WO2019066203A1 - Compound for enhancing adhesion properties of polyimide resin and polyimide copolymer produced using same - Google Patents

Abstract

The present invention provides a novel polyimide resin adhesion enhancer having a fluorene framework, wherein a polyimide film produced using same exhibits conventional properties such as heat resistance and mechanical properties, and maintains adhesion with a carrier substrate while not being affected with respect to retardation even during a high-temperature process.

Description

A compound that improves the adhesion of a polyimide resin and a polyimide copolymer prepared using the compound

The present application is filed on September 28, 2017. Korean Patent Application 10-2017-0125671 and 2018.06.25 filed. Korean Patent Application No. 10-2018-0072773, all of which are incorporated herein by reference in their entirety.

The present invention relates to a novel compound capable of improving the adhesiveness of a polyimide resin and a polyimide copolymer produced by using the same.

In recent years, light weight and miniaturization of products have been emphasized in the field of display. In the case of glass substrates, there is a limit in that they are heavy and broken, and continuous process is difficult. Accordingly, studies have been actively conducted to apply a plastic substrate having a merit that light, flexible, and continuous process can be substituted for a glass substrate to a cell phone, a notebook, and a PDA.

Particularly, polyimide (PI) resin has advantages that it is easy to synthesize, can form a thin film and does not require a crosslinking agent for curing. Recently, it has become lightweight and refinement of electronic products, . In particular, many studies are underway to use PI for a flexible plastic display board having light and flexible properties.

A polyimide (PI) film produced by polymerizing the polyimide resin is generally prepared by solution polymerization of an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid derivative solution, Coated on a silicon wafer or glass, and cured by heat treatment.

In order to use the polyimide resin on a circuit board, a semiconductor substrate, a flexible display substrate, etc., it is necessary to have excellent adhesion with a silicon wafer, glass or metal in addition to physical properties such as heat oxidation, heat resistance, radiation resistance, do.

Generally, an adhesion promoting agent such as a silane compound is used in order to improve the adhesion between the polyimide film and the glass or metal surface. When the adhesion promoting agent is applied to the surface to improve the adhesion, the adhesion promoting agent acts as a foreign substance, May not be smoothly formed, and the coating process after coating may be repeated one more time, resulting in a decrease in cost efficiency.

In addition, when the adhesion promoter is directly added to the polyamic acid, the problem caused by the application can be minimized, but the amino group of the silane compound precipitates as a carboxylic acid and a salt of the polyamic acid, and foreign substances may be formed on the substrate.

Therefore, it is possible to omit the steps for adhering the final product, thereby increasing the productivity and efficiency of the process, and the adhesion of the polyimide resin which can remarkably improve the surface adhesive force while securing excellent mechanical properties without deteriorating the appearance characteristics of the polyimide resin Development of enhancers is needed.

A problem to be solved by the present invention is to provide a novel compound useful as a polyimide resin adhesion promoting agent.

The present invention also provides a polyimide copolymer containing the novel compound as a polyimide resin adhesion promoting agent.

The present invention also provides a polyimide film produced using the polyimide copolymer.

In order to solve the problems of the present invention, there is provided a compound having a structure represented by the following general formula (1a) or (1b).

[Formula 1a]

[Chemical Formula 1b]

In the above general formulas (1a) and (1b)

In formulas Ia and Ib,

X ₁ and X ₂ each independently represent a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a divalent organic group having 3 to 30 carbon atoms which is substituted or unsubstituted by bonding to each other,

X ₃ and X ₄ are each independently a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a substituted or unsubstituted divalent organic group having 3 to 30 carbon atoms bonded to each other,

R ₁ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms,

R ₂ and R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

a and b are each independently an integer of 1 to 3,

n and m are each independently an integer of 0 to 3;

According to one embodiment, the compound of formula (Ia) or (Ib) may be a compound of formula (2a) or (2b).

(2a)

(2b)

In the above formulas (2a) and (2b)

R ₁ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms,

R ₂ and R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

a and b are each independently an integer of 1 to 3,

n and m are each independently an integer of 0 to 3,

The dotted line (------) indicates a bond or a non-bond.

According to one embodiment, the compound of formula (2a) may be selected from compounds of the following formulas (3a) to (3f).

According to one embodiment, the compound of formula (2b) may be selected from compounds of formula (4a) to (4f).

In order to solve the other problems of the present invention,

As the polymerization component, acid dianhydride, diamine and dimethylsiloxane (DMS) -diphenylsiloxane (DPS) oligomer;

A solvent in which the partition coefficient (Log P) at 25 占 폚 is positive; And

There is provided a polyimide copolymer prepared by polymerizing and curing a polyimide precursor composition comprising the compound of Formula 1a or 1b.

According to one embodiment, the domain of the DMS-DPS oligomer is uniformly distributed in the polyimide matrix to a size of 50 nm or less, and the volume occupied by the DMS-DPS domain may be 15 to 30% by volume of the entire volume.

According to one embodiment, the size of the DMS-DPS domain can be between 1 nm and 50 nm.

According to one embodiment, the DMS-DPS oligomer may have the following structure.

[Chemical Formula 6]

In the above formula, p and q are molar fractions, and when p + q = 100, p is 70 to 90 and q is 10 to 30.

According to one embodiment, 0.1 to 10 parts by weight of the polyimide resin adhesion promoter may be added to 100 parts by weight of the polyimide precursor.

According to one embodiment, the acid may include the polyimide resin adhesion promoter in an amount of 0.001 to 0.5 mole per mole of anhydride.

According to one embodiment, the molecular weight of the diamine compound having the structure of Formula 6 may be 4000 g / mol or more.

According to one embodiment, the solvent, which is a positive distribution coefficient (Log P), can be an amide-based solvent.

According to one embodiment, the amide-based solvent is selected from the group consisting of dimethylpropionamide (DMPA), diethylpropionamide (DEPA), N, N-diethylacetamide (DEAc) , N-diethylformamide (DEF), N-ethylpyrrolidone (NEP), and the like.

The present invention also provides a polyimide film made of the polyimide copolymer.

According to one embodiment, the retardation of the polyimide film may be -500 to 500 nm.

According to one embodiment, the adhesion between the polyimide film and the carrier substrate may be 5 gf / in or more.

The present invention provides a novel polyimide resin adhesion promoter having a fluorene skeleton, and it is an object of the present invention to provide a novel polyimide resin adhesion promoter having a fluorene skeleton, The polyimide copolymer does not rise.

1 is a ¹ H NMR spectrum of the compound prepared in Synthesis Example 1.

2 is a ¹ H- ¹ H TOCSY spectrum of the compound according to Synthesis Example 1. FIG.

FIG. 3 shows a comparison of the 1 H NMR spectrum of APTES (3-aminopropyltriethoxysilane) with the compound according to Synthesis Example 1. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, all the compounds or organic groups may be substituted or unsubstituted, unless otherwise specified. Herein, the term "substituted" means that at least one hydrogen contained in the compound or organic group is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, Substituted with a substituent selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, a carboxylic acid group, an aldehyde group, an epoxy group, a cyano group, a nitro group, an amino group, a sulfonic acid group and derivatives thereof.

The present invention provides a compound having a structure represented by the following general formula (1a) or (1b)

[Formula 1a]

[Chemical Formula 1b]

In formulas Ia and Ib,

X1 and X2 each independently represent a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a substituted or unsubstituted divalent organic group having 3 to 30 carbon atoms bonded to each other,

X 3 and X 4 are each independently a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a substituted or unsubstituted divalent organic group having 3 to 30 carbon atoms bonded to each other,

R 1 and R 3 are each independently an alkyl group having 1 to 5 carbon atoms,

R2 and R4 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

a and b are each independently an integer of 1 to 3,

n and m are each independently an integer of 0 to 3;

According to a preferred embodiment, it may be a compound having a structure represented by the following formula (2a) or (2b).

(2a)

(2b)

In formulas (2a) and (2b)

R1, R3, R2, R4, a, b, n and m are as defined above, and the dotted line (------) represents a bond or a non-bond.

Conventionally, in order to improve adhesion between a glass substrate used as a carrier substrate or a glass substrate on which an inorganic layer is deposited, an adhesion promoter is coated on a glass substrate and a film is formed. However, The adhesion promoter of the present invention has a problem in that foreign materials are generated due to the application of the adhesion promoter or an additional coating process is required and the economical efficiency in the process is low. In addition, even when an adhesion promoter is directly added to the polyimide precursor, there is a problem that the amino group is precipitated with the carboxylic acid of the polyamic acid to form a salt and the adhesiveness is lowered.

There is also a prior art in which an adhesion promoting agent is directly added to a polyimide precursor to improve the adhesiveness. However, the retardation value in the thickness direction is increased, which can be used as an adhesion promoting agent. However, There is a problem that the physical properties of the film may be affected. This is because, in the prior art, an adhesion promoter made of dianhydride, which is generally composed of two or more aromatic structures, is used, and since the structure is relatively rigid, a phase retardation phenomenon may occur at this portion after curing.

In addition, when an adhesion promoter containing a flexible structure such as ODPA (4,4'-oxydiphthalic anhydride) is used, the retardation value may not be increased due to the flexibility of the structure but the Tg may tend to be lowered.

Thus, the present inventors have found that when the polyimide precursor is mixed with the polyimide precursor, the polyimide precursor does not precipitate, the generation of foreign matter can be minimized, the adhesion to the substrate is excellent, A study was made on adhesion promoting agents which do not affect.

The compound that can be used as an adhesion promoter according to the present invention has a fluorene skeleton similar to the structure of the general formula (1a) or (1b), so that the intermolecular free volume is generated due to the fluorene skeleton while maintaining the effect of adhesion enhancement It does not affect packing density. In addition, a high heat-resistant polyimide film which does not affect the retardation value in the thickness direction and the heat resistance, which is an optical characteristic of a polyimide film having excellent heat resistance due to the structural characteristic including a large amount of aromatic groups, can be provided.

An adhesion promoter having the structure of formula (Ia) can be prepared by the reaction of an acid anhydride containing a fluorene structure with aminopropyltetraethoxysilane,

An adhesion promoter having the structure of formula (Ib) can be prepared from the reaction of a diamine containing a fluorene structure with tetraethoxysilane having an anhydride end.

Particularly, the compound of formula (I) or (Ib) can be converted into a silanol group (Si-OH) by an alkoxysilane (Si-OR) moiety by water or moisture, and the silanol group can undergo condensation reaction with glass or metal, It can be strongly bonded to the surface of glass or metal.

According to one embodiment, the compound of formula (Ia) may be selected from compounds of the following formulas (3a) to (3f).

In the above formulas (3a) to (3f), R1 and R2 are the same as defined in formula (1a).

According to one embodiment, the compound of formula (Ib) may be selected from compounds of the following formulas (4a) to (4f).

In the above formulas (4a) to (4f), R3 and R4 are the same as defined in formula (1b).

The present invention also relates to

As the polymerization component, acid dianhydride, diamine and dimethylsiloxane (DMS) -diphenylsiloxane (DPS) oligomer;

Partition coefficient (Log P); And

There is provided a polyimide copolymer prepared by polymerizing and curing a polyimide precursor composition comprising the compound of Formula 1a or 1b as a polyimide resin adhesion promoting agent.

According to one embodiment, the DMS-DPS domain is uniformly distributed in the polyimide matrix to a size of 50 nm or less, and the volume occupied by the DMS-DPS domain may be 15 to 30% by volume of the total volume. The size of the DMS-DPS domain is preferably 1 nm to 50 nm, or 5 nm to 40 nm, or 10 nm to 30 nm, for uniform distribution.

According to one embodiment, the adhesion promoting agent may be included in an amount of 0.001 to 0.5 mole ratio relative to 1 mole of the acid anhydride.

The adhesion promoter may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polyimide precursor.

According to one embodiment, the adhesion promoter may be included in the polyimide precursor composition to form a structure of the following formula 5a or 5b.

[Chemical Formula 5a]

[Chemical Formula 5b]

Wherein R 1, R 2, R 3, R 4, a, b, n and m are the same as defined in the formulas (1a) and (1b)

Wherein Z is a residue derived from a tetracarboxylic dianhydride,

Y is a residue derived from a diamine.

That is, the adhesion promoter of one embodiment is bonded to the end of the repeating unit of the polyamic acid produced by the reaction of the tetracarboxylic dianhydride with the diamine as shown in the above formula (5a) or (5b) It is possible to provide a polyimide resin which not only does not generate salt due to reaction with acid and can increase the adhesive force but also does not increase the retardation in the thickness direction due to the fluorene structure.

According to one embodiment, the DMS-DPS oligomer may have the structure of the following formula (6).

[Chemical Formula 6]

In the above formula, p and q are molar fractions, and when p + q = 100, p is 70 to 90 and q is 10 to 30.

The molecular weight of the diamine compound having the structure of Formula 6 may be 4000 g / mol or more, preferably 4400 g / mol or more, and more preferably 5000 g / mol or more. Here, the molecular weight means the weight average molecular weight, and the molecular weight can be calculated by calculating the amine equivalent using NMR analysis or acid-base titration.

If the molecular weight of the diamine having the structure of Formula 6 is less than 4000 g / mol, the heat resistance may be lowered. For example, when the glass transition temperature (Tg) of the produced polyimide is decreased or the thermal expansion coefficient is excessive .

According to one embodiment, at least one diamine may be used in the present invention, and the diamine of Formula 6 may be contained in an amount of 1 to 20 mol%, preferably 1 to 10 mol%, of the total diamine.

According to one embodiment, the diamine of formula (6) may be present in an amount of 10 to 50% by weight, based on the total solid content of the polyimide copolymer, that is, the weight of the solid content of the polyimide precursor or the total weight of the polymerization components (diamine and acid dianhydride) By weight, preferably 10 to 40% by weight. When the diamine containing the structure of Formula 6 is added in excess of the total weight of the polymer, for example, 50 wt% or more, or 40 wt% or more, mechanical properties such as modulus of the polyimide And the film strength is decreased, so that physical damage such as tearing of the film in the process can occur. In addition, when the diamine having the structure of Formula 6 is added in excess, Tg derived from the polymer having the siloxane structure may be exhibited. From this, Tg appears at a low process temperature of 350 DEG C or lower, In the inorganic film deposition process, wrinkles occur on the surface of the film due to the flow phenomenon of the polymer, and the inorganic film may be cracked.

According to the present invention, since the size of the DMS-DPS domain distributed in the polyimide matrix has a nano-size, for example, 1 nm to 50 nm, or 5 nm to 40 nm, or 10 nm to 30 nm as a continuous phase, heat resistance and mechanical properties are maintained So that the residual stress can be minimized. In the case of not having such a continuous phase, the effect of decreasing the residual stress may be obtained, but the heat resistance and the mechanical properties are remarkably reduced, making it difficult to use in the process.

Herein, the DMS-DPS domain means a distributed region of the polymer of the DMS-DPS structure, and the size thereof refers to the diameter of the circle surrounding the region.

It is preferable that the portions (domains) including the DMS-DPS structure are connected in a continuous phase in the polyimide matrix. Here, the term " continuous phase " means a shape in which nano-sized domains are uniformly distributed.

Accordingly, the present invention can provide a polyimide having uniform transparency without phase separation in a polyimide matrix, thereby lowering the haze property and obtaining more transparent polyimide, The presence of the DPS structure in a continuous phase can improve the mechanical strength and the stress relaxation effect of the polyimide more efficiently. From these characteristics, the composition according to the present invention can provide a flat polyimide film with reduced thermal and optical properties as well as a phenomenon in which the substrate is warped after coating-curing.

By inserting the structure of formula (6) containing a siloxane structure into the polyimide structure, the present invention can improve the modulus strength of the polyimide and alleviate stress caused by external force. At this time, the polyimide including the siloxane structure may exhibit polarity, and the polyimide structure not including the siloxane structure may undergo phase separation due to the difference in polarity. As a result, the siloxane structure may be unevenly distributed throughout the polyimide structure . In this case, it is difficult to improve the physical properties such as the strength improvement and stress relaxation effect of the polyimide due to the siloxane structure, and the transparency of the film may be deteriorated due to an increase in haze due to phase separation. In particular, in the case where the diamine containing a siloxane structure has a high molecular weight, the polyimide prepared from the diamine has a more pronounced polarity, and the phenomenon of phase separation between polyimides can be more clearly seen. However, when a siloxane diamine having a low molecular weight structure is used, a large amount of the siloxane diamine should be added in order to exhibit an effect such as stress relaxation. This may cause a process problem such as generation of Tg at a low temperature, The physical properties of the polyimide film may be deteriorated. Therefore, when a high molecular weight siloxane diamine is added, a relaxation segment can be formed in a large molecule, and therefore, the stress relaxation effect can be effectively exhibited even with a low content compared to adding a low molecular weight. Thus, the present inventors have studied a method for making the diamine of formula (VI) having a high molecular weight siloxane structure more uniformly distributed on the polyimide matrix without phase separation.

INDUSTRIAL APPLICABILITY The present invention can provide a polyimide film which is colorless and transparent and has excellent heat resistance, by producing polyimide by polymerizing an organic solvent having a positive distribution coefficient (Log P) using a diamine containing a Si structure having a high molecular weight.

The amphiphilic solvent may be selected from the group consisting of dimethylpropionamide (DMPA), diethylpropionamide (DEPA), N, N-diethylacetamide (N, N-diethylacetamide, DEAc), N, N-diethylformamide (DEF), N-ethylpyrrolidone (NEP).

The polyimide copolymer according to the present invention can reduce the phase separation depending on the polarity difference between the flexible polyimide repeating structure into which the structure of Chemical Formula 6 is introduced and the other polyimide structure by using the organic solvent as described above have. Conventionally, two kinds of organic solvents have been used to solve the phase separation problem. However, the present invention can reduce the whitening phenomenon due to phase separation even when one kind of organic solvent is used, so that a more transparent polyimide film can be manufactured have.

On the other hand, there is a method in which a polar solvent and a non-polar solvent are mixed to solve the opacity phenomenon. However, since a polar solvent has high volatility, it can be volatilized beforehand in a manufacturing process, Lt; / RTI > In addition, the problem of phase separation can not be completely solved, resulting in high haze and low transparency of the polyimide film produced.

In the present invention, in order to uniformly distribute the polyimide structure containing the structure of formula (6) in the overall polyimide matrix, a solvent having a positive logarithm (log P), particularly an amide-based solvent in which Log P is positive, is used. More specifically, by using a solvent containing a molecular structure having both affinity, it is possible not only to solve the process problem of using a polar solvent but also to use only one kind of solvent due to a molecular structure having both affinity The polyimide can be evenly distributed and is therefore very suitable for solving the problems due to phase separation. As a result, polyimide having significantly improved haze characteristics can be provided.

According to one embodiment, the dianhydride may be selected from tetracarboxylic dianhydrides containing a tetravalent organic group of the following general formulas (7a) to (7h) in the molecular structure.

[Formula 7a]

[Formula 7b]

[Formula 7c]

[Formula 7d]

[Formula 7e]

[Formula 7f]

[Formula 7g]

[Chemical Formula 7h]

In the general formulas (7a) to (7h), R11 to R24 each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br, and -I, a hydroxyl group (-OH), a thiol group A nitro group (-NO 2), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms,

A3 is an integer of 0 to 8; a4 and a5 are each independently an integer of 0 to 3; and a7 and a8 are each independently an integer of 0 to 3, and a1 is an integer of 0 to 2, a2 is an integer of 0 to 4, a3 is an integer of 0 to 8, A15 and a16 are each independently an integer of 0 to 4, a17 and a18 are each independently an integer of 0 to 4, and a10 and a12 are each independently an integer of 0 to 3, a11 is an integer of 0 to 4, And a6, a9, a13, a14, a19 and a20 are each independently an integer of 0 to 3,

n is an integer of 1 to 3,

A11 to A16 each independently represent -O-, -CR'R "-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -, a phenylene group, and a combination thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Lt; / RTI >

According to one embodiment, the diamine may include diamines containing a divalent organic group of the following formula (8) in the molecular structure in an amount of 80 to 99 mol% based on the total diamine content.

[Chemical Formula 8]

In Formula 8,

R31 and R32 each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group (-NO2) A cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms, preferably a halogen atom, An alkyl group, an alkyl group, an aryl group, and a cyano group. For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group is a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro atom, such as a fluoromethyl group, a perfluoroethyl group, And the alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group , And more preferably a fluoro atom and a fluoro atom such as a fluoroalkyl group.

Q is a single bond, -O-, -CR'R "-, -C (═O) -, -C (═O) O-, -C (═O) NH-, -S-, A phenylene group and a combination thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms .

Here, the 'fluoro-based substituent' of the present invention means not only a 'fluoro atom substituent' but also a 'substituent group containing a fluoro atom'.

The diamine of formula (8) may be selected from compounds represented by the following formulas (8a) to (8d).

In Formulas (8a) to (8d), Q is as described above.

According to one embodiment, the tetracarboxylic dianhydride may include a tetracarboxylic dianhydride having a structure represented by the following formula (9) in an amount of 20 to 80 mol% in the total tetracarboxylic dianhydride, Preferably 30 to 80 mol%, more preferably 30 to 70 mol%.

[Chemical Formula 9]

According to one embodiment, the tetracarboxylic acid dianhydride may include a tetracarboxylic acid dianhydride having a structure represented by the following formula (10) in an amount of 20 to 80 mol% in the entire tetracarboxylic dianhydride, , Preferably 20 to 60 mol%, more preferably 20 to 50 mol%.

[Chemical formula 10]

In Formula 10,

Q1 and Q2 each independently represent a single bond, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO2-, And combinations thereof.

According to one embodiment, the formula (10) may be a compound of the following formulas (10a) to (10e).

By including the fluorene structure in the polyimide structure, the retardation in the thickness direction of the film can be reduced.

The present invention can use at least one selected from the tetracarboxylic acid dianhydrides including the tetravalent organic group structure represented by the following general formulas (11a) to (11r).

Wherein A2 is selected from the group consisting of a single bond, -O-, -C (= O) -, -C (= O) NH-, -S-, -SO2-, And v is an integer of 0 or 1, and in 11r, x is an integer of 1 to 10.

At least one hydrogen atom present in the tetravalent organic groups of 11a to 11r is a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group -SH), a nitro group (-NO2), a cyano group, an alkyl group having 1 to 10 carbon atoms, halogenoalkoxy having 1 to 4 carbon atoms, halogenoalkyl having 1 to 10 carbon atoms, or aryl group having 6 to 20 carbon atoms . ≪ / RTI >

Alternatively, the present invention can use the tetracarboxylic dianhydrides of the above general formulas (9) and (10) together. When the tetracarboxylic acid dianhydrides of the general formulas (9) and (10) are used together, the tetracarboxylic acid dianhydride The content of the tetracarboxylic dianhydride of the formula (10) may be 10 to 30 mol%, preferably 10 to 25 mol%, more preferably 15 to 25 mol%, based on the total content of water . The compound represented by the formula (10) containing the fluorene structure is used in the production of the polyimide together with the compound represented by the formula (9), thereby alleviating the heat shrinkage in the plane direction, The improvement of the phenomenon and the heat resistance such as the glass transition temperature can be improved.

According to one embodiment of the present invention, the total content of the tetracarboxylic dianhydride and the content of the diamine may be reacted in a molar ratio of 1: 1.1 to 1.1: 1, and preferably, in order to improve the reactivity and the processability, It is preferable that the total content of the tetracarboxylic dianhydride is excessively reacted with respect to the diamine or that the content of the diamine is excessively reacted with respect to the total content of the tetracarboxylic dianhydride.

According to one embodiment of the present invention, it is preferable that the molar ratio of the total content of the tetracarboxylic dianhydride to the content of the diamine is 1: 0.99 to 0.99: 1, preferably 1: 0.98 to 0.98: 1 .

The organic solvent that can be used in the polymerization reaction may be a positive integer having a partition coefficient (Log P value) at 25 ° C and a boiling point of 180 ° C or less. More specifically, the LogP value may be 0.01 to 3, 2, or 0.1 to 2.

The partition coefficient can be calculated using the ACD / LogP module of the ACD / Percepta platform of ACD / Labs. The ACD / LogP module can calculate the quantitative structure-property relationship (QSPR) .

When the distribution coefficient value is a positive number, it means that the polarity of the solvent is hydrophobic. According to the studies of the inventors of the present invention, when a polyimide precursor composition is prepared using a specific solvent having a logarithm of log P value, dewetting can be improved. Further, by using a solvent having a positive Log P value, it is possible to control the liquid caking phenomenon of the solution without using an additive that controls the surface tension such as a leveling agent and the smoothness of the coating film. By doing so, it is possible to eliminate the quality and process problems such as the inclusion of low-molecular substances in the final product because no additional substances such as additives are used, and it is possible to form polyimide films having uniform properties more efficiently It is effective.

For example, in the step of coating a polyimide precursor composition on a glass substrate, the solution may be curled due to shrinkage of the coating layer during curing or under the condition of leaving the coating solution in a humidity condition. Liquid curling of such a coating solution leads to a variation in the thickness of the film, which leads to insufficient bending resistance of the film, which may result in breakage of the film or breakage of corners at the time of cutting. That is, there is a problem that the processability is poor and the yield is lowered.

In addition, the polyimide precursor solution containing a polar solvent having a negative logarithm of Log P may have a scattered coating around the region where the foreign matter exists due to the polarity of the foreign matter when the polarized micro- Cracks or thickness variations may occur. On the other hand, when a hydrophobic solvent having an affinity for Log P is used, coating cracking, thickness change and the like can be reduced or suppressed even when a foreign substance having polarity is introduced.

Specifically, the polyimide precursor composition comprising a solvent in which Log P is positive may have a dewetting ratio defined by the following formula 1: 0% to 0.1% or less.

[Formula 1]

Curling rate (%) = [(A-B) / A] x 100

In the above formula (1)

A: An area of the polyimide precursor composition coated on a substrate (100 mm x 100 mm)

B: Area after curling occurs from the edge of the substrate coated with the polyimide precursor composition or PI film.

The dewetting phenomenon of the polyimide precursor composition and the film may occur within 30 minutes after coating the solution of the polyimide precursor composition, and in particular, the thickness of the edge is increased by starting to dry from the edge.

After coating the substrate with the polyimide precursor composition according to the present invention, the coated resin composition solution is allowed to stand in a humidity condition for 10 minutes or more, for example, 10 minutes or more, for example, 40 minutes or more for a drying rate of 0.1 50%, 60%, 70% or more of the humidity condition in the range of 40% to 80%, for example, at a temperature of 20 to 30 DEG C, , Even after being left for 10 to 50 minutes under a humidity condition of 50%, for example, at a humidity of 80%, and a humidity of 0.1% or less, preferably 0.05% It is possible to show a curling rate close to 0%.

For example, the polyimide precursor composition is coated on a substrate and then dried at a temperature of at least 10 minutes, for example, at a temperature of 20 to 30 DEG C under a humidity condition of 40% or more, more specifically, Is left for 10 to 50 minutes under a humidity condition ranging from 40% to 80%, that is, at a humidity condition of, for example, 40%, 50%, 60%, 70% The curling rate of the polyimide film may be 0.1% or less, that is, the curling process may hardly occur or disappear even in the curing process by the heat treatment, and specifically, the curling rate close to 0.05%, more preferably nearly 0% .

The polyimide precursor composition according to the present invention can solve this liquid curl phenomenon, thereby making it possible to obtain a polyimide film having more uniform characteristics, thereby further improving the yield of the production process.

In addition, the density of the solvent according to the present invention may be 1 g / cm 3 or less as measured by the standard measurement method of ASTM D1475. If the density is 1 g / cm 3 or more, the relative viscosity may be increased, .

The reaction of the tetracarboxylic dianhydride and the diamine can be carried out by a usual polyimide precursor polymerization method such as solution polymerization. Specifically, after the diamine is dissolved in an organic solvent, the tetracarboxylic acid may be subjected to a polymerization reaction by adding an anhydride.

The polymerization reaction may be carried out under an inert gas or a nitrogen stream, and may be carried out under anhydrous conditions.

The reaction temperature during the polymerization reaction may be -20 to 80 ° C, preferably 0 to 80 ° C. If the reaction temperature is too high, the reactivity may become high and the molecular weight may become large, and the viscosity of the precursor composition may increase, which may be unfavorable in the process.

The polyimide precursor composition preferably contains a solid content in such an amount that the composition has an appropriate viscosity in consideration of coating properties during the film forming step and the like. According to one embodiment, the content of the composition can be controlled so that the total polyimide precursor content is 8 to 25 wt%, preferably 10 to 25 wt%, more preferably 10 to 20 wt% have.

Alternatively, the polyimide precursor composition may be adjusted to have a viscosity of 3,000 cP or more, or 4,000 cP or more, and the viscosity of the polyimide precursor composition is 10,000 cP or less, preferably 9,000 cP or less, more preferably 8,000 cP or less Of the total weight of the composition. When the viscosity of the polyimide precursor composition exceeds 10,000 cP, the efficiency of defoaming at the time of processing the polyimide film is lowered. As a result, not only the process efficiency but also the surface roughness of the produced film is poor due to bubbling, so that the electrical, optical and mechanical properties Can be degraded.

The molecular weight of the polyimide according to the present invention may be 10,000 to 200,000 g / mol, or 20,000 to 100,000 g / mol, or 30,000 to 100,000 g / mol. The molecular weight distribution (Mw / Mn) of the polyimide according to the present invention is preferably 1.1 to 2.5. If the weight average molecular weight or the molecular weight distribution of the polyimide is out of the above range, film formation may be difficult or characteristics of the polyimide-based film such as transparency, heat resistance and mechanical properties may be deteriorated.

Next, the polyimide precursor obtained as a result of the polymerization reaction is imidized to prepare a transparent polyimide film. At this time, the imidization process may be specifically a chemical imidization or thermal imidization process.

For example, after adding a dehydrating agent and an imidation catalyst to the polymerized polyimide precursor composition, the polymerized polyimide precursor composition is heated to a temperature of 50 to 100 ° C and imidized by a chemical reaction, or alcohol is removed by refluxing the solution, Polyimide can be obtained by heating.

In the above chemical imidization method, pyridine, triethylamine, picoline or quinoline may be used as the imidization catalyst. In addition, a nitrogen-containing heterocyclic compound substituted or unsubstituted, a nitrogen-containing heterocyclic compound N- A substituted or unsubstituted amino acid compound, an aromatic hydrocarbon compound having a hydroxyl group or an aromatic heterocyclic compound, particularly 1,2-dimethylimidazole, N-methylimidazole, N-benzyl- Lower alkyl imidazole such as methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole and 5-methylbenzimidazole, isoquinoline, 3,5-dimethylpyridine, 3,4 Substituted pyridines such as dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine and 4-n-propylpyridine, and p-toluenesulfonic acid.

As the dehydrating agent, an acid anhydride such as acetic anhydride can be used.

Alternatively, the polyimide precursor composition can be imidized by applying the polyimide precursor composition onto a substrate and then heat-treating the polyimide precursor composition.

The polyimide precursor composition may be in the form of a solution in which the polyimide precursor is dissolved in an organic solvent. For example, when the polyimide precursor is synthesized in an organic solvent, the solution may be the reaction solution to be obtained, or the reaction solution may be diluted with another solvent. When the polyimide precursor is obtained as a solid powder, it may be a solution prepared by dissolving the polyimide precursor in an organic solvent.

A method for producing a film with a polyimide precursor solution according to the present invention comprises:

Applying the polyimide precursor solution onto a substrate;

And heat treating the applied polyimide precursor solution.

In this case, the substrate may be glass, metal substrate, plastic substrate, or the like without any particular limitation. Among these, the polyimide precursor is excellent in thermal and chemical stability during the imidation and curing process, A glass substrate that can be easily separated without damage to the subsequently formed polyimide-based film may be desirable.

Specific examples of the coating method include a spin coating method, a bar coating method, a roll coating method, an air-knife method, a gravure method, a reverse roll method, a kiss roll method, a doctor blade method, A spray method, a dipping method, a brushing method, or the like may be used. Of these, it is more preferable to carry out the continuous process and to perform the casting method which can increase the imidization rate of the polyimide.

The polyimide precursor composition may also be applied over the substrate to a thickness range such that the polyimide film to be finally prepared has a thickness suitable for the display substrate.

Specifically, it may be applied in an amount such that the thickness is 10 to 30 mu m. After the application of the polyimide precursor composition, a drying process for removing the solvent present in the polyimide precursor composition prior to the curing process may be further optionally performed.

The drying process may be carried out according to a conventional method, specifically at a temperature of 140 ° C or lower, or 80 ° C to 140 ° C. If the drying temperature is lower than 80 캜, the drying process becomes longer. If the drying temperature is higher than 140 캜, the imidization rapidly proceeds to make it difficult to form a polyimide film having a uniform thickness.

Then, the polyimide precursor composition is coated on a substrate and heat-treated on an IR oven, a hot air oven, or a hot plate. The heat treatment temperature may range from 300 to 500 ° C, preferably from 320 to 480 ° C, And may be performed in a multi-step heating process within a temperature range. The heat treatment process may be performed for 20 to 70 minutes, and preferably for 20 to 60 minutes.

Thereafter, the polyimide film formed on the substrate can be produced from the substrate by a conventional method to produce a polyimide film.

The organic solvent contained in the polyimide precursor composition of the present invention may be the same as the organic solvent used in the polymerization reaction.

In the present invention, a silane coupling agent, a crosslinkable compound, an imidization accelerator for promoting imidization efficiently, and the like may be added as long as the effect is not impaired.

The polyimide-based film may have a haze of 2 or less, preferably 1 or less, or 0.9 or less, thereby providing a polyimide film with improved transparency. At this time, the thickness of the polyimide film may be 8 to 15 탆, preferably 10 to 12 탆.

Further, it is preferable that the transmittance to light at a wavelength of 380 to 760 nm is 80% or more and the yellowness degree (YI) is about 15 or less, preferably about 10 or less, more preferably about 8 or less Lt; RTI ID = 0.0 > polyimide < / RTI > By having excellent light transmittance and yellowness as described above, it is possible to exhibit significantly improved transparency and optical characteristics.

The polyimide film according to the present invention may have a glass transition temperature (Tg) of 350 ° C or higher, preferably 360 ° C or higher, and more preferably 370 ° C or higher.

In addition, the polyimide film according to the present invention may have excellent thermal stability depending on the temperature change. For example, the polyimide film according to the present invention may have a thermal expansion coefficient of -10 To 100 ppm / 占 폚, preferably from -7 to 90 ppm / 占 폚, more preferably 80 ppm / 占 폚 or lower.

In addition, the compound of formula (I) or (Ib) according to the present invention can reduce the phase difference of the film while maintaining the characteristics of the polyimide film by introducing fluorene structure into the structure. For example, the polyimide film containing the above compound as an adhesion promoter has an in-plane retardation (Rin) of about 0 to 100 nm, a retardation value (Rth) in the thickness direction of about -1000 to 1000 nm, Preferably from -600 to 600 nm, more preferably from -500 to 500 nm, or from -200 to 200 nm. When the thickness direction retardation is 1000 nm or more and -1000 nm or more, a phase difference is generated in the polyimide film and the light is distorted. As a result, the visibility can be remarkably lowered have.

According to one embodiment, the adhesion strength of the polyimide film including the adhesion promoter to the carrier substrate may be 5 gf / in or more, and preferably 10 gf / in or more.

The present invention provides a new compound useful as an adhesion promoter for polyimide resins, which enables polyimide films to exhibit adhesion to a carrier substrate even at high temperatures while maintaining conventional properties such as high transparency, heat resistance, mechanical properties and low residual stress Can be maintained.

In another embodiment of the present invention, there is provided a molded article comprising the polyimide copolymer.

The polyimide copolymer according to the present invention can be used for a protective film for a circuit board, a base film of a circuit substrate, an insulating layer of a circuit substrate, an interlayer insulating film of a semiconductor, a solder resist, a flexible circuit substrate, or a flexible display substrate, But is not limited to, OLED devices using a low temperature polysilicon (LTPS) process that requires process steps.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

≪ Synthesis Example 1 &

Compounds having the structure of formula (20) were prepared through the reaction of scheme (1).

[Chemical Formula 20]

More specifically, 1463 g of DEAc (diethylacetamide) was charged into a reactor through which a nitrogen gas flow was passed, and then 0.916 mol of one-end amine-modified APTES (3-Aminopropyltriethoxysilane) was added at the same temperature while the temperature of the reactor was maintained at 25 ° C to dissolve . To the solution to which APTES was added, 0.458 mol of BPAF (9,9'-bis (3,4-dicaroxyphenyl) fluorene dianhydride) was added at the same temperature and stirred for 24 hours. 1H-NMR of the synthesized compound is shown in FIGS. 1 and 2. FIG. 3 shows the 1H-NMR peak of the compound of Formula 20 and APTES in comparison with each other.

[Reaction Scheme 1]

<NMR Measurement Method>

Bruker 700 MHz NMR spectroscopy was performed using an acetone-d6-filled insert tube.

As can be seen from the measurement results of 1H NMR spectrum in FIGS. 1 to 3, it can be seen that the synthesis reaction proceeded because the (CO) NCH 2 peak generated by the reaction of APTES monomer with BPAF was confirmed at around 3.4 ppm.

&Lt; Synthesis Example 2 &

Synthesis was carried out according to Reaction Scheme 2 using BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride) instead of BPAF in the same manner as in Synthesis Example 1.

[Reaction Scheme 2]

&Lt; Polymerization Example 1 &

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (124 g) was charged into a reactor through which nitrogen gas flow was passed. The reactor was maintained at a temperature of 25 ° C and a two-terminal amine-modified DMS-DPS (molecular weight: 5700 g / 73.3, q = 26.7) and 0.0390 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.032 mol of PMDA and 0.008 mol of BPAF (9,9'-bis (3,4-dicaroxyphenyl) fluorene dianhydride) were added to the solution to which DMS-DPS and TFMB were added at the same temperature and stirred for 3 hours, And stirred for 4 hours.

The DMS-DPS structure is as follows.

In the above formula, p and q are molar fractions, and when p + q = 100, p is 70 to 90 and q is 10 to 30.

&Lt; Example 1 >

To the polyimide precursor solution prepared in Polymerization Example 1, 0.5 part by weight of the compound obtained in Synthesis Example 1 was added based on 100 parts by weight of polyamic acid.

&Lt; Comparative Example 1 &

0.5 part by weight of the compound obtained in Synthesis Example 2 was added to the polyimide precursor solution prepared in Polymerization Example 1 based on 100 parts by weight of polyamic acid.

<Experimental Example>

Each of the polyimide precursor solutions prepared in Example 1 and Comparative Example 1 was spin-coated on a glass substrate. The glass substrate coated with the polyimide precursor solution was placed in an oven, heated at a rate of 5 ° C / min, and cured at 80 ° C for 30 minutes and at 400 ° C for 30 minutes to produce a polyimide film.

The YI, Rth and Tg of the polyimide film were measured and are shown in Table 1 below.

<Yellowness index (YI)>

Yellowness (YI) was measured with Color Eye 7000A.

<Thickness direction phase difference>

The thickness direction retardation (Rth) was measured using Axoscan. The thickness of the film was measured by cutting the film to a certain size, and then the thickness (nm) measured while correcting the C-plate direction was input to compensate the retardation value by measuring the phase difference using Axoscan.

&Lt; Glass transition temperature (Tg) >

Cut the film to 5 x 20 mm and prepare the sample and load the sample using the accessories. The actual measured film length was equal to 16 mm. The film was pulled up at a rate of 5 DEG C / min in a temperature range of 100 to 400 DEG C with a pulling force of 0.02 N, and then heated at a cooling rate of 4 DEG C / min in a temperature range of 400 to 100 DEG C After cooling, the secondary heating step was carried out at a heating rate of 5 ° C / min at a temperature range of 100 to 450 ° C, and the change in thermal expansion was measured by TMA (Q400, TA company).

At this time, the inflection point shown in the temperature rising section in the second heating step was defined as Tg.

<Peel Strength Measurement>

The peel strength (adhesive strength) of the polyimide film produced by the above method was measured with a film strength analyzer (TA-XT Plus, Texture Analyzer), and a sample was formed with a measurement length of 10 mm at a film width of 2.54 cm. Was measured.

	Example 1	Comparative Example 1
DMS-DPS Mw	5700	5700
Organic solvent	DEAc	DEAc
DMS-DPS content (wt%)	20	20
PI molecular weight	59400	59400
Solid content (% by weight)	17.3	17.3
Content of new adhesion promoting agent (% by weight)	0.5	0.5
Viscosity (cP)	4800	4700
Thickness (μm)	10.1	10.1
YI	5.8	5.8
Rth (nm)	480	550
Tg (占 폚)	ND	ND
Peel strength (gf / in)	20	20

As can be seen from the results of Table 1, the polyimide film of Example 1 including the adhesion promoter according to the present invention maintained Rth at a low level while maintaining high peel strength, but it was found that Rth increased in Comparative Example 1 have.

Accordingly, it can be seen that the polyimide resin adhesion promoter according to the present invention can provide polyimide having high heat resistance characteristics while improving the bonding strength.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (14)

1. A compound represented by the following formula (1a) or (1b):

   [Formula 1a]

   

   [Chemical Formula 1b]

   

   In formulas Ia and Ib,

   X ₁ and X ₂ each independently represent a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a divalent organic group having 3 to 30 carbon atoms which is substituted or unsubstituted by bonding to each other,

   X ₃ and X ₄ are each independently a substituted or unsubstituted divalent organic group having 1 to 30 carbon atoms or a substituted or unsubstituted divalent organic group having 3 to 30 carbon atoms bonded to each other,

   R ₁ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms,

   R ₂ and R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

   A and b are each independently an integer of 1 to 3,

   N and m are each independently an integer of 0 to 3;
2. The compound according to claim 1, wherein the compound of formula (1a) or (1b) has the structure of formula (2a) or (2b)

   (2a)

   

   (2b)

   

   In formulas (2a) and (2b)

   R ₁ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms,

   R ₂ and R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

   A and b are each independently an integer of 1 to 3,

   N and m are each independently an integer of 0 to 3,

   The dotted line (------) indicates a bond or a non-bond.
3. The method according to claim 1,

   Wherein the compound of formula (Ia) is selected from compounds of the following formulas (3a) to (3f):

   

   .
4. The method according to claim 1,

   Wherein the compound of formula (Ib) is selected from compounds of the following formulas (4a) to (4f):

   
5. As the polymerization component, acid dianhydride, diamine and dimethylsiloxane (DMS) -diphenylsiloxane (DPS) oligomer;

   A solvent in which the partition coefficient (Log P) at 25 占 폚 is positive; And

   A polyimide copolymer produced by polymerizing and curing a polyimide precursor composition comprising the compound according to claim 1.
6. 6. The method of claim 5,

   Wherein the DMS-DPS oligomer has a structure represented by the following formula (6): &lt; EMI ID =

   [Chemical Formula 6]

   

   In the above formula, p and q are molar fractions, and when p + q = 100, p is 70 to 90 and q is 10 to 30.
7. 6. The method of claim 5,

   Wherein the polyimide precursor composition comprises 0.1 to 10 parts by weight of the compound according to claim 1 per 100 parts by weight of the polyimide precursor composition.
8. 6. The method of claim 5,

   Wherein the acid dianhydride comprises the compound according to claim 1 in an amount of 0.001 to 0.5 mole per mole of the anhydride.
9. The method according to claim 6,

   Wherein the diamine compound having the structure of Formula (6) has a weight average molecular weight of 4000 g / mol or more.
10. 6. The method of claim 5,

    Wherein the solvent having a positive distribution coefficient (Log P) at 25 占 폚 is an amide-based solvent.
11. 11. The method of claim 10,

    Wherein the amide solvent is selected from the group consisting of dimethylpropionamide (DMPA), diethylpropionamide (DEPA), N, N-diethylacetamide (DEAc), N, At least one selected from the group consisting of N, N-diethylformamide (DEF) and N-ethylpyrrolidone (NEP).
12. A polyimide film produced from the polyimide copolymer according to claim 5.
13. 13. The method of claim 12,

    Wherein the polyimide film has a retardation of -500 to 500 nm.
14. 13. The method of claim 12,

    Wherein the adhesion between the polyimide film and the carrier substrate is 5 gf / in or more.

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