Reversible photochromic paper pot and preparation method and application thereof

Abstract

The present application provides a reversible photochromic paper bowl and its preparation method and application, the reversible photochromic paper bowl includes paper bowl base material, isolation layer, photochromic layer and protective layer arranged in turn; the isolation layer includes a combination of polyvinyl alcohol and cationic guar gum; the photochromic layer includes a combination of a first aqueous polymer matrix and photochromic microcapsules; the protective layer includes a combination of a second aqueous polymer matrix and nanometer titanium dioxide. Through the design of the isolation layer, the photochromic layer, the protective layer and their joint action, the reversible photochromic paper bowl has light response color changing characteristics, and the response speed is fast, and the color changing performance is reversible. At the same time, the reversible photochromic paper bowl has uniform and stable color development and color change effect, excellent ultraviolet aging resistance, high modulus, strength and rigidity, excellent mechanical properties, acoustic properties, sensitivity and sound quality effect, and its preparation method is simple, which can meet the diversified performance requirements in various scenes.

Description

Technical Field

[0001] This invention belongs to the field of loudspeaker technology, specifically relating to a reversible photochromic paper cone, its preparation method, and its application. Background Technology

[0002] The speaker cone is a crucial component of a loudspeaker's sound-producing unit, its primary function being to provide an accurate frequency response. Speaker cones can be categorized by material, including paper cones, metal cones, ceramic cones, polypropylene (PP) cones, and composite material cones. Among these, paper cones are widely used due to their natural tone, low cost, and ease of processing. Traditional loudspeaker paper cones typically have a limited color palette, usually black, and offer limited functionality. In recent years, however, with the growing demand for personalized and intelligent products, paper cones with unique appearances have gradually attracted attention.

[0003] Currently, the main methods for achieving different appearance colors of speaker cones include: (1) Spray painting: This is the most commonly used method. By spraying paint onto the surface of the paper cone, various colors and patterns can be achieved. (2) Printing: Printing patterns or text onto the surface of the paper cone can achieve more complex patterns. (3) Coating: Pasting a pre-coated film onto the surface of the paper cone can achieve a more diverse visual effect, as well as a smoother appearance and stronger wear resistance. (4) Anodizing: This method is mainly for metal cones. For example, forming an oxide film on the surface of an aluminum cone can achieve colors such as gold and silver.

[0004] Traditional paper cones often only meet basic functional needs, offering little in the way of additional visual appeal or other added value. With technological advancements and increasingly diverse product demands, the concept of paper cones with unique visual effects has emerged. However, current technologies for manufacturing special-appearance paper cones generally suffer from complex processes, high costs, and insufficient stability. Furthermore, the creation of special appearances often results in a decrease in the mechanical and acoustic properties of the paper cone, sacrificing its sound quality advantages. Therefore, developing a paper cone with a special appearance that offers good stability, excellent mechanical and acoustic properties, and a simple manufacturing method is a key research focus in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a reversible photochromic paper cone, its preparation method, and its application. Through the design of the isolation layer, photochromic layer, and protective layer, as well as the synergistic effect between the layers, the reversible photochromic paper cone possesses photoresponsive color-changing characteristics, and the color-changing performance is reversible, increasing product appeal. Simultaneously, the reversible photochromic paper cone exhibits stable color-changing effects, excellent UV aging resistance, and superior mechanical, acoustic, and sound quality properties. The preparation method is simple and can meet diverse performance requirements in various scenarios.

[0006] To achieve this objective, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a reversible photochromic paper basin, the reversible photochromic paper basin comprising a paper basin substrate, an isolation layer, a photochromic layer and a protective layer arranged sequentially; the isolation layer comprises a combination of polyvinyl alcohol and cationic guar gum; the photochromic layer comprises a combination of a first aqueous polymer matrix and photochromic microcapsules; the protective layer comprises a combination of a second aqueous polymer matrix and nano-titanium dioxide.

[0008] With the development of technology, color-changing technology has been widely used in many fields, including some innovations in paper packaging materials. Photochromic technology, as an emerging technology, can change color through light or environmental changes. This invention applies photochromic technology to speaker cones, providing a reversible photochromic cone with a special appearance / visual effect, exhibiting higher visual appeal and functionality. It can provide users with more personalized and intelligent choices, meeting people's demand for personalized and intelligent products, while expanding the application scope of paper cone products, such as in smart homes, automotive interiors, and other fields.

[0009] Specifically, the reversible photochromic paper basin provided by this invention includes a paper basin substrate, and an isolation layer, a photochromic layer, and a protective layer disposed thereon. The isolation layer, on the one hand, increases the rigidity of the paper basin and improves the flatness of the paper basin substrate surface, allowing the photochromic layer to be uniformly coated on the paper basin and preventing the photochromic layer from penetrating the paper basin surface, thus reducing the weight of the paper basin and improving sensitivity; on the other hand, the isolation layer enhances the adhesion of the photochromic layer, giving the reversible photochromic paper basin high strength and interlayer bonding. The photochromic layer contains photochromic microcapsules with photoresponsive color-changing properties, causing the reversible photochromic paper basin to change color under sunlight or ultraviolet light, with a fast color-changing response, increasing the product's attractiveness; simultaneously, the photochromic microcapsules have good compatibility with the first aqueous polymer matrix, enabling good dispersion and uniform display. The protective layer ensures the uniformity and stability of the color change while guaranteeing photochromism, and can more balancedly improve the UV aging resistance of the paper cone, as well as improve the modulus, rigidity and water resistance of the paper cone, and improve the durability, stability and sound quality of the paper cone.

[0010] In summary, this invention, through the design of the isolation layer, photochromic layer, and protective layer, and the combined effect of these layers, enables the reversible photochromic paper cone to possess photoresponsive color-changing characteristics with a fast response speed and reversible color-changing performance, thus fulfilling diverse appearance requirements. Simultaneously, the reversible photochromic paper cone exhibits uniform and stable color development and color-changing effects, excellent UV aging resistance, high modulus, strength, and rigidity, and possesses excellent mechanical properties, acoustic properties, sensitivity, and sound quality. Furthermore, its preparation method is simple and can meet diverse performance requirements in various scenarios.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0012] In this invention, the isolation layer comprises a combination of polyvinyl alcohol (PVA) and cationic guar gum. The PVA possesses excellent water solubility and film-forming properties, while the cationic guar gum, as a natural polysaccharide, exhibits superior thickening and viscosity-regulating effects, effectively improving the adhesion and stability of the isolation layer. The film formed by the mixture of PVA and cationic guar gum on the surface of the paper basin substrate can fill in minor unevenness, creating a uniform and smooth surface. This not only facilitates the uniform coating of the photochromic layer, reduces its penetration into the paper basin, and lowers the coating thickness, but also improves the overall visual effect of the reversible photochromic paper basin, enhancing its aesthetic appeal.

[0013] On the other hand, the polyvinyl alcohol contains a large number of hydroxyl groups, which can firmly bond with the paper basin substrate and the photochromic layer, serving as the main bonding agent; the cationic groups in the cationic guar gum can interact with the molecules in the photochromic layer, providing stronger adhesion. Therefore, the isolation layer can enhance the adhesion and interlayer force between the photochromic layer and the surface of the paper basin substrate, ensuring that the photochromic layer can firmly adhere to the surface of the paper basin and preventing the photochromic layer from peeling or flaking due to environmental factors or friction during use. In addition, the isolation layer can also reduce the impact of the paper basin's water absorption or other adverse factors on the photochromic layer, ensuring the stability and durability of the photochromic layer.

[0014] Preferably, the mass ratio of polyvinyl alcohol to cationic guar gum in the isolation layer is (2-40):1, for example, it can be 2.5:1, 3:1, 5:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 28:1, 30:1, 32:1, 35:1 or 38:1, etc., and more preferably (5-30):1.

[0015] Preferably, the thickness of the isolation layer is 5-20 μm, for example, it can be 6 μm, 8 μm, 10 μm, 12 μm, 15 μm or 18 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0016] Preferably, the isolation layer is obtained by coating an isolation coating onto a paper basin substrate and drying it, the isolation coating comprising a combination of an aqueous solution of polyvinyl alcohol and an aqueous solution of cationic guar gum.

[0017] Preferably, the polyvinyl alcohol content in the aqueous solution is 5-10% by mass, for example, 6%, 7%, 8% or 9%, and specific values ​​between the above values ​​are not exhaustively listed here for space limitations and for the sake of brevity.

[0018] Preferably, the cationic guar gum aqueous solution contains 1-5% cationic guar gum by mass, for example, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0019] Preferably, the mass ratio of the polyvinyl alcohol aqueous solution to the cationic guar gum aqueous solution is (2-4):1, for example, it can be 2.2:1, 2.4:1, 2.5:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.5:1, 3.6:1 or 3.8:1, etc.

[0020] In this invention, the photochromic layer comprises a combination of a first aqueous polymer matrix and photochromic microcapsules. The photochromic microcapsules are photochromic powder materials obtained by encapsulating reversible photochromic materials within microcapsules (shells).

[0021] Since most reversible photochromic materials (referred to as "photochromic powder") are oil-soluble, while the surface of the paper basin system is hydrophilic, the selection of the dispersion system is crucial. It is essential to ensure that the reversible photochromic material can be uniformly dispersed in the system, while also ensuring that the dispersion system can effectively bond with the paper basin surface to guarantee its stability. Therefore, this invention employs photochromic microcapsules containing reversible photochromic material, thereby improving the oil-soluble nature of the photochromic powder and enabling it to be uniformly dispersed in a first aqueous polymer matrix.

[0022] Preferably, the reversible photochromic material includes any one or a combination of at least two of the following: spiropyran compounds, spiroxazine compounds, diarylethylene compounds, and azobenzene compounds.

[0023] In this invention, the specific types of reversible photochromic materials and photochromic microcapsules are not specifically limited. Photochromic microcapsules with corresponding color-changing effects can be selected according to the appearance and color display requirements of the paper basin product, such as photochromic microcapsules of different colors such as blue, purple, orange, red, tangerine, and green.

[0024] In this invention, the photochromic microcapsules can be commercially available products, such as the photochromic microcapsule powder (MC powder) from Tianjin Fuxin Sunshine Technology Co., Ltd.

[0025] In this invention, the dispersion system of the photochromic layer is a first aqueous polymer matrix. On the one hand, it has good compatibility with the photochromic microcapsules, enabling the microcapsules to be uniformly dispersed within it, resulting in uniform color development of the photochromic layer under light irradiation. On the other hand, the first aqueous polymer matrix exhibits excellent compatibility and bonding strength with the paper basin substrate, the isolation layer, and the protective layer, particularly ensuring stable bonding between the photochromic microcapsules and the paper basin system, and ensuring tight adhesion between the photochromic layer and the paper basin substrate (including the isolation layer). Furthermore, the first aqueous polymer matrix demonstrates excellent compatibility and adaptability with the material system and preparation process of the reversible photochromic paper basin.

[0026] Preferably, the mass ratio of the first aqueous polymer matrix to the photochromic microcapsule is 100:(1.5-30), for example, it can be 100:2, 100:3, 100:5, 100:8, 100:10, 100:12, 100:15, 100:18, 100:20, 100:22, 100:25, 100:28, etc.

[0027] It should be noted that the mass ratio of the first aqueous polymer matrix to the photochromic microcapsule is calculated based on the mass of the aqueous solution or aqueous dispersion of the first aqueous polymer matrix.

[0028] Preferably, the first aqueous polymer matrix comprises any one or a combination of at least two of the following: aqueous polyurethane adhesive, aqueous polyacrylate adhesive, polyvinyl alcohol, and polyvinyl acetate.

[0029] As a preferred embodiment of the present invention, the first aqueous polymer matrix includes any one or a combination of at least two of aqueous polyurethane adhesive, aqueous polyacrylate adhesive, polyvinyl alcohol (PVA), and polyvinyl acetate (PVAc), which not only ensures the uniform dispersion of the photochromic microcapsules and the uniform color development of the photochromic layer, but also provides excellent modulus and waterproof performance.

[0030] Preferably, the photochromic layer further includes an anti-UV additive.

[0031] In this invention, the UV-resistant additive can be understood as an ultraviolet absorber. Adding it to the photochromic layer can improve the UV aging resistance of the photochromic layer and the reversible photochromic paper basin, making the color-changing effect more durable and stable.

[0032] Preferably, the UV-resistant additive is an organic UV-resistant additive, and more preferably includes any one or a combination of at least two of the following: salicylates, benzophenones, benzotriazoles, substituted acrylonitrile additives, triazines, and hindered amines.

[0033] In this invention, the UV-resistant additive can be purchased through commercial channels, such as commercially available ultraviolet absorber UV-1130.

[0034] Preferably, the mass ratio of the UV-resistant additive to the first aqueous polymer matrix is ​​(0.15-1.5):100, for example, it can be 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.8:100, 1:100, 1.2:100 or 1.4:100, etc.

[0035] It should be noted that the mass ratio of the UV-resistant additive to the first aqueous polymer matrix is ​​calculated based on the mass of the aqueous solution or dispersion of the first aqueous polymer matrix. A mass ratio of (0.15-1.5):100 for the UV-resistant additive to the first aqueous polymer matrix (its aqueous solution / dispersion) effectively enhances its UV aging resistance while ensuring a stable and sensitive color-changing effect. Excessive use of the UV-resistant additive will result in a lighter color and a poorer color-changing effect.

[0036] Preferably, the thickness of the photochromic layer is 25-50 μm, for example, it can be 26 μm, 28 μm, 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, 42 μm, 45 μm or 48 μm, and specific values ​​between the above values. For space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. Preferably, the photochromic layer is obtained by coating a photochromic coating onto an isolation layer and drying it; the photochromic coating comprises a combination of a first aqueous polymer matrix, photochromic microcapsules, and optionally, an anti-UV additive.

[0037] Preferably, the viscosity of the first aqueous polymer matrix is ​​≤1000 cps, for example, it can be 300 cps, 350 cps, 400 cps, 450 cps, 500 cps, 550 cps, 600 cps, 650 cps, 700 cps, 750 cps, 800 cps, 850 cps, 900 cps or 950 cps, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 500-1000 cps is further preferred.

[0038] Preferably, the viscosity of the waterborne polyurethane adhesive is 500-800 cps, for example, it can be 520 cps, 550 cps, 580 cps, 600 cps, 620 cps, 650 cps, 680 cps, 700 cps, 720 cps, 750 cps or 780 cps, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0039] As a preferred embodiment of the present invention, the first aqueous polymer matrix includes an aqueous polyurethane adhesive with a viscosity of 500-800 cps. On the one hand, it can disperse photochromic microcapsules, making the color development more uniform. On the other hand, it can significantly improve the waterproofness of the paper cone surface, while the modulus of the paper cone is enhanced, providing good sound quality. Moreover, the appropriate viscosity helps in the dispersion of photochromic microcapsules, the preparation of photochromic coatings, and subsequent coating treatments.

[0040] Preferably, the first aqueous polymer matrix is ​​mixed with photochromic microcapsules and optionally an anti-UV additive in the form of an aqueous solution or aqueous dispersion to obtain the photochromic coating.

[0041] For example, the first aqueous polymer matrix includes an aqueous polyurethane adhesive and / or an aqueous polyacrylate adhesive, which are commercially available in the form of an aqueous solution or an aqueous dispersion.

[0042] For example, the first aqueous polymer matrix comprises polyvinyl alcohol and / or polyvinyl acetate, which are commercially available and can be further dissolved and / or dispersed in water to form an aqueous solution.

[0043] Preferably, the solid content of the aqueous solution or aqueous dispersion is ≤50%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, or 48%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 20-30% is further preferred.

[0044] Preferably, the first aqueous polymer matrix comprises polyvinyl alcohol, and the solid content of the polyvinyl alcohol aqueous solution is 10-50%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, or 48%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 20-30% is further preferred.

[0045] Preferably, the first aqueous polymer matrix comprises polyvinyl acetate, and the solid content of the polyvinyl acetate aqueous solution is 10-50%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, or 48%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 20-30% is further preferred.

[0046] As a preferred technical solution of the present invention, by controlling the solid content of polyvinyl alcohol aqueous solution and polyvinyl acetate aqueous solution, the photochromic coating has a suitable viscosity, which facilitates the coating operation, while making the weight gain and density of the reversible photochromic paper basin small and having high sensitivity.

[0047] Preferably, the photochromic coating also includes a diluent.

[0048] Preferably, the diluent comprises water.

[0049] Preferably, the photochromic microcapsules in the photochromic coating have a mass percentage content of 1.5-20%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, or 18%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 2-15% is further preferred.

[0050] Preferably, the UV-resistant additive in the photochromic coating has a mass percentage content of 0.1-1.5%, for example, it can be 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2% or 1.4%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 0.2-1.2% is further preferred.

[0051] In this invention, the protective layer comprises a combination of a second aqueous polymer matrix and nano-titanium dioxide. The introduction of nano-titanium dioxide enhances the UV resistance of the reversible photochromic cone while maintaining excellent color-changing effects. Specifically, the nano-titanium dioxide effectively blocks ultraviolet light through physical action, thereby reducing UV penetration. Since the protective layer is located on the outer side, it preferentially receives light under illumination. The weakened ultraviolet light reaches the photochromic layer, causing it to change color. The nano-titanium dioxide provides stable UV resistance. Furthermore, the addition of nano-titanium dioxide increases the rigidity of the protective layer and the reversible photochromic cone, effectively reducing resonance and sound distortion, while also enhancing the durability of the cone surface and improving the stability and sound quality of the speaker.

[0052] Preferably, the photochromic layer comprises a combination of a first aqueous polymer matrix, photochromic microcapsules, and an anti-UV additive, and the protective layer comprises a combination of a second aqueous polymer matrix and nano-titanium dioxide. The combination of the anti-UV additive in the photochromic layer and the nano-titanium dioxide in the protective layer enhances the UV aging resistance of the entire reversible photochromic paper tray. Through the combination of layers and materials, the UV aging resistance of the paper tray can be improved in a relatively balanced manner while ensuring photochromism. The nano-titanium dioxide and the outer protective layer provide effective physical shielding, slowing down the degradation of the photochromic material in the photochromic microcapsules. The anti-UV additive (organic anti-UV additive) is distributed in the photochromic layer, enhancing the overall aging resistance of the photochromic layer and absorbing UV radiation of specific wavelengths through a chemical absorption mechanism, ensuring the uniformity and stability of the photochromic layer and providing more comprehensive UV protection.

[0053] Preferably, the second aqueous polymer matrix comprises an aqueous polyurethane adhesive.

[0054] Preferably, the viscosity of the second aqueous polymer matrix is ​​100-300 cps, for example, it can be 120 cps, 150 cps, 180 cps, 200 cps, 220 cps, 250 cps or 280 cps, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0055] As a preferred embodiment of the present invention, the second waterborne polymer matrix uses a waterborne polyurethane adhesive with a low viscosity of 100-300 cps, which can reduce the thickness of the protective layer and improve the modulus and water resistance of the reversible photochromic paper basin. The second waterborne polymer matrix, combined with nano-silica, can block ultraviolet radiation, improve the UV resistance of the reversible photochromic paper basin, and enhance the stability of the product.

[0056] Preferably, the particle size of the nano-titanium dioxide is 20-100nm, for example, it can be 30nm, 40nm, 50nm, 60nm, 70nm, 80nm or 90nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0057] Preferably, the mass ratio of the waterborne polyurethane adhesive to nano titanium dioxide is 100:(0.1-2), for example, it can be 100:0.2, 100:0.3, 100:0.5, 100:0.6, 100:0.8, 100:1, 100:1.2, 100:1.5, or 100:1.8, and more preferably 100:(0.5-1.5).

[0058] Preferably, the thickness of the protective layer is 10-30 μm, for example, it can be 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm or 28 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0059] Preferably, the paper basin substrate is a white or light-colored paper basin.

[0060] Preferably, the raw materials for preparing the paper basin substrate include the following components in parts by weight:

[0061]

[0062]

[0063] Specifically, in the raw materials for preparing the paper basin substrate, the wood pulp has a mass fraction of 50-70 parts, for example, 52 parts, 54 parts, 55 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 65 parts, 66 parts or 68 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0064] The mass fraction of the hemp pulp is 5-35 parts, for example, it can be 6 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts or 34 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but preferably 10-30 parts.

[0065] The mass fraction of the cotton pulp is 5-30 parts, for example, it can be 6 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts or 28 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but preferably 10-20 parts.

[0066] The mass fraction of the additive is 0-10 parts, for example, it can be 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0067] Preferably, the wood pulp comprises bleached sulfate wood pulp and / or unbleached sulfate wood pulp, and more preferably bleached sulfate wood pulp.

[0068] Preferably, the additives include any one or a combination of at least two of cationic styrene-acrylic emulsion, cationic starch, and emulsified paraffin, with cationic styrene-acrylic emulsion being more preferred.

[0069] As a preferred technical solution of the present invention, the reversible photochromic paper basin has sensitive photoresponsiveness and can develop color (e.g., appearing blue, purple, orange, red, orange, etc.) under sunlight or ultraviolet light, and fade (restore the original color) when the ultraviolet light is removed or in an indoor environment. Its fading time is ≤20min, preferably ≤10min, more preferably ≤6min, more preferably ≤5min, and can even reach 30-70s, for example, 40s, 50s, 60s, etc.

[0070] Preferably, the density of the reversible photochromic paper basin is ≤0.77 g / cm³. 3 For example, it can be 0.70 g / cm³. 3 0.71g / cm 3 0.72g / cm 3 0.73g / cm 3 0.74g / cm 3 0.75g / cm 3 Or 0.76g / cm 3 As well as the specific point values ​​between the above point values, due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0071] Preferably, the Young's modulus of the reversible photochromic paper basin is 1.9-3 GPa, for example, it can be 2 GPa, 2.2 GPa, 2.4 GPa, 2.5 GPa, 2.6 GPa, 2.8 GPa or 2.9 GPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0072] Preferably, the loss factor of the reversible photochromic paper basin is 0.025-0.06, for example, it can be 0.026, 0.028, 0.03, 0.032, 0.035, 0.038, 0.04, 0.042, 0.045, 0.048, 0.05, 0.052, 0.055 or 0.058, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0073] In a second aspect, the present invention provides a method for preparing a reversible photochromic paper basin as described in the first aspect, the method comprising: sequentially depositing an isolation layer, a photochromic layer and a protective layer on a paper basin substrate to obtain the reversible photochromic paper basin.

[0074] Preferably, the preparation method includes the following steps:

[0075] A release coating is applied to a paper basin substrate and dried to obtain a release layer; the release coating comprises a combination of polyvinyl alcohol, cationic guar gum and water.

[0076] A photochromic coating is coated onto the isolation layer, followed by a second drying process to obtain a photochromic layer; the photochromic coating comprises a combination of a first aqueous polymer matrix, photochromic microcapsules, and optionally, an anti-UV additive;

[0077] A protective coating is applied to the photochromic layer, followed by a third drying process to form a protective layer, thereby obtaining the reversible photochromic paper basin; the protective coating comprises a combination of a second water-based polymer matrix and nano-titanium dioxide.

[0078] Preferably, the preparation method of the paper basin substrate includes: mixing wood pulp, hemp pulp and cotton pulp according to the formula amount, beating and dispersing evenly, then adding optional additives and mixing evenly to obtain a fiber suspension; filtering and molding the fiber suspension, hot pressing and drying to obtain the paper basin substrate.

[0079] Preferably, the beating degree of the pulp is 15-30°SR, for example, it can be 18°SR, 20°SR, 22°SR, 25°SR or 28°SR, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0080] Preferably, the hot-press drying temperature is 150-200℃, for example, it can be 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃ or 195℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 160-180℃ is further preferred.

[0081] Preferably, the hot-press drying time is 20-90s, for example, it can be 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, 65s, 70s, 75s, 80s or 85s, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 30-60s is further preferred.

[0082] Preferably, the method for preparing the isolation coating includes: mixing polyvinyl alcohol aqueous solution and cationic guar gum aqueous solution evenly to obtain the isolation coating.

[0083] Preferably, the polyvinyl alcohol content in the aqueous solution is 5-10% by mass, for example, 6%, 7%, 8% or 9%, and specific values ​​between the above values ​​are not exhaustively listed here for space limitations and for the sake of brevity.

[0084] Preferably, the cationic guar gum aqueous solution contains 1-5% cationic guar gum by mass, for example, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0085] Preferably, the mass ratio of the polyvinyl alcohol aqueous solution to the cationic guar gum aqueous solution is (2-4):1, for example, it can be 2.2:1, 2.4:1, 2.5:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.5:1, 3.6:1 or 3.8:1, etc.

[0086] Preferably, the preparation method of the photochromic coating includes: mixing a first aqueous polymer matrix (its aqueous solution / aqueous dispersion) with photochromic microcapsules, an anti-UV additive, and optionally a diluent to obtain the photochromic coating.

[0087] More preferably, the preparation method of the photochromic coating includes: first mixing a first aqueous polymer matrix (its aqueous solution / aqueous dispersion) with photochromic microcapsules, and then second mixing it with an anti-UV additive and optionally a diluent to obtain the photochromic coating.

[0088] Preferably, the first mixing and the second mixing are carried out by a homogenizing centrifuge.

[0089] Preferably, the rotational speed of the first mixing is 500-1000 rpm, for example, it can be 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, 900 rpm or 950 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0090] Preferably, the first mixing time is 3-5 min, for example, it can be 3.2 min, 3.5 min, 3.8 min, 4 min, 4.2 min, 4.5 min or 4.8 min, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0091] Preferably, the rotational speed of the second mixing is 800-1200 rpm, for example, it can be 850 rpm, 900 rpm, 950 rpm, 1000 rpm, 1050 rpm, 1100 rpm or 1150 rpm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0092] Preferably, the second mixing time is 3-5 min, for example, it can be 3.2 min, 3.5 min, 3.8 min, 4 min, 4.2 min, 4.5 min or 4.8 min, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0093] Preferably, the method for preparing the protective coating includes: mixing and dispersing a second aqueous polymer matrix and nano-titanium dioxide evenly to obtain the protective coating.

[0094] Preferably, the dispersion is carried out by a homogenizing centrifuge.

[0095] Preferably, the methods for applying the isolation coating, the photochromic coating, and the protective coating each independently include spraying and / or spin coating.

[0096] Preferably, the spin coating speed is 200-3800 rpm, for example, it can be 300 rpm, 500 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1500 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2500 rpm, 2800 rpm, 3000 rpm, 3200 rpm or 3500 rpm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0097] Preferably, the temperatures for the first drying, the second drying, and the third drying are each independently 45-80°C, for example, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, or 78°C, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range, but 50-70°C is further preferred.

[0098] Preferably, the drying times for the first, second, and third drying processes are each independently 0.2-2 hours, for example, 0.3 hours, 0.5 hours, 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, or 1.8 hours, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range, but 0.5-1.5 hours is further preferred.

[0099] Thirdly, the present invention provides a loudspeaker comprising a reversible photochromic paper cone as described in the first aspect.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] (1) In the reversible photochromic paper basin provided by the present invention, an isolation layer, a photochromic layer and a protective layer are sequentially arranged on the paper basin substrate. Through the design of the layers and materials and their compounding effect, the rigidity and surface flatness of the paper basin are increased, the amount of photochromic coating is reduced, and the reversible photochromic paper basin has sensitive light-response color-changing characteristics. It has a fast color-changing response under ultraviolet light or sunlight, and fades quickly when the ultraviolet light is turned off or indoors. It can realize the application of a variety of different colors and diverse appearances to meet different needs.

[0102] (2) The reversible photochromic paper cone has uniform and stable color development and color change effects, high modulus, strength and rigidity, excellent mechanical properties, acoustic properties, sensitivity and sound quality, and excellent resistance to ultraviolet aging. The number of repeated color changes increases, and the effective time can be extended after continuous exposure. It can still achieve reversible color change after continuous UV aging for 36-48 hours. It has excellent applicability and can be used in some special scenarios for monitoring ultraviolet rays or outdoor use. Attached Figure Description

[0103] Figure 1 A schematic diagram of the structure of a reversible photochromic paper basin provided for a specific embodiment;

[0104] Among them, 1-paper basin substrate, 2-isolation layer, 3-photochromic layer, 4-protective layer. Detailed Implementation

[0105] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0106] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0107] "Optionally," "optionally," or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event occurs and the possibility that the event does not occur.

[0108] In this invention, features specified as "first" and "second" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0109] In one specific embodiment, a schematic diagram of the reversible photochromic paper basin is shown below. Figure 1 As shown, the device includes a paper basin substrate 1, an isolation layer 2, a photochromic layer 3, and a protective layer 4 arranged sequentially; the isolation layer 2 comprises a combination of polyvinyl alcohol and cationic guar gum; the photochromic layer 3 comprises a combination of a first aqueous polymer matrix and photochromic microcapsules; and the protective layer 4 comprises a combination of a second aqueous polymer matrix and nano-titanium dioxide.

[0110] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0111]

[0112]

[0113] The following will use several embodiments as examples to describe in detail the reversible photochromic paper basin and its preparation method according to the present invention, but the reversible photochromic paper basin and its preparation method according to the present invention are not limited to these embodiments.

[0114] Preparation Example

[0115] Preparation of paper basin substrate: Weigh 60 parts of bleached sulfate wood pulp, 30 parts of hemp pulp, and 10 parts of cotton pulp, mix and beat until the freeness is 20°SR, then add water to dilute and loosen. During loosening, add 5 parts of cationic styrene-acrylic emulsion, stir and disperse at 1000 rpm for 5 minutes to fully disperse and obtain a fiber suspension; adjust the fiber suspension concentration to 0.1%, filter and form on a paper machine, and then hot press at 180℃ for 40s to obtain a white paper basin substrate.

[0116] In the following specific embodiments of the present invention, the paper basin substrates are all white paper basin substrates prepared in the preparation examples.

[0117] Example 1

[0118] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0119] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 8wt%) and cationic guar gum aqueous solution (mass concentration of 2wt%) at a mass ratio of 7:2 to obtain the isolation coating;

[0120] Preparation of photochromic coating: By weight, 5 parts of purple photochromic microcapsules and 95 parts of waterborne polyurethane adhesive A are mixed and dispersed in a homogenizer at 800 rpm for 4 min. Then, 0.5 parts of UV-1130 are added and dispersed at 1000 rpm for 4 min to obtain the photochromic coating.

[0121] Preparation of protective coating: Mix 1 part by weight of nano titanium dioxide and 100 parts by weight of water-based polyurethane adhesive B evenly using a homogenizing centrifuge to obtain the protective coating.

[0122] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater, and then dried in a 60°C oven for 1 hour to obtain an isolation layer with a thickness of 15 μm; then the photochromic coating was spin-coated, and then dried at 60°C for 1 hour to obtain a photochromic layer with a thickness of 35 μm; then the protective coating was spin-coated, and dried at 60°C for 1 hour to obtain a protective layer with a thickness of 15 μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were as follows: the spin-coating speed of the first stage was 300 rpm, and the time was 3 s; the spin-coating speed of the second stage was 1500 rpm, and the time was 3 s; the spin-coating speed of the third stage was 3000 rpm, and the time was 3 s.

[0123] Example 2

[0124] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0125] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 5wt%) and cationic guar gum aqueous solution (mass concentration of 5wt%) at a mass ratio of 6:2 to obtain the isolation coating;

[0126] Preparation of photochromic coating: By weight, 5 parts of purple photochromic microcapsules and 95 parts of water-based polyacrylate adhesive A are mixed and dispersed in a homogenizer at 500 rpm for 5 min. Then, 0.5 parts of UV-1130 are added and dispersed at 800 rpm for 5 min to obtain the photochromic coating.

[0127] Preparation of protective coating: By weight, 0.2 parts of nano titanium dioxide and 100 parts of water-based polyurethane adhesive B are mixed evenly using a homogenizing centrifuge to obtain the protective coating.

[0128] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater, and then dried in a 70℃ oven for 0.5h to obtain an isolation layer with a thickness of 20μm; then the photochromic coating was spin-coated, and then dried in a 70℃ oven for 0.5h to obtain a photochromic layer with a thickness of 40μm; then the protective coating was spin-coated, and dried in a 70℃ oven for 0.5h to obtain a protective layer with a thickness of 10μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were: the spin-coating speed of the first stage was 500rpm, and the time was 3s; the spin-coating speed of the second stage was 1200rpm, and the time was 4s; the spin-coating speed of the third stage was 3500rpm, and the time was 3s.

[0129] Example 3

[0130] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0131] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 5wt%) and cationic guar gum aqueous solution (mass concentration of 1wt%) at a mass ratio of 8:3 to obtain the isolation coating;

[0132] Preparation of photochromic coating: By weight, 20 parts of purple photochromic microcapsules were mixed with 80 parts of PVA aqueous solution (solid content of 30%), dispersed in a homogenizer at 1000 rpm for 3 min, then 1 part of UV-1130 was added, and then dispersed at 1200 rpm for 3 min to obtain the photochromic coating.

[0133] Preparation of protective coating: By weight, 1.5 parts of nano titanium dioxide and 100 parts of water-based polyurethane adhesive B are mixed evenly using a homogenizing centrifuge to obtain the protective coating.

[0134] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater, and then dried in a 50°C oven for 1.5 hours to obtain an isolation layer with a thickness of 5 μm; then the photochromic coating was spin-coated, and then dried in a 50°C oven for 1.5 hours to obtain a photochromic layer with a thickness of 42 μm; then the protective coating was spin-coated, and dried in a 50°C oven for 1.5 hours to obtain a protective layer with a thickness of 25 μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were as follows: the spin-coating speed of the first stage was 400 rpm, and the time was 4 s; the spin-coating speed of the second stage was 1400 rpm, and the time was 3 s; the spin-coating speed of the third stage was 3200 rpm, and the time was 4 s.

[0135] Example 4

[0136] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0137] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 8wt%) and cationic guar gum aqueous solution (mass concentration of 2wt%) at a mass ratio of 7:2 to obtain the isolation coating;

[0138] Preparation of photochromic coating: By weight, 2 parts of purple photochromic microcapsules were mixed with 98 parts of PVAc aqueous solution (solid content of 30%), dispersed in a homogenizer at 800 rpm for 4 min, then 0.2 parts of UV-1130 were added, and then dispersed at 1000 rpm for 4 min to obtain the photochromic coating.

[0139] Preparation of protective coating: Mix 1 part by weight of nano titanium dioxide and 100 parts by weight of water-based polyurethane adhesive B evenly using a homogenizing centrifuge to obtain the protective coating.

[0140] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater, and then dried in a 60℃ oven for 1 hour to obtain an isolation layer with a thickness of 10μm; then the photochromic coating was spin-coated, and then dried at 60℃ for 1 hour to obtain a photochromic layer with a thickness of 25μm; then the protective coating was spin-coated, and dried at 60℃ for 1 hour to obtain a protective layer with a thickness of 15μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were as follows: the spin-coating speed of the first stage was 300rpm, and the time was 3s; the spin-coating speed of the second stage was 1500rpm, and the time was 3s; the spin-coating speed of the third stage was 3000rpm, and the time was 3s.

[0141] Example 5

[0142] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0143] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 10wt%) and cationic guar gum aqueous solution (mass concentration of 1wt%) at a mass ratio of 4:1 to obtain the isolation coating;

[0144] Preparation of photochromic coating: By weight, 20 parts of purple photochromic microcapsules were mixed with 80 parts of PVA aqueous solution (solid content of 10%), dispersed in a homogenizer at 1000 rpm for 3 min, then 1 part of UV-1130 was added, and then dispersed at 1200 rpm for 3 min to obtain the photochromic coating.

[0145] Preparation of protective coating: Mix 0.5 parts by weight of nano titanium dioxide and 100 parts by weight of water-based polyurethane adhesive B evenly using a homogenizing centrifuge to obtain the protective coating.

[0146] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater to obtain an isolation layer with a thickness of 15 μm; then the photochromic coating was spin-coated, and then dried in an oven at 50℃ for 1.5 h to obtain a photochromic layer with a thickness of 30 μm; then the protective coating was spin-coated, and dried in an oven at 50℃ for 1.5 h to obtain a protective layer with a thickness of 12 μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were as follows: the spin-coating speed of the first stage was 400 rpm, and the time was 4 s; the spin-coating speed of the second stage was 1400 rpm, and the time was 3 s; the spin-coating speed of the third stage was 3200 rpm, and the time was 4 s.

[0147] Example 6

[0148] A reversible photochromic paper basin includes a paper basin substrate, an insulating layer, a photochromic layer, and a protective layer arranged sequentially; the preparation method is as follows:

[0149] (1) Preparation of the isolation coating: Mix polyvinyl alcohol aqueous solution (PVA mass concentration of 10wt%) and cationic guar gum aqueous solution (mass concentration of 1wt%) at a mass ratio of 2:1 to obtain the isolation coating;

[0150] Preparation of photochromic coating: By weight, 20 parts of purple photochromic microcapsules were mixed with 80 parts of PVA aqueous solution (solid content of 50%), dispersed in a homogenizer at 1000 rpm for 3 min, then 1 part of UV-1130 was added, and then dispersed at 1200 rpm for 3 min to obtain the photochromic coating.

[0151] Preparation of protective coating: By weight, mix 2 parts of nano titanium dioxide and 100 parts of water-based polyurethane adhesive B evenly using a homogenizing centrifuge to obtain the protective coating.

[0152] (2) The isolation coating was spin-coated onto the paper basin substrate using a spin coater, and then dried in a 50°C oven for 1.5 hours to obtain an isolation layer with a thickness of 18 μm; then the photochromic coating was spin-coated, and then dried in a 50°C oven for 1.5 hours to obtain a photochromic layer with a thickness of 50 μm; then the protective coating was spin-coated, and dried in a 50°C oven for 1.5 hours to obtain a protective layer with a thickness of 30 μm, thus completing the preparation of the reversible photochromic paper basin; wherein, the isolation coating, photochromic coating and protective coating were all spin-coated in 3 stages, and the spin-coating parameters were as follows: the spin-coating speed of the first stage was 400 rpm, and the time was 4 s; the spin-coating speed of the second stage was 1400 rpm, and the time was 3 s; the spin-coating speed of the third stage was 3200 rpm, and the time was 4 s.

[0153] Example 7

[0154] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the purple photochromic microcapsules are replaced with orange photochromic microcapsules of equal mass. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0155] Example 8

[0156] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the purple photochromic microcapsules are replaced with an equal mass of blue photochromic microcapsules. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0157] Example 9

[0158] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the purple photochromic microcapsules are replaced with red photochromic microcapsules of equal mass. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0159] Example 10

[0160] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that UV-1130 is not added to the photochromic coating. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0161] Comparative Example 1

[0162] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the purple photochromic microcapsules are replaced with an equal mass of purple photochromic powder. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0163] Comparative Example 2

[0164] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the waterborne polyurethane adhesive A in the photochromic coating is replaced with a waterborne polyacrylate adhesive B with a viscosity of 100 cps. All other materials, dosages, and process parameters are the same as in Example 1, thus obtaining the reversible photochromic paper basin.

[0165] Comparative Example 3

[0166] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the water-based polyurethane adhesive A in the photochromic coating is replaced with an equal mass of paraffin emulsion. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0167] Comparative Example 4

[0168] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that the cationic guar gum in the isolation coating is replaced with an equal mass of PVA. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0169] Comparative Example 5

[0170] A reversible photochromic paper basin differs from Example 1 only in that it does not have an isolation layer. Instead, a photochromic layer and a protective layer are sequentially formed on the paper basin substrate. The materials and preparation methods of the photochromic layer and the protective layer are the same as those in Example 1.

[0171] Comparative Example 6

[0172] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that nano-titanium dioxide is not added to the protective coating. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0173] Comparative Example 7

[0174] A reversible photochromic paper basin differs from Example 1 only in that it does not have a protective layer. Instead, an isolation layer and a photochromic layer are sequentially formed on the paper basin substrate. The materials and preparation methods of the isolation layer and the photochromic layer are the same as those in Example 1.

[0175] Comparative Example 8

[0176] A reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The only difference between this and Example 1 is that nano-titanium dioxide from the protective coating is added to the color-changing coating. All other materials, dosages, and process parameters are the same as in Example 1, resulting in the reversible photochromic paper basin.

[0177] The following performance tests were conducted on the reversible photochromic paper basins provided in Examples 1-10 and Comparative Examples 1-8:

[0178] (1) Density: The mass of the sample to be tested was measured by an analytical balance, and the thickness of the sample to be tested was measured by a thickness gauge. The thickness of the same sample was measured three times and the average value was taken to calculate the sample density.

[0179] (2) Weight gain: The degree of increase in the mass of the reversible photochromic paper basin relative to the mass of the paper basin substrate of the preparation example. The mass of the reversible photochromic paper basin is m, and the mass of the paper basin substrate of the preparation example is m0. Weight gain (%) = 100% × (m - m0) / m0.

[0180] (3) Young's modulus and loss factor: The Young's modulus of the sample was tested by the bending modulus method, and the Young's modulus and loss factor were measured by the MPM material parameter module in the KLIPPEL testing system.

[0181] (4) Dispersion and color development: Before applying the protective coating, place the sample under sunlight and observe the color development on the surface of the paper basin. Visually observe whether the color is uniform and whether there are particles on the surface. A smooth paper basin surface without particles is marked as "good dispersion". Fewer than 5 particles on the surface of the paper basin is marked as "good dispersion". More than 10 particles on the surface are marked as "poor dispersion". Uniform and continuous color development is marked as "uniform color development". Uneven and discontinuous color development is marked as "poor color development".

[0182] After applying a protective coating to the paper tray with uniform display, a UV aging test was conducted under the following conditions: UV-a, 340nm, 0.89W / m 2 / nm, continuously irradiated at 60℃±3℃, and its reversible color change performance was examined every 2 hours. If the reversible color change performance disappeared, it was marked as "failed".

[0183] (5) Fading time: Place the reversible photochromic paper basin under sunlight to make it change color, then move it indoors and count the fading time.

[0184] The test results are shown in Table 1:

[0185] Table 1

[0186]

[0187]

[0188] As shown in Table 1, the test data of this invention, by sequentially setting an isolation layer, a photochromic layer, and a protective layer on the paper basin substrate, and through the design of the layers and materials and their compounding effect, enables the reversible photochromic paper basin to have sensitive light-responsive color-changing characteristics. The color-changing response under light is fast, and it can fade quickly indoors, recovering its original color in as little as 30 seconds. Simultaneously, the photochromic microcapsules in the photochromic layer are uniformly dispersed, making the color development and color-changing effects of the reversible photochromic paper basin uniform and stable, with a modulus of 1.92-2.98 GPa, a loss factor of 0.028-0.058, and a density of 0.709-0.763 g / cm³. 3 It possesses excellent mechanical properties, acoustic properties, sensitivity, and sound quality; moreover, it exhibits excellent resistance to ultraviolet aging, and can still achieve reversible color change after continuous UV irradiation for 36-48 hours, demonstrating good applicability.

[0189] This invention preferably uses waterborne polyurethane adhesive, waterborne polyacrylate adhesive, PVA, and PVAc as the first waterborne polymer matrix as the dispersion system for photochromic microcapsules, all of which can achieve uniform dispersion and color development. Specifically, in Example 1, when using waterborne polyurethane adhesive, the weight gain was 6.02%, the modulus of the paper cone was significantly improved, and the paper cone exhibited excellent waterproof performance. In Example 2, when using waterborne polyacrylate adhesive, the weight gain was relatively large, at 13.6%, while the modulus decreased somewhat. Examples 3, 5, and 6 used PVA with solid contents of 30%, 10%, and 50%, respectively. At low solid contents, the weight gain in Examples 3 and 5 was minimal, at 4.56% and 3.85%, respectively, and the resulting paper cones exhibited high sensitivity. When using PVA with high solid contents, the solution viscosity increased, which was detrimental to operability, and the weight gain was significant; the modulus decreased to some extent when using PVA. In Example 4, when using PVAc, the weight gain of the paper cone was moderate, but the modulus of the paper cone decreased somewhat.

[0190] As can be seen from Examples 1 and 7-9, the fading time and failure time after UV aging vary depending on the color of the photochromic microcapsule. This is mainly because the material composition of the photochromic microcapsule varies with the color. Therefore, the compositional differences of the photochromic microcapsule (especially the reversible photochromic material) have a significant impact on the color-changing effect and fading performance of the reversible photochromic paper basin. When purple photochromic microcapsules are selected, the fading time is the shortest.

[0191] The present invention preferably adds an anti-UV additive to the photochromic layer, which can further improve the UV resistance of the reversible photochromic paper basin and extend the effective time after UV aging. In Example 10, the photochromic layer does not use an anti-UV additive, but it can still disperse and develop color well, but its exposure time is shortened.

[0192] In Comparative Example 1, a reversible photochromic material was directly added to the photochromic layer and dispersed directly in an aqueous polymer matrix system. After coating and color development, the paper basin surface showed obvious particle protrusions, and the color development was discontinuous and could not be uniformly covered. Comparative Example 2, using a low-viscosity aqueous polyacrylate adhesive B as the dispersion system, showed similar results to Comparative Example 1: poor dispersibility, particles, and poor color development. Comparative Example 3 used an oily paraffin emulsion as the dispersion system. The paper basin surface had scattered particles, poor dispersibility, discontinuous color development, and weak adhesion to the paper basin, making it easy to detach by scratching. Comparative Example 4 had only polyvinyl alcohol as the isolation layer, while Comparative Example 5 had no isolation layer, resulting in a significant decrease in the modulus of the paper basin and an increased weight gain. This indicates that the isolation layer can reduce the penetration of the photochromic layer. Since polyvinyl alcohol and cationic guar gum can interact and affect the rigidity of the paper basin, the isolation layer of this invention uses a blend of both to obtain a lightweight paper basin product with high modulus. In Comparative Example 6, the absence of nano-titanium dioxide in the protective layer resulted in a decrease in the paper cone's modulus and a significant decline in its aging resistance. In Comparative Example 7, the absence of a protective layer led to a significant decrease in the paper cone's modulus and a severe reduction in its aging resistance. In Comparative Example 8, the addition of nano-titanium dioxide to the color-changing layer prevented the uniform application of surface isolation, thus affecting the paper cone's aging resistance.

[0193] The applicant declares that this invention illustrates the reversible photochromic paper basin, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A reversible photochromic paper basin, characterized in that, The reversible photochromic paper basin includes a paper basin substrate, an isolation layer, a photochromic layer, and a protective layer arranged sequentially. The insulating layer comprises a combination of polyvinyl alcohol and cationic guar gum; The photochromic layer comprises a combination of a first aqueous polymer matrix and photochromic microcapsules; The protective layer comprises a combination of a second aqueous polymer matrix and nano-titanium dioxide.

2. The reversible photochromic paper basin according to claim 1, characterized in that, The mass ratio of polyvinyl alcohol to cationic guar gum in the isolation layer is (2-40):1, preferably (5-30):1; Preferably, the thickness of the isolation layer is 5-20 μm.

3. The reversible photochromic paper basin according to claim 1 or 2, characterized in that, The isolation layer is obtained by coating an isolation coating onto a paper basin substrate and drying it. The isolation coating comprises a combination of an aqueous solution of polyvinyl alcohol and an aqueous solution of cationic guar gum. Preferably, the polyvinyl alcohol in the aqueous solution contains 5-10% polyvinyl alcohol by mass. Preferably, the cationic guar gum aqueous solution contains 1-5% cationic guar gum by mass. Preferably, the mass ratio of the polyvinyl alcohol aqueous solution to the cationic guar gum aqueous solution is (2-4):

1.

4. The reversible photochromic paper basin according to any one of claims 1-3, characterized in that, The first aqueous polymer matrix includes any one or a combination of at least two of the following: aqueous polyurethane adhesive, aqueous polyacrylate adhesive, polyvinyl alcohol, and polyvinyl acetate; Preferably, the photochromic layer further includes an anti-UV additive; Preferably, the mass ratio of the UV-resistant additive to the first aqueous polymer matrix is ​​(0.15-1.5):100; Preferably, the thickness of the photochromic layer is 25-50 μm.

5. The reversible photochromic paper basin according to any one of claims 1-4, characterized in that, The photochromic layer is obtained by coating a photochromic coating onto an isolation layer and drying it; the photochromic coating comprises a combination of a first aqueous polymer matrix, photochromic microcapsules, and optionally anti-UV additives; Preferably, the photochromic microcapsules in the photochromic coating contain 1.5-20% by mass. Preferably, the UV-resistant additive in the photochromic coating has a mass percentage content of 0.1-1.5%.

6. The reversible photochromic paper basin according to any one of claims 1-5, characterized in that, The second waterborne polymer matrix includes a waterborne polyurethane adhesive; Preferably, the viscosity of the second aqueous polymer matrix is ​​100-300 cps; Preferably, the particle size of the nano-titanium dioxide is 20-100 nm; Preferably, the mass ratio of the waterborne polyurethane adhesive to nano-titanium dioxide is 100:(0.1-2), more preferably 100:(0.5-1.5); Preferably, the thickness of the protective layer is 10-30 μm.

7. The reversible photochromic paper basin according to any one of claims 1-6, characterized in that, The raw materials for preparing the paper basin substrate include the following components in parts by weight: Preferably, the wood pulp comprises bleached sulfate wood pulp and / or unbleached sulfate wood pulp, more preferably bleached sulfate wood pulp; Preferably, the additives include any one or a combination of at least two of cationic styrene-acrylic emulsion, cationic starch, and emulsified paraffin.

8. A method for preparing a reversible photochromic paper basin as described in any one of claims 1-7, characterized in that, The preparation method includes: sequentially depositing an isolation layer, a photochromic layer, and a protective layer on a paper basin substrate to obtain the reversible photochromic paper basin; Preferably, the preparation method includes the following steps: A release coating is applied to a paper basin substrate and dried to obtain a release layer; the release coating comprises a combination of polyvinyl alcohol, cationic guar gum and water. A photochromic coating is coated onto the isolation layer, followed by a second drying process to obtain a photochromic layer; the photochromic coating comprises a combination of a first aqueous polymer matrix, photochromic microcapsules, and optionally, an anti-UV additive; A protective coating is applied to the photochromic layer, followed by a third drying process to form a protective layer, thereby obtaining the reversible photochromic paper basin; the protective coating comprises a combination of a second water-based polymer matrix and nano-titanium dioxide.

9. The preparation method according to claim 8, characterized in that, The methods for applying the isolation coating, the photochromic coating, and the protective coating each independently include spraying and / or spin coating; Preferably, the temperatures for the first drying, the second drying, and the third drying are each independently 45-80°C, and more preferably 50-70°C; Preferably, the drying times for the first drying, the second drying, and the third drying are each 0.2-2 hours, and more preferably 0.5-1.5 hours.

10. A loudspeaker, characterized in that, The speaker comprises a reversible photochromic paper cone as described in any one of claims 1-7.

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