Spiropyran derivatives, color-changing glass paint, and preparation method and application thereof

Abstract

The present application relates to a kind of spiropyran derivatives, color-changing glass paint and its preparation method and application.The spiropyran derivative, characterized in that, with as shown in formula (I) structure: formula (I);In formula (I), R1, R2, R3, R4, R5 Or R6 Independently be H, OCH3 Or the specific substituent group on the specific benzene ring of this spiropyran derivative, by its skeleton and specific substituent group cooperation, can realize the color change under light condition;With the spiropyran derivative as photochromic powder, be applied in color-changing glass paint, can make color-changing glass paint color change under light condition, not only can make the light transmittance of color-changing glass paint after color change lower, and after aging treatment, still can make color-changing glass paint keep lower light transmittance, and durability is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of color-changing materials, and more particularly to a spiropyran derivative, a color-changing glass paint, and a preparation method and application thereof. BACKGROUND

[0002] With the improvement of people's living standards, various glass paint products appear in people's life, such as glass curtain walls, bay windows, glass roofs, etc., and the performance of glass paint has also been increasingly high requirements.

[0003] The color-changing glass paint usually adds color-changing materials in the liquid paint, and realizes color change under specific temperature, light and other conditions. The color-changing materials added in the color-changing glass paint usually include photochromic powder, thermochromic powder, color-changing microcapsule, color-changing fiber, etc. For example, the glass paint provided in the Chinese patent entitled "A water-based color-changing heat-insulating glass paint and a preparation method thereof" adds color-changing fiber. For the color-changing glass paint used for glass curtain walls, bay windows, glass roofs, etc., people usually pay attention to the sunlight transmittance and durability of the color-changing glass paint after color change: in addition to having a relatively suitable temperature (about 25℃) in the comfortable indoor environment, the degree of glare of sunlight needs to be reduced, and the sunlight transmittance of the color-changing glass paint after color change under normal temperature conditions is low, which can reduce the glare of sunlight shining into the indoor environment, making the indoor environment more comfortable, otherwise the sunlight shining into the indoor environment is relatively glaring, making people feel uncomfortable; durability generally refers to the color-changing glass paint after color change under normal temperature conditions, and the maintenance of the sunlight transmittance is tested after aging treatment, the better the durability, the longer the service life, and the color-changing glass does not need to be replaced frequently, reducing the use cost of the color-changing glass.

[0004] Since the photochromic powder has small particles and can be well dissolved or dispersed in the latex particles, more and more glass paints currently mainly use photochromic powder, but the color change of the existing photochromic powder after light irradiation is not obvious, resulting in high sunlight transmittance, poor effect of reducing the glare of sunlight, and poor durability, thereby limiting the application range. SUMMARY

[0005] The primary object of the present application is to overcome the problems of high transmittance and poor durability of the existing photochromic powder after color change, and to provide a spiropyran derivative. The specific benzene ring of the spiropyran derivative has a specific substituent group, and the combination of the skeleton and the specific substituent group can realize color change under light conditions. The spiropyran derivative is used as photochromic powder and applied in color-changing glass paint, which can make the color-changing glass paint change color under light conditions, not only can make the transmittance of the color-changing glass paint after color change be relatively low, but also can make the color-changing glass paint maintain a relatively low transmittance after aging treatment, and has good durability.

[0006] A further object of the present application is to provide a preparation method of the above-mentioned spiropyran derivative.

[0007] A further object of the present application is to provide the use of the above-mentioned spiropyran derivative as a photochromic material in preparing a photochromic glass paint.

[0008] A further object of the present application is to provide a photochromic glass paint.

[0009] A further object of the present application is to provide a preparation method of the above-mentioned photochromic glass paint.

[0010] A further object of the present application is to provide the use of the above-mentioned spiropyran derivative as a photochromic material in preparing a photochromic glass paint.

[0011] The above-mentioned objects of the present application are achieved by the following technical solutions.

[0012] A spiropyran derivative has the structure as shown in formula (I):

[0013]

[0014] In formula (I), R1, R2, R3, R4, R5 or R6 is independently H, OCH3 or

[0015] The specific benzene ring of the spiropyran derivative of the present application has specific substituents (H, OCH3 or ), through the cooperation of its skeleton and specific substituents, it is more sensitive to light at room temperature, and can achieve obvious discoloration under light conditions; as a photochromic powder, the spiropyran derivative can make the photochromic glass paint obviously discolored under light conditions, so that the transmittance of the discolored photochromic glass paint is low, and after aging treatment, the photochromic glass paint can still be obviously discolored, thereby maintaining a low transmittance and good durability.

[0016] Preferably, R1 is H or OCH3, R2 is OCH3 or R3 is OCH3, R4 is OCH3, R5 is OCH3 or R6 is H or OCH3.

[0017] Preferably, the spiropyran derivative is a compound having the structure as shown below:

[0018]

[0019] The preparation method of the above-mentioned spiropyran derivative comprises the following steps: addition-dehydration condensation reaction of a compound shown in formula (1) and a compound shown in formula (2), then adding methyl magnesium chloride to generate Grignard reaction, and the spiropyran derivative is obtained.

[0020]

[0021] Preferably, the molar ratio of the compound shown in formula (1) to the compound shown in formula (2) is 1:(1 to 1.2).

[0022] Preferably, the addition-dehydration condensation reaction is carried out in the presence of a catalyst, wherein the catalyst is methanesulfonic acid.

[0023] Preferably, the reaction temperature of the addition-dehydration condensation reaction is 45–60°C, and the reaction time is 30–60 min.

[0024] Preferably, the Grignard reaction is carried out at a temperature of 0–10°C and for a time of 20–30 min.

[0025] The application of the above-mentioned spiropyran derivatives as photochromic materials in the preparation of photochromic glass paint is also within the scope of protection of this invention.

[0026] A color-changing glass paint, comprising the following components in parts by weight:

[0027] 50-60 parts of polyurethane resin,

[0028] 1-2 parts of the above-mentioned spiropyran derivative,

[0029] 5-10 parts water

[0030] 15-25 parts of cosolvent.

[0031] The color-changing glass paint of the present invention incorporates spiropyran derivatives, which not only make the color change obvious under light conditions, thus reducing the light transmittance of the color-changing glass paint, but also allow the color-changing glass paint to still change significantly after aging treatment, thereby maintaining a low light transmittance and good durability.

[0032] Preferably, the polyurethane resin comprises the following raw material components in parts by weight:

[0033] Polyester polyol 8-12 parts, polyethylene glycol 3-6 parts, hexamethylene diisocyanate 1-2 parts, isophorone diisocyanate 1-3 parts, dicyclohexylmethane diisocyanate 7-9 parts, dimethylolpropionic acid 0.5-2.5 parts, trimethylolpropane 0.2-0.5 parts, neopentyl glycol 1-2 parts, triethylamine 0.5-1.5%, ethylenediamine 0.5-1 part, epoxy resin 2-6 parts, N-methylpyrrolidone 2-4 parts, water 58-65 parts.

[0034] More preferably, the polyurethane resin is prepared by the following steps: mixing the raw material components, adding an appropriate amount of catalyst, and reacting to obtain the polyurethane resin.

[0035] More preferably, the catalyst is dibutyltin dilaurate or bismuth neododecanoate.

[0036] Preferably, the color-changing glass paint further includes 10-15 parts of silicone fluoropolymer.

[0037] Adding silicone fluoropolymers can enable the color-changing glass paint to achieve self-layering, preventing spiropyran derivatives from being oxidized by contact with oxygen, thereby further reducing the light transmittance of the color-changing glass paint after color change and improving its durability.

[0038] More preferably, the silicone fluoropolymer is an organosilicon-modified fluorinated (meth)acrylic acid polymer emulsion, including but not limited to SD-5681 and FWB8999.

[0039] Preferably, the color-changing glass paint further includes 0.5 to 1 part of thermochromic powder. The addition of thermochromic powder allows the color-changing glass paint to undergo a significant color change even at higher temperatures, thus maintaining low light transmittance.

[0040] More preferably, the thermochromic powder is a material that changes from colorless to red at temperatures above 30°C.

[0041] Preferably, the co-solvent is at least one of alcohol ethers or amine solvents, including but not limited to isopropanol, N,N-dimethylformamide, etc.

[0042] Preferably, the color-changing glass paint further includes 0.1 to 1 part of other additives, including but not limited to wetting defoamers.

[0043] The preparation method of the above-mentioned color-changing glass paint includes the following steps: mixing the components to obtain the color-changing glass paint.

[0044] The application of the aforementioned photochromic glass paint in the preparation of photochromic glass is also within the scope of protection of this invention.

[0045] Preferably, the photochromic glass is curtain wall glass, bay window glass, or roof glass.

[0046] Compared with the prior art, the beneficial effects of the present invention are:

[0047] The spiropyran derivatives of the present invention have specific substituents (H, OCH3, or...) on a specific benzene ring. Through the combination of its skeleton and specific substituents, it becomes more sensitive to light at room temperature, and can achieve obvious color change under light conditions. When this spiropyran derivative is used as a photochromic powder in photochromic glass paint, it can make the photochromic glass paint change color significantly under light conditions. This not only makes the light transmittance of the photochromic glass paint low, but also allows the photochromic glass paint to still change color significantly after aging treatment, thus maintaining low light transmittance and good durability. Attached Figure Description

[0048] Figure 1 The image shows the 1H NMR spectrum of the spiropyran derivative from Synthetic Example 1. Detailed Implementation

[0049] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0050] Some of the raw materials used in the synthesis example were prepared in-house, as detailed below:

[0051] 1) 5-Hydroxy-3-methoxy-7,11b-dihydro-4aλ 5 Preparation of cyclohexano[1,2-c]fluorene-7-one:

[0052] 1.1) 21.2 g of 4-methoxybenzophenone (a) was added to a reaction flask and dissolved in 40 ml of tetrahydrofuran. The mixture was heated to 50 °C, and then 19 g of dimethyl succinate (1.3 eq) and 14.6 g of potassium tert-butoxide powder (1.3 eq) were added. The mixture was stirred vigorously for 60 min. After the reaction was confirmed to be complete by HPLC, the heating was removed, and 40 ml of water was added to quench the reaction. The reaction solution was then neutralized with dilute hydrochloric acid to pH 4. 80 ml of ethyl acetate was added to extract the reaction solution. After separation, the organic phase was washed twice with water, and the solvent was removed by rotary evaporation to obtain a yellow oily substance, which was designated as compound (b).

[0053] Compound (b) was dissolved in 190 ml of acetic anhydride, heated to 90 °C with stirring, and 60 g of triethylamine was added dropwise. The reaction was allowed to proceed for 3 h. After the reaction was confirmed to be complete, the heating was turned off, and 600 ml of water was added dropwise to the reaction solution. The mixture was stirred vigorously, and a large amount of yellowish-brown solid precipitated. The solid was filtered, the filter cake was washed with water, and the filter cake was then washed with 60 ml of methanol. After filtration, the filter cake was rinsed with a small amount of methanol and dried at 70 °C to obtain a pale yellow solid, which was designated as compound (c).

[0054] 1.2) Add 35 g of compound (c) to the reaction flask, disperse it with 140 ml of methanol, and then add an aqueous solution of sodium hydroxide (prepared by dissolving 24 g of solid sodium hydroxide in 140 ml of water). Then heat to 60 °C and react for 3 hours. After the reaction is confirmed to be complete, turn off the heating and add dilute hydrochloric acid to acidify the reaction until the pH is 3. A large amount of pale yellow solid is precipitated. Filter the solution, wash the filter cake twice with an appropriate amount of water, and dry the filter cake at 80 °C to obtain compound (d).

[0055] 1.3) Take 29.4 g of compound (d), disperse it in 100 ml of methanesulfonic acid, heat to 80 °C, and stir vigorously for 60 minutes. After the reaction is confirmed to be complete, turn off the heat and add 100 ml of water dropwise to quench the reaction. A large amount of solid will precipitate during the water addition. After the water addition is complete, continue stirring for 30 minutes, filter, and wash the filter cake with water to obtain 5-hydroxy-3-methoxy-7,11b-dihydro-4aλ. 5 -cyclohexano[1,2-c]fluorene-7-one.

[0056] The synthesis process is as follows:

[0057]

[0058] 2) Preparation of 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol:

[0059] 2.1) Add 19.7 g of 3,4,5-trimethoxybenzoic acid (1 eq) and 18.5 g of 1,2,3-trimethoxyphenyl (1.1 eq) to a reaction flask, then add 120 mL of Eaton reagent, heat to 70 °C, and react for 6 h with vigorous stirring. After the reaction is complete as detected by HPLC, turn off the heating and allow the temperature of the reaction solution to drop to about 50 °C. Then slowly add 240 mL of water to the reaction solution, and allow it to cool naturally with vigorous stirring to crystallize. Filter, wash the filter cake twice with water, and dry to obtain the target product bis(3,4,5-trimethoxyphenyl) ketone.

[0060] 2.2) Add 80 ml of tetrahydrofuran to the reaction flask, and lower the temperature to below -50°C using a dry ice ethanol bath. Then, add 40 ml of butyllithium in n-hexane (2.52 mol / L), and slowly introduce 0.1 mol of acetylene gas into the reaction flask to prepare lithium acetylenide. Then, add bis(3,4,5-trimethoxyphenyl) ketone to the reaction solution, remove the dry ice ethanol bath, and slowly raise the temperature to room temperature. After about 3 hours of reaction, check that the reaction is complete, slowly add 120 ml of water to the reaction solution, allow it to stand and separate, wash with water until a large amount of white solid precipitates, filter, wash the filter cake with water, and dry at 80°C to obtain the compound. Replacing other substrates can yield the corresponding target alkynol compound.

[0061] 3) Preparation of 1-(3,4,5-trimethoxyphenyl)-1-(3,4-dimethoxyphenyl)prop-2-yn-1-ol, 1,1-bis(3,4-dimethoxyphenyl)prop-2-yn-1-ol, and 1,1-bis(3-methoxy-4-piperidinephenyl)prop-2-yn-1-ol: The preparation methods are basically the same as those for 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol, with the main difference being that the raw material 3,4,5-trimethoxybenzoic acid or 1,2,3-trimethoxybenzene in step 2.1) is replaced with a raw material with a corresponding substituent at the benzene ring position (such as 3,4-dimethoxybenzoic acid, 1,2-dimethoxybenzene, etc.).

[0062] All other raw materials or reagents not specifically mentioned are commercially available.

[0063] Synthesis example 1

[0064] This synthetic example provides a spiropyran derivative, the preparation method of which includes the following steps:

[0065] 1.1 276 g of 5-hydroxy-3-methoxy-7,11b-dihydro-4aλ 5 Cyclohexano[1,2-c]fluorene-7-one and 465 g of 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol were added to a reaction flask (the molar ratio of the two was 1:1.2). The mixed raw materials were dispersed in 1380 mL of tetrahydrofuran (THF) solvent (the raw materials would not dissolve completely, presenting a solid-liquid two-phase mixture). With stirring, 0.01 equivalent of methanesulfonic acid was added dropwise. The reaction system was then heated to 60 °C. After reacting for 30 min, a sample was taken to check that the reaction was basically complete. Heating was stopped, and 4 L of methanol was added for crystallization. After a large amount of solid precipitated, the solid was filtered out using a sintered glass funnel. The filter cake was washed once with methanol and then dried at 70 °C to obtain a red powdery solid with a yield of about 80%.

[0066] 1.2 Add 323 g of the red powdery solid (M3 = 646.22) obtained in step 1.1 to a reaction flask, disperse it with 1.5 L of tetrahydrofuran (THF) by stirring, cool it in an ice bath, and when the temperature of the reaction solution is below 5°C, start adding a 1.5 L (3 eq) THF solution of methyl magnesium chloride (3 M / L) to the reaction solution. Keep the reaction temperature not higher than 10°C. After the addition is complete, continue stirring for 30 min. After the substrate reaction is complete, add an appropriate amount of water to the reaction solution to quench the reaction, then neutralize with dilute hydrochloric acid, extract with ethyl acetate, wash with water, evaporate most of the solvent, add methanol to crystallize, and obtain the spiropyran derivative, denoted as spiropyran derivative 1#.

[0067] from Figure 1According to the NMR information, the spiropyran derivative of this synthesis example was successfully synthesized, and its structural formula is as follows:

[0068]

[0069] Synthesis example 2

[0070] This synthetic example provides a spiropyran derivative, which is prepared in a manner basically the same as that of Synthetic Example 1, except that 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol in step 1.1 is replaced with 1-(3,4,5-trimethoxyphenyl)-1-(3,4-dimethoxyphenyl)prop-2-yn-1-ol, and finally the spiropyran derivative is obtained, denoted as spiropyran derivative 2#.

[0071] The starting material 1-(3,4,5-trimethoxyphenyl)-1-(3,4-dimethoxyphenyl)prop-2-ynthin-1-ol in this synthesis example has very similar properties to the starting material in Synthesis Example 1, so no corresponding characterization was performed. However, this did not affect the progress of the reaction or the acquisition of the target product. The structural formula of the obtained spiropyran derivative is as follows:

[0072]

[0073] Synthesis example 3

[0074] This synthetic example provides a spiropyran derivative, which is prepared in a manner that is basically the same as that of synthetic example 1, except that 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol in step 1.1 is replaced with 1,1-bis(3,4-dimethoxyphenyl)prop-2-yn-1-ol, and finally the spiropyran derivative is obtained, which is denoted as spiropyran derivative 3#.

[0075] The starting material 1,1-bis(3,4-dimethoxyphenyl)prop-2-ynthin-1-ol used in this synthesis example has properties very similar to those of the starting material in Synthesis Example 1, so no corresponding characterization was performed. However, this did not affect the progress of the reaction or the acquisition of the target product. The structural formula of the obtained spiropyran derivative is as follows:

[0076]

[0077] Synthesis example 4

[0078] This synthetic example provides a spiropyran derivative, which is prepared in a manner that is basically the same as that of synthetic example 1, except that 1,1-bis(3,4,5-trimethoxyphenyl)prop-2-yn-1-ol in step 1.1 is replaced with 1,1-bis(3-methoxy-4-piperidinphenyl)prop-2-yn-1-ol, and finally the spiropyran derivative is obtained, which is denoted as spiropyran derivative 4#.

[0079] The starting material 1,1-bis(3-methoxy-4-piperidinylphenyl)prop-2-ynthin-1-ol used in this synthesis example has properties very similar to those of the starting material in Synthesis Example 1, so no corresponding characterization was performed. However, this did not affect the progress of the reaction or the acquisition of the target product. The structural formula of the obtained spiropyran derivative is as follows:

[0080]

[0081] The polyurethane resins used in the embodiments and comparative examples of this invention were prepared in-house, as detailed below:

[0082] Polyurethane Resin 1#: A mixed solution of 12 parts by weight of polyester polyol, 3 parts of polyethylene glycol, 1 part of hexamethylene diisocyanate, 3 parts of isophorone diisocyanate, and 8 parts of dicyclohexylmethane diisocyanate was added to a three-necked flask equipped with a condenser, thermometer, separatory funnel, and stirrer. A mixed solution of dimethylolpropionic acid (0.5 parts), trimethylolpropane (0.5 parts), and N-methylpyrrolidone (4 parts) was added dropwise at 70°C with stirring. After stirring for 45 min, neopentyl glycol (1 part), epoxy resin (2 parts), and an appropriate amount of catalyst dissolved in acetone were added dropwise to the three-necked flask. The mixture was stirred at 80°C for 3 h. After cooling to 60°C, a mixed solution of triethylamine (0.5 parts) and ethylenediamine (1 part) was added. The mixture was stirred for 15 min and cooled to room temperature. After emulsification with water, excess acetone was removed by vacuum distillation to obtain polyurethane resin 1#.

[0083] Polyurethane Resin 2#: The preparation process is basically the same as that of Polyurethane Resin 1#, except for the following: the amount of each raw material component: 10 parts polyester polyol, 5 parts polyethylene glycol, 2 parts hexamethylene diisocyanate, 1 part isophorone diisocyanate and 7 parts dicyclohexylmethane diisocyanate, 1.5 parts dimethylolpropionic acid, 0.3 parts trimethylolpropane, 3 parts N-methylpyrrolidone, 1.5 parts neopentyl glycol, 4 parts epoxy resin, 1 part triethylamine and 1 part ethylenediamine.

[0084] Polyurethane Resin 3#: The preparation process is basically the same as that of Polyurethane Resin 1#, except for the following: the amount of each raw material component: 8 parts polyester polyol, 6 parts polyethylene glycol, 1 part hexamethylene diisocyanate, 2 parts isophorone diisocyanate and 9 parts dicyclohexylmethane diisocyanate, 2.5 parts dimethylolpropionic acid, 0.1 parts trimethylolpropane, 2 parts N-methylpyrrolidone, 2 parts neopentyl glycol, 6 parts epoxy resin, 1.5 parts triethylamine and 0.5 parts ethylenediamine.

[0085] Examples 1-8

[0086] Examples 1-8 provide a series of color-changing glass paints, the formulations of which are shown in Table 1.

[0087] Table 1. Formulations (parts by weight) of the color-changing glass paints in Examples 1-8

[0088]

[0089]

[0090] In Table 1, the silicone-fluorine resin used is organosilicon-modified fluorinated (meth)acrylic acid polymer emulsion; the wetting defoamer used is Evonik SURFYNOL 104E; and the thermochromic powder used is Lijin Technology BS-6594.

[0091] The preparation methods of the color-changing glass paint in Examples 1-8 are as follows: Isopropanol, N,N-dimethylformamide, wetting and defoaming agent, thermochromic powder (if any) and spiropyran derivative are added sequentially to a container and dispersed and dissolved for 15 minutes at a stirring rate of 2000 rpm to obtain component A; component A and water are added sequentially to polyurethane resin at a stirring rate of 3000 rpm and dispersed for 15 minutes to obtain component B; silicone fluoropolymer is added to component B at a stirring rate of 2000 rpm and dispersed for 15 minutes to obtain the color-changing glass paint; in Example 7, silicone fluoropolymer is not added, so component B obtained in Example 7 is the color-changing glass paint.

[0092] Comparative Example 1

[0093] This comparative example provides a color-changing glass paint, the preparation method and formula of which are basically the same as those in Example 3, except that the spiropyran derivative 1# is replaced with commercially available photochromic powder (brand name Green A, manufacturer: Shanghai Anyi New Trading Co., Ltd.).

[0094] Comparative Example 2

[0095] This comparative example provides a color-changing glass paint, the preparation method and formula of which are basically the same as those in Example 3, except that spiropyran derivative 1# is not added.

[0096] Performance testing

[0097] The performance of the color-changing glass paints in each embodiment and comparative example was tested, and the test results are shown in Table 2.

[0098] Table 2 shows the performance test results of the color-changing glass paints in each embodiment and comparative example.

[0099]

[0100]

[0101] As can be seen from Table 2:

[0102] The adhesion performance of the color-changing glass paints in Examples 1 to 8 is all grade 0. Under normal temperature (24℃) conditions, the color change is obvious under light, resulting in a light transmittance of less than 35%. Furthermore, the color-changing glass paints in Examples 3 to 6 can still change color significantly under light after aging treatment (GB / T 1865-2009), resulting in a still low light transmittance. This indicates that the color-changing glass paint of the present invention has good adhesion, is sensitive to light at room temperature, has low light transmittance after color change, and has good durability.

[0103] Comparative Example 1 used commercially available photochromic powder, which showed minimal color change after light exposure, high light transmittance, and difficulty in reducing the glare of sunlight. Further comparison with Examples 3-6 showed that, under normal temperature (24°C) conditions, the photochromic glass paint in Comparative Example 1, after aging treatment, exhibited even less noticeable color change after light exposure, with a 6% increase in light transmittance. This indicates that the durability of existing photochromic powders is inferior to the spiropyran derivative of this invention. Comparative Example 2 did not contain photochromic powder, and its color change after light exposure was minimal, while its light transmittance was significantly high.

[0104] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A color-changing glass paint, characterized in that, The components include the following parts by weight: 50-60 parts of polyurethane resin, 1-2 parts of spiropyran derivative, 5-10 parts water 15-25 parts of cosolvent 10-15 parts of silicone fluoropolymer; The spiropyran derivative is a compound with the following structure: , .

2. The color-changing glass paint according to claim 1, characterized in that, The preparation method of the spiropyran derivative includes the following steps: the compound shown in formula (1) undergoes an addition-dehydration condensation reaction with the compound shown in formula (2), and then methyl magnesium chloride is added to undergo a Grignard reaction to obtain the spiropyran derivative. Equation (1) Equation (2); R1, R2, R3, R4, R5, and R6 are all OCH3, or R1 is H and R2, R3, R4, R5, and R6 are all OCH3.

3. The color-changing glass paint according to claim 1, characterized in that, The polyurethane resin comprises the following raw material components in parts by weight: Polyester polyol 8-12 parts, polyethylene glycol 3-6 parts, hexamethylene diisocyanate 1-2 parts, isophorone diisocyanate 1-3 parts, dicyclohexylmethane diisocyanate 7-9 parts, dimethylolpropionic acid 0.5-2.5 parts, trimethylolpropane 0.2-0.5 parts, neopentyl glycol 1-2 parts, triethylamine 0.5-1.5%, ethylenediamine 0.5-1 part, epoxy resin 2-6 parts, N-methylpyrrolidone 2-4 parts, water 58-65 parts.

4. The color-changing glass paint according to claim 1, characterized in that, The color-changing glass paint also includes 0.5 to 1 part of thermochromic powder.

5. The method for preparing the color-changing glass paint according to any one of claims 1 to 4, characterized in that, The process includes the following steps: mixing the components to obtain the color-changing glass paint.

6. The use of the photochromic glass paint according to any one of claims 1 to 4 in the preparation of photochromic glass.

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