Composite flame retardant, flame-retardant ABS (Acrylonitrile Butadiene Styrene) composition and preparation method and application thereof

Abstract

The invention discloses a composite flame retardant, a flame-retardant ABS (Acrylonitrile Butadiene Styrene) composition as well as a preparation method and application thereof. The composite flame retardant is prepared from the following raw materials in parts by weight: 30-60 parts of an organic phosphorus chelating agent, 10-25 parts of soluble rare earth inorganic salt and 150-200 parts of zeolite. The preparation method of the composite flame retardant comprises the following steps: A) dispersing zeolite and alkali metal hydroxide in water to form a dispersion liquid I; b) dispersing soluble rare earth inorganic salt in the dispersion liquid I to form dispersion liquid II; and C) adding an organophosphorus chelating agent into the dispersion liquid II, and carrying out a heating reaction at 80-95 DEG C to prepare the composite flame retardant. The composite flame retardant provided by the invention can significantly improve the flame retardance, smoke suppression and mechanical properties of ABS resin.

Description

Technical Field

[0001] The present invention relates to a composite flame retardant, a flame retardant ABS composition, a preparation method thereof and uses thereof. Background Art

[0002] Acrylonitrile-butadiene-styrene (ABS) is a widely used thermoplastic polymer. Compared with many other common polymers, it has advantages such as light weight, good thermal stability, high mechanical properties, good chemical corrosion resistance, etc., and has been widely used in industries such as electronics, automobiles, and aviation. However, a significant limitation of ABS is its inherently high flammability and the generation of a large amount of toxic smoke during combustion. The main current method for flame retardancy of ABS is to improve the flame retardant performance of ABS through the method of halogen-antimony synergy. Although various improvements have been made to the flame retardancy of ABS, due to environmental regulations, the improved ABS materials are still facing restrictions on use, and these improved ABS materials also have the disadvantage of poor smoke suppression performance. Currently, about 95% of the flame retardants used in commercially available ABS materials are halogen-containing flame retardants, especially bromine-containing flame retardants represented by polybrominated diphenyl ethers and polybrominated biphenyls, and they have advantages such as high efficiency, low dosage, small impact on the properties of materials, and moderate price, and their efficiency-price ratio cannot be matched by other flame retardants. However, in recent years, brominated flame retardants have been troubled by environmental problems such as dioxin pollution. In addition, ABS materials using bromine-antimony synergistic flame retardancy will generate a large amount of soot and corrosive gases during thermal cracking and combustion. Currently, the European Union and Japan have successively issued decrees banning the use of such flame retardants. Based on this, those skilled in the art have explored other types of flame retardants for ABS.

[0003] CN102731957A discloses a thermoplastic flame retardant ABS resin composition. The thermoplastic flame retardant ABS resin composition comprises: (A) 100 parts by weight of a matrix resin composed of 10 to 90% by weight of an acrylonitrile-butadiene-styrene copolymer and 90 to 10% by weight of a styrene-acrylonitrile copolymer; (B) 1 to 30 parts by weight of an epoxy resin; and (C) 1 to 30 parts by weight of a phosphorus-based flame retardant. The flame retardant resin composition can provide a thermoplastic resin composition having excellent External Candle Flame Ignition flame retardancy. The flame retardant resin composition can provide excellent external candle flame ignition flame retardancy. However, the flame retardant efficiency of the phosphorus-based flame retardant used is lower than that of the halogen-based flame retardant, so there is a disadvantage that an excessive amount of the phosphorus-based flame retardant needs to be input, and the theoretical coke amount of the phosphorus-based flame retardant system cannot be generated, so there is a disadvantage that the flame retardancy is not easily fully exerted.

[0004] CN114197077A discloses a rare-earth flame-retardant nylon fiber and its preparation method. The raw materials of the rare-earth flame-retardant nylon fiber include the following components in percentage by weight: 91.4 - 98.1% nylon chips, 0.5 - 3% rare-earth-based flame retardant, 0.2 - 2% flame-retardant synergist, 1 - 3% nano-inorganic substance, 0.1 - 0.3% antioxidant, and 0.1 - 0.3% lubricant. The rare-earth-based flame retardant is prepared by a hydrothermal reaction of aminotrimethylphosphonic acid, rare-earth nitrate, deionized water, and lithium chloride. The temperature of this hydrothermal reaction is 150 - 180 °C, and the time is 12 - 24 h. The preparation of this rare-earth-based flame retardant requires the addition of lithium chloride and various filler components. It is extremely easy for various filler components to migrate and cluster in the polymer matrix, resulting in poor compatibility between it and the polymer interface, which is not conducive to the flame-retardant performance and mechanical properties of the rare-earth flame-retardant nylon fiber.

[0005] CN118653222A discloses a flame-retardant polyamide fiber and its preparation method. The flame-retardant polyamide fiber, by mass, the preparation raw materials include: 93.4 - 98.3 parts of polyamide chips, 3 - 4 parts of composite flame retardant, 1 - 2 parts of flame-retardant synergist, 0.1 - 0.3 parts of antioxidant, 8 - 10 parts of modified nano-ceria, and 1 - 2 parts of coupling agent. The composite flame retardant is composed of modified melamine polyphosphate, rare-earth flame retardant, and nano-antimony trioxide modified by silane coupling agent in a mass ratio of 3:5:2 - 3. The preparation method of the rare-earth flame retardant is: adding 3 mol of aminotrimethylphosphonic acid and 1.5 mol of cerium nitrate into a 100 mL hydrothermal reaction kettle, adding 40 mL of deionized water as a solvent, and simultaneously adding 0.15 mol of lithium nitrate, heating and raising the temperature to 150 - 160 °C, and the reaction time is 25 - 30 h to obtain the rare-earth flame retardant. The preparation of this rare-earth flame retardant requires the addition of lithium chloride. It is suitable for the preparation of flame-retardant polyamide fibers. More importantly, this rare-earth flame retardant uses modified nano-antimony trioxide, and the biological toxicity of modified nano-antimony trioxide often limits its application in synergistic flame retardancy.

[0006] CN118005998A discloses a flame-retardant composition, a polyolefin composition, and their preparation methods. The flame-retardant composition includes 2 - 15 parts by weight of ellagic acid-organophosphonic acid-rare-earth ternary complex, 10 - 25 parts by weight of piperazine pyrophosphate, and 2 - 15 parts by weight of guanidine salt flame retardant; wherein, the organophosphonic acid ligand in the ellagic acid-organophosphonic acid-rare-earth ternary complex is selected from one or more of (1-hydroxyethylidene) diphosphonic acid, aminotrimethylphosphonic acid, phytic acid, and hexamethylenediaminetetra(methylene phosphonic acid). In addition to organophosphonic acid, this flame-retardant composition also contains ellagic acid, piperazine pyrophosphate, and guanidine salt flame retardant, and there are more substances added. Although the numerous phosphonic acid compounds involved in this flame-retardant composition can improve the flame-retardant performance of the composite material, the multi-component synergistic flame retardancy often sacrifices the mechanical properties of the composite material and results in a significant increase in production costs. Summary of the Invention

[0007] In view of this, an object of the present invention is to provide a composite flame retardant, which, when used in combination with a small amount of flame retardant synergist, can significantly improve the flame retardancy, smoke suppression and mechanical properties of ABS. Another object of the present invention is to provide a preparation method of the above composite flame retardant. Still another object of the present invention is to provide the use of the above composite flame retardant. Yet another object of the present invention is to provide a flame-retardant ABS composition. Yet another object of the present invention is to provide a preparation method of the above flame-retardant ABS composition.

[0008] The present invention adopts the following technical solutions to achieve the above objects.

[0009] On the one hand, the present invention provides a composite flame retardant, which is made from raw materials including the following parts by weight:

[0010] 30 to 60 parts by weight of an organic phosphorus chelating agent, 10 to 25 parts by weight of a soluble rare earth inorganic salt, and 150 to 200 parts by weight of zeolite.

[0011] According to the composite flame retardant of the present invention, preferably, the organic phosphorus chelating agent is selected from at least one of aminotrimethylphosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, hydroxyethylidene diphosphonic acid, diethylenetriamine pentamethylenephosphonic acid, phytic acid;

[0012] The soluble rare earth inorganic salt is selected from at least one of nitrates, sulfates, phosphates, acetates, halide salts of rare earth elements;

[0013] The rare earth element of the soluble rare earth inorganic salt is selected from at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, ytterbium, lutetium, scandium, yttrium;

[0014] The zeolite is selected from at least one of ZSM-5 zeolite, MCM-22 zeolite, SBA-15 zeolite, Beta zeolite and Y zeolite.

[0015] On the other hand, the present invention also provides a preparation method of the above composite flame retardant, including the following steps:

[0016] A) Dispersing zeolite and alkali metal hydroxide in water to form dispersion liquid I;

[0017] B) Dispersing the soluble rare earth inorganic salt in dispersion liquid I to form dispersion liquid II;

[0018] C) Adding the organic phosphorus chelating agent to dispersion liquid II, and heating and reacting at 80 to 95 °C to obtain the composite flame retardant.

[0019] According to the preparation method of the present invention, preferably:

[0020] In step A), the molar ratio of the zeolite to the alkali metal hydroxide is 1 to 30:1;

[0021] In step B), the molar ratio of the zeolite to the rare earth soluble inorganic salt is 10 to 30:1.

[0022] According to the preparation method of the present invention, preferably, in step C), the heating reaction time is 2 to 15 h.

[0023] On the other hand, the present invention also provides the use of any of the foregoing composite flame retardants in improving the flame retardancy, smoke suppression and mechanical properties of ABS resin.

[0024] On another aspect, the present invention also provides a flame-retardant ABS composition, which is made of raw materials including any of the foregoing composite flame retardants.

[0025] According to the flame-retardant ABS composition of the present invention, preferably, the flame-retardant ABS composition is by weight percentage:

[0026] 8 to 25 wt% of the composite flame retardant, 0.3 to 0.8 wt% of the flame retardant synergist, and the balance is ABS resin.

[0027] According to the flame-retardant ABS composition of the present invention, preferably, the flame retardant synergist is selected from at least one of triphenyl phosphate, bisphenol A-bis(diphenyl phosphate), tert-butylated triphenyl phosphate, and tolyl diphenyl phosphate.

[0028] On another aspect, the present invention also provides a preparation method of the above flame-retardant ABS composition, including the following steps:

[0029] 1) Mix the composite flame retardant and the flame retardant synergist with ABS under stirring, and then carry out melting, kneading and extrusion granulation in an extruder to obtain precursor particles of the flame-retardant ABS composition;

[0030] 2) Carry out flat vulcanization molding on the precursor particles of the flame-retardant ABS composition to obtain the flame-retardant ABS composition.

[0031] The present invention self-assembles a complex formed by an organic phosphorus chelating agent and trivalent rare earth element ions on the surface of zeolite through electrostatic interaction to prepare a composite flame retardant. This composite flame retardant can be uniformly dispersed in ABS resin, improving its interfacial compatibility with ABS; when used together with a small amount of flame retardant synergist, it can significantly improve the flame retardancy, smoke suppression and mechanical properties of ABS. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a TEM image of the composite flame retardant prepared in Preparation Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] <Compound flame retardant>

[0035] The present invention provides a compound flame retardant, which is made from raw materials including the following parts by weight:

[0036] 30-60 parts by weight of an organic phosphorus chelating agent, 10-25 parts by weight of a soluble rare earth inorganic salt, and 150-200 parts by weight of zeolite.

[0037] According to an embodiment of the present invention, the dosage of the organic phosphorus chelating agent can be 30-60 parts by weight, preferably 40-60 parts by weight, and more preferably 40-55 parts by weight.

[0038] According to an embodiment of the present invention, the dosage of the soluble rare earth inorganic salt can be 10-25 parts by weight, preferably 15-25 parts by weight, and more preferably 15-20 parts by weight.

[0039] According to an embodiment of the present invention, the dosage of zeolite can be 150-200 parts by weight, preferably 160-200 parts by weight, and more preferably 160-195 parts by weight.

[0040] According to an embodiment of the present invention, the organic phosphorus chelating agent can be selected from at least one of aminotrimethylphosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, hydroxyethane-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), phytic acid, preferably at least one of aminotrimethylphosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, phytic acid, and more preferably at least one of aminotrimethylphosphonic acid, phytic acid.

[0041] According to an embodiment of the present invention, the soluble rare earth inorganic salt can be selected from at least one of nitrates, sulfates, phosphates, acetates, and halides of rare earth elements, preferably at least one of nitrates, acetates, chlorides, and bromides of rare earth elements, and more preferably at least one of nitrates, chlorides, and bromides of rare earth elements. The soluble rare earth inorganic salt of the present invention can be either a hydrated salt or an anhydrous salt.

[0042] According to an embodiment of the present invention, the rare earth element in the soluble rare earth inorganic salt can be selected from at least one of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), ytterbium (Yb), lutetium (Lu), scandium (Sc), yttrium (Y), preferably at least one of La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Y, and more preferably at least one of La, Ce, Pr, Nd, Sm, Y.

[0043] In the present invention, the zeolite can be any molecular sieve type zeolite well-known in the art, for example but not limited to, at least one selected from ZSM-5 zeolite, MCM-22 zeolite, SBA-15 zeolite, Beta zeolite and Y zeolite, preferably at least one of ZSM-5 zeolite, MCM-22 zeolite and SBA-15 zeolite, and more preferably ZSM-5 zeolite, MCM-22 zeolite or SBA-15 zeolite.

[0044] In the present invention, the zeolite can be of any shape well-known in the art, for example but not limited to, at least one selected from sheet-like, spherical, strip-like and columnar shapes, preferably at least one of sheet-like, spherical and strip-like shapes, and more preferably at least one of sheet-like and spherical shapes.

[0045] The composite flame retardant of the present invention can be uniformly dispersed in the ABS resin, improving its interfacial compatibility with the ABS resin; when used in combination with a flame retardant synergist, it has a synergistic effect, and can significantly improve the flame retardancy, smoke suppression and mechanical properties of the ABS resin.

[0046] <Preparation method of the composite flame retardant>

[0047] The present invention also provides a preparation method of the composite flame retardant as described above, including a zeolite dispersion step, a soluble rare earth inorganic salt dispersion step and a heating reaction step. Preferably, a washing and drying step can also be included. A detailed description is given below.

[0048] Zeolite dispersion step

[0049] Disperse the zeolite and alkali metal hydroxide in water to form dispersion liquid I.

[0050] According to an embodiment of the present invention, the molar ratio of the zeolite to the alkali metal hydroxide can be 1 to 30:1, preferably 5 to 25:1, and more preferably 10 to 20:1.

[0051] In dispersion liquid I, the molar concentration of the alkali metal hydroxide can be 0.2 to 3 mol / L, preferably 0.5 to 2.5 mol / L, and more preferably 0.8 to 2 mol / L.

[0052] According to an embodiment of the present invention, after dispersing the zeolite and the alkali metal hydroxide in water, it can be left standing for a certain time for sufficient alkali etching. The alkali etching time can be 10 to 60 min, preferably 15 to 50 min, and more preferably 20 to 45 min.

[0053] Limiting the molar ratio of zeolite to alkali metal hydroxide and the time of alkali etching within the above ranges is conducive to the full etching of zeolite by alkali metal hydroxide, expanding the pore diameter of zeolite, increasing the probability of rare earth ions entering the pores, and being more conducive to the formation of the composite flame retardant.

[0054] According to one embodiment of the present invention, the alkali metal hydroxide may be selected from at least one of LiOH, NaOH, and KOH, preferably at least one of NaOH and KOH, and more preferably NaOH or KOH.

[0055] In the present invention, the water may be selected from at least one of deionized water and ultrapure water, preferably deionized water or ultrapure water, and more preferably deionized water.

[0056] Soluble rare earth inorganic salt dispersion step

[0057] Disperse the soluble rare earth inorganic salt in the dispersion liquid I to form the dispersion liquid II.

[0058] According to one embodiment of the present invention, the molar ratio of zeolite to the soluble rare earth inorganic salt may be 10 - 30:1, preferably 15 - 30:1, and more preferably 15 - 25:1.

[0059] Limiting the molar ratio of zeolite to the soluble rare earth inorganic salt within the above range is conducive to the trivalent rare earth element ions in the soluble rare earth inorganic salt being adsorbed and anchored in the pores of the zeolite in the dispersion liquid, and is more conducive to the formation of the composite flame retardant.

[0060] According to one embodiment of the present invention, after adding the soluble rare earth inorganic salt to the dispersion liquid I, ultrasonic dispersion can be carried out, and the time of ultrasonic dispersion can be 5 - 20 h, preferably 8 - 18 h, and more preferably 10 - 15 h. A reasonable ultrasonic dispersion time is conducive to the better dispersion of the soluble rare earth inorganic salt in the dispersion liquid I.

[0061] Heating reaction step

[0062] Add the organic phosphorus chelating agent to the dispersion liquid II and heat and react at 80 - 95 °C to obtain the composite flame retardant.

[0063] According to one embodiment of the present invention, the temperature of the heat reaction may be 80 - 95 °C, preferably 80 - 90 °C, and more preferably 85 - 90 °C.

[0064] According to one embodiment of the present invention, the time of the heat reaction may be 2 - 15 h, preferably 3 - 12 h, and more preferably 4 - 10 h.

[0065] In the present invention, the organophosphorus chelating agent can be added directly or formulated into an aqueous solution for addition. It is preferably formulated into an aqueous solution of the organophosphorus chelating agent and added dropwise to Dispersion II for heating reaction. The mass concentration of the aqueous solution of the organophosphorus chelating agent can be 10-80 wt%, preferably 25-75 wt%, and more preferably 30-60 wt%.

[0066] In the present invention, the dropping of the aqueous solution of the organophosphorus chelating agent can be achieved by using any dropping equipment or dropping method well known in the art, and no special limitation is made here. For example but not limited to, a constant pressure dropping funnel can be used to drop the aqueous solution of the organophosphorus chelating agent. The dropping rate can be 1-5 drops / s, preferably 1-3 drops / s, and more preferably 2-3 drops / s. The reaction can be carried out by heating during the dropping of the aqueous solution of the organophosphorus chelating agent. In the present invention, controlling the dropping rate of the aqueous solution of the organophosphorus chelating agent within the above range can ensure that the trivalent rare earth ions anchored on the surface of the zeolite nanosheets undergo sufficient coordination reaction with the organophosphorus chelating agent, ensuring that the rare earth complexes are evenly distributed on the surface of the zeolite nanosheets, which is beneficial to improving the flame retardancy efficiency of the ABS resin.

[0067] In the present invention, stirring can also be carried out during the heating reaction, and the stirring rate can be 800-950 rpm, preferably 850-950 rpm, and more preferably 850-900 rpm.

[0068] Reasonable heating reaction conditions are beneficial to the reaction of the organophosphorus chelating agent with the zeolite adsorbed with trivalent rare earth element ions to generate a composite flame retardant.

[0069] Washing and drying step

[0070] In the present invention, after the heating reaction is completed, the reaction product can be washed and dried to obtain a composite flame retardant.

[0071] In the present invention, the washing detergent can be selected from at least one of water and C1-C5 alkyl alcohols, preferably at least one of water and C1-C3 alkyl alcohols, and more preferably at least one of water, methanol, ethanol, and isopropanol.

[0072] In the present invention, the C1-C5 alkyl alcohols can include but are not limited to methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, sec-pentanol, neopentanol, etc.

[0073] The number of washing times in the present invention can be 1-6 times, preferably 2-5 times, and more preferably 3-5 times. The washing method can be to wash with one detergent or use different detergents in different washing times, and no special limitation is made here.

[0074] Drying can be achieved using any drying method or equipment known in the art, and no special limitation is made here. For example, but not limited to, it can be oven drying or vacuum drying.

[0075] According to an embodiment of the present invention, the drying temperature can be 30 to 100 °C, preferably 40 to 90 °C, more preferably 50 to 85 °C.

[0076] According to an embodiment of the present invention, the drying time can be 6 to 24 h, preferably 10 to 24 h, more preferably 12 to 20 h.

[0077] The water used in the present invention, unless otherwise specified, is selected from at least one of deionized water, ultrapure water, and pure water, preferably deionized water.

[0078] <Use>

[0079] The present invention also provides the use of the above composite flame retardant in improving the flame retardancy, smoke suppression, and mechanical properties of ABS resin.

[0080] According to an embodiment of the present invention, the limiting oxygen index of the flame-retardant ABS composition prepared from the composite flame retardant of the present invention can be at least 21.5%, preferably at least 22%, more preferably at least 22.5%. The peak heat release rate of the prepared flame-retardant ABS composition can be at most 800 kW / m 2 , preferably up to 790 kW / m 2 , more preferably at most 785 kW / m 2 . The total heat release rate of the prepared flame-retardant ABS composition can be at most 110 MJ / m 2 , preferably at most 109 MJ / m 2 , more preferably at most 108 MJ / m 2 . The smoke generation rate of the prepared flame-retardant ABS composition can be at most 0.28 m 2 / s, preferably at most 0.27 m 2 / s, more preferably at most 0.265 m 2 / s.

[0081] According to an embodiment of the present invention, the tensile strength of the flame-retardant ABS composition prepared from the composite flame retardant of the present invention can be at least 44 MPa, preferably at least 44.5 MPa, more preferably at least 45 MPa. The elongation at break of the flame-retardant ABS composition can be at least 17.8%, preferably at least 18%, more preferably at least 18.2%. The flexural strength of the flame-retardant ABS composition can be at least 60.3 MPa, preferably at least 60.4 MPa, more preferably at least 60.5 MPa. The impact strength of the flame-retardant ABS composition can be at least 15.8 kJ / m 2, preferably at least 16 kJ / m 2 , more preferably at least 16.2 kJ / m 2 .

[0082] <Flame Retardant ABS Composition>

[0083] The present invention also provides a flame retardant ABS composition, which is made from raw materials including the aforementioned composite flame retardant.

[0084] According to an embodiment of the present invention, the flame retardant ABS composition by weight percentage is:

[0085] 8 - 25 wt% of the composite flame retardant, 0.3 - 0.8 wt% of the flame retardant synergist, and the balance is ABS resin.

[0086] According to an embodiment of the present invention, based on the total weight of the flame retardant ABS composition, the weight percentage of the composite flame retardant can be 8 - 25 wt%, preferably 10 - 25 wt%, more preferably 10 - 20 wt%. Based on the total weight of the flame retardant ABS composition, the weight percentage of the flame retardant synergist can be 0.3 - 0.8 wt%, preferably 0.5 - 0.8 wt%, more preferably 0.5 - 0.7 wt%.

[0087] According to an embodiment of the present invention, the flame retardant synergist can be selected from at least one of triphenyl phosphate (TPP), bisphenol A - bis(diphenyl phosphate) (BDP), tert - butylated triphenyl phosphate (BPDP), and cresyl diphenyl phosphate (CDP), preferably at least one of TPP, BDP, and BPDP, more preferably one of TPP and BPDP.

[0088] In the present invention, the ABS resin can be any type of ABS resin well - known in the art and is not particularly limited herein. For example, it can be selected from at least one of commercially available acrylonitrile - butadiene - styrene (ABS) copolymers with different grades.

[0089] Limiting the raw material ratio of the flame retardant ABS composition within the above range is beneficial to the uniform dispersion of the composite flame retardant in the ABS resin, improving the compatibility of its interface with the ABS, and more beneficial to the synergistic effect of the composite flame retardant and the flame retardant synergist, significantly improving the flame retardancy, smoke suppression, and mechanical properties of the ABS.

[0090] <Preparation Method of Flame Retardant ABS Composition>

[0091] The present invention also provides a preparation method of the flame retardant ABS composition as described above, including a mixing extrusion granulation step and a flat plate vulcanization molding step. The following is a detailed description.

[0092] Mixing, extrusion and granulation step

[0093] The composite flame retardant and the flame retardant synergist are mixed with the ABS resin under stirring, and then melted, kneaded and extruded into pellets in an extruder to obtain the precursor pellets of the flame-retardant ABS composition.

[0094] In the present invention, melting, kneading and pelletizing can all be achieved in an extruder. The extruder can be any type of extruder well-known in the art and is not particularly limited herein. For example, it can be a twin-screw extruder.

[0095] According to an embodiment of the present invention, the temperatures of each zone of the barrel during extrusion by the extruder are as follows:

[0096] The temperature of the first temperature zone (feeding section) can be 150 - 200 °C, preferably 175 - 200 °C, more preferably 175 - 180 °C. The temperature of the second temperature zone (melting section) can be 160 - 220 °C, preferably 180 - 220 °C, more preferably 180 - 185 °C. The temperature of the third temperature zone (kneading section) can be 180 - 250 °C, preferably 195 - 250 °C, more preferably 195 - 200 °C. The temperature of the die head can be 190 - 220 °C, preferably 198 - 220 °C, more preferably 198 - 203 °C. The main machine speed can be 20 - 50 rpm, preferably 25 - 40 rpm, more preferably 30 - 35 rpm, and the auxiliary machine speed can be 15 - 40 rpm, preferably 20 - 35 rpm, more preferably 25 - 30 rpm.

[0097] Limiting the conditions of melting, kneading and pelletizing within the above ranges is beneficial to the uniform melting and plasticization of the mixed materials and improves the quality and strength of the precursor pellets of the flame-retardant ABS composition.

[0098] In the present invention, stirring can be achieved using any type of stirring equipment well-known in the art and is not particularly limited herein. For example, but not limited to, a vertical mixer, a submersible mixer or a particle mixer. The stirring rate can be 500 - 1500 rpm, preferably 700 - 1300 rpm, more preferably 1000 - 1200 rpm.

[0099] Flat vulcanization molding step

[0100] The precursor pellets of the flame-retardant ABS composition are subjected to flat vulcanization molding to obtain the flame-retardant ABS composition.

[0101] The flat vulcanization molding of the present invention can be achieved using a flat vulcanizer. The flat vulcanizer can be any type well-known in the art and is not particularly limited herein. According to a specific embodiment of the present invention, the flat vulcanizer can be a double-layer flat vulcanizer with a hot pressing layer and a cold pressing layer. Both the hot pressing layer and the cold pressing layer have an upper cavity plate and a lower cavity plate. The flat vulcanizer can provide pressure.

[0102] According to an embodiment of the present invention, during hot pressing, the temperatures of the upper cavity plate and the lower cavity plate of the hot pressing layer of the flat vulcanizing machine are as follows:

[0103] The temperature of the upper cavity plate of the hot pressing layer can be 190 - 220 °C, preferably 195 - 220 °C, and more preferably 195 - 200 °C.

[0104] The temperature of the lower cavity plate of the hot pressing layer can be 190 - 220 °C, preferably 195 - 220 °C, and more preferably 195 - 200 °C.

[0105] According to an embodiment of the present invention, after hot pressing is completed, the hot pressing layer of the flat vulcanizing machine is switched to a cold pressing layer, and the upper cavity plate and the lower cavity plate of the cold pressing layer are cold pressed using the self-softness of the flame-retardant ABS composition precursor particles.

[0106] According to an embodiment of the present invention, the hydraulic pressure of the flat vulcanizing machine can be 10 - 20 MPa, preferably 10 - 18 MPa, and more preferably 12 - 18 MPa.

[0107] According to an embodiment of the present invention, during flat vulcanization molding, it includes a hot pressing pre-pressing stage, a hot pressing pressurizing stage, a cold pressing pre-pressing stage, and a cold pressing pressurizing stage. The time for each stage is as follows:

[0108] The time for the hot pressing pre-pressing stage can be 1 - 10 min, preferably 2 - 8 min, and more preferably 3 - 5 min. The time for the hot pressing pressurizing stage can be 1 - 15 min, preferably 3 - 10 min, and more preferably 5 - 8 min. The time for the cold pressing pre-pressing stage can be 1 - 10 min, preferably 2 - 8 min, and more preferably 3 - 5 min. The time for the cold pressing pressurizing stage can be 1 - 12 min, preferably 2 - 10 min, and more preferably 3 - 5 min.

[0109] Reasonable flat vulcanization molding conditions are beneficial to improving the flame retardancy, smoke suppression, and mechanical properties of the flame-retardant ABS composition.

[0110] <Testing method>

[0111] TEM measurement: Conducted using a Thermo Fisher Talos F200i transmission electron microscope.

[0112] Limiting oxygen index (LOI) test

[0113] Determination is carried out according to the content of Part 1 and Part 2 in GB / T2406.1 - 2008. The experimental instrument is a limiting oxygen index tester, purchased from GOTVIL SCIENTIFIC INSTRUMENTS (QINGDAO) CO., LTD. The specimen size is 130×6.5×3 mm 3 , and the experiment is repeated 3 times and the average value is taken.

[0114] UL-94 vertical burning rating test

[0115] The measurement is carried out according to ISO-1210. The experimental instrument is a horizontal and vertical burning tester, purchased from GOTVIL SCIENTIFIC INSTRUMENTS (QINGDAO) CO., LTD. The specimen size is 130×13×3mm 3 , and the experiment is repeated 3 times and the average value is taken.

[0116] Cone calorimetry test

[0117] The flame retardancy and smoke suppression performance of the ABS composite material are measured by an FTT mini cone calorimeter, in accordance with ISO5660-1. The heat flux density is 35kW / m 2 , and the size of the specimen: 100×100×3mm 3 , and the experiment is repeated 3 times and the average value is taken.

[0118] Mechanical property test

[0119] The measurement is carried out by a universal testing machine with reference to ASTM D-638. The universal testing machine is a high-speed universal testing machine, and the selected tensile rate is 100mm / min. The specimen is dumbbell-shaped, and the narrow cross-section of the specimen is 33×6×3.2mm 3 . All specimens are repeatedly tested 7 times and the average value is taken.

[0120] <Raw material description>

[0121] Unless otherwise specified, the raw materials in the following examples are all commercially available products.

[0122] Among them, zeolite ZSM-5 is purchased from Tianjin Xiensi Reagent Co., Ltd., with a molecular weight of 162.05 and a silicon-aluminum ratio of 20-30.

[0123] The grade of the ABS resin is DG-417 and is purchased from Tianjin Dagu Chemical Co., Ltd.

[0124] BPDP is for industrial mass production level and is purchased from Wuhan Kamik Technology Co., Ltd.

[0125] The flat vulcanizer is an XH-406C electric flat vulcanizer, purchased from Dongguan Xihua Testing Instruments Co., Ltd.

[0126] Preparation Examples 1-4

[0127] Prepare the composite flame retardant with reference to the parameters in Table 1:

[0128] A) Disperse a certain weight of flaky ZSM-5 zeolite and a certain weight of NaOH in 60 mL of deionized water, and perform alkali etching for 30 min to form dispersion liquid I.

[0129] B) adding a soluble rare earth inorganic salt to dispersion I and ultrasonically dispersing it for 12 hours to form dispersion II; in dispersion II, the trivalent rare earth element ions (denoted as RE(III)) of the soluble rare earth inorganic salt are adsorbed and anchored in the pores of the ZSM-5 nanosheets at room temperature.

[0130] C) using a constant pressure dropping funnel, an aqueous solution of aminotrimethylenephosphonic acid (ATMP) (mass concentration of 50 wt%) was added to the dispersion II at a dropping rate of 2 drops / s, while stirring at a speed of 880 rpm and heating for coordination reaction to obtain a composite flame retardant.

[0131] D) The composite flame retardant was washed with deionized water, methanol and ethanol in sequence for a total of 4 times (one wash with deionized water, methanol and ethanol in sequence was counted as one time), and then vacuum dried for 15 hours.

[0132] Table 1

[0133]

[0134]

[0135] Examples 1-3 and Comparative Examples 1-2

[0136] Using the composite flame retardant (ZSM@ATMP-Ce) prepared in Preparation Example 1, 100 g of flame retardant ABS composition was prepared with reference to the parameters in Table 2, wherein the flame retardant synergist was tert-butylated triphenyl phosphate (BPDP):

[0137] 1) A certain mass of composite flame retardant and flame retardant synergist is fully mixed with ABS under stirring at 1200 rpm, and melted, mixed, extruded and granulated by a twin-screw extruder to obtain flame retardant ABS composition precursor particles.

[0138] Melting, mixing and extrusion granulation are all completed in the extruder. The temperature of each zone of the screw barrel during extrusion is as follows:

[0139] The temperature of the first temperature zone (transporting section) is 175°C; the temperature of the second temperature zone (melting section) is 185°C; and the temperature of the third temperature zone (mixing section) is 195°C.

[0140] The head temperature of the extruder during extrusion was 203°C; the main engine speed was 35 rpm, and the auxiliary engine speed was 25 rpm.

[0141] 2) vulcanizing the flame retardant ABS composition precursor particles to obtain a flame retardant ABS composition; wherein:

[0142] The flat vulcanization molding is carried out in a flat vulcanizing machine, which has a hot pressing layer and a cold pressing layer. The hot pressing layer has an upper cavity plate and a lower cavity plate. During hot pressing, the temperatures of the upper cavity plate and the lower cavity plate of the hot pressing layer are 195 °C respectively, and the hydraulic pressure of the flat vulcanizing machine is 15 MPa.

[0143] After the hot pressing is completed, the hot pressing layer of the flat vulcanizing machine is switched to the cold pressing layer, and cold pressing is carried out by using the self-softness of the precursor particles of the flame-retardant ABS composition.

[0144] During the flat vulcanization molding, it includes a hot pressing pre-pressing stage, a hot pressing pressurizing stage, a cold pressing pre-pressing stage and a cold pressing pressurizing stage. The time of each stage is as follows:

[0145] The time of the hot pressing pre-pressing stage is 3 min. The time of the hot pressing pressurizing stage is 5 min. The time of the cold pressing pre-pressing stage is 3 min. The time of the cold pressing pressurizing stage is 5 min.

[0146] Table 2

[0147]

[0148] Experimental Example 1

[0149] The composite flame retardant prepared in Preparation Example 1 was detected by TEM (transmission electron microscope), and the results are as Figure 1 shown.

[0150] It can be seen from Figure 1 that in the composite flame retardant, the complex formed by ATMP and Ce 3+ self-assembles on the surface of ZSM-5 zeolite through electrostatic interaction to form a stable composite structure. The Ce 3+ is anchored in the pore channels of the zeolite nanosheets after alkali etching, and ATMP acts as a chelating agent. The negatively charged phosphate groups on it react with Ce 3+ to form a complex and are uniformly deposited on the surface of the nanosheets.

[0151] The flame-retardant ABS compositions prepared in Examples 1 to 3, the pure ABS resin in Comparative Example 1 were respectively subjected to limiting oxygen index (LOI) test, UL-94 vertical burning rating test, cone calorimetry test and mechanical property test. The test results are shown in Tables 3 and 4.

[0152] Table 3 Test results of flame retardancy and smoke suppression performance

[0153]

[0154] Note: "No Rating" indicates that the flame retardant performance of the tested material is poor, and its vertical burning rating cannot reach the lowest grade V-2.

[0155] As can be seen from Table 3, the flame retardant properties of the flame retardant ABS compositions prepared in the examples are significantly better than those of the flame retardant ABS compositions prepared in Comparative Example 2 and the pure ABS resin in Comparative Example 1.

[0156] Table 4 Mechanical Property Test Results

[0157]

[0158] As can be seen from Table 4, the mechanical properties of the flame retardant ABS compositions prepared in the examples, especially the tensile strength and impact strength, are significantly better than those of the flame retardant ABS compositions and pure ABS resin prepared in the comparative examples.

[0159] The present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any variations, improvements, and substitutions that can be conceived by those skilled in the art fall within the scope of the present invention.

Claims

1. A composite flame retardant, characterized in that, The composite flame retardant is prepared from the following raw materials in parts by weight: 30 - 60 parts by weight of an organic phosphorus chelating agent, 10 - 25 parts by weight of a soluble rare earth inorganic salt, and 150 - 200 parts by weight of zeolite.

2. The composite flame retardant according to claim 1, wherein: The organic phosphorus chelating agent is selected from at least one of amino trimethylene phosphonic acid, hexamethylenediamine tetra(methylene phosphonic acid), hydroxyethylidene diphosphonic acid, diethylenetriamine penta(methylene phosphonic acid), and phytic acid; The soluble rare earth inorganic salt is selected from at least one of nitrates, sulfates, phosphates, acetates, and halides of rare earth elements; The rare earth element of the soluble rare earth inorganic salt is selected from at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, ytterbium, lutetium, scandium, and yttrium; The zeolite is selected from at least one of ZSM-5 zeolite, MCM-22 zeolite, SBA-15 zeolite, Beta zeolite, and Y zeolite.

3. A method for preparing the composite flame retardant according to claim 1 or 2, comprising the following steps: A) Dispersing zeolite and alkali metal hydroxide in water to form dispersion liquid I; B) Dispersing the soluble rare earth inorganic salt in dispersion liquid I to form dispersion liquid II; C) Adding the organic phosphorus chelating agent to dispersion liquid II, and heating and reacting at 80 - 95 °C to obtain the composite flame retardant.

4. The preparation method according to claim 3, wherein: In step A), the molar ratio of the zeolite to the alkali metal hydroxide is 1 - 30:1; In step B), the molar ratio of the zeolite to the rare earth soluble inorganic salt is 10 - 30:

1.

5. The preparation method according to claim 3, characterized in that, In step C), the heating reaction time is 2 - 15 h.

6. Use of the composite flame retardant according to claim 1 or 2 in improving the flame retardancy, smoke suppression, and mechanical properties of ABS resin.

7. A flame-retardant ABS composition, characterized in that, The flame-retardant ABS composition is prepared from the raw materials including the composite flame retardant according to claim 1 or 2.

8. The flame retardant ABS composition according to claim 7, wherein, The flame-retardant ABS composition is by weight percentage: 8 - 25 wt% of the composite flame retardant, 0.3 - 0.8 wt% of a flame retardant synergist, and the balance is ABS resin.

9. The flame-retardant ABS composition according to claim 8, wherein The flame retardant synergist is selected from at least one of triphenyl phosphate, bisphenol A-bis(diphenyl phosphate), tert-butylated triphenyl phosphate, and tolyl diphenyl phosphate.

10. A method for preparing the flame-retardant ABS composition according to claim 8 or 9, comprising the following steps: 1) Mixing the composite flame retardant and the flame retardant synergist with the ABS resin under stirring, and then performing melting, kneading, and extrusion granulation in an extruder to obtain precursor particles of the flame-retardant ABS composition; 2) Performing flat vulcanization molding on the precursor particles of the flame-retardant ABS composition to obtain the flame-retardant ABS composition.

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