KR20160045292A - Complex film having high heat resistance, fabrication method thereof and use of the same - Google Patents

Abstract

The present invention relates to a highly heat resistant composite film, a production method thereof, and a use thereof. More specifically, the present invention relates to a highly heat resistant composite film having a structure in which a discontinuous buffering pattern is embedded on a polymeric base material film. The discontinuous buffering pattern contains a buffer material having the lower coefficient of thermal expansion (CTE) than the polymeric base material film. The present invention further relates to a production method thereof, and a use thereof. The highly heat resistant composite film barely shows thermal contraction or expansion of a polymer in accordance with a temperature change, resulting in the minimization in the value which varies by the heat application. Thus, the film of the present invention can be applied to highly reliable crucial heat-resistant materials in the high-tech industries such as electric-electronic fields and the aerospace industries. For instance, the film can be used as a substrate of a flexible display.

Description

TECHNICAL FIELD The present invention relates to a high heat resistant composite film, a method of producing the same, and a use thereof,

TECHNICAL FIELD The present invention relates to a high heat resistant composite film in which a change in numerical value due to heat is minimized, a method for producing the composite film, and a use thereof.

Flexible displays are advantageous in terms of portability, stability, and light weight by using a flexible plastic substrate as a substrate.

In this case, the plastic substrate used is lightweight compared to metal foil and glass, is resistant to impact, is easy to process and has almost no restriction on shape / thickness, and has a roll-to- -roll process), it received industrial attention from the early days of development of flexible display.

Plastic substrate materials require properties such as high temperature stability, low thermal expansion coefficient, high gas permeation prevention characteristics, excellent chemical resistance, low optical anisotropy, scratch resistance, excellent surface flatness, humidity stability, substrate transferability and low cost As a result, highly heat-resistant engineering plastics are used.

Currently developed plastic substrate materials are being performed to secure the characteristics of the materials themselves, and in particular, there are many processes in which a display manufacturing process is exposed to heat, so that researches on substrates having high temperature stability are actively conducted.

When the plastic substrate is heated to a certain high temperature and then cooled to room temperature, the substrate expands at a high temperature and shrinks when the temperature is cooled to room temperature. As a result, the shape of the substrate may be deformed, (For example, electrode wiring, etc.) is generated.

Shrinkage and expansion due to such temperature are a major obstacle to the process application of the plastic substrate, and a method for improving the heat resistance of the plastic substrate is required.

The heat resistance, that is, the high temperature stability, is closely related to the thermal expansion coefficient of the substrate, and if the thermal expansion is large as the temperature rises, the precision of the process is likely to be threatened. Since the thermal properties and the thermal expansion coefficient are determined by the material characteristics, a high performance film material with a new structure, a film forming process, and materials capable of mass production are being developed.

As a method for improving heat resistance, it is possible to change the composition of a polymer base film itself used as a substrate, to synthesize a heat-resistant polymer having a new structure, to produce a film after melting inorganic fibers (e.g., glass fiber) and polymer, A method of coating with other excellent compositions has been proposed.

For example, in Korean Patent Laid-Open Publication No. 2011-0065077, inorganic precursors such as silicon (Si), titanium (Ti), tantalum (Ta), and aluminum (Al) are coated by a chemical vapor deposition And a substrate on which an inorganic oxide is laminated on a film. The patent discloses that cracks or defects can be prevented from occurring in the inorganic thin film due to the difference in thermal expansion coefficient between the polymer film and the inorganic thin film, thereby ensuring the stability of the plastic substrate.

Korean Patent Laid-Open Publication No. 2011-0083334 discloses a touch screen substrate on which an ITO thin film is coated on a transparent and flexible substrate, and a heat resistant polymer such as Teflon is deposited as a buffer layer between the substrate and the ITO thin film, It is possible to prevent lifting and cracking of the ITO thin film during the process.

These patents have not been sufficient to overcome thermal shrinkage and expansion problems of the substrate, although they have been presented in the form of multilayer structures in which layers of different materials are laminated as measures to increase the heat resistance of the substrate.

On the other hand, Korean Patent Registration No. 10-1191865 discloses a flexible substrate having a metal wiring recessed therein. In this case, the metal wiring pattern has a structure connected to the entire flexible substrate, It is possible to form a wiring with a low resistance without being restricted by the height of the metal wiring by forming it into a form embedded in a flexible substrate.

Korean Patent Publication No. 2011-0065077 Korean Patent Publication No. 2011-0083334 Korean Patent Registration No. 10-1191865

Therefore, the present applicant has found that a material having a coefficient of thermal expansion (CTE) lower than that of a polymer film, which is a base film of a substrate, is selected and embeded or embedded in a predetermined pattern instead of being coated on the polymer base film ) Was introduced to prepare a composite film, and it was confirmed that the heat shrinkage and expansion of the polymer due to the temperature change hardly occur in the composite film, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a high heat-resistant composite film in which a change in numerical value by heat is minimized.

Another object of the present invention is to provide a method for producing the high heat resistant composite film.

Still another object of the present invention is to provide the use of the high heat resistant composite film.

In order to accomplish the above object, the present invention provides a polymer base film having a structure in which a discontinuous buffer pattern is embedded, wherein a coefficient of thermal expansion (CTE) is lower than that of the polymer base film of the discontinuous buffer pattern Heat-resistant composite film comprising a buffer material having a high heat resistance.

At this time, the discontinuous buffer pattern is characterized in that a plurality of branches extend from the center point, and the adjacent branches extend to have the same angle.

In addition, the discontinuous buffer pattern has 3 to 8 branches, each branch having an angle in the range of 45 to 120 degrees with respect to each other.

Further, the thickness ratio of the polymer base film to the discontinuous buffer pattern is in the range of 1: 0.20 to 1: 0.95.

At this time, the high heat resistant composite film according to the present invention

S1) providing a polymer base film,

S2) etching the polymer base film to form an engraved pattern, and

S3) filling the buffer pattern with the buffer pattern to form a discontinuous buffer pattern having a structure in which the buffer material is embedded in the polymer base film.

Further, the present invention is characterized by using the high heat resistant composite film as a substrate of a flexible display.

The heat-resistant composite film according to the present invention is a highly reliable core heat-resistant material of high-tech industries such as optical, semiconductor, electric / electronic, biosensor, solar energy, and aerospace because heat shrinkage and expansion of the polymer hardly occurs And can be used as a substrate of a flexible display, for example.

1 is a front view (a) of a high heat resistant composite film according to the present invention, and Fig. 1 (b) is a sectional view thereof.
2 is a flow chart showing a process for producing a high heat resistant composite film according to the present invention.
Fig. 3 is a cross-sectional view of the pattern (a) and (b) of the composite film produced in Examples 1 to 6;

In the present invention, a high heat resistant composite film which can be applied to various fields without shrinkage and expansion due to temperature changes is proposed.

1 is a front view (a) of a high heat resistant composite film according to the present invention, and Fig. 1 (b) is a sectional view thereof.

Referring to Fig. 1, the high heat-resistant composite film 5 has a structure in which the discontinuous buffer pattern 3 is embedded on the polymer base film 1. Fig. The discontinuous cushioning pattern 3 is made of a buffer material having a relatively low CTE (thermal deformation coefficient) as compared with a polymer, and has a thermal stress applied to the base film 1 through a structure embedded in the base film 1 Thereby minimizing heat shrinkage or deformation. The structure in which the pattern (3) is embedded can simplify or disperse the buffer material to the polymer base film (1) itself or more effectively relax the thermal stress compared with a simple laminated structure.

Specifically, the discontinuous cushioning pattern 3 is formed to have a structure capable of relieving the stress most stably. Specifically, the discontinuous cushioning pattern 3 has a structure in which a plurality of branches extend from the center point, and the adjacent branches extend to have the same angle.

For example, as shown in Fig. 1, the discontinuous buffer pattern 3 has three branches, one branch being located vertically from the center point, and another branch extending at an angle of 120 [deg. Shaped pattern in which another branch which extends at an angle of 120 DEG to the lower right is located.

As another example, when there are four branches, the discontinuous cushioning pattern 3 has a cross shape in which four branches extend from the center point, and these branches extend at an angle of 90 DEG with respect to each other.

Another example is a structure in which six branches extend at an angle of 60 DEG from the center point, or a structure in which eight branches extend at an angle of 45 DEG from the center point.

The number of the branches is not limited to the present invention, and the angle formed by the branches varies depending on the number of branches.

The discontinuous cushioning pattern 3 defines dimensions in order to suppress the shrinkage and expansion of the polymer base film 1 in accordance with the temperature change as much as possible. Preferably, the branch has a length of 10 μm to 1,000 μm, preferably 50 μm to 200 μm, a width of 5 μm to 500 μm, preferably 10 μm to 200 μm, a distance between patterns of 10 mm to 1000 mm , Preferably 100 mm to 500 mm. At this time, the dimension of the branch may be varied depending on the use of the high heat resistant composite film 5 and the dimension of the polymer base film 1.

Particularly, it is essential to control the thickness ratio of the polymer base film 1 and the discontinuous buffer layer 3, and preferably the thickness ratio is in the range of 1: 0.20 to 1: 0.95, preferably 1: 0.50 to 1: 0.90 . In general, the thickness of the polymer base film 1 may be 10 탆 to 1,000 탆, preferably 50 탆 to 500 탆. For example, when the thickness of the polymer base film 1 is 100 m, the discontinuous buffer pattern 3 may have a thickness of 20 m or more, 95 m or less, preferably 90 m, The inner depth discontinuous buffer pattern 3 can be inherent.

If the thickness of the discontinuous cushioning pattern 3 is too thin (that is, when the thickness ratio is outside the thickness ratio range), the heat resistance due to the buffer material can not be sufficiently secured. On the contrary, It is difficult to obtain a clean pattern because the material is not easily filled, and the polymer base film (1) may be short-circuited.

Referring to Experimental Example 1 of the present invention, in the case of a polymer composite film in which a discontinuous buffer pattern is incorporated (Example 1), a thermal deformation stress is reduced by about 88% or more as compared with a simple stacked laminated film (Comparative Example 1) From these results, it can be seen that the composite film having the discontinuous buffer pattern has better heat resistance than the simple laminated structure.

2 is a flow chart showing a process for producing a high heat resistant composite film according to the present invention.

Referring to FIG. 2, the production of the high heat resistant composite film (5) according to the present invention

S1) providing a polymer base film (1)

S2) etching the polymer base film (1) to form engraved pattern (3a), and

S3) filling the buffer pattern 3a with a buffer material to form a discontinuous buffer pattern 3 having a structure in which the buffer material is embedded in the polymer base film 1;

Each step will be described in more detail below.

First, a polymer base film 1 is prepared (step S1, Fig. 2 (a)).

The polymer base film (1) is not particularly limited in the present invention, and all known thermoplastic resins and thermosetting resins can be used.

Examples of the thermoplastic resin include general-purpose plastics such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, styrene-acrylonitrile (SAN) resin, ABS (acrylonitrile butadiene styrene) resin, ethylene- (COP), cycloolefin co-polymer (COC), polyimide (PI), polyamide (PA), modified triacetyl cellulose (TAC), polyethylene terephthalate (PET), polysulfone (PSF), polyethylene sulfone ), Polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polycarbonate (PC), polymethylmethacrylate (PMMA), ethylene vinyl acetate (EVA), polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polyethylene terephthalate glycerol (PETG), polycyclohexylenedimethylene terephthalate (PCTG), dicyclopentadiene polymer (DCPD), cyclopentadiene Polyetheretherketone (PEEK), polyetherimide (PEI), polyamideimide (PAI), polydimethylsilonane (PDMS), polyetheretherketone (PEEK), polyetherketone Of engineering plastics are possible.

Examples of the thermosetting resin include phenol resin, polyurethane, epoxy resin, amino resin, melamine resin, silicone resin, Teflon resin, and polybenzimidazole.

The material of the polymer base film depends on the use of the composite film of the present invention. For example, when applied to a substrate of a flexible display requiring high heat resistance, an engineering plastic such as a cycloolefin polymer or polyimide is used.

Next, the polymer base film 1 is etched to form the engraved pattern 3a (S2, Fig. 2 (b)).

At this time, the engraved pattern 3a has the same shape as the discontinuous cushioning pattern in which a plurality of branches extend from the above-mentioned center point.

The etching can be performed by any known dry etching, wet etching or pressing process, and is not particularly limited in the present invention.

For example, dry etching can be performed using a laser, a plasma, an ion beam, or an etching gas, or a wet etching process using an etchant such as HF.

The pressing process can obtain the pattern by pressing the polymer base film 1 onto the mold having the pattern of the embossed pattern.

Next, a high-temperature-resistant composite film 5 is prepared by filling a buffer material in the engraved pattern 3a to form a discontinuous buffer pattern 3 having an embeded structure (S3, FIG. 2 c).

The buffer material may be varied depending on the field of application of the polymer base film 1, and any material having a CTE lower than that of the polymer material may be used. Preferably, the buffer material is a conductive material containing a metal or a metal oxide, Can be used.

For example, when the composite film 5 according to the present invention is applied to a substrate of a transparent flexible display, if the conductive material is used as the discontinuous cushioning pattern, the conductive property of the electrode can be further enhanced by acting as a bridge between the electrodes.

The conductive material may be at least one selected from the group consisting of Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, Pd, Ta, Sn, SUS, or an alloy thereof; (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO) oxide), ATO (antimony tin oxide ), GZO (gallium zinc oxide), IrOx, RuOx, TiO 2 , or a conductive oxide may be a combination thereof.

As another example, when the composite film (5) according to the present invention is applied, it is possible to use a nonconductive material as the discontinuous buffer pattern (3). Such a nonconductive material has a sufficient buffering function so that it can have excellent heat resistance.

The nonconductive material may include at least one of Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, Pd, Ga, Ta, Sn, and alloys of these metals.

The thermal expansion coefficients of the polymer, metal and metal oxide are shown in Table 1 below, and each material is selected according to the use of the composite film (5) based on such data ("Axiomatic design and fabrication of composite structures" , DG LEE, (2006), Oxford university press].

material CTE (ppm / K)


Polymer


COP 72 nylon 50 to 90 Polycarbonate (PC) 65 Polyetheretherketone (PEEK) 25 to 50 Polyetherimide (PEI) 45 Polyphenylene sulfide (PPS) 50 Epoxy 29 Polybenzimidazole 25 Teflon 135 Conductive material Al 24 Ti 8.9 ITO 4.3 Nonconductive material Alumina 0.6

In this step, various methods such as a known dry coating method or wet coating method can be used to fill the buffer material.

Examples of the dry coating method include electron beam evaporation, induction heating evaporation, laser beam evaporation, sputtering, magnetron sputtering, ion beam sputtering, ion plating, and ion beam evaporation.

As the wet coating method, slurry coating, dip coating, spray coating, air plasma coating, printing, spin coating and the like are possible.

The filling by the dry or wet coating method may vary depending on the material used as the buffer material and may be varied by a person skilled in the art.

For example, when a metal such as copper is used as the buffering material, the discontinuous buffer pattern 3 can be obtained by filling the depressed pattern 3a with the buffer material through a dry coating process such as normal sputtering.

When a metal oxide is used as a buffer material, the solution is prepared in the form of a precursor together with a binder, then injected into the engraved pattern 3a, and the polymerization reaction of the precursor proceeds to form a discontinuous buffer pattern 3 ) Can be obtained.

The metal oxide may be applied in the form of an oxide other than a precursor. The slurry may be prepared by mixing the metal oxide particles with a binder, and then injected into the engraved pattern 3a to cure the binder to obtain a discontinuous cushioning pattern 3 .

The heat resistant composite film obtained through the above steps can effectively prevent heat shrinkage or expansion of the polymer base film caused by external temperature or heat since the buffer material is present in the polymer base film as an inherent structure instead of being laminated. This heat-resistant composite film can be applied to any area where heat resistance is required. It can be applied to all fields that can be used as high-reliability core heat-resistant materials in high-tech industries such as optical, semiconductor, electric and electronic, biosensor, It is applicable.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims. In the following, "%" and "part" representing the content are on a mass basis unless otherwise specified.

Example  1: Production of composite film

A laser was applied to a COP film having a thickness of 50 mu m to obtain a sheath pattern. ITO was deposited thereon to form a buffer pattern (thickness: 45 mu m, length: 50 mu m, width: 10 mu m).

Example  2: Preparation of composite film

A laser beam was applied to a COP film having a thickness of 70 mu m to obtain a sheath pattern, and ITO was deposited thereon to form a buffer pattern (thickness: 45 mu m, length: 50 mu m, width: 10 mu m).

Example  3: Preparation of composite film

A laser was applied to a COP film having a thickness of 50 mu m to obtain a sheath pattern. Ti was deposited thereon to form a buffer pattern (thickness: 45 mu m, length: 50 mu m, width: 10 mu m).

Example  4: Preparation of composite film

A laser was applied to a COP film having a thickness of 70 mu m to obtain a sheath pattern, and Ti was deposited thereon to form a buffer pattern (thickness 45 mu m, length 50 mu m, width 10 mu m).

Example  5: Preparation of composite film

And the laser is applied to the 50㎛ COP film thickness to obtain a siot-like pattern, and then coating the SiO ₂ slurry composition herein, by performing a curing process underlying the buffer pattern (thickness 45㎛, 50㎛ length, width 10㎛) . As the slurry composition, 50 nm SiO ₂ and acrylic binder resin were mixed at a weight ratio of 1: 9.

Example  6: Preparation of composite film

And the laser is applied to the 50㎛ COP film thickness to obtain a siot-like pattern, and then coating the TiO ₂ slurry composition herein, by performing a curing process underlying the buffer pattern (thickness 45㎛, 50㎛ length, width 10㎛) . At this time, as the slurry composition, TiO ₂ of 50 nm and an acrylic binder resin were mixed at a weight ratio of 1: 9.

Comparative Example  1: Production of laminated film

ITO (10 mu m) was deposited on a 50 mu m thick COP film to obtain a laminated film (see Fig. 4).

Comparative Example  2: Production of laminated film

ITO (10 mu m) was deposited on a 75 mu m thick COP film to obtain a laminated film.

Comparative Example  3: Production of laminated film

Ti (10 mu m) was deposited on a 50 mu m thick COP film to obtain a laminated film.

Comparative Example  4: Production of laminated film

Ti (10 탆) was deposited on a COP film having a thickness of 75 탆 to obtain a laminated film.

Comparative Example  5: Production of laminated film

The SiO ₂ slurry composition was coated on a COP film having a thickness of 50 탆 and then subjected to a curing process to form a 45 탆 thick SiO ₂ coating layer. As the slurry composition, 50 nm SiO ₂ and acrylic binder resin were mixed at a weight ratio of 1: 9.

Comparative Example  6: Production of laminated film

A TiO ₂ slurry composition was coated on a 50 탆 thick COP film, and then a curing process was performed to form a 45 탆 thick TiO ₂ coating layer. At this time, as the slurry composition, TiO ₂ of 50 nm and an acrylic binder resin were mixed at a weight ratio of 1: 9.

Experimental Example  1: Evaluation of thermal strain stress

The heat distortion stresses of the composite film and the laminated film obtained in the above Examples and Comparative Examples were evaluated.

Experiments were carried out using a dry stress apparatus capable of evaluating the stress due to expansion and contraction of the film. The stresses of each of the above films after being left at 150 캜 for 30 minutes and then cooled at 50 캜 were evaluated, Are shown in Table 2 below. At this time, COP film alone was used as Control Example 1.

Composite film Thermal strain stress (MPa) Example 1 COP / ITO 2.7 Example 2 COP / ITO 2.9 Example 3 COP / Ti 3.1 Example 4 COP / Ti 3.5 Example 5 COP / SiO ₂ 1.7 Example 6 COP / TiO ₂ 2.0 Comparative Example 1 COP / ITO 21.7 Comparative Example 2 COP / ITO 19.2 Comparative Example 3 COP / Ti 27.2 Comparative Example 4 COP / Ti 29.1 Comparative Example 5 COP / SiO ₂ 27.4 Comparative Example 6 COP / TiO ₂ 28.1 Control Example 1 COP 30.1

Referring to Table 2, it was confirmed that the composite film having the cushioning pattern according to the present invention can relieve the stress effectively as compared with the laminated films of Comparative Examples 1 to 6.

In particular, the composite film of Example 1 had a heat distortion stress of 2.7 Ma, and the corresponding evaporated film of Comparative Example 1 had a heat distortion stress of at least about 88%, which was 21.7 Ma, In comparison, 93% or more is reduced and the stress relaxation effect is remarkably excellent.

The heat-resistant composite film according to the present invention can be used as a high-reliability core heat-resistant material in high-tech industries such as optics, semiconductor, electric / electronic, biosensor, solar energy, aerospace and the like and can be preferably used as a substrate of a flexible display .

1: polymer base film 3: discontinuous cushioning pattern
3a: engraved pattern 5: heat-resistant composite film

Claims (12)

The polymeric base film has a structure in which a discontinuous cushioning pattern is embedded,
Wherein the discontinuous cushioning pattern comprises a buffer material having a coefficient of thermal expansion (CTE) lower than that of the polymer substrate film. The high heat resistant composite film according to claim 1, wherein the polymer base film comprises one selected from the group consisting of a thermoplastic resin, a thermosetting resin, and a combination thereof. The high heat-resistant composite film according to claim 1, wherein the discontinuous buffer pattern extends so that a plurality of branches extend from a center point, and neighboring branches have the same angle. 4. The high heat-resistant composite film according to claim 3, wherein the discontinuous buffer pattern has a length of 10 mu m to 1,000 mu m and a width of 5 mu m to 500 mu m. The high heat resistant composite film according to claim 1, wherein the discontinuous buffer pattern is spaced apart from the adjacent pattern by a distance of 10 mm to 1000 mm. The high heat resistant composite film according to claim 1, wherein the high heat resistant composite film has a thickness ratio of the polymer base film: discontinuous buffer pattern of 1: 0.20 to 1: 0.95. The high heat resistant composite film according to claim 1, wherein the buffer material comprises a conductive material. The method of claim 7, wherein the conductive material
Cu, Al, Mo, Sc, Zr, Ru, Pd, Ag, Au, Ga, Ta, Sn, Zn, Cu, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, SUS or an alloy thereof;
(ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO) oxide), ATO (antimony tin oxide ), GZO (gallium zinc oxide), IrOx, RuOx, TiO 2 , or a conductive oxide including a combination thereof; And
And a combination thereof. ≪ RTI ID = 0.0 > 11. < / RTI > The high heat resistant composite film according to claim 1, wherein the buffer material comprises a nonconductive material. The method of claim 9, wherein the nonconductive material is selected from the group consisting of Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ag, Au, Ga, Ta, Sn, and alloys of these metals. Providing a polymeric substrate film,
Etching the polymeric base film to form an engraved pattern, and
The method of manufacturing a high heat-resistant composite film according to claim 1, wherein filling the buffer pattern with the buffer pattern to form a discontinuous buffer pattern having a structure in which the buffer material is embedded in the polymer base film. A substrate for a flexible display comprising the high heat resistant composite film of claim 1.

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