Reversible thermosensitive polymer functional dye and preparation method thereof

Abstract

The invention discloses a reversible thermosensitive polymer functional dye and a preparation method thereof, and belongs to the technical field of thermosensitive color-changing dyes, the reversible thermosensitive polymer functional dye comprises a color-changing core material and a transparent microcapsule, and the transparent microcapsule coats the color-changing core material. The color-changing core material is prepared from the following components: 8 to 12 parts of color-changing dye ODB, 15 to 28 parts of a color developing agent BFPA, 210 to 400 parts of a solvent benzyl phenyl ether, 6 to 15 parts of an antioxidant, 125 to 220 parts of montmorillonite subjected to surface treatment by an organosilane modified organic cationic surfactant, 56 to 82 parts of a nonionic polymer suspending aid and 5 to 12 parts of an ultraviolet light absorber; the capsule wall of the transparent microcapsule is prepared from a transparent polymer. The reversible thermosensitive polymer functional dye can improve the acting force of a color developing agent BFPA and a solvent benzyl phenyl ether, so that a complex of BFPA and thermosensitive black ODB is separated as soon as possible, and the color contrast of the reversible thermosensitive polymer functional dye in two states of color development and decoloration is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermochromic dyes, and particularly to a reversible thermosensitive polymer functional dye and a preparation method thereof. Background Art

[0002] Thermosensitive polymer functional dyes are a type of functional materials that can change color with temperature changes, and are widely used in fields such as anti-counterfeiting printing, intelligent temperature-sensitive glass, and thermosensitive paper production. The color change mechanism of thermochromic materials involves the reaction between leuco dyes and color developers, and the reaction between solvents and color developers. At low temperatures, the reaction between dyes and color developers is dominant, and the solvent is in a solid state, and the complex is colored at this time; at higher temperatures, the solvent melts, and the interaction between the solvent and the color developer dominates, and the complex turns into a colorless state. The interaction between the color developer and the solvent has a great influence on the color contrast and decolorization rate of the complex, so the selection of the solvent is crucial. At the same time, the use of microencapsulation technology to coat organic reversible thermochromic materials can improve their stability and protect the core material from the influence of the environment. The main problems existing in organic thermochromic materials are: the color contrast between the colored and decolored states is very poor, the color change sensitivity is low, and the environmental stability is poor.

[0003] The selection of the solvent is crucial for the performance of thermochromic complexes. Different solvents have different functional groups, and the strength of the interaction with the color developer is also different, which directly affects the color change sensitivity and contrast of the complex. For example, among the three solvents of phenyl benzoate, benzophenone, and benzyl phenyl ether, when phenyl benzoate is used as the solvent, the interaction force with the color developer is relatively strong, so the color change sensitivity of the complex is high and the contrast is large; the binding force between benzyl phenyl ether and the color developer BFPA is relatively weak, and the separation of BFPA from thermosensitive black ODB is not complete, resulting in a darker color of the system and a lower contrast. Among them, the largest contrast is phenyl benzoate benzophenone, the contrast of benzophenone is slightly lower than that of phenyl benzoate, the contrast of benzyl phenyl ether is the smallest, the color change temperature of the benzophenone complex is 45.8 - 47.5 °C, the color change temperature of the phenyl benzoate complex is 64.5 - 69.2 °C, and the color change temperature of benzyl phenyl ether is 36.8 - 39.8 °C. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a reversible thermosensitive polymer functional dye, which can improve the interaction force between the color developer BFPA and the solvent benzyl phenyl ether, separate the complex of BFPA and thermosensitive black ODB as soon as possible, and improve the color contrast between the colored and decolored states of the reversible thermosensitive polymer functional dye.

[0005] The second purpose of the present invention is to provide a manufacturing method of the reversible thermosensitive polymer functional dye, and the method has simple steps and low cost.

[0006] One of the objectives of the present invention is achieved by the following technical solution:

[0007] The reversible thermosensitive polymer functional dye includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8 - 12 parts of color-changing dye ODB, 15 - 28 parts of developer BFPA, 210 - 400 parts of solvent benzyl phenyl ether, 6 - 15 parts of antioxidant, 125 - 220 parts of montmorillonite surface-treated with an organosilane-modified organic cationic surfactant, 56 - 82 parts of organic cationic surfactant, 56 - 82 parts of non-ionic polymer suspending agent, and 5 - 12 parts of ultraviolet absorber; the capsule wall of the transparent microcapsules is made of a transparent polymer, and the transparent polymer is one of polytetrafluoroethylene, polytetrafluoroethylene propylene, and polysulfone.

[0008] Further, the color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant, 160 parts of montmorillonite surface-treated with an organosilane-modified organic cationic surfactant, 65 parts of non-ionic polymer suspending agent, and 8 parts of ultraviolet absorber.

[0009] Further, the ultraviolet absorber is 2,4-dihydroxybenzophenone, UV-326, and UV-531, which can further improve the light aging resistance of the material.

[0010] Further, the non-ionic polymer suspending agent is one or a mixture of PEG4000, PEG6000, and xanthan gum.

[0011] Further, the weight ratio of the thermosensitive black ODB: the developer BFPA: the solvent benzyl phenyl ether is 1:2:30.

[0012] Further, the organic cationic surfactant is one or two of di(hydrogenated tallow-based) benzyl methyl ammonium chloride (DHT) and dimethyldiallyl ammonium chloride.

[0013] Further, the antioxidant is one or two of 2,6-di-tert-butyl-p-cresol and 1010.

[0014] Further, the organosilane is one of 3-aminopropyltriethoxysilane (APS), γ-(methacryloxy)propyltrimethoxysilane (KH570), trimethylchlorosilane, and trimethylmethoxysilane.

[0015] Furthermore, the preparation method of the montmorillonite surface-treated with the organosilane-modified organic cationic surfactant comprises the following steps:

[0016] S1. Ultrasonic dispersion and decanter centrifuge classification: The montmorillonite suspension is subjected to ultrasonic dispersion and decanter centrifuge classification to separate the light phase and the heavy phase, and the montmorillonite particles in the light phase are smaller;

[0017] S2. The montmorillonite in the light phase is filtered through a sieve with a pore size less than 5 microns and centrifuged, and then spray-dried to obtain montmorillonite powder;

[0018] S3. The montmorillonite powder is washed with deionized water, centrifuged at 3500 rpm for 60 s after washing, and the supernatant is poured out, and then repeatedly washed with deionized water until the pH value is 5-6 to obtain the washed montmorillonite powder;

[0019] S4. After the final washing, 40 ml of the organic cationic surfactant is added to the ethanol aqueous solution at a volume ratio of 1:1, and then added to the washed montmorillonite powder, and mixed at room temperature for 12 hours. After mixing, vacuum filtration is carried out through a polypropylene membrane (Celgard LLC), and after filtration, it is dried in vacuo at 100 °C for 12 hours to obtain the montmorillonite surface-modified with the organic cationic surfactant;

[0020] S5. The organosilane is added to the solvent benzyl phenyl ether and dispersed evenly, and then the montmorillonite surface-modified with the organic cationic surfactant is added. Under the temperature condition above the boiling point of the organosilane and the reaction time is 48 h - 72 h, after the reaction, the solvent benzyl phenyl ether is evaporated to obtain the montmorillonite surface-treated with the organosilane-modified organic cationic surfactant.

[0021] The second object of the present invention is achieved by the following technical solution:

[0022] A preparation method of a reversible thermosensitive polymer functional dye, comprising the following steps:

[0023] S1. Weigh each component of the color-changing core material according to the formula amount and mix them evenly to obtain the color-changing core material;

[0024] S2. Using the color-changing core material as the core material, a catalyst and a monomer of the transparent polymer are added to the core material and stirred and mixed evenly;

[0025] S3. A water-soluble emulsifier is added to deionized water and mixed into the solution in step S2, and it is fully emulsified and dispersed by stirring. The transparent microcapsules are prepared by the in-situ polymerization method, and after spray-drying, it is the reversible thermosensitive polymer functional dye.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The reversible thermosensitive polymer functional dye provided by the present invention uses an organic reversible thermochromic material with thermosensitive black ODB, developer BFPA, and benzyl phenyl ether as the color-changing system. Both thermosensitive black ODB and developer BFPA are soluble in the solvent benzyl phenyl ether. Since the color-changing temperature of the thermochromic material is determined by the melting point of the solvent, when the melting point of the selected solvent is different, the color-changing temperature of the system will also change accordingly. The color-changing temperature of the benzophenone complex is 45.8 - 47.5 °C, the color-changing temperature of the phenyl benzoate complex is 64.5 - 69.2 °C, and the color-changing temperature of benzyl phenyl ether is 36.8 - 39.8 °C. By selecting benzyl phenyl ether as the solvent, the obtained reversible thermosensitive polymer functional dye can be used in textiles to reflect the body temperature. If there is a high fever, the color will fade significantly; by adding antioxidants and ultraviolet absorbers, the durability of the reversible thermosensitive polymer functional dye can be improved to avoid the degradation of the reversible thermosensitive polymer functional dye over time when exposed to ultraviolet light and repeated temperature cycles; montmorillonite adsorbs developer BFPA, reducing the free concentration of developer BFPA in the solution. This reduced free concentration indirectly affects the complexation between developer BFPA and thermosensitive black ODB because a certain concentration of free developer BFPA molecules is required for the complexation reaction to proceed; montmorillonite surface-modified with an organic cationic surfactant can replace the cations between the organic interlayers of montmorillonite. After modification, the surface negative charge of montmorillonite increases, making it easy to disperse in non-polar solvents. In the grafting reaction, the amino group of the organosilane forms a covalent bond with the silanol (Si-OH) and alcol (Al-OH) on the surface of montmorillonite, improving the unstable disadvantage of the organic intercalation of montmorillonite in non-polar solvents, increasing the affinity between montmorillonite and non-polar solvents, enhancing its dispersibility in non-polar solvents, not prone to flocculation, and strengthening the adsorption of developer BFPA by montmorillonite; the non-ionic polymer suspending agent increases the viscosity of the solvent benzyl phenyl ether, reducing the sedimentation rate of the montmorillonite fine powder, thus helping to maintain the uniform dispersion state of the montmorillonite fine powder particles in the solvent benzyl phenyl ether. Therefore, adding montmorillonite surface-treated with an organosilane-modified organic cationic surfactant and a non-ionic polymer suspending agent can improve the interaction between developer BFPA and the solvent benzyl phenyl ether, quickly separate the complex of BFPA and thermosensitive black ODB, and improve the color contrast and color-changing sensitivity of the reversible thermosensitive polymer functional dye in both the colored and decolored states. Urea: The reason why urea is used as a hydrogen bond disruptor is that it itself acts as both a strong hydrogen bond acceptor and donor, competing for the hydrogen bond sites on BFPA and breaking the hydrogen bonds of the complex of BFPA and thermosensitive black ODB, promoting the separation of BFPA and thermosensitive black ODB; the wall of the transparent microcapsule is prepared from a transparent polymer, and the transparent polymer is one of polytetrafluoroethylene, polytetrafluoroethylene propylene, and polysulfone, avoiding the interference of the color of the microcapsule itself on the observation of the color of the color-changing system and improving the color contrast of the reversible thermosensitive polymer functional dye in both the colored and decolored states. Detailed implementation manners

[0028] The following describes the present invention in further detail with reference to specific embodiments. It should be noted that, on the premise of no conflict, the following described embodiments or technical features can be combined arbitrarily to form new embodiments.

[0029] Bis(hydrogenated tallow) benzyl methyl ammonium chloride, English name: Dihydrogenated Tallow Benzylmonium Chloride, CAS No.: 61789-73-9; Melting point: The melting point of bis(hydrogenated tallow) benzyl methyl ammonium chloride is 140-148 °C, Freezing point: The freezing point of bis(hydrogenated tallow) benzyl methyl ammonium chloride is 64-72 °C. Bis(hydrogenated tallow) benzyl methyl ammonium chloride belongs to quaternary ammonium salt cationic surfactants. Its structure contains a benzyl group (benzyl) and a methyl group, and both of these groups are connected to a quaternary ammonium nitrogen atom. There are also two hydrogenated tallow groups (hydrogenated tallow alkyl) chains connected to the quaternary ammonium nitrogen atom. Since the hydrogenated tallow group is a long-chain alkyl group, this compound has two long-chain alkyl groups and a benzyl group, making it hydrophobic in structure. This structure enables bis(hydrogenated tallow) benzyl methyl ammonium chloride to have good dispersibility in non-polar solvents.

[0030] Diallyldimethylammonium chloride, English name: Diallyldimethylammonium Chloride (DADMAC), CAS No.: 61789-73-9, Melting point: 140 °C, Freezing point: about -2.8 °C.

[0031] Urea is solid at room temperature. The melting point and freezing point of urea are approximately 132-135 °C, which means that at normal room temperature (about 20-25 °C), urea is in a solid state. Only when the temperature rises above its melting point will urea turn into a liquid state.

[0032] UV-326 is a benzotriazole light stabilizer, and its chemical name is 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

[0033] UV-531 belongs to benzophenone ultraviolet absorbers, and its chemical name is 2-hydroxy-4-n-octyloxybenzophenone.

[0034] Montmorillonite is a layered hydrous aluminosilicate mineral, and its main component is montmorillonite. Its crystal is composed of two silicon-oxygen tetrahedrons sandwiching an aluminum-oxygen octahedron. In the layered structure formed by montmorillonite unit cells, there are a large number of metal cations filled. The interaction between these cations and montmorillonite unit cells is very unstable and is easily exchanged by other low-valence cations. After the exchange, the crystal layers carry a permanent negative charge.

[0035] Example 1

[0036] The reversible thermosensitive polymer functional dye provided in this example includes a color-changing core material and transparent microcapsules. The transparent microcapsules coat the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with an aminopropyltriethoxysilane-modified bis(hydrogenated tallow-based) benzylmethylammonium chloride cationic surfactant, 65 parts of non-ionic polymer suspending agent PEG4000, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is made of a polytetrafluoroethylene transparent polymer.

[0037] Among them, the weight ratio of thermosensitive black ODB: developer BFPA: solvent benzyl phenyl ether is 1:2:30.

[0038] Among them, the organic cationic surfactant is one or two of bis(hydrogenated tallow-based) benzylmethylammonium chloride (DHT) and dimethyldiallylammonium chloride.

[0039] 1010: This is a macromolecular multifunctional hindered phenol antioxidant, which is pollution-free, non-coloring, has low volatility, and good extraction resistance.

[0040] 2,6-Di-tert-butyl-p-cresol (BHT): 2,6-Di-tert-butyl-p-cresol is a colorless crystal or white crystalline powder, odorless and tasteless.

[0041] Polytetrafluoroethylene (PFA): It is a semi-transparent material. The melting point of PFA usually ranges between 260°C and 310°C. It is a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. It has good chemical resistance, can withstand strong acids and alkalis, and has a low blank value of metal elements.

[0042] Fluorinated ethylene propylene (FEP): It is fully transparent, and its melting point is generally between 208°C and 215°C. It is copolymerized from tetrafluoroethylene (TFE) and hexafluoropropylene (HFP). It can also withstand strong acids and alkalis, and has a low background.

[0043] Polysulfone (PSU): Polysulfone is an amber transparent solid material, with high hardness and impact strength, good heat and cold resistance and aging resistance. Its melting point is usually between 290°C and 310°C. It is prepared by polycondensation of bisphenol A and 4,4'-dichlorodiphenyl sulfone.

[0044] Non-ionic polymer suspending agents such as PEG4000, PEG6000, xanthan gum, etc. can be mixed with montmorillonite to improve the suspension stability of montmorillonite in non-polar solvents.

[0045] Among them, the organosilane is one of 3-aminopropyltriethoxysilane (APS), γ-(methacryloyloxy)propyltrimethoxysilane (KH570), trimethylchlorosilane and trimethylmethoxysilane.

[0046] 3-aminopropyltriethoxysilane (APS): This is a commonly used organosilane with 3 functional groups and is used for grafting montmorillonite.

[0047] γ-(methacryloyloxy)propyltrimethoxysilane (KH570): It can enhance the surface properties of montmorillonite and improve the grafting efficiency.

[0048] Trimethylchlorosilane and trimethylmethoxysilane: Montmorillonite reacts with these silanes to achieve organic modification.

[0049] In this embodiment, the preparation method of the montmorillonite surface-treated with an organosilane-modified organic cationic surfactant includes the following steps:

[0050] S1. Ultrasonic dispersion and decanter centrifuge classification: The montmorillonite suspension undergoes ultrasonic dispersion and decanter centrifuge classification to separate the light phase and the heavy phase. The montmorillonite particles in the light phase are smaller.

[0051] S2. The montmorillonite in the light phase is filtered through a sieve with a pore size less than 5 μm and centrifuged, and then spray-dried to obtain montmorillonite powder.

[0052] S3. The montmorillonite powder is washed with deionized water. After washing, it is centrifuged at 3500 rpm for 60 s. After pouring out the supernatant, it is repeatedly washed with deionized water until the pH value is 5 to obtain the washed montmorillonite powder. Due to the interaction between montmorillonite and interlayer water molecules during the dehydration and drying process, the montmorillonite powder particles are prone to agglomeration to form large particles, resulting in uneven montmorillonite powder particles and affecting its performance. By controlling the pH value during the washing process, the agglomeration of montmorillonite powder particles can be avoided, and the fineness and surface area of montmorillonite can be improved.

[0053] S4. After the final washing, 40 ml of the organic cationic surfactant is added to the ethanol aqueous solution at a volume ratio of 1:1, and then added to the washed montmorillonite powder and mixed at room temperature for 12 hours. After mixing, it is vacuum-filtered through a polypropylene membrane (Celgard LLC), and then dried in a vacuum at 100 °C for 12 hours to obtain the montmorillonite surface-modified with the organic cationic surfactant.

[0054] S5. Add the organosilane to the solvent benzyl phenyl ether and disperse it evenly. Then add the montmorillonite surface-modified by the organic cationic surfactant. The reaction is carried out at a temperature above the boiling point of the organosilane and the reaction time is 48 hours. After the reaction, the solvent benzyl phenyl ether is evaporated to obtain the montmorillonite surface-treated by the organosilane-modified organic cationic surfactant.

[0055] This embodiment also provides a method for preparing a reversible thermosensitive polymer functional dye, comprising the following steps:

[0056] S1. Measure the components of the color-changing core material according to the formula, mix them evenly, and obtain the color-changing core material;

[0057] S2, using the color-changing core material as the core material, adding a catalyst and a transparent polymer monomer into the core material, and stirring and mixing them evenly;

[0058] S3, adding a water-soluble emulsifier into deionized water, mixing it into the solution in step S2, stirring it to fully emulsify and disperse it, adopting an in-situ polymerization method to prepare transparent microcapsules, and after spray drying, a reversible thermosensitive polymer functional dye is obtained.

[0059] Under high temperature conditions, the color-changing dye and the developer are dissolved and dispersed in the solvent, and the system appears white. This is because under high temperature conditions, the solvent is in a liquid state. At this time, the interaction between the solvent and the developer is stronger than the interaction between the developer and the color-changing dye. The strength of this interaction determines the distance and state between the color-changing dye and the developer. As a result, the system appears colorless or white.

[0060] This embodiment uses microcapsule technology to encapsulate the organic reversible thermochromic material, which can improve its stability and protect the color-changing core material from environmental influences, thereby maintaining the stability of color contrast and decolorization rate.

[0061] Example 2

[0062] The reversible thermosensitive polymer functional dye provided in this embodiment includes a color-changing core material and a transparent microcapsule. The transparent microcapsule covers the color-changing core material. The color-changing core material is prepared from the following components: 10 parts of color-changing dye ODB, 28 parts of color developer BFPA, 210 parts of solvent benzyl phenyl ether, 15 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 125 parts of montmorillonite surface-treated with a cationic surfactant of dimethyl diallyl ammonium chloride modified by γ-(methacryloxy)propyltrimethoxysilane, 56 parts of non-ionic polymer suspending agent PEG6000, and 12 parts of ultraviolet absorber UV-326; the capsule wall of the transparent microcapsule is prepared from a transparent polytetrafluoroethylene propylene polymer.

[0063] In this embodiment, the preparation method of montmorillonite surface-treated with organosilane-modified organic cationic surfactant comprises the following steps:

[0064] S1. Ultrasonic dispersion and decanter centrifuge classification: The montmorillonite suspension is subjected to ultrasonic dispersion and decanter centrifuge classification to separate the light phase and the heavy phase. The montmorillonite particles in the light phase are smaller.

[0065] S2. The montmorillonite in the light phase is filtered through a sieve with a pore size less than 5 microns and centrifuged, and then spray-dried to obtain montmorillonite powder.

[0066] S3. The montmorillonite powder is washed with deionized water. After washing, it is centrifuged at 3500 rpm for 60 s. After pouring out the supernatant, it is repeatedly washed with deionized water until the pH value is 6 to obtain the washed montmorillonite powder. During the dehydration and drying process, due to the interaction between montmorillonite and interlayer water molecules, the montmorillonite powder particles are prone to agglomeration to form large particles, resulting in uneven particle size of the montmorillonite powder and affecting its performance. By controlling the pH value during the washing process, the agglomeration of montmorillonite powder particles can be avoided, and the fineness and surface area of montmorillonite can be improved.

[0067] S4. After the final washing, 40 ml of organic cationic surfactant is added to the ethanol aqueous solution at a volume ratio of 1:1, and then added to the washed montmorillonite powder and mixed at room temperature for 12 hours. After mixing, it is vacuum-filtered through a polypropylene membrane (Celgard LLC), and after filtration, it is dried in vacuo at 100 °C for 12 hours to obtain montmorillonite surface-modified with organic cationic surfactant.

[0068] S5. The organosilane is added to the solvent benzyl phenyl ether and dispersed evenly, and then the montmorillonite surface-modified with organic cationic surfactant is added. Under the temperature condition above the boiling point of the organosilane and with a reaction time of 65 h, after the reaction, the solvent benzyl phenyl ether is evaporated to obtain montmorillonite surface-treated with organosilane-modified organic cationic surfactant.

[0069] This embodiment also provides a preparation method of reversible thermosensitive polymer functional dye, comprising the following steps:

[0070] S1. Weigh each component of the color-changing core material according to the formula amount and mix them evenly to obtain the color-changing core material.

[0071] S2. Using the color-changing core material as the core material, a catalyst and monomers of a transparent polymer are added to the core material and stirred and mixed evenly.

[0072] S3. The water-soluble emulsifier is added to deionized water and mixed into the solution in step S2, and it is fully emulsified and dispersed by stirring. A transparent microcapsule is prepared by the method of in-situ polymerization, and after spray-drying, it is the reversible thermosensitive polymer functional dye.

[0073] Example 3

[0074] The reversible thermosensitive polymer functional dye provided in this example includes a color-changing core material and transparent microcapsules. The transparent microcapsules coat the color-changing core material. The color-changing core material is prepared from the following components: 12 parts of color-changing dye ODB1, 15 parts of developer BFPA, 400 parts of solvent benzyl phenyl ether, antioxidant 6 parts of 1010, 220 parts of montmorillonite surface-treated with trimethylchlorosilane-modified dimethyldiallylammonium chloride cationic surfactant, 82 parts of non-ionic polymer suspending agent xanthan gum, 5 parts of ultraviolet absorber UV-531; the capsule wall of the transparent microcapsules is prepared from polysulfone transparent polymer.

[0075] In this example, the preparation method of montmorillonite surface-treated with organosilane-modified organic cationic surfactant includes the following steps:

[0076] S1. Ultrasonic dispersion and decanter centrifuge classification: The montmorillonite suspension is subjected to ultrasonic dispersion and decanter centrifuge classification to separate the light phase and the heavy phase. The montmorillonite particles in the light phase are smaller.

[0077] S2. The montmorillonite in the light phase is filtered through a sieve with a pore size less than 5 μm and centrifuged, and then spray-dried to obtain montmorillonite powder.

[0078] S3. Wash the montmorillonite powder with deionized water. After washing, centrifuge at 3500 rpm for 60 s. After pouring out the supernatant, repeatedly wash with deionized water until the pH value is 5 - 6 to obtain the washed montmorillonite powder; during the dehydration and drying process, due to the interaction between montmorillonite and interlayer water molecules, the montmorillonite powder particles are prone to agglomeration to form large particles, resulting in uneven montmorillonite powder particles and affecting its performance. By controlling the pH value during the washing process, the agglomeration of montmorillonite powder particles can be avoided, and the fineness and surface area of montmorillonite can be improved.

[0079] S4. After the final washing, 40 ml of organic cationic surfactant is added to the ethanol aqueous solution at a volume ratio of 1:1, and then added to the washed montmorillonite powder and mixed at room temperature for 12 hours. After mixing, vacuum filter through a polypropylene membrane (Celgard LLC), and dry in a vacuum at 100 °C for 12 hours to obtain montmorillonite surface-modified with organic cationic surfactant.

[0080] S5. Add organosilane to the solvent benzyl phenyl ether and disperse evenly, then add montmorillonite surface-modified with organic cationic surfactant, react at a temperature above the boiling point of organosilane for 72 h, and evaporate the solvent benzyl phenyl ether after the reaction to obtain montmorillonite surface-treated with organosilane-modified organic cationic surfactant.

[0081] This embodiment also provides a preparation method of a reversible thermosensitive polymer functional dye, which includes the following steps:

[0082] S1. Weigh each component of the color-changing core material according to the formulated amount, mix them evenly to obtain the color-changing core material;

[0083] S2. Take the color-changing core material as the core material, add a catalyst and monomers of a transparent polymer to the core material, and stir and mix them evenly;

[0084] S3. Add a water-soluble emulsifier to deionized water, mix it into the solution in step S2, and make it fully emulsified and dispersed by stirring. Then, prepare transparent microcapsules by the in-situ polymerization method. After spray drying, it is the reversible thermosensitive polymer functional dye.

[0085] Example 4

[0086] The reversible thermosensitive polymer functional dye provided in this embodiment includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with an aminopropyltriethoxysilane-modified bis(hydrogenated tallow-based) benzylmethylammonium chloride cationic surfactant, 65 parts of non-ionic polymer suspending agent PEG4000, 5 parts of urea, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone. The capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0087] Example 5

[0088] The reversible thermosensitive polymer functional dye provided in this embodiment includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 16 parts of developer BFPA, 240 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with an aminopropyltriethoxysilane-modified bis(hydrogenated tallow-based) benzylmethylammonium chloride cationic surfactant, 65 parts of non-ionic polymer suspending agent PEG4000, 5 parts of urea, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone. The capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0089] In this embodiment, the weight ratio of thermosensitive black ODB: developer BFPA: solvent benzyl phenyl ether is 1:2:30.

[0090] Comparative Example 1

[0091] Different from Example 1, the reversible thermosensitive polymer functional dye provided in this comparative example includes a color-changing core material and transparent microcapsules. The transparent microcapsules coat the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with bis(hydrogenated tallow) benzyl methyl ammonium chloride cationic surfactant, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0092] The preparation of the montmorillonite surface-treated with bis(hydrogenated tallow) benzyl methyl ammonium chloride cationic surfactant and the reversible thermosensitive polymer functional dye in this comparative example refers to Example 1.

[0093] Comparative Example 2

[0094] Different from Example 1, the reversible thermosensitive polymer functional dye provided in this comparative example includes a color-changing core material and transparent microcapsules. The transparent microcapsules coat the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite, 65 parts of non-ionic polymer suspending agent PEG4000, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0095] Comparative Example 3

[0096] Different from Example 1, the reversible thermosensitive polymer functional dye provided in this comparative example includes a color-changing core material and transparent microcapsules. The transparent microcapsules coat the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 65 parts of non-ionic polymer suspending agent PEG4000, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0097] Comparative Example 4

[0098] Different from Example 1, the reversible thermosensitive polymer functional dye provided in this comparative example includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent phenyl benzoate, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with aminopropyltriethoxysilane-modified di(hydrogenated tallow-based) benzylmethylammonium chloride cationic surfactant, 65 parts of non-ionic polymer suspending agent PEG4000, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0099] Comparative Example 5

[0100] Different from Example 1, the reversible thermosensitive polymer functional dye provided in this comparative example includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzophenone, 8 parts of antioxidant 2,6-di-tert-butyl-p-cresol, 160 parts of montmorillonite surface-treated with aminopropyltriethoxysilane-modified di(hydrogenated tallow-based) benzylmethylammonium chloride cationic surfactant, 65 parts of non-ionic polymer suspending agent PEG4000, and 8 parts of ultraviolet absorber 2,4-dihydroxybenzophenone; the capsule wall of the transparent microcapsules is prepared from a polytetrafluoroethylene transparent polymer.

[0101] Experimental Example

[0102] Measurement of color contrast:

[0103] By comparing the ratio of the reflectance after the color development end point and complete color fading, the contrast degree of the system color was judged and defined as the contrast between the two. By comparing these color changes, the influence of the interaction between the solvent and the developer on the color contrast and color change sensitivity was studied.

[0104] Weigh 0.045 g of the reversible thermosensitive polymer functional dyes provided in Examples 1 to 4 and Comparative Examples 1 - 5, place them within an area of 1.5 cm × 1.5 cm on a glass slide, heat the sample to completely decolorize it, then cover it with a cover glass and let it cool naturally. Use an X-Rite EyeOne Pro colorimeter to measure the reflectance of the sample at the melting point temperature of its respective solvent, and use a blank glass slide and cover glass as a reference to correct the reflectance of the sample. The measurement results of Examples 1 to 4 and Comparative Examples 1 - 5 are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] When the value of the color contrast reaches above 12.0, the human eye feels a very strong change in color, and it can be considered that one color has changed into another color. As shown in Table 1, compared with Comparative Examples 1-5, the color contrasts of the reversible thermosensitive polymer functional dyes provided in Examples 1-4 are all above 12, and the color contrast is very high. Among them, urea is added in Example 4. The reason for urea as a hydrogen bond breaker is that it itself serves as both a strong hydrogen bond acceptor and donor, competing for the hydrogen bond sites on BFPA, breaking the hydrogen bonds of the complex of BFPA and thermosensitive black ODB, promoting the separation of BFPA and thermosensitive black ODB, and the color contrast of the reversible thermosensitive polymer functional dye is higher; the color contrast of the reversible thermosensitive polymer functional dye provided in Comparative Example 3 is the lowest, that is, when the solvent is benzyl phenyl ether and montmorillonite is not added, the color contrasts of the reversible thermosensitive polymer functional dyes provided in Comparative Examples 4 and 5 are both higher than that of Comparative Example 3, indicating that when the solvents are benzophenone and phenyl benzoate, the interaction between benzophenone and phenyl benzoate and the color developer BFPA is greater than that of benzyl phenyl ether. On the basis of Comparative Example 3, the color contrasts of the reversible thermosensitive polymer functional dyes provided in Comparative Examples 1 and 2 are both higher than those of Comparative Examples 4 and 5, indicating that after adding montmorillonite or being surface-treated with an organic cationic surfactant or silane modification, the color contrast of the reversible thermosensitive polymer functional dye is significantly improved.

[0109] The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention all belong to the scope of protection required by the present invention.

Claims

1. A reversible thermosensitive polymeric functional dye, characterized in that, It includes a color-changing core material and transparent microcapsules. The transparent microcapsules encapsulate the color-changing core material. The color-changing core material is prepared from the following components: 8-12 parts of color-changing dye ODB, 15-28 parts of developer BFPA, 210-400 parts of solvent benzyl phenyl ether, 6-15 parts of antioxidant, 125-220 parts of montmorillonite surface-treated with an organosilane-modified organic cationic surfactant, 56-82 parts of non-ionic polymer suspending agent, 1-5 parts of urea, and 5-12 parts of ultraviolet absorber; the capsule wall of the transparent microcapsules is prepared from a transparent polymer, and the transparent polymer is one of polytetrafluoroethylene, polytetrafluoroethylene-propylene, and polysulfone.

2. The reversible thermosensitive polymer functional dye according to claim 1, wherein The color-changing core material is prepared from the following components: 8 parts of color-changing dye ODB, 25 parts of developer BFPA, 300 parts of solvent benzyl phenyl ether, 8 parts of antioxidant, 160 parts of montmorillonite surface-treated with an organosilane-modified organic cationic surfactant, 65 parts of non-ionic polymer suspending agent, 5 parts of urea, and 8 parts of ultraviolet absorber.

3. The reversible thermosensitive polymer functional dye according to claim 1, wherein The ultraviolet absorber is 2,4-dihydroxybenzophenone, UV-326, and UV-531, which can further improve the light aging resistance of the material.

4. The reversible thermosensitive polymer functional dye according to claim 1, wherein The non-ionic polymer suspending agent is one or a mixture of PEG4000, PEG6000, and xanthan gum.

5. The reversible thermosensitive polymer functional dye according to claim 1, wherein The weight ratio of the thermosensitive black ODB: the developer BFPA: the solvent benzyl phenyl ether is 1:2:

30.

6. The reversible thermosensitive polymer functional dye according to claim 1, wherein The organic cationic surfactant is one or two of bis(hydrogenated tallow-based) benzyl methyl ammonium chloride and dimethyldiallyl ammonium chloride.

7. The reversible thermosensitive polymer functional dye according to claim 1, wherein, The antioxidant is one or both of 2,6-di-tert-butyl-p-cresol and 1010.

8. The reversible thermosensitive polymeric functional dye according to claim 1, characterized in that, The organosilane is one of 3-aminopropyltriethoxysilane, γ-(methacryloxy)propyltrimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane.

9. The reversible thermosensitive polymeric functional dye according to claim 8, wherein, The preparation method of the montmorillonite surface-treated with an organosilane-modified organic cationic surfactant includes the following steps: S1. Ultrasonic dispersion and decanter centrifuge classification: The montmorillonite suspension undergoes ultrasonic dispersion and decanter centrifuge classification to separate the light phase and the heavy phase. The montmorillonite particles in the light phase are smaller. S2. The montmorillonite in the light phase is filtered through a sieve with a pore size less than 5 microns and centrifuged, and then spray-dried to obtain montmorillonite powder. S3. The montmorillonite powder is washed with deionized water. After washing, it is centrifuged at 3500 rpm for 60 s. After pouring out the supernatant, it is repeatedly washed with deionized water until the pH value is 5-6 to obtain the washed montmorillonite powder. S4. After the final washing, 40 ml of the organic cationic surfactant is added to the ethanol aqueous solution at a volume ratio of 1:1, and then added to the washed montmorillonite powder and mixed at room temperature for 12 hours. After mixing, it is vacuum-filtered through a polypropylene membrane and dried in a vacuum at 100 °C for 12 hours to obtain the montmorillonite surface-modified with an organic cationic surfactant. S5. Add the organosilane to the solvent benzyl phenyl ether, disperse it evenly, then add the montmorillonite surface-modified with the organic cationic surfactant, and react at a temperature above the boiling point of the organosilane for 48 h - 72 h. After the reaction, evaporate the solvent benzyl phenyl ether to obtain the montmorillonite surface-treated with the organosilane-modified organic cationic surfactant.

10. The preparation method of the reversible thermosensitive polymeric functional dye according to any one of claims 1-9, characterized in that, It includes the following steps: S1. Measure each component of the color-changing core material according to the formula amount, and mix them evenly to obtain the color-changing core material; S2. Take the color-changing core material as the core material, add a catalyst and the monomer of the transparent polymer to the core material, and stir and mix them evenly; S3. Add the water-soluble emulsifier to deionized water, mix it into the solution in step S2, and make it fully emulsified and dispersed by stirring. The transparent microcapsules are prepared by the method of in-situ polymerization. After spray drying, it is the reversible thermosensitive polymer functional dye.

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