High-temperature-resistant tracking master batch

Abstract

According to the high-temperature-resistant tracking master batch provided by the invention, a composite structure is adopted, and the matrix layer is composed of the high-temperature-resistant engineering plastic and the inorganic reinforcing agent and has high temperature resistance and mechanical strength; the functional layer is a tracking unit dispersed in the matrix layer and comprises magnetic nanoparticles and a rare earth fluorescent material, and the interface bonding strength is improved through silanization treatment; the protective layer is a microcapsule formed by coating the tracking unit through a sol-gel method, the thermal expansion coefficient difference between the protective layer and the matrix is less than or equal to 10%, and the rupture rate during melt blending at 320 DEG C is less than or equal to 2%. The preparation method of the tracking master batch comprises the steps of high-temperature extrusion and water-cooling pelletizing. The fluorescence intensity attenuation rate of the tracking master batch is smaller than or equal to 5% at the temperature of 300 DEG C, and the tracking master batch is suitable for full-life-cycle tracking of engineering plastics.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a high-temperature resistant tracking masterbatch for full life cycle traceability of plastic products. Background Art

[0002] Tracking masterbatch, also known as tracer masterbatch or tracking masterbatch, is a functional particle created by combining an identifiable marker (such as a fluorescent agent, magnetic particles, or chemically coded substances) with a polymer matrix through specialized techniques. Its core function is to impart material traceability through physical or chemical means, and it is widely used in plastics, environmental recycling, and industrial product anti-counterfeiting.

[0003] Traditional methods of tracing masterbatches include introducing stable isotopes, such as carbon-13 and nitrogen-15, and then tracing the material composition and processing history through mass spectrometry analysis. Alternatively, specific functional groups are designed in the polymer chain segments for identification through infrared spectroscopy or chromatography. However, this type of tracing masterbatch is prone to failure or interference with the production process at processing temperatures above 240°C due to insufficient thermal stability with traditional labeling substances or deterioration of compatibility with the matrix. Specifically, isotope labeling may cause isotope exchange due to polymer chain breakage or oxidation reactions during high-temperature processing, resulting in an imbalance in the isotope ratio and large errors in mass spectrometry detection; characteristic functional groups undergo oxidation, cross-linking or chain scission at high temperatures, causing characteristic peaks in the infrared spectrum to shift or disappear.

[0004] Therefore, it is urgent to develop a high temperature resistant tracking masterbatch to overcome the above problems. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a tracking masterbatch that meets the processing temperature of engineering plastics, so as to achieve its tracking effect throughout the life cycle of plastic products. It has good high temperature resistance and is suitable for the processing of existing resin materials. The tracking signal is obvious and stable.

[0006] To achieve the above object, the present invention provides a technical solution, which is a high temperature resistant tracking masterbatch, comprising the following composite structure: Base layer: composed of high temperature resistant engineering plastics and inorganic reinforcing agents; Functional layer: Tracking units uniformly dispersed in the matrix layer, composed of at least one of magnetic nanoparticles or rare earth fluorescent materials; Protective layer: a microcapsule formed by encapsulating the tracking unit with ceramic and / or high-temperature resistant polymer.

[0007] Furthermore, the high-temperature-resistant engineering plastic in the base layer is selected from at least one of polyphenylene sulfide (PPS), polyetheretherketone (PEEK), and polyamide (PA). These engineering plastics all have melting temperatures >280°C and heat deformation temperatures >260°C, meeting high-temperature processing requirements. They constitute 85-94% of the base layer's mass. The inorganic reinforcing agent, selected from nano-boron nitride or silicon carbide, improves the base layer's thermal conductivity to reduce localized thermal stress, while also providing enhanced mechanical strength to the base resin and forming a physical barrier to isolate the tracking unit from the external environment. Its particle size ranges from 50-500nm and constitutes 6-15% of the base layer's mass.

[0008] Furthermore, the magnetic nanoparticles in the functional layer are neodymium iron boron (NdFeB) or ferrite (Fe3O4), coated with a 10-20nm thick silicon dioxide (SiO2) or aluminum oxide (Al2O3) coating to prevent the magnetic particles from oxidizing and losing their magnetism due to high-temperature oxidation while also reducing the difference in thermal expansion coefficient with the base material. The magnetic nanoparticles have a particle size of 10-100nm.

[0009] Furthermore, the rare earth fluorescent material of the functional layer is europium (Eu 3+ ) doped yttrium oxide (Y2O3) or terbium (Tb 3+ )-doped lanthanum phosphate (LaPO4); the rare earth fluorescent material has an excitation wavelength of 254-365nm and an emission wavelength of 500-700nm. It emits visible light when excited by ultraviolet light. Rare earth ion doping optimizes the lattice structure and reduces the half-width of the emission wavelength to less than 20nm, thereby improving the fluorescent material's resistance to ambient light interference.

[0010] Furthermore, the fluorescent material is subjected to surface silanization treatment to enhance the compatibility of the fluorescent material with the substrate, reduce the risk of interface peeling at high temperature, and enable the interface bonding strength between the fluorescent material and the substrate layer to be ≥50 MPa.

[0011] Furthermore, the dispersion density of the magnetic nanoparticles in the matrix layer is 10 4 -10 6 pieces / cm 3 The average spacing between microcapsules in the masterbatch is 1-10 μm, ensuring that the magnetic signal is uniform and measurable without the risk of agglomeration.

[0012] Furthermore, after the fluorescent material is continuously heated at 300° C. for 2 hours, the fluorescence intensity decay rate is ≤5%.

[0013] Furthermore, the difference in thermal expansion coefficient between the protective layer material and the base layer resin is ≤25%, to prevent microcapsule rupture due to thermal stress during processing. When the difference in thermal expansion coefficient is greater than 25%, according to certain embodiments, a gradient coating structure can be used to compensate for thermal stress.

[0014] Furthermore, the particle size of the microcapsules of the protective layer is 15-50 μm, and the thickness of the protective layer is 2-4 μm; the material of the protective layer is at least one of zirconium oxide (ZrO2), silicon nitride (Si3N4), and polyimide (PI); the protective layer is formed by a sol-gel method, and the ceramic precursor is selected from one of tetraethyl orthosilicate, zirconium nitrate, and silicon nitride sol; the microcapsules are obtained after the ceramic precursor is calcined in a calcination furnace at a temperature of 500-800 degrees Celsius and the calcination time is 1-4 hours.

[0015] Furthermore, when the microcapsules are melt-blended at 320 degrees Celsius, the breakage rate is ≤5%.

[0016] The present invention also provides a method for preparing a high-temperature resistant tracking masterbatch having at least one of the above items, comprising: S1: Blend the microcapsules and the matrix material in an extruder at an extrusion temperature of 280-320°C and a screw speed of 200-400 rpm; S2: The extruded microcapsules and the matrix material are water-cooled and pelletized. The particle size of the masterbatch is 2-5 mm and the density is 1.2-1.8 g / cm 3 .

[0017] For illustrative purposes, methods for measuring the dispersion density of magnetic nanoparticles include, but are not limited to, SEM image analysis using ImageJ software. Interface binding strength was measured using a micromechanical probe method. Fluorescence intensity was measured using a HORIBA FluoroMax-4, with an excitation wavelength of 365 nm and a power of 50 mW. The decay rate was calculated as [(I0-I) / I0] × 100%, where I0 is the initial fluorescence intensity and I is the fluorescence intensity after heating.

[0018] The advantages and beneficial effects of the present invention are: The base layer of the present invention is a composite of high-temperature resistant engineering plastics and nano-scale inorganic reinforcing agents. While ensuring the temperature resistance of the material, the inorganic reinforcing agents improve the mechanical strength and thermal stability, effectively isolating the damage of high temperature and shear force tracking masterbatch. At the same time, the coating on the surface of the magnetic nanoparticles can prevent demagnetization caused by high-temperature oxidation. The silanization treatment of the rare earth fluorescent material combined with the protective layer ensures that its fluorescence attenuation rate is ≤5%, which is significantly better than traditional fluorescent masterbatch.

[0019] The base layer material and the protective layer are made of materials with a thermal expansion coefficient difference of ≤10%, which can effectively avoid interface delamination or microcapsule rupture caused by thermal stress during processing. After surface coating, the oxidation resistance of magnetic nanoparticles is greatly improved. The rare earth fluorescent material is optimized by doping the excitation-emission wavelength, and can still maintain signal stability in complex environments. The service life covers the entire life cycle of plastic products.

[0020] The sol-gel method combined with a calcination process allows for precise control of the protective layer's thickness and density, achieving a ceramic precursor conversion rate of ≥95%. The extruder in the blending process matches the microcapsule's temperature tolerance threshold to prevent melting or degradation of the functional layer. Magnetic particles and fluorescent materials can be used individually or in combination, supporting multimodal tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of the tracking masterbatch of the present invention; In the figure: 1-base layer, 2-functional layer, 3-protective layer. DETAILED DESCRIPTION

[0022] This invention provides a high-temperature-resistant tracking masterbatch. The base layer 1 is constructed of engineering plastics such as polyphenylene sulfide and polyetheretherketone, creating a high-temperature stable main frame. Inorganic reinforcing agents and high-thermal-conductivity inorganic fillers are introduced to reduce local temperature gradients during processing, thereby increasing the base layer's flexural modulus and resisting shear forces during melt blending.

[0023] The functional layer 2 of the masterbatch can be equipped with a magnetic signal unit or a fluorescent signal unit. The surface of the magnetic signal unit is coated with ceramic particles to increase the Curie temperature, thereby increasing its oxidation resistance temperature; the fluorescent signal unit increases the fluorescence quantum yield by doping the fluorescent lattice. 3+ Formation of [PO4] in the LaPO4 lattice 3- →Tb 3+ energy transfer channel, and the excited state lifetime is extended.

[0024] Nano-boron nitride forms a heat-conducting network by stacking layers, reducing the temperature gradient around the microcapsule, and synergistically suppressing the accumulation of thermal stress with the low thermal expansion characteristics of the ceramic protective layer, thereby reducing the tracking signal attenuation after multiple cycles.

[0025] The fluorescent particles are modified with a silane coupling agent. After hydrolysis, the silane coupling agent forms Si-OY covalent bonds with the hydroxyl groups on the surface of the fluorescent particles, thereby increasing the interface bonding strength from 30MPa to ≥50MPa. The thermal decomposition temperature of the silane layer at 300°C is greater than 400°C, which can effectively block the erosion of the fluorescent material by the thermal degradation products of the matrix resin.

[0026] According to some embodiments, the overall thermal stress can be reduced by introducing a polyimide intermediate layer between the substrate and the ceramic protective layer 3. Adjusting the shell thickness can also increase the rupture pressure threshold of the microcapsules at 320°C.

[0027] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] Example 1 A high temperature resistant tracking masterbatch comprising: The base layer comprises, by weight, 90% polyphenylene sulfide and 10% nano-boron nitride with a particle size of 200 nm; Functional layer, ferrite magnetic particles with a particle size of 50nm and coated with 10nm SiO2, the dispersion density of which in the masterbatch is 1×10 5 pieces / cm 3 .

[0029] The protective layer is a polyimide microcapsule covering the functional layer, with a particle size of 15 μm and a thickness of 2 μm. The average spacing between the microcapsules in the masterbatch is 8 μm.

[0030] The preparation process comprises the following steps: S1, microcapsule preparation: ferrite particles were immersed in a polyamic acid precursor solution, and the temperature was gradually increased to 300°C to form a PI coating layer; the solid content of the polyamic acid precursor solution was 15 wt%, and the temperature was gradually increased from room temperature to 300°C at 5°C / min; S2, blending extrusion: The PI-coated material obtained in S1 was transferred to a twin-screw extruder. The extruder temperature was set at 300°C and the screw speed was 300 rpm. The pellets were water-cooled and pelletized to obtain a particle size of 3 mm and a density of 1.5 g / cm 3 High temperature resistant tracking masterbatch.

[0031] The thermal expansion coefficient of the substrate layer is 45×10 -6 / K, the thermal expansion coefficient of the protective layer is 50×10 -6 / K, the difference in thermal expansion coefficient is ≈10%, and the microcapsule rupture rate is 1.8% after melt processing at 320℃ for 5min.

[0032] Example 2 A high temperature resistant tracking masterbatch comprising: Matrix layer: By weight, polyetheretherketone (PEEK) accounts for 88%, and silicon carbide with a particle size of 300nm accounts for 12%; Functional layer: Neodymium iron boron (NdFeB) magnetic particles with a particle size of 80nm and coated with a 15nm Al2O3 coating. The dispersion density in the masterbatch is 5×10 5 / cm³, Protective layer: Zirconia (ZrO2) microcapsules, coated with the functional layer using the sol-gel method, calcined at 650°C for 3 hours, with a microcapsule particle size of 20 μm and a thickness of 1.5 μm. The average spacing between the microcapsules in the masterbatch is 5 μm; The preparation process includes the following steps: S1, microcapsule preparation: NdFeB particles are impregnated in a zirconium nitrate precursor solution, subjected to a hydrolysis-polycondensation reaction, and then calcined to obtain a ZrO2 coating layer. The ZrO2 conversion rate after calcination is ≥95%; the solid content of the zirconium nitrate precursor solution is 10wt%; S2, blending and extrusion: The microcapsules prepared in S1 were blended with the matrix material in a twin-screw extruder, with the temperature set at 310°C and the screw speed at 350 rpm. The extruder was water-cooled and pelletized to obtain a masterbatch with a particle size of 3.5 mm.

[0033] The thermal expansion coefficient of the substrate layer is 50×10 -6 / K, the thermal expansion coefficient of the protective layer is 10×10 -6 / K, the difference is ≈80%. The microcapsule rupture rate is 5% after melt processing at 320℃ for 5 minutes.

[0034] Example 3 A high temperature resistant tracking masterbatch comprising: Base layer: By weight, polyamide (PA46) accounts for 92%, and nano-boron nitride with a particle size of 100nm accounts for 8%; Functional layer: Europium-doped yttrium oxide (Y2O3:Eu 3+ ) fluorescent particles, with an excitation wavelength of 365 nm and an emission wavelength of 613 nm, and an APTES silanization treatment to form a 3 nm thick coupling layer; Protective layer: Silicon nitride (Si3N4) microcapsules, particle size 10μm, thickness 0.8μm. The average spacing between microcapsules in the masterbatch is 1μm.

[0035] The preparation process includes the following steps: S1, surface modification: europium-doped yttrium oxide particles reacted with γ-aminopropyltriethoxysilane and ultrasonicated at 50 °C for 2 h; S2, protective layer preparation: silanized Y2O3:Eu 3+ The particles were impregnated with a silicon nitride (10 wt%) sol precursor and calcined at 600 °C for 2.5 h to form a Si3N4 coating layer, with a precursor conversion rate of 96%.

[0036] S2, blending and extrusion: the modified fluorescent particles and the matrix material are melt-blended in a twin-screw extruder, the temperature is set at 290°C, the screw speed is 280 rpm, and the pelletizing is carried out by water cooling to obtain a masterbatch with a particle size of 2.8 mm.

[0037] The thermal expansion coefficient of the substrate layer is 60×10 -6 / K, the thermal expansion coefficient of the protective layer silicon nitride is 3.2×10 -6 / K, and the interfacial bonding strength increased to 52MPa after silanization treatment. After continuous heating at 300℃ for 2 hours, the fluorescence intensity decay rate was measured to be 4.7%, and the rupture rate of the microcapsules when melted at 320℃ for 5 minutes was 1.2%.

[0038] Example 4 A high temperature resistant tracking masterbatch, comprising: Matrix layer: By weight percentage, PPS / PEEK blend (7:3) accounts for 85%, and silicon carbide with a particle size of 400nm accounts for 15%; Functional layer: dual-mode tracking unit (Fe3O4@SiO2 with a particle size of 10nm and LaPO4:Tb 3+ Mixed in a 1:1 ratio by weight); Protective layer: Silicon nitride microcapsules, particle size 25μm, thickness 3μm. The average spacing between microcapsules in the masterbatch is 8μm.

[0039] The preparation process includes the following steps: S1, microcapsule drying: Fe3O4@SiO2 particles were treated with γ-methacryloxypropyltrimethoxysilane; LaPO4:Tb 3+ The particles were modified with 3-aminopropyltriethoxysilane, and the interfacial bonding strength of the two tracking units mixed with the matrix resin reached 55 MPa; The functional layer particles were vacuum dried (120℃×4h, moisture content ≤0.1%) S2, blending and extrusion: the dried microcapsules are blended with the matrix material, the extrusion temperature is 320°C, the screw speed is 400 rpm, the melt flow rate is controlled at 12 g / 10 min, and the water-cooled pelletizing particle size is 4 mm.

[0040] Thermal expansion coefficient of substrate layer (PPS / PEEK) 55×10 -6 / K, the thermal expansion coefficient difference of the protective layer silicon nitride is 40×10 -6 / K, but through the gradient coating structure, it was melted at 320℃ for 5min, and the actual rupture rate was 1.8%.

[0041] Example 5 A high temperature resistant tracking masterbatch, comprising: Base layer: By weight percentage, polyamide (PI) accounts for 94%, and nano-boron nitride with a particle size of 50nm accounts for 6%; Functional layer: dual-functional system (100nm NdFeB@Al2O3 and Y2O3:Eu 3+ The tracking unit is dispersed in the matrix at a density of 10×10 5 / cm³, average spacing 2.8μm; Protective layer: ZrO2 / polyimide composite microcapsules, using three layers of alternating deposition to form a ZrO2 / PI / ZrO2 capsule shell, with a particle size of 50μm and a total thickness of 4μm. The average spacing between microcapsules in the masterbatch is 10μm.

[0042] The preparation process includes the following steps: S1, composite coating: ZrO2 and PI layers were alternately deposited by sol-gel method. The inner ZrO2 layer was prepared by zirconium nitrate precursor and calcined at 550℃ for 1 hour. The middle PI layer was spin-coated with polyamic acid solution and imidized at 300℃. The outer ZrO2 layer was prepared by tetraethyl orthosilicate precursor and calcined at 00℃ in a muffle furnace for 1.5h. S2, co-extrusion: the functional layer and the base material were co-extruded in a twin-screw extruder with the temperature set at 330°C and the screw speed at 250 rpm. The masterbatch with a particle size of 5 mm was obtained by water-cooling and pelletizing.

[0043] Overall thermal expansion coefficient of protective layer: 35×10 -6 / K (the base layer PI is 45×10 -6 / K), the difference is ≈20%, but through the flexible PI intermediate layer for buffering, the crack rate is only 1.5% when processed at 320℃ for 5min.

[0044] Each of the above examples was added to PPS at a weight percentage of 10% and injection molded at 320 degrees Celsius into standard 5cm*2cm*0.5cm splines. The tracking signal was detected for each example, and the splines were then crushed and injection molded again. This cycle was repeated three times. The results showed that the tracking signal retention rate of each example after each cycle was ≥95%.

[0045] Comparative Example 1 The only difference from Example 2 is that the microcapsule structure without a protective layer has a magnetization loss rate of 40-50% after 3 cycles.

[0046] Comparative Example 2 The only difference from Example 5 is that the structure without a protective layer has a fluorescence decay rate of 15-20% after 3 cycles.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high temperature resistant tracking masterbatch, characterized in that: The following composite structures are included: Base layer: composed of high temperature resistant engineering plastics and inorganic reinforcing agents; Functional layer: Tracking units uniformly dispersed in the matrix layer, composed of at least one of magnetic nanoparticles or rare earth fluorescent materials; Protective layer: a microcapsule formed by coating the tracking unit with ceramic and / or high-temperature resistant polymer.

2. The high temperature resistant tracking masterbatch according to claim 1, characterized in that: The high-temperature resistant engineering plastic in the base layer is selected from at least one of polyphenylene sulfide, polyetheretherketone, and polyamide, and accounts for 85-94% of the mass of the base layer; The inorganic reinforcing agent is nano boron nitride or silicon carbide with a particle size of 50-500 nm, accounting for 6-15% of the mass of the base layer.

3. The high temperature resistant tracking masterbatch according to claim 1, characterized in that: The magnetic nanoparticles of the functional layer are neodymium iron boron or ferrite, and the surface is coated with a silicon dioxide or aluminum oxide coating with a thickness of 10-20nm; The particle size of the magnetic nanoparticles is 10-100 nm.

4. The high temperature resistant tracking masterbatch according to claim 1, characterized in that The rare earth fluorescent material is europium-doped yttrium oxide or terbium-doped lanthanum phosphate; The excitation wavelength of the rare earth fluorescent material is 254-365 nm, and the emission wavelength is 500-700 nm.

5. The high temperature resistant tracking masterbatch according to claim 1, characterized in that: The particle size of the microcapsules in the protective layer is 15-50 μm, and the thickness of the protective layer is 2-4 μm; The protective layer material is at least one of zirconium oxide, silicon nitride and polyimide.

6. The high temperature resistant tracking masterbatch according to claim 1, characterized in that: The protective layer is formed by a sol-gel method, and the ceramic precursor is selected from one of tetraethyl orthosilicate, zirconium nitrate, and silicon nitride sol; The calcination temperature is 500-800 degrees Celsius, and the calcination time is 1-4 hours.

7. The high temperature resistant tracking masterbatch according to claim 3, characterized in that: The dispersion density of the magnetic nanoparticles in the matrix layer is 10 4 -10 6 pieces / cm 3 ; The average spacing between microcapsules in the masterbatch is 1-10μm.

8. The high temperature resistant tracking masterbatch according to claim 4, characterized in that: The fluorescent material is subjected to surface silanization treatment, and the interface bonding strength with the substrate layer is ≥50MPa; After the fluorescent material is continuously heated at 300° C. for 2 hours, the fluorescence intensity decay rate is ≤5%.

9. The high temperature resistant tracking masterbatch according to claim 1, characterized in that: The preparation method comprises: S1: Blend the microcapsules and the matrix material in an extruder at an extrusion temperature of 280-320°C and a screw speed of 200-400 rpm; S2: The extruded microcapsules and the matrix material are water-cooled and pelletized. The particle size of the masterbatch is 2-5 mm and the density is 1.2-1.8 g / cm3.

10. The high temperature resistant tracking masterbatch according to claim 5, characterized in that: The difference in thermal expansion coefficient between the protective layer material and the base layer resin is ≤25%; When the microcapsules are melt-blended at 320 degrees Celsius, the breakage rate is ≤5%.

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