KR102013534B1 - Polyamic Acid Composition for Display Substrate and Method for Manufacturing Display Substrate by Using the Same - Google Patents

Abstract

The present invention provides a polyamic acid composition having an adhesion force of 0.05 to 0.1 N/cm with amorphous silicon in a state of being cured on an amorphous silicon (a-Si) substrate. The polyamic acid composition according to the present invention can express the most desirable adhesion to the amorphous silicon substrate by a third component having a benzophenone structure.

Description

Polyamic acid composition for manufacturing a display substrate and a method for manufacturing a display substrate using the same {Polyamic Acid Composition for Display Substrate and Method for Manufacturing Display Substrate by Using the Same}

The present invention relates to a polyamic acid composition for manufacturing a display substrate and a method for producing a display substrate using the same.

Display devices are rapidly developing around flat panel displays (FPDs), which are large in size, thin, and lightweight. Such flat panel displays include liquid crystal displays (LCDs), organic light emitting displays (OLEDs), and electrophoretic devices.

Recently, in order to further expand the applications and uses of such flat panel displays, flexible displays using flexible substrates have been developed. Such displays are mainly applied to mobile devices such as smart phones and tablet PCs, and their application fields are expanding.

The display substrate constituting the flexible display may be manufactured by a process of forming a TFTs on Plastic (TOP) device structure on a flexible substrate. However, since the process is performed at a high temperature of 300 ° C. or higher, specifically 400 ° C. or higher, a polyimide-based material having flexible properties with the highest level of heat resistance and mechanical properties among organic polymer materials is preferably used as a flexible substrate. have.

Typically, the display substrate is coated with (i) a solution of polyamic acid, a precursor of polyimide, on a sacrificial layer made of amorphous silicon (a-Si) to form a polyimide resin, which is a flexible substrate, and (ii) Performing the process of forming the thin film transistor element structure on a flexible substrate made of a mid resin, and (iii) when such a process is completed, by removing the sacrificial layer from the flexible substrate using a laser having a predetermined wavelength. Can be.

Various process variables can be combined to produce a display substrate having a desired quality, but one particularly important is that the flexible substrate, polyimide resin, is bonded to the sacrificial layer at an appropriate level.

The above-described appropriate level means that the adhesion state and shape of the polyimide resin and the sacrificial layer are firmly maintained in the process of forming the thin film transistor element structure on the polyimide resin, and the sacrificial layer is removed from the polyimide resin when the sacrificial layer is removed after this step. It means the level at which the layer can be easily peeled off.

If the adhesion of the polyimide resin to the sacrificial layer is poor, serious damage may occur when the polyimide resin or the sacrificial layer is dropped in the process of forming a thin film transistor on the polyimide resin.

On the contrary, when the adhesive force exceeds a predetermined level, the polyimide resin and a part of the sacrificial layer remain in a bonded state in the process of peeling the sacrificial layer with a laser, or ash derived from the sacrificial layer is applied to the polyimide resin. It may be glued. As a result, the polyimide resin may be damaged during the peeling process, and the quality of the display substrate obtained by peeling may be degraded. In addition, if the energy of the laser is amplified in order to completely peel off the sacrificial layer maintaining a strong adhesion state, the polyimide resin or the thin film transistor element structure may be damaged or destroyed.

Therefore, there is a need for a novel polyimide-based material capable of solving the above technical problems.

It is an object of the present invention to provide a novel polyamic acid composition which can solve the conventional problems recognized above at once.

According to an aspect of the present invention, the polyamic acid composition may be in a state of being cured on an amorphous silicon substrate, that is, when converted into a polyimide resin, the adhesion force with the amorphous silicon may be 0.05 to 0.1 N / cm.

This adhesive strength is maintained while the adhesion state and form of the polyimide resin and the amorphous silicon, which is a sacrificial layer, is firmly formed in the process of forming a thin film transistor element structure on the polyimide resin derived from the polyamic acid composition, but the sacrificial layer is removed after this process. In particular, the sacrificial layer can be easily peeled from the polyimide resin, which is particularly preferable.

By this aspect, the above problem can be solved, and the present invention provides a specific embodiment for its implementation.

In one embodiment, the present invention,

Organic solvents; And

A polyamic acid composition comprising a polyamic acid prepared by polymerizing an aromatic dianhydride monomer and an aromatic diamine monomer,

The aromatic dianhydride monomer includes a first component having a biphenyl structure, a second component having one benzene ring, and a third component having a benzophenone structure,

The aromatic diamine-based monomer comprises a diamine component having one benzene ring in excess of 50 mol% relative to its total moles,

The polyamic acid composition, in a state of being cured on an amorphous silicon (a-Si) substrate, provides a polyamic acid composition having an adhesion force of 0.05 to 0.1 N / cm with the amorphous silicon.

In one embodiment, the invention is a method of making a display substrate using a polyamic acid composition,

Hereinafter, embodiments of the invention will be described in more detail in the order of the "polyamic acid composition" and "method for producing a display substrate" according to the present invention.

Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the configuration of the embodiments described herein is only one of the most preferred embodiments of the present invention and does not represent all of the technical idea of the present invention, various equivalents and modifications that may be substituted for them at the time of the present application It should be understood that examples may exist.

As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise. As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

As used herein, "dianhydrides" are intended to include precursors or derivatives thereof, which may technically not be dianhydrides, but nevertheless will react with diamines to form polyamic acids. This polyamic acid can be converted back to polyimide.

As used herein, "diamine" is intended to include precursors or derivatives thereof, which may not technically be diamines, but will nevertheless react with dianhydrides to form polyamic acid, which polyamic The acid can be converted back to polyimide.

Where an amount, concentration, or other value or parameter is given herein as an enumeration of ranges, preferred ranges, or preferred upper and preferred lower values, any pair of upper range limits, whether or not a range is disclosed separately, or It is to be understood that this disclosure specifically discloses all ranges that may be formed to the desired value and any lower range limit or desired value. When a range of numerical values is referred to herein, unless otherwise stated, for example, unless there is a limiting term such as greater than or less than, the range is intended to include the endpoint value and all integers and fractions within that range. It is intended that the scope of the invention not be limited to the particular values mentioned when defining the range.

Polyamic acid composition

The polyamic acid composition according to the present invention,

Organic solvents; And

The aromatic dianhydride monomer and the aromatic diamine monomer may include a polyamic acid prepared by polymerization.

The aromatic dianhydride monomer may include a first component having a biphenyl structure, a second component having one benzene ring, and a third component having a benzophenone structure.

The aromatic diamine-based monomer may include more than 50 mol% of the diamine component having one benzene ring with respect to the total number of moles thereof.

The amount of the first component may be 50 mol% to 70 mol% based on the total number of moles of the aromatic dianhydride monomer.

The amount of the second component may be 20 mol% to 40 mol% based on the total number of moles of the aromatic dianhydride monomer.

The amount of the third component may be greater than 1 mol% to less than 7 mol% based on the total number of moles of the aromatic dianhydride monomer.

Such a polyamic acid composition, in a state of being cured on an amorphous silicon substrate, may have an adhesion force of 0.05 to 0.1 N / cm with the amorphous silicon.

The polyamic acid composition may also be cured by heat treatment to form a polyimide resin. In detail, the polyamic acid composition may be heat-treated at 20 ° C. to 550 ° C., specifically 20 ° C. to 500 ° C. to prepare a polyimide resin, and such polyimide resin may have excellent physical properties as described below.

-Coefficient of thermal expansion up to 8 ppm / ℃

-Glass transition temperature above 490 ℃

-Pyrolysis temperature above 555 ℃

-Tensile strength over 350 MPa

-More than 20% elongation

-60% or more transmittance

In this regard, in the case of the polyamic acid composition of the present invention and polyimide resin produced thereby, which can satisfy all of the above physical properties, it can be preferably used as a material of a display substrate.

The polyimide resin and the polyamic acid composition implementing the same are both polyimide resins that can express all of these physical properties, which will be described in more detail below through non-limiting examples.

<Adhesive force>

In general, the amorphous silicon substrate may be used in the manufacture of a display substrate, without limitation, in particular, may be used as a sacrificial layer that is adhered to and removed from the flexible substrate in the manufacture of the display substrate. In this case, the polyamic acid composition of the present invention may be cured on the amorphous silicon substrate to form a polyimide resin, and the polyimide resin may be preferably used as a flexible substrate.

As the sacrificial layer, an amorphous silicon substrate exists in a state of being bonded to a polyimide resin in a process of forming a thin film transistor (TFT) device structure. After this process, when the laser is irradiated to the amorphous silicon substrate, the amorphous silicon substrate and the polyimide resin The adhesive state of the can be released and can be peeled off each other.

It should be noted, however, that if the adhesive force is slightly outside the range described in the present invention, the polyimide resin or the thin film transistor element formed on the polyimide resin may be greatly damaged.

For example, a slight exceeding of the adhesion may lead to a non-desirable embodiment in which at least a portion of the amorphous silicon substrate remains adhered to the polyimide resin despite the treatment of the amorphous silicon substrate using a laser. . In such an embodiment, the portion of the polyimide resin maintained in the adhesive state may be broken by the amorphous silicon substrate.

In addition, ash derived from an amorphous silicon substrate may be adhered to the polyimide resin.

In another aspect, it may be considered to induce delamination of the amorphous silicon substrate using a higher energy laser, but in this case, the high energy of the polyimide resin and the thin film transistor element structure having a thickness in the range of nanometer to micrometer The influence of the laser can cause their damage, for example, decomposition, deformation and breakage of the resin and / or transistor elements. In addition, high-energy lasers can produce relatively more ash derived from amorphous silicon substrates, which can act as foreign material and degrade, for example, the quality of transistor devices.

When the adhesion force is slightly lower than that of the polyimide resin and the amorphous silicon substrate, the adhesion between the polyimide resin and the amorphous silicon substrate is hardly maintained at a high temperature of about 300 ° C. or higher, specifically 400 ° C. or higher. It can cause the problem of peeling naturally.

This is the main reason why it is difficult to use the polyimide resin as a flexible substrate because the process of forming the thin film transistor element structure on the polyimide resin is performed at a high temperature of about 300 ° C or higher. Under relatively low adhesion compared to the scope of the present invention, at least a part of the polyimide resin may be peeled off to cause an excited state, or the peeled part may be curled to form curls, in which case the process may not proceed. Do.

In summary, it is important that the adhesive force between the polyimide resin and the amorphous silicon substrate is extremely limited and in the most preferred range, and the present invention provides such a preferred range as described above. In addition, the polyamic acid composition of the present invention can express the adhesive strength in the above range to the amorphous silicon substrate in the cured state.

Furthermore, in the polyamic acid composition of the present invention, in the state of being cured on an amorphous silicon substrate, the adhesive force measured after laser irradiation may be 0.01 N / cm or less. The adhesion force after the laser irradiation may be at a level at which the adhesion state between the amorphous silicon substrate and the amorphous silicon substrate may not be substantially maintained, and thus, for example, after the process of forming the thin film transistor device structure, The polyimide resin can be easily peeled from the amorphous silicon substrate, and its form can be maintained intact.

The present invention provides a method of curing a polyamic acid composition to form a polyimide resin and testing adhesion in this state.

The test method,

The polyamic acid composition was coated on an amorphous silicon (a-Si) substrate having a width of 1 cm * 10 cm and heat-treated to form a polyimide resin thin film having a thickness of about 10 μm to 20 μm, specifically 13 μm to 17 μm. In the state, a tape having a width of 1 cm is attached to the end of the polyimide resin and the force required for the measurement is measured while peeling the polyimide resin from the substrate using the tape.

As a method of measuring adhesion after laser treatment, the following method may be used:

The polyamic acid composition is coated on an amorphous silicon substrate having a width of 1 cm * 10 cm and heat-treated to form a polyimide resin thin film having a thickness of about 10 μm to 20 μm, specifically 13 μm to 17 μm. After irradiating an amorphous silicon substrate with a laser having a wavelength of 308 nm, a tape of 1 cm in width is attached to the end of the polyimide resin, and the tape is used to peel the polyimide resin from the substrate and the force required thereto is measured.

The use of the third component having a benzophenone structure may be the main reason that the adhesive force of the cured polyamic acid composition may satisfy the limited and most preferred range described in the present invention.

Specifically, in the polyamic acid composition of the present invention, the polymer chain of the polyamic acid may include a benzophenone structure by a third component having a benzophenone structure, and the benzophenone structure is a polyimide in which the polyamic acid polymer chain is converted. It can also be retained in the polymer chain. The benzophenone structure can improve adhesion through interaction with a polar functional group such as a hydroxyl group present on the surface of the amorphous silicon substrate, and only when the structure of the third component and its content satisfy the scope of the present invention. Adhesion with an adhesion object, such as an amorphous silicon substrate, may play a major role in the expression at a desired level.

Adhesion of the conventional polyimide resin is in the extremely low side, for example, it can have a low adhesion of less than 0.05 N / cm to the amorphous silicon substrate. This may be attributed to the fact that the polyimide resin includes a weak surface boundary layer (WBL) at the contact interface with the amorphous silicon substrate. Although the surface-vulnerable layer has various forms, one of them may be in an excited form, at least a part of the polyimide resin does not support the amorphous silicon substrate at the contact interface.

The excited form may be generated by, for example, a weak attraction force at the interface between the polyimide resin and the amorphous silicon substrate, or by moisture and / or an organic solvent volatilized when the polyamic acid composition is converted into a polyimide resin. have.

The third component may improve the adhesion level of the polyimide resin by interacting with the polar functional group of the benzophenone structure present in the amorphous silicon substrate.

In addition, the benzophenone structure of the third component may be advantageous to facilitate the volatilization of water and / or organic solvents at the initial point of conversion of the polyamic acid composition to the polyimide resin, so that the third component may be converted to polyimide. The resin can advantageously act to suppress the phenomenon of being lifted from the amorphous silicon substrate.

As a result, the third component may advantageously serve to minimize the formation of such a surface vulnerable layer in the polyimide resin, and may be related to the polyimide resin having a desired level of adhesion.

However, considering only the above-described advantages, it is not preferable to use the third component in a predetermined amount or more, since the adhesion of the polyimide resin to the amorphous silicon substrate can be significantly increased to easily exceed 0.1 N / cm.

In addition, the use of the third component can excessively increase the glass transition temperature drop and the coefficient of thermal expansion of the polyimide resin, which is preferable for the production of display substrates produced by chemical / physical interaction with inorganic materials, for example. Not

Therefore, the content of the third component may be in the range of the adhesion force of the polyimide resin is in the range of 0.05 to 0.1 N / cm, and should be selected particularly carefully in the range that the glass transition temperature and the coefficient of thermal expansion are not implemented in a non-preferred embodiment. do.

In one example, the content of the third component relative to the total moles of the aromatic dianhydride monomer may be greater than 1 mol% to less than 7 mol%, and in detail, may be 2 mol% to 5 mol%. And, more specifically, 3 mol to 5 mol%.

In the present invention, the third component having a benzophenone structure may be 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA).

<Other physical properties>

The third component having a benzophenone structure may be a relatively flexible monomer in terms of molecular structure since a pair of benzene rings may be bent based on a carbonyl group, and the flexible monomer may be a coefficient of thermal expansion of a polyimide resin derived from a polyamic acid composition. Can help increase

However, the thermal expansion coefficient of most inorganic materials, including amorphous silicon, is smaller than 9 ppm / ° C., specifically 8 ppm / ° C. or less, so that the polyimide resin that can adhere to the inorganic material is too large thermal expansion. Having a modulus can be quite undesirable in terms of dimensional stability.

The coefficient of thermal expansion can generally be reduced when using monomers rigid in terms of molecular structure. Rigidity in terms of molecular structure may mean a molecular structure in which the main chain between the diamine group or the carboxyl group is composed of one benzene ring, and thus the main chain is hardly bent.

The second component may thus be a component having one benzene ring, specifically pyromellitic dianhydride (PMDA), wherein the polyimide resin derived from the polyamic acid composition of the present invention has a low coefficient of thermal expansion. Can work.

However, when only the pyromellitic dianhydride having such a rigid structure is used in combination with the third component, the coefficient of thermal expansion of the polyimide film may be excessively lower than 6 ppm / ° C, specifically 1 ppm / ° C or less. In addition, the polyimide resin converted from the polyamic acid composition may exhibit brittle brittle characteristics and may have a relatively low elongation.

In the present invention, it should be noted that the aromatic dianhydride monomer further includes a first component together with the second component and the third component.

The first component having a biphenyl structure is not a rigid molecular structure compared to the second component but may be regarded as a more flexible structure and a rigider molecular structure for the third component, and consequently, a molecular structure for rigidity or flexibility. In an aspect, the first component may be a material between the second component and the third component.

The polyamic acid composition of the present invention may have an elongation of 20% or more due to the first component, and such elongation may preferably work in a process of forming a thin film transistor device structure, for example.

In addition, as the first component, the second component, and the third component are combined, the polyimide resin derived from the polyamic acid composition of the present invention is 8 ppm / ° C. or less, specifically 7.7 ppm / ° C. or less, and more specifically, It can have an appropriate coefficient of thermal expansion of 6 ppm / ° C. to 7 ppm / ° C., has an excellent glass transition temperature of 490 ° C. or higher, in particular a glass transition temperature of 500 ° C.-550 ° C., and a tensile strength of 350 MPa or more, in detail. It may have a tensile strength of 370 MPa or more.

It is particularly important for the first component and the second component to be combined in a desired content for the above to be realized, and thus the present invention provides the preferred content of the first component and the second component.

In one example, the content of the first component relative to the total number of moles of the aromatic dianhydride monomers is 50 mol% to 70 mol%, specifically 55 mol% to 65 mol%, more specifically 57 mol% To 62 mol%, in particular from 58 mol% to 60 mol%.

The content of the second component is 20 mol% to 40 mol%, specifically 30 mol% to 40 mol%, more specifically 32 mol% to 38 mol%, based on the total number of moles of the aromatic dianhydride monomer. Specifically, it may be 35 mol% to 38 mol%.

When the content of the first component is less than the above range and the content of the second component is above the above range, the elongation and coefficient of thermal expansion of the polyimide resin are too low, and the resin has a non-preferable property with brittle characteristics. It can lead to an aspect. When the content of the first component exceeds the above range and the content of the second component below the above range, the coefficient of thermal expansion of the polyimide resin may increase rapidly and the glass transition temperature may decrease, which is not preferable.

The aromatic dianhydride monomer may further include some other dianhydride component in addition to the first to third components described above.

Such dianhydride components include, but are not limited to, 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (a-BPDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone- 3,4,3 ', 4'-tetracarboxylic dianhydride (DSDA), bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3 ', 4'- benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl Methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimelitic monoester acid anhydride), p-biphenylenebis (tri Melittic monoester acid anhydride), m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3', 4'-tetracar Cyclolic dianhydride, 1,3- Bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy ) Biphenyl dianhydride, 2,2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1, 4,5,8-naphthalenetetracarboxylic dianhydride, 4,4 '-(2,2-hexafluoroisopropylidene) diphthalic acid dianhydride, etc. are mentioned.

Meanwhile, the diamine component having one benzene ring may have a molecular structure in which the main chain between the diamine groups is composed of one benzene ring and the main chain is hard to be bent.

As described above, the thermal expansion coefficient of most inorganic materials, including amorphous silicon, is relatively small, and the polyimide resin applied thereto preferably has a thermal expansion coefficient similar to that of the inorganic material.

The diamine component having one benzene ring may be preferable in terms of lowering the coefficient of thermal expansion. In another aspect, the diamine component may also advantageously improve the glass transition temperature of the polyimide resin. In addition, an aspect in which the diamine component can offset the increase in coefficient of thermal expansion due to the relatively low content of the second component used may also be recognized as a preferable factor.

The diamine component having one benzene ring includes 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene and 3, A component including at least one selected from 5-diaminobenzoic acid may be selected as the diamine component.

Of these, 1,4-diaminobenzene is a diamine component having one benzene ring, which is advantageous for improving tensile strength and which can be advantageously used in combination with the pyromellitic dianhydride to induce a coefficient of thermal expansion to a desired level. It may be desirable.

The aromatic diamine-based monomer may comprise a diamine component having one benzene ring in an amount greater than 50 mol%, in particular 60 mol% or more, in particular 70 mol% to 100 mol%, based on the total number of moles thereof. .

When the content of the diamine component exceeds the above range, the elongation and coefficient of thermal expansion of the polyimide resin may be too low, leading to a non-preferred embodiment in which the resin has brittle characteristics. When the content of the diamine component is less than the above range, it is not preferable because the thermal expansion coefficient of the polyimide resin is rapidly increased and the glass transition temperature may be lowered.

The aromatic diamine monomer may further include some other dianhydride component in addition to the diamine component described above.

Such diamine components include, but are not limited to, diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxydianiline, ODA), 3,4'-diaminodiphenyl ether, and 4,4 '. -Diaminodiphenylmethane (or methylenedianiline, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2 , 2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4, 4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4'-diaminobenz Anilide, 3,3'-dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine , 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'- Diaminodiphenylsulfa Id, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3 ' -Diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone , 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) propane, 2,2 -Bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenylsulfoxide, 3,4'-diaminodiphenylsulfoxide, 4,4'-diaminodi Phenylsulfoxide 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4- Amino phenyl) benzene, 1,3-bis (4-aminophenoxy) benzene (or TPE-R), 1,4-bis (3-aminophenoxy) benne Zen (or TPE-Q) 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3, 3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) benzene , 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4 -Aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4 ' -Bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4- Aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl Ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) phenyl] ketone, bis [4 -(3-aminophenoxy) phenyl] ketone, bis [4- (4-amino phenoxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] sulfide, bis [3- (4-amino Phenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3-aminophenoxy) phenyl] Sulfone, bis [3- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [3 -(3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-amino Phenoxy) phenyl] methane, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] prop Board, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 2,2-bis [3 -(3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] -1,1, 1,3,3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane and 2, 2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane is mentioned.

As described above, the polyamic acid composition according to the present invention has a desirable adhesive force for implementing the display substrate due to the third component, and in addition, as the first component and the second component are combined, various characteristics required for the polyimide are It may be at an appropriate level.

<Additive>

The polyamic acid composition according to the present invention may further include at least one of a silane coupling agent and a silicone surfactant.

The silane coupling agent is a part of which is bonded to the amic acid group of the polyamic acid composition or the imide group of the polyimide resin to which the amic acid group is converted, and the other part is an inorganic material, such as a silicon-based material, for example, amorphous silicon It may be combined with oxygen or silicon present in the substrate.

By this action, the silane coupling agent can increase the adhesion of the polyimide resin derived from the curing of the polyamic acid composition within the range of 0.05 to 0.1 N / cm.

However, since the excessive use of the silane coupling agent may cause a decrease in the physical properties of the polyimide resin derived from the polyamic acid composition, it may be preferable to be used in an extremely limited content.

As an example for this, the silane coupling agent is 0.01 to 0.05% by weight, specifically 0.01 to 0.03% by weight, particularly specifically 0.018 to 0.022% by weight, based on the weight of the polyamic acid solids of the polyamic acid composition. Can be included.

Silane-based coupling agents that may be preferably included in the polyamic acid composition of the present invention include, but are not limited to, 3-aminopropyltrimethoxysilane (APTMS), aminopropyltriethoxysilane, 3- (2-aminoethylamino) propyl-dimethoxymethylsilane (3- (2-aminoethylamino) propyl-dimethoxymethylsilane), 3-glycidoxypropyldimethoxymethylsilane and 2- (3,4 -Epoxy cyclohexyl) trimethoxysilane (2- (3,4-epoxycyclohexyl) trimethoxysilane) may include one or more selected from the group consisting of, and particularly preferably, including an amine group, of the polyamic acid composition 3-aminopropyltrimethoxysilane, aminopropyltriethoxysilane and 3- (2-aminoethylamino) propyl-dimethoxy which are easily bonded to an amic acid group or an imide group of a polyimide resin converted to an amic acid group It may include one or more selected from the group consisting of tilsilane, and most preferably may be 3-aminopropyltrimethoxysilane, which may be advantageous in preventing physical degradation of the polyimide resin derived from the polyamic acid composition. .

For example, when the silicone-based surfactant is applied to an inorganic substrate or the like, the silicone-based surfactant may be preferably used to make the polyamic acid composition having fluidity spread well on the substrate to form a uniform thickness.

However, when the surfactant is included in an excessive amount, at least a portion of the polyamic acid composition may aggregate to make film formation difficult, and may cause a decrease in physical properties of the polyimide resin resulting from curing of the polyamic acid composition. On the contrary, a small amount of the surfactant is not preferable because it does not help the above-mentioned film-related advantages.

The preferred amount of surfactant may be from 0.001 to 0.02% by weight, in particular from 0.005 to 0.015% by weight, in particular from 0.008 to 0.012% by weight, based on the weight of the polyamic acid solids of the polyamic acid composition.

The type of the surfactant is not particularly limited, but silicone-based surfactants may be preferable. The silicone-based surfactants can be easily obtained commercially, for example, BYK-378 manufactured by BYK may be used as the silicone-based surfactant. However, the above examples are intended to help the practice of the invention, the surfactant that can be used in the present invention is not limited to the above examples.

The polyamic acid composition also includes at least one selected from acetic anhydride (AA), propion acid anhydride, and lactic acid anhydride, quinoline, isoquinoline, β-picolin (BP) and pyridine. It may further include a curing accelerator.

Such a curing accelerator may help to obtain a desired polyimide resin by promoting a ring-closure reaction through dehydration action on the polyamic acid after forming the polyamic acid composition and then converting it to a polyimide resin.

The curing accelerator may be included in an amount of 0.05 to 20 moles with respect to 1 mole of the amic acid group in the polyamic acid.

When the curing accelerator is less than the above range, the degree of promotion of dehydration and / or ring closure reaction is insufficient, which may cause cracks in the converted polyimide resin, and may cause a decrease in strength of the polyimide resin. Can be.

In addition, when the amount of the curing accelerator is more than the above range, the imidization may proceed excessively rapidly. In this case, it is difficult to cast the polyamic acid composition into a thin film, or the converted polyimide resin may exhibit brittle characteristics. It can be undesirable.

The polyamic acid composition may further include a filler for the purpose of improving various properties of the polyimide resin, such as the slidability, thermal conductivity, and loop hardness of the polyimide resin derived from the polyamic acid composition.

The filler is not particularly limited, but preferred examples thereof include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.

The average particle diameter of the said filler is not specifically limited, It can determine according to the polyimide resin characteristic to modify and the kind of filler to add. In one example, the average particle diameter of the filler may be from 0.05 μm to 100 μm, in particular from 0.1 μm to 75 μm, more preferably from 0.1 μm to 50 μm, in particular from 0.1 μm to 25 μm.

If the average particle diameter is less than this range, the modifying effect is less likely to appear. If the average particle diameter is higher than this range, the filler may significantly impair the surface property of the polyimide resin or cause a decrease in its mechanical properties.

In addition, it is not specifically limited also about the addition amount of a filler, It can determine by the polyimide resin characteristic to be modified, filler particle diameter, etc ..

In one example, the amount of the filler added is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, more preferably 0.02 to 80 parts by weight, based on 100 parts by weight of the polyamic acid composition.

If the amount of filler added is less than this range, the effect of modification by the filler is less likely to appear, and if it exceeds this range, the mechanical properties of the polyimide resin may be greatly reduced. The addition method of a filler is not specifically limited, Of course, any well-known method can be used.

<Method for producing polyamic acid composition>

For example, a method of preparing a polyamic acid constituting the polyamic acid composition,

(1) a method in which the entire amount of the diamine monomer is placed in an organic solvent, and then the dianhydride monomer is added so as to be substantially equimolar to the diamine monomer and polymerized;

(2) a method in which the entire amount of the dianhydride monomer is placed in an organic solvent, and then the diamine monomer is added so as to be substantially equimolar to the dianhydride monomer and polymerized;

(3) After putting some components of the diamine monomer in the organic solvent, and mixed some components of the dianhydride monomer in the ratio of about 95 mol% to 105 mol% with respect to the reaction component, and then the remaining diamine monomer component Adding and subsequent addition of the remaining dianhydride monomer component to polymerize the diamine monomer and the dianhydride monomer so as to be substantially equimolar;

(4) After the dianhydride monomer is added to the organic solvent, some components of the diamine compound are mixed at a ratio of 95 mol% to 105 mol with respect to the reaction component, and then another dianhydride monomer component is added and continuously Adding the remaining diamine monomer component and polymerizing the diamine monomer and the dianhydride monomer to be substantially equimolar; And

(5) Some diamine monomer component and some dianhydride monomer component are reacted to an excess in an organic solvent to form a first polymer, and some diamine monomer component and some dianhydride in another organic solvent. A method of mixing the first monomer and the second polymer and then completing the polymerization by reacting the lide monomer component in an excess amount to form a second polymer, wherein the diamine monomer is used when the first polymer is formed. When the component is excessive, the dianhydride monomer component is excessive in the second polymer, and when the dianhydride monomer component is excessive in the first polymer, the diamine monomer component is excessive in the second polymer. 1, the second polymer is mixed with the total diamine monomer component and dianhydride monomer properties used in these reactions To ensure that the mall, etc. The substantially include a method of polymerization and the like.

However, the above method is an example to assist in the practice of the present invention, and the scope of the present invention is not limited thereto, and any known method may be used.

The organic solvent is not particularly limited as long as it is a solvent in which the polyamic acid can be dissolved, but as an example, the organic solvent may be an aprotic polar solvent.

Non-limiting examples of the aprotic polar solvent include amide solvents such as N, N'-dimethylformamide (DMF) and N, N'-dimethylacetamide (DMAc), p-chlorophenol, o-chloro Phenol solvents such as phenol, N-methyl-pyrrolidone (NMP), gamma butyrolactone (GBL), and Diglyme (Diglyme), and the like. These may be used alone or in combination of two or more thereof.

In some cases, the solubility of the polyamic acid may be adjusted by using auxiliary solvents such as toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol and water.

In one example, the organic solvents which can be particularly preferably used for preparing the polyamic acid composition of the present invention may be N-methyl-pyrrolidone, N, N'-dimethylformamide and N, N'-dimethylacetamide. .

When the polyamic acid composition thus prepared has a polyamic acid solid content of 15%, the viscosity measured at 23 ° C. is 3,000 cP to 7,000 cP, specifically 3,500 cP to 6,500 cP, in particular 4,000 cP to 5,500 cP Can be.

If the viscosity of the polyamic acid composition exceeds the above range, the dispenser nozzle used in the application process may be blocked by the polyamic acid composition, and if it is below the above range, the dispenser nozzle is applied to a desired thickness due to the excessive flowability of the polyamic acid composition. This can cause process problems that are difficult to do. In addition, the low viscosity below the above range may lead to a decrease in the adhesion of the polyimide resin formed by converting the polyamic acid composition.

Moreover, even if the viscosity of a polyamic-acid composition exceeds the said range, since application | coating to a desired form may be difficult because of high viscosity, it is not preferable.

Manufacturing Method of Display Substrate Using Polyamic Acid Composition

The present invention provides a method of manufacturing a display substrate using the polyamic acid composition of the foregoing embodiments.

Specifically, the method,

Applying the polyamic acid composition on an amorphous silicon substrate;

First heat treating the polyamic acid composition at 20 ° C. to 40 ° C .;

Second heat treatment of the polyamic acid composition at 40 ° C. to 200 ° C .; And

The polyamic acid composition may include a third heat treatment at 200 ℃ to 500 ℃.

Through the first heat treatment, the second heat treatment, and the third heat treatment step, the polyamic acid composition generates a polyimide resin including an imide group in which the amic acid group of the polyamic acid is ring-closed and dehydrated, and the organic solvent is volatilized and cured. When the third heat treatment is completed, the polyimide resin may be cured and bonded on the amorphous silicon substrate.

In one specific example, applying the polyamic acid composition on the amorphous silicon substrate, the thickness of the polyimide resin produced after the polyamic acid composition is cured is 0.5 ㎛ to 20 ㎛, specifically 2 ㎛ to The polyamic acid composition may be applied such that it is 18 μm, in particular 2 to 5 μm.

In one specific example, the first heat treatment, the second heat treatment and the third heat treatment step, each independently, at least two variable temperature increase rate selected from the range of 3 ℃ / min to 7 ℃ / min, or in the above range It can be carried out at one constant temperature increase rate selected.

Manufacturing method according to the invention,

Forming a thin film transistor (TFT) on the polyimide resin, and

Irradiating the amorphous silicon substrate with a laser for a predetermined time, and removing the amorphous silicon substrate from the polyimide resin,

It may be 0.01 N / cm or less between the polyimide resin and the amorphous silicon substrate measured after the laser irradiation.

The adhesion force after the laser irradiation may be at a level at which the adhesion state between the amorphous silicon substrate and the amorphous silicon substrate may not be substantially maintained, and thus, for example, after the process of forming the thin film transistor device structure, The polyimide resin can be easily peeled from the amorphous silicon substrate, and its form can be maintained intact.

In the step of removing the amorphous silicon substrate, the laser may be performed by a laser lift off (LLO) method.

The energy density (E / D) of the laser may be 180 mJ / cm ² or less, preferably 150 mJ / cm ² or less.

As described above, the polyamic acid composition according to the present invention can express the most preferable adhesion to the amorphous silicon substrate by the third component having a benzophenone structure.

The polyamic acid composition according to the present invention is also a polyimide resin in which various physical properties required for the manufacture of a display substrate are intrinsic to a suitable level, for example, by a combination of a dianhydride monomer and a diamine monomer containing a specific component. Can be implemented.

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these embodiments are only presented as an example of the invention, whereby the scope of the invention is not determined.

<Example 1>

In a 40 ° C. reactor filled with NMP, PPD as an aromatic dianhydride monomer, BPDA (first component), PMDA (second component), BTDA (third component), and aromatic diamine monomer, at a molar ratio shown in Table 1 below. The polyamic acid was polymerized by addition and stirring for about 30 minutes.

To this, the following materials were added, followed by a aging process for about 2 hours to prepare the final polyamic acid composition. At this time, the viscosity of the polyamic acid composition was about 5,100 cP.

Silane coupling agent: 0.02% by weight of 3-aminopropyltrimethoxysilane (based on the weight of polyamic acid solids)

-Silicone surfactant: 0.01 wt% of BYK 'BYK-378' (based on the weight of polyamic acid solids)

-Additive: 10% by weight of isoquinoline (based on the weight of polyamic acid solids)

<Example 2>

The viscosity was about 5,000 cP in the same manner as in Example 1 except that the molar ratios of BPDA (first component), PMDA (second component) and BTDA (third component) were changed to the molar ratios shown in Table 1 below. A polyamic acid composition was prepared.

<Example 3>

The viscosity was about 5,100 cP in the same manner as in Example 1, except that the molar ratio of BPDA (first component), PMDA (second component), and BTDA (third component) was changed to the molar ratio shown in Table 1 below. A polyamic acid composition was prepared.

<Example 4>

The viscosity was about 4,800 cP in the same manner as in Example 1 except that the molar ratio of BPDA (first component), PMDA (second component), and BTDA (third component) was changed to the molar ratio shown in Table 1 below. A polyamic acid composition was prepared.

Comparative Example 1

BTDA (third component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of BPDA (first component) and PMDA (second component) was added to the molar ratio shown in Table 1 below. In the same manner as in Example 1, a polyamic acid composition having a viscosity of about 4,800 cP was prepared.

Comparative Example 2

BTDA (third component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of BPDA (first component) and PMDA (second component) was added to the molar ratio shown in Table 1 below. In the same manner as in Example 1, a polyamic acid composition having a viscosity of about 5,300 cP was prepared.

Comparative Example 3

BTDA (third component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of BPDA (first component) and PMDA (second component) was added to the molar ratio shown in Table 1 below. In the same manner as in Example 1, a polyamic acid composition having a viscosity of about 4,750 cP was prepared.

<Comparative Example 4>

BTDA (third component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of BPDA (first component) and PMDA (second component) was added to the molar ratio shown in Table 1 below. In the same manner as in Example 1, a polyamic acid composition having a viscosity of about 4,950 cP was prepared.

Comparative Example 5

The viscosity was about 5,100 cP in the same manner as in Example 1, except that the molar ratio of BPDA (first component), PMDA (second component), and BTDA (third component) was changed to the molar ratio shown in Table 1 below. A polyamic acid composition was prepared.

Comparative Example 6

Polyamic acid of about 5,100 cP in the same manner as in Example 1, except that the molar ratio of BPDA (first component), PMDA (second component), and BTDA (third component) was changed to the molar ratio shown in Table 1 below. The composition was prepared.

Comparative Example 7

PMDA (second component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of BPDA (first component) and BTDA (third component) was added to the molar ratio shown in Table 1 below. In the same manner as in Example 1, a polyamic acid composition having a viscosity of about 5,300 cP was prepared.

<Comparative Example 8>

Except BPDA (first component) was excluded as a component of the aromatic dianhydride monomer, except that the molar ratio of PMDA (second component) and BTDA (third component) was changed to the molar ratio shown in Table 1 and added. In the same manner as in Example 1 to prepare a polyamic acid composition having a viscosity of about 4,850 cP.

Furtherance Molar ratio Dianhydride monomers Diamine monomer Dianhydride monomers Diamine monomer First ingredient Second ingredient Third ingredient First ingredient Second ingredient Third ingredient Example 1 BPDA PMDA BTDA PPD 60 38 2 100 Example 2 BPDA PMDA BTDA PPD 60 35 5 100 Example 3 BPDA PMDA BTDA PPD 55 40 5 100 Example 4 BPDA PMDA BTDA PPD 65 32 3 100 Comparative Example 1 BPDA PMDA - PPD 60 40 - 100 Comparative Example 2 BPDA PMDA - PPD 70 30 - 100 Comparative Example 3 BPDA PMDA - PPD 80 20 - 100 Comparative Example 4 BPDA PMDA - PPD 50 50 - 100 Comparative Example 5 BPDA PMDA BTDA PPD 60 39 One 100 Comparative Example 6 BPDA PMDA BTDA PPD 60 33 7 100 Comparative Example 7 BPDA - BTDA PPD 95 - 5 100 Comparative Example 8 - PMDA BTDA PPD - 95 5 100

Experimental Example 1: Adhesion Test of Polyimide Resin

The polyamic acid composition prepared in Examples 1 to 4 and Comparative Examples 1 to 8 was cast on an amorphous silicon substrate having a width of 1 cm x 10 cm at 30 μm and dried at a temperature range of 20 ° C. to 460 ° C., whereby the average thickness A laminate was prepared in which a polyimide resin and an amorphous silicon substrate in the form of a thin film having a thickness of about 15 to 17 μm were bonded.

The first adhesive force (before laser treatment), curl test, and second adhesive force (after laser treatment) of the polyimide resin were evaluated for the laminate thus produced using the following method.

First adhesive force: A tape of 1 cm in width is attached to the end of the polyimide resin, and the tape is used to peel the polyimide resin from the substrate and the force required for this is measured.

-Curl Test: The prepared laminate was heat treated at a temperature of about 400 ° C. for about 1 hour, and then it was checked whether curls were generated at the corners of the polyimide resin on the amorphous silicon substrate.

-Second adhesive force: After irradiating an amorphous silicon substrate with a laser of 308 nm wavelength of 150 mJ / cm ² , a tape of 1 cm in width is attached to the end of the polyimide resin and the polyimide resin is removed from the substrate using this tape. Peel off and measure the force required for it.

First adhesion
(N / cm) Curls occur
(O, X) Second adhesion
(N / cm) Example 1 0.07 X 0.01 or less Example 2 0.08 X 0.01 or less Example 3 0.07 X 0.01 or less Example 4 0.07 X 0.01 or less Comparative Example 1 0.03 O 0.01 or less Comparative Example 2 0.03 O 0.01 or less Comparative Example 3 0.03 O 0.01 or less Comparative Example 4 0.03 O 0.01 or less Comparative Example 5 0.03 O 0.01 or less Comparative Example 6 0.12 X 0.05 Comparative Example 7 0.03 O 0.01 or less Comparative Example 8 0.03 O 0.01 or less

Experimental Example 2: Physical Properties Test of Polyimide Resin

After applying the polyamic acid composition prepared in Examples 1 to 4 and Comparative Examples 1 to 8 in the form of a thin film on a stainless steel support and heat-treated at a temperature range of 20 ℃ to 350 ℃, and then peeled from the support to the average thickness, respectively, A polyimide resin in the form of a film of about 15 to 17 μm was prepared.

The physical properties of the polyimide resin thus prepared were tested in the following manner, and the results are shown in Table 3 below.

(1) coefficient of thermal expansion (CTE)

The coefficient of thermal expansion was measured in the range of 100 to 350 ° C using TMA.

(2) Glass transition temperature (T _g )

For glass transition temperature, TMA was used to determine the loss modulus and storage modulus of each polyimide resin, and the inflection point was measured by the glass transition temperature in the tangent graph.

(3) Pyrolysis temperature (T _d )

Using the thermogravimetric analyzer (TG-DTA2000), the temperature was measured when the initial weight of the polyimide resin decreased by 1% while the temperature was raised to a temperature increase rate of 10 ° C / min in nitrogen.

(4) tensile strength

Tensile strength was measured by the method presented in KS6518.

(5) elongation

Elongation was measured by the method given in ASTM D1708.

(6) transmittance

The transmittance of 550 nm wavelength was measured in Hunter's ColorQuesetXE model by the method shown in ASTM D1003 in the visible region.

CTE
(ppm / ℃) T _g
(℃) T _d
(℃) The tensile strength
(MPa) Elongation
(%) Transmittance
(%) Example 1 6.2 507 567 385 23.8 60.8 Example 2 6.4 509 563 388 23.4 61.0 Example 3 6.7 506 561 382 22.7 60.7 Example 4 7.7 495 559 374 24.8 61.3 Comparative Example 1 6.3 508 566 382 23.8 60.7 Comparative Example 2 11.8 481 569 347 27.9 62.1 Comparative Example 3 14.1 435 565 324 34.8 65.7 Comparative Example 4 5.8 521 556 398 15.2 57.1 Comparative Example 5 6.1 508 563 378 22.8 60.4 Comparative Example 6 9.5 489 561 382 17.5 61.8 Comparative Example 7 18.8 385 533 315 45.4 70.8 Comparative Example 8 Film Crumb (Not measurable)

From the results of Experimental Example 1, the Example exhibited an appropriate level of adhesion to the amorphous silicon substrate, that is, the first adhesive force belonging to 0.05 to 0.1 N / cm.

Advantages of the first adhesive force in the above range can be confirmed indirectly through the occurrence of curl. According to Table 2, the Example did not generate any curl even if the heat treatment for a predetermined time at a high temperature of 400 ℃.

If the adhesive force is low, the adhesion state of the polyimide resin and the amorphous silicon substrate is released at a high temperature of 400 ℃ to generate curl curling the end of the polyimide resin inward. In fact, most of the comparative examples showed lower first adhesive force than the examples, and all curls were generated.

This result suggests that an adhesive force of at least 0.05 N / cm is required for the TFT process performed at a high temperature, and it can be seen that the embodiment according to the present invention expresses a desirable adhesive force for the TFT process. In another aspect, the examples exhibited extremely minor adhesion (second adhesion) after laser treatment for removal of the amorphous silicon substrate, from which the amorphous silicon substrate was removed from the polyimide resin once the first adhesion was met. It can be expected that this can be peeled off well.

On the other hand, Comparative Examples 1 to 5, 7 and 8 can confirm that the first adhesive force is out of the range of 0.05 to 0.1 N / cm. Due to this low first adhesive force, the comparative examples may be expected to generate curl at a high temperature, and may be unsuitable for manufacturing a display substrate requiring a high temperature process.

Comparative Example 6 is a case where the first adhesive force is excessive, in particular, the second adhesive force after the laser treatment can also be confirmed that the level is considerably high, which is unlikely to peel off the amorphous silicon substrate from the polyimide resin after laser irradiation unlike the embodiment Imply that

The results of Experimental Example 2 shows that the polyimide resin implemented according to the present invention satisfies all of the various properties required for the manufacture of the display substrate, and in connection with the results of Experimental Example 1, all of the examples, Together expresses the desired level of adhesion.

On the contrary, it can be seen that the comparative example is not suitable for use as a display substrate because at least one characteristic is not satisfied with poor adhesive force.

In particular, Comparative Example 8 relates to a polyamic acid composition prepared without using the first dianhydride component of the present invention, and filming did not proceed to such an extent that physical properties cannot be measured.

Accordingly, it can be seen from the results of Table 3 that the monomer combination and the combination ratio of the present invention are effective for the implementation of the polyamic acid composition.

Although described above with reference to embodiments of the present invention, those skilled in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (17)

Organic solvents; And
A polyamic acid composition comprising a polyamic acid prepared by polymerizing an aromatic dianhydride monomer and an aromatic diamine monomer,
The aromatic dianhydride monomer includes a first component having a biphenyl structure, a second component having one benzene ring, and a third component having a benzophenone structure,
The amount of the first component is 50 mol% to 70 mol%, the content of the second component is 20 mol% to 40 mol%, and the content of the third component is 1 based on the total number of moles of the aromatic dianhydride monomer. Greater than mole% to less than 7 mole%,
The aromatic diamine-based monomer comprises a diamine component having one benzene ring in excess of 50 mol% relative to its total moles,
The polyamic acid composition, in the state of curing on an amorphous silicon (a-Si) substrate, the adhesive force with the amorphous silicon is 0.05 to 0.1 N / cm polyamic acid composition. The method of claim 1,
A polyamic acid composition having an adhesive force of 0.01 N / cm or less measured after laser irradiation in a state of being cured on an amorphous silicon substrate. delete The method of claim 1,
The first component is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 2,3,3', 4'-biphenyltetracarboxylic dianhydride (a- BPDA) at least one polyamic acid composition selected from the group consisting of. The method of claim 1,
Wherein said second component is pyromellitic dianhydride (PMDA). The method of claim 1,
Wherein said third component is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA). The method of claim 1,
The diamine component having one benzene ring includes 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene and 3, At least one polyamic acid composition selected from the group consisting of 5-diaminobenzoic acid. The method of claim 1,
The diamine component having one benzene ring is 1,4-diaminobenzene. The method of claim 1,
A polyamic acid composition further comprising at least one of a silane coupling agent and a silicone surfactant. The method of claim 9,
The silane coupling agent,
0.01 to 0.05% by weight, based on the weight of polyamic acid solids of the polyamic acid composition;
3-aminopropyltrimethoxysilane ((3-Aminopropyl) trimethoxysilane (APTMS), aminopropyltriethoxysilane, 3- (2-aminoethylamino) propyl-dimethoxymethylsilane (3- (2- aminoethylamino) propyl-dimethoxymethylsilane, 3-glycidoxypropyldimethoxymethylsilane and 2- (3,4-epoxycyclohexyl) trimethoxysilane (2- (3,4-epoxycyclohexyl) trimethoxysilane) Polyamic acid composition comprising one or more selected from the group consisting of. The method of claim 9,
The silicone-based surfactant is a polyamic acid composition containing 0.001 to 0.02% by weight based on the weight of the polyamic acid solids of the polyamic acid composition. The method of claim 1,
A polyamic acid composition having a viscosity measured at 23 ° C. of 3,000 to 7,000 cP when the polyamic acid solid content of the polyamic acid composition is 15%. The method of claim 1,
The polyimide resin prepared by heat treatment of the polyamic acid composition at 20 ℃ to 400 ℃,
Glass transition temperature is over 490 ℃,
Pyrolysis temperature is above 555 ℃,
A polyamic acid composition having a thermal expansion coefficient of 8 ppm / ° C. or less. The method of claim 13,
The polyimide resin has a tensile strength of 350 MPa or more, an elongation of 20% or more, and a transmittance of 60% or more. A method of manufacturing a display substrate using the polyamic acid composition according to claim 1,
Applying the polyamic acid composition on an amorphous silicon substrate;
First heat treating the polyamic acid composition at 20 ° C. to 40 ° C .;
Second heat treatment of the polyamic acid composition at 40 ° C. to 200 ° C .; And
A third heat treatment of the polyamic acid composition at 200 ° C. to 500 ° C.,
Through the first heat treatment, the second heat treatment, and the third heat treatment step, the polyamic acid composition generates a polyimide resin including an imide group in which the amic acid group of the polyamic acid is ring-closed and dehydrated, and the organic solvent is volatilized and cured. ,
When the third heat treatment is completed, the polyimide resin is cured on the amorphous silicon substrate and bonded. The method of claim 15,
The first heat treatment, the second heat treatment, and the third heat treatment step may each independently include two or more variable heating rates selected from a range of 3 ° C./min to 7 ° C./min, or one constant selected from the range. Manufacturing method performed at a temperature rising rate. The method of claim 15,
Forming a thin film transistor (TFT) on the polyimide resin, and
Irradiating the amorphous silicon substrate with a laser for a predetermined time to remove the amorphous silicon substrate from the polyimide resin,
A method for producing a non-bonded polyimide resin and an amorphous silicon substrate measured after the laser irradiation is 0.01 N / cm or less.