Window film and method for manufacturing window film
The window film integrates UV-blocking PET film and IR-blocking layers with a heat-shielding hard coat to balance high visible light transmittance with effective UV and IR blocking, addressing durability and regulatory compliance issues.
Patent Information
- Application Number
- JP2024052175
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-10-09
AI Technical Summary
Existing window films that block ultraviolet and infrared rays also significantly reduce visible light transmittance, violating legal regulations and causing issues with visibility and eye fatigue, while conventional UV-blocking agents in adhesives lead to durability and effectiveness loss over time.
A window film structure comprising a UV-blocking PET film with integrated UV-blocking agents, an IR-blocking adhesive layer with diimonium dye, a transparent PET film, a heat-shielding hard coat layer with tin-doped indium oxide, and a transparent adhesive layer, with each layer optimized for minimal visible light blocking and high durability.
The film achieves high visible light transmittance, effectively blocking UV and IR rays, meeting legal requirements and ensuring durability by integrating UV-blocking agents into the PET film, thereby maintaining excellent visibility and heat shielding.
Smart Images
Figure 2025150982000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a window film and a method for manufacturing the window film, and more particularly to a window film that has a high visible light transmittance and therefore excellent visibility, and also has a high infrared and ultraviolet blocking rate, and a method for manufacturing the window film. [Background technology]
[0002] Sunlight can be broadly divided into ultraviolet rays (below 380nm), visible light (380-780nm), and infrared rays (above 780nm), and window films that have the function of adjusting the transmittance or reflectance of wavelengths between 300 and 2500nm are called window films.
[0003] Traditionally, so-called windows in buildings, vehicles, and exhibitions have been made from transparent glass sheets to transmit sunlight, which includes visible light, ultraviolet light, and infrared light.
[0004] It has been pointed out that prolonged exposure of skin to ultraviolet rays contained in sunlight can cause sunburns and have adverse effects on the human body, including skin aging and the development of cancer. In addition, deterioration of packaging materials due to ultraviolet rays often leads to deterioration of the contents and discoloration of interior decor.
[0005] Infrared rays cause problems such as increasing indoor temperatures due to direct sunlight, reducing the effectiveness of air conditioning in the summer, which leads to higher air conditioning costs in the summer.In addition, the glare of visible light limits the field of vision and increases eye fatigue.
[0006] In recent years, in order to block direct irradiation of sunlight, including ultraviolet rays, infrared rays, and visible light, into a room, products such as window films that are attached to glass windows of automobiles, buildings, etc. to prevent exposure to ultraviolet rays, infrared rays, and visible light have been developed and have reached a practical level.
[0007] Such window films not only block ultraviolet, infrared, and visible light by themselves, but also perform a variety of other functions, such as supplementing the mechanical strength of window glass, preventing glass fragments from scattering if the window glass is broken, and, when a colored film is applied, protecting personal privacy by preventing outsiders from looking into the interior of the room.
[0008] However, because the heat-shielding material in such window films blocks visible light, there is a problem in that it is difficult to expand the product in cases where there are regulations on the transmittance of visible light, such as in automobile glass.
[0009] Therefore, this invention is a technology related to a product that can suppress and block ultraviolet and infrared rays and has a high heat-blocking rate, while minimizing the blocking rate of visible light. Summary of the Invention [Problem to be solved by the invention]
[0010] The present invention has been made to solve the above problems, and an object of the present invention is to provide a window film that maximizes the transmittance of visible light, suppresses and blocks ultraviolet and infrared rays, and has a high heat-shielding rate.Another object of the present invention is to provide a window film that can prevent damage caused by exposure to ultraviolet rays by forming a UV-blocking layer to ensure the durability of the PET film and various coating layers. [Means for solving the problem]
[0011] The window film of the present invention is characterized by comprising: an ultraviolet (UV) blocking film 130 in which PET chips and resin chips containing an ultraviolet blocking agent are regularly arranged on a polyethylene terephthalate (PET) film for blocking ultraviolet light; an infrared (IR) blocking adhesive layer 140 coated on the upper surface of the UV blocking film 130 to block part of the visible light range and infrared light and containing a diimonium dye for blocking near-infrared light; a transparent PET film 150 disposed on the upper surface of the IR blocking adhesive layer 140; a heat-shielding hard coat layer 160 coated on the upper surface of the transparent PET 150 with a dispersed tin-doped indium oxide (ITO) additive; a transparent adhesive layer 120 coated on the lower surface of the UV blocking film 130 to block ultraviolet light and adhere to a glass window; and a release film 110 disposed on the lower surface of the transparent adhesive layer 120 to protect the transparent adhesive layer and to be peeled off during product installation.
[0012] The UV blocking film may be characterized in that an ultraviolet blocking agent is added to PET chips, which are melted and then processed into a film.
[0013] Furthermore, the thickness of each layer constituting the window film 100 may be characterized in that the heat-shielding hard coat layer 160 is 2 to 4 μm, the transparent PET film 150 is 21 μm to 25 μm, the IR-blocking adhesive layer 140 is 4 to 6 μm, the UV-blocking film 130 is 23 to 27 μm, the transparent adhesive layer 120 is 8 to 10 μm, and the release film 110 is 21 μm to 25 μm.
[0014] Furthermore, the window film may be rolled up and stored, and may further comprise a release film arranged to be positioned on the underside of the adhesive layer to protect the adhesive layer during storage, and the release film may be peeled off when the window film is attached to a glass window.
[0015] The method for manufacturing a window film of the present invention is characterized by comprising the steps of: forming an IR-blocking adhesive layer 140 on an upper surface of a UV-blocking film 130, and adhering a transparent PET film 150, which functions as a base film, to the upper surface of the IR-blocking adhesive layer 140 to manufacture a first semi-finished product 10; and forming a heat-shielding hard coat layer 160 on an upper surface of the transparent PET film 150 of the first semi-finished product, forming a transparent adhesive layer 120 on a lower surface of the UV-blocking film 130 of the first semi-finished product 10, and forming a release film 110 on the lower surface of the transparent adhesive layer 120 to manufacture a second semi-finished product.
[0016] In addition, the primary semi-finished product 10 is manufactured by carrying out the following steps: a UV blocking film supply step (S100) in which a UV blocking film 130 that blocks ultraviolet rays is supplied; a IR blocking adhesive layer 140 formation step (S110) in which an adhesive layer is formed on the upper surface of the UV blocking film 130; a drying and curing step (S120) in which the IR blocking adhesive layer 140 is dried and cured; a transparent PET film supply step (S130) in which a transparent PET film is supplied on the upper surface of the IR blocking adhesive layer; a lamination step (S140) in which the lower surface of the transparent PET film 150 is bonded to the IR blocking adhesive layer; and a step (S150) in which the processed film is wound up around a 6-inch cardboard tube.
[0017] Furthermore, the second semi-finished product 20 includes a first semi-finished product supply step (S200) in which the first semi-finished product 10 is supplied, a heat-shielding hard-coat layer forming step (S210) in which the heat-shielding hard-coat layer 160 is formed on the upper surface of the transparent PET film 150, a first drying and curing step (S220) in which the heat-shielding hard-coat layer 160 is dried by hot air and cured by UV, and a transparent adhesive layer forming step (S230) in which the transparent adhesive layer 120 is formed on the lower surface of the UV blocking film 130 after the first drying and curing step (S220), and After the transparent adhesive layer forming step (S230), the transparent adhesive layer 120 is dried and cured in a second drying and curing step (S240), a release film supplying step (S250) in which a release film 110 is supplied to be positioned on the underside of the transparent adhesive layer 120 to protect the transparent adhesive layer 120, a laminating step (S260) in which the release film 110 is laminated to the transparent adhesive layer 120, and a step (S250) in which the processed film is wound up on a 6-inch cardboard tube are carried out to manufacture the film. [Effects of the Invention]
[0018] The window film and method for manufacturing a window film according to the present invention, configured as described above, can provide a highly durable window film by adding a UV-blocking additive to a PET film to form a UV-blocking layer, and can also provide a window film that minimizes the visible light blocking rate, thereby achieving a low visible light blocking rate subject to legal regulations, while suppressing and blocking ultraviolet and infrared rays and providing a high heat-blocking rate. [Brief explanation of the drawings]
[0019] [Figure 1] 1 is a cross-sectional view of a window film structure according to an embodiment of the present invention. [Figure 2] 1 is a flowchart showing a method for manufacturing a primary semi-finished product of a window film according to an embodiment of the present invention. [Figure 3] 3A to 3C are flow charts showing a method for manufacturing a secondary semi-finished product of a window film according to an embodiment of the present invention. [Figure 4] 1A and 1B are cross-sectional views of a first semi-finished product and a second semi-finished product of a window film according to an embodiment of the present invention. [Figure 5] Explanatory diagram for measuring spectral transmittance [Figure 6] Data chart on spectral transmittance of window film (Part 1) [Figure 7] Spectral transmittance and spectral reflectance measurement results table [Figure 8] Data chart on spectral transmittance of window film (Part 2) DETAILED DESCRIPTION OF THE INVENTION
[0020] Hereinafter, the above-described embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0021] 1 is a cross-sectional view of the structure of a window film according to an embodiment of the present invention. As shown in FIG. 1, from the bottom, a release film 110, a transparent adhesive layer 120, a UV blocking film 130, an IR blocking adhesive layer 140, a transparent PET film 150, and a heat-shielding hard coat layer 160 are arranged in this order.
[0022] The window films 100 arranged in the above-mentioned order are wound up in a roll and stored, and then cut into the required length for installation and attached to the glass window. At this time, the transparent adhesive layer 120 is in contact with the glass window, and the window film 100 is attached to the glass window so that the heat-shielding hard coat layer 160 is located on the outermost side.
[0023] The IR-blocking adhesive layer 140 is intended to block part of the visible light range and infrared light, and is formed by adding a diimmonium dye to block near-infrared light. In this example, the raw materials used for the IR-blocking adhesive layer 140 are listed in Table 1. Table 1 lists the names, blending ratios, uses, and product manufacturers of the raw materials used to form the IR-blocking adhesive layer. A specific method for creating the IR-blocking adhesive layer is described below. First, 2. N-110 and 3. CS2162 listed in Table 1 are weighed and placed in a blending container, followed by weighing and stirring 4. MEK (dilution solvent). Next, 1. S-10 (51.22%) is weighed and added and stirred to complete the mixture. Note that if the blending ratios deviate from those listed in Table 1 by more than a certain amount, the ingredients will not mix. (Table 1) TIFF2025150982000002.tif64166
[0024] The heat-shielding hard coat layer 160 is a hard coat layer containing ITO, and the ITO functions to block infrared wavelengths in the long wavelength range.
[0025] In this example, the raw materials for the heat-shielding hard coat layer 160 shown in Table 2 were used. Table 2 lists the names, blending ratios, uses, and product manufacturers of the raw materials used to form the heat-shielding hard coat layer. Next, we will explain the specific method for creating the heat-shielding hard coat layer. First, 2. KTO-46, 3. BY-1819, and 4. 2200N listed in Table 2 are weighed and placed in a blending container, and then 6. MEK (dilution solvent) is weighed and added and stirred. Next, 5. ITO (heat-shielding agent) is weighed and added and stirred. Finally, 1. TUVR-HC is weighed and added and stirred to complete the mixture. Note that if the blending ratios shown in Table 2 deviate by more than a certain amount, the ITO and other ingredients will not be mixed. (Table 2) TIFF2025150982000003.tif83166
[0026] In addition, when using existing heat-shielding materials such as ATO (antimony-doped tin oxide) or CTO (cesium-doped tungsten oxide), there is a problem that the visible light blocking rate becomes high.
[0027] The transparent PET film 150 is located below the heat-shielding hard coat layer 160 and is characterized by being made of a transparent film.
[0028] The UV blocking film 130 is a functional film that blocks ultraviolet rays up to 400 nm. Conventionally, UV blocking agents have been added to adhesives or pressure-sensitive adhesives, but this has the problem of discoloration occurring within a few months of application of the window film 100 due to low durability, and also of a decrease in the UV blocking rate.
[0029] However, the UV blocking film 130 of the present invention is characterized by being made by adding a UV blocking agent to a PET film. During the PET film manufacturing process, PET chips and resin chips containing a UV blocking agent are mixed together to manufacture the PET film, which blocks UV rays contained in sunlight and has the advantage of being highly durable.
[0030] At this time, the resin chips containing UV blocking agent must be smoothly melted at high temperatures and mixed well with the PET chips. To achieve this, it is preferable that the PET chips and the resin chips containing UV blocking agent are formed to have substantially the same shape and specific gravity, so that the PET chips and the resin chips containing UV blocking agent are mixed evenly and arranged regularly on the PET film without being solidified in a specific area.
[0031] Therefore, the film method, which imparts UV blocking properties to the film, is more durable than the method of adding a UV blocking agent to a conventional adhesive or glue.
[0032] The transparent adhesive layer 120 is a layer that brings the substrate into contact with the surface of a glass window, and is coated with a sticky adhesive to adhere to a substrate such as glass. The transparent adhesive layer 120 maintains its sticky state over time, so it may be applied to a glass window after the film is produced.
[0033] However, if the transparent adhesive layer 120 is stored in an open state, there is a risk that dust or foreign matter may adhere to the transparent adhesive layer 120, so in order to prevent the transparent adhesive layer 120 from becoming dirty, a release film 110 is attached to the underside of the transparent adhesive layer 120 before storage.
[0034] The release film 110 is attached to the underside of the transparent adhesive layer 120 to protect the transparent adhesive layer 120, and is preferably stored with the release film 110 attached when the window film 100 is stored, and when the film is applied to a glass window, the release film 110 is peeled off and the transparent adhesive layer 120 comes into contact with the glass window. Since the release film 110 is normally in contact with the transparent adhesive layer 120, if the release film 110 contains a substance that reacts with the transparent adhesive layer 120, it may react with the reactive groups contained in the transparent adhesive layer 120 and reduce its adhesive performance. Therefore, the release film 110 is required to be free of substances that react with the transparent adhesive layer 120, and must be formed to be heat resistant to prevent the release film 110 from warping depending on the season.
[0035] In this case, it is preferable that the thickness of each layer constituting the window film 100 is 2 to 4 μm for the heat-shielding hard coat layer 160, 21 to 25 μm for the transparent PET film 150, 4 to 6 μm for the IR-blocking adhesive layer 140, 23 to 27 μm for the UV-blocking film 130, 8 to 10 μm for the transparent adhesive layer 120, and 21 to 25 μm for the release film 110.
[0036] In this example, the heat-shielding hard coat layer 160 was formed to be 2 μm thick, the transparent PET film 150 to be 23 μm thick, the IR-blocking adhesive layer 140 to be 6 μm thick, the UV-blocking film 130 to be 25 μm thick, the transparent adhesive layer 120 to be 8 μm thick, and the release film 110 to be 23 μm thick.
[0037] Fig. 2 is a flow chart showing a method for manufacturing a first semi-finished product of a window film according to an embodiment of the present invention. As shown in Fig. 3, the method for manufacturing a first semi-finished product of a window film according to an embodiment of the present invention includes a step of supplying a UV blocking film (S100), a step of forming an IR blocking adhesive layer (S110), a drying and curing step (S120), a step of supplying a transparent PET film (S130), a step of laminating (S140), and a step of winding (S150).
[0038] First, a UV blocking film supply step (S100) is performed in which a UV blocking film 130 that blocks ultraviolet rays is supplied, and an IR blocking adhesive layer formation step (S110) is performed in which an adhesive layer is formed on the upper surface of the UV blocking film 130. The IR blocking adhesive layer 140 is formed by applying an acrylic type adhesive, and can block a portion of the visible light contained in sunlight, and can also function as an adhesive layer by adding a material with a high heat blocking rate.
[0039] Next, a drying and curing step (S120) is performed to dry and cure the IR-blocking adhesive layer 140, and a transparent PET film supplying step (S130) is performed to supply a transparent PET film 150 on the upper surface of the first color adhesive layer 140. A laminating step (S140) is performed in which the lower surface of the transparent PET film 150 is adhered to the IR-blocking adhesive layer 140 to produce a first semi-finished product 10, which is then wound up in a winding step (S150).
[0040] 3 is a flow chart showing a method for manufacturing a secondary semi-finished product of a window film according to an embodiment of the present invention. As shown in FIG. 3, the method for manufacturing a secondary semi-finished product of a window film according to an embodiment of the present invention includes a step of supplying a primary semi-finished product 10 (S200), a step of forming a heat-shielding hard coat layer (S210), a step of drying and curing (S220), a step of forming a transparent adhesive layer (S230), a step of drying and curing (S240), a step of supplying a release film 110 (S250), a step of laminating (S260), and a step of winding (S270).
[0041] First, a first semi-finished product supply step (S300) is performed in which a first semi-finished product 10 is supplied, a heat-shielding hard-coat layer formation step (S210) is performed in which a heat-shielding hard-coat layer 160 is formed on the upper surface of a transparent PET film 150, and a drying and curing step (S220) is performed in which the heat-shielding hard-coat layer 160 is dried by hot air and cured by UV.
[0042] After the drying and curing step (S220), a transparent adhesive layer forming step (S230) is performed in which the transparent adhesive layer 120 is formed on the lower surface of the UV blocking film 130, and a drying and curing step (S240) is performed in which the transparent adhesive layer 120 is dried and cured.
[0043] A release film supply step (S250) is performed in which a release film 110 is supplied to be positioned on the underside of the transparent adhesive layer 120 to protect the transparent adhesive layer 120, and a lamination step (S260) is performed in which the release film 110 is laminated to the transparent adhesive layer 120 to produce a secondary semi-finished product 20, which is then wound up in a winding step (S270).
[0044] The secondary semi-finished product 20 stored in a wound state is fed to a slitting device, cut to a predetermined length, and after a rewinding process is packaged and shipped to the customer in the form of a finished product.
[0045] FIG. 4 is a cross-sectional view of a first semi-finished product 10 and a second semi-finished product 20 of a window film according to an embodiment of the present invention.
[0046] Fig. 5 is an explanatory diagram of a method for measuring the spectral transmittance of a window film according to the present invention. The spectral transmittance (regular transmittance) was measured using a SolidSpec-3700DV (manufactured by Shimadzu Corporation) in the arrangement shown in Fig. 5. The results of the first measurement are shown in Fig. 6.
[0047] Figure 6 shows data on the spectral transmittance of the window film of the present invention. It shows that the ultraviolet region of 250 nm to 400 nm is suppressed by 100%, and the visible light region of about 450 nm to about 650 nm shows a transmittance of about 80%.
[0048] It exhibits a transmittance of approximately 1% to approximately 35% in the wide infrared region from approximately 800nm to 2000nm. In other words, it exhibits a suppression / blocking effect of approximately 65% to approximately 99%. This remarkable suppression / blocking effect over a wide infrared region from approximately 800nm, which is a short wavelength in the infrared region, provides an effect of blocking the effects of infrared rays and heat.
[0049] Figures 7 and 8 show the same test content as Figure 6, but were conducted at a different location and on a different date (at the General Foundation Building Materials Testing Center) just to be sure. In this test, in accordance with JIS A 5759 (films for architectural glazing), a spectrophotometer was used to measure the spectral transmittance and spectral reflectance for each wavelength, and the ultraviolet transmittance, visible light transmittance, visible light reflectance, solar transmittance, solar reflectance, shading coefficient, solar heat gain coefficient, and overall heat transfer coefficient were calculated. The solar heat removal rate was also calculated by subtracting the solar heat gain coefficient from 1, and the solar absorptance was calculated using equation (1). Normal emissivity was calculated by measuring the spectral reflectance in the wavelength range of 5.5μm to 25μm, in accordance with JIS R 3106 (Test methods for transmittance, reflectance, and emissivity of plate glass and calculation methods for solar heat gain coefficient of architectural plate glass), Annex JB (normative) Measurement methods for spectral reflectance and spectral transmittance in the wavelength range of room temperature thermal radiation, and calculation methods for normal emissivity, JB.2 Calculation method for normal emissivity. In calculating normal emissivity, the value for the wavelength 23.3μm was used for the spectral reflectance in the wavelength range of 25.2μm to 50.0μm. TIFF2025150982000004.tif32166
[0050] Figure 7 shows the measurement results of the spectral transmittance and spectral reflectance from the above test. Figure 8 shows the measurement data for spectral transmittance and spectral reflectance at each wavelength. The results are similar to those in Figure 6, showing 100% suppression in the ultraviolet region from 300 nm to 400 nm. A transmittance of approximately 80% is shown in the visible light region from approximately 400 nm to approximately 650 nm. Additionally, a transmittance of approximately 1% to approximately 35% is shown in the wide infrared region from approximately 800 nm to 2000 nm. In other words, a suppression / blocking effect of approximately 60% to approximately 99% is demonstrated. This remarkable suppression / blocking effect over a wide range of infrared light, from approximately 800 nm, which is a short wavelength in the infrared region, provides an effective effect of blocking the effects of infrared light and heat.
[0051] The technical concept of the present invention should not be interpreted as being limited to the above-described embodiments.
[0052] It goes without saying that the scope of application is varied, and various modifications can be made by those skilled in the art without departing from the spirit of the present invention as claimed in the claims. Therefore, as long as such improvements and modifications are obvious to those skilled in the art, they will fall within the scope of protection of the present invention. [Explanation of symbols]
[0053] 10 Primary semi-finished products 20 Secondary semi-finished products 100 window films 110 Release film 120 Transparent adhesive layer 130 UV blocking film 140 IR blocking adhesive layer 150 transparent PET film 160 Heat-shielding hard coat layer
Claims
1. A window film comprising at least a heat-shielding hard coat layer formed by applying a dispersed tin-doped indium oxide (ITO) additive to the upper surface of a transparent PET film.
2. a heat-shielding hard coat layer (160) formed by applying a dispersed tin-doped indium oxide (ITO) additive to the upper surface of a transparent PET film (150); a transparent PET film (150) disposed on the upper surface of the heat-blocking hard coating layer (160); an IR-blocking adhesive layer (140) for blocking part of the visible light range and infrared light, to which a diimmonium dye for near-infrared blocking has been added; A UV blocking film (130) made of PET film material to block ultraviolet rays; an adhesive layer disposed under the UV blocking film, the adhesive layer having an adhesive applied to a predetermined height and contacting the glass window; A window film comprising:
3. The UV blocking film (130) 3. The window film according to claim 2, wherein the PET chips are melted after adding an ultraviolet blocking agent thereto and then processed into a film.
4. The heat-shielding hard coat layer (160) is 4. The window film according to claim 1, wherein dispersed ITO (Indium Tin Oxide) is mixed with acrylic resin at a certain ratio and applied to the upper surface of the transparent PET film.
5. 5. The window film according to claim 1, wherein at least the heat-blocking hard coat layer (160), the transparent PET film (150), the IR-blocking adhesive layer (140), and the UV-blocking film (130) are laminated in this order.