KR20230163300A - Novel diamine compounds, polyamic acid and polyimide formed therefrom - Google Patents

Abstract

A diamine compound represented by the following formula (1) is provided. Additionally, a polyamic acid containing a structural unit derived from a diamine compound is provided. Also provided are polyimides and polyimide films formed from polyamic acids. The heat resistance, optical properties, and flexibility of the polyimide film can be improved.
[Formula 1]

Description

Novel diamine compound, polyamic acid and polyimide formed therefrom {NOVEL DIAMINE COMPOUNDS, POLYAMIC ACID AND POLYIMIDE FORMED THEREFROM}

The present invention relates to novel diamine compounds, polyamic acids and polyimides formed therefrom.

Polyimide is easy to synthesize and can be cured without a crosslinker, and a thin film can be provided from polyimide. Recently, as electronic products have become lighter, more integrated, and more precise, polyimide is being applied as an integration material for semiconductor materials such as liquid crystal displays (LCDs) and plasma display panels (PDPs). For example, research is underway to use polyimide in a flexible plastic display board that is lightweight and flexible.

Polyimide film can be manufactured by turning polyimide polymer into a film. For example, a polyimide film can be prepared by solution polymerizing aromatic dianhydride and aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative solution, which is then coated on a silicon wafer or glass and heat treated. You can.

Polyimide polymer can be manufactured by dissolving it in an organic solvent with a high boiling point, applying it to a substrate in the form of polyamic acid, which is a precursor, and then heat-treating it at a temperature of 300°C or higher for a long time to dehydrate/imidize it.

However, since the dehydration and imidization reaction of the polyamic acid is heated at a high temperature for a long time, the quality of the polyimide may deteriorate. In addition, if heating is insufficient, polyamic acid may remain in the structure of the produced polyimide polymer, thereby reducing moisture resistance, corrosion resistance, etc.

Japanese Patent Publication No. 1990-036232 proposes a method of producing a polyimide polymer film by applying a polyimide polymer solution soluble in an organic solvent to a substrate and then heating it to volatilize the solvent. However, the polyimide polymer coating produced by the above-described method may have low solvent resistance.

Japanese Patent Publication No. 1998-195278 proposes a thermosetting polyimide polymer composition for producing a polyimide polymer film by heat treatment at a low temperature for a short time. However, the thermosetting resin does not exhibit sufficient heat resistance or has low transparency, so its field of use is limited.

Japanese Patent Publication No. 1990-036232 Japanese Patent Publication No. 1998-195278

One object of the present invention is to provide a novel diamine compound.

One object of the present invention is to provide a polyamic acid formed from the above-described diamine compound.

One object of the present invention is to provide a polyimide formed from the above-described polyamic acid.

One object of the present invention is to provide a method for producing a novel diamine compound.

One object of the present invention is to provide a method for producing polyimide.

Diamine compounds according to embodiments of the present invention may be represented by the following formula (1).

[Formula 1]

In Formula 1, X may be a single bond (direct linkage) or a divalent organic group.

R ¹ and R ² may each independently be a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-).

In one embodiment, in Formula 1, R ¹ and R ² are each independently -R ³ -R ⁴ -, and R ³ and R ⁴ are each independently a C1 to C5 alkylene group or C1 to C5 oxyalkyl. It could be Rengi.

According to exemplary embodiments, the diamine compound may include at least one of the compounds represented by Formulas 4 to 15 below.

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

Polyamic acid polymers according to embodiments of the present invention may include structural units derived from the diamine compounds.

In some embodiments, the polyamic acid polymer may include a polymer of the diamine compound and the aromatic tetracarboxylic dianhydride compound.

In some embodiments, the polyamide polymer may include a repeating unit represented by Formula 2 below.

[Formula 2]

In Formula 2, X may be a single bond, a C1 to C4 alkylene group, -O-, -C(=O)-, -SO ₂ -, or -C(R ⁵ )(R ⁶ )-. R ⁵ and R ⁶ may each independently be hydrogen, a C1 to C4 alkyl group, or a C1 to C4 alkyl group in which at least one hydrogen is substituted with fluorine. R ⁵ and R ⁶ may be connected to each other to form a ring.

R ¹ and R ² may each independently be a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-).

Ar may be a C6 to C40 divalent aromatic hydrocarbon group.

n may be an integer from 10 to 1000.

Polyimide according to embodiments of the present invention may include an imidization reaction product of the polyamic acid polymer.

In some embodiments, the polyimide may include a repeating unit represented by Formula 3 below.

[Formula 3]

In Formula 3, X may be a single bond, a C1 to C4 alkylene group, -O-, -C(=O)-, -SO ₂ - or -C(R ⁵ )(R ⁶ )-. R ⁵ and R ⁶ may each independently be hydrogen, a C1 to C4 alkyl group, or a C1 to C4 alkyl group in which at least one hydrogen is substituted with fluorine. R ⁵ and R ⁶ may be connected to each other to form a ring.

R ¹ and R ² may each independently be a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-).

Ar may be a C6 to C40 divalent aromatic hydrocarbon group.

n may be an integer from 10 to 1000.

Polyimide films according to embodiments of the present invention may include the polyimide.

Flexible devices according to embodiments of the present invention may include the polyimide film.

According to embodiments of the present invention, a compound represented by Formula 16 is reacted with a compound represented by Formula 17 to prepare a compound represented by Formula 18, and the compound represented by Formula 18 is reduced to obtain Formula 18. A diamine compound represented by 1 can be produced.

[Formula 16]

[Formula 17]

[Formula 18]

In Formulas ¹⁶ to 18 ^, It is a C10 alkylene group, and R ¹ and R ² may be an organic group derived from R.

According to embodiments of the present invention, polyimide can be produced by reacting the diamine compound represented by Formula 1 and the tetracarboxylic dianhydride compound at a temperature of 300°C or lower.

In some embodiments, the tetracarboxylic acid dianhydride compound may be an aromatic tetracarboxylic dianhydride compound.

In some embodiments, the polyamine compound and the tetracarboxylic dianhydride may be reacted at a temperature of 150°C to 300°C for 1 to 15 hours.

In some embodiments, the step of reacting the diamine compound and the tetracarboxylic dianhydride compound includes a first heat treatment step of reacting at a temperature of 0°C to 120°C for 1 to 100 hours, and a temperature of 0°C to 300°C. It may include a second heat treatment step performed at a temperature for 1 to 15 hours.

In one embodiment, polyamic acid may be formed from the polyamine compound and the tetracarboxylic dianhydride through the first heat treatment step, and polyimide may be formed from the polyamic acid through the second heat treatment step.

According to embodiments of the present invention, the polyimide polymer may include structural units derived from novel diamine compounds. The heat resistance and optical properties of polyimide polymer can be improved by the structural unit derived from the diamine compound.

Additionally, the polyimide polymer formed using the diamine compound may have high solubility in organic solvents. Therefore, the moldability and processability of the polyimide film can be improved.

Polyimide film has improved optical properties, dielectric constant, and heat resistance, and is used in, for example, color filters for semiconductor devices, light emitting diodes, protective films for laser diodes, liquid crystal alignment films, liquid crystal displays, flexible substrates for optical devices, electronics, and optics. It can be usefully applied, etc.

Figure 1 is an NMR analysis spectrum of a diamine compound according to Example 1.
Figure 2 is an NMR analysis spectrum of a diamine compound according to Example 2.
Figure 3 is an NMR analysis spectrum of a diamine compound according to Example 3.

According to embodiments of the present invention, novel diamine compounds can be provided. In addition, polyamic acid polymers prepared from novel diamine compounds, polyimides and polyimide films prepared from the polyamic acid polymers can be provided.

Below, embodiments of the present invention will be described in detail.

When there are isomers of a compound represented by a chemical formula used in this specification, the compound represented by the chemical formula means a representative chemical formula including the isomers.

As used herein, the term “X-based compound” may mean an X compound or a derivative of an X compound. “X compound” may refer to a compound containing X units as a parent, side group, or substituent.

As used herein, the term “Ca to Cb” may mean “the number of carbon atoms from a to b.”

<Diamine compound>

Diamine compounds according to exemplary embodiments may be represented by Formula 1 below.

[Formula 1]

In Formula 1, X may be a single bond (direct linkage) or a divalent organic group. A single bond may mean that X and the carbon atoms of the adjacent benzene ring are directly connected.

In one embodiment, the divalent organic group may be a C1 to C4 alkylene group, -O-, -C(=O)-, -SO ₂ -, or -C(R ⁵ )(R ⁶ )-. R ⁵ and R ⁶ may each independently be hydrogen or a C1 to C4 alkyl group.

In one embodiment, R ⁵ and R ⁶ may each independently be a C1 to C4 alkyl group in which at least one hydrogen is replaced with a halogen atom (eg, F, Cl, Br or I). For example, R ⁵ and R ⁶ may be a C1 to C4 fluorinated alkyl group.

In some embodiments, R ⁵ and R ⁶ may be connected to each other to form a ring. For example, R ⁵ and R ⁶ may be combined with each other to form a C3 to C8 hydrocarbon ring.

R ¹ and R ² may each independently be a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-).

For example, in Formula 1, R ¹ and R ² are each independently *-R ³ -R ⁴ -*, and R ³ and R ⁴ are each independently a C1 to C5 alkylene group or C1 to C5 oxyalkyl. It could be Rengi. * is a bond with an adjacent oxygen atom.

The term “alkylene group” used herein refers to a divalent hydrocarbon group in which two hydrogen atoms are removed from a straight-chain or branched-chain saturated hydrocarbon. For example, as an alkylene group, methylene group, ethylene group, i-propylene group, n-propylene group, t-butylene group, s-butylene group, n-butylene group, pentylene group, dimethylpropylene group, ethylpropylene group, A methyl ethyl propylene group, a hexylene group, etc. are mentioned.

The term “oxyalkylene group” used herein refers to a functional group in which one of the carbon atoms of a divalent hydrocarbon group is replaced with an oxygen atom. For example, an oxymethylene group may have a structure in which one of the carbon atoms of the ethylene group is replaced with an oxygen atom. Examples of oxyalkylene groups include oxymethylene group, oxyethylene group, oxypropylene group, oxybutylene group, oxypentylene group, dimethyloxypropylene group, and ethyloxypropylene group.

In Formula 1, the benzene rings are connected to a highly electronegative substituent or polar functional group, so that π electron movement between adjacent aromatic structures may be limited, and charge transfer complex (CTC) due to π electrons may be reduced. . Additionally, as bulky substituents or functional groups exist within the molecule, the movement of the molecule may be inhibited and the glass transition temperature may increase.

According to exemplary embodiments, the diamine compound may include at least one of the compounds represented by Formulas 4 to 15 below.

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

In one example, a dinitro compound represented by Formula 18 can be synthesized by reacting an acid chloride compound represented by Formula 16 below and an amino alcohol compound represented by Formula 17 below. The diamine compound represented by Formula 1 can be prepared by reducing the dinitro compound.

[Formula 16]

[Formula 17]

[Formula 18]

In Formulas 16 to 18, X is a single bond or a divalent organic group, as described in Formula 1 above. R may be a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-). R ¹ and R ² may each be an organic group derived from R.

For example, the polyamine compound can be prepared by the method illustrated in Scheme 1 below.

<Scheme 1>

In some embodiments, a first precursor solution may be prepared by dissolving the acid chloride compound in an organic solvent. Additionally, a second precursor solution can be prepared by dissolving the amino alcohol compound in an organic solvent.

The second precursor solution may be added dropwise to the first precursor solution at a constant rate. Afterwards, the first precursor solution and the second precursor solution may be stirred and mixed to react the acid chloride compound and the amino alcohol compound.

A precipitate may be obtained by slowly adding the reaction mixture of the first precursor solution and the second precursor solution dropwise to water. Afterwards, the precipitate can be filtered and dried to obtain the dinitro compound.

The diamine compound represented by Formula 1 can be prepared by performing a reduction reaction of the dinitro compound. In one embodiment, the reduction reaction can be performed by dissolving the dinitro compound in an organic solvent and then adding a catalyst. For example, a palladium catalyst can be used as the catalyst.

<Polyamic acid>

Polyamic acid polymers according to exemplary embodiments may be prepared from the diamine compound represented by Formula 1 above.

The polyamic acid polymer may include structural units derived from the diamine compound. The thermal stability of the polymer is improved by the structural unit derived from the diamine compound, and the light transmittance in the visible light region can be improved.

For example, the polyamic acid polymer may include a structural unit represented by the following formula 2-1.

[Formula 2-1]

In Formula 2-1, X, R ¹ and R ² may be as described in Formula 1 above.

According to exemplary embodiments, the polyamic acid polymer may include a polymer of the diamine compound and tetracarboxylic dianhydride.

As the tetracarboxylic dianhydride, a non-colored compound or a compound that is difficult to form a charge transfer complex (CTC), which is known to cause coloring, can be used.

In one embodiment, aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride may be used as the tetracarboxylic dianhydride. In this case, the transparency of the polyimide polymer can be improved.

Examples of the aliphatic tetracarboxylic dianhydride include butane-1,2,3,4-tetracarboxylic dianhydride or pentane-1,2,4,5-tetracarboxylic dianhydride. Examples of alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, and dicyclohexyl-1,2,4,5-tetracarboxylic dianhydride. 3,4,3',4'-tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, 2,3,4,5-tetra Hydrofuran tetracarboxylic dianhydride, etc. can be mentioned.

According to exemplary embodiments, aromatic tetracarboxylic dianhydride may be used as tetracarboxylic dianhydride. By using a compound with an aromatic structure as a monomer, the heat resistance of the polymer can be improved, and mechanical properties can be improved due to the rigid aromatic structure.

In some embodiments, the aromatic tetracarboxylic dianhydride may include a compound represented by Formula 19 below.

<Formula 19>

In Formula 19, Ar may be a C6 to C40 divalent aromatic hydrocarbon group. An aromatic hydrocarbon group may refer to an organic group containing a benzene ring. For example, Ar may be a C6 to C40 aryl group, a C6 to C40 arylalkyl group, or a C6 to C40 heteroaryl group.

In one embodiment, Ar may be a C5 to C20 aromatic hydrocarbon group. By appropriately adjusting the number of carbon atoms in the aromatic ring, solubility in solvents can be improved and film production can become easier.

When Ar is a multicyclic hydrocarbon group containing two or more benzene rings, the benzene rings are single bonds, alkylene groups, -O-, C(=O)-, -S(=O)-, -SO ₂ -, - It may be connected to C(R ⁷ )(R ⁸ )-, -O-, or -S-, or may have a condensed polycyclic structure. R ⁷ and R ⁸ may each independently be a C1 to C4 alkyl group or a C1 to C4 alkyl group in which at least one hydrogen is substituted with fluorine.

In some embodiments, the aromatic tetracarboxylic dianhydride includes pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'- Examples include diphenyl ether tetracarboxylic dianhydride, 4,4'-hexafluoropropylidene bisphthalic dianhydride, and 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride.

In addition, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3 -Dione,1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c] An aliphatic tetracarboxylic dianhydride having an aromatic ring such as furan-1,3-dione can also be used.

In one embodiment, tetracarboxylic dianhydride can be used alone or in combination of two or more types.

In some embodiments, the diamine compound may further include one or more additional diamine compounds in addition to the compound represented by Formula 1. For example, the additional diamine compound may comprise a monocyclic or polycyclic C6 to C24 aromatic structure, a monocyclic or monocyclic C6 to C18 alicyclic structure, or a structure in which two or more of these are linked by a single bond or functional group. . Alternatively, a diamine compound containing a single or fused heterocyclic ring structure such as aromatic or alicyclic ring structure, or a structure in which two or more of these are connected by a single bond can be used.

In some embodiments, the polyamide polymer may include a repeating unit represented by Formula 2 below.

[Formula 2]

In Formula 2, X, R ¹ and R ² may be as described in Formula 1 above. Ar may be as described in Formula 19 above.

n may be an integer from 10 to 1000.

In some embodiments, the content of the repeating unit represented by Formula 2 may be 80 mol% or more, 90 mol% or more, or 95 mol% or more out of 100 mol% of the total repeating units of the polyamic acid polymer. Accordingly, the heat resistance and mechanical properties of the polymer can be improved, and light absorption due to the aromatic structure can be suppressed, thereby improving transmittance in the visible light region.

In one embodiment, the polyamic acid polymer may be composed of a repeating unit represented by Formula 2. For example, 10 to 1000 or 20 to 200 repeating units represented by Formula 2 may be connected to form a polyamic acid polymer.

<Polyimide and polyimide film>

Polyimide according to exemplary embodiments may be manufactured from the diamine compound represented by Formula 1 above. For example, the polyimide may include a structural unit derived from the diamine compound.

In some embodiments, the polyimide may include a repeating unit represented by Formula 3 below.

[Formula 3]

In Formula 3, X, R ¹ and R ² may be as described in Formula 1 above. Ar may be as described in Formula 19 above.

n may be an integer from 10 to 1000.

In one embodiment, the content of the repeating unit represented by Formula 3 may be 80 mol% or more, 90 mol% or more, or 95 mol% or more out of 100 mol% of the total repeating units of the polyimide polymer. For example, the polyimide may be composed of a repeating unit represented by Chemical Formula 3.

According to exemplary embodiments, a method for producing polyimide may use a one-stage polymerization method in which a diamine compound and tetracarboxylic dianhydride are polymerized only at high temperature in the presence of a solvent.

Additionally, a two-stage polymerization method can be used in which polyamic acid is first synthesized at low temperature and then imidized at high temperature. For example, the polyimide may include an imidization reaction product of the polyamic acid.

The reaction temperature of the diamine compound and tetracarboxylic dianhydride may be 300°C or lower. By using the diamine compound represented by Formula 1, the synthesis of polyamic acid and conversion to polyimide can be promoted even at a temperature of 300°C or lower, and, for example, complete imidization can be achieved. As the reaction is performed at a relatively low temperature, rapid reaction and the resulting deterioration of the physical properties of the polymer can be prevented.

When using a one-stage polymerization method, the reaction temperature may be 150°C to 300°C, and the reaction may be performed for 1 hour to 15 hours. When using a two-stage polymerization method, polyamic acid synthesis can be performed at a temperature of 0℃ to 120℃ for 1 hour to 100 hours, and imidization can be performed at a temperature of 0℃ to 300℃ for 1 hour to 15 hours. It can be.

In one embodiment, the oxazolization reaction may proceed simultaneously with the imidation reaction. For example, the polyimide may include a benzoxazole structure. The heat resistance, optical properties, and flexibility of the polymer can be further improved by the benzoxazole structure contained in the main chain of polyimide.

The ratio of the diamine compound represented by Formula 1 to tetracarboxylic dianhydride can be appropriately adjusted depending on the molecular weight of the polyimide polymer. In some embodiments, the molar ratio of the diamine compound to tetracarboxylic dianhydride may be 0.95 to 1.05, preferably 0.98 to 1.02.

Additionally, in order to adjust the molecular weight of the polyimide polymer, monofunctional raw materials such as phthalic anhydride and aniline may be added. In this case, the amount of added raw material may be 2 mol% or less based on the polyimide polymer.

In some embodiments, it is preferable that the solvent used during synthesis is compatible with the diamine and tetracarboxylic dianhydride of Chemical Formula 1, which are raw materials, and the polyimide polymer, which is the product.

For example, as a solvent, phenols such as phenol, 4-methoxyphenol-4-methoxyphenol, 2,6-dimethylphenol, and m-cresol; ethers such as tetrahydrofuran and anisole; Ketones such as cyclohexanone, 2-butanone, methyl isobutyl ketone, 2-heptanone, 2-octanone, and acetophenone; esters such as butyl acetate, methyl benzoate, and γ-butyrolactone; Cellosolves such as butyl cellosolve acetate and propylene glycol monomethyl ether acetate; Amides such as N,N-dimethylformamide, N,N-dimethylacetoamide, and N-methyl-2-pyrrolidone may be used. These may be used alone or in combination of two or more.

In some embodiments, the above-described solvents may be used in combination with aromatic hydrocarbons such as toluene and xylene. In this case, water generated during the imidization reaction can be easily removed by azeotrope.

In some embodiments, the diamine compound may include two or more different compounds represented by Formula 1. In some embodiments, tetracarboxylic dianhydride may include two or more different compounds.

In one embodiment, when two or more types of diamine compounds or two or more types of tetracarboxylic dianhydride are used, the two or more raw materials may be mixed in advance and then polycondensed together. Alternatively, polycondensation can be carried out by adding each raw material in turn while reacting each material individually.

In some embodiments, a dehydrating agent and an imidization catalyst may be added and additionally heated during the imidization process. For example, acid anhydrides such as acetic anhydride, propionic acid anhydride, and trifluoroacetic acid anhydride can be used as the dehydrating agent. For example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used as the cyclization catalyst.

In one embodiment, the amount of the dehydrating agent added may be 1 mole to 10 moles per 1 mole of the diamine compound.

In one embodiment, the added amount of the imidization catalyst may be 0.5 mole to 10 mole per 1 mole of the dehydrating agent.

In one embodiment, the weight average molecular weight of the polyimide may be 50,000 g/mol to 2,000,000 g/mol, or 50,000 g/mol to 200,000 g/mol. For example, the weight average molecular weight is the weight average molecular weight converted to polystyrene and can be measured using gel chromatography (GPC).

Polyimide films according to exemplary embodiments may include the polyimide.

As the polyimide polymer according to exemplary embodiments includes a structural unit derived from a diamine compound represented by Formula 1, it may exhibit high solubility in organic solvents. Therefore, the viscosity of the polyimide solution can be adjusted to an appropriate range and can be easily coated on various substrates.

The organic solvent capable of dissolving the polyimide polymer may be an organic solvent used in polyimide synthesis, an aromatic hydrocarbon-based solvent different from that used during synthesis, a ketone-based solvent, etc.

In one embodiment, a low boiling point aromatic hydrocarbon-based solvent or ketone-based solvent may be used to re-dissolve the purified polyimide polymer by a method such as adding a poor solvent to the prepared polyimide solution and reprecipitating it.

In one embodiment, the substrate on which the polyimide polymer can be coated includes metals such as iron, copper, nickel, and aluminum; inorganic substances such as glass; It may be an organic resin such as epoxy resin or acrylic resin.

In one embodiment, thermosetting properties can be further improved by adding a substance that reacts with the phenol group of the polyimide polymer into the polyimide solution. Substances that react with the phenol group include polyfunctional organic compounds such as resins and oligomers containing two or more functional groups capable of reacting with phenol groups such as carboxyl groups, amino groups, and epoxy groups.

Polyimide films according to exemplary embodiments can be manufactured by curing the polyimide solution.

For example, a polyimide film can be formed by applying a polyimide solution on a substrate and then curing it. After this, the polyimide film can be peeled from the substrate to obtain a polyimide film. The polyimide film can have improved flexibility, optical properties, and heat resistance by including a unit derived from the diamine compound represented by Chemical Formula 1.

The curing process may be performed at a temperature of 80°C to 300°C, preferably 100°C to 250°C. If the curing temperature is less than 80℃, the curing time is long, making it less practical, and storage stability may be reduced when selecting equipment used at low temperatures. In addition, since long-term heating at a temperature higher than 300°C is not required after application, deterioration of the polyimide film due to heat of the substrate can be suppressed.

Transmittance in the visible light region of the polyimide film may be 80% or more. For example, the transmittance of the polyimide film in the 400 nm to 700 nm wavelength range may be 80% or more, and preferably 85% or more. The transmittance may be measured using a UV spectrophotometer for a film with a thickness of 10 μm.

In one embodiment, the thermal decomposition temperature (Td5%) of the polyimide film may be 300°C or higher, and preferably 320°C or higher. For example, the thermal decomposition temperature of the polyimide film may be 300°C to 450°C. The thermal decomposition temperature (Td5%) may be the temperature at which the weight of the film decreases by 5% compared to the initial weight by heating from 0° C. at a temperature increase rate of 10° C./min under a nitrogen gas atmosphere.

In one embodiment, the initial decomposition temperature (IDT) of the polyimide film may be 300°C or higher, and preferably 320°C or higher. The thermal decomposition initiation temperature (IDT) may be the temperature at which the weight of the film begins to decrease when heated at a temperature increase rate of 10°C/min from 0°C in a nitrogen gas atmosphere.

Flexible devices according to example embodiments may include the polybenzoxazole film as a substrate. For example, the flexible device may be a thin film transistor, liquid crystal display (LCD), electronic paper, organic EL display, plasma display panel (PDP), IC card, etc.

Hereinafter, experimental examples including specific examples and comparative examples are presented to aid understanding of the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims, and do not limit the scope and technical idea of the present invention. It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope, and it is natural that such changes and modifications fall within the scope of the appended patent claims.

Examples and Comparative Examples

1. Preparation of polyamic acid polymer

Into a flask equipped with a stirrer, thermometer, dropping device, and nitrogen displacement device, 0.2 mol of tetracarboxylic dianhydride and 200 g of dimethylacetylamide (DMA) shown in Table 1 below were added and dissolved by heating to 50°C and stirring. Afterwards, 0.2 mol of the aromatic diamine of Table 1 below was dissolved in 200 g of dimethylacetylamide (DMA) at room temperature, and then added dropwise over 1 hour using a dropping funnel, followed by stirring at 50°C for 5 hours to form a polyamic acid polymer. was manufactured.

A portion of the reaction mixture was dissolved in DMSO-d6 solvent and NMR (Nuclear Magnetic Resonance) was measured to confirm that diamine was not present in the reaction product. In addition, it was confirmed that polyimic acid was produced through IR measurement.

Figures 1 to 3 are graphs analyzing A-1, A-2, and A-3 by NMR. Specifically, Figure 1 is an NMR spectrum graph of A-1, Figure 2 is an NMR spectrum graph of A-2, and Figure 3 is a graph of A-3.

The NMR data of A-1, A-2, and A-3 are as follows.

^1H NMR(A-1): 10.06(2H), 9.79(2H), 8.05(4H), 7.16(2H), 7.11(4H), 6.99(2H), 6.87(2H), 6.77(4H), 6.60 (4H), 5.50(4H), 4.50(8H)

^1H NMR(A-2): 10.06(2H), 9.79(2H), 8.05(4H), 7.85(4H), 7.82(2H), 7.11(2H), 7.08(2H), 6.77(4H), 6.68 (4H), 5.50(4H), 4.50(8H)

¹ H NMR (A-3): 10.06(2H), 9.79(2H), 8.05(4H), 7.57(2H), 7.08(2H), 6.95(2H), 6.90(2H), 6.77(4H), 6.68 (4H), 5.50(4H), 4.50(8H)

division aromatic diamine Tetracarboxylic dianhydride Example 1 A-1 B-1 Example 2 A-2 B-1 Example 3 A-3 B-1 Comparative Example 1 A-4 B-1 Comparative Example 2 A-5 B-1

The specific compounds used in Table 1 above are as follows.

A-1: Diamine compound represented by formula 5

A-2: Diamine compound represented by Formula 7

A-3: Diamine compound represented by formula 10

A-4: Diamine compound represented by the following formula (a)

[Formula a]

A-5: Diamine compound represented by the following formula (b)

[Formula b]

B-1: Diacid chloride represented by the following formula (15)

[Formula 15]

2. Preparation of polyimide film

The polyamic acid polymer solutions of the above examples and comparative examples were applied on a glass substrate and dried in a hot air dryer at 100°C for 10 minutes to prepare a film with a thickness of 10 μm. In order to imidize the amic acid remaining in the film, it was further heated in an oven at 300°C for 3 hours. Afterwards, the film prepared from the glass substrate was peeled to obtain a polyimide film.

Experimental example: Evaluation of properties of polyimide film

1. Flexibility

The breaking angle was measured while bending the obtained polyimide film. The evaluation criteria are as follows.

<Evaluation criteria>

◎: Does not break even when bent 180 degrees

Ｏ: Broken above 150 degrees and below 180 degrees

×: Broken below 150 degrees

2. Heat resistance

Using a thermogravimetric analysis device (TA instruments, TGA Q50), the temperature at which the weight of the polyimide film was reduced by 5% compared to the initial weight (Td5%) and the thermal decomposition initiation temperature (IDT) were measured, respectively.

Specifically, the temperature was raised from 0°C to 400°C at a temperature increase rate of 10°C/min, and the temperature at which the weight of the polyimide film began to decrease (IDT) and the temperature when the initial weight decreased by 5% (Td5%) were measured. did. The evaluation criteria are as follows.

<Evaluation criteria>

◎: The temperature at which the weight is reduced by 5% and the thermal decomposition start temperature is 320℃ or higher.

Ｏ: The temperature at which the weight is reduced by 5% and the thermal decomposition start temperature is 300 ℃ or more and less than 320 ℃

×: Temperature at which weight is reduced by 5% and thermal decomposition start temperature is less than 300℃

The evaluation results are shown in Table 2 below.

division flexibility heat resistance Example 1 ◎ Ｏ Example 2 ◎ Ｏ Example 3 ◎ Ｏ Comparative Example 1 × × Comparative Example 2 × ◎

Referring to Table 2, the polyimide film manufactured using the diamine compound represented by Formula 1 had both improved flexibility and heat resistance. It can be seen that the polyimide films according to the comparative examples had deteriorated flexibility and relatively reduced heat resistance.

Claims (16)

A diamine compound represented by the following formula (1):
[Formula 1]

(In Formula 1, X is a single bond (direct linkage) or a divalent organic group,
R ¹ and R ² are each independently a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-). The method of claim 1, wherein in Formula 1, R ¹ and R ² are each independently -R ³ -R ⁴ -, and R ³ and R ⁴ are each independently a C1 to C5 alkylene group or C1 to C5 oxyalkylene. Attributable to diamine compounds. The diamine compound according to claim 1, comprising at least one of the compounds represented by the following formulas 4 to 15:
[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]
. A polyamic acid polymer comprising a structural unit derived from the diamine compound according to claim 1. The polyamic acid polymer according to claim 4, comprising a polymer of the diamine compound and an aromatic tetracarboxylic dianhydride compound. The polyamic acid polymer according to claim 4, comprising a repeating unit represented by the following formula (2):
[Formula 2]

⁽ In the above ^formula 2 _,
R ⁵ and R ⁶ are each independently hydrogen, a C1 to C4 alkyl group, or a C1 to C4 alkyl group in which at least one hydrogen is substituted with fluorine, and R ⁵ and R ⁶ may be connected to each other to form a ring,
R ¹ and R ² are each independently a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-),
Ar is a C6 to C40 divalent aromatic hydrocarbon group,
n is an integer from 10 to 1000). A polyimide comprising an imidization reaction product of the polyamic acid polymer according to claim 4. The polyimide according to claim 7, comprising a repeating unit represented by the following formula (3):
[Formula 3]

⁽ In the above ^formula 3 _,
R ⁵ and R ⁶ are each independently hydrogen, a C1 to C4 alkyl group, or a C1 to C4 alkyl group in which at least one hydrogen is substituted with fluorine, and R ⁵ and R ⁶ may be connected to each other to form a ring,
R ¹ and R ² are each independently a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-),
Ar is a C6 to C40 divalent aromatic hydrocarbon group,
n is an integer from 10 to 1000). A polyimide film comprising the polyimide according to claim 7. A flexible device comprising the polyimide film according to claim 9. Preparing a dinitro compound represented by Formula 18 by reacting an acid chloride compound represented by Formula 16 below and an aminoalcohol compound represented by Formula 17 below; and
Method for producing a diamine compound represented by Formula 1 comprising the step of reducing the dinitro compound:
[Formula 16]

[Formula 17]

[Formula 18]

[Formula 1]

(In Formula 1 and Formula 16 to Formula 18, X is a single bond or a divalent organic group,
R, R ¹ and R ² are each a C 2 to C 10 alkylene group or a C 2 to C 10 alkylene group containing at least one ether group (-O-), and R ¹ and R ² are organic groups derived from R. ). A method for producing polyimide, comprising reacting a diamine compound represented by the following formula (1) and a tetracarboxylic dianhydride compound at a temperature of 300°C or lower:
[Formula 1]

(In Formula 1, X is a single bond or a divalent organic group,
R ¹ and R ² are each independently a C2 to C10 alkylene group or a C2 to C10 alkylene group containing at least one ether group (-O-). The method of claim 12, wherein the tetracarboxylic dianhydride compound is an aromatic tetracarboxylic dianhydride compound. The method of claim 12, wherein the step of reacting the diamine compound and the tetracarboxylic dianhydride compound is performed at a temperature of 150°C to 300°C for 1 to 15 hours. The method of claim 12, wherein the step of reacting the diamine compound and the tetracarboxylic dianhydride compound is a first heat treatment step of reacting at a temperature of 0°C to 120°C for 1 to 100 hours, and at a temperature of 0°C to 300°C. A method for producing polyimide, comprising a second heat treatment step performed for 1 to 15 hours. The method of claim 15, wherein the polyamic acid is formed from the diamine compound and the tetracarboxylic dianhydride by the first heat treatment step, and the polyimide is formed from the polyamic acid by the second heat treatment step. method.