Amino resin fluorescent microsphere, tracer agent and preparation method of amino resin fluorescent microsphere

Abstract

The invention provides an amino resin fluorescent microsphere, a tracer agent and a preparation method thereof, and the preparation method of the amino resin fluorescent microsphere comprises the following steps: S1, mixing an amino resin prepolymer with an acid catalyst to form a first mixed solution, and carrying out condensation polymerization on the amino resin prepolymer to form an amino resin microsphere; and S2, mixing the amino resin microspheres, fluorescent materials and a catalytic absorbent to form a second mixed solution, and reacting to enable the amino resin microspheres to contain a plurality of fluorescent materials so as to form the amino resin fluorescent microspheres.

Description

Technical Field

[0001] The present application belongs to the technical field of fluorescent microspheres, and specifically relates to amino resin fluorescent microspheres, tracers and preparation methods thereof. Background Art

[0002] Fluorescent microspheres are fluorescent materials coated with a shell layer. The shell layer mainly plays a protective role for the fluorescent material. The shell layer is usually an inorganic shell layer (such as silica) and an organic polymer shell layer (such as polystyrene). Fluorescent materials mainly include: organic fluorescent dyes, quantum dots and metal oxides. These fluorescent materials are easily affected by the environment. For example, they are easy to degrade, easy to be photobleached, not resistant to high temperature / strong light irradiation, not resistant to water and oxygen, etc. Therefore, most of the existing technologies coat the fluorescent materials with an inorganic shell layer or an organic polymer shell layer. Fluorescent materials emit fluorescence when excited by light or electricity. With the help of different fluorescent components and different fluorescent contents, multiple different luminous bands (different colors) can be formed, which has a coding function. Therefore, they are widely used in biomarkers, disease diagnosis, tracers, solid phase chips, liquid phase chips, immunochromatography, Raman scattering and other fields.

[0003] Fluorescent microspheres are used for labeling, tracers, etc. For example, oil field and natural gas tracing requires a large number of fluorescent microspheres with different codes (i.e., different luminous bands / different colors). Since the number of codes of fluorescent microspheres is determined by the luminous band of the fluorescent material and the half-width at half-peak of the fluorescent material, the smaller the half-width at half-peak, the narrower the luminous band of the fluorescent material, that is, the higher the color purity. In order to increase the number of codes of fluorescent microspheres, the prior art achieves this by reducing the half-width at half-peak of the fluorescent material. If the half-width at half-peak of each fluorescent microsphere is reduced, some luminous bands can be added. However, the number of distinguishable luminous bands (coding bands) increased by reducing the half-width at half-peak of the fluorescent material is still limited.

[0004] In view of this, the present application provides an amino resin fluorescent microsphere, a tracer and a preparation method thereof, which can greatly increase the number of codes of the fluorescent microsphere. Summary of the invention

[0005] The purpose of the present application is to provide an amino resin fluorescent microsphere, a tracer and a preparation method thereof, which can greatly increase the number of codes of the fluorescent microsphere.

[0006] In a first aspect of the present application, a method for preparing amino resin fluorescent microspheres is provided, comprising the steps of:

[0007] S1, mixing an amino resin prepolymer and an acidic catalyst to form a first mixed solution, and the amino resin prepolymer undergoes a polycondensation reaction to form amino resin microspheres;

[0008] S2, mixing the amino resin microspheres, fluorescent materials and catalytic absorbent to form a second mixed solution, and reacting the mixture so that the amino resin microspheres contain a plurality of fluorescent materials to form amino resin fluorescent microspheres.

[0009] In some embodiments, in step S1, a first source, a second source, water and an alkaline regulator are mixed to form a premixed solution, and the first source reacts and combines with the second source at a first temperature to form an amino resin prepolymer.

[0010] Furthermore, the first source includes at least one of urea, melamine, or benzoguanamine.

[0011] Furthermore, the second source includes at least one of formaldehyde, paraformaldehyde, or alcohols.

[0012] Furthermore, the alkaline regulator is used to make the pH value of the premixed solution be 7.2-11.

[0013] Furthermore, the premixed liquid also includes a dispersant, which includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, or polyethylene glycol.

[0014] Furthermore, the first temperature is 40-75° C., and the reaction is carried out for 0.5-6 hours at the first temperature and with stirring speed of 200-600 rpm to generate an amino resin prepolymer.

[0015] Furthermore, in the premixed liquid, the molar ratio of the first source to the second source is 1:(1-10), and the mass of the dispersant is 3-30% of the sum of the mass of the first source and the second source.

[0016] In some embodiments, the amino resin prepolymer includes at least one of urea-formaldehyde prepolymer, urea-paraformaldehyde prepolymer, melamine-formaldehyde prepolymer, melamine-paraformaldehyde prepolymer, benzoguanamine-formaldehyde prepolymer, benzoguanamine-paraformaldehyde prepolymer, polyurethane prepolymer, or polyester prepolymer.

[0017] In some embodiments, in the first mixed liquid, the concentration of the acidic catalyst is 0.01-0.3 wt %.

[0018] In some embodiments, the polycondensation reaction is carried out at a temperature of 40-85° C., a time of 1-24 h, and a stirring speed of 100-500 rpm.

[0019] In some embodiments, an acidic catalyst is added to the premixed solution to form a first mixed solution, and after the polycondensation reaction, the premixed solution is centrifuged, washed, and then dried to obtain amino resin microspheres.

[0020] In some embodiments, in step S2, the catalytic absorbent is used to promote the fluorescent material to enter the interior of the amino resin microspheres.

[0021] Furthermore, when the fluorescent material contains a basic group, an acid-catalyzed absorbent is used; when the fluorescent material contains an acidic group, a base-catalyzed absorbent is used.

[0022] Furthermore, the basic group includes at least one of a primary amine, a secondary amine, and a carbon-nitrogen double bond; the acidic group includes at least one of a carboxyl group, a phenol, and a sulfonic acid.

[0023] Furthermore, the fluorescent material containing basic groups includes: at least one of aminomethyl coumarin, neutral red, and quantum dots with amino groups; the fluorescent material containing acidic groups includes: at least one of 8-anilino-1-naphthalenesulfonic acid, fluorescein isothiocyanate, butyl rhodamine, near-infrared anthocyanin, and quantum dots with carboxyl groups.

[0024] In some embodiments, in the second mixed liquid, the concentration of the amino resin microspheres is 20-50 mg / ml, the mass of the fluorescent material is 0.01-1% of the mass of the amino resin microspheres, the mass proportion of the acid catalytic absorbent is 0.1-0.5wt%, and the concentration of the base catalytic absorbent is 2-8mmol / L.

[0025] In some embodiments, the fluorescent material includes at least one of fluorescent nanoparticles, fluorescent polymers, and organic fluorescent dyes, and the fluorescent nanoparticles include at least one of quantum dots, metal oxide nanoparticles, nanorods, or nanosheets.

[0026] In some embodiments, amino resin microspheres are mixed with water, and then a catalytic absorbent is added, and then a fluorescent material dissolved in an organic solvent is added, and the mixture is reacted at a temperature of 55-85° C. and a stirring speed of 100-500 rpm for 1-24 hours to form amino resin fluorescent microspheres.

[0027] In some embodiments, the surface of the amino resin fluorescent microspheres obtained in step S2 is coated with a shell layer, and the shell layer includes an inorganic shell layer or an organic shell layer.

[0028] In a second aspect of the present application, an amino resin fluorescent microsphere is provided. The amino resin fluorescent microsphere is obtained by using the above-mentioned preparation method of the amino resin fluorescent microsphere.

[0029] The third aspect of the present application provides a method for preparing a tracer, the method comprising the above-mentioned step S1 and step S2, and the step:

[0030] S3, connecting the amino resin fluorescent microspheres to the functional groups.

[0031] In some embodiments, when the functional group is a hydrophilic functional group and a coupling functional group, the tracer is a biological tracer; when the functional group is a hydrophilic functional group, the tracer is an aqueous phase tracer; when the functional group is a lipophilic functional group, the tracer is an oil phase tracer.

[0032] In a fourth aspect of the present application, a tracer is provided, wherein the tracer is obtained by using the preparation method of the aforementioned tracer.

[0033] Compared with the prior art, the amino resin fluorescent microspheres, tracers and preparation methods thereof of the present application have at least the following advantages:

[0034] (1) In the present application, no fluorescent material is added during the polycondensation reaction of the amino resin prepolymer. Without the influence of the fluorescent material, the particle size of the formed amino resin microspheres (commonly known as white balls) can be regulated within a larger particle size range, thereby increasing the dimension of particle size for fluorescent microsphere encoding; and the particle size of the synthesized amino resin microspheres is uniform.

[0035] (2) In the present application, since the amino resin microspheres have abundant pores, in step S2, a large amount of fluorescent material is drawn into the interior of the amino resin microspheres through the action of catalysis (the fluorescent material is drawn and accumulated in large quantities in the abundant pores of the amino resin microspheres), so that the fluorescence intensity of the amino resin fluorescent microspheres can reach a very high level, thereby increasing the dimension of fluorescence intensity to encode the fluorescent microspheres.

[0036] (3) In the present application, for fluorescent materials containing basic groups, an acid catalytic absorbent is used to promote the reaction rate (the reaction is extremely slow under non-acidic conditions), so that a large amount of fluorescent materials containing basic groups react and connect with the interior of amino resin microspheres. For fluorescent materials containing acidic groups, a base catalytic absorbent is used to activate the fluorescent materials containing acidic groups to form ionic forms, so that a large amount of fluorescent materials containing acidic groups are electrostatically adsorbed with the interior of amino resin microspheres. As a result, a large amount of fluorescent materials enter the rich pores inside the amino resin microspheres, that is, the interior of the amino resin microspheres contains a large amount of fluorescent materials, forming amino resin fluorescent microspheres.

[0037] (4) The present application may also coat the surface of the amino resin fluorescent microspheres obtained in step S2 with a shell layer, wherein the shell layer includes an inorganic shell layer or an organic shell layer. The shell layer can better protect the fluorescent material or increase other properties (such as bioaffinity, introduction of other reactive groups, etc.). DETAILED DESCRIPTION

[0038] The following examples are described to assist the understanding of the present application, and the examples are not and should not be interpreted in any way as limiting the scope of protection of the present application.

[0039] If not otherwise defined, all terms (including technical and scientific terms) in this specification may be defined as commonly understood by those skilled in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the present disclosure and the relevant art, and will be interpreted in a non-idealized or overly formal sense unless clearly defined as such in this article.

[0040] As used herein, the term "at least one", when before or after a list of elements, modifies the entire list of elements without modifying the individual elements of the list, and will not be interpreted as limiting "one". "Or" means "and / or". The terms "include" and "comprise", when used in this specification, indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or their collections. Therefore, the above wording will be understood to mean including the stated elements, but not excluding any other elements. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "multiple" refers to two or more. The term "connection" refers to direct or indirect connection. It will be understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, it may be directly on the other element or there may also be an intermediate element. On the contrary, when an element is referred to as "directly on" another element, there is no intermediate element. In order to clearly describe the embodiments, some parts that are not actually related to the description may be omitted. The terms "first", "second", "third", etc. may be used herein to describe and distinguish various elements, components, regions, layers and / or parts, but these elements, components, regions, layers and / or parts should not be limited by these terms.

[0041] In a first aspect of the present application, a method for preparing amino resin fluorescent microspheres is provided, comprising the steps of:

[0042] S1, mixing an amino resin prepolymer and an acidic catalyst to form a first mixed solution, and the amino resin prepolymer undergoes a polycondensation reaction to form amino resin microspheres;

[0043] S2, mixing the amino resin microspheres, fluorescent materials and catalytic absorbent to form a second mixed solution, and reacting the mixture so that the amino resin microspheres contain a plurality of fluorescent materials to form amino resin fluorescent microspheres.

[0044] In some embodiments, in step S1, a first source, a second source, water and an alkaline regulator are mixed to form a premixed solution, and the first source reacts and combines with the second source at a first temperature to form an amino resin prepolymer.

[0045] Furthermore, the first source includes at least one of urea, melamine, or benzoguanamine.

[0046] Furthermore, the second source includes at least one of formaldehyde, paraformaldehyde, or alcohols. In addition to the sources (precursors) for synthesizing amino resins listed above, other sources for synthesizing amino resins are also within the protection scope of this application.

[0047] Further, the alkaline regulator is used to make the pH value of the premixed solution 7.2-11. The alkaline regulator includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, phosphate buffer, or borate buffer. In addition to the alkaline regulators listed, other alkaline regulators are also within the scope of protection of this application.

[0048] Furthermore, the premixed liquid further comprises: a dispersant. The dispersant comprises: at least one of polyvinyl pyrrolidone, polyvinyl alcohol, or polyethylene glycol. In addition to the above-mentioned dispersants, other ingredients capable of dispersing are also within the scope of protection of this application.

[0049] Further, the first temperature is 40-75°C, for example 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, or 75°C, but not limited to the listed values, and other values ​​not listed in the above range are also applicable. At the first temperature, stirring at a speed of 200-600rpm, for example 200rpm, 250rpm, 300rpm, 350rpm, 400rpm, 450rpm, 500rpm, 550rpm, or 600rpm, but not limited to the listed values, and other values ​​not listed in the above range are also applicable. The reaction is carried out for 0.5-6h, for example 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, or 6h, but not limited to the listed values, and other values ​​not listed in the above range are also applicable to generate an amino resin prepolymer.

[0050] Further, in the premix, the molar ratio of the first source to the second source is 1:(1-10), for example 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10, but is not limited to the listed values, and other unlisted values ​​within the above range are equally applicable. The mass of the dispersant is 3-30% of the sum of the masses of the first source and the second source, for example 3%, 5%, 8%, 10%, 13%, 15%, 17%, 20%, 23%, 25%, 27%, or 30%, but is not limited to the listed values, and other unlisted values ​​within the above range are equally applicable.

[0051] Preferably, in the premixed liquid, the molar ratio of the first source to the second source is 1:(3-6), and the mass of the dispersant is 10-20% of the sum of the mass of the first source and the second source.

[0052] In some embodiments, the amino resin prepolymer includes at least one of urea-formaldehyde prepolymer, urea-paraformaldehyde prepolymer, melamine-formaldehyde prepolymer, melamine-paraformaldehyde prepolymer, benzoguanamine-formaldehyde prepolymer, benzoguanamine-paraformaldehyde prepolymer, polyurethane prepolymer, or polyester prepolymer.

[0053] In some embodiments, in the first mixed solution, the concentration of the acidic catalyst is 0.01-0.3wt%, such as 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0. 15wt%, 0.16wt%, 0.17wt%, 0.18wt%, 0.19wt%, 0.2wt%, 0.21wt%, 0.22wt%, 0.23wt%, 0.24wt%, 0.25wt%, 0.26wt%, 0.27wt%, 0.28wt%, 0.29wt%, or 0.3wt%, but not limited to the listed values, other unlisted values ​​within the above range are also applicable.

[0054] Preferably, in the first mixed solution, the concentration of the acidic catalyst is 0.05-0.25wt%. The acidic catalyst includes at least one of hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, or formic acid. In addition to the listed acidic regulator components, other acidic regulator components can also play a catalytic role and are also within the scope of protection of this application.

[0055] In some embodiments, the temperature of the polycondensation reaction is 40-85°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or 85°C, but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable, and the time is 1-24h, such as 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h. The stirring speed is 100-500 rpm, for example 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm, but is not limited to the listed values, and other values ​​not listed in the above range are also applicable.

[0056] Preferably, the polycondensation reaction temperature is 55-75°C, the time is 2-20h, and the stirring speed is 150-250rpm.

[0057] In some embodiments, an acidic catalyst is added to the premixed solution to form a first mixed solution, and after the polycondensation reaction, the premixed solution is centrifuged, washed, and then dried to obtain amino resin microspheres.

[0058] The amino resin prepolymer undergoes a polycondensation reaction under the action of an acidic catalyst to form amino resin microspheres. Specifically, the amino resin prepolymer begins to polycondense under the catalysis of an acid to produce primary particles of amino resin microspheres. Since the surface of the primary particles contains a large number of -NH2 and -NH groups, the primary particles then continue to undergo a polycondensation reaction with the amino resin prepolymer in the reaction system until the amino resin prepolymer is consumed, and the primary particles gradually grow into amino resin microspheres. Since the amino resin is a porous structure, there are gaps / channels between the pores, thus forming abundant pores. In this process, the particle size of the amino resin microspheres can be controlled by adjusting factors such as the mass proportion of the dispersant, the concentration of the acidic catalyst, and the time of the polycondensation reaction.

[0059] In the prior art, amino resin fluorescent microspheres are synthesized by adding fluorescent materials to the first mixed solution, that is, amino resin prepolymers, fluorescent materials, and acidic catalysts are subjected to polycondensation reaction, and amino resin prepolymers are attached to primary particles of amino resin microspheres on the surface of fluorescent materials, gradually forming amino resin fluorescent microspheres coated with multiple fluorescent materials. However, since fluorescent materials such as organic fluorescent dyes and quantum dots are basically equivalent to a buffer system, the pH of the reaction system is always within a small range, so it is difficult for the particle size of the synthesized amino resin fluorescent microspheres to change significantly; and since the fluorescent material is wrapped by the microspheres in a uniformly dispersed manner, the content of fluorescent materials inside the synthesized amino resin fluorescent microspheres is low, the fluorescence intensity is weak, and the particle size of the amino resin fluorescent microspheres is also uneven.

[0060] However, in the present application, when the amino resin prepolymer undergoes polycondensation reaction, no fluorescent material is added, and without the influence of the fluorescent material, the particle size of the formed amino resin microspheres (commonly known as white balls) can be regulated within a larger particle size range, so as to increase the fluorescent microsphere encoding through the dimension of particle size; and the particle size of the synthesized amino resin microspheres is uniform. Then, because the amino resin microspheres have abundant pores, in step S2, a large amount of fluorescent materials are pulled into the interior of the amino resin microspheres (the fluorescent materials are pulled and gathered in large quantities in the abundant pores of the amino resin microspheres) through the action of catalysis, so that the fluorescence intensity of the amino resin fluorescent microspheres can reach a very high level, so as to increase the fluorescent microsphere encoding through the dimension of fluorescence intensity. Compared with the amino resin fluorescent microspheres of the prior art, in addition to being able to encode fluorescent microspheres through fluorescent color (fluorescence emission peak band), the present application also realizes the encoding of fluorescent microspheres through the two dimensions of particle size and fluorescence intensity, which greatly improves the number of codes.

[0061] In some embodiments, in step S2, the catalytic absorbent is used to promote the fluorescent material to enter the interior of the amino resin microspheres.

[0062] Furthermore, when the fluorescent material contains a basic group, an acid-catalyzed absorbent is used; when the fluorescent material contains an acidic group, a base-catalyzed absorbent is used.

[0063] Furthermore, the basic group includes at least one of a primary amine, a secondary amine, and a carbon-nitrogen double bond, and the acidic group includes at least one of a carboxyl group, a phenol, and a sulfonic acid.

[0064] Further, the fluorescent material containing basic groups includes: at least one of aminomethylcoumarin (AMC), neutral red (NR), and quantum dots with amino groups; the fluorescent material containing acidic groups includes: at least one of 8-anilino-1-naphthalenesulfonic acid (ANS), fluorescein isothiocyanate (FIFC), butyl rhodamine (RDB), near-infrared anthocyanin (CY7), and quantum dots with carboxyl groups. In addition to these listed components, other fluorescent materials containing acidic groups, acidic groups, and other fluorescent materials containing basic groups and alkaline groups are also within the scope of protection of this application.

[0065] Furthermore, the acid catalytic absorbent includes at least one of hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, or formic acid.

[0066] Further, the base catalytic absorbent includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, phosphate buffer, or borate buffer. In addition to the acid catalytic absorbents and base catalytic absorbents listed above, other acidic or alkaline catalysts are also within the scope of protection of this application.

[0067] The basic groups or acidic groups contained in the fluorescent material, whether they are inherent in the fluorescent material or additionally modified on the fluorescent material, are all applicable to the present application.

[0068] If no catalytic absorbent is added, a relatively small amount of fluorescent material containing acidic groups can enter the pores inside the amino resin microspheres only through electrostatic adsorption; only a small amount of fluorescent material containing basic groups can enter the amino resin microspheres. In the present application, for fluorescent materials containing basic groups, an acid catalytic absorbent is used to promote the reaction rate (the reaction is extremely slow under acidic conditions), so that a large amount of fluorescent materials containing basic groups are reacted and connected with the inside of the amino resin microspheres. For fluorescent materials containing acidic groups, a base catalytic absorbent is used to activate the fluorescent materials containing acidic groups to form ionic forms, so that a large amount of fluorescent materials containing acidic groups are electrostatically adsorbed with the inside of the amino resin microspheres. As a result, a large amount of fluorescent materials enter the rich pores inside the amino resin microspheres, that is, a large amount of fluorescent materials are contained inside the amino resin microspheres, forming amino resin fluorescent microspheres.

[0069] In some embodiments, in the second mixed solution, the concentration of the amino resin microspheres is 20-50 mg / ml, such as 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, 45 mg / ml, or 50 mg / ml, but not limited to the listed values, and other values ​​not listed in the above range are also applicable. The mass of the fluorescent material is 0.01-1% of the mass of the amino resin microspheres, such as 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%, but not limited to the listed values, and other values ​​not listed in the above range are also applicable. The mass proportion of the acid catalytic absorbent is 0.1-0.5wt% , for example, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt%, or 0.5wt%, but not limited to the listed values, other values ​​not listed in the above range are also applicable, the concentration of the base catalyzed absorbent is 2-8mmol / L, for example 2mmol / L, 2.5mmol / L, 3mmol / L, 3.5mmol / L, 4mmol / L, 4.5mmol / L, 5mmol / L, 5.5mmol / L, 6mmol / L, 6.5mmol / L, 7mmol / L, 7.5mmol / L, or 8mmol / L, but not limited to the listed values, other values ​​not listed in the above range are also applicable.

[0070] Preferably, in the second mixed solution, the concentration of the amino resin microspheres is 20-40 mg / ml, the mass of the fluorescent material is 0.05-0.6% of the amino resin microspheres, the mass proportion of the acid catalytic absorbent is 0.1-0.3wt%, and the concentration of the base catalytic absorbent is 3-5mmol / L.

[0071] In some embodiments, the fluorescent material includes at least one of fluorescent nanoparticles, fluorescent polymers, and organic fluorescent dyes, and the fluorescent nanoparticles include at least one of quantum dots, metal oxide nanoparticles, nanorods, or nanosheets.

[0072] The quantum dots include: at least one of group IIB-VIA quantum dots, group IIIA-VA quantum dots, group IVA-VIA quantum dots, group IVA quantum dots, group IB-IIIA-VIA quantum dots, group IB-IIB-IVA-VIA quantum dots, group VIII-VIA quantum dots, perovskite quantum dots and carbon quantum dots (carbon dots). For example, group IIB-VIA quantum dots include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdS eS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZn Te, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS , CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe or combinations thereof. For example, Group IIIA-VA quantum dots include: GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, InZnP, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or combinations thereof. For example, IVA-VIA group quantum dots include: SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe or a combination thereof. For example, IVA group quantum dots include: Si, Ge, SiC, SiGe or a combination thereof. For example, IB-IIIA-VIA group quantum dots include: CuInSe2, CuInS2, CuInGaSe, CuInGaS or a combination thereof. For example, IB-IIB-IVA-VIA group quantum dots include: CuZnSnSe, CuZnSnS or a combination thereof.For example, the general structural formula of perovskite quantum dots is one of ABX3, A2B2X6, and A3B3X9, wherein A is a monovalent amine organic cation or a monovalent inorganic metal cation (such as CH3NH3. + 、NH2CHNH2+、C(NH2)3 + , Cs + , Li + 、Na + , K + , Rb + , aromatic groups, etc.), B is a divalent inorganic metal cation (such as a divalent cation of a rare earth metal, a divalent cation of an alkaline earth metal, a divalent cation of a transition metal, a divalent cation of a post-transition metal, etc.), and X is a monovalent anion (such as a halogen, etc.). For example, carbon quantum dots are carbon sources such as organic acids, and are carbonized under high temperature conditions such as microwave ovens or heating to form carbon quantum dots with a particle size of about 10 nm. Most carbon quantum dots are mainly composed of amorphous carbon to a crystallized carbon core with a sp 2 Hybridized carbon. These components are usually the core components of quantum dots, and quantum dots usually also include one or more shells (the outer shell is usually ZnS) that wrap the core. In addition to the quantum dots listed above, other common quantum dots are also applicable to the present application and are within the scope of protection of the present application. The metal oxides of the metal oxide nanoparticles include: Zn, Cr, Co, Dy, Er, Eu, Fe, Gd, Gd, Pr, Nd, Ni, In, Pr, Sm, Tb, Tm, and combinations thereof. The structure of the fluorescent polymer has a functional group that can emit fluorescence (such as fluorescein, etc.) and a monomer that can undergo polymerization reaction. The monomers are polymerized with each other or with other monomers that do not contain fluorescence, thereby preparing a fluorescent polymer. Organic fluorescent dyes include: fluoresceins (stilbenes, coumarins, fluorans, benzoxazoles, naphthalene diimides, thiophene dicarboxylic acid amides, condensed aromatic hydrocarbons, perylene tetracarboximide, etc.), aromatic condensed ring compounds, intramolecular charge transfer compounds, metal complex fluorescent materials, enzymes, and rare earth metal chelates.

[0073] In some embodiments, the amino resin microspheres are mixed with water, and then a catalytic absorbent is added, and then a fluorescent material dissolved in an organic solvent is added, and the reaction is carried out at a temperature of 55-85°C, such as 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or 85°C, but not limited to the values ​​listed, and other values ​​not listed in the above range are also applicable, and the reaction is carried out at a stirring speed of 100-500 rpm for 1-24 hours, such as 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm m, 400rpm, 450rpm, or 500rpm, but not limited to the listed values, other values ​​not listed in the above range are also applicable, for example, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, or 24h, but not limited to the listed values, other values ​​not listed in the above range are also applicable to form amino resin fluorescent microspheres.

[0074] Preferably, the amino resin microspheres are mixed with water, and then a catalytic absorbent is added, and then a fluorescent material dissolved in an organic solvent is added, and the mixture is reacted at a temperature of 60-80° C. and a stirring speed of 150-250 rpm for 10-20 hours to form amino resin fluorescent microspheres.

[0075] In some embodiments, the surface of the amino resin fluorescent microspheres obtained in step S2 is coated with a shell layer, and the shell layer includes an inorganic shell layer or an organic shell layer.

[0076] Based on the amino resin fluorescent microspheres obtained in step S2 of the present application, a shell layer can be coated on the surface thereof, wherein the shell layer is an organic shell layer or an inorganic shell layer, such as a silica shell layer, a titanium dioxide shell layer, etc., and an organic shell layer is a polymer shell layer such as polystyrene, polyacrylic acid, etc. Coating the shell layer can better protect the fluorescent material in the amino resin fluorescent microspheres from being affected by adverse factors such as water, oxygen, high temperature, strong acid, strong alkali, etc., and prevent the fluorescent material in the amino resin fluorescent microspheres from leaking out under specific conditions, etc., so that the amino resin fluorescent microspheres have other characteristics, such as bioaffinity, such as introducing other groups to enable further reaction or connection with other components on their surface, etc.

[0077] In a second aspect of the present application, an amino resin fluorescent microsphere is provided. The amino resin fluorescent microsphere is obtained by using the above-mentioned preparation method of the amino resin fluorescent microsphere.

[0078] The third aspect of the present application provides a method for preparing a tracer, the method comprising the above-mentioned step S1 and step S2, and the step:

[0079] S3, connecting the amino resin fluorescent microspheres to the functional groups.

[0080] In some embodiments, when the functional group is a hydrophilic functional group and a coupling functional group, the tracer is a biological tracer; when the functional group is a hydrophilic functional group, the tracer is an aqueous phase tracer; when the functional group is a lipophilic functional group, the tracer is an oil phase tracer.

[0081] The surface of amino resin fluorescent microspheres has hydrophilic groups, which can be used directly as water phase tracers, or modified with other hydrophilic groups. As for oil phase tracers, amino resin fluorescent microspheres need to be transferred to the oil phase by surface modification or surface coating. If the tracer needs to have a sustained release effect, the tracer can be further prepared as a coated sand sustained release tracer or a sustained release tracer tape.

[0082] The hydrophilic functional groups include at least one of carboxyl, phosphate, amino, imino, quaternary ammonium, amide, ether, hydroxyl and aldehyde. The lipophilic functional groups include hydrocarbon, ester, aromatic, polyoxybutylene, long-chain perfluoroalkyl and polysiloxane. The coupling functional groups include amino, carboxyl, epoxy, azido and aldehyde.

[0083] The components containing hydrophilic functional groups include: at least one of acrylic acid, methacrylic acid, polyacrylic acid, polymethacrylic acid, itaconic acid and maleic acid. The components containing coupling functional groups include: at least one of glycidyl methacrylate, allyl glycidyl ether, epoxy polyethylene glycol acrylate, epoxy polyethylene glycol methacrylate, azido polyethylene glycol acrylate, azido polyethylene glycol methacrylate, aldehyde polyethylene glycol acrylate, aldehyde polyethylene glycol methacrylate, 4,4'-diazide stilbene-2,2'-disulfonic acid disodium tetrahydrate, acrolein, trans-2-pentenal, 3-(2-furanyl) acrolein, 3-dimethylamino acrolein, 2-methyl acrolein and cinnamaldehyde. The components containing lipophilic functional groups include: at least one of polydimethylsiloxane, trivinyl chlorosilane, hexadecane oxide, tetradecane oxide, hexadecane, octadecane, and chloropolystyrene.

[0084] The tracer can be directly put into groundwater or oil fields, or further prepared as a coated sand tracer (i.e., the tracer and the slow-release material are coated on the surface of quartz sand or the like to achieve a slow-release effect), or further prepared as a tracer tape (i.e., the tracer and the slow-release material are adhered and fixed on a carrier such as a metal mesh, and the tracer tape can be placed in a tracer screen).

[0085] In a fourth aspect of the present application, a tracer is provided, wherein the tracer is obtained by using the preparation method of the aforementioned tracer.

[0086] In some embodiments, when the functional groups modified by the amino resin fluorescent surface are hydrophilic functional groups and coupling functional groups, the tracer is a biological tracer. Applications of biological tracers include: drug loading, biological probes, biomarkers, disease diagnosis, solid phase chips, liquid phase chips, and Raman scattering. When the amino resin fluorescent surface is modified by hydrophilic functional groups, the tracer is a water phase tracer. For example, it is used for groundwater tracing, oil-water mixture tracing, etc. When the amino resin fluorescent surface is modified by lipophilic functional groups, the tracer is an oil phase tracer. For example, it is used for petroleum tracing, oil-water mixture tracing, etc.

[0087] The present invention will be further described in detail below in conjunction with specific embodiments and comparative examples, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the unspecified conditions are conventional conditions in the industry.

[0088] Embodiment 1:

[0089] Step S1: Preparation of amino resin microspheres

[0090] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 0.5g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 0.2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0091] Step S2: Preparation of amino resin fluorescent microspheres

[0092] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 80mg phosphoric acid (phosphoric acid concentration 85%). Dissolve 6mg aminomethylcoumarin (AMC) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0093] Embodiment 2:

[0094] Example 2 is substantially the same as Example 1, except that in step S2, 6 mg of aminomethylcoumarin (AMC) is replaced with 6 mg of neutral red (NR).

[0095] Embodiment 3:

[0096] Step S1: Preparation of amino resin microspheres

[0097] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 0.5g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 0.2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0098] Step S2: Preparation of amino resin fluorescent microspheres

[0099] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 5.6mg sodium hydroxide. Dissolve 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0100] Embodiment 4:

[0101] Example 4 is substantially the same as Example 3, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of fluorescein isothiocyanate (FIFC).

[0102] Embodiment 5:

[0103] Example 5 is substantially the same as Example 3, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of butyl rhodamine (RDB).

[0104] Embodiment 6:

[0105] Example 6 is substantially the same as Example 3, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of near-infrared anthocyanidin (CY7).

[0106] Embodiment 7:

[0107] Step S1: Preparation of amino resin microspheres

[0108] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0109] Step S2: Preparation of amino resin fluorescent microspheres

[0110] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 80mg phosphoric acid (phosphoric acid concentration 85%). Dissolve 6mg aminomethylcoumarin (AMC) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0111] Embodiment 8:

[0112] Example 8 is substantially the same as Example 7, except that in step S2, 6 mg of aminomethylcoumarin (AMC) is replaced with 6 mg of neutral red (NR).

[0113] Embodiment 9:

[0114] Step S1: Preparation of amino resin microspheres

[0115] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0116] Step S2: Preparation of amino resin fluorescent microspheres

[0117] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 5.6mg sodium hydroxide. Dissolve 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0118] Embodiment 10:

[0119] Example 10 is substantially the same as Example 9, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of fluorescein isothiocyanate (FIFC).

[0120] Embodiment 11:

[0121] Example 11 is substantially the same as Example 9, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of butyl rhodamine (RDB).

[0122] Embodiment 12:

[0123] Example 12 is substantially the same as Example 9, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of near-infrared anthocyanidin (CY7).

[0124] Embodiment 13:

[0125] Step S1: Preparation of amino resin microspheres

[0126] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0127] Step S2: Preparation of amino resin fluorescent microspheres

[0128] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 80mg phosphoric acid (phosphoric acid concentration 85%). Dissolve 6mg aminomethylcoumarin (AMC) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0129] Embodiment 14:

[0130] Example 14 is substantially the same as Example 13, except that in step S2, 6 mg of aminomethylcoumarin (AMC) is replaced with 6 mg of neutral red (NR).

[0131] Embodiment 15:

[0132] Step S1: Preparation of amino resin microspheres

[0133] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0134] Step S2: Preparation of amino resin fluorescent microspheres

[0135] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C, then add 5.6mg sodium hydroxide. Dissolve 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0136] Embodiment 16:

[0137] Example 16 is basically the same as Example 15, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of fluorescein isothiocyanate (FIFC).

[0138] Embodiment 17:

[0139] Example 17 is substantially the same as Example 15, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of butyl rhodamine (RDB).

[0140] Embodiment 18:

[0141] Example 18 is substantially the same as Example 15, except that in step S2, 6 mg of 8-anilino-1-naphthalenesulfonic acid (ANS) is replaced with 6 mg of near-infrared anthocyanidin (CY7).

[0142] Comparative Example 1:

[0143] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 0.5g polyvinyl pyrrolidone (PVP), 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath, stir at 250rpm for 1h, and the solution becomes transparent. Keep the water bath at 65°C, then add 0.2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) and 6mg neutral red (NR) to the three-necked flask, and stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin fluorescent microspheres.

[0144] Comparative Example 2:

[0145] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) and 6mg neutral red (NR) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin fluorescent microspheres.

[0146] Comparative Example 3:

[0147] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 0.5g polyvinylpyrrolidone (PVP), 100ml deionized water at room temperature (25℃) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65℃ water bath, stir at 250rpm for 1h, and the solution becomes transparent. Keep the water bath at 65℃, then add 0.2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) and 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) in the three-necked flask, stir at 250rpm for 16h. Centrifuge, wash twice, and then dry to obtain amino resin fluorescent microspheres.

[0148] Comparative Example 4:

[0149] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinylpyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) and 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin fluorescent microspheres.

[0150] Comparative Example 5:

[0151] Step S1: Preparation of amino resin microspheres

[0152] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0153] Step S2: Preparation of amino resin fluorescent microspheres

[0154] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C. Dissolve 6mg neutral red (NR) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0155] Comparative Example 6:

[0156] Step S1: Preparation of amino resin microspheres

[0157] In a 250ml three-necked flask, add 2.6g melamine, 3.7g paraformaldehyde, 1g polyvinyl pyrrolidone (PVP), and 100ml deionized water at room temperature (25°C) and mix well, then add 2.5ml sodium hydroxide aqueous solution (sodium hydroxide concentration is 0.1mMol / L). Place the three-necked flask in a 65°C water bath and stir at 250rpm for 1h. The solution is transparent. Keep the water bath at 65°C, then add 2ml phosphoric acid aqueous solution (phosphoric acid concentration is 8.5%) to the three-necked flask and stir at 250rpm for 3h. Centrifuge, wash twice, and then dry to obtain amino resin microspheres.

[0158] Step S2: Preparation of amino resin fluorescent microspheres

[0159] In a 100ml three-necked flask, add 1.2g amino resin microspheres and 40ml deionized water at room temperature (25°C) and mix well; heat to 70°C. Dissolve 6mg 8-anilino-1-naphthalenesulfonic acid (ANS) in 1ml dimethyl sulfoxide (DMSO), then add to the three-necked flask, keep stirring at 70°C and 250rpm for 16h to obtain amino resin fluorescent microspheres.

[0160] The amino resin fluorescent microspheres prepared in the above Examples 1-18 and Comparative Examples 1-6 were washed three times with water, dispersed in water, and diluted with water so that the concentration of the amino resin fluorescent microspheres was 0.001 mg / ml. The average particle size, particle size variation coefficient (particle size CV%) and fluorescence brightness were detected by flow cytometry. The detection data are shown in Table 1.

[0161] Table 1: Statistics of average particle size, particle size CV and fluorescence brightness of Examples 1-18 and Comparative Examples 1-6.

[0162] sample Detection channel Average particle size μm Particle size CV% Fluorescence brightness Example 1 450 5.48 9.87 4238448 Example 2 660 5.46 9.96 8940970 Example 3 V525 5.48 10.03 1741134 Example 4 B525 5.42 10.12 8319659 Example 5 585 5.54 10.11 4448605 Example 6 780 5.49 9.97 2436771 Example 7 450 3.73 9.86 2039739 Example 8 660 3.78 10.08 5053658 Example 9 V525 3.62 9.98 1402536 Example 10 B525 3.65 10.23 4803526 Embodiment 11 585 3.70 10.19 2355662 Example 12 780 3.65 9.88 1753751 Example 13 450 2.26 9.78 919384 Embodiment 14 660 2.28 9.96 2021315 Embodiment 15 V525 2.23 9.90 636826 Example 16 B525 2.18 10.13 2032348 Embodiment 17 585 2.15 10.18 1037248 Embodiment 18 780 2.17 9.86 669063 Comparative Example 1 660 2.31 50.12 356178 Comparative Example 2 660 1.55 24.99 222765 Comparative Example 3 V525 2.43 49.87 152487 Comparative Example 4 V525 1.91 25.17 98751 Comparative Example 5 660 2.23 9.99 870184 Comparative Example 6 V525 2.25 10.18 226428

[0163] As can be seen from Table 1, compared with Examples 1-6, Examples 7-12, and Examples 13-18, the present application forms amino resin fluorescent microspheres of about 5.5 um, about 3.7 um, and about 2.2 um, respectively, by adjusting the synthesis conditions (such as dispersant concentration, acid catalyst concentration, reaction time, etc.) in step S1. The particle size span of the amino resin fluorescent microspheres is relatively large, that is, the particle size adjustable range of the amino resin fluorescent microspheres is relatively large. The concentration of each component and the reaction time of Comparative Example 1 (NR is a fluorescent material containing a basic group) are basically the same as those of Example 2, but the particle size of the synthesized amino resin fluorescent microspheres is 2.31um by adopting the synthesis method of the prior art; the concentration of each component and the reaction time of Comparative Example 2 are basically the same as those of Example 14, but the particle size of the synthesized amino resin fluorescent microspheres is 1.55um by adopting the synthesis method of the prior art; at the same time, the particle sizes of the synthesized amino resin fluorescent microspheres of Comparative Examples 3 and Comparative Examples 4 (ANS is a fluorescent material containing an acidic group) are 2.43um and 1.91um respectively compared with Examples 3 and 15; that is, by adopting the synthesis method of the prior art, the particle size of the amino resin fluorescent microspheres can only be regulated within a smaller range. The technical solution of the present application, for example, amino resin fluorescent microspheres containing the same fluorescent material can synthesize multiple (at least 3-5) standard particle sizes, so the number of codes can be correspondingly increased by at least 2-4 times, realizing the increase of the coding dimension of the particle size.

[0164] In the case where the particle size is not much different, for example, when comparing Comparative Example 1 with Example 14 (the fluorescent material is the same as NR), the fluorescent brightness of Example 14 is about 2 million, and the fluorescent brightness of Comparative Example 1 is about 350,000; when comparing Comparative Example 3 with Example 15 (the fluorescent material is the same as ANS), the fluorescent brightness of Example 15 is about 630,000, and the fluorescent brightness of Comparative Example 3 is about 150,000; it can be seen that the fluorescent brightness of the amino resin fluorescent microspheres synthesized by the technical solution of the present application has been significantly improved. The fluorescent brightness of Examples 1-6 is between 1.7 million and 8.9 million. For example, amino resin fluorescent microspheres containing the same fluorescent material and the same particle size can reduce the fluorescent brightness by reducing the amount of fluorescent material added during synthesis (in Examples 1-18, sufficient fluorescent material is added), such as 8 million, 4 million, 2 million, 1 million, 500,000, 250,000, 120,000, 60,000, 30,000, 10,000, etc. for encoding, and the encoding dimension of fluorescent brightness can be increased, thereby greatly increasing the number of codes.

[0165] At the same time, compared with Examples 1-6, Examples 7-12, and Examples 13-18, the average particle size is stable, which is about 5.5um, about 3.7um, and about 2.2um, respectively, and the particle size fluctuation range of the amino resin fluorescent microspheres in the same batch or different batches is small, that is, the particle size is uniform, and the particle size CV value is about 10%. The particle size fluctuation range is small, which is conducive to improving the detection accuracy. Compared with Comparative Example 1 and Comparative Example 2, and Comparative Example 3 and Comparative Example 4, Comparative Example 1 and Comparative Example 3 are equivalent to almost reaching the limit of particle size regulation, and their particle size CV values ​​are about 50%. The particle size fluctuation range is extremely large and cannot be put into practical use; and the particle size CV values ​​of Comparative Example 2 and Comparative Example 4 are also relatively large, which is about 25%. In other words, while adding two coding dimensions (particle size and fluorescence intensity), the present application can further improve the particle size uniformity of amino resin fluorescent microspheres.

[0166] The present application first synthesizes amino resin microspheres and then draws in fluorescent materials to form amino resin fluorescent microspheres. On the basis of this technical solution, the present application is further optimized by adding a catalytic absorbent to promote the fluorescent material to enter the interior of the amino resin microspheres, thereby further improving the fluorescence brightness / intensity of the amino resin fluorescent microspheres. For example, in Comparative Example 5 compared with Example 14, and Comparative Example 6 compared with Example 15, the synthesis conditions are basically the same except that the catalytic absorbent is not added. The fluorescence brightness of the amino resin fluorescent microspheres synthesized in Examples 14 and 15 is increased by about 2.5-3 times relative to Comparative Examples 5 and 6. It can be seen that the addition of a catalytic absorbent can greatly improve the fluorescence brightness of the synthesized amino resin fluorescent microspheres. At the same time, in Comparative Example 5 compared with Comparative Examples 1-2, and Comparative Example 6 compared with Comparative Examples 3-4, the technical solution of the present application is compared with the prior art synthesis method, and even if the catalytic absorbent is not added, the fluorescence brightness of the synthesized amino resin fluorescent microspheres is significantly higher than that of the prior art.

[0167] Although the present application has disclosed multiple aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art, and several modifications and improvements may be made without departing from the concept of the present application, all of which belong to the protection scope of the present application. The multiple aspects and embodiments disclosed in the present application are only for illustration and are not intended to limit the present application. The actual protection scope of the present application shall be subject to the claims.

Claims

1. A method for preparing amino resin fluorescent microspheres, characterized in that: Includes steps: S1, mixing an amino resin prepolymer and an acidic catalyst to form a first mixed solution, and the amino resin prepolymer undergoes a polycondensation reaction to form amino resin microspheres; S2, mixing the amino resin microspheres, fluorescent materials and catalytic absorbent to form a second mixed solution, and reacting the mixture so that the amino resin microspheres contain a plurality of fluorescent materials to form amino resin fluorescent microspheres.

2. The method for preparing amino resin fluorescent microspheres according to claim 1, characterized in that: In step S1, a first source, a second source, water and an alkaline regulator are mixed to form a premixed solution. At a first temperature, the first source reacts and combines with the second source to form an amino resin prepolymer.

3. The method for preparing amino resin fluorescent microspheres according to claim 2, characterized in that: Includes one or more features selected from the following group: (1) The first source includes at least one of urea, melamine, or benzoguanamine; (2) the second source comprises at least one of formaldehyde, paraformaldehyde, or alcohols; (3) the alkaline regulator is used to make the pH value of the premixed solution 7.2-11; (4) The premixed solution further comprises: a dispersant; (5) The first temperature is 40-75° C., and the mixture is stirred at the first temperature and at a speed of 200-600 rpm for a reaction time of 0.5-6 hours to generate an amino resin prepolymer; (6) In the premixed solution, the molar ratio of the first source to the second source is 1:(1-10), and the mass of the dispersant is 3-30% of the sum of the mass of the first source and the second source; (7) The amino resin prepolymer includes at least one of urea-formaldehyde prepolymer, urea-paraformaldehyde prepolymer, melamine-formaldehyde prepolymer, melamine-paraformaldehyde prepolymer, benzoguanamine-formaldehyde prepolymer, benzoguanamine-paraformaldehyde prepolymer, polyurethane prepolymer, or polyester prepolymer.

4. The method for preparing amino resin fluorescent microspheres according to claim 1, characterized in that: In the first mixed liquid, the concentration of the acidic catalyst is 0.01-0.3 wt %.

5. The method for preparing amino resin fluorescent microspheres according to claim 1, characterized in that: In step S2, the catalytic absorbent is used to promote the fluorescent material to enter the interior of the amino resin microspheres. Preferably, when the fluorescent material contains a basic group, an acid catalytic absorber is used; When the fluorescent material contains an acidic group, a base-catalyzed absorber is used; Preferably, the basic group includes at least one of a primary amine, a secondary amine, and a carbon-nitrogen double bond; and the acidic group includes at least one of a carboxyl group, a phenol, and a sulfonic acid.

6. The method for preparing amino resin fluorescent microspheres according to claim 1, characterized in that: In the second mixed solution, the concentration of the amino resin microspheres is 20-50 mg / ml, the mass of the fluorescent material is 0.01-1% of the mass of the amino resin microspheres, the mass proportion of the acid catalytic absorbent is 0.1-0.5wt%, and the concentration of the base catalytic absorbent is 2-8mmol / L.

7. The method for preparing amino resin fluorescent microspheres according to claim 1, characterized in that: The surface of the amino resin fluorescent microspheres obtained in step S2 is coated with a shell layer, and the shell layer includes an inorganic shell layer or an organic shell layer.

8. An amino resin fluorescent microsphere, characterized in that: The amino resin fluorescent microspheres are obtained by the preparation method of amino resin fluorescent microspheres according to any one of claims 1 to 7.

9. A method for preparing a tracer, characterized in that: The preparation method comprises step S1 and step S2 as described in any one of claims 1 to 7, and the step: S3, connecting the amino resin fluorescent microspheres to the functional groups.

10. A tracer, characterized in that: The tracer is obtained by the tracer preparation method according to claim 9.