Photochromic agent, photochromic anti-counterfeiting silicone adhesive as well as preparation method and application of photochromic agent and photochromic anti-counterfeiting silicone adhesive

Abstract

The invention discloses a photochromic agent, a photochromic anti-counterfeiting silicone adhesive as well as a preparation method and application of the photochromic anti-counterfeiting silicone adhesive, and belongs to the technical field of high polymer materials. The molecular structure of the photochromic agent contains (CH2) n-SiR ''3, the photochromic agent has good compatibility and stability in a silicone adhesive, layering and influence on discoloration caused by poor compatibility of the photochromic agent and a system are solved, meanwhile, negative influence on the transparency and mechanical property of the sealant is avoided, and the photochromic agent has good application prospects. The photochromic agent is high in color changing speed, the color changes within 3 seconds after ultraviolet treatment, and the color becomes darker and darker along with the prolonging of irradiation time and is finally stable; according to the photochromic agent, after ultraviolet irradiation is finished, the color can disappear slowly, color disappearance can be accelerated when a fluorescent lamp is used for coloring, and the photochromic agent has excellent reversibility (that is, the color is changed when ultraviolet irradiation is carried out, an ultraviolet light source is moved away or white light irradiation is carried out, and the color is gradually recovered to a colorless and transparent state).

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a photochromic agent, a photochromic anti-counterfeiting silicone adhesive, and a preparation method and application thereof. Background Art

[0002] Silicone sealants can be used as adhesives, sealants and potting agents, etc. They have good bonding effects on metals, glass, doors and windows and other materials. They are widely used in curtain walls, construction, electronic appliances, automobiles, aviation and other fields, and are indispensable materials for sealing and bonding in daily life. With the continuous development of the silicone sealant market, counterfeit and inferior silicone sealant products frequently appear, and the quality varies. It is difficult for consumers to accurately distinguish the authenticity of the products. For quality problems that occur during use, it is difficult for manufacturers to identify their products through effective means and effectively handle consumer demands, resulting in difficulties for consumers and manufacturers in safeguarding their own rights and interests. Therefore, it is very necessary to develop anti-counterfeiting for silicone sealants, which is of great significance for the identification, quality assurance, consumer rights protection and market stability of silicone sealants.

[0003] Photochromic materials have significant advantages in remote control, instantaneity, signal stability and environmental protection due to their specific photochromic properties, and are widely used in many fields such as information storage, light-controlled devices, security and anti-counterfeiting technology, and decoration. Light-stimulated responsive molecules will undergo structural changes under specific wavelengths of light, which are sometimes accompanied by color changes on a macro scale. Under another wavelength of light or in a dark field, the molecular structure will return to its original structure and the color will fade.

[0004] At present, most of the commonly used organic photochromic compounds are spiropyran, azobenzene, spirooxazine, fulgide, diarylethene, etc., but not all of them are suitable for the development of anti-counterfeiting silicone sealants. It is also necessary to consider the compatibility and stability of the photochromic compound with the silicone sealant to ensure that the addition of the photochromic compound will not affect the adhesive performance and appearance of the sealant. In addition, the production cost of the manufacturer must also be considered. While achieving the photochromic anti-counterfeiting function, it also has certain economic benefits. Therefore, it is very important to select a suitable organic photochromic agent and a reasonable component configuration to obtain a reversible photochromic anti-counterfeiting silicone sealant.

[0005] Patent CN104974710A discloses a dealcoholized anti-counterfeiting silicone sealant, which achieves the anti-counterfeiting effect by adding a photochromic agent to the dealcoholized silicone sealant, but the photochromic agent is an inorganic metal compound, such as transition metal oxides, metal halides, rare earth complexes, etc. However, this type of photochromic agent has the following disadvantages: 1. Slow photochromic response speed; 2. Poor reversibility of color change; 3. Limited color change range; 4. Limited application in transparent adhesives, which will affect transparency; 5. When used in sealants, due to the large particle size, the mechanical properties of the sealant will be reduced.

[0006] Patent CN 108913062A discloses a photosensitive color-changing environmentally friendly sealant and a preparation method thereof, which realizes color change by adding photosensitive color-changing powder to the environmentally friendly sealant, and the color-changing powder includes spiropyran, rutin, azo compounds, etc. It further discloses that the coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and N-β-aminoethyl-γ-aminopropyltrimethoxysilane; spiropyran is in a closed-loop state under no light conditions and appears colorless; when irradiated with light of a specific wavelength, spiropyran will undergo photochromism, changing from colorless to colored. The silane coupling agent in silicone sealant is alkaline to a certain extent. When preparing a sealant with spiropyran as a photosensitizer, the color change can be normal in the first few steps. However, after adding the amino-containing coupling agent in the last step, the sealant appears yellow and does not have the color change function. This is because the addition of amino groups will affect the stability of spiropyran, which is prone to ring-opening reactions, increasing the proportion of ring-opened spiropyran. Under this condition, ring-opened spiropyran usually appears yellow, so yellowing will be observed after mixing.

[0007] In view of this, this application is filed. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a photochromic agent, a photochromic anti-counterfeiting silicone sealant, and a preparation method and application thereof. The photochromic agent has good compatibility and stability in silicone sealant, solves the stratification and effect on discoloration caused by the poor compatibility of the photochromic agent with the system, and does not have a negative impact on the transparency and mechanical properties of the sealant itself.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A photochromic agent, the structural formula of which is shown in Formula I:

[0011]

[0012] In formula I, R' is selected from one of hydrogen, methyl or phenyl, R" is selected from one of methoxy, ethoxy and butanone oxime; and n is an integer ≥1.

[0013] The photochromic agent of the present invention contains (CH2)n-SiR"3 in its molecular structure, which has good compatibility and stability in silicone adhesive, solves the delamination and influence on discoloration caused by the poor compatibility of the photochromic agent with the system, and does not have a negative impact on the transparency and mechanical properties of the sealant itself. The photochromic agent has a fast discoloration speed. After being treated with ultraviolet rays, the discoloration occurs within 3 seconds. As the irradiation time increases, the color becomes darker and darker, and finally reaches stability. Moreover, the color of the photochromic agent gradually disappears after the ultraviolet irradiation ends. Coloring with a fluorescent lamp can accelerate the disappearance of the color, and has excellent reversibility (i.e., the color changes under ultraviolet light, and gradually returns to a colorless and transparent state after the ultraviolet light source is removed or irradiated with white light).

[0014] The photochromic agent described in the present invention contains (CH2)n-SiR"3 in its molecular structure. The introduction of the (CH2)n-SiR"3 structure has excellent weather resistance while ensuring the original performance of the sealant. After being treated with salt spray, high temperature, and high temperature and high humidity, it can still respond to rapid color change and has excellent aging resistance.

[0015] The present invention also provides a method for preparing a photochromic agent, comprising the following steps:

[0016] (1) reacting compound 1 and tributyl borate in the presence of a first solvent and a first catalyst, extracting, washing the aqueous phase, filtering, and drying to obtain compound 2;

[0017] (2) heating the modifier and compound 2 under reflux in the presence of a second solvent, a second catalyst and a pH adjuster, extracting, and drying the organic phase to obtain compound 3;

[0018] (3) reacting compound 3 and perfluorocyclopentene in the presence of a third solvent and a third catalyst, extracting, and drying the organic phase to obtain a photochromic agent;

[0019] The structural formula of compound 1 is as follows:

[0020]

[0021] Wherein, R' in compound 1 is selected from one of hydrogen, methyl or phenyl;

[0022] The structural formula of the modifier is as follows:

[0023]

[0024] Wherein, R" in the modifier is selected from one of methoxy, ethoxy and butanone oxime; and n is an integer ≥1.

[0025] The reaction process involved in the photochromic agent of the present invention is as follows:

[0026]

[0027] As a preferred embodiment of the present invention, the molar ratio of the compound 1 to tributyl borate is 1:(0.8-1.2).

[0028] As a preferred embodiment of the present invention, the molar ratio of the modifier to the compound 2 is 1:(0.8-1.2).

[0029] As a preferred embodiment of the present invention, the molar ratio of the compound 3 to perfluorocyclopentene is 1:(1.8-2.2).

[0030] As a preferred embodiment of the present invention, the first solvent, the second solvent and the third solvent are each independently selected from at least one of diethyl ether, methyl ether, dipropyl ether, tetrahydrofuran and 2-methyltetrahydrofuran.

[0031] As a preferred embodiment of the present invention, the first catalyst and the third catalyst are independently selected from at least one of n-butyl lithium, neodymium neodecanoate, bismuth cyclohexaneate, diethylaluminum chloride, dibutyltin dilaurate, stannous octoate, and bismorpholine diethyl ether.

[0032] As a preferred embodiment of the present invention, the second catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium and tetrakis(triphenylphosphine)platinum.

[0033] As a preferred embodiment of the present invention, the reaction temperature in step (1) is 20 to 50° C., and the reaction time is 1 to 3 hours.

[0034] As a preferred embodiment of the present invention, the heating reflux reaction time is 16 to 20 hours; and / or

[0035] As a preferred embodiment of the present invention, the reaction temperature of step (3) is 20 to 50° C., and the reaction time is 1 to 3 hours.

[0036] It should be noted that in the method for preparing the photochromic agent of the present invention, there is no limit on the amount of catalyst (including the first catalyst, the second catalyst, and the third catalyst) and solvent (including the first solvent, the second solvent, and the third solvent). Those skilled in the art can adjust the amount of catalyst and solvent according to conventional technical means in the art, wherein the solvent is sufficient to provide a reaction environment and the catalyst is sufficient to catalyze the reaction.

[0037] Exemplarily, the molar ratio of the compound 1 to the first catalyst is 1:(0.1-2).

[0038] Illustratively, the mass ratio of the compound 1 to the first solvent is 1:(4-100).

[0039] Illustratively, in step (1), a dilute hydrochloric acid solution (0.1-1 mol / L) can be added to terminate the reaction according to the situation.

[0040] Exemplarily, the mass ratio of the compound 2 to the second solvent is 1:(4-100).

[0041] Exemplarily, the molar ratio of the compound 2 to the second catalyst is 1:(0.01-0.1).

[0042] Exemplarily, the pH adjuster is a sodium carbonate solution with a molar concentration of 1.5 to 2.5 mol / L.

[0043] The pH regulator is added to adjust the pH to 9-11.

[0044] Exemplarily, the molar ratio of the compound 3 to the third catalyst is 1:(0.1-2).

[0045] Exemplarily, the mass ratio of the compound 3 to the third solvent is 1:(4-100).

[0046] The invention also provides an application of a photochromic agent in the preparation of silicone adhesive.

[0047] The present invention also provides a photochromic anti-counterfeiting silicone adhesive, comprising the following components in parts by weight: 100 parts of hydroxyl-terminated polydimethylsiloxane, 1 to 30 parts of plasticizer, 10 to 25 parts of filler, 5 to 10 parts of cross-linking agent, 0.5 to 2 parts of coupling agent, 0.05 to 0.1 parts of catalyst, and 0.001 to 1.5 parts of photochromic agent;

[0048] The photochromic agent includes the photochromic agent described above.

[0049] Among them, in the specific silicone adhesive system described in the present invention, the photochromic agent has excellent compatibility and stability, which solves the stratification and discoloration caused by the poor compatibility of the photochromic agent with the system, and does not have a negative impact on the transparency and mechanical properties of the sealant itself. The photochromic agent has a fast light color speed. After ultraviolet treatment, the color changes within 3 seconds. As the irradiation time increases, the color will become darker and darker, and finally reach stability; and the photochromic agent, when the ultraviolet irradiation ends, the color will slowly disappear. Coloring with a fluorescent lamp can accelerate the disappearance of the color, and has excellent reversibility (i.e., ultraviolet light changes color, and the ultraviolet light source is removed or white light is used to irradiate, and the color gradually returns to a colorless and transparent state).

[0050] As a preferred embodiment of the present invention, the amount of the photochromic agent is 0.05 to 0.5 parts.

[0051] As a preferred embodiment of the present invention, the following components are included in parts by weight: 100 parts of hydroxyl-terminated polydimethylsiloxane, 10 to 20 parts of plasticizer, 15 to 20 parts of filler, 6 to 8 parts of crosslinking agent, 1 to 1.5 parts of coupling agent, 0.06 to 0.08 parts of catalyst, and 0.1 to 0.13 parts of photochromic agent.

[0052] As a preferred embodiment of the present invention, the viscosity of the hydroxyl-terminated polydimethylsiloxane at 25° C. is 10,000 to 200,000 mPa·s.

[0053] The plasticizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25° C. is 100 to 20,000 mpa·s.

[0054] As a preferred embodiment of the present invention, the crosslinking agent includes at least one of methyltrimethoxysilane or its oligomer, vinyltrimethoxysilane or its oligomer, propyltrimethoxysilane or its oligomer, methyl silicate, ethyl silicate, methyltributylacetoximate silane, vinyltributylacetoximate silane, dimethyldibutylketoxime silane, and tetrabutylketoxime silane.

[0055] As a preferred embodiment of the present invention, the coupling agent is a reactant of an aminosilane coupling agent and an acrylate coupling agent.

[0056] The aminosilane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0057] The acrylate coupling agent includes at least one of γ-acryloxypropyl trimethoxysilane, γ-methacryloxypropyl triisopropoxysilane, 3-(acryloxy)methyldimethoxysilane, and 3-methacryloxypropyl triethoxysilane.

[0058] The molar ratio of the aminosilane coupling agent to the acrylate coupling agent is 1:(0.8-1.2). The coupling agent is a reactant of an aminosilane coupling agent and an acrylate coupling agent, wherein the aminosilane coupling agent reacts with the acrylate to form a Michael addition reaction, which effectively reduces the alkalinity of the aminosilane coupling agent so that it will not affect the discoloration of the photochromic agent, while retaining the adhesion of the aminosilane coupling agent. As a preferred embodiment of the present invention, the filler is fumed silica, and the specific surface area of ​​the fumed silica is 130-400 m 2 / g.

[0059] As a preferred embodiment of the present invention, the catalyst includes at least one of dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, dioctyltin dilaurate, and titanate.

[0060] The present invention also provides a method for preparing a photochromic anti-counterfeiting silicone adhesive, comprising the following steps:

[0061] The hydroxyl-terminated polydimethylsiloxane, the plasticizer, the cross-linking agent and the photochromic agent are mixed evenly, the filler is added and mixed evenly, and finally the coupling agent and the catalyst are added and mixed evenly to obtain the photochromic anti-counterfeiting silicone adhesive.

[0062] The present invention also provides an application of the photochromic anti-counterfeiting silicone adhesive in building curtain walls, metals, ceramics, plastics, doors and windows, rubber, electronic components, optical devices, rail transportation fields, and automobiles.

[0063] The beneficial effects of the present invention are as follows: the photochromic agent described in the present invention contains (CH2)n-SiR"3 in its molecular structure, which has good compatibility and stability in silicone adhesive, solves the stratification and discoloration caused by the poor compatibility of the photochromic agent with the system, and does not have a negative impact on the transparency and mechanical properties of the sealant itself. The photochromic agent has a fast photochromic speed. After being treated with ultraviolet rays, the color changes within 3 seconds. As the irradiation time increases, the color becomes darker and darker, and finally reaches stability. Moreover, the color of the photochromic agent slowly disappears after the ultraviolet irradiation ends. Coloring with a fluorescent lamp can accelerate the disappearance of the color, and has excellent reversibility (i.e., the color changes under ultraviolet light, and gradually returns to a colorless and transparent state after the ultraviolet light source is removed or irradiated with white light). DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0065] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0066] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0067] In the present application, there is no particular limitation on the specific dispersion, stirring, filtering and extraction treatment methods.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0069] The raw materials used in the embodiments and comparative examples are described as follows:

[0070] Hydroxyl-terminated polydimethylsiloxane: viscosity at 25°C is 80,000 mPa·s, Xin'an Chemical, brand RTV-107-8.

[0071] Dimethyl silicone oil: Viscosity is 100 mPa·s at 25°C. Brand: 201-100.

[0072] Filler: Fumed silica, specific surface area 180m 2 / g, commonly available in the market.

[0073] Catalyst: dibutyltin dilaurate, commonly available in the market.

[0074] Crosslinking agent: methyl tributylidene oxime silane and vinyl tributylidene oxime silane, the mixing ratio of the two is (4-8:1). For the convenience of comparison, the following examples all use a mass ratio of 5:1, which is conventionally available on the market.

[0075] Coupling agent-1: a reaction product of γ-aminopropyltriethoxysilane and acrylate.

[0076] Coupling agent-2: a reaction product of γ-aminopropyltrimethoxysilane and acrylate.

[0077] The preparation method of coupling agents 1 and 2 is as follows: add 1 mol of γ-aminopropyltriethoxysilane (coupling agent 2 is γ-aminopropyltrimethoxysilane) to a 1000 ml four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, add 1 mol of γ-acryloxypropyltrimethoxysilane to the dropping funnel, slowly drop it into the flask, and finish dropping it in 3 hours. Slowly raise the temperature to 80°C, continue the reaction for 5 hours, and finally obtain a light yellow transparent liquid as the product.

[0078] Coupling agent-3: γ-aminopropyltriethoxysilane.

[0079] The preparation methods of photochromic agents 1 to 3 are as follows: (1) dissolving compound 1 in ether, adding n-butyl lithium and tributyl borate under nitrogen protection, reacting at 25° C. for 1.5 h, extracting the organic phase, washing the aqueous phase to neutrality, filtering, and drying to obtain compound 2; wherein the molar ratio of compound 1, n-butyl lithium, and tributyl borate is 1:1:1.05;

[0080] (2) dissolving the modifier and tetrakis(triphenylphosphine)palladium in tetrahydrofuran, adding compound 2, adjusting the pH to 10 with 2 mol / L sodium carbonate solution, heating under reflux for 18 h, cooling to room temperature, extracting, and drying the organic phase to obtain compound 3; wherein the molar ratio of the modifier, compound 2, and tetrakis(triphenylphosphine)palladium is 1:1:0.05;

[0081] (3) Compound 3 is dissolved in tetrahydrofuran, and under nitrogen protection, n-butyl lithium and perfluorocyclopentene are added, reacting at 25° C. for 1.5 h, extracting, and drying the organic phase to obtain a photochromic agent; the molar ratio of compound 3, n-butyl lithium, and perfluorocyclopentene is 1:1:2;

[0082] The structural formula of compound 1 for preparing photochromic agent-1 is as follows:

[0083]

[0084] Wherein, R' in the compound 1 for preparing the photochromic agent-1 is hydrogen;

[0085] The structural formula of the modifier for preparing the photochromic agent-1 is as follows:

[0086]

[0087] Wherein, R" in the modifier for preparing the photochromic agent-1 is a methoxy group; and n is 1.

[0088] The structural formula of compound 1 for preparing photochromic agent-2 is as follows:

[0089]

[0090] Wherein, R' in compound 1 is hydrogen;

[0091] The structural formula of the modifier for preparing the photochromic agent-2 is as follows:

[0092]

[0093] Wherein, R" in the modifier for preparing photochromic agent-2 is ethoxy; and n is 2.

[0094] The structural formula of compound 1 for preparing photochromic agent-3 is as follows:

[0095]

[0096] Wherein, R' in compound 1 for preparing photochromic agent-3 is methyl;

[0097] The structural formula of the modifier for preparing the photochromic agent-3 is as follows:

[0098]

[0099] Wherein, R" in the modifier for preparing the photochromic agent-3 is a butanone oxime group; and n is 4.

[0100] Photochromic agent-4: The preparation methods of photochromic agent-4 and photochromic agent-1 are exactly the same, except that the modifier used to prepare photochromic agent-4 is different.

[0101] The structural formula of the modifier for preparing photochromic agent-4 is shown below:

[0102]

[0103] Photochromic agent-5: molybdenum trioxide.

[0104] Photochromic agent-6: spiropyran.

[0105] Photochromic agent-7: 1,2-bis(2,5-dimethylthiophen-3-yl)perfluorocyclopentene.

[0106] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0107] Examples 1 to 7, Comparative Examples 1 to 5

[0108] The formulas of the photochromic anti-counterfeiting silicone adhesives of Examples 1 to 7 and Comparative Examples 1 to 5 are shown in Table 1 (all parts by weight in the table).

[0109] The hydroxyl-terminated polydimethylsiloxane, the plasticizer, the cross-linking agent and the photochromic agent are mixed evenly, the filler is added and mixed evenly, and finally the coupling agent and the catalyst are added and mixed evenly to obtain the photochromic anti-counterfeiting silicone adhesive.

[0110] Table 1

[0111]

[0112]

[0113] Performance Testing

[0114] (1) 100% modulus: tested in accordance with the test method for tensile modulus in GB / T 13477.8-2017.

[0115] (2) Elongation: Test according to the method specified in 6.8.4 of GB / T 16776.

[0116] (3) Transmittance / haze: Use a transmittance instrument to test the transmittance and haze of the film and record them.

[0117] (4) Color change time: Use a stopwatch to time the process from the start of ultraviolet irradiation until the color change occurs.

[0118] (5) Color change time after double 85: Place the film in a high temperature and high humidity box at a temperature of 85°C and a humidity of 85% RH for 1000 hours, take it out and put it back to room temperature, and then start the irradiation timing.

[0119] Table 2

[0120]

[0121] It can be seen from Table 2 that the photochromic anti-counterfeiting adhesive of the present invention has excellent mechanical properties, color-changing effect and color-changing stability.

[0122] From the comparison of Examples 1 to 4, it can be seen that the present invention can obtain a silicone adhesive with better comprehensive performance by controlling the amount of each raw material to: 100 parts of hydroxyl-terminated polydimethylsiloxane, 10 to 20 parts of plasticizer, 15 to 20 parts of filler, 6 to 8 parts of cross-linking agent, 1 to 1.5 parts of coupling agent, 0.06 to 0.08 parts of catalyst, and 0.1 to 0.13 parts of photochromic agent.

[0123] By comparing Example 3 with Comparative Example 1, it can be seen that the specific coupling agent used in the present invention can significantly improve the mechanical properties and color change effect.

[0124] By comparing Example 3 with Comparative Examples 2 to 5, it can be seen that the photochromic agent of the present invention can significantly improve the color changing effect and has excellent stability.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A photochromic agent, characterized in that: Its structural formula is shown in Formula I: In formula I, R' is selected from one of hydrogen, methyl or phenyl, R" is selected from one of methoxy, ethoxy and butanone oxime; and n is an integer ≥1.

2. The method for preparing a photochromic agent according to claim 1, characterized in that: The following steps are involved: (1) reacting compound 1 and tributyl borate in the presence of a first solvent and a first catalyst, extracting, washing the aqueous phase, filtering, and drying to obtain compound 2; (2) heating the modifier and compound 2 under reflux in the presence of a second solvent, a second catalyst and a pH adjuster, extracting, and drying the organic phase to obtain compound 3; (3) reacting compound 3 and perfluorocyclopentene in the presence of a third solvent and a third catalyst, extracting, and drying the organic phase to obtain a photochromic agent; The structural formula of compound 1 is shown below: Wherein, R' in compound 1 is selected from one of hydrogen, methyl or phenyl; The structural formula of the modifier is shown below: Wherein, R" in the modifier is selected from one of methoxy, ethoxy and butanone oxime; and n is an integer ≥1.

3. The method for preparing a photochromic agent according to claim 2, characterized in that: The molar ratio of the compound 1 to tributyl borate is 1:(0.8-1.2); and / or The molar ratio of the modifier to the compound 2 is 1:(0.8-1.2); and / or The molar ratio of the compound 3 to perfluorocyclopentene is 1:(1.8-2.2).

4. The method for preparing a photochromic agent according to claim 2, characterized in that: The first solvent, the second solvent, and the third solvent are each independently selected from at least one of diethyl ether, methyl ether, dipropyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran; and / or The first catalyst and the third catalyst are each independently selected from at least one of n-butyl lithium, neodymium neodecanoate, bismuth naphthenate, diethylaluminum chloride, dibutyltin dilaurate, stannous octoate, and bismorpholine diethyl ether; and / or The second catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium and tetrakis(triphenylphosphine)platinum.

5. The method for preparing a photochromic agent according to claim 2, characterized in that: The reaction temperature in step (1) is 20 to 50° C. and the reaction time is 1 to 3 hours; and / or The heating reflux reaction time in step (2) is 16 to 20 hours; and / or The reaction temperature of step (3) is 20-50° C., and the reaction time is 1-3 hours.

6. Use of the photochromic agent according to claim 1 in the preparation of silicone adhesive.

7. A photochromic anti-counterfeiting silicone adhesive, characterized in that: The invention comprises the following components in parts by weight: 100 parts of hydroxyl-terminated polydimethylsiloxane, 1 to 30 parts of plasticizer, 10 to 25 parts of filler, 5 to 10 parts of crosslinking agent, 0.5 to 2 parts of coupling agent, 0.05 to 0.1 parts of catalyst, and 0.001 to 1.5 parts of photochromic agent; The photochromic agent comprises the photochromic agent according to claim 1.

8. The photochromic anti-counterfeiting silicone adhesive according to claim 7, characterized in that: The viscosity of the hydroxyl-terminated polydimethylsiloxane at 25° C. is 10,000 to 200,000 mPa·s; and / or The plasticizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25° C. is 100 to 20,000 mpa·s.

9. The photochromic anti-counterfeiting silicone adhesive according to claim 7, characterized in that: The crosslinking agent includes at least one of methyltrimethoxysilane or its oligomer, vinyltrimethoxysilane or its oligomer, propyltrimethoxysilane or its oligomer, methyl silicate, ethyl silicate, methyltributylacetoximate silane, vinyltributylacetoximate silane, dimethyldibutylketoxime silane, and tetrabutylketoxime silane; and / or The coupling agent is a reactant of an aminosilane coupling agent and an acrylate coupling agent, wherein the aminosilane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; and the acrylate coupling agent includes at least one of γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)methyldimethoxysilane, and 3-methacryloxypropyltriethoxysilane.

10. Use of the photochromic anti-counterfeiting silicone adhesive according to any one of claims 7 to 9 in building curtain walls, metals, ceramics, plastics, doors and windows, rubber, electronic components, optical devices, rail transportation fields, and automobiles.

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