Rear vehicle window functional ink, preparation method thereof and rear vehicle window composite functional film

Abstract

The invention relates to the technical field of automobile window functional materials, in particular to rear window functional ink, a preparation method thereof and a rear window composite functional film. By combining a specific liquid crystal compound system, a functional nano material and a structured PVB base film, integration of multiple functions such as one-way visual color change, efficient heat insulation, ultraviolet protection, sound insulation and noise reduction is realized. According to the scheme, the problem that in the prior art, other performance is sacrificed for achieving a single function, or compatibility is poor due to simple function superposition is solved, and the single film material can meet multiple requirements of the automobile rear window in the aspects of privacy, heat management, durability and driving and riding comfort at the same time.

Description

Technical Field

[0001] This invention relates to the field of automotive window functional materials technology, and in particular to a rear window functional ink, its preparation method, and a rear window composite functional film. Background Technology

[0002] With the upgrading of automobile consumption, users have increasingly diversified functional requirements for rear windows. In addition to basic privacy protection, they also expect them to have excellent heat insulation and sound insulation performance, and be able to adapt to complex driving environments. Currently, PVB (polyvinyl butyral) films using cholesteric liquid crystals are already available on the market for use in automobile rear windows, utilizing their thermochromic properties to achieve visual privacy adjustment.

[0003] However, these existing technologies have significant limitations. First, they lack temperature adaptability: at high temperatures (above 70°C), the thermal motion of cholesterol liquid crystal molecules intensifies, and the helical structure is prone to disorder, leading to weakened selective reflectivity, uneven color change, or functional failure. At low temperatures (below -20°C), the viscosity of liquid crystal molecules increases significantly, the response time is drastically prolonged, and irreversible crystalline phase transitions may even occur, resulting in permanent loss of the color-changing function. Simultaneously, the softening of the PVB substrate at high temperatures further exacerbates the overall structural instability. Second, they have low functional integration: most existing products are single-function, making it difficult to effectively integrate multiple requirements such as color-changing privacy, efficient heat insulation, sound insulation and noise reduction, and UV protection. Even with functional integration, material or structural conflicts often lead to a significant decrease in performance in one aspect or affect other vehicle functions (such as interfering with the operation of the rear window heating wire or affecting the rearview mirror's field of vision). Third, poor environmental durability: When faced with actual usage conditions such as vehicle vibration and repeated wiping, existing membrane materials are prone to problems such as decreased adhesion, uneven coating or membrane damage, affecting service life and aesthetics.

[0004] Therefore, developing a rear window composite functional film that can work stably in a wide temperature range, synergistically achieve multiple functions, and has excellent environmental tolerance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a rear window functional ink and its preparation method, as well as a rear window composite functional film. By combining a specific liquid crystal compounding system, functional nanomaterials, and a structured PVB base film, multiple functions such as unidirectional visible color change, high-efficiency heat insulation, ultraviolet protection, and sound insulation and noise reduction are integrated into one.

[0006] To achieve the above objectives, the present invention provides a rear window functional ink, comprising the following components in parts by weight: The composition comprises 20-35 parts of cholesteric liquid crystal composition, 40-50 parts of acrylate emulsion, 3-5 parts of emulsifying dispersant, 0.01-0.5 parts of near-infrared blocking material, and 0.05-0.15 parts of ultraviolet blocking material. The cholesteric phase liquid crystal composition includes cholesterol nonanoate and cholesterol benzoate.

[0007] Preferably, the mass ratio of cholesterol nonanoate to cholesterol benzoate is 2-3:1.

[0008] Preferably, it also includes 0.5-1 parts of polyethylene glycol monomethyl ether and 0.05-0.15 parts of 7-hydroxycoumarin.

[0009] Preferably, it also includes 5-8 parts of microcrystalline wax, 2-4 parts of polysiloxane modifier, and 0.3-0.8 parts of polyacrylamide.

[0010] The present invention also provides a method for preparing the aforementioned rear window functional ink, comprising the following steps: S1. Mix the acrylic emulsion with an emulsifying dispersant to form an aqueous system; S2. The molten cholesteric liquid crystal composition is mixed with an aqueous system to form a liquid crystal emulsion; S3. Mix the liquid crystal emulsion with the remaining components to obtain the rear window functional ink.

[0011] The present invention also provides a rear window composite functional film, comprising a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the rear window functional ink; the PVB base film comprises the following components in parts by weight: 82-88 parts of PVB resin, 12-18 parts of plasticizer, and 10-14 parts of damping agent.

[0012] Preferably, the damping agent is selected from ethylene-vinyl acetate micro powder.

[0013] Preferably, the PVB base film further includes 0.1-0.3 parts of antioxidant, 0.1-0.35 parts of UV stabilizer, 0.2-0.4 parts of insulating modifier, and 0.1-0.3 parts of infrared blocker.

[0014] The present invention also provides a method for preparing the aforementioned rear window composite functional film, comprising the following steps: (1) Plasma treatment of the PVB base film; (2) Apply the rear window functional ink to the surface of the plasma-treated PVB base film; (3) The coated film is cured in sections to obtain the rear window composite functional film.

[0015] Preferably, in step (2), the coating amount is 9-11 g / m². 2 .

[0016] The beneficial effects of this invention are as follows: (1) The rear window functional ink and composite functional film provided by the present invention integrate multiple functions such as unidirectional visible color change, high-efficiency heat insulation, ultraviolet protection and sound insulation by combining a specific liquid crystal compounding system, functional nanomaterials and structured PVB base film. This solution overcomes the problems of sacrificing other performances to achieve a single function in traditional technologies, or poor compatibility caused by simple function superposition, so that a single film material can simultaneously meet the multiple needs of automotive rear windows in terms of privacy, thermal management, durability and driving comfort.

[0017] (2) By using a specific ratio of cholesterol nonanoate and cholesterol benzoate as the color-changing core of the ink, and combining it with a suitable base film plasticizing system, the stable operating temperature range of the thermochromic function is effectively broadened. This material design helps to improve the structural stability of the liquid crystal state at high temperatures and its fluidity at low temperatures, thereby enhancing the reliability of the product in complex climatic environments and enabling it to maintain a consistent color-changing response and visual effect over a wider temperature range.

[0018] (3) Introducing ethylene-vinyl acetate micropowder as a damping component into the PVB base film, combined with plasma surface treatment before base film coating, helps to improve the mechanical toughness and interfacial bonding strength of the composite film. This structural design aims to enhance the film material's ability to dissipate vibration and its resistance to physical wiping, thereby improving the product's durability in actual use scenarios.

[0019] (4) The preparation process of the present invention includes stepwise emulsification and dispersion of ink, plasma formation of base film, and segmented thermal curing after coating, which helps to achieve uniform distribution and stable bonding of functional components in the film layer. This process design improves the consistency of product performance. At the same time, the insulating modifier added to the formula takes into account compatibility with vehicle heating elements, which helps to ensure driving visibility safety.

[0020] (5) The raw materials used in this invention are all commonly used industrial materials. The preparation process does not involve special harsh conditions or the use and emission of harmful substances. It takes into account the feasibility of production, cost controllability and compliance with environmental protection requirements, and has good application prospects. Detailed Implementation

[0021] This invention provides a rear window functional ink, comprising the following components in parts by weight: The composition comprises 20-35 parts of cholesteric liquid crystal composition, 40-50 parts of acrylate emulsion, 3-5 parts of emulsifying dispersant, 0.01-0.5 parts of near-infrared blocking material, and 0.05-0.15 parts of ultraviolet blocking material. The cholesteric phase liquid crystal composition includes cholesterol nonanoate and cholesterol benzoate.

[0022] In this invention, the mass ratio of cholesterol nonanoate to cholesterol benzoate is 2-3:1.

[0023] In this invention, the emulsifying dispersant is selected from C8 fatty alcohol polyoxyethylene ether (CAS No.: 68131-39-5); the near-infrared blocking material is selected from nano indium tin oxide; and the ultraviolet blocking material is selected from modified nano zinc oxide.

[0024] In this invention, the particle size of nano-indium tin oxide is 45-55 nm.

[0025] In this invention, the modified nano zinc oxide is stearic acid-coated modified nano zinc oxide with a particle size of 15-25 nm.

[0026] In this invention, it also includes 0.5-1 parts of polyethylene glycol monomethyl ether and 0.05-0.15 parts of 7-hydroxycoumarin.

[0027] In this invention, the molecular weight of polyethylene glycol monomethyl ether is 1800-2200.

[0028] The present invention also includes 5-8 parts of microcrystalline wax, 2-4 parts of polysiloxane modifier and 0.3-0.8 parts of polyacrylamide.

[0029] The present invention also provides a method for preparing the aforementioned rear window functional ink, comprising the following steps: S1. Mix the acrylic emulsion with an emulsifying dispersant to form an aqueous system; S2. The molten cholesteric liquid crystal composition is mixed with an aqueous system to form a liquid crystal emulsion; S3. Mix the liquid crystal emulsion with the remaining components to obtain the rear window functional ink.

[0030] In this invention, in S1, the mixing temperature is 40-45℃, the rotation speed is 450-550rpm, and the time is 10-20min.

[0031] In this invention, in step S2, the cholesteric liquid crystal composition is heated to 60-65°C to melt, thereby obtaining a molten cholesteric liquid crystal composition.

[0032] In this invention, in step S2, after mixing, the mixture is sheared at a speed of 1800-2200 rpm for 25-35 minutes to form a liquid crystal emulsion.

[0033] In this invention, in step S3, the liquid crystal emulsion is cooled to 35-40°C and mixed with the remaining components. After mixing, the mixture is degassed for 5-15 minutes under a vacuum of -0.06 to -0.1 MPa to obtain the rear window functional ink.

[0034] The present invention also provides a rear window composite functional film, comprising a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the rear window functional ink; the PVB base film comprises the following components in parts by weight: 82-88 parts of PVB resin, 12-18 parts of plasticizer, and 10-14 parts of damping agent.

[0035] In this invention, the degree of polymerization of the PVB resin is 1700-1900.

[0036] In this invention, the plasticizer is selected from triethylene glycol di-2-ethylhexanoate (3GO), tetraethylene glycol di-2-ethylhexanoate (4GO), diethylene glycol di-2-ethylhexanoate (2GO), triethylene glycol diheptanoate, triethylene glycol dioctanoate, triethylene glycol dinonanoate, diethylene glycol dinonanoate, tetraethylene glycol diheptanoate, tetraethylene glycol bis-n-heptanoate (4G7), dibutyl sebacate (DBS), triisononyl trimellitate (TINTM), N-ethyltoluenesulfonamide, di(2-ethylhexyl) phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dibutyl phthalate (DBP), and diheptyl phthalate (DHP). The plasticizer comprises at least one of dipropyl phthalate, diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), di(C9-C11)alkyl phthalate, di(2-ethylhexyl) adipate (DOA), diisononyl adipate (DINA), diisodecyl adipate (DIDA), di(2-ethylhexyl) azelate (DOZ), di(2-ethylhexyl) sebacate (DOS), di-n-hexyl adipate, triisodecyl trimellitate (TIDTM), trioctyl trimellitate, and tricresyl phosphate (TCP); preferably, the plasticizer comprises triethylene glycol di-2-ethylhexanoate (3GO) and dibutyl sebacate (DBS), wherein the mass ratio of 3GO to DBS is 4-6:1.

[0037] In this invention, the damping agent is selected from ethylene-vinyl acetate micro powder; the particle size of the ethylene-vinyl acetate micro powder is 1-2 μm, and the mass fraction of vinyl acetate in the ethylene-vinyl acetate micro powder is 31-35%.

[0038] In this invention, the PVB base film further includes 0.1-0.3 parts of antioxidant, 0.1-0.35 parts of UV stabilizer, 0.2-0.4 parts of insulating modifier, and 0.1-0.3 parts of infrared blocker.

[0039] In this invention, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076, antioxidant 245, antioxidant 1098, and antioxidant 1135; preferably, the antioxidant includes antioxidant 1010 and antioxidant 245, and the mass ratio of antioxidant 1010 to antioxidant 245 is 0.15-0.25:0.05-0.15.

[0040] In this invention, the UV absorber is selected from at least one of UV absorbers UV-326, UV absorber UV-329, UV absorber UV-328, UV absorber UV-327, and UV absorber UV-1130; preferably, the UV absorber includes UV absorber UV-328 and UV absorber UV-1130, and the mass ratio of UV absorber UV-328 to UV absorber UV-1130 is 0.15-0.25:0.1-0.2.

[0041] In this invention, the insulating modifier is selected from polysiloxane modifiers.

[0042] In this invention, the infrared blocking agent is selected from at least one of indium tin oxide, antimony tin oxide, zinc aluminum oxide, lanthanum hexaboride, and zinc oxide, preferably indium tin oxide.

[0043] The present invention also provides a method for preparing the aforementioned rear window composite functional film, comprising the following steps: (1) Plasma treatment of the PVB base film; (2) Apply the rear window functional ink to the surface of the plasma-treated PVB base film; (3) The coated film is cured in sections to obtain the rear window composite functional film.

[0044] In this invention, step (1) of the preparation method of PVB base film includes the following steps: mixing the components of PVB base film at 120-130℃ for 20-30 min to obtain a premix; melting and plasticizing the premix through a twin-screw extruder (setting the temperature of the first zone of the screw to be 125-135℃, the temperature of the second zone to be 135-145℃, the temperature of the third zone to be 145-155℃, and the temperature of the die head to be 160-165℃), and calendering it into a film material with a thickness of 0.22-0.25 mm by a three-roll calender (setting the temperature of the lower roll to be 150-160℃, the temperature of the middle roll to be 155-165℃, the temperature of the upper roll to be 160-170℃, and the traction speed to be 2-3 m / min); and then, using a combination of air cooling (air temperature 25-30℃) and water cooling (water temperature 20-25℃) to double-cool the film material to obtain PVB base film.

[0045] In this invention, in step (1), the plasma treatment power is 300-400W and the time is 30-40s.

[0046] In this invention, in step (2), a doctor blade coating method is used for coating, with the doctor blade gap set to 0.08-0.09 mm, the coating speed to 1-3 m / min, and the coating amount to 9-11 g / m. 2 .

[0047] In this invention, step (3) includes segmented curing: first curing at 40-50℃ for 8-12 min, then curing at 60-70℃ for 18-22 min, and finally curing at 45-55℃ for 13-17 min.

[0048] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0049] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0050] In the following embodiments and comparative examples of the present invention, the specifications or sources of the raw materials used are as follows: (1) Rear window functional ink Stearic acid-coated modified nano-zinc oxide: particle size 20nm, purchased from Maclean's reagents; polysiloxane modifier: Evonik 6440 polysiloxane modifier; (2) PVB base film Ethylene-vinyl acetate micro powder: particle size of 1.5μm, vinyl acetate mass fraction of 33%; Insulation modifier: Evonik 6440 polysiloxane modifier.

[0051] Example 1 This embodiment provides a rear window functional ink, comprising the following components in parts by weight: The composition includes 18 parts of cholesterol nonanoate, 7 parts of cholesterol benzoate, 45 parts of acrylate emulsion, 4 parts of C8 fatty alcohol polyoxyethylene ether, 0.025 parts of nano indium tin oxide (particle size 50nm), 0.1 parts of nano zinc oxide modified with stearic acid, 0.8 parts of polyethylene glycol monomethyl ether (molecular weight 2000), 0.1 parts of 7-hydroxycoumarin, 6 parts of microcrystalline wax, 3 parts of polysiloxane modifier, and 0.5 parts of polyacrylamide.

[0052] This embodiment also provides a method for preparing the above-mentioned rear window functional ink, including the following steps: The acrylate emulsion was heated to 42°C, and C8 fatty alcohol polyoxyethylene ether was added. The mixture was stirred at 500 rpm for 15 minutes to form an aqueous phase system.

[0053] Cholesterol nonanoate and cholesterol benzoate were mixed, heated to 63°C to melt, and then dropped into an aqueous system. The mixture was sheared at 2000 rpm for 30 minutes to form a liquid crystal emulsion.

[0054] The liquid crystal emulsion was cooled to 38°C, and polyethylene glycol monomethyl ether, 7-hydroxycoumarin, nano-indium tin oxide, and stearic acid-coated nano-zinc oxide were added sequentially. The mixture was stirred at 800 rpm for 25 min, then microcrystalline wax, polysiloxane modifier, and polyacrylamide were added sequentially. The mixture was stirred at 600 rpm for 20 min, and finally vacuum degassed at -0.08 MPa for 10 min to obtain the rear window functional ink.

[0055] This embodiment also provides a rear window composite functional film, comprising a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the aforementioned rear window functional ink; the PVB base film comprises the following components in parts by weight: 85 parts of PVB resin (degree of polymerization 1800), 17 parts of plasticizer (including 14 parts of 3GO and 3 parts of DBS), 12 parts of ethylene-vinyl acetate micro powder, 0.3 parts of antioxidant (0.2 parts of antioxidant 1010 and 0.1 parts of antioxidant 245), 0.35 parts of UV absorber (0.2 parts of UV-328 and 0.15 parts of UV-1130), 0.3 parts of insulation modifier, and 0.1 parts of infrared blocking agent (indium tin oxide).

[0056] This embodiment also provides a method for preparing the above-mentioned rear window composite functional film, including the following steps: The components of the PVB base film were stirred and mixed at 125°C for 25 minutes to obtain a premix. The premix was then melted and plasticized in a twin-screw extruder (screw zone 1 temperature 130°C, zone 2 temperature 140°C, zone 3 temperature 150°C, and die head temperature 162°C), and then fed into a three-roll calender (lower roll temperature 155°C, middle roll temperature 160°C, upper roll temperature 165°C, and traction speed 2.5 m / min) to calender a film with a thickness of 0.23 mm. The film was then subjected to dual cooling using a combination of air cooling (air temperature 28°C) and water cooling (water temperature 22°C) to obtain the PVB base film.

[0057] The PVB base film was subjected to plasma treatment (350W power, 35s time); the rear window functional ink was then applied to the plasma-treated PVB base film surface using a doctor blade coating method, with a doctor blade gap of 0.085mm, a coating speed of 2m / min, and a coating amount of 10g / m³. 2The coated film is then placed in a drying oven for segmented curing (first cured at 45℃ for 10 minutes, then cured at 65℃ for 20 minutes, and finally cured at 50℃ for 15 minutes) to obtain the rear window composite functional film.

[0058] Example 2 This embodiment provides a rear window functional ink, comprising the following components in parts by weight: The composition includes 16 parts cholesterol nonanoate, 8 parts cholesterol benzoate, 42 parts acrylate emulsion, 3.5 parts C8 fatty alcohol polyoxyethylene ether, 0.25 parts nano indium tin oxide (particle size 50nm), 0.1 parts stearic acid-coated modified nano zinc oxide, 0.6 parts polyethylene glycol monomethyl ether (molecular weight 2000), 0.1 parts 7-hydroxycoumarin, 5.5 parts microcrystalline wax, 2.5 parts polysiloxane modifier, and 0.4 parts polyacrylamide.

[0059] This embodiment also provides a method for preparing the above-mentioned rear window functional ink, which is basically the same as that in Example 1, except that the melting temperature of cholesterol nonanoate and cholesterol benzoate is 60°C and the shearing speed is 1800 rpm.

[0060] This embodiment also provides a rear window composite functional film, comprising a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the aforementioned rear window functional ink; the PVB base film comprises the following components in parts by weight: 83 parts of PVB resin (degree of polymerization 1700), 16 parts of plasticizer (including 13 parts of 3GO and 3 parts of DBS), 12 parts of ethylene-vinyl acetate micro powder, 0.25 parts of antioxidant (0.15 parts of antioxidant 1010 and 0.1 parts of antioxidant 245), 0.3 parts of UV absorber (0.18 parts of UV-328 and 0.12 parts of UV-1130), 0.3 parts of insulation modifier, and 0.1 parts of infrared blocking agent (indium tin oxide).

[0061] This embodiment also provides a method for preparing the above-mentioned rear window composite functional film, which is basically the same as that in Embodiment 1, except that the following modifications are made: the temperature of the screw zone 1 is 125°C, the temperature of the second zone is 135°C, the temperature of the third zone is 145°C, the temperature of the die head is 160°C, the traction speed is 2m / min, and the calendering thickness is 0.22mm.

[0062] Example 3 This embodiment provides a rear window functional ink, which is exactly the same as that in Embodiment 1.

[0063] This embodiment also provides a method for preparing the above-mentioned rear window functional ink, which is exactly the same as that in Embodiment 1.

[0064] This embodiment also provides a rear window composite functional film, comprising a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the aforementioned rear window functional ink; the PVB base film comprises the following components in parts by weight: 87 parts of PVB resin (degree of polymerization 1900), 15 parts of plasticizer (including 12 parts of 3GO and 3 parts of DBS), 12 parts of ethylene-vinyl acetate micro powder, 0.3 parts of antioxidant (0.2 parts of antioxidant 1010 and 0.1 parts of antioxidant 245), 0.35 parts of UV absorber (0.2 parts of UV-328 and 0.15 parts of UV-1130), 0.3 parts of insulation modifier, and 0.1 parts of infrared blocking agent (indium tin oxide).

[0065] This embodiment also provides a method for preparing the above-mentioned rear window composite functional film, which is basically the same as that in Embodiment 1, except that the following modifications are made: the mixing temperature of each component contained in the PVB base film is 128°C and the mixing time is 28 min; the segmented curing is first cured at 45°C for 12 min, then cured at 65°C for 18 min, and finally cured at 50°C for 16 min.

[0066] Example 4 This embodiment provides a rear window functional ink, comprising the following components in parts by weight: 20 parts of cholesterol nonanoate, 10 parts of cholesterol benzoate, 50 parts of acrylate emulsion, 5 parts of C8 fatty alcohol polyoxyethylene ether, 0.05 parts of nano indium tin oxide (particle size 50nm), 0.15 parts of nano zinc oxide modified with stearic acid, 1 part of polyethylene glycol monomethyl ether (molecular weight 2000), 0.1 parts of 7-hydroxycoumarin, 8 parts of microcrystalline wax, 4 parts of polysiloxane modifier, and 0.8 parts of polyacrylamide.

[0067] This embodiment also provides a method for preparing the above-mentioned rear window functional ink, which is basically the same as that in Example 1, except that the liquid crystal emulsion is cooled to 38°C, and polyethylene glycol monomethyl ether, 7-hydroxycoumarin, nano indium tin oxide, and nano zinc oxide modified by stearic acid are added in sequence. The stirring conditions are 900 rpm for 30 min.

[0068] This embodiment also provides a rear window composite functional film, including a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the aforementioned rear window functional ink; the composition of the PVB base film is exactly the same as that in Embodiment 1.

[0069] This embodiment also provides a method for preparing the above-mentioned rear window composite functional film, which is basically the same as that in Embodiment 1, except that the scraper gap is 0.09 mm and the coating amount is 11 g / m². 2 .

[0070] Example 5 This embodiment provides a rear window functional ink, which is exactly the same as that in Embodiment 1.

[0071] This embodiment also provides a method for preparing the above-mentioned rear window functional ink, which is basically the same as that in Embodiment 1, except that the vacuum degree of vacuum degassing is -0.09MPa and the time is 15min.

[0072] This embodiment also provides a rear window composite functional film, including a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the aforementioned rear window functional ink; the composition of the PVB base film is exactly the same as that in Embodiment 1.

[0073] This embodiment also provides a method for preparing the above-mentioned rear window composite functional film, which is basically the same as that in Embodiment 1, except that the following modifications are made: the traction speed is 3m / min, the calendering thickness is 0.25mm, the plasma treatment power is 400W, and the time is 40s.

[0074] Comparative Example 1 The difference between this comparative example and Example 1 is that the addition of ethylene-vinyl acetate micropowder to the PVB base film is omitted.

[0075] Comparative Example 2 The difference between this comparative example and Example 1 is that "18 parts of cholesterol nonanoate and 7 parts of cholesterol benzoate" in Example 1 are replaced with "25 parts of cholesterol nonanoate".

[0076] Experimental Example 1 The rear window composite functional films prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance comparison tests. The specific conditions and methods for each test are as follows: (1) Color-changing properties According to GB / T 33728-2017 standard, the color change response time of the sample at room temperature (25℃) and low temperature (-35℃, -30℃, -20℃) was tested to evaluate its wide temperature range response capability. (2) Optical performance Near-infrared blocking rate: According to GB / T 2680-2021 standard, the near-infrared light blocking rate in the 780-2500nm band is tested to evaluate the heat insulation effect; UV blocking rate: According to GB / T 18701-2017 standard, the UV blocking rate of UVA and UVB bands is tested to evaluate the UV protection capability; Rearview mirror visibility: evaluated in accordance with GB 15084-2022 standard.

[0077] (3) Acoustic and mechanical properties Sound insulation: The sound insulation of the 200-2000Hz frequency band was tested according to GB / T 19889.1-2005 standard; Adhesion: Performed according to GB / T 9286-1998 standard (100-cross adhesion test); Abrasion resistance: Tested according to QB / T 4463-2013 standard, the number of abrasion cycles under a 500g load is tested; Tensile strength: Tested in accordance with GB / T 1040.3-2006 standard.

[0078] (4) Environmental reliability: High temperature stability: After being placed in an environment of 85℃ (90℃ or 70℃ for some samples) for 24 hours, the retention rate of its reflectance characteristics was measured to simulate high temperature usage scenarios; Vibration resistance performance: Conduct a 100-hour vibration resistance test according to GB / T 2423.10-2019 standard and observe whether the membrane material cracks or discolors unevenly.

[0079] The test results are recorded in Table 1.

[0080] Table 1 Test Results

[0081] Therefore, the present invention adopts the above-mentioned rear window functional ink and its preparation method, as well as the rear window composite functional film, and by combining a specific liquid crystal compounding system, functional nanomaterials and structured PVB base film, it realizes the integrated function of multiple functions such as unidirectional visible color change, high-efficiency heat insulation, ultraviolet protection and sound insulation and noise reduction.

[0082] Finally, it should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rear window functional ink, characterized in that, The components include the following parts by mass: The composition comprises 20-35 parts of cholesteric liquid crystal composition, 40-50 parts of acrylate emulsion, 3-5 parts of emulsifying dispersant, 0.01-0.5 parts of near-infrared blocking material, and 0.05-0.15 parts of ultraviolet blocking material. The cholesteric phase liquid crystal composition includes cholesterol nonanoate and cholesterol benzoate.

2. The rear window functional ink according to claim 1, characterized in that, The mass ratio of cholesterol nonanoate to cholesterol benzoate is 2-3:

1.

3. The rear window functional ink according to claim 1, characterized in that, It also includes 0.5-1 parts of polyethylene glycol monomethyl ether and 0.05-0.15 parts of 7-hydroxycoumarin.

4. The rear window functional ink according to claim 1 or 3, characterized in that, It also includes 5-8 parts of microcrystalline wax, 2-4 parts of polysiloxane modifier, and 0.3-0.8 parts of polyacrylamide.

5. The method for preparing the rear window functional ink according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix the acrylic emulsion with an emulsifying dispersant to form an aqueous system; S2. The molten cholesteric liquid crystal composition is mixed with an aqueous system to form a liquid crystal emulsion; S3. Mix the liquid crystal emulsion with the remaining components to obtain the rear window functional ink.

6. A rear window composite functional film, characterized in that, It includes a PVB base film and a functional layer coated on the surface of the PVB base film; the functional layer is formed by the rear window functional ink as described in any one of claims 1-4; the PVB base film includes the following components in parts by weight: 82-88 parts of PVB resin, 12-18 parts of plasticizer, and 10-14 parts of damping agent.

7. The rear window composite functional film according to claim 6, characterized in that, The damping agent is selected from ethylene-vinyl acetate micro powder.

8. The rear window composite functional film according to claim 6, characterized in that, The PVB base film also includes 0.1-0.3 parts of antioxidant, 0.1-0.35 parts of UV stabilizer, 0.2-0.4 parts of insulating modifier, and 0.1-0.3 parts of infrared blocker.

9. The method for preparing the rear window composite functional film according to any one of claims 6-8, characterized in that, Includes the following steps: (1) Plasma treatment of the PVB base film; (2) Apply the rear window functional ink to the surface of the plasma-treated PVB base film; (3) The coated film is cured in sections to obtain the rear window composite functional film.

10. The preparation method according to claim 9, characterized in that, In step (2), the coating amount is 9-11 g / m². 2 .

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