KR20210131696A - Polyamide-based optical laminated film and method of preparing the same - Google Patents

Abstract

The present invention relates to a polyamide-based optical laminated film and a method for preparing the same. According to the present invention, provided are a polyamide-based optical laminated film capable of showing drastically low curl values while having excellent mechanical properties and optical properties, and a method for preparing the same.

Description

Polyamide-based optical laminated film and manufacturing method thereof

The present invention relates to a polyamide-based optical laminated film and a manufacturing method thereof.

Aromatic polyimide resins are mostly polymers having an amorphous structure, and exhibit excellent heat resistance, chemical resistance, electrical properties, and dimensional stability due to a rigid chain structure. Such polyimide resins are widely used as electrical/electronic materials.

However, the polyimide resin has a dark brown color due to the formation of a charge transfer complex (CTC) of Pi-electrons in the imide chain, making it difficult to secure transparency. In addition, the polyimide film has a disadvantage that the surface is easily scratched and scratch resistance is very weak.

In order to improve the limitations of such polyimide resins, studies on polyamide-based resins having amide groups introduced therein are being actively conducted. The amide structure induces intermolecular or intramolecular hydrogen bonding, enabling improvement of scratch resistance through interactions such as hydrogen bonding.

In general, in order to improve the hardness and scratch resistance of the optical film, an additional process of providing a hard coating layer on the resin laminate is performed. However, curl of the resin laminate may occur due to heating or the like during the additional process of applying the hard coating layer.

An object of the present invention is to provide a polyamide-based optical laminated film capable of exhibiting a remarkably low curl value while having excellent mechanical properties and optical properties.

An object of the present invention is to provide a manufacturing method capable of preventing or minimizing the occurrence of curls during manufacturing of the polyamide-based optical laminate film including a hard coating layer.

Hereinafter, a polyamide-based optical laminated film and a manufacturing method thereof according to an embodiment of the present invention will be described in detail.

Unless explicitly stated herein, terminology is for the purpose of referring to specific embodiments only, and is not intended to limit the present invention.

As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite.

As used herein, the meaning of “comprising” specifies a particular characteristic, region, integer, step, operation, element and/or component, and other specific characteristic, region, integer, step, operation, element, component, and/or group. It does not exclude the existence or addition of

In the present specification, terms including an ordinal number such as 'first' and 'second' are used for the purpose of distinguishing one element from another element, and are not limited by the ordinal number. For example, within the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

I. Manufacturing method of polyamide-based optical laminated film

According to one embodiment of the invention,

Isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) in a molar ratio range of 1:0.01 to 1:100 by melt-kneading the coagulated acyl chloride complex is copolymerized with an aromatic diamine compound to prepare a polyamide resin step, and

forming a laminate in which two or more resin coating layers including the polyamide resin are laminated;

Each of the polyamide resins included in the two or more resin coating layers have different molar ratio values,

The two or more resin coating layers are laminated so that the molar ratio value of each resin coating layer increases sequentially in the thickness direction of the laminate,

A method for producing a polyamide-based optical laminated film is provided.

The present inventors have conducted continuous research on a method for manufacturing an optical laminated film for forming a laminate in which two or more resin coating layers including a polyamide resin are laminated.

As a result, it was confirmed that after forming an artificial curl in the laminate, the curl can be offset by providing a hard coating layer on any one surface of the laminate.

In particular, in forming the laminate, two or more resin coating layers are formed by applying a polyamide resin copolymerized with the acyl chloride complex and an aromatic diamine compound, and the molar ratio of IPC: TPC of the acyl chloride complex is adjusted. It was confirmed that artificial curls can be formed in the laminate.

For example, two or more resin coating layers formed by the above method may exhibit different coefficients of thermal expansion (CTE) due to a difference in the molar ratio of each resin coating layer. In addition, the difference in the coefficient of thermal expansion enables the formation of artificial curls in the laminate.

(1) preparing a polyamide resin

A step of preparing a polyamide resin by copolymerizing an acyl chloride complex solidified by melt-kneading isophthaloyl chloride (hereinafter referred to as IPC) and terephthaloyl chloride (hereinafter referred to as TPC) with an aromatic diamine compound is performed.

The TPC having a linear molecular structure maintains a constant chain packing and alignment within the polymer, enabling improvement of surface hardness and mechanical properties of the polyamide film. IPC having a curved molecular structure interferes with chain packing and alignment in the polymer, increasing the amorphous area in the polyamide resin, and enabling the improvement of optical properties and bending strength of the polyamide film.

However, since IPC and TPC show different aspects in solubility and reactivity due to chemical structural differences, even if they are simultaneously added to the polymerization reaction, amide repeating units derived from TPC are overwhelmingly formed and long blocks are formed. There is a limit in that crystallinity of the polyamide resin is increased by forming, and it is difficult to secure transparency.

In addition, when synthesizing a conventional polyamide resin, IPC and TPC are dissolved in a solvent and then reacted with an aromatic diamine compound in a solution state. There was a limit in that the molecular weight of the amide resin decreased.

Accordingly, in the invention of the above embodiment, the IPC and TPC are not simply physically mixed, but are melt-kneaded at a temperature higher than the melting point of IPC and TPC to form an acyl chloride complex, and it is copolymerized with an aromatic diamine compound to obtain a relatively uniform A polymerization reaction may be induced.

Preferably, depending on the application of the acyl chloride complex, the polyamide resin may have a main chain of a structure in which an amide repeating unit derived from IPC and an amide repeating unit derived from TPC are alternately bonded to each other.

According to an embodiment, in forming the acyl chloride complex, IPC and TPC may be melt-kneaded at a molar ratio of 1:0.01 to 1:100.

As a non-limiting example, the molar ratio values of IPC and TPC (IPC:TPC) are 1:0.01, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3 , 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1 :9.5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65 , 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, or 1:100.

In the present specification, the large or small value of the molar ratio may be determined by the number of moles of TPC based on the number of moles of IPC within the molar ratio range. For example, the relatively large value of the molar ratio means that the number of moles of TPC within the molar ratio range is relatively large. In addition, when the molar ratio value is relatively small, it means that the number of moles of TPC is relatively small within the molar ratio range. For example, the molar ratio value (IPC:TPC) of 1:1 is smaller than the molar ratio value of 1:10.

In order to prevent deterioration of physical properties such as hardness and tensile strength of the polyamide resin, the molar ratio (IPC:TPC) is preferably 1:0.01 or more. However, if the TPC is applied in excess, the polyamide resin may become opaque, resulting in poor optical properties. Therefore, the molar ratio value (IPC:TPC) is preferably 1:100 or less.

In addition, the molar ratio value may be variously adjusted within the above range in consideration of properties to be imparted to each resin coating layer including the polyamide resin and properties to be imparted to a laminate including the resin coating layers. This will be described in more detail in the step of forming the laminate.

According to one embodiment, the acyl chloride composite solidified by melt-kneading IPC and TPC, forming a mixture obtained by melt-kneading IPC and TPC at a temperature of 90 ° C. or higher; And it may be prepared by a method comprising the step of cooling the mixture.

The melt-kneading means mixing IPC and TPC at a temperature above their respective melting points. IPC has a melting point of 43 °C to 44 °C, TPC has a melting point of 81.3 °C to 83 °C. Therefore, when the IPC and TPC are mixed at a temperature of 90° C. or higher, or 90° C. to 120° C., or 95° C. to 110° C., or 100° C. to 110° C., melt kneading may proceed.

By cooling (solidifying) the melt-kneaded mixture at a temperature lower than the melting point of IPC and TPC (for example, 5 ° C or less, or -10 ° C to 5 ° C, or -5 ° C to 5 ° C), the acyl A chloride complex (solid powder) can be obtained.

Optionally, a grinding step for forming the acyl chloride complex into uniform particles may be further performed. The acyl chloride complex obtained after the pulverization may have an average particle diameter of 1 mm to 10 mm.

A polyamide resin may be provided by copolymerizing the acyl chloride complex with an aromatic diamine compound.

The copolymerization may be performed under an inert gas atmosphere at a temperature of minus 25 °C to 25 °C, or minus 25 °C to 0 °C.

As the aromatic diamine compound, compounds known to be applicable to the formation of polyamide resins in the art to which the present invention pertains may be used without particular limitation. For example, the aromatic diamine compound is 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine), 2 ,2'-dimethyl-4,4'-diaminobenzidine (2,2'-dimethyl-4,4'-diaminobenzidine), 4,4'-diaminodiphenyl sulfone (4,4'-diaminodiphenyl sulfone), 4,4'-(9-fluorenylidene)dianiline (4,4'-(9-fluorenylidene)dianiline), bis(4-(4-aminophenoxy)phenyl)sulfone (bis(4-(4) -aminophenoxy)phenyl)sulfone), 2,2',5,5'-tetrachlorobenzidine (2,2',5,5'-tetrachlorobenzidine), 2,7-diaminofluorene (2,7-diaminofluorene) , 4,4-diaminooctafluorobiphenyl (4,4-diaminooctafluorobiphenyl), m-phenylenediamine (m-phenylenediamine), p-phenylenediamine (p-phenylenediamine), 4,4'-oxydianiline ( 4,4'-oxydianiline), 2,2'-dimethyl-4,4'-diaminobiphenyl (2,2'-dimethyl-4,4'-diaminobiphenyl), 2,2-bis[4-(4) -Aminophenoxy) phenyl] propane (2,2-bis [4- (4-aminophenoxy) phenyl] propane), 1,3-bis (4-aminophenoxy) benzene (1,3-bis (4-aminophenoxy) ) benzene), m-xylylenediamine, p-xylylenediamine, and 4,4'-diaminobenzanilide selected from the group consisting of It may be one or more compounds.

The copolymerization may include dissolving the aromatic diamine compound in an organic solvent to prepare a diamine solution; and adding the acyl chloride complex to the diamine solution.

Examples of the organic solvent include N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, and N,N-dimethyl Propionamide, 3-methoxy-N,N-dimethylpropionamide, dimethylsulfoxide, acetone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, tetrahydrofuran, chloroform, gamma- At least one solvent selected from the group consisting of butyrolactone, ethyl lactate, methyl 3-methoxypropionate, methyl isobutyl ketone, toluene, xylene, methanol, and ethanol may be used.

The acyl chloride complex powder reacts with the aromatic diamine compound dissolved in the diamine solution. Accordingly, it is possible to minimize the deterioration of the acyl chloride complex due to moisture or the hybridization with the solvent.

Preferably, the polyamide resin is 300,000 g/mol or more, or 400,000 g/mol or more, or 500,000 g/mol or more, or 300,000 g/mol to 1,000,000 g/mol, or 400,000 g/mol to 1,000,000 g/mol , or from 500,000 g/mol to 1,000,000 g/mol, or from 400,000 g/mol to 800,000 g/mol, or from 400,000 g/mol to 600,000 g/mol, or from 450,000 g/mol to 550,000 g/mol, Mw ) can have

In order to secure mechanical properties such as flexibility and pencil hardness, the weight average molecular weight of the polyamide resin is preferably 300,000 g/mol or more.

In the present specification, the weight average molecular weight (Mw) may be measured using an Agilent PL-GPC 220 instrument equipped with a 300 mm-long PolarGel MIXED-L column (Polymer Laboratories). The measurement temperature is 65° C., tetrahydrofuran or dimethylformamide is used as a solvent, and the flow rate is measured at a rate of 1 mL/min. Prepare the sample to a concentration of 10 mg/10 mL, then feed in an amount of 100 μL. The Mw and Mn values are derived with reference to a calibration curve formed using polystyrene standards. The molecular weight (g/mol) of polystyrene standards is 580/ 3,940/ 8,450/ 31,400/ 70,950/ 316,500/ 956,000/ 4,230,000.

(2) forming a laminate

The step of forming a laminate in which two or more resin coating layers including the polyamide resin are laminated is performed.

The resin coating layers include the polyamide resin or a cured product thereof. The cured product means a material obtained through the curing process of the polyamide resin.

The resin coating layers may be formed by a conventional method such as a dry method and a wet method using the polyamide resin. For example, the resin coating layer may be obtained by coating a solution containing the polyamide resin on an arbitrary support (or a previously formed resin coating layer) to form a film, and evaporating a solvent from the film to dry it.

According to an embodiment, two or more of the resin coating layers are sequentially stacked to form a laminate. It may be preferable for the laminate to include two, three, or four resin coating layers for balancing optical properties and mechanical properties.

The thickness of the laminate may be adjusted within the range of 0.01 μm to 1000 μm. Each resin coating layer included in the laminate may be formed to have the same or different thickness in consideration of the overall thickness of the laminate.

Preferably, the thickness of the laminate is from 1 µm to 1000 µm, alternatively from 5 µm to 800 µm, alternatively from 10 µm to 500 µm, alternatively from 10 µm to 400 µm, alternatively from 20 µm to 300 µm, alternatively from 20 µm to 200 µm μm, or 50 μm to 100 μm.

In particular, in forming the laminate, the respective polyamide resins included in the two or more resin coating layers have different molar ratio values.

By giving different molar ratio values to the polyamide resin included in each resin coating layer, different coefficients of thermal expansion (CTE) may be expressed in each of the resin coating layers.

According to the research results of the present inventors, it was confirmed that the coefficient of thermal expansion (CTE) of the polyamide resin increased as the number of moles of IPC increased (ie, the number of moles of TPC decreased) in the molar ratio of IPC:TPC.

That is, the resin coating layer including the polyamide resin having a relatively large molar ratio value exhibits a relatively small coefficient of thermal expansion. In addition, the resin coating layer including the polyamide resin having a relatively small molar ratio has a relatively large coefficient of thermal expansion.

For example, the resin coating layer formed using the polyamide resin having the molar ratio (IPC:TPC) of 1:1 is formed using the polyamide resin having the molar ratio (IPC:TPC) of 1:10. It has a higher coefficient of thermal expansion than that of the resin coating layer.

Accordingly, by giving different molar ratio values to each of the polyamide resins included in the two or more resin coating layers, and adjusting the stacking order, artificial curls may be formed in the laminate.

Preferably, the forming of the laminate may be performed such that the molar ratio value of the polyamide resin included in the two or more resin coating layers sequentially increases in the thickness direction of the laminate.

As a non-limiting example, the resin coating layer having the largest molar ratio value in the laminate is 1:1 or more, or 1:4 or more, or 1:4 to 1:100, or 1:4 to 1:10. It may include a polyamide resin having a molar ratio value.

As a non-limiting example, the resin coating layer having the largest molar ratio value in the laminate is 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1: 7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1: 10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, Molar ratio values of 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, or 1:100 (IPC :TPC).

In addition, the remaining resin coating layer(s) other than the resin coating layer having the largest molar ratio value in the laminate may be stacked in an order satisfying the above-described conditions. Here, the molar ratio value and the difference of each of the remaining resin coating layer(s) are not particularly limited.

Referring to FIG. 1 , when forming a laminate including the two resin coating layers stacked sequentially, forming a first resin coating layer 10 ; and forming a second resin coating layer 20 on the first resin coating layer 10 .

For example, when forming a laminate including the two resin coating layers stacked sequentially, forming a first resin coating layer 10 including a polyamide resin having the molar ratio value of 1:4 or more; and forming a second resin coating layer 2 including a polyamide resin having the molar ratio value of less than 1:4 on the first resin coating layer 10 .

In this case, the first resin coating layer 10 has a smaller coefficient of thermal expansion (CTE) than that of the second resin coating layer 20 as it has a larger molar ratio value than that of the second resin coating layer 20 .

Due to the difference in the coefficient of thermal expansion between the first and second resin coating layers, an artificial curl may be formed in the laminate in the direction of the second resin coating layer 20 . And, by forming the hard coating layer 30 on the first resin coating layer 10, the curl can be naturally offset.

In order to provide proper curl to the laminate, the molar ratio value (M ₁ ) given to the first resin coating layer is 1:4 to 1:10, and is provided to the second resin coating layer The molar ratio value (M ₂ ) may be preferably 1:1 or more and less than 1:4.

(3) forming a hard coating layer

According to an embodiment of the present invention, the method of manufacturing the polyamide-based optical laminated film may further include forming a hard coating layer on any one surface of the laminate.

The hard coating layer may be formed on any one surface capable of offsetting an artificial curl imparted to the laminate.

For example, the hard coating layer may be formed on the resin coating layer having the largest molar ratio value in the laminate.

Preferably, in the step of forming the laminate, the molar ratio value of the polyamide resin included in the two or more resin coating layers is sequentially increased in the thickness direction of the laminate; The hard coating layer is formed on the resin coating layer including the polyamide resin having the largest molar ratio.

The hard coating layer may be formed to a thickness of 0.1 μm to 100 μm. Preferably, the thickness of the hard coating layer may be 1 μm to 100 μm, or 1 μm to 80 μm, or 5 μm to 50 μm, or 5 μm to 20 μm.

As long as the hard coating layer is a material well known in the art to which the present invention pertains, it may be applied without particular limitation.

For example, the hard coating layer may be formed using a composition including a binder that is a photocurable resin and inorganic or organic particles dispersed in the binder.

The photocurable resin is a polymer of a photocurable compound. The photocurable compound may be a polyfunctional (meth)acrylate-based monomer or oligomer. The number of (meth)acrylate-based functional groups may be 2 to 10, or 2 to 8, or 2 to 7, which may be advantageous in terms of securing physical properties of the hard coating layer.

The photocurable compound is pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol hepta (meth) Acrylates, tripentaerythritol hepta(meth)acrylate, torylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate, and trimethylolpropane polyethoxy tri(meth)acrylic It may be one or more compounds selected from the group consisting of lactate.

The inorganic particle may be, for example, a metal atom such as silica, aluminum, titanium, or zinc, or an oxide thereof, or a nitride thereof. The inorganic particles may have an average particle diameter of 100 nm or less, or 5 nm to 100 nm. As the organic particles, polymer particles having an average particle diameter of 10 nm to 100 μm may be used.

Optionally, the step of forming a coating layer including at least one resin selected from the group consisting of a polyamideimide resin and a polyimide resin on a surface different from the surface of the laminate on which the hard coating layer is formed may be further performed. .

Taking FIG. 1 as an example, the step of forming a coating layer including at least one resin selected from the group consisting of a polyamideimide resin and a polyimide resin on the second resin coating layer 20 may be further performed.

The formation of the additional coating layer may be performed in the same manner as in the formation of the laminate, except that polyamideimide resin, polyimide resin, or the like is used.

II. Polyamide-based optical laminated film

According to another embodiment of the invention,

a laminate in which two or more resin coating layers including a polyamide resin are sequentially stacked;

The polyamide resin is obtained by copolymerizing an acyl chloride complex obtained by melt-kneading isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) at a molar ratio of 1:0.01 to 1:100 and coagulated with an aromatic diamine compound. will,

Each of the polyamide resins included in the two or more resin coating layers have different molar ratio values,

The two or more resin coating layers are laminated so that the molar ratio value of each resin coating layer increases sequentially in the thickness direction of the laminate,

A polyamide-based optical laminated film is provided.

The polyamide-based optical laminated film includes a laminate in which two or more resin coating layers including a polyamide resin are sequentially laminated.

In addition, the polyamide-based optical laminate film may further include a hard coating layer laminated on any one surface of the laminate.

The hard coating layer may be formed on any one surface capable of offsetting an artificial curl imparted to the laminate.

2 as an example, the polyamide-based optical laminated film is a laminate including a first resin coating layer 10 and a second resin coating layer 20 laminated sequentially, and a first resin coating layer of the laminate ( 10) may include a hard coating layer 30 laminated thereon.

Each polyamide resin included in the two or more resin coating layers is an acyl chloride complex solidified by melt-kneading isophthaloyl chloride (hereinafter referred to as IPC) and terephthaloyl chloride (hereinafter referred to as TPC) with an aromatic diamine compound it is copolymerized.

As the polyamide resin is obtained by applying the acyl chloride complex, it may have a main chain of a structure in which an amide repeating unit derived from IPC and an amide repeating unit derived from TPC are alternately bonded to each other.

For specific details regarding the formation of the polyamide resin, see <I. It is replaced with the content described in the item> Manufacturing method of polyamide-type optical laminated|multilayer film.

The resin coating layers include the polyamide resin or a cured product thereof. The cured product means a material obtained through the curing process of the polyamide resin.

The laminate includes two or more of the resin coating layers sequentially stacked. Preferably, the laminate may include two, three, or four resin coating layers for balancing optical properties and mechanical properties.

The thickness of the laminate may be adjusted within the range of 0.01 μm to 1000 μm. Each resin coating layer included in the laminate may be formed to have the same or different thickness in consideration of the overall thickness of the laminate.

Preferably, the thickness of the laminate is from 1 µm to 1000 µm, alternatively from 5 µm to 800 µm, alternatively from 10 µm to 500 µm, alternatively from 10 µm to 400 µm, alternatively from 20 µm to 300 µm, alternatively from 20 µm to 200 µm μm, or 50 μm to 100 μm.

In particular, in the laminate, each of the polyamide resins included in the two or more resin coating layers have different molar ratio values (IPC:TPC).

By giving different molar ratio values to the polyamide resin included in each resin coating layer, different coefficients of thermal expansion (CTE) may be expressed in each of the resin coating layers.

Preferably, one resin coating layer adjacent to the hard coating layer among the two or more resin coating layers included in the laminate may have a higher molar ratio value than the other resin coating layer(s).

Preferably, the laminate may be laminated such that the molar ratio value of the polyamide resin included in the two or more resin coating layers sequentially increases in a thickness direction of the laminate. The hard coating layer is formed on the resin coating layer including the polyamide resin having the largest molar ratio.

Preferably, the laminate may be laminated so that the coefficient of thermal expansion (CTE) of each resin coating layer sequentially decreases in the thickness direction of the laminate. In addition, one resin coating layer adjacent to the hard coating layer among the two or more resin coating layers may have a smaller coefficient of thermal expansion than the other resin coating layer(s).

As a non-limiting example, the resin coating layer having the largest molar ratio value in the laminate is 1:1 or more, or 1:4 or more, or 1:4 to 1:100, or 1:4 to 1:10. It may include a polyamide resin having a molar ratio value.

As a non-limiting example, the resin coating layer having the largest molar ratio value in the laminate is 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1: 7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1: 10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, Molar ratio values of 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, or 1:100 (IPC :TPC).

In addition, the remaining resin coating layer(s) other than the resin coating layer having the largest molar ratio value in the laminate may be stacked in an order satisfying the above-described conditions. Here, the molar ratio value and the difference of each of the remaining resin coating layer(s) are not particularly limited.

As illustrated in FIG. 2 , the polyamide-based optical laminated film is

a first resin coating layer 10 comprising a polyamide resin having the molar ratio value in the range of 1:4 to 1:10;

a second resin coating layer 20 laminated on any one surface of the first resin coating layer 10 and including a polyamide resin having the molar ratio value in the range of 1:1 or more and less than 1:4; and

The hard coating layer 30 laminated on the other side of the first resin coating layer 10

may include.

The laminate may be laminated so that the coefficient of thermal expansion (CTE) of each resin coating layer sequentially decreases in the thickness direction of the laminate.

Each of the two or more resin coating layers may have a coefficient of thermal expansion (CTE) of 0 to 100 ppm/°C.

As a non-limiting example, the first resin coating layer 10 has a coefficient of thermal expansion (CTE) of 5.0 to 6.0 ppm/°C, or 5.2 to 6.0 ppm/°C, or 5.2 to 5.8 ppm/°C, or 5.2 to 5.6 ppm/°C. can have

And, the second resin coating layer 20 is 6.5 to 20.0 ppm / ℃, or 7.0 to 20.0 ppm / ℃, or 7.0 to 19.5 ppm / ℃, or 7.5 to 19.5 ppm / ℃, or 7.5 to 19.0 ppm / ℃, Alternatively, it may have a coefficient of thermal expansion (CTE) of 8.0 to 19.0 ppm/°C, or 8.0 to 18.5 ppm/°C, or 8.5 to 18.5 ppm/°C.

The hard coating layer may be formed on the resin coating layer having the molar ratio greater than that of the remaining resin large coating layer(s) among the two or more resin coating layers.

The hard coating layer may have a thickness of 0.1 μm to 100 μm. Preferably, the thickness of the hard coating layer may be 1 μm to 100 μm, or 1 μm to 80 μm, or 5 μm to 50 μm, or 5 μm to 20 μm.

Optionally, the polyamide-based optical laminated film includes a coating layer comprising at least one resin selected from the group consisting of a polyamideimide resin and a polyimide resin, on a surface different from the surface of the laminate on which the hard coating layer is formed. may include more.

The polyamide-based optical laminated film may have a radius of curvature of curl of the film greater than 30 mm after standing for 30 minutes in an environment of 25° C. and 60% relative humidity. Preferably, the polyamide-based optical laminate film may have a radius of curvature of the curl greater than 30 mm, or greater than or equal to 40 mm.

In this specification, the curl of the film is defined as follows. When a film has a longitudinal direction, let the longitudinal direction be a 1st direction. When the four sides of the film are the same or there is no longitudinal direction, the direction of any side is set as the first direction. It cuts out to 35 mm x 3 mm so that a 1st direction may become a long side, the curvature radius of a long side direction is measured, and it is set as the curvature radius of a 1st direction. Similarly, with respect to the first direction, the directions at intervals of 45° are each long side, and the radius of curvature in the second to fourth directions is measured. Among the curvature radii of the first to fourth directions, the direction having the minimum radius of curvature is set as the curl direction of the film, and the radius of curvature is referred to as the radius of curvature of the curl of the film.

The measurement of the radius of curvature of the curl of the film after standing for 30 minutes in an environment of 25° C. and 60% relative humidity can be performed as follows. The film is cut to 35mm x 3mm. At this time, it cuts out in the 1st - 4th direction used as a 45 degree interval in a long side direction. After standing for 30 minutes in an environment of 25 ℃ and 60% relative humidity, it can be measured according to the standard measurement method A of ISO 18910:2000. The cut radius of curvature in the long side direction (35 mm) is read, and the value in the direction that becomes the smallest value among the curvature radii in the first to fourth directions is defined as the radius of curvature of the curl of the film.

The polyamide-based optical laminate film may have a curl value of 4.0 mm or less, or 3.5 mm or less after standing for 30 minutes in an environment of 25° C. and 60% relative humidity.

The measurement of the curl value of the film may be performed as follows. When measuring the radius of curvature of the curl, the prepared film sample is left in an environment of 25° C. and 60% relative humidity for 30 minutes. After the convex side of the film is set as the lower surface, the maximum height raised from the horizontal plane is measured to be the curl value of the film.

The polyamide-based optical laminated film may be used as a substrate or cover window of a display device. The polyamide-based optical laminate film has high flexibility and bending durability along with high light transmittance and low haze characteristics, and thus may be used as a substrate or cover window of a flexible display device.

According to the present invention, a polyamide-based optical laminated film capable of exhibiting a remarkably low curl value while having excellent mechanical properties and optical properties and a method for manufacturing the same are provided.

1 is a schematic diagram showing a method of manufacturing a polyamide-based optical laminated film according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a polyamide-based optical laminated film according to an embodiment of the present invention.

Hereinafter, preferred embodiments are presented to help the understanding of the invention. However, the following examples are only for illustrating the invention, and do not limit the invention thereto.

[Preparation of polyamide resin and resin solution containing the same]

Preparation Example 1

In a 1000 ml 4-neck round flask (reactor) equipped with a stirrer, nitrogen injector, dropping funnel, and temperature controller, 536.0 g (2.640 mol) of terephthaloyl chloride (TPC, melting point 83° C.) and isophthaloyl chloride (IPC, melting point 44° C.) 134.0 g (0.660 mol) was added, melt-kneaded at 100° C. for 3 hours, and then cooled at 0° C. for 12 hours to obtain acyl chloride composite particles. The acyl chloride composite particles were crushed with a jaw crusher to prepare a powder having an average particle diameter of 5 mm.

228.65 g of N,N-dimethylacetamide (DMAc) while slowly blowing nitrogen into a 1000 ml 4-neck round flask (reactor) equipped with a stirrer, nitrogen injector, dropping funnel, and temperature controller After setting the temperature of the reactor to 0 °C, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine , TFDB) 12.072 g (0.0377 mol) was dissolved. Here, 7.653 g (0.0377 mol) of the acyl chloride complex powder was added and stirred, and the amide formation reaction was carried out at 0° C. for 12 hours. After completion of the reaction, N,N-dimethylacetamide (N,N-dimethylacetamide, DMAc) was added to dilute the solid content to 5% or less, which was precipitated with 1 L of methanol, and the precipitated solid was filtered After drying, the polyamide resin in a solid form was obtained by drying in a vacuum at 100° C. for 6 hours or more.

The polyamide resin was dissolved in DMAc to prepare a resin solution having a solid content of 8% (w/V).

Preparation 2

In the preparation of the acyl chloride complex, the contents of IPC and TPC were changed to 469.0 g (2.310 mol) of terephthaloyl chloride (TPC) and 201.0 g (0.990 mol) of isophthaloyl chloride (IPC). A polyamide resin and a resin solution containing the same were obtained in the same manner as in 1.

Preparation 3

In the preparation of the acyl chloride complex, the contents of IPC and TPC were 402.0 g (1.980 mol) of terephthaloyl chloride (TPC) and 268.0 g (1.320 mol) of isophthaloyl chloride (IPC), except for changing the above Preparation Example A polyamide resin and a resin solution containing the same were obtained in the same manner as in 1.

Preparation 4

In the preparation of the acyl chloride complex, the contents of IPC and TPC were changed to 335.0 g (1.650 mol) of terephthaloyl chloride (TPC) and 335.0 g (1.650 mol) of isophthaloyl chloride (IPC). A polyamide resin and a resin solution containing the same were obtained in the same manner as in 1.

Preparation 5

During polymerization to obtain a polyamide resin, instead of the acyl chloride complex powder of Preparation Example 1, 6.277 g (0.0309 mol) of terephthaloyl chloride (TPC) and 1.378 g (0.0068 mol) of isophthaloyl chloride (IPC) were simultaneously added A polyamide resin and a resin solution including the same were obtained in the same manner as in Preparation Example 1, except that the amide formation reaction was performed.

Preparation 6

During polymerization to obtain a polyamide resin, instead of the acyl chloride complex powder of Preparation Example 1, 6.277 g (0.0309 mol) of terephthaloyl chloride (TPC) was first added, and then isophthaloyl chloride ( IPC), 1.378 g (0.0068 mol) of the polyamide resin and a resin solution including the same were obtained in the same manner as in Preparation Example 1, except that the amide formation reaction was carried out.

Preparation 7

During polymerization to obtain a polyamide resin, 1.378 g (0.0068 mol) of isophthaloyl chloride (IPC) was first added instead of the acyl chloride complex powder of Preparation Example 1, and then terephthaloyl chloride ( TPC) 6.277 g (0.0309 mol) was added to proceed with the amide formation reaction, and a polyamide resin and a resin solution including the same were obtained in the same manner as in Preparation Example 1.

[Production of polyamide-based optical laminated film]

Example 1

The resin solution obtained in Preparation Example 1 was applied on a polyimide base film (UPILEX-75s, UBE), and the thickness of the resin solution was uniformly adjusted using a film applicator. This was dried in a Matiz oven at about 80° C. for 10 minutes to form a first resin coating layer.

The resin solution obtained in Preparation Example 4 was applied on the first resin coating layer, and the thickness of the resin solution was uniformly adjusted using a film applicator. This was dried in a Matiz oven at about 80° C. for 10 minutes to form a second resin coating layer.

Thereafter, after curing at about 250° C. for 30 minutes while flowing nitrogen, it was peeled off from the base film to obtain a laminate having a thickness of about 50 μm.

A composition for hard coating (containing pentaerythritol trimethacrylate) was applied on the first resin coating layer of the laminate, and the thickness was uniformly adjusted using a film applicator. This was photocured and the laminated|multilayer film with a hard-coat layer was obtained.

Example 2

A laminated film was obtained in the same manner as in Example 1, except that the resin solution obtained in Preparation Example 3 was used instead of the resin solution obtained in Preparation Example 4 when the second resin coating layer was formed.

Example 3

A laminated film was obtained in the same manner as in Example 1, except that the resin solution obtained in Preparation Example 2 was used instead of the resin solution obtained in Preparation Example 4 when the second resin coating layer was formed.

Comparative Example 1

A laminated film was obtained in the same manner as in Example 1, except that the resin solution obtained in Preparation Example 1 was used instead of the resin solution obtained in Preparation Example 4 when the second resin coating layer was formed.

Reference Example 1

The resin solution obtained in Preparation Example 1 was applied on a polyimide base film (UPILEX-75s, UBE), and the thickness of the resin solution was uniformly adjusted using a film applicator. This was dried in a Matiz oven at about 80° C. for 10 minutes. Thereafter, after curing at about 250° C. for 30 minutes while flowing nitrogen, it was peeled off from the base film to obtain a film having a thickness of about 50 μm.

Reference Example 2

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 2 was used instead of the resin solution obtained in Preparation Example 1.

Reference Example 3

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 3 was used instead of the resin solution obtained in Preparation Example 1.

Reference Example 4

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 4 was used instead of the resin solution obtained in Preparation Example 1.

Reference Example 5

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 5 was used instead of the resin solution obtained in Preparation Example 1.

Reference Example 6

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 6 was used instead of the resin solution obtained in Preparation Example 1.

Reference Example 7

A film was obtained in the same manner as in Reference Example 1, except that the resin solution obtained in Preparation Example 7 was used instead of the resin solution obtained in Preparation Example 1.

Test Example 1

The coefficient of thermal expansion (CTE) of the films obtained in Reference Examples 1, 2, 3, and 4 was measured, and the results are shown in Table 1 below. The thermal expansion coefficient was measured using a TMA (thermomechanical analyzer) according to the standard measurement method of ISO 11359-2:1999 under a load of 0.05 N, a temperature increase rate of 10 °C/min, and a temperature range of 120 to 180 °C in tension mode mode. carried out

division Reference Example 1 Reference Example 2 Reference Example 3 Reference Example 4 CTE (ppm/℃) 5.5 8.9 13.2 18.3

Test Example 2

The following properties were measured or evaluated for the films obtained in Reference Examples 1, 5, 6, and 7 or the resin solution used for the preparation thereof, and the results are shown in Table 2 below.

(1) Thickness: The thickness of the film was measured using a thickness measuring device.

(2) Yellow index (Y.I.): The yellow index of the film was measured according to ASTM E313 using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

(3) Light transmittance: The total light transmittance of the film was measured using a Shimadzu UV-2600 UV-vis spectrometer. Among the measurement results, transmittance (T, @388nm) for ultraviolet light with a wavelength of 388 nm and transmittance for visible light with a wavelength of 550 nm (T, @550nm) were shown.

(4) Haze: The haze value of the film was measured according to the measurement method of ASTM D1003 using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

(5) Molecular weight and molecular weight distribution (PDI, polydispersity index): The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polyamide resin were measured using gel permeation chromatography (GPC: gel permeation chromatography, manufactured by Waters). was measured, and the molecular weight distribution (PDI) was calculated by dividing the weight average molecular weight by the number average molecular weight. Specifically, using a 600 mm long column with two Polymer Laboratories PLgel MIX-B 300 mm long columns followed by a Waters 2605 instrument (detector: RI), the evaluation temperature was 50 to 75 ° C (about 65 ° C), DMF 100 wt% solvent Using , a flow rate of 1 mL/min, the sample is prepared at a concentration of 1 mg/mL, and then supplied in an amount of 100 μL for 25 minutes, and the molecular weight can be obtained using a calibration curve formed using a polystyrene standard. For the molecular weight of polystyrene standards, 7 types of 3940 / 9600 / 31420 / 113300 / 327300 / 1270000 / 4230000 were used.

(6) Flexibility: The bending strength of the film was evaluated using an MIT-type folding endurance tester. Specifically, a specimen of the film (1 cm * 7 cm) is loaded into a bend strength tester and bent at an angle of 135°, a radius of curvature of 0.8 mm, and a load of 250 g at a speed of 175 rpm on the left and right sides of the specimen until fracture. The number of reciprocating bending cycles was measured.

(7) Relative viscosity: 25±0.2° C. Using a constant temperature reflux system, a solution containing a polyamide resin (solvent: dimethylacetamide (DMAc), solid content 10wt%) was rotated by a non-Newtonian material according to ASTM D 2196 A Brookfield viscometer DV-2T was used as the viscometer test method, and a number of standard solutions having a viscosity range of 5000 cps to 200000 cps were used as a standard material, using Brookfield's silicone oil, spindle LV-4 (64). , was measured at 0.3 to 100 RPM, and the unit was cps (mPa.s).

(8) Pencil hardness: The pencil hardness of the film was measured according to the measurement method of ASTM D3363 using a Pencil Hardness Tester. Specifically, after fixing pencils of various hardnesses to the tester and scratching the film, the degree of scratches on the film was observed with the naked eye or a microscope. The corresponding value was evaluated by the pencil hardness of the film.

The pencil hardness increases in the order of B grade, F grade, and H grade, and the hardness increases as the number increases within the same grade.

division Reference Example 1 Reference Example 5 Reference Example 6 Reference Example 7 Thickness (μm) 50 51 51 50 Y.I. 2.68 8.55 25.10 4.59 T(%) @550nm 88.75 85.63 75.94 87.57 T (%) @388nm 75.3 51.01 31.62 65.04 Haze (%) 0.81 3.43 24.21 1.61 Mw (g/mol) 512000 412000 350000 382000 Flexibility (cycle) 12022 5210 785 4513 PDI 1.84 2.05 2.02 1.98 Viscosity (cps) 110000 54000 24000 28000 pencil hardness 3H 1H F 1H

Test Example 3

The following properties were measured or evaluated for the laminates (without hard coating) and laminated films (with hard coating) obtained in Examples and Comparative Examples. The results for the laminate (without the hard coating) are shown in Table 3 below, and the results for the laminated film (including the hard coating) are shown in Table 4 below.

(1) Thickness: The thickness of the film was measured using a thickness measuring device.

(2) Modulus: The modulus (GPB) was measured according to ISO 527-3 using Universal Testing Systems (Instron® 3360).

(3) Pencil hardness: The pencil hardness of the film was measured according to the measurement method of ASTM D3363 using a Pencil Hardness Tester. Specifically, after fixing pencils of various hardnesses to the tester and scratching the film, the degree of scratches on the film was observed with the naked eye or a microscope. The corresponding value was evaluated by the pencil hardness of the film.

The pencil hardness increases in the order of B grade, F grade, and H grade, and the hardness increases as the number increases within the same grade.

(4) Yellow index (Y.I.): The yellow index of the film was measured according to ASTM E313 using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

(5) The radius of curvature of the curl of the film: The radius of curvature of the curl of the film was measured according to the standard measurement method A of ISO 18910:2000. The obtained film was cut out so that it might become 35 mm x 3 mm in 4 directions so that the machine direction (MD) may be 0 degrees and it might become a 45 degree interval. After the cut out 4 films were left standing for 30 minutes in an environment of 25° C. and 60% relative humidity, the radius of curvature of the curl of the film was read. Further, the amount of curl on the cut long side (35 mm) was read, and the value with the smallest radius of curvature was defined as the radius of curvature of the curl of the film.

(6) Curl of the film: When measuring the radius of curvature of the curl, the prepared film sample was left standing in an environment of 25° C. and 60% relative humidity for 30 minutes. After the convex side of the film was left still on the lower surface, the maximum height lifted from the horizontal plane was measured and it was set as the curl value of the film.

laminate Example 1 Example 2 Example 3 Comparative Example 1 Thickness (μm) 54 54 50 52 Modulus (MPa) 4700 6100 6500 6800 pencil hardness 3H 3H 3H 3H Y.I. 2.6 2.6 2.5 2.5 Curl radius of curvature (mm) 40 50 150 No-curl
(greater than 2000) Curl of film (mm) 4 3 One 0

laminated film Example 1 Example 2 Example 3 Comparative Example 1 Thickness (μm) 64 64 62 62 Modulus (MPa) 6400 6200 6200 5300 pencil hardness 6H 6H 7H 7H Y.I. 2.3 2.3 2.2 2.2 Curl radius of curvature (mm) No-curl
(greater than 2000) 100 40 30 Curl of film (mm) 0 1.5 3.5 4.5

Referring to Tables 3 and 4, it is confirmed that the laminated films according to Examples have excellent mechanical properties and optical properties while exhibiting a remarkably low film curl value of 3.5 mm or less.

10: first resin coating layer
20: second resin coating layer
30: hard coating layer

Claims (14)

Isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) in a molar ratio range of 1:0.01 to 1:100 by melt-kneading the coagulated acyl chloride complex is copolymerized with an aromatic diamine compound to prepare a polyamide resin step, and
forming a laminate in which two or more resin coating layers including the polyamide resin are laminated;
Each of the polyamide resins included in the two or more resin coating layers have different molar ratio values,
The two or more resin coating layers are laminated so that the molar ratio value of each resin coating layer increases sequentially in the thickness direction of the laminate,
A method for producing a polyamide-based optical laminated film.
The method of claim 1,
Forming a hard coating layer on any one surface of the laminate
Further comprising a method for producing a polyamide-based optical laminated film.
3. The method of claim 2,
The method for producing a polyamide-based optical laminated film, wherein the hard coating layer is formed on the resin coating layer having the largest molar ratio value in the laminate.
The method of claim 1,
The acyl chloride complex is formed by melt-kneading isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) at a temperature of 90 ° C. or higher; and cooling the mixture, a method for producing a polyamide-based optical laminated film.
The method of claim 1,
The copolymerization may include dissolving the aromatic diamine compound in an organic solvent to prepare a diamine solution; and adding the acyl chloride complex to the diamine solution.
The method of claim 1,
In the forming of the laminate, the two resin coating layers are laminated, a method of manufacturing a polyamide-based optical laminate film.
7. The method of claim 6,
Forming the laminate comprises:
forming a first resin coating layer comprising a polyamide resin having the molar ratio value in the range of 1:4 to 1:10; and
forming a second resin coating layer comprising a polyamide resin having the molar ratio value in the range of 1:1 or more and less than 1:4 on the first resin coating layer
A method for producing a polyamide-based optical laminated film, comprising:
a laminate in which two or more resin coating layers including a polyamide resin are sequentially stacked;
The polyamide resin is obtained by copolymerizing an acyl chloride complex obtained by melt-kneading isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) at a molar ratio of 1:0.01 to 1:100 and coagulated with an aromatic diamine compound. will,
Each of the polyamide resins included in the two or more resin coating layers have different molar ratio values,
The two or more resin coating layers are laminated so that the molar ratio value of each resin coating layer increases sequentially in the thickness direction of the laminate,
A polyamide-based optical laminated film.
9. The method of claim 8,
The polyamide-based optical laminated film further comprising a hard coating layer formed on any one surface of the laminate.
10. The method of claim 9,
The hard coating layer is formed on the resin coating layer having the largest molar ratio value in the laminate, a polyamide-based optical laminated film.
9. The method of claim 8,
a first resin coating layer comprising a polyamide resin having the molar ratio value in the range of 1:4 to 1:10; and
A second resin coating layer laminated on one side of the first resin coating layer and including a polyamide resin having the molar ratio value in the range of 1:1 or more and less than 1:4
Including, polyamide-based optical laminated film.
9. The method of claim 8,
The laminate is laminated so that the coefficient of thermal expansion (CTE) of each resin coating layer sequentially decreases in the thickness direction of the laminate, a polyamide-based optical laminated film.
9. The method of claim 8,
The at least two resin coating layers each have a coefficient of thermal expansion (CTE) of 0 to 100 ppm/°C, a polyamide-based optical laminate film.
9. The method of claim 8,
A polyamide-based optical laminated film, wherein the value of the radius of curvature of the curl of the film after standing for 30 minutes in an environment of 25° C. and 60% relative humidity is greater than 30 mm.

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