Car roof externally-pasted glass film with thermochromism function

Abstract

The utility model discloses a car roof externally-attached glass film, in particular to a car roof externally-attached glass film with a thermochromism function, and the layered structure of the car roof externally-attached glass film comprises a release film layer, a pressure-sensitive adhesive layer, a VO2 film layer and a TPU (Thermoplastic Polyurethane) base material layer which are compounded in sequence. According to the utility model, the technical problem that infrared radiation (heat) entering a vehicle can be adjusted by the externally-pasted glass film on the vehicle roof according to the environment temperature condition is solved. The heat insulation plate has good heat stability, so that the heat insulation effect can be effectively realized for a long time; in addition, the visible light transmissivity of the light guide plate is relatively high.

Description

Technical Field

[0001] The utility model relates to a glass film for sticking on the outside of a vehicle roof, in particular to a glass film for sticking on the outside of a vehicle roof with a thermochromic function. Background Art

[0002] Compared to traditional, small car sunroofs, full-glass roofs and panoramic sunroofs have earned widespread acclaim for their exceptional transparency and high light transmittance. They not only create a more spacious interior, but also offer passengers a view of the boundless sky just by looking up. Drivers can fully appreciate the stunning interplay of light and shadow, adding a touch of romance and delight, making them highly popular with consumers. However, every coin has its downsides. While large panoramic sunroofs and full-glass roofs enhance the driving experience, they also present some significant challenges, such as poor sun protection and fragility. This is particularly true during the scorching summer months, when intense sunlight pours directly onto the roof. Even with the air conditioning set to its lowest setting, the expanse of glass overhead can still feel like a blazing oven, causing significant headaches.

[0003] To address this issue, roof film products have emerged. Roof film is divided into external and internal films. Internal film, made of PET, is applied to the inside of the roof glass. It generally provides sun protection and heat insulation by reflecting light, effectively blocking UV rays and some heat, reducing damage to objects and people inside the vehicle due to UV exposure. Furthermore, enhancing safety is a key feature of roof film, which is why external film has emerged. External film, made of TPU, effectively reduces external impact on the roof glass, significantly reducing the risk of shattering. As a result, external film is becoming increasingly popular with customers.

[0004] Currently, roof window films primarily achieve their insulation by absorbing heat from sunlight, often by adding heat-absorbing inorganic materials. However, these films reach saturation after absorbing a certain amount of heat and are unable to absorb any more. Over time, this saturation decreases, allowing heat to flow into the vehicle, raising the interior temperature and compromising insulation effectiveness.

[0005] Therefore, the applicant proposed the present utility model. Summary of the Invention

[0006] The purpose of the utility model is to solve the above-mentioned deficiencies in the prior art and to provide a roof glass film with a thermochromic function.

[0007] In order to achieve the above-mentioned purpose, the utility model designs a roof glass film with thermochromic function, whose layered structure includes a release film layer, a pressure-sensitive adhesive layer, a VO2 film layer and a TPU substrate layer compounded in sequence.

[0008] The aforementioned thermochromic roof glass film features a layered structure in which the vanadium dioxide (VO2) in the VO2 film undergoes a reversible metal-to-semiconductor phase transition at approximately 68°C. This rapid transition from a low-temperature phase (M, monoclinic P21 / c) to a high-temperature phase (R, tetragonal P42 / mnm) results in a rapid shift from high transmittance to high reflectivity in the infrared region. The color of the VO2 film changes from a slightly yellowish to brownish color before and after the phase transition. Therefore, this roof glass film can regulate the amount of infrared radiation (heat) entering the vehicle interior based on ambient temperature, achieving a thermal insulation effect.

[0009] In addition, although the phase change of the above-mentioned vanadium dioxide (VO2) is accompanied by a change in crystal symmetry, only a small volume change (about 1%) occurs in the unit cell, so the above-mentioned roof glass film has good thermal stability.

[0010] In the above-mentioned thermochromic roof glass film, the thickness of the VO2 film layer is preferably 125nm to 130nm.

[0011] The above-mentioned roof glass film with thermochromic function has a structure in which the material of the TPU substrate layer is preferably aliphatic TPU, the surface hardness is preferably 80A~93A, the visible light transmittance is preferably above 90%, the elongation at break is preferably above 300%, the haze is preferably below 2%, and the thickness is preferably 100μm~300μm.

[0012] In the above-mentioned roof glass film with thermochromic function, the material of the pressure-sensitive adhesive layer in its structure is preferably transparent acrylic pressure-sensitive adhesive or polyurethane pressure-sensitive adhesive, the visible light transmittance is preferably above 90%, and the thickness is preferably 20μm to 50μm.

[0013] In the above-mentioned thermochromic roof glass film, the release film layer is preferably a PET release film, and more preferably a transparent PET release film. The haze is preferably less than 1.5%, the visible light transmittance is preferably more than 90%, the release force is preferably within 20 g / inch, and the thickness is preferably 23 μm to 50 μm.

[0014] Preferably, the above-mentioned roof glass film with thermochromic function further comprises a SiO2 film layer in its structure, which is compounded to the surface of the VO2 film layer on the side away from the TPU substrate layer.

[0015] The refractive index of the VO2 film layer in the aforementioned roof glass film is relatively large (greater than 2), resulting in a relatively low visible light transmittance of the roof glass film, affecting the light and vision inside the car. This preferred technical solution can effectively solve this problem by compounding a low-refractive-index anti-reflective SiO2 film layer on the VO2 film layer.

[0016] The thickness of the SiO2 film layer is further preferably selected to be 130nm to 140nm.

[0017] Preferably, the above-mentioned roof glass film with thermochromic function further comprises: a protective film layer, which is compounded to the surface of the TPU substrate layer on the side away from the VO2 film layer.

[0018] The material of the protective film layer is preferably transparent PET, and more preferably a PET protective film with silicone, and the thickness is preferably 23 μm to 75 μm.

[0019] Compared with the prior art, the present invention provides a thermochromic roof glass film with the following technical effects:

[0020] The utility model provides a roof glass film with thermochromic function, which can adjust the infrared radiation (heat) entering the car according to the ambient temperature. The transmittance difference ΔT at 2000nm is ΔT at ambient temperatures of 25℃ and 70℃. 2000 Difference from solar integrated transmittance ΔT sol They are 44.9% and 8.5% respectively, thus achieving the thermal insulation effect.

[0021] The utility model provides a car roof exterior glass film with a thermochromic function, which has good thermal stability and can effectively achieve a long-term heat insulation effect.

[0022] The utility model provides a roof glass film with thermochromic function, which significantly improves the visible light transmittance by compounding a low-refractive-index anti-reflective SiO2 film layer on a VO2 film layer. The visible light integral transmittance T vis，L is 67.1%, while the visible light integral transmittance T vis，H Still at 65.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the layered structure of a thermochromic glass film for a car roof;

[0024] Figure 2 This is a schematic diagram of the layered structure of another type of roof glass film with thermochromic function.

[0025] In the figure: release film layer 1, pressure-sensitive adhesive layer 2, SiO2 film layer 3, VO2 film layer 4, TPU substrate layer 5, and protective film layer 6. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention. Example 1:

[0027] like Figure 1 As shown, as an embodiment of the present invention, a roof glass film with thermochromic function provided in this embodiment has a layered structure including a release film layer 1, a pressure-sensitive adhesive layer 2, a VO2 film layer 4, a TPU substrate layer 5 and a protective film layer 6 that are compounded in sequence.

[0028] The specific preparation process of the above-mentioned roof glass film is as follows:

[0029] In step 1, a CA-V(IV) colloid was deposited onto a quartz glass or silicon substrate using a spin coating method. The coating was dried at 60°C for 10 minutes and then calcined at 500°C in an argon atmosphere for 1 hour to convert the CA-V(IV) colloid into a VO2 film with a thickness of 125 nm.

[0030] Step 2: The VO2 film prepared in step 1 is covered on one side of a 100 μm thick TPU substrate (49510, Argotec) by thermal bonding technology;

[0031] Step 3: Apply pressure-sensitive adhesive (Henkel, Loctite 8087) on the surface of a 23 μm thick transparent PET release film (Vanrun Optoelectronics, C05-T1) and dry it at 110°C for 2 min to form a pressure-sensitive adhesive layer with a dry adhesive thickness of 20 μm. Then, apply the pressure-sensitive adhesive layer on the surface of the VO2 film prepared in step 2.

[0032] Step 4: Cover the other surface of the TPU substrate with a 23 μm thick PET protective film (Yihua Dongli, G01);

[0033] Step 5: Place the semi-finished product in step 4 into a 50°C curing chamber for 72 hours to obtain the finished product of the roof glass film. Example 2:

[0034] As a second embodiment of the present invention, a roof glass film with thermochromic function provided in this embodiment has a layered structure and a preparation process consistent with those of the aforementioned embodiment 1.

[0035] However, in this embodiment, the thickness of the VO2 film is 128 nm; the thickness of the TPU substrate (49510, Argotec) is 200 μm; the thickness of the dry adhesive obtained by curing the pressure-sensitive adhesive (Henkel, Loctite 8087) is 35 μm; the thickness of the transparent PET release film (Toray, Lumirror) is 38 μm; and the thickness of the PET protective film (Yihua Toray, G01) is 50 μm. Example 3:

[0036] As the third embodiment of the present invention, a roof glass film with thermochromic function provided in this embodiment has the same layered structure and preparation process as those in the aforementioned embodiment 1.

[0037] However, in this embodiment, the thickness of the VO2 film is 130 nm; the thickness of the TPU substrate (49510, Argotec) is 300 μm; the thickness of the dry adhesive obtained by curing the pressure-sensitive adhesive (Henkel, Loctite 8087) is 50 μm; the thickness of the transparent PET release film (Toray, Lumirror) is 50 μm; and the thickness of the PET protective film (Yihua Toray, G01) is 75 μm. Example 4:

[0038] like Figure 2 As shown, as the fourth embodiment of the present utility model, a roof glass film with thermochromic function is provided in this embodiment, and its layered structure includes a release film layer 1, a pressure-sensitive adhesive layer 2, a SiO2 film layer 3, a VO2 film layer 4, a TPU substrate layer 5 and a protective film layer 6 that are compounded in sequence.

[0039] The specific preparation process of the above-mentioned roof glass film is as follows:

[0040] In step 1, CA-V(IV) colloid is deposited on a quartz glass or silicon substrate by spin coating. The coating is dried at 60°C for 10 minutes and then calcined at 500°C in an argon atmosphere for 1 hour to convert the CA-V(IV) colloid into a 125nm thick VO2 film. SiO2 colloid is then applied to the surface of the VO2 film by spin coating and then dried in an oven at 80°C for 1 hour to obtain a 255nm thick VO2 / SiO2 bilayer film.

[0041] Step 2: The VO2 / SiO2 double-layer film prepared in step 1 is covered on one side of a 100 μm thick TPU substrate (49510, Argotec) by thermal bonding technology;

[0042] Step 3: Apply pressure-sensitive adhesive (Henkel, Loctite 8087) onto a 23 μm thick transparent PET release film (Vanrun Optoelectronics, C05-T1) and dry at 110°C for 2 min to form a 20 μm thick pressure-sensitive adhesive layer. This pressure-sensitive adhesive layer is then applied to the VO2 / SiO2 double-layer film prepared in step 2.

[0043] Step 4: Cover the other surface of the TPU substrate with a 23 μm thick PET protective film (Yihua Dongli, G01);

[0044] Step 5: Place the semi-finished product in step 4 into a 50°C curing chamber for 72 hours to obtain the finished product of the roof glass film. Example 5:

[0045] As the fifth embodiment of the present invention, a roof glass film with thermochromic function provided in this embodiment has a layered structure and a preparation process consistent with those of the aforementioned embodiment 4.

[0046] However, the thickness of the VO2 / SiO2 double-layer film in this embodiment is 260 nm. Example 6:

[0047] As the sixth embodiment of the present invention, a roof glass film with thermochromic function provided in this embodiment has the same layered structure and preparation process as those of the aforementioned embodiment 4.

[0048] However, the thickness of the VO2 / SiO2 double-layer film in this embodiment is 265 nm.

[0049] Finally, a U4100 UV-visible near-infrared (UVVisNIR) spectrometer produced by Hitachi, Japan, was used to test the transmittance of the samples corresponding to each embodiment in the range of 300-2500nm (sunlight), with the sample temperatures being 25°C and 70°C respectively; the visible light integral transmittance T of the samples corresponding to each embodiment at 25°C was calculated. vis，L and the visible light integral transmittance T at 70 °C vis，H , and the difference in transmittance at the two temperatures (the transmittance difference at 2000nm ΔT 2000 Difference from solar integrated transmittance ΔT sol ) to characterize the thermochromic and optical properties of the samples in each example. See Table 1 below for details:

[0050] sample <![CDATA[T vis，L ]]> <![CDATA[T vis，H ]]> <![CDATA[ΔT 2000 ]]> <![CDATA[ΔT sol ]]> Example 1 55.6% 55.5% 44.9% 8.5% Example 2 55.6% 55.5% 44.9% 8.5% Example 3 55.6% 55.5% 44.9% 8.5% Example 4 67.1% 65.9% 42.4% 8.1% Example 5 67.1% 65.9% 42.4% 8.1% Example 6 67.1% 65.9% 42.4% 8.1%

[0051] From the table above, we can see that the difference in transmittance of VO2 / SiO2 double layer film at two temperatures (the transmittance difference at 2000nm ΔT 2000 Difference from solar integrated transmittance ΔT sol ) are slightly lower than the corresponding values ​​of VO2 single layer film, which indicates that the thermochromic performance of the double layer film is slightly reduced compared with the VO2 single layer film; however, the visible light integrated transmittance T vis，L and the visible light integral transmittance T at 70 °C vis，H They are significantly higher (more than 10%) than the corresponding values ​​of VO2 single-layer film, which indicates that the visible light transmittance of the double-layer film has been significantly improved compared with the VO2 single-layer film.

[0052] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A car roof glass film with thermochromic function, characterized by The layered structure includes a release film layer, a pressure-sensitive adhesive layer, a SiO2 film layer, a VO2 film layer and a TPU substrate layer which are compounded in sequence.

2. The thermochromic glass film for roof application according to claim 1, characterized in that: The thickness of the VO2 film layer is 125nm-130nm.

3. The thermochromic roof glass film according to claim 1, characterized in that: The thickness of the TPU substrate layer is 100 μm to 300 μm.

4. The thermochromic roof glass film according to claim 1, characterized in that: The thickness of the pressure-sensitive adhesive layer is 20 μm to 50 μm.

5. The thermochromic glass film for roof application according to claim 1, characterized in that: The thickness of the release film layer is 23 μm to 50 μm.

6. The thermochromic glass film for roof application according to claim 1, characterized in that: The thickness of the SiO2 film layer is 130nm-140nm.

7. A thermochromic roof glass film according to any one of claims 1 to 6, characterized in that It also includes: a protective film layer, which is compounded to the surface of the TPU substrate layer on the side away from the VO2 film layer.

8. The thermochromic glass film for roof application according to claim 7, characterized in that: The thickness of the protective film layer is 23 μm to 75 μm.

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