Oily slow-release tracer agent and preparation method thereof

Abstract

The invention provides an oily sustained-release tracer and a preparation method thereof. The preparation method comprises the following steps: S1, preparing a premixture: uniformly mixing oily fluorescent microspheres, an oily sustained-release material, a diluent and skeleton resin to form the premixture; adding the supporting particles into the reaction equipment, maintaining stirring and keeping a first temperature; and S2, adding the pre-mixture into reaction equipment, uniformly mixing, then adding a curing agent for reaction, and forming a sustained-release layer coating the supporting particles by the oily fluorescent microspheres, the oily sustained-release material and a cured product of the diluent and the skeleton resin, so as to obtain the oily sustained-release tracer agent.

Description

Technical Field

[0001] This application belongs to the technical field of tracers. Specifically, it relates to an oil-based slow-release tracer and a preparation method thereof. Background Art

[0002] Fluorescent microspheres are formed by coating one or more fluorescent materials with a shell layer, which mainly serves to protect the fluorescent materials. The fluorescent materials mainly include: organic fluorescent dyes, quantum dots, metal oxides, etc. These fluorescent materials are vulnerable to environmental influences, such as being easily degraded, easily photo-bleached, not resistant to high temperature / strong light irradiation, not resistant to water and oxygen, etc. Therefore, in the prior art, most fluorescent materials are coated with inorganic shell layers or organic polymer shell layers. The fluorescent materials are excited by light or electricity to emit fluorescence. By virtue of different types of fluorescent components and different fluorescent contents, multiple different emission bands (colors) can be formed, which have the function of encoding. Therefore, they are widely used in fields such as biological labeling, disease diagnosis, tracers, solid-phase chips, liquid-phase chips, immunochromatography, Raman scattering, etc.

[0003] Fluorescent microspheres can be applied to petroleum tracers. By detecting data such as the types and quantities of fluorescent microspheres through sampling ports, parameters such as the production volume and flow rate of petroleum can be analyzed. Fluorescent microspheres usually cannot be directly applied to this environment. Usually, sand grains such as quartz sand and ceramsite sand are used as the core, and a slow-release layer containing fluorescent microspheres is coated on the surface of the sand grains to be used as a petroleum tracer. The fluorescent microspheres in the slow-release layer are slowly released into the petroleum, and then samples are taken for detection.

[0004] In the synthesis and preparation of petroleum tracers in the prior art, flammable components such as ethanol are used as solvents, which pose safety hazards, require high requirements for the production plant area, and have high input costs; and subsequent high-temperature evaporation of the solvent and high-temperature curing will generate some volatile substances such as formaldehyde, which is not environmentally friendly and harmful to physical health; the high temperature during the synthesis process and the cooling process result in a long synthesis time, usually 8 - 12 hours; the high temperature will also have an adverse effect on the fluorescent microspheres, making the fluorescent microspheres prone to decomposition and instability.

[0005] In view of this, this application provides an oil-based slow-release tracer and a preparation method thereof, which do not use solvents and adopt a dry process at normal temperature, with safe production, no volatile substances, and environmental protection; the synthesis steps are simple, and the synthesis time is greatly shortened; the synthesis at normal temperature makes the fluorescent microspheres not easily decomposed and stable. Summary of the Invention

[0006] The purpose of this application is to provide an oil-based slow-release tracer and a preparation method thereof, which do not use solvents and adopt a dry process at normal temperature, with safe production, no volatile substances, and environmental protection; the synthesis steps are simple, and the synthesis time is greatly shortened; the synthesis at normal temperature makes the fluorescent microspheres not easily decomposed and stable.

[0007] In the first aspect of the present application, a method for preparing an oil-based sustained-release tracer is provided, and the method includes:

[0008] S1, preparing a premix: mixing oil-based fluorescent microspheres, an oil-based sustained-release material, a diluent, and a skeletal resin uniformly to form a premix; adding support particles to a reaction device, maintaining stirring, and keeping a first temperature;

[0009] S2, adding the premix to the reaction device and mixing uniformly, then adding a curing agent for reaction (referred to as a reaction mixture), and a cured product of the oil-based fluorescent microspheres, the oil-based sustained-release material, the diluent, and the skeletal resin forms a sustained-release layer coating the support particles to obtain an oil-based sustained-release tracer.

[0010] In some embodiments, in step S1, the support particles include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0011] Furthermore, the stirring speed of the support particles in the reaction device is 100 - 1000 rpm, and the first temperature is 10 - 150 °C.

[0012] Furthermore, in the reaction mixture, the mass ratio of the support particles is 85 - 98 wt%.

[0013] In some embodiments, the skeletal resin includes at least one of phenolic resin, modified phenolic resin, and glycidyl ether epoxy resin.

[0014] The modified phenolic resin includes at least one of polyamide-modified phenolic resin, dicyandiamide-modified phenolic resin, epoxy-modified phenolic resin, or polyvinyl acetal-modified phenolic resin. The glycidyl ether epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether. Except for these listed skeletal resins, as long as the crosslinked cured product has high temperature resistance and is insoluble and infusible in petroleum, the skeletal resin components are within the protection scope of the present application.

[0015] Furthermore, in the premix, the mass ratio of the skeletal resin is 50 - 85 wt%. Preferably, in the premix, the mass ratio of the skeletal resin is 60 - 75 wt%.

[0016] In some embodiments, the diluent can dissolve the oily sustained-release material and the oily fluorescent microspheres, has epoxy groups, and has a viscosity ≤ 100 mPa·s (at 25 °C). Preferably, the diluent has a viscosity ≤ 50 mPa·s (at 25 °C).

[0017] Furthermore, the diluent includes at least one of: epoxyethyl methyl neodecanoate, C8-C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy)propyl ether. The viscosities of these diluents are ≤ 50 mPa·s (at 25 °C).

[0018] Furthermore, in the premix, the mass proportion of the diluent is 7-40 wt%. Preferably, in the premix, the mass proportion of the diluent is 15-25 wt%.

[0019] In some embodiments, the oily sustained-release material can slowly dissolve and release in an oily solvent (such as petroleum) and can adhere to the surface of the support particles.

[0020] Furthermore, the oily sustained-release material includes at least one of: petroleum resin, calcium stearate.

[0021] Furthermore, the petroleum resin includes at least one of: C5 petroleum resin and its derivatives, or C9 petroleum resin and its derivatives.

[0022] Furthermore, in the premix, the mass proportion of the oily sustained-release material is 2-20 wt%. Preferably, in the premix, the mass proportion of the oily sustained-release material is 4-11 wt%.

[0023] In some embodiments, the oily fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and an oily ligand modified on the surface of the shell layer.

[0024] Furthermore, 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.

[0025] Furthermore, the shell layer is formed by hydrolysis and condensation of inorganic substances, or the shell layer is formed by polycondensation of resin precursors, or the shell layer is formed by self-assembly of amphiphilic polymer-coated microdroplets, or the shell layer is formed by polymerization of olefin monomers having carbon-carbon double bonds under the action of an initiator.

[0026] Further, the shell layer is hydrophilic or lipophilic, and ligand modification is performed on the fluorescent microspheres to convert them from hydrophilic to lipophilic, or to enhance the lipophilicity of the inherently lipophilic fluorescent microspheres, thereby forming oily fluorescent microspheres.

[0027] Further, in the pre-mixture, the mass proportion of the oily fluorescent microspheres is 1-8 wt%. Preferably, in the pre-mixture, the mass proportion of the oily fluorescent microspheres is 1.5-4 wt%.

[0028] In some embodiments, to prepare the pre-mixture, the oily fluorescent microspheres, the oily sustained-release material, and the diluent are first mixed evenly, and then the skeleton resin is added and mixed evenly.

[0029] In some embodiments, in step S2, all of the pre-mixture and the curing agent are added to the reaction equipment at one time, thereby forming a single sustained-release layer; or the pre-mixture and the curing agent are added to the reaction equipment in multiple times (two or more times), thereby forming multiple sustained-release layers.

[0030] Further, if the pre-mixture and the curing agent are added to the reaction equipment in multiple times, the amounts of the pre-mixture and the curing agent added each time and the mass proportions of the respective components may be the same or different.

[0031] In some embodiments, the curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products (such as EH451K, EH485, EH3895L, 593 curing agent), alicyclic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

[0032] Further, in step S2, the mass ratio of the added pre-mixture to the curing agent is (2-10):1. Preferably, in step S2, the mass ratio of the added pre-mixture to the curing agent is (4-6):1.

[0033] In the second aspect of the present application, an oily sustained-release tracer is provided. The oily sustained-release tracer includes: support particles and a sustained-release layer coating the support particles. The sustained-release layer includes: a cross-linked reaction cured product formed by the diluent and the skeleton resin coating on the surface of the support particles, and oily fluorescent microspheres and an oily sustained-release material distributed between the cured products.

[0034] In some embodiments, the support particles include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0035] In some embodiments, the skeletal resin includes at least one of phenolic resin, modified phenolic resin, and glycidyl ether epoxy resin.

[0036] The modified phenolic resin includes at least one of polyamide modified phenolic resin, dicyandiamide modified phenolic resin, epoxy modified phenolic resin, or polyvinyl acetal modified phenolic resin. The glycidyl ether epoxy resin includes at least one of bisphenol A epoxy resin (bisphenol A monoglycidyl ether), bisphenol F epoxy resin (bisphenol F diglycidyl ether), tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether.

[0037] In some embodiments, the diluent can dissolve the oil-based sustained-release material and the oil-based fluorescent microspheres, has epoxy groups, and its viscosity ≤ 100 mPa·s (at 25°C). Preferably, the viscosity of the diluent ≤ 50 mPa·s (at 25°C).

[0038] Furthermore, the diluent includes at least one of neodecanoic acid epoxyethyl methyl ester, C8-C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy)propyl ether.

[0039] In some embodiments, the oil-based sustained-release material can slowly dissolve and release in an oil-based solvent (such as petroleum) and can adhere to the surface of the support particles.

[0040] Furthermore, the oil-based sustained-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, or C9 petroleum resin and its derivatives.

[0041] In some embodiments, the oil-based fluorescent microspheres include a fluorescent material, a shell layer coating the fluorescent material, and an oil-based ligand modified on the surface of the shell layer.

[0042] The oil-based sustained-release tracer and its preparation method of the present application have at least the following advantages compared with the prior art:

[0043] (1) Instead of using a solvent (dry process), this application uses a diluent to replace the conventional solvent. This diluent can dissolve the oil-based fluorescent microspheres and the oil-based sustained-release material, and its viscosity ≤ 100 mPa·s (at 25 °C). It has strong fluidity like a fluid at room temperature, achieving the function of replacing the solvent. And this diluent has epoxy groups, which can crosslink and cure with the skeleton resin under the action of a curing agent, coating and firmly bonding to the surface of the support particles. Therefore, there is no need for the step of high-temperature evaporation to remove the solvent, ensuring production safety, no volatile substances, and environmental protection. The synthesis steps are simple, without high-temperature and cooling steps, greatly shortening the synthesis time. It can be synthesized at room temperature, making the oil-based fluorescent microspheres not easily decomposed and stable.

[0044] (2) Since this application uses a diluent to replace the solvent, the oil-based sustained-release material and the oil-based fluorescent microspheres are dissolved in the diluent, that is, uniformly dispersed in the diluent. When the diluent crosslinks and cures with the skeleton resin, the oil-based sustained-release material and the oil-based fluorescent microspheres are uniformly dispersed in the cured product, that is, uniformly dispersed in the sustained-release layer, also avoiding the phenomenon that some oil-based fluorescent microspheres are coated by the oil-based sustained-release material but not cured on the surface of the support particles.

[0045] (3) Adding the premix and the curing agent in multiple times to form multiple layers of diluent layers can increase the thickness and uniformity of the sustained-release layer, and the oil-based sustained-release material and the oil-based fluorescent microspheres are protected by the cured products layer by layer, which can enhance the sustained-release effect.

[0046] (4) Based on the dry process, this application can achieve low-temperature, medium-temperature, and high-temperature curing according to the choice of the curing agent, with wide application. Brief Description of the Drawings

[0047] Combined with the following attached Figure 1 When reading together, the above and other features of the content of this application will be more fully described. It can be understood that these drawings only depict several embodiments of the content of this application, so it should not be considered as a limitation on the scope of the content of this application. By using the drawings, the content of this application will be more clearly and detailedly described.

[0048] Figure 1 It is a microscope image of the oil-based sustained-release tracer in Example 1 of this application.

[0049] Figure 2 It is a microscope image of the oil-based sustained-release tracer in Example 2 of this application.

[0050] Figure 3 It is a microscope image of the oil-based sustained-release tracer in Example 3 of this application.

[0051] Figure 4 It is a microscope image of the oil-based sustained-release tracer in Example 4 of this application.

[0052] Figure 5 Microscopic image of the oil-based slow-release tracer of Example 5 of this application.

[0053] Figure 6 Microscopic image of the oil-based slow-release tracer of Example 6 of this application.

[0054] Figure 7 Microscopic image of the oil-based slow-release tracer of Comparative Example 1 of this application.

[0055] Figure 8 Microscopic image of the oil-based slow-release tracer of Comparative Example 2 of this application. Detailed implementation manners

[0056] The following examples are described to assist in understanding this application. The examples are not and should not in any way be construed as limiting the scope of protection of this application.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) in this specification can be defined as commonly understood by those skilled in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in a common dictionary, should be interpreted as having a meaning consistent with their meaning in the context of this disclosure and the relevant art, and will not be interpreted in an idealized or overly formal sense unless clearly so defined herein.

[0058] As used herein, the term "at least one", when preceding or following a list of elements, modifies the entire list of elements rather than individual elements of the list and will not be construed as limiting "one". "Or" means "and / or". The terms "comprising" and "including", when used in this specification, indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or their combinations. Thus, the above language will be understood to mean including the stated elements but not precluding any other elements. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "plurality" means two or more. The term "connected" means directly connected or indirectly connected. It will be understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, it can be directly on the other element or there can also be intervening elements. In contrast, when an element is referred to as "directly on" another element, there are no intervening elements. To clearly illustrate the embodiments in the figures, some parts that are not actually relevant to the description may be omitted. The terms "first", "second", "third", etc. may be used herein to describe and distinguish various different elements, components, regions, layers, and / or parts, but these elements, components, regions, layers, and / or parts should not be limited by these terms.

[0059] In a first aspect of the present application, a method for preparing an oil-based sustained-release tracer is provided, the method comprising:

[0060] S1, preparing a premix: mixing oil-based fluorescent microspheres, an oil-based sustained-release material, a diluent, and a skeletal resin uniformly to form a premix; adding support particles to a reaction device, maintaining stirring, and keeping a first temperature;

[0061] S2, adding the premix to the reaction device and mixing uniformly, then adding a curing agent for reaction (referred to as a reaction mixture), and a cured product of the oil-based fluorescent microspheres, the oil-based sustained-release material, the diluent, and the skeletal resin forms a sustained-release layer coating the support particles to obtain an oil-based sustained-release tracer.

[0062] In some embodiments, in step S1, the support particles include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0063] Furthermore, the stirring speed of the support particles in the reaction device is 100 - 1000 rpm, and the first temperature is 10 - 150 °C.

[0064] Preferably, the stirring speed of the support particles in the reaction equipment is 200 - 700 rpm, and the first temperature is 10 - 80 °C. More preferably, the first temperature is 10 - 40 °C.

[0065] Furthermore, in the reaction mixture, the mass ratio of the support particles is 85 - 98 wt%. Preferably, in the reaction mixture, the mass ratio of the support particles is 90 - 98 wt%.

[0066] In some embodiments, the skeletal resin includes at least one of phenolic resin, modified phenolic resin, and glycidyl ether type epoxy resin.

[0067] The modified phenolic resin includes at least one of polyamide modified phenolic resin, dicyandiamide modified phenolic resin, epoxy modified phenolic resin, or polyvinyl acetal modified phenolic resin. The glycidyl ether type epoxy resin includes at least one of bisphenol A epoxy resin (bisphenol A monoglycidyl ether), bisphenol F epoxy resin (bisphenol F diglycidyl ether), tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether. Except for these listed skeletal resins, as long as the crosslinked cured product is heat-resistant and does not dissolve in or melt in petroleum, the skeletal resin components are within the protection scope of this application.

[0068] Furthermore, in the premix, the mass ratio of the skeletal resin is 50 - 85 wt%. Preferably, in the premix, the mass ratio of the skeletal resin is 60 - 75 wt%.

[0069] The skeletal resin undergoes a crosslinking reaction under the action of a curing agent and cures to form a network structure polymer (cured product), which coats and firmly adheres to the surface of the support particles. The cured product of the skeletal resin is heat-resistant and does not dissolve in or melt in oily solvents such as petroleum and gasoline, and has strong adhesion to the support particles and high consolidation strength, playing a role in protecting the oily sustained-release material and the oily fluorescent microspheres, preventing the oily sustained-release material and the oily fluorescent microspheres from being quickly dissolved and failing to achieve the sustained-release effect.

[0070] In some embodiments, the diluent can dissolve the oily sustained-release material and the oily fluorescent microspheres, has an epoxy group, and its viscosity ≤ 100 mPa·s (at 25 °C). Preferably, the viscosity of the diluent ≤ 50 mPa·s (at 25 °C).

[0071] Furthermore, the diluent includes at least one of epoxyethyl methyl neodecanoate, C8-C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy) propyl ether. The viscosity of these diluents is ≤50 mPa·s (at 25°C). Except for these listed diluent components, as long as they meet the three conditions of being able to dissolve the oily sustained-release material and the oily fluorescent microspheres, having epoxy groups, and having a viscosity ≤70 mPa·s, they are within the protection scope of this application.

[0072] Furthermore, in the pre-mixture, the mass ratio of the diluent is 7-40 wt%. Preferably, in the pre-mixture, the mass ratio of the diluent is 15-25 wt%.

[0073] In the prior art, ethanol, ethyl acetate, etc. are usually used as solvents to dissolve fluorescent microspheres and sustained-release materials. After forming a sustained-release tracer, these solvents are evaporated at high temperature, which is called the wet process. Producing with flammable components such as ethanol has safety hazards, requires high requirements for the production plant area, and has a large input cost; and high temperature will generate some volatile substances such as formaldehyde (such as the MF shell layer will release formaldehyde at high temperature), which is not environmentally friendly and harmful to physical health; using high-temperature synthesis is likely to cause the decomposition and instability of fluorescent microspheres; and the synthesis time of the wet process is long, usually 8-12 hours.

[0074] However, this application does not use solvents and can be called the dry process. This application uses a diluent to replace the conventional solvent. This diluent can dissolve oily fluorescent microspheres and oily sustained-release materials, and its viscosity is ≤100 mPa·s (at 25°C). It has strong fluidity like a fluid at room temperature and achieves the function of replacing the solvent; and this diluent has epoxy groups and can undergo a cross-linking reaction with the skeleton resin under the action of a curing agent and cure, coating and firmly bonding to the surface of the support particles. Therefore, there is no need to perform the step of evaporating the solvent at high temperature, there are no volatile substances, and the synthesis step is simple; the room-temperature synthesis also makes the oily fluorescent microspheres not easily decomposed and stable. This application does not need to use solvents such as ethanol, so it is safe in production; there are also no volatile substances, which is environmentally friendly and healthy; the synthesis step is simpler, without high-temperature evaporation and cooling, and the synthesis time is greatly shortened (2-5 hours); the room-temperature synthesis makes the fluorescent microspheres not easily decomposed and stable.

[0075] The diluent and the backbone resin described in this application undergo a crosslinking reaction under the action of a curing agent and cure to form a cured product that coats and firmly adheres to the surface of the support particles. It is resistant to high temperatures, insoluble in, and does not melt in petroleum and gasoline, and together they play a role in protecting the oil-based sustained-release material and the oil-based fluorescent microspheres. Since the diluent uniformly dissolves the oil-based sustained-release material and the oil-based fluorescent microspheres, and although the liquid backbone resin is liquid but insoluble in the diluent (mixed evenly but phase-separated), in the sustained-release layer, the oil-based fluorescent microspheres are wrapped by the oil-based sustained-release material and are released as the oil-based sustained-release material slowly releases in petroleum, etc. The oil-based sustained-release material itself also has a certain adhesiveness. The oil-based sustained-release material and the oil-based fluorescent microspheres are dispersed between the network structure polymers formed by the cured product and in the mesh pores, and the cured product plays a role in supporting and protecting the oil-based sustained-release material and the oil-based fluorescent microspheres. Since this application uses a diluent to replace the solvent, the oil-based sustained-release material and the oil-based fluorescent microspheres are dissolved in the diluent, that is, uniformly dispersed in the diluent. When the diluent and the backbone resin undergo a crosslinking reaction and cure together, it makes the oil-based sustained-release material and the oil-based fluorescent microspheres uniformly dispersed in the cured product, that is, uniformly dispersed in the sustained-release layer, and also avoids the phenomenon that some oil-based fluorescent microspheres are wrapped by the oil-based sustained-release material but not cured on the surface of the support particles.

[0076] In some embodiments, the oil-based sustained-release material can slowly dissolve and release in an oil-based solvent (such as petroleum) and can adhere to the surface of the support particles.

[0077] Further, the oil-based sustained-release material includes at least one of petroleum resin and calcium stearate.

[0078] Further, the petroleum resin includes at least one of C5 petroleum resin and its derivatives, or C9 petroleum resin and its derivatives.

[0079] Further, in the premix, the mass ratio of the oil-based sustained-release material is 2-20 wt%. Preferably, in the premix, the mass ratio of the oil-based sustained-release material is 4-11 wt%.

[0080] In some embodiments, the oil-based fluorescent microspheres include a fluorescent material, a shell layer coating the fluorescent material, and an oil-based ligand modified on the surface of the shell layer.

[0081] Further, 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.

[0082] The quantum dots include at least one of IIB-VIA group quantum dots, IIIA-VA group quantum dots, IVA-VIA group quantum dots, IVA group quantum dots, IB-IIIA-VIA group quantum dots, IB-IIB-IVA-VIA group quantum dots, VIII-VIA group quantum dots, perovskite quantum dots, and carbon quantum dots (carbon dots). For example, the IIB-VIA group quantum dots include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or a combination thereof. For example, the IIIA-VA group 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 a combination thereof. For example, the 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, the IVA group quantum dots include: Si, Ge, SiC, SiGe, or a combination thereof. For example, the IB-IIIA-VIA group quantum dots include: CuInSe2, CuInS2, CuInGaSe, CuInGaS, or a combination thereof. For example, the 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, where A is a monovalent amine organic cation, a monovalent inorganic metal cation (such as CH3NH3. + , NH2CHNH2+, C(NH2)3 + , Cs + , Li + , Na + , K + , Rb + , an aryl group, 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 under high-temperature conditions such as in a microwave oven or heating, carbon quantum dots with a particle size of about 10 nm are synthesized by carbonization. Most carbon quantum dots are mainly composed of amorphous carbon to crystalline carbon nuclei and are carbon mainly hybridized with sp 2 . These components are usually the nuclear components of the quantum dots. Quantum dots usually also include one or more shells that wrap the nuclear body (the outer shell is usually ZnS). In addition to these listed quantum dots, other common quantum dots are also applicable to this application and are within the protection scope of this application. The metal oxides of metal oxide nanoparticles include: Zn, Cr, Co, Dy, Er, Eu, Fe, Gd, Gd, Pr, Nd, Ni, In, Pr, Sm, Tb, Tm, and combinations thereof.

[0083] The structure of the fluorescent polymer has a functional group that can emit fluorescence (such as fluorescein, etc.) and monomers that can undergo polymerization reactions. The monomers polymerize with each other or with other monomers that do not contain fluorescence, thereby preparing a fluorescent polymer. Organic fluorescent dyes include: fluorescein (stilbenes, coumarins, fluorans, benzoxazoles, naphthalenedicarboximides, thiophene dicarboxylic acid amides, polycyclic aromatic hydrocarbons, perylene tetracarboxylic diimides, etc.), aromatic polycyclic compounds, intramolecular charge transfer compounds, metal complex fluorescent materials, enzymes, rare earth metal chelates.

[0084] Furthermore, the shell is formed by hydrolysis and condensation of inorganic substances, or the shell is formed by polycondensation of resin precursors, or the shell is formed by self-assembly of amphiphilic polymer-coated microdroplets, or the shell is formed by polymerization of olefin monomers with carbon-carbon double bonds under the action of an initiator.

[0085] The shell layer is formed by hydrolysis and condensation of inorganic substances. The formed inorganic shell layer includes one of a silica shell layer, a titanium dioxide shell layer, or a zirconium dioxide shell layer. The shell layer is formed by polycondensation of a resin precursor. The formed organic shell layer includes one of a urea-formaldehyde shell layer, a urea-polyformaldehyde shell layer, a melamine-formaldehyde shell layer, a melamine-polyformaldehyde shell layer, a urea-melamine-polyformaldehyde shell layer, or a benzoguanamine-formaldehyde shell layer. The shell layer is formed by self-assembly of amphiphilic polymer-coated microdroplets. The amphiphilic polymer coats the water-in-oil / oil-in-water microdroplets, and then the internal phase solvent of the microdroplets is evaporated for self-assembly, so that the amphiphilic polymer physically coats the fluorescent material. The amphiphilic polymer includes one of poly(octadecyl maleate) (PMAO), poly(hexadecyl maleate), or poly(tetradecyl maleate). These microspheres have carboxyl groups on their surfaces. The shell layer is formed by polymerization of an olefin monomer having a carbon-carbon double bond under an initiating action. The olefin monomer having a carbon-carbon double bond undergoes a polymerization reaction under the initiating action of an initiator, light, etc. to form an organic polymer shell layer.The vinyl monomers include at least one of vinyl chloride, allyl ether, diethyl diallylmalonate, diallyl disulfide, methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, N-vinylpyrrolidone, acrylonitrile, vinyl acetate, maleic anhydride, methylene succinic acid, styrenesulfonic acid, sodium vinyl sulfonate, styrene, α-methylstyrene, vinylstyrene, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, dicyclopentanyl (meth)acrylate (HDCPMA), cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate (AMA), 2-adamantyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate (LMA), stearyl (meth)acrylate, ethylene oxide, propylene oxide, butylene oxide, epoxybenzene, methyloxirane, ethylene glycol diglycidyl ether, stilbene tetroxide, divinylbenzene, divinyltoluene, trivinylbenzene, diethyl diallylmalonate, diallyl disulfide, 1,3-butadiene, isoprene, isobutylene, dipropylene glycol di(meth)acrylate, tetraethylene glycol dimethacrylate, dimethacrylic acid, dodecanediol ester, decanediol ester, tricyclodecane dimethanol acrylate, hexanediol diacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, trimethylolpropane trimethacrylate.

[0086] Furthermore, the shell is hydrophilic or lipophilic. By performing ligand modification on the fluorescent microspheres, the hydrophilic property is transformed into lipophilic property, or the lipophilic property of the inherently lipophilic fluorescent microspheres is enhanced to form oil-based fluorescent microspheres.

[0087] The oily ligands include at least one of: polydimethylsiloxane, triethylchlorosilane, epoxyhexadecane, epoxy tetradecane, hexadecylamine, octadecylamine, chlorinated polystyrene, octadecyl maleic anhydride ester, hexadecyl maleic anhydride ester, tetradecyl maleic anhydride ester, polyethylene-alt-maleic anhydride copolymer, polypropylene-alt-maleic anhydride copolymer, polystyrene-alt-maleic anhydride copolymer, poly(maleic anhydride-1-octadecene), poly(maleic anhydride-1-hexadecene), poly(maleic anhydride-1-tetradecene), polyvinylpyrrolidone-hexadecene copolymer, polyoxyethylene-polyoxypropylene copolymer, long-chain fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, sorbitan trioleate, sorbitan monostearate, sorbitan monooleate, sorbitan laurate.

[0088] Furthermore, the oily fluorescent microspheres further include magnetic materials, and the shell layer coats the fluorescent materials and magnetic materials. The magnetic substances include one or more of: magnetite, iron oxide, nickel oxide, cobalt oxide, magnetite, iron oleate, ferric chloride, ferric sulfate, ferric nitrate, ferrous chloride tetrahydrate, ferric chloride hexahydrate, nickel ferrite, aluminum ferrite, manganese ferrite, zinc ferrite, cobalt ferrite, CoFe2O4, NiFe2O4, or MnFe2O4.

[0089] Furthermore, in the pre-mixture, the mass ratio of the oily fluorescent microspheres is 1-8 wt%. Preferably, in the pre-mixture, the mass ratio of the oily fluorescent microspheres is 1.5-4 wt%.

[0090] In some embodiments, to prepare the pre-mixture, first mix the oily fluorescent microspheres, the oily sustained-release material and the diluent evenly, and then add the skeleton resin and mix evenly.

[0091] Both the oily fluorescent microspheres and the oily sustained-release material are granular, and the diluent can dissolve the oily fluorescent microspheres and the oily sustained-release material. First dissolve the two separately and then mix them to facilitate uniform stirring, and finally add the liquid skeleton resin.

[0092] In some embodiments, in step S2, all of the pre-mixture and the curing agent are added to the reaction device at one time, i.e., a single sustained-release layer is formed; or the pre-mixture and the curing agent are added to the reaction device in multiple times (two or more times), i.e., multiple sustained-release layers are formed.

[0093] Furthermore, if the pre-mixture and the curing agent are added to the reaction device in multiple times, the amounts of the pre-mixture and the curing agent added each time and the mass ratios of the components are the same or different.

[0094] In some embodiments, the curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products (such as EH451K, EH485, EH3895L, 593 curing agent), alicyclic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

[0095] In the art, there are two aspects that affect the synthesis temperature. On the one hand, it is the solvent, including the temperature required for the solvent to dissolve other components and the temperature required to evaporate the solvent. On the other hand, it is the curing agent, which is divided into low-temperature (below 50°C), medium-temperature (50 - 100°C), and high-temperature (>100°C) curing agents, and can be selected according to requirements. Since this application uses a diluent to replace the solvent, it can dissolve other components at room temperature and does not require evaporation removal, solving the main problem of high-temperature synthesis in the prior art. Therefore, the curing agent can be selected adaptively. That is to say, based on the dry process, low-temperature, medium-temperature, and high-temperature curing can be achieved according to the selection of the curing agent, with wide application. In this application, of course, medium-low temperature curing agents are preferred, and low-temperature curing agents are more preferred, so that room-temperature synthesis can be achieved. The above-listed curing agents are common low-temperature curing agents, and other medium-low temperature curing agents are also applicable to this application.

[0096] Further, in step S2, the mass ratio of the added premix to the curing agent is (2 - 10):1. Preferably, in step S2, the mass ratio of the added premix to the curing agent is (4 - 6):1.

[0097] In the second aspect of this application, an oil-based slow-release tracer is provided. The oil-based slow-release tracer includes: support particles and a slow-release layer coating the support particles. The slow-release layer includes: a cross-linked reaction cured product of a diluent and a backbone resin coated on the surface of the support particles, and oil-based fluorescent microspheres and oil-based slow-release materials distributed between the cured products.

[0098] In some embodiments, the support particles include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0099] In some embodiments, the backbone resin includes at least one of phenolic resin, modified phenolic resin, and glycidyl ether type epoxy resin.

[0100] The modified phenolic resin includes at least one of polyamide-modified phenolic resin, dicyandiamide-modified phenolic resin, epoxy-modified phenolic resin, or polyvinyl acetal-modified phenolic resin. The glycidyl ether type epoxy resin includes at least one of bisphenol A epoxy resin (bisphenol A monoglycidyl ether), bisphenol F epoxy resin (bisphenol F diglycidyl ether), tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether.

[0101] In some embodiments, the diluent can dissolve the oil-based sustained-release material and the oil-based fluorescent microspheres, has epoxy groups, and its viscosity ≤ 100 mPa·s (at 25 °C). Preferably, the viscosity of the diluent ≤ 50 mPa·s (at 25 °C).

[0102] Furthermore, the diluent includes at least one of neodecanoic acid epoxyethyl methyl ester, C8-C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy)propyl ether.

[0103] In some embodiments, the oil-based sustained-release material can slowly dissolve and release in an oil-based solvent (such as petroleum) and can adhere to the surface of the support particles.

[0104] Furthermore, the oil-based sustained-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, or C9 petroleum resin and its derivatives.

[0105] In some embodiments, the oil-based fluorescent microspheres include a fluorescent material, a shell layer coating the fluorescent material, and an oil-based ligand modified on the surface of the shell layer.

[0106] Hereinafter, the present invention will be further described in detail with specific examples and comparative examples, but the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the conditions not specified are conventional conditions in the industry.

[0107] Example 1:

[0108] Preparation of premix: Take 50 g of oil-based fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is urea-polyformaldehyde, and the oil-based ligand is polymaleic anhydride-1-octadecene and polyoxyethylene-polyoxypropylene copolymer), add 375 g of butyl glycidyl ether, and ultrasonically mix at room temperature of 25 °C and a power of 400 W for 5 min; then add 180 g of C5 petroleum resin and stir at a rotation speed of 500 rmp at room temperature of 25 °C for 15 min; then add 1200 g of bisphenol A epoxy resin and continue to stir for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0109] Add 50 kg of quartz sand to a 50 L reaction kettle, and stir at a rotation speed of 400 rmp at room temperature of 25 °C; add the above-mentioned premix to the reaction kettle and stir and disperse for 15 min; then add 500 g of modified aliphatic amine (curing agent 593), react and cure for 1 h; discharge to obtain an oil-based slow-release tracer.

[0110] Example 2:

[0111] Preparation of premix: Take 50 g of oil-based fluorescent microspheres (the fluorescent material is ZnSeTe blue quantum dots, the shell layer is silica, and the oil-based ligand is polymaleic anhydride octadecene and hydroxyl-terminated polydimethylsiloxane), add 380 g of epoxyethylmethyl neodecanoate, and ultrasonically mix at room temperature of 25 °C and a power of 400 W for 8 min; then add 200 g of C9 petroleum resin and stir at a rotation speed of 500 rmp at room temperature of 25 °C for 15 min; then add 1250 g of phenolic resin and continue to stir for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0112] Add 50 kg of quartz sand to a 50 L reaction kettle, and stir at a rotation speed of 400 rmp at room temperature of 25 °C; add the above-mentioned premix to the reaction kettle and stir and disperse for 15 min; then add 480 g of modified aliphatic amine curing agent (curing agent EH-451K), react and cure for 1 h; discharge to obtain an oil-based slow-release tracer.

[0113] Example 3:

[0114] Preparation of premix: Take 50 g of oil-based fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is polyacrylic acid, and the oil-based ligand is methyl methacrylate-styrene copolymer and triethylchlorosilane), add 370 g of nonylphenol glycidyl ether, and ultrasonically mix at room temperature of 25 °C and a power of 400 W for 5 min; then add 190 g of C5 petroleum resin and stir at a rotation speed of 500 rmp at room temperature of 25 °C for 15 min; then add 1280 g of epoxy-modified phenolic resin and continue to stir for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0115] Add 50 kg of quartz sand to a 50 L reactor, stir at a speed of 400 rmp at room temperature of 25°C; add the said premix to the reactor and stir and disperse for 15 min; then add 520 g of modified aliphatic amine curing agent (curing agent EH-485), react and cure for 1 h; discharge to obtain an oil-based slow-release tracer.

[0116] Example 4:

[0117] Prepare a premix: Take 50 g of oil-based fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is urea-polyformaldehyde, and the oil-based ligand is poly(maleic anhydride-1-octadecene) and poly(ethylene oxide)-poly(propylene oxide) copolymer), add 375 g of butyl glycidyl ether, ultrasonically mix at a power of 400 W at room temperature of 25°C for 5 min; then add 180 g of C5 petroleum resin, stir at a speed of 500 rmp at room temperature of 25°C for 15 min; then add 1200 g of bisphenol A epoxy resin and continue to stir for 20 min (stirring speed of 500 rmp at room temperature of 25°C).

[0118] Add 50 kg of ceramsite sand to a 50 L reactor, stir at a speed of 400 rmp at room temperature of 25°C; add the said premix to the reactor and stir and disperse for 15 min; then add 500 g of modified aliphatic amine (curing agent 593), react and cure for 1 h; discharge to obtain an oil-based slow-release tracer.

[0119] Example 5:

[0120] Prepare a premix: Take 50 g of oil-based fluorescent microspheres (the fluorescent material is ZnSeTe blue quantum dots, the shell layer is silica, and the oil-based ligand is poly(maleic anhydride octadecene) and hydroxyl-terminated polydimethylsiloxane), add 380 g of epoxyethyl methyl neodecanoate, ultrasonically mix at a power of 400 W at room temperature of 25°C for 8 min; then add 200 g of C9 petroleum resin, stir at a speed of 500 rmp at room temperature of 25°C for 15 min; then add 1250 g of phenolic resin and continue to stir for 20 min (stirring speed of 500 rmp at room temperature of 25°C).

[0121] Add 50 kg of ceramsite sand to a 50 L reactor, stir at a speed of 400 rmp at room temperature of 25°C; add the said premix to the reactor and stir and disperse for 15 min; then add 480 g of modified aliphatic amine curing agent (curing agent EH-451K), react and cure for 1 h; discharge to obtain an oil-based slow-release tracer.

[0122] Example 6:

[0123] Preparation of premix: Take 50 g of oily fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is polyacrylic acid, and the oily ligand is a copolymer of methacrylic acid - styrene and triethylchlorosilane), add 370 g of nonylphenol glycidyl ether, and ultrasonically mix at room temperature of 25 °C and a power of 400 W for 5 min; then add 190 g of C5 petroleum resin and stir at room temperature of 25 °C and a rotation speed of 500 rmp for 15 min; then add 1280 g of epoxy - modified phenolic resin and continue stirring for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0124] Add 50 kg of ceramsite sand to a 50 - L reaction kettle, and stir at a rotation speed of 400 rmp at room temperature of 25 °C; add the above - mentioned premix to the reaction kettle and stir and disperse for 15 min; then add 520 g of modified aliphatic amine curing agent (curing agent EH - 485), react and cure for 1 h; discharge the material to obtain an oily slow - release tracer.

[0125] Comparative Example 1:

[0126] Preparation of premix: Take 50 g of oily fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is urea - paraformaldehyde, and the oily ligand is a copolymer of poly maleic anhydride - 1 - octadecene and polyoxyethylene - polyoxypropylene copolymer), add 180 g of C5 petroleum resin and 600 g of ethyl acetate and mix evenly (ultrasonically mix at room temperature of 25 °C and a power of 400 W for 20 min); then add 1200 g of bisphenol A epoxy resin and continue stirring for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0127] Mix 50 kg of quartz sand and 27 kg of ethanol evenly in a reaction kettle (stir at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, put the second mixture into the reaction kettle and mix evenly (stir at 30 HZ for 20 min), and then raise the temperature to 80 °C to remove the solvent; after all the solvent is removed, add 500 g of modified aliphatic amine (curing agent 593) and react for 3 h. After cooling, discharge the material to obtain an oily slow - release tracer.

[0128] Comparative Example 2:

[0129] Preparation of premix: Take 50 g of oily fluorescent microspheres (the fluorescent material is sodium fluorescein, the shell layer is urea - paraformaldehyde, and the oily ligand is a copolymer of poly maleic anhydride - 1 - octadecene and polyoxyethylene - polyoxypropylene copolymer), add 180 g of C5 petroleum resin and 600 g of ethyl acetate and mix evenly (ultrasonically mix at room temperature of 25 °C and a power of 400 W for 20 min); then add 1200 g of bisphenol A epoxy resin and continue stirring for 20 min (stirring speed of 500 rmp at room temperature of 25 °C).

[0130] Mix 50 kg of ceramsite sand with 27 kg of ethanol evenly in a reaction kettle (stir at 30 HZ for 20 min), and heat up the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, put the second mixture into the reaction kettle and mix evenly (stir at 30 HZ for 20 min), then heat up to 80 °C to remove the solvent. After all the solvent is removed, add 500 g of modified aliphatic amine (curing agent 593) and react for 3 h. After cooling, discharge the material to obtain an oil-based slow-release tracer.

[0131] In Comparative Examples 1-2, ethanol and ethyl acetate were used as solvents. Ethanol was used to prevent quartz sand and ceramsite sand from caking, and ethyl acetate was used to dissolve oil-based fluorescent microspheres and oil-based slow-release materials. Subsequently, the solvent was evaporated by heating. Among them, ethanol, as a flammable component, is not safe in production, has high regulatory requirements for the production plant area, and high production costs; while the technical solution of the present application does not require the use of solvents. During the high-temperature synthesis process, the shell layer of urea-polyformaldehyde will also release formaldehyde volatiles, which is not environmentally friendly and harmful to the health of researchers / workers; while the technical solution of the present application can adopt room-temperature synthesis. Synthesizing under high-temperature conditions requires heating-up time and longer cooling time. Compared with the technical solution of the present application, the synthesis time will be much longer.

[0132] Take pictures of the oil-based slow-release tracers obtained in Examples 1-6 and Comparative Examples 1-2 respectively using a fluorescence microscope, and sequentially obtain the microscope Figures 1 - 8 . From Figures 1 - 6 It can be seen that the surface of the oil-based slow-release tracers in Examples 1-6 emits light evenly, indicating that the oil-based fluorescent microspheres on the surface of the support particles are distributed evenly, that is, the components of the slow-release layer are distributed evenly. From Figures 7 - 8 It can be seen that for the oil-based slow-release tracers in Comparative Examples 1-2, there is a phenomenon that although some oil-based fluorescent microspheres are coated, they are not fixed on the surface of the support particles.

[0133] Respectively take 10 g of the oil-based slow-release tracers obtained in Examples 1-6 and Comparative Examples 1-2, add 10 g of n-octane and mix evenly, then put them into an environment with a humidity of 85 RH and a temperature of 85 °C and start timing. After a certain period of time, take samples to detect their slow-release effects. For each sample, mix and suck 10 μl of liquid at the 30th h, 60th h, and 90th h respectively, and then count the number of oil-based fluorescent microspheres under a fluorescence microscope twice, take the average value, and the counting results are shown in Table 1.

[0134] Table 1: Slow-release data of the oil-based slow-release tracers in Examples 1-6 and Comparative Examples 1-2.

[0135]

[0136] As can be seen from Table 1, the sustained-release effects of Examples 1-6 are gentle and good. In the first 30 h, since the fluorescent microspheres on the surface of the tracer are relatively easy to be released, the number of released fluorescent microspheres is relatively large. However, the sustained-release rate tends to be stable in the subsequent time. Between the 30th h and the 60th h, and between the 60th h and the 90th h, by calculating the difference, it can be seen that the sustained-release rates are basically the same. For Comparative Examples 1-2, a large number of fluorescent microspheres are released in the first 30 h, and the release rate of the subsequent fluorescent microspheres is getting lower and lower, indicating that the tracer is not stable enough.

[0137] Although the present application has disclosed multiple aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art. Without departing from the concept of the present application, several modifications and improvements can be made, which all fall within the protection scope of the present application. The multiple aspects and embodiments disclosed in the present application are only for illustrative purposes and are not intended to limit the present application. The actual protection scope of the present application is subject to the claims.

Claims

1. A preparation method of an oil-based sustained-release tracer, characterized in that, The method includes: S1, preparing a premix: uniformly mixing an oily fluorescent microsphere, an oily sustained-release material, a diluent, and a skeletal resin to form a premix; adding support particles into a reaction device, maintaining stirring, and keeping a first temperature; S2, adding the premix into the reaction device and mixing uniformly, then adding a curing agent for reaction, and a cured product of the oily fluorescent microsphere, the oily sustained-release material, the diluent, and the skeletal resin forms a sustained-release layer coating the support particles to obtain an oily sustained-release tracer.

2. The preparation method of the oily sustained-release tracer according to claim 1, characterized in that, It includes one or more features selected from the following groups: (1) The support particles include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles; (2) The stirring speed of the support particles in the reaction device is 100 - 1000 rpm, and the first temperature is 10 - 150 °C; (3) The skeletal resin includes at least one of phenolic resin, modified phenolic resin, and glycidyl ether epoxy resin; (4) The oily fluorescent microsphere includes a fluorescent material, a shell layer coating the fluorescent material, and an oily ligand modified on the surface of the shell layer; (5) The oily sustained-release material can slowly dissolve and release in an oily solvent and can adhere to the surface of the support particles; (6) The curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products, cycloaliphatic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

3. The preparation method of the oily sustained-release tracer according to claim 2, characterized in that It includes one or more features selected from the following groups: (1) 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; (2) The oily sustained-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, and C9 petroleum resin and its derivatives.

4. The preparation method of the oily sustained-release tracer according to claim 1, characterized in that, The diluent can dissolve the oily sustained-release material and the oily fluorescent microsphere, has an epoxy group, and its viscosity ≤ 100 mPa·s.

5. The preparation method of the oil-based sustained-release tracer according to claim 4, characterized in that, The viscosity of the diluent ≤ 50 mPa·s; the diluent includes at least one of neodecanoic acid epoxyethyl methyl ester, C8 - C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy)propyl ether.

6. The preparation method of the oily sustained-release tracer according to claim 1, wherein In the reaction mixture, the mass ratio of the support particles is 85 - 98 wt%; in the premix, the mass ratio of the skeletal resin is 50 - 85 wt%, the mass ratio of the diluent is 7 - 40 wt%, the mass ratio of the oily sustained-release material is 2 - 20 wt%, and the mass ratio of the oily fluorescent microsphere is 1 - 8 wt%; in step S2, the mass ratio of the added premix to the curing agent is (2 - 10):

1.

7. The preparation method of the oily sustained-release tracer according to claim 1, wherein, In step S2, the premix and the curing agent are all added into the reaction equipment once, forming a slow-release layer; or the premix and the curing agent are added into the reaction equipment in multiple times, forming multiple slow-release layers.

8. The preparation method of the oily sustained-release tracer according to claim 7, characterized in that If the premix and the curing agent are added into the reaction equipment in multiple times, the amounts of the premix and the curing agent added each time and the mass ratios of the components are the same or different.

9. An oil-based sustained-release tracer, the oil-based sustained-release tracer comprising: Support particles and a slow-release layer coating the support particles, the slow-release layer comprising: a cross-linked reaction cured product of a diluent and a skeletal resin coated on the surface of the support particles, and oil-based fluorescent microspheres and oil-based slow-release materials distributed between the cured products.

10. The oil-based sustained-release tracer according to claim 9, characterized in that, Comprising one or more features selected from the following groups: (1) The support particles comprise at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles; (2) The skeletal resin comprises at least one of phenolic resin, modified phenolic resin, and glycidyl ether epoxy resin; (3) The diluent can dissolve the oil-based slow-release material and the oil-based fluorescent microspheres, has an epoxy group, and its viscosity ≤ 100 mPa·s; (4) The diluent comprises at least one of neodecanoic acid epoxyethyl methyl ester, C8-C10 alkyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, 2-phenyl glycidyl ether, nonylphenol glycidyl ether, or p-tert-butylphenyl 1-(2,3-epoxy)propyl ether; (5) The oil-based slow-release material can be slowly dissolved and released in an oil-based solvent and can adhere to the surface of the support particles; (6) The oil-based fluorescent microspheres comprise a fluorescent material, a shell layer coating the fluorescent material, and an oil-based ligand modified on the surface of the shell layer.

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