KR102532958B1 - Heating film and method for manufacturing thereof - Google Patents

Abstract

A heating film according to an exemplary embodiment of the present application includes a first adhesive film; a metal foil pattern provided on the first adhesive film; and a resin layer provided in contact with at least a portion of a surface of the metal foil pattern that does not contact the first adhesive film and having a refractive index of 1.45 to 1.49.

Description

Heating film and its manufacturing method {HEATING FILM AND METHOD FOR MANUFACTURING THEREOF}

This application relates to a heating film and a manufacturing method thereof.

When there is a difference between the outside temperature and the inside temperature of the car, moisture or frost occurs on the glass of the car. Heating glass may be used to solve this problem. Heating glass uses the concept of attaching a heating wire sheet to the glass surface or forming a heating wire directly on the glass surface, and generating heat from the heating wire by applying electricity to both terminals of the heating wire, thereby raising the temperature of the glass surface.

In particular, as a method employed to provide a heating function with excellent optical performance to a windshield of a vehicle, there are the following methods.

First, a transparent conductive thin film may be formed on the entire surface of glass. As a method of forming the transparent conductive thin film, there is a method of increasing transparency by using a transparent conductive oxide film such as ITO or by forming a thin metal layer and then using a transparent insulating film on and under the metal layer. This method has the advantage of being able to form an optically excellent conductive film, but has the disadvantage of being unable to implement an appropriate amount of heat at a low voltage due to a relatively high resistance value.

Second, a method of increasing transmittance by maximizing an area without a metal pattern or wire while using a metal pattern or wire may be used. A typical product using this method is a heating glass made by inserting a tungsten wire into a PVB film used for bonding automobile windshields. In the case of this method, the diameter of the tungsten wire used is 18㎛ or more, and it is possible to implement a level of conductivity capable of securing sufficient heat generation at low voltage, but due to the relatively thick tungsten wire, the tungsten wire is easily visible to the naked eye. There are downsides.

Third, a metal pattern may be formed on the PET film through a printing process, or a metal pattern may be formed through a photolithography and etching process after forming a metal layer on the PET film. After inserting the PET film on which the metal pattern is formed between two sheets of PVB film, a heating product having a heating function can be made through a glass bonding process.

Republic of Korea Patent Publication No. 10-2014-0140741

In this specification, a heating film and a manufacturing method thereof are described.

An exemplary embodiment of the present application,

A first adhesive film;

a metal foil pattern provided on the first adhesive film; and

A resin layer provided in contact with at least a part of the surface not in contact with the first adhesive film of the metal foil pattern and having a refractive index of 1.45 to 1.49.

It provides a heating film comprising a.

In addition, in another embodiment of the present application,

Forming a metal foil film on the first adhesive film;

patterning the metal foil film to form a metal foil pattern;

Forming a resin layer by coating and drying a composition for a resin layer on a release film;

Laminating the resin layer and the metal foil pattern

It provides a method for producing a heating film comprising a.

In addition, in another embodiment of the present application,

a first resin sheet; A resin layer having a refractive index of 1.45 to 1.49; And a heating film sequentially comprising a metal foil pattern,

A first glass provided on either side of the heating film, and

Including a second glass provided on the other side of the heating film,

The resin layer provides a heating glass for automobiles provided in contact with at least a portion of the surface of the metal foil pattern.

In addition, in another embodiment of the present application,

a second plastic substrate;

a first release layer provided on the second plastic substrate and having a release force of 5 gf/in to 70 gf/in; and

A resin layer provided on the first release layer, having a thickness of 3 μm to 50 μm, and a refractive index of 1.45 to 1.49

It provides a laminate for manufacturing automobile heating glass comprising a.

According to an exemplary embodiment of the present application, the deposition process can be omitted by using a metal foil film without forming a metal pattern through an expensive deposition process as in the prior art, and thus manufacturing a heating film at low cost by reducing the price of a fabric. can do.

In addition, according to an exemplary embodiment of the present application, since the heatable metal foil pattern is directly supported on the roll-shaped PVB film instead of the PET film, it is possible to manufacture laminated glass based on the metal foil pattern excluding the PET film. It may be advantageous for bonding with glass having a large curvature. In addition, it is possible to prevent a field of vision distortion caused by a difference in refractive index between the PET film and the PVB, which is a conventional problem.

In addition, since the heating glass for automobiles according to an exemplary embodiment of the present application uses a resin having the same refractive index as the interlayer of the laminated glass as an adhesion layer, the glass is laminated even if the roughness of the metal foil film is high. After the haze is reduced, optical properties can be improved.

1 to 4 are views schematically showing a heating film according to an exemplary embodiment of the present application, respectively.
5 to 7 are diagrams schematically showing a heating glass for automobiles according to an exemplary embodiment of the present application, respectively.

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

Among the methods adopted to impart a heating function with excellent optical performance to the windshield of a vehicle, in the case of a method of etching after forming a metal layer on PET, when the thickness of the metal becomes thick, a seed layer is deposited and then plated. However, the disadvantage is that the price is very high. Moreover, most automotive windshields are at least 1m in height and 1.4m in width, respectively. In addition, the height and width of many of them are 1.2m and 1.5m or more, respectively, and in the case of some large models, the height is also 1.4m or more. In order to secure the driver's field of vision, it is sufficient to heat only an area of 1m × 1.2m. However, due to the size of the windshield, it is necessary to prepare and pattern or etch a fabric having a metal layer with a larger area than necessary. In addition, a PET film applicable to a special purpose such as a windshield of an automobile is more expensive than a general film. Therefore, when PET, which is actually applicable to automobile windshields, is used from the metal patterning process, costs may increase and yields may decrease.

In addition, the metal layer in contact with the PET surface is a metal layer formed by sputtering and a seed layer of a thin film, which has a low surface roughness and shines smoothly, even if it is transparent when viewed from the PET surface after patterning. Because of its unique reflectivity, the pattern is easily recognized.

If patterning is performed after bonding the metal foil to PET with an adhesive, the unit cost of the fabric can be lowered. However, in this case, since the adhesive strength must be excellent to secure etching stability, when the adhesive is completely cured, a roughness corresponding to the surface roughness peculiar to the metal foil is generated on the adhesive surface, resulting in haze of the film and laminated glass. has the disadvantage of increasing In addition, since there is a difference in refractive index between PET and PVB, when laminated glass is made, the field of view may be distorted due to the difference in refractive index of each layer. On the other hand, since PVB is a thermoplastic resin and PET has very different deformation properties due to heat due to its crystallinity, bonding properties are not good when glass having a large curvature is used during bonding at high temperatures. In this way, other layers besides the essential elements of PET and metal are added, which complicates the structure and may affect the physical properties of the final laminated glass.

Auto glass companies usually prefer products in which a heating element is embedded on a PVB film rather than separately supplied with a heating film and PVB film. prefer In this case, it is preferable to produce the product in the form of a roll in which the heating element is supported on the PVB. In order to be able to produce a product in which a heating element is supported on a PVB film in a roll form, stable roll lamination must be possible for a short time of at least 5 minutes.

A method of forming a metal foil pattern on an adhesive film and then transferring it to a PVB sheet through a thermal bonding process was also attempted. However, in most of the known methods, the metal foil pattern on the adhesive film is transferred to the PVB sheet by pressing at high heat and pressure for a long period of time. For example, it was not easy to produce a product in the form of a roll with a metal foil pattern supported on PVB because it is performed under conditions such as bonding under vacuum for 15 minutes or more at a temperature of 100 ° C. or higher in a vacuum bonding machine. In addition, in such a long-term high-temperature and high-pressure condition, the inherent surface roughness of the PVB film for automobiles is damaged, making it difficult for air trapped inside to escape during the process of manufacturing the laminated glass, thereby degrading the characteristics of the laminated glass.

In addition, after forming a PVB coating layer on the copper foil, the PVB coating surface is attached and patterned on the first protective film to form a metal foil pattern layer, and then a second protective film is laminated on the metal foil pattern layer to form a layer on the PVB coating layer. It is proposed to produce a product in which a heating element is supported on a PVB sheet in a roll form using a product in which the formed metal foil pattern layer is protected by first and second protective films, respectively. However, in this case, it is difficult to precisely control the adhesion between the first and second protective films, and the fairness varies greatly depending on the adhesion of the first and second protective films to the PVB coating layer/metal foil pattern layer. there was In addition, when the surface of the copper foil is shiny, if the PVB is coated on the shiny surface, the adhesion to the substrate is not sufficient, so the wet process essential for subsequent patterning is not smooth, and the surface of the copper foil coated with PVB is matted through nodule treatment, etc. It had to have a character. In this case, when a metal foil pattern is formed through copper foil etching after resist patterning, residual copper film is likely to exist due to the lower nodule, so material and process margins are narrow to further etch the portion. If copper foil having a matte surface by nodule treatment and a shiny surface is used on one side and the other side is not nodular treated, and the patterning process is performed using dry film photoresist (DFR), the nodule treated surface PVB should be coated on and DFR should be laminated on the shiny side, but DFR usually has weaker adhesion properties on the shiny side than on the matte side, so there was difficulty in the process.

Therefore, in this application, it is intended to provide a heating film that has excellent heating characteristics at low voltage and is integrated with a bonding film used in a laminated glass process for automobiles. In addition, in the present application, it is possible to process a roll film without a PET film, and to provide a heating film in which a metal foil pattern is embedded in PVB and a heating glass for automobiles including the heating film.

A heating film according to an exemplary embodiment of the present application includes a first adhesive film; a metal foil pattern provided on the first adhesive film; and a resin layer provided in contact with at least a portion of a surface of the metal foil pattern that does not contact the first adhesive film and having a refractive index of 1.45 to 1.49.

In one embodiment of the present application, the first adhesive film includes a first plastic substrate and a first adhesive layer provided on the first plastic substrate, and the first adhesive layer is provided in contact with the metal foil pattern. can

The first plastic substrate is preferably a film having a visible light transmittance of 80% or more, such as polyethylene terephthalate (PET), cyclic olefin polymer (COP), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or acetyl celluloid. In particular, the first plastic substrate is more preferably PET. The thickness of the first plastic substrate may be 50 μm to 125 μm, but is not limited thereto.

The first adhesive layer may include at least one of a silicone-based polymer and an acrylic-based polymer.

The peel strength of the first adhesive film may be 10 gf/25 mm to 300 gf/25 mm, or 15 gf/25 mm to 100 gf/25 mm. In the present application, the peel strength of the first adhesive film may be measured by the ASTM D3330 evaluation method.

When the peel strength of the first adhesive film is less than 10 gf/25 mm, it may be difficult to stably support the metal foil when performing subsequent processes such as photolithography, development, and metal etching in a large-area roll-to-roll (R2R) process. In addition, when the peel strength of the first adhesive film exceeds 300 gf/25 mm, it may be difficult to appropriately remove the first adhesive film with low tension without damaging other layers of the film.

In one embodiment of the present application, the metal foil pattern is provided on the first adhesive film.

The height of the metal foil pattern may be 2 μm to 15 μm, and the metal foil pattern may include an aluminum foil pattern or a copper foil pattern. At this time, the height of the metal foil pattern can be measured with a micrometer or a thickness gauge.

The metal foil pattern may be manufactured from a metal foil including at least one surface of a mat surface having a relatively high ten-point average roughness (Rz). At this time, the mat surface of the metal foil may be in contact with the first adhesive film.

In the present application, the reflectance of the metal foil at a wavelength of 380 nm to 780 nm measured on a mat surface having a relatively high ten-point average roughness (Rz) may be 67% or less, 50% or less, or 30% or less. In addition, the metal foil pattern may include an aluminum foil pattern or a copper foil pattern having an average reflectance of 15% or less at a wavelength of 380 nm to 780 nm.

The reflectance may be measured with equipment such as UV-3600 or Solidspec-3700 manufactured by Shimadzu, Japan.

The line width of the metal foil pattern may be 4 μm to 20 μm, and sheet resistance may be 0.05 ohm/sq to 0.5 ohm/sq. In addition, based on the entire upper area of the first adhesive film, the ratio of the upper area of the first adhesive film provided with the metal foil pattern may be 20% or less, 10% or less, or 1% to 20%. , 1% to 10%. In addition, the total length of lines of the metal foil pattern included in the area of 25 cm ² may be 2 m to 11 m.

In an exemplary embodiment of the present application, the resin layer is provided in contact with at least a part of a surface that does not contact the first adhesive film of the metal foil pattern, and has a refractive index of 1.45 to 1.49. As for the refractive index of the said resin layer, it is more preferable that it is 1.47-1.48.

In this application, the refractive index of the resin layer is measured by a Prism Coupler (Example of Equipment - 2010/M by Metricon), an ellipsometer (Example of Equipment - UVISEL by Horriba Scientific), an Abbe Refractometer (Equipment) Example - Can be measured with Kruss' AR4), etc. For example, the refractive index may be calculated by measuring a change in the amount of light reflected from the coating layer using a prism coupler. More specifically, a material whose refractive index is to be measured is coated on a glass or other substrate whose refractive index is known to a thickness of several μm by a method such as spin coating, and then the coated sample is brought into contact with a prism. Afterwards, when the laser is incident on the prism, it is mostly totally reflected, but when a specific incident angle and condition are satisfied, an evanescent field is generated at the interface and the light is coupled. When coupling occurs and the angle at which the intensity of light detected by the detector rapidly decreases is measured, the prism coupler can automatically calculate the refractive index of the coating layer from parameters related to the polarization mode of light and the refractive index of the prism and the substrate.

In general, automobile windshields are manufactured by inserting a bonding film between two sheets of glass panes and bonding them together at high temperature and high pressure. At this time, polyvinyl butyral (PVB) and ethyl vinyl acetate (EVA) are mainly used as bonding films, and the refractive index of these materials is 1.45 to 1.49, and most of them are 1.47 to 1.48. Since the haze can be reduced if the refractive indices of the resin layer/junction film are the same or the difference is small after glass lamination, it is preferable to adjust the refractive index of the resin layer to 1.45 to 1.49. If the refractive index of the resin layer has a large difference from that of the bonding film, light transmits through the glass and has a high haze due to internal scattering, which is more severe when the irregularities of the resin layer are large.

In addition, the resin layer may include at least one of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and acrylate-based polymers. In particular, the resin layer preferably contains polyvinyl butyral (PVB).

A glass transition temperature (Tg) of the resin layer may be 25 °C to 80 °C or 25 °C to 60 °C. When the glass transition temperature of the resin layer is less than 25° C., it is difficult to stably store the manufactured heating film at room temperature. In addition, when the heating film is laminated with the bonding film and glass and bonded at high temperature/high pressure, if the glass transition temperature of the resin layer is low, the fluidity increases, and the metal foil pattern is deformed, making it more vulnerable to tension or disconnection. When the glass transition temperature of the resin layer exceeds 80 ° C., it is difficult to perform lamination with a lower substrate and heat, which will be described later.

The resin layer may be provided on at least a part of the surface of the metal foil pattern that does not contact the first adhesive film, and may be provided on the entire surface of the metal foil pattern that does not contact the first adhesive film. In addition, at least a portion of the resin layer may be provided in contact with the first adhesive film. In addition, the metal foil pattern may be provided by being embedded in the resin layer. As described above, in one embodiment of the present application, the resin layer may be provided only on the surface of the metal foil pattern that does not contact the first adhesive film and surround the surface of the metal foil pattern, and the resin layer Silver may be provided on the entirety of the first adhesive film and the metal foil pattern.

The thickness of the resin layer on the metal foil pattern or the thickness of the resin layer on the first adhesive film may be independently 3 μm to 50 μm. More specifically, the resin layer may have a thickness of 3 μm to 50 μm, 3 μm to 30 μm, or 10 μm to 25 μm. When the thickness of the resin layer exceeds 50 μm, the resin layer material is unnecessarily wasted, and it is difficult to stably manufacture the resin layer due to difficult solvent drying. In addition, when the bonding film and glass are laminated on both sides of the heating film after manufacturing the heating film and bonded at high temperature/high pressure, the metal foil pattern may be deformed to cause tension or disconnection.

In one embodiment of the present application, the resin layer may be provided in conformal contact with at least a part of the surface of the metal foil pattern that does not contact the first adhesive film. In the present application, the conformal contact means that the resin layer contacts at least a part of the surface of the metal foil pattern that does not contact the first adhesive film without voids. That is, according to an exemplary embodiment of the present application, the resin layer may completely cover surface irregularities caused by surface roughness of the metal foil pattern without voids.

In one embodiment of the present application, a release film may be further included on the metal foil pattern and the resin layer.

The release film may include a second plastic substrate and a first release layer provided on the second plastic substrate, and the first release layer may be provided in contact with the resin layer.

The second plastic substrate is preferably a film having a visible light transmittance of 80% or more, such as polyethylene terephthalate (PET), cyclic olefin polymer (COP), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or acetyl celluloid. In particular, it is more preferable that the second plastic substrate is PET.

The first release layer may include a silicone-based, melamine-based, or norbornene-based polymer, or a mixture thereof.

The release force of the release film is not significantly limited as long as it is easy to coat the composition for the resin layer on the release film, and then the resin layer coated on the release film can be transferred onto the metal foil pattern by a thermal lamination process. More specifically, the release force of the release film evaluated by the peel force measured based on the TESA7475 tape may be 5 gf/in to 70 gf/in.

In addition, for smooth running or release, the second plastic substrate or the first release layer may include fine protrusions.

The heating film according to an exemplary embodiment of the present application may further include a first resin sheet on the metal foil pattern and the resin layer. In addition, the heating film according to an exemplary embodiment of the present application further includes a first resin sheet on the metal foil pattern and the resin layer, and the metal foil pattern and the resin layer are embedded in the first resin sheet. It can be.

The heating film including the first resin sheet may be manufactured by removing the release film from the above-described heating film including the release film and laminating the first resin sheet on the metal foil pattern and the resin layer.

The first resin sheet itself does not have adhesion properties with an adherend, but may be a substrate capable of imparting adhesion to an adherend after thermal lamination at a temperature of 40° C. to 120° C. More specifically, the first resin sheet may include a thermoplastic resin, and the thermoplastic resin may include at least one of polyvinyl butyral (PVB) and ethyl vinyl acetate (EVA). In addition, the thickness of the first resin sheet may be 100 μm to 800 μm, 100 μm to 400 μm, 400 μm to 800 μm, or 300 μm to 500 μm.

In an exemplary embodiment of the present application, a difference in refractive index between the resin layer and the first resin sheet may be 0.03 or less and may be 0 or more.

In one embodiment of the present application, the resin layer means a layer formed by coating a composition for forming a resin layer, and the resin sheet means using a film form. In addition, as described above, the thickness of the resin layer is 3 μm to 50 μm, the thickness of the resin sheet is 100 μm to 800 μm, etc., and the resin layer and the resin sheet can be distinguished from each other.

In one embodiment of the present application, a blackening layer may be further included in at least a portion of the metal foil pattern. In addition, a blackening layer pattern may be further included in at least a portion between the metal foil pattern and the resin layer. At least a portion between the metal foil pattern and the resin layer may be a surface not in contact with the first adhesive film of the metal foil pattern, and more specifically, may be an upper surface and a side surface of the metal foil pattern. The blackening layer pattern may include one or more materials such as chromium-based, selenium-based, copper sulfide-based, copper oxide-based, copper nitride-based, copper sulfide-based, aluminum oxynitride-based, and copper oxynitride-based materials. The blackening layer pattern is formed by wet coating the above-mentioned material on at least a part of the surface of the metal foil pattern that does not come into contact with the first adhesive film, or a material such as aluminum oxynitride or copper oxynitride is applied at 30 nm to 30 nm. It can be formed by a sputtering process at 70 nm.

A heating film according to an exemplary embodiment of the present application is schematically shown in FIGS. 1 to 4 below.

1, the heating film according to an exemplary embodiment of the present application has a structure in which a first adhesive film 10, a metal foil pattern 20, a resin layer 30, and a release film 40 are sequentially stacked. can

In addition, as shown in FIG. 2 below, in the heating film according to an exemplary embodiment of the present application, the first adhesive film 10, the metal foil pattern 20, the resin layer 30, and the first resin sheet 50 are sequentially laminated. may have a structure.

In addition, as shown in FIG. 3 below, the heating film according to an exemplary embodiment of the present application may have a structure in which a metal foil pattern 20, a resin layer 30, and a first resin sheet 50 are sequentially stacked.

In addition, as shown in FIG. 4 below, the heating film according to an exemplary embodiment of the present application has a structure in which a metal foil pattern 20, a resin layer 30, and a first resin sheet 50 are sequentially stacked, and the metal foil pattern (20) may be provided by being buried in the inside of the resin layer (30).

In addition, a method for manufacturing a heating film according to an exemplary embodiment of the present application includes forming a metal foil film on a first adhesive film; patterning the metal foil film to form a metal foil pattern; Forming a resin layer by coating and drying a composition for a resin layer on a release film; and laminating the resin layer and the metal foil pattern.

In an exemplary embodiment of the present application, contents of the metal foil film, the resin layer, the first adhesive film, and the release film are the same as described above.

In one embodiment of the present application, the first adhesive film includes a first transparent substrate and a first adhesive layer provided on the first transparent substrate, and the first adhesive layer is provided to contact the metal foil film. can make it

In one embodiment of the present application, when the thickness of the metal foil film is 5 μm or less, a carrier layer may be introduced to the rear surface of the metal foil film for ease of handling. The carrier layer may be copper foil or aluminum foil.

In one embodiment of the present application, the forming of the metal foil pattern by patterning the metal foil film may use a conventional resist patterning process known in the art. That is, after forming a resist pattern on the metal foil film, the metal foil pattern may be formed through an etching process.

A method for manufacturing a heating film according to an exemplary embodiment of the present application includes forming a resin layer by coating and drying a composition for a resin layer on a release film. The step of coating the composition for the resin layer on the release film may use comma coating, gravure coating, slot die coating, or the like.

A method of manufacturing a heating film according to an exemplary embodiment of the present application includes laminating the resin layer and the metal foil pattern. More specifically, the lamination may be performed by a roll-to-roll thermal lamination process on the coated and dried resin layer surface and the metal foil pattern surface at a temperature of 40 ° C to 120 ° C, and the second release on the resin layer. A roll-to-roll thermal lamination process may be performed on the resin layer surface and the metal foil pattern surface at a temperature of 40° C. to 120° C. while additionally forming a film and removing the second release film. At this time, the second release film is for protecting the resin layer, and the release force of the release film directly coated with the composition for the resin layer is preferably greater than the release force of the second release film.

The composition for the resin layer may include the above-described material for the resin layer and a solvent capable of dissolving them. The solvent is not particularly limited as long as it can dissolve the material for the resin layer, and examples thereof include methanol, ethanol, isopropanol, methyl ethyl ketone, NMP, cellosolve-based materials, and mixtures thereof.

The method for manufacturing a heating film according to an exemplary embodiment of the present application includes, after laminating the resin layer and the metal foil pattern, removing the release film; laminating a first resin sheet on the resin layer; and removing the first adhesive film.

The step of laminating the first resin sheet on the resin layer may be performed by a roll-to-roll thermal lamination process at a temperature of 40° C. to 120° C. After the roll-to-roll thermal lamination process, the first resin sheet is in contact with the surface portion and the side portion of the metal foil pattern and the resin layer, and the surface irregularities due to the surface roughness of the metal foil pattern and the resin layer are formed through pores as much as possible. It is preferable to make conformal contact that covers the entire surface without voids. In addition, the first resin sheet may be provided in contact with the first adhesive film.

The removing of the first adhesive film may be performed by a process of removing the first adhesive film after UV or heat irradiation.

In addition, the heating glass for automobiles according to an exemplary embodiment of the present application includes a first resin sheet; A resin layer having a refractive index of 1.45 to 1.49; and a heating film sequentially including a metal foil pattern, a first glass provided on one side of the heating film, and a second glass provided on the other side of the heating film, wherein the resin layer comprises the metal foil pattern. It is provided in contact with at least a part of the surface of.

In one embodiment of the present application, the first glass and the second glass are not particularly limited, and glass known in the art may be applied.

In one embodiment of the present application, the metal foil pattern and the resin layer may be provided by being embedded in the first resin sheet.

In one embodiment of the present application, a second resin sheet may be further included on at least one of a surface between the heating film and the first glass and a surface between the heating film and the second glass.

The second resin sheet itself does not have adhesion properties to an adherend, but may be a substrate capable of imparting adhesion to an adherend after thermal lamination at a temperature of 40° C. to 120° C. More specifically, the first resin sheet may include a thermoplastic resin, and the thermoplastic resin may include at least one of polyvinyl butyral (PVB) and ethyl vinyl acetate (EVA). In addition, the second resin sheet may have a thickness of 100 μm to 800 μm, 100 μm to 400 μm, 400 μm to 800 μm, or 300 μm to 500 μm. In addition, the first resin sheet and the second resin sheet may include the same material or different materials.

In one embodiment of the present application, the haze of the heating glass for automobiles may be 0.3% to 2%.

According to an exemplary embodiment of the present application, a pair of opposing bus bars for applying electricity to the metal foil pattern may be further included.

According to one embodiment of the present application, a black pattern may be provided to conceal the bus bar. For example, the black pattern may be printed using a paste containing cobalt oxide. At this time, screen printing is suitable for the printing method, and the thickness may be set to 10 μm to 100 μm. The metal pattern and the bus bar may be formed before or after forming the black pattern, respectively.

The heating glass for automobiles according to an exemplary embodiment of the present application may be connected to a power source for heat generation, and in this case, the heating amount per m ² is 100W to 1,000W, preferably 200W to 700W. In the heating glass for automobiles according to an exemplary embodiment of the present application, the heating element has excellent heating performance even at a low voltage, for example, 30V or less, preferably 20V or less.

A heating glass for automobiles according to an exemplary embodiment of the present application is schematically shown in FIGS. 5 to 7 below.

5, heating glass for automobiles according to an exemplary embodiment of the present application includes a first glass 70, a second resin sheet 60, a metal foil pattern 20, a resin layer 30, and a first resin sheet. 50 and the second glass 80 may have a sequentially stacked structure. At this time, a pair of bus bars 90 may be further included on the metal foil pattern 20 . In addition, the thickness of the first resin sheet 50 and the second resin sheet 60 may be each independently 100 μm to 400 μm.

In addition, as shown in FIG. 6, the heating glass for automobiles according to an exemplary embodiment of the present application includes a first glass 70, a second resin sheet 60, a first resin sheet 50, a resin layer 30, The metal foil pattern 20 and the second glass 80 may have a structure in which they are sequentially stacked. At this time, a pair of bus bars 90 may be further included on the metal foil pattern 20 . In addition, the thickness of the first resin sheet 50 and the second resin sheet 60 may be each independently 100 μm to 400 μm.

In addition, as shown in FIG. 7 below, the heating glass for automobiles according to an exemplary embodiment of the present application includes a first glass 70, a first resin sheet 50, a resin layer 30, a metal foil pattern 20, and a second The glass 80 may have a sequentially stacked structure. At this time, a pair of bus bars 90 may be further included on the metal foil pattern. In addition, the thickness of the first resin sheet 50 may be 400 μm to 800 μm.

5 to 7, since the glass is left at high temperature and pressure for a long time during bonding, the space spaced apart from the glass by the thickness of the metal foil pattern and the bus bar may be filled by the resin layer and the first resin sheet. Since both the ground layer and the first resin sheet may have the same refractive index, it may be difficult to visually distinguish the two after glass bonding. In addition, since the resin layer, the first resin sheet, and the second resin sheet may all have the same refractive index, it may be difficult to distinguish the three after glass bonding.

In addition, the laminate for manufacturing automobile heating glass according to an exemplary embodiment of the present application includes a second plastic substrate; a first release layer provided on the second plastic substrate and having a release force of 5 gf/in to 70 gf/in; and a resin layer provided on the first release layer, having a thickness of 3 μm to 50 μm, and a refractive index of 1.45 to 1.49.

According to an exemplary embodiment of the present application, the deposition process can be omitted by using a metal foil film without forming a metal pattern through an expensive deposition process as in the prior art, and thus manufacturing a heating film at low cost by reducing the price of a fabric. can do.

In addition, according to an exemplary embodiment of the present application, since the heatable metal foil pattern is directly supported on the roll-shaped PVB film instead of the PET film, it is possible to manufacture laminated glass based on the metal foil pattern excluding the PET film. It may be advantageous for bonding with glass having a large curvature. In addition, it is possible to prevent a field of vision distortion caused by a difference in refractive index between the PET film and the PVB, which is a conventional problem.

In addition, since the heating glass for automobiles according to an exemplary embodiment of the present application uses a resin having the same refractive index as the interlayer of the laminated glass as an adhesion layer, the glass is laminated even if the roughness of the metal foil film is high. After the haze is reduced, optical properties can be improved.

Hereinafter, exemplary embodiments described in this specification are illustrated through examples. However, it is not intended that the scope of the embodiments be limited by the following examples.

< Example >

< Example 1>

A coating solution having a composition of 12 parts by weight of a PVB sheet having a refractive index of 1.47 and a glass transition temperature (Tg) of 32° C., 44 parts by weight of ethanol, and 44 parts by weight of methyl ethyl ketone was applied to a release film having a thickness of 50 μm and a release force of 60 gf/in. After coating on the release layer, it was dried at 120° C. for 5 minutes to form a PVB coating layer having a thickness of 23 μm.

Separately, a substrate was prepared by laminating a first adhesive film having a PET/adhesive layer structure having a peel strength of 60 gf/25 mm as measured by the ASTM D3330 evaluation method on a matt surface of copper foil having a thickness of 12 μm. At this time, the surface roughness (Rz) of the matt surface of the 8 μm copper foil was 1.63 to 2.54 μm, and the first adhesive film was coated with a 7 μm thick silicon-based first adhesive layer on 75 μm thick PET. Thereafter, the surface of the copper foil was washed/washed/dried with 0.5 wt% sulfuric acid, and then a dry film resist (DFR) having a thickness of 15 μm was laminated on the surface of the copper foil at 110° C. Thereafter, a first adhesive film / metal foil pattern layer film was prepared through photolithography → development → etching → peeling → blackening process. At this time, a 0.2 wt% aqueous solution of potassium carbonate was used as the developing solution, an aqueous solution based on 20 wt% iron chloride as the etching solution, a 2% aqueous solution of sodium hydroxide as the stripping solution, and a selenium compound dissolved in an acidic aqueous solution based on phosphoric acid as the blackening solution. liquid was used. At this time, the line width of the copper foil pattern was 15 to 23 μm.

Thereafter, the first adhesive layer surface of the release film / PVB coating layer film and the metal foil pattern surface of the first adhesive film / metal foil pattern layer film are laminated at a speed of 0.7 m / min at a temperature of 80 ° C. Film / metal foil pattern layer / PVB coating layer / release film products were produced. Then, the release film was removed from the PVB coating layer through a delamination process. Thereafter, the first adhesive film / metal foil pattern layer / PVB coating layer surface from which the release film was removed and the first PVB film having a thickness of 380 μm were attached to the surface of the first adhesive film / metal foil pattern layer / PVB coating layer film by roll lamination on a rubber roll set to a temperature of 80 ° C., A structure of the first adhesive film / metal foil pattern layer / PVB coating layer / first PVB film was prepared.

Then, after removing the first adhesive film from the structure, the first PVB film side of (1) from which the first adhesive film was removed is laminated on the top of the first glass so that it comes into contact with the surface of the second glass, and the first adhesive film After the film is removed, the first and second bus bars made of copper foil with a width of 1 cm and a thickness of 50 μm are installed on both ends of the upper part where the pattern side of the metal foil pattern film is exposed, and then 380 μm thick to cover the pattern side and the bus bar. The second PVB film of was laminated thereon, and after laminating the first glass thereon, vacuum lamination was performed at 120 ° C. for 20 minutes to prepare a heat-generating laminated glass in which a copper pattern was embedded between PVB. The sheet resistance of the exothermic laminated glass thus prepared was 0.22 ohm/sq.

< comparative example 1>

A first adhesive film having a peel strength of 173 gf/25 mm was laminated on a matt surface having a surface roughness (Rz) value of 1.5 μm in a 3 μm copper foil. At this time, the 3㎛ copper foil used a product released with the shiny surface supported by an 18㎛ thick carrier copper foil, and the carrier copper foil was removed before forming a pattern on the shiny surface. Thereafter, a copper foil pattern layer was formed on the first adhesive film through pretreatment of the copper foil surface → formation of a resist pattern → etching → peeling process. After that, without forming a release film / PVB coating layer and transferring the first PVB sheet directly to the first adhesive film / metal foil pattern layer film at a temperature of 80 ° C to 120 ° C, roll-to-roll (R2R) thermal lamination was attempted, but the metal foil Despite the low thickness of 3 μm, the adhesion between the first PVB sheet and the metal foil pattern layer was not good, so it was not possible to roll-to-roll (R2R) thermal lamination of the first PVB sheet or to remove the first adhesive film. This was the same even when the peel strength of the first adhesive film was lowered to 30 gf/in.

According to an exemplary embodiment of the present application, the deposition process can be omitted by using a metal foil film without forming a metal pattern through an expensive deposition process as in the prior art, and thus manufacturing a heating film at low cost by reducing the price of a fabric. can do.

In addition, according to an exemplary embodiment of the present application, since the heatable metal foil pattern is directly supported on the roll-shaped PVB film instead of the PET film, it is possible to manufacture laminated glass based on the metal foil pattern excluding the PET film. It may be advantageous for bonding with glass having a large curvature. In addition, it is possible to prevent a field of vision distortion caused by a difference in refractive index between the PET film and the PVB, which is a conventional problem.

In addition, since the heating glass for automobiles according to an exemplary embodiment of the present application uses a resin having the same refractive index as the interlayer of the laminated glass as an adhesion layer, the glass is laminated even if the roughness of the metal foil film is high. After the haze is reduced, optical properties can be improved.

10: first adhesive film
20: metal foil pattern
30: resin layer
40: release film
50: first resin sheet
60: second resin sheet
70: first glass
80: second glass
90: bus bar

Claims (3)

Forming a metal foil film on the first adhesive film;
patterning the metal foil film to form a metal foil pattern;
Forming a resin layer by coating and drying a composition for a resin layer on a release film; and
Laminating the resin layer and the metal foil pattern
As a method for producing a heating film comprising a,
After laminating the resin layer and the metal foil pattern,
removing the release film;
laminating a first resin sheet on the resin layer; and
Further comprising the step of removing the first adhesive film,
The difference in refractive index between the resin layer and the first resin sheet is 0 or more and 0.03 or less. The method of claim 1, wherein the step of laminating the resin layer and the metal foil pattern is performed by a roll-to-roll thermal lamination process at a temperature of 40° C. to 120° C. The method of claim 1, wherein the laminating of the first resin sheet on the resin layer is performed by a roll-to-roll thermal lamination process at a temperature of 40° C. to 120° C.

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