Composite flame retardant, composite flame retardant masterbatch and manufacturing method thereof

Abstract

The present invention provides a composite flame retardant, a composite flame retardant masterbatch, and a method for producing the same, which are characterized by excellent flame retardancy and relatively low cost, and which can be suitably applied to flame-retardant polymer material products, by blending a relatively low content of antimony salt with a specific phosphate, thereby reducing dependency on antimony resources. [Solution] The composite flame retardant of the present invention contains, by weight percentage, 15% to 65% of an antimony salt and 35% to 85% of a phosphate salt including one or more of strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite.

Description

[Technical Field]

[0001] The present invention relates to the technical field of flame retardants, and more particularly to a composite flame retardant, a composite flame retardant masterbatch and a method for preparing the same. [Background technology]

[0002] The rapid development of modern information technology has promoted the development of high molecular weight polymer materials, and currently, polymer-based materials are widely used in various fields such as automobile interiors, household appliances, etc. However, most common polymer materials, such as polyvinyl chloride, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, and ABS resin, are flammable or combustible materials, and when such polymer material products burn, they are prone to fire, potentially threatening the safety of people's lives and property.

[0003] Flame retardants, also known as fire-resistant or fire-retardant agents, are an important additive in synthetic polymer materials, providing them with flame retardancy, self-extinguishing, and smoke-suppressing properties. They primarily include phosphorus-, nitrogen-, silicon-, halogen-, foam-forming, and inorganic fillers. Antimony-containing flame retardants are the most widely used, increasing the thermal decomposition temperature of materials to make them less susceptible to high-temperature combustion. They also absorb the heat released during combustion to generate non-flammable gases such as carbon dioxide and water vapor, thereby diluting flammable gases and slowing the burning rate of materials.

[0004] Antimony-containing flame retardants generally work synergistically with halogen-based flame retardants to achieve high effectiveness. However, halogen-based flame retardants contain halogen atoms, which release large amounts of smoke and toxic and corrosive harmful gases when burned, and 80% of fatalities that occur during fires are caused by suffocation from the smoke and harmful gases.

[0005] To reduce the generation of harmful gases, some companies use flame retardant color cakes with a high antimony content (≥80%). However, too high an antimony content requires higher dispersibility, which leaves the remaining 20% ​​of the formulation filled with auxiliary materials required for processing, such as resins and plasticizers, leaving no room for other flame retardant synergists, limiting the flame retardant effect of the flame retardant color cake. Meanwhile, antimony is a rare metal, and the price of antimony resources has risen sharply in recent years. Therefore, flame retardants with a high antimony content significantly increase the production costs of flame-retardant polymer materials. Summary of the Invention

[0006] In order to solve at least one of the above problems, the present invention provides a composite flame retardant, a composite flame retardant masterbatch, and a manufacturing method thereof. The composite flame retardant is a mixture of a relatively low content of antimony salt and a specific phosphate salt, thereby reducing dependence on antimony resources, and has the characteristics of excellent flame retardancy and relatively low cost, making it suitable for use in flame-retardant polymer material products.

[0007] In a first aspect, the composite flame retardant of the present invention comprises, by weight percentage, 15% to 65% of an antimony salt and 35% to 85% of a phosphate salt including one or more of strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite.

[0008] Preferably, the antimony salt comprises one or more of antimony trioxide, antimony pentoxide, and sodium antimonate.

[0009] Preferably, the phosphate contains, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 90% strontium phosphate, and 0% to 90% hypophosphorous acid.

[0010] Preferably, the phosphate comprises, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 80% strontium phosphate, 0% to 80% aluminum hypophosphite, and 10% to 90% melamine polyphosphate.

[0011] Preferably, the phosphate salt contains, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 80% strontium phosphate, 0% to 80% aluminum hypophosphite, and 10% to 90% ammonium polyphosphate.

[0012] Preferably, the phosphate comprises, by weight percentage, 10% to 80% strontium hydrogen phosphate, 0% to 70% strontium phosphate, 0% to 70% aluminum hypophosphite, 10% to 80% melamine polyphosphate, and 10% to 80% ammonium polyphosphate.

[0013] The combustion of most polymers can be divided into three main stages: 1) the polymer decomposes combustible gases under the action of a heat source; 2) the combustible gases reach a certain concentration, mix with the surrounding air, and burn, releasing heat; and 3) the released heat is returned to the polymer, continuing to heat it, further promoting the decomposition of the polymer and forming a thermal cycle that expands the combustion.

[0014] Based on the above combustion mechanism, the present invention uses a low-antimony compound containing a required amount of antimony salt, retaining the flame retardant mechanism of its vapor-phase coating, i.e., lowering the combustion temperature through an internal endothermic reaction, and vaporizing after combustion to form a protective film that blocks air, diluting the oxygen concentration in the air, creating a "suffocation" effect, thereby achieving flame retardancy. However, in the case of flame retardancy due to oxygen deficiency, a large amount of combustible substances remain in the material itself, leading to continued burning, residual combustion, and smoldering in a low-oxygen environment.

[0015] Therefore, the compounding components of the present invention are compounded with appropriate amounts of specific phosphates and antimony salts, among which strontium hydrogen phosphate and strontium phosphate are usually used as fluorescent analytical reagents and play a fundamental role in chemical detection. However, in the course of research into the present invention, it was discovered that these two substances, like aluminum hypophosphite, can also be used as inorganic flame retardants, and the effect of antimony salts compounded with the above phosphates is significantly better than that of other phosphates.

[0016] This may be due to the fact that strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite all contain phosphorus (P) and oxygen (O). When exposed to heat, strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite decompose to generate water vapor, which absorbs heat and reduces the ambient temperature. After decomposition, they form a molten phosphate that coats the surface of combustible materials, blocking oxygen and combustible materials. Furthermore, the antimony salts exert a synergistic dual flame retardant effect of absorbing heat and releasing gas. At the same time, phosphorus oxide can capture free radicals (e.g., H, OH) generated during the combustion process, suppressing the combustion chain reaction. Furthermore, the combustion of combustible materials is itself a carbon oxidation process, with an equal number of carbon atoms being oxidized to CO2 and the amount of heat generated being approximately four times that of the oxidation of carbon to CO. Therefore, promoting the oxidation of carbon to CO and suppressing the oxidation of carbon to CO2 reduces the amount of heat generated and the thermal cycle of combustion. Phosphorus in the low-antimony compound is decomposed by heat to produce phosphoric acid, which promotes the oxidation of carbon to CO (P2O5 + 5C → 2P + 5CO), and also reduces the temperature of the burning material and extinguishes the fire.

[0017] Furthermore, strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite can be uniformly dispersed in polymer substrates (e.g., polyvinyl chloride, polyethylene, polypropylene, and epoxy resins) by direct mechanical mixing or melt extrusion, with little aggregation or phase separation, and only a 5%-10% impact on material mechanical properties (e.g., tensile strength and impact toughness) (far lower than the 20%-30% impact of other inorganic flame retardants, e.g., aluminum hydroxide). Furthermore, the decomposition onset temperatures of these three phosphates are higher than the processing temperatures of many polymers, making them less susceptible to premature decomposition during high-temperature processing such as extrusion and injection molding, ensuring the stability of the manufacturing process and flame retardant performance.

[0018] In the present invention, strontium hydrogen phosphate and strontium phosphate have better flame retardancy than aluminum hypophosphite, which may be due to the fact that the phosphorus-strontium contained in both materials can produce a synergistic flame retardant effect. That is, when strontium hydrogen phosphate and strontium phosphate are decomposed by heat, they release phosphorus-containing active materials such as phosphoric acid and metaphosphoric acid, forming a viscous molten glass-like carbon layer on the surface of the material, which blocks the transfer of oxygen and heat and suppresses the release of flammable gases. At the same time, the strontium ions (Sr 2+ ) bonds with groups such as hydroxyl groups and carboxyl groups in the carbon layer, strengthening the high-temperature resistance and density of the carbon layer and preventing the carbon layer from cracking or decomposing at high temperatures, thereby improving the durability of the flame retardancy. Compared with a single phosphorus-based flame retardant (e.g., ammonium phosphate), strontium hydrogen phosphate can improve the retention rate of the carbon layer formed on the polymer by 15% to 20% and the limiting oxygen index (LOI) by 5 to 8 units. Strontium phosphate can also improve the retention rate of the carbon layer and the limiting oxygen index to some extent, so a composite flame retardant containing strontium hydrogen phosphate and / or strontium phosphate is more preferred.

[0019] Based on this, the present invention can reduce the content of antimony salt in the composite flame retardant to 65% or less, thereby reducing the amount of antimony resource added and thereby reducing costs.The composite flame retardant of the present invention not only effectively reduces the content of antimony salt and achieves the effect of blending antimony salt with a halogen flame retardant, but also solves the dispersibility problem caused by reducing the high antimony content, and has excellent flame retardancy and processing stability.

[0020] One or more of the strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite are more preferably blended with melamine polyphosphate (hereinafter referred to as MPP) and ammonium polyphosphate (hereinafter referred to as APP). This is based on the fact that the phosphates form a protective film of metaphosphate, polymetaphosphate, and pyrophosphate after being decomposed by heat, and the nitrogen forms a pyrophosphate and nitrogen-phosphorus foam insulation layer after being heated, which blocks oxygen and further strengthens the gas-phase coating method of antimony salts. On the other hand, metaphosphate and polymetaphosphate are strong dehydrating agents that promote the dehydration of organic matter in the combustion material, consume a large amount of heat through the vaporization of water, and accelerate the carbonization reaction to consume combustible materials, forming a foam paste with a difficult-to-burn coked carbon structure, which creates a coating effect and interrupts the combustion chain reaction. This belongs to the solid-phase coating method, and the gas-phase and solid-phase methods combine to form a foam carbon layer through the synergistic effect of "phosphorus-nitrogen-carbon," resulting in better flame retardancy.

[0021] In a second aspect, the composite flame-retardant masterbatch according to the present invention comprises, by weight percentage, 20% to 95% of the composite flame retardant according to any one of claims 1 to 4, 0% to 16% of a polymer base material, and 5% to 64% of a processing aid.

[0022] Preferably, the polymer substrate is one or more of an olefin-based polymer, an ester-based polymer, an ethylene-based polymer, a styrene-based polymer, and a polyurethane.

[0023] According to the above technical means, flame-retardant masterbatches are concentrates produced by dispersing a high concentration of flame retardant in a carrier resin through a special process. Such concentrates typically appear in cake or granular forms. The polymer substrate can be tailored to meet different needs. For example, in the case of a flame-retardant polymer material for PVC artificial leather, the polymer substrate in the composite flame-retardant masterbatch used can be PVC. An appropriate amount of plasticizer needs to be added to the additive to improve the moldability of the masterbatch. Alternatively, the polymer substrate can be tailored to a material that is highly compatible with PVC, such as EVA. Processing aids, mainly including dispersants, stabilizers, and lubricants, are used to improve the dispersion and processing performance of the flame retardant. Compared with adding conventional flame retardants, preparing a flame retardant masterbatch improves the dispersibility of the flame retardant in the resin, reduces the amount of flame retardant added, reduces the difficulty and cost of processing, and reduces the impact of adding the flame retardant on the mechanical properties of the resin. After adding, defects such as layer splitting, patterns, and precipitation are less likely to occur, improving the working environment and saving manpower, material costs, time, etc.

[0024] In a third aspect, the method for producing the composite flame-retardant masterbatch according to the present invention includes the steps of weighing and premixing each component according to the formulation of the composite flame-retardant masterbatch, introducing the obtained premix into an internal mixer and mixing uniformly, grinding and dispersing the mixture, and then press-molding and cutting the mixture to obtain a cake-like structure of the composite flame-retardant masterbatch.

[0025] In a fourth aspect, the method for producing a composite flame-retardant masterbatch according to the present invention includes the steps of weighing and premixing each component according to the formulation of the composite flame-retardant masterbatch, and feeding the obtained premix into a screw extruder for extrusion granulation to obtain a composite flame-retardant masterbatch with a granular structure.

[0026] According to the above technical means, the flame retardant of the present invention can not only be directly applied in the form of mixed powder, but also be prepared in a cake-like structure or granular structure according to different needs. In contrast to the mixed powder form, the cake-like structure and granular structure composite flame retardant masterbatch can contain other processing aids, which is convenient for the transportation and storage of the composite flame retardant and its subsequent application in flame-retardant polymer material products.

[0027] From the above, the present invention has the following beneficial effects.

[0028] 1. The composite flame retardant of the present invention uses low-antimony compounding components to reduce the antimony salt content to 65% or less, thereby reducing dependence on antimony resources. Furthermore, the compounding components also have space for adding other flame retardants, such as one or more of strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite. The combination of multiple flame retardant mechanisms, including gas-phase coating, solid-phase coating, endothermic cooling, and free radical scavenging, provides excellent flame retardancy, low cost, high processing stability, and easy uniform dispersion in polymer materials, making it suitable for use in flame-retardant polymer material products.

[0029] 2. In the composite flame retardant of the present invention, a phosphate containing one or more of strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite combined with MPP and APP is more preferred. The phosphate contains nitrogen and phosphorus, and forms a nitrogen-phosphorus foam insulation layer to block oxygen after combustion and heat exposure, and promotes the dehydration and heat absorption of organic matter in the combustion material, thereby providing better flame retardant effect.

[0030] 3. The composite flame retardant of the present invention can be directly added or prepared into a composite flame retardant masterbatch in a specific form such as cake or granules, so as to facilitate storage, transportation, and subsequent rapid dispersion in the flame retardant polymer material. The composite flame retardant in the composite flame retardant masterbatch can be uniformly dispersed by mechanical mixing or melt extrusion, which makes the preparation of the composite flame retardant masterbatch easier and has better application prospects. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic diagram of a combustion performance sample of the present invention. [Figure 2] FIG. 10 is a sample diagram of the (1) group of samples corresponding to Example 38 of the present invention after combustion. [Figure 3] FIG. 10 is a sample diagram of the (1) group of samples corresponding to Example 42 of the present invention after combustion. [Figure 4] FIG. 10 is a sample diagram of the (1) group of samples corresponding to Example 43 of the present invention after combustion. [Figure 5] FIG. 10 is a sample diagram of the (1) group of samples corresponding to Example 44 of the present invention after combustion. DETAILED DESCRIPTION OF THE INVENTION

[0032] In order to make the above-mentioned objects, features, and advantages of the present invention more clear, specific embodiments of the present invention will be described in detail below. In order to fully understand the present invention, many specific details will be described in the following description. However, the present invention can be implemented in many ways other than those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention, so the present invention is not limited to the specific examples disclosed below.

[0033] The composite flame retardant and composite flame retardant masterbatch of the present invention can be applied to many industries such as military, space, transportation, power and civilian, including but not limited to flame retardant modification of materials such as PVC, EVA, PE, ABS resin, PP, PET, etc.

[0034] The composite flame retardant according to the present invention comprises, by weight percentage, 15% to 65% of antimony salt and 35% to 85% of phosphate, and a method for producing the composite flame retardant includes the steps of weighing each component as needed, adding the components to a mixer, and stirring the components uniformly at a rotation speed of 1000 r / min to 3000 r / min.

[0035] Antimony salts include one or more of antimony trioxide, antimony pentoxide, and sodium antimonate. Phosphate salts include one or more of strontium hydrogen phosphate, strontium phosphate, and aluminum hypophosphite.

[0036] The product produced after burning and decomposing the phosphate salt exhibits a synergistic effect with the antimony salt, realizing a combination of multiple flame retardant mechanisms including gas-phase coating, solid-phase coating, endothermic cooling, and free radical scavenging, which effectively reduces the content of antimony salt and ensures that the composite flame retardant has high flame retardant performance.

[0037] In some embodiments of the present invention, the phosphate further comprises melamine polyphosphate (MPP), and more preferably, the weight ratio of strontium hydrogen phosphate, strontium phosphate, aluminum hypophosphite to melamine polyphosphate is 10-90:0-80:0-80:10-90. MPP is a gas source component in intumescent flame retardant systems (IFRs), and decomposes upon exposure to heat to release nitrogen gas, contributing to the formation of an expanded carbon layer.

[0038] In another embodiment of the present invention, the phosphate further comprises ammonium polyphosphate (APP), more preferably in a weight ratio of strontium hydrogen phosphate, strontium phosphate, aluminum hypophosphite, or melamine polyphosphate to ammonium polyphosphate of 10-80:0-70:0-70:10-80:10-80. APP serves as an acid source and gas source in intumescent flame retardant (IFR) systems. When heated, it releases acidic substances such as polymetaphosphoric acid to promote char formation and gases such as ammonia gas to retard combustion. The nitrogen and phosphorus elements contained in the APP further enhance the flame retardant effect.

[0039] Research has shown that when strontium hydrogen phosphate is used alone, its flame retardant efficiency is relatively low, but when it is blended with MPP and APP, a foamed carbon layer is formed due to the synergistic effect of "phosphorus-nitrogen-carbon", which effectively improves the flame retardant effect. Therefore, the present invention has found that it is more preferable to use a blend of strontium hydrogen phosphate, MPP and APP.

[0040] The composite flame retardant masterbatch of the present invention comprises, by weight percentage, 20% to 95% of the composite flame retardant disclosed above, 0% to 16% of the polymer base material, and 5% to 64% of the processing aid.

[0041] The polymer substrate used in the composite flame-retardant masterbatch must have good compatibility with the flame-retardant polymer material product to which it is applied. Specifically, the polymer substrate can be selected according to the properties of the flame-retardant polymer material product, and preferably may be one or more of olefin-based polymers, ester-based polymers, ethylene-based polymers, styrene-based polymers, and polyurethane (PU).

[0042] In some embodiments of the present invention, olefin-based polymers include polyethylene (PE), polypropylene (PP), etc.; ester-based polymers include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), etc.; ethylene-based polymers include polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer (EVA), etc.; and styrene-based polymers include polystyrene (PS), styrene-acrylonitrile resin (SAN), styrene-butadiene-acrylonitrile resin (ABS), etc.

[0043] The auxiliary agents used in the composite flame-retardant masterbatch of the present invention can be increased or decreased depending on the properties of the polymer substrate, and include one or more of plasticizers, dispersants, stabilizers, and lubricants.

[0044] Depending on the properties of the polymer substrate, the plasticizer may be one or more selected from pyromellitic ester-based plasticizers, trimellitic ester-based plasticizers, phthalic ester-based plasticizers, terephthalic ester-based plasticizers, isophthalic ester-based plasticizers, phosphate ester-based plasticizers, and epoxidized vegetable oils. The dispersant is preferably calcium carbonate, the stabilizer is preferably a calcium zinc stabilizer and an organotin stabilizer, and the lubricant includes one or more of metal soap-based lubricants, hydrocarbon-based lubricants, fatty acid-based lubricants, and fatty acid ester-based lubricants. In some embodiments of the present invention, the auxiliary further includes a series of substances that can improve or impart specific performance to the polymer, such as colorants and antistatic agents.

[0045] The composite flame-retardant masterbatch of the present invention can be prepared in a manner that meets the needs of downstream companies, and preferably has one of a color cake structure and a granular structure.

[0046] The first method for preparing a flame-retardant masterbatch with a color cake structure involves weighing and premixing the components according to the composition of the composite flame-retardant masterbatch, then introducing the resulting premix into an internal mixer, mixing uniformly, grinding, dispersing, and then pressing and cutting to obtain a cake-shaped composite flame-retardant masterbatch. The processing parameters for these steps need to be adjusted according to the characteristics of different polymer substrates. For example, in the case of PVC color cake, the premix is ​​introduced into an internal mixer (or kneader) to melt the PVC resin through mechanical shear heating, while the other components are further dispersed in the molten resin under shear force to achieve uniform bonding between the components and the carrier. The premix is ​​then rolled into a sheet using a double-roll press, the roll temperature is controlled between 100°C and 140°C (to maintain a certain fluidity but not adhere to the rolls), and the roll distance is adjusted to control the thickness. Finally, the sheet is pressed into a cake of a specific size using a mold.

[0047] The second method for preparing a flame-retardant masterbatch includes weighing and premixing the components of the flame-retardant masterbatch, and then extruding and granulating the resulting premix in a screw extruder to obtain a flame-retardant masterbatch. Similarly, the processing parameters in the above steps need to be adjusted according to the characteristics of different polymer substrates. For example, the processing temperature for EVA granulation is 120°C to 190°C.

[0048] The raw materials used in the examples and comparative examples of the present invention are all commercially available products.

[0049] (1) Regarding antimony salts: Antimony trioxide was purchased from Hefei Wanran New Materials Technology Co., Ltd., with a CAS number of 1309-64-4, a molecular formula of Sb2O3, and a molecular weight of 291.518. Antimony pentoxide was purchased from Wuhan Jixinyibang Biotechnology Co., Ltd., with a CAS number of 1314-60-9, molecular formula of Sb2O5, and molecular weight of 323.517. Sodium antimonate was purchased from Suzhou Pure Antimony New Materials Co., Ltd. and has a CAS number of 15432-85-6, a molecular formula of NaSbO3, and a molecular weight of 192.73. Note that the market name for sodium antimonate is relatively confusing, and the sodium antimonate used in this invention is different from sodium antimonate trihydrate (NaSbO3·3H2O, molecular weight 246.8) and sodium pyroantimonate (C5H4Na3O6Sb, molecular weight 350.81).

[0050] (2) Regarding phosphates: Strontium hydrogen phosphate was purchased from Wuhan Chengtian Fine Chemical Co., Ltd., with CAS number 13450-99-2, molecular formula SrHPO4, molecular weight 183.599, and purity ≥ 99%. Strontium phosphate was purchased from Hubei Shuaiyan Ligao Biopharmaceutical Co., Ltd., with CAS number 14414-90-5, molecular formula Sr3P2O8, and purity ≥ 98%. Aluminum hypophosphite was purchased from Hefei Wanran New Materials Technology Co., Ltd., with a CAS number of 7784-22-7, a molecular formula of Al(H2PO2)3, and a purity of ≥97%. Melamine polyphosphate (hereinafter abbreviated as MPP) was purchased from Budenheim, with the model number Budit 3141, CAS number 218768-84-4, and molecular formula C3H6N6·(H3PO4) n and Ammonium polyphosphate (hereinafter referred to as APP) was purchased from Shandong Taixing New Materials Co., Ltd., with model number HT-208, CAS number 68333-79-9, and molecular formula (NH4) n +2P n O 3n+1 is.

[0051] (3) Regarding polymer substrates: Taking PVC and EVA as examples, PVC was purchased from Tianjin Bohua Chemical Development Co., Ltd., model number DG-700, and EVA was purchased from Ningbo Shijin Plastics Co., Ltd., for example, US DuPont 210.

[0052] (4) Processing aids: As for the plasticizer, dioctyl phthalate (DOP) was selected and purchased from Shandong Shengfan Chemical Co., Ltd., with CAS number 117-81-7. The dispersant selected was light nano-calcium carbonate, purchased from Shanghai Liangjiang Titanium White Chemical Products Co., Ltd., model number LP-800, with an average particle size of 60nm-100nm. For the stabilizer, a mixture of liquid calcium zinc stabilizer and powder calcium zinc stabilizer with a mass ratio of 3:1 was selected. The liquid calcium zinc stabilizer was purchased from Zhejiang Jiao Environmental Protection Technology Co., Ltd. with model number JCZ-100, and the powder calcium zinc stabilizer was purchased from Zhejiang Jiao Environmental Protection Technology Co., Ltd. with model number JCZ-6503B.

[0053] As for the lubricant, polyethylene wax was selected and purchased from Hebei Tianyu Chemical Co., Ltd., with the model number 110.

[0054] In practical manufacturing applications, many PVC artificial leathers require the lamination of a polyester base fabric to improve tensile strength and comfort. While polyester base fabric is an important component of PVC artificial leather, it is a highly flammable material. To demonstrate the flame retardancy of the material of the present invention and its effectiveness in actual manufacturing, the flame retardancy performance tests in the following examples and comparative examples were conducted by laminating samples containing an antimony-free composite flame retardant to a polyester base fabric and then conducting a flame test. The polyester base fabric was 0.5 mm thick, the PVC sample was 0.6 mm thick, and the total thickness was 1.1 mm. Furthermore, phthalate ester plasticizers, which are commonly used in PVC artificial leather, are also flammable. To enhance the test results, 40% DOP was added to the polymer substrate (PVC) used in the following examples and comparative examples. The present invention will now be described in more detail with reference to Figures 1-5 and the examples and comparative examples.

[0055] Example 1 The composite flame retardant according to the embodiment of the present invention contains, by weight percentage, 30% antimony trioxide and 70% strontium hydrogen phosphate.

[0056] The preparation method of the composite flame retardant includes the steps of weighing each component of the composite flame retardant in the weight percentage, putting them into a mixer, and stirring at a rotation speed of 2000 r / min for 20 minutes until they are uniformly mixed. The combustion results of the flame retardant performance test are shown in Figure 1.

[0057] Examples 2 to 10 In Examples 2 to 10, the specific types and weight percentages of antimony salt and phosphate are adjusted based on the method of Example 1, and the specific technical means can be summarized as "antimony salt + inorganic phosphate". The adjustment conditions are shown in Table 1 below.

[0058] Table 1: Composition of the composite flame retardants of Examples 1 to 10 (units: %) [Table 1]

[0059] Examples 11 to 20 In Examples 11 to 20, the type and weight percentage of phosphate are adjusted based on the method of Example 1, and the specific technical means can be summarized as "antimony salt + inorganic phosphate + MPP". The adjustment conditions are shown in Table 2 below.

[0060] Table 2: Composition of the composite flame retardants of Examples 11 to 20 (units: %) [Table 2]

[0061] Examples 21 to 30 In Examples 21 to 30, the type and weight percentage of phosphate were adjusted according to the method of Example 1, and the specific technical means can be summarized as "antimony salt + inorganic phosphate + APP". The adjustment conditions are shown in Table 3 below.

[0062] Table 3: Composition of the composite flame retardants of Examples 21 to 30 (units: %) [Table 3]

[0063] (Examples 31 to 37) In Examples 31 to 37, the type and weight percentage of phosphate were adjusted according to the method of Example 1, and the specific technical means can be summarized as "antimony salt + inorganic phosphate + MPP + APP". The adjustment conditions are shown in Table 4 below.

[0064] Table 4: Composition of the composite flame retardants of Examples 31 to 37 (units: %) [Table 4]

[0065] (Comparative Example 1) In this comparative example, based on the method of Example 1, all strontium hydrogen phosphate was replaced with MPP.

[0066] (Comparative Example 2) In this comparative example, based on the method of Example 1, all of the strontium hydrogen phosphate was replaced with APP.

[0067] (Comparative Example 3) In this comparative example, the method of Example 1 was followed, but strontium hydrogen phosphate was replaced with a mixture of 45% MPP and 25% APP.

[0068] Performance Detection Test Flame retardant performance tests were carried out on the flame retardants of Examples 1 to 37 and Comparative Examples 1 to 3. The present invention is exemplified by application to PVC artificial leather interior materials for automobiles, and the following samples of Group (1) and Group (2) were set.

[0069] For the samples in group (1), 5 g of the flame-retardant masterbatch of each example and comparative example and 100 g of the polyvinyl chloride masterbatch were rolled and molded using two rolls to obtain samples with dimensions of 356 mm × 100 mm × 1.1 mm, where the thickness of the polyester base fabric was 0.5 mm and the thickness of the PVC sample was 0.6 mm.

[0070] For the samples in group (2), 3 g of the flame-retardant masterbatch of each example and comparative example and 100 g of the polyvinyl chloride masterbatch were rolled and molded using two rolls to obtain samples with dimensions of 356 mm × 100 mm × 1.1 mm, with the polyester base fabric having a thickness of 0.5 mm and the PVC sample having a thickness of 0.6 mm.

[0071] The above samples were subjected to a flame retardancy test, specifically, with reference to GB8410-2006, Combustion Characteristics of Automotive Interior Materials. The samples were clamped at both sides and one end with a U-shaped bracket, and a gas lamp was lit in a combustion chamber with a flame height of 38 mm. The free end of the sample was placed in the flame and ignited for 15 seconds, after which the flame was extinguished.

[0072] The flame burns forward from the free end of the sample. As shown in Figure 1, the first reference line 1 is located at a linear distance of 38 mm along the combustion direction from the free end of the sample, and the second reference line 2 is located at a linear distance of 254 mm along the combustion direction from the first reference line of the sample.

[0073] Start timing from the moment when the root of the propagating flame passes through the first reference line 1. Pay attention to observing the flame propagation situation on the surface where the combustion is fast. For timing, use the surface where the flame propagation is fast as the reference. When the flame reaches the second reference line 2 or is extinguished before reaching the second reference line 2, stop the timing simultaneously. For timing, also use the surface where the flame propagation is fast as the reference.

[0074] If the sample is exposed to the flame for 15 seconds and the ignition source sample is not burning or the sample can burn but is extinguished before the flame reaches the first reference line 1, it is considered to meet the combustion speed requirement. Mark both combustion levels as A. From the test timing, if the flame self - extinguishes within 60 seconds and the combustion distance ≤ 88 mm (calculated from the free end), it is also considered to meet the combustion speed requirement. Mark the combustion level as B. If the flame extinguishes between the first reference line 1 and the second reference line 2 from the combustion time measurement, it is a self - extinguishing sample, and the combustion situation is different from the result shown in the requirement of item 2, that is, the combustion distance is 88 mm < x ≤ 292 mm (calculated from the free end). Mark the combustion level as C. If the flame reaches the second reference line 2 (combustion distance > 292 mm (calculated from the free end)) from the combustion time measurement or the sample burns slowly for a long time (the test ends when timing up to 20 minutes), mark the combustion level as D. The above - mentioned combustion distance is the length of the part where the surface or inside of the sample is burned out.

[0075] The detection results are shown in Table 5 below.

[0076] Table 5 Performance Detection Results of Examples 1 - 37 and Comparative Examples 1 - 3

Table 5

[0077] As shown in Table 6 above, the phosphates used in Examples 2 and 3 were strontium phosphate and aluminum hypophosphite, and the flame retardant effect of the resulting composite flame retardant was lower than that of Example 1 using strontium hydrogen phosphate. The amount of antimony salt used in Example 4 was relatively small, and the amount of antimony salt used in Example 5 was relatively large. The flame retardant effect of the resulting composite flame retardant was lower than that of Example 1, but the flame retardant effects of Examples 1 to 5 were all better than those of Comparative Examples 1 to 3. The compounding effect of "antimony salt + specific phosphate" of the present invention is not only significantly better than that of the conventional "antimony salt + general phosphorus nitrogen-based flame retardant MPP, APP" but is also comparable to that of conventional pure antimony trioxide. This achieves the goal of a flame retardant with low antimony content having excellent flame retardant effect, which can reduce dependence on antimony resources to a certain extent, reduce costs, and be well suited to the flame-retardant polymer material market.

[0078] Furthermore, the antimony salts used in Examples 6 and 7 were antimony pentoxide and sodium antimonate. These two examples demonstrate that the antimony salts used in the present application are not limited to antimony trioxide, but also apply to antimony pentoxide and sodium antimonate, and the corresponding flame retardant effects are antimony trioxide > sodium antimonate > antimony pentoxide.

[0079] In Examples 8 to 10, the blending ratio of each component of the phosphate was adjusted, and in combination with the detection results, it was found that the flame retardant effect of strontium hydrogen phosphate was superior to that of strontium phosphate and aluminum hypophosphite.

[0080] Examples 11-20 are technical solutions based on "antimony salt + inorganic phosphate + MPP", Examples 21-30 are technical solutions based on "antimony salt + inorganic phosphate + APP", and Examples 31-37 are technical solutions based on "antimony salt + inorganic phosphate + MPP + APP". Comparing the detection results of Examples 1-10 with Examples 11-20, Examples 21-30, and Examples 31-37, it can be seen that blending inorganic phosphate with MPP and / or APP can effectively improve the flame retardant effect of the composite flame retardant. In particular, when inorganic phosphate is blended with both MPP and APP, the flame retardant effect obtained is significantly better than that obtained when inorganic phosphate is simply blended with MPP or when inorganic phosphate is simply blended with APP.

[0081] (Examples 38 to 44) The above examples are all intended to provide a composite flame-retardant masterbatch, which comprises, by weight percentage, 20% to 95% of a composite flame retardant, 0% to 16% of a polymer base material, and 5% to 64% of a processing aid.

[0082] In Examples 38 to 40 and Examples 42 to 44, all of the products were prepared in the form of a PVC color cake structure. The specific preparation method includes the steps of weighing and premixing a set amount of composite flame retardant, PVC, and processing aid, feeding the resulting premix into an internal mixer, controlling the temperature of the internal mixer to maintain it within the range of 130 to 150°C for 35 minutes, melting the PVC by mechanical shear heating and mixing it uniformly with other components, rolling it into a sheet using a double roll press, controlling the roll temperature to 100 to 140°C (maintaining a certain fluidity but not sticking to the roll), and cutting it with a cutter to obtain a PVC flame-retardant color cake.

[0083] In Example 41, it is prepared in the form of mixed powder, and the specific preparation method includes the steps of weighing a set amount of composite flame retardant and processing aid, putting them into a mixer, and stirring them uniformly to obtain the mixture.

[0084] In addition, in Examples 38 to 40, the composite flame retardant obtained in Example 1 was used, and the amount of each component of the composite flame-retardant masterbatch was adjusted. In Examples 42, 43, and 44, the composite flame retardants obtained in Examples 11, 21, and 31 were used, respectively. For the composition of each component of the composite flame-retardant masterbatch, see Table 6 below.

[0085] Table 6: Composition of composite flame-retardant masterbatches of Examples 38 to 44 (units: %) [Table 6]

[0086] Example 45 This example provides a method for producing a composite flame-retardant masterbatch with an EVA masterbatch structure, which is produced in the form of a granular structure. The method specifically includes the steps of weighing 72% of the composite flame retardant obtained in Example 1, 15% EVA, 11% light nano-calcium carbonate, and 2% polyethylene wax, adding them to a twin-screw extruder, controlling the cylinder temperature gradient of the twin-screw extruder so that the feed section is 120°C to 140°C, the compression section is 140°C to 160°C, and the extrusion section is 160°C to 180°C, and cooling the extruded material, followed by granulation and drying to obtain an EVA flame-retardant masterbatch.

[0087] Flame retardant performance tests were conducted on the composite flame retardant masterbatches of Examples 38 to 45. Similarly, using the application of flame retardant to 100 grams of PVC manufacturing mixture for PVC artificial leather interior materials for automobiles as an example, samples of Groups (1) and (2) were set up. 6.94 g of flame retardant was added to the sample of Group (1) (ensuring that approximately 5 g of composite flame retardant was added in Examples 38, 42 to 45), and 4.17 g of flame retardant was added to the sample of Group (2) (ensuring that approximately 3 g of composite flame retardant was added in Examples 38, 42 to 45). The test method was the same as above, and the test results are shown in Table 7 below.

[0088] Table 7 Performance detection results for Examples 38 to 45 [Table 7]

[0089] As shown in Table 7 above, Examples 38 to 45 all have excellent flame retardant effects. Comparing the results of Example 38 with Example 1, Example 42 with Example 11, Example 43 with Example 21, and Example 44 with Example 31, it can be seen that the composite flame retardant of the present invention can be fully and effectively exerted in the form of direct addition, and the flame retardant performance of the composite flame retardant can be effectively exerted in the form of a masterbatch. Therefore, it can be seen that the composite flame retardant of the present invention can be used directly, or can be prepared in a color cake structure or granular structure for easy storage and transportation, as needed.

[0090] In addition, referring to the results of Examples 38 and 45, it can be seen that a better flame retardant effect can be achieved in the form of EVA masterbatch, based on the need to add a certain amount of plasticizer (dioctyl phthalate) during the processing of PVC color cake. EVA masterbatch can moderately reduce the flame retardant effect of plasticizer on the composite flame retardant by reducing the addition of plasticizer.

[0091] The specific examples are merely illustrative of the present invention and do not limit the present invention. After reading this specification, a person skilled in the art may make modifications to the examples as necessary without making any creative contribution, but the modifications will be protected by patent law as long as they are within the scope of the claims of the present invention. [Explanation of symbols]

[0092] 1 1st marked line 2 Second marked line

Claims

1. The composition comprises, by weight percentage, 15% to 65% of one or more of antimony trioxide, antimony pentoxide, and sodium antimonate, and 35% to 85% of phosphates including one or more of strontium hydrogen phosphate and strontium phosphate, A composite flame retardant characterized by:

2. The phosphate salts comprise, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 90% strontium phosphate, and 0% to 90% aluminum hypophosphite; The composite flame retardant according to claim 1 .

3. The phosphate salts comprise, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 80% strontium phosphate, 0% to 80% aluminum hypophosphite, and 10% to 90% melamine polyphosphate; The composite flame retardant according to claim 2 .

4. The phosphate salts comprise, by weight percentage, 10% to 90% strontium hydrogen phosphate, 0% to 80% strontium phosphate, 0% to 80% aluminum hypophosphite, and 10% to 90% ammonium polyphosphate; The composite flame retardant according to claim 2 .

5. The phosphate salts include, by weight percentage, 10% to 80% strontium hydrogen phosphate, 0% to 70% strontium phosphate, 0% to 70% aluminum hypophosphite, 10% to 80% melamine polyphosphate, and 10% to 80% ammonium polyphosphate. The composite flame retardant according to claim 2 .

6. In weight percentage, the composite flame retardant according to any one of claims 1 to 5 is 20% to 95%, the polymer base is more than 0% and not more than 16%, and the processing aid is 5% to 64%. A composite flame-retardant masterbatch characterized by:

7. The polymer substrate is one or more of an olefin-based polymer, an ester-based polymer, an ethylene-based polymer, a styrene-based polymer, and a polyurethane.

7. The composite flame-retardant masterbatch according to claim 6.

8. The method includes the steps of weighing and premixing each component according to the compounding components of the composite flame-retardant masterbatch according to claim 6, introducing the resulting premix into an internal mixer, uniformly mixing, grinding and dispersing, and then press-molding and cutting to obtain a cake-like structure composite flame-retardant masterbatch. A method for producing a composite flame-retardant masterbatch.

9. The method includes the steps of weighing and premixing each component according to the compounding components of the composite flame-retardant masterbatch according to claim 6, and then feeding the resulting premix into a screw extruder to extrusion granulate the composite flame-retardant masterbatch with a granular structure. A method for producing a composite flame-retardant masterbatch.

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