CN107779072B

CN107779072B - Photochromic coating liquid and application thereof

Info

Publication number: CN107779072B
Application number: CN201711110839.0A
Authority: CN
Inventors: 王明华; 张鹤军; 范为正; 纪立军; 乔振安; 司云凤; 王志飞; 郑永华; 薛晓花; 吴潇; 刘洋
Original assignee: Jiangsu Shike New Material Co ltd
Current assignee: Jiangsu Shike New Material Co ltd
Priority date: 2017-11-10
Filing date: 2017-11-10
Publication date: 2020-08-25
Anticipated expiration: 2037-11-10
Also published as: CN107779072A

Abstract

The coating liquid contains a polyurethane/spiropyran/zinc sulfide composite multilayer photochromic material, wherein the inner core of the coating liquid is a zinc sulfide mesoporous nano microsphere, the middle layer is a photochromic layer formed by spiropyran compounds, and the shell is polyurethane; the composite microsphere has the outer diameter of 50-350nm, wherein the diameter of the zinc sulfide mesoporous nano microsphere is 30-250 nm, the thickness of the middle layer is 5-25 nm, and the thickness of the shell is 5-25 nm. The coating liquid can be used for preparing photochromic coatings, the coatings can be changed into colors from colorless under the irradiation of ultraviolet rays, and the coatings can be quickly faded into colorless after the ultraviolet rays disappear, and the photochromic coatings have the advantages of strong fatigue resistance, good stability, high color changing speed and the like.

Description

Photochromic coating liquid and application thereof

Technical Field

The invention belongs to the technical field of photochromism, and particularly relates to an optical material color-changing coating liquid containing photochromism nano composite microspheres and application thereof.

Background

Photochromic refers to a functional material which is a compound, under the action of light with certain wavelength and intensity, and the molecular structure of the material is changed along with the change of an absorption spectrum, so that the absorbance and the color of the material are changed, the change is generally reversible, and the material can automatically recover to the original state after the light is stopped, and the photochromic material is used as a new material in the field of optical material subdivision and has important application value in the technical fields of optical lenses, optical information storage, molecular switches, anti-counterfeiting identification and the like. The phenomenon of photochromism has been found by humans for over a hundred years. The first successful commercial application, starting in the 60's of the 20 th century, two materials scientists, amistod and Stooky, in the Corning studio of the united states, first prepared photochromic materials containing silver halide glasses, and then a great deal of research into their mechanisms and applications, and the development of new photochromic eyewear. However, due to its high cost and complex processing technology, it is not suitable for manufacturing large-area photochromic glass, and thus, its commercial application in the building field is limited. Then, the application center of gravity of photochromism is shifted to polymer-based materials with low price and light weight, and the photochromism compound is added into transparent resin to prepare the photochromic material which can be used for resin spectacle lenses and is applied to photochromic spectacles at home and abroad. Silver halide photochromic materials have been phased out because they are not suitable for use with resin lenses. The application of the organic photochromic compound on the resin lens at present mainly comprises the following types: spiroindoline naphthoxazines, naphthopyrans, fulgide photochromic compounds, and the like. Although important achievements are achieved in the aspect of practical application, the disadvantages of poor light stability, low photochromic response value, insufficient thermal stability and the like of the photochromic compound exist, such as: photochromic compounds are susceptible to the influences of pH value, oxidation, illumination intensity, temperature, matrix environment and the like to cause the deterioration of photochemical fatigue, and are degraded and deteriorated after repeated irradiation for many times to lose reversible photochromic performance, or the conditions of prolonged color change response time, reduced chromaticity, delayed fading recovery time and the like are caused.

The light stability, namely fatigue resistance, of the color-changing compound is one of the important problems of the color-changing compound in practical application. The research on photochromic mechanism shows that the main reason for fatigue is that the compound is photooxidation degraded during the photoisomerization reaction, and the fatigue phenomenon occurs. Therefore, antioxidant research has become a major approach for compounds to improve fatigue resistance. At present, the following methods are mainly utilized to improve the fatigue resistance: firstly, adding a light stabilizer or an antioxidant into a polymer medium containing a color-changing compound; secondly, directly keying antioxidant groups on compound molecules; thirdly, introducing an electricity-rich heteroaryl group into a side chain of a compound molecule; and fourthly, improving the fatigue resistance by adding a single-base peroxy quencher or adopting a spin-trapping agent. Therefore, researchers have improved performance by microencapsulating color-changing compounds, such as: patent ZL200810057392 discloses a preparation method of photochromic microcapsules, which can improve the acid and alkali resistance and fatigue resistance of photochromic materials and prolong the service life. The patent ZL201410195430.3 discloses a preparation method of a polyurethane-chitosan double-shell photochromic microcapsule, and double-layer coating can further improve the coating rate, fatigue resistance and the like of photochromic compounds. Therefore, the development of compounds and composite materials with good photochromic performance has become one of the research hotspots of photochromic materials in recent years, and particularly, the development of the photochromic materials with excellent fatigue resistance, good thermal stability and high spectral response value has higher popularization and application values.

In addition, photochromic properties are also often affected by the polymer molecules, other chemical aids in the matrix, the microstructure, the polymerization environment, etc., such as: the color-changing compound is greatly influenced by the ultraviolet absorbent in the polymer, and the color-changing compound is greatly limited by the excitation of ultraviolet spectrum to change color due to the absorption of ultraviolet rays by the ultraviolet absorbent in the polymer, so that the color-changing efficiency is low; meanwhile, the existence of diopter leads to the inconsistency of the edge thickness and the center thickness of the lens, in this case, if the method of adding the color-changing compound in the body is still adopted, the color depth chromatic aberration of different positions of the thickness of the lens can be caused. Therefore, some manufacturers in China use spin coating to produce color-changing lenses. The spin coating method is that after the substrate is made, the prepared color-changing solution is added into a groove of a spin coater, after the color-changing solution is fully mixed, the substrate is fixed on the spin coater to carry out centrifugal rotation movement, and the substrate is solidified to form a product with the color-changing effect.

Disclosure of Invention

The invention aims to provide photochromic coating liquid and application thereof, wherein the coating liquid contains a polyurethane/spiropyran/zinc sulfide composite multilayer photochromic material and can be used for preparing a photochromic coating, the coating can be changed into color from colorless under the irradiation of ultraviolet rays, and the coating can be quickly faded into colorless after the ultraviolet rays disappear, and the photochromic coating liquid has the advantages of strong fatigue resistance, good stability, high color changing speed and the like.

In order to achieve the purpose, the invention provides the following technical scheme:

a photochromic coating liquid contains polyurethane/spiropyran/zinc sulfide photochromic composite microspheres, wherein the photochromic composite microspheres are of a three-layer composite core-shell structure, the inner core of the photochromic composite microspheres is zinc sulfide mesoporous nano microspheres, the middle layer of the photochromic composite microspheres is a photochromic layer formed by spiropyran compounds, and the outer shell of the photochromic composite microspheres is polyurethane; the composite microsphere has the outer diameter of 50-350nm, wherein the diameter of the zinc sulfide mesoporous nano microsphere is 30-250 nm, the thickness of the middle layer is 5-25 nm, and the thickness of the shell is 5-25 nm.

In the photochromic coating solution, preferably, the zinc sulfide mesoporous nanospheres are monodisperse zinc sulfide mesoporous nanospheres composed of zinc sulfide nanocrystals, and the intermediate layer is formed by uniformly dispersing spiropyran compound nanoparticles on the surface or in gaps of the zinc sulfide mesoporous nanospheres to form a nanocomposite mesoporous structure.

Preferably, the spiropyran-based compound is selected from the group consisting of compounds of formula (I), formula (II) and formula (III):

wherein R ═ C₁₆H₃₃

Wherein R ═ C₁₆H₃₃

In the photochromic coating liquid, the polyurethane is preferably obtained by polymerizing an isocyanate monomer compound containing two or more isocyanate groups and an alcohol compound.

The photochromic coating solution as described above, preferably, the isocyanate monomer compound is selected from: at least one of toluene diisocyanate, diphenylmethane-4, 4' -diisocyanate, 1, 6-hexamethylene diisocyanate, m-xylylene diisocyanate, naphthalene-1, 5-diisocyanate, methylcyclohexyl diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, and isophorone diisocyanate;

preferably, the alcohol compound is at least one of n-butanol, polytetrahydrofuran ether glycol, pentaerythritol, ethylene glycol), propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, and trimethylolpropane.

The photochromic coating liquid preferably comprises a component A and a component B in parts by weight as follows:

(1) a component A:

(2) b, component B:

isocyanate type curing agent 12-17

Catalyst 0-1

0-1 part of defoaming agent.

In the photochromic coating solution, the polythiourethane monomer is preferably at least one of 2, 2 '-dimercaptoethylsulfide, 2' -dimercaptoethylthioethane, 2, 3-dimercaptoethylthiopropanethiol, or 1, 2, 3-trimercaptoethylthiopropane;

preferably, the isocyanate-based curing agent is at least one of a toluene diisocyanate curing agent, a diphenylmethane-4, 4' -diisocyanate curing agent, a 1, 6-hexamethylene diisocyanate curing agent, an m-xylylene diisocyanate curing agent, a methylcyclohexyl diisocyanate curing agent, and an isophorone diisocyanate curing agent;

preferably, the catalyst is dibutyltin dilaurate.

The photochromic coating solution as described above, preferably, the diluent is at least one of dichloromethane, butyl acetate, methyl acetate, ethanol, butanol, acetone, toluene, xylene, diethyl ether and polytetrahydrofuran ether glycol;

preferably, the wetting dispersant is a BYK polyurethane type special wetting dispersant or an F420 type wetting dispersant;

preferably, the leveling agent is an oily F300 type leveling agent, an F309 type leveling agent or an F320 type leveling agent;

preferably, the defoaming agent is XPJ01 type modified silicone oil defoaming agent 01F.

In another aspect, the present invention provides a method for preparing the photochromic coating fluid, comprising the following steps:

(1) a component A: adding the polythiourethane monomer, the diluent, the polyurethane/spiropyran/zinc sulfide photochromic composite microspheres, the wetting dispersant and the flatting agent into a container according to the proportion, and uniformly stirring for 15-30 minutes at room temperature to obtain a component A;

(2) b, component B: adding the isocyanate curing agent, the defoaming agent and the catalyst into a container according to the proportion, and uniformly stirring for 3-5 minutes at room temperature to obtain the component B.

In still another aspect, the present invention includes using the photochromic coating liquid as described above for preparing a photochromic coating layer of an optical substrate, preferably, mixing the component a and the component b and coating them on the surface of the optical substrate to form a coating layer, and then curing them by light irradiation or heating to prepare the photochromic coating layer.

The polyurethane/spiropyran/zinc sulfide photochromic nano composite microsphere can be prepared by the following method:

a. preparing spiropyran coated zinc sulfide nanospheres:

adding zinc nitrate into ethylene glycol, uniformly stirring, adding sulfur powder, heating to the temperature of 140 ℃ and 160 ℃, and reacting for 20-24 hours; cooling to 40-60 ℃, dropwise adding a mercaptoethanol stabilizer and stirring; adding a spiropyran compound, stirring vigorously for 20-40 minutes, cooling to room temperature, gradually layering and precipitating reaction liquid, filtering and collecting precipitate, washing, and drying to obtain spiropyran-coated zinc sulfide mesoporous nanospheres; wherein the mass ratio of the zinc nitrate, the sulfur powder, the mercaptoethanol and the ethylene glycol is (0.3-0.6) to (0.1-0.2) to (4-7) to (90-110), and the mass ratio of the zinc nitrate and the spiropyran compound is 1 to (0.5-1);

b. preparing polyurethane/spiropyran/zinc sulfide nano composite microspheres:

b, adding the spiropyran coated zinc sulfide mesoporous nanospheres and the isocyanate monomer compound prepared in the step a into a solvent, uniformly stirring, and then sequentially adding an alcohol compound and a dispersing agent; wherein the spiropyran-coated zinc sulfide mesoporous nanospheres, the isocyanate monomer compound, the alcohol compound, the dispersant and the solvent are in mass ratio as follows: (0.5-1.2) to (0.5-0.9) to (1.2-2.2) to 100; keeping the temperature at 15-25 ℃, and carrying out prepolymerization reaction for 45-60min under stirring to obtain a prepolymer solution; adding a chain extender and a catalyst into a prepolymer solution, heating the chain extender, the catalyst and an isocyanate monomer compound to the mass ratio of (6-15) to (0.1-0.3) to (9-11) to perform polymerization chain extension reaction for 10-15min under the stirring condition at the temperature of 45-90 ℃, generating a polyurethane coating precipitate, filtering, washing and drying the precipitate to obtain the photochromic nano composite microsphere with the polyurethane/spiropyran/zinc sulfide three-layer composite core-shell structure.

In the above method for preparing photochromic nanocomposite microspheres, the alcohol compound is preferably a mixture of n-butanol and polytetrahydrofuran ether glycol, wherein the mass ratio of n-butanol to polytetrahydrofuran ether glycol is (1-3) to (9-11).

In the preparation method of the photochromic nanocomposite microsphere, the solvent is preferably at least one of chloroform, acetone, propyl acetate, butyl acetate, ethyl acetate, dibutyl phthalate and petroleum ether.

In the preparation method of the photochromic nano composite microspheres, the catalyst is dibutyltin dilaurate.

In the preparation method of the photochromic nanocomposite microsphere, preferably, the dispersant is at least one of tween 20, tween80, span 20, span 60 and span 80.

In the preparation method of the photochromic nanocomposite microsphere, the chain extender is preferably at least one of ethylene glycol, propylene glycol, ethylenediamine, propylenediamine and diethylamine.

In the preparation method of the photochromic nanocomposite microsphere, the chain extender is preferably a mixture of ethylene glycol and ethylenediamine, and the mass ratio of the ethylene glycol to the ethylenediamine is (2-3) to (0.6-1.5).

The spiropyran photochromic compound of the present invention may be any known spiropyran photochromic compound, preferably spiropyran photochromic compound (I), spiropyran photochromic compound (II), spiropyran photochromic compound (III), and the three compounds may be synthesized by, but not limited to, the following methods.

(1) Synthesis of spiropyran photochromic Compound (I):

I. adding 2, 3, 3-trimethylindole and iodohexadecane into a trichloromethane solvent with a reflux device, wherein the mass ratio of the 2, 3, 3-trimethylindole to the iodohexadecane to the trichloromethane is (25-35) to (80-110) to (350-400), heating and refluxing for 16-24 hours under normal pressure, evaporating to remove the solvent, adding anhydrous ether, namely, generating a large amount of light yellow solids, performing suction filtration, fully washing with ether, and performing vacuum drying to obtain hexadecane-2, 3, 3-trimethylindole (PS 01);

dispersing PS01 in water, wherein the mass ratio of water to iodohexadecane is (1-2) to 1, continuously stirring and dropwise adding 25-35% NaOH solution until the solid completely disappears, stopping dropwise adding until a yellowish oily viscous substance is generated on the liquid surface, clarifying the lower layer, extracting with diethyl ether, washing with water, filtering, and removing diethyl ether by rotary evaporation to obtain a yellowish transparent liquid 3, 3-dimethyl-1' -hexadecyl-2-methylindole (PS 02);

preparing an ethanol solution containing PS02 and an ethanol solution containing 4-hydroxy-1, 3-benzenedicarboxaldehyde respectively, wherein the mass ratio of PS02 to ethanol is (1-2) to (3-9), and the mass ratio of PS02 to 4-hydroxy-1, 3-benzenedicarboxaldehyde is (2-3) to 1, 4-hydroxy-1, 3-benzenedicarboxaldehyde to ethanol is (2-3) to (50-100); heating the 4-hydroxy-1, 3-benzene dicarbaldehyde ethanol solution in an oil bath at 45-78 ℃ under the protection of nitrogen until reflux, dropwise adding a newly prepared ethanol solution containing PS02 into the ethanol solution, wherein the reaction solution quickly becomes purple, continuously heating and refluxing for 5-6 hours, cooling the room temperature, pouring the reaction solution into ice, stirring to obtain a light purple emulsion, fully standing, evaporating water and ethanol, recrystallizing a sticky substance with methanol, and performing suction filtration and drying to obtain light purple solid powder, namely the alkyl spiropyran photochromic compound (I).

The specific reaction formula is as follows:

(2) synthesis of spiropyran photochromic Compound (II):

dissolving 2-hydroxy-1-naphthaldehyde in absolute ethyl alcohol according to the mass ratio of (0.8-1.2) to (15-30), heating to 45-78 ℃ under the protection of nitrogen, refluxing, dropwise adding an ethanol solution containing PS02, wherein the mass ratio of the PS02 ethanol solution to the 2-hydroxy-1-naphthaldehyde is (2-3) to 1, wherein the mass ratio of PS02 to absolute ethyl alcohol is (1-2) to (3-9), continuously and stably refluxing for 8-10h, cooling to room temperature, concentrating the solvent to 40-50%, sealing, placing in ice bath at 0-minus 5 deg.C for 10-20 h, separating out a large amount of white solid, performing suction filtration, performing column chromatography (petroleum ether: ethyl acetate 1: 1 elution) on a crude product, and performing vacuum drying to obtain the alkyl-naphthalene ring spiropyran photochromic compound (II), wherein the specific reaction formula is as follows:

(3) synthesis of spiropyran photochromic Compound (III):

the first step is as follows: heating 4-hydroxy-6, 7-dimethoxy-1-phenyl-2-naphthoic acid, o-xylene and polyphosphoric acid to 160 ℃ at the mass ratio of (0.8-1.2) to (1.5-2.5) to (0.8-1.2) for reaction for 1-2H, pouring the reaction liquid into water for filtration, and performing vacuum drying to obtain 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ] fluorene-7-ketone;

the second step is that: reacting tetrahydrofuran with 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ]]Mixing fluorene-7-ketone in the weight ratio of 0.6-1 to 1, cooling to-10-20 deg.c, and dropping methyl magnesium chloride in the concentration of 3.0M, methyl magnesium chloride and 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ]]The mass ratio of the fluorene-7-ketone is (0.6-1.2) to (0.7-1.2), and the temperature is controlled not to exceed-10 ℃ in the dropping process. After the dropwise addition is finished, the temperature is kept between minus 10 ℃ and minus 15 ℃ for reaction for 90 to 120 minutes, saturated ammonium chloride solution is added for quenching reaction, the mass ratio of ammonium chloride to methyl magnesium chloride is (1-3) to 1, liquid separation is carried out, an aqueous layer is extracted by ethyl acetate, organic layers are combined, and anhydrous Na₂SO₄Drying, vacuum evaporating solvent, and performing column chromatography to obtain 2, 3-dimethoxy-7-methyl-7H-benzo [ c ]]Fluorene-5, 7-diol;

the third step: 2, 3-dimethoxy-7-methyl-7H-benzo [ c ]]Fluorene-5, 7-diol, toluene, 1-di (4-methoxyphenyl) -2-propyn-1-ol and p-toluenesulfonic acid (TsOH) according to the mass ratio: mixing (0.7-1.0) to (4-6) to (0.6-1.0) to (0.1-0.3), heating to 65-95 deg.C for 10-16h, vacuum evaporating toluene, adding saturated sodium bicarbonate solution for quenching reaction, mixing sodium bicarbonate solution and p-toluene at a mass ratio of (0.3-0.6) to 1, separating, extracting with ethyl acetate in water layer, mixing organic layers, and adding anhydrous Na₂SO₄Drying, vacuum evaporating solvent, and column chromatography (petroleum ether: ethyl acetate 15: 1 elution) is carried out on the crude product to obtain the spiropyran photochromic compound (III).

The main reaction process is that 4-hydroxy-6, 7-dimethoxy-1-phenyl-2-naphthoic acid is cyclized under the acid condition to obtain an intermediate 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ] fluorene-7-ketone; and reacting with methyl Grignard reagent-magnesium chloride to obtain 2, 3-dimethoxy-7-methyl-7H-benzo [ c ] fluorene-5, 7-diol; then the spiropyran photochromic compound (III) is generated by the reaction of the spiropyran photochromic compound (III) and 1, 1-di (4-methoxyphenyl) -2-propyne-1-alcohol under the catalysis of p-toluenesulfonic acid, and the specific reaction formula is as follows:

the acid in the reaction is acetic acid, trifluoroacetic acid, phosphoric acid, sulfuric acid or polyphosphoric acid, preferably polyphosphoric acid.

The photochromic nano composite microsphere of polyurethane/spiropyran/zinc sulfide contained in the photochromic coating liquid is of a three-layer composite core-shell structure, the inner core of the photochromic nano composite microsphere is a mesoporous nano microsphere of zinc sulfide, and in the preferred technical scheme of the invention, the preparation route of the mesoporous nano microsphere of zinc sulfide is as follows: condensing ethylene glycol at high temperature to produce acetaldehyde, providing a hydrogen atom, and using the acetaldehyde as a reducing agent to change S into S^2-Followed by release of Zn from zinc nitrate hexahydrate²⁺And S^2-Combining to form ZnS crystal nucleus which grows continuously based on a diffusion mechanism, so that initial particles of the reaction, namely zinc sulfide nanocrystals are gradually aggregated to form secondary particles, namely zinc sulfide nanospheres; when nucleation reaches a certain stage, mercaptoethanol plays an important role in the reaction process, on one hand, the mercaptoethanol effectively prevents the agglomeration of a large number of particles, on the other hand, the continuous growth of the particles is limited, and the nucleation of the nanocrystals is gradually stopped along with the reduction of the ion concentration, wherein the specific nucleation reaction equation is as follows:

HOCH₂CH₂OH→CH₃CHO+H₂O (1)

S+2CH₃CHO→CH₃CO-OCCH₃+S^2-+2H⁺(2)

Zn²⁺+S^2-→ZnS(s) (3)

the prepared zinc sulfide nano microsphere is formed in the nucleation process of zinc sulfide nano crystals, and is a monodisperse zinc sulfide mesoporous nanosphere consisting of a plurality of small nano crystals.

And the added spiropyran discoloring compound is uniformly dispersed on the surface and gaps of the zinc sulfide microspheres in a nanoparticle form. And finally, covering by using polyurethane as a shell to form the nano composite core-shell structure.

As shown in fig. 7, the photochromic nanocomposite microspheres are spherical in appearance, wherein the darker core is composed of a plurality of uniformly sized and monodisperse zinc sulfide nanospheres, the lighter colored outer layer is a spiropyran chromic compound, and the outer shell of polyurethane is a colorless transparent material, so that the photochromic nanocomposite microspheres cannot be displayed and distinguished in a transmission electron microscope photograph.

The invention has the beneficial effects that: the photochromic coating liquid contains photochromic nano composite microspheres of a polyurethane/spiropyran/zinc sulfide three-layer composite core-shell structure, the spiropyran serving as a photochromic compound is positioned between a shell and a core, namely a middle layer, the three-dimensional space is in a nanoscale range, and the energy level change and the energy gap widening caused by quantum size effect are realized. On one hand, the unique structure can ensure that the color-changing compound is protected by a polyurethane shell with relatively stable property, and the color-changing compound is prevented from being influenced by the external environment; on the other hand, due to the stable supporting effect of the core zinc sulfide nano mesoporous structure, the Van der Waals area of the color-changing molecules is enlarged, the conjugated system is enlarged, the space volume of the molecules is enlarged, and the gaps between the molecules are enlarged, so that the space for the molecules to generate isomerization reaction is greatly increased, the activity of the color-changing body is enhanced, the obstruction of conversion between the color-changing open ring body and the colorless closed ring body is reduced, the conversion time is shortened, the speed is accelerated, the spectral response becomes more sensitive, and the color-changing effect is good. In addition, under the illumination condition, the polyurethane shell can absorb part of light, part of incident ultraviolet rays are absorbed by the zinc sulfide core, and the light intensity irradiated on the surface of the spiropyran allochroic compound is lower than that directly irradiated on the surface of the spiropyran allochroic compound; meanwhile, the irradiation intensity and the irradiation retention time required for exciting the color change of the spiropyran are not influenced, and the residual ultraviolet rays are absorbed by the zinc sulfide inner core. Therefore, the oxidation resistance and fatigue resistance of the polyurethane/spiropyran/zinc sulfide nano composite microsphere are obviously enhanced.

The photochromic coating liquid is composed of two components, and when the photochromic coating liquid is used, the two components are mixed and the viscosity is adjusted, the mixture is coated on the surface of an optical substrate to form a coating layer, and then the coating layer is solidified by light irradiation or heating, thereby preparing the photochromic coating. The photochromic coating can be changed into color from colorless under the irradiation of ultraviolet rays, and can be quickly faded into colorless after the ultraviolet rays disappear, and the photochromic coating has the advantages of strong fatigue resistance, good stability, high color changing speed and the like.

Drawings

FIG. 1 is a normal environment absorption spectrum of the polyurethane/spiropyran/zinc sulfide nano-composite microsphere prepared in example 1.

FIG. 2 is a high-temperature environment absorption spectrum diagram of the polyurethane/spiropyran/zinc sulfide nanocomposite microsphere prepared in example 1.

FIG. 3 shows normal environmental absorption spectrum of the spiropyran-based photochromic compound (III).

FIG. 4 is a high-temperature environment absorption spectrum diagram of the spiropyran photochromic compound (III).

FIG. 5 is a normal environmental absorption spectrum of the polyurethane/spiropyran nanocomposite microsphere prepared in comparative example 2.

FIG. 6 is a high-temperature environment absorption spectrum of the polyurethane/spiropyran nanocomposite microsphere prepared in comparative example 2.

Fig. 7 is a transmission electron microscope photograph of the photochromic nanocomposite microsphere prepared in example 1.

FIG. 8 is an infrared spectrum of the photochromic nanocomposite microsphere prepared in example 1 with pure zinc sulfide, spiropyran compound III, and polyurethane.

Detailed Description

The invention is further illustrated by the following specific examples, which are not intended to limit the scope of the invention.

The spiropyran-based photochromic compounds in the following examples and comparative examples were prepared by the following methods:

(1) preparation of spiropyran photochromic Compound (I):

A. adding 29g of 2, 3, 3-trimethylindole and 95g of iodohexadecane into 400g of trichloromethane solvent, heating and refluxing for 20 hours under normal pressure, evaporating to remove the solvent, adding 70g of anhydrous ether, layering, performing suction filtration, fully washing with ether, and performing vacuum drying to obtain hexadecane-2, 3, 3-trimethylindole (PS 01); dispersing PS01 in 170g of water, stirring and dropwise adding 26% NaOH solution, stopping dropwise adding after the solid completely disappears, extracting with diethyl ether after layering, washing with water, filtering, and removing diethyl ether by rotary evaporation to obtain 3, 3-dimethyl-1' -hexadecyl-2-methylindole (PS 02);

B. heating 575g of ethanol solution of 4-hydroxy-1, 3-benzene dicarbaldehyde (25 g of ethanol in the solution) in an oil bath under the protection of nitrogen till refluxing, heating to 65 ℃, dropwise adding 63g of ethanol solution containing PS02 (18 g of ethanol in the solution), continuously heating and refluxing for 6 hours after the color changes to purple, cooling to room temperature, pouring the reaction solution into ice, stirring, obtaining light purple emulsion after the ice is completely melted, fully standing, evaporating to remove water and ethanol, recrystallizing the sticky substance with methanol, filtering and drying to obtain light purple solid powder, namely the alkyl spiropyran photochromic compound (I).

(2) Preparation of spiropyran photochromic compound (II):

heating 230g of ethanol solution (containing 10g of ethanol) containing 2-hydroxy-1-naphthaldehyde to 60 ℃ in an oil bath under the protection of nitrogen until reflux, dropwise adding 24g of ethanol solution (containing 5g of ethanol) of PS02, continuously refluxing for 9 hours, cooling to room temperature, evaporating to remove the solvent, concentrating to 40%, hermetically placing in an ice bath at the temperature of minus 2 ℃ for 15 hours, carrying out suction filtration, eluting a crude product by petroleum ether and ethyl acetate in a ratio of 1: 1, and carrying out vacuum drying to obtain the alkyl-naphthospiropyran photochromic compound (II)

(3) Preparation of spiropyran photochromic compound (III):

the first step is as follows: uniformly stirring and mixing 90g of 4-hydroxy-6, 7-dimethoxy-1-phenyl-2-naphthoic acid, 170g of o-xylene and 85g of polyphosphoric acid, heating to 145 ℃, reacting for 90 minutes, pouring the reaction liquid into water, filtering, and drying in vacuum to obtain 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ] fluorene-7-ketone;

the second step is that: taking 75g of tetrahydrofuran and 95g of 5-hydroxy-2, 3-dimethoxy-7H-benzo [ c ]]Mixing fluoren-7-one, cooling to-12 deg.C, adding dropwise methyl magnesium chloride (80 g) with concentration of 3.0M, reacting at-10 deg.C for 100 min, adding saturated ammonium chloride (150 g)The solution, aqueous layer was extracted with ethyl acetate (170mL × 3), and the organic layers were combined, anhydrous Na₂SO₄Drying, vacuum evaporating solvent, and performing column chromatography to obtain 2, 3-dimethoxy-7-methyl-7H-benzo [ c ]]Fluorene-5, 7-diol;

the third step: 40g of 2, 3-dimethoxy-7-methyl-7H-benzo [ c ]]Fluorene-5, 7-diol, 250g toluene, 42g1, 1-bis (4-methoxyphenyl) -2-propyn-1-ol, 9g p-toluenesulfonic acid, stirring and mixing homogeneously, heating to 75 deg.C for reaction for 15 hours, vacuum evaporating toluene, adding 110g saturated sodium bicarbonate solution to quench the reaction, extracting the aqueous layer with ethyl acetate (90mL × 3), combining the organic layers, anhydrous Na₂SO₄Drying, decompressing and distilling out the solvent, and carrying out column chromatography on the crude product to obtain the spiropyran photochromic compound (III).

Example 1: preparation of photochromic nano composite microspheres, photochromic coating liquid and photochromic lens

Preparing photochromic nano composite microspheres:

(1) adding 9.7g of zinc nitrate hexahydrate into 1600g of ethylene glycol, stirring uniformly, adding 1.6g of sublimed sulfur powder, heating to 150 ℃, keeping the temperature, reacting for 24 hours, cooling to 55 ℃, dropwise adding 85g of mercaptoethanol, and stirring; then adding 6.7g of spiropyran photochromic compound shown in the formula III, stirring vigorously for 30 minutes, continuously cooling to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 65 ℃ for 8 hours to obtain spiropyran-coated zinc sulfide nanospheres;

(2) adding 8g of spiropyran-coated zinc sulfide nanosphere, 8.2g of diphenylmethane-4, 4' -diisocyanate (MDI) into 1000g of butyl acetate solvent, stirring uniformly, then respectively adding 7g of mixed reactants (1.2g of n-butyl alcohol, 5.8g of polytetrahydrofuran ether glycol) and 18g of Tween80, keeping the temperature at 20 ℃, carrying out prepolymerization reaction at the rotating speed of 500r/min for 60min, adding 9.2g of chain extender (6 g of ethylene glycol and 3.2g of ethylenediamine) and 0.1g of catalyst dibutyltin Dilaurate (DBTL), heating to 60 ℃, carrying out polymerization chain extension reaction for 15min, stirring at the speed of 1200r/min, filtering, washing and drying solid substances to obtain the polyurethane/spiropyran/zinc sulfide nano composite microsphere. The yield was 75%.

(3) Observing the product prepared in the step (2) by using a JEM-2100 type transmission electron microscope, as shown in figure 7, showing that the appearance is spherical, wherein the inner core with darker color is composed of a plurality of zinc sulfide nanospheres with uniform size and monodispersity, the outer layer with light color is a shell formed by the spiropyran discoloring compound and polyurethane, which can be attributed to the core-shell structure composite microsphere formed by adsorbing the spiropyran discoloring compound material by the zinc sulfide nanospheres with larger specific surface area and pore volume and coating the spiropyran discoloring compound material by the polyurethane, and the outer shell of the polyurethane is a colorless transparent material, so that the product cannot be displayed and distinguished in a transmission electron microscope photo. It is worth noting that some nanospheres have a plurality of white dots with nanometer size in the middle, which shows that the nanospheres are composed of a plurality of small particle aggregates, the white dots are pore volumes formed by gaps between particles, and the average crystal particle size of zinc sulfide and the diameter of the nanocomposite microsphere are obtained by calculation through scherrer's formula (D ═ K/β cos θ) and Zeta potential analysis, wherein the zinc sulfide nanocrystal particle size is about 4nm, the thickness of the spiropyran allochroic material and the polyurethane coating shell is about 15nm, the inner core of the zinc sulfide nanosphere is about 65nm, and the diameter of the whole composite microsphere is about 95 nm.

(4) The product prepared in the step (2) is tested by Fourier transform infrared spectroscopy (FT-IR), and the spectrogram is compared with the infrared spectrogram of pure zinc sulfide, spiropyran discolor compound III and polyurethane. The results are detailed in FIG. 8, in which curve a is an infrared spectrum of zinc sulfide; b, the curve is a spiropyran compound III infrared spectrogram; the curve c is an infrared spectrogram of the polyurethane material; the d curve is the infrared spectrum of the photochromic nanocomposite microsphere prepared in example 1.

3421cm from curve a analysis^-1The wider absorption peak is O-H stretching vibration peak, 1620cm^-1The absorption peak is the bending vibration peak of H-O-H, which is the characteristic absorption peak of water and can be attributed to the water adsorption on the surface of ZnS powder at 900-4000cm^-1There was substantially no absorption peak in the range, indicating that the ZnS powder has a good infrared transmittance.

From the analysis of the b curve in the figure, 3430cm^-12960cm, which is a stretching vibration absorption peak of-OH^-1Is represented by-CH₃Absorption peak of stretching vibration, 1640-1477cm^-1Vibration absorption peak ascribed to benzene ring, 1366cm^-1is-CH₃Flexural vibration absorption Peak, 960cm^-1Is represented by-CH₃Absorption peak of stretching vibration, 820cm^-1Is the vibration absorption peak of ortho-disubstituted benzene ring.

From the curve analysis of c in the figure, the absorption peak at 3251-3480 is the expansion vibration peak of polyurethane hydroxyl-OH; 2270cm^-1The strong absorption peak is generated by the stretching vibration of the-NCO group, other groups do not generate absorption at the peak, and the peak is the characteristic absorption peak of the isocyanate.

From the d curve analysis in the figure, 3430cm^-1Stretching vibration absorption peak at-OH, 2270cm^-1The disappearance of the vibration absorption peak indicates the absence of-NCO groups because the MDI monomer is completely reacted and the isocyanate has reacted with the compound containing weak active hydrogen atoms to form carbamate, 1706cm^-1The absorption peak at (a) represents the vibration absorption peak of-C ═ O in the polyurethane; 1460cm^-1The absorption peak at is CH₂Vibration absorption peak or CH of group (methylene)₃Despite the wave number (1366 cm) absorbed by the spiropyran molecules^-1) The inconsistency is probably caused by that after the spiropyran molecules are adsorbed to the ZnS nano particles, the absorption spectrum is shifted due to the interaction between different molecules; 1224cm^-1The absorption peak at (A) is a vibration absorption peak of the ether bond-C-O-C-.

By comparison, the infrared spectrogram of the photochromic nanocomposite microsphere prepared in example 1 not only has the characteristic absorption peak of the spiropyran derivative, but also contains the characteristic absorption peak of polyurethane, which indicates that the photochromic nanocomposite microsphere prepared in example 1 is not a single zinc sulfide substance, and also contains the spiropyran derivative and the polyurethane substance.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: 675g of 2, 3-dimercaptoethyl thiopropanethiol (BES) monomer, 120g of dichloromethane, 35g of polyurethane/spiropyran/zinc sulfide nano composite microspheres, 15g F420 wetting dispersant (product of Orner Polymer Co., Ltd., Fushan City), and 5g F300 leveling agent (product of Orner Polymer Co., Ltd., Fushan City) are added into a container, and the mixture is uniformly stirred at room temperature for 25min to obtain a component A;

2. preparing a polyurethane component B: adding 145g of m-xylylene diisocyanate curing agent, 4g of XPJ01F defoamer (product of Jiangsu Sail Xinyue defoamer Co., Ltd.), and 1g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 600g and is a first photochromic coating solution; 400g of container B, and 26g of methylene chloride was added to container B to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the polyurethane optical lens base material cleaned by NaOH into the first photochromic coating liquid for 3 minutes at room temperature, then slowly pulling the lens at the speed of 1.0mm/s, raising the speed to 1.3mm/s after 85 seconds, moving the lens into an oven, setting the temperature at 45 ℃, and baking for 80 minutes; and spraying the lens by using second photochromic liquid, and curing to obtain the spiropyran photochromic lens. Wherein the thickness of the coating was 45 μm.

Example 2:

preparing photochromic nano composite microspheres:

(1) adding 6.5g of zinc nitrate into 1600g of ethylene glycol, stirring uniformly, adding 1.7g of sublimed sulfur powder, heating to 150 ℃, reacting for 24 hours while keeping the temperature, cooling to 55 ℃, dropwise adding 70g of mercaptoethanol, and stirring; then adding 3.5g of spiropyran photochromic compound (I), stirring vigorously for 30 minutes, cooling to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 65 ℃ for 8 hours to obtain spiropyran coated zinc sulfide nanospheres;

(2) taking 5.5g of spiropyran-coated zinc sulfide nanospheres, adding 5g of MDI into 1000g of butyl acetate solvent, stirring uniformly, sequentially adding 5.5g of mixed reactants (1.0g of n-butyl alcohol, 4.5g of polytetrahydrofuran ether glycol) and 20g of Tween80, keeping the temperature at 25 ℃, carrying out prepolymerization reaction at the rotating speed of 500r/min for 50min, adding 6g of chain extenders (4.5 g of ethylene glycol, 1.5g of ethylenediamine) and 0.1g of DBTL, heating to 65 ℃ to carry out polymerization chain extension reaction for 15min, stirring at the speed of 1000r/min, filtering, washing and drying solid substances, thus obtaining the polyurethane/spiropyran/zinc sulfide nanocomposite microspheres. The yield was 74%.

The JEM-2100 type TEM photograph of the product is similar to that of FIG. 7.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: adding 610g of 1, 2, 3-trithioethyl Thiopropane (TES) monomer, 100g of dichloromethane, 40g of polyurethane/spiropyran/zinc sulfide nano composite microspheres, 10g F420 wetting dispersant and 5g F320 flatting agent (product of Olympic polymer Co., Ltd., Fushan City) into a container, and uniformly stirring at room temperature for 20min to obtain a component A;

2. preparing a polyurethane component B: adding 150g of m-xylylene diisocyanate curing agent, 6g of XPJ01F defoaming agent and 3g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 600g and is a first photochromic coating solution; 324g of container B, and 20g of methylene chloride were added to the container B to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the hardened polyurethane optical lens base material into the first photochromic coating liquid for 3 minutes at room temperature, then slowly lifting the lens, wherein the lifting speed is 1.0mm/s, the speed is increased to 1.3mm/s after 85 seconds, moving the lens into an oven, setting the temperature at 45 ℃, and baking for 70 minutes; and spraying the lens by using second photochromic liquid, and curing to obtain the spiropyran photochromic lens. Wherein the coating thickness was 43 μm.

Example 3:

preparing photochromic nano composite microspheres:

(1) adding 11g of zinc nitrate hexahydrate into 1600g of ethylene glycol, uniformly stirring, adding 3g of sulfur powder, heating to 145 ℃, reacting for 24 hours while keeping the temperature, cooling to 50 ℃, dropwise adding 92g of mercaptoethanol, and stirring; adding 8g of spiropyran photochromic compound (I), stirring vigorously for 35 minutes, continuously cooling to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 60 ℃ for 9 hours to obtain spiropyran coated zinc sulfide nanospheres;

(2) adding 10g of spiropyran-coated zinc sulfide nanospheres, 10.8g of m-Xylylene Diisocyanate (XDI) into 1000g of butyl acetate solvent, stirring uniformly, sequentially adding 7.4g of mixed reactants (1.0g of n-butanol, 6.4g of polytetrahydrofuran ether glycol) and 16g of Tween80, keeping the temperature at 25 ℃, carrying out prepolymerization reaction at the rotating speed of 600r/min for 60min, adding 8g of chain extenders (5.5 g of ethylene glycol, 2.5g of ethylenediamine) and 0.2g of DBTL, heating to 60 ℃, carrying out polymerization chain extension reaction for 15min, stirring at the speed of 1300r/min, filtering, washing and drying solid substances to obtain the polyurethane/spiropyran/zinc sulfide nano composite microspheres. The yield was 73%.

The JEM-2100 type TEM photograph of the product is similar to that of FIG. 7.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: adding 710g TES monomer, 130g dichloromethane, 50g polyurethane/spiropyran/zinc sulfide nano composite microspheres, 18g F420 wetting dispersant and 10g F320 flatting agent into a container, and uniformly stirring at room temperature for 25min to obtain a component A;

2. preparing a polyurethane component B: adding 140g of m-toluene diisocyanate curing agent, 6g of XPJ01F defoaming agent and 5g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 600g and is a first photochromic coating solution; 469g of B vessel, 30g of methylene chloride was added to the B vessel to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the acid-washed polyurethane optical lens base material into the first photochromic coating liquid for 3 minutes at room temperature, then slowly lifting the lens, wherein the lifting speed is 1.0mm/s, the speed is increased to 1.3mm/s after 90 seconds, moving the lens into a drying oven, setting the temperature at 45 ℃, and baking for 70 minutes; and immersing the lens into second photochromic coating liquid again, wherein the method is the same as that of the first immersion coating, and curing to obtain the spiropyran photochromic lens. Wherein the thickness of the coating was 45 μm.

Example 4:

preparing photochromic nano composite microspheres:

(1) adding 14g of zinc nitrate hexahydrate into 1600g of ethylene glycol, uniformly stirring, adding 2g of sublimed sulfur powder, heating to 150 ℃, reacting for 23 hours while keeping the temperature, cooling to 50 ℃, dropwise adding 100g of mercaptoethanol, and stirring; adding 12g of spiropyran photochromic compound (II), stirring vigorously for 35 minutes, continuing cooling to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 60 ℃ for 9 hours to obtain spiropyran coated zinc sulfide nanospheres;

(2) adding 12g of spiropyran-coated zinc sulfide nanosphere and 11.5g of XDI into 1000g of butyl acetate solvent, stirring uniformly, sequentially adding 8.5g of mixed reactants (1g of n-butyl alcohol, 7.5g of polytetrahydrofuran ether glycol), 20g of Tween80, keeping the temperature at 20 ℃, carrying out prepolymerization reaction at the rotation speed of 650r/min for 60min, adding 8g of chain extender (5.5 g of ethylene glycol, 2.5g of ethylenediamine) and 0.2g of DBTL, heating to 60 ℃ to carry out polymerization chain extension reaction for 15min, stirring at the speed of 1200r/min, filtering, washing and drying solid substances to obtain the polyurethane/spiropyran/zinc sulfide nano composite microsphere. The yield was 72%.

The JEM-2100 type TEM photograph of the product is similar to that of FIG. 7.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: adding 750g of 2, 2' -dimercaptoethylsulfide (MES) monomer, 150g of dichloromethane, 50g of polyurethane/spiropyran/zinc sulfide nano composite microspheres, 20g F420 wetting dispersant and 10g F300 leveling agent into a container, and uniformly stirring at room temperature for 25min to obtain a component A;

2. preparing a polyurethane component B: adding 120g of methyl cyclohexyl diisocyanate curing agent, 7g of XPJ01F defoaming agent and 6g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 600g and is a first photochromic coating solution; in vessel B513 g, 30g of methylene chloride was added to vessel B to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the hardened polyurethane optical lens base material into the first photochromic coating liquid for 3 minutes at room temperature, then slowly lifting the lens, wherein the lifting speed is 0.9mm/s, the speed is increased to 1.4mm/s after 95 seconds, moving the lens into an oven, setting the temperature at 50 ℃, and baking for 75 minutes; and then immersing the lens into second photochromic coating liquid, wherein the method is the same as the first immersion coating, and curing to obtain the spiropyran photochromic lens. Wherein the coating thickness was 44 μm.

Example 5:

preparing photochromic nano composite microspheres:

(1) adding 8g of zinc nitrate hexahydrate into 1600g of ethylene glycol, uniformly stirring, adding 2.5g of sublimed sulfur powder, heating to 150 ℃, reacting for 23 hours while keeping the temperature, cooling to 50 ℃, dropwise adding 82g of mercaptoethanol, and stirring; then adding 5.2g of spiropyran photochromic compound (III), stirring vigorously for 35 minutes, cooling to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 60 ℃ for 9 hours to obtain spiropyran coated zinc sulfide nanospheres;

(2) adding 6.6g of spiropyran-coated zinc sulfide nanosphere, 5.6g of Toluene Diisocyanate (TDI) into 1000g of butyl acetate solvent, stirring uniformly, sequentially adding 6.3g of mixed reactants (0.9g of n-butyl alcohol, 5.4g of polytetrahydrofuran ether glycol) and 14g of Tween80, keeping the temperature at 25 ℃, carrying out prepolymerization reaction at the rotating speed of 700r/min for 60min, adding 5.5g of chain extender (4.5 g of ethylene glycol and 1g of ethylenediamine) and 0.1g of DBTL, heating to 60 ℃ for carrying out polymerization chain extension reaction for 15min, stirring at the speed of 1500r/min, filtering, washing and drying solid substances to obtain the polyurethane/spiropyran/zinc sulfide nano composite microsphere. The yield was 74%.

The JEM-2100 type TEM photograph of the product is similar to that of FIG. 7.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: adding 640g of BES monomer, 110g of dichloromethane, 25g of polyurethane/spiropyran/zinc sulfide nano composite microspheres, 17g F420 wetting dispersant and 5g F309 flatting agent into a container, and uniformly stirring at room temperature for 25min to obtain a component A;

2. preparing a polyurethane component B: adding 110g of m-xylylene diisocyanate curing agent, 9g of XPJ01F defoaming agent and 7g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 700g and is a first photochromic coating solution; in the B vessel 223g, 15g of methylene chloride was added to the B vessel to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the hardened polyurethane optical lens base material into the first photochromic coating liquid for 3 minutes at room temperature, then slowly lifting the lens, wherein the lifting speed is 1.1mm/s, the speed is increased to 1.34mm/s after 85 seconds, moving the lens into an oven, setting the temperature at 45 ℃, and baking for 70 minutes; and spraying the lens by using second photochromic liquid, and curing to obtain the spiropyran photochromic lens. Wherein the coating thickness was 43 μm.

Example 6:

preparing photochromic nano composite microspheres:

(1) adding 8g of zinc nitrate hexahydrate into 1600g of ethylene glycol, uniformly stirring, adding 2.7g of sublimed sulfur powder, heating to 150 ℃, reacting for 23 hours while keeping the temperature, cooling to 45 ℃, dropwise adding 80g of mercaptoethanol, and stirring; then adding 5.9g of spiropyran photochromic compound (II), stirring vigorously for 35 minutes, continuing to cool to room temperature, filtering and washing the precipitate, and drying in a vacuum drying oven at 60 ℃ for 9 hours to obtain spiropyran-coated zinc sulfide nanospheres;

(2) adding 7.2g of spiropyran-coated zinc sulfide nanosphere and 6.9g of TDI into 1000g of butyl acetate solvent, stirring uniformly, sequentially adding 6.5g of mixed reactants (1.5g of n-butyl alcohol, 5.0g of polytetrahydrofuran ether glycol) and 12g of Tween80, keeping the temperature at 25 ℃, carrying out prepolymerization reaction at the rotating speed of 500r/min for 60min, adding 7g of chain extender (5.5 g of ethylene glycol, 1.5g of ethylenediamine) and 0.1g of DBTL, heating to 70 ℃ to carry out polymerization chain extension reaction for 15min, stirring at the speed of 1500r/min, filtering solid substances, washing and drying to obtain the polyurethane/spiropyran/zinc sulfide nano composite microsphere. The yield was 73%.

The JEM-2100 type TEM photograph of the product is similar to that of FIG. 7.

(II) preparing a photochromic coating liquid:

1. preparing a polyurethane component A: adding 660g of MES monomer, 140g of dichloromethane, 30g of polyurethane/spiropyran/zinc sulfide nano composite microspheres, 16g F420 wetting dispersant and 5g F320 flatting agent into a container, and uniformly stirring at room temperature for 25min to obtain a component A;

2. preparing a polyurethane component B: adding 100g of diphenylmethane-4, 4' -diisocyanate curing agent, 8g of XPJ01F defoaming agent and 8g of DBTL catalyst into a container, and uniformly stirring for 5 minutes at room temperature to obtain a component B;

3. preparing a photochromic coating liquid: uniformly mixing the component A and the component B, and subpackaging in A, B containers, wherein the container A is 600g and is a first photochromic coating solution; 367g of container B, 17g of methylene chloride was added to container B to obtain a second photochromic coating solution.

(III) preparing a photochromic lens:

soaking the hardened polyurethane optical lens base material into the first photochromic coating liquid for 4 minutes at room temperature, then slowly pulling the lens at the speed of 0.9mm/s, raising the speed to 1.4mm/s after 80 seconds, moving the lens into a drying oven, setting the temperature at 60 ℃, and baking for 60 minutes; and then immersing the lens into second photochromic coating liquid, wherein the method is the same as the first immersion coating, and curing to obtain the spiropyran photochromic lens. Wherein the thickness of the coating was 45 μm.

Comparative example 1:

photochromic coating liquids and photochromic lenses were prepared using the same operating conditions as in the steps (two) and (three) of example 1, except that the polyurethane/spiropyran/zinc sulfide nanocomposite microspheres were replaced with the spiropyran photochromic compound (III) in the preparation of the photochromic coating liquids.

Comparative example 2:

(1) the same operation conditions as those of the steps (one) - (2) of the example 1 are adopted, except that the spiropyran photochromic compound (III) is used for replacing the spiropyran to coat the zinc sulfide nanospheres, and the polyurethane/spiropyran nano composite microspheres are obtained.

(2) And (2) preparing photochromic coating liquid and photochromic lenses by adopting the same operation conditions as the steps (II) and (III) of the example 1, wherein the polyurethane/spiropyran/zinc sulfide nano composite microspheres obtained in the step (1) are used for replacing the polyurethane/spiropyran/zinc sulfide nano composite microspheres in the process of preparing the photochromic coating liquid.

Example 7: the photochromic materials prepared in example 1 and comparative examples 1 to 2 were respectively subjected to oxidation resistance tests

Respectively carrying out absorption spectrum detection on the polyurethane/spiropyran/zinc sulfide nano composite microspheres prepared in the embodiment 1, the spiropyran photochromic compound (III) and the polyurethane/spiropyran nano composite microspheres prepared in the comparative example 2;

(1) a detection step: taking 5g of the materials, dissolving the materials in 9mL of tetrahydrofuran, subpackaging and pouring the materials into a plurality of glass beakers, respectively placing one marked part into a sunlight simulation box for irradiation detection, irradiating for 15min at normal temperature, wherein the distance between the solution and a light source is 16CM, the radiation quantity hv is 2Eg, recording the difference between the absorption spectra of the solution before irradiation and after irradiation, and the detection result is shown in figure 1, figure 3, figure 5 and a table I.

TABLE-absorption Spectrum Difference (Δ OD) of solution under Normal Environment

(2) A detection step: respectively putting 5g of the polyurethane/spiropyran/zinc sulfide nano composite microspheres prepared in the example 1, 5g of the spiropyran photochromic compound (III) and 5g of the polyurethane/spiropyran nano composite microspheres prepared in the comparative example 2 into three crucibles, transferring the crucibles into a muffle furnace, uniformly heating to 200 ℃, and standing at the temperature for 28 hours; and taking out the photochromic compounds, respectively dissolving the photochromic compounds in 9mL of tetrahydrofuran, subpackaging and pouring the mixture into a plurality of glass beakers, respectively placing one marked part into a sunlight simulation box for irradiation detection, irradiating for 15min at normal temperature, wherein the distance between the solution and a light source is 16CM, the radiation quantity hv is 2Eg, and recording the difference between the absorption spectra of the solution before and after irradiation, wherein the detection results are shown in figure 2, figure 4, figure 6 and table two.

TABLE II absorption Spectrum Difference (Δ OD) of solution at high temperature

(II) anti-aging tests were performed on the photochromic lenses prepared in examples 1 to 6 and comparative examples 1 to 2, respectively

The detection steps and the method are as follows: the photochromic lenses prepared in the examples 1-6 and the comparative examples 1-2 are respectively subjected to irradiation ageing resistance experiments, the experimental equipment adopts a ZN-P type ultraviolet light ageing test box of the tin-free aerospace engineering technology Limited company, the temperature is set to be 60 ℃, the irradiation intensity selects the extreme irradiation condition, after identification, the irradiation is respectively carried out for 15 minutes and 48 hours, the transmittance data before and after irradiation are recorded, and the detection results are shown in the third table.

Table three photochromic lens transmittance (%)

And (4) test conclusion: the absorption spectrum of a solution containing polyurethane/spiropyran/zinc sulfide nano composite microspheres is unchanged (no difference) in normal environment and high-temperature environment; the absorption spectrum of the photochromic solution prepared in the comparative example 1-2 is changed under normal environment and high temperature environment, the change value at 550nm reaches 0.9, and the change value at 750nm reaches 1; and (II) the transmittance data of the photochromic lens containing the polyurethane/spiropyran/zinc sulfide nano composite microsphere coating before and after irradiation has no difference, while the transmittance data of the photochromic lens prepared in the comparative example 1-2 before and after irradiation has a larger difference, and the change values respectively reach 15 and 16.

The fatigue resistance of the photochromic material is mostly reflected by the change of absorbance or transmittance after discoloration, so the fatigue resistance is measured by the change of the absorbance before and after irradiation and the change of the transmittance, and the following conclusion is obtained by comparing test data: the optical material containing the polyurethane/spiropyran/zinc sulfide nano composite microspheres has stronger fatigue resistance.

Example 8: photochromic response test was performed on the resin lenses prepared in examples 1 to 6 and comparative examples 1 to 2, respectively

Photochromic response value test

The detection steps and the method are as follows: the ratio between the light transmittance tV (0) of the tested sample in the faded state and the light transmittance tV (1) of the discolored state after different illumination times (1-15min), namely: the spectral response value is tV (0) ÷ tV (1) to determine the photochromic response value of the tested sample at different temperatures. After the radiation intensity of the solar simulator is attenuated by 25%, the sample is irradiated with medium illumination intensity, the temperature is set to be 23 ℃, and the detection result is shown in the fourth table.

TABLE IV conditions of photochromic response values of test samples

(II) photochromic spectral response time detection

The detection steps and the method are as follows: placing the photochromic lenses prepared in examples 1-6 and comparative examples 1-2 into a test box respectively, turning on a solar simulator light source, and recording the time required for the lenses to change from colorless to colored; after 10 minutes of irradiation, the simulated light source is turned off, the time required for the lens to return to the colorless state from the colored state is recorded, and the detection result is shown in table five.

TABLE V detection of spectral response time of samples

In summary, the following steps: the optical material and the lens containing the polyurethane/spiropyran/zinc sulfide nano composite microspheres manufactured by the invention have the advantages of short photochromic response time, high spectral response sensitivity and the like.

Claims

1. The photochromic coating liquid is characterized by comprising polyurethane/spiropyran/zinc sulfide photochromic composite microspheres, wherein the photochromic composite microspheres are of a three-layer composite core-shell structure, the inner core of the photochromic composite microspheres is zinc sulfide mesoporous nano microspheres, the middle layer of the photochromic composite microspheres is a photochromic layer formed by spiropyran compounds, and the outer shell of the photochromic composite microspheres is polyurethane; the composite microsphere has the outer diameter of 50-350nm, wherein the diameter of the zinc sulfide mesoporous nano microsphere is 30-250 nm, the thickness of the middle layer is 5-25 nm, and the thickness of the shell is 5-25 nm.

2. The photochromic coating solution of claim 1, wherein the zinc sulfide mesoporous nanospheres are monodisperse zinc sulfide mesoporous nanospheres composed of zinc sulfide nanocrystals, and the intermediate layer is a nano composite mesoporous structure formed by uniformly dispersing spiropyran compound nanoparticles on the surface or in the gaps of the zinc sulfide mesoporous nanospheres.

3. The photochromic coating fluid of claim 1 or 2, wherein the spiropyran-based compound is selected from the group consisting of compounds of formula (I) or formula (II):

wherein R ═ C₁₆H₃₃

Wherein R ═ C₁₆H₃₃。

4. The photochromic coating solution of claim 1, wherein the polyurethane is prepared by polymerizing an isocyanate monomer compound containing two or more isocyanate groups with an alcohol compound.

5. The photochromic coating fluid of claim 4 wherein the isocyanate monomer compound is selected from the group consisting of: at least one of toluene diisocyanate, diphenylmethane-4, 4' -diisocyanate, 1, 6-hexamethylene diisocyanate, m-xylylene diisocyanate, naphthalene-1, 5-diisocyanate, methylcyclohexyl diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, and isophorone diisocyanate;

the alcohol compound is at least one of n-butyl alcohol, polytetrahydrofuran ether glycol, pentaerythritol, ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol and trimethylolpropane.

6. The photochromic coating solution of any one of claims 1 to 5, wherein the coating solution consists of the following components in parts by weight:

(1) a component A:

(2) b, component B:

isocyanate type curing agent 12-17

Catalyst 0-1

0-1 part of defoaming agent.

7. The photochromic coating solution of claim 6, wherein the polythiourethane monomer is at least one of 2, 2 '-dimercaptoethylsulfide, 2' -dimercaptoethylthioethane, 2, 3-dimercaptoethylthiopropanethiol, or 1, 2, 3-trimercaptoethylthiopropane;

the isocyanate type curing agent is at least one of a toluene diisocyanate curing agent, a diphenylmethane-4, 4' -diisocyanate curing agent, a 1, 6-hexamethylene diisocyanate curing agent, an m-xylylene diisocyanate curing agent, a methylcyclohexyl diisocyanate curing agent and an isophorone diisocyanate curing agent;

the catalyst is dibutyltin dilaurate.

8. The photochromic coating solution of claim 6, wherein the diluent is at least one of dichloromethane, butyl acetate, methyl acetate, ethanol, butanol, acetone, toluene, xylene, diethyl ether and polytetrahydrofuran ether glycol;

the wetting dispersant is a BYK polyurethane type special wetting dispersant or an F420 type wetting dispersant;

the leveling agent is an oily F300 type leveling agent, an F309 type leveling agent or an F320 type leveling agent;

the defoaming agent is XPJ01F type modified silicone oil defoaming agent.

9. A process for the preparation of a photochromic coating fluid according to any one of claims 6 to 8, comprising the following operative steps:

10. The photochromic coating solution of any one of claims 1 to 8 for preparing a photochromic coating layer of an optical substrate, wherein the component A and the component B are mixed and coated on the surface of the optical substrate to form a coating layer, and then cured by light irradiation or heating to prepare the photochromic coating layer.

11. The photochromic coating liquid is characterized by comprising polyurethane/a compound shown in formula III/zinc sulfide photochromic composite microspheres, wherein the photochromic composite microspheres are of a three-layer composite core-shell structure, the inner core of the photochromic composite microspheres is zinc sulfide mesoporous nano microspheres, the middle layer of the photochromic composite microspheres is a photochromic layer formed by the compound shown in formula III, and the shell of the photochromic composite microspheres is polyurethane; the outer diameter of the composite microsphere is 50-350nm, wherein the diameter of the zinc sulfide mesoporous nano microsphere is 30-250 nm, the thickness of the middle layer is 5-25 nm, and the thickness of the shell is 5-25 nm;

12. the photochromic coating solution of claim 11, wherein the zinc sulfide mesoporous nanospheres are monodisperse zinc sulfide mesoporous nanospheres composed of zinc sulfide nanocrystals, and the intermediate layer is a nano composite mesoporous structure formed by uniformly dispersing the compound nanoparticles of formula III on the surface or in the gaps of the zinc sulfide mesoporous nanospheres.

13. The photochromic coating solution of claim 11, wherein the polyurethane is formed by polymerizing an isocyanate monomer compound containing two or more isocyanate groups and an alcohol compound.

14. The photochromic coating fluid of claim 13 wherein the isocyanate monomer compound is selected from the group consisting of: at least one of toluene diisocyanate, diphenylmethane-4, 4' -diisocyanate, 1, 6-hexamethylene diisocyanate, m-xylylene diisocyanate, naphthalene-1, 5-diisocyanate, methylcyclohexyl diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, and isophorone diisocyanate;

15. The photochromic coating solution of any one of claims 11-14, wherein the coating solution comprises the following components in parts by weight:

(1) a component A:

(2) b, component B:

isocyanate type curing agent 12-17

Catalyst 0-1

0-1 part of defoaming agent.

16. The photochromic coating solution of claim 15, wherein the polythiourethane monomer is at least one of 2, 2 '-dimercaptoethylsulfide, 2' -dimercaptoethylthioethane, 2, 3-dimercaptoethylthiopropanethiol, or 1, 2, 3-trimercaptoethylthiopropane;

the catalyst is dibutyltin dilaurate.

17. The photochromic coating solution of claim 15 wherein the diluent is at least one of dichloromethane, butyl acetate, methyl acetate, ethanol, butanol, acetone, toluene, xylene, diethyl ether and polytetrahydrofuran ether glycol;

the defoaming agent is XPJ01F type modified silicone oil defoaming agent.

18. A process for the preparation of a photochromic coating fluid according to any one of claims 15 to 17, comprising the following operative steps:

(1) a component A: adding the polythiourethane monomer, the diluent, the polyurethane/compound of formula III/zinc sulfide photochromic composite microspheres, the wetting dispersant and the flatting agent into a container according to the proportion, and uniformly stirring for 15-30 minutes at room temperature to obtain a component A;

19. The photochromic coating solution of any one of claims 11 to 17 for preparing a photochromic coating layer of an optical substrate, wherein the component a and the component b are mixed and coated on the surface of the optical substrate to form a coating layer, and then cured by light irradiation or heating to prepare the photochromic coating layer.