CN116554814A - A kind of structural color binder, preparation method and application - Google Patents

Abstract

The invention relates to a structural color binder, a preparation method and application thereof, and relates to the technical field of photonic crystal composite materials and binder service failure monitoring. Dispersing magnetic colloid particles in a polymer monomer or dispersing the magnetic colloid particles and the polymer monomer in a solvent to obtain a precursor dispersion liquid, and curing by radiation under the action of an external magnetic field to obtain a structural color binder with stress color-changing capability; dispersing non-magnetic colloid particles and polymer monomers in a solvent, obtaining precursor dispersion liquid by using a solvent volatilization method, and obtaining the structural color binder with stress color-changing capability through radiation curing. The adhesive material may change color under an external force (stretching, compressing or shearing) and may recover color when the external force is removed. The structural color is introduced, so that the capability of imparting the adhesive with the capability of imparting the color change is realized, and the visual indication function of the adhesive strength in the service process of the adhesive is realized.

Description

A kind of structural color binder, preparation method and application

technical field

The invention relates to the technical field of photonic crystal composite materials and adhesive service failure monitoring, and more specifically relates to a structural color adhesive, a preparation method and an application. The invention relates to a preparation method of a structural color adhesive and a preparation method including a structural color adhesive with mechanochromic ability, the design and preparation thereof are used for the coloring of adhesive materials, and a bonding agent with mechanochromic ability Agent materials are used for stress detection and early warning of material service failure.

Background technique

In many fields such as automobiles, electronic equipment, mechanical parts, building materials, and daily offices, the use of adhesive bonding instead of mechanical bonding is increasing. Acrylic resin has good weather resistance, acid and alkali resistance and light resistance, and is mainly used in the fields of coatings, fabric treatment and adhesives. Polyacrylate binders have the characteristics of fast curing, low energy consumption, high transparency, and limited emission of volatile organic substances, and are widely used in glass, ceramics, wood, leather, printing and other fields. Structural color is a color produced by the interaction between light of a specific wavelength and the microscopic nanostructure inside the material. It is a physical color production method. Different from the colors produced by traditional dyes and pigments, structural colors have the advantages of high brightness, high color saturation and insensitivity to ultraviolet light. Structurally colored nanocomposites obtained by embedding photonic crystal arrays into soft and highly transparent polymers have been widely developed and have great application potential in sensing, biodetection, flexible display devices, etc. To meet the various needs of human beings for color, the application of structural color to the field of color coating has very important research value.

At present, most of the adhesives produced in the industry are colorless. With the diversification of people's needs for bonding colors and functions, some companies have produced colored adhesives, such as colored solid adhesives and discolored solid adhesives. But existing method all is to add pigment or pigment (dye) to color in production process. For example, CN1055944A is to obtain the solid adhesive of multiple colors by adding food coloring or pigment (dye) to the solid adhesive. The color-changing adhesive is mainly phenolphthalein solid adhesive in the bottle. CN101608103A discloses a highly stable discoloration solid adhesive based on phenolphthalein. After being coated on a substrate, the alkalinity of the adhesive decreases after contacting with air, and the purple color disappears when the pH is lower than 8.2. Existing color adhesives are faced with the problem of colorants (dyes, pigments) being degraded and discolored after long-term exposure in the air, and color-changing adhesives do not have the ability to indicate color changes for dislocations caused by substrate deformation or decreased adhesive force of joints.

Contents of the invention

Aiming at the shortage of existing color binders and the needs of special application scenarios, the present invention provides a rapid and large-scale method for preparing structural color binders. According to the characteristics of different colloidal particles, the preparation process, the selection of solvent, the ratio of components and the assembly parameters are optimized, so as to realize large-scale structural color adhesion. Preparation of binders and color-changing binders. This technology improves the optical stability of the color adhesive, and increases the functionality of the structural color adhesive, which can realize the visual monitoring and early warning of the bonding performance, and promotes the industrial development of the structural color adhesive.

To achieve the above objectives, the present invention provides a method for preparing an adhesive with structural color, which realizes the coloring of the adhesive. The structural color adhesive prepared by the invention has the ability to change color, and can visually indicate the adhesion performance of the adhesive according to the color change.

According to the first aspect of the present invention, a kind of preparation method of structural color adhesive is provided, comprising the following steps:

(1) dispersing the magnetic colloid particles and the photoinitiator in the polymer monomer to obtain a precursor dispersion; or dispersing the magnetic colloid particles, the polymer monomer and the photoinitiator in a solvent to obtain a precursor dispersion;

(2) Applying a magnetic field to the precursor dispersion obtained in step (1), the magnetic colloid particles are arranged in an orderly manner under the action of the magnetic field to generate structural color, and then undergo radiation curing to obtain a structural color binder.

Preferably, in the precursor dispersion, the mass fraction of the magnetic colloid particles ranges from 1% to 10%.

Preferably, the magnetic colloidal particles are ferric oxide colloidal particles or paramagnetic colloidal particles of ferric oxide coated with a shell;

Preferably, the paramagnetic colloidal particles of ferroferric oxide coated with the shell layer are colloidal particles of ferric oxide coated with a shell of silica or colloidal particles of ferric oxide coated with polyvinylpyrrolidone;

Preferably, the size distribution of the magnetic colloidal particles is 100-400 nm.

According to another aspect of the present invention, a kind of preparation method of structural color adhesive is provided, comprising the following steps:

(1) Disperse non-magnetic colloidal particles, polymer monomers and photoinitiators in a solvent to obtain a dispersion; place the dispersion in a heat field in a dark environment to volatilize and remove the solvent to obtain a precursor dispersion with structural color ;

(2) Radiation curing the precursor dispersion liquid with structural color obtained in step (1) to obtain a structural color binder.

Preferably, in the dispersion liquid, the volume fraction of the non-magnetic colloidal particles ranges from 30% to 80%.

Preferably, the nonmagnetic colloidal particles are zirconia colloidal particles, silica colloidal particles, titanium dioxide colloidal particles, cerium oxide colloidal particles, zinc sulfide colloidal particles, cellulose nanocrystals or polymeric colloidal particles;

Preferably, the polymer colloidal particles are polystyrene colloidal particles, polydopamine colloidal particles or polymethyl methacrylate colloidal particles;

Preferably, the size distribution of the non-magnetic colloidal particles is 100-400 nm.

Preferably, the polymer monomer is an acrylate monomer and/or a methacrylate monomer.

According to another aspect of the present invention, there is provided the structural color adhesive prepared by any method, the color of the structural color adhesive can change under the action of external force, and the color can be restored when the external force is removed.

Preferably, the external force is tension, compression or shear.

According to another aspect of the present invention, an application of the structural color adhesive for monitoring changes in bonding strength or detecting stress under load is provided.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

(1) Compared with traditional colorants (dyes, pigments), the coloring of the binder in the present invention has the advantages of being stable and not easy to fade; and it has the ability to indicate responsive discoloration to the deformation of the substrate or binder.

(2) The introduction of structural color in the present invention endows the adhesive with the ability of mechanochromism, and realizes the visual indication function of the adhesive strength during the service process of the adhesive. For example, during the service of the adhesive, due to the influence of ambient temperature, humidity, radiation, etc., the bonding ability of the adhesive decreases, and under the action of load force, it is prone to creep and cause the dislocation or debonding of the adhesive head. For the process of adhesive creep failure, structural color can respond and produce color changes, which can be intuitively perceived by the naked eye, and are also easily captured by optical devices such as monitors, digital cameras, and smartphones.

(3) The method of the present invention is simple, based on the improvement of the existing adhesive production process, the structural color adhesive can be prepared by adding colloidal particles that can produce structural color, the cost is low, and it is easy to scale up.

(4) The present invention can obtain structural color binders with different hydrophilicity, hydrophobicity, glass transition temperature and functionality by selecting the types of polymer monomers.

(5) The present invention provides a new solution for realizing the early warning of binder service failure, which is of great significance to the safety of production and life. For example, a blue structural color binder remains blue in a steady state. When the ambient humidity is too high, the cohesive energy of the binder will decrease, and the binder will gradually deform under the action of the load. This deformation process will cause the structural color to change from blue to green, yellow or red. The color change of the adhesive can inform the user that the adhesive performance of the adhesive has declined, and the adhesive should be replaced in time to prevent potential adhesion failure.

Description of drawings

Fig. 1 is a schematic diagram of the preparation and structure of the structural color adhesive of the present invention.

Fig. 2 is a schematic diagram of the preparation and structure of the structural color binder doped with magnetic colloid particles in Examples 1-5.

3 is a schematic diagram of the preparation and structure of the structural color binder doped with non-magnetic colloidal particles in Examples 6-8.

Fig. 4 is a scanning electron micrograph of the magnetic trioxide tetroxide colloidal particles used in the preparation of the structural color binder in Examples 1-5.

Fig. 5 is a scanning electron micrograph of the non-magnetic silica colloidal particles used in the preparation of the structural color binder in Examples 6-8.

6 is a schematic diagram of the color change response mechanism of Embodiment 1-5 under the shear force of the structural color binder doped with magnetic colloid particles.

Fig. 7 shows that the structural color adhesive prepared in Example 2 is used for bonding glass and carrying heavy objects.

Figure 8 shows the red shift of the color caused by the decrease of the bonding strength of the structural color adhesive prepared in Example 2 serving in a high-humidity environment.

Figure 9 shows the service of the structural color binder prepared in Example 3 in underwater environment.

Figure 10 shows that the structural color adhesive prepared in Example 4 fails from blue to brownish yellow when it fails at high temperature.

Fig. 11 is a schematic diagram of the color change response mechanism of the structural color binders prepared in Examples 1-8 under tension or compression.

Fig. 12 is a shear discoloration effect diagram of the structural color binder doped with non-magnetic colloidal particles prepared in Example 8.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The invention discloses a rapid and large-scale method for preparing a structural color adhesive, and relates to the technical field of photonic crystal composite materials and adhesive service failure monitoring. The preparation method is: disperse the monodisperse colloidal particles in the polymer monomer, or disperse the monodisperse colloidal particles and the polymer monomer in the solvent to obtain the precursor dispersion; the colloidal particles are arranged in the polymer by self-assembly. A photonic crystal structure is formed in the matrix, and a binding agent with structural color is obtained under radiation curing; the structural color binding agent has bright colors, and is characterized in that it has the ability to change color in response to stimuli, and it can withstand external forces (stretch, compression or The adhesive can change color under the action of shearing), which can realize the monitoring of the change of the adhesive strength during the service process of the adhesive and the warning ability of the adhesive failure. Fig. 1 is a schematic diagram of the preparation and structure of the structural color adhesive of the present invention.

Colloidal particles can be divided into magnetic colloidal particles and non-magnetic colloidal particles; the self-assembly of magnetic colloidal particles can be induced by a magnetic field, and the magnetic colloidal particles can be arranged to form a chain structure under a magnetic field to produce structural color, and the magnetic field strength ranges from 20 to 4000Gs; The self-assembly of non-magnetic colloidal particles can adopt the solvent volatilization method, which is characterized in that the temperature can be controlled at 0-100°C.

Preferably, the magnetic nanoparticles are ferric oxide; the non-magnetic nanoparticles are zirconium dioxide, silicon dioxide, titanium dioxide, cerium oxide, or zinc sulfide colloidal particles, cellulose nanocrystals, or polymer colloidal particles, such as polyphenylene Ethylene, polydopamine, polymethyl methacrylate, etc.; colloidal particles can be one or a mixture of the above.

In some embodiments, the colloidal particles used have a size distribution of 100-400 nm.

In some embodiments, the polymer monomers are acrylate monomers and/or methacrylate monomers.

In some embodiments, the difference in refractive index between the colloidal particles and the polymer formed from the monomer is ≥0.01. If the refractive index difference of the polymer formed by the colloid and the monomer is too small, the optical gap cannot be formed, that is, the structural color cannot be produced.

In some embodiments, the acrylate and/or methacrylate monomers are selected from those having C1-20 alkyl groups, C3-8 cycloalkyl groups, C6-14 aryl groups or ethylene glycol and Acrylate and/or methacrylate units whose oligomeric derivative groups act as ester groups.

In some embodiments, the type of radiation includes UV light, visible light, electron beam, and the like.

In some embodiments, the photoinitiator comprises 2-hydroxy-2-methyl-1-phenylacetone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenyl Phosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butane-1-one-1-[4-(2- hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, benzoin alkyl ethers (such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, n-butyl benzoin ether, etc.), 2-hydroxy-2-methyl-1-phenylpropan-1-one, p-tert-butyl trichloroacetophenone, p-tert-butyl dichlorotetraethyl ketone, benzoyl, Tea ethyl ketone, benzophenone, 2,4-diisopropylthioxanthone), dibenzocycloheptanone, 4,4'-dichlorobenzophenone, 4,4'-bis(dimethyl amino) benzophenone, benzylidene acetone, diacetyl, benzoyl peroxide, 3,3'-dimethyl-4-methoxybenzophenone, 2,2-diethoxy Acetophenone, chlorinated acetophenone, hydroxyacetophenone, acetophenone diethyl ketal, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, etc.

Preparation of structural color binder for doped magnetic colloidal particles:

(1) Ultrasonic dispersion of polymer monomers, magnetic colloid particles and photoinitiators to obtain a precursor dispersion, wherein the mass fraction of magnetic colloid particles is between 1% and 10%.

(2) Inject the precursor dispersion into the mold, apply a magnetic field under the mold (the mold is preferably a transparent mold), and after the magnetic colloid particles are arranged in an orderly manner under the action of the magnetic field to produce structural color, radiation curing is obtained to obtain a structural color adhesive sheet ; or inject the precursor dispersion into the junction of the joint, apply a magnetic field under the joint and wait for the magnetic colloid particles to be arranged in an orderly manner under the action of the magnetic field to produce structural color, and then radiation curing.

Preferably, the polymer monomer is liquid at room temperature; the polymer monomer is an acrylate and/or methacrylate monomer. A non-exhaustive list of specific preferred examples includes, but is not limited to, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, hexyl acrylate, methyl Hexyl acrylate, n-octyl acrylate, n-octyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isopentyl acrylate, isooctyl acrylate, isononyl acrylate Salt, Decyl acrylate, Isodecyl acrylate, Lidecyl methacrylate, Lauryl acrylate, Lauryl methacrylate, Tridecyl acrylate, Tridecyl methacrylate, Myristyl acrylate, Methyl Myristyl acrylate, cetyl acrylate, cetyl methacrylate, 2-methylbutyl acrylate, 4-methyl-2-pentyl acrylate, 4-tert-butylcyclohexyl methacrylate, methyl Cyclohexyl acrylate, isobornyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N ,N-Dimethylaminoethylacrylamide, N,N-Dimethylaminoethylmethacrylamide, N,N-Dimethylaminopropylacrylamide, 2-hydroxyethyl acrylate, 2-methacrylic acid Hydroxyethyl ester, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, N-(2-hydroxyethyl)acrylamide, 2-hydroxybutyl methacrylate and 4 -Hydroxybutyl ester. 2-Acryloyloxyethyl Isocyanate, 2-Methacryloyloxyethyl Isocyanate, 1,1-Bis(acryloyloxymethyl)ethyl Isocyanate, Polyethylene Glycol Acrylate ester, polyethylene glycol methacrylate, polyethylene glycol methyl ether methacrylate, poly(ethylene glycol) phenyl ether acrylate, 2-phenoxyethyl acrylate, benzyl methacrylate , 2,2,3,4,4,4-hexafluorobutyl acrylate, 2-(butylamino-carbonyl) oxyethyl acrylate, 2-[2-(2-methoxyethoxy Base) ethoxy] ethyl ester, 2-methyl-2-acrylic acid-2-(2-methoxyethoxy) ethyl ester, acrylate-ethoxyethoxyethyl ester, acrylate-2-methoxyethyl base esters, and their mixtures, etc.

Preparation of structural color binder for doped non-magnetic colloidal particles:

The polymer monomer, the non-magnetic colloid particle and the photoinitiator are dispersed in the solvent through ultrasonic waves, wherein the volume fraction of the polymer monomer and the non-magnetic colloid particle is between 30% and 80%.

(1) The polymer monomer, non-magnetic colloidal particles, and the dispersion of the photoinitiator are volatilized in a heat field in a dark environment to remove the solvent to obtain a colored non-magnetic colloidal particle, polymer monomer and a small amount of solvent precursor body solution.

(2) inject the obtained colored precursor solution into a splint mold (the mold is preferably a transparent mold), and radiate curing to obtain a structural color color binder material. Or inject a colored precursor dispersion into the joint of the joint, and then cure it by radiation.

Preferably, the polymer monomers are liquid at room temperature; the polymer monomers are acrylate and/or methacrylate monomers. A non-exhaustive list of specific preferred examples includes, but is not limited to, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, N-(2-hydroxyethyl)acrylamide, 2-hydroxybutyl methacrylate and 4-hydroxybutyl acrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, polyethylene glycol methyl ether Methacrylate, poly(ethylene glycol) phenyl ether acrylate, 2-phenoxyethyl acrylate, benzyl methacrylate, 2-(butylamino-carbonyl)oxyethyl 2-acrylate , 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate, 2-methyl-2-acrylate-2-(2-methoxyethoxy)ethyl, ethyl acrylate Oxyethoxyethyl ester, 2-methoxyethyl acrylate, mixtures thereof, etc.

Preferably, the solvent is water, tetrahydrofuran, 2-phenoxyethanol, N,N-dimethylformamide, ethylene glycol phenyl ether acetate, n-hexane, diethylene glycol diacetate, cyclohexane One or more of alkanes, methanol, ethanol, isopropanol, 1-phenoxy-2-propanol, dimethyl sulfoxide, N,N-dimethylacetamide.

Preferably, the volatilization temperature of the solvent in the precursor dispersion is between 30°C and 100°C.

Preferably, the mass fraction of the non-colloidal particles in the solvent is 0.1-8%; the concentration of the polymer monomer in the solvent is 0.1-10%.

The structural color adhesive prepared by the present invention is a polymer adhesive, and factors such as ambient temperature, humidity, radiation, oxygen and the like are likely to cause aging to affect the bonding strength during service. The aging of the structural color binder will cause the bond strength to decrease during the service process, and the creep behavior of the polymer matrix will cause the deformation of the structural color binder and the red shift of the structural color, such as changing from purple or blue to green or yellow or one of red, so as to realize the monitoring of bond strength and warning of service failure.

The following are specific examples

Fig. 2 shows the preparation and structure of the structural color binder doped with magnetic colloid particles in Examples 1-5.

Fig. 4 is a scanning electron micrograph of the magnetic trioxide tetroxide colloidal particles used in the preparation of the structural color binder in Examples 1-5.

Example 1

A method for fast and large-scale preparation of structural color binders, including coleochromic structural color binders, comprising the following steps:

(1) Monodisperse ferric ferric oxide colloidal particles with a diameter of 180 nm and a photoinitiator (2-hydroxy-2-methyl-1-phenylacetone) were dispersed in polyethylene glycol methyl ether methacrylate by ultrasonic The precursor dispersion was obtained in the body (Mw480). Among them, the mass ratio of polyethylene glycol methyl ether methacrylate, iron ferric oxide colloid particles and photoinitiator is 997:3:1.

(2) Inject the precursor dispersion into the mold or joint, apply a magnetic field under the mold or joint, and irradiate with 365nm wavelength UV light for 5 minutes to cure to obtain a structural color adhesive, as shown in Figure 6, the structure Under the action of shear force, the color binder will red-shift its reflection spectrum, and has the function of mechanochromism.

Example 2

(1) Monodisperse iron ferric oxide colloidal particles with a diameter of 180nm and a photoinitiator (2-hydroxy-2-methyl-1-phenylacetone) are dispersed in polyethylene glycol methyl ether methacrylate by ultrasonic (Mw480) and N-(2-hydroxyethyl) acrylamide mixed monomer to obtain the precursor dispersion. Among them, the mass ratio of polyethylene glycol methyl ether methacrylate, N-(2-hydroxyethyl) acrylamide, colloidal particles of ferric oxide and photoinitiator is 490:507:3:1.

(2) Inject the precursor dispersion into the mold or joint, apply a magnetic field under the mold or joint, and irradiate for 5 minutes under 365nm wavelength UV light to cure to obtain a hydrophilic structural color adhesive. For example, two The glass panels are firmly bonded together. The addition of N-(2-hydroxyethyl)acrylamide significantly increased the cohesive energy of the polymer and enhanced the elastic modulus of the structural color binder. As shown in Figure 7, the obtained high cohesive energy structural color adhesive can bear a weight of 12 kg without debonding.

(3) As shown in FIG. 8 , it can be seen that the connecting piece joined by the structural color adhesive is used to carry a heavy object such as a 3kg weight, and placed in an environment with a relative humidity of 70%. With the plasticizing effect of water molecules on the binder, under the action of heavy shear force, the creep behavior of the binder causes the structural color to change from blue to yellow, indicating that the bonding strength of the binder decreases and occurs. If it is deformed and cannot carry the current heavy load, it will fail to serve.

Example 3

(1) Monodisperse ferric ferric oxide colloidal particles with a diameter of 180nm and a photoinitiator (2-hydroxyl-2-methyl-1-phenylacetone) were dispersed in 2-acrylic acid-2-(butylamino-carbonyl) by ultrasonic ) Oxoethyl ester monomer to obtain a precursor dispersion. Among them, the mass ratio of 2-acrylic acid-2-(butylamino-carbonyl)oxyethyl ester, colloidal particles of ferric oxide and photoinitiator is 997:3:1.

(2) Inject the precursor dispersion into the mold or joint, apply a magnetic field under the mold or joint, and irradiate with 365nm wavelength UV light for 5 minutes to cure to obtain a hydrophobic structural color binder, which has a mechanochromic function .

(3) As shown in Figure 9, the prepared hydrophobic structural color adhesive still maintains color and bonding performance under water.

Example 4

(1) Monodisperse ferric ferric oxide colloidal particles with a diameter of 180nm and a photoinitiator (2-hydroxy-2-methyl-1-phenylacetone) were dispersed in a mixed unit of n-butyl acrylate and isobornyl acrylate by ultrasonic A precursor dispersion liquid was obtained in the body, wherein the mass ratio of n-butyl acrylate, isobornyl acrylate, colloidal particles of ferric oxide and photoinitiator was 700:297:3:1.

(2) Inject the precursor dispersion into the mold or joint, apply a magnetic field under the mold or joint, and irradiate with 365nm wavelength UV light for 5 minutes to cure to obtain a hydrophobic structural color binder, which has a mechanochromic function .

(3) As shown in Figure 10, the prepared structural color binder softens at high temperature, and changes from blue to brownish yellow under the shear force brought by the load.

Example 5

(1) Disperse monodisperse iron ferric oxide colloidal particles with a diameter of 180nm and photoinitiator (2-hydroxy-2-methyl-1-phenylacetone) in n-butyl acrylate and 2-propylene isocyanate by ultrasonic Precursor dispersion liquid was obtained from acyloxy ethyl ester mixed monomer. The mass ratio of n-butyl acrylate, 2-acryloyloxyethyl isocyanate, colloidal particles of ferric oxide and photoinitiator is 800:197:3:1.

(2) Inject the precursor dispersion into the mold or joint, apply a magnetic field under the mold or joint, and irradiate for 5 minutes under 365nm wavelength UV light to cure to obtain a structural color adhesive with mechanochromic function.

Fig. 3 shows the preparation and structure of the structural color binder doped with non-magnetic colloidal particles in Examples 6-8.

Fig. 5 is a scanning electron micrograph of the non-magnetic silica colloidal particles used in the preparation of the structural color binder in Examples 6-8.

Example 6

(1) Monodisperse colloidal silica particles with a diameter of 180nm, photoinitiator (2-hydroxy-2-methyl-1-phenylacetone), polyethylene glycol methyl ether methacrylate monomer (Mw 480 ) was ultrasonically dispersed in an ethanol solution, and the ethanol solvent was evaporated to remove the ethanol solvent in a dark environment at 80°C to obtain a colored precursor solution. The volume ratio of polyethylene glycol methyl ether methacrylate, silica colloid particles and photoinitiator is 500:500:1.

(2) Inject the obtained colored precursor solution into the transparent splint mold or the joint, and irradiate it under 365nm wavelength UV light for 5 minutes to cure to obtain a structural color adhesive with mechanochromic function. As shown in the reflectance spectrum in Figure 11, the color of the structural color binder shifts blue when it is stretched or compressed.

Example 7

(1) Monodisperse colloidal silica particles with a diameter of 180nm, a photoinitiator (2-hydroxy-2-methyl-1-phenylacetone) and 2-methyl-2-acrylic acid-2-(2-methyl The oxyethoxy) ethyl ester is ultrasonically dispersed in the ethanol solution, and the ethanol solvent is volatilized to remove the ethanol solvent in a dark environment at 80°C to obtain a colored precursor solution. Wherein the volume ratio of 2-methyl-2-acrylic acid-2-(2-methoxyethoxy) ethyl ester, silica colloid particles and photoinitiator is 500:500:1.

(2) Inject the obtained colored precursor solution into a transparent splint mold or joint, and irradiate it with 365nm wavelength UV light for 5 minutes to cure to obtain a structural color adhesive with mechanochromic function.

Example 8

(1) Monodisperse colloidal silica particles with a diameter of 180nm, photoinitiator (2-hydroxyl-2-methyl-1-phenylacetone), 2-acrylic acid-2-(butylamino-carbonyl)oxoethyl The ester was ultrasonically dispersed in the ethanol solution, and the ethanol solvent was evaporated to remove the ethanol solvent in a dark environment at 80°C to obtain a colored precursor solution. Wherein the volume ratio of 2-acrylic acid-2-(butylamino-carbonyl)oxyethyl ester, silica colloid particles and photoinitiator is 500:500:1.

(2) Inject the obtained colored precursor solution into a transparent splint mold or joint, and irradiate it with 365nm wavelength UV light for 5 minutes to cure to obtain a structural color adhesive with mechanochromic function. As shown in Figure 12, the structural color adhesive changes from blue to orange under the action of shear force.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (10)

1. The preparation method of the structural color binder is characterized by comprising the following steps of:

(1) Dispersing magnetic colloid particles and a photoinitiator in a polymer monomer to obtain precursor dispersion liquid; or dispersing magnetic colloid particles, polymer monomers and a photoinitiator in a solvent to obtain precursor dispersion liquid;

(2) And (3) applying a magnetic field to the precursor dispersion liquid obtained in the step (1), orderly arranging the magnetic colloid particles under the action of the magnetic field to generate structural color, and then carrying out radiation curing to obtain the structural color binder.

2. The method of preparing a structural color binder according to claim 1, wherein the mass fraction of the magnetic colloid particles in the precursor dispersion is in the range of 1% to 10%.

3. The method for preparing a structural color binder according to claim 1, wherein the magnetic colloidal particles are ferroferric oxide colloidal particles or paramagnetic ferroferric oxide colloidal particles of a coating layer;

preferably, the paramagnetic colloidal particles of the ferroferric oxide coated with the shell layer are ferroferric oxide colloidal particles coated with a silicon dioxide shell layer or ferroferric oxide colloidal particles coated with polyvinylpyrrolidone;

preferably, the size distribution of the magnetic colloidal particles is in the range of 100-400nm.

4. The preparation method of the structural color binder is characterized by comprising the following steps of:

(1) Dispersing non-magnetic colloid particles, polymer monomers and a photoinitiator in a solvent to obtain a dispersion liquid; volatilizing the dispersion liquid in a thermal field in a dark environment to remove the solvent to obtain precursor dispersion liquid with structural color;

(2) And (3) carrying out radiation curing on the precursor dispersion liquid with the structural color obtained in the step (1) to obtain the structural color binder.

5. The method of preparing a structural color binder according to claim 4, wherein the volume fraction of the non-magnetic colloidal particles in the dispersion is in the range of 30% to 80%.

6. The method of producing a structural color binder according to claim 4, wherein the non-magnetic colloidal particles are zirconium dioxide colloidal particles, silica colloidal particles, titania colloidal particles, cerium oxide colloidal particles, zinc sulfide colloidal particles, cellulose nanocrystals, or polymer colloidal particles;

preferably, the polymer colloid particles are polystyrene colloid particles, polydopamine colloid particles or polymethyl methacrylate colloid particles;

preferably, the non-magnetic colloidal particles have a size distribution in the range of 100-400nm.

7. The method of preparing a structural color binder according to any one of claims 1 to 6, wherein the polymer monomer is an acrylate monomer and/or a methacrylate monomer.

8. The structural color adhesive prepared by the method of any one of claims 1-7, wherein the structural color adhesive changes color under the action of an external force and recovers when the external force is removed.

9. The structural color adhesive of claim 8, wherein the external force is tension, compression or shear.

10. Use of a structural color adhesive according to claim 8 or 9 for monitoring adhesive strength changes or stress detection under load.