Flame-retardant ABS plastic raw material and preparation method thereof

Abstract

The present application relates to the technical field of plastic raw materials, and particularly relates to a flame-retardant ABS plastic raw material and a preparation method thereof, which comprises the following components in parts by weight: ABS base resin 80 parts, heat-controlled release microcapsules 15 parts, and interfacial compatibilizer 5 parts; the heat-controlled release microcapsules comprise a bromine radical capturing agent and a molecular sieve smoke adsorbent, and the heat-controlled release microcapsules have a polyphenylene sulfide shell. The present application adopts an innovative microcapsule size and molecular sieve loading synergistic optimization strategy, under the premise of reducing the amount of microcapsules, compared with the traditional high-filling method, by using 20 microns of microcapsules to increase the specific surface area, 80% of ZIF-IL@PW to strengthen the pore adsorption, and only smoke density 72 to maintain the top smoke suppression level, the material cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plastic raw materials, in particular to a flame-retardant ABS plastic raw material and a preparation method thereof. BACKGROUND

[0002] ABS is a kind of thermoplastic plastic with excellent comprehensive performance. It is widely used in automobile parts, electronic and electrical appliances, household appliances and other fields due to its good mechanical strength, impact resistance, processing fluidity and surface gloss.

[0003] The mainstream preparation method of plastic raw materials at present adopts physical blending modification method. ABS resin particles and flame retardants are melt blended and extruded into particles in a twin-screw extruder. Commonly used flame retardants include decabromodiphenyl ether, tetrabromobisphenol A and other bromine-based flame retardants. Flame retardants decompose to produce free radical trapping agents (bromine radicals) at high temperatures, interrupting the combustion chain reaction. However, bromine-based flame retardants will decompose at high temperatures of 250-350℃, releasing active bromine radicals. These radicals react with polymer chains to generate hydrogen halide gas, and also produce highly toxic brominated dioxin byproducts. The released hydrogen halide gas is highly corrosive and irritating, and can cause respiratory tract burns, chemical pneumonia, and even pulmonary edema and asphyxia after being inhaled by the human body. Persistent organic pollutants such as dioxins have high toxicity and bioaccumulation, and long-term exposure can interfere with the endocrine system, damage immune function, and significantly increase the risk of cancer

[0004] Therefore, a flame-retardant ABS plastic raw material and a preparation method thereof are proposed to solve the above problems. SUMMARY

[0005] Technical problems to be solved

[0006] In view of the above-mentioned shortcomings of the prior art, the present application provides a flame-retardant ABS plastic raw material and a preparation method thereof, which can effectively solve the problem of the contradiction between the release of toxic smoke and the mechanical property decay of traditional flame-retardant ABS in the prior art.

[0007] Technical scheme

[0008] To achieve the above purpose, the present application is realized by the following technical scheme:

[0009] The present application provides a flame-retardant ABS plastic raw material, which comprises the following components by weight:

[0010] ABS base resin 80 parts, heat-controlled release microcapsule 5 parts, and interfacial compatibilizer 15 parts;

[0011] The heat-controlled release microcapsule contains bromine radical trapping agent and molecular sieve smoke adsorbent, and the heat-controlled release microcapsule has a polyphenylene sulfide shell.

[0012] Further, the bromine radical scavenger is a complex of phosphotungstic acid and 1-vinyl-3-ethylimidazole tetrafluoroborate with a molar ratio of 3:1, and is crosslinked by ultraviolet radiation.

[0013] Further, the molecular sieve toxic fume adsorbent is a complex of ZIF-8 nanoparticles and the bromine radical scavenger with a mass ratio of 1:1.5.

[0014] Further, the thermal controlled release microcapsule has a diameter of 20 microns, and the mass ratio of the ZIF-8 nanoparticles and the bromine radical scavenger composite powder encapsulated inside is 80%.

[0015] Further, the interfacial compatibilizer is a maleic anhydride modified elastomer.

[0016] A preparation method of a flame-retardant ABS plastic raw material, comprising the following steps:

[0017] Step one: phosphotungstic acid and 1-vinyl-3-ethylimidazole tetrafluoroborate are reacted at a molar ratio of 3:1 at 60°C for 2 hours, and then crosslinked by ultraviolet radiation for 45-75 minutes;

[0018] Step two: the product of step one is added to methanol, and 0.1wt% polyvinylpyrrolidone is added as a dispersant for mixing;

[0019] Step three: ZIF-8 nanoparticles and the product of step two are solvothermal self-assembled at a mass ratio of 1:1.5 in methanol at 100°C;

[0020] Step four: the product of step three is encapsulated in a polyphenylene sulfide shell, and phase separation is induced at a cooling rate of 2-3°C / min;

[0021] Step five: ABS resin, interfacial compatibilizer and thermal controlled release microcapsule are melt blended in a twin-screw extruder, and then extruded and granulated.

[0022] Further, the melt blending in step five includes:

[0023] The ABS resin is melt plasticized at a first temperature zone of 165°C and a rotation speed of 220 rpm;

[0024] An interpenetrating network premix body is formed at a second temperature zone of 175°C and a rotation speed of 220 rpm;

[0025] A covalent bond between the matrix and the microcapsule is formed at a third temperature zone of 185-205°C and a rotation speed of 200-250 rpm;

[0026] The extrusion and granulation are performed at a fourth temperature zone of 185°C and a rotation speed of 220 rpm.

[0027] Further, the crosslinking time under ultraviolet radiation in step one is 60 minutes.

[0028] Further, the cooling rate in step three is 3℃ / min.

[0029] Further, the third temperature zone in step five is 205℃, and the rotation speed is 250rpm.

[0030] Beneficial effects

[0031] The technical solution provided by the present application has the following beneficial effects compared with the prior art:

[0032] The present application adopts a microcapsule size and molecular sieve load synergistic optimization strategy, under the premise of reducing the amount of microcapsules, compared with the traditional high filling method, by increasing the specific surface area of 20pm microcapsules, 80% ZIF-IL@PW load adsorption, only with smoke density 72 to maintain the top smoke suppression level, realize the reduction of material cost.

[0033] In addition, on the mechanical strength level, the interfacial compatibilizer is innovatively improved to 15%, and the covalent bond network is constructed at the molecular scale, so that the tensile strength reaches 40MPa, which is better than the traditional method, and the problem of weakening of the matrix by the flame retardant is solved.

[0034] And through the breakthrough of processing stability, the extrusion parameters are precisely controlled, and the microcapsule integrity rate reaches 99% under the ultra-high shear field, solving the world-wide problem of processing loss of nano-functional components. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0036] Figure 1 SEM microstructure diagram of the flame-retardant ABS particles prepared in the examples and comparative examples of the present application;

[0037] Figure 2 Experimental table of the flame-retardant ABS particles prepared in the examples and comparative examples of the present application. DETAILED DESCRIPTION

[0038] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] The present application will be further described below with reference to the embodiments.

[0040] Embodiment one:

[0041] The present application proposes a flame-retardant ABS plastic raw material, which comprises the following components by weight:

[0042] ABS base resin 80 parts, heat-controlled release microcapsules 10 parts, and interfacial compatibilizer 10 parts.

[0043] The ABS base resin is acrylonitrile-butadiene-styrene terpolymer, which is used as the main material structure to provide mechanical strength, processing fluidity and surface finish. Acrylonitrile (A) is used to impart chemical resistance, butadiene (B) is used to provide toughness, and styrene (S) is used to ensure processing fluidity. In the flame-retardant system, it is used as a carrier to make the functional components uniformly dispersed and play a synergistic effect.

[0044] The heat-controlled release microcapsules are composed of a bromine radical scavenger and a molecular sieve smoke adsorbent, wherein:

[0045] The bromine radical scavenger is a phosphotungstic acid and ionic liquid composite. The core structure of phosphotungstic acid has a special electron hole, which can efficiently capture bromine radicals generated in high-temperature cracking. The ionic liquid is used as a carrier to make it stably dispersed in the matrix. After the two are compounded, bromine radicals can be captured and forced to convert into stable ionic state, thereby cutting off the reaction chain of bromine radicals participating in the generation of highly toxic dioxins from the source.

[0046] The molecular sieve smoke adsorbent is a zeolite imidazolate framework nanoparticle. By using its nanoscale pore structure (pore size slightly smaller than the size of benzene ring), it selectively adsorbs small molecules with benzene ring structure (dioxin precursors) generated during combustion through physical screening effect. The chemical sites on the surface of the crystal framework can strengthen the electrostatic locking of toxic smoke molecules, realizing the dual-trapping mechanism of size matching and chemical adsorption.

[0047] The microcapsule controlled-release shell is a polyphenylene sulfide polymer material, which serves as a protective layer for the functional core (molecular sieve + capture agent) and maintains the complete structure at the processing temperature (about 200°C) to avoid premature decomposition of the functional components. When the material reaches the critical combustion temperature (above 300°C), the shell suddenly melts and releases the contents, forming a temperature-triggered intelligent release gate, ensuring that the functional components are activated only in a fire scenario.

[0048] The interfacial compatibilizer is a maleic anhydride modified elastomer, with anhydride groups in the molecular chain chemically bonded to the ABS matrix, while the hydrophobic segment covers the microcapsule surface. Through the bridge effect, the interfacial repulsion between the microcapsule and ABS is eliminated, preventing the microcapsule from aggregating into groups and achieving uniform dispersion at the nanoscale. The flexible segment can also buffer material stress, improving the impact toughness of the final product.

[0049] A flame-retardant ABS plastic raw material, the preparation method comprising the following steps:

[0050] Step one: Place phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate in a constant temperature stirring reaction kettle according to a molar ratio of 3:1, and perform liquid phase electrostatic complexation reaction at 60°C environment, continuously stirring for 2 hours. Then transfer to the ultraviolet reaction chamber, use ultraviolet light source with wavelength of 254 nanometers for radiation crosslinking, light intensity control at 20 milliwatts per square centimeter, continuous illumination for 60 minutes. Obtain yellow powder of bromine free radical capture agent, powder particle size uniformly distributed at about 0.8 microns.

[0051] Step two: gradually add free radical capture agent powder particles into methanol, and continuously stir at room temperature 25 with a rotation speed of 400 rpm, and add 0.1wt% polyvinylpyrrolidone as dispersant, to prepare 15wt% white suspension of free radical capture agent powder particles, namely IL-PW methanol suspension.

[0052] Step three: put ZIF-8 nanoparticles and IL-PW methanol suspension into a microwave reactor with a mass ratio of 1:1.2, and perform solvothermal self-assembly reaction at 100°C environment. After the reaction is completed, transfer to a centrifuge and use methanol solvent for three times of centrifugal washing and purification to form ZIF-IL@PW composite powder with core-shell structure, namely molecular sieve smoke adsorbent, with an inner core diameter of about 50 nanometers and a uniformly coated IL-PW shell layer with a thickness of 5 nanometers.

[0053] Step four: put polyphenylene sulfide solution into a constant temperature water bath at 70°C to dissolve and form an oil phase solution, then disperse ZIF-IL@PW composite powder therein, and transfer to a water bath environment at 25°C to induce phase separation at a rate of 2°C per minute, to obtain spherical microcapsule particles, namely thermal controlled-release microcapsules, with a diameter of about 35 microns and an internal encapsulated ZIF-IL@PW composite powder mass ratio of 65%.

[0054] Step five: Put ABS resin particles 80 parts and interfacial compatibilizer 10 parts prepared in step three, and thermal controlled release microcapsules 10 parts prepared in step four into a twin-screw extruder, and perform segmented temperature control processing:

[0055] Set the first temperature zone at 165°C and 220 rpm to melt and plasticize ABS resin;

[0056] Set the second temperature zone at 175°C and 220 rpm to dissociate the interfacial compatibilizer, expose the active carboxyl group, and form an interpenetrating network premixing body of the molten and plasticized ABS resin and the dissociated interfacial compatibilizer under the action of screw shear force;

[0057] Set the third temperature zone at 195°C and 220 rpm, and the maleic anhydride groups of the interfacial compatibilizer undergo ring-opening reaction with the polyphenylene sulfide shell on the surface of the thermal controlled release microcapsules to form covalent bond connection between the matrix and the microcapsules.

[0058] Set the fourth temperature zone at 185°C and 220 rpm, and under constant pressure, the melt is extruded through a die, passes through a water-cooled draw bar, and is cut by a granulator to form beige uniform particles, i.e., flame-retardant ABS particles.

[0059] Example two:

[0060] The present application proposes a preparation method of flame-retardant ABS plastic raw material, which comprises the following steps:

[0061] Step one: Place phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate in a constant temperature stirring reaction kettle according to a molar ratio of 3:1, and perform liquid phase electrostatic complexation reaction at 60°C environment, continuously stirring for 2 hours. Then transfer to an ultraviolet reaction chamber, and use a 254 nanometer wavelength ultraviolet light source to perform radiation crosslinking, with light intensity controlled at 20 milliwatts per square centimeter, and continuously irradiated for 75 minutes. Obtain yellow powder bromine radical trapping agent, with powder particle size uniformly distributed at about 0.8 microns.

[0062] Step two: Gradually add the free radical trapping agent powder particles into methanol, and continuously stir at room temperature 25 with a rotation speed of 400 rpm, and add 0.1wt% polyvinylpyrrolidone as a dispersant to prepare a milky white suspension of 15wt% free radical trapping agent powder particles, i.e., IL-PW methanol suspension.

[0063] Step three: Put ZIF-8 nanoparticles and IL-PW methanol suspension with a mass ratio of 1:1 into a microwave reactor, and perform a solvothermal self-assembly reaction at 100°C. After the reaction is completed, transfer it to a centrifuge and use methanol solvent for three times of centrifugal washing and purification to form a ZIF-IL@PW composite powder with a core-shell structure, i.e. a molecular sieve smoke adsorbent, with an inner core diameter of about 50 nanometers and a uniform IL-PW shell layer with a thickness of 5 nanometers.

[0064] Step four: Put the polyphenylene sulfide solution into a constant temperature water bath at 70°C to dissolve and form an oil phase solution, then disperse the ZIF-IL@PW composite powder into it. Then transfer it to a water bath environment at 25°C to induce phase separation at a rate of 2°C per minute to obtain spherical microcapsule particles, i.e. thermal control release microcapsules, with a diameter of about 35 microns and an internal encapsulated ZIF-IL@PW composite powder mass ratio of 75%.

[0065] Step five: Put 75 parts of ABS resin particles, 10 parts of the interfacial compatibilizer prepared in step three, and 15 parts of the thermal control release microcapsules prepared in step four into a twin-screw extruder and perform segmented temperature control processing:

[0066] Set the first temperature zone to 165°C and 220 rpm to melt and plasticize the ABS resin;

[0067] Set the second temperature zone to 175°C and 220 rpm to dissociate the interfacial compatibilizer, expose the active carboxyl groups, and form an interpenetrating network premix body under the action of screw shear between the melted and plasticized ABS resin and the dissociated interfacial compatibilizer;

[0068] Set the third temperature zone to 200°C and 240 rpm to form a covalent bond between the maleic anhydride groups of the interfacial compatibilizer and the polyphenylene sulfide shell on the surface of the thermal control release microcapsule.

[0069] Set the fourth temperature zone to 185°C and 220 rpm under constant pressure, and after the melt is extruded through the die, it is cooled by a water-cooled draw bar and then cut by a pelletizer to form uniform beige particles, i.e. flame-retardant ABS particles.

[0070] Example three:

[0071] A preparation method of a flame-retardant ABS plastic raw material, which comprises the following steps:

[0072] Step one: Put phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate in a constant temperature stirring reactor according to a 3:1 molar ratio, and conduct liquid phase electrostatic complexation reaction at 60°C. Stir for 2 hours, then transfer to a UV reaction chamber and use a 254 nm wavelength UV light source for radiation crosslinking. The light intensity is controlled at 20 mW / cm2, and the irradiation time is 60 minutes. A yellow powder of bromine radical trapping agent is obtained, with a uniform powder particle size of about 0.8 microns.

[0073] Step two: Add the radical trapping agent powder particles to methanol gradually, and stir at room temperature at a speed of 400 rpm. Add 0.1 wt% polyvinylpyrrolidone as a dispersant to prepare a 15 wt% white suspension of radical trapping agent powder particles, namely IL-PW methanol suspension.

[0074] Step three: Put ZIF-8 nanoparticles and IL-PW methanol suspension in a microwave reactor according to a mass ratio of 1:1.5, and conduct solvothermal self-assembly reaction at 100°C. After the reaction is completed, transfer to a centrifuge and use methanol solvent for three times of centrifugal washing and purification to form a ZIF-IL@PW composite powder with a core-shell structure, namely a molecular sieve smoke adsorbent, with an inner core diameter of about 50 nanometers and a uniform IL-PW shell layer with a thickness of 5 nanometers.

[0075] Step four: Put the polyphenylene sulfide solution into a 70°C constant temperature water bath to dissolve and form an oil phase solution, then disperse the ZIF-IL@PW composite powder therein, and transfer to a 25°C water bath environment to induce phase separation at a rate of 3°C per minute to obtain spherical microcapsule particles, namely thermal control release microcapsules, with a diameter of about 20 microns and an internal encapsulation of ZIF-IL@PW composite powder with a mass ratio of 80%.

[0076] Step five: Put 80 parts of ABS resin particles, 15 parts of the interfacial compatibilizer prepared in step three, and 5 parts of the thermal control release microcapsules prepared in step four into a twin-screw extruder, and conduct segmented temperature control processing:

[0077] Set the first temperature zone to 165°C and 220 rpm to melt and plasticize the ABS resin;

[0078] Set the second temperature zone to 175°C and 220 rpm to dissociate the interfacial compatibilizer, expose the active carboxyl groups, and form an interpenetrating network premix body under the action of screw shear between the melted and plasticized ABS resin and the dissociated interfacial compatibilizer;

[0079] Set the third temperature zone to 205°C and 250 rpm, and the maleic anhydride groups of the interfacial compatibilizer react with the polyphenylene sulfide shell on the surface of the thermal control release microcapsule to form a covalent bond between the matrix and the microcapsule.

[0080] In the fourth temperature zone, set at 185℃, 220 rpm, under constant pressure, the melt was extruded through the die, then passed through a water-cooled draw-down bar, and then cut by a granulator to form beige uniform particles, i.e. flame-retardant ABS particles.

[0081] Example Four:

[0082] A preparation method of a flame-retardant ABS plastic raw material, which comprises the following steps:

[0083] Step one: Place phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate in a constant temperature stirring reaction kettle according to a molar ratio of 3:1, and perform liquid phase electrostatic complexation reaction at 60℃ environment, continuously stirring for 2 hours. Then transfer to an ultraviolet reaction chamber, and use a 254 nanometer wavelength ultraviolet light source for radiation crosslinking, with light intensity controlled at 20 milliwatts per square centimeter, and continuously irradiated for 45 minutes. Obtain yellow powder bromine radical trapping agent, with powder particle size uniformly distributed at about 0.8 microns.

[0084] Step two: Gradually add the free radical trapping agent powder particles into methanol, and continuously stir at a rotation speed of 400 rpm at room temperature, and add 0.1wt% polyvinylpyrrolidone as a dispersant, to prepare a 15wt% white suspension of free radical trapping agent powder particles, i.e. IL-PW methanol suspension.

[0085] Step three: Put ZIF-8 nanoparticles and IL-PW methanol suspension into a microwave reactor according to a mass ratio of 1:1.2, and perform solvothermal self-assembly reaction at 100℃ environment. After the reaction is completed, transfer to a centrifuge, and use methanol solvent for three times of centrifugal washing and purification, to form ZIF-IL@PW composite powder with core-shell structure, i.e. molecular sieve smoke adsorbent, with an inner core diameter of about 50 nanometers and a uniformly coated IL-PW shell layer of 5 nanometers in thickness.

[0086] Step four: Put the polyphenylene sulfide solution into a constant temperature water bath at 70℃ to dissolve and form an oil phase solution, then disperse the ZIF-IL@PW composite powder therein, and transfer to a water bath environment at 25℃ to induce phase separation at a cooling rate of 4℃ per minute, to obtain spherical microcapsule particles, i.e. thermal controlled release microcapsules, with a diameter of about 15 microns and an internal encapsulated ZIF-IL@PW composite powder mass ratio of 70%.

[0087] Step five: Put 70 parts of ABS resin particles, 10 parts of the interfacial compatibilizer prepared in step three, and 20 parts of the thermal controlled release microcapsules prepared in step four into a twin-screw extruder, and perform segmented temperature control processing:

[0088] In the first temperature zone, set at 165℃, 220 rpm, for melting and plasticizing ABS resin;

[0089] In the second temperature zone, set at 175℃, 220rpm, the plasticized ABS resin, which is exposed to the interfacial compatibilizer, is used to dissociate the interfacial compatibilizer, expose the active carboxyl groups, and melt under the action of screw shear force, and the plasticized ABS resin and the dissociated interfacial compatibilizer form an interpenetrating network premixing body;

[0090] In the third temperature zone, set at 195℃, 220rpm, the maleic anhydride groups of the interfacial compatibilizer and the polyphenylene sulfide shell on the surface of the heat-controlled release microcapsule undergo ring-opening reaction to form covalent bond connection between the matrix and the microcapsule.

[0091] In the fourth temperature zone, set at 185℃, 220rpm, under constant pressure, the melt is extruded through the die, passes through the water-cooled drag, and is cut by the granulator to form beige uniform particles, i.e. flame-retardant ABS particles.

[0092] Example Five:

[0093] A preparation method of a flame-retardant ABS plastic raw material, which comprises the following steps:

[0094] Step one: place phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate in a constant temperature stirring reaction kettle according to a molar ratio of 3:1, and perform liquid phase electrostatic complexation reaction at 60℃ environment, continuously stirring for 2 hours. Then transfer to the ultraviolet reaction chamber, and use a 254 nanometer wavelength ultraviolet light source for radiation crosslinking, with light intensity controlled at 20 milliwatts per square centimeter, and continuously irradiated for 45 minutes. Obtain yellow powder bromine radical trapping agent, with powder particle size uniformly distributed at about 0.8 microns.

[0095] Step two: gradually add the free radical trapping agent powder particles into methanol, and continuously stir at room temperature 25 with a rotation speed of 400 rpm, and add 0.1wt% polyvinylpyrrolidone as a dispersant to prepare a milky white suspension with a free radical trapping agent powder particle content of 15wt%, i.e. IL-PW methanol suspension.

[0096] Step three: place ZIF-8 nanoparticles and IL-PW methanol suspension in a microwave reactor according to a mass ratio of 1:0.8, and perform solvothermal self-assembly reaction at 100℃ environment. After the reaction is completed, transfer to a centrifuge, and use methanol solvent for three times of centrifugal washing and purification to form ZIF-IL@PW composite powder with core-shell structure, i.e. molecular sieve smoke adsorbent, with an inner core diameter of about 50 nanometers and a surface uniformly coated with an IL-PW shell layer with a thickness of 5 nanometers.

[0097] Step four: The polyphenylene sulfide solution was placed in a constant temperature water bath at 70°C to dissolve and form an oil phase solution, and then the ZIF-IL@PW composite powder was dispersed therein. It was transferred to a water bath environment at 25°C to induce phase separation at a rate of 2°C per minute to obtain spherical microcapsule particles, i.e. thermal controlled release microcapsules, with a diameter of about 25 microns, and the mass fraction of the ZIF-IL@PW composite powder encapsulated inside was 65%.

[0098] Step five: ABS resin particles 80 parts and interfacial compatibilizer 10 parts prepared in step three, and thermal controlled release microcapsules 10 parts prepared in step four were placed in a twin-screw extruder, and subjected to segmented temperature control processing:

[0099] The first temperature zone was set to 165°C and 220 rpm to melt and plasticize the ABS resin;

[0100] The second temperature zone was set to 175°C and 220 rpm to dissociate the interfacial compatibilizer, expose the active carboxyl groups, and form an interpenetrating network premix body under the action of screw shear between the melted and plasticized ABS resin and the dissociated interfacial compatibilizer;

[0101] The third temperature zone was set to 185°C and 200 rpm, and the maleic anhydride groups of the interfacial compatibilizer reacted with the polyphenylene sulfide shell on the surface of the thermal controlled release microcapsules to form covalent bond connection between the matrix and the microcapsules.

[0102] The fourth temperature zone was set to 185°C and 220 rpm, and the melt was extruded through the die under constant pressure, then cooled by water-cooled drawbars, and finally cut by a granulator to form uniform beige particles, i.e. flame-retardant ABS particles.

[0103] Comparative Example One:

[0104] Similar to Example One, except that in Step One, the duration of continuous irradiation by the ultraviolet light source was 30 minutes.

[0105] Comparative Example Two:

[0106] Similar to Example One, except that in Step Three, the ZIF-8 nanoparticles and the IL-PW methanol suspension were placed in the microwave reactor at a mass ratio of 1:0.5.

[0107] Comparative Example Three:

[0108] Similar to Example One, except that in Step Four, the rate of temperature reduction to induce phase separation was 0.5°C per minute.

[0109] Comparative Example Four:

[0110] Similar to Example One, except that in Step One, the duration of continuous irradiation by the ultraviolet light source was 120 minutes.

[0111] Comparative Example 5:

[0112] Similar to Example 1, except that the solvothermal self-assembly reaction was carried out at 120 °C in step three.

[0113] Comparative Example 6:

[0114] Similar to Example 1, except that the synthesis of the bromine radical trap in step one was omitted, and the IL-PW methanol suspension in step two was omitted, and the microcapsules directly encapsulated ZIF-8 nanoparticles in step four.

[0115] Comparative Example 7:

[0116] Similar to Example 1, except that the preparation of the thermally controlled microcapsules in step four was omitted, and the ZIF-IL@PW composite powder was directly mixed with ABS resin particles in step five.

[0117] Comparative Example 8:

[0118] Similar to Example 1, except that the temperature was lowered at a rate of 0.1 °C per minute in step four to induce phase separation.

[0119] Comparative Example 9:

[0120] Similar to Example 1, except that the amount of ZIF-8 nanoparticles was halved in step three.

[0121] Comparative Example 10:

[0122] Similar to Example 1, except that the third temperature zone was set to 220 °C in step five.

[0123] The flame-retardant ABS particles prepared in Examples 1-5 and Comparative Examples 1-10 were subjected to ISO 5659-2 smoke density testing and ISO 527 tensile strength standard testing, and the experimental table is shown in Table 1. Figure 2

[0124] The key determinants of smoke suppression performance include radical capture efficiency and molecular sieve adsorption capacity.

[0125] According to Comparative Example 1, insufficient crosslinking results in a loose IL-PW capture network, which leads to an increase in bromine radical escape rate and ultimately an increase in smoke density.

[0126] According to Example 2, the dense crosslinked network has a capture efficiency of 99%, resulting in the lowest smoke density in the entire system.

[0127] According to Comparative Example 2, when the pores are not completely covered, the PAHs interception rate decreases by 50%, which leads to an increase in smoke density.

[0128] ​Example three can be known: 100% channel coverage and IL-PW cooperation, will make the smoke density is 72 (better than the benchmark).

[0129] The synergistic balance of mechanical properties is mainly affected by the amount of interfacial compatibilizer and the protection mechanism of microcapsules.

[0130] According to example five, it can be known that the increase of matrix ratio will make the tensile strength rise to the highest value of 48MPa. But the cost is that the lack of compatibilizer leads to the weakening of the bonding between microcapsules and matrix, and then causes the increase of smoke density.

[0131] According to comparative example seven, it can be known that direct decomposition of ZIF-IL@PW will cause the collapse of tensile strength.

[0132] According to example one, it can be known that PPS layer can block thermal mechanical damage, so that the strength remains at 98%.

[0133] The critical points of process parameter window mainly include cooling rate and matching of extrusion temperature and speed.

[0134] According to comparative example three, it can be known that too slow cooling will lead to uneven microcapsule wall thickness, and then cause the increase of particle size deviation, so that the performance of finished product fluctuates.

[0135] According to example three, it can be known that precise control of phase separation will make the uniformity of 20μm microcapsule rise, and then effectively reduce the dispersion.

[0136] According to comparative example ten, it can be known that high temperature melting PPS shell will cause microcapsule to leak in advance.

[0137] According to example three, it can be known that temperature compensation high shear force can be dispersed with zero damage.

[0138] In summary, the best formula and process parameter combination is in example three:

[0139] Take ABS resin particles 80 parts, interfacial compatibilizer 15 parts and thermal controlled release microcapsule 5 parts;

[0140] Among them, the diameter of the thermal controlled release microcapsule is about 20 microns, and the mass ratio of the ZIF-IL@PW composite powder encapsulated inside is 80%.

[0141] And the best process parameters are:

[0142] The continuous irradiation time of ultraviolet light source in step one is 60 minutes;

[0143] In step three, ZIF-8 nanoparticles and IL-PW methanol suspension are mixed with a mass ratio of 1:1.5;

[0144] In step four, the temperature is reduced at a rate of 3℃ per minute to induce phase separation;

[0145] The third temperature zone in step five is set to 205°C, 250 rpm.

[0146] The SEM microstructure of the flame-retardant ABS particles prepared in Examples 1 to 5 and Comparative Examples 1 to 10 is shown in the following figure: Figure 1 According to the figure, the following conclusions can be drawn:

[0147] In Example 1: The microcapsule structure is complete and uniformly distributed, the shell is tightly combined with the matrix, and the internal flame retardant particles are clearly visible. The surface presents a typical porous honeycomb network, and the concave-convex structure is coherent, indicating that the material has a stable microstructure under standard process.

[0148] In Example 2 (high crosslinking degree): The microcapsule edge is more clear and sharp, and the shell thickness increases. The internal particle distribution density increases, and the fiber-like compatibilizer network in the matrix is visible, and the overall structure is denser than the standard formula.

[0149] In Example 3 (optimal parameters): The most ideal microstructure is shown: the microcapsule size is small and uniform, the internal filling is dense, and the flame retardant particles are highly dispersed. The matrix presents a fine honeycomb network, and the concave-convex transition is natural without visible defects.

[0150] In Example 4 (low temperature process): The microcapsule size is slightly larger but maintains a complete circular shape, and the internal particle distribution is uniform. The surface roughness of the matrix is reduced, and the hole structure is more regular, indicating that the low temperature process is beneficial to maintaining the structural integrity.

[0151] In Example 5 (high matrix ratio): The number of microcapsules decreases but is uniformly distributed, and the matrix ratio increases significantly. The surface concave-convex structure is more gentle, and the hole size decreases, forming a more dense continuous phase network.

[0152] In Comparative Example 1 (UV crosslinking is insufficient): The internal particles of the microcapsule are sparse, and the shell has irregular weak areas. The matrix has abnormal protrusions and depressions, and the surface roughness increases, indicating that insufficient crosslinking leads to a decrease in structural strength.

[0153] In Comparative Example 2 (ZIF loading is insufficient): The internal microcapsule has obvious cavities, and the number of particles is insufficient. The surface of the matrix appears alternating smooth areas and deep grooves, which destroy the original honeycomb continuous structure.

[0154] In Comparative Example 3 (cooling is too slow): The microcapsule size is too large and irregular in shape, and some are fused into groups. The matrix presents an over-expanded foam-like structure, and the hole size is abnormally large, and the surface concave-convex is unbalanced.

[0155] In Comparative Example 4 (UV radiation is excessive): The microcapsule shell is too thick and brittle, and obvious cracks are visible. The internal particles are aggregated into clumps, and the matrix has radial stress cracks, which destroy the structural continuity.

[0156] In Comparative Example 5 (excessive extrusion temperature): the microcapsules are broken in large areas, and the flame retardant particles leak and diffuse. The surface of the matrix has obvious melting traces, and the original honeycomb structure collapses to form irregularly fused agglomerates.

[0157] In Comparative Example 6 (without IL-PW): the microcapsule structure is complete but has internal cavities, and the key flame-retardant component is missing. The surface of the matrix has alternating abnormal dense and loose areas, which destroys the material uniformity.

[0158] In Comparative Example 7 (without encapsulation of ZIF): there is no complete microcapsule structure, and ZIF particles are directly exposed and dispersed. The surface of the matrix is covered with abnormal convex points, forming a discontinuous island structure, and completely losing the honeycomb feature.

[0159] In Comparative Example 8 (too fast cooling): the microcapsules are too small and deformed, and are irregular polygons. The surface of the matrix has a dense network of microcracks, and the concave-convex structure has unnatural jagged edges.

[0160] In Comparative Example 9 (half of ZIF): the microcapsules are obviously empty inside, and the particles are sparsely distributed. The surface of the matrix has abnormally enlarged holes, forming a discontinuous gully structure, which reduces the overall material integrity.

[0161] In Comparative Example 10 (high-temperature extrusion): the microcapsules are completely broken and disappear, and the flame retardant and the matrix are mixed in disorder. The surface has a wave-shaped texture of melting and solidification, and the original microstructure is completely destroyed.

[0162] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions will not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. A flame-retardant ABS plastic raw material, characterized in that, comprising the following components by weight parts: ABS base resin 80 parts, heat-controlled release microcapsule 5 parts, interfacial compatibilizer 15 parts; The heat-controlled release microcapsule contains a bromine radical scavenger and a molecular sieve smoke adsorbent, and the heat-controlled release microcapsule has a polyphenylene sulfide shell; The preparation method comprises the following steps: Step one: phosphotungstic acid and 1-vinyl-3-ethyl imidazole tetrafluoroborate are reacted according to a 3:1 molar ratio at 60°C for 2 hours, and then crosslinked under ultraviolet light for 45-75 minutes to obtain a yellow powder of a bromine radical scavenger; Step two: the product of step one is added to methanol, and 0.1wt% polyvinylpyrrolidone is added as a dispersant to obtain an IL-PW methanol suspension; Step three: ZIF-8 nanoparticles and the product of step two are mixed in methanol at a mass ratio of 1:1.5 and subjected to a solvothermal self-assembly reaction at 100°C to obtain a molecular sieve smoke adsorbent; Step four: the product of step three is encapsulated in a polyphenylene sulfide shell, and a phase separation is induced at a cooling rate of 2-3°C / min to obtain a heat-controlled release microcapsule; Step five: ABS resin, interfacial compatibilizer and heat-controlled release microcapsule are melt blended in a twin-screw extruder, and then extruded and granulated; the melt blending comprises: ABS resin is melt plasticized at a first temperature zone of 165°C and a rotation speed of 220 rpm; An interpenetrating network premix body is formed at a second temperature zone of 175°C and a rotation speed of 220 rpm; A covalent bond between the base and the microcapsule is formed at a third temperature zone of 185-205°C and a rotation speed of 200-250 rpm; Extrusion and granulation are performed at a fourth temperature zone of 185°C and a rotation speed of 220 rpm.

2. The flame-retardant ABS plastic raw material according to claim 1, characterized in that, The heat-controlled release microcapsule has a diameter of 20 microns, and the mass ratio of the ZIF-IL@PW composite powder encapsulated inside is 80%.

3. The flame-retardant ABS plastic raw material according to claim 1, characterized in that, The interfacial compatibilizer is a maleic anhydride modified elastomer.

4. The flame-retardant ABS plastic raw material according to claim 1, characterized in that, The crosslinking time under ultraviolet light in step one is 60 minutes.

5. The flame-retardant ABS plastic raw material according to claim 1, characterized in that, The cooling rate in step four is 3°C / min.

6. The flame-retardant ABS plastic raw material according to claim 1, characterized in that, The temperature in the third temperature zone of step five is 205°C, and the rotation speed is 250 rpm.

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