboxylic dianhydride and a structural unit derived from a diamine.
• the diamine providing the structural unit derived from the diamine contains a diamine having an ionization potential of 7.10 eV or more and becomes a polyimide after imidization in step 2.
• the polyimide precursor having a polyamic acid moiety is preferably at least one selected from the group consisting of polyamic acid and imide-amic acid copolymer, and more preferably imide-amic acid copolymer.
• the imide-amic acid copolymer is a copolymer having an amic acid part (polyamic acid part) and an imide part (polyimide part) in one molecule.
• Polyamic acid is a polymer that has only an amic acid moiety (polyamic acid moiety) and no imide moiety (polyimide moiety) as a structure that becomes polyimide after imidization.
• the polyamic acid part has a structural unit derived from a tetracarboxylic dianhydride and a structural unit derived from a diamine, and the diamine providing the structural unit derived from the diamine is a diamine having an ionization potential of 7.10 eV or more. include.
• the structural unit derived from the tetracarboxylic dianhydride constituting the polyamic acid moiety is hereinafter also referred to as "structural unit AA.”
• the tetracarboxylic dianhydride that provides the structural unit derived from tetracarboxylic dianhydride (constituent unit AA) preferably includes a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less.
• the reason why the obtained polyimide film has low colorless transparency is the ease of charge movement within the molecule.
• the higher the electron affinity (Ea) of the tetracarboxylic dianhydride used as a raw material the easier the charge transfer will be, and the resulting polyimide film will have lower colorless transparency. Therefore, in order to make the polyimide film highly colorless and transparent, it is considered that the lower the electron affinity (Ea) of the tetracarboxylic dianhydride is, the better.
• the lower the electron affinity (Ea) of the tetracarboxylic dianhydride used as a raw material the lower the reactivity.
• the tetracarboxylic dianhydride that provides the structural unit derived from tetracarboxylic dianhydride preferably contains a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less, and more preferably has an electron affinity of 2.5 eV or less. It contains a tetracarboxylic dianhydride having an affinity of 2.4 eV or less, more preferably a tetracarboxylic dianhydride having an electron affinity of 2.3 eV or less.
• the Ea of the tetracarboxylic dianhydride was determined by the DFT method using Gaussian 16W, B3LYP using the unrestricted Hartree-Fock method as a functional, and 6-311++G (d, p ), and the structural parameters of each tetracarboxylic dianhydride are values obtained using those optimized on the B3LYP/6-311G(d) basis using the restricted Hartree-Fock method.
• the electron affinity of the tetracarboxylic dianhydride is one because the two acid dianhydride groups have the same electron affinity.
• the structural unit AA preferably includes a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less, more preferably derived from a tetracarboxylic dianhydride having an electron affinity of 2.4 eV or less. It further preferably contains a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.3 eV or less.
• the compound providing a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less preferably a compound represented by the following formula (a1), a compound represented by the formula (a2), and It is at least one selected from the group consisting of compounds represented by the following formula (a3), and more preferably a compound represented by the following formula (a1).
• the compound represented by formula (a1) is 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Ea: 2.24 eV).
• the compound represented by formula (a2) is 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) (Ea: 1.94 eV).
• the compound represented by formula (a3) is spiro[11H-difuro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7, 9-Tetron (SFDA) (Ea: 2.08 eV).
• the structural unit AA may include a structural unit other than the structural unit derived from the compound represented by formula (a1) or the structural unit derived from the compound represented by formula (a2).
• the total ratio of the structural unit derived from the compound represented by formula (a1) and the structural unit derived from the compound represented by formula (a2) in the structural unit AA is preferably 45 mol% or more, more preferably is 70 mol% or more, more preferably 90 mol% or more, particularly preferably 99 mol% or more.
• the upper limit of the ratio is not particularly limited and is 100 mol% or less.
• the structural unit AA preferably contains at least one selected from the group consisting of a structural unit derived from a compound represented by formula (a1) and a compound represented by formula (a2), and It is more preferable to include a structural unit derived from a compound represented by: Moreover, it is more preferable that the structural unit AA is at least one selected from the group consisting of a structural unit derived from a compound represented by formula (a1) and a compound represented by formula (a2), ) is more preferably a structural unit derived from a compound represented by.
• the ratio of each structural unit in the structural unit AA may be There is no limit and any ratio can be used.
• the structural unit derived from diamine constituting the polyamic acid moiety is also referred to as "constituent unit AB" hereinafter.
• the diamine that provides the structural unit derived from diamine (structural unit AB) includes a diamine whose ionization potential is 7.10 eV or more.
• the reason why the obtained polyimide film has low colorless transparency is the ease of charge movement within the molecule.
• the lower the ionization potential (Ip) of the diamine used as a raw material the easier the charge transfer will be, and the resulting polyimide film will have lower colorless transparency. Therefore, in order to make the polyimide film highly colorless and transparent, it is considered that the ionization potential (Ip) of the diamine is preferably higher.
• the higher the ionization potential (Ip) of the diamine used as a raw material the lower the reactivity. Therefore, if thermal imidization is not performed under appropriate drying conditions, sufficient thermal imidization and increase in molecular weight will not proceed, and colorless transparency may be impaired.
• the production method of the present invention even if a raw material that is effective in achieving high colorless transparency but has low reactivity as described above is used, it can be thermally imidized sufficiently and the molecular weight can further increase. It is believed that the resulting polyimide film is highly colorless and transparent, and also has high elongation and heat resistance.
• the diamine providing the structural unit derived from diamine (structural unit AB) preferably contains a diamine having an ionization potential (Ip) of 7.10 eV or more, more preferably a diamine having an ionization potential (Ip) of 7.20 eV or more. , more preferably a diamine having an ionization potential (Ip) of 7.30 eV or more.
• the ionization potential (Ip) of the diamine was determined by the DFT method using Gaussian 16W, B3LYP using the unrestricted Hartree-Fock method as the functional, and 6-311++G (d, p) as the basis function constituting the molecular orbital.
• the ionization potential (Ip) of the diamine is one because the ionization potentials (Ip) of the two amino groups are the same.
• the ionization potentials (Ip) of the two amino groups are different, so there are two ionization potential values.
• the ionization potential (Ip) of the diamine is 7.10 eV or more.
• the structural unit AB preferably includes a structural unit derived from a diamine having an ionization potential (Ip) of 7.10 eV or more, more preferably a structural unit derived from a diamine whose ionization potential (Ip) is 7.20 eV or more. and more preferably contains a structural unit derived from a diamine having an ionization potential (Ip) of 7.30 eV or more.
• a compound that provides a structural unit derived from a diamine having an ionization potential (Ip) of 7.10 eV or more preferably a compound represented by the following formula (b1), a compound represented by the formula (b2), and a compound represented by the formula ( It is at least one selected from the group consisting of compounds represented by b3), and more preferably a compound represented by the following formula (b1).
• the compound represented by formula (b1) is 4-aminophenyl-4-aminobenzoate (4-BAAB) (Ip: 7.59 eV and 7.68 eV).
• the compound represented by formula (b2) is 2,2'-bis(trifluoromethyl)benzidine (TFMB) (Ip: 7.55 eV).
• the compound represented by formula (b3) is 1,4-bis(4-aminobenzoyloxy)benzene (ABHQ) (Ip: 7.64 eV).
• the structural unit AB may include a structural unit other than the structural unit derived from the compound represented by formula (b1) or the structural unit derived from the compound represented by formula (b2).
• the total ratio of the structural unit derived from the compound represented by formula (b1) and the structural unit derived from the compound represented by formula (b2) in structural unit AB is preferably 45 mol% or more, more preferably is 70 mol% or more, more preferably 90 mol% or more, particularly preferably 99 mol% or more.
• the upper limit of the ratio is not particularly limited and is 100 mol% or less.
• the structural unit AB preferably contains at least one selected from the group consisting of a structural unit derived from a compound represented by formula (b1) and a compound represented by formula (b2), and It is more preferable to include a structural unit derived from a compound represented by: Moreover, it is more preferable that the structural unit AB is at least one selected from the group consisting of a structural unit derived from a compound represented by formula (b1) and a compound represented by formula (b2); ) is more preferably a structural unit derived from a compound represented by.
• the ratio of each structural unit in the structural unit AB is particularly determined. There is no limit and any ratio can be used.
• the polyimide precursor preferably contains a repeating unit represented by the following formula (1). Since the repeating unit represented by the following formula (1) is an amic acid moiety (polyamic acid moiety), whether the polyimide precursor is a polyamic acid or an imide-amic acid copolymer, included.
• a 1 is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO 2 -, -CO-, -CH 2 -, -C( It may have at least one selected from the group consisting of CH 3 ) 2 -, -C 2 H 4 O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S-.
• B 1 is a group represented by the above general formula (2), and X 1 and X 2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. be.
• Y 1 and Y 2 each independently represent a single bond, a group represented by -COO-, or a group represented by -OCO-.
• R 1 , R 2 and R 3 each independently represent an organic group having 1 to 20 carbon atoms.
• h, i, j, and k are integers from 0 to 4.
• a 1 is a tetravalent aromatic group having 4 to 39 carbon atoms, and bonding groups include -O-, -SO 2 -, -CO-, -CH 2 -, -C( It may have at least one selected from the group consisting of CH 3 ) 2 -, -C 2 H 4 O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S-. .
• a 1 is tetracarboxylic dianhydride with two dicarboxylic anhydride moieties (four carboxy group moieties) removed, and A 1 and the four carbonyl groups bonded to it are derived from tetracarboxylic dianhydride.
• the term "tetravalent aromatic group” means that all four carbons bonded to the imide group are aromatic carbons.
• the above-mentioned bonding group refers to a bonding group that bonds each aromatic ring when A 1 contains two or more aromatic rings. Note that the bonding group is not limited to these. It is preferable that A 1 be an aromatic group because the heat resistance of the polyimide will be improved.
• a 1 is a tetravalent aromatic group having 4 to 39 carbon atoms, preferably a group represented by the following formula (3), more preferably a group represented by the following formula (3a) It is the basis.
• X 1 and X 2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, preferably a hydrogen atom.
• B 1 is a group represented by the following general formula (2).
• Y 1 and Y 2 each independently represent a group represented by -COO- or a group represented by -OCO-.
• R 1 , R 2 , and R 3 each independently represent an organic group having 1 to 20 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a tri-carbon group. It is a fluoromethyl group, preferably a hydrogen atom.
• h, i, j, and k are integers from 0 to 4, preferably 0.
• a group represented by formula (2a) below is preferred.
• Y 1 and Y 2 each independently represent a group represented by -COO- or a group represented by -OCO-.
• R 1 , R 2 and R 3 each independently represents an organic group having 1 to 20 carbon atoms.h, i, j, and k are integers of 0 to 4.
• the mass ratio of the amic acid moiety to the polyamic acid is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more. It is still more preferably 82% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and there is no upper limit. It is not more than 100% by mass.
• the molar ratio of the amic acid moiety to the polyamic acid is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% or more. It is still more preferably 82 mol% or more, even more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and there is no upper limit. It is not more than 100 mol%.
• the imide-amic acid copolymer has an amic acid part (polyamic acid part) and an imide part (polyimide part) in one molecule.
• the amic acid part (polyamic acid part) is the same as the above-mentioned [polyamic acid], and the preferable structure is also the same. Therefore, the imide portion (polyimide portion) will be explained below.
• the polyimide portion has a structural unit derived from tetracarboxylic dianhydride and a structural unit derived from diamine.
• the structural unit derived from tetracarboxylic dianhydride constituting the polyimide portion is also referred to as "structural unit IA" hereinafter.
• the tetracarboxylic dianhydride that provides the structural unit derived from tetracarboxylic dianhydride (structural unit IA) preferably includes a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less.
• the reason why the obtained polyimide film has low colorless transparency is the ease of charge movement within the molecule.
• the higher the electron affinity (Ea) of the tetracarboxylic dianhydride used as a raw material the easier the charge transfer will be, and the resulting polyimide film will have lower colorless transparency. Therefore, in order to make the polyimide film highly colorless and transparent, it is considered that the lower the electron affinity (Ea) of the tetracarboxylic dianhydride is, the better.
• the tetracarboxylic dianhydride that provides the structural unit derived from tetracarboxylic dianhydride preferably contains a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less, and more preferably has an electron affinity of 2.5 eV or less. It contains a tetracarboxylic dianhydride having an affinity of 2.4 eV or less, more preferably a tetracarboxylic dianhydride having an electron affinity of 2.3 eV or less.
• the Ea of the tetracarboxylic dianhydride was determined by the DFT method using Gaussian 16W, B3LYP using the unrestricted Hartree-Fock method as a functional, and 6-311++G (d, p ), and the structural parameters of each tetracarboxylic dianhydride are values obtained using those optimized on the B3LYP/6-311G(d) basis using the restricted Hartree-Fock method.
• the electron affinity of the tetracarboxylic dianhydride is one because the two acid dianhydride groups have the same electron affinity.
• the structural unit IA preferably includes a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less, more preferably derived from a tetracarboxylic dianhydride having an electron affinity of 2.4 eV or less. It further preferably contains a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less.
• the compound providing a structural unit derived from a tetracarboxylic dianhydride having an electron affinity of 2.5 eV or less preferably a compound represented by the following formula (a1), a compound represented by the formula (a2), and It is at least one selected from the group consisting of compounds represented by formula (a3), and more preferably a compound represented by formula (a2) below.
• the compound represented by formula (a1) is 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Ea: 2.24 eV).
• the compound represented by formula (a2) is 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) (Ea: 1.94 eV).
• the compound represented by formula (a3) is spiro[11H-difuro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7, 9-Tetron (SFDA) (Ea: 2.08 eV).
• the structural unit IA may include a structural unit other than the structural unit derived from the compound represented by formula (a1) or the structural unit derived from the compound represented by formula (a2).
• the total ratio of the structural unit derived from the compound represented by formula (a1) and the structural unit derived from the compound represented by formula (a2) in the structural unit IA is preferably 45 mol% or more, more preferably is 70 mol% or more, more preferably 90 mol% or more, particularly preferably 99 mol% or more.
• the upper limit of the ratio is not particularly limited and is 100 mol% or less.
• the structural unit IA contains at least one selected from the group consisting of a structural unit derived from a compound represented by formula (a1) and a compound represented by formula (a2).
• the structural unit IA is at least one selected from the group consisting of a structural unit derived from a compound represented by formula (a1) and a compound represented by formula (a2); ) is more preferably a structural unit derived from a compound represented by.
• the structural unit IA contains a structural unit derived from a compound represented by formula (a1) and a structural unit derived from a compound represented by formula (a2), the ratio of each structural unit in the structural unit IA may be There is no limit and any ratio can be used.
• the structural unit derived from diamine constituting the polyimide portion is also referred to as "structural unit IB" hereinafter.
• the diamine that provides the structural unit derived from diamine (structural unit IB) preferably includes a diamine having an ionization potential of 7.10 eV or more.
• the reason why the obtained polyimide film has low colorless transparency is the ease of charge movement within the molecule.
• the diamine providing the structural unit derived from diamine preferably includes a diamine having an ionization potential (Ip) of 7.10 eV or more, more preferably a diamine having an ionization potential (Ip) of 7.20 eV or more. , more preferably a diamine having an ionization potential (Ip) of 7.30 eV or more.
• the ionization potential (Ip) of the diamine was determined by the DFT method using Gaussian 16W, B3LYP using the unrestricted Hartree-Fock method as the functional, and 6-311++G (d, p) as the basis function constituting the molecular orbital.
• the ionization potential (Ip) of the diamine is one because the ionization potentials (Ip) of the two amino groups are the same.
• the ionization potentials (Ip) of the two amino groups are different, so there are two ionization potential values.
• the ionization potential (Ip) of the diamine is 7.10 eV or more.
• the structural unit IB preferably includes a structural unit derived from a diamine having an ionization potential (Ip) of 7.10 eV or more, more preferably a structural unit derived from a diamine whose ionization potential (Ip) is 7.20 eV or more. and more preferably contains a structural unit derived from a diamine having an ionization potential (Ip) of 7.30 eV or more.
• a compound that provides a structural unit derived from a diamine having an ionization potential (Ip) of 7.10 eV or more preferably a compound represented by the following formula (b1), a compound represented by the formula (b2), and a compound represented by the formula ( It is at least one selected from the group consisting of compounds represented by b3), and more preferably a compound represented by the following formula (b1).
• the compound represented by formula (b1) is 4-aminophenyl-4-aminobenzoate (4-BAAB) (Ip: 7.59 eV and 7.68 eV).
• the compound represented by formula (b2) is 2,2'-bis(trifluoromethyl)benzidine (TFMB) (Ip: 7.55 eV).
• the compound represented by formula (b3) is 1,4-bis(4-aminobenzoyloxy)benzene (ABHQ) (Ip: 7.64 eV).
• the structural unit IB may include a structural unit other than the structural unit derived from the compound represented by formula (b1) or the structural unit derived from the compound represented by formula (b2).
• the total ratio of the structural unit derived from the compound represented by formula (b1) and the structural unit derived from the compound represented by formula (b2) in structural unit IB is preferably 45 mol% or more, more preferably is 70 mol% or more, more preferably 90 mol% or more, particularly preferably 99 mol% or more.
• the upper limit of the ratio is not particularly limited and is 100 mol% or less.
• the structural unit IB preferably contains at least one selected from the group consisting of a structural unit derived from a compound represented by formula (b1) and a compound represented by formula (b2), and It is more preferable to include a structural unit derived from a compound represented by: Moreover, it is more preferable that the structural unit IB is at least one selected from the group consisting of a structural unit derived from a compound represented by formula (b1) and a compound represented by formula (b2); ) is more preferably a structural unit derived from a compound represented by.
• the ratio of each structural unit in the structural unit IB may be There is no limit and any ratio can be used.
• the imide-amic acid copolymer used as the polyimide precursor preferably contains a repeating unit represented by the following formula (4).
• a 2 is at least one selected from the group consisting of the group represented by the above formula (5) and the group represented by the above formula (6)
• B 2 is the above general formula ( It is a group represented by 2).
• Y 1 and Y 2 each independently represent a single bond, a group represented by -COO-, or a group represented by -OCO-.
• R 1 , R 2 and R 3 each independently represent an organic group having 1 to 20 carbon atoms.
• h, i, j, and k are integers from 0 to 4.
• a 2 is at least one selected from the group consisting of the group represented by the above formula (5) and the above formula (6), preferably the above formula (5). It is a group represented by A 2 may be different from or the same as A 1 in formula (1), but is preferably a tetravalent aromatic group having 4 to 39 carbon atoms and different from A 1 .
• A2 is tetracarboxylic dianhydride with two dicarboxylic anhydride moieties (four carboxy group moieties) removed, and A2 and the four carbonyl groups bonded to it are derived from tetracarboxylic dianhydride. It is a constituent unit. It is preferable that A 2 be a group represented by formula (5) or a group represented by formula (6) because the polyimide will have good heat resistance.
• B 2 is a group represented by the following general formula (2).
• Y 1 and Y 2 each independently represent a group represented by -COO- or a group represented by -OCO-.
• R 1 , R 2 , and R 3 each independently represent an organic group having 1 to 20 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a tri-carbon group. It is a fluoromethyl group, preferably a hydrogen atom.
• h, i, j, and k are integers from 0 to 4, preferably 0.
• a group represented by formula (2a) below is preferred.
• Y 1 and Y 2 each independently represent a group represented by -COO- or a group represented by -OCO-.
• R 1 , R 2 and R 3 each independently represents an organic group having 1 to 20 carbon atoms.h, i, j, and k are integers of 0 to 4.
• the molar ratio [imide/amic acid] of the imide moiety (the repeating unit represented by formula (4)) and the amic acid part (the repeating unit represented by the formula (1)) is: From the viewpoint of low yellowness, high heat resistance, and elongation rate, it is preferably 10/90 to 40/60, more preferably 10/90 to 30/70, and even more preferably 15/85 to 30/70. be.
• the total mass ratio of the imide part and the amic acid part to the imide-amic acid copolymer is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more. , still more preferably 82% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and there is no upper limit. It is not more than 100% by mass.
• the total molar ratio of the imide part and the amic acid part to the imide-amic acid copolymer is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% or more. , still more preferably 82 mol% or more, even more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and there is no upper limit. It is not more than 100 mol%.
• the polyimide precursor may be produced by any method.
• the polyimide precursor is an imide-amic acid copolymer
• it is preferably obtained by a manufacturing method comprising the following steps a and b.
• Step a A step of reacting the tetracarboxylic dianhydride constituting the imide moiety with a diamine to obtain an imide oligomer.
• Step b Reacting the imide oligomer obtained in Step 1 with the tetracarboxylic dianhydride constituting the amic acid moiety.
• this production method it is possible to control the imide moiety and the amic acid moiety into a specific structure, which is different from the conventional imide-amic acid copolymer in which the imide moiety and the amic acid moiety are randomly present. It is considered that, depending on the thermal imidization reactivity of each component, it is possible to obtain an imide-amic acid copolymer that is expected to have improved heat resistance because it has a polyimide part and a polyamic acid part.
• the polyimide precursor is a polyamic acid
• it can be produced only by the step b (without using an imide oligomer). That is, it is preferable to obtain the imide-amic acid copolymer by a production method that includes a step of reacting the tetracarboxylic dianhydride and diamine constituting the amic acid moiety to obtain an imide-amic acid copolymer. Preferred conditions and the like are the same as in step b.
• Step a is a step of reacting the tetracarboxylic dianhydride constituting the imide portion with a diamine to obtain an imide oligomer.
• the molar ratio of diamine to tetracarboxylic dianhydride is preferably 1.01 to 2 mol, and preferably 1.05 to 1.9 mol. is more preferable, and even more preferably 1.1 to 1.7 mol.
• the specific reaction method is as follows: (1) Tetracarboxylic dianhydride, diamine, and reaction solvent are charged into a reactor, stirred at 10 to 110°C for 0.5 to 30 hours, and then heated to form an imide. (2) After charging the diamine and the reaction solvent into a reactor and dissolving them, charging the tetracarboxylic dianhydride and stirring at 10 to 110°C for 0.5 to 30 hours as necessary. (3) A method in which the tetracarboxylic dianhydride, diamine, and reaction solvent are charged into a reactor and the temperature is immediately raised to carry out the imidization reaction. .
• the imidization reaction it is preferable to use a Dean-Stark apparatus or the like to conduct the reaction while removing water generated during production. By performing such an operation, the degree of polymerization and the imidization rate can be further increased.
• imidization catalysts include base catalysts and acid catalysts.
• Base catalysts include pyridine, quinoline, isoquinoline, ⁇ -picoline, ⁇ -picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N
• organic base catalysts such as -dimethylaniline and N,N-diethylaniline
• inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogen carbonate, and sodium hydrogen carbonate.
• examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, etc. can be mentioned.
• the above imidization catalysts may be used alone or in combination of two or more.
• base catalysts are preferred, organic base catalysts are more preferred, one or more selected from triethylamine and triethylenediamine are still more preferred, and triethylamine is even more preferred.
• the temperature of the imidization reaction is preferably 120 to 250°C, more preferably 160 to 200°C from the viewpoint of reaction rate and suppression of gelation and the like. Further, the reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water.
• the imide oligomer obtained in step a preferably has amino groups at both ends of the main chain of the molecular chain.
• a solution containing an imide oligomer dissolved in a solvent is obtained.
• the solution containing the imide oligomer obtained in step a contains at least a portion of the components used as the tetracarboxylic dianhydride and diamine in step a as unreacted monomers to the extent that the effects of the present invention are not impaired. You can leave it there.
• the number average molecular weight (Mn) of the imide oligomer obtained in step a is preferably 1,000 to 100,000 from the viewpoint of heat resistance and mechanical strength of the obtained polyimide film. Further, from the same viewpoint, the weight average molecular weight (Mw) is preferably 1,000 to 100,000.
• the number average molecular weight or weight average molecular weight of the copolymer can be determined, for example, from a standard polymethyl methacrylate (PMMA) equivalent value measured by gel filtration chromatography or by a light scattering method.
• step b the imide oligomer obtained in step a is reacted with a tetracarboxylic dianhydride and a diamine constituting the amic acid moiety to form an imide-amic acid copolymer containing a repeating unit consisting of an imide moiety and an amic acid moiety.
• step b There is no particular restriction on the method of reacting the tetracarboxylic dianhydride and the imide oligomer obtained in step a to obtain the imide-amic acid copolymer in step b, and any known method can be used.
• any known method can be used.
• the imide oligomer obtained in step a, tetracarboxylic dianhydride, diamine, and solvent are charged into a reactor and heated at a temperature of 0 to 120°C, preferably 5 to 80°C.
• Method of stirring for 1 to 72 hours (2) After charging the imide oligomer obtained in step a and the solvent into a reactor and dissolving it, charging the tetracarboxylic dianhydride and diamine, and stirring at 0 to 120°C, preferably Examples include a method of stirring at a temperature of 5 to 80°C for 1 to 72 hours.
• the reaction is carried out at 80°C or lower, the molecular weight of the copolymer obtained in step b does not vary depending on the temperature history during polymerization, and the progress of thermal imidization can be suppressed. can be manufactured stably.
• a copolymer solution containing an imide-amic acid copolymer dissolved in a solvent is obtained. Further, by the above method that does not use an imide oligomer, a copolymer solution containing polyamic acid dissolved in a solvent can be obtained.
• the concentration of the polyimide precursor in the obtained polyimide precursor solution is preferably 1 to 50% by mass, more preferably 3 to 35% by mass, and still more preferably 5 to 30% by mass.
• the concentration of the copolymer in the resulting copolymer solution is preferably 1 to 50% by weight, more preferably 3 to 35% by weight, and even more preferably 5 to 30% by weight.
• the concentration of polyamic acid in the resulting polyamic acid solution is preferably 1 to 50% by weight, more preferably 3 to 35% by weight, and still more preferably 5 to 30% by weight.
• the number average molecular weight of the polyimide precursor is preferably 5,000 to 500,000 from the viewpoint of mechanical strength of the resulting polyimide film. Further, from the same viewpoint, the weight average molecular weight (Mw) of the polyimide precursor is preferably 10,000 to 800,000, more preferably 10,000 to 300,000, and still more preferably 100,000. ⁇ 300,000. The number average molecular weight of the polyimide precursor can be determined, for example, from a standard polymethyl methacrylate (PMMA) value measured by gel filtration chromatography.
• PMMA polymethyl methacrylate
• the tetracarboxylic dianhydride and diamine that are the raw materials used in the method for producing the polyimide precursor, it is preferable to use a compound that provides each of the structural units described in the above-mentioned structural units of the polyimide precursor, and the suitable range is also limited.
• the tetracarboxylic dianhydride includes acid dianhydride, but is not limited thereto, and derivatives thereof may be used as long as they provide the same structural unit.
• the derivatives include tetracarboxylic acids and alkyl esters of the tetracarboxylic acids, and among these, acid dianhydrides are preferred.
• diamines include diamines, but are not limited thereto, and derivatives thereof may be used as long as they provide the same structural unit. Examples of such derivatives include diisocyanates corresponding to diamines, and among these, diamines are preferred.
• An end capping agent may be used in the production of the polyimide precursor.
• the terminal capping agent is preferably used in step b.
• monoamines or dicarboxylic acids are preferable.
• the amount of the terminal capping agent to be introduced is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, per 1 mol of tetracarboxylic dianhydride.
• Examples of monoamine terminal capping agents include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3- Examples include ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like. Among these, benzylamine and aniline are preferred.
• dicarboxylic acid terminal capping agent dicarboxylic acids are preferable, and some of them may be ring-closed.
• phthalic acid for example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1 , 2-dicarboxylic acid and the like.
• phthalic acid and phthalic anhydride are preferred.
• a solvent may be used as the reaction solvent.
• the solvent may be any solvent as long as it can dissolve the polyimide precursor to be produced. Examples include aprotic solvents, phenolic solvents, ether solvents, carbonate solvents, etc. Suitable solvents are the same as those used for varnishes described below.
• the varnish used in step 1 contains the polyimide precursor and a solvent.
• the solvent may be any solvent as long as it can dissolve the polyimide precursor. Examples include aprotic solvents, phenolic solvents, ether solvents, carbonate solvents, and the like.
• aprotic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, and tetramethylurea.
• amide solvents lactone solvents such as ⁇ -butyrolactone and ⁇ -valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide, sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide, and sulfolane.
• Examples include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl cyclohexanone, and ester solvents such as acetic acid (2-methoxy-1-methylethyl).
• ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl cyclohexanone
• ester solvents such as acetic acid (2-methoxy-1-methylethyl).
• phenolic solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4 -xylenol, 3,5-xylenol, etc.
• ether solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, and bis[2-(2-methoxyethoxy)ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane and the like.
• carbonate solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, and the like.
• amide solvents or lactone solvents are preferred, amide solvents are more preferred, and N-methyl-2-pyrrolidone is even more preferred.
• the above solvents may be used alone or in combination of two or more.
• the varnish may be the above-mentioned polyimide precursor solution itself, or may be the polyimide precursor solution to which a diluting solvent is further added.
• the varnish may be the above-mentioned copolymer solution itself, or may be the copolymer solution to which a diluting solvent is further added.
• the varnish may be the above-mentioned polyamic acid solution itself, or may be the polyamic acid solution to which a diluting solvent is further added.
• the varnish of the present invention can further contain an imidization catalyst and a dehydration catalyst from the viewpoint of efficiently progressing the imidization of the amic acid moiety of the polyimide precursor.
• an imidization catalyst any imidization catalyst with a boiling point of 40°C or higher is sufficient. If the imidization catalyst has a boiling point of 40°C or higher, it is possible to avoid the possibility of volatilization before imidization progresses sufficiently.
• the imidization catalyst include amine compounds such as pyridine or picoline; imidazole compounds such as imidazole, 1,2-dimethylimidazole, 1-benzylimidazole, 1-benzyl-2-methylimidazole, and benzimidazole; and the like.
• the above imidization catalysts may be used alone or in combination of two or more.
• the dehydration catalyst include acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride; and carbodiimide compounds such as dicyclohexylcarbodiimide. These may be used alone or in combination of two or more.
• acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride
• carbodiimide compounds such as dicyclohexylcarbodiimide.
• the varnish preferably contains 3 to 40% by mass of the polyimide precursor, more preferably 5 to 40% by mass, and even more preferably 6 to 30% by mass.
• the viscosity of the varnish is preferably 0.1 to 100 Pa ⁇ s, more preferably 0.1 to 20 Pa ⁇ s.
• the viscosity of the varnish is a value measured at 25°C using an E-type viscometer.
• the varnish may contain inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, surfactants, leveling agents, antifoaming agents, optical brighteners, etc., as long as they do not impair the required properties of the polyimide film. It may also contain various additives such as a crosslinking agent, a polymerization initiator, and a photosensitizer.
• the method for producing the varnish is not particularly limited, and any known method can be applied.
• Step 1 is a step of removing the solvent from a varnish containing a polyimide precursor having a polyamic acid moiety and a solvent at 50 to 120° C. and drying the varnish.
• step 1 the polyimide varnish is applied onto the substrate after the solvent is removed from the varnish and the polyimide varnish is dried.
• the coating method a known method can be used. For example, slit coating or spin coating can be used.
• the base material include smooth plate-shaped objects such as glass plates, metal plates, and plastic plates.
• “Applying varnish onto a base material” refers to pouring varnish onto a base material and forming it into a film.
• the temperature during drying is 50 to 120°C, preferably 60 to 120°C, more preferably 70 to 120°C, and still more preferably 80 to 120°C.
• the drying time is preferably 10 to 60 minutes, more preferably 10 to 50 minutes, and even more preferably 10 to 40 minutes.
• the temperature range to be maintained may vary, but the range of variation is preferably narrow.
• the range of temperature change during drying is preferably 30°C or less, more preferably 20°C or less, still more preferably 10°C or less, even more preferably 5°C or less. Even more preferably, there is no substantially varying range.
• the polyimide film can be formed into the desired shape by drying it on the base material.
• Step 2 The method for producing a polyimide film of the present invention includes a step 1 and a step 2.
• Step 2 is a step of imidizing by holding at 300 to 400°C for 10 to 120 minutes and then holding at 420 to 500°C.
• Step 2 uses the polyimide precursor formed into a film shape obtained in Step 1.
• step 2 by holding the polyimide precursor at the two temperatures mentioned above, the imidization reaction and polymerization of the polyimide precursor can be fully achieved, resulting in high colorless transparency and high elongation.
• a polyimide film which is further excellent in heat resistance can be obtained. The reason is not clear, but it is thought to be as follows. It is believed that if the polyimide precursor is heated rapidly without sufficient thermal imidization and molecular weight increase, thermal deterioration will occur, and the molecular weight will no longer increase or the structure will change to cause coloration. It will be done.
• the imidization reaction and polymerization are achieved before thermal deterioration, and the resulting polyimide film has a high It is believed to be colorless and transparent, has a high elongation rate, and also has excellent heat resistance.
• step 2 from the viewpoint of promoting the imidization reaction, the polyimide precursor is held at two temperatures: held at at least 300 to 400°C for 10 to 120 minutes, and then held at 420 to 500°C. Further, in step 2, a preheating step may be provided before holding at the two temperatures described above, and it is preferable to provide a preheating step.
• the temperature is preferably maintained at one or more stages, and more preferably at two or more stages. Further, it is preferable to maintain the temperature at three or less levels. It is further preferable that the preheating step be maintained at two temperatures. By providing a preheating step, it is possible to further suppress a decrease in colorless transparency and elongation rate.
• the preheating step is a step of holding at two temperatures
• the temperature in the first step is preferably 100 to 180°C, more preferably 120 to 150°C.
• the holding time in the first stage is preferably 10 to 120 minutes, more preferably 20 to 60 minutes.
• the temperature in the second stage is 180 to 300°C, more preferably 200 to 250°C.
• the holding time in the second stage is preferably 10 to 120 minutes, more preferably 20 to 60 minutes.
• the temperature range to be maintained may vary, but the range of variation is preferably narrow.
• the range of temperature change during drying is preferably 30°C or less, more preferably 20°C or less, still more preferably 10°C or less, even more preferably 5°C or less. Even more preferably, there is no substantially varying range.
• the method of raising the temperature from the drying temperature in step 1 to the holding temperature in the preheating step in step 2 is not particularly limited, but it is possible to shorten the time required to produce the polyimide film without impairing the effects of the present invention. Therefore, the rate of temperature increase from the drying temperature in step 1 to the holding temperature in the preheating step of step 2 is preferably 1 to 10 ° C./min, more preferably 2 to 9 ° C./min, More preferably, it is 3 to 8°C/min.
• the atmosphere in the preheating step can be air gas, nitrogen gas, oxygen gas, hydrogen gas, nitrogen/hydrogen mixed gas, etc., but in order to suppress the coloring of the obtained polyimide film, nitrogen with an oxygen concentration of 100 ppm or less is used.
• nitrogen/hydrogen mixed gas containing hydrogen at a hydrogen concentration of 0.5% or less is preferred.
• the polyimide precursor is held at two temperatures: held at at least 300 to 400°C for 10 to 120 minutes, and then held at 420 to 500°C.
• the temperature in the first stage is 300 to 400°C, preferably 340 to 390°C.
• the holding time in the first stage is 10 to 120 minutes, preferably 15 to 60 minutes. It is thought that by holding the temperature at 300 to 400°C, the imidization reaction and increase in molecular weight can be achieved without thermal deterioration, and the resulting polyimide film has high colorless transparency and high elongation, and is heat resistant. It also has excellent sex.
• the temperature in the second stage is 420 to 500°C, more preferably 430 to 470°C.
• the holding time in the second stage is not limited and may be held until imidization is completed, but is preferably 10 to 120 minutes, more preferably 10 to 60 minutes.
• the temperature range to be maintained may vary, but the range of variation is preferably narrow.
• the range of temperature change during drying is preferably 30°C or less, more preferably 20°C or less, still more preferably 10°C or less, even more preferably 5°C or less. Even more preferably, there is no substantially varying range.
• the method of raising the temperature from the holding temperature in the preheating step to the holding temperature in the first stage of step 2 is not particularly limited, but from the viewpoint of shortening the time required to produce the polyimide film without impairing the effects of the present invention,
• the temperature increase rate from the holding temperature in the preheating step to the holding temperature in the first stage of step 2 is preferably 1 to 10°C/min, more preferably 2 to 9°C/min, and even more preferably 3°C/min. ⁇ 8°C/min. Even if Step 2 does not include a preheating step, the method of raising the temperature from the drying temperature in Step 1 to the holding temperature in the first stage of Step 2 is not particularly limited, but the method may not impair the effects of the present invention.
• the temperature increase rate from the drying temperature in step 1 to the holding temperature in the first stage of step 2 is preferably 1 to 10 ° C./min, More preferably 2 to 9°C/min, still more preferably 3 to 8°C/min.
• the atmosphere in step 2 includes air gas, nitrogen gas, oxygen gas, hydrogen gas, nitrogen/hydrogen mixed gas, etc., but in order to suppress the coloring of the obtained polyimide film, nitrogen gas with an oxygen concentration of 100 ppm or less is used. , a nitrogen/hydrogen mixed gas containing hydrogen at a hydrogen concentration of 0.5% or less is preferred.
• the polyimide film of the present invention is a polyimide film obtained by the above manufacturing method.
• the thickness of the polyimide film of the present invention can be appropriately selected depending on the intended use, but is preferably 1 to 250 ⁇ m, more preferably 5 to 100 ⁇ m, and still more preferably 5 to 50 ⁇ m.
• the thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and viscosity of the varnish.
• the polyimide film of the present invention has high colorless transparency and high elongation, but the preferred physical properties of the polyimide film of the present invention are as follows.
• the yellow index of the polyimide film when the thickness is 10 ⁇ m is preferably 30 or less, more preferably less than 30, still more preferably 28 or less, even more preferably 25 or less.
• the tensile elongation rate when a polyimide film with a thickness of 10 ⁇ m is subjected to a tensile test with a test piece size of 10 mm x 70 mm and a distance between chucks of 50 mm is preferably 10% or more, more preferably 11% or more, and Preferably it is 12% or more.
• the weight loss rate at 300 to 400°C which is measured by raising the temperature from 40°C to 550°C at a heating rate of 10°C/min using a differential thermogravimetric simultaneous measuring device, is preferably 0.3% or less. It is more preferably 0.2% or less, still more preferably 0.1% or less.
• the above-mentioned physical property values in the present invention can be specifically measured by the method described in the Examples.
• the polyimide film of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members.
• the polyimide film of the present invention is particularly suitably used as a substrate for image display devices such as liquid crystal displays and OLED displays.
• the polyimide film obtained by the production method of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members.
• the polyimide film obtained by the production method of the present invention is particularly suitably used as a substrate for image display devices such as liquid crystal displays and OLED displays.
• tetracarboxylic dianhydride and diamine used in Examples and Comparative Examples, and their abbreviations are as follows.
• BPAF 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (compound represented by formula (a2), Ea: 1.94 eV, manufactured by JFE Chemical Corporation)
• SFDA spiro[11H-difuro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7,9-tetron (formula (a3) Represented compound, Ea: 2.08eV, manufactured by Air Water Performance Chemical Co., Ltd.)
• solvents and catalysts used in Examples and Comparative Examples are as follows.
• NMP N-methyl-2-pyrrolidone (manufactured by Tokyo Pure Chemical Industries, Ltd.)
• TEA Triethylamine (manufactured by Kanto Kagaku Co., Ltd.)
• Example 1 32.765 g (0.144 mol) of 4-BAAB was placed in a 500 mL 5-necked round-bottomed flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap. ) and 180.000 g of NMP were added, the system temperature was set to 50° C. under a nitrogen atmosphere, and the mixture was stirred to obtain a solution. To this solution, 42.235 g (0.144 mol) of s-BPDA and 120.000 g of NMP were added all at once, and the mixture was stirred at 50° C. for 5 hours.
• Step 1 NMP was added and homogenized so that the solid content concentration was about 15% by mass, thereby obtaining a varnish containing polyamic acid.
• the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1).
• the mixture was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in a hot air dryer under a nitrogen atmosphere to obtain a polyimide film (Step 2).
• Table 1 shows the physical properties and evaluation results of the film.
• Example 2 9.370 g (0.041 mol) of 4-BAAB was placed in a 500 mL 5-necked round-bottomed flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap. ) and 207.059 g of NMP were added, the system temperature was set to 70° C. under a nitrogen atmosphere, and the mixture was stirred to obtain a solution. After adding 12.546 g (0.027 mol) of BPAF and 40.000 g of NMP in one batch to this solution, 0.138 g of TEA as an imidization catalyst and 5.000 g of NMP were added, and heated with a mantle heater.
• the temperature inside the reaction system was raised to 180°C over about 20 minutes. While collecting the components to be distilled off, the temperature inside the reaction system was maintained at 180°C and refluxed for 2 hours. Thereafter, the temperature inside the reaction system was cooled to 50° C. to obtain a solution containing an oligomer having an imide repeating structural unit. To the resulting solution, 32.250 g (0.110 mol) of s-BPDA, 21.863 g (0.096 mol) of 4-BAAB, and 47.940 g of NMP were added all at once, and the mixture was stirred at 80° C. for 3 hours.
• Example 3 12.516 g (0.039 mol) of TFMB and 97.348 g of NMP was added, the system temperature was set to 70° C. under a nitrogen atmosphere, and the mixture was stirred to obtain a solution. After adding 11.944 g (0.026 mol) of BPAF and 30.000 g of NMP in one batch to this solution, 0.132 g of TEA as an imidization catalyst and 5.000 g of NMP were added, and heated with a mantle heater. The temperature inside the reaction system was raised to 190°C over about 20 minutes. While collecting the components to be distilled off, the temperature inside the reaction system was maintained at 190°C and refluxed for 1 hour.
• the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2).
• Table 1 shows the physical properties and evaluation results of the film.
• Example 4 A varnish was obtained in the same manner as in Example 2. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the polyimide film was held at 120°C for 30 minutes, 200°C for 15 minutes (preheating step in step 2), 350°C for 15 minutes, and 450°C for 10 minutes. was obtained (Step 2). Table 1 shows the physical properties and evaluation results of the film.
• Example 5 A varnish was obtained in the same manner as in Example 2. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the polyimide film was heated to 150°C for 30 minutes, 200°C for 15 minutes (preheating step of step 2), 350°C for 15 minutes, and 450°C for 10 minutes. was obtained (Step 2). Table 1 shows the physical properties and evaluation results of the film.
• Example 6 A varnish was obtained in the same manner as in Example 2. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 120° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the polyimide film was heated to 150°C for 30 minutes, 200°C for 15 minutes (preheating step of step 2), 350°C for 15 minutes, and 450°C for 10 minutes. was obtained (Step 2). Table 1 shows the physical properties and evaluation results of the film.
• Example 7 9.322 g (0.041 mol) of 4-BAAB was placed in a 500 mL 5-necked round-bottomed flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap. ) and 220.131 g of NMP were added, the system temperature was set to 70° C. under a nitrogen atmosphere, and the mixture was stirred to obtain a solution. After adding 12.863 g (0.027 mol) of SFDA and 30.000 g of NMP in one batch to this solution, 0.138 g of TEA as an imidization catalyst and 5.000 g of NMP were added, and heated with a mantle heater.
• the temperature inside the reaction system was raised to 190°C over about 20 minutes. While collecting the components to be distilled off, the temperature inside the reaction system was maintained at 190°C and refluxed for 1 hour. Thereafter, 29.861 g of NMP was added and the temperature inside the reaction system was cooled to 50° C. to obtain a solution containing an oligomer having an imide repeating structural unit. To the resulting solution, 32.044 g (0.109 mol) of s-BPDA, 21.752 g (0.095 mol) of 4-BAAB, and 15.000 g of NMP were added all at once, and the mixture was stirred at 70° C. for 5 hours.
• Step 1 NMP is added and homogenized so that the solid content concentration is approximately 15% by mass, thereby producing a copolymer having imide repeating structural units and amic acid repeating structural units (imide-amic acid copolymer). Obtained a varnish containing. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the polyimide film was heated to 150°C for 30 minutes, 200°C for 15 minutes (preheating step of step 2), 350°C for 15 minutes, and 450°C for 10 minutes. was obtained (Step 2). Table 1 shows the physical properties and evaluation results of the film.
• Example 8 ABHQ 11.731 g (0.034 mol) and 218.217 g of NMP was added, the system temperature was set to 70° C. under a nitrogen atmosphere, and the mixture was stirred to obtain a solution. After adding 10.290 g (0.022 mol) of BPAF and 30.000 g of NMP in one batch to this solution, 0.114 g of TEA as an imidization catalyst and 5.000 g of NMP were added, and heated with a mantle heater. The temperature inside the reaction system was raised to 190°C over about 20 minutes. While collecting the components to be distilled off, the temperature inside the reaction system was maintained at 190°C and refluxed for 1 hour.
• the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the polyimide film was heated to 150°C for 30 minutes, 200°C for 15 minutes (preheating step of step 2), 350°C for 15 minutes, and 450°C for 10 minutes. was obtained (Step 2).
• Table 1 shows the physical properties and evaluation results of the film.
• Example 9 31.074 g (0.136 mol) of 4-BAAB was placed in a 500 mL five-necked round-bottomed flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. ) and 243.140 g of NMP were added, the system temperature was set to 50° C. under a nitrogen atmosphere, and the mixture was stirred at a rotational speed of 200 rpm to obtain a solution.
• Example 10 31.233 g (0.137 mol) of 4-BAAB was placed in a 500 mL 5-necked round-bottomed flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap. ) and 243.156 g of NMP were added, the system temperature was set to 50° C. under a nitrogen atmosphere, and the mixture was stirred at a rotational speed of 200 rpm to obtain a solution.
• Comparative example 1 A varnish was obtained in the same manner as in Example 1. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, it was held at 450° C. for 10 minutes in a hot air dryer under a nitrogen atmosphere to obtain a polyimide film. Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 2 A varnish was obtained in the same manner as in Example 2. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, it was held at 450° C. for 10 minutes in a hot air dryer under a nitrogen atmosphere to obtain a polyimide film. Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 3 A varnish was obtained in the same manner as in Example 2. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, the temperature was held at 250° C. for 15 minutes and at 450° C. for 10 minutes in stages in a hot air dryer under a nitrogen atmosphere to obtain a polyimide film. Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 4 A varnish was obtained in the same manner as in Example 3. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, it was held at 450° C. for 10 minutes in a hot air dryer under a nitrogen atmosphere to obtain a polyimide film. Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 6 A varnish was obtained in the same manner as in Comparative Example 5. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2). Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 7 A varnish was obtained in the same manner as in Example 7. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2). Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 8 A varnish was obtained in the same manner as in Example 8. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2). Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 9 A varnish was obtained in the same manner as in Example 9. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2). Table 2 shows the physical properties and evaluation results of the film.
• Comparative example 10 A varnish was obtained in the same manner as in Example 10. Subsequently, the obtained varnish was applied onto a glass plate by spin coating and held at 80° C. for 20 minutes on a hot plate (Step 1). Thereafter, in a hot air dryer under a nitrogen atmosphere, the temperature was held at 350° C. for 15 minutes and at 450° C. for 10 minutes in stages to obtain a polyimide film (Step 2). Table 2 shows the physical properties and evaluation results of the film.
• the polyimide film obtained by the production method of the example showed little weight loss from 300°C to 400°C, indicating that the imidization reaction and the increase in molecular weight were sufficiently achieved. Moreover, it can be seen that the polyimide film obtained by the manufacturing method of the example can achieve both a low yellow index and a high tensile elongation rate. From the above, the method for producing a polyimide film of the present invention can sufficiently achieve the imidization reaction and increase in molecular weight of the polyimide precursor, has high colorless transparency and high elongation rate, and has high heat resistance. It can be seen that a polyimide film with excellent properties can be obtained.

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• 2023
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