KR102286935B1 - Films, manufacturing methods of the films, cover films and multi-layered electronic devices - Google Patents

Abstract

Provided are a film, a manufacturing method thereof, a cover film, a multi-layer electronic equipment, etc. The film includes an elastic layer having a storage modulus index K_SM of 20 to 350 Mpa and a haze of 3% or less, represented by equation 1 below, and has a substantially low storage modulus change in a wide temperature range, excellent mechanical properties such as excellent elastic recovery force, and excellent optical properties such as low haze. In the equation 1, SM_n is a storage modulus (Mpa) measured at a temperature of n ℃.

Description

Film, film manufacturing method, cover film and multi-layer electronic equipment

The embodiment relates to a film having substantially low storage modulus change in a wide temperature range, excellent mechanical properties such as excellent elastic recovery force, and excellent optical properties such as low haze, a method for producing a film, a cover film, a multilayer electronic device, etc. .

The form of display devices is diversified and required functions are changing, and the evolution to a thinner and functionalized form on a wider screen is in progress. The shape of the display is also changing from the conventional flat panel shape to the curved shape, and then to foldable, bendable, flexible, etc. That is, the shape of a recent display is changing to a different shape from the existing one, which has simply evolved in the direction of large-area in that it is possible to change the shape such as folding or bending.

As a display screen protection film, PET film with excellent mechanical properties, chemical resistance, and moisture barrier properties is widely used. Polyester protective film with improved optical properties applicable as a protective film for polarizing plates (Korea Registration No. 10-1730854), and a protective film applicable to touch panels (Korea Registration No. 10-1746170) are examples. However, the PET film has a high modulus and may not satisfy the characteristics required for a curved surface or a bent portion, which may be one of the causes of the film floating in a multi-layered display device.

In addition, compared to the hard glass used to protect the display module of the display device mounted on the portable electronic device, the PET film has weak impact mitigation properties (the function to protect the internal devices such as the display module from external impact), so it is sufficient. There is a limit to carrying out the protective function.

The above-mentioned background art is technical information possessed by the inventor in order to derive the embodiments of the present invention or acquired in the process, and cannot necessarily be said to be a known technology disclosed to the general public prior to the present application.

An object of one embodiment is to provide a film having a substantially low storage modulus change in a wide temperature range, excellent mechanical properties such as excellent elastic recovery force, and excellent optical properties such as low haze, and a method of manufacturing the film.

An object of another embodiment is to have excellent mechanical properties such as a substantially low storage modulus and excellent elastic recovery in a wide temperature range including the film, so that layer separation does not occur substantially, so it is advantageous to apply it as a cover window of a multi-layered electronic device, etc. To provide a cover film.

Another object of the embodiment is to provide the use of the film as a cover window for a foldable display, a bendable display, a flexible display, and the like.

It is an object of another embodiment to provide a multilayer electronic device including the cover film having excellent optical properties, no separation between layers even with repeated bending or rolling, and strong resistance to external impact.

It is an object of another embodiment to provide the use of the above-described film applied in a multi-layer electronic device as a cover film.

The film which is an embodiment for solving the above problems includes an elastic layer.

The elastic layer may have a storage modulus index K _SM of 20 to 350 Mpa expressed by Equation 1 below.

[Equation 1]

In Equation 1, SM _n is the storage modulus (Mpa) measured at a temperature of n °C.

The elastic layer may have a recovery force index Rv of greater than 50 expressed by Equation 2 below.

[Equation 2]

In Equation 2, Xo is the length (mm) of the initial elastic layer, X _2% is the length (mm) after stretching the elastic layer by 2%, and Xf is the length (mm) after stretching the elastic layer by 2% at a rate of 50 mm/min. It is the length (mm) of the elastic layer after 100 cycles, assuming that it is restored to its original length at a rate of 50 mm/min as one cycle.

The elastic layer may have a haze of 3% or less.

The elastic layer may have a storage modulus of 3 GPa or less at room temperature.

The elastic layer may have a storage modulus ratio of 0.08 or more at 80°C based on the storage modulus at 20°C.

The elastic layer may have a difference between a storage modulus at -40°C and a storage modulus at 20°C of -1500 to +1500 MPa.

The elastic layer may have a storage modulus of 20 to 2500 Mpa at 0 °C.

The elastic layer may have a storage modulus of 5 Mpa or more at 80 °C.

The elastic layer may have a thickness of less than 2000 um.

The roughness reference value is the larger of Ra1, which is the surface roughness Ra value of one surface, and Ra2, which is the surface roughness Ra value of the other surface.

The elastic layer may have a roughness reference value of 0.5 μm or less.

The film or the elastic layer may have a value obtained by subtracting the yellowness before exposure from the yellowness after exposure for 72 hours at an output of 3.0 W to ultraviolet rays of a wavelength of 280 to 360 nm may be 2 or less.

The elastic layer may include a polymer including an amide residue as a repeating unit.

The elastic layer may include polyamide, polyether block amide (PEBA), thermoplastic polyurethane (TPU), polyether ester copolymer (copolyetherester, COPE), or a mixture thereof.

The elastic layer may have an impact strength of 2500 kJ/m ^{2 or more.}

The elastic layer may have an absorbed energy of 1.4 J or more.

The elastic layer may be disposed on the heat-resistant layer.

The heat-resistant layer may include a polyimide layer or a glass layer.

The haze of the heat-resistant layer may be 3% or less.

The film may further include an adhesive layer disposed on one or both surfaces of the heat-resistant layer.

In the adhesive layer, a difference between a storage modulus at -40°C and a storage modulus at 80°C may be -100 to +100 kPa.

The film may not be lifted even after performing a dynamic folding test of 200,000 times under the conditions of a radius of curvature of 2 mm and a bending frequency of 2 seconds/time.

The film may have an impact strength of 2500 kJ/m ^{2 or more.}

The film may have an absorption energy of 1.4 J or more.

A method of manufacturing a film according to an embodiment comprises the steps of: forming an elastic sheet from a polymer resin containing amide or a residue thereof as a repeating unit; And passing the first assembly on which the elastic sheet is disposed on the carrier film between rollers to provide a second assembly including an elastic layer positioned on the carrier film; including, to prepare the above-described film.

The carrier film may have a surface roughness of a surface in contact with the elastic sheet of 0.01 um or less.

The cover film according to the embodiment includes the film described above.

A multilayer electronic device according to an embodiment includes the cover film described above.

The multilayer electronic device may include a light emitting functional layer and the cover film.

The light emitting functional layer may have a display area that emits or does not emit light according to an external signal.

The cover film may be disposed on one surface of the light emitting functional layer and cover at least a portion of the display area.

The film of the embodiment, the manufacturing method of the film, etc. provide a film having a substantially low storage modulus change in a wide temperature range, excellent mechanical properties such as excellent elastic recovery force, and excellent optical properties such as low haze, an efficient manufacturing method of the film, etc. can do.

The cover film and multi-layer electronic equipment of the embodiment have excellent bending and rolling properties even in a wide temperature range including the film, have excellent optical properties such as low haze, have excellent elastic recovery, and have an effect of inhibiting damage due to external impact and the like can also provide excellent cover films, multi-layer electronic equipment, and the like.

1 (a), (b), (c) is a conceptual diagram illustrating a cross-section of a film according to an embodiment, respectively.
2 (a), (b), (c) is a conceptual diagram illustrating a cross-section of a film according to an embodiment, respectively.
3 is a conceptual diagram illustrating a method of manufacturing a film.
4 is a conceptual diagram illustrating a cross-section of a configuration of a multi-layer electronic device according to an embodiment.
5 (a), (b), and (c) are conceptual views illustrating a cross-section of a configuration of a multi-layer electronic device according to an embodiment, respectively.
6 is a conceptual diagram illustrating the configuration of a multi-layer electronic device according to an embodiment in cross section.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Throughout the specification, like reference numerals are assigned to similar parts.

In the present specification, when a component "includes" another component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In this specification, when a component is "connected" with another component, it includes not only the case of 'directly connected', but also the case of 'connected with another component in the middle'.

In this specification, the meaning that B is positioned on A means that B is positioned so that it directly abuts on A or that B is positioned on A while other configurations are positioned between them, and B is positioned so that it abuts on the surface of A It is not construed as being limited to

In the present specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It means to include one or more selected from the group consisting of.

In this specification, the description of "A and/or B" means "A, B, or A and B".

In this specification, terms such as "first", "second" or "A" and "B" are used to distinguish the same terms from each other unless otherwise specified.

In the present specification, unless otherwise specified, the expression "a" or "a" is interpreted as meaning including the singular or the plural as interpreted in context.

In the present specification, the storage modulus is described based on the measurement of the storage modulus (Storage Modulus, E') by applying the DMA Q800 model of TA instruments, according to ASTM D4065. The device is described based on the result of measuring the storage modulus (E') in Mpa in the temperature range (-40 to 80 °C) by applying 1Hz, 2 °C/min in DMA (Dynamic Mechanical Analysis) tension mode. .

A letter and/or number in conjunction with the name of a compound in the present specification means an abbreviation for the name of the compound.

In the present specification, the relative sizes, thicknesses, etc. of the components shown in the drawings may be exaggerated for the purpose of easy description.

Hereinafter, the present invention will be described in more detail.

The inventors of the embodiment have experimentally confirmed that even if an elastic layer in the form of a film is manufactured with the same thickness by applying a polymer resin, there may be a large difference in the haze value of the elastic layer, etc. depending on the manufacturing process. In addition, it was experimentally confirmed that, even when the same polymer resin was applied, there was a difference in optical properties such as haze value of the elastic layer depending on the manufacturing process. The inventors have manufactured a film having excellent optical properties, modulus properties, etc. applicable to a display area of a multilayer electronic device such as a cover window of a foldable or rolling display, and the like will be described in detail.

1 (a), (b), (c) is a conceptual diagram illustrating a cross-section of a film according to an embodiment, respectively, and (a), (b), (c) of FIG. 2 are each according to an embodiment It is a conceptual diagram illustrating a film in cross section, and FIG. 3 is a conceptual diagram illustrating a method of manufacturing the film. 1 to 3, the elastic layer included in the film, the film, and a method of manufacturing the film will be described.

In order to achieve the above object, the film 190 according to an embodiment includes an elastic layer 100 .

elastic layer (100)

The elastic layer 100 has excellent optical properties.

The elastic layer 100 may have a haze of 3% or less and 2% or less. The elastic layer 100 may have a haze of 1.5% or less and 1.2% or less. The elastic layer 100 may have a haze of 0.01% or more, or 0.1% or more. When the elastic layer has the haze as described above, it is suitable for application to the display area of the display device.

The elastic layer 100 may have a visible light transmittance of 85% or more, 88% or more, and 90% or more. The elastic layer may have a visible light transmittance of 99.99% or less. The elastic layer 100 having these characteristics or the film 190 including the same is advantageously applied as a protective layer (or cover window) of an electronic device.

The elastic layer 100 may have the above-mentioned optical characteristics and also the storage modulus related characteristics described below.

The elastic layer 100 has a storage modulus index of 20 to 350 MPa expressed by Equation 1 below.

[Equation 1]

In Equation 1, K _SM is the storage modulus index of the elastic layer, SM _n is the storage modulus (Mpa) of the elastic layer measured at a temperature of n ℃.

For example, SM _-40 is the storage modulus (Mpa) of the elastic layer measured at a temperature of -40 ℃, SM ₂₀ is the storage modulus (Mpa) of the elastic layer measured at a temperature of 20 ℃, SM ₈₀ is a temperature of 80 ℃ is the storage modulus (Mpa) of the elastic layer measured in

When the elastic layer has the storage modulus index of the above-mentioned value, it may have a relatively stable degree of storage modulus change in a relatively wide temperature range, and thus may have stable elastic properties in a wide temperature range.

The elastic layer 100 may have a storage modulus of 3 GPa or less at room temperature or room temperature. The elastic layer may have a storage modulus of 2 GPa or less at room temperature or room temperature. In the present specification, room temperature is based on about 20 °C, and room temperature is about 25 °C.

The elastic layer 100 has a relatively low storage modulus value at room temperature or room temperature compared to a PET film and the like. With this feature, the elastic layer or the film including the same may have more stable bending properties, and the degree of transmission of an external shock to the article disposed on the back surface may be more relaxed.

The elastic layer 100 may have a high-temperature storage modulus ratio R _80/20 of 0.08 or more. The high-temperature storage modulus ratio R _80/20 is the ratio of the storage modulus at 80° C. based on the storage modulus at 20° C., and is represented by [Equation 1-a] below.

[Formula 1-a]

In Formula 1-a,

R _80/20 is a high-temperature storage modulus ratio, and SM _n is a storage modulus (Mpa) of the elastic layer measured at a temperature of n°C.

The elastic layer 100 may have an R _80/20 of 0.08 or more, 0.10 or more, or 0.15 or more. In the elastic layer, R _80/20 may be 0.20 or more, or 0.25 or more. In the elastic layer, R _80/20 may be 1 or less and 0.85 or less. The elastic layer may have an R _80/20 of 0.7 or less and 0.55 or less.

_{The elastic layer having an R 80/20} in this range is advantageous for application to a bendable cover window in which repeated bending is performed in a wide temperature range. This feature is more advantageous when the elastic layer is laminated with a layer other than the elastic layer and the elastic layer. Specifically, when the elastic layer having the above characteristics is applied, it is relatively easy to control the deterioration of physical properties caused by the difference in storage modulus according to the temperature between each layer. In addition, the elastic layer has excellent elastic properties within a controllable range not only at room temperature or room temperature but also at a high temperature.

The elastic layer 100 may have an R _80/20 of 0.15 to 0.55. The elastic layer may have an R _80/20 of 0.25 to 0.55. In this case, it is possible to substantially control the occurrence of peeling, lifting, etc. at room temperature as well as at high temperature while having stable properties of the elastic layer even after bonding of the elastic layer and the other configuration by using an adhesive layer or the like.

The elastic layer 100 may have a low-temperature storage modulus ratio R _-40/20 of 1.15 or more. The low-temperature storage modulus ratio R _-40/20 is a ratio of the storage modulus at -40°C based on the storage modulus at 20°C, and is expressed by Equation 1-b below.

[Formula 1-b]

In the above formula 1-b,

R _-40/20 is the low-temperature storage modulus ratio,

SM _n is the storage modulus (Mpa) of the elastic layer measured at a temperature of n °C.

The elastic layer 100 may have an R _-40/20 of 1.20 or more, or 1.33 or more. The elastic layer may have an R _-40/20 of 20 or less, or 10 or less. The elastic layer may have an R _-40/20 of 4.9 or less, and 4.5 or less.

_{The elastic layer having an R -40/20} in this range is advantageous to be applied to a bendable cover window in which repeated bending is performed in a wide temperature range. This feature is more advantageous when the elastic layer is laminated with a layer other than the elastic layer and the elastic layer. Specifically, when the elastic layer having the above characteristics is applied, it is relatively easy to control the deterioration of physical properties caused by the difference in storage modulus according to the temperature between each layer. In addition, the elastic layer has excellent elastic properties within a controllable range not only at room temperature or room temperature but also at a low temperature.

The elastic layer 100 may have an R _-40/20 of 1.22 to 4.50. The elastic layer may have an R _-40/20 of 1.22 to 3.8. The elastic layer may have an R _-40/20 of 1.22 to 3.0. In this case, it is possible to substantially suppress the occurrence of peeling, lifting, etc. at room temperature as well as low temperature while having stable properties of the elastic layer even after bonding of the elastic layer and the other configuration by using an adhesive layer or the like.

The difference in the low-temperature storage modulus is the difference between the storage modulus at -40 °C and the storage modulus at 20 °C, and is expressed by Equation 1-c below.

[Formula 1-c]

In the above formula 1-c,

D _-40-20 is the difference in low-temperature storage modulus,

SM _n is the storage modulus (Mpa) of the elastic layer measured at a temperature of n °C.

The elastic layer 100 may have a D _-40-20 of -1500 MPa to 1500 MPa. The elastic layer may have a D _-40-20 of -1000 MPa to 1000 MPa. _{When D -40-20} of the elastic layer is more than 1500 MPa, the difference in storage modulus at room temperature and at low temperature is relatively large, and the elastic properties may be substantially insufficient at low temperature, cracking and tearing due to deformation such as bending, etc. irreversible deformation of _{Preferably, D -40-20} of the elastic layer may be 1000 MPa or less.

The elastic layer 100 may have a -40 °C storage modulus of 2300 Mpa or less, and may be 2000 Mpa or less. The elastic layer may have a -40 °C storage modulus of 200 Mpa or more, 400 Mpa or more, and 500 Mpa or more.

The elastic layer 100 may have a 0 °C storage modulus of 2500 Mpa or less, and 2000 MPa or less. The elastic layer may have a 0 °C storage modulus of 20 Mpa or more, and 150 MPa or more. The elastic layer may have a storage modulus of 180 to 1200 MPa at 0 °C.

The elastic layer 100 may have a storage modulus of 10 Mpa or more at 40 °C, and may be 90 Mpa or more. The elastic layer may have a storage modulus at 40° C. of 3000 MPa or less and 2000 MPa or less. The elastic layer may have a storage modulus of 100 to 1200 MPa at 40 °C.

The elastic layer 100 may have a storage modulus at 80° C. of 4 Mpa or more, and may be 20 MPa or more. The elastic layer may have a storage modulus at 80° C. of 2000 MPa or less and 1000 MPa or less. The elastic layer may have a storage modulus at 80° C. of 40 to 950 MPa, and may be 60 to 350 MPa.

The elastic layer 100 may have a difference between the storage modulus at 80° C. and the storage modulus at -40° C. of -1000 MPa to 1000 MPa. The difference may be expressed as an absolute value by subtracting a small value from a large value for convenience, and in this case, the difference may be 1000 MPa. The elastic layer having the above characteristics has a relatively small difference in storage modulus in a wide temperature range from high temperature to low temperature, so that it can exhibit stable storage modulus properties in a fairly wide temperature range.

The elastic layer 100 having the storage modulus properties for each temperature described above has an appropriate storage modulus value and/or degree of change in a fairly wide temperature range from a low temperature to a high temperature as well as at room temperature or room temperature.

Even if the elastic layer 100 is applied to an article (multi-layer electronic device, etc.) alone or in combination with other layers and repeatedly undergoes deformation such as bending and rolling, the article has excellent circular recovery properties and is at the same time protected from external impact, etc. can be adequately protected.

The elastic layer 100 may have a recovery force index Rv of more than 50 expressed by Equation 2 below.

[Equation 2]

In Equation 2 above,

Xo is the length of the initial elastic layer (mm),

X _2% is the length (mm) after stretching the elastic layer by 2%,

Xf is the length (mm) of the elastic layer after 100 cycles of 2% stretching at a rate of 50 mm/min and restoration to the original length at a rate of 50 mm/min as one cycle.

To test the recovery force index, a fixing part such as a jig for fixing the elastic layer is applied to both ends of the elastic layer. Since the initial length of the elastic layer and the length of the elastic layer after the cycle actually mean the length of repeated tension, Xo, X _2%, and Xf mentioned above are the lengths of the elastic layer between the fixing parts, respectively.

Rv of the elastic layer 100 may be 55 or more, may be 60 or more, may be 68 or more. Rv of the elastic layer may be less than 100, may be less than 99. Rv of the elastic layer may be 95 or less, and may be 90 or less.

When the Rv of the elastic layer is in the above-mentioned range, the elastic layer may have excellent recovery properties even after repeated tensioning, and in particular, even in repeated tension-restoration with a relatively short length such as bending, the initial elastic layer has It has elastic recovery durability that can maintain properties and length substantially well.

The Rv value of the elastic layer is based on the evaluation result after fixing the elastic layer in the form of a film with a thickness of 100 um to the fixing part (eg: jig) of the evaluation device without applying a separate carrier film or support layer. It is not limited, and a measured value by evaluation recognized as equivalent to this may also be recognized as an Rv value.

The elastic layer 100 may have an impact strength of 2500 kJ/m ² or more, may have an impact strength of 3500 kJ/m ² or more, and may have an impact strength of 4500 kJ/m ² or more. The elastic layer 100 may have an impact strength of 5000 kJ/m ² or more, and may have an impact strength of 10000 kJ/m ² or less. The elastic layer with these characteristics absorbs external shock well, but is not easily broken or damaged, so it is excellent in application as a cover film.

The elastic layer 100 may have an absorbed energy of 1.4 J or more, and may have an absorbed energy of 1.5 J or more. The elastic layer 100 may have an absorption energy of 1.6 J or more, and may have an absorption energy of 2.0 J or less. The elastic layer with these characteristics absorbs external shocks well and protects the film itself without easily damaging it.

The impact strength and the absorbed energy are based on the results of evaluating the tensile-impact strength of the elastic layer according to JIS K 7160, respectively, and the specific measurement conditions are those presented in the following laboratory examples. do.

The elastic layer 100 may be in the form of a film having a constant thickness.

The elastic layer 100 may be in the form of an extruded film having a constant thickness.

The elastic layer 100 may be laminated together with other layers to be described later and included in the laminated film.

By "thickness controlled constant" above means to have a thickness adjusted to have a range of -5% to +5% of a predetermined thickness.

The elastic layer 100 may have a thickness of less than 2000 um. The thickness of the elastic layer may be 1500 um or less, and may be 1000 um or less. The thickness of the elastic layer may be 1 um or more. The thickness of the elastic layer may be 50 um to 300 um.

The elastic layer 100 in the form of a film having the above thickness has the above-described storage modulus properties and at the same time excellent optical properties, so that it is suitable for application as a cover film of a display device.

The surface of the elastic layer 100 has a low surface roughness below a predetermined level.

The surface roughness of the elastic layer may have a technical meaning by itself, but may affect the physical properties of the elastic layer in relation to other properties such as optical properties. The inventors have confirmed that the surface roughness of the elastic layer can affect the optical properties of the film, particularly the haze properties, to be maintained below a certain level.

The roughness reference value is the larger of Ra1 which is the surface roughness Ra value of one surface and Ra2 which is the surface roughness Ra value of the other surface.

The roughness reference value of the elastic layer 100 may be 0.5 μm or less.

The roughness reference value of the elastic layer 100 may be less than 0.5 um, may be less than 0.2 um, and may be less than 0.1 um. The roughness reference value of the elastic layer may be greater than 0 um, may be greater than 0.0001 um, and may be greater than or equal to 0.001 um.

When the roughness reference value of the elastic layer is controlled to be less than or equal to a certain level, optical properties, particularly, haze properties, of the elastic layer may be further improved.

The roughness reference value of the elastic layer 100 may be 0.001 to 0.1 um. The roughness reference value of the elastic layer may be 0.0015 to 0.05 um. The elastic layer having such a roughness reference value has better optical properties such as haze, and has excellent utility as an optical film.

Illustratively, one surface of the elastic layer is a surface in contact with the carrier film 92 to be described later, and the other surface of the elastic layer is in contact with a separate sheet protective film 94 or a roll-type device (eg squeezing roll) in the manufacturing process. can be cotton

The Ra1 and Ra2 may be controlled by adjusting the surface roughness of the carrier film and roll-type equipment (or sheet protective film) in contact with one or the other surface of the elastic sheet, respectively, in the manufacturing process of the elastic layer.

Illustratively, when the surface roughness Ra of the carrier film is in the range of 0.8 to 1.2 um, the surface roughness Ra value of one surface of the elastic layer Ra1 may be in the range of 0.8 to 1.2 um.

Illustratively, if the surface roughness Ra of the roll-type equipment is in the range of 0.01 to 0.5 um, Ra2, which is the surface roughness Ra value of the other surface of the elastic layer, may be in the range of 0.01 to 0.5 um.

Illustratively, if the surface roughness Ra of the sheet protective film is in the range of 0.01 to 0.5 um, Ra2, which is the surface roughness Ra value of the other surface of the elastic layer, may be in the range of 0.01 to 0.5 um.

The carrier film 92 may be a polyethylene terephthalate (PET) film, but is not limited thereto.

The sheet protective film 94 may be applied to a polyethylene (PE) film, but is not limited thereto.

The elastic layer 100 may have a Shore D hardness of 20 to 75, specifically 30 to 70. It exhibits adequate strength for application as a cover film, and contributes to imparting excellent impact resistance to the film along with elastic properties.

The elastic layer 100 may have an intrinsic viscosity of 0.8 to 2.5 as measured with meta cresol at 25° C. according to ISO 307:2019.

The elastic layer 100 may have a yellowness (Y.I, Yellow Index) of 1 or less. The yellowness may be a value measured in YI E313 (D65/10) mode by applying a color meter ultra scanpro manufactured by Hunterlab.

The elastic layer 100 may have a value obtained by subtracting the yellowness before exposure from the yellowness after exposure for 72 hours at an output of 3.0 W to ultraviolet rays having a wavelength of 280 to 360 nm may be 2 or less. In the elastic layer, the value obtained by subtracting the yellowness before exposure from the yellowness after exposure for 72 hours at an output of 3.0 W to ultraviolet rays of a wavelength of 280 to 360 nm may be 1 or less. In the elastic layer, the value obtained by subtracting the yellowness before exposure from the yellowness after exposure for 72 hours at an output of 3.0 W to ultraviolet rays of a wavelength of 280 to 360 nm may be 0.1 or more. The elastic layer having these characteristics may have excellent UV durability in which yellowing of the coating layer does not occur even when exposed to UV light.

The elastic layer 100 may be one in which cloudiness is not substantially observed. Substantially, in the elastic layer, the area in which the cloudiness is observed may be less than 1% of the total area. In this case, the total area is based on the total film area applied to the product. The cloudiness can be objectified through haze measurement, and when the haze measurement value is more than 1%, it can be treated as a feeling of cloudiness. The degree of cloudiness may be adjusted by controlling the degree of gelation, molecular weight distribution, and the like of the resin applied to the production of the elastic layer.

The elastic layer 100 may have excellent durability as a result of dynamic bending evaluation.

The dynamic bending evaluation is carried out according to the IEC 62715-6-1 standard, and the elastic layer is subjected to a dynamic bending test of 200,000 times with a radius of curvature of 2 mm and a bending degree of 2 seconds/time at -40°C to determine whether cracks occur in the elastic layer. Check it.

The elastic layer 100 may have excellent durability in which cracks do not substantially occur after a dynamic bending test of 200,000 times with a radius of curvature of 2 mm and a bending degree of 2 seconds/time at -40°C according to the IEC 62715-6-1 standard. .

This means that, considering the characteristic that the elasticity at low temperature is relatively lower than that at room temperature or high temperature, the elastic layer has excellent elasticity even in repeated bending test results in a wide temperature range.

The elastic layer 100 may include a polymer including an amide residue as a repeating unit.

The elastic layer 100 may be a plastic film including a polymer having an amide residue as a repeating unit.

The elastic layer 100 may be an elastomer film including a polymer having an amide residue as a repeating unit.

The amide residue may be 50 wt% or more, or 60 wt% or more, based on the entire polymer included in the elastic layer. The amide residue may be 80 wt% or less, or 70 wt% or less, based on the entire polymer included in the elastic layer. When a polymer having these characteristics is applied to the elastic layer, an elastic layer having better mechanical properties can be provided.

The amide residue may be 92 to 97 mol% based on the entire polymer included in the elastic layer. When such a polymer is applied to the elastic layer, it is possible to provide an elastic layer excellent in both strength properties and elastic properties in a substantially wide range.

The elastic layer 100 may include a polymer, and the polymer may include a rigid region and a soft region in a chain.

The rigid region may be expressed as a rigid segment or a semi-crystalline region. The soft region may be expressed as a soft segment or an amorphous region.

The polymer may include a rigid region and a ductile region at the same time, such that the elastic layer has relatively strong mechanical strength and at the same time flexible and/or elastomeric properties.

The elastic layer may have a polymer chain region (cognate region) including monomers that are substantially classified into the same type. By controlling the degree of partial bonding or alignment of the chains of the polymer chain region (the homologous region), the elastic layer can have both the intended strength and elastic properties. In the elastic layer, monomers that are substantially classified into different types may be further bound to the polymer chain region (cognate region). The elastic layer may have both a partially rigid region having high strength and a partially soft region capable of imparting flexible characteristics to the polymer by having a soft characteristic.

The elastic layer may include elastic polyamide (long chain polyamide).

The elastic polyamide may include an amorphous region that is a soft region and a crystalline region that is a rigid region, and the amorphous region is a matrix, and the crystalline region is distributed in the matrix. .

The rigid region may include more hydrogen-bonded C=O molecules compared to the soft region. The flexible region may include more free C=O bonds that are not hydrogen bonded compared to the rigid region. The content of hydrogen-bonded C=O molecules included in the rigid region and the flexible region may be confirmed by measuring FT-IR spectra.

The elastic polyamide may include semicrystalline polyamide. The elastic polyamide may include an amorphous polyamide. The elastic polyamide may include a mixture of semi-crystalline polyamide and amorphous polyamide. The elastic polyamide preferably comprises more than 50% by weight of semi-crystalline polyamide, based on the total elastic polyamide.

The elastic polyamide may be a homo polyamide, a polyamide copolymer, or a mixture thereof. The elastic polyamide may be prepared as a homo polyamide by polymerizing one kind of monomer selected from amino acids, lactams, or mixtures of diacids and diamines. The elastic polyamide may be prepared as a polyamide copolymer by polymerizing two or more monomers selected from amino acids, lactams, or mixtures of diacids and diamines.

The elastic polyamide can be prepared by combining a molecule having an amide group at one end and another molecule having a carboxyl group at one end.

Examples of the monomers applied to prepare the elastic polyamide are as follows, but are not limited thereto.

The aliphatic diacid may be, for example, adipic acid (6), azelaic acid (9), sebacic acid (10), dodecanedioic acid (12), etc., but is not limited thereto. does not

The aromatic diacid may be, for example, terephthalic acid (T), isophthalic acid (I), or the like, but is not limited thereto.

Aliphatic diamines include, for example, butylenediamine (4), hexamethylene-diamine (6 or HMDA), isomers of trimethylhexamethylenediamine (TMHMDA), octamethylenediamine (8) , decamethylenediamine (decamethylenediamine, 10), dodecamethylenediamine (dodecamethylenediamine, 12), etc. may be present, but is not limited thereto.

The aromatic diamine may be, for example, meta-xylenediamine (MXD), but is not limited thereto.

Cycloaliphatic diamines are, for example, bis(3,5-dialkyl-4-aminocyclohexyl)methane, bis(3,5-dialkyl-4-amino) Cyclohexyl) ethane (bis (3,5-dialkyl-4-aminocyclohexyl) ethane), bis (3,5-dialkyl-4-aminocyclohexyl) propane (bis (3,5-dialkyl-4-aminocyclohexyl) propane ), bis (3,5-dialkyl-4-aminocyclohexyl) butane (bis (3,5-dialkyl-4-aminocyclohexyl) butane), bis (3-methyl-4-aminocyclohexyl) methane (bis ( 3-methyl-4-aminocyclohexyl)methane, BMACM, MACM or B), bis(p-aminocyclohexyl)methane (PACM), isopropylidenedi(cyclohexylamine), PACP), isophorone It may be diamine (isophoronediamine, IPD), 2,6-bis(aminomethyl) norbornane (2,6-bis(aminomethyl)norbornane, BAMN), piperazine, or a mixture thereof, but is not limited thereto.

The other diamine may be, for example, isophoronediamine (IPDA), 2,6-bis-(aminomethyl)norbornane (BAMN), and the like, but is not limited thereto.

The lactam may be, for example, caprolactam (caprolactam, L6), lauryllactam (L12), and the like, but is not limited thereto.

The amino acid may be, for example, 11-aminoundecanoic acid (11), 11-(N-heptyl-amino)undecanoic acid (11-(N-heptyl-amino)undecanoic acid, NHAU), etc., but is limited thereto doesn't happen

The elastic polyamide may include an aliphatic polyamide. The elastic polyamide may be made of an aliphatic polyamide.

The elastic polyamide may include a semiaromatic polyamide. The elastic polyamide may be made of semi-aromatic polyamide.

Aliphatic polyamides are, for example, polycaprolactam (PA 6), polyundecanamide (PA 11), poly-lauryllactam (PA 12), polybutylene adipamide (polybutylene adipamide, PA 46), polyhexamethylene adipamide (PA 66), polyhexamethylene azelamide (PA 69), polyhexamethylene sebacamide (PA 610), polyhexamethylene dodecanedi Amide (polyhexamethylene dodecanediamide, PA 612), polydecamethylene dodecanediamide (PA 1012), polydecamethylene sebacamide (PA 1010), polydodecamethylene dodecanediamide (PA 1212 dodecanediamide) ), polyamide copolymers PA 11/NHUA, PA BACM6, PA BACM10, PA BACM12, PA 6/66, PA 6/12, or a mixture thereof, but is not limited thereto. According to an embodiment, the polyamide copolymer may be PA 6/66, PA 6/610, PA6/12, or a mixture thereof.

The semiaromatic polyamide can be, for example, PA 6/6T, PA 66/6T, PA 6T/6I, PA 66/6T/6I, PA 11/6T, PA 12/6T, PA MXD6, PA MXD10 or mixtures thereof. However, the present invention is not limited thereto.

Amorphous polyamides include, for example, polyamides, polyhexamethylene isophthalamide (PA 6I), polytrimethylhexamethylene terephthalamide (PA TMHMDAT), PA BACM12; As amide copolymers: PA 6/BMACPI, PA 6/BAMNT, PA 11/BMACMI, PA 11/BMACMT/BMACMI, PA 11/BACM.I/IPDA.I, PA 12/BMACM.I, PA 12/BACMT/BACMI , PA 12/BMACMT/BACMI, PA 12/BACMI/IPDAI, PA 6T/6I/BACMI, PA 6T/6I/BACMT/BACMI; or a mixture thereof, but is not limited thereto.

Preferably, the polyamide is a semi-crystalline polyamide. As used herein, semi-crystalline polyamide may mean a substantially linear aliphatic polyamide. Preferably, the semi-crystalline polyamide may be any one selected from PA 6, PA 11, PA 12, PA 10.10, PA 10.12, PA 6.10, PA 6.12, and combinations thereof.

The elastic polyamide may be, for example, Rilsan®, Rilsamid®, etc. manufactured by Arkema, but is not limited thereto.

The elastic layer 100 may include polyether block amide (PEBA). The polyether block amide includes two phases: a polyamide region that is a rigid region and a polyether region that is a soft region. The polyamide region may constitute a hard region in a substantially crystalline phase with a melting point of about 80 ° C. or higher, specifically about 130 to 180 ° C., and the polyether region has a glass transition temperature of about -40 ° C. or less, specifically As a result, it exists in a low temperature region of -80 to -40 °C to constitute a substantially amorphous soft region.

The polyether block amide may be a combination of a polyamide having two or more carboxyl groups in a molecule and an ether having two or more hydroxyl groups in a molecule.

The elastic layer 100 may include a polyether block amide, and the polyether block amide may include at least one copolymer including a polyether block and a polyamide block. A polyether block amide comprises at least one polyether block and at least one polyamide block.

The copolymer (polyether block amide) including a polyether block and a polyamide block may be a polyether block including a reactive end and a polyamide block including a reactive end by condensation polymerization.

The polyether block amide may be a condensation polymer comprising a polyamide block comprising a diamine end and a polyoxyalkylene block comprising a dicarboxyl end.

The polyether block amide may be a condensation polymer comprising a polyamide block comprising a dicarboxyl terminus and a polyoxyalkylene block comprising a diamine terminus. The polyoxyalkylene block may be obtained by subjecting an aliphatic α,ω-dihydroxylated polyoxyalkylene block known as polyetherdiol to a cyanoethylation reaction and hydrogenation reaction.

The polyether block amide may be a condensation polymer including a polyamide block including a dicarboxyl terminus and a polyetherdiol block. In this case, the polyether block amide is a polyetheresteramide.

Illustratively, the polyamide block comprising dicarboxyl chain ends may comprise a condensation polymer of a polyamide precursor in the presence of a chain limiting dicarboxylic acid. Illustratively, the polyamide block comprising diamine chain ends may comprise a condensation polymer of a polyamide precursor in the presence of a chain limiting diamine.

Illustratively, the polyamide block comprising dicarboxyl chain ends may comprise a condensation polymer of an α,ω-aminocarboxylic acid, a lactam or a dicarboxylic acid and a diamine in the presence of a chain limiting dicarboxylic acid. The polyamide block is preferably polyamide 12 or polyamide 6.

Polyether Block The polyamide may include blocks having a randomly distributed unit structure.

Advantageously, the following three types of polyamide blocks can be applied.

In a first type, the polyamide block may comprise a condensation polymer of a carboxylic acid and an aliphatic or aryl aliphatic diamine. The carboxylic acid may have 4 to 20 carbon atoms, preferably 6 to 18 carbon atoms. The aliphatic or aryl aliphatic diamine may have from 2 to 20 carbon atoms, preferably from 6 to 14 carbon atoms.

The dicarboxylic acid is, for example, 1,4-cyclohexanedicarboxylic acid (1,4-cyclohexanedicarboxylic acid), 1,2-cyclohexyldicarboxylic acid (1,2-cyclohexyldicarboxylic acid), 1,4-butane 1,4-butanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, 1,12-dodecanedicarboxylic acid (1,12-dodecanedicarboxylic acid), 1,14-tetradecanedicarboxylic acid (1,14-tetradecanedicarboxylic acid), 1,18-octadecanedicarboxylic acid (1,18-octadecanedicarboxylic acid), terephthalic acid acid), isophthalic acid, haphthalenedicarboxylic acid, dimerized fatty acid, and the like.

The diamine is, for example, 1,5-tetramethylenediamine (1,5-tetramethylenediamine), 1,6-hexamethylenediamine (1,6-hexamethylenediamine), 1,10-decamethylenediamine (1,10-decamethylenediamine), 1,12-dodecamethylenediamine (1,12-dodecamethylenediamine), trimethyl-1,6-hexamethylenediamine (trimethyl-1,6-hexamethylenediamine), 2-methyl-1,5-pentamethylenediamine (2-methyl -1,5-pentamethylenediamine), the isomers of bis(3-methyl-4-aminocyclohexyl)methan, BMACM), 2,2-bis(3- methyl-4-aminocyclohexyl)propane (2,2-bis(3-methyl-4-aminocyclohexyl)propane, BMACP), bis(para-aminocyclohexyl)methane (bis(para-aminocyclohexyl)methane, PACM), isophoronediamine (IPD), 2,6-bis(aminomethyl) norbornane (2,6-bis(aminomethyl)norbornane, BAMN), piperazine (Pip), meta-xylylenediamine (meta- xylylenediamine, MXD) and para-xylylenediamine (PXD).

Advantageously, the first type of polyamide block is PA 412, PA 414, PA 418, PA 610, PA 612, PA 614, PA 618, PA 912, PA 1010, PA 1012, PA 1014, PA 1018, MXD6, PXD6, MXD10 or PXD10.

A second type of polyamide block is at least one α,w-aminocarboxylic acid and/or at least one having 6 to 12 carbon atoms in the presence of a dicarboxylic acid or diamine having 4 to 12 carbon atoms. Condensation polymers of lactams may be included.

Examples of the lactam include caprolactam, onantholactam, lauryllactam, and the like.

Examples of the α, ω-aminocarboxylic acid include aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-amino and 12-aminododecanoic acids.

Advantageously, the second type of polyamide block may comprise polyamide 11, polyamide 12 or polyamide 6.

A third type of polyamide block may comprise a condensation polymer of at least one α,ω-aminocarboxylic acid (or at least one lactam), at least one diamine and at least one dicarboxylic acid.

In this case, the polyamide (PA) block may be prepared by condensation polymerization of the following diamines, diacids, and comonomers (or comonomers).

As the diamine, for example, a linear aliphatic diamine, an aromatic diamine, a diamine having X carbon atoms, and the like can be applied. As the diacid, for example, dicarboxylic acids, acids having Y carbon atoms, and the like can be applied. A comonomer or comonomers {Z} is a lactam having Z carbon atoms, an α,ω-aminocarboxylic acid, and at least one diamine having X 1 carbon atoms and at least one diamine having Y 1 carbon atoms. The dicarboxylic acid may be selected from a mixture containing substantially the same mole. However, (X1, Y1) is different from (X, Y).

The comonomer or comonomers {Z} may be included in an amount of 50 wt% or less, preferably 20 wt% or less, advantageously 10 wt% or less, based on the total weight of the bound polyamide precursor monomer.

The condensation reaction according to the third type may be carried out in the presence of a chain limiting agent selected from dicarboxylic acids.

Advantageously, dicarboxylic acids having Y carbon atoms can be used as chain limiting agent, said dicarboxylic acids being introduced in a stoichiometric excess relative to said at least one diamine.

As an alternative form of the third type, the polyamide block optionally in the presence of a chain limiting agent is at least two α, ω-aminocarboxylic acids having 6 to 12 carbon atoms, or at least two lactams, or carbon Condensation polymers of lactams and aminocarboxylic acids having different numbers of atoms may be included.

The aliphatic α,ω-aminocarboxylic acid is, for example, aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid. (12-aminododecanoic acid) and the like.

The lactam may be, for example, caprolactam, onantholactam, lauryllactam, and the like.

The aliphatic diamine may be, for example, hexamethylenediamine, dodecamethylene-diamine, or trimethylhexamethylenediamine.

The alicyclic diacid may be, for example, 1,4-cyclohexanedicarboxylic acid.

The aliphatic diacid is, for example, butanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, dimer fatty acid (preferably a dimer ratio of 98% or more; preferably hydrotreated) ; those sold under the trade name Pripol by Uniqema or Empol by Henkel), polyoxyalkylene-α,ω-diacid, and the like.

The aromatic diacid may be, for example, terephthalic acid (T), isophthalic acid (I), or the like.

The cycloaliphatic diamine is, for example, isomers of bis(3-methyl-4-aminocyclohexyl)methane (BMACM) and 2,2-bis(3-methyl-4-aminocyclohexyl)propane (BMACP), bis( para-aminocyclohexyl)methane (PACM) and the like.

Other diamines may be, for example, isophoronediamine (IPD), 2,6-bis(aminomethyl)novonane (BAMN), piperazine, and the like.

Examples of aryl aliphatic diamines include, but are not limited to, meta-xylylenediamine (MXD) and para-xylylenediamine (PXD).

Examples of third types of polyamide blocks are PA 66/6, PA 66/610/11/12 and the like.

In PA 66/6, 66 represents a hexamethylenediamine unit condensed with adipic acid, and 6 represents a unit introduced by condensation of caprolactam.

In PA 66/610/11/12, wherein 66 represents a hexamethylenediamine unit condensed with adipic acid, 610 represents a hexamethylenediamine unit condensed with sebacic acid, and 11 is a condensation of aminoundecanoic acid represents the introduced unit, and 12 above represents the unit introduced by the condensation of lauryl lactam.

The number average molar mass (Mn) of the polyamide block may be 400 to 20000 g/mol, preferably 500 to 10000 g/mol.

As the polyether (PE) block, for example, one or more polyalkylene ether polyols, especially polyalkylene etherdiol, polyethylene glycol (PEG), polypropylene glycol (PPG) ), polytrimethylene glycol (PO3G), polytetramethylene glycol (PTMG), and mixtures or copolymers thereof are preferred. The polyether block may _{comprise a polyoxyalkylene arrangement comprising NH 2} chain ends, wherein the arrangement is introduced by cyanoacetylation of an aliphatic α,ω-dihydroxy polyoxyalkylene arrangement known as polyetherdiol. can be Specifically, Jeffamine (eg, Jeffamine® D400, D2000, ED2003 or XTJ542 from Huntsman) may be used.

Said at least one polyether block is preferably a polyalkyleneether polyol such as for example PEG, PPG, PO3G, PTMG, a polyether _{comprising NH 2} at the chain terminus and comprising a polyoxyalkylene arrangement, they are in a random arrangement and/or or one or more polyethers selected from block-arranged copolymers (ether copolymers), and mixtures thereof.

The polyether block may be included in an amount of 10 to 80% by weight, preferably 20 to 60% by weight, preferably 20 to 40% by weight, based on the total weight of the copolymer.

The number average molecular weight of the polyether block may be 200 to 1000 g/mol (excluding the critical point), preferably 400 to 800 g/mol (including the critical point), preferably 500 to 700 g/mol.

The polyether block may be introduced from polyethylene glycol. The polyether block may be introduced from polypropylene glycol. Polyether blocks can be produced from polytetramethylene glycol. The polyether block may be copolymerized with a polyamide block comprising a carboxyl terminus to form a polyether block amide. After the polyether block is amination to be converted to polyetherdiamine, it can be condensed with a polyamide block containing carboxyl termini to form a polyether block amide. The polyether block may be mixed with a polyamide precursor and a chain limiting agent to form a polyether block amide comprising statistically dispersed units.

Examples of the polyether include polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene glycol (PTMG). Polytetramethylene glycol is also known as polytetrahydrofuran (PTHF). Polyether blocks can be introduced into the chains of polyether block amides from the diol or diamine form, which polyether blocks are referred to as PEG blocks, PPG blocks or PTMG blocks, respectively.

The polyether block is derived from ethylene glycol (-OC ₂ H ₄ -), propylene glycol (-O-CH ₂ -CH(CH ₃ )-), or tetramethylene glycol (-O-(CH ₂ ) ₄ -) Even including units other than units, the polyether block is included in the scope of the embodiment.

The number average molar mass of the polyamide blocks may advantageously be between 300 and 15,000, preferably between 600 and 5000. The number average molar mass of the polyether block may be 100 to 6000, preferably 200 to 3000.

Advantageously, the content of polyamide blocks comprised in the polyether block amides may be at least 50% by weight based on the total polyether block amides. This may mean the probability of a statistical distribution within the polymer chain. The content of the polyamide is preferably 50 to 80% by weight. The content of the polyether contained in the polyether block amide is preferably 20 to 50% by weight based on the total polyether block amide.

Preferably, the number average molar mass ratio of the polyamide block and the polyether block of the copolymer may be 1:0.25 to 1, and the number average molar mass of the polyamide block and the polyether block of the copolymer is 1000/1000, respectively. , 1300/650, 2000/1000, 2600/650 or 4000/1000.

Polyether block amide is prepared by a manufacturing method comprising a first step of preparing a polyamide block and a polyether block, and a second step of preparing an elastic polyether block amide by condensation polymerization of the prepared polyamide block and polyether block can be Polyether block amides can be prepared by condensation polymerization of monomers in a single step.

The polyether block amides may exemplaryly exhibit a Shore D hardness of from 20 to 75, advantageously from 30 to 70. The polyether block amide may have an intrinsic viscosity of 0.8 to 2.5 as measured with meta cresol at 25°C. Intrinsic viscosity is measured according to ISO 307:2019. Specifically, the intrinsic viscosity measurement in the solution is measured in a metacresol solution of 0.5% by weight relative to the total solution at 25°C using an Ubbelohde viscometer.

Examples of the polyether block amide include, but are not limited to, Pebax® of ARKEMA, Pebax® Rnew®, and VESTAMID® E of Evonik Corporation (EVONIK).

The elastic layer 100 may include a copolymer of thermoplastic polyurethane (TPU), that is, a polyurethane block (PU), also called polyether urethane, and a polyether block (PE).

TPU is a polyether diol or polyester diol (e.g., poly (butyladipate), polycarpolactonediol), which is a soft PE block, and a hard PU block. can The PU block and the PE block may be connected by a bond generated by the reaction of an isocyanate group of a polyether with a hydroxyl group of a polyetherdiol.

As used herein, the polyurethane comprises one or more diisocyanates selected from aromatic diisocyanates (eg MDI, TDI) and/or aliphatic diisocyanates (eg HDI or hexamethylenediisocyanate) and one It refers to a product produced by reaction with a diol (eg, butanediol, ethylene glycol) having a shorter chain length than above.

The elastic layer may include a polyetherester copolymer (COPE).

COPE may comprise a thermoplastic elastomer comprising at least one polyether block (PE) and at least one polyester block (homopolymer or ester copolymer).

The COPE may comprise a flexible PE block derived from a polyetherdiol, a rigid polyester block resulting from the reaction of at least one dicarboxylic acid and at least one short chain extender diol unit. The PES block and the PE block may be connected by an ester bond introduced by reaction of an acid group of dicarboxylic acid with a hydroxyl group of polyetherdiol. The short chain extender diol may be selected from the group consisting of neopentylglycol and an aliphatic glycol of the _{formula HO(CH 2} ) _{n OH, wherein n is an integer from 2 to 10.}

Polyether and diacid chains form flexible blocks, while diacid chains and glycol or butanediol chains form rigid polyetherester copolymer hard blocks. Advantageously, the diacid may be an aromatic dicarboxylic acid having 8 to 14 carbon atoms. The aromatic dicarboxylic acid is replaced with at least one other aromatic dicarboxylic acid having 8 to 14 carbon atoms within 50 mole % of the total aromatic dicarboxylic acid and/or 2 within 20 mole % of the total aromatic dicarboxylic acid aliphatic dicarboxylic acids having from to 14 carbon atoms.

Aromatic dicarboxylic acid is, for example, terephthalic acid, isophthalic acid, bibenzoic acid, naphthalene dicarboxylic acid, 4,4-diphenylenedicarboxylic acid (4,4'-diphenylenedicarboxylic acid) , bis (p-carboxyphenyl) methane acid (bis (p-carboxyphenyl) methane acid), ethylene bis p-benzoic acid (ethylene bis p-benzoic acid), 1,4-tetramethylene bis (p- oxybenzoic acid) (1 -4 tetramethylene bis (p-oxybenzoic acid)), ethylene bis (p-oxybenzoic acid), 1,3-trimethylene bis (p-oxybenzoic acid) (1,3-trimethylene bis (p-oxybenzoic) acid) and the like.

Examples of the glycol include ethylene glycol, 1,3-trimethylene glycol, 1,4-tetramethylene glycol, 1,6-hexamethylene glycol, 1,3-propylene glycol, 1,8-octamethylene glycol, 1,10 - Decamethylene glycol, etc.

COPE includes polyether units derived from polyetherdiols, such as polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene glycol (PO3G) or polytetramethylene glycol (PTMG), and dicarboxylic acids (e.g. For example, terephthalic acid) and a glycol (eg, ethanediol, 1,4-butanediol) may include a polyester unit introduced. The polyether ester copolymer is disclosed in European Patents EP402883 and EP405227, the contents of which are incorporated herein by reference.

The elastic layer may include the polyamide, the PEBA, the TPU, the COPE, or a mixture thereof.

A method of manufacturing the elastic layer using the polymer resin will be described later.

Film 190, use of film 190

The film 190 according to another embodiment includes an elastic layer 100 .

For the detailed description of the elastic layer 100, the description above is applied as it is, and detailed description is omitted to avoid duplication of the description.

The film 190 may further include a carrier film 92 positioned on one surface 100a of the elastic layer.

The carrier film 92 may be a film having a thickness of 50 um, and in consideration of various aspects such as chemical resistance and dimensional stability, a PET film may be applied.

The carrier film 92 may be, for example, a PET film of 50 to 250 um.

The carrier film 92 may serve as a release film 150 to be described later.

One surface of the carrier film 92 may be in direct contact with the elastic layer 100 .

In the manufacturing process of the elastic layer 100 , the surface roughness of one surface of the carrier film 92 may be transferred to one surface of the stratified layer in contact therewith.

The surface roughness Ra of one surface of the carrier film 92 may be 0.5 um or less, and may be 0.2 um or less. The surface roughness Ra of one surface of the carrier film 92 may be greater than 0 um, may be greater than 0.0001 um, and may be greater than or equal to 0.001 um.

The surface roughness Ra of one surface of the carrier film 92 may be 0.001 to 0.1 um. The carrier film having such roughness may provide the elastic layer having a lower haze value by controlling the surface roughness of the elastic layer.

The film 190 may include a film laminate (film, 190 ) including the elastic layer 100 and the carrier film 92 . The carrier film may serve as a release film.

The film 190 may further include a sheet protective film 94 positioned on the other surface 100b of the elastic layer.

The sheet protective film 94 may be, for example, a PE film or a PET film. The thickness of the sheet protective film is not particularly limited.

One surface of the sheet protective film may be in direct contact with the other surface 100b of the elastic layer. When a sheet protective film is applied in the manufacturing process of the elastic layer, the surface roughness of one surface of the sheet protective film may control the surface roughness of the other surface of the elastic layer.

The surface roughness Ra of one surface of the sheet protective film 94 may be 0.5 um or less, and may be 0.2 um or less. The surface roughness Ra of one surface of the sheet protective film 94 may be greater than 0 um, may be 0.0001 um or more, and may be 0.001 um or more.

The surface roughness Ra of one surface of the sheet protective film may be 0.001 to 0.1 um. The sheet protective film having such roughness can provide an elastic layer having a lower haze value by controlling the surface roughness of the elastic layer.

The film 190 may include a laminate including an elastic layer 100 and a sheet protective film 94 positioned on the elastic layer.

The film 190 may include a laminate including a carrier film 92 , an elastic layer 100 positioned on the carrier film, and a sheet protective film 94 positioned on the elastic layer.

The film 190 may further include an adhesive layer 130 on one side or the other side of the elastic layer, if necessary.

The adhesive layer 130 may be an optical adhesive layer having excellent light transmittance and/or transparency. For example, a laminate including an optically clear adhesive (OCA), a pressure sensitive adhesive (PSA), or a combination thereof may be applied.

In the adhesive layer 130 , the difference between the storage modulus at 80° C. and the storage modulus at -40° C. may be -100 to 100 kPa, and may be -80 to 80 kPa. The adhesive layer 130 may have a value obtained by subtracting a storage modulus at -40°C from a storage modulus at 80°C of 0.01 to 100 kPa, may be 0.1 to 80 kPa, and may be 1 to 50 kPa. When the adhesive layer 130 having such a storage modulus characteristic is applied to the film 10, the elastic recovery force and elastic durability of the film can be further improved, and particularly when applied as a window cover of a flexible or rollable display. useful.

The elastic layer 100 may be disposed on the release film 150 . An adhesive layer may be disposed between the elastic layer and the release film. In this case, the film 190 may be a laminate in which the release film 150 , the adhesive layer 130 , and the elastic layer 100 are sequentially stacked.

The release film 150 may be, for example, a PET film, but is not limited thereto. In addition, the carrier film 92 or the sheet protective film 94 described above may be applied as the release film 150 .

The elastic layer 100 may be disposed on the heat-resistant layer 120 .

The film 190 may include an elastic layer 100 disposed on the heat-resistant layer 120 .

The film 190 may include an adhesive layer 130 positioned between the heat-resistant layer 120 and the elastic layer 100 . The adhesive layer 130 may be applied with the adhesive layer described above.

The film 190 may not include a separate adhesive layer between the elastic layer 100 and the heat-resistant layer 120 . At this time, the elastic layer 100 may be attached to the heat-resistant layer 120 in a melt-adhesive manner.

The heat-resistant layer 120 may be a polyimide film, a glass layer, or a laminate thereof.

A glass layer having heat resistance and insulating properties while having a small radius of curvature may be applied. Exemplarily, the radius of curvature of the glass layer may be 2 mm or less.

The polyimide film may be a layer made from a polyamide-imide polymer. Since the prepared layer includes an imide repeating unit, it may correspond to a polyimide film in a broad sense.

The polyamide-imide polymer includes a polymer formed by polymerizing an aromatic diamine compound, an aromatic dianhydride compound, and a dicarbonyl compound. Specifically, the polyamide-imide polymer may be obtained by polymerizing an aromatic diamine compound, an aromatic dianhydride compound, and a dicarbonyl compound in an organic solvent.

The aromatic diamine compound is 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoro Ropropane (HFBAPP), 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether (BTFDPE), 2,2-bis(4-(4-amino-2-(tri fluoromethyl)phenoxy)phenyl)hexafluoropropane (HFFAPP), or 3,5-diaminobenzotrifluoride (DATF).

Specifically, the aromatic diamine compound may be a compound represented by Formula 1-1 below.

[Formula 1-1]

The aromatic dianhydride compound is 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6-FDA), 4,4'-oxydiphthalic anhydride (ODPA), or 2,3,3′,4′-biphenyltetracarboxylic acid dianhydride (BPDA).

Specifically, the aromatic dianhydride compound may be a compound represented by Formula 2-1 below.

[Formula 2-1]

The aromatic diamine compound and the aromatic dianhydride compound may be reacted in a molar ratio of 1:0.95 to 1.05 to form a polymer.

The dicarbonyl compound may be a compound represented by Formula 3-1 or Formula 3-2 below.

[Formula 3-1]

[Formula 3-2]

The aromatic diamine compound and the dicarbonyl compound may be reacted in a molar ratio of 1:0.95 to 1.05 to form a polymer.

The polyimide film may include at least one of repeating units represented by Formulas 4-1 to 4-3 below.

[Formula 4-1]

In Formula 4-1, n is an integer of 1 to 400.

[Formula 4-2]

In Formula 4-2, x is an integer of 1 to 400.

[Formula 4-3]

In Formula 4-3, y is an integer of 1 to 400.

The polyimide film may include the imide repeating unit and the amide repeating unit in a molar ratio of 1:1 to 4.

The polyimide film may have excellent transparency along with excellent mechanical properties, chemical resistance, heat resistance, and the like.

The polyimide film may have a modulus of 5.0 GPa or more based on a thickness of 50 μm.

The polyimide film may have a surface hardness of HB or higher.

The polyimide film may have a yellowness of 5 or less based on a thickness of 50 μm.

The polyimide film may have a haze of 2% or less based on a thickness of 50 μm.

The polyimide film may be a transparent polyimide film.

The polyimide film may have a light transmittance of 85% or more measured at 550 nm based on a thickness of 50 μm.

The polyimide film may have a tensile strength of 15 kgf/mm ^{2 or} more based on a thickness of 50 μm.

The polyimide film may have an elongation of 15% or more based on a thickness of 50 μm.

The film 190 may further include an adhesive layer 130 ′ disposed to face the elastic layer 100 with the heat-resistant layer 120 interposed therebetween. Since the description of the adhesive layer 130 ′ overlaps with the description of the adhesive layer 130 above, a detailed description thereof will be omitted.

The film 190 may further include a release film 150 disposed to face the heat-resistant layer 120 with the adhesive layer 130 ′ interposed therebetween. When the film further includes a release film, the adhesion process with other layers can be facilitated. Since the description of the release film overlaps with that described above, the description thereof will be omitted.

The film 190 may further include a hard coating layer 140 disposed on the elastic layer.

The hard coating layer 140 may be applied as a hard coating layer applied to a display, and may be applied without limitation as long as lifting does not occur in a bending test to be described later.

The film 190 may further include a polarization layer 360 .

The polarization layer 360 may be disposed under one surface 100a of the elastic layer. In this case, the film 190 may include a laminate in which the polarizing layer 360 and the elastic layer 100 are laminated. In addition, the film 190 may include a laminate in which a polarizing layer 360 , a heat-resistant layer 120 , and an elastic layer 100 are sequentially stacked. In this case, the adhesive layers 130 and 130 ′ may be disposed between the polarizing layer and the elastic layer, between the polarizing layer and the heat-resistant layer, and/or between the heat-resistant layer and the elastic layer. In addition, when the adhesive layer is not disposed, adjacent layers may be adhered to each other in a hot-melt manner.

The film 190 may further include a sensor layer 340 . In this case, the film 190 may include a laminate in which the sensor layer 340 and the elastic layer 100 are stacked. In addition, the film 190 may include a laminate in which the sensor layer 340 , the polarization layer 360 , and the elastic layer 100 are sequentially stacked. The film 190 may include a laminate in which the sensor layer 340 , the heat resistance layer 120 , and the elastic layer 100 are sequentially stacked. The film 190 may include a laminate in which the sensor layer 340 , the polarization layer 360 , the heat resistance layer 120 , and the elastic layer 100 are sequentially stacked. At this time, between the sensor layer and the elastic layer, between the sensor layer and the polarizing layer, between the sensor layer and the heat-resistant layer, between the polarizing layer and the heat-resistant layer, and/or between the heat-resistant layer and the elastic layer, respectively, the adhesive layer 130 , 130') may be disposed. In addition, when the adhesive layer is not disposed, adjacent layers may be adhered to each other in a melt-adhesive manner.

The film 190 is implemented according to the IEC 62715-6-1 standard, and the elastic layer is subjected to a dynamic bending test of 200,000 times at -40°C with a radius of curvature of 2 mm and a bending degree of 2 seconds/time, after which the elastic layer 100 and another layer A lifting phenomenon may not occur at this adhered interface. This means that, in consideration of the characteristic that the elasticity at low temperature is relatively lower than that at room temperature or high temperature, the elastic layer has excellent recovery power even in repeated bending test results in a wide temperature range.

The film 190 may have an impact strength of 2500 kJ/m ^{2 or more.} The film 190 may have an impact strength of 3500 kJ/m ² or more, and may have an impact strength of 4500 kJ/m ² or more. The film 190 may have an impact strength of 5000 kJ/m ² or more, and may have an impact strength of 10000 kJ/m ² or less. A film having these characteristics absorbs external shocks well, but is not easily broken or damaged, so it has excellent usability as a cover film.

The film 190 may have an absorption energy of 1.4 J or more. The film 190 may have an absorption energy of 1.5 J or more. The film 190 may have an absorption energy of 1.6 J or more, and an absorption energy of 2.0 J or less. A film with these characteristics absorbs external shocks well, so the film itself is not easily damaged, and the degree of shock transmission inside the film is alleviated, so it is excellent in application as a cover film.

The film 190 may have a difference in yellowness of 2 or less before and after irradiating UVB with 3.0 W at 280 to 360 nm for 72 hours, and may be less than 1. In addition, the difference in the yellowness of the film may be 0.8 or less, and may be 0.6 or less. The yellowness difference of the film may be 0.01 to 0.6, and may be 0.01 to 0.45. The film 190 having these characteristics does not yellow even when exposed to strong ultraviolet rays for a long time and can maintain excellent optical properties.

The film 190 may have a haze of 2% or less and 1% or less. The film may have a haze of 0.8 or less, or 0.7 or less. The film may have a haze of 0.01 or more. When the film 190 has such haze characteristics, it may have excellent optical characteristics and transparency.

The use of the film 190 may be a cover window of a multi-layer electronic device.

The use of the film 190 may be applied as a cover layer of a display device.

The cover layer refers to a layer that forms an outer shape of at least a part of the device and serves to protect the equipment inside, and is not necessarily limited to being disposed at the outermost portion of the equipment. In particular, when the cover layer is disposed on the display area of the display, it is referred to as a cover window.

The use of the film 190 may be a cover layer of a bendable or foldable multilayer electronic device in which a portion of the device is folded.

The use of the film 190 may be as a cover layer for a rollable device in which some or all of the device can be reversibly rolled or unwound.

The film 190 may be included in the protective film of the display.

When the film 190 is applied as a protective film of the display, it has a storage modulus value of an appropriate level in a wide temperature range and has stable bending or flexible properties in a wide temperature range. Impact transmitted to the article protected by the elastic layer can be further mitigated.

The film 190 may have excellent durability and recovery power even in a repeated bending or flexible environment.

The film 190 may suppress the occurrence of a lifting phenomenon between the elastic layer and the layer in direct contact with the elastic layer 100 by applying the elastic layer 100 having a relatively stable degree of storage modulus change in a wide temperature range. The lifting phenomenon may occur due to a difference in modulus between the elastic layer and a layer in direct contact with the elastic layer during repeated bending and folding, etc. The occurrence of such a lifting phenomenon can be suppressed to a significant level.

The film 190 may be disposed outside the polarizing layer on the light source to protect the light emitting layer 320 (a display device).

The film 190 is on one side of the light emitting layer 300 including the light emitting layer 320 having a light emitting function in the multilayer electronic device 900 and/or the sensor layer 340 having a sensing function such as a touch sensor. Arranged, it can be applied to the purpose of protecting the light emitting functional layer 300 .

4 is a conceptual diagram illustrating the configuration of a multi-layer electronic device according to an embodiment in cross section, and FIGS. It is a conceptual diagram explaining, and FIG. 6 is a conceptual diagram explaining the configuration of a multi-layer electronic device according to an embodiment in cross section. A multi-layer electronic device and the like will be described in detail with reference to FIGS. 4 to 6 .

Multilayer Electronic Equipment(900)

In another embodiment, the multilayer electronic device 900 includes an elastic layer 100 or film 190 .

The multi-layer electronic device 900 may be a display device, for example, a large-area display device, a foldable display device, a bendable display device, or a flexible display device. The multi-layer electronic device 900 may be a bendable mobile communication device (eg, a mobile phone) or a bendable notebook computer.

Specific details of the elastic layer 100 and the film 190 overlap with those described above, and thus description thereof will be omitted.

The multi-layer electronic device 900 may include a film 190 positioned on the light-emitting functional layer 300 .

The light emitting layer 300 includes a light emitting layer 320 .

The light emitting layer 320 includes an element emitting light according to a signal from the display device. The light emitting layer 320 includes, for example, a signal transmission layer 322 that transmits an external electrical signal to the color development layer, a color development layer 324 that is disposed on the signal transmission layer and develops a color according to a given signal, and the color development layer. A protective encapsulation layer 326 may be included. The signal transmission layer 322 may include a thin film transistor (TFT), for example, LTPS, a-SiTFT, or oxide TFT may be applied, but is not limited thereto. Thin film encapsulation (TFE) may be applied to the encapsulation layer 326 , but is not limited thereto.

The emission layer 320 may be disposed on the support layer 380 . The support layer 380 may be a layer having insulating properties and heat resistance properties, for example, a polyimide film, a glass layer, or the like may be applied.

The light emitting functional layer 300 may further include a sensor layer 340 . A touch sensor or the like may be applied as the sensor layer 340 .

The light emitting layer 300 may further include a polarization layer 360 . The polarization layer 360 may be disposed on the emission layer 320 or on the sensor layer 340 .

In the multi-layer electronic device 900 , the elastic layer 100 or the film 190 may be adhered to the light emitting functional layer 300 .

In the multi-layer electronic device 900 , the elastic layer 100 or the film 190 may serve as a cover film to protect the light emitting layer 320 (a display device). In addition, the elastic layer 100 or the film 190 has excellent optical properties and at the same time has excellent elastic recovery over a wide temperature range, and excellent durability, so that the occurrence of a lifting phenomenon in the process of repeated bending and folding is significant. It can be suppressed from the above, so it has excellent utility for use as a window cover or a protective film.

In addition, the elastic layer 100 supplements the protective function (function to protect the inside of the cover film from external impact) that was insufficient with the polyimide film applied as a heat-resistant layer alone, and covers the window using existing glass, etc. It has excellent rolling and bending durability, which has been evaluated as lacking in existing cover windows such as glass, while maintaining the protective function of multi-layer electronic equipment, so it has excellent utility as a cover layer and protective film for multi-layer electronic equipment.

Method of manufacturing the elastic layer 100 or the film 190

The manufacturing method of the elastic layer 100 according to the embodiment comprises the steps of forming a polymer resin into an elastic sheet; and passing the assembly in which the elastic sheet 80 is disposed on the carrier film 92 between rollers to provide the elastic layer 100 .

The polymer resin may include an amide or a residue thereof as a repeating unit. A detailed description of the repeating unit, polymerization, etc. of the polymer resin overlaps with the description given in the above elastic layer, and thus description thereof will be omitted.

The manufacturing method of the film 190 according to the embodiment comprises the steps of forming a polymer resin into an elastic sheet; and passing the assembly in which the elastic sheet 80 is disposed on the carrier film 92 between rollers to provide the elastic layer 100 .

The film 190 manufacturing method further includes an additional layer in which the film 190 is an adhesive layer 130 , 130 ′ other than the elastic layer 100 , a heat resistance layer 120 , and/or a polarization layer 360 . In this case, the step of laminating the elastic layer 100 and the additional layer may be further included.

The polymer resin may be an elastomer that forms an amide residue as a repeating unit. The polymer resin may be an elastic polyamide resin or a polyether block amide resin. As the elastic polyamide resin, PA11, PA12, PA1012, PA1010, PA610, PA612, etc. may be applied. As the polyether block amide resin, PEBAX®, Pebax® Rnew®, VESTAMID® E of Evonik, etc. may be applied.

The polymer resin may be molded in the shape of an elastic sheet. The method of molding into the shape of the elastic sheet may be applied as long as it is a method applied to the production of a film, and a melt extrusion method or the like may be applied. In the case of manufacturing the elastic layer or a film (or laminate) including the same by the melt extrusion method, an elastic layer of excellent quality may be manufactured more efficiently.

When the polymer resin is melt-extruded to form an elastic sheet, the melt-extrusion temperature may be 200 to 300 °C. When melt extrusion is performed in such a temperature range, fluidity is imparted to the polymer resin without impairing the properties of the resin itself, so that it can be smoothly molded into a sheet shape.

The elastic sheet 80 may be disposed on the carrier film 92 .

The sheet laminate 90 including the carrier film and the elastic sheet disposed on the carrier film may be processed into the elastic layer 100 in the form of a film passing through a roller.

As for the roller, a first roll 40 and a second roll 60 may be applied with the sheet laminate 90 interposed therebetween, and the first roll 40 may be a casting roll, and the second roll 60 may be applied. A silver squeezing roll may be applied.

One side of the sheet laminate may be processed to a certain thickness by pressing on a casting roll and the other side of the sheet laminate in contact with a squeezing roll.

If necessary in the processing process, the sheet laminate may further include a sheet protective film 94 . Specifically, the sheet laminate may include a carrier film 92 , an elastic sheet (or elastic layer) disposed on the carrier film, and a sheet protective film 94 disposed on the elastic sheet.

The method of manufacturing the elastic layer may provide an elastic layer controlled to have a preset thickness by manufacturing an elastic sheet having a certain thickness and passing it between rollers. The method of controlling the thickness of the elastic sheet, the method of controlling the thickness of the elastic layer passing between the rollers, etc. are applicable as long as the method is applied in film production, and detailed description thereof will be omitted. In addition, since the detailed description of the thickness of the elastic layer overlaps with the above description, the description thereof will be omitted.

In the process of passing between the rollers, the surface roughness of the elastic layer may be controlled. The surface roughness of one surface of the elastic layer may be controlled by the roughness of the carrier film in direct contact with one surface of the elastic layer. The surface roughness of the other surface of the elastic layer may be controlled by the surface roughness of the squeegee roll in direct contact with the other surface of the elastic layer or the surface roughness of the sheet protective film. The surface roughness of one side and the other side of the elastic layer, the surface roughness of the carrier film, the surface roughness of the sheet protective film, the surface roughness of the squeezing roll, etc. overlap with those described above, and thus description thereof will be omitted.

In the method of manufacturing the film, the elastic layer may be manufactured in the form of an assembly together with the carrier film or the like or the elastic layer itself from which the carrier film is removed.

The method of manufacturing the film may further include removing the carrier film from the assembly, if necessary.

The method of manufacturing the film may further include disposing an adhesive layer on one side or the other side of the elastic layer, if necessary.

The method of manufacturing the film may further include disposing a heat-resistant layer on one side or the other side of the elastic layer, if necessary. The heat-resistant layer may be a polyimide layer or a glass layer.

The heat-resistant layer may be adhered directly to the elastic layer or through an adhesive layer disposed separately.

The method of manufacturing the film may further include a hard coating layer disposed on one side or the other side of the elastic layer. The process of forming the hard coating layer may be applied without limitation as long as it is a method of forming a hard coating layer on the display protective film.

The method of manufacturing the film may further include a polarizing plate disposed on one surface or the other surface of the elastic layer. An adhesive layer may be disposed between the elastic layer and the polarizing plate, a heat-resistant layer may be disposed, and the adhesive layer and the heat-resistant layer may be disposed together.

Specific descriptions of the film, the elastic layer, the use thereof, etc. will be omitted since they overlap with those described above.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example: Preparation of elastic layer and evaluation of physical properties

Preparation of polymer resin

The resin applied to the Example or Comparative Example of the film including the elastic layer was prepared as follows.

- PEBA (polyether block amide) resin

Arkema Pebax® 2533 (PEBA Resin 1), Arkema Pebax® 5533 (PEBA Resin 2), Arkema Pebax® 7033 (PEBA Resin 3), Arkema Pebax® Rnew® 55R53 (PEBA Resin 4), Arkema Pebax® Rnew® 63R53 (PEBA) Resin 5), Arkema Pebax® Rnew® 70R53 (PEBA resin 6), Arkema Pebax® Rnew® 72R53 (PEBA resin 7), Arkema Pebax® Rnew® 80R53 (PEBA resin 8), etc. were obtained from Arkema, France and used in the experiment below. applied.

- PA (Polyamide) resin

PA610 (PA resin 1), PA612 (PA resin 1), PA1010 (PA resin 3), PA1012 (PA resin 4), PA12 (PA resin 5), AESNO TL (PA resin 6), PA11 (PA resin 7), etc. was obtained from Arcema, France and applied to the experiment below.

- TPU film, PET film

TPU was applied by purchasing Argotec's 46510 film (Alipatic TPU). PET film NRF manufactured by SKC was applied.

Preparation of elastic layer

It was put in the extruder and melt-kneaded, and then the elastic sheet was extruded into a single-layer sheet. At this time, the melt-kneading temperature was applied to about 220 ℃ in the case of PEBA resin 7, and proceeded by controlling the melt-kneading temperature in the range of about 200 to 300 ℃ according to each resin. The prepared single-layer elastic sheet was placed on a single carrier film (PET film with a thickness of 50 μm to 250 μm. The PET film had a Ra of 0.001 to 0.01 μm) in a continuous process to form an assembly, and the assembly was A laminate including an elastic layer was prepared while passing between the casting roll and the squeezing roll heated to a temperature of 120 °C. After removing the carrier film, the elastic layer of about 100 um in thickness was evaluated as the film of the following Examples and the physical properties below.

A film prepared by the same method and thickness as above without applying a carrier film was evaluated as a film of Comparative Example below to evaluate physical properties.

Evaluation of the properties of the elastic layer

1) Evaluation of storage modulus

According to ASTM D4065, storage modulus (Storage Modulus, E') was evaluated by applying the DMA Q800 model of TA instruments. Table 1 shows the results of measuring the storage modulus (E') in Mpa in the temperature section (-40 to 80 °C) by applying 1Hz, 2 °C/min in the DMA (Dynamic Mechanical Analysis) tension mode to the device. . Amplitude of 5um was applied, and pre-force of 0.01N was applied.

Together with the above, the results of evaluating the storage modulus in the same manner as above by applying the PET film and the TPU film are presented. The PET film is a 50 um thick NRF film manufactured by SKC, and the TPU is an Argotec 46510 monolayer film with a 100 um thickness.

All sample films were subjected to the above evaluation after conditioning for 15 days in an atmosphere of 23°C and 50%RH.

2) Evaluation of surface properties and optical properties

The surface roughness was evaluated according to ASTM D4417 standard using the SJ-310 model of MITUTOYO.

Haze was measured according to the ISO 14782 standard using a haze meter NDH-7000N manufactured by Nippon denshoku, Japan.

Y.I (Yellow Index) was measured in YI E313 (D65/10) mode by applying a color meter ultra scanpro manufactured by Hunterlab. When the measured value was 1 or less, it was evaluated as Pass, and when it was more than 1, it was evaluated as Fail.

Delta-YI measures the YI of the film before and after exposure to UV light for 72 hours with an output of 3.0 W using a UVB Lamp (SANKYO DENKI G15T8E, 280-360 nm wavelength), and subtracts the YI before exposure from the YI after exposure. indicated.

3) Evaluation of recovery ability

An 80mm x 25mm film was fixed using a jig at both ends of the film at 15mm, and the length of the film to which the stress is applied was set to 50mm x 25mm. A tensile test was performed after 100 cycles of 1 cycle to restore the film to its original length at a rate of 50 mm/min after pulling 2% of the film at a rate of 50 mm/min. After 100 cycles, the length (Xf) between the jigs of the film was measured and compared with the length (Xo, 50 mm) between the jigs of the initial film, the number of recovery was evaluated according to Equation 2 below.

[Equation 2]

In Equation 2 above,

Xo is the length of the initial elastic layer (mm),

X _2% is the length (mm) after stretching the elastic layer by 2%,

Xf is the length (mm) of the elastic layer after 100 cycles of 2% stretching at a rate of 50 mm/min and restoration to the original length at a rate of 50 mm/min as one cycle.

4) Dynamic bending evaluation

Dynamic folding test was performed according to IEC 62715-6-1 standard. The film was checked for cracks after 200,000 times of dynamic bending test at -40°C with a radius of curvature of 2 mm and a bending degree of 2 seconds/time. A case in which cracks occurred was evaluated as Fail, and a case in which cracks did not occur by visual observation was evaluated as Pass.

E' (Mpa) -40 0 20 40 80 PA resin 1 2211 1920 1692 914 327 PA resin 2 2109 1820 1605 921 306 PA resin 3 1652 1458 1324 832 249 PA resin 4 1510 1299 1163 751 193 PA resin 5 1365 1185 1120 1050 900 PA resin 6 1965 1762 1579 1067 274 PA resin 7 1567 1368 1260 949 220 PEBA resin 1 238 54 12 11 5 PEBA Resin 2 656 214 149 119 73 PEBA resin 3 1370 843 487 300 170 PEBA resin 4 520 200 142 106 55 PEBA Resin 5 1284 734 463 265 168 PEBA Resin 6 1467 1087 781 406 210 PEBA Resin 7 540 430 374 270 119 PEBA Resin 8 600 480 432 360 130 Other Resin 1 (PET) 4450 4035 3889 3727 3084 Other Resin 2 (TPU) 2356 1250 480 88 3 E' (Mpa) R _-40/20 ** R _80/20 ** D _-40-20 *** K _SM * - PA resin 1 1.31 0.19 519 100.30 - PA resin 2 1.31 0.19 504 96.09 - PA resin 3 1.25 0.19 328 61.69 - PA resin 4 1.30 0.17 347 57.58 - PA resin 5 1.22 0.80 245 196.88 - PA resin 6 1.24 0.17 386 66.98 - PA resin 7 1.24 0.17 307 53.60 - PEBA resin 1 19.83 0.42 226 94.17 - PEBA Resin 2 4.40 0.49 507 248.40 - PEBA resin 3 2.81 0.35 883 308.23 - PEBA resin 4 3.66 0.39 378 146.41 - PEBA Resin 5 2.77 0.36 821 297.90 - PEBA Resin 6 1.88 0.27 686 184.46 - PEBA Resin 7 1.44 0.32 166 52.82 - PEBA Resin 8 1.39 0.30 168 50.56 - Other Resin 1 (PET) 1.14 0.79 561 444.88 - Other Resin 2 (TPU) 4.91 0.01 1876 11.73 -

* The storage modulus index K _SM is expressed by Equation 1 below.

[Equation 1]

** The high-temperature storage modulus ratio R _80/20 is expressed by Equation 1-a below.

[Formula 1-a]

** The low-temperature storage modulus ratio R _-40/20 is expressed by Equation 1-b below.

[Formula 1-b]

*** The difference in low-temperature storage modulus is expressed by Equation 1-c below.

[Formula 1-c]

In the above equations, SM _n is the storage modulus (Mpa) measured at a temperature of n °C.

One-sided surface roughness Ra, um Riding surface roughness Ra, um Haze (%) Y.I. PA resin 7 0.0019 0.007 0.5 Pass PEBA Resin 2 0.0023 0.012 One Pass PEBA resin 4 0.0021 0.01 0.8 Pass PEBA Resin 7 0.002 0.008 0.6 Pass Other Resin 1 (PET) 0.0016 0.0018 0.4 Pass Other Resin 2 (TPU) 0.57 0.68 1.4 Pass comparative example 0.01 to 1 0.1 to 2 50 to 90 Pass delta Y.I. number of recovery* Dynamic bending evaluation - PA resin 7 0.5 60 pass - PEBA Resin 2 0.6 88 pass - PEBA resin 4 0.4 82 pass - PEBA Resin 7 0.4 75 pass - Other Resin 1 (PET) 1.0 50 fail - Other Resin 2 (TPU) 3.8 90 fail - comparative example 0.5 72 pass -

* The number of recovery is expressed by Equation 2 below.

[Equation 2]

In Equation 2, Xo is the length (mm) of the initial elastic layer, X _2% is the length (mm) after stretching the elastic layer by 2%, and Xf is the length (mm) after stretching the elastic layer by 2% at a rate of 50 mm/min. It is the length (mm) of the elastic layer after 100 cycles, assuming that it is restored to its original length at a rate of 50 mm/min as one cycle. The length of the elastic layer means the length between the fixing parts (jigs).

Referring to Table 1 and Table 2, the prepared elastic layers all showed a lower haze value compared to the elastic layer of Comparative Example, which is considered to be somewhat related to the surface roughness value.

In Delta-Y.I, the PA or PEBA-applied example showed superior results compared to other resins. In particular, the results of Examples are excellent results compared to other resin 1, which is a PET film, but superior results are also excellent compared to other resin 2 to which TPU is applied. In addition, considering that TPU applied with other resins is the result of applying Aliphatic TPU, which is known to have superior UV durability than aromatic TPU, it was evaluated to have superior UV durability compared to the films of Examples.

In the dynamic bending evaluation conducted at -40 ℃, both the other resin 1 and the other resin 2 were evaluated as fail, so the film of the other resin has insufficient characteristics to be applied for bending or folding in a wide temperature range including low temperatures. confirmed

In the case of the recovery number, although there were variations in physical properties depending on the applied resin, the overall PEBA film or PA film example showed excellent results, and the PEBA film showed better results than the PA film.

As for the number of recovery, the films of Examples were somewhat inferior to the films of Other Resin 2 to which the TPU film was applied, or showed physical properties equal to or higher than the same level. On the other hand, UV durability (yellowing properties) and dynamic bending evaluation results at low temperatures showed superior results for the films of Examples compared to the TPU film.

Considering these characteristics, the elastic layer or the film including the same of the embodiment is considered to be excellent in utility in a foldable display in which repeated bending or folding is performed in a wide temperature range from low to high temperature.

Example: Preparation of film and evaluation of physical properties

preparation of the film

Preparation of cover film specimen: On a 50 um thick transparent polyimide film (manufactured by SKC), 3M's commercially available OCA of 100 um thickness (the difference between the storage modulus measured at -40 degC and the storage modulus measured at +80 degC was -100 to +100 kPa) was used as an adhesive layer, and the 100 um-thick elastic layer (film made of PEBA resin 7) prepared above was laminated on the adhesive layer, and the cover film of Example 1 A specimen was prepared (structure (b) of FIG. 2).

A cover film specimen was prepared in the same manner as the cover film of Example 1, except that the types of elastic layers were applied as shown in Table 4 below, respectively, to Example 2 and Comparative Example 1.

Measurement of film properties

1) Evaluation of tensile impact strength

The tensile-impact strength of the elastic layer was evaluated according to JIS K 7160 standard. The measurement temperature was 23degC, 0 50% RH, the measurement condition was a pendulum of 4.0J, and the resonance angle was applied to 150deg to measure the impact strength and absorbed energy, and the results are shown in the table below. 3 is shown.

2) Bending/bending evaluation of laminated film, pen-drop evaluation

Dynamic folding test: According to IEC 62715-6-1, using a protective film specimen, apply a radius of curvature of 2 mm and a degree of bending of 2 sec/time for a total of 200,000 tests, and if lifting occurs, X, if there was no excitation, it was marked as O. The results are shown in Table 4 below.

Static bending test: Using a protective film specimen, according to IEC 62715-6-1, a test was performed with a radius of curvature of 2 mm, and after 24 hours, if lifting occurred, X, if not, O was indicated. The results are shown in Table 4 below.

Pen drop evaluation: When the pen was dropped from a height of 9 cm onto the laminated film sample, it was evaluated as pass if it was good, and as fail if the film was broken.

Transmittance/Haze: Transmittance and haze were measured with NDH7000 (manufactured by Denshoku, Japan). If the haze was 1% or less, it was evaluated as Pass, and if it was more than 1%, it was evaluated as Fail. As for the transmittance, the case where the transmittance in visible light was 90% or more was evaluated as Pass, and the case where it was less than 90% was evaluated as Fail.

Impact strength (kJ/m ² ) Absorbed energy (J) Other Resin 1 (PET) 2900 1.43 Other Resin 2 (TPU) 1900 1.05 PEBA Resin 7 5400 1.66

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Structure of the film laminate 7 layers of PEBA resin + adhesive layer + PI film TPU layer + adhesive layer + PI film PET layer + adhesive layer + PI film PI film sole Dynamic bending evaluation -40degC Pass Fail Fail - 80degC Pass Pass Fail - Static bending evaluation -40degC Pass Pass Fail - 80degC Pass Pass Fail - pen drop rating 9cm Pass Pass Pass Fail Transmittance (%) Pass Pass Pass Pass Haze (%) Pass Pass Pass Pass

Referring to Table 3, the impact strength of the example film to which PEBA resin 7 is applied is significantly higher than the impact strength of the film to which other resin 2 (TPU) is applied or the impact strength of the film to which other resin 1 (PET) is applied. It was confirmed that it has very strong properties. In the case of absorption energy, the case of the Example film to which PEBA resin 7 was applied was significantly superior to the case of the film to which other resin (TPU) was applied or the film to which other resin 1 (PET) was applied.

This shows that TPU is superior to PET in terms of storage modulus-related properties salpin above, but TPU has properties inferior to PET in terms of tensile impact strength properties. In addition, the results show that the film to which PEBA is applied has excellent storage modulus properties and tensile impact strength properties.

Referring to Table 4, the laminate of Example 1 to which the PEBA resin 7 prepared above is applied is a pass in all aspects of dynamic bending evaluation at low and high temperatures, static bending evaluation at low and high temperatures, pendrop evaluation, transmittance, and haze It was evaluated to be excellent in all of the measured physical properties. On the other hand, Example 2 applying the same adhesive layer and PI film as in Example 1 but applying TPU instead of PEBA resin 7 has all other properties excellent, but is evaluated as Fail in low-temperature dynamic bending evaluation, repeated bending at low temperature It was evaluated that lifting, etc. may occur when it occurs. On the other hand, Comparative Example 1 to which PET was applied was evaluated as Fail in both dynamic and static bending evaluation, and was evaluated to have properties difficult to apply as a bendable or rollable cover film. Comparative Example 1 is the result of testing the polyimide film alone, and it was evaluated as Fail in the pendrop evaluation, and it was evaluated that it is difficult to obtain the effect of impact protection as a cover film with the polyimide film alone.

Although the preferred embodiment of the present invention has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

100: elastic layer
100a: one surface of the elastic layer 100b: the other surface of the elastic layer
120: heat-resistant layer 130, 130': adhesive layer
140: hard coating layer 150: release film
80: elastic sheet 92: carrier film
94: sheet protective film 40: first roll, casting roll
60: second roll, squeezing roll 90: sheet laminate
190: film, film laminate
300: light emitting functional layer
320: light emitting layer 322: signal transmission layer
324: color development layer 326: encapsulation layer
340: sensor layer 360: polarization layer
380: support layer 900: multi-layer electronic equipment

Claims (23)

comprising an elastic layer;
The elastic layer has a storage modulus index K _SM of 20 to 350 Mpa, which is expressed by Equation 1 below,
The elastic layer has a haze of 3% or less, a film;
[Equation 1]

In Equation 1, SM _n is the storage modulus (Mpa) measured at a temperature of n °C.
According to claim 1,
The elastic layer has a storage modulus of 3 GPa or less at room temperature, the film.
According to claim 1,
The elastic layer has a storage modulus ratio of 0.08 or more at 80 °C based on the storage modulus at 20 °C.
According to claim 1,
The elastic layer has a storage modulus at -40 ° C and a storage modulus at 20 ° C. The difference is -1500 to +1500 MPa, the film.
According to claim 1,
The elastic layer has a storage modulus of 20 to 2500 Mpa at 0 °C, the film.
According to claim 1,
The elastic layer has a storage modulus of 5 Mpa or more at 80 °C, the film.
According to claim 1,
The elastic layer is less than 2000 um in thickness, the film.
According to claim 1,
The elastic layer is a recovery force index Rv represented by the following formula 2 is greater than 50, a film;
[Equation 2]

In Equation 2, Xo is the length (mm) of the initial elastic layer, X _2% is the length (mm) after stretching the elastic layer by 2%, and Xf is the length (mm) after stretching the elastic layer by 2% at a rate of 50 mm/min. It is the length (mm) of the elastic layer after 100 cycles, assuming that it is restored to its original length at a rate of 50 mm/min as one cycle.
comprising an elastic layer;
The elastic layer is a recovery force index Rv represented by the following formula 2 is greater than 50, a film;
[Equation 2]

In Equation 2, Xo is the length (mm) of the initial elastic layer, X _2% is the length (mm) after stretching the elastic layer by 2%, and Xf is the length (mm) after stretching the elastic layer by 2% at a rate of 50 mm/min. It is the length (mm) of the elastic layer after 100 cycles, assuming that it is restored to its original length at a rate of 50 mm/min as one cycle.
10. The method of claim 9,
The roughness reference value is the larger of Ra1, which is the surface roughness Ra value of one side, and Ra2, which is the surface roughness Ra value of the other side,
The elastic layer has a roughness reference value of 0.5 um or less, the film.
10. The method of claim 9,
The film or the elastic layer has a value obtained by subtracting the yellowness before exposure from the yellowness after exposure for 72 hours with an output of 3.0 W to ultraviolet rays of a wavelength of 280 to 360 nm is 2 or less.
10. The method of claim 9,
The elastic layer is a film comprising a polymer including an amide residue as a repeating unit.
10. The method of claim 9,
The elastic layer is a polyamide, polyether block amide (polyether block amide, PEBA), thermoplastic polyurethane (thermoplastic polyurethane, TPU), polyether ester copolymer (copolyetherester, COPE), or a film comprising a mixture thereof.
10. The method of claim 9,
The elastic layer has an ^{impact strength of 2500 kJ / m 2} or more or an absorption energy of 1.4 J or more, a film.
15. The method of claim 14,
The elastic layer is disposed on the heat-resistant layer, the film.
16. The method of claim 15,
The heat-resistant layer includes a polyimide layer or a glass layer,
The haze of the heat-resistant layer is 3% or less, the film.
16. The method of claim 15,
Further comprising an adhesive layer disposed on one or both surfaces of the heat-resistant layer,
The adhesive layer has a difference between the storage modulus at -40 ℃ and the storage modulus at 80 ℃ is -100 to +100 kPa, the film.
18. The method of claim 17,
A film that does not float even after 200,000 dynamic folding tests under the conditions of a 2 mm radius of curvature and a bending frequency of 2 seconds/time.
Forming an elastic sheet from a polymer resin containing an amide or a residue thereof as a repeating unit; And
Including; passing the first assembly on which the elastic sheet is disposed on the carrier film between rollers to provide a second assembly including an elastic layer positioned on the carrier film;
10. A method for producing a film according to claim 1 or 9, for producing a film.
20. The method of claim 19,
The carrier film has a surface roughness of a surface in contact with the elastic sheet of 0.01 um or less, a method of manufacturing a film.
A cover film comprising the film according to any one of claims 1 to 16.
A multilayer electronic device comprising the film according to any one of claims 1 to 16 as a cover film.
23. The method of claim 22,
Containing a light-emitting functional layer and the cover film,
The light emitting functional layer has a display area that emits or does not emit light according to an external signal,
wherein the cover film is disposed on one surface of the light emitting functional layer and covers at least a portion of the display area.

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